Analysis Of Influence Factors On Cooling Of Battery Liquid Cooling System In High Power Charging State

With the continuous development of the economy,the mileage of pure electric passenger cars has continuously increased.In order to adapt to this development trend,high-power charging has become an important form of electric vehicle charging in the future.However,high-power charging will bring a series of challenges to vehicle design and power battery performance.During the high-power charging process,the heat generation of the power battery is significantly increased,resulting in a significant increase in battery temperature and serious safety risks.Therefore,it is necessary to study the heat generation characteristics of the battery under high-power charging conditions,establish a battery heat generation model to accurately estimate the battery temperature,and provide theoretical guidance for the design of the battery thermal management system.In this paper,a large-capacity 30Ah lithium iron phosphate?LiFePO₄,LFP?soft pack battery is used as the research object.First perform performance test and parameter estimation on it,and then explore the heat generation characteristics of LFP batteries under different charging rates through battery charging temperature rise experiments,and analyze the heat production rules of LFP batteries under high power charging conditions.Based on the experiment,a simulation model was built using COMSOL Multiphysics software to simulate the temperature change of the battery under high power charging conditions.Subsequently,the accuracy of the heat generation model was verified using the temperature rise obtained from the experiment.Based on this,a liquid cooling model for the battery pack is constructed,and the influence factors of the battery pack cooling system under different charging rates are analyzed,mainly considering the influence of the coolant inlet flow rate and the cooling channel structure on the battery pack temperature rise.The results show that high-power charging condition can effectively reduce the charging time of the battery,but the battery is significantly increased heat production,accelerating the rate of temperature rise of the battery.Therefore,the design of the battery pack thermal management system is very necessary under high power charging conditions.At the same time,the simulation results of the battery pack cooling system can show that increasing the coolant flow rate within a certain range can effectively improve the cooling effect and reduce the highest temperature rise of the battery pack,and the optimal coolant flow rate varies with the charge rate.Changing the cooling channel size has a certain effect on the cooling effect of the battery pack,which can improve the temperature uniformity of the battery pack,increasing the size can improve the temperature uniformity of the battery pack.By analyzing the cooling effect of the liquid cooling system on the battery pack under high power charging conditions,it is proved that the cooling structure studied in this paper can significantly reduce the maximum temperature of the battery pack under high power charging conditions,and the temperature uniformity of the battery pack is significantly improved.The work done in this paper can provide reference for the design of battery thermal management system under high power charging conditions.