圆柱形动力锂电池传热分析及升温特性

Study on heat transfer and temperature rising characteristic of cylindrical Li-ion battery

动力锂电池的产热功率、物性参数和散热效率对电池的工作性能及安全性具有重要影响。本文分析了26650型磷酸铁锂电池的产热功率和电芯的等效密度、比热容、导热系数等物性参数;采用流体力学软件Fluent模拟电池内部的温度场。结果表明:电芯的轴向导热系数远大于径向(λ轴向=26.96 W·m2·K-1,λ径向=0.98 W·m2·K-1);在空气自然对流下,数值模拟预测电池表面温度值与实验测试结果基本吻合;电池的Tmax随hside或hbottom的增大而减小,增大hside更能提高电池的散热效果。

The heat generation of power Li-ion battery during operation has an important influence on the operating performance and thermal safety of the battery.In this paper,the heat generation power and thermophysical parameters such as equivalent density,specific heat capacity and thermal conductivity were discussed in detail.Also,the temperature field inside the battery was simulated by Fluent.The results indicated:(1)the thermal conductivity of the core in the axial direction of the cylindrical battery(λaxial=26.96 W·m^2·K^-1)is much larger than that of the radial direction(λradial=0.98 W·m^2·K^-1);(2)The surface temperature of the battery predicted by the numerical simulation was consistent with the experimental results under the natural air cooling situation;(3)The T max inside battery decreases with the increase in h side or h bottom,and the enhancement of h side could better improve the heat dissipation of cylindrical battery in comparison with h bottom.