A Carbon Fiber Polymer Composite Car Fender as a Battery

Many auto manufacturers use carbon fiber composites to save weight. Less weight means less power is required to move the vehicle. The Boeing Corporation uses 50 percent composite construction to save weight in the 787 Dreamliner which makes it the most fuel efficient plane they build. I use carbon fiber composites to build lightweight but very strong boats and carbon fiber headlights for night-time marathon paddling. My cell phone has a mil-spec waterproof carbon fiber body. Now imagine these carbon fiber composite products as electrical energy storage to power the same device. The first thing that comes to mind is a really weird battery. I did some research and found a 2010 news release by Imperial College in London. Here's what I learned about polymer composite electrical energy storage.

The Imperial College developed and patented a prototype concept using carbon fiber and specially formulated polymer as an electric storage device. A $4.6 million project was formed with partners which include the Volvo Automobile Company to research and develop applications for this energy storage concept. Volvo is investigating the feasibility of replacing metal spare tire wheel well components in the trunk with lightweight polymer. They estimate a 15 percent reduction in vehicle weight is possible. The electrical storage potential of the composite would be added to standard vehicle battery capacity. Prototype electrical storage capacity would be minimal but there is no reason why far more body parts or structural components can't be added if the concept proves out. Consider an electrical storage battery the size of a car roof. Carbon composites are used in boats, cars, airplanes and many other products so the mechanical fabrication process is well known. Shape and size are probably not a problem.

Pictures of prototype samples appear to be a sandwich of common carbon fiber cloth separated by a layer of fiberglass saturated in a special polymer. The polymer I use when building boats is epoxy. I doubt the energy storage polymer is so simple. The finished product must have the right combination of collector plates and dialectric film between the two. A simple capacitor can be made with layers of aluminum foil and plastic film. The charge is stored electrostatically rather than as a chemical reaction. This makes the polymer energy device more like a capacitor, or ultracapacitor, than a battery.

Batteries give up low volts over long periods while ultracapacitors give up high volts over short periods. Batteries recharge slowly while capacitors charge very quickly. This makes ultracapacitors a good choice where power demands are high but short such as in electric vehicle acceleration, climbing hills and for quick charges from regenerative power when braking. The capacitors would complement rather than replace standard vehicle batteries. Where power demands are low, such as a cell phone, the energy storage polymer may entirely replace the battery. Think how small a cell phone might be with no large battery. Capacitors can be recharged thousands more times than batteries.

The information about carbon fiber polymer composite energy storage is fairly sparse. I found just enough to pique my curiosity. Carbon powders, nanotubes and flexible polymer panels are also being investigated. Dr. Emile Greenhalgh, one of the inventors at Imperial College, cautions that it might take a decade before the new material is ready to replace a conventional battery. But the possibilities are high and the potential exists.