A fuel cell stack includes: a separator comprising channels and lands alternately repeated; and a gas diffusion layer in contact with the separator for transferring gas to a membrane-electrode assembly. The gas diffusion layer has a fiber arrangement structure having a predetermined directionality beneath the lands adjacent to opposite lateral sides of the channels based on a central portion of the channels to guide a transfer passage of the gas.

A fuel cell stack includes: a separator comprising channels and lands alternately repeated; and a gas diffusion layer in contact with the separator for transferring gas to a membrane-electrode assembly. The gas diffusion layer has a fiber arrangement structure having a predetermined directionality beneath the lands adjacent to opposite lateral sides of the channels based on a central portion of the channels to guide a transfer passage of the gas.

A cathode-side gas flow path of a cell that forms part of a fuel cell is formed by a first expanded metal arranged on a gas inlet side, and a second expanded metal arranged on a downstream side. The first expanded metal is such that mesh is arranged in a straight line, and gas that flows on a gas diffusion layer side is separated from gas that flows on a separator side. The gas flowrate on the gas inlet side is reduced, so the amount of produced water that is carried away is reduced. As a result, the gas inlet side is inhibited from becoming dry at high temperatures.

A cathode-side gas flow path of a cell that forms part of a fuel cell is formed by a first expanded metal arranged on a gas inlet side, and a second expanded metal arranged on a downstream side. The first expanded metal is such that mesh is arranged in a straight line, and gas that flows on a gas diffusion layer side is separated from gas that flows on a separator side. The gas flowrate on the gas inlet side is reduced, so the amount of produced water that is carried away is reduced. As a result, the gas inlet side is inhibited from becoming dry at high temperatures.

A method for manufacturing a separator assembly includes a preparation step for preparing a first separator, a second separator, and an elastic member; a first placement step for positioning the elastic member and placing the same on a placement surface; a second placement step for positioning the first separator in relation to the elastic member, and placing the first separator so as to overlap the elastic member; and a joining step for joining the elastic member and first separator which have been positioned and made to overlap. In the second placement step, the first separator is made to overlap the elastic member while first positioning members for positioning the elastic member are made to retract into the placement surface.

A method for manufacturing a separator assembly includes a preparation step for preparing a first separator, a second separator, and an elastic member; a first placement step for positioning the elastic member and placing the same on a placement surface; a second placement step for positioning the first separator in relation to the elastic member, and placing the first separator so as to overlap the elastic member; and a joining step for joining the elastic member and first separator which have been positioned and made to overlap. In the second placement step, the first separator is made to overlap the elastic member while first positioning members for positioning the elastic member are made to retract into the placement surface.

A fuel cell separator capable of surely discharging produced water, and a method and apparatus for producing the same. The fuel cell separator is formed in a wave shape with recesses and projections alternately arranged in a first direction, the recesses forming reactant gas channels together with a membrane electrode assembly and the projections abutting the membrane electrode assembly, in which on a surface of the fuel cell separator that is adapted to face the membrane electrode assembly, a plurality of first grooves extending in the first direction along the corrugation of the recesses and projections is disposed at intervals from each other in a second direction orthogonal to the first direction, and a second groove extending in the second direction and communicating with the plurality of first grooves is disposed in the bottom portion of each recess.

A fuel cell separator capable of surely discharging produced water, and a method and apparatus for producing the same. The fuel cell separator is formed in a wave shape with recesses and projections alternately arranged in a first direction, the recesses forming reactant gas channels together with a membrane electrode assembly and the projections abutting the membrane electrode assembly, in which on a surface of the fuel cell separator that is adapted to face the membrane electrode assembly, a plurality of first grooves extending in the first direction along the corrugation of the recesses and projections is disposed at intervals from each other in a second direction orthogonal to the first direction, and a second groove extending in the second direction and communicating with the plurality of first grooves is disposed in the bottom portion of each recess.

There is provided an apparatus for manufacturing a thin uneven member. The apparatus includes a lower die fixed to a press bed, an upper die fixed to a ram and disposed opposed to the lower die, and a pressure-drive unit which presses the ram using a servo motor as a power source, the servo motor being fixed to a first support member. The pressure-drive unit includes a motion converting mechanism which converts a rotation of the servo motor to a linear motion of a lifting member, and a cylinder block connected and fixed to the first support member and including first and second pistons arranged in series vertically, wherein the first piston is connected to the lifting member through a second support member, and the second piston, larger in diameter than the first piston, presses the ram.

A fuel cell stack includes a membrane electrode assembly and a bipolar plate. The bipolar plate has a corrugated portion defined by an adjacent pair of proximal and distal peak portions and a sidewall segment connecting the peak portions. The sidewall segment and membrane electrode assembly at least partially define a flow channel. The sidewall segment includes a shoulder portion defining a step spaced away from the peak portions.