An all-ceramic interconnect for use in solid-oxide fuel cell stacks

This article summarizes a unique approach in which all-ceramic interconnects are used in place of metal interconnects in solid-oxide fuel cell (SOFC) stacks. The approach combines advanced SOFC materials with the manufacturing technology and infrastructure established for multilayer ceramic (MLC) packaging for the microelectronics industry. The MLC interconnect is fabricated using multiple layers of yttria-stabilized zirconia (YSZ) tape, with each layer containing conductive vias to provide for electrical current flow through the interconnect. The all-ceramic interconnect design facilitates uniform distribution of air and fuel gas to the respective electrodes of adjacent cells. The multilayer interconnects are fabricated using traditional MLC manufacturing processes. A detailed description of the processes for facilitating the all-ceramic interconnect is presented. To aid in moving from prototype fabrication to commercialization of these fuel cell systems, a detailed cost model has been used as a roadmap for commercial stack development. Cost model projections are presented for three different interconnect footprint sizes. These projections show an SOFC stack cost at less than $150 per kilowatt for the optimized SOFC stack design produced at high volume.