Design And Optimization Of Heat Dissipation Structure For Thermal Management System Of Lithium Ion Batteries

With the progress of society,people's demand for automobiles is increasing.The per capita ownership of automobiles is also increasing.At the same time,the environmental problems such as exhaust emissions are becoming more and more serious.Electric vehicle is an effective way to solve environmental problems,but overcoming battery technology is a difficult task.Lithium-ion batteries are widely used because of their long range,safety and reliability.In order to make the battery play a better role,get maximum utilization,and prevent thermal runaway and other safety problems,it is necessary to strictly control the influence of temperature on the battery.Therefore,it is imperative to study the battery thermal management system and design a better heat dissipation structure.Firstly,the heat generation principle,thermal characteristics and heat dissipation principle of the battery are analyzed,and the related factors affecting the heat dissipation of the battery are theoretically studied.The specific control theory of CFD software for thermal analysis simulation is analyzed,and the mechanism of temperature distribution is clarified.The basic physical parameters of batteries are analyzed,and several fixed parameters are determined.The methods of selecting values of thermal conductivity,specific heat capacity and heat generation rate are also set.Then,the simulation analysis of aluminium material and phase change material widely used in heat dissipation structure is carried out.The results show that the heat dissipation structure of aluminium material combined with liquid cooling has better control over the maximum temperature of battery,while the heat dissipation structure of phase change material combined with liquid cooling has better control over temperature uniformity,which lays a foundation for further design of heat dissipation structure.Secondly,the heat dissipation structure of the combination of aluminum plate,phase change material and liquid cooling is designed,and several key factors affecting the heat dissipation results,such as the thickness of aluminum plate,the number of water pipes,thermal conductivity,mass flow rate,phase change temperature and water inlet temperature,are analyzed concretely.The ideal parameters are obtained,and the maximum temperature and maximum temperature difference of the battery can be effectively controlled.Finally,using the orthogonal test method,the orthogonal results are analyzed by range,variance and comprehensive balance method.The significance of the influencing factors and the reasonable optimal value are studied,and the optimal heat dissipation scheme is obtained.Based on the orthogonal test method and the multivariate non-linear regression method,a more ideal temperature value can be obtained.The two optimization methods have their own advantages and are related to each other.They can effectively control the maximum temperature and the maximum temperature difference of batteries,which has a good guiding significance for the design of battery thermal management system.