German researchers develop lightweight fuel cells

People trapped in earthquakes could be easier to find with the help of a mini helicopter powered by very light fuel cells.

 

German researchers at the Technical University of Berlin and the Fraunhofer Institute for Reliability and Microintegration IZM in Berlin have developed a fuel cell that weighs only 30 grams and has an output of 12 watts - giving a power density of 400W/kg that has only previously been seen in much larger systems. As well as also being used in contaminated areas the fuel cell could be used as a charging point for laptop computers and cell phones.

 

To achieve a high enough power output manufacturers usually stack fuel cells consisting of a structure of several metal plates each containing one channel for air and another for hydrogen - making the fuel stack very heavy.

 

The researchers reduced the weight by using very thin, planar fuel cells. IZM team leader Dr. Robert Hahn explained, "We have replaced the metal plates by lightweight plastic spacers." The researchers have no need for an additional pump to provide an adequate air supply: The wind generated by the helicopter's rotor blades goes directly into the air vents. The scientists had to devise a solution for the hydrogen supply, too, as a conventional pressure tank would be too heavy for the helicopter. "We have built a small reactor containing solid sodium borohydride. If we inject water, this produces hydrogen," continued Hahn.

 

A prototype of the lightweight fuel cell has already been built by the team and they expect the mini-helicopter to take off with it later next year.

 

For more attend Printed Electronics USA 2008.

 

Reference: Fraunhofer Institute for Reliability and Microintegration IZM