一种锂电池充放电电流平衡算法的研究

Research on current-balancing algorithm of Li-ion battery charging and discharging

针对锂电池组中各电池容量不平衡导致电池过度充放电的问题,提出一种锂电池充放电电流平衡算法。通过给每个电池并联MOS管加限流电阻的负载实现电流的分流;在电流及电压的测量过程中提出二次差值法来消除内部电路对AD采样值的影响;对平衡算法的启动时间、条件及相关参数进行了分析和计算;对两节串联的锂电池进行电池电流平衡算法的测试。测试表明:经过平衡算法后,两节电池的充放电电压变化曲线接近一致,取得了满意的电池电流平衡效果。

According to excessive charge and discharge problem lead by the capacity imbalance of each cell of Li-ion battery, a current-balancing algorithm of Li-ion battery charging and discharging process was proposed. Current shunting was achieved by paralleling a load of a MOS with a current-limiting resistor to each cell. During the current and voltage measurement process,in order to eliminate the impact of the internal circuit on AD sampling value, twice difference method was proposed. Start-up time and conditions of the current-balancing algorithm and involving parameters were analyzed and calculated. The current-balancing algorithm was tested in the two-cell series battery.Experimental results show that the charge and discharge voltage curves for two cells are nearly identical by using the algorithm. Satisfactory battery current-balancing results were achieved.