Fuel-cell unit cell and manufacturing method therefor

A method of manufacturing a fuel-cell unit cell comprising the steps of:

• (a) preparing a membrane-electrode gas-diffusion-layer assembly (MEGA) plate including an MEGA and a resin frame joined to a periphery of the MEGA, a first separator to be placed in contact with a first surface of the MEGA and also placed on a first-surface side of the resin frame, and a second separator to be placed in contact with a second surface of the MEGA and also placed on a second-surface side of the resin frame;
• and
• (b) stacking the first separator, the MEGA plate, and the second separator to assemble the fuel-cell unit cell,
• wherein
• a gas manifold hole is formed in an outer edge portion of the resin frame,
• a gas-flow-path forming portion with a recessed-and-protruded shape for forming gas flow paths between the gas manifold hole and the first surface of the MEGA is formed on the first surface of the resin frame,
• a thermoplastic bonding portion for surrounding a periphery of the gas manifold hole to cut off gas circulation between the gas manifold hole and the second surface of the MEGA and for bonding the resin frame and the second separator with each other is formed on the second surface of the resin frame so as to pass across a backside of the gas-flow-path forming portion,
• the thermoplastic bonding portion is formed from a first resin and the gas-flow-path forming portion is formed from a second resin higher in melting point than the first resin, and
• the step (b) includes a step of, after the stacking, compressing the gas-flow-path forming portion and the thermoplastic bonding portion of the resin frame from outside of the first separator and the second separator while heating the gas-flow-path forming portions and the thermoplastic bonding portion at a temperature which is not lower than a melting point of the thermoplastic bonding portion and also which is lower than a melting point of the gas-flow-path forming portion so as to fuse the thermoplastic bonding portion to form a fusion-bonding portion bonded to the second separator.