EU researchers make flexible solar battery

4 Apr, 2007

European Union-funded project designs thin battery cells which recharge when exposed to light.

Forget plugging in your electronic gadgets - just leave them out in the sun. A new European Union (EU) funded research project has designed a flexible polymer battery which recharges when exposed to light.

According to a statement from the EU, the battery has thin-solar cells which are held inside a flexible gas barrier to prevent them from degrading when exposed to air. At just two grams in weight and just one millimetre thick, the flexible battery is small enough to be used in low-wattage gadgets - including flat smart cards and mobile phones.

Each solar strip can produce 0.6 volts, and the batteries can be scaled up simply by adding more strips to a cell, the statement said.

"It's the first time that a device combining energy creation and storage shows [such] tremendous properties," Gilles Dennler, a coauthor of the paper and a researcher at solar startup Konarka Technologies, told the Massachusetts Institute of Technology's (MIT) Technology Review journal. "The potential for this type of product is large, given [that] there is a growing demand for portable self-rechargeable power supplies."

While low-light, such as sunlight shining through a window, was enough to charge the battery, artificial light was too weak - suggesting such batteries for mobile phones may be a while off yet. But as the solar cells are small and can be produced cheaply, they could be ideal for toys, RFID tags and sensors, said the Technology Review.

The project consortium said a solar-battery device could hit shops by next year. The research was published in Solar Energy journal.

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