触发位置对锂离子电池模组热扩散特性的影响

Influence of triggering position on thermal runaway propagation characteristics of lithium-ion battery module

针对锂离子电池热扩散问题,以18650三元锂离子电池为研究对象,搭建了模组的热扩散模型,研究了模组中不同位置单体触发热失控后对整个模组热扩散的影响。基于锂离子电池热失控反应机理和热传导机理建立了单体电池在绝热条件下的热失控模型,并通过设计相应试验验证模型的准确性,仿真结果与试验结果吻合较好。以单体电池热失控模型为基础,搭建模组热扩散模型,研究了模组中不同位置单体触发热失控对模组热扩散的影响。结果表明:中心位置单体触发热失控,热失控行为呈放射状向周围扩散,且每次都是两个单体电池一起发生热失控,在40 s左右,模组一侧的电池全部达到热失控触发温度;边缘位置单体触发热失控,热失控行为依次向周围扩散,且每次只有一个单体发生热失控,大约50 s的时间,模组一侧的电池全部达到热失控触发温度。最后,基于热扩散模型研究了不同隔热材料对模组热扩散速率延缓的作用。

Aiming at studying the thermal runaway propagation issues,a thermal runaway propagation model was built with 18650 ternary lithium-ion battery,and the influence of different triggering position on the thermal runaway propagation behavior was studied.Firstly,a thermal runaway model under the adiabatic condition was established based on the thermal runaway reaction mechanism and heat conduction mechanism.Then,the related experiments were designed to verify the accuracy of the thermal runaway model,and the simulation results were in good agreement with the experimental results.Lastly,a thermal runaway propagation model was established based on the thermal runaway model of the single battery.Based on the model,the influence of the thermal runaway triggering position on the thermal runaway propagation behavior was studied.The results show that:with the battery being triggered at the central position of the module,the thermal runaway propagates radially to the surroundings with two batteries occurring thermal runaway at the same time,and all the batteries on one side of the module reach the thermal runaway temperature in about forty seconds;with the battery at the edge position of the module being triggered,the thermal runaway propagates to the surroundings with one battery each time,and all the batteries on one side of the module reach the thermal runaway temperature after about fifty seconds.Finally,the effect of different thermal insulation materials on the module thermal runaway propagation was studied based on the thermal runaway propagation model.