Abstract - Analytic Power Corp., 9360857 A fuel cell is a device used to convert chemical energy into electrical energy through the electrochemical oxidation of a fuel species. The objective of this SBIR Phase I research program is to design, build and test a new solid oxide fuel cell (SOFC) and bipolar plate. SOFC power plants have a potential efficiency of greater than 60%, can eliminate NOx emissions, reduce carbon dioxide emissions, and have fewer moving parts. In the past, SOFC's have been plagued with thermal expansion problems, sealing and thermal cycling problems, corrosion problems, high electrolyte resistivity, and poor theoretical open circuit potential. This project will test an ultra thin (5-10 micron) oxide ion conducting fuel cell which can operate at 650 C. This temperature is low enough to mitigate corrosion, and thermal expansion problems yet it is high enough to permit internal reforming of hydrocarbon fuels. It is low enough to permit the use of highly reactive, low cost cathode catalysts such as silver. Because this approach reduced the thickness of the electrolyte, it is possible to reduce the operating temperature of the cell and maintain high performance. By using fabrication processes which are common in the electronics industry, a low cost product can be assured. To date bipolar cell stacking configurations have been the only arrangement successfully used for fuel cells. The use of metal bipolar plates introduces a thermal expansion problem into the stack structure. The coefficient of thermal expansion of the ceramic components is much lower than the coefficient of thermal expansion of the metal bipolar plate. This problem is mitigated here by using a bipolar plate and cell frame structure which deals with the differential thermal expansion via a mechanical design solution. Steel components can be corrosion protected with silver plating. All parts can then be brazed together. This prevents the formation of electronically insulating oxide layers on bipolar plate components.
