Safety Comparison of Geometric Configurations of Electric Vehicle Battery under Side Pole Impact 2022-01-0265

Batteries have various sizes and can be configured into different layouts in battery pack on electric vehicles. Crash safety performance is one of the key requirements in choosing battery geometric characteristics and designing layout of battery cells in battery pack. In this study, we compared impact responses of different configurations and geometric characteristics of battery cells under side pole impact. The side pole impact is a relatively dangerous collision type for electric vehicles, often causing large deformation and damage to the battery. Using a production battery pack, we first conducted side pole impact tests with sled tester, and then simulated the test configuration. Using the test simulation as baseline model and keeping the total volume and mass of battery cells unchanged, we expanded the simulation matrix to several different layouts of battery cells, including battery’s length direction parallel/vertical to the vehicle length direction, thin/thick battery, long/short battery, and so on. Deformation and energy dissipation of battery cells were used to gage the material damage, which is related to the risk of occurrence of internal short circuit. The results have shown that, battery layout has significant influence on collision safety against side pole impact. Between different layouts, the energy dissipation by jellyrolls varies from 59% to 191%, comparing to that of the baseline model. The transverse layout has multiple battery cells to withstand side pole impact, resulting in relatively low energy dissipation of jellyrolls. Thin battery cells are individually weak but collectively strong in battery pack, and thus helpful to disperse the impact energy to the far-field, resulting in relatively small deformation of battery cells near impact zone.