Abstract: The lightweight design of the battery box of an electric vehicle is conducted. Since the uppercase is mainly for sealing, structural optimization is taken as its lightweighting scheme; while the lowercase acts as a load-bearing component, thus its lightweighting scheme is using carbon fiber to replace original material. In the lightweight design of lowercase, multi-objective optimization algorithm is introduced. The results of simulation show that the lightweighting schemes adopted not only reduce the mass of battery box, but also effectively increase its stiffness and modal frequency

Key words: electric vehicle, battery box, lightweight design, carbon fiber composite, multi-objective optimization