Design Study of Battery System Protection Structure Based on Hybrid Material Fiber Metal Laminate (FML)

摘要

With the grcopyowing size of the electric vehicle (EV) market, the study of the battery system is paramount. Lithium-ion batteries have a high risk of flammability in the event of an accident or a collision that causes a short circuit. One of the highest potential threats to EVs is ground impact from stones or projectiles impingement that can hit and penetrate the battery pack. Therefore, it is necessary to develop a lightweight structure that can protect batteries in the event of dynamic impact load. The material used for the protection structure is fiber metal laminate (FML), which is a hybrid material consists of thin metal layers bonded together by intermediate composite. Evaluation of the risk of battery fire due to short circuit (battery shortening) and energy absorption of the protection structure is done by using the nonlinear finite element method. Parametric studies were conducted to investigate the effect of thickness, bonding strength, as well as two damage parameters such as failure and softening effect. Simulation results show that increasing the softening parameter can increase energy absorption but also increase the battery shortening. While increasing all the other parameters can increase energy absorption and reduce battery shortening. In this study, the most effective design for the protection structure was obtained, which is 1 mm-thick aluminum as the top and bottom layer, and 4.8 mm-thick carbon fiber reinforced polymer (CFRP) as the intermediate layer.