电动汽车车架及电池箱轻量化设计研究

Research on Lightweight Design of Electric Vehicle Frame and Battery Box

随着环保意识的提升,人们越来越追求绿色低碳出行,新能源汽车已成为未来交通发展的主要方向。目前纯电动汽车常用的电池,均存在比能量和比功率偏小的问题,制约了电动汽车加速性能的提高和续航里程的增加,轻量化设计对于节能减排和提高电动汽车的动力性能具有重要的意义。本文主要研究通过结构优化对电动汽车车架及电池箱进行轻量化设计,首先在SolidWorks中对某型纯电动乘用车的车架和电池箱进行建模,并利用simulation做了静应力分析,确定优化设计的空间,通过分析结构特点确定车架采用拓扑优化,电池箱采用尺寸优化的方法进行轻量化设计。车架在拓扑优化的过程中,从相对质量密度的等值图解中看到可以移除的材料多在梁的中部,因此在优化设计时采用中空的型材,壁厚5mm,同时车架前后的横板用横梁代替,并增加了圆角过渡,减少应力集中。优化后的车架通过静应力分析验证了其强度和刚度,优化后车架的质量为154Kg,减重76.6%。电池箱主要对电池定位壳、内箱体和外箱体进行壁厚优化,取不同典型工况下得到的符合许用应力范围的最小壁厚中的最大值,最后确定优化后的电池定位壳壳厚T定=1mm,优化后质量为1.75 Kg,减重74.89%;内箱体侧板厚T内=4mm,优化后质量为30.85 Kg,减重40.28%;外箱体侧板厚T外=4mm,优化后质量为19.59 Kg,减重46.2%。研究可为同类电动车的轻量化设计提供参考。

With the improvement of environmental awareness,people are increasingly pursuing green and low-carbon travel,and new energy vehicles have become the main direction of future transportation development.At present,the battery commonly used in pure electric vehicles has the problem of small specific energy and specific power,which restricts the improvement of the acceleration performance of electric vehicles and the increase of the driving range.Lightweight design is of great significance for energy saving and emission reduction and improving the power performance of electric vehicles.This paper mainly studies the lightweight design of the frame and battery box of an electric vehicle through structural optimization.First,the frame and battery box of a pure electric passenger car are modeled in SolidWorks,and the static stress analysis is carried out through simulation to determine the space for optimization design.Through the analysis of structural characteristics,it is determined that the frame adopts topology optimization and the battery box adopts dimension optimization to carry out lightweight design.In the process of topological optimization of the frame,it can be seen from the equivalent diagram of the relative mass density that the material that can be removed is mostly in the middle of the beam.Therefore,hollow profiles are used in the optimization design,and the wall thickness is 5mm.At the same time,the transverse plates before and after the frame are replaced by beams,and the rounded corner transition is increased to reduce stress concentration.The strength and stiffness of the optimized frame were verified by static stress analysis.The weight of the optimized frame is 154Kg,and the weight is reduced by 76.6%.The battery box mainly optimizes the wall thickness of the battery positioning shell,the inner box and the outer box,and takes the maximum of the minimum wall thickness that is in line with the allowable stress range under different typical working conditions.Finally,the shell thickness of the optimized battery positioning shell is determined to be 1mm,the optimized mass is 1.75 Kg,and the weight is reduced by 74.89%.The thickness of the side plate of the inner box is determined to be 4mm,the optimized mass is 30.85Kg,and the weight is reduced by 40.28%;The thickness of the side plate of the outer box is determined to be 4mm,the optimized mass is 19.59Kg,and the weight is reduced by 46.2%.The research can provide reference for the lightweight design of similar electric vehicles.