Jul 25 2006
“Ceramic high-temperature fuel cells will soon be a mass market,” forecasts Professor Alexander Michaelis, director of the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden. “They are ideal as mobile power generators for motor homes, boats, trucks or cars, as well as in stationary applications for generating electricity, heating and cooling, or in agriculture for generating energy from biogas.”
By developing cost-effective, long-lasting stacks, the heart of a high-temperature fuel cell, IKTS researchers have now created conditions for commercial applications. Stacks are made up of thin ceramic plates on the surface of which fuels are converted directly into electrical power through an electrochemical process. Compared with the polymers used in low-temperature fuel cells, these ceramic cells have one distinct advantage: apart from pure hydrogen, which is difficult to obtain in any case, they can also generate power from methane, gasoline, diesel, natural gas or biogas. The process is fairly simple from an engineering viewpoint and therefore cost-effective. Efficiency of more than 90 percent can be achieved as part of a combined heat/cooling and power system – outperforming alternative technologies.
However, the stacks inside the fuel cell need to withstand major stresses with operating temperatures reaching up to 1 000 degrees Celsius. In effect, a high reducing atmosphere is created on the combustion gas side of the ceramic cells as a counterpoint to the high oxidizing atmosphere on the air side. Developing materials that can constantly withstand these kinds of aggressive conditions is a challenge for seasoned materials researchers. Together with industry partners H.C. Starck GmbH, a subsidiary of Bayer AG, and Webasto AG, a team at the IKTS is developing composite materials made out of metal, ceramics and glass. These materials are ideal for building low-cost, robust stacks – a service life of over 5,000 hours has already been achieved. The new stack design is due to go into series production shortly.