A numerical investigation of ground impact for hierarchically designed hybrid composite structures in electric vehicle battery cases

The safety of electric vehicle (EV) batteries is essential, particularly in the context of ground impact incidents. This work focuses on the numerical analysis of hierarchically built hybrid composite structures intended for electric vehicle battery casings. Using finite element analysis (FEA), the impact response of newly designed hybrid multifunctional composite materials under impact loading was investigated. After defining composite formulations based on structural and thermal management demands, representative volume elements (RVEs) were created to determine the elastic constants of the composite compositions. Concurrently with the numerical investigations, the composites were manufactured, impact tests were conducted. Response surface methodology and multi-objective optimization identified an optimal formulation, considering elastic modulus, impact strength, and cost. The optimum composite formulation was then subjected to impact simulations using Abaqus CAE software. Three different scenarios were investigated: one with a box-shaped aluminium battery module case, one with a box-shaped composite battery module case, and one with honeycomb features integrated into the box-shaped composite battery module case. Results demonstrated a 26 % reduction in weight through the implementation of a composite-based battery module case utilizing a honeycomb structure. This design maintained mechanical performance comparable to that of a conventional aluminium case.