Simulation Analysis And Optimization Of Battery Passive Liquid Cooling System Of Electric Vehicle

The issues of battery thermal management of electric vehicle(especially the issues of battery cooling)are always the core part of electric vehicle design and research,well-designed battery cooling system can improve the driving range,service life,power performance,fuel economy and safety of electric vehicle efficiently.Liquid cooling system would be a good choice for battery cooling and have excellent performance,there were many articles about battery active liquid cooling system in the past,but in many working conditions the passive liquid cooling system could be qualified for battery cooling requirement and well-designed battery passive liquid cooling system can have excellent performance.This paper studies the air-liquid heat exchanger and battery pack as a whole to analyze the performance of the whole battery passive liquid cooling system.Firstly,this paper obtained heat generation rate of battery cell under different discharge rate by test,and then verified the reliability of heat generation rate and rationality of 3D model building of battery.Secondly,the 3D model of battery passive liquid cooling system was built.In the process of 3D model building,the air-liquid heat exchanger was regard as porous media to avoid the 3D modeling and mesh generation of its local details,and simultaneously ignored the pump and pipe,which have little influence on the result of simulation analysis,to reduce difficulty of system modeling and computation of simulation.Thirdly the discharge current curve was obtained by simulating software ADVISOR under high speed working condition,to get the heat generation rate of battery and air inlet velocity of air-liquid heat exchanger.The simulation result shows the battery passive liquid cooling system can satisfy the cooling requirement of battery,but there still have room to improve its cooling performance by optimizing the structure of cooling board.Finally,we optimized the structure of cooling board and get a obvious improvement,and then analyzed the influence the outdoor temperature and thermal conductivity of battery on passive liquid cooling system.The result of the whole analysis shows that the battery passive liquid cooling system can still satisfy the cooling requirement of battery when outdoor temperature reaches 37?.