基于时变流体温度的锂离子电池组传热分析

针对板式液体热管理系统,以软包装三元正极材料锂离子单体电池及电池模组为研究对象,建立单体和整包电池的传热计算模型。基于整包电池模型,分析恒定和时变流体温度对电池模组传热特性的影响。电池包中心或边缘处模组换热条件的差异,对冷却的最高温度和加热的最低温度影响甚微,对最大温差影响不明显。流体恒温的假设在传热计算时会高估系统对模组温度最值的影响;在散热计算时会低估对模组最大温差的影响。在25℃下以1 C放电,线性、指数型流体温升模型最高温度分别比恒温模型高3.34℃和2.54℃;在-10℃下以25℃的流体对电池进行加热,线性、指数型流体温升模型最低温度分别比恒温模型低4.06℃和4.36℃。

Heat transfer analysis for Li-ion batteries based on time dependent fluid temperature

Aimed at the plate liquid cooling thermal management system of electric vehicle,a soft-packed ternary cathode material Li-ion battery and the whole pack were researched by establishing single battery and the whole pack thermal models.The battery module’s thermal behavior changed with constant or time dependent fluid temperature was numerically studied relying on the whole pack model.It was found that:the difference of the heat transfer conditions for each module had little effects on the maximum temperature(when cooling)and minimum temperature(when heating);besides,the maximum temperature difference changed marginally.In the heat transfer calculation,the assumption of constant fluid temperature would overestimate the influence of the system on the maximum temperature of the module.When the discharge rate was 1 C at 25℃,the maximum temperature of linear and exponential model was 3.34℃and 2.54℃higher than that of constant one.when the battery was heated at-10℃with fluid temperature at 25℃,the minimum temperature of linear and exponential model was 4.06℃and 4.36℃lower than that of constant one.