新充电方案对锂离子电池组循环性能的影响

Effect of new charging program on the cyclic performance of Li-ion battery

用传统充电方案与新的充电方案交叉的方法对36V/10Ah LiFePO4锂离子电池组进行循环性能测试,结果发现:新的充电方案可以在一定程度上提升电池组的循环性能,对于单体性能差异较大的电池组,其改善效果尤为明显。通过实验分析发现,电池组循环性能的衰减主要是由于电池组整体的差异性而使得充电容量的衰减,而非单体性能的下降。另外,通过对电池组中3个单体进行单独放电而故意加剧电池组间单体电池荷电状态失衡,从而模拟实际使用过程中可能会出现的单体间自放电率差异较大的情形。在此种状态下,新的充电方案可以通过10次的循环过程将电池组容量恢复至正常水平。因此,新的充电方案可以有效地均衡电池组间单体容量差异,从而避免使用过程中由于单体间自放电差异的存在和累积而导致电池组寿命的急剧缩短。

In this paper,the cyclic performance tests of 36V/10Ah LiFePO4 Li-ion batteries were performed with traditional charging method and a novel charging program.The results showed that the novel charging program,to a certain extent,could improve the cyclic performance of the batteries,especially for those with great difference between the constituent cells,and it was found that the degradation of the cyclic performance of the batteries could be mainly attributed to the difference between the constituent cells rather than the degradation of the cells＇ performance.In the experiment,some condition that the battery had self-discharge difference between constituent cells was simulated,and the experiments results showed that the capacity of the battery could be recovered to the normal level through 10 charge-and-discharge cycles with the novel charging program.Therefore,the novel charging program could effectively reduce the capacity imbalance between the constituent cells of the batteries with self-discharging,avoiding the dramatic reduction in the expectancy of the batteries under the operation conditions.