Patent ID: 7585577

Claim:
A monopolar fuel cell stack comprising a plurality of sealed unit cells couple together in a rigid assembly without use of top or bottom cover plates or tie rods, each unit cell comprising: a first cathode; a first membrane assembly disposed adjacent to the first cathode; an anode plate disposed adjacent to the first membrane assembly, the anode plate having an anode and an internal channel defined therein for flow of fuel through the anode plate; an inlet manifold coupled to the anode plate and communicating with the channel within the anode plate; an outlet manifold coupled to the anode plate and communicating with the channel within the anode plate, the fuel flowing from the inlet manifold through the channel in contact with the anode plate and flowing out through the outlet manifold; a second membrane assembly disposed adjacent to the anode plate; and a second cathode disposed adjacent to the second membrane assembly, wherein the inlet and outlet manifolds of each unit cell are arranged and configured to rigidly connect to the inlet and outlet manifolds respectively of an adjacent one of the plurality of unit cells to define a common inlet manifold comprised of all of the inlet manifolds of the plurality of the unit cells when the unit cells are coupled together and to space the unit cells apart from each other in an open stack to expose the cathodes and first and second membrane assemblies to oxygen or air, and to define a common outlet manifold comprised of all of the outlet manifolds of the unit cells when coupled together in the open stack, the rigid connection of the inlet and outlet manifolds of each unit cell to the inlet and outlet manifolds of an adjacent unit cell fixing the plurality of unit cells into the open stack as the sole means for retaining the open stack in the rigid assembly.