Abstract: An electrochemical fuel cell having reactant flow passages with a non-uniform design to increase reactant access to an adjacent fluid distribution layer at the outlet region as compared to the inlet region. In an embodiment, at least one reactant flow passage is narrower at the inlet than at the outlet, with a substantially constant cross-sectional area maintained along its length. Coolant channels may optionally be incorporated in the fluid flow plate to provide increased cooling at the reactant inlet. The plates may vary in thickness and run in counter-flow to improve efficient stacking of the fuel cells in a fuel cell stack with reactant passages of varying depth. In another embodiment, electrically conductive, masking foil covers a portion of at least one reactant flow passage in the inlet region, but does not extend the length of the passage.

Abstract: An electrochemical fuel cell having reactant flow passages with a non-uniform design to increase reactant access to an adjacent fluid distribution layer at the outlet region as compared to the inlet region. In an embodiment, at least one reactant flow passage is narrower at the inlet than at the outlet, with a substantially constant cross-sectional area maintained along its length. Coolant channels may optionally be incorporated in the fluid flow plate to provide increased cooling at the reactant inlet. The plates may vary in thickness and run in counter-flow to improve efficient stacking of the fuel cells in a fuel cell stack with reactant passages of varying depth. In another embodiment, electrically conductive, masking foil covers a portion of at least one reactant flow passage in the inlet region, but does not extend the length of the passage.

Abstract: An electrochemical fuel cell comprises at least one fluid distribution layer comprising a substantially fluid impermeable sheet material which is rendered fluid permeable at least in the active area through the non-uniform application of perforations. In some embodiments, the size of the perforations in the fluid distribution layer increases in the reactant flow direction. In other embodiments, the density of the perforations in the fluid distribution layer increases in the reactant flow direction. The fluid permeability of the fluid distribution layer may also increase from the inlet to a mid-point between the inlet and the outlet and then decrease thereafter to the outlet.