Electric cars: put a battery in your roof  

AFP has an article on some nanotechnology research in the UK which may lead to lighter batteries - Electric cars: put a battery in your roof.

A nanoscale material developed in Britain could one day yield wafer-thin cellphones and light-weight, long-range electric cars powered by the roof, boot and doors, researchers have reported.

For now, the new technology -- a patented mix of carbon fibre and polymer resin that can charge and release electricity just like a regular battery -- has not gone beyond a successful laboratory experiment.

But if scaled-up, it could hold several advantages over existing energy sources for hybrid and electric cars, according to the scientists at Imperial College London who developed it.

Lithium-ion batteries used in the current generation of plug-in vehicles are not only heavy, which adds to energy consumption, but also depend on dwindling supplies of the metal lithium, whose prices have risen steadily.

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

Another plus: conventional batteries need chemical reactions to generate juice, a process which causes them to degrade over time and gradually lose the capacity to hold a charge.

The carbon-polymer composite does not depend on chemistry, which not only means a longer life but a quicker charge as well.

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

As hard a steel, it could in theory double as the body of the vehicle, cutting the weight by up to a third.

The Tesla Roadster, a luxury electric car made in the United States, for example, weighs about 1,200 kilos (2,650 pounds), more than a third of which is accounted for by batteries, which turn the scales at a hefty 450 kilos (990 pounds). The vehicle has a range of about 300 kilometers (185 miles) before a recharge is needed.

"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."