Research On Thermal Management Of Power Battery Based On Phase Change Material And Liquid Cooling Coupling

With the increasing call of energy conservation and environmental protection in the transportation industry,the electric vehicle industry arises at the right moment and develops rapidly.In recent years,the fast charging technology of electric vehicles has become an urgent problem to be solved.As the core component of electric vehicles,the safety and stability of power batteries are affected by temperature.If an effective temperature control scheme can be adopted to take away the heat generated in the process of rapid charging,the safety and stability of electric vehicles will be largely guaranteed.In this paper,the thermal management scheme of phase change material and liquid-cooling coupling is proposed for the high rate rapid charging process of power battery,and its performance is analyzed by simulation.The reaction principle and heat generation mechanism of lithium-ion battery were analyzed,the main thermal physical parameters of battery,PCM and coolant were obtained through calculation,and the theoretical calculation method of the theoretical dosage of coolant and PCM dosage was analyzed,so as to prepare for the subsequent simulation research.The charging process of the three-dimensional battery model was numerically simulated,and literature data was used to verify the accuracy of the simulation model.A twodimensional model of temperature control of phase change materials was established to analyze the effect of different phase change temperatures on temperature control.The threedimensional simulation model of the thermal management system was established,and the typical calculation domains were selected for numerical simulation.The effects of different thermal conductivity and latent heat of phase change materials on the thermal management performance were analyzed.Finally,the whole battery was numerically simulated.In the simulation study of two-dimensional phase change material temperature control,a lower phase change temperature was used to achieve better temperature control effect on the battery.In the subsequent study,22℃ was selected as the phase change temperature.In the simulation study of the three-dimensional computing domain,the results show that the higher the thermal conductivity of PCM is,the lower the maximum temperature of the battery is.However,the advantage of temperature control is not obvious when it increases to a certain value,and the maximum temperature difference inside the battery will increase.The effect of temperature control is also better when phase change materials with higher latent heat are used.According to the battery maximum temperature,maximum temperature difference and the rate of the liquid fraction of phase change materials of simulation results,select the best performance parameters.The whole package model of the thermal management system is numerically simulated to obtain the final temperature control effect.The simulation results show that the maximum temperature of the battery pack is controlled within 45℃,and the liquid content of the phase change material is 0.834.The results are in good agreement with the simulation results of typical working conditions in the calculation domain and meet the requirements of thermal management.