Face it, electric cars are heavy, and that weight is a factor in what many perceive as the cars main problems: limited range, lack of acceleration and insufficient power for anything other than urban commuting.
The heaviest single component in an electric vehicle is the battery. The Nissan Leaf, for example, has a curb weight of nearly 3,500 pounds. The battery module alone weighs close to 700 pounds. That’s 20 percent of the total vehicle weight. If some pounds could be shed from chubby battery modules, EVs would be much more efficient.
Now, engineers from the Fraunhofer Institute for Chemical Technology ICT in Pfinztal, Germany, are developing a mass-production-ready, crash-safe battery housing that reduces weight and meets strict safety requirements. In their tests, the battery housing that surrounds a battery that weighs 750 pounds only weighs 77 pounds. “Traditional solutions made of steel weigh up to 25 percent more,” project manager Manfred Reif. “The battery housing can withstand a crash, assuming a ten-fold gravitational acceleration.” And even if a sharp object collides with the housing at 45 mph, the highly sensitive battery on the inside remains intact. In addition, the 16 lithium-ion modules are protected from humidity, and a semi-permeable membrane to equalize pressure also guarantees that the batteries are able to “breathe.”
In current battery housing designs, steel components are welded together to make these boxes. What make the new battery protection so special are the new fiber-reinforced composite materials and directionally oriented fiberglass structures or custom-made metal inserts. Fiber composites have been used for a long time in the manufacturing of airplanes, but to scale for the numbers used in auto production, the team has had to design new processes.