February 15, 2010

New Material To Change Efficiency Of Electric Cars

Parts of a car's bodywork could one day double as its battery, according to the scientists behind a new project announced recently.

This technology is a patented mix of carbon fiber and polymer resin that can charge and release electricity just like a regular battery.

According to the developers at Imperial College London, if scaled-up, this material could hold multiple advantages over existing energy sources for hybrid and electric cars.

Currently the lithium-on batteries used in plug-in vehicles are not only heavy, but depend on dwindling supplies of the metal lithium, which has a rising price.

The new material is entirely synthetic, which means production would not be limited by availability of natural resources.

Also, conventional batteries need chemical reactions to generate juice, a process that causes them to degrade over time and lose the capacity to hold a charge.  The carbon-polymer composite is not dependent on chemistry, which will give it a longer life and would help it charge quicker.

Emile Greenhalgh, an engineer at Imperial College and one of the inventors, explained that because the material is composed of elements measured in billionths of meter, "you don't compromise the mechanical properties of the fibers."

The material, which is as hard as steel, could also double as the body of the vehicle, which would cut down the weight by up to a third.

The Tesla Roadster, a luxury electric car in the U.S., weighs about 2,650 pounds, which 990 pounds of is due to the weight of the batteries.  The vehicle can go 185 miles before it needs to be recharged.

"With our material, we would ultimately lose that 450 kilos (990 pounds)," Greenhalgh said in an interview. "That car would be faster and travel further."

Vehicles with bodies made from this new material would also shed weight because it is four times lighter than steel, but just as strong and stiff.

"It is the sort of thing you find in tennis rackets or fishing rods -- a carbon fiber composite," Greenhalgh said.

"We aim to increase the surface area of the fibers as much as possible without degrading the mechanical properties. The larger the surface, the more electrical charge they can store."

Last week, the European Union announced it would push in $4.6 million over the next three years into helping develop the technology.  Imperial College will coordinate a project spread over nine companies and institutes in Britain, Sweden, Germany and Greece.

Volvo has said it might build a demonstration panel into an existing electric car prototype.

The researchers expect that within three years they will shave off 15 percent of the weight of the car.  Within five to six years they expected to have integrated the material into the body.

Greenhalgh said that it would take a decade before the new material could fully replace existing batteries.

One thing that is questioned is the cost of the material.

He said that carbon fiber is more expensive than steel, but mass production would help bring down costs dramatically.


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