方形锂离子电池热应力的数学分析和数值模拟

Mathematical analysis and numerical simulation for thermo-stress in a square lithium-ion battery

锂离子电池在充放电过程中,温度升高产生热应力,对电池性能有一定的影响。本文通过数学求解和仿真的方法,给出了方形锂离子电池温度场和热应力场,定量分析了相关影响因素。结果表明:电池的最高温度出现在几何中心;最大温差与生热速率和电池尺寸的平方呈正比。电池中心区域热膨胀受压应力,侧边区域受拉应力,侧边中心处出现热应力集中。最大拉应力约为最大压应力的2倍。

The temperature rise and thermal stress in lithium-ion battery charging and discharging processes may affect battery performances. This paper gives the temperature field and thermal stress field for a square lithium-ion battery using theoretical calculation and simulation method, and analyzes relationship factors. The results show that the highest temperature in the geometric center increases linearly with the heat generation rate. The maximum temperature difference increases linearly the square of battery sizes. The battery center area, the high-temperature region, has compressive stress; battery side center has tensile stress. Thermal stress concentration occurs at the center of the sides. The maximum compressive stress is 2 times the maximum compressive stress.