Analysis And Optimization Of Heat Dissipation Performance Of Power Battery Module Liquid Cooling System

Based on the demand for solving the dependence on oil and reducing carbon emissions,new energy electric vehicles have developed rapidly.With the large-capacity/high-energy-density power battery and high-voltage fast charging technology,they are continuously applied to more and more models.The direct consequence is that the rapid heat accumulation of the battery core body caused by the ultra-high current in a short time,the safety performance is significantly reduced,the service life is greatly shortened,and serious accidents such as spontaneous combustion and explosion will occur.Therefore,it is of great significance to study the battery cooling system.In this paper,with the help of CFD simulation technology,the simulation models of different heat dissipation schemes are established,and the comparative analysis confirms the advantages of the liquid cooling plate cooling scheme in terms of temperature control.Under the same discharge rate,the temperature difference of the liquid cooling plate liquid cooling method is higher than that of the serpentine pipeline liquid.The cooling method decreased by 81.7%;compared with the straight tube cooling method,it decreased by 54.9%.Change the factors that affect the temperature field of the module to obtain the temperature field distribution of the module under different conditions.Increasing the coolant flow rate can reduce the temperature difference and maximum temperature of the module.This trend gradually slows down as the coolant flow rate continues to increase;Reducing the inlet temperature of the coolant can significantly reduce the maximum temperature of the module,but the effect on the temperature difference can be neglected;changing the inlet and outlet settings of the module flow channel can significantly improve the temperature field distribution of the module,and has better control.Temperature effect;increasing the thermal conductivity of the battery will cause the temperature difference between the module and the maximum temperature to decrease synchronously.When the thermal conductivity reaches a certain range,the temperature control effect begins to weaken and eventually stabilizes.This paper optimizes the design of the cooling channel based on the optimal design method of establishing an approximate model,and uses the NCGA multi-objective optimization genetic algorithm to optimize the variable size.By comparing the CFD simulation results with the optimal solution of the approximate model,the fitting accuracy of the approximate model is verified.For the liquid-cooled plate model,under the condition that the pressure difference only increased by 5.3%,the temperature difference decreased by 14.7%,and the temperature difference of the module was controlled within 5°C at 2C discharge rate,and the optimization effect was significant.In this paper,the model design of the heat dissipation scheme of the variable cross-section flow channel is introduced,and the concept of shrinkage rate isintroduced.Comparative analysis shows that the design of the variable cross-section flow channel is superior to the equal cross-section method in terms of temperature control,and as the shrinkage rate increases,the average temperature effect more obvious.