Gas diffusion layer for fuel cell, fuel cell, and method of manufacturing gas diffusion layer for fuel cell

• US 9,525,187 B2
• Filed: 01/31/2013
• Issued: 12/20/2016
• Est. Priority Date: 02/08/2012
• Status: Active Grant

• Current Assignee: Toyota Boshoku Kabushiki Kaisha (Toyota Motor Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Boshoku Kabushiki Kaisha (Toyota Motor Corporation), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Fujito, Riri, Tsubosaka, Kenji, Fujii, Kenta
• Primary Examiner(s): Barcena, Carlos
• Assistant Examiner(s): Haske, Wojciech
• Application Number:
  US14/377,232
• Publication Number:
  US 20160013503A1
• Time in Patent Office: 1,419 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/8807 Gas diffusion layers
• CPC Class Codes: H01M 4/8817 Treatment of supports before application of the catalytic active composition coated porous composites H01M8/0245
• CPC Class Codes: H01M 4/96 Carbon-based electrodes
• CPC Class Codes: H01M 8/0234 Carbonaceous material
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

Gas diffusion layers, that is, an anode-side gas diffusion layer and a cathode-side gas diffusion layer that are attached to an MEA have irregularities on fiber surfaces of carbon fibers deposited in a layer thickness direction. These irregularities on the fiber surfaces are formed when the fibers are extruded from an extrusion nozzle to be spun.

Claims

1. A gas diffusion layer for a fuel cell, comprising carbon fibers deposited in a layer thickness direction of the gas diffusion layer, wherein

the gas diffusion layer has three or more layers in each of which the carbon fibers are deposited in the layer thickness direction,

the carbon fibers having irregularities on fiber surfaces thereof, and

the carbon fibers of an inner layer are larger in size or larger in number than the irregularities on the fiber surfaces of the carbon fibers of a surface layer.

2. The gas diffusion layer according to claim 1, wherein

the irregularities on the fiber surfaces of the carbon fibers on at least one surface layer side of the gas diffusion layer are smaller in size or smaller in number than the irregularities on the fiber surfaces of the carbon fibers in regions other than the surface layer side.

3. The gas diffusion layer according to claim 1, wherein

the carbon fibers are fused to one another at intersecting spots of the carbon fibers.

4. The gas diffusion layer according to claim 1, wherein

the carbon fibers include hollow fibers.

5. The gas diffusion layer according to claim 4, wherein

a porosity of the hollow fibers is from 30 to 90%.

6. The gas diffusion layer according to claim 1, wherein

the irregularities extend in a direction perpendicular to a direction of the carbon fibers.

7. The gas diffusion layer according to claim 6, wherein

the irregularities are generally hemispherical with a diameter that is equal to or larger than 3 μ

m and equal to or smaller than 30 μ

m.

8. The gas diffusion layer according to claim 1, wherein

the irregularities per a unit area of the fiber surface of the carbon fibers range in number from 0.0005/μ

m² to 0.05/μ

m².

9. A fuel cell comprising:

a membrane electrode assembly including an electrolyte membrane and electrodes each of which are attached to both faces of the electrolyte membrane; and

a gas diffusion layer that is attached to the membrane electrode assembly, the gas diffusion layer including carbon fibers deposited in a layer thickness direction of the gas diffusion layer, wherein

the gas diffusion layer has three or more layers in each of which the carbon fibers are deposited in the layer thickness direction,

the carbon fibers having irregularities on fiber surfaces thereof, and

the carbon fibers of an inner layer are larger in size or larger in number than the irregularities on the fiber surfaces of the carbon fibers of a surface layer.