方形硬壳锂离子动力电池的热物性参数

Thermal properties of hard cased lithium-ion power battery

针对现有锂离子电池热物性参数获取手段的缺陷,以方形硬壳锂离子电池为对象,进行热物性参数研究。基于体积平均法计算,得到电池的等效密度2218 kg/m3,等效比热容1060 J/(kg?℃)。通过模拟稳态平板法测试导热系数的边界条件,计算得到50 A?h硬壳锂离子电池3个方向的等效导热系数分别为高度方向17.2 W/(m?℃),厚度方向5.3 W/(m?℃)和长度方向23.4 W/(m?℃)。将电池结构离散为独立的热阻单元,建立热阻的热网格模型,基于基尔霍夫节点电流法,建立电路对应的线性方程组,求解得到电池的等效热阻和等效导热系数,结果表明,热网格模型法获得的导热系数值与仿真法误差小于2%。

The thermal properties of hard cased lithium-ion power battery was investigated.Firstly,the equivalent density of 2218 kg/m3 and equivalent specific heat of 1060 J/(kg·℃)were got according to average volume method.Then,through modeling the boundary conditions of thermal conductivity test,the height conductivity of 17.2 W/(m·℃),the thickness conductivity of 5.3 W/(m·℃)and the length conductivity of 23.4 W/(m·℃)are obtained,respectively.Finally,the thermal network model was set up by discretizing the hard-cased lithium-ion battery structure to resistance units.The Via Kirchhoff current law,linear equations of the circuit network were established,and then were solved to get equivalent thermal resistance and equivalent thermal conductivity.The results show that the error between thermal conductivities obtained by modeling method and by thermal network method is less than 2%.