The invention provides a parallel lithium ion battery pack virtual connection and internal resistance increase fault identification method. The battery pack is formed by connecting n single batteriesin parallel, the parallel battery pack is regarded as a battery, and the total current, tab voltage, total voltage and surface temperature of the battery are recorded. The battery impedance is identified on line based on the equivalent circuit model and recursive least square, and if the battery impedance is greater than a threshold value, it is determined that an impedance increase fault exists.The impedance standard deviation is further calculated, if the impedance standard deviation is greater than the threshold and the duration is greater than the preset time, it is determined the fault is virtual connection, and otherwise, it is determined that the internal resistance is increased. If the tab voltage of the battery i is lower than that of other batteries during charging and higher than that of other batteries during discharging, the battery i is in virtual connection; and if the battery i does not exist and the temperature of the battery j is higher than that of other batteries,the internal resistance of the battery j is increased. When the temperature difference between the batteries is greater than 5 DEG C, it is determined that a first-stage fault occurs. Identification,positioning and grading of virtual connection and internal resistance increase faults of the parallel battery pack can be realized.
本发明提出一种并联锂离子电池组虚拟连接与内阻增加故障辨识方法,电池组由n节单体电池并联,将并联电池组视为一个电池,记录电池总电流、极耳电压、总电压、表面温度。基于等效电路模型和递归最小二乘在线辨识电池阻抗,若其大于阈值,则存在阻抗增加故障。进一步计算阻抗标准差,若其大于阈值且持续时间大于预设时间,则故障为虚拟连接,相反,则是内阻增加。若存在电池i极耳电压在充电时低于其他电池,放电时高于其他电池,则电池i发生虚拟连接;若电池i不存在,存在电池j温度高于其他电池,则电池j发生内阻增加。当电池间温差大于5℃时,认定为一级故障。本发明可以实现并联电池组虚拟连接与内阻增加故障的辨识、定位与分级。
Parallel lithium ion battery pack virtual connection and internal resistance increase fault identification method
一种并联锂离子电池组虚拟连接与内阻增加故障辨识方法
2020-11-24
Patent
Elektronische Ressource
Chinesisch
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