Press Release:

Fuel for micro fuel cells Miniature electrolyzer for filling metal hydride storage systems

Micro fuel cells are becoming increasingly interesting as an alternative to conventional accumulators or batteries for powering mobile communication and other interactive devices such as cell phones, laptops, camcorders and PDAs.

But where does the hydrogen for the fuel cells come from? And how can it be stored? Currently, this is achieved in most portable fuel cell applications by using metal hydride storage units, in which the hydrogen is absorbed in metal powder. Fraunhofer ISE in Freiburg has developed a miniature electrolyzing system that enables such metal hydride storage units to be filled with high-purity hydrogen both quickly and decentrally. In just twelve minutes, it generates enough hydrogen from water to power, for example, a camcorder for two hours. A prototype of the mini electrolyzer will be presented at the Hannover Messe trade fair from 24-28 April 2006.

To enable the metal hydride storage units to be filled quickly, Fraunhofer ISE’s hydrogen technologists have combined 15 electrolysis cells to form a stack. The individual cells are made from a special plastic using an injection molding process suitable for series production. This reduces the costs for the bipolar plates by around 90 percent and the weight of the electrolysis stack is halved.
To fill the metal hydride storage, the hydrogen is supplied at a pressure of 10 bar and dried maintenance-free in a membrane module. A second, down-stream drying stage increases the service life by a factor of eight.

A microcontroller-based control concept, which has also been developed at Fraunhofer ISE, ensures that the system operates reliably at the push of a button. A comprehensive safety analysis underlies the system’s hardware component-based safety strategy.
“Micro fuel cell systems, as a technology of the future, have considerable potential for powering off-grid and portable electronic devices,” says Dr. Christopher Hebling, head of the Department for Energy Technology at Fraunhofer ISE. In this context, the institute presents, besides the mini-electrolyzer, its latest work in the field of fuel cell development. “We are currently expanding the field of application of our micro fuel cells to extreme temperature ranges and thus making them suitable for outdoor use,” explains Christopher Hebling. Whether with icy temperatures of -20° C or a heat wave of +40° C, the micro fuel cell system always starts.

The miniaturization of the electrolyzing system and the micro fuel cell system for outdoor applications were supported by the German Federal Ministry of Economics and Technology and conducted in collaboration with partners from industry and research. The project supporting body is the VDI/VDE-IT.

Hannover Messe trade fair, 24-28 April 2006, Fraunhofer ISE
Hall 13 ‘Hydrogen + Fuel Cells’, Booth E90/2

Micro-energy technology is one of the Fraunhofer-Gesellschaft’s twelve ‘signposts to tomorrow’s markets’. In addition, an overview of the Fraunhofer activities in this area, under the responsibility of Fraunhofer ISE, can be found at the Fraunhofer-Gesellschaft’s Booth D22 in hall 2.