磷酸铁锂电池并联充放电特性研究

Research on charging and discharging characteristics of parallel connection for LiFePO4 Li-ion batteries

针对动力锂离子电池成组后性能比单体性能明显降低的问题，分析了电池不一致性产生的原因，在此基础上，研究了电池单体充放电性能和老化过程一定时，电池的成组方式和电池参数不一致程度对整组电池性能的影响。重点以磷酸铁锂电池为研究对象，分别对不同并联电池数量和不同充放电倍率进行了实验，分析了电池并联情况下直流内阻、电池容量、极化电压、荷电状态等因素对电池工作电流和电压的影响，提出了并联电池不平衡电流的判断依据，从而为电池系统的容量设计和提高成组电池的性能提供依据。

The problem that the performance of power Li-ion battery packs degrade more obviously compared to a single cell due to the battery inconsistency is paid attention, and the analysis of the reasons causing the battery inconsistentcy is presented. Apart from the factors of cell feature and cell aging process, the influences of the grouping approach and the parameter inconsistency of a battery pack on its behavior are investigated. The charging and discharging characteristics of paralleled LiFePO4 batteries are given based on the analyses of the performed experiments on varying the parallel connected battery number and varying the current rate. Moreover, the basis for judging the disequilibrium current of a parallel connected battery is proposed. The purpose of this paper is to provide the evidence to design the capacity of a battery pack and improve the battery performance.