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Special Issue "Electrochemical Energy Storage—Battery and Capacitor"

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A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: closed (15 August 2014)

Special Issue Editor

Guest Editor
Dr. Sheng S. Zhang (Website)

Sensors and Electron Devices Directorate, RDRL-SED-C, U.S. Army Research Laboratory, Adelphi, MD 20783, USA
Interests: lithium-ion batteries; beyond lithium-ion batteries; metal-air batteries; electrochemical capacitors

Special Issue Information

Dear Colleagues,

This Special Issue is the continuation of the previous Special Issue “Li-ion Batteries and Energy Storage Devices” in 2013. In this Special Issue, we extend the scope to all electrochemical energy storage systems, including batteries, electrochemical capacitors, and their combinations. Batteries cover all types of primary or secondary batteries, metal-air batteries, and redox flow batteries, and electrochemical capacitors include double-layer capacitors and pseudocapacitors. This Special Issue addresses the current and future advancement in all aspects of the science, technology, engineering and applications of electrochemical energy storage systems.

We invite research and review articles on a wide range of subjects within materials science and engineering, nanotechnology, physics, chemistry, electrochemistry. Manuscripts on the testing methods, simulations, electric or thermal management of single cells or battery packs as well as on the applications and recycling technologies of electrochemical energy storage devices are also in the scope of this Special Issue.

Dr. Sheng S. Zhang
Guest Editor

Submission

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. Papers will be published continuously (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are refereed through a peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed Open Access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1400 CHF (Swiss Francs).


Keywords

  • energy storage
  • rechargeable battery
  • lithium-ion battery
  • lithium battery
  • capacitor

Published Papers (19 papers)

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Open AccessArticle Theoretical Exploration of Various Lithium Peroxide Crystal Structures in a Li-Air Battery
Energies 2015, 8(1), 529-548; doi:10.3390/en8010529
Received: 11 November 2014 / Accepted: 6 January 2015 / Published: 14 January 2015
Cited by 5 | PDF Full-text (2149 KB) | HTML Full-text | XML Full-text
Abstract
We describe a series of metastable Li2O2 crystal structures involving different orientations and displacements of the O22− peroxy ions based on the known Li2O2 crystal structure. Within the vicinity of the chemical potential ΔG [...] Read more.
We describe a series of metastable Li2O2 crystal structures involving different orientations and displacements of the O22− peroxy ions based on the known Li2O2 crystal structure. Within the vicinity of the chemical potential ΔG ~ 0.20 eV/Li from the thermodynamic ground state of the Li2O2 crystal structure (i.e., Föppl structure), all of these newly found metastable Li2O2 crystal structures are found to be insulating and high-k materials, and they have a common unique signature of an O22− O-O vibration mode (ω ~ 799–865 cm−1), which is in the range of that commonly observed in Li-air battery experiments, regardless of the random O22− orientations and the symmetry in the crystal lattice. From XRD patterns analysis, the commercially available Li2O2 powder is confirmed to be the thermodynamic ground state Föppl-like structure. However, for Li2O2 compounds that are grown electrochemically under the environment of Li-O2 cells, we found that the XRD patterns alone are not sufficient for structural identification of these metastable Li2O2 crystalline phases due to the poor crystallinity of the sample. In addition, the commonly known Raman signal of O22− vibration mode is also found to be insufficient to validate the possible existence of these newly predicted Li2O2 crystal structures, as all of them similarly share the similar O22− vibration mode. However considering that the discharge voltage in most Li-O2 cells are typically several tenths of an eV below the thermodynamic equilibrium for the formation of ground state Föppl structure, the formation of these metastable Li2O2 crystal structures appears to be thermodynamically feasible. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle Modeling of the Electrical and Thermal Behaviors of an Ultracapacitor
Energies 2014, 7(12), 8264-8278; doi:10.3390/en7128264
Received: 21 August 2014 / Revised: 26 November 2014 / Accepted: 27 November 2014 / Published: 10 December 2014
Cited by 1 | PDF Full-text (1059 KB) | HTML Full-text | XML Full-text
Abstract
This paper reports a modeling methodology to predict the electrical and thermal behaviors of a 2.7 V/650 F ultracapacitor (UC) cell from LS Mtron Ltd. (Anyang, Korea). The UC cell is subject to the charge/discharge cycling with constant-current between 1.35 V and [...] Read more.
This paper reports a modeling methodology to predict the electrical and thermal behaviors of a 2.7 V/650 F ultracapacitor (UC) cell from LS Mtron Ltd. (Anyang, Korea). The UC cell is subject to the charge/discharge cycling with constant-current between 1.35 V and 2.7 V. The charge/discharge current values examined are 50, 100, 150, and 200 A. A three resistor-capacitor (RC) parallel branch model is employed to calculate the electrical behavior of the UC. The modeling results for the variations of the UC cell voltage as a function of time for various charge/discharge currents are in good agreement with the experimental measurements. A three-dimensional thermal model is presented to predict the thermal behavior of the UC. Both of the irreversible and reversible heat generations inside the UC cell are considered. The validation of the three-dimensional thermal model is provided through the comparison of the modeling results with the experimental infrared (IR) image at various charge/discharge currents. A zero-dimensional thermal model is proposed to reduce the significant computational burden required for the three-dimensional thermal model. The zero-dimensional thermal model appears to generate the numerical results accurate enough to resolve the thermal management issues related to the UC for automotive applications without relying on significant computing resources. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle Improved Control Strategy for Microgrid Ultracapacitor Energy Storage Systems
Energies 2014, 7(12), 8095-8115; doi:10.3390/en7128095
Received: 3 October 2014 / Revised: 4 November 2014 / Accepted: 18 November 2014 / Published: 2 December 2014
Cited by 4 | PDF Full-text (1713 KB) | HTML Full-text | XML Full-text
Abstract
Ultracapacitors (UCs), with their features of high power density and high current charge-discharge, have become the best choice for dynamic power compensation to improve the stability of microgrids and are increasingly being applied in microgrids. This paper presents the control of an [...] Read more.
Ultracapacitors (UCs), with their features of high power density and high current charge-discharge, have become the best choice for dynamic power compensation to improve the stability of microgrids and are increasingly being applied in microgrids. This paper presents the control of an energy storage system (ESS) based on ultracapacitors in the context of grid-connected microgrids. The ESS is composed of DC/AC and DC/DC converters tied by a dc link. An improved dynamic model for the ESS is proposed. Based on the proposed model a Proportional-Integral-Resonant (PIR) DC link voltage controller is proposed to maintain the DC link voltage through the charging-discharging control of ultracapacitors, capable of working properly under all operating conditions. An extra double frequency component is injected into the UC current by a R controller to dynamically compensate for DC instantaneous power and double frequency AC instantaneous power due to unbalanced grid conditions and disturbances. This feature maintains the DC link voltage constant under unbalanced conditions and increases the degrees of freedom of the DC/AC converter and thus facilitates the application of UCs in microgrids. Simulation and experimental results verify the effectiveness of the proposed control strategy. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle Three-Dimensional Modeling of the Thermal Behavior of a Lithium-Ion Battery Module for Hybrid Electric Vehicle Applications
Energies 2014, 7(11), 7586-7601; doi:10.3390/en7117586
Received: 29 August 2014 / Revised: 6 November 2014 / Accepted: 11 November 2014 / Published: 18 November 2014
Cited by 3 | PDF Full-text (1762 KB) | HTML Full-text | XML Full-text
Abstract
This paper reports a modeling methodology to predict the effects of operating conditions on the thermal behavior of a lithium-ion battery (LIB) module. The potential and current density distributions on the electrodes of an LIB cell are predicted as a function of [...] Read more.
This paper reports a modeling methodology to predict the effects of operating conditions on the thermal behavior of a lithium-ion battery (LIB) module. The potential and current density distributions on the electrodes of an LIB cell are predicted as a function of discharge time based on the principle of charge conservation. By using the modeling results of the potential and current density distributions of the LIB cell, the non-uniform distribution of the heat generation rate in a single LIB cell within the module is calculated. Based on the heat generation rate in the single LIB cell determined as a function of the position on the electrode and time, a three-dimensional thermal modeling of an LIB module is performed to calculate the three-dimensional velocity, pressure, and temperature distributions within the LIB module as a function of time at various operating conditions. Thermal modeling of an LIB module is validated by the comparison between the experimental measurements and the modeling results. The effect of the cooling condition of the LIB module on the temperature rise of the LIB cells within the module and the uniformity of the distribution of the cell temperatures are analyzed quantitatively based on the modeling results. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle Study on the Optimal Charging Strategy for Lithium-Ion Batteries Used in Electric Vehicles
Energies 2014, 7(10), 6783-6797; doi:10.3390/en7106783
Received: 29 August 2014 / Revised: 25 September 2014 / Accepted: 17 October 2014 / Published: 21 October 2014
Cited by 7 | PDF Full-text (457 KB) | HTML Full-text | XML Full-text
Abstract
The charging method of lithium-ion batteries used in electric vehicles (EVs) significantly affects its commercial application. This paper aims to make three contributions to the existing literature. (1) In order to achieve an efficient charging strategy for lithium-ion batteries with shorter charging [...] Read more.
The charging method of lithium-ion batteries used in electric vehicles (EVs) significantly affects its commercial application. This paper aims to make three contributions to the existing literature. (1) In order to achieve an efficient charging strategy for lithium-ion batteries with shorter charging time and lower charring loss, the trade-off problem between charging loss and charging time has been analyzed in details through the dynamic programing (DP) optimization algorithm; (2) To reduce the computation time consumed during the optimization process, we have proposed a database based optimization approach. After off-line calculation, the simulation results can be applied to on-line charge; (3) The novel database-based DP method is proposed and the simulation results illustrate that this method can effectively find the suboptimal charging strategies under a certain balance between the charging loss and charging time. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
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Open AccessArticle Prognostics of Lithium-Ion Batteries Based on Battery Performance Analysis and Flexible Support Vector Regression
Energies 2014, 7(10), 6492-6508; doi:10.3390/en7106492
Received: 31 July 2014 / Revised: 9 September 2014 / Accepted: 25 September 2014 / Published: 10 October 2014
Cited by 5 | PDF Full-text (2457 KB) | HTML Full-text | XML Full-text
Abstract
Accurate prediction of the remaining useful life (RUL) of lithium-ion batteries is important for battery management systems. Traditional empirical data-driven approaches for RUL prediction usually require multidimensional physical characteristics including the current, voltage, usage duration, battery temperature, and ambient temperature. [...] Read more.
Accurate prediction of the remaining useful life (RUL) of lithium-ion batteries is important for battery management systems. Traditional empirical data-driven approaches for RUL prediction usually require multidimensional physical characteristics including the current, voltage, usage duration, battery temperature, and ambient temperature. From a capacity fading analysis of lithium-ion batteries, it is found that the energy efficiency and battery working temperature are closely related to the capacity degradation, which account for all performance metrics of lithium-ion batteries with regard to the RUL and the relationships between some performance metrics. Thus, we devise a non-iterative prediction model based on flexible support vector regression (F-SVR) and an iterative multi-step prediction model based on support vector regression (SVR) using the energy efficiency and battery working temperature as input physical characteristics. The experimental results show that the proposed prognostic models have high prediction accuracy by using fewer dimensions for the input data than the traditional empirical models. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle An Improved Genetic Algorithm for Optimal Stationary Energy Storage System Locating and Sizing
Energies 2014, 7(10), 6434-6458; doi:10.3390/en7106434
Received: 3 July 2014 / Revised: 11 August 2014 / Accepted: 19 September 2014 / Published: 9 October 2014
Cited by 9 | PDF Full-text (996 KB) | HTML Full-text | XML Full-text
Abstract
The application of a stationary ultra-capacitor energy storage system (ESS) in urban rail transit allows for the recuperation of vehicle braking energy for increasing energy savings as well as for a better vehicle voltage profile. This paper aims to obtain the best [...] Read more.
The application of a stationary ultra-capacitor energy storage system (ESS) in urban rail transit allows for the recuperation of vehicle braking energy for increasing energy savings as well as for a better vehicle voltage profile. This paper aims to obtain the best energy savings and voltage profile by optimizing the location and size of ultra-capacitors. This paper firstly raises the optimization objective functions from the perspectives of energy savings, regenerative braking cancellation and installation cost, respectively. Then, proper mathematical models of the DC (direct current) traction power supply system are established to simulate the electrical load-flow of the traction supply network, and the optimization objections are evaluated in the example of a Chinese metro line. Ultimately, a methodology for optimal ultra-capacitor energy storage system locating and sizing is put forward based on the improved genetic algorithm. The optimized result shows that certain preferable and compromised schemes of ESSs’ location and size can be obtained, acting as a compromise between satisfying better energy savings, voltage profile and lower installation cost. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle Non-Destructive Analysis of Degradation Mechanisms in Cycle-Aged Graphite/LiCoO2 Batteries
Energies 2014, 7(10), 6282-6305; doi:10.3390/en7106282
Received: 25 July 2014 / Revised: 13 September 2014 / Accepted: 23 September 2014 / Published: 29 September 2014
Cited by 5 | PDF Full-text (1786 KB) | HTML Full-text | XML Full-text
Abstract
Non-destructive analysis of degradation mechanisms can be very beneficial for the prognostics and health management (PHM) study of lithium-ion batteries. In this paper, a type of graphite/LiCoO2 battery was cycle aged at high ambient temperature, then 25 parameters of the multi-physics [...] Read more.
Non-destructive analysis of degradation mechanisms can be very beneficial for the prognostics and health management (PHM) study of lithium-ion batteries. In this paper, a type of graphite/LiCoO2 battery was cycle aged at high ambient temperature, then 25 parameters of the multi-physics model were identified. Nine key parameters degraded with the cycle life, and they were treated as indicators of battery degradation. Accordingly, the degradation mechanism was discussed by using the multi-physics model and key parameters, and the reasons for capacity fade and the internal resistance increase were analyzed in detail. All evidence indicates that the formation reaction of the solid electrolyte interface (SEI) film is the main cause of battery degradation at high ambient temperature. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle Determining the Limiting Current Density of Vanadium Redox Flow Batteries
Energies 2014, 7(9), 5863-5873; doi:10.3390/en7095863
Received: 2 July 2014 / Revised: 18 August 2014 / Accepted: 27 August 2014 / Published: 5 September 2014
Cited by 2 | PDF Full-text (489 KB) | HTML Full-text | XML Full-text
Abstract
All-vanadium redox flow batteries (VRFBs) are used as energy storage systems for intermittent renewable power sources. The performance of VRFBs depends on materials of key components and operating conditions, such as current density, electrolyte flow rate and electrolyte composition. Mass transfer overpotential [...] Read more.
All-vanadium redox flow batteries (VRFBs) are used as energy storage systems for intermittent renewable power sources. The performance of VRFBs depends on materials of key components and operating conditions, such as current density, electrolyte flow rate and electrolyte composition. Mass transfer overpotential is affected by the electrolyte flow rate and electrolyte composition, which is related to the limiting current density. In order to investigate the effect of operating conditions on mass transport overpotential, this study established a relationship between the limiting current density and operating conditions. First, electrolyte solutions with different states of charge were prepared and used for a single cell to obtain discharging polarization curves under various operating conditions. The experimental results were then analyzed and are discussed in this paper. Finally, this paper proposes a limiting current density as a function of operating conditions. The result helps predict the effect of operating condition on the cell performance in a mathematical model. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
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Open AccessArticle An Acausal Li-Ion Battery Pack Model for Automotive Applications
Energies 2014, 7(9), 5675-5700; doi:10.3390/en7095675
Received: 24 July 2014 / Revised: 13 August 2014 / Accepted: 19 August 2014 / Published: 28 August 2014
Cited by 8 | PDF Full-text (3031 KB) | HTML Full-text | XML Full-text
Abstract
In this work, a novel acausal and reconfigurable battery pack model is presented. The model structure adopted for the battery cell is based on an equivalent circuit representation. The circuit elements are modified to take account of both hysteresis and diffusion limitation. [...] Read more.
In this work, a novel acausal and reconfigurable battery pack model is presented. The model structure adopted for the battery cell is based on an equivalent circuit representation. The circuit elements are modified to take account of both hysteresis and diffusion limitation. The latter is known to be a nonlinear function of large operating currents or long operating times. It is shown that the integration of a current dependent time constant within the cell model better emulates the solid diffusional dynamics of lithium intercalation into the active material under large electrical loads. The advantages of an acausal modeling approach, when scaling-up individual cell models into a complete battery system are also presented. Particular consideration is given to emulating the impact of cell to cell variations on pack performance. Using statistical analysis of battery tests, cell model parameter variations are characterized and quantified. The cell and scaled-up pack model are parameterized for a number of commercially available cell formats, energy capacities and chemistries. The new models are validated using transient, real-world, electrical data measured from an electric vehicle (EV) operating within an urban environment. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle Evaluation of Model Based State of Charge Estimation Methods for Lithium-Ion Batteries
Energies 2014, 7(8), 5065-5082; doi:10.3390/en7085065
Received: 16 April 2014 / Revised: 1 August 2014 / Accepted: 5 August 2014 / Published: 8 August 2014
Cited by 12 | PDF Full-text (810 KB) | XML Full-text
Abstract
Four model-based State of Charge (SOC) estimation methods for lithium-ion (Li-ion) batteries are studied and evaluated in this paper. Different from existing literatures, this work evaluates different aspects of the SOC estimation, such as the estimation error distribution, the estimation rise time, [...] Read more.
Four model-based State of Charge (SOC) estimation methods for lithium-ion (Li-ion) batteries are studied and evaluated in this paper. Different from existing literatures, this work evaluates different aspects of the SOC estimation, such as the estimation error distribution, the estimation rise time, the estimation time consumption, etc. The equivalent model of the battery is introduced and the state function of the model is deduced. The four model-based SOC estimation methods are analyzed first. Simulations and experiments are then established to evaluate the four methods. The urban dynamometer driving schedule (UDDS) current profiles are applied to simulate the drive situations of an electrified vehicle, and a genetic algorithm is utilized to identify the model parameters to find the optimal parameters of the model of the Li-ion battery. The simulations with and without disturbance are carried out and the results are analyzed. A battery test workbench is established and a Li-ion battery is applied to test the hardware in a loop experiment. Experimental results are plotted and analyzed according to the four aspects to evaluate the four model-based SOC estimation methods. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
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Open AccessArticle Cycle Life of Commercial Lithium-Ion Batteries with Lithium Titanium Oxide Anodes in Electric Vehicles
Energies 2014, 7(8), 4895-4909; doi:10.3390/en7084895
Received: 24 June 2014 / Revised: 20 July 2014 / Accepted: 22 July 2014 / Published: 30 July 2014
Cited by 12 | PDF Full-text (756 KB) | HTML Full-text | XML Full-text
Abstract
The lithium titanium oxide (LTO) anode is widely accepted as one of the best anodes for the future lithium ion batteries in electric vehicles (EVs), especially since its cycle life is very long. In this paper, three different commercial LTO cells from [...] Read more.
The lithium titanium oxide (LTO) anode is widely accepted as one of the best anodes for the future lithium ion batteries in electric vehicles (EVs), especially since its cycle life is very long. In this paper, three different commercial LTO cells from different manufacturers were studied in accelerated cycle life tests and their capacity fades were compared. The result indicates that under 55 °C, the LTO battery still shows a high capacity fade rate. The battery aging processes of all the commercial LTO cells clearly include two stages. Using the incremental capacity (IC) analysis, it could be judged that in the first stage, the battery capacity decreases mainly due to the loss of anode material and the degradation rate is lower. In the second stage, the battery capacity decreases much faster, mainly due to the degradation of the cathode material. The result is important for the state of health (SOH) estimation and remaining useful life (RUL) prediction of battery management system (BMS) for LTO batteries in EVs. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle Proof-of-Concept of a Zinc-Silver Battery for the Extraction of Energy from a Concentration Difference
Energies 2014, 7(6), 3664-3683; doi:10.3390/en7063664
Received: 24 April 2014 / Revised: 5 June 2014 / Accepted: 9 June 2014 / Published: 13 June 2014
Cited by 9 | PDF Full-text (238 KB) | HTML Full-text | XML Full-text | Correction
Abstract
The conversion of heat into current can be obtained by a process with two stages. In the first one, the heat is used for distilling a solution and obtaining two flows with different concentrations. In the second stage, the two flows are [...] Read more.
The conversion of heat into current can be obtained by a process with two stages. In the first one, the heat is used for distilling a solution and obtaining two flows with different concentrations. In the second stage, the two flows are sent to an electrochemical cell that produces current by consuming the concentration difference. In this paper, we propose such an electrochemical cell, working with water solutions of zinc chloride. The cell contains two electrodes, made respectively of zinc and silver covered by silver chloride. The operation of the cell is analogous to that of the capacitive mixing and of the “mixing entropy battery”: the electrodes are charged while dipped in the concentrated solution and discharged when dipped in the diluted solution. The cyclic operation allows us to extract a surplus of energy, at the expense of the free energy of the concentration difference. We evaluate the feasibility of such a cell for practical applications and find that a power up to 2 W per m2 of the surface of the electrodes can be achieved. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
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Open AccessArticle A Combined State of Charge Estimation Method for Lithium-Ion Batteries Used in a Wide Ambient Temperature Range
Energies 2014, 7(5), 3004-3032; doi:10.3390/en7053004
Received: 5 March 2014 / Revised: 11 April 2014 / Accepted: 25 April 2014 / Published: 2 May 2014
Cited by 7 | PDF Full-text (3155 KB) | HTML Full-text | XML Full-text
Abstract
Ambient temperature is a significant factor that influences the characteristics of lithium-ion batteries, which can produce adverse effects on state of charge (SOC) estimation. In this paper, an integrated SOC algorithm that combines an advanced ampere-hour counting (Adv Ah) method and multistate [...] Read more.
Ambient temperature is a significant factor that influences the characteristics of lithium-ion batteries, which can produce adverse effects on state of charge (SOC) estimation. In this paper, an integrated SOC algorithm that combines an advanced ampere-hour counting (Adv Ah) method and multistate open-circuit voltage (multi OCV) method, denoted as “Adv Ah + multi OCV”, is proposed. Ah counting is a simple and general method for estimating SOC. However, the available capacity and coulombic efficiency in this method are influenced by the operating states of batteries, such as temperature and current, thereby causing SOC estimation errors. To address this problem, an enhanced Ah counting method that can alter the available capacity and coulombic efficiency according to temperature is proposed during the SOC calculation. Moreover, the battery SOCs between different temperatures can be mutually converted in accordance with the capacity loss. To compensate for the accumulating errors in Ah counting caused by the low precision of current sensors and lack of accurate initial SOC, the OCV method is used for calibration and as a complement. Given the variation of available capacities at different temperatures, rated/non-rated OCV–SOCs are established to estimate the initial SOCs in accordance with the Ah counting SOCs. Two dynamic tests, namely, constant- and alternated-temperature tests, are employed to verify the combined method at different temperatures. The results indicate that our method can provide effective and accurate SOC estimation at different ambient temperatures. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle A New Topology and Control Strategy for a Hybrid Battery-Ultracapacitor Energy Storage System
Energies 2014, 7(5), 2874-2896; doi:10.3390/en7052874
Received: 5 March 2014 / Revised: 8 April 2014 / Accepted: 10 April 2014 / Published: 29 April 2014
Cited by 12 | PDF Full-text (479 KB) | HTML Full-text | XML Full-text
Abstract
This study investigates a new hybrid energy storage system (HESS), which consists of a battery bank and an ultra-capacitor (UC) bank, and a control strategy for this system. The proposed topology uses a bi-directional DC-DC converter with a lower power rating than [...] Read more.
This study investigates a new hybrid energy storage system (HESS), which consists of a battery bank and an ultra-capacitor (UC) bank, and a control strategy for this system. The proposed topology uses a bi-directional DC-DC converter with a lower power rating than those used in the traditional HESS topology. The proposed HESS has four operating modes, and the proposed control strategy chooses the appropriate operating mode and regulates the distribution of power between the battery bank and the UC bank. Additionally, the control system prevents surges during mode switching and ensures that both the battery bank and the bi-directional DC-DC converter operate within their power limits. The proposed HESS is used to improve the performance of an existing power-split hybrid electric vehicle (HEV). A method for calculating the parameters of the proposed HESS is presented. A simulation model of the proposed HESS and control strategy was developed, and a scaled-down experimental platform was constructed. The results of the simulations and the experiments provide strong evidence for the feasibility of the proposed topology and the control strategy. The performance of the HESS is not influenced by the power limits of the bi-directional DC-DC converter. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle Battery Management System—Balancing Modularization Based on a Single Switched Capacitor and Bi-Directional DC/DC Converter with the Auxiliary Battery
Energies 2014, 7(5), 2897-2937; doi:10.3390/en7052897
Received: 27 March 2014 / Revised: 16 April 2014 / Accepted: 17 April 2014 / Published: 29 April 2014
Cited by 7 | PDF Full-text (2141 KB) | HTML Full-text | XML Full-text
Abstract
Lithium-based batteries are considered as the most advanced batteries technology, which can be designed for high energy or high power storage systems. However, the battery cells are never fully identical due to the fabrication process, surrounding environment factors and differences between the [...] Read more.
Lithium-based batteries are considered as the most advanced batteries technology, which can be designed for high energy or high power storage systems. However, the battery cells are never fully identical due to the fabrication process, surrounding environment factors and differences between the cells tend to grow if no measures are taken. In order to have a high performance battery system, the battery cells should be continuously balanced for maintain the variation between the cells as small as possible. Without an appropriate balancing system, the individual cell voltages will differ over time and battery system capacity will decrease quickly. These issues will limit the electric range of the electric vehicle (EV) and some cells will undergo higher stress, whereby the cycle life of these cells will be shorter. Quite a lot of cell balancing/equalization topologies have been previously proposed. These balancing topologies can be categorized into passive and active balancing. Active topologies are categorized according to the active element used for storing the energy such as capacitor and/or inductive component as well as controlling switches or converters. This paper proposes an intelligent battery management system (BMS) including a battery pack charging and discharging control with a battery pack thermal management system. The BMS user input/output interfacing. The battery balancing system is based on battery pack modularization architecture. The proposed modularized balancing system has different equalization systems that operate inside and outside the modules. Innovative single switched capacitor (SSC) control strategy is proposed to balance between the battery cells in the module (inside module balancing, IMB). Novel utilization of isolated bidirectional DC/DC converter (IBC) is proposed to balance between the modules with the aid of the EV auxiliary battery (AB). Finally an experimental step-up has been implemented for the validation of the proposed balancing system. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessArticle Geometric Characteristics of Three Dimensional Reconstructed Anode Electrodes of Lithium Ion Batteries
Energies 2014, 7(4), 2558-2572; doi:10.3390/en7042558
Received: 25 February 2014 / Revised: 31 March 2014 / Accepted: 1 April 2014 / Published: 22 April 2014
Cited by 4 | PDF Full-text (2450 KB) | HTML Full-text | XML Full-text
Abstract
The realistic three dimensional (3D) microstructure of lithium ion battery (LIB) electrode plays a key role in studying the effects of inhomogeneous microstructures on the performance of LIBs. However, the complexity of realistic microstructures imposes a significant computational cost on numerical simulation [...] Read more.
The realistic three dimensional (3D) microstructure of lithium ion battery (LIB) electrode plays a key role in studying the effects of inhomogeneous microstructures on the performance of LIBs. However, the complexity of realistic microstructures imposes a significant computational cost on numerical simulation of large size samples. In this work, we used tomographic data obtained for a commercial LIB graphite electrode to evaluate the geometric characteristics of the reconstructed electrode microstructure. Based on the analysis of geometric properties, such as porosity, specific surface area, tortuosity, and pore size distribution, a representative volume element (RVE) that retains the geometric characteristics of the electrode material was obtained for further numerical studies. In this work, X-ray micro-computed tomography (CT) with 0.56 μm resolution was employed to capture the inhomogeneous porous microstructures of LIB anode electrodes. The Sigmoid transform function was employed to convert the initial raw tomographic images to binary images. Moreover, geometric characteristics of an anode electrode after 2400 cycles at the charge/discharge rate of 1 C were compared with those of a new anode electrode to investigate morphological change of the electrode. In general, the cycled electrode shows larger porosity, smaller tortuosity, and similar specific surface area compared to the new electrode. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)

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Open AccessCorrection Correction: Marino, M.; Misuri, L.; Carati, A.; Brogioli, D. Proof-of-Concept of a Zinc-Silver Battery for the Extraction of Energy from a Concentration Difference. Energies 2014, 7, 3664–3683
Energies 2014, 7(8), 5500-5501; doi:10.3390/en7085500
Received: 2 July 2014 / Accepted: 2 July 2014 / Published: 22 August 2014
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Abstract We would like to change the authors’ affiliations on Page 3664 of paper [1] from:[...] Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
Open AccessDiscussion Understanding of Sulfurized Polyacrylonitrile for Superior Performance Lithium/Sulfur Battery
Energies 2014, 7(7), 4588-4600; doi:10.3390/en7074588
Received: 20 May 2014 / Revised: 17 June 2014 / Accepted: 10 July 2014 / Published: 18 July 2014
Cited by 15 | PDF Full-text (998 KB) | HTML Full-text | XML Full-text
Abstract
Sulfurized polyacrylonitrile (SPAN) is one of the most important sulfurized carbon materials that can potentially be coupled with the carbonaceous anode to fabricate a safe and low cost “all carbon” lithium-ion battery. However, its chemical structure and electrochemical properties have been poorly [...] Read more.
Sulfurized polyacrylonitrile (SPAN) is one of the most important sulfurized carbon materials that can potentially be coupled with the carbonaceous anode to fabricate a safe and low cost “all carbon” lithium-ion battery. However, its chemical structure and electrochemical properties have been poorly understood. In this discussion, we analyze the previously published data in combination with our own results to propose a more reasonable chemical structure that consists of short –Sx– chains covalently bonded onto cyclized, partially dehydrogenated, and ribbon-like polyacrylonitrile backbones. The proposed structure fits all previous structural characterizations and explains many unique electrochemical phenomena that were observed from the Li/SPAN cells but have not been understood clearly. Full article
(This article belongs to the Special Issue Electrochemical Energy Storage—Battery and Capacitor)
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