不同充放电倍率下的锂电池声发射信号分析

锂离子电池充放电倍率是影响电池老化的主要外部应力之一，充放电倍率过大可能使电池内部电流分布不均，导致锂沉积或电极活性材料结构疲劳变形。基于声发射方法研究了不同充放电倍率下的电池状态。通过设计锂离子电池声发射信号试验平台，采集了不同充放电倍率下的电池声发射信号。对声发射信号进行参数与波形分析，发现声发射信号主要存在两个突发型的波形，且充电与放电的声发射信号波形的初次穿越阈值的采样点符号相反。锂离子电池声发射信号的幅度和波形时间间隔都与电池的充放电倍率相关，电池充放电倍率越大，声发射信号幅度越高，波形时间间隔越小。

Analysis of Acoustic Emission Signals of Lithium-Ion Batteries at Different Charge and Discharge Rates

The charge-discharge rate of lithium-ion batteries is a major external stress that affects battery aging.Excessive charge-discharge rate may cause uneven current distribution inside the battery,resulting in lithium deposition or fatigue deformation of the electrode active material structure.The acoustic emission method is used to study different battery status at charge and discharge rates.By designing the acoustic emission signal test platform of lithium-ion battery,the acoustic emission signals of battery under different charge and discharge rates are collected.The parameters and waveforms of the acoustic emission signal are analyzed,and it is found that there are mainly two burst waveforms in the acoustic emission signal,and the signs of the sampling points that first crossing threshold of the charging and discharging acoustic emission signal waveforms are opposite.The amplitude and waveform time interval of the acoustic emission signal of the lithium-ion battery are related to the charging and discharging rate of the battery.The larger the charging and discharging rate of the battery,the higher the amplitude of the acoustic emission signal and the smaller the waveform time interval.