Structure Design And Optimization Of Pure Electric Vehicle Coolant Direct Cooling Of Refrigerant Based On Multiscale Model

In order to reduce or eliminate the consumer's anxiety about the electric vehicle's endurance mileage and speed up the charging rate,it is necessary to develop advanced cooling technology of power battery pack.Therefore,based on the ternary lithium-ion battery used in the electric vehicle produced by Jiangling Group New Energy,.this paper constructs a thermal design model of the direct cooling of refrigerate power battery pack from the multi-scale point of view,and uses it to design and optimize the structure of the battery pack.On the scale of the core,one-dimensional coupled thermal-electrochemistry model and three-dimensional coupled thermal-electrochemistry model of the core of the ternary lithium-ion battery are developed respectively,and they are respectively used to simulate the discharge process of the core.It is found that the one-dimensional coupled thermal-electrochemistry model developed in this paper is closer to the experimental results than the results calculated by the model in the literature.In addition,it also considers the battery tad and current collector of the three-dimensional coupled thermal-electrochemistry model can describe the temporal and spatial information of each physical quantity in the core more specifically.Therefore,the coupled thermal-electrochemistry model developed in this paper can more accurately reveal the thermal mechanism of ternary lithium-ion battery.On the scale of single battery cell,based on the three-dimensional coupled thermal-electrochemistry model,this paper constructs the coupled thermal-electrochemistry model of the ternary lithium-ion battery,deeply discusses the temperature distribution and heat production distribution information of ternary lithium-ion battery in the discharge process,and compares with the experimental results.It is found that the macro output performance predicted by the model of monomer heat generation rate is in a good match with the experimental results,and the model can also be used to calculate the heat generation rate of the single cell.About the scale of battery pack,on the basis of obtaining the monomer heat generation rate of ternary lithium-ion battery,this paper constructs the thermal design model of the refrigerant direct cooling power battery pack,and uses it to design and optimize the battery pack structure.It is found that whether the temperature of the cooling medium flowing into the battery pack is close to its phase change temperature,the climbing rate of the cooling medium in the capillary core,the thickness of the capillary core,its porosity and pore diameter,etc directly determine the performance of temperature equalization in the refrigerantdirect cooling battery pack and whether the whole system can be controlled and the time of controlled state.Therefore,the research results obtained in this paper not only provide important tools or means for the structural design and optimization of the refrigerant direct cooling power battery of electric vehicle,but also hope to greatly improve the cooling performance of the battery pack and ensure the safe and stable operation.