Large-format lithium-ion(Li-ion)batteries with high energy density for electric vehicles are prone to thermal runaway(or even explosion)under abusive conditions.In this study,overcharge induced explo-sion behaviors of large-format Li-ion pouch cells with Li[Ni0.8Co0.1Mn0.1]O2 cathode at different current rates(C-rates)(0.5C,1C,2C)were investigated.The explosion characteristics of the cells were elucidated by discussing the evolution of the cell voltage,the surface temperature and the shock wave pressure.Generally,the whole overcharge process could be divided into four stages according to the evolution of several key parameters and the overcharge behaviors;the overcharge C-rate has a great influence on cells'thermal behaviors.The experimental results showed that the thermal runaway process of Li-ion cells caused by overcharging consisted of two kinds of explosions,physical explosion and chemical explosion.The existence of observable negative pressure zone in the pressure curves indicated that the Li-ion cells are not a self-supplying oxygen system during the explosion.Further,the explosion dynamics parameters were matched.An explosion TNT-equivalent conversion strategy that depended on the pres-sure of the shock wave was utilized to evaluate the released energy and its hazards.In addition,with respect to the overcharge of Li-ion pouch cells,a safety assessment method and a safety management method were proposed based on the explosion behaviors.From the perspective of battery safety,this study is of great significance for the safety design of Li-ion cells and can provide guidance for engineers to optimize the safety function of battery packs.

Tongxin Shan;Zhenpo Wang;Xiaoqing Zhu;Hsin Wang;Yangjie Zhou;Yituo Wang;Jinghan Zhang;Zhiwei Sun

National Engineering Research Center of Electric Vehicles,Beijing Institute of Technology,Beijing 100081,China;Materials Science and Technology Division,Oak Ridge National Laboratory,Oak Ridge,TN 37831,United States;State-assigned Electric Vehicle Power Battery Testing Center,China North Vehicle Research Institute,Beijing 100072,China

能源化学

[1]Tongxin Shan;Zhenpo Wang;Xiaoqing Zhu;Hsin Wang;Yangjie Zhou;Yituo Wang;Jinghan Zhang;Zhiwei Sun-.Explosion behavior investigation and safety assessment of large-format lithium-ion pouch cells)[J].能源化学,2022(09):241-257

abusive,overcharge

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