Although it might seem like a recipe for disaster, recent scientific research indicates that placing flammable EV batteries in a wooden box is not only feasible but also potentially safer and more environmentally friendly than existing practices. Concerns about battery fires, which are frequently caused by damaged lithium-ion cells, are growing along with the popularity of electric vehicles (EVs). Historically, automakers have housed these batteries in bulky, energy-intensive aluminium. However, a group from the Technical University of Graz in Austria has presented wood, an unexpected substitute.
The scientists contrasted hybrid battery housings composed of layers of steel and sustainable woods like birch, poplar, and paulownia with conventional aluminium battery housings, such as those found in a Tesla Model S. Since wood is renewable and has a lower carbon footprint than steel, these wood-steel hybrids greatly lessen their negative effects on the environment.
It was during crash testing that the real surprise occurred. The Bio!Lib wooden housings did exceptionally well in critical pile crash scenarios, where cars struck a steel obstacle at high speeds. Up to 98% more energy was absorbed by the poplar and birch varieties than by ductile aluminium, and 76% more than by high-strength aluminium. This is because wood has a naturally porous structure that efficiently dissipates crash energy. The wooden housings also exhibited remarkable resistance to bending and deformation.
The researchers used cork in the design to address fire safety. When exposed to excessive heat, cork, another naturally occurring and renewable material, turns carbonised. Lead researcher Florian Feist claims that this charring protects the internal structure from high temperatures by drastically lowering thermal conductivity. In comparison to the aluminium Tesla battery housing, the wood-based housings maintained a “cold side” temperature that was up to 100 degrees Celsius lower during fire testing.
This research offers a creative substitute for the specialised blankets that firefighters are increasingly using to put out EV battery fires that are difficult to put out. In addition to having a lower carbon footprint, a wood-based, cork-enhanced battery case promises better crash performance and fire resistance. Although it may seem absurd at first, science is firmly arguing that wood may be the material of the future for safer, more environmentally friendly EV battery design.
