Impact Cumulative Damage Research For Power Battery Pack

Our country has strict testing standards for electric vehicle power battery pack, including safety testing of mechanical impact test requirements that Pack to withstand vertical 25g,15ms half sine impact 3 times. Due to high cost and long cycle of Pack test, relying on test methods to test Pack structure would meet the safety requirements which are bound to restrict the product development. Therefore, the numerical simulation research about damage and the accumulative mechanism of Pack structure under the condition of impact, for improving the quality of the design of the Pack, saving development costs, shortening product development cycle, is very necessary.This paper adopts the method of numerical simulation combined with experiment to study the damage and accumulation regularity of Pack structure under repeated impacts. First of all, with Ls-Dyna software as the platform, cumulative damage numerical simulation method of repeated impacts is put forward:Calculating the response of structure under impact loading with explicit algorithm; Getting the deformation, residual stress and plastic strain of structure after unloading load by dynamic relaxation method; Implementing damage parameters will be transmitted by completely restarting method; Assessing degree of structural damage was made by Johnson-Cook failure model. Secondly, a simple experimental model is designed and made numerical simulation, getting the experimental model of distribution and accumulation regularity of damage, and verifying that the cumulative damage the accuracy of the numerical simulation method by comparing the experimental and numerical simulation result. Finally, using the cumulative damage numerical simulation method to calculate the distribution and accumulative regularity of Pack structural damage under three impacts, which provide important reference for structure improvement.The numerical simulation results of experimental model and Pack show that:Under same impact loading, the first impact caused the most damage on structure, the damage of the subsequent impact is relatively small.Structural damage has a logarithmic function type. Structural damage of few times impacts cumulative speed faster, with the impact number increase damage cumulative speed slow.