Research On Multi-Objective Optimization Design Method For Lightweight And Crashworthiness Of Automotive Power Battery Pack Structure

As the core power component in electric vehicles,the optimal design of battery pack box structure for lightweighting and crash resistance has gradually become one of the hot spots for research in the automotive industry.However,most of the existing research work is focused on the lightweight design of individual or partial parts of the battery pack box,but there is relatively little research on the multi-objective optimization design of the whole battery pack.Accordingly,this paper establishes a new multi-objective optimization design method for battery pack structure based on an electric vehicle battery pack,using a combination of theoretical research and numerical analysis,from two levels of battery pack components and the whole,to realize the double improvement of battery pack structure lightweight and crashworthiness.The main work and conclusions of this paper are as follows:（1）The finite element performance analysis of the automotive power battery pack structure.The finite element model of the box structure of an automotive battery pack product is constructed,the static performance of the battery pack structure under five typical operating conditions and the dynamic performance of the constrained mode operating conditions are analyzed and verified,and the performance parameter values of the product under each operating condition are extracted.（2）The crashworthiness analysis of the automotive battery pack structure and the optimized design indexes are extracted.The finite element analysis model of rigid crush crash of the battery pack structure is established,and the crashworthiness performance of the battery pack structure is verified by simulation analysis,and the crashworthiness optimization indicators of the battery pack structure are obtained.（3）Based on the contribution degree analysis method,response surface method and NSGA-Ⅱ algorithm,the multi-objective optimization design of the automotive battery pack structure is carried out.The total mass and crush deformation of the optimized components of the battery pack are used as the optimization indexes of light weight and crashworthiness,based on which,the multi-objective optimization design of NSGA-Ⅱ algorithm is carried out,and the optimization results are numerically simulated and verified.The results show that the total mass and crushing deformation of the optimized battery pack components of the optimal compromise solution are 73.71 kg and 62.77mm,respectively,and the corresponding combinations of input parameters are T₁=2.2,T₂=1.9,T₃=2.6,T₄=2.9,T₅=2.8,T₆=2.4,T₇=4.3.Compared with the initial design scheme,the total mass of the optimized component is reduced by 4.31%and the crushing deformation is reduced by 5.97%.