一种延长电动汽车蓄电池寿命的均衡充电控制策略

电动汽车用动力电池组都是由多个单体电池串联而成,由于单体电池的性能不可能完全一致,串联使用过程中,初期的细微差异在每次充放电的放大作用下,一段时间后单体电池间的性能差异就会逐渐增大,从而导致电池组性能急剧下降和循环寿命缩短。通过分析电池组提前失效的原因,针对耗散型均衡控制电路,深入研究电池组均衡充电控制的电路模型,并在此基础上提出一种既能够实现电池组快速充电,又能够消除单体电池不一致对电池组循环寿命影响的均衡充电控制策略。根据所提出的均衡充电控制策略,对72 V/120 AH铅酸蓄电池组进行对比测试,实验结果说明了该策略的有效性。

An Equalizing Charge Control Strategy to Extend Battery Cycle Life for Electric Vehicles

In electric vehicles,battery string with many cells in series connection can provide higher voltage.But for each cell,any slight voltage difference can be amplified in the charging and discharging cycles.Unbalanced cell voltage in battery string will give rise to serious over-charging or over-discharging,and decrease the total storage capacity and the battery cycle life.Therefore,maintaining cell voltage at an equal charge/discharge level is significant for enhancing the battery cycle life.Aiming at the dissipative equalization circuits,the circuit model of battery equalization charge was studied,and an equalization charge control strategy which can not only achieves quick charge but also increases the battery cycle life was proposed.According to the proposed charge control strategy,corresponding experiments were implemented based on 72 V/ 120 AH laid-acid battery,and the experimental results show its feasibility and effectiveness.