Structural Design And Heat Dissipation Optimization Of Lithium-ion Battery Pack

The development of modern industry has made energy depletion increasingly serious,and the energy crisis and environmental pollution are serious.Under the national call and subsidy policy,the electric vehicle industry has ushered in the spring of development.As the key technologies of batteries have been conquered in recent years,as the only energy source of pure electric vehicles,the performance of power batteries directly determines the performance of electric vehicles.The performance of lithium-ion batteries is closely related to temperature.Too high,too low or uneven distribution will have a great impact on it.Therefore,the research of battery thermal management has important practical significance.This article mainly does the following work:1)A brief overview of the structure and working principle of lithium-ion batteries,the characteristics of lithium-ion batteries,and the main classification of lithium-ion batteries.It is clear that the heat production of lithium ion batteries mainly includes reaction heat,internal resistance heat and side reaction heat,and dissipates heat in the form of heat conduction,heat convection and heat radiation.2)Obtain the internal resistance and temperature entropy coefficient of the battery through experiments,and compile the udf of the battery heat generation to establish the battery heat generation model.The fluent is used to simulate the air field of the single cell,calculate its temperature change under different discharge currents,and compare the simulation results with the experimental data.The temperature rise characteristics of the numerical simulation are basically consistent with the experimental temperature rise characteristics,and the agreement is good To verify the rationality of the established battery heat generation model.3)Based on the battery thermal characteristics experiment,the temperature characteristics of lithium-ion battery modules are studied.Establish a three-dimensional model of the battery module.The battery in the module is discharged with a current of 6A,and the heat is dissipated at a certain wind speed.Through the computational fluid dynamics method(CFD)to study the battery module of different structure forms,so as to obtain the structure with the best cooling effect.The results show that the cooling effect of modules with different structures is different,and the reasonable choice of structure can obviously enhance the heat dissipation of battery modules.Then analyze the structure of the battery module,change its inlet and outlet angle,and the size of the side margin to improve the heat dissipation performance of the battery module,and the cooling effect is obvious.Then explore the heat dissipation effect of the battery spacing and air flow rate in the module,and further achieve the purpose of cooling.Finally,the multi-objective optimization method was used to optimize the structure of the battery module,and the optimization scheme of the experimental design point ex 15 was finally determined to have the best temperature difference of 3.94K and the highest temperature of 306.97K.