Abstract The mechanical and failure behaviors of individual 18,650 cylindrical battery have been studied in many papers recently, showing that the internal short-circuit of the battery can be induced by the mechanical load. In practice, the cylindrical batteries mostly work in a packed way and there is little research on the packed batteries. In the present paper, failure behaviors of packed batteries under both quasi-static compression and dynamic collision are investigated by tests. It is shown that the deformation of the packed batteries is very different from those of the individual ones. The failure of the packed batteries is caused by the nonuniform deformation within each battery, which creates vulnerable areas near the gap among batteries. Besides, it is found that the packed batteries under impact collision undergo distinguishing behaviors from those under quasi-static compression. Under quasi-static situations, the packed batteries deform uniformly and the failure batteries distribute randomly. However, under dynamic impact, the packed batteries are crushed row by row with force concentrating at some certain rows, which results in the heavier damage of the batteries under the same crushing displacement, meaning a higher failure risk. Then numerical simulations are employed to deeply investigate the dynamic mechanism of the packed batteries. Four types of failure behaviors are discovered for the packed batteries under dynamic collision, which are related to the stress wave propagation and give a good explanation on the complex dependence of the failure displacement of the packed batteries on the crushing speed. The results indicate that the crushing velocity dominates the failure behavior of the packed batteries rather than the crushing energy. The failure displacement of the battery pack will dramatically decrease once the crushing velocity larger than 20 m/s. More attention should be drawn on the dynamic safety of the packed batteries and the related safety standards also need to consider the complex dynamic collision. All the investigations may provide a basic foundation for the safety protection research of the packed batteries, which are helpful for electric vehicle industry and other structures with packed batteries.

中文翻译：

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电池组的破碎行为与失效

摘要 近来多篇论文研究了单个18650圆柱电池的机械和失效行为，表明电池内部短路可由机械负载引起。在实践中，圆柱电池多采用打包方式工作，对打包电池的研究较少。本文通过试验研究了电池组在准静态压缩和动态碰撞下的失效行为。结果表明，电池组的变形与单个电池的变形有很大不同。电池组的失效是由于每个电池内部变形不均匀，在电池间隙附近产生易损区域。除了，发现冲击碰撞下的电池组与准静态压缩下的电池组有明显的区别。在准静态情况下，电池组变形均匀，失效电池随机分布。然而，在动态冲击下，电池组被逐行挤压，力集中在某些行，在相同的挤压位移下，电池的损坏更大，意味着更高的故障风险。然后通过数值模拟深入研究了电池组的动力学机制。动态碰撞下电池组发现四种失效行为，与应力波传播有关，很好地解释了电池组失效位移对破碎速度的复杂依赖性。结果表明，破碎速度主导着电池组的失效行为，而不是破碎能量。一旦破碎速度大于20m/s，电池组的失效位移将急剧下降。电池组的动态安全性需要更多关注，相关安全标准也需要考虑复杂的动态碰撞。上述研究可为电池组的安全防护研究提供基础，对电动汽车行业及其他带电池组结构的结构有帮助。结果表明，破碎速度主导着电池组的失效行为，而不是破碎能量。一旦破碎速度大于20m/s，电池组的失效位移将急剧下降。电池组的动态安全性需要更多关注，相关安全标准也需要考虑复杂的动态碰撞。上述研究可为电池组的安全防护研究提供基础，对电动汽车行业及其他带电池组结构的结构有帮助。结果表明，破碎速度主导着电池组的失效行为，而不是破碎能量。一旦破碎速度大于20m/s，电池组的失效位移将急剧下降。电池组的动态安全性需要更多关注，相关安全标准也需要考虑复杂的动态碰撞。上述研究可为电池组的安全防护研究提供基础，对电动汽车行业及其他带电池组结构的结构有帮助。电池组的动态安全性需要更多关注，相关安全标准也需要考虑复杂的动态碰撞。上述研究可为电池组的安全防护研究提供基础，对电动汽车行业及其他带电池组结构的结构有帮助。电池组的动态安全性需要更多关注，相关安全标准也需要考虑复杂的动态碰撞。上述研究可为电池组的安全防护研究提供基础，对电动汽车行业及其他带电池组结构的结构有帮助。