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Electrochemical Impedance Spectroscopy (EIS) has become a popular analytical technique for research and development of battery cells' chemistries, due to the established, high precision computer controlled equipment, that are capable of direct, on-line monitoring of performance parameters or degradation of an electrochemical system. Used for Lithium-ion (Li-ion) batteries, this method allows for a...
To estimate state-of-charge (SOC) and state-of-health (SOH) of a lithium ion battery as exact as possible, the terminal voltage, the terminal current and the cell temperature have to be measured. The easiest model of a battery is an ohmic-capacitive (R-C) series-parallel circuit. Two measurement methods are shown how to get ready to estimate SOC and SOH in a simple but precise manner. The first measurement...
Estimation of the state of charge (SOC) is a critical parameter for the control of propulsion systems in plug-in hybrid electric vehicles (PHEV) and the electric vehicles (EVs). This paper proposes the SOC estimator of a Lithium-Ion battery using the adaptive extended Kalman filter (EKF). This method uses an optimization algorithm to update the EKF model parameters during a charge period. Accurate...
Battery 2nd life storage systems are a result of the synergies between the automotive and power generation sectors. They leverage the sustainability potential of electric vehicles (EVs) and renewable energy grid integration simultaneously. The vast experience of automobile manufacturers in battery system manufacturing and long-term operation in EVs provide a strong basis for replicating their success...
Modern lithium-ion batteries, like LiMO2/Li4Ti5O12 chemistry, are having very high power capability, which drives the need for precise thermal modelling of the battery. Battery thermal models are required to avoid possible safety issues (thermal runaways, high-temperature gradients) but also for the optimal battery pack design and for predicting battery electrical performance during operation (especially...
This paper deals with the characterization of Lithium batteries discharged by high power pulses. The experiments were conducted with a commercial ultra high power Li-Ion cell (A123 26650M1-A), which was tested by means of an ad - hoc implemented experimental setup under controlled climatic conditions. Performance reduction of the cell, in terms of capacity and efficiency losses, is analyzed and discussed...
Batteries are the most practical energy storage for mobile electrical devices. Aiming for more efficient battery systems results in new challenges for developers and scientists. Equipping a mobile device with an adequate battery typically requires an accurate model about the battery's behavior. To establish good models, precision measurements are necessary. In this paper we describe the development...
The cascade H-bridge topology is novel for the battery energy storage system (BESS). A multi-level battery management system (BMS), which contains three subsystems, is introduced. The functions and communication of each subsystem are discussed. An algorithm based on extended Kaiman filter is used for the state-of-charge (SOC) estimation in battery modules. The pack SOC is derived from those of the...
The goal of this paper is to describe the key methods for state of charge estimation. The presented techniques are current counting method, open circuit voltage and battery internal resistance method. This paper describes these methods and compares their accuracy.
This paper addresses the challenge of monitoring battery in fleets of electric vehicles (EV). The goal is to identify the different EV utilization modes, during real use, and to highlight the constraining conditions to manage battery health evolution. The other part of this study aims to build a battery capacity estimation model, permitting to estimate the remaining capacity of an EV during its real...
This paper describes a time-domain approach for estimating the state of health (SOH) and remaining useful life (RUL) of a battery, with particular emphasis on LiFePO4 cells. In this methodology, a small test signal is superimposed on top of the battery load to trigger its transient dynamics. The resulting terminal voltage and current are measured, and a nonlinear least-squares routine is used to estimate...
The open circuit voltage (OCV) characterization of Li-ion batteries as it applies to battery fuel gauging (BFG) in portable applications is considered in this paper. Accurate knowledge of the nonlinear relationship between the OCV and the state of charge (SOC) is required for adaptive SOC tracking during battery usage. BFG in portable applications requires this OCV-SOC characterization to be defined...
Various studies were conducted from the aspects of both the battery cells and the module with the aim of making more effective use of the battery capacity. As a result, after 77 cycles of driving and rapid charging, the capacity degradation of the battery module as a whole was 7.7 % and it was determined that the cause of this additional 0.7 % degradation of the capacity was the loss of cell balance...
In this contribution a multi-physical lithium-ion battery model is developed. The model, which is implemented in the programming language Modelica, focuses on the electric and thermal characteristics of the system. In order to obtain the parameters which are required to configure the model, measurements are performed directly on an electric vehicle during certain driving cycles. Further cycles are...
This paper describes a novel battery management system to accomplish all of the necessary functions to ensure the safe, reliable operation of lithium ion batteries. An interface circuit monitors each battery voltage and temperature. It includes a trickle charger that achieves cell balancing by active instead of passive means. A series loaded resonant converter with isolation, also known as an LLC...
Storage batteries are widely applied as backup power in different industries like telecom, power utility, and data center and so on. At the same time, real time knowledge about the battery condition (SOC and SOH) is very significant to ensure the performance of critical power system. However, existing methods of manual measurement for battery or online battery monitoring system will require complicated...
Uninterruptible power supply (UPS) systems have incorporated in their structure an electrochemical battery which allows for smooth power supply when a power failure occurs. In general, UPS systems are based on lead acid batteries; mainly a valve regulated lead acid (VRLA) battery. Recently, lithium ion batteries are getting more and more attention for their use in the back-up power systems and UPSs,...
Lithium ion batteries with iron phosphate cathodes are gradually improving in their performance and gaining importance, and are more and more considered for new applications. Different aspects of this chemistry were studied in numerous publications; however, very little research was devoted to detailed empirical investigations in order to find out how self-discharge of this chemistry depends on different...
Online diagnostics for monitoring of battery cells in a battery pack is necessary in order to determine the state of the battery pack, like its age and safe operation. It could also provide the possibility to adjust the operation strategy of the battery management system and the load to increase the battery lifetime and safety. Impedance spectroscopy is a well-known measurement technique for electrochemical...
This paper presents a comparative study of five sorting methods for Lithium-ion batteries. The principle of each method and the feather of the sorting parameters are obviously described firstly. Then, optimized implement the experiment on LiFePO4/graphite cells. Sorting results are clearly analyzed subsequently. By analyzes the relationship among the parameters, there are strong correlation between...
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