过充循环对锂离子电池容量衰减及安全性影响  

Effect of overcharge cycle on capacity attenuation and safety of lithium-ion batteries

作　　者：许卓 李希超 贾隆舟 陈兵 戴作强[1,2,3] 郑莉莉[1,2,3] XU Zhuo;LI Xichao;JIA Longzhou;CHEN Bing;DAI Zuoqiang;ZHENG Lili(College of Mechanical and Electrical Engineering;Engineering Technology Center of Power Integration and Energy Storage System,Qingdao University;National and Local Joint Engineering Technology Center for Intelligent Power Integration Technology for Electric Vehicles(Qingdao),Qingdao 266071,Shandong,China)

机构地区：[1]青岛大学机电工程学院 [2]青岛大学动力集成及储能系统工程技术中心 [3]电动汽车智能化动力集成技术国家地方联合工程技术中心(青岛),山东青岛266071

出　　处：《储能科学与技术》2022年第12期3978-3986,共9页Energy Storage Science and Technology

基　　金：电动汽车储电系统电(储能电池)-电(动力电池/超级电容)耦合成组技术研究(40518060027)。

摘　　要：随着能源问题的出现,锂离子电池已成为人们关注的热点。本工作以18650型NCM811锂离子电池为研究对象,将电池过充至3个不同的截止电压(4.3 V、4.4 V、4.5 V)并循环一定的次数(180次)直到电池容量大幅度衰减,基于测试分析4.5 V过充循环电池的交流阻抗谱和容量增量曲线来定性和定量地研究电池容量衰减机理。研究发现活性锂离子的损失和活性材料的损失是电池容量衰减的主要原因,电池电导率的损失对电池容量衰减影响不大。通过绝热加速量热仪(adiabatic rate calorimeter,ARC)研究新电池,4.3 V、4.4 V和4.5 V过充循环电池在100%SOC下的热失控特征参数(自产热起始温度T_(1)、热失控触发温度T_(2)、热失控最高温度T_(3))。发现在热失控发生过程中,电池达到相同的温度时,4个电池的温升速率大小分别是新电池<4.3 V过充循环电池<4.4 V过充循环电池<4.5 V过充循环电池。电池在经过过充循环之后热稳定性变差。过充循环后,电池的自产热起始温度降低、热失控触发温度降低。Lithium-ion batteries have become a hot spot with the emergence of energy problems.This study takes the 18650 NCM811 lithium-ion battery as the research object.It overcharges the battery to three different cut-off voltages(4.3 V,4.4 V,and 4.5 V)and cycles it several times(180 times)until the battery capacity decays significantly.The test and analysis of the 4.5 V overcharged circulating battery’s AC impedance spectrum and capacity increment curve reveal the mechanism of battery capacity decay,which is studied both qualitatively and quantitatively.It was discovered that the main cause of battery capacity attenuation is the loss of active lithium ions and active materials,whereas the loss of battery conductivity has little effect.The thermal runaway characteristic parameters(self-heating starting temperature T_(1),thermal runaway triggering temperature T_(2),maximum thermal runaway temperature T_(3))of new batteries,4.3 V,4.4 V,and 4.5 V,overcharged circulating batteries at 100% SOC,which was investigated by adiabatic rate calorimeter.It was found that in the thermal runaway process when the battery reached the same temperature,the temperature rise rates of the four batteries were new battery<4.3 V overcharge cycle battery<4.4 V overcharge cycle battery<4.5 V overcharge cycle battery,respectively.The thermal stability of the battery becomes worse after the overcharge cycle.After the overcharge cycle,the starting temperature of the self-generated heat of the battery decreases.In addition,the trigger temperature of the thermal runaway decreases.

关 键 词：锂离子电池 过充循环 电化学阻抗谱 热失控 

分 类 号：TM912[电气工程—电力电子与电力传动]