高容量商用方形锂离子电池外部短路行为  

External short-circuit behaviors of commercial prismatic lithium-ion batteries with high capacity

作　　者：刘英博 周仕贤 李艳旭 曹佩 王宁 张博文 阴育新 陈超 LIU Yingbo;ZHOU Shixian;LI Yanxu;CAO Pei;WANG Ning;ZHANG Bowen;YIN Yuxin;CHEN Chao(Tianjin Lishen New Energy Technology Co.,Ltd.,Tianjin,300384,China)

机构地区：[1]天津力神新能源科技有限公司,天津300384

出　　处：《电池工业》2024年第4期169-173,183,共6页Chinese Battery Industry

摘　　要：外部短路是锂离子电池应用中的主要失效模式之一。外部短路会导致锂离子电池在较短的时间内产生较大的短路电流,带来热失控风险。当前锂离子电池外部短路的研究主要集中在小容量的电池上,但是不同容量的电池会在短路持续时间、短路温升以及温升滞后等行为上产生明显的差异。本文以51 Ah三元(NCM622)商用方形锂离子电池为研究对象,探究了锂离子电池在不同电阻下的短路行为,并关注了温度特征。研究表明,锂离子电池短路放电容量、短路电流对最高温度具有决定作用。高容量方形锂离子电池产热速率与导热速率的不平衡导致锂离子电池短路过程温升的滞后性。对短路后的电池进行拆解,电池内部发生了正极对隔膜的热粘接以及正极析铜现象,外部短路对锂离子电池产生了不可逆的破坏。基于锂离子电池在短路过程中电压、电流、温度的变化,提出锂离子电池短路机制。External short-circuit(ESC)is one of the main sources for battery failures,which can cause large current value in short period,increasing the risk of thermal runaway.However,current study mainly focuses on the ESC behaviors of Lithium-ion batteries(LIBs)with less capacity,which is significantly distinguished form that of LIBs with high capacity.Herein,ESC experiments were conducted under various resistances to investigate short circuit behaviors of commercial prismatic LIBs with 51 Ah and based on NCM622 cathode,and especially for the evolution of temperature.The results indicate the discharge capacity and current value are both contributing to temperature rise.Furthermore,heat conductivity and temperature rise show unbalance relation,leading to hysteretic characteristic for high capacity prismatic LIBs.Post-mortem analysis of LIBs after ESC showed that cathode materials peeling off from current collector and cathode materials adhering to separator and copper plating on cathode demonstrated irreversible damage to LIBs.The ESC mechanism was proposed based on the ESC behaviors including the evolution of current,voltage and temperature.

关 键 词：外部短路行为 高容量锂离子电池 温度特征 温升滞后 

分 类 号：TM911.24[电气工程—电力电子与电力传动]