用于备用电源的三元锂离子电池交流阻抗分析

AC impedance analysis of ternary lithium ion battery for standby power supply

以三元锂离子为研究对象,通过模拟备用电源工况,测试得到电池交流阻抗谱,通过建立等效电路,研究欧姆阻抗Rs、电荷传递阻抗Rp和扩散阻抗CPEw随不同搁置时间、环境温度、荷电状态(state of charge,SOC)的变化规律。结果表明:在经过五个周期共140 d的搁置,常温搁置电池容量保持率为96.3%,高温45℃搁置电池容量保持率为83.7%。电池欧姆内阻和电荷传递阻抗有小幅增加,高温状态下变化趋势明显。

Taking the ternary lithium ion battery as the research object,the AC impedance spectrum of the battery was measured by simulating the working condition of the standby power supply.By establishing the equivalent circuit,the variation rules of ohmic impedance Rs,charge transfer impedance Rp and diffusion impedance CPEw with different shelving time,ambient temperature and state of charge(SOC)were studied.The results show that after five cycles of 140 days of storage,the capacity retention rate of batteries in normal temperature and high temperature is 96.3%and 83.7%,respectively.The ohmic internal resistance and charge transfer impedance of the battery increased slightly,and the change trend was obvious at high temperature.