| With the rapid development of new energy vehicles in China,the problem of slow charging speed of electric vehicles is gradually attracting social attention.Fast charging technology can solve this problem,but the heat generated by the battery during rapid charging will seriously affect the life of the battery and even cause safety hazards.Therefore,it is necessary to establish an heat generation model of Li-ion battery,analyze the thermal performance of the battery under fast charging conditions,and the effect of different fast charging methods on the thermal performance of the batteryIn this paper,a commercial ternary soft-pack Li-ion battery is taken as the study object.First,the constant current charging experiment is carried out,and the thermal performance of the battery during the charging process is tested.Then,by measuring the actual dimensions of the internal components of the ternary Li-ion battery,the three-dimensional electrochemical model at the mesoscopic scale and the three-dimensional thermal model at the macroscale are established with the help of COMSOL Multiphysics software,and the coupling relationship between the two is constructed.The electrochemical performance and thermal performance of the battery during constant current charging are obtained by simulation calculation,and the results are compared with the experimental results to verify the effectiveness of the modelFinally,based on the established electrochemical-thermal coupling multi-scale finite element model of the ternary Li-ion battery,the different fast charging methods such as constant current,constant voltage,constant current-constant voltage,stage constant current and pulse charging are analyzed.The effect of these method on the thermal performance of the battery provides a reference for the selection of the fast charging method and the design of the thermal management system for fast charging applications. |
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