Solid Oxide Fuel Cell (SOFC) - Westinghouse"
This diagram shows the arrangement of components in the tubular solid oxide fuel cell. Air is channeled into the cell stack and through the center of each tube. The innermost layer of the tube is the cell cathode and is surrounded by the electrolyte (middle layer). Fuel flows over the outer layer that serves as the anode.
Bundles of tubes are joined together into modules to make a fuel cell stack. The modular nature of fuel cells is one of their strengths, because power plants can add modules as they need them and keep unused capacity to a minimum