基于应变响应的锂离子电池多物理场耦合模型构建OA

During charge-discharge cycling,batteries generate heat and stress,which will easily cause casing deformation,and in severe cases,result in the hazards like leakage,fire,or explosion.To investigate the deformation behavior of battery casings,a strain-response-based electrochemical-thermal-mechanical multiphysics coupling model was established,and the strain distribution and influencing factors during discharge were analyzed.The results indicate that the strain of 18650 batteries decreases continuously as the voltage drops during discharge,and the magnitude of strain increases with higher current rates,reaching-115,-158,and-175 με at 0.5C,1C,and 2C,respectively.During discharge process,the displacement in the midsection of the battery casing is larger than that at both ends,the internal temperature is higher than the external temperature,and the axial temperature gradient is smaller than the radial one.The established correlation equation of strain with state of charge(SOC)and temperature has determination coefficients(R2)of 0.99,0.98,and 0.99 at 0.5C,1C,and 2C,respectively,which facilitates calculating strain based on state of charge and temperature.This work provides a theoretical basis for evaluating battery safety from the perspective of casing deformation.