关键词: 汽车动力电池；早期故障诊断；修正方差；样本熵

Abstract: In order to solve the problem that it is difficult to detect the early minor faults of automotive power battery, this paper proposes a fault diagnosis method based on the combination of modified variance and sample entropy based on the actual operating voltage data of a vehicle. Firstly, the voltage data of the charging segment of a vehicle's power battery system is obtained to calculate the modified variance of each individual through the modified variance algorithm, and preliminarily determine the early fault according to the size of the individual variance. At the same time, combined with the change of entropy value of individual voltage sequence samples, accurate early fault diagnosis of automobile power battery is realized. The results show that the method proposed in this paper can effectively reduce the interference of battery cell voltage inconsistency, and dig out the early micro faults hidden in the battery cell as early as possible. At the same time, the fusion of sample entropy further improves the accuracy of early fault diagnosis.

Key words: Automobile power battery; Early fault diagnosis; Corrected variance; Sample entropy