Power cells to the people

Fraunhofer researchers are working to make multi-fuel, high temperature ceramic fuel cells affordable on the mass market for use as portable power generators.

Professor Alexander Michaelis, director of the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS) in Dresden, said, “Ceramic high-temperature fuel cells are ideal as mobile power generators for motor homes, boats, trucks or cars. They also have stationary applications for generating electricity, heating and cooling, or in agriculture for generating energy from biogas.”

The IKTS researchers are developing cost-effective, long-lasting stacks, the heart of a high-temperature fuel cell, suited to 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.

The ceramic cells’ main advantage over the polymers used in low-temperature fuel cells is that as well as pure hydrogen they can also generate power from methane, gasoline, diesel, natural gas or biogas. The process is fairly simple from an engineering viewpoint, which makes the end product economical. Used as part of a combined heat/cooling and power system, ceramic fuel cells can achieve an efficiency of 90 per cent, outperforming alternative technologies.

However, the stacks inside the fuel cell need to withstand major stresses, with operating temperatures reaching up to 1,000^oC. In effect, a high reducing atmosphere is created on the combustion gas side of the ceramic cells as a counterpoint to the high oxidising atmosphere on the air side.

Together with industry partners HC Starck, a subsidiary of Bayer, and Webasto, a team at the IKTS is developing composite materials made out of metal, ceramics and glass. These materials are suitable for building low-cost, robust stacks and have already achieved a service life of over 5,000 hours. The new stack design is due to go into series production shortly.