JP6133094B2 - Manufacturing method of fuel cell - Google Patents

Description

  The present invention relates to a fuel cell including a resin frame member surrounding an electrolyte membrane / electrode structure and a method for manufacturing the same.

  The polymer electrolyte fuel cell includes an electrolyte membrane / electrode structure (hereinafter also referred to as MEA) in which an electrolyte membrane made of a polymer ion exchange membrane is sandwiched between an anode electrode and a cathode electrode. As is well known, each of the anode electrode and the cathode electrode has an electrode catalyst layer facing the electrolyte membrane and a gas diffusion layer laminated on the electrode catalyst layer.

  In this type of MEA, one gas diffusion layer of the anode electrode or the cathode electrode is set to have a smaller surface area than the solid polymer electrolyte membrane, and the remaining one gas diffusion layer is set to the same surface area as the electrolyte membrane. In some cases, a so-called step MEA is formed. At that time, the outer wall of the step MEA is surrounded by a resin frame member in order to reduce the amount of use of the relatively expensive electrolyte membrane and to protect the thin membrane and low strength electrolyte membrane.

  A high gas barrier property is required between the resin frame member and the step MEA in order to avoid the occurrence of a cross leak or the like. Therefore, for example, as described in Patent Document 1, the resin frame member and the step MEA are bonded with an adhesive, and are brought into close contact with each other via the adhesive.

JP 2007-66766 A (see paragraph [0065] etc.)

  When the adhesive strength of the adhesive is lowered due to a change with time, it is difficult to keep the resin frame member and the step MEA in close contact with each other, and the gas barrier property is lowered. In order to avoid this, the initial adhesive strength when the adhesive is applied is sufficiently increased. This is because if the initial adhesive strength is large, even if the adhesive strength is reduced to some extent due to the change over time, sufficient adhesive strength that can maintain close contact can be maintained.

  Here, the initial adhesive strength is likely to change under the influence of the coating condition of the adhesive. That is, when the coating conditions change, the initial adhesive strength varies greatly. If many of the initial adhesive strengths are less than the allowable value are manufactured, the yield of the fuel cell will be reduced.

  For these reasons, it is necessary to strictly control conditions such as temperature and humidity during the coating operation. For this reason, a work room or a work chamber in which the temperature and humidity can be kept substantially constant is necessary, and there is a problem that the capital investment increases. Further, such strict management itself complicates the coating work.

The present invention has been made to solve the problems described above, without requiring strict management, moreover, intended to initial adhesive strength is to provide a sufficiently large and a manufacturing method of the variation is small fuel cells And

To achieve the above object, the present invention provides an electrolyte membrane / electrode structure in which an electrolyte membrane made of a solid polymer membrane is interposed between a first electrode and a second electrode, and the electrolyte membrane / electrode structure. In a fuel cell comprising a resin frame member surrounding an outer wall of
The first electrode includes a first electrode catalyst layer facing the electrolyte membrane, a first gas diffusion layer disposed outside the first electrode catalyst layer, and the second electrode includes the first electrode A second electrode catalyst layer facing the electrolyte membrane, and a second gas diffusion layer disposed outside the second electrode catalyst layer,
The second electrode is set to have a smaller area than the electrolyte membrane;
The resin frame member is formed with a recess for accommodating the first electrode and the electrolyte membrane, and an insertion hole into which the second electrode is inserted,
Furthermore, an adhesive layer is provided between the outer edge of the electrolyte membrane protruding from the outer periphery of the second electrode and the inner wall of the recess facing the outer edge,
The surface energy of the inner wall of the recess provided with the adhesive layer is 60 mN / m or more.

  The adhesive layer adheres firmly to the inner wall having such surface energy. That is, peeling hardly occurs between the inner wall of the recess and the adhesive layer. On the other hand, the adhesive layer and the electrolyte membrane are well-familiar, and therefore, peeling between the adhesive layer and the outer edge of the electrolyte membrane hardly occurs.

  For this reason, the initial adhesive strength between the outer edge part of an electrolyte membrane and the inner wall (resin frame member) of a recessed part is large. Therefore, even if the adhesive layer undergoes a change with time, and the adhesive strength is reduced to some extent, sufficient adhesive strength can be maintained.

  Accordingly, the close contact between the step MEA and the resin frame member, and hence the gas barrier property, is maintained, so that it is possible to avoid the occurrence of a cross leak or the like over a long period of time. For this reason, it is also possible to maintain good power generation characteristics of the fuel cell.

The present invention also provides an electrolyte membrane / electrode structure in which an electrolyte membrane made of a solid polymer membrane is interposed between a first electrode and a second electrode, and a resin that surrounds an outer wall of the electrolyte membrane / electrode structure. In a method for manufacturing a fuel cell comprising a frame member,
The first electrode includes a first electrode catalyst layer facing the electrolyte membrane and a first gas diffusion layer disposed outside the first electrode catalyst layer on one end surface of the electrolyte membrane. A manufacturing process;
The second electrode has a second electrode catalyst layer facing the electrolyte membrane on the other end surface of the electrolyte membrane, and a second gas diffusion layer disposed outside the second electrode catalyst layer, And producing a small area compared to the electrolyte membrane;
As the resin frame member, a recess for accommodating the first electrode and the electrolyte membrane and an insertion hole for inserting the second electrode are formed, and an outer periphery of the second electrode in the inner wall of the recess A step of producing a surface energy of 60 mN / m or more of a portion facing the outer edge of the electrolyte membrane protruding from
Bonding the portion of the resin frame member having a surface energy of 60 mN / m or more and the outer edge portion of the electrolyte membrane via an adhesive layer;
It is characterized by having.

  By passing through such a process, an assembly with high initial adhesive strength between the step MEA and the resin frame member can be easily obtained. Moreover, in this case, since the variation in the initial adhesive strength is small, the assembly can be manufactured with a high yield. Therefore, a fuel cell can be obtained efficiently.

  In order to set the surface energy of the inner wall of the concave portion provided with the adhesive layer to 60 mN / m or more, a resin frame member may be manufactured using a material having a surface energy of 60 mN / m or more. However, a resin frame member may be manufactured using a material having a surface energy of less than 60 mN / m, and then the surface energy of the inner wall of the recess may be improved to 60 mN / m or more. In this case, for example, a surface modification process may be performed on the inner wall.

  Examples of this type of surface modification treatment include ozone treatment and ultraviolet treatment, and plasma treatment is particularly preferable. In this case, good adhesive strength is maintained for a relatively long period.

  As another method for improving the surface energy, there is a roughening treatment. More specifically, it is shot peening or polishing. In this case, the inner wall of the recess is roughened more than other parts.

  According to the present invention, in the resin frame member, the surface energy of the inner wall of the recess facing the outer edge of the electrolyte membrane protruding from the outer periphery of the second electrode is set to 60 mN / m or more. For this reason, the electrolyte membrane is firmly bonded to the inner wall via the adhesive layer. That is, the initial adhesive strength is increased.

  Accordingly, even if the adhesive strength of the adhesive layer is lowered to some extent due to changes over time, sufficient adhesive strength is maintained. Therefore, the adhesion between the resin frame member and the MEA is maintained, and as a result, it is possible to avoid the occurrence of cross leak and the like over a long period of time.

  Moreover, the variation in the initial adhesive strength is small. For this reason, the assembly in which the MEA is bonded to the resin frame member can be manufactured with a high yield, so that the fuel cell can be manufactured efficiently.

2 is a schematic longitudinal sectional view of an assembly constituting the fuel cell according to the embodiment of the present invention. It is a chart which shows the relationship between the surface energy of a resin frame member, the average value of peel strength when the electrolyte membrane is detached from the resin frame member, and the variation (standard deviation).

Hereinafter, a manufacturing method of the fuel cells according to the present invention, DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment in relation to a fuel cell obtained by the manufacturing method will be described in detail with reference to the accompanying drawings.

  The fuel cell according to the present embodiment includes an assembly 14 in which an electrolyte membrane / electrode structure (step MEA) 10 shown in FIG. 1 is supported by a resin frame member 12. That is, this assembly 14 is sandwiched between a pair of separators (not shown), thereby forming a unit cell. FIG. 1 is a schematic longitudinal section of the assembly 14.

  The step MEA 10 will be described. The step MEA 10 includes, for example, an electrolyte membrane 16 in which a perfluorosulfonic acid thin film (solid polymer membrane) is impregnated with water, and an anode electrode 18 (first electrode) sandwiching the electrolyte membrane 16. ) And a cathode electrode 20 (second electrode). The electrolyte membrane 16 may be made of a hydrocarbon compound.

  The anode electrode 18 includes a first electrode catalyst layer 22 bonded to one end surface of the electrolyte membrane 16, a first intermediate layer 24 stacked on the first electrode catalyst layer 22, and a first gas diffusion layer 26. . The first electrode catalyst layer 22, the first intermediate layer 24, and the first gas diffusion layer 26 are set to the same outer dimensions as the electrolyte membrane 16. That is, the surface areas of the electrolyte membrane 16, the first electrode catalyst layer 22, the first intermediate layer 24, and the first gas diffusion layer 26 are the same. For this reason, on the anode electrode 18 side, the electrolyte membrane 16 is covered with the anode electrode 18 and there is no exposed portion.

  On the other hand, the cathode electrode 20 includes a second electrode catalyst layer 28 bonded to the other end surface of the electrolyte membrane 16, a second intermediate layer 30 laminated on the second electrode catalyst layer 28, and a second gas diffusion layer 32. Have The second electrode catalyst layer 28, the second intermediate layer 30, and the second gas diffusion layer 32 are set to have the same outer dimension (surface area) and smaller than the outer dimension (surface area) of the electrolyte membrane 16. . For this reason, the outer edge part of the electrolyte membrane 16 protrudes outward from the 2nd electrode catalyst layer 28, the 2nd intermediate | middle layer 30, and the 2nd gas diffusion layer 32 (cathode electrode 20).

  The first electrode catalyst layer 22 and the second electrode catalyst layer 28 are configured, for example, by forming catalyst particles in which platinum particles are supported on carbon black on both end surfaces of the electrolyte membrane 16.

  The 1st intermediate | middle layer 24 and the 2nd intermediate | middle layer 30 are layers for aiming at the balance of the drainage property and water retention of the anode electrode 18 and the cathode electrode 20, for example. In this case, the first intermediate layer 24 and the second intermediate layer 30 are provided as a porous layer containing an electron conductive substance and a water repellent resin.

  In addition, carbons are mentioned as a suitable example of an electron conductive substance. In addition, as a material of the water repellent resin, ETFE (tetrafluoroethylene / ethylene copolymer), PVDF (polyvinylidene fluoride), PVF (polyvinyl fluoride), ECTFE (chlorotrifluoroethylene / ethylene copolymer), PTFE. (Polytetrafluoroethylene), PFA (tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene / hexafluoropropylene copolymer) and other crystalline fluororesins and amorphous fluororesins Examples thereof include silicone resins.

  The 1st gas diffusion layer 26 and the 2nd gas diffusion layer 32 make the base material the carbon paper comprised by containing many fibrous carbon in cellulose, for example. For example, the base material may contain a water-repellent resin made of FEP or the like.

  The resin frame member 12 is disposed so as to surround the outer wall of the step MEA 10 configured as described above. The resin frame member 12 is preferably made of a material having a surface energy of 60 mN / m or more without any surface modification treatment. Examples of such materials include polyvinyl alcohol, melanin resin, hydrophilic resin, and metal material. Moreover, what disperse | distributed the dissimilar material which has hydrophilic property in the resin material may be used.

  The resin frame member 12 does not necessarily need to be made of a material as described above. This is because even a material having a surface energy of less than 60 mN / m can be made 60 mN / m or more by performing a surface modification treatment. In addition, the site | part which should make surface energy 60 mN / m or more, and the surface modification process for improving surface energy are mentioned later.

  Although the surface energy when the surface modification treatment is not performed is less than 60 mN / m, examples of materials that can be suitably used as the material of the resin frame member 12 include PPS (polyphenylene sulfide) and PPA ( Polyphthalamide), PEN (polyethylene naphthalate), PES (polyethersulfone), LCP (liquid crystal polymer), PVDF (polyvinylidene fluoride), silicone rubber, fluoro rubber or EPDM (ethylene propylene rubber) Can do.

  The resin frame member 12 can be produced by, for example, injection molding using a molten resin. Or you may make it produce from a resin film.

  A recess 34 is formed in the resin frame member 12 so as to be recessed from the lower end surface in FIG. 1 toward the upper end surface. Further, an insertion hole 36 is formed to penetrate from the ceiling surface, which is a part of the inner wall of the recess 34, to the upper end surface, which is a part of the outer wall, so as to continue to the recess 34.

  The recess 34 accommodates the entire anode electrode 18 (the first gas diffusion layer 26, the first intermediate layer 24, and the first electrode catalyst layer 22), the electrolyte membrane 16, and the second electrode catalyst layer 28 of the cathode electrode 20. Is done. Accordingly, in the electrolyte membrane 16, the outer edge protruding from the outer periphery of the second electrode catalyst layer 28 faces the ceiling surface (a part of the inner wall) of the recess 34.

  Here, the surface energy of the ceiling surface of the recess 34 is 60 mN / m or more. In addition, what is necessary is just to produce the resin-made frame members 12 from the raw material whose surface energy is 60 mN / m or more in order to make the surface energy of a ceiling surface 60 mN / m or more. Or after producing the resin-made frame member 12 from the raw material whose surface energy is less than 60 mN / m, the surface modification process should just be performed with respect to the ceiling surface of the recessed part 34 at least.

  An adhesive layer 38 is interposed between the protruding outer edge of the electrolyte membrane 16 and the ceiling surface of the recess 34. The adhesive layer 38 is made of various adhesives such as silicone, epoxy, acrylic and urethane. Alternatively, it may be a hot melt adhesive that melts by heating and solidifies by cooling to obtain an adhesive force.

  The adhesive layer 38 (adhesive) adheres firmly to the ceiling surface of the recess 34 whose surface energy is as described above. Accordingly, the initial adhesive strength between the outer edge of the electrolyte membrane 16 and the ceiling surface of the recess 34 (that is, the resin frame member 12) is increased. In addition, there is little variation in initial adhesive strength.

  Further, the second intermediate layer 30 and the second gas diffusion layer 32 of the cathode electrode 20 are inserted into the insertion hole 36. When a gap is formed between the inner wall of the insertion hole 36 and the outer wall of the second intermediate layer 30 and the second gas diffusion layer 32, for example, an adhesive made of a polymer material may be filled.

  The fuel cell according to the present embodiment includes a unit cell in which the assembly 14 configured as described above is sandwiched between a pair of separators. Next, the function and effect of the fuel cell will be described. This will be described in relation to the operation.

  When power is generated from this fuel cell, the reaction gas is supplied to the step MEA 10 through the separator. That is, fuel gas (for example, hydrogen) is supplied to the first gas diffusion layer 26 of the anode electrode 18, and oxidant gas (for example, air) is supplied to the second gas diffusion layer 32 of the cathode electrode 20. When the fuel gas passes through the first intermediate layer 24 and reaches the first electrode catalyst layer 22, a reaction occurs in which hydrogen in the fuel gas is ionized in the first electrode catalyst layer 22. As a result, protons and hydrogen are generated. Protons move to the second electrode catalyst layer 28 by the proton conduction action of the electrolyte membrane 16.

  On the other hand, the oxidant gas passes through the second intermediate layer 30 and reaches the second electrode catalyst layer 28. In the second electrode catalyst layer 28, oxygen in the oxidant gas, protons that have moved to the second electrode catalyst layer 28, and the anode electrode 18 are taken out to energize an external load such as a motor and the cathode electrode. The electrons that have reached 20 react with each other to produce water.

  As described above, during the power generation of the fuel cell, the adhesive strength of the adhesive layer 38 may decrease from the initial adhesive strength due to a change with time.

  However, since the initial adhesive strength of the adhesive layer 38 is large, even if the adhesive strength is reduced to some extent, the step MEA 10 and the resin frame member 12 are in close contact with each other through the adhesive layer 38. For this reason, since the gas barrier property between the step MEA 10 and the resin frame member 12 is maintained, it is possible to avoid the occurrence of a cross leak or the like over a long period of time. Therefore, it is possible to prevent the power generation characteristics of the fuel cell from being deteriorated due to the cross leak.

  As described above, according to the present embodiment in which the surface energy of the ceiling surface of the recess 34 is 60 mN / m or more, it is possible to maintain the close contact between the step MEA 10 and the resin frame member 12 for a long period of time. Therefore, the effect that the favorable power generation characteristic of the fuel cell can be maintained for a long time can be obtained.

  Next, a method for manufacturing the fuel cell according to the present embodiment will be described.

  First, in order to obtain the step MEA 10, an anode electrode 18 is provided on one end surface of the electrolyte membrane 16, and a cathode electrode 20 is provided on the other end surface. For this purpose, first, the first electrode catalyst layer 22 is provided on one end face of the electrolyte membrane 16, and the second electrode catalyst layer 28 is provided on the other end face.

  In order to obtain the first electrode catalyst layer 22, a binder solution is put into a mixture of an electrode catalyst such as platinum and a solvent, and an electrode ink mixed to a predetermined ink viscosity is prepared. Thereafter, this electrode ink is applied to a PET sheet by, for example, screen printing. An electrode ink for providing the second electrode catalyst layer 28 is also prepared in accordance with this, and is applied to a PET sheet different from the PET sheet by screen printing or the like. Note that the amount of the electrode catalyst may be different between the electrode ink to be the first electrode catalyst layer 22 and the electrode ink to be the second electrode catalyst layer 28.

  At this time, the coating area of the electrode ink to be the first electrode catalyst layer 22 is set so that the surface area of the first electrode catalyst layer 22 obtained by dry curing substantially matches the surface area of the electrolyte membrane 16.

  On the other hand, the second electrode catalyst layer 28 has a smaller area than the electrolyte membrane 16 as described above. Therefore, the coating area of the electrode ink to be the second electrode catalyst layer 28 is set such that the surface area of the second electrode catalyst layer 28 obtained by drying and curing is smaller than the surface areas of the first electrode catalyst layer 22 and the electrolyte membrane 16. The

  Next, a PET sheet is attached to each of the one end surface and the other end surface of the electrolyte membrane 16 so that each electrode ink is in contact with the electrolyte membrane 16. In this state, hot pressing is performed to transfer and dry-cure the electrode ink, and then the PET sheet is peeled off. Thereby, the first electrode catalyst layer 22 is provided on one end face of the electrolyte membrane 16 and the second electrode catalyst layer 28 is provided on the other end face.

  Meanwhile, a first superimposed body of the first intermediate layer 24 and the first gas diffusion layer 26 and a second superimposed body of the second intermediate layer 30 and the second gas diffusion layer 32 are produced. That is, for example, a slurry is prepared in which a mixture containing carbon black and PTFE (polytetrafluoroethylene) particles is uniformly dispersed in ethylene glycol. The slurry is applied to each of the two carbon papers and dried, whereby the carbon paper is used as the first gas diffusion layer 26 or the second gas diffusion layer 32, and the slurry is dry-cured. As a result, a second superimposed body that is the first intermediate layer 24 or the second intermediate layer 30 is obtained.

  The two carbon papers are cut so that the surface areas are different from each other. That is, the carbon paper that becomes the first gas diffusion layer 26 is cut out in substantially the same area as the electrolyte membrane 16, while the carbon paper that becomes the second gas diffusion layer 32 is formed by the electrolyte membrane 16 and the first gas diffusion layer 26. Is also cut out in a small area. Since there is such an area difference between the carbon papers, the first intermediate layer 24 inevitably has a larger area than the second intermediate layer 30.

  Next, the first intermediate layer 24 is disposed so as to contact the first electrode catalyst layer 22, and the second intermediate layer 30 is disposed so as to contact the second electrode catalyst layer 28. By performing hot pressing in this state, the first intermediate layer 24 adheres to the first electrode catalyst layer 22 and the second intermediate layer 30 adheres to the second electrode catalyst layer 28. As a result, the step MEA 10 is produced.

  The two types of electrode ink to be the first electrode catalyst layer 22 or the second electrode catalyst layer 28 can be prepared in any order. Similarly, the order of producing the first superimposed body and the second superimposed body is also in random order. Of course, two types of electrode inks may be prepared simultaneously by a plurality of workers, or the first superimposed body and the second superimposed body may be prepared simultaneously.

  On the other hand, the resin frame member 12 in which the recess 34 and the insertion hole 36 are formed is produced. For this purpose, for example, a molten resin made of the above-described material may be used and injection molding may be performed with a mold that forms a cavity having a predetermined shape. Alternatively, the resin frame member 12 may be provided from a resin film.

  When the material itself exhibits a surface energy of 60 mN / m or more, it is not necessary to perform a surface modification treatment. On the other hand, when a material having a surface energy of less than 60 mN / m is used, at least the surface energy of the ceiling surface, which is the portion facing the outer edge of the electrolyte membrane 16 in the inner wall of the recess 34, is improved to 60 mN / m or more. .

  A suitable method for improving the surface energy in this way is a surface modification treatment. Specific examples thereof include plasma treatment, ozone treatment, and ultraviolet (UV) treatment.

  Of these, plasma treatment is particularly preferred. In this case, since the adhesive strength between the ceiling surface of the recess 34 and the adhesive layer 38 is maintained for a long period of time, the outer edge portion of the electrolyte membrane 16 is difficult to peel from the ceiling surface of the recess 34. That is, the adhesion between the resin frame member 12 and the step MEA 10 can be maintained over a long period of time.

  In order to perform the plasma treatment, the ceiling surface of the recess 34 may be irradiated with plasma. The plasma irradiation is continued until the surface energy of the recess 34 is improved to 60 mN / m or more. The irradiation time differs depending on the material.

  Similarly, ozone may be supplied to the ceiling surface of the recess 34 when ozone treatment is performed, and ultraviolet light may be irradiated to the ceiling surface of the recess 34 when UV treatment is performed. Of course, both processes are continued until the surface energy of the recesses is improved to 60 mN / m or more.

  In addition, what is necessary is just to measure surface energy according to the prescription | regulation of JISK6768.

  Next, an adhesive is disposed between the ceiling surface of the recess 34 and the protruding outer edge of the electrolyte membrane 16. Typically, an adhesive is applied to the ceiling surface of the recess 34. In addition, what is necessary is just to arrange | position a hot-melt sheet, when using a hot-melt-adhesive.

  Next, the step MEA 10 is inserted into the recess 34 of the resin frame member 12 from the cathode electrode 20 side. When the outer edge of the electrolyte membrane 16 abuts against the ceiling surface of the recess 34, further entry of the step MEA 10 is prevented. At this time, the anode electrode 18, the electrolyte membrane 16, and the second electrode catalyst layer 28 are accommodated in the recess 34, and the second intermediate layer 30 and the second gas diffusion layer 32 of the cathode electrode 20 are inserted into the insertion hole 36. .

  In this state, the adhesive is cured to form the adhesive layer 38, whereby the stepped MEA 10 and the resin frame member 12 are firmly bonded via the adhesive layer 38 and the assembly 14 in close contact with each other is obtained. .

  As described above, according to the present embodiment, the step MEA 10 and the resin frame member are formed by setting the surface energy of the ceiling surface facing the outer edge of the electrolyte membrane 16 in the inner wall of the recess 34 to 60 mN / m or more. The initial adhesive strength of the adhesive layer 38 for adhering 12 is sufficiently increased. For this reason, when providing the adhesive layer 38, it is not particularly necessary to strictly control the temperature, humidity, and the like.

  Therefore, there is no need to provide a working chamber or working chamber that can keep the temperature and humidity substantially constant. Thereby, capital investment can be reduced.

  In addition, in this case, the variation in the initial adhesive strength is small. For this reason, since the assembly 14 can be manufactured with a high yield, there is an advantage that the fuel cell can be manufactured efficiently.

  The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

  For example, the ceiling surface of the recess 34 may be roughened by performing shot peening or blasting, and thereby the surface energy of the ceiling surface may be improved to 60 mN / m or more.

  In the above embodiment, the anode electrode 18 is a first electrode having a large surface area and the cathode electrode 20 is a second electrode having a small surface area. On the contrary, the cathode electrode 20 has a surface area. The first electrode may be a large first electrode, and the anode electrode 18 may be a second electrode having a small surface area.

  Further, the first intermediate layer 24 and the second intermediate layer 30 may be omitted.

  Furthermore, it goes without saying that only the anode electrode 18 and the electrolyte membrane 16 may be accommodated in the recess 34 and the entire cathode electrode 20 may be inserted into the insertion hole 36.

  Then, the resin frame member 12 may be melted so that part of the meat penetrates into the first gas diffusion layer 26 and the second gas diffusion layer 32.

  First, a step MEA 10 was produced. That is, first, from TGP-H060, which is carbon paper manufactured by Toray, a large slice having an outer dimension of 100 mm × 140 mm and a small slice having a size of 73 × 113 mm were cut out. On the other hand, mixed particles obtained by mixing carbon black and PTFE particles at a weight ratio of 4: 6 were dispersed almost uniformly in ethylene glycol to obtain a slurry. The slurry is applied to each of the large slice and the small slice, dried, and a large-area superimposed body in which the first intermediate layer 24 is laminated on the first gas diffusion layer 26 made of a large slice (carbon paper). A small-area superposed body in which the second intermediate layer 30 was laminated on the second gas diffusion layer 32 made of a small piece (carbon paper) was obtained.

  Further, 1/10 platinum particles of the mixed solvent in a weight ratio were added to a mixed solvent of n-propanol: water = 1: 2 (volume ratio). Thereafter, DE2020 (trade name of perfluorosulfonic acid polymer compound solution manufactured by DuPont), which is an ion conductive polymer solution, was further added at platinum particles: polymer component = 1: 1.5 (weight ratio), and planets were added. Rotational mixing was performed at 80 rpm for 120 minutes with a ball mill. The cathode electrode ink was thus obtained.

Further, this cathode electrode ink was applied on a PET film by screen printing. At this time, the platinum amount was set to 0.5 mg / cm ² . Then, it heated at 60 degreeC for 10 minute (s), then, heated at 100 degreeC under reduced pressure for 15 minutes, and obtained the cathode side electrode catalyst layer (2nd electrode catalyst layer 28).

Meanwhile, an anode side electrode catalyst layer was formed. That is, first, an anode electrode ink was obtained in accordance with the above except that platinum particles: polymer component = 1: 1 (weight ratio). Subsequently, this anode electrode ink was applied by screen printing onto a PET film different from the PET film. At this time, the platinum amount was set to 0.2 mg / cm ² . Then, it heated at 60 degreeC for 10 minute (s), and then, heated at 100 degreeC under reduced pressure for 15 minutes, and obtained the anode side electrode catalyst layer (1st electrode catalyst layer 22).

  Then, the anode-side electrode catalyst layer and the cathode-side electrode catalyst layer are brought into contact with both end surfaces of Nafion NRE-211 (manufactured by DuPont), which is the electrolyte membrane 16, respectively. The anode-side electrode catalyst layer and the cathode-side electrode catalyst layer were bonded to the electrolyte membrane 16 by hot pressing for 8 minutes. Thereafter, the PET film was peeled off.

  Next, the first intermediate layer 24 of the large area superimposed body was brought into contact with the anode side electrode catalyst layer, and the second intermediate layer 30 of the small area superimposed body was brought into contact with the cathode side electrode catalyst layer. In this state, by performing hot pressing for 12 minutes under the conditions of 120 ° C. and 2.0 MPa, large slices (first gas diffusion layer 26), first intermediate layer 24, anodes are formed on both end faces of the electrolyte membrane 16. A large-area anode electrode 18 in which each surface area of the side electrode catalyst layer (first electrode catalyst layer 22) is substantially the same as the surface area of the electrolyte membrane 16, a small section (second gas diffusion layer 32), and a second intermediate layer 30 The cathode-side electrode catalyst layers (second electrode catalyst layers 28) have substantially the same area, and the cathode electrodes 20 each having a smaller area than the electrolyte membrane 16 are formed to obtain a step MEA10. At this time, the outer edge portion of the electrolyte membrane 16 protruded from the outer periphery of the cathode electrode 20.

  Further, the step MEA 10 was trimmed so that the maximum outer dimension was 79.5 mm × 119.5 mm.

  Separately from the above, injection molding is performed using A-900 (PPS) manufactured by Toray Industries, Inc., the outer dimension on the upper end surface side is 100 mm × 140 mm, the opening dimension of the recess 34 is 80 mm × 120 mm, and the opening dimension of the insertion hole 36. A resin frame member 12 having a size of 74 × 114 mm was produced.

  Subsequently, plasma was irradiated to the ceiling surface of the recessed part 34 for a predetermined time using the plasma apparatus YAP-510 made from Yamato Scientific. Thereafter, the surface energy was measured according to JIS K 6768 using a Tenness Checker manufactured by Pacific Chemical.

  Separately from the resin frame member 12 for measurement, a resin frame member 12 made of the same material was produced, and the ceiling surface of the recess 34 was irradiated with plasma under the same conditions. Thereafter, an adhesive made of TB1220G (trade name) manufactured by ThreeBond Co., Ltd. is used between the protruding outer edge of the electrolyte membrane 16 and the ceiling surface of the recess 34 in the resin frame member 12. The width is 3 mm and the thickness is 90 μm. It applied so that it might become. For this application, a dispenser ML-606GX manufactured by Musashi Engineering was used.

  Further, a 5 kg weight is placed on the resin frame member 12 through a PTFE sheet and a flat plate, and held in a drying furnace at 130 ° C. for 120 minutes to cure the TB1220G to form an adhesive layer 38. As a result, an assembly 14 was obtained.

  From this state, the step MEA 10 was cut into a strip shape so that the bonding portion had a width of 2 cm. Further, the large piece (first gas diffusion layer 26) and the first intermediate layer 24, and the small piece (second gas diffusion layer 32) and the second intermediate layer 30 are removed, and the anode is formed with respect to the resin frame member 12. The electrolyte membrane 16 in which the side electrode catalyst layer (first electrode catalyst layer 22) and cathode side electrode catalyst layer (second electrode catalyst layer 28) remained was adhered.

  And the resin-made frame member 12 and the electrolyte membrane 16 in which the electrode catalyst layer remained were each hold | gripped by two holding parts of the autograph AGS-J made from Shimadzu Corporation. Thereafter, the resin frame member 12 and the electrolyte membrane 16 were pulled away from each other to obtain a 180 ° peel strength. This was repeated with 10 samples.

  The relationship between the plasma irradiation time, the surface energy of the ceiling surface of the recess 34 after the plasma irradiation, the average value of the peel strength, and the variation (standard deviation) in the peel strength is shown as a chart in FIG. It can be seen from FIG. 2 that by setting the surface energy of the ceiling surface to 60 mN / m or more, an adhesive portion having excellent peel strength and small variation can be obtained.

  Further, except that Vectra LCP B130 (trade name of liquid crystal polymer) manufactured by Polyplastics was used, the plasma irradiation time, the surface energy of the ceiling surface of the recess 34 after the plasma irradiation, and the peel strength were used. The relationship between the average value and the peel strength variation (standard deviation) was investigated.

  Further, after the resin frame member 12 was prepared using Vectra LCP B130, peel strength measurement was performed in accordance with the above except that the ceiling surface of the concave portion 34 was polished with a # 320 paper file and washed with ethanol. A sample was prepared. For this sample, the relationship between the polishing time, the surface energy of the ceiling surface of the recess 34 after polishing, the average value of peel strength, and the variation (standard deviation) in peel strength was examined.

  Furthermore, a sample for measuring peel strength was prepared in the same manner as described above except that the resin frame member 12 was prepared using a PPS film. Also for this sample, the relationship between the plasma irradiation time, the surface energy of the ceiling surface of the recess 34 after the plasma irradiation, the average value of the peel strength, and the variation (standard deviation) of the peel strength was obtained.

  And after producing the resin-made frame member 12 using Vectra LCP B130, a sample for peel strength measurement was produced based on the above except that a release agent was applied to the ceiling surface of the recess 34. About this sample, the relationship between the surface energy of the ceiling surface of the recessed part 34 after application | coating, the average value of peel strength, and the variation (standard deviation) of peel strength was investigated.

  The above results are also shown in FIG. Similarly to the above, in any case, it is apparent that an adhesive part having excellent peel strength and small variation can be obtained by setting the surface energy of the ceiling surface to 60 mN / m or more.

DESCRIPTION OF SYMBOLS 10 ... Level difference MEA 12 ... Resin frame member 14 ... Assembly 16 ... Electrolyte membrane 18 ... Anode electrode 20 ... Cathode electrode 22 ... 1st electrode catalyst layer 24 ... 1st intermediate | middle layer 26 ... 1st gas diffusion layer 28 ... 2nd Electrode catalyst layer 30 ... second intermediate layer 32 ... second gas diffusion layer 34 ... concave 36 ... insertion hole 38 ... adhesion layer

Claims (3)

An electrolyte membrane / electrode structure in which an electrolyte membrane made of a solid polymer membrane is interposed between a first electrode and a second electrode, and a resin frame member surrounding an outer wall of the electrolyte membrane / electrode structure. In the fuel cell manufacturing method,
The first electrode includes a first electrode catalyst layer facing the electrolyte membrane and a first gas diffusion layer disposed outside the first electrode catalyst layer on one end surface of the electrolyte membrane. A manufacturing process;
The second electrode has a second electrode catalyst layer facing the electrolyte membrane on the other end surface of the electrolyte membrane, and a second gas diffusion layer disposed outside the second electrode catalyst layer, And producing a small area compared to the electrolyte membrane;
As the resin frame member, a recess for accommodating the first electrode and the electrolyte membrane and an insertion hole for inserting the second electrode are formed, and an outer periphery of the second electrode in the inner wall of the recess A step of producing a surface energy of 60 mN / m or more of a portion facing the outer edge of the electrolyte membrane protruding from
Bonding the portion of the resin frame member having a surface energy of 60 mN / m or more and the outer edge portion of the electrolyte membrane via an adhesive layer;
I have a,
Method for manufacturing a fuel cell surface energy of the region is 60 mN / m or more, and the resulting Rukoto by performing surface modification treatment on the inner wall of the recess. 2. The method of manufacturing a fuel cell according to claim 1 , wherein surface modification treatment is performed by plasma irradiation. 2. The method of manufacturing a fuel cell according to claim 1 , wherein the portion having a surface energy of 60 mN / m or more is obtained by roughening an inner wall of the recess.

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