Novel Tube-in-Tube Steel Side Sill Reinforcement Design and Validation for Enhanced Crash Performance in EVs

Increased use of Electrical vehicles (EVs) brings in unique structural design challenges particularly in Side Impact scenarios when the battery pack positioned near the sill region elevates the possibility of battery penetration and thermal runway in crash event. Thus, Electric Vehicles require unique structural design solutions. This study focuses on a novel steel tube-in-tube Side Sill reinforcement design and its performance benefits over a traditional aluminum Side Sill reinforcement commonly used for battery protection in EV vehicles body components. The proposed Steel Side Sill design layout mainly focuses on structural rigidity and improved load transfer during side pole impact crash cases and addressing manufacturing complexity and cost reduction opportunity. Multiple Steel Side Sill reinforcement design iterations are carried out by finite element analysis with software like LSDYNA Hyper works [1]. The goal was to develop an optimal tubular design - maximizing load transfer and energy absorption. The study was mainly divided into two stages, 1) CAE Full Vehicle and Component; 2) Component Test Validation. Initial design parameters were derived based on full vehicle and component CAE and then the design was validated using physical testing. The results show that the tube- in-tube Side Sill reinforcement structure has similar performance compared to base Aluminum design and indicated possibility of reduced manufacturing complexity, cost and mass saving options. These findings proved that the proposed novel Side Sill reinforcement in EV specific body in white (BIW) is helpful to design safer vehicles and effectively meet both regulatory and consumer matrix.