Lightweight Design Of Battery-pack Enclosure Based On Orthogonal Experimental Design And Second-order Response Surface Methodology

In recent years,to cope with climate change and promote green development,many countries have strengthened their plans for new energy vehicles.Some positive measures were introduced to encourage the development of new energy vehicles.Electric vehicles,as a typical representative of new energy vehicles,have advantages such as zero emission and high efficiency.They have gradually become the focus of automobile companies.The battery-pack system,which is one of the core components of electric vehicles,directly affects the cruising range and driving safety of electric vehicles.In order to improve the cruising range and energy density of electric vehicles,lightweight design and optimization of the battery-pack enclosure is of great significance.This study takes a certain battery-pack system as an example to perform the lightweight design.The main research work is described as follows:1)The detailed structure of the battery-pack enclosure is investigated.The connection between the components is modeled according to the actual welding relationship.Then the finite element model of the battery-pack enclosure is established.The constrained modal analysis of the battery-pack enclosure is performed.And the numerical results are compared with the bench test results,which shows that the finite element model of the battery-pack enclosure is accurate and can be used for further analysis.2)The random vibration analysis of the battery-pack enclosure is performed to obtain the stress value of each components.In such a way,nine components with larger stress and heavier weight are selected for optimization.The thickness and material of these components are defined as design variables.The selected materials include 590 DP,780DP,and 980 DP.108 sets of experimental designs are obtained based on the orthogonal experimental design method.And stress response values from the random vibration analysis of each component are achieved through numerical analysis,which provide basic data for subsequent establishment of second-order response surface model.3)A second-order response surface model based on random vibration is built,and the approximated model is analyzed whether it can be used for the design optimization.The multi-island genetic algorithm is adopted for lightweight design,in which minimizing the weight of the battery-pack enclosure is the design objective,and the stress requirements of each component is the constraint.The results show that the weight of the optimized battery-pack enclosure decreases from 61.23 kg to 54.05 kg,a 11.73%lightweight gain is achieved.4)The fixed frequency vibration analysis,mechanical shock analysis,crash and crush analysis are performed for the optimized model according to the standard,for the purpose of model verification.The result shows that the optimized battery-pack enclosure can meet the requirements under various conditions.Further,the prototype of the batterypack enclosure is manufactured for the continuous verification and validation.