动力电池包局部复式模组热均匀性分析

Thermal Uniformity Analysis of Local Duplex Module for Power Battery Packs

乘用车动力电池包的模组布置方式通常具有单层布置、复式布置和局部复式布置3种不同的形式。局部复式布置结合了其他两种方式的特点,应用较为广泛。然而,通过对电动汽车火灾事故的研究发现,采用局部复式布置的电池包在自燃事故中所占比例较高,这表明该布置方式可能会对电池模组的热均匀性产生不利影响。鉴于此,本文选取了一款采用局部复式布置的电动汽车电池包作为研究对象,建立了电池包三维数值模型,并通过实验数据与仿真结果进行比较,验证了模型的准确性。利用经验证的模型,通过数值计算方法分析了电池包在快充及3种放电速率下的模组温度分布特征,揭示了局部复式布置模组在这些工况下的热均匀性,尤其是局部复式模组中双层模组的温度差异比单层模组更大。此外,探讨了冷却液入口温度和流速分别对模组热均匀性的影响。研究发现:试图降低冷却液入口温度来改善模组热均匀性的效果有限;而增大冷却液入口流速只能在高放电速率工况下减小模组温度差异,在低放电速率工况下的影响不明显。本研究为局部复式模组的电池热管理系统开发和设计提供了有意义的参考。

The module arrangement of passenger car power battery packs usually has three different forms:single-layer arrangement,duplex arrangement and local duplex arrangement.The local duplex arrangement,which combines the characteristics of the other two methods,is more widely used.However,the study of electric vehicle fire accidents shows that battery packs with local duplex arrangement account for a higher proportion of spontaneous combustion accidents,which indicates that this arrangement may adversely affect the thermal uniformity of the battery module.In view of this,in this paper taking an electric vehicle battery pack with local duplex arrangement as the research object,a three-dimensional numerical model of the battery pack is established and the accuracy of the model is verified by comparing the experimental data with the simulation results.Using the validated model,the module temperature distribution characteristics of the battery pack under fast charging and three discharge rates are analyzed by numerical calculation methods,revealing the thermal uniformity of the local duplex arrangement of the modules under these conditions,especially the with the temperature difference of the double-layer module in the local duplex module larger than that of the single-layer module.In addition,the effect of coolant inlet temperature and flow rate on the thermal uniformity of the modules is explored respectively.It is found that attempting to reduce the coolant inlet temperature to improve the thermal uniformity of the module has limited effect,while increasing the coolant inlet flow rate can only reduce the temperature difference of the module under high discharge rate conditions,without obvious effect under low discharge rate conditions.This study provides a meaningful reference for the development and design of the battery thermal management system with local duplex modules.