Bonding dies for fuel cell

Bonding dies for producing a fuel cell, the fuel cell including an electrode assembly that includes a membrane electrode assembly having gas diffusion layers stacked on opposite faces of the membrane electrode assembly, and a resin frame fixed on the membrane electrode assembly via a bonded portion of the resin frame, so as to surround an outer periphery of the membrane electrode assembly, the bonding dies being adapted to thermally compress a pair of separators, including a first separator and a second separator, that are arranged on opposite faces of the electrode assembly, thereby bonding the pair of separators to the resin frame, the first separator and the second separator facing and contacting the electrode assembly,

• the bonding dies comprise:
• a first die and a second die, such that when the pair of separators are inserted between the bonding dies the first die faces and contacts the first separator, and the second die faces and contacts the second separator, wherein:
• the first die includes a central receiving portion and an outer periphery receiving portion disposed outside of the central receiving portion, the central receiving portion receiving a central region of the first separator when the pair of separators are inserted between the bonding dies, and the outer periphery receiving portion receiving a peripheral region of the first separator when the pair of separators are inserted between the bonding dies, the peripheral region of the first separator being disposed on an outer periphery of the central region of the first separator,
• the second die includes an inner die and an outer die formed so as to surround the inner die, the inner die pressurizing a central region of the second separator when the pair of separators are inserted between the bonding dies, and the outer die thermally compressing a peripheral region of the second separator when the pair of separators are inserted between the bonding dies, the peripheral region of the second separator being disposed on an outer periphery of the central region of the second separator,
• the inner die of the second die extends from a portion corresponding to the central region of the second separator, along an open edge formed in the resin frame, up to a region closer to an outer periphery side of the electrode assembly than the bonded portion of the resin frame bonded to the membrane electrode assembly when the pair of separators are inserted between the bonding dies, so as to pressurize the resin frame via the second separator,
• there is a clearance formed between the inner die and the outer die of the second die, and
• each of the inner die and the outer die of the second die are independently movable in a direction toward the first die, with respect to each other.