Glass Fiber Mesh Method of Joining for Solid Oxide Fuel Cells
Among the critical issues in designing and fabricating a solid oxide fuel cell (SOFC) stack are the materials and techniques for hermetically sealing the metal and/or ceramic components. Researchers at PNNL have developed a high-strength seal incorporating metal mesh and glass fibers. The unique method results in a durable, insulating seal that resists the damages commonly brought on by thermal cycling.Description
The seal uses microscopic metal screening spot welded to the metal surface that serves as an anchor for the heated glass. Ceramic fibers are applied between the two surfaces being joined during thermal cycling providing additional strength in the seal. The heated glass bonds to the anchors and the fibers hermetically forcing the energy to pass through the ceramic layer of the stack; this maximizes the energy efficiency of the cell. The insulating feature also allows the stack to withstand heating variations (stacks typically do not heat uniformly) that commonly create seal failures in fuel cells.
The Glass Fiber Mesh Seal method is ideal for applications needing quick thermal cycling (responsiveness) such as transportation or stationary applications such as high-use distributed energy sources.
- Stronger than typical glass seals
- Insulating features provide for better energy efficiency
- Quick thermal cycling allows power to be delivered more quickly.
- High-use distributed energy sources
|Title and Abstract||
Joint with application in electrochemical devices
A joint for use in electrochemical devices, such as solid oxide fuel cells (SOFCs), oxygen separators, and hydrogen separators, that will maintain a hermetic seal at operating temperatures of greater than 600.degree. C., despite repeated thermal cycling excess of 600.degree. C. in a hostile operating environment where one side of the joint is continuously exposed to an oxidizing atmosphere and the other side is continuously exposed to a wet reducing gas. The joint is formed of a metal part, a ceramic part, and a flexible gasket. The flexible gasket is metal, but is thinner and more flexible than the metal part. As the joint is heated and cooled, the flexible gasket is configured to flex in response to changes in the relative size of the metal part and the ceramic part brought about by differences in the coefficient of thermal expansion of the metal part and the ceramic part, such that substantially all of the tension created by the differences in the expansion and contraction of the ceramic and metal parts is absorbed and dissipated by flexing the flexible gasket.
|Pacific Northwest National Laboratory||09/14/2010
|Technology ID||Development Stage||Availability||Published||Last Updated|
|14163||Prototype - Reduced to practice||Available - Available for licensing in all fields of use||09/10/2010||09/10/2010|