Patent ID: 10637069

Abstract:
The purpose of the present invention is to provide a carbon sheet that is suitably employed in a gas-diffusion-electrode substrate that has excellent flooding resistance and with which it is possible to suppress internal peeling of the carbon sheet. In order to achieve the aforementioned purpose, the present invention has the following configuration. Specifically, provided is a porous carbon sheet containing carbon fibers and a binder, wherein, in a section between a surface on one side of the carbon sheet and a surface on the other side thereof, when layers obtained by dividing, under compression, the carbon sheet into six equal parts in the thickness direction are assumed to be layer 1, layer 2, layer 3, layer 4, layer 5, and layer 6, in order starting from the layer including the surface on the one side to the layer including the surface on the other side, the layer in which the packing ratio under compression is the greatest is layer 2, and the relationships of the packing ratios under compression among layer 2, layer 3, layer 4, layer 5, and layer 6 are such that layer 2 has the greatest packing ratio, and layer 3 has the second-greatest packing ratio.