Mechanical characterization and modeling of electrolyte membranes in electrolyte-supported SOFCs

Abstract

Planar Solid Oxide Fuel Cells (SOFCs) are made up of repeating sequences of thin layers of energy producing ceramics, seals, and current collectors. For electro-chemical reasons it is best to keep the ceramic layers as thin as possible, which also means that the cells are more susceptible to damage during production, assembly, and operation. The latest-generation electrolyte-supported SOFCs have a honeycomb-type support structure. The electrolyte membranes, which are much smaller in thickness than they are in area, require a two-scale approach for finite element modeling; the smaller scale focuses on analyzing a representative area of the cell, while the larger scale examines the cell as a whole. To provide the material data for the models, an array of experimental techniques are needed. The small scale model requires bulk elastic properties of the electrolyte material, which are measured over a range of temperatures using a sonic resonance technique. This model then outputs "effective" properties for the large scale, which must be experimentally validated using four-point bend tests on representative samples. Additionally, a series of compression tests are performed on cells for validate the performance of electrolytes in the context of a stack. ©2010 Society for Experimental Mechanics Inc.