Research on liquid preheating performance for battery thermal management of electric vehicles at low temperature

The discharge efficiency of electric vehicles in extremely cold temperatures (-40 degrees C to -20 degrees C) is greatly reduced, and it often takes a lot of time to warm up the battery when starting. Therefore, the purpose of this study is to rapidly warm up the battery at cold temperatures. In order to judge whether it is rapid preheating, we set 180 s (3 min) as the standard value for the duration of rapid preheating of the battery. We designed six hollow aluminum plates to fit on the sides of the five batteries, and heat transfer fluid (HTF) flows through the hollow aluminum plates to bring heat to the batteries. A three-dimensional computational fluid dynamics (CFD) system was established. By studying the three important parameters of pipe diameter, flow rate, and HTF temperature, it was found that the pipe diameter had no significant effect on battery preheating, and should be selected in conjunction with the flow rate. If the battery is preheated to a temperature of 25 degrees C, the HTF should be higher than 25 degrees C. But the higher the HFT temperature, the greater the temperature difference between the battery packs. The preheating is completed within 180 s, and the optimum temperature of HTF is 30 degrees C.

Automated summary

The purpose of this study is to rapidly warm up the battery at extremely cold temperatures. By using hollow aluminum plates and heat transfer fluid, the heat is transferred to the batteries. The study found that the pipe diameter has no significant effect on battery preheating and should be selected in conjunction with the flow rate. The optimum HTF temperature is 30 degrees C.