不同荷电状态锂电池模组热扩散特性的研究

Research on thermal diffusion characteristics of lithium-ion battery module under different state of charge

随着动力锂电池技术的快速发展,电池比能量得以不断提升。然而外部滥用条件可能会引发电池热失控,释放更多的能量,产生更大的破坏力。以不同荷电状态的某三元锂电池模组为研究对象,对其进行挤压触发的热扩散试验。通过对各试验组样品第1颗电芯失效时的热失控表现、最大挤压力、最高温度等关键参数进行分析和比对,发现荷电状态的高低对锂电池模组热扩散行为有显著影响。在高荷电状态下,模组受挤压时靠近挤压点的电芯会先发生剧烈的热失控,进而导致相邻电芯依次热失控。在低荷电状态下,靠近挤压点的电芯不会发生剧烈的燃烧、爆炸现象,也不会影响相邻电芯造成热扩散。文中的研究成果可以为该型三元锂电池在运输、存储过程中安全荷电状态限值的确定提供参考。

With rapid development of power lithium-ion battery,the specific energy of battery is continuous improved.The subsequent problem is that when the external abuse conditions cause the battery thermal runaway,it will release more energy and produce greater destructive power.In this paper,ternary lithium battery under different state of charge were taken as research object,and crush triggered thermal diffusion test were carried out.Through the analysis of the key parameters such as the failure mode of the first cell,the maximum extrusion force and the maximum temperature,it was found that the SOC has a significant impact on the thermal diffusion behavior of lithium battery module.In the state of high charge,when the module is crushed,cell near the crush point will first have severe thermal runaway,which will cause the thermal runaway of adjacent cells in turn.In the state of low charge,cell near the crush point will not have violent combustion and explosion,nor will it affect the adjacent cells and cause thermal diffusion.The research results of this paper can provide reference data for the determination of safe SOC threshold in the process of transportation and storage.