Patent ID: 7851105

Claim:
An electrochemical fuel cell stack comprising: a plurality of electrochemical fuel cells, each comprising: an anode and a cathode; an anode plate having an active surface facing the anode and an oppositely facing non-active surface, wherein the anode plate active surface comprises a plurality of parallel linear fuel flow field channels, and the anode plate further comprises a fuel supply manifold opening and a fuel supply plenum that fluidly connects the fuel flow field channels to the fuel supply manifold opening, a fuel supply backfeed channel at least partially formed on the non-active surface of the anode plate, and a fuel supply backfeed port extending through the anode plate that fluidly connects the fuel supply backfeed channel and the fuel supply plenum, wherein the fuel supply backfeed channel of each fuel cell is also at least partially formed on the non-active surface of the adjoining cathode plate of an adjacent fuel cell; and a cathode plate having an active surface facing the cathode and an oppositely facing non-active surface, wherein the cathode plate active surface comprises a plurality of parallel linear oxidant flow field channels, and the cathode plate further comprises an oxidant supply manifold opening and an oxidant supply plenum that fluidly connects the oxidant flow field channels to the oxidant supply manifold opening, wherein, with respect to each adjoining anode plate and cathode plate in a pair of adjacent fuel cells in the stack, the fuel and oxidant supply plenums of the adjoining anode and cathode plates are staggered so as not to overlap in the direction perpendicular to the plane of the fuel cells, wherein the total height of the fuel supply plenum plus the fuel supply backfeed channel is greater than the thickness of the anode plate.