Understanding batteries integration in EV structure: Trade-offs and optimization

Integrating lithium-ion battery packs into the electric vehicle (EV) structure can lead to enhancing structural performance and efficiency. Although EV manufacturers are conducting internal research there are limited published studies on the trade-offs of using batteries as structural components. This study addresses the research gap by examining how battery integration affects the stiffness, Noise, Vibration, and Harshness (NVH), and dynamic overall performance of electric vehicles using a two-phase approach. A simplified NVH beam model was derived from an Original Equipment Manufacturer (OEM) electric crossover vehicle Body-In-Prime (BIP) NVH model to serve as a base model. In Phase 1, integrating the battery with H-beam reinforcements shown to increase the bending and torsion mode frequencies by a maximum of 54 % and 12 %, respectively. In Phase 2, direct battery integration with a complete modification of the battery pack assembly shown to further enhance these improvements by 102 % for bending and 36.6 % for torsion mode. Size optimization was then employed to make the structure lighter while maintaining the Phase 1 and 2 bending mode frequencies at 39.96 % and 62.45 %, and the torsion mode frequencies at 12.64 % and 30.14 % higher than the base model. Through size optimization, a maximum weight saving of 75 kg was achieved compared to the base model, and 87 kg was saved in comparison to the integration model across both phases. These results demonstrate that battery integration can significantly enhance stiffness and enable considerable weight savings for future EV designs.