Next stop for solar cell technology: your clothing, perhaps

By Carsten Hoefer Sep 12, 2011, 17:00 GMT

Munich - Every mobile worker knows the nightmare: The rechargeable battery in the mobile phone or laptop computer is dead, contact with the outside world is severed, customers are angry and the boss is throwing a fit.

In a few years, such crises could become a thing of the past as technology burrows deeper into the apparel industry. Scientists and clothing makers are experimenting with solar cells built into coats, jackets and backpacks that can provide power for portable electronic devices.

Traditional silicon-based cells are inflexible and therefore unsuited to textiles. But help may be on the way from flexible, organic solar cells printed on polymer foils, a new development in which the Fraunhofer Institute for Solar Energy Systems (ISE), based in Freiburg, Germany, has been instrumental. The venerable Munich clothing maker Lodenfrey is interested.

'I think it's exciting,' said Klaus Faust, head of Lodenfrey's menswear department. 'You're taking a walk in the sunshine and recharging your mobile phone.'

Solar cell jackets will not be ready for the market until a number of technical obstacles have been overcome, however. One is the ability to withstand laundering. So far, solar cells are unable to withstand a complete machine wash cycle at 60 degrees centigrade.

ISE scientists actually had another clientele in mind for their organic solar cells: the building industry.

'It's a relatively young technology that, in the long term, can make a contribution to the energy supply,' according to ISE spokeswoman Karin Schneider, who said that organic solar foils might someday be glued to awnings and the walls of buildings for the purposes of electricity generation.

The apparel industry is interested, too. 'We're still a little bit away from large-scale production, but a lot is in flux,' Schneider said.

Jackets or sweaters with embedded photovoltaic cells could have various uses. 'It's conceivable, for example, to have safety vests with built-in illumination,' Faust said. 'A possible disco gag would be a jacket that glows to the beat of the music.'

Lodenfrey is tinkering with other innovations as well. In collaboration with an Israeli inventor, it is working on a motorcycle jacket with built-in air conditioning. A further possibility: jackets and coats made of fabric that heats up.

'A light jacket with collar heating for the convertible, for instance,' Faust suggested, adding that an attractive option for commuters using public transport would be a winter coat that heats up.

While Lodenfrey is known for its traditional Bavarian garb, it keeps an eye out for innovation. 'Living from tradition alone is fine, but it's a little risky,' Faust remarked.

He said that networking with scientists and other companies was of central importance. Since a clothing manufacturer is not a high-tech concern, he noted, 'you can only achieve great new innovations in clothing when you find partners.'

This is where politics comes in. Germany's federal and state governments support innovation in two ways. First, they provide subsidies for research projects, and, second, they have programmes that bring scientists together with small and medium-sized businesses.

The German federal government is subsidizing development of organic solar cells. And Lodenfrey is taking advantage of an 'innovation voucher' offered by the Bavarian Economics Ministry for its work on heating fabrics. Under the voucher programme, the ministry is matching the company's expenditure of 7,500 euros (10,570 dollars).

'It doesn't always have to be big things,' Faust said of the matching grant. 'Small ones help, too.'

The Bavarian Economics Ministry is satisfied, too. It has approved 716 innovation vouchers since 2009, many of them for projects whose fruition seems a long way off.

'In our view, it's a complete success,' a ministry spokesman said. Meanwhile, it will likely take a few more years before solar-powered textiles are ready for the market.