一种复合型充电均衡系统及控制方法

A Composite Charging Equalization and Control Method

针对串联锂离子电池组中各个单体电池的差异造成充电过程中各单体电池之间能量不均衡的问题,提出了一种复合型充电均衡系统及控制方法.在充电过程中利用分层并联均衡逐级减小各单体电池的SOC差异,使各单体电池SOC保持一致性.若电池组满足旁路均衡条件则对电池组采用旁路均衡,使高SOC单体电池迅速接近平均SOC,大幅提高均衡效率.并联均衡与旁路均衡的充分结合,使得充电过程中各单体电池SOC迅速趋于一致.对8个串联的磷酸铁锂电池(LiFePO4)分别进行串联充电参照实验和复合型均衡充电实验,通过多角度对两组实验进行对比,充分证明了该均衡策略在均衡效果和速度上都有很好的作用.

In order to solve the problem of energy imbalance in the charging process caused by the differences of individual cells in series lithium-ion batteries, this paper proposes a compound charging equalization system and control method. In the charging process, hierarchical parallel equalization is used to reduce the SOC difference of individual batteries gradually, so that the SOC of individual batteries keeps consistency. When the battery pack satisfies the bypass equalization condition, bypass equalization is adopted for the battery pack, which enables the high SOC cell approach the average SOC quickly, and greatly improves the equalization efficiency. The combination of parallel equalization and bypass equalization makes the SOC of individual batteries converge rapidly in the charging process. Eight lithium iron phosphate batteries(LiFePO4) in series were used to conduct series charging reference experiments and composite equalization charging experiments respectively. By comparing the two groups of experiments from different angles, it is fully proved that the equalization strategy has good equalization effect and equalization speed.