在线阻抗测量的锂电池过充预警和热失控预测方法

On-line Impedance Measurement of Lithium Battery Overcharge Warningand Thermal Runaway Prediction

本文提出一种锂电池的过充实时预警和热失控早期预测方法,以避免过充引起的热失控事故。通过研究发现在电池刚开始过充电时,30~90 Hz频段内动态阻抗的斜率由负变为正,并提出了理论解释。以70 Hz阻抗为例,在充电过程中,通过斜率从负转向正,可以成功避免热失控事故的发生。警告时间是热离场前580 s。这个特性很容易识别,不需要复杂的数学模型和参数。此外,基于该特征的预测方法可以使用本文所提出的在线动态阻抗测量装置进行。最后,通过实验验证了本文所提方法的有效性。

In the paper,a method of overcharging warning and early prediction of thermal runaway of lithium battery is proposed.In this paper,it is found that the slope of the dynamic impedance in the 30~90 Hz band changes from negative to positive at the beginning of overcharging of the battery,and a theoretical explanation is proposed.Taking 70 Hz impedance as an example,during the charging process,the thermal runaway accident can be successfully avoided by cutting off the slope from the negative pole to the charging position.Warning time is 580 seconds before hot exit.This feature is easy to identify and does not require complex mathematical models and parameters.In addition,the prediction method based on this feature can be carried out by using the on-line dynamic impedance measuring device proposed in this paper.Finally,the effectiveness of the proposed method is verified by experiments.