电动汽车电池温控的热负荷数值分析

Numerical analysis on thermal load of battery temperature control for electric vehicles

为了开发高效节能的电动汽车电池热管理系统,通过建立电池发热模型,对电池温控的热负荷进行理论计算,并分析散/预热负荷、散/预热临界温度、临界时间与车速、环境温度的关系。结果表明:平均车速越快,启动电池散热系统的临界环境温度越低;环境温度越高,启动散热系统的临界时间越短。平均车速为60 km/h时,散热负荷约为0.18 kW;平均车速为120 km/h时,散热负荷约为3.0kW。启动散热系统的临界环境温度为22℃,当环境温度为35℃时,散热临界时间为0.43 h。环境温度越低,预热负荷越大,当环境温度为-20℃时,在15 min内将电池从环境温度加热到5℃的加热负荷为5.3 kW。车辆行驶平均车速在120 km/h时电池温升约23℃,60 km/h时电池温升约6℃,平均车速较低时,需要提高预热温度以满足电池高效运行所需的温度范围。

In order to develop high efficient battery thermal management system,the thermal load of battery temperature control is calculated theoretically by a heating generation model.The relationships between the loads,critical temperature,critical time for cooling/preheating,and vehicle speed ambient temperature are analyzed.The results show that the higher the average vehicle speed is,the lower the critical ambient temperature for battery cooling system to start is;the higher the ambient temperature is,the shorter the critical time for battery cooling system to start is.When the average vehicle speed is 60 km/h,the cooling load is about 0.18 kW;when the average vehicle speed is120 km/h,the cooling load is about 3.0kW.The critical ambient temperature for cooling system to start is 22℃.Furthermore,when the ambient temperature is 35℃,the critical time for cooling system to start is around 0.43 h.In addition,the lower the ambient temperature is,the more the preheating load is.At ambient temperature of-20 ℃,it will take heating load of 5.3 kW to heat the battery from ambient temperature to 5 ℃.When the average vehicle speed is 120 km/h or 60 km/h,the battery temperature increases by 23℃ and 6℃respectively,which means that it is better to increase the preheating temperature to a higher temperature for the efficient operation of batteries when the average vehi-cle speed is low.