基于自放电阻抗变化的锂电池存储容量衰减评估技术  

Evaluation of Lithium Battery Storage Capacity Degradation Based on Self-discharge Impedance Change

作　　者：董明[1] 李晓枫 熊锦晨 刘王泽宇 罗阳 任明[1] DONG Ming;LI Xiaofeng;XIONG Jinchen;LIU Wangzeyu;LUO Yang;REN Ming(State Key Library of Electrical Insulation and Power Equipment(Xi’an Jiaotong University),Xi'an 710049,Shaanxi Province,China)

机构地区：[1]电力设备电气绝缘国家重点实验室(西安交通大学),陕西省西安市710049

出　　处：《中国电机工程学报》2025年第3期1052-1062,I0020,共12页PROCEEDINGS OF THE CHINESE SOCIETY FOR ELECTRICAL ENGINEERING

基　　金：国家电网有限公司科技项目(4000-202499063A-1-1-ZN)。

摘　　要：随着锂电池在动力和储能等领域得到广泛应用,锂电池的寿命问题成为限制其发展的重要桎梏。电池处于存储状态时也会发生性能衰退而影响寿命,因此,研究电池自放电过程中的阻抗变化以表征内部电化学反应与结构相变过程,对于电池寿命模型完善有十分重要的意义。基于此,该文通过容量增量曲线对电池容量衰减的内因展开分析;在不同影响因素下自放电过程中电池阻抗谱变化规律的基础上,利用弛豫时间分布法进行理论原理分析;最后,在电池自放电老化过程的原理推导的基础上总结电池容量衰减量随时间的变化规律,并结合实验数据建立不同影响因素下电池容量衰减模型。结果表明,在存储过程中,电池的固体电解质界面(solid electrolyte interface,SEI)膜内阻增大,且存储温度越高、初始充电状态(state of charge,SOC)越大,相应的阻抗增加幅度越大。自放电过程电池老化主要原因是可循环活性锂离子的消耗和SEI膜的生长。同时该文推导出电池容量损失与时间近似呈0.5次方关系,并利用实验数据拟合得到电池在不同初始SOC和不同存储温度影响下的容量变化模型,为锂电池寿命模型预测提供更进一步的参考。With the wide application of lithium batteries in the fields of power and energy storage,the lifetime of lithium batteries has become an important shackle limiting their development.Considering the fact that the battery in storage state will also undergo performance degradation and affect the lifetime,it is of great significance to study the impedance change during the self-discharge process of the battery.This study aids in characterizing internal electrochemical reactions and structural phase transitions,which are essential for enhancing battery lifespan models.This paper analyses the internal causes of battery capacity degradation through the capacity increment curve.Meanwhile,on the basis of the variation of the impedance spectrum of the battery in the self-discharge process under different influencing factors,this paper analyses the theoretical principle by using the relaxation time distribution method.Finally,on the basis of the principle derivation of the battery self-discharge aging process,this paper summarizes the variation of battery capacity degradation with time,and combines the experimental data to establish the battery capacity degradation model under different influencing factors.The results show that the internal resistance of the solid electrolyte interface(SEI)of the battery increases during the storage process,and the corresponding increase in impedance is greater when the storage temperature of the battery is higher and the initial state of charge(SOC)is larger.The main reasons for battery aging during self-discharge are the consumption of recyclable active lithium ions and the growth of SEI.Meanwhile,this paper deduces that the capacity loss of the battery is approximately 0.5 power relationship with time,and uses the experimental data to fit to obtain the capacity change model of the battery under the influence of different initial SOC and different storage temperatures,which provides a further reference for the prediction of lithium battery life model.

关 键 词：锂离子电池 自放电 弛豫时间分布 固体电解质界面膜内阻 容量衰减模型 

分 类 号：TM912[电气工程—电力电子与电力传动]