POROUS SEPARATOR FOR FUEL CELL

A porous separator for a fuel cell is provided and features the shape of a passage aperture formed in a flow field plate. The modified shape of the passage aperture minimizes destruction of a gas diffusion layer or a membrane electrode assembly attributable to stress concentration. The porous separator has a flow field plate that includes a first contact portion that is in contact with a gas diffusion layer or a membrane electrode assembly; a second contact portion that is in contact with a coolant channel; and a connection portion that is connected between the first contact portion and the second contact portion. Additionally, a passage aperture is formed in the connection portion, wherein a portion of an inside surface of the passage aperture protrudes toward a center of the passage aperture.