Tech - Bendy battery gives smart fabrics a charge

A FLEXIBLE battery that can be woven unobtrusively into fabrics could one day provide electricity for gadgets buried in your clothing.

While flat, flexible batteries have been connected to T-shirts sporting arrays of flashing LEDs, they have not been built into the very stuff of a garment. Maksim Skorobogatiy and colleagues at the Polytechnic School of Montreal in Canada say they have done just that.

To build their battery they sandwich a solid polyethylene oxide electrolyte between a lithium iron phosphate cathode and lithium titanate anode. All of these are thermoplastic materials, which can be stretched under mild heating (Journal of the Electrochemical Society, DOI: 10.1149/2.020204jes).

The material looks like artificial leather. After stretching, the team wove strips of it into cotton fabrics and used conductive threads to connect these batteries in series. This configuration was used to illuminate LEDs. "It's the first fully wearable, soft lithium-ion battery that uses no liquid electrolytes," claims Skorobogatiy.

A garment made of the material could provide hundreds of volts, he says, enabling applications in which a battery-backed garment could deliver power in an emergency. "We have enough power to emit a powerful distress signal or even save a life by defibrillating a patient," he says. The team now faces a more mundane challenge: waterproofing the technology and making it washable.

Sandy Black, who researches smart textiles at the London College of Fashion, thinks bags, backpacks and medical-monitoring garments could be first to use such technology. "I think this whole area is reaching critical mass. Something mainstream cannot be too far away."

http://www.newscientist.com/