基于容量增量曲线与充电容量差的电池组微短路诊断方法

Micro Short Circuit Diagnosis Method of Battery Pack Based on Capacity Increment Curve and Charge Capacity Difference

目前还没有一种有效的手段针对处于前期演化阶段的锂离子电池微短路进行检测,为此本文提出了一种基于电池充电容量增量(IC)曲线和充电容量差(DCC)变化规律的微短路故障诊断方法。首先确立锂电池短路故障与充电容量增量的关系,利用小波变换对IC曲线进行降噪,得出在不同电流倍率和温度下IC曲线最高峰(ICPV)与电池荷电状态(SOC)唯一对应。然后提出利用充电容量差DCC描述存在内短路的故障电池与正常电池的SOC差异,并据此得出锂电池微短路的量化方法。最后通过仿真分析与实验验证表明,在不同工况下循环测试均可获得电池微短路的量化信息,且诊断最大误差均小于8.12%。

At present,there is no effective method to identify and detect the micro short circuit of lithiumion battery in the early evolution stage.Therefore,this paper proposes a micro short circuit diagnosis method based on the change law of battery charge capacity increment(IC)curve and charge capacity difference(DCC).Firstly,the relationship between lithium battery short circuit fault and charge capacity increment is established.The IC curves are denoised by using wavelet transform,and the unique correspondence between the peak value of IC curve(ICPV)and the state of charge(SOC)of battery is obtained under different current rates and temperature.Then,DCC is proposed to be used to describe the SOC difference between the faulty battery with internal short circuit and the normal battery,and the quantitative method of lithium battery micro short circuit is obtained.Finally,simulation analysis and experiments show that the quantitative information of battery micro short circuit can be obtained under different cycling conditions,and the maximum errors of fault diagnosis are less than 8.12%.