Laminated fluid flow field assembly for electrochemical fuel cells
AssigneeBallard Power Systems Inc.
InventorsKirk B. Washington, David P. Wilkinson, Henry H. Voss
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Abstract
A laminated fluid flow field assembly for an electrochemical fuel cell comprises a separator layer and a stencil layer. The separator layer is formed of electrically conductive, substantially fluid impermeable sheet material. The stencil layer is formed of electrically conductive sheet material, and has a fluid inlet and at least one opening extending between its major surfaces and in fluid communication with the fluid inlet. The separator layer and the stencil layer are consolidated along one of their major surfaces. In operation, the separator layer and the stencil layer cooperate to form an open-faced channel for conducting pressurized fluid introduced at the fluid inlet.
Claims17
A laminated fluid flow field assembly for an electrochemical fuel cell, said assembly comprising:
- a separator layer formed of electrically conductive, substantially fluid impermeable sheet material, said separator layer having two oppositely facing major surfaces;
- a stencil layer formed of electrically conductive sheet material, said stencil layer having two oppositely facing major surfaces, said stencil layer having a fluid inlet formed therein and having at least one opening formed therein extending between the major surfaces thereof, said at least one opening in fluid communication with said fluid inlet;
- means for consolidating said separator layer and said stencil layer along one of their respective major surfaces,
- whereby said separator layer and said stencil layer cooperate to form at least one open-faced channel for conducting pressurized fluid introduced at said fluid inlet.
An electrochemical fuel cell for converting a fluid fuel stream and a fluid oxidant stream to a reaction product stream and electrical energy, said fuel cell comprising:
- first and second laminated fluid flow field assemblies, each of said assemblies comprising:
- a separator layer formed of electrically conductive, substantially fluid impermeable sheet material, said separator layer having two oppositely facing major surfaces;
- a stencil layer formed of electrically conductive sheet material, said stencil layer having two oppositely facing major surfaces, said stencil layer having a fluid inlet formed therein and having at least one opening formed therein extending between the major surfaces thereof, said at least one opening in fluid communication with said inlet;
- means for consolidating said separator layer and said stencil layer along one of their respective major surfaces;
- whereby said separator layer and said stencil layer cooperate to form at least one open-faced channel for conducting pressurized fluid introduced at said inlet;
- a membrane electrode assembly interposed between said first and second laminated fluid flow field assemblies, said membrane electrode assembly comprising:
- an anode having a catalyst associated therewith to render a region of said anode electrocatalytically active wherein cations are produced from said fluid fuel stream;
- a cathode having a catalyst associated therewith to render a region of said cathode electrocatalytically active wherein an electrochemical reaction between said cations and said fluid oxidant stream is promoted;
- a solid polymer ion exchange membrane disposed between said anode assembly and said cathode assembly, said membrane facilitating the migration of cations from said anode assembly to said cathode assembly and isolating said fluid fuel stream from said fluid oxidant stream;
- an electrical path for conducting electrons formed at said anode assembly to said cathode assembly.
A method of fabricating a laminated fluid flow field assembly for an electrochemical fuel cell, the method comprising the steps of:
- providing a separator layer formed of electrically conductive, substantially fluid impermeable sheet material, said separator layer having two oppositely facing major surfaces;
- providing a stencil layer formed of electrically conductive sheet material, said stencil layer having two oppositely facing major surfaces,
- forming a fluid inlet in said stencil layer;
- forming at least one opening extending between the major surfaces of said stencil layer, said at least one opening in fluid communication with said inlet;
- consolidating said separator layer and said stencil layer along one of their respective major surfaces.
Dependencies are inferred from the claim text.