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  Subjects -> ELECTRONICS (Total: 175 journals)
Showing 1 - 200 of 277 Journals sorted alphabetically
Acta Electronica Malaysia     Open Access  
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 7)
Advances in Electrical and Electronic Engineering     Open Access   (Followers: 5)
Advances in Electronics     Open Access   (Followers: 76)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Microelectronic Engineering     Open Access   (Followers: 13)
Advances in Power Electronics     Open Access   (Followers: 33)
Advancing Microelectronics     Hybrid Journal  
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 305)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 24)
Annals of Telecommunications     Hybrid Journal   (Followers: 9)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 9)
Archives of Electrical Engineering     Open Access   (Followers: 13)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 28)
Bioelectronics in Medicine     Hybrid Journal  
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 19)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 35)
Biomedical Instrumentation & Technology     Hybrid Journal   (Followers: 6)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 12)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 1)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access   (Followers: 1)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 44)
China Communications     Full-text available via subscription   (Followers: 8)
Chinese Journal of Electronics     Hybrid Journal  
Circuits and Systems     Open Access   (Followers: 15)
Consumer Electronics Times     Open Access   (Followers: 5)
Control Systems     Hybrid Journal   (Followers: 253)
Edu Elektrika Journal     Open Access   (Followers: 1)
Electrica     Open Access  
Electronic Design     Partially Free   (Followers: 104)
Electronic Markets     Hybrid Journal   (Followers: 7)
Electronic Materials Letters     Hybrid Journal   (Followers: 4)
Electronics     Open Access   (Followers: 85)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 10)
Electronics For You     Partially Free   (Followers: 91)
Electronics Letters     Hybrid Journal   (Followers: 26)
Elkha : Jurnal Teknik Elektro     Open Access  
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 50)
Energy Harvesting and Systems     Hybrid Journal   (Followers: 4)
Energy Storage Materials     Full-text available via subscription   (Followers: 2)
EPJ Quantum Technology     Open Access  
EURASIP Journal on Embedded Systems     Open Access   (Followers: 11)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 6)
Foundations and Trends® in Signal Processing     Full-text available via subscription   (Followers: 10)
Frequenz     Hybrid Journal   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 1)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 185)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IACR Transactions on Symmetric Cryptology     Open Access  
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 96)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 77)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 46)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 9)
IEEE Journal on Exploratory Solid-State Computational Devices and Circuits     Hybrid Journal   (Followers: 1)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 65)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 69)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 55)
IEEE Transactions on Circuits and Systems for Video Technology     Hybrid Journal   (Followers: 19)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 39)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 19)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 26)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 70)
IEEE Transactions on Signal and Information Processing over Networks     Full-text available via subscription   (Followers: 11)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 12)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 5)
IET Cyber-Physical Systems : Theory & Applications     Open Access   (Followers: 1)
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 35)
IET Nanodielectrics     Open Access  
IET Power Electronics     Hybrid Journal   (Followers: 45)
IET Smart Grid     Open Access  
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 18)
IETE Journal of Education     Open Access   (Followers: 4)
IETE Journal of Research     Open Access   (Followers: 11)
IETE Technical Review     Open Access   (Followers: 13)
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems)     Open Access   (Followers: 3)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 57)
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 24)
Informatik-Spektrum     Hybrid Journal   (Followers: 2)
Instabilities in Silicon Devices     Full-text available via subscription   (Followers: 1)
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 12)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 18)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 10)
International Journal of Antennas and Propagation     Open Access   (Followers: 11)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 5)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 6)
International Journal of Control     Hybrid Journal   (Followers: 12)
International Journal of Electronics     Hybrid Journal   (Followers: 7)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 13)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 2)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Image, Graphics and Signal Processing     Open Access   (Followers: 14)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 8)
International Journal of Nano Devices, Sensors and Systems     Open Access   (Followers: 12)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 4)
International Journal of Power Electronics     Hybrid Journal   (Followers: 24)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 4)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 10)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 4)
International Journal of Wireless and Microwave Technologies     Open Access   (Followers: 6)
International Transaction of Electrical and Computer Engineers System     Open Access   (Followers: 2)
JAREE (Journal on Advanced Research in Electrical Engineering)     Open Access  
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 3)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 10)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 4)
Journal of Computational Intelligence and Electronic Systems     Full-text available via subscription   (Followers: 1)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 23)
Journal of Electrical Bioimpedance     Open Access   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 7)
Journal of Electrical, Electronics and Informatics     Open Access  
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 7)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 8)
Journal of Electronic Design Technology     Full-text available via subscription   (Followers: 6)
Journal of Electronics (China)     Hybrid Journal   (Followers: 4)
Journal of Energy Storage     Full-text available via subscription   (Followers: 4)
Journal of Field Robotics     Hybrid Journal   (Followers: 2)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 162)
Journal of Information and Telecommunication     Open Access   (Followers: 1)
Journal of Intelligent Procedures in Electrical Technology     Open Access   (Followers: 3)
Journal of Low Power Electronics     Full-text available via subscription   (Followers: 7)
Journal of Low Power Electronics and Applications     Open Access   (Followers: 9)
Journal of Microelectronics and Electronic Packaging     Hybrid Journal  
Journal of Microwave Power and Electromagnetic Energy     Hybrid Journal  
Journal of Microwaves, Optoelectronics and Electromagnetic Applications     Open Access   (Followers: 10)
Journal of Nuclear Cardiology     Hybrid Journal  
Journal of Optoelectronics Engineering     Open Access   (Followers: 4)
Journal of Physics B: Atomic, Molecular and Optical Physics     Hybrid Journal   (Followers: 28)
Journal of Power Electronics & Power Systems     Full-text available via subscription   (Followers: 11)
Journal of Semiconductors     Full-text available via subscription   (Followers: 5)
Journal of Sensors     Open Access   (Followers: 26)
Journal of Signal and Information Processing     Open Access   (Followers: 9)
Jurnal Rekayasa Elektrika     Open Access  
Jurnal Teknik Elektro     Open Access  
Kinetik : Game Technology, Information System, Computer Network, Computing, Electronics, and Control     Open Access  
Learning Technologies, IEEE Transactions on     Hybrid Journal   (Followers: 12)
Magnetics Letters, IEEE     Hybrid Journal   (Followers: 7)
Majalah Ilmiah Teknologi Elektro : Journal of Electrical Technology     Open Access   (Followers: 2)
Metrology and Measurement Systems     Open Access   (Followers: 5)
Microelectronics and Solid State Electronics     Open Access   (Followers: 18)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 33)
Nanotechnology, Science and Applications     Open Access   (Followers: 6)
Nature Electronics     Hybrid Journal  
Networks: an International Journal     Hybrid Journal   (Followers: 6)
Open Journal of Antennas and Propagation     Open Access   (Followers: 8)
Optical Communications and Networking, IEEE/OSA Journal of     Full-text available via subscription   (Followers: 15)
Paladyn. Journal of Behavioral Robotics     Open Access   (Followers: 1)
Power Electronics and Drives     Open Access   (Followers: 1)
Problemy Peredachi Informatsii     Full-text available via subscription  
Progress in Quantum Electronics     Full-text available via subscription   (Followers: 7)
Pulse     Full-text available via subscription   (Followers: 5)
Radiophysics and Quantum Electronics     Hybrid Journal   (Followers: 2)
Recent Advances in Communications and Networking Technology     Hybrid Journal   (Followers: 3)
Recent Advances in Electrical & Electronic Engineering     Hybrid Journal   (Followers: 9)
Research & Reviews : Journal of Embedded System & Applications     Full-text available via subscription   (Followers: 5)
Security and Communication Networks     Hybrid Journal   (Followers: 2)
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of     Hybrid Journal   (Followers: 53)
Semiconductors and Semimetals     Full-text available via subscription   (Followers: 1)
Sensing and Imaging : An International Journal     Hybrid Journal   (Followers: 2)
Services Computing, IEEE Transactions on     Hybrid Journal   (Followers: 4)
Software Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 75)
Solid-State Circuits Magazine, IEEE     Hybrid Journal   (Followers: 13)
Solid-State Electronics     Hybrid Journal   (Followers: 9)
Superconductor Science and Technology     Hybrid Journal   (Followers: 2)
Synthesis Lectures on Power Electronics     Full-text available via subscription   (Followers: 3)
Technical Report Electronics and Computer Engineering     Open Access  
TELE     Open Access  
Telematique     Open Access  
TELKOMNIKA (Telecommunication, Computing, Electronics and Control)     Open Access   (Followers: 8)
Universal Journal of Electrical and Electronic Engineering     Open Access   (Followers: 6)
Visión Electrónica : algo más que un estado sólido     Open Access   (Followers: 1)
Wireless and Mobile Technologies     Open Access   (Followers: 6)
Wireless Power Transfer     Full-text available via subscription   (Followers: 4)
Women in Engineering Magazine, IEEE     Full-text available via subscription   (Followers: 11)
Електротехніка і Електромеханіка     Open Access  

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Journal Cover
Journal of Energy Storage
Journal Prestige (SJR): 0.84
Citation Impact (citeScore): 4
Number of Followers: 4  
  Full-text available via subscription Subscription journal
ISSN (Print) 2352-152X
Published by Elsevier Homepage  [3161 journals]
  • A comparison of system architectures for high-voltage electric vehicle
           batteries in stationary applications
    • Abstract: Publication date: October 2018Source: Journal of Energy Storage, Volume 19Author(s): Michaela Bauer, Julian Wiesmeier, John Lygeros An increasing global interest in clean energy alternatives requires new concepts for local storage of electricity. This leads to new research demand regarding suitable system architectures based on high-voltage batteries from electric vehicles. In this study, a new method for evaluating stationary system architectures is described. The assessment focuses on the system efficiency of different architectures. A sensitivity analysis is included to show further distinctions in criteria such as volume, weight and cost. Three system topologies for the use of new and second-hand batteries extracted from electric vehicles in stationary applications are presented. All components need to be able to operate in a bidirectional mode — the ability to absorb and release electricity from and into the grid. The first two topologies include one battery connected to the grid either with a DC/DC converter and a DC/AC inverter or with a DC/AC inverter and a transformer. The third topology involves the connection of two batteries in series with a DC/AC inverter, providing better characteristics in terms of the required power electronic components. The results show differences between one to two percentage points in efficiency. Moreover, the influence of parallelisation and various power distributions delivers close to five percentage points higher efficiency for the first topology with a DC/DC converter. Combined with the outcome of the sensitivity analysis, the topology with the DC/DC converter connected to the DC/AC inverter exhibits the best performance in the overall evaluation criteria.
  • Heat Transfer and Pressure Drop in a Circular Tube Fitted with Twisted
           Tape Insert Having Continuous Cut Edges
    • Abstract: Publication date: October 2018Source: Journal of Energy Storage, Volume 19Author(s): R.M. Sarviya, Veeresh Fuskele The experimental work on heat transfer augmentation using a new kind of insert called twisted tape with continuous cut edges is carried out. The work includes the determination of friction factor and Nusselt number for new twisted tape insert having different twist ratios of 3 & 5. The experimental data obtained from plain tube and conventional twisted tape were verified with the standard correlations to ensure the validation of experimental results. The results of new twisted tape of different twist ratios have been compared with the values for the plain tube and tube with conventional twisted tape. In addition, the effects of the new twisted tape insert on the thermal performance factor are also investigated. The results obtained lead to the conclusion that higher heat transfer rates can be achieved using twisted tape inserts with continuous cut edges at the expense of a reasonable pressure drop.
  • Exploratory investigation of a new thermal energy storage system with
           different phase change materials having distinct melting temperatures
    • Abstract: Publication date: October 2018Source: Journal of Energy Storage, Volume 19Author(s): Pardeep Singh Bains, Harmeet Singh This paper presents the experimental investigation of the new thermal energy storage system comprising of different PCMs. Three PCMs having different melting temperatures are used to investigate the performance of the system and water is used as a heat transfer fluid (HTF). Spherical AISI 304 L capsules of 55 mm diameter were used to encapsulate the phase-change material. The whole system was operated between different temperature ranges, and HTF (heat transfer fluid) flow was varied from 2 liters/min to 6 liters/min. The temperature inside the bed was continuously monitored using LABVIEW express during the charging and discharging procedures. The effect of inlet temperature and HTF flow rate on the performance of the system was also assessed in the experimental work. The study demonstrates that there is a decrease in the charging time of the packed bed from 28% to 14% when flow rate is increased from 2 liters/min to 6 liters/min. Moreover, the energy efficiency also increases by the increase in mass flow rate. It was also found that there is a decrease in exergy efficiency with the increase in mass flow rate.
  • Implementation of an SOC-based four-stage constant current charger for
           Li-ion batteries
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Chien-Hsing Lee, Ming-Yang Chen, Shih-Hsien Hsu, Joe-Air Jiang This study implements a possible use of the state of charge (SOC) instead of the charge voltage limit (Vlimit) to control the charging process for a four-stage constant current charging strategy. To determine the charging current in each stage, an iterative optimization procedure based on Taguchi method is employed to find near-optimal values. To control the change of the charging stage and terminate the charging process, the Coulomb counting method combined with battery’s open circuit voltage estimation is adopted for SOC estimation. Tests of Sanyo 840 mA h, 3.6 V lithium-ion (Li-ion) batteries have been conducted with a Keithley 2230-30-1 triple power supply and a Prodigit 3332 F dual electronic load. The implemented charger has an input voltage of 12 V, output currents of 1.176 A, 0.840 A, 0.588 A, and 0.336 A, as well as an output voltage ranged from 0.168 V to 0.588 V. By performing the experiments, the proposed charging strategy has shorter charging time than the equivalent constant current constant voltage (CCCV) and the Vlimit-based charging methods. However, it yields a slightly lower charging efficiency than the equivalent CCCV and pulse current charging methods.
  • Electromotive force characterization of secondary battery cells using
           estimated electrolyte molality
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): A. Janse van Rensburg, G. van Schoor, P.A. van Vuuren Existing methods for electromotive force (EMF) characterization that make use of readily available data, such as terminal voltage and applied current, require a significant time commitment and a constant temperature environment. Both linear interpolation and extrapolation rely on state-of-charge (SOC) calculation by Coulomb-counting which only serves to reduce the accuracy of the resulting EMF-SOC curve(s). A battery management system requires accurate EMF-SOC data for periodic recalibration otherwise it cannot apply proper charge control. This paper presents an alternative concentration-based method for EMF characterization and the key lies in the fact that molality is not influenced by temperature. A modified version of the Nernst equation and temperature-compensated open-circuit voltage measurements are used to estimate the molality when the cell is at rest. During operation, the energy into or out of the cell is mapped to changes in the estimated molality to calculate the EMF as the cell charges or discharges. The concentration-based method is verified using experimental data from valve-regulated lead-acid cells and its EMF curves are compared to those of linear interpolation and extrapolation. The proposed method has less stringent practical requirements and validation results indicate a significant improvement in accuracy and applicability over the existing methods.
  • Critical electrode properties and drying conditions causing component
           segregation in graphitic anodes for lithium-ion batteries
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Bastian G. Westphal, Arno Kwade Among others, the performance of lithium-ion batteries is determined by the structure and material distribution of the electrodes. These electrodes are known to develop an inhomogeneous inactive material distribution during drying of the wet-coated film. The segregation of the conductive additive and the binder was found for the graphite anodes studied in this work and was proven by indirect and direct analyses. Segregation reduces the adhesion strength between coating and substrate and increases the electrical resistance as well as the elasticity of the anode. It was found by spectroscopic analysis that binder concentration and by association carbon black concentration increase from bottom to top of the coating. This Segregation increases with drying temperature and the amount of solvent that needs to evaporate. An auxiliary parameter is introduced to determine a combined, critical value for the driving force of the solvent evaporation (drying temperature) and the anodes’ mass loading. Finally, the mass loading and/or the drying temperature to avoid segregation can be estimated with regard to the final product and the existing drying equipment.
  • Coordinated optimization and control of SFCL and SMES for mitigation of
           SSR using HBB-BC algorithm in a fuzzy framework
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Mostafa Sedighizadeh, Masoud Esmaili, Hesam Parvaneh Increasing demand for electrical power and expensive expansion of power systems to meet this demand leads the planners to find techno-economical solutions to overcome these challenges. Using series capacitors as reactive power compensation devices in a long transmission lines is a well-known and suitable way to face these challenges in power systems. Transmitted electrical power and the stability margin of power systems are economically improved by the proposed series devices. However, employing the series capacitors in long transmission lines causes a well-known problem in power systems as Sub Synchronous Resonance (SSR). In the present work, the mitigation of SSR is formulated as a Multi Objective Problem (MOP) in a fuzzy framework by using optimal coordinated control of Superconducting Fault Current Limiter (SFCL) and Superconducting Magnetic Energy Storage (SMES). Objective functions of MOP includes the minimization of the initial energy stored in the SMES unit, the energy loss of SFCL, the kinetic energy in generator rotor, the active power deviations in faulted bus, and the rotor speed deviations. These five objective functions are scaled by a fuzzy operator, then the scaled objective functions are aggregated by the “max-geometric mean” operator to generate the multi objective function. To solve the proposed multi-objective problem, the Hybrid Big Bang-Big Crunch (HBB-BC) as a meta-heuristic optimization algorithm is used. In order to evaluate the efficiency of the proposed algorithm, it is implemented on the IEEE First Benchmark Model (FBM) for SSR studies. According to the simulation results of the present study, the proposed algorithm is more effective in reducing the SSR problem in comparison with other algorithms.
  • Experimental investigation of transient melting and heat transfer behavior
           of nanoparticle-enriched PCM in a rectangular enclosure
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Mohammad Bashar, Kamran Siddiqui An experimental study was conducted to investigate the transient melting and heat transfer behavior of nanoparticle-PCM mixtures in a rectangular enclosure. Four types of nanoparticles, silver, copper oxide, aluminum oxide and multi-walled carbon nanotubes were considered, and paraffin wax was used as the PCM. The results show that all four nanoparticle-enriched PCM mixtures provided better thermal performance as compared to the case with the plain PCM. It has been argued that the addition of surfactant to improve the suspension-ability of nanoparticles in the PCM counteracted the viscosity enhancement due to nanoparticles in the PCM. Among the four tested nanoparticles, silver nanoparticles were found to be the most effective in the heat transfer enhancement, followed by copper oxide nanoparticles. The performances of aluminum oxide and MWCNT were hampered due to their higher settlement rates. The transient heat transfer coefficients for all cases were computed and found to have increased rapidly in the early stages of melting up to the melted fraction of about 0.2, after that they remained almost constant for the rest of the melting process. The heat transfer coefficients for CuO and silver were found to be about 18% and 14% higher than the plain PCM case, while aluminum oxide and MWCNT were lower and closer to the plain PCM case due to higher sinking rates. The thermal behavior of CuO-enriched PCM was further investigated for 1, 3, 6, 8 and 10% mass fractions of CuO. It was found that under given conditions, 6% CuO fraction provides the best thermal performance and highest melting rate. For this case, the melting rate and heat flux were about 25% higher than that for the plain PCM case.
  • Predicting the battery core temperature: Explanatory power of measurement
           quantities under different uncertainty scenarios
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Julian Mehne, Wolfgang Nowak Predicting the highest battery temperature, the core temperature, is an important task for the safe operation of lithium-ion batteries. This prediction task is complicated by inherent system uncertainties that result in uncertain core temperature estimates. Aside from model, parameter and measurement uncertainty, this also includes uncertain user behavior in form of uncertain future discharge currents. However, measurable quantities like voltage, surface temperature or discharge current can potentially decrease the uncertainty in predicting the core temperature. The extent to which a measurement is able to decrease this estimation uncertainty, called data worth, depends on the uncertainty scenario. We conduct a model-based study to investigate the potential of voltage, current and surface temperature measurements to decrease core temperature estimation uncertainty. We use our previously developed stochastic, physically-based battery model to estimate the core battery temperature of a cylindrical LiFePO4-Graphite cell. The data worth is computed with the Preposterior Data Impact Accessor method. We find that the common input to state-of-charge estimation methods, i.e. voltage and current measurements, can theoretically partially substitute a temperature measurement, if the user behavior is anticipated to some degree. Moreover, we highlight the importance of adequately estimating the involved uncertainties when assessing the data worth of measurement quantities.
  • Life cycle prediction of Sealed Lead Acid batteries based on a Weibull
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Yemeserach Mekonnen, Haneen Aburbu, Arif Sarwat The performance and life cycle of Sealed Lead Acid (SLA) batteries for Advanced Metering Infrastructure (AMI) application is considered in this paper. Cyclic test and thermal accelerated aging test is performed to analyze the aging mechanism resulting in gradual loss of performance and finally to battery's end of service life. The objective of this study is to confirm design concepts, find the life characteristic and develop standard information on failure rates and mechanisms. Reliability assessment of the SLA is evaluated using different parametric distribution analysis models and best fit distribution is selected based on Anderson–Darling adjustment value. Shape parameter (β), scale parameter (α) and threshold parameter (λ) of the selected Weibull distribution is computed from experimental cycle life test data. Thermally accelerated aging test of SLA is performed and analyzed. Failure times are extrapolated to predict the lifetimes at the desired operational field temperature.
  • Passivity-based PI control of a SMES system to support power in electrical
           grids: A bilinear approach
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Walter Gil-González, Oscar Danilo Montoya A bilinear proportional-integral (PI) controller based on passivity-based formulations for integrating superconducting magnetic energy storage (SMES) devices to power ac microgrids is proposed in this paper. A cascade connection between a dc–dc chopper and a voltage source converter is made to integrate the SMES system. The proposed controller guarantees asymptotically stability in the Lyapunov's sense under closed-loop operation. This controller exploits the well-known advantages of the proportional-integral (PI) actions via passivation theory. Active and reactive power compensation in the ac system through the SMES integration is proposed as the control objective. To achieve this goal, a radial ac distribution feeder with high penetration of distributed energy resources and time-varying loads is employed. The effectiveness and the robustness of the proposed bilinear PI controller verified by comparing its dynamical performance to conventional approaches such as conventional PI and feedback controllers. All simulation results are conducted via MATLAB/SIMULINK software by using SimPowerSystem library.
  • Time-of-use and time-of-export tariffs for home batteries: Effects on low
           voltage distribution networks
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Andrew J. Pimm, Tim T. Cockerill, Peter G. Taylor Time-of-use electricity tariffs are gradually being introduced around the world to expose consumers to the time-dependency of demand, however their effects on peak flows in distribution networks, particularly in areas with domestic energy storage, are little understood. This paper presents investigations into the impact of time-of-use and time-of-export tariffs in residential areas with various penetrations of battery storage, rooftop solar PV, and heat pumps. By simulating battery operation in response to high resolution household-level electrical and thermal demand data, it is found that home batteries operating to maximise cost savings in houses signed up to time-dependent tariffs cause little reduction in import and export peaks at the low voltage level, largely because domestic import and export peaks are spread out over time. When operating to maximise savings from the first three-tier time-of-use tariff introduced in the UK, batteries could even cause increases in peak demand at low voltage substations, if many batteries in the area commence charging at the start of the overnight off-peak price band. Home batteries operating according to time-dependent electricity tariffs significantly miss out on the potential peak shaving that could otherwise be achieved through dedicated peak shaving incentives schemes and smarter storage control strategies.
  • Enhancement in peak shifting and shaving potential of electrically heated
           floor residential buildings using heat extraction system
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Ying Sun, Karthik Panchabikesan, Mahmood Mastani Joybari, Dave Olsthoorn, Alain Moreau, Miguel Robichaud, Fariborz Haghighat Peak shifting plays a vital role in easing the stress on electrical grids as well as in reducing the electricity bill for consumers by taking benefit of the time-of-use tariff. In cold climates, this can be achieved effectively by storing the heat during off-peak periods and releasing it during peak periods. In this regard, electrically heated floor (EHF) with high thermal mass (e.g. bricks, concrete) can be beneficial. However, residential buildings in places like North America face practical constraints for incorporating high thermal mass on each floor. To overcome this limitation, the present work proposes a forced ventilation system or also called as heat extraction system (HES) to transfer the heat from zones that are heated by EHF with high thermal mass to zones with no such provisions. In this study, an experimental house (multistory), in which the EHF is mainly installed on the basement floor is modeled and validated using the field measurement data. The validated model is then utilized to conduct parametric analysis (effect of air flow rate and outlet location) for investigating the performance of HES and to evaluate its peak shaving potential. Simulation results show that HES increases the peak shifting potential of EHF up to 19%. On the other hand, it is also inferred that the proposed methodology increases the energy consumption by 18% but decreases the daily heating cost by 24%. It should be mentioned that the increase in energy consumption is due to the prolonged operation of the basement EHF during the off-peak period and the decrease in energy cost is because of shifting the peak to the off-peak period. The proposed concept would be a benefit to both the supplier and consumer in terms of peak shifting and heating cost saving.
  • Evaluation of cyclic aging tests of prismatic automotive
           LiNiMnCoO2-Graphite cells considering influence of homogeneity and anode
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Meinert Lewerenz, Dirk Uwe Sauer Cyclic aging tests of 20 compressed prismatic automotive Li(NiMnCo)O2 Graphite cells are evaluated. The shallow cyclic aging tests are conducted around five average SOCs with respect to the anode. The cells are cycled at two DODs and two C-rates. The irreversible capacity loss is evaluated by the slope of the near-linear part at the end of aging test. The homogeneity of lithium distribution (HLD) is associated with peak height of differential voltage analysis (DVA) and to capacity difference analysis (CDA). The evaluations of DVA, CDA and capacity fade curve are depending mainly on the average SOC and hardly on DOD or C-rate. The trends correlate with the volume expansion originated from the graphite. The highest HLD and the lowest capacity fade are reached around 50% SOC where hardly any additional volume expansion occurs. In the SOC regions with high volume expansion of the graphite the HLD reduces dramatically and the capacity fade rises towards 0% and 100%, respectively. Due to smeared characteristics in DVA, capacity loss cannot be directly separated into shares related to anode overhang, HLD, loss of active material and residual irreversible losses. The combination of cell compression and high gradients of volume expansion during shallow cycling is found to be the root cause for the flattening of DVA curves.Graphical abstractGraphical abstract for this article
  • Effect of graphene oxide with different oxygenated groups on the high-rate
           partial-state-of-charge performance of lead-acid batteries
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Weijia Cai, Kai Qi, Zhenyu Chen, Xingpeng Guo, Yubing Qiu Four graphene oxide samples with different oxygenated groups are prepared and characterized, and then employed as the additives in the negative active materials to investigate the effect of different oxygenated groups of graphene oxide on the H2 evolution performance of negative plates and the high-rate partial-state-of-charge cycle life of simulated lead-acid batteries. The results indicate that the H2 evolution and the reduction of PbSO4 processes are largely accelerated by the graphene oxide additives. An increase in CO groups (COH and COC) of graphene oxide can largely promote the H2 evolution process. The addition of the graphene oxide additives largely increases the surface area and total pore volume of the negative plates, meanwhile obviously increases the hydrophilicity of negative active materials to facilitate the diffusion of acid into the inner of the plate. The high-rate partial-state-of-charge cycle life of the simulated test cells containing the graphene oxide samples is prolonged significantly, and especially those containing graphene oxide with less CO groups and more carbonyl and carboxyl groups have the longest cycle life, which seems to be more appropriate as the additive of negative plates.
  • Performance analysis of industrial PCM heat storage lab prototype
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): H.A. Zondag, R. de Boer, S.F. Smeding, J. van der Kamp A 140 l lab scale shell-and-tube PCM heat storage was built and tested, and the experimental results were compared to a numerical model. Natural convection in the PCM was found to significantly influence the local temperature distribution in the storage vessel, which could not be predicted well by the model, since the model assumes only conductive heat transport in the PCM. Nevertheless, the overall thermal power output of the storage could be predicted fairly well, if a correction term was used in the model to compensate for the enhanced heat transfer in the molten PCM. Experimentally, a horizontal orientation was found to be beneficial due to increased heat exchange during charging (melting). Comparing the two PCMs used in the testing (RT70 and MgCl2·6H2O), it was found that the RT70 had stable performance while the salt hydrate showed a reduced melting enthalpy which was ascribed to phase separation. For the RT70, a thermal power of 5 kW is obtained during phase change in the charging phase, and 3.5–2 kW during phase change in the discharging phase, while for MgCl2·6H2O this was 3.5 kW and 3–2 kW respectively.
  • Capacity value of energy storage in distribution networks
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): I. Konstantelos, G. Strbac Security of supply in electricity distribution networks has been traditionally delivered by conventional assets such as transformers and circuits to supply energy to consumers. Although non-network solutions, such as energy storage (ES), can also be used to provide security of supply by carrying out peak shaving and maintaining supply for the duration of a network outage, present network design standards do not provide a framework for quantifying their security contribution and corresponding capacity value. Given the fundamentally different operating principles of ES, it is imperative to develop novel methodologies for assessing its contribution to security of supply and enable a level playing field to be established for future network planning. To this end, a novel probabilistic methodology based on chronological Monte Carlo simulations is developed for computing the Effective Load Carrying Capability (ELCC) of an energy storage plant. Substantial computational speed-up is achieved through event-based modelling and decomposing between energy and power constraints. The paper undertakes, for the first time, the in-depth analysis of key factors that can affect ES security contribution; plant and network outage frequency and duration, network redundancy level, demand shape, islanding operation capability and ES availability. ES capacity value is shown to decrease in networks with an unreliable connection to the grid; time to restore supply is shown to be more important that frequency of faults. Capacity value increases in cases of peaky demand profiles, while the ability to operate in islanded conditions is shown to be a critical factor. These findings highlight the need for sophisticated network design standards. The proposed methodology enables planners to consider ES solutions and allows network and non-network assets to compete on an equal basis for security provision.
  • Management of charging cycles for grid-connected energy storage batteries
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Mohammed Jasim M. Al Essa The use of renewable energy requires a certain level of energy management in electricity distribution grids. Grid-connected energy storage batteries (ESBs) can be utilized to keep this level of management by charging and discharging them accordingly. Grid-connected ESB users schedule their usage based on time-of-use tariffs to follow economic charging cycles. However, charging several grid-connected ESBs during off-peak tariff interval may cause a decline of grid voltage below its limit. Therefore, this paper suggests a management scheme to maintain voltage-sag magnitude within its threshold, while minimizing the aggregated cost of charging the grid-connected ESBs. A sequential quadratic programming technique is employed to solve the objective function, considering an IEEE test system of 37 node. According to optimization results, the management scheme reduces the operational cost of different ESB penetration in the test system, taking into consideration ESB state of charge and grid voltage.
  • Process modeling of the electrode calendering of lithium-ion batteries
           regarding variation of cathode active materials and mass loadings
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Chris Meyer, Malte Kosfeld, Wolfgang Haselrieder, Arno Kwade The process chain for production of lithium-ion battery electrodes commonly includes the compaction by calendering. This process step decisively determines the pore structure of the coating and therefore the electrochemical performance of the produced lithium-ion battery cells. For the targeted adjustment of the pore structure, it is of substantial interest to be able to control this process comprehensively. In this study, a Heckel-based model equation is supplemented by a predictive model for the lowest achievable coating porosity based on the theoretical packing structures of equally sized spheres. Using this approach, the influence of different active materials, varying in particle size distribution and mechanical characteristics, on the compaction behavior is examined. An addition of smaller particles as well as increased initial porosities due to coarser particles decrease the compaction resistance. Furthermore, the impact of increasing mass loadings of the coating on the compaction resistance is analysed, resulting in a linear proportional relationship for the considered range from 80 to 280 g/m2.Graphical abstractGraphical abstract for this article
  • CFD thermal energy storage enhancement of PCM filling a cylindrical cavity
           equipped with submerged heating sources
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): T. Bouhal, Saïf ed-Dîn Fertahi, T. Kousksou, A. Jamil In this paper, two-dimensional CFD simulations were performed to simulate the melting process of a phase change material (PCM) filling a cylindrical cavity which includes heating sources. A CFD model based on the physical enthalpy-porosity formulation was used to simulate the phase change of the solid Gallium and to optimize the geometry of the heating sources according to the operating conditions in terms of the applied temperatures. The geometric effect of the heating sources, as well as the boundary conditions on the heat transfer characteristics are investigated in detail. In fact, the evolution of the temperature, liquid fraction and streamlines contours for the studied configurations, namely the cylindrical heating sources and the heating source with fins for two applied temperatures (Th = 40 °C) and (Th = 45 °C) were carried out. Temperature and liquid fraction measurement were assessed numerically for some specific points located inside the studied configurations for determining the redesign effect of the heating sources. Finally yet importantly, the heat transfer coefficient at the heating sources has been defined as indicator of performance to measure the contribution of the fins in the improvement of the melting time within the cylindrical cavity. It has been found that the cylindrical cavity where four fins are integrated at each heating source have enhanced the heat transfer in the PCM and improved its melting time from 18.35 min to 13.35 min while applying a hot temperature (Th = 40 °C). Furthermore, the configuration with fins enhanced the heat transfer and improved the melting time of the PCM.
  • A comparative study of liquid, solid and hybrid adiabatic compressed air
           energy storage systems
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Haobai Xue, Alexander White The increasing penetration of renewable energy sources into the power grid has prompted the development of many energy storage systems, amongst which Adiabatic Compressed Air Energy Storage (A-CAES) is deemed one of the more promising technologies. A-CAES systems can be categorized into solid A-CAES and liquid A-CAES, both of which have received extensive treatment in the literature. In this paper, thermodynamic and economic models are built for each of these systems and their sub-components, and the appropriate materials are selected for the corresponding Thermal Energy Storage (TES). A hybrid TES system is also considered, combining solid TES for low-pressure air with liquid TES for higher pressure. Results for this are compared with the other two systems. Parametric and optimisation studies have been carried out and suggest that the hybrid system has thermodynamic and economic advantages over the other two. The trade off between efficiency and cost and the factors affecting this trade off are also investigated.
  • Effect of benzoquinone additives on the performance of symmetric
           carbon/carbon capacitors – electrochemical impedance study
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Mikołaj Meller, Krzysztof Fic This paper reports on the electrochemical performance of symmetric carbon/carbon electrochemical capacitors operating in aqueous electrolytic solutions with various benzoquinones as a source of pseudocapacitance. The benzoquinones have been introduced for the enhancement of capacitance values and the energy density in the final device. Three isomers, namely hydroquinone, catechol and resorcinol as electrolyte modifiers displayed different electrochemical activity in acidic electrolyte, affecting final electrochemical performance of the capacitors subjected to investigations. Furthermore, the paper demonstrates the electrochemical impedance spectroscopy as a powerful technique for electrochemical capacitor characterization and discusses the potential risk of the overestimation of the data recorded.
  • Ultra-high temperature thermal energy storage. Part 2: Engineering and
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Adam Robinson The storage of energy at ultra-high temperatures offers many benefits including high energy density and efficient conversion to and from electricity that can be further enhanced by cogeneration. In addition to this, an Ultra-High Temperate thermal energy Storage (UHTS) system would be clean, closed, and reversible and could be built with abundant low cost materials. However, operation at ultra-high temperature is challenging due to the reduced strength and increased reactivity of materials. This paper discusses how a storage system with useful performance can be engineered. In many cases UHTS components and systems can be created by using existing techniques, but in some areas there are engineering challenges that need to be solved before UHTS can become operational. Once the technical and practical feasibility is investigated, there is a brief assessment of the likely capital cost of implementing the storage system at grid scale. As a compact and closed system, UHTS would be inherently suitable for supplying heat at the point of demand. This offers an opportunity to increase the effective roundtrip efficiency to 95%, which far exceeds most other storage methods Beyond this UHTS could be used to aid the transition of a national energy system to all electric renewable operation. The paper closes with a discussion of the complexities and opportunities brought about by the flexibility of configuration and the transient thermal nature of UHTS.Graphical abstractEnergy storage at ultra-high temperatures (1800 K) is clean, reversible and insensitive to deployment location whilst suffering no storage medium degradation over time. Beyond this, it unlocks greater energy densities and competitive electric-to electric recovery efficiencies than other approaches. This paper discusses how a storage system with useful performance can be engineered using existing techniques. There is also an analysis of key components, capital cost and how the system would support a national energy system based on renewable generation.Graphical abstract for this article
  • System identification black box approach for modeling performance of PEM
           fuel cell
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Sudarshan L. Chavan, Dhananjay B. Talange A polymer electrolyte membrane (PEM) fuel cell is very useful for distributed generation and for portable users like electric vehicles because it is very efficient, emission free and operated at low temperature. However, it is not so easy to find direct experimental estimates of the actual performance of PEM fuel cell through various phenomena and operating conditions like chemical reactions, fuel pressure, working temperature and fuel humidity. Mathematical modeling, therefore, plays an important role in understanding operational performance of PEM fuel cell. The actual operating performance of PEM fuel cell depends on a number of parameters, therefore developing an accurate model that includes its dynamic behavior is most important. In this paper, first time, the system identification black box approach is used to develop a number of simple but more realistic mathematical model structures for a PEM fuel cell. The performance of each model structure is compared with the data from a 25 cm2 active area practical PEM fuel cell for result validation. The presented models can be used to predict polarization behavior of the PEM fuel cell under different loading conditions.
  • Topological Considerations on the Use of Batteries to Enhance the
           Reliability of HV-Grids
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): L. Fiorini, M. Aiello, D. Poli, P. Pelacchi The large amount of renewable energy sources (RESs) recently integrated within the electric power systems across the world poses new challenges for their operation. Among several viable solutions, energy storage systems are the most promising to increase reliability and flexibility. This paper proposes a novel topological and probabilistic approach to find the optimal capacity and siting of energy storage devices, in order to increase the system reliability and the hosting capacity of renewables. Wind and solar productions, generators availability, and real-time demand are modeled with proper distribution functions, and the yearly expected energy not supplied is estimated using a sequential Monte Carlo technique. Four siting policies are applied and compared to place the optimal storage capacity on eight grids with different topological characteristics. Power flows are linearized and the optimization of resources is formulated as a linear programming problem. The results show that large-scale batteries operated by the Transmission System Operator can significantly improve system reliability and exploitation of RESs. The presence of energy-hubs and small-world properties strongly increase the transmission effectiveness of weakly- and well-meshed grids. A siting policy based on the Power Transfer Distribution Factors matrix of the grid turns out to be particularly successful.
  • Dimensional analysis and modelling of energy density of lithium-ion
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Collins C. Kwasi-Effah, Timon Rabczuk A number of literature studies have shown that the energy density of lithium ion battery depends majorly on the particle radius, diffusivity, electric conductivity and thickness of the electrode. However, since the discovery of these major parameters, there has been no significant breakthrough in the present design technology to achieve successful design application in the Electric Vehicle industry. The energy density still ranges around 250Wh/kg on improvement and is insignificant compared to the energy produced by the internal combustion engine. Therefore, in this paper dimensional analysis is applied to lithium ion battery’s energy density in order to obtain the sets of parameters that influence the performance with cathode material as reference. Five different cathode materials including; LiMn2O4, LiFePO4, LiCoO2, LiV6O13, and LiTiS2 were used and the ranges for all material properties was selected based on reported data from literature. In order to bridge the gap in literature towards predicting the amount of energy obtainable from a specific electrode design, an empirical energy density model is proposed. Result showed that the specific modulus of the battery’s electrode is a dominant factor for improving the energy density of the lithium ion battery compared to the particle radius, diffusivity and electrode thickness. Thus, in order to achieve a significant breakthrough, electrodes with high specific modulus are required. Designing an electrode with the characteristics of very low density, high compressibility factor, and high young modulus is necessary for an improved system performance. Thus, material combination of LiCoO2/Aqueous-Lithium-air could give a practical breakthrough in achieving very high specific modulus and consequently high energy density. It is therefore suggested that focus on the mechanical/elastic property should not be geared only to its durability but also towards the energy density.
  • Parameter variations within Li-Ion battery packs – Theoretical
           investigations and experimental quantification
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Michael Baumann, Leo Wildfeuer, Stephan Rohr, Markus Lienkamp Single lithium-ion cells within electric vehicles’ battery packs generally show variations in capacity and impedance due to the manufacturing process as well as operational conditions. Therefore, cells connected in parallel experience different dynamic loads during vehicle operation, which may potentially result in uneven and accelerated aging behavior. However, in literature only little is mentioned about the different reasons for parameter variations within single cells of parallel connections as well as their magnitude in real-life conditions. In this work, capacity and impedance variations within parallel-connected cells are investigated theoretically and are quantified exemplary by a batch of new cylindrical 18650 cells as well as an retired BEV battery pack with a 2p96s configuration of prismatic cells. Furthermore, the development of existing parameter variations along cycling are analyzed for two modules of the battery pack. It is demonstrated, that the aged cells show a strong increased parameter spread compared to the new cells. During further aging, the existing capacities spread of the block and especially the state of inhomogeneity of parallel couples increases. Hence, the widespread theory of a self-balancing effect inside a parallel connection, which leads to a convergence of the cells’ SOH, is disproved.
  • Special report on the achievements realized by researchers of Chinese
           Academy of Sciences in the field of energy storage technologies
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Xianfeng Li, Guanglei Cui The inevitable depletion of non-renewable fossil fuels and serious environmental pollution promote the wide application of renewable energies. Most of the renewable energy sources, such as solar and wind power, suffer from uncontrollable as well as complicated situations (Yang et al., 2011) [1]. Electrochemical energy storage technologies are crucial to solve these problems, as they can efficiently store electricity in chemicals and release it according to the users’ demands (Yang et al., 2011; He et al., 2006)[1], [2]. Moreover, energy and environmental challenges have stimulated great interest to replace gasoline engine powered vehicles by plug-in hybrid vehicles (PHEV) and electric vehicles (EVs). Therefore, it is vital to improve the performance of energy storage systems, which depends on the development of key materials for the various batteries and new energy storage strategies. Researchers from Chinese Academy of Science (CAS) have dedicated to the researches of energy storage systems for decades and made significant process. We will introduce the progress on energy storage systems of CAS in recent two years, which covers the key materials of Lithium ion battery (LIB), Lithium-oxygen (Li-O2) battery, Lithium-sulfur (Li-S) battery, Lithium ion capacitor, Sodium ion battery, and Flow battery.
  • Effect of design parameters on the exergy efficiency of a utility-scale
           packed bed
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Bruno Cárdenas, Tristan R. Davenne, James P. Rouse, Seamus D. Garvey The optimization of a packed bed for utility-scale applications is presented herein. The paper discusses comprehensively the effects that particle size, aspect ratio and storage mass have on the exergy losses of the store throughout a complete working-cycle and seeks to provide a clear reference of what is an adequate range of aspect ratios to consider for the design of a grid-scale packed bed. A one-dimensional model that accounts for temperature-dependent properties of both, storage medium and heat transfer fluid, and self-discharge losses is used for performing the analyses. The working cycle considered for the modelling work is a 24 h long sinusoidal profile (12 h charge/12 h discharge) with a 10 MW peak power and a total energy storage requirement of 79.4 MWhth. The results show that a substantial improvement in performance can be achieved by adopting a configuration based on an aspect ratio between 0.5 and 0.8 and fine-tuning the particle size for the specific shape of the container. Furthermore, the study reveals that increasing the thermal storage mass leads to a considerable increase in efficiency. It is determined that a design with 50% additional storage mass, an aspect ratio of 0.6 and a particle size of 3.7 mm, is the optimum configuration from a techno-economic perspective, having a roundtrip exergy efficiency of 98.24%. Additionally, the paper presents a brief study on the effect of the frequency of the work-cycle, which serves as an introduction to the concept of optimizing a thermal storage system by splitting the load into multiple frequency components.
  • Preface to the special issue on electrochemical energy storage discussed
           at the NZEE conference 2017 in Czech Republic
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Petr Vanýsek
  • A novel low-cost and simple colloidal route for preparing high-performance
           carbon-coated LiFePO4 for lithium batteries
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Sana Dhaybi, Benoît Marsan, Amer Hammami Nanosized carbon-coated lithium iron phosphate (LiFePO4/C) particles were synthesized using a novel low-cost colloidal process with LiH2PO4, FeCl2 and anhydrous N-methylimidazole (NMI) as starting materials, following by a short annealing step at 600 °C. The ∼3–5 nm thick carbon coating comes from the carbonization of molten salt NMIH+Cl− derived from NMI; the resulting carbon contents of the LiFePO4/C powder is 2.53 wt.%. The materials were characterized by thermogravimetric and differential thermal analysis, differential scanning calorimetry, powder X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, atomic absorption spectroscopy, Raman spectroscopy, four-point probe method, cyclic voltammetry and galvanostatic cycling experiments in coin cells. The LiFePO4 phase reveals agglomeration of semi-spherically particles with an average individual size of 35 ± 4 nm. Carbon-coated LiFePO4 posseses electronic conductivity of 1.4 × 10−3 S cm−1 at room temperature causing a markable increase in rate capability. Cycling the cells between 2.2 and 4.2 V vs. Li+/Li resulted in a discharge capacity of 164 mAh g−1 at the first cycle of C/20 and 162 mA hg−1 after 35 cycles, which corresponds to over 95% of the theoretical capacity of olivine LiFePO4.
  • Preparation of α-MnO2/Ag/RGO hybrid films for asymmetric
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Shiqing Sun, Guohua Jiang, Yongkun Liu, Bo Yu, Uwamahoro Evariste The negative electrode materials are crucial to improve electrochemical performance in asymmetric supercapacitors (ASCs) as well as positive electrode. Herein, the α-MnO2/Ag/RGO hybrid films were prepared by a facile and rapid natural deposition technique and exhibit good electrochemical performance with specific capacitance of 804.6 F g−1 at 1 A g−1. The ASCs were further fabricated using NiCoS2/CNFs and α-MnO2/Ag/RGO film as positive and negative electrodes. The operation potential window of ASCs was 0–1.6 V. The fabricated ASCs exhibited the maximum energy density of 44.2 Wh kg−1 at a power density of 288.2 W kg−1. The as-fabricated ASCs has a great potential for application in portable and wearable energy-storage systems.
  • Demands on energy storage for renewable power sources
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Zdeněk Dostál, Libor Ladányi The article deals with the issue of energy storage facilities for renewable energy sources. Due to the ratio between power delivery and take-off, the energy storage system is a key element in these systems. It is useful to divide the energy storages into short, long and backup energy storage. Based on an analysis of the energy consumption of an apartment or habitable unit, it is possible to define the properties of each type of storage.
  • Experimental study on the cyclic behavior of thermal energy storage in an
           air-alumina packed bed
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Mohammad M.S. Al-Azawii, Carter Theade, Megan Danczyk, Erick Johnson, Ryan Anderson Thermal energy storage (TES) in a packed bed exemplifies important technology for concentrated solar thermal (CST) applications such as electricity production, desalination, enhanced oil recovery, fuel production and chemical processing. In this study, the cyclic charge-discharge behavior of packed bed TES was studied experimentally using alumina beads as packing material. Air was used as heat transfer fluid (HTF) with an inlet temperature of 150 °C. This paper shows the effect of flow rates, partial charge-discharge cycling, and storage hold time on the exergetic efficiencies. The results indicate that the exergy efficiency increases from 35.7% to 55.4% with increasing flow rate from 0.0020 to 0.0061 m3/s. The exergy decays for multiple cycles before reaching a steady state. Over partial charge-discharge cycles at flow rates of 0.0020, 0.0034, 0.0048, and 0.0061 m3/s, the exergetic efficiency decays from 59.8% to 50.2%, 72.5% to 61.2%, 79.0% to 66.2%, and 83.1% to 69.2%, respectively. Heat losses and axial thermal dispersion are two important variables that affect the exergy efficiency, and the individual contributions were estimated via a model for the partial cycles. Heat losses were considered for three durations of holding: no hold, 30 min hold and 120 min hold. The exergy efficiency decays from 53.2% to 31.0% from no hold to 120 min hold due to the heat lost to the ambient.
  • Examination of impact of lignosulfonates added to the negative active mass
           of a lead–acid battery electrode
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Jana Zimáková, Daniel Fryda, Sebastian Vaculík, Petr Bača, Marek Bouška We employed pasted negative electrodes of dimensions 55 × 20 × 7 mm placed between two pasted positive electrodes of the same dimensions separated with AGM separators of the type BG 260 EB 170 (1.7 mm in thickness). The negative paste was doped with 0.78 wt.% of milled CR2996 carbon (Maziva Týn Company, Czech Republic) and with different amounts of three types of organic lignosulfonates as expanders. The used expanders were commercial products Vanisperse A, Vanillex HW and Vanillex N (Borregaard LignoTech). After formation, the electrode packs were placed in custom cells with the usual H2SO4 electrolyte, designed to ensure application of defined pressure to the electrode system. Several conditioning cycles were performed, the excess electrolyte was then aspirated off and the cells were hermetically sealed. The initial capacity of the negative electrodes was around 3 Ah. The cells were then discharged to 50% of their capacity and subjected to partial-state of charge accelerated cycling by using symmetrical 25 s current pulses of 2.5 A followed by 3 s standing. The cells were cycled until their voltage dropped below 1.6 V. In each run, the cell voltage, the electrode potentials against a Cd electrode, and the applied pressure were measured after every 100 cycles. The performance of these electrodes was elevated by applying moderate compression of 4−2. Higher pressures are not recommended.Cells with higher amount of the added organic expander well tolerate deep cycling, and were able to regenerate better during the conditioning cycles between PSoC runs and its capacities have increased. The low-lignosulfonate-containing cells showed during the PSoC charging good charge acceptance at the beginning of the experiment, but with progression of time (PSoC runs), there was the most significant increase in polarization resistances and gradual degradation of NAM. Medium lignosulfonate cells exhibited the best properties throughout the PSoC runs. During the PSoC charging there is a good charge acceptance, low maximum voltage and stable polarization resistance.
  • Capacity matching of storage to PV in a global frame with different loads
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Peter D. Lund Adding much variable renewable energy production such as photovoltaics (PV) may cause severe mismatch between power supply and demand, which could constrain the use of PV as the main power option. Here we analyze the role of energy storage to compensate for the mismatch over a wide range of geographical sites and load types. The impact of PV-storage systems was mainly characterized through changes in the PV self-consumption (F). The sensitivity of PV-storage system sizing to costs and weather variations, and impacts to the remaining power system, were also considered. The main method used was energy balance simulation and a graphical method for PV-storage cost optimization. The main finding is that already a moderate amount of storage capacity could notably increase the utility of PV across all sites (26–60°N) and load types (from single household to regional/national load) studied. The optimal benefit is obtained with a net storage capacity of up to 2 kWh for each kWp of PV over all the loads and sites studied, when PV is sized equal to the yearly load. With a storage-to-PV ratio (r) of 2 WhWp−1, a PV-storage system could reach a self-consumption of 60–70% in a northern climate and 80–90% in a southern climate, respectively. The sensitivity of the optimum to yearly variations in solar insolation was minor. Targeting for a higher solar share would sharply increase the storage demand – covering all demand through PV requires up to two orders of magnitude more storage. The exact value of the optimum storage to PV array size strongly depends on the self-consumption target, costs, and site. With present storage cost levels and decreasing PV prices, oversizing PV over storage would be preferred to minimize the investment costs for a given self-consumption. With a typical PV-to-storage unit cost ratio (μ) of $500/kWh–$1200/kWp, the optimum for F = 70% is found at r ∼1 WhWp−1 for 42–60°N. The slope of the minimum cost is moderate, i.e. the sensitivity of the results to price changes in the vicinity of this minimum point is modest − halving the storage cost would affect the results by 10%. The analyses also indicate major impacts to the remaining energy system, which should deserve future attention. These findings help to better plan energy systems with PV.
  • Thermodynamic performance and cost optimization of a novel hybrid
           thermal-compressed air energy storage system design
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Sammy Houssainy, Mohammad Janbozorgi, Pirouz Kavehpour Compressed Air Energy Storage (CAES) can potentially allow renewable energy sources to meet electricity demands as reliably as coal-fired power plants. However, conventional CAES systems rely on the combustion of natural gas, require large storage volumes, and operate at high pressures, which possess inherent problems such as high costs, strict geological locations, and the production of greenhouse gas emissions. A novel and patented hybrid thermal-compressed air energy storage (HT-CAES) design is presented which allows a portion of the available energy, from the grid or renewable sources, to operate a compressor and the remainder to be converted and stored in the form of heat, through joule heating in a sensible thermal storage medium. The HT-CAES design incudes a turbocharger unit that provides supplementary mass flow rate alongside the air storage. The hybrid design and the addition of a turbocharger have the beneficial effect of mitigating the shortcomings of conventional CAES systems and its derivatives by eliminating combustion emissions and reducing storage volumes, operating pressures, and costs. Storage efficiency and cost are the two key factors, which upon integration with renewable energies would allow the sources to operate as independent forms of sustainable energy. The potential of the HT-CAES design is illustrated through a thermodynamic optimization study, which outlines key variables that have a major impact on the performance and economics of the storage system. The optimization analysis quantifies the required distribution of energy between thermal and compressed air energy storage, for maximum efficiency, and for minimum cost. This study provides a roundtrip energy and exergy efficiency map of the storage system and illustrates a trade off that exists between its capital cost and performance.
  • Metaheuristic methods applied to the pumps and turbines configuration
           design of water pumped storage systems
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): A. Setas Lopes, Rui Castro, Carlos Silva The increasing penetration of fluctuating Renewable Energy Sources (RES), particularly in small isolated power systems, is raising some problems in the operational management of the system. The simpler way to solve the problem is to perform RES curtailment, but this is not the right decision from an environmental point-of-view. In this context, the storage alternative is becoming more and more a cost-effective option. This paper presents an integrated techno-economic model, whose purpose is to come up with the optimal configuration of a Water Pumped Storage System (WPSS). The expected output is the WPSS design configuration, i.e. the pump number and size and turbine number and size, which leads to the maximum Net Present Value (NPV) of the investment project. To reach the proposed objective, the model uses meta-heuristic optimization techniques, namely Particle Swarm Optimization (PSO) and Genetic Algorithms (GA), with a Unit Commitment and Economic Dispatch module (UC + ED) of the thermal-based electrical generation units, in order to calculate the system operational costs. The Terceira Island, Azores archipelago, Portugal, is the case study presented as an application of the developed model. PSO and GA converge to the same results, pointing to an optimal WPSS configuration of 2 pumps of 490 kW and 1 turbine of 500 kW, with a 263 k€ positive NPV, therefore showing the economic and technical feasibility of a WPSS, in this application.
  • Battery durability and reliability under electric utility grid operations:
           Representative usage aging and calendar aging
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Matthieu Dubarry, Arnaud Devie Battery energy storage systems (BESS) are often viewed as solution to mitigate the intermittency of renewable energies in electric grids. However, battery degradation associated with grid-tied BESS usage has never been investigated in detail. This work was aimed at understanding the impact of a BESS representative usage profile on the degradation of commercial Li-ion cells. It was found that the cell temperature history had the strongest impact on battery degradation followed by the C-rate and the state of charge (SOC). Also, batteries lost capacity faster at low SOCs during calendar aging and under small SOC swings while cycling.Graphical abstractGraphical abstract for this article
  • Assessing the potential of an electric vehicle hybrid battery system
           comprising solid-state lithium metal polymer high energy and lithium-ion
           high power batteries
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Raphael Wegmann, Volker Döge, Dirk Uwe Sauer In this work the characterization and application of a prototype solid-state lithium metal battery for an electric vehicle application is addressed. This mid-temperature battery is operated at a temperature of 80 °C. In an innovative approach, this high energy technology is integrated into a hybrid battery system, where it is supported by a highest power lithium-titanate technology. Three hybrid battery system configurations are systematically derived for a high class vehicle with different performance requirements. On the basis of an overall vehicle simulation model, comprising a thermal model of the lithium metal polymer battery pack, the performance of the system is evaluated under regular and extreme driving conditions. The results indicate that battery hybridization makes a reasonable utilization of the lithium metal polymer battery in an electric vehicle possible. The power capability of the overall battery system in discharge as well as charge direction is significantly increased. Moreover, the system allows for a wider utilization of overall battery system's energy, resulting in an increase of drivable distance. Furthermore, additional functionalities of the hybrid battery system are discussed, such as warm-up procedure, low temperature performance enhancement and redundancy.
  • Survey of dilution or adsorption enthalpies of a series of hygroscopic
           sorption materials
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Thorge Brünig, Kristijan Krekić, Rudolf Pietschnig In order to assess the thermal behavior of water based sorption systems, isothermal titration calorimetry (ITC) experiments were done to measure the integral dilution enthalpies (ΔHD) of concentrated salt solutions via stepwise addition of water. Moreover the adsorption enthalpy (ΔHA) of different solids were measured with ITC as well. The data showing values of ΔHD in the range from 14 kJ/kg (KNO3) to −415 kJ/kg (NaOH) and ΔHA values from around 0.3 kJ/kg (MIL-53-AL) to −1380 kJ/kg (Zeolite XBF 13). Furthermore the titration results of the solid materials enable the possibility to calculate the adsorption capacity of these substances.
  • Humidity dependence of transport properties of composite materials used
           for thermochemical heat storage and thermal transformer appliances
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Pierre D’Ans, Oleksandr Skrylnyk, Wolfgang Hohenauer, Emilie Courbon, Loïc Malet, Marc Degrez, Gilbert Descy, Marc Frère Water sorption thermochemical heat storage is a promising way to provide dwellings with renewable central heating. It requires the use of several cubic meters of materials per dwelling. Depending on the design of the heating system, specific heat and mass transfer issues occur. For instance, the heat transfer rate in reactive medium and the kinetics of sorption process determine the system thermal power. In addition, the moisture propagation during inter-seasonal storage must be understood. In this paper, the influence of the water mass uptake on the apparent thermal conductivity and apparent mass diffusivity of solid material were studied. The studied material was a composite of calcium chloride (CaCl2) encapsulated in mesoporous silica with a salt content of 40–43 wt.%. The thermal conductivity was measured by the transient hot bridge method and varied from 0.13 to 0.16 W m−1 K−1, having a threshold at 0.14 g/g of water mass uptake. The apparent water mass diffusivity was studied using a diffusion column. The water diffusivity – concentration dependency was established by using the modified Hall method. The apparent diffusion coefficient ranged from 3 × 10−10 to 2 × 10−8 m2 s−1 in experimental conditions.
  • Irreversible calendar aging and quantification of the reversible capacity
           loss caused by anode overhang
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Meinert Lewerenz, Georg Fuchs, Lisa Becker, Dirk Uwe Sauer Calendar aging tests are presented quantifying the reversible capacity loss caused by lithium migration from the active part to the overhang of the anode. Based on these tests, capacity loss at five different SOCs with respect to the anode is evaluated. The remaining capacity shows a non-linear part in the beginning representing the reversible capacity loss caused by the overhang. The subsequent linear part ending after 100–200 days corresponds to the irreversible capacity loss. By extrapolating the linear part to t = 0, the lithium lost to the overhang is measureable for each storage condition. This approach matches well to theoretical values calculated using a simple equation. In later stages of the capacity loss curve, another superposed effect can be observed that decreases capacity fade. The reason is found in an increasing homogeneity of lithium distribution that correlates to the peak height of differential voltage characteristics. In this publication an increasing homogeneity is associated with a higher extractable capacity and vice versa. An especially high increase of homogeneity is observable when a high voltage difference coincides with pressure change due to lithium insertion. Finally, the temperature dependency of the lateral lithium flow is shown for three temperatures at a fixed storage position.Graphical abstractGraphical abstract for this article
  • Room temperature sodium-sulfur batteries as emerging energy source
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Deepak Kumar, Suman B. Kuhar, D.K. Kanchan This paper presents research and development on room temperature sodium-sulfur battery in the last decade. The review focuses on their electrochemical performance and recent trends in tailoring the electrode materials and electrolytes to enhance their performance by the researchers worldwide. Room temperature sodium-sulfur batteries seem to provide low-cost option for grid-scale energy storage and other electrochemical applications. The challenges encountered by these batteries are highlighted and remedies are also suggested in this review.Graphical abstractGraphical abstract for this article
  • How moisture content affects the performance of a liquid piston air
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Anirudh Srivatsa, Perry Y. Li For a compressed air energy storage (CAES) system to be competitive for the electrical grid, the air compressor/expander must be capable of high pressure, efficient and power dense. However, there is a trade-off between efficiency and power density mediated by heat transfer. This trade-off can be mitigated in a liquid (water) piston air-compressor/expander with enhanced heat transfer. However, in the past, dry air has been assumed in the design and analysis of the compression/expansion process. This paper investigates the effect of moisture on the compression efficiency and power. Evaporation and condensation of water play contradictory roles – while evaporation absorbs latent heat enhancing cooling, the tiny water droplets that form as water condenses also increase the apparent heat capacity. To investigate the effect of moisture, a 0-D numerical model that takes into account the water evaporation/condensation and water droplets has been developed, assuming equilibrium phase change. The 0-D model is also extended to a 1-D model to investigate the spatial effect. To increase computational efficiency, a uniform pressure in the 1-D deformable model is assumed. Results show that inclusion of moisture improves the efficiency-power trade-off minimally at lower flow rates, high efficiency cases, and more significantly at higher flow rates, lower efficiency cases. This effect is the same regardless of whether air is assumed to be an ideal gas or a real gas. The improvement is primarily attributed to the increase in apparent heat capacity due to the increased propensity of water to evaporate. While the 1-D model does capture the spatial effect, the 0-D model is found to be sufficiently accurate in predicting the efficiency and power density of the compressor.
  • Large scale electrical energy storage systems in India- current status and
           future prospects
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Shyam B, Kanakasabapathy P Backed by various promotional schemes and policies of the government, share of renewable energy sources (RES) is increasing in a faster way in India. Country has to promote the exploitation of renewable resources for a sustainable power system and economy. Increased penetration of intermittent RES affects the grid stability. Electrical Energy Storage (EES) systems are promising solution for grid stability issues. Different types of EES systems are developed all over the world and a number of storage technologies are under experimentation. This paper is mainly focusing on the status of the development and future prospects of large scale electrical energy storage systems in India. Significance of EES systems in modern power systems, overview of the existing large-scale EES systems, Comparison of large-scale EES systems and advantages and disadvantages of various storage technologies etc. are discussed in this paper. List of existing and developing large scale EES projects in India is introduced. Challenges in EES development in India and its significance in future are also studied.
  • Hollow porous FeF3·0.33H2O microspheres by AlPO4 coating as a cathode
           material of Na-ion batteries
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Min Liu, Xianyou Wang, Rui Zhang, Lei Liu, Hai Hu, Yu Wang, Shuangying Wei As the cathode material of Na-ion batteries based on conversion reaction, the iron-based fluorides have attracted ever-increasing attentions. Nevertheless, its poor electronic conductivity and side reactions usually lead to sluggish reaction kinetics and rapid capacity decay during cycling process, and thus limiting its practical application. Herein, a hollow porous FeF3·0.33H2O microsphere is successfully prepared via a solvothermal route and further modified with AlPO4. The results show that appropriate modification treatment can satisfactorily decrease charge-transfer resistance and enhance sodium diffusion rate. Compared with the pristine FeF3·0.33H2O, 4 wt.% AlPO4-coated sample shows a noticeable initial discharge capacity of 290 mAh g−1 in the range of 1.2–4.0 V, outstanding cycling stability (211 mAh g−1 after 80 cycles) and excellent rate capability (167 mAh g−1 at 2.0 C). The excellent electrochemical properties can be ascribed to the distinctively hierarchical mesoporous hollow structure of FeF3·0.33H2O, which facilitates electrolyte permeation and rapid ionic as well as electronic transmission. Besides, the multifunctional AlPO4 modification layer can improve the electronic conductivity, suppress the surface side reaction and buffer the volume changes during cycling processes, thus boosting the enhancement of the electrochemical performance. Therefore, this study offers a new strategy for improving and modifying the electrochemical performances of cathode materials for sodium-ion batteries.Graphical abstractGraphical abstract for this article
  • Thermodynamic analysis and optimisation of a combined liquid air and
           pumped thermal energy storage cycle
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Pau Farres-Antunez, Haobai Xue, Alexander J. White Pumped thermal energy storage (PTES) and liquid air energy storage (LAES) are two large-scale electricity storage technologies that store energy in the form of thermal exergy. This is achieved by operating mechanically-driven thermodynamic cycles between thermally insulated storage tanks. Both technologies are free from geographic restrictions that apply to pumped hydro and most compressed air storage. The present paper describes a novel, combined system in which PTES operates as a topping cycle and LAES as a bottoming cycle. The fundamental advantage is that the cold thermal reservoirs that would be required by the two separate cycles are replaced by a single heat exchanger that acts between them, thereby saving significant amounts of storage media per unit of energy stored. In order to reach cryogenic temperatures, the PTES cycle employs helium as the working fluid, while the LAES cycle uses supercritical air (at around 150 bar) which is cooled sufficiently to be fully liquefied upon expansion, thus avoiding recirculation of leftover vapour. A thermodynamic study of a baseline configuration of the combined cycle is presented and results are compared with those of the separate systems. These indicate that the new cycle has a similar round-trip efficiency to that of the separate systems while providing a significantly larger energy density. Furthermore, three adaptations of the base-case combined cycle are proposed and optimised. The best of these adaptations achieves an increase in thermodynamic efficiency of about 10 percent points (from 60% to 70%), therefore significantly exceeding the individual cycles in both energy density and efficiency.Graphical abstractGraphical abstract for this article
  • Hybrid DG-PV with groundwater pumped hydro storage for sustainable energy
           supply in arid areas
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Kanzumba Kusakana This paper discusses the development of a model for the optimal operation of a hybrid diesel-photovoltaic pumping system using, groundwater in a pumped hydro storage scheme which can be used to minimize the daily electricity cost of a farm. The developed model can minimize the power produced from the diesel generator, while optimally managing the generated power flow from the PV and the groundwater pumped hydro storage given the variable load demand as well as the availability of solar resource. As a case study, the model has been used to simulate a small farming activity in South Africa, with the aim of evaluating the potential energy cost saving achievable using the proposed system when compared to exclusive power production using a diesel generator. The simulation results show that a potential 71.3% of energy cost saving can be achieved using the proposed hybrid system with the optimal control model rather, than supplying the load demand by the diesel generator exclusively.
  • Capacitive effects in Li1−x Ni0.3Co0.3Mn0.3O2–Li x C y Li-ion cells
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Alexander U. Schmid, Lukas Lindel, Kai Peter Birke There are few publications about quantitative measurement of capacitance in Li-ion cells which in addition distinguish between pure electrostatic double-layer capacitance and capacitance caused by Faradaic effects. The measurement techniques electrochemical impedance spectroscopy, pulse current measurement and cyclic voltammetry are used to analyze a conventional high-energy Li-ion cell consisting of Li-nickel-manganese-cobalt-oxide Li1−xNi0.3Co0.3Mn0.3O2 as positive and graphite LixCy as negative electrode material. The results show the highest capacitance of the full cell at a frequency of 10 mHz at approximately 40% state-of-charge (SOC), which is equal to the cell voltage around 3.64 V, attributed to intercalation capacitance. Toward higher frequencies around 1 Hz, the capacitance increases with SOC. The measurements reveal that the positive electrode mainly causes this sensitivity of capacitance on SOC or electrode potential at around 1 Hz.
  • Construction and characterizations of hollow carbon
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Qun Lu, Jia Liu, Xianyou Wang, Bing Lu, Manfang Chen, Meihong Liu The hollow carbon microsphere@polypyrrole (HCS@PPy) composite has been designed, synthesized through in situ chemical oxidation polymerization, and used as the active electrode material of supercapacitor. The porous structure, morphology and supercapacitive behaviors of the HCS@PPy composite are investigated by various physical characterization techniques and electrochemical measurement. The results show that HCS has the lychee-like hollow spherical morphology, and a fluffy PPy thin layer with thickness of 13 nm is uniformly coated on the surface of the HCS. The HCS@PPy composite reveals a high specific capacitance of 508 F/g at 1 A/g since it is the combination of both double-layer capacitances of HCS and faradic capacitance of PPy. The supercapacitor using HCS@PPy composite as the active material delivers excellent rate performance and outstanding cycle stability. Furthermore, the asymmetrical supercapacitor based on the HCS@PPy composite shows a high energy density of 46 Wh/kg at the power density of 350 W/kg. The improved supercapacitive performance is closely related with the integrated advantage of unique hollow porous structure of HCS and faradaic redox behavior of PPy, indicating that the design and preparation of HCS@PPy composite is a promising strategy for active material of high performance supercapacitor.Graphical abstractPreparation and characterization of the hollow carbon microsphere@polypyrrole (HCS@PPy) composite via chemical oxidation polymerization for the supercapacitors.Graphical abstract for this article
  • Estimating available salt volume for potential CAES development: A case
           study using the Northwich Halite of the Cheshire Basin
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): D. Parkes, D.J. Evans, P. Williamson, J.D.O. Williams The massively bedded rock salts forming the Northwich Halite Member of the Cheshire Basin represent a huge mineral resource, which historically, have been worked by dry mining for rock salt and brine production from both the area of wet rockhead and also from solution-mined caverns. More recently, the halite beds have also provided the host storage horizon for natural gas storage in specifically designed and constructed solution-mined salt caverns. Increasingly, compressed air energy storage (CAES) is being viewed as a viable bulk storage option for surplus electrical energy, which may be through the use of off-peak electricity from both conventional and renewable sources. We describe a novel technique using Esri’s ArcGIS® Geographic Information System software, to derive potential storage cavern locations and an estimate of the physical volumes that might be available for storage purposes, including for CAES. The process involves defining the spatial distribution, thickness and insoluble content of the halite beds is described, together with an estimate of the potential physical volumes of solution-mined caverns. Cavern volumes compare favourably with those of current gas storage facilities, which are illustrated in terms of their surface footprints and use of resource.
  • A high frequency model for predicting the behavior of lithium-ion
           batteries connected to fast switching power electronics
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Pablo Korth Pereira Ferraz, Robert Schmidt, Delf Kober, Julia Kowal Battery powered energy systems such as electric vehicles utilize power electronics for controlling energy flows between the battery and the load or generation, respectively. Therefore, the battery is under high frequency stress due to fast switching power electronic devices. However, most battery models throughout the literature are not able to cope with high frequency excitation. This paper proposes an easy to implement equivalent circuit model that covers aforementioned frequency regions with a series of inductors that are each connected in parallel with an ohmic resistance. This circuit is parameterized by electrochemical impedance spectroscopy (EIS) up to 100 kHz. For further regions that reach regions of megahertz a skin effect model is investigated and compared to the RL-model. It is shown that such semi-empirical models can be motivated by geometrical considerations that can be found in the literature. Moreover, the proposed model is validated by simulating the voltage response from an input current that originates from an actual back-to-back half bridge DC/DC converter. The promising results indicate that such models might be implemented in future battery energy systems to improve insights on how batteries react to perturbations such as EMI noise or high frequency current ripple.
  • Detecting the internal short circuit in large-format lithium-ion battery
           using model-based fault-diagnosis algorithm
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Xuning Feng, Yue Pan, Xiangming He, Li Wang, Minggao Ouyang The spontaneous internal short circuit that sporadically occurs during operation is an unsolved safety problem that hinders the widespread application of lithium ion batteries. An online fault-diagnosis algorithm is an urgent requirement for early detection of the spontaneous internal short circuit of lithium-ion batteries to guarantee safe operation. This paper presents a model-based fault-diagnosis algorithm for online internal-short-circuit detection. Relying on the theory of model-based control, the algorithm transforms the measured voltage and temperature to the intrinsic electrochemical status that can reflect typical internal-short-circuit features, i.e. the excessive depletion of capacity and abnormal heat generation. The estimated status of the suspicious cell deviates from the average value of the battery pack, therefore the algorithm can capture the internal-short-circuit fault by evaluating the levels of deviation. Simultaneously considering the diagnosis result calculated from both the voltage and temperature signal helps enhance the robustness of the algorithm with few false alarms. Substitute internal-short-circuit tests confirm that the algorithm is capable of identifying the internal-short-circuit fault before it develops into a severe hazard, e.g., thermal runaway. The equivalent short resistance, which can reflect the level of the internal short circuit, can be estimated with small error by the online fault-diagnosis algorithm.
  • A two-dimensional porous electrode model for designing pore structure in a
           quinone-based flow cell
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Chengwei Ma, Xin Li, Luyin Lin, Liangliang Chen, Min Wang, Jiangqi Zhou A two-dimensional porous electrode model for designing a pore structure in a quinone-based flow battery was developed and validated by using experimental data from a metal-free quinone-based flow battery. The effects of porosity and pore size distribution on electrode performance and concentration fields were analyzed, the appropriate porosity and pore size distribution were obtained. In addition, the comprehensive effect of pore volume, specific surface area and pore size were considered, the dimensionless number shape factor SF was introduced to characterize the morphology, and the effect of morphology on the electrode performance was also investigated. This model was expected to understand the effect of morphology on the electrode performance and guide the preparation of the electrode. Extensions to the model in actual tests and future work were suggested.
  • Optimal energy storage sizing using equivalent circuit modelling for
           prosumer applications (Part II)
    • Abstract: Publication date: August 2018Source: Journal of Energy Storage, Volume 18Author(s): Cong-Toan Pham, Daniel Månsson An optimal system design indirectly implies efficient use of available resources, i.e., minimum investment to achieve the desired outcome. An increased demand of energy storages highlights the importance of efficient use and optimal storage sizing. However, the variety of available and newly developed storage technologies complicates decision-making in choosing the appropriate technology to the compatible application. The characterization of storage types extends to the inherent dynamic behavior and technical limitations, which is imperative for storage system design. This paper proposes a brute-force method of optimal storage system sizing based on the equivalent circuit modeling while considering storage's operation constraints. The sizing routine is applied to a set of different energy storage technologies (lead-acid, Li-ion, vanadium-redox flow battery, double-layer capacitor, flywheel) to balance the energy demand of a single-family building supported by a 3.36 kWpeak photovoltaic system. This case focuses on the energy management application of energy storages. Additionally, a suitability index is introduced to determine the applicability of the investigated storages in reference to an ideal case.
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