Crash-Resistant Battery Housing for Electric Cars
- Thursday, 06 October 2011
Fraunhofer scientists working on electronic drives have replaced a battery box for lithium-ion batteries with a lightweight component. Not only does the housing save weight and sustain no damage in an accident – for the first time ever, it can also be mass-produced.
Electric cars should weigh as little as possible because when stopping and going, every additional pound/kilogram must be accelerated with considerable energy expenditure. And the lighter the electric vehicle, the longer it can be on the road without having to be plugged back into a power outlet. Engineers from the Fraunhofer Institute for Chemical Technology ICT in Pfinztal, Germany, are developing manufacturing concepts that have one goal – they want to gradually replace individual components in the vehicle with lightweight ones.
"However, this cannot affect the stability or the safety of the passenger," said Manfred Reif, project manager in the joint project "Fraunhofer System Research for Electromobility."
The fact that this is possible is proven by the researchers with the Artega GT, a sports car that was modified into a prototype with an electric drive, where the electric motor is located in the rear. The experts, along with colleagues from other Fraunhofer Institutes, have developed a mass-production-ready, crash-safe battery housing that meets strict requirements.
The battery housing that surrounds the battery - which weighs weighs 340 kilograms (749.57 lb..) - only weighs 35 kilograms (77.16 lbs.). "Traditional solutions made of steel weigh up to 25 percent more," said Reif. "The battery housing can withstand a crash, assuming a ten-fold gravitational acceleration." If a sharp object collides with the housing at 60 km/h (45mph), the battery on the inside remains intact. 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."
The new battery protection also includes new fiber-reinforced composite materials. The scientists have developed a special process chain with cycle times that make the production of high unit counts possible. “The process chain is designed so that many steps can be run simultaneously,“ said Reif. For example, the plastic is heated up parallel to the production step, and elements are prepared that ensure load and tensile strength or the attachment to the storage in the rear of the Artega. This includes, for example, directionally oriented fiberglass structures or custom-made metal inserts. All the individual components are then assembled and pressed together in a "one-shot process."