Abstract:

A finite element model (FEM) for a lithium-ion battery pack of an electric vehicles (EV) was established according to the China Standard GB/T 31467.3 “Safety requirements for lithium ion power batteries for electric vehicles” with analyzing noise vibration harshness (NVH), structural durability and crash safety to realize lightweight and structural durability. The weld spot fatigue analysis was carried out with the random vibration load in freguency domain being equivalent to the random signal in time domain. A multi-disciplinary automatic sample calculation-process was built to generate an approximate model with an optimization analysis. The predicting fatigue life was consistent with the experimental results. The results show that by using a multi-disciplinary optimization-design, the battery pack mass reduces by 4.0 kg with a rate of 6.5% with the pack modal-number reducing by 13.4%, while the maximum weld spot damage rate is 0.52, which meets the requirements of the target, and without any failure in the experiments. Therefore, the multi-disciplinary optimization-design can quickly and accurately find the solution of global optimization.

Key words: electric vehicle (EV) ,  light-weight , noise vibration harshness (NVH) , lithium-ion power battery pack ,  weld spot-fatigue ,  multidisciplinary optimization design