Manufacturing method of cell assembly for fuel cell and manufacturing method of fuel cell

1. A manufacturing method of a cell assembly for a fuel cell, the cell assembly including:

an electrode member having a membrane electrode assembly formed from an electrolyte membrane and a pair of electrode catalyst layers disposed on both sides of the electrolyte membrane in a thickness direction, and a pair of porous layers disposed on both sides of the membrane electrode assembly in the thickness direction;

a separator having an electrode member arrangement portion arranged to be stacked with the electrode member and with which one side of the electrode member in the thickness direction is in contact, and a seal member arrangement portion having a frame shape and disposed on an outer side of the electrode member arrangement portion in a planar direction; and

a seal member formed from a crosslinked item of solid rubber and disposed in the seal member arrangement portion to seal a peripheral edge portion of the electrode member along a shape of the peripheral edge portion and integrate the electrode member and the separator with each other,

the method comprising:

producing the electrode member, the separator, and a seal member preform, which has a frame shape and which is formed from an uncrosslinked item of solid rubber having adhesiveness, in a predetermined shape in advance, as a preliminary production step;

arranging the electrode member, the separator, and the seal member preform in a forming die including a pressing member such that the electrode member is housed in a frame of the seal member preform and such that one side of the electrode member in the thickness direction is in contact with the electrode member arrangement portion, and closing the forming die while the pressing member is pressing the other side of the electrode member in the thickness direction, as a member arrangement step;

moving the pressing member relative to a surface of the forming die in which the pressing member is accommodated; and

pressurizing and heating the forming die to crosslink the uncrosslinked item so that the seal member seals the peripheral edge portion of the electrode member and integrates the electrode member and the separator with each other, as an integration step.

2. The manufacturing method of a cell assembly for a fuel cell according to claim 1 , wherein

the electrode member has a stepped portion that is stepped as viewed in cross section in the thickness direction in at least a part of the peripheral edge portion, and

a die-symmetric stepped portion having a shape that matches the stepped portion is produced on an inner side of the frame of the seal member preform in the preliminary production step.

3. The manufacturing method of a cell assembly for a fuel cell according to claim 1 , wherein the forming die further includes a base die having a concave portion, the method further comprising:

housing the pressing member in the concave portion;

projecting the pressing member from the concave portion;

elastically supporting the pressing member by providing an elastic member interposed between the pressing member and a bottom surface of the concave portion;

pressing, via the pressing member, the other side of the electrode member in the thickness direction utilizing an elastic force of the elastic member during closing of the forming die in the member arrangement step.

4. The manufacturing method of a cell assembly for a fuel cell according to claim 3 , wherein the providing the elastic member interposed between the pressing member and the bottom surface of the concave portion, comprises providing a spring.