基于多学科优化的锂离子动力电池包轻量化设计

Lightweight design of lithium-ion power battery pack based on multi-disciplinary optimization

为实现电动车锂离子动力电池包的轻量化、结构耐久性设计,依据国标要求,建立有限元模型,并进行噪声振动粗糙度(NVH)、结构耐久性和碰撞安全工况的分析。将频域随机振动载荷等效成时域随机信号,进行焊点疲劳分析。搭建多学科自动化样本计算流程,生成多学科近似模型,并进行优化分析。疲劳寿命预测结果与实验结果一致。结果表明:采用该多学科优化设计方案,质量减少4.0kg,减少率6.5%;模态降低了13.4%;最大焊点损伤值0.52,满足目标要求,在实验中未出现破坏。因此,该多学科优化设计可以快速准确地找到全局最优解。

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.