Patent ID: 8580460
Filing Date: 2013-11-12
Classification: H01M,Y02E

Abstract:
1. A flow field plate assembly for a fuel cell stack having a plurality of fuel cells, each comprising a membrane electrode assembly (MEA), the flow field plate assembly comprising: a first flow field plate having first and second reactant manifold openings and being positionable on an anode side of the MEA of a first fuel cell, a first side of the first flow field plate having at least one reactant flow field channel adapted to direct a fuel to an anode electrode layer of the MEA; and a second flow field plate having third and fourth reactant manifold openings and being positionable on a cathode side of the MEA of a second fuel cell, adjacent the first fuel cell, a first side of the second flow field plate having at least one reactant flow field channel adapted to direct an oxygen-containing gas to a cathode electrode layer of the MEA; wherein, the third reactant manifold opening is positioned adjacent the first reactant manifold opening, forming a fuel manifold opening; the fourth reactant manifold opening is positioned adjacent the second reactant manifold opening, forming an oxidant manifold opening; at least one of the fuel and oxidant manifold openings has a cross-sectional geometry that is configured to have a region for flow of reactants and a region substantially isolated from flow of reactants, wherein said region substantially isolated from flow of reactants tapers to provide a region which draws water by capillary force such that when the flow field plate assembly is installed in the fuel cell stack and the fuel cell stack is in operation, capillary forces direct liquid migration toward said regions substantially isolated from a flow of reactants; the flow field plate assembly further comprises at least one back-feed channel formed between the first and second flow field plates in fluid communication with at least one of the fuel and oxidant manifold openings and at least one of the reactant flow field channels; the back-feed channel has a region for flow of reactants and a region substantially isolated from flow of reactants, wherein said region substantially isolated from flow of reactants has at least one of a cross-sectional geometry and a longitudinal geometry configured to taper to create high and low capillary forces that direct liquid migration toward said regions substantially isolated from a flow of reactants, when the flow field plate assembly is installed in the fuel cell stack and the fuel cell stack is in operation; and at least a portion of the back-feed channel is fabricated from a hydrophobic material exhibiting an advancing contact angle of at least 90 degrees and a receding contact angle of at least 70 degrees in response to contact with water.