Research On Ithium Battery Thermal Management System For Electric Vehicle

With the electric vehicles developing rapidly,power battery pack,as the core components of electric vehicles,has some problems exposed constantly.The temperature of batteries determines the cruising radius of the electric vehicle and the service life of the battery pack,even directly related to the safety of electric vehicle users.The scientific and reasonable thermal management system is used to control the battery temperature within a safe and reasonable temperature range,which could improve the performance of the power battery and extend service life.More importantly,it can guarantee the safety of battery in the process of using electric vehicles.Therefore,it is significance of doing research on thermal management of power battery packs.In this paper,after an analysis in the heat generation mechanism of the power battery and the research progress of the battery thermal management system,the heat production of TAFEL—LAE895 ternary lithium battery has been calculated theoretically at different discharging rates.A thermal management model based on paraffin graphite composites was designed to simulate the paraffin melting process and the battery surface temperature distribution by Fluent.A charging and discharging experimental platform for power battery has been built,which is used to research battery surface temperature rise and uniformity by the experiments at different rates,this paper emphasizes the temperature controlling effect of the system based on different graphite content of composite phase change materials combine with semiconductor refrigeration technology.The experimental results show that with the increase of charging and discharging rates,surface temperature rising rate and the maximum temperature of the battery increase.And the content of expanded graphite can improve the thermal conductivity of the PCM,reduce the fluidity of paraffin after heat absorption and melting,and improve its thermal management performance.Combining composite phase change materials with semiconductor refrigeration technology,the performance of thermal management system has great improved,and the temperature controlling effect becomes better obviously.Working in the condition of high discharge rate,the highest surface temperature of battery has been controlled within 50℃ by the system.Meanwhile,the temperature uniformity between single battery is reduced which has been controlled within 3 ℃.