基于COMSOL的锂离子电池热失控仿真研究

Thermal Runaway Simulation of Lithium Batteries Based on COMSOL

为研究锂离子电池的热失控机理,减少锂电池的因高温引起的热失控事故,借助COMSOL Mul-tiphysics 6.1软件对三元锂离子电池建立热滥用引起的热失控三维模型,对不同高温环境下的热失控进行数值模拟。通过将电池处于不同加热环境、不同初始温度及不同传热系数等工况下,分析锂电池内部的热失控反应。结果表明:不同环境温度工况下,温度越高,热失控温度峰值越高,出现热失控时刻越早;不同传热系数工况下,传热系数越大,热失控时刻越早,达到峰值后温度下降梯度越大;发现在热失控过程中,相较于正负极材料和电解液,SEI膜的分解更易受环境温度的影响。

In order to study the thermal runaway mechanism of lithium-ion batteries and reduce the thermal runaway accidents caused by high temperatures in lithium batteries, a three-dimensional model of thermal runaway caused by thermal abuse was established on ternary lithium-ion batteries with the help of COMSOL Multiphysics 6.1 software, and the thermal runaway in different high-temperature environments was numerically simulated. The thermal runaway reaction inside the lithium battery was analyzed by subjecting the battery to different heating environments, dif-ferent initial temperatures and different heat transfer coefficients. The results show that the higher the temperature, the higher the peak temperature of thermal runaway, and the earlier the thermal runaway moment occurs. Under different heat transfer coefficient conditions, the larger the heat transfer heat coefficient, the earlier the thermal runaway time, and the greater the temperature drop gradient after reaching the peak. It is found that in the process of thermal runaway, the de-composition of SEI membranes is more susceptible to the influence of ambient temperature than that of positive and negative electrode materials and electrolytes.