Wood-steel hybrid beams for electric vehicle battery housings: a comparative study with aluminum profiles in bending load case

The automotive industry faces mounting pressure to reduce its environmental footprint, particularly in the electric vehicle (EV) era. While EVs mitigate tailpipe emissions, the production of energy-intensive components like aluminum remains a sustainability challenge. Battery housings, critical to structural integrity and crash safety, traditionally rely on extruded aluminum profiles for their outer frames. This study proposes a sustainable alternative: wood-steel hybrid profiles for EV battery housing applications. Quasi-static three-point bending tests were performed on hybrid beams with distinct wood cores (birch, poplar, and paulownia) encased in rectangular profiles made from high-strength complex-phase steel sheets. Performance metrics—including maximum force, bending stiffness, and specific energy absorption—were evaluated and compared to numerical simulations of mass-equivalent three-chambered aluminum beams (ductile EN AW 6061-O and high-strength EN AW 6061-T6), which serve as simplified analogues of real-world extrusion profiles. Results demonstrate that wood-steel hybrid beams outperform ductile aluminum counterparts, with poplar- and birch-core hybrids achieving 88% higher peak forces and 98% greater energy absorption. Paulownia-steel hybrids exhibited moderate improvements, delivering 60% higher peak forces and 34% greater energy absorption. Compared to high-strength EN AW 6061-T6, hybrids matched peak forces and energy absorption at low intrusion levels but provided 76% higher energy absorption under large deformations. This research highlights the potential of wood-steel hybrids to enhance crash safety while significantly reducing the carbon footprint of vehicle structures. By leveraging renewable materials and surpassing the performance of conventional alternatives, these hybrid beams offer a compelling solution for advancing sustainable automotive design, particularly in key components such as EV battery housings.