微过充下三元镍钴铝锂离子电池的老化机理  

Aging mechanism of ternary NCA Li-ion battery under slight overcharge

作　　者：王岩松 陈顺 范国栋[1,2] 张希 WANG Yansong;CHEN Shun;FAN Guodong;ZHANG Xi(School of Mechanical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;National Engineering Research Center of Automotive Power and Intelligent Control,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]上海交通大学机械与动力工程学院,上海200240 [2]上海交通大学国家汽车动力与智能控制工程技术研究中心,上海200240

出　　处：《电池》2024年第2期154-159,共6页Battery Bimonthly

基　　金：国家自然科学基金(52177218,52307246),上海市自然科学基金(23 ZR1429100)。

摘　　要：电芯的不一致性及电量不均衡,会导致部分锂离子电池单体出现微过充现象,但此情况对于电池容量的影响未被完全揭示。在不同最高截止电压(4.2 V、4.3 V和4.4 V)下对三元镍钴铝(Li_(x)Ni_(0.80)Co_(0.15)Al_(0.05)O_(2))电池进行恒流充电循环老化实验,采用差分电压分析、电化学阻抗谱(EIS)等测试方法,探究高截止电压循环对电池老化的影响。随着最高截止电压的升高,电池老化速度加快,以2.5 A电流循环280次后,4.2 V、4.3 V、4.4 V下的容量保持率分别为90.30%、88.19%和86.19%。差分电压分析表明,容量衰减加速的原因是正极活性物质损失和活性Li+损失。EIS测试表明,微过充导致固体电解质相界面(SEI)膜阻抗略微升高,电荷转移阻抗升高,且程度随截止电压的升高而增大。The inconsistency of the cells and inadequate charge balancing can result in slight overcharging of some Li-ion battery cells.The impact of this condition on battery capacity has not been fully elucidated.Galvanostatic charging and cycling aging experiments on NCA(Li_(x)Ni_(0.80)Co_(0.15)Al_(0.05)O_(2))batteries at different maximum cut-off voltages(4.2 V,4.3 V and 4.4 V)are conducted and test methods such as differential voltage analysis and electrochemical impedance spectroscopy(EIS)are used to investigate the effects of high cut-off voltage cycling on battery aging.As the maximum cut-off voltage increases,the rate of battery aging accelerates.After 280 cycles at 2.5 A,the capacity retention at 4.2 V,4.3 V and 4.4 V is 90.30%,88.19%and 86.19%,respectively.Differential voltage analysis reveals that the accelerated capacity decay is due to the loss of cathode active materials and active Li+.EIS test discloses that hte mild overcharging leads to a slight increase in the impedance of the solid electrolyte interphase(SEI)film,and an increase in the charge transfer impedance,the extent of which increase with the increase of the cut-off voltage.

关 键 词：锂离子电池 镍钴铝(Li_(x)Ni_(0.80)Co_(0.15)Al_(0.05)O_(2)) 微过充 高截止电压 老化模式 活性物质损失 电荷转移阻抗 

分 类 号：TM912.9[电气工程—电力电子与电力传动]