Abstract: The invention relates to a bipolar plate (1) for a fuel cell stack having two layers (2, 3) which each have an anode-side or cathode-side flow area (9) on their surfaces facing away from one another, wherein aligned media inlet openings (4, 13, 15) and media outlet openings (5, 14, 16) are provided in the two layers (2, 3), wherein each of the media inlet and outlet openings (4, 5, 13, 14, 15, 16) are connected to channels (6) between the inner surfaces of the two layers (2, 3) facing toward one another, and wherein the channels (6) assigned to the anode side and the cathode side are each connected to the anode-side or cathode-side flow areas via openings (7) in the respective layer (2, 3). The bipolar plate according to the invention is characterized in that the material of the respective layer (2, 3) is reinforced in the sections (17) opposite to the openings (7) of the other layer (3, 2).

Abstract: Flow field plates in solid polymer electrolyte fuel cells can be subject to ice blockages in certain areas during freeze start-up, e.g. the backfeed ports and slots used in some flow field plate designs which connect an outlet plenum channel for a reactant to its outlet. By incorporating a similar and adjacent relief backfeed port, slot and plenum channel arrangement in which the relief plenum channel is separated from the outlet plenum channel by a landing, a relief outlet for the reactant is provided through the adjacent gas diffusion layer.

Abstract: Flow field plates in solid polymer electrolyte fuel cells can be subject to ice blockages in certain areas during freeze start-up, e.g. the backfeed ports and slots used in some flow field plate designs which connect an outlet plenum channel for a reactant to its outlet. By incorporating a similar and adjacent relief backfeed port, slot and plenum channel arrangement in which the relief plenum channel is separated from the outlet plenum channel by a landing, a relief outlet for the reactant is provided through the adjacent gas diffusion layer.

Abstract: Improved bipolar plates comprising complex features can be manufactured for fuel cells in a simple, low cost manner by starting with an appropriate extruded piece. The complex features include one or more fluid ports which connect to channels internal to the bipolar plate. The method includes extruding a continuous sheet with appropriate linear channels on each surface of the sheet as well as within the sheet, transversely cutting the sheet, machining a fluid port or ports through the sheet to intersect with appropriate internal linear channels, machining at least two sealing ports through the sheet to intersect with the internal linear channels on opposite sides of the fluid ports, and applying sealant into the sealing ports in order to make appropriate seals to the internal linear channels.

Abstract: Hybrid bipolar plate assemblies comprising a metal subassembly and a carbonaceous flow field insert can be used to provide for greater current densities from smaller volume fuel cell stacks. In particular, such hybrid bipolar plate assemblies allow for the combination of preferred oxidant channel structures, which can be formed in carbonaceous oxidant flow field inserts, with preferred smaller bipolar plate assembly thicknesses, which are possible with the use of metal plate subassemblies.