Damage Assessment Method of Battery Pack of Electric Vehicle in Undercarriage Collision

Undercarriage impact occurs when vehicle’s ground clearance is incompatible with obstacle on the road. This kind of accidents are particularly dangerous to electric vehicles as battery pack is usually integrated into the vehicle floor. In case of an undercarriage collision, the battery pack could be ploughed through by the obstacle on the road, which could cause damage to battery cells in the pack and occurrence of internal short circuit and thermal runaway. To tackle this new problem, damage assessment method is needed to guide design of protective structure of battery pack. The present paper documents an analysis of battery damages in undercarriage collisions and development of a test method for evaluating undercarriage collisions. We first used a simplified finite element model of battery pack and conducted computer simulations to understand the influences of key parameters. The battery pack model included blade battery cells that had no module-level assemblies. Based on the learning from the finite element analysis, we then developed a generic test method for evaluating undercarriage collisions. The test method is robust in terms of repeatability and the device is adaptable for evaluating a wide range of electric vehicle undercarriage collision. We hope that this test method can become a unified and standard method for evaluating battery pack damage in undercarriage collisions and guide design of protection structures for enhancing safety performance of battery packs.