Influence of connecting plate resistance upon LiFePO4 battery performance

Wang, Limei; Yong, Cheng; Zhao, Xinbing

doi:10.1016/j.apenergy.2015.03.016

Cited by 44 publications

(16 citation statements)

References 25 publications

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“…The simulation model is established by the Simscape module and language [23][24][25]. Each circuit element is a subsystem composed of a customized electrical module; the module is used to calculate the circuit parameters.…”

Section: Single Cell Simulation Modelmentioning

confidence: 99%

Online Diagnosis for the Capacity Fade Fault of a Parallel-Connected Lithium Ion Battery Group

et al. 2016

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In a parallel-connected battery group (PCBG), capacity degradation is usually caused by the inconsistency between a faulty cell and other normal cells, and the inconsistency occurs due to two potential causes: an aging inconsistency fault or a loose contacting fault. In this paper, a novel method is proposed to perform online and real-time capacity fault diagnosis for PCBGs. Firstly, based on the analysis of parameter variation characteristics of a PCBG with different fault causes, it is found that PCBG resistance can be taken as an indicator for both seeking the faulty PCBG and distinguishing the fault causes. On one hand, the faulty PCBG can be identified by comparing the PCBG resistance among PCBGs; on the other hand, two fault causes can be distinguished by comparing the variance of the PCBG resistances. Furthermore, for online applications, a novel recursive-least-squares algorithm with restricted memory and constraint (RLSRMC), in which the constraint is added to eliminate the "imaginary number" phenomena of parameters, is developed and used in PCBG resistance identification. Lastly, fault simulation and validation results demonstrate that the proposed methods have good accuracy and reliability.

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Section: Single Cell Simulation Modelmentioning

confidence: 99%

Online Diagnosis for the Capacity Fade Fault of a Parallel-Connected Lithium Ion Battery Group

et al. 2016

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“…Inconsistency among cells is a serious problem in battery energy storage systems, in which the lithium batteries have to be connected in series to meet the voltage and capacity requirements of the application [1][2][3][4][5][6][7][8][9]. Because of the surrounding environments, self-discharge rates, and fabrication process of batteries, the charge level tends to vary from cell to cell [4,[9][10][11]. Battery inconsistency is usually expressed as differences in internal resistance, voltage, and charge imbalance [3,10,12,13].…”

Section: Introductionmentioning

confidence: 99%

“…Battery inconsistency is usually expressed as differences in internal resistance, voltage, and charge imbalance [3,10,12,13]. The inconsistency reduces battery lifetimes and increases their usage costs [3,[10][11][12]14]. For the purposes of bringing cells to the same charge level and achieving high performance, cell equalization technology (CET) has been developed [2,5,10,[14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Influence of equalization on LiFePO₄battery inconsistency

Song

Lin

et al. 2017

Int. J. Energy Res.

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SUMMARY Capacity inconsistency among cells is a serious problem in battery energy storage systems. The inconsistency reduces battery pack lifetimes and increases their usage costs. Active balancing is an effective technique for performance equalization between cells. Here, a quantitative analysis method based on an active balancing circuit is developed to explain how battery capacity inconsistency is affected by balancing parameters. Four balancing parameters, namely, charge/discharge current rate, initial capacity difference before balancing, balancing current, and balancing time, have been considered to explain the effects on battery capacity consistency. The results indicate that (1) the inconsistency of batteries can be reduced more effectively for discharging with active balancing at small current rates; (2) for an improved balancing effect, it is necessary to maintain a high ratio (β) of balancing current to charging/discharging current during the balancing process; thus, a larger balancing current is significant; (3) the value of capacity difference reduction ratio (α) grows more dramatically in discharging at large initial battery capacity differences; and (4) when the balancing current only marginally changes, following the increase of current rate, the ratio (γ) of balancing time to charging duration decreases and the balancing effect becomes inconspicuous in charging, while γ increases and the balancing effect reduces in discharging. These influence regulations can help us make and optimize balancing control strategies for LiFePO4 batteries. Copyright © 2017 John Wiley & Sons, Ltd.

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“…The integration of unmatched cells which show variations due to manufacturing tolerances can cause inhomogeneity within battery modules. 2,7,9,10,12,13 Furthermore, it can also be caused by different external reasons, for example asymmetrical cell connectors which result in uneven cell connector resistances, 14 uneven 14 or defective cell contacts, 15,16 a disadvantageous cell arrangement, an ineffective cooling strategy 17 or an external heat source next to the battery module. 18,19 These external reasons lead to a thermal gradient across the battery module.…”

mentioning

confidence: 99%

“…[25][26][27] Investigations which model the inhomogeneity in battery modules have mostly used equivalent circuit models (ECMs) for the single connected cells. [6][7][8][9][10]14,15,[21][22][23][24]26,[29][30][31]33 Only a handful of groups have used physicochemical models (PCMs) for the cells 16,19,28,32 which are more demanding in terms of model parameterization and computational time compared to ECMs. However, using PCMs allows for an implementation of temperature dependent transport and kinetics parameters and moreover for a discussion from an electrochemical point of view due to a deeper insight into the electrochemical reactions during module operation.…”

mentioning

confidence: 99%

Influence of Cell-to-Cell Variations on the Inhomogeneity of Lithium-Ion Battery Modules

Rumpf

Rheinfeld

Schindler

et al. 2018

J. Electrochem. Soc.

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Inhomogeneity within lithium-ion battery modules can occur due to variations in capacity and impedance of the connected cells as well as due to thermal gradients or cell connector design. We present a model for describing xSyP battery modules during operation, which is able to study these effects. The multidimensional multiphysics model includes a physicochemical model describing the electrochemical behavior of each cell. The electrical model accounts for the conservation of electric charge and energy between the cells to reach electrical consistency according to the respective module topology and cell interconnections. The model is capable of investigating the influence of defective and asymmetric cell connectors on the inhomogeneity of module operation. To evaluate this electrical influence, the observed inhomogeneities are compared to the influence of thermal gradients between the cells. The resulting inhomogeneous current distribution is presented for a module of two parallel connected lithium iron phosphate-graphite cells under constant current discharge operation for variations in cell capacity, cell impedance and ambient temperature at different module contact scenarios. From the observed impact of both, electrical and thermal variations between parallel connected cells, a matching strategy is derived and discussed which can enhance a module's performance during e.g. second life applications.

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Influence of connecting plate resistance upon LiFePO4 battery performance

Cited by 44 publications

References 25 publications

Online Diagnosis for the Capacity Fade Fault of a Parallel-Connected Lithium Ion Battery Group

Online Diagnosis for the Capacity Fade Fault of a Parallel-Connected Lithium Ion Battery Group

Influence of equalization on LiFePO₄battery inconsistency

Influence of Cell-to-Cell Variations on the Inhomogeneity of Lithium-Ion Battery Modules

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Influence of connecting plate resistance upon LiFePO4 battery performance

Cited by 44 publications

References 25 publications

Online Diagnosis for the Capacity Fade Fault of a Parallel-Connected Lithium Ion Battery Group

Online Diagnosis for the Capacity Fade Fault of a Parallel-Connected Lithium Ion Battery Group

Influence of equalization on LiFePO4battery inconsistency

Influence of Cell-to-Cell Variations on the Inhomogeneity of Lithium-Ion Battery Modules

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Influence of equalization on LiFePO₄battery inconsistency