JP2016126911A - Fuel battery single cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery single cell in which adhesion strength between a film electrode assembly and a support frame can be enhanced while the uniformity of in-plane pressure of a gas diffusion layer is kept.SOLUTION: A fuel battery single cell 1 has a film electrode assembly 5 in which electrode catalyst layers 5c and 5a are formed at both the sides of an electrolyte membrane 5e respectively, a gas diffusion layer 3c disposed on one side surface of the film electrode assembly so that an outer peripheral edge portion 52e remains, a lower adhesion layer 10 which covers the outer peripheral edge portion and is formed of adhesive agent having an ultraviolet curable property, an upper adhesion layer 11 which is formed of adhesive agent having an ultraviolet curable property on the outer portion of the lower adhesive layer, a support frame 2 disposed on the upper contact layer, and a separator 4 which is fixed to the support frame at a peripheral edge portion thereof and contacts the gas diffusion layer at a center portion thereof. The gas diffusion layer contacts the film electrode assembly at the center portion, and is overlapped with the inner portion of the lower adhesive layer at the outer portion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell single cell.

  A membrane electrode assembly in which electrode catalyst layers are formed on both sides of the electrolyte membrane, a gas diffusion layer disposed so that the outer peripheral edge remains on one side surface of the membrane electrode assembly, and the outer peripheral edge Gas diffusion comprising: an adhesive layer formed of an adhesive having plasticity; a support frame disposed on the adhesive layer; and a separator fixed to the support frame at a peripheral portion and contacting the gas diffusion layer at a central portion. A fuel cell single cell is known in which the layer overlaps with the membrane electrode assembly at the central portion and overlaps with the inner portion of the adhesive layer at the outer portion (see, for example, Patent Document 1).

JP 2014-029834 A

  In the adhesion between the membrane electrode assembly of the single fuel cell and the support frame, it is necessary to increase the thickness of the adhesive layer in order to keep the adhesive strength high. However, in the fuel cell single cell of Patent Document 1, when the thickness of the adhesive layer is increased, the height from the membrane electrode assembly in the outer portion of the gas diffusion layer is equal to the thickness of the adhesive layer. It becomes larger than the height in the central part. In this state, when the separator comes into contact with the top surface of the gas diffusion layer, the in-plane pressure that the outer portion of the gas diffusion layer receives from the separator is higher than the in-plane pressure that the central portion of the gas diffusion layer receives from the separator. Thus, the in-plane pressure uniformity of the gas diffusion layer cannot be maintained. If this happens, a large load in the thickness direction acts on the membrane electrode assembly part under the outer part of the gas diffusion layer, and this membrane electrode assembly part is damaged, or the current is uniform over the entire surface of the membrane electrode assembly. There is a risk that it may become difficult to flow through. A technique capable of maintaining high adhesion strength between the membrane electrode assembly and the support frame while maintaining uniformity of the in-plane pressure of the gas diffusion layer is desired.

  According to the present invention, a membrane electrode assembly in which electrode catalyst layers are formed on both sides of the electrolyte membrane, a gas diffusion layer disposed so that an outer peripheral edge portion remains on one side surface of the membrane electrode assembly, A lower adhesive layer that covers the outer peripheral edge and is formed of an ultraviolet curable adhesive; and an upper adhesive layer that is formed of an ultraviolet curable adhesive on an outer portion of the lower adhesive layer; A support frame disposed on the upper adhesive layer, and a separator fixed to the support frame at a peripheral portion and abutting against the gas diffusion layer at a central portion, wherein the gas diffusion layer includes the gas diffusion layer Is provided with a fuel cell single cell that overlaps with the membrane electrode assembly in the central portion and overlaps with the inner portion of the lower adhesive layer in the outer portion.

  The adhesion strength between the membrane electrode assembly and the support frame can be kept high while maintaining the uniformity of the in-plane pressure of the gas diffusion layer.

It is a fragmentary sectional view which shows the structural example of the fuel cell stack containing a fuel cell single cell. It is the elements on larger scale of FIG. It is a fragmentary sectional view which shows the structural example of the fuel cell stack of a comparative example. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell. It is a fragmentary sectional view which shows the process of the manufacturing method of a fuel cell single cell.

  FIG. 1 is a partial cross-sectional view showing a configuration example of a fuel cell stack A including a single fuel cell 1, and FIG. 2 is a partially enlarged view thereof. As shown in FIG. 1, the fuel cell stack A is formed by a stacked body in which a plurality of fuel cell single cells 1 are stacked in a compressed state in the thickness direction S of the fuel cell single cell 1. The single fuel cell 1 generates electric power by an electrochemical reaction between a fuel gas and an oxidant gas. The electric power generated in the single fuel cell 1 is supplied to the fuel cell via a plurality of wires (not shown) extending from the terminal plates (not shown) arranged at both ends of the laminate to the outside of the fuel cell stack A. It is taken out of the stack A. The electric power taken out from the fuel cell stack A is supplied to, for example, an electric motor for driving an electric vehicle or a capacitor.

  The single fuel cell 1 includes a membrane electrode assembly 5. The membrane electrode assembly 5 includes an electrolyte membrane 5e, and a cathode electrode catalyst layer 5c and an anode electrode catalyst layer 5a formed on both sides of the electrolyte membrane 5e. The electrolyte membrane 5e, the cathode electrode catalyst layer 5c, and the anode electrode catalyst layer 5a have substantially the same size. When the cathode electrode catalyst layer 5c and the anode electrode catalyst layer 5a are arranged on both sides of the electrolyte membrane 5e to form the membrane electrode assembly 5, the electrolyte membrane 5e, the cathode electrode catalyst layer 5c, and the anode electrode catalyst layer 5a substantially overlap each other. . In another embodiment not shown, at least one of the cathode electrode catalyst layer 5c and the anode electrode catalyst layer 5a is smaller than the electrolyte membrane 5e.

  Examples of the material for the electrolyte membrane 5e include a fluorine-based polymer membrane having ion conductivity such as perfluorosulfonic acid. Examples of the material for the cathode electrode catalyst layer 5c and the anode electrode catalyst layer 5a include catalyst-supported carbon that supports a catalyst such as platinum or a platinum alloy. In another embodiment, not shown, an ionomer of the same material as the electrolyte membrane is further added to the catalyst-supporting carbon.

  The gas diffusion layer 3 c is disposed on one side surface 52 of the membrane electrode assembly 5, that is, on the cathode electrode catalyst layer 5 c, whereby the gas diffusion layer 3 c is electrically connected to the membrane electrode assembly 5. Further, the gas diffusion layer 3 a is disposed on the other side surface 51 of the membrane electrode assembly 5, that is, on the anode electrode catalyst layer 5 a, whereby the gas diffusion layer 3 a is electrically connected to the membrane electrode assembly 5. The gas diffusion layer 3 c has a size slightly smaller than that of the membrane electrode assembly 5. When the gas diffusion layer 3c is disposed on the one side surface 52 of the membrane electrode assembly 5, the outer peripheral edge 52e of the one side surface 52 of the membrane electrode assembly 5 remains in a frame shape around the gas diffusion layer 3c. On the other hand, the gas diffusion layer 3 a has substantially the same size as the membrane electrode assembly 5. When the gas diffusion layer 3a is disposed on the other side surface 51 of the membrane electrode assembly 5, the membrane electrode assembly 5 and the gas diffusion layer 3a substantially overlap each other.

  Examples of the material for the gas diffusion layer 3c and the gas diffusion layer 3a include conductive porous bodies, for example, carbon porous bodies such as carbon paper, carbon cloth, and glassy carbon, and metal porous bodies such as metal mesh and foam metal. Is mentioned. Since the gas diffusion layer 3a and the gas diffusion layer 3c are made of the above-described materials, they can be elastically deformed to some extent. In another embodiment, a material having high water repellency such as polytetrafluoroethylene is impregnated to such an extent that the porous body does not lose porosity. In yet another embodiment, a mixed layer of a highly water-repellent material and carbon particles is formed on one side of the porous body.

  A lower adhesive layer 10 is formed on the outer peripheral edge 52e. The lower adhesive layer 10 is formed in the same frame shape as the outer peripheral edge portion 52e, and the thickness thereof is d1. In the embodiment shown in FIG. 2, the lower adhesive layer 10 is formed on the entire surface of the outer peripheral edge 52e so that the outer peripheral edge 52e is not exposed. The lower adhesive layer 10 includes an outer portion 33 positioned on the outer side in the planar direction in the outer peripheral edge portion 52e, an inner portion 31 positioned on the inner side in the planar direction in the outer peripheral edge portion 52e, and the outer portion 33 and the inner portion 31. And an intermediate portion 32 therebetween. The inner portion 31 is interposed between the outer portion 3ce of the gas diffusion layer 3c and the membrane electrode assembly 5, and adheres the outer portion 3ce and the membrane electrode assembly 5. That is, the inner part 31 overlaps the outer part 3ce.

  An upper adhesive layer 11 is formed on the outer portion 33 of the lower adhesive layer 10. The upper adhesive layer 11 is formed in the same frame shape as the outer portion 33 of the lower adhesive layer 10 and has a thickness d2.

  The lower adhesive layer 10 and the upper adhesive layer 11 are formed of an adhesive having ultraviolet (UV) curability that is cured by ultraviolet rays. Examples of the UV curable adhesive include a UV curable adhesive using a radical polymerizable resin and a UV curable resin using a cationic polymerizable resin. In the embodiment shown in FIG. 2, a UV curable adhesive using a radical polymerizable resin is used as the lower adhesive layer 10. In another embodiment not shown, the lower adhesive layer 10 further includes an adhesive having thermosetting properties. In the embodiment shown in FIG. 2, a UV curable adhesive using a cationic polymerizable resin is used as the upper adhesive layer 11.

  The support frame 2 is disposed on the upper adhesive layer 11. The support frame 2 has a frame shape and supports the membrane electrode assembly 5 including the gas diffusion layers 3 c and 3 a on the outer periphery of the membrane electrode assembly 5. The inner portion 21 of the support frame 2 is bonded to the outer peripheral edge 52 e of the membrane electrode assembly 5 by the upper adhesive layer 11 and the lower adhesive layer 10. When the support frame 2 is bonded to the outer peripheral edge 52e, a gap G is formed between the inner end 21g of the support frame 2 and the outer end 3cg of the gas diffusion layer 3c. That is, the support frame 2 is disposed away from the gas diffusion layer 3c.

  The support frame 2 is formed of a material having electrical insulation and airtightness. Examples of the material of the support frame 2 include thermoplastic polypropylene, and further resins such as phenol resin, epoxy resin, polyethylene, and polyethylene terephthalate. The support frame 2 is formed so as to be able to transmit ultraviolet rays (eg, wavelength: 100 to 400 nm) used when the lower adhesive layer 10 and the upper adhesive layer 11 are cured.

  On both sides of the membrane electrode assembly 5 including the gas diffusion layers 3 c and 3 a and the support frame 2, a pair of separators 4 sandwiching them, that is, a cathode separator 4 c and an anode separator 4 a are disposed.

  The peripheral portion 4ce on one side of the cathode separator 4c is fixed to the outer portion 22 on one side of the support frame 2 with the peripheral adhesive layer 13, and the central portion 4cm inside the peripheral portion 4ce is in contact with the gas diffusion layer 3c. Thus, the cathode separator 4c is electrically connected to the gas diffusion layer 3c. In the embodiment shown in FIG. 2, the outer portion 4cme in the plane direction of the central portion 4cm is in contact with the outer portion 3ce. The peripheral adhesive layer 13 seals the cathode electrode side of the fuel cell single cell 1 from the outside. The central portion 4 cm of the cathode separator 4 c is provided with a plurality of grooves for the oxidant gas supply path, and a plurality of oxidants are formed by these grooves, the gas diffusion layer 3 c and the membrane electrode assembly 5 as shown in FIG. A gas supply path 8 is formed. The oxidant gas supplied from the plurality of oxidant gas supply paths 8 is supplied to the membrane electrode assembly 5 through the gas diffusion layer 3c.

  On the other hand, the peripheral portion 4ae on one side of the anode separator 4a is bonded and fixed to the outer portion 22 on the other side of the support frame 2 with the peripheral adhesive layer 12, and the central portion 4am inside the peripheral portion 4ae is the gas diffusion layer 3a. Thus, the anode separator 4a is electrically connected to the gas diffusion layer 3a. In the embodiment shown in FIG. 2, the outer portion 4ame in the planar direction of the central portion 4am is in contact with the outer portion 3ae of the gas diffusion layer 3a facing the outer portion 3ce. The peripheral adhesive layer 12 seals the anode electrode side of the fuel cell single cell 1 from the outside. The central portion 4am of the anode separator 4a is provided with a plurality of grooves for fuel gas supply paths, and a plurality of fuel gas supplies are provided by the grooves, the gas diffusion layer 3a and the membrane electrode assembly 5 as shown in FIG. A path 9 is formed. The fuel gas supplied from the plurality of fuel gas supply paths 9 is supplied to the membrane electrode assembly 5 through the gas diffusion layer 3a.

  In two adjacent fuel cell single cells 1, the cathode separator 4 c of one fuel cell single cell 1 contacts the anode separator 4 a of the other fuel cell single cell 1. As a result, as shown in FIG. 1, a cooling medium supply path 7 sandwiched between two oxidant gas supply paths 8 and two fuel gas supply paths 9 is formed.

  The cathode separator 4c and the anode separator 4a are made of a conductive material that does not transmit an oxidant gas (example: air), a fuel gas (example: hydrogen gas), and a cooling medium (example: water). Examples of the material of the cathode separator 4c and the anode separator 4a include metals such as stainless steel and titanium, and carbon fiber / resin composite materials. The peripheral adhesive layers 12 and 13 are formed of an adhesive having ultraviolet (UV) curability that is cured by ultraviolet rays, particularly an adhesive that can adjust the curing time by changing the amount of UV light. As such an adhesive, a UV curable adhesive using a cationic polymerizable resin is exemplified.

  In the adjacent fuel cell 1, as shown in FIG. 1, the other peripheral edge 4 ae of the anode separator 4 a of one fuel cell 1 and the other side of the cathode separator 4 c of the other fuel cell 1 The peripheral portion 4ce is in contact via the seal member 14. Examples of the material of the seal member 14 include an elastic member such as rubber.

  FIG. 3 shows a comparative example in which the thickness of the adhesive layer 110 is increased in the single fuel cell of Patent Document 1. In order to protect the entire outer peripheral edge 152e of the membrane electrode assembly 105 so as to protect the entire outer peripheral edge 152e, the adhesive layer 110 is provided under the support frame 102 from the outer periphery of the gas diffusion layer 103c. It is formed up to the bottom of the portion 103ce. Further, in order to keep the adhesive strength between the membrane electrode assembly 105 and the support frame 102 high, the thickness of the adhesive layer 110 that bonds the membrane electrode assembly 105 and the support frame 102 is increased. However, in this case, since the thickness D of the adhesive layer 110 is too thick to be absorbed by elastic deformation in the thickness direction of the gas diffusion layer 103c, the height from the one side surface 152 of the outer portion 3ce of the gas diffusion layer 103c is It becomes higher by Δ than the height of the other part of the gas diffusion layer 103c. Then, the in-plane pressure that the outer peripheral edge portion 103ce receives from the separator (not shown) becomes higher than the in-plane pressure that the other portion receives from the separator, and the uniformity of the in-plane pressure of the gas diffusion layer 103c cannot be maintained. . As a result, a large load in the thickness direction acts on a portion below the outer peripheral edge portion 103ce of the membrane electrode assembly 105, the portion is damaged, or a current flows uniformly in the entire surface of the membrane electrode assembly 105. It may be difficult.

  Therefore, in the embodiment shown in FIG. 2, in order to protect the entire outer peripheral edge portion 52e, the lower adhesive layer 10 diffuses gas from below the support frame 2 so that the outer peripheral edge portion 52e can be reliably covered. It is formed under the outer portion 3ce of the layer 3c. At this time, even if the inner portion 31 and the outer portion 3ce of the lower adhesive layer 10 overlap, the thickness d1 of the inner portion 31 is very thin, so the outer portion 3ce is elastically deformed in the thickness direction and the inner portion 31 The thickness d1 can be absorbed. Accordingly, the height h1 from the one side surface 52 of the outer portion 3ce can be set to the same level as the height h2 of another portion, for example, the central portion. As a result, the in-plane pressure that the outer portion 3ce receives from the cathode separator 4c does not become higher than the in-plane pressure that the other portion of the gas diffusion layer 3c receives from the cathode separator 4c. Thereby, the uniformity of the in-plane pressure of the gas diffusion layer 3c can be maintained. Further, the oxidant gas supply path 8 defined by the cathode separator 4c on the gas diffusion layer 3c may be blocked at a raised portion, or may be fluffed at a raised portion of the fiber forming the gas diffusion layer 3c. Absent. On the other hand, the upper adhesive layer 11 and the outer portion 33 of the lower adhesive layer 10 adhere the support frame 2 and the membrane electrode assembly 5. Therefore, the upper adhesive layer 11 and the outer portion 33 can be regarded as an adhesive layer that bonds the support frame 2 and the membrane electrode assembly 5 together. Here, the thickness D of the adhesive layer is the sum (d2 + d1) of the thicknesses of the upper adhesive layer 11 and the outer portion 33. Therefore, by increasing the thickness d2 of the upper adhesive layer 11, the thickness D of the adhesive layer can be increased, and thereby the adhesive strength between the membrane electrode assembly 5 and the support frame 2 can be kept high. From the above, it is possible to increase the thickness D of the adhesive layer that bonds the membrane electrode assembly 5 and the support frame 2 while keeping the thickness d1 of the outer portion 33 thin, and thereby the surface of the gas diffusion layer 3c. The adhesive strength between the membrane electrode assembly 5 and the support frame 2 can be kept high while maintaining the uniformity of the internal pressure.

  Further, the outer portion 33 and the upper adhesive layer 11 may serve as a seal that prevents the cathode electrode side oxidant gas from entering the anode electrode side and the anode electrode side fuel gas from entering the cathode electrode side. It is functioning. In this case, even if the thickness d1 of the outer portion 33 is thin, the distance D between the support frame 2 and the membrane / electrode assembly 5 is adjusted by adjusting the thickness d2 of the upper adhesive layer 11 while maintaining the adhesive strength high. Can be adjusted to a size suitable for. Thereby, the outer portion 33 and the upper adhesive layer 11 can function well as a seal.

  In the comparative example shown in FIG. 3, the adhesive layer 110 is a single layer. In this case, in order to keep the adhesive strength high, that is, to secure the thickness of the adhesive layer, a means of putting beads in the adhesive can be considered. However, the adhesive containing beads is difficult to handle because there is a problem that beads may settle in the container during use and the applied adhesive may cause unevenness of the beads. In addition, putting beads in the adhesive causes a cost increase. In addition, when a beaded adhesive is used, it is not easy to make the inner portion 131 of the adhesive layer 110 below the gas diffusion layer 103c thin.

  However, in the embodiment shown in FIG. 2, the upper adhesive layer 11 is laminated on the lower adhesive layer 10 in order to ensure the thickness of the adhesive layer. Since the thickness of the adhesive layer is secured by the lamination of the upper adhesive layer 11, it is not necessary to put beads in the adhesive. Thereby, it is possible to solve the problem of unevenness and cost that may occur with the adhesive containing beads. Further, the inner portion 31 of the lower adhesive layer 10 can be easily made thin by forming only the lower adhesive layer 10 without using beads.

  In the embodiment shown in FIG. 2, since the lower adhesive layer 10 and the upper adhesive layer 11 use UV-curing adhesive, it is not necessary to set the adhesive at a high temperature for curing. Therefore, in the lower adhesive layer 10, damage or peeling of the lower adhesive layer 10 or the membrane electrode assembly 5 due to a difference in linear expansion coefficient between the lower adhesive layer 10 and the membrane electrode assembly 5 can be suppressed at the time of curing. . Further, the upper adhesive layer 11 can suppress damage or peeling of the upper adhesive layer 11, the support frame 2, or the lower adhesive layer 10 due to the difference in linear expansion coefficient between the upper adhesive layer 11 and the support frame 2 during curing. Moreover, since the upper adhesive layer 11 uses a UV curable adhesive using a cationic polymerizable resin, the curing time can be adjusted by changing the amount of UV light. That is, the curing time can be shortened by increasing the UV light amount, and the curing time can be lengthened by decreasing the UV light amount. Therefore, at the time of manufacturing the fuel cell stack A, the curing time can be adjusted according to the process, and the degree of freedom of the manufacturing process can be increased. For example, by increasing the amount of UV light, the upper adhesive layer 11 can be cured in a short time, and the support frame 2 and the lower adhesive layer 10 can be quickly bonded.

  Further, since the outer peripheral edge 52e of the gap G between the support frame 2 and the gas diffusion layer 3c is protected by the intermediate portion 32 and is not exposed to the outside, the membrane electrode assembly 5 of the outer peripheral edge 52e is deteriorated or the like. You can prevent tearing. In another embodiment (not shown), the support frame 2 and the gas diffusion layer 3c are brought close to each other, and the intermediate portion 32 of the lower adhesive layer 10 is not substantially provided.

  In addition, as the lower adhesive layer 10 and the upper adhesive layer 11, in addition to the UV curable adhesive, a thermoplastic adhesive (eg, adhesive polyethylene) that adheres at a low temperature, or a thermosetting that cures at a low temperature. An adhesive (example: acrylic resin) can also be considered. However, an adhesive having thermoplasticity that adheres at a low temperature decreases the adhesive strength at a high temperature, and therefore cannot be used for a vehicle fuel cell unit cell that requires high-temperature operation. In addition, with thermosetting adhesives that cure at low temperatures, poor handling properties that can not be controlled at room temperature, low productivity due to long curing time, low acid resistance in the case of acrylic resin, etc. Therefore, it is difficult to use the fuel cell unit cell for a vehicle.

  Next, the manufacturing method of a fuel cell single cell is demonstrated. 4 to 14 are partial cross-sectional views showing the respective steps of the method for manufacturing the fuel cell single cell 1.

  First, as shown in FIG. 4, a membrane electrode assembly 5 in which the gas diffusion layer 3a is disposed on the other side surface 51 and the one side surface 52 is exposed is prepared. The gas diffusion layer 3a and the membrane electrode assembly 5 are bonded in advance by being heated and compressed by, for example, a hot press process.

  Next, as shown in FIG. 5, the lower adhesive layer 10 having ultraviolet curability is formed on the outer peripheral edge 52e. The lower adhesive layer 10 is formed of, for example, a UV curable adhesive using a radical polymerizable resin. As a method of forming the lower adhesive layer 10, a method of applying a UV curable adhesive on the outer peripheral edge 52e by screen printing is used. The thickness at the time of application is a thickness at which the thickness becomes approximately d1 after UV curing.

  Subsequently, as shown in FIG. 6, the lower adhesive layer 10 is irradiated with ultraviolet rays UV. As a result, the lower adhesive layer 10 is cured and bonded to the outer peripheral edge portion 52e to protect the outer peripheral edge portion 52e. At this time, the adhesive force (TAC force) remains in the lower adhesive layer 10.

  Next, as shown in FIG. 7, the gas diffusion layer 3 c is disposed on the membrane electrode assembly 5 so that the outer portion 3 ce overlaps the inner portion of the lower adhesive layer 10 in the planar direction. At this time, the outer portion 3ce and the membrane electrode assembly 5 are bonded together by the adhesive force of the inner portion 31. Here, a portion of the lower adhesive layer 10 that overlaps the outer portion 3ce becomes an inner portion 31 of the lower adhesive layer 10. Further, the outer portion of the lower adhesive layer 10 in the planar direction is the outer portion 33, and the intermediate portion 32 is between the inner portion 31 and the outer portion. Further, since the inner portion 31 is thin, the outer portion 3ce does not rise so as to be held by the upper portion of the inner portion 31.

  Subsequently, as shown in FIG. 8, the upper adhesive layer 11 is formed on the inner portion 21 on one side of the support frame 2, and the peripheral adhesive layer 12 is formed on the outer portion 22. The upper adhesive layer 11 and the peripheral adhesive layer 12 are formed of a UV curable adhesive using a cationic polymerizable resin. As a method for forming the upper adhesive layer 11 and the peripheral adhesive layer 12, a method of applying a UV curable adhesive on the inner part 21 and the outer part 22 by screen printing, respectively, is used. The thickness at the time of application is set so that the thickness becomes approximately d2 after the upper adhesive layer 11 is disposed on the outer portion 33 and UV-cured.

  Subsequently, as shown in FIG. 9, the support frame 2 is disposed on the lower adhesive layer 10 so that the upper adhesive layer 11 is in contact with the outer portion 33.

  Subsequently, as shown in FIG. 10, the upper adhesive layer 11 is irradiated with ultraviolet rays UV. Since the support frame 2 is capable of transmitting UV light, the upper adhesive layer 11 is thereby cured and adhered to the inner part 21 on one side and to the outer part 33 on the other side, and thus the support frame. 2 is adhered to the membrane electrode assembly 5. Thereby, the membrane electrode assembly 5, the gas diffusion layer 3c, the gas diffusion layer 3a, and the support frame 2 are integrated. At this time, the peripheral adhesive layer 12 is prevented from being irradiated with ultraviolet rays UV.

  Subsequently, as shown in FIG. 11, the peripheral adhesive layer 13 is formed on the peripheral portion 4ce on one side of the cathode separator 4c. The peripheral adhesive layer 13 is formed of a UV curable adhesive using a cationic polymerizable resin. As a method of forming the peripheral adhesive layer 13, a method of applying a UV curable adhesive on the peripheral part 4ce by screen printing is used.

  Subsequently, as shown in FIG. 12, the peripheral adhesive layer 13 is irradiated with ultraviolet rays UV. At this time, the curing time is delayed by adjusting the UV light amount of the ultraviolet UV so that the peripheral adhesive layer 13 is cured after the cathode separator 4c is disposed on the support frame 2.

  Subsequently, as shown in FIG. 13, the peripheral adhesive layer 12 is irradiated with ultraviolet rays UV. At this time, the curing time is delayed by adjusting the UV light amount of the ultraviolet UV so that the peripheral adhesive layer 12 is cured after the anode separator 4a is disposed on the support frame 2.

  Next, as shown in FIG. 14, the peripheral adhesive layer 13 contacts the outer portion 22 on one side of the support frame 2, and the peripheral portion 4 ae contacts the peripheral adhesive layer 12 on the outer portion 22 on the other side of the support frame 2. In this way, the membrane electrode assembly 5 and the support frame 2 are sandwiched between the pair of cathode separator 4c and anode separator 4a. However, the clamping is finished before the curing time of the peripheral adhesive layers 13 and 12. Thereafter, the peripheral adhesive layers 13 and 12 are cured, so that the membrane electrode assembly 5, the gas diffusion layer 3c, the support frame 2, the cathode separator 4c, and the anode separator 4a are integrated.

  The fuel cell single cell 1 is formed by the above steps.

  In another embodiment (not shown), the peripheral adhesive layer 12 is not formed on the outer portion 22 in the step of FIG. 8, and the peripheral adhesive layer 12 is formed on the outer portion 22 before the ultraviolet ray UV is irradiated in the step of FIG. 13. .

  In still another embodiment (not shown), ultraviolet rays UV are irradiated on the peripheral adhesive layer 12 together with the upper adhesive layer 11 in the step of FIG. 10, and the step of FIG. 13 is omitted. However, the amount of ultraviolet UV irradiated to the peripheral adhesive layer 12 is made smaller than the amount of ultraviolet UV irradiated to the upper adhesive layer 11, and the curing time of the peripheral adhesive layer 12 is delayed.

  In still another embodiment (not shown), the UV adhesive UV is irradiated on the lower adhesive layer 10 together with the upper adhesive layer 11 in the process of FIG. 10, and the process of FIG. 6 is omitted. However, the lower adhesive layer 10 further has thermosetting properties, and in the step of FIG. 7, the gas diffusion layer 3c is bonded to the membrane electrode assembly 5 by hot pressing, and the inner portion 31 of the lower adhesive layer 10 is thermoset. Let

  In yet another embodiment, not shown, at least one of the steps of FIG. 5, FIG. 8, and FIG. 11 uses a dispenser to apply the adhesive.

  In the above embodiment, one side surface 52 (gas diffusion layer 3c side) of the membrane electrode assembly 5 is the cathode electrode side surface, and the other side surface 51 (gas diffusion layer 3a side) is the anode electrode side surface. In another embodiment, one side surface of the membrane electrode assembly 5 is the anode electrode side surface, and the other side surface is the cathode electrode side surface.

DESCRIPTION OF SYMBOLS 1 Fuel cell single cell 2 Support frame 3c Gas diffusion layer 5 Membrane electrode assembly 5a, 5c Electrocatalyst layer 5e Electrolyte membrane 10 Lower adhesive layer 11 Upper adhesive layer 52e Outer peripheral edge

Claims (1)

A membrane electrode assembly in which electrode catalyst layers are respectively formed on both sides of the electrolyte membrane;
A gas diffusion layer disposed so that an outer peripheral edge portion remains on one side surface of the membrane electrode assembly;
A lower adhesive layer covering the outer peripheral edge and formed of an adhesive having ultraviolet curing properties;
On the outer part of the lower adhesive layer, an upper adhesive layer formed of an adhesive having ultraviolet curing properties,
A support frame disposed on the upper adhesive layer;
A separator fixed to the support frame at a peripheral portion and abutting the gas diffusion layer at a central portion;
With
The gas diffusion layer is in contact with the membrane electrode assembly at a central portion and overlaps with an inner portion of the lower adhesive layer at an outer portion.
Fuel cell single cell.

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