Gas diffusion member, gas diffusion unit, and fuel cell
A gas diffusion member which can reduce internal resistance of a fuel cell. A gas diffusion member arranged between a separator and a catalyst layer of a fuel cell, including: a porous material layer; and a conductive material layer; wherein: the porous material layer is formed of a conductive porous material; the conductive material layer is formed of a conductive material; and the conductive material layer is arranged on a surface of the porous material layer on a side of the separator and is provided so that pores of the porous material layer are filled with the conductive material.
1 . A gas diffusion unit comprising a gas diffusion member and a separator, wherein the gas diffusion member is adapted to be arranged between the separator and a catalyst layer of a fuel cell, the gas diffusion member comprising:
a porous material layer; and
a conductive material layer, wherein:
the porous material layer is formed of a conductive porous material;
the conductive material layer is formed of a conductive material;
the conductive material layer is arranged on a surface of the porous material layer on a side of the separator and is provided so that pores of the porous material are filled with the conductive material;
the gas diffusion member is adhered to the separator via the conductive material; and
a thickness of a part of the conductive material layer formed inside the porous material layer is defined as T 1 and the thickness of the part formed outside the porous material layer is defined as T 2 , and a value T 2 /T 1 is 0.5 or less.
2 . The gas diffusion unit of claim 1 , wherein the porous material layer comprises a groove on the surface on the side of the separator as a gas flow path.
3 . The gas diffusion unit of claim 1 , wherein a microporous layer is provided on a surface of the porous material layer on a side of the catalyst layer.
4 . The gas diffusion unit of claim 1 , wherein the conductive material is formed of a resin in which conductive particles are dispersed.
5 . The gas diffusion unit of claim 1 , wherein a thickness of the conductive material layer is 1 to 100 μm.
6 . The gas diffusion unit of claim 1 , wherein a gasket arranged to surround the gas diffusion member is fixed to the separator.
7 . A fuel cell, comprising:
a cathode gas diffusion unit, a catalyst-coated membrane, and an anode gas diffusion unit in this order;
wherein:
the catalyst-coated membrane comprises a cathode catalyst layer, an electrolyte membrane and an anode catalyst layer in order from a side of the cathode gas diffusion unit; and
the cathode gas diffusion unit and the anode gas diffusion unit are each the gas diffusion unit of claim 1 .
8 . The fuel cell of claim 7 , wherein:
a cathode gasket arranged to surround the cathode gas diffusion member of the cathode gas diffusion unit is fixed to the separator of the cathode gas diffusion unit; and
an anode gasket arranged to surround the anode gas diffusion member of the anode gas diffusion unit is fixed to the separator of the anode gas diffusion unit.