Resin frame equipped membrane electrode assembly and method of producing the same
A resin frame equipped membrane electrode assembly includes a membrane electrode assembly and a resin frame member around an outer peripheral portion of the membrane electrode assembly. An inner end of the resin frame member is joined to an electrolyte membrane. In the state before the inner end is joined to the electrolyte membrane, the inner end is narrowed inward in a manner that a surface of the inner end adjacent to the electrolyte membrane gets closer to a surface of the inner end opposite to the electrolyte membrane.
1. A method of producing a resin frame equipped membrane electrode assembly, the resin frame equipped membrane electrode assembly comprising:
a membrane electrode assembly including a first electrode on one surface of an electrolyte membrane, and a second electrode on another surface of the electrolyte membrane; and
a resin frame member provided on and around an outer peripheral portion of the membrane electrode assembly,
the method comprising the steps of:
placing an inner end of the resin frame member between an outer peripheral portion of the first electrode and an outer peripheral portion of the second electrode, the inner end being narrowed inward in a manner that a surface of the inner end adjacent to the electrolyte membrane gets closer to a surface of the inner end opposite to the electrolyte membrane; and
joining the inner end and the electrolyte membrane together, by applying heat and a load to the inner end placed between the outer peripheral portion of the first electrode and the outer peripheral portion of the second electrode;
wherein after the placing step, and before the joining step, a tapered part of the inner end in a narrowed shape is not joined to the electrolyte membrane; and
at time of the joining step, the tapered part is deformed toward the electrolyte membrane, and joined to the electrolyte membrane.
2. The method of producing the resin frame equipped membrane electrode assembly according to claim 1 , wherein in the joining step, the inner end is joined to the electrolyte membrane through an adhesive layer.
3. The method of producing the resin frame equipped membrane electrode assembly according to claim 2 , wherein in the first electrode and the second electrode, a surface size of one electrode is larger than a surface size of another electrode; and
in the joining step, the inner end is joined to the electrolyte membrane which is integral with the other electrode, through the adhesive layer.
4. The method of producing the resin frame equipped membrane electrode assembly according to claim 3 , wherein in a state where the joining step is finished, the one electrode has an inclined area inclined from the electrolyte membrane at a position overlapped with the inner end of the resin frame member; and the other electrode has a flat shape from an area outside the inner end to an area inside the inner end.
5. The method of producing the resin frame equipped membrane electrode assembly according to claim 1 , wherein at the time of the joining step, a surface of the tapered part adjacent to the first electrode is deformed to have an inclined surface inclined inward in a tapered manner to get closer to the electrolyte membrane.
6. The method of producing the resin frame equipped membrane electrode assembly according to claim 5 , wherein at the time of the joining step, an inclined area inclined along the inclined surface is formed at a position of the first electrode overlapped with the inclined surface.