Research On Topology Optimization Of Heat Dissipation Structure For Electric Vehicle Lithium Battery

Lithium battery occupies a dominant position in the electric vehicle power battery market due to its advantages of high voltage,small size,high energy density,good cycle performance and no memory effect.As the only power source for electric vehicles,its performance has an important impact on the performance of the vehicle However,the performance of lithium batteries is greatly affected by changes of the temperature.Too high temperature may even cause battery failure.After comparing and analyzing the current heat dissipation structure of lithium batteries of electric vehicles,this paper adopts the topology optimization method to design and study the heat dissipation structure of lithium batteries.The main research contents of this article are as follows:1.The heat dissipation structure model of lithium battery and topology optimization theory are studied.The theoretical framework of topology optimization design of lithium battery heat dissipation structure is constructed,and the design variables are optimized to improve the accuracy of topology optimization results.2.Under different objective functions,the topology optimization design results of the lithium battery heat dissipation structure under different fluid volume fractions(V_f)are analyzed respectively,and the influence of V_f on the topology optimization design results is studyed.The results show that under different objective functions,the value of the objective function in the design area of the heat dissipation structure decreases with the increase of V_f,but the change rule of the flow channel in the heat dissipation structure is different:when the objective function is the lowest average temperature of the solid area in the design area,the shapes of the flow channel in the heat dissipation structure are quite differenct under different V_f;when the objective function is the lowest average temperature in the design area,the shape of the flow channel in the heat dissipation structure is relatively fixed under different V_f.3.Under the condition that V_f is 60%,under different objective functions,the topological optimization design results of the lithium battery heat dissipation structure under different Re are analyzed and compared,and the effects of Re and the objective function on the topology optimization design results are studied.The results show that when the objective function is the lowest average temperature in the design area,the flow channel structure in the heat dissipation structure designed under different Re is more stable;when the objective function is the lowest average temperature of the solid area in the design area,the shape of the flow channel in the heat dissipation structure under different Re is quite different;under different objective functions,the average temperature,the average temperature in the solid area,and the highest temperature and the maximum temperature difference in the heat dissipation structure design area decrease as Re increases.4.The average temperature and the average temperature of the solid area in the design area of the lithium battery heat dissipation topology optimization results under different objective functions are compared and analyzed.The results show that when Re ≤250,the average temperature and the average temperature of the solid region are lower in the design region when the target function is the lowest average temperature of the solid region in the design region;when Re≥500,the average temperature and the average temperature of the solid region are lower in the design region when the target function is the lowest average temperature of the design region.Therefore,when Re ≤250,it is more reasonable to choose the lowest average temperature of the solid area in the design area as the objective function,while when Re≥500,it is more reasonable to choose the lowest average temperature of the design area as the objective function.5.Based on the heat dissipation structure topology optimization research results,a new lithium battery heat dissipation structure is designed,and the new heat dissipation structure and the existing heat dissipation structure are simulated under the same working conditions.The results showed that:compared with the existing heat dissipation structure,the amount of fluid heat exchange of the new heat dissipation structure in the unit time has been greatly improved with an average increase of 144.25%under the same pin and an average increase of 249.5%under the same uin.Therefore,the new heat dissipation structure obtained by topology optimization design has better heat dissipation performance..