The fire accidents caused by the thermal runaway of lithium-ion battery has extremely impeded the development of electric vehicles. With the purpose of evaluating the fire hazards of the electric vehicle, a full-scale thermal runaway test of the real lithium-ion battery pack is conducted in this work. The experimental process can be divided into three stages according to the combustion behavior. (1) Thermal runaway of the triggered module was induced and shows transient jet flame; (2) thermal runaway propagated between cells and further resulted in the constant repetition of ignition and re-ignition behavior; (3) the fire extinguish stage, in which the flame was suppressed and released a considerable amount of smoke. It is worth mentioning that it takes 22 s to evolve the triggered thermal runaway event to the worst case that the flame can spread throughout the whole cargo compartment. However, the water cannot directly act on the cells due to the shielding of the pack’s cover in the fire extinguish stage, which greatly limits its cooling effect. The potential flame spread over electric vehicle is observed in this work, which can provide useful guidelines for the safety design of lithium-ion battery system.

中文翻译：

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电动汽车用锂离子电池组燃烧行为的全尺寸实验研究

锂离子电池热失控引发的火灾事故极大地阻碍了电动汽车的发展。为了评估电动汽车的火灾隐患，本文对真实锂离子电池组进行了全尺寸热失控试验。实验过程根据燃烧行为可分为三个阶段。(1) 引发模块热失控，呈现瞬态喷射火焰；(2)热失控在电池间传播，进一步导致点火和复燃行为的不断重复；(3)灭火阶段，火焰被抑制并释放大量烟雾。值得一提的是，触发的热失控事件演变为火焰可以蔓延到整个货舱的最坏情况需要22 s。但是，在灭火阶段，由于包盖的遮挡，水不能直接作用于电池，这极大地限制了其冷却效果。在这项工作中观察到潜在的火焰在电动汽车上蔓延，可以为锂离子电池系统的安全设计提供有用的指导。