Patent ID: 8828622

Claim:
A power generating cell comprising: a rectangular frame; an electrolyte membrane accommodated inside the frame; a positive electrode layer and a negative electrode layer provided to contact opposing surfaces of the electrolyte membrane; and a positive electrode-side separator and a negative electrode-side separator provided to contact opposing surfaces of the frame and the positive and negative electrode layers, respectively, the positive electrode-side separator and the negative electrode-side separator each comprising: a plurality of linearly extending protrusions; and a plurality of flat walls alternately arranged with the plurality of linearly extending protrusions, wherein each protrusion of the plurality of linearly extending protrusions is defined by a pair of side walls and a top wall, the plurality of linearly extending protrusions are parallel to each other, a gas passage forming groove is defined between each adjacent pair of the plurality of linearly extending protrusions, a belt-like groove is provided on an inner surface of each flat wall of the plurality of flat walls that faces the corresponding gas passage forming groove, each belt-like groove is provided in a middle position with respect to a widthwise direction of the corresponding flat wall, the belt-like grooves are parallel with the plurality of linearly extending protrusions, each belt-like groove in each flat wall is a recessed portion in each flat wall, each recessed portion having a thickness that is thinner than a thickness of each flat wall, a width between corresponding side walls of each protrusion increases toward the top wall so that each side wall is inclined relative to each flat wall, a fluid supply hole is provided at an upper portion of each of the positive electrode-side separator and the negative electrode-side separator to supply a fluid to each gas passage forming groove through a common fluid supply passage that communicates with each gas passage forming groove, a fluid discharge hole is provided at a lower portion of each of the positive electrode-side separator and the negative electrode-side separator to discharge the fluid supplied to each gas passage forming groove through a common fluid discharge passage that communicates with each gas passage forming groove, an auxiliary belt-like groove is provided in a middle portion in a widthwise direction of each top wall, each auxiliary belt-like groove is parallel with each protrusion, and each auxiliary belt-like groove in each top wall is a recessed portion in each top wall, each recessed portion having a thickness that is thinner than a thickness of each top wall.