一种基于直流内阻的电池组连接可靠性的检测方法

串并联成组后,电池的直流内阻由单体电池本身的直流内阻和极柱连接部分的接触电阻组成。电池组中某支电池连接不良时,该电池的直流内阻会高于其他电池。从直流内阻角度,提出直流内阻偏差(ΔR)这一指标对电池组的连接可靠性进行评测。考虑到ΔR计算操作复杂、故障识别慢的缺点,进一步提出电池组在30%~60%SOC下,1 C放电1 min结束时压差(ΔU)的评测指标。同时给出了该指标合格的阈值设定方法。试验结果表明:(1)在要求的SOC下,ΔU和ΔR与电流的乘积基本一致,完全可以代替ΔR表征电池组的连接状况,并且表征能力更加明显;(2)根据ΔU的合格阈值,可以实现电池极柱螺栓松动、连接部位氧化等连接不良问题的快速检测、有效识别。

Research on battery connection reliability based on DC internal resistance

Battery DC internal resistance (DCIR) includes the resistance of cell itself and the contact resistance of connecting position after serial and parallel connection.Battery's DC internal resistance can rise if it connects unwell.Based on the DCIR of cell,the deviation of DCIR (ΔR) as the test index of battery connection reliability was proposed.Considering the shortcoming of ΔR in operation and fault recognition,another index instead of ΔR was proposed.It was the voltage difference of battery at the end of one minute discharge process with 1 C current,when the battery pack at 30％～60％ SOC.It could be defined as ΔU.The passing standard of ΔU was provided.The test results show that ΔU is almost equal to the product of ΔR and current.So ΔU can be used as the test index of battery connection reliability and it increase more obviously than ΔR when any position connects unwell in the battery.According to the passing standard of ΔU,it can identify the unwell connection situation effectively and quickly.