PORTLAND, Ore. — As researchers rush to commercialize printable batteries that pattern organic semiconductors onto paper-thin, flexible substrates, a German team claims to be on-track for a 2010 product launch.

Scientists at the Fraunhofer Research Institution for Electronic Nano Systems together with colleagues from Chemnitz University of Technology and Menippos GmbH (all based in Chemnitz, Germany) collaborated on product development. They are targeting applications such as smart credit cards with battery-powered displays to show balances and other account information.

Fraunhofer's batteries use zinc anodes and manganese cathodes, which react with one another to produce electricity. The materials slowly dissipate over the lifetime of the battery, making them suitable for short-term applications like greeting cards with built-in music players, The researchers are aiming at a price point under 10 cents per card.

Fraunhofer Research's small, thin battery can be mass-produced using conventional printers, then applied to flexible substrates.

The batteries are printed using a silk screen printing process in which a rubber lip presses the organic semiconductor materials through a screen onto a flexible substrate. The lithographic-like technique uses templates to pattern layer upon layer--each about the width of a human hair--of battery components until enough bulk has been achieved for a particular application.

Printable batteries for smart cards would weight less than 1 gram and measure less that 1-mm thick. The organic materials produced 1.5 volts per cell, like conventional batteries, but use no harzardous chemicals like the heavy metals in conventional rechargeable and alkaline batteries.

Fraunhofer researchers said their battery is working in their lab, and its partners estimate that the first commercial designs will be ready for beta testing later this year.