Abstract: In order to solve layer design problems of lightweight carbon fiber composite battery box, a battery box of PEV is taken as the research object by using carbon fiber composite material T300/5224. Under the conditions of vertical bumpy, sudden braking and sharp turning, OptiStruct was used to optimize the plies distribution through free size optimization, size optimization and shuffle optimization. The symmetrical arrangement was used to reduce the influences of coupling stiffness, and the manufactured thickness of each ply was 0.125 mm. The best plies order is found to the [±45/0/±45/0/90/0/90/0/±45/0/90/0/90/0/±45/90/±45/90/±45/90/±45/90]_s. Under the premise of meeting the performance demands, component strength check is performed so that the stiffness of battery box is improved and its weight is greatly reduced. Compared with the same steel battery box, the weight is reduced by 65.89%, the advantages of high specific strength and large specific modulus of the carbon fiber composite material are fully exerted, and the effect of lightweight is obvious.

Key words: carbon fiber composite material, free size optimization, size optimization, shuffle optimization, li-ghtweight