Investigation on step overcharge to self-heating behavior and mechanism analysis of lithium ion batteries  

作　　者：Fengling Yun Shiyang Liu Min Gao Xuanxuan Bi Weijia Zhao Zenghua Chang Minjuan Yuan Jingjing Li Xueling Shen Xiaopeng Qi Ling Tang Yi Cui Yanyan Fang Lihao Guo Shangqian Zhao Xiangjun Zhang Shigang Lu 

机构地区：[1]China Automotive Battery Research Institute Co.,Ltd.,Beijing 101407,China [2]China Electric Power Research Institute,Beijing 100192,China [3]China GRINM Group Corporation Limited(GRINM Group),Beijing 100088,China [4]GRINM(GuangDong)Advanced Materials Technology Research Institute,Foshan 528000,Guangdong,China [5]General Research Institute for Nonferrous Metals,Beijing 100088,China [6]Institute of Materials Genome Engineering,Shanghai University,Shanghai 200444,China

出　　处：《Journal of Energy Chemistry》2023年第4期301-311,共11页能源化学（英文版）

基　　金：funded by the National Key Research and Development Program of China(2018YFB0104400);supported by the Beijing Natural Science Foundation(2214066)。

摘　　要：To obtain intrinsic overcharge boundary and investigate overcharge mechanism,here we propose an innovative method,the step overcharge test,to reduce the thermal crossover and distinguish the overcharge thermal behavior,including 5%state of charge(SOC)with small current overcharge and resting until the temperature equilibrium under adiabatic conditions.The intrinsic thermal response and the self-excitation behaviour are analysed through temperature and voltage changes during the step overcharge period.Experimental results show that the deintercalated state of the cathode is highly correlated to self-heating parasitic reactions.Before reaching the upper limit of Negative/Positive(N/P)ratio,the temperature changes little,the heat generation is significantly induced by the reversible heat(endothermic)and ohmic heat,which could balance each other.Following that the lithium metal is gradually deposited on the surface of the anode and reacts with electrolyte upon overcharge,inducing selfheating side reaction.However,this spontaneous thermal reaction could be“self-extinguished”.When the lithium in cathode is completely deintercalated,the boundary point of overcharge is about 4.7 V(~148%SOC,>40℃),and from this point,the self-heating behaviour could be continuously triggered until thermal runaway(TR)without additional overcharge.The whole static and spontaneous process lasts for 115 h and the side reaction heat is beyond 320,000 J.The continuous self-excitation behavior inside the battery is attributed to the interaction between the highly oxidized cathode and the solvent,which leads to the dissolution of metal ions.The dissolved metal ions destroy the SEI(solid electrolyte interphase)film on the surface of the deposited Li of anode,which induces the thermal reaction between lithium metal and the solvent.The interaction between cathode,the deposited Li of anode,and solvent promotes the temperature of the battery to rise slowly.When the temperature of the battery reaches more than 60℃,the reaction between lithium me

关 键 词：Lithium ion battery Step overcharge SELF-HEATING Boundary Heat generation Amount of lithium 

分 类 号：TM912[电气工程—电力电子与电力传动]