Resin frame equipped membrane electrode assembly and method of producing the same

Abstract

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.

What is claimed is: 
     
         1 . A 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, an inner end of the resin frame member being placed between an outer peripheral portion of the first electrode and an outer peripheral portion of the second electrode and being joined to the electrolyte membrane,   wherein, in a 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.   
     
     
         2 . The resin frame equipped membrane electrode assembly according to  claim 1 , wherein the inner end is joined to the electrolyte membrane through an adhesive layer. 
     
     
         3 . 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
 the inner end is joined to the electrolyte membrane which is integral with the other electrode, through the adhesive layer.   
     
     
         4 . The resin frame equipped membrane electrode assembly according to  claim 3 , wherein 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 resin frame equipped membrane electrode assembly according to  claim 3 , wherein the one electrode includes a catalyst layer on a surface of the one electrode facing the other electrode; and
 an inner peripheral portion of the resin frame member opposite to the electrolyte membrane directly contacts the catalyst layer.   
     
     
         6 . The resin frame equipped membrane electrode assembly according to  claim 3 , wherein the resin frame member includes a first frame shaped sheet, and a second frame shaped sheet joined to the first frame shaped sheet through the adhesive layer; and
 the adhesive layer is provided continuously from a position between the first frame shaped sheet and the second frame shaped sheet to an area overlapped with the electrolyte membrane and the inner end.   
     
     
         7 . The resin frame equipped membrane electrode assembly according to  claim 1 , wherein a tapered part of the inner end in a narrowed shape is positioned inside the outer end of the first electrode and the outer end of the second electrode. 
     
     
         8 . The resin frame equipped membrane electrode assembly according to  claim 1 , wherein in a state where the membrane electrode assembly is formed integrally with a resin frame member, a surface of the inner end adjacent to the first electrode includes an inclined surface inclined in a tapered manner to get closer to the electrolyte membrane; and
 the first electrode includes an inclined area inclined along the inclined surface at a position overlapped with the inclined surface.   
     
     
         9 . The resin frame equipped membrane electrode assembly according to  claim 8 , wherein the outer end of the second electrode is outside the inclined area. 
     
     
         10 . The resin frame equipped membrane electrode assembly according to  claim 8 , wherein the first electrode includes a portion in parallel with the electrolyte membrane, outside the inclined area. 
     
     
         11 . 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.   
     
     
         12 . The method of producing the resin frame equipped membrane electrode assembly according to  claim 11 , wherein in the joining step, the inner end is joined to the electrolyte membrane through an adhesive layer. 
     
     
         13 . The method of producing the resin frame equipped membrane electrode assembly according to  claim 12 , 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.   
     
     
         14 . The method of producing the resin frame equipped membrane electrode assembly according to  claim 13 , 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. 
     
     
         15 . The method of producing the resin frame equipped membrane electrode assembly according to  claim 11 , 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.   
     
     
         16 . The method of producing the resin frame equipped membrane electrode assembly according to  claim 15 , 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. 
     
     
         17 . The method of producing the resin frame equipped membrane electrode assembly according to  claim 16 , 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.