Design of the BIW structure for battery pack protection in case of side pole impact.

Electric vehicles (EVs) are becoming more popular than Internal Combustion Engine (ICE) powered vehicles, but their battery and motor components elevate their Gross Vehicle Weight (GVW), posing unique collision risks. Manufacturers strategically mount the high voltage (HV) battery packs under the passenger compartment to lower the Centre of Gravity and shield them from the front impacts. However, side impacts remain a concern, as the battery deformation in such instances could trigger fires or explosions, endangering occupants. To address this, crashworthiness designs adhere to New Car Assessment Program (NCAP) standards, particularly against side pole impact and side mobile barrier impact. Unlike the frontal section of BIW, which typically has larger crush space to absorb the crash energy, extensive design attention is required to the vehicle's side structure to absorb pole impacts without transmitting excessive force to the battery pack. Utilizing aluminium extrusions and sheet metals, the vehicle's side sill structure is engineered with geometries that efficiently absorb impacts while protecting the HV battery and occupants as well. The key parameters assessed for battery protection include, 1. Cell force, 2. Acceleration of the battery pack, 3. Strain in the battery cover plate, and 4. Force distribution between the BIW structure and the battery pack.