FEM Study on Enhancing Crashworthiness of Cylindrical Li-Ion Battery Packs Using Spacers Between the Cells

This study proposes a novel approach to improving the crashworthiness of lithium-ion cylindrical cell packs by strategically placing spacers between the cells. The spacers transform the initial line contacts into broader surface contacts, enhancing the overall stiffness of the pack and reducing radial deformation during compression. The concept was evaluated using finite element analysis (FEA), leveraging established material models to efficiently assess the concept’s potential prior to physical testing. To validate the robustness of the homogenized cell material and its application in a full pack, a compression experiment was performed on a pack of nine cells. The experimental results aligned closely with the simulation data, underlining the reliability of the material model and simulation methodology. Across all configurations and load cases—quasi-static compression using a plate or cylinder, and dynamic impact tests simulating crash indentation with a ball—the inclusion of spacers resulted in significant reductions in cell deformation and pack intrusion. The study also examined three spacer materials: aluminum, printed PLA, and printed PLA conditioned at 60 °C. The results showed that stiffer spacers, such as those made of aluminum, were the most effective in improving crash performance. However, even the conditioned PLA spacer, despite its lower stiffness, delivered meaningful benefits by enhancing structural integrity and reducing deformation. This demonstrates the versatility of the spacer concept, which can accommodate a range of materials based on specific performance and manufacturing requirements. These findings establish a solid foundation for the practical implementation of spacers in electric vehicle battery packs. Future research should include experimental validation under real-world crash conditions and explore spacer design and material optimization to maximize crashworthiness without compromising energy density or thermal performance.