轴向压缩下圆柱形动力锂离子电池的性能

Performance of Cylindrical Power Lithium-Ion Battery under Axial Compression

动力电池的安全问题制约了电动汽车的推广和发展,轴向压缩是锂离子电池的一种重要的破坏工况。通过实验方法,研究了18650锂离子电池在轴向压缩载荷下的安全性能,探讨了荷电状态分别为60%、80%、100%时电池的载荷、电压、温度的变化特征,分析了轴向压缩载荷下电池的失效过程。研究表明:轴向压缩过程中电压均出现特有的台阶式下降,极限载荷和温度骤升几乎同时发生;电池正极的凹槽结构诱导电池在靠近正极的侧面破裂。对比轴向压缩实验和径向平板压缩实验发现,动力电池轴向压缩热失控程度弱于径向平板压缩。

The safety of power batteries have always restricted the promotion and development of electric vehicles.The axial compression of batteries is an important issue leading to damage.The safety performance of 18650 lithium-ion battery under axial compression was studied by experiments.The characters of load,voltage and temperature of batteries with state of charge of 60%,80%,and 100%were discussed,and the failure process of the battery under axial compression was analyzed.It was found that the voltage during the axial compression process showed a unique stepped drop,the maximum load and a sudden temperature increase occurred almost simultaneously;the local groove structure of the positive induced the battery to rupture near the positive.Comparing the batteries in axial compression with the batteries of the radial twoplate compression,it was found that the thermal runaway of power battery in axial compression is weaker than that in radial two-plate compression.