One of the critical issues in designing and fabricating a high-performance, planar, solid oxide fuel cell (SOFC) stack is the development of the appropriate materials and techniques for hermetically sealing the metal and ceramic components.  

Researchers at PNNL have developed a foil-based sealing approach that appears to offer good hermetic and mechanical integrity, while minimizing the generation of high stresses in either of the joint’s substrate materials. Based on the concept’s viability, demonstrated in prior experimental work, numerical analyses have been conducted to evaluate the behavior and benefits of the seal in a configuration prototypic of current SOFC stack designs.  

The results of these tests indicated that the foil seal is able to accommodate a significant degree of thermal mismatch strain between the metallic support structure and the ceramic cell via elastic deformations of the foil and plasticity in the foil-to-cell braze layer. Consequently the cell stresses in this type of seal are predicted to be much lower than those in the glass-ceramic and brazed designs, which is expected to lead to improved stack reliability.