JP5577797B2 - Catalyst layer-electrolyte membrane laminate, membrane-electrode assembly including the same, and polymer electrolyte fuel cell - Google Patents

Description

  The present invention relates to a catalyst layer-electrolyte membrane laminate, and a membrane-electrode assembly and a polymer electrolyte fuel cell including the same.

  A fuel cell is a cell in which electrodes are arranged on both sides of an electrolyte and generates electricity by an electrochemical reaction between hydrogen and oxygen, and only water is generated during power generation. Thus, unlike conventional internal combustion engines, fuel cells are expected to become popular as next-generation clean energy systems because they do not generate environmental load gases such as carbon dioxide. In particular, the polymer electrolyte fuel cell has a low operating temperature and low electrolyte resistance. In addition, it uses a highly active catalyst, so it can achieve high output even with a small size. Is expected to be put to practical use.

  This polymer electrolyte fuel cell uses a solid polymer electrolyte membrane having proton conductivity, and a catalyst layer and a gas diffusion layer are sequentially laminated on both surfaces of the electrolyte membrane. And it has the structure which has arrange | positioned the gasket so that the circumference | surroundings of the electrode which consists of this catalyst layer and a gas diffusion layer may be enclosed, and also this was pinched | interposed with the separator.

  However, as a material of the gasket, for example, as described in Patent Document 1, silicone rubber or the like is used. However, since the operating condition of the fuel cell is high temperature and humidification, gas leaks and battery characteristics Had fallen.

  Therefore, there is a need for a catalyst layer-electrolyte membrane laminate, a membrane-electrode assembly and a polymer electrolyte fuel cell including the catalyst layer-electrolyte membrane laminate that can prevent gas leakage and thereby do not deteriorate battery characteristics.

JP-A-6-96783

  The present invention relates to a catalyst layer-electrolyte membrane laminate that can prevent gas leakage and thereby prevent deterioration of battery characteristics and damage to the electrolyte membrane, and a membrane-electrode assembly and a solid polymer fuel comprising the same. The main problem is to provide a battery.

  The present inventors have intensively studied to solve the above problems. As a result, a catalyst layer-electrolyte membrane laminate in which a catalyst layer is formed on both surfaces excluding the outer peripheral edge of the solid polymer electrolyte membrane, and a frame-like shape adhered to at least one surface of the catalyst layer-electrolyte membrane laminate In a polymer electrolyte fuel cell provided with an edge seal, the edge seal has an adhesive layer and an inorganic thin film layer, so that gas leakage can be prevented, thereby preventing deterioration of battery characteristics. It has been found that an attached catalyst layer-electrolyte membrane laminate, a membrane-electrode assembly with an edge seal and a polymer electrolyte fuel cell having the same can be obtained. The present invention has been completed based on such findings.

The present invention provides a catalyst layer-electrolyte membrane laminate with an edge seal shown in the following items 1 to 11, and a membrane-electrode assembly with an edge seal and a polymer electrolyte fuel cell comprising the same.
Item 1. A catalyst layer-electrolyte membrane laminate in which a catalyst layer is formed on both surfaces excluding the outer peripheral edge of the solid polymer electrolyte membrane; and a frame-shaped edge seal adhered to at least one surface of the catalyst layer-electrolyte membrane laminate; With
The edge seal has an adhesive layer and an inorganic thin film layer ,
The inorganic thin film layer is a chemical vapor deposition film ;
Edge-sealed catalyst layer-electrolyte membrane laminate.
Item 2. Item 2. The catalyst layer-electrolyte membrane laminate with an edge seal according to Item 1, wherein the inorganic thin film layer is an inorganic oxide layer or a metal layer.
Item 3. Item 3. The catalyst layer-electrolyte membrane laminate with an edge seal according to Item 1 or 2, wherein the inorganic thin film layer is a silicon oxide layer.
Item 4. 4. The film according to claim 3, wherein the silicon oxide layer is a film containing silicon oxide and further containing at least one compound composed of at least one element selected from the group consisting of carbon, hydrogen, silicon, and oxygen. Catalyst layer-electrolyte membrane laminate.
Item 5 . Item 5. The catalyst layer-electrolyte membrane laminate with an edge seal according to any one of Items 1 to 4 , wherein the inorganic thin film layer is covered with an insulating film.
Item 6. The edge seal has a hydrogen gas permeability measured by JIS K7126 of 5.0 × 10 ³ cc / m ² · 24 hr · atm or less under the condition of 23 ° C. and 50% RH, and measured by JIS K7129B. Item 6. The catalyst layer-electrolyte membrane laminate with an edge seal according to any one of Items 1 to 5, wherein the water vapor permeability is 10 g / m ² · day or less.
Item 7. The edge seal has a hydrogen gas permeability measured by JIS K7126 of 1.5 × 10 ³ cc / m ² · 24 hr · atm or less under the condition of 23 ° C. and 50% RH, and measured by JIS K7129B. Item 7. The catalyst layer-electrolyte membrane laminate with an edge seal according to any one of Items 1 to 6, wherein the water vapor permeability is 0.2 g / m ² · day or less.
Item 8. On both sides of the catalyst layer-electrolyte membrane laminate, a frame-shaped edge seal having an adhesive layer on the outermost surface and formed slightly larger than the catalyst layer-electrolyte membrane laminate is installed,
Item 8. The catalyst layer-electrolyte membrane laminate with an edge seal according to any one of Items 1 to 7, wherein the outer peripheral edge portions of the edge seal located outside the electrolyte membrane are bonded to each other.
Item 9. The catalyst layer-electrolyte membrane laminate with an edge seal according to any one of Items 1 to 8,
A gas diffusion layer installed on the catalyst layer at the opening of the edge seal of the catalyst layer-electrolyte membrane laminate with the edge seal;
Membrane-electrode assembly with edge seal.
Item 10 . D Jjishiru with catalyst layer - the electrolyte membrane laminate, Rue Jjishiru with film and a gas diffusion layer - an electrode assembly,
The catalyst layer with an edge seal-electrolyte membrane laminate includes a catalyst layer-electrolyte membrane laminate in which a catalyst layer is formed on both surfaces excluding the outer peripheral edge of the solid polymer electrolyte membrane, and the catalyst layer-electrolyte membrane laminate. A frame-shaped edge seal bonded to at least one surface,
The edge seal has an adhesive layer and an inorganic thin film layer,
The gas diffusion layer is disposed on the catalyst layer of the edge seal opening of the catalyst layer-electrolyte membrane laminate with the edge seal and in the opening of the edge seal, and
The edge seal is not placed on the gas diffusion layer,
Membrane-electrode assembly with edge seal.
Item 11. Item 9. The membrane-electrode assembly with an edge seal according to Item 9 or 10 ,
Gaskets respectively installed on the edge seals so as to surround each electrode composed of the catalyst layer and the gas diffusion layer;
A polymer electrolyte fuel cell comprising a separator installed on each of the electrodes and the gasket and having a gas channel formed in a region facing the gas diffusion layer.

  The catalyst layer-electrolyte membrane laminate with an edge seal of the present invention is made to solve the above problems, and is formed on both sides of the solid polymer electrolyte membrane and the outer peripheral edge of the electrolyte membrane. A catalyst layer and a frame-shaped edge seal having an opening in the center, which is adhered to at least one surface of the catalyst layer-electrolyte membrane laminate comprising the electrolyte membrane and the catalyst layer, It has an adhesive layer and an inorganic thin film layer.

  The edge-sealed catalyst layer-electrolyte membrane laminate thus configured is usually used for a polymer electrolyte fuel cell. When used in a polymer electrolyte fuel cell, an electrode composed of a catalyst layer and a gas diffusion layer is formed by forming a gas diffusion layer on the catalyst layer exposed from the opening of the edge seal. Then, a gasket is disposed on the edge seal so as to surround the periphery of the electrode. The polymer electrolyte fuel cell of the present invention has an edge seal having a high gas barrier property, and gas leakage through the edge seal, which has been a problem in the past, can be reduced. As a result, it is possible to prevent a decrease in power generation performance.

The electrolyte membrane-catalyst layer assembly with an edge seal need only have an adhesive layer and an inorganic thin film layer, and can have various configurations. For example, the inorganic thin film layer may be formed directly on the adhesive layer, or the inorganic thin film layer may be formed on the substrate and then laminated with the adhesive layer. As described above, by configuring the edge seal to have the adhesive layer and the inorganic thin film layer, it is possible to reliably prevent gas leakage to the outside. Specifically, in the present invention, the hydrogen gas permeability measured by JIS K7126 is about 5.0 × 10 ³ cc / m ² · 24 hr · atm or less, preferably 4 under the condition of 23 ° C. and humidity of 50% RH. .About.5 × 10 ³ cc / m ² · 24 hr · atm or less (the lower limit is not particularly set, but usually about 1.0 cc / m ² · 24 hr · atm), the water vapor permeability measured by JIS K7129B About 10 g / m ² · day or less, preferably about 5 g / m ² · day or less (the lower limit is not particularly set, but is usually about 1.0 × 10 ⁻² g / m ² · day, and preferably 1. An edge seal of about 0 × 10 ⁻⁶ g / m ² · day) can be formed. Further, the edge seal is not particularly limited, but the hydrogen gas permeability measured according to JIS K7126 is about 3.0 × 10 ³ cc / m ² · 24 hr · atm or less under the condition of 23 ° C. and humidity 0% RH, It is preferably about 2.0 × 10 ³ cc / m ² · 24 hr · atm or less (the lower limit is not particularly set, but is usually about 1.0 cc / m ² · 24 hr · atm).

  The edge seal is formed to be slightly larger than the electrolyte membrane, and it is preferable that the outer peripheral edges located outside the electrolyte membrane are bonded to each other. Conventionally, in order to install the gasket, an electrolyte membrane that is somewhat larger than the electrode is used, and the gasket is installed on the outer peripheral edge of the electrolyte membrane where no electrode is formed. On the other hand, a gasket can be installed on this edge seal by using an edge seal that is slightly larger than the electrolyte membrane. As a result, the electrolyte membrane in which an expensive material is used can be reduced, and the cost can be reduced.

  Further, the membrane-electrode assembly with an edge seal of the present invention is formed on each of the catalyst layers in the opening portion of the edge seal and the catalyst layer-electrolyte membrane assembly with any of the above-described reinforcing sheets. And a gas diffusion layer.

  Further, the polymer electrolyte fuel cell of the present invention is installed on each edge seal so as to surround the periphery of each electrode composed of the membrane-electrode assembly with an edge seal and the catalyst layer and the gas diffusion layer. And a separator installed on each of the electrodes and the gasket.

  In the polymer electrolyte fuel cell of the present invention configured as described above, an edge seal is first disposed on the outer peripheral edge of the electrolyte membrane on which the catalyst layer is not formed. The peripheral edge is constrained, expansion / contraction is suppressed, and as a result, damage to the electrolyte membrane caused by repeated expansion / contraction can be prevented. The gas diffusion layer is formed in the opening of the edge seal, and no edge seal is placed on the gas diffusion layer. Therefore, a flat surface without a step is formed on the gas diffusion layer, and the separator installed on the gas diffusion layer is in uniform contact with the gas diffusion layer, resulting in a problem that the current collection efficiency is lowered. There is no.

  ADVANTAGE OF THE INVENTION According to this invention, a gas leak can be prevented, and thereby a battery layer and an electrolyte membrane laminated body with an edge seal which can prevent a battery characteristic fall and a failure | damage of an electrolyte membrane, and a membrane with an edge seal provided with the same A joined body and a polymer electrolyte fuel cell can be provided.

It is front sectional drawing which shows embodiment of the polymer electrolyte fuel cell of this invention. It is a top view which shows embodiment of the membrane-electrode assembly with an edge seal | sticker of this invention. It is an expanded front sectional view showing an embodiment of a membrane-electrode assembly with an edge seal of the present invention. 5 is a schematic cross-sectional view showing an embodiment of an edge seal having a configuration in which an insulating film 47 is formed on an inorganic thin film layer 43 of an adhesive layer 44 / an inorganic thin film layer 43. FIG. It is explanatory drawing which shows the manufacturing method of the polymer electrolyte fuel cell of this invention. It is explanatory drawing which shows the manufacturing method of the catalyst layer-electrolyte membrane laminated body with an edge seal | sticker of this invention.

  Hereinafter, embodiments of a catalyst layer-electrolyte membrane laminate with edge seal, a membrane-electrode assembly with edge seal, and a polymer electrolyte fuel cell according to the present invention will be described with reference to the drawings.

  FIG. 1 is a front sectional view of a polymer electrolyte fuel cell according to this embodiment, FIG. 2 is a plan view of the polymer electrolyte fuel cell according to this embodiment, and FIG. 3 is a membrane-electrode assembly with an edge seal according to the present invention. It is an expanded front sectional view which shows the detail of the outer periphery part.

  As shown in FIG. 1 and FIG. 2, the solid polymer fuel cell 1 includes a solid polymer electrolyte membrane 2 having a rectangular shape in plan view. A catalyst layer 3 having a rectangular shape in plan view that is slightly smaller than the electrolyte membrane 2 is formed. The solid polymer electrolyte membrane 2 having the catalyst layers 3 formed on both sides thereof is referred to as a catalyst layer-electrolyte membrane laminate 10. Thus, since the catalyst layer 3 is formed slightly smaller than the solid polymer electrolyte membrane 2, the catalyst layer 3 is not formed on the outer peripheral edge 21 of the solid polymer electrolyte membrane 2. In addition, it is preferable that the distance C (refer FIG. 3) from the outer periphery of the solid polymer electrolyte membrane 2 to the outer periphery of the catalyst layer 3 is 0.1-5 mm.

  And the frame-shaped edge seal 4 which has the opening part 41 in the center is adhere | attached on the upper surface and lower surface of this catalyst layer-electrolyte membrane laminated body 10, respectively.

  In a state where the edge seal 4 is adhered to the catalyst layer-electrolyte membrane laminate 10, the catalyst layer 3 is exposed from the opening 41 of the edge seal 4 except for the outer peripheral edge portion 31, and the outside of the catalyst layer 3. The edge seal 4 is provided on the peripheral edge 31 and the outer peripheral edge 21 of the electrolyte 2. In addition, it is preferable that the distance B (refer FIG. 3) from the outer periphery of the catalyst layer 3 to the inner periphery of the edge seal 4 shall be 1-10 mm. In the present embodiment, the edge seal 4 is formed to be slightly larger than the electrolyte membrane 2. In this case, the outer peripheral edge portions 45 of the edge seals 4 protruding from the electrolyte membrane 2 are in contact with each other outside the electrolyte membrane 2. At this time, if the outermost surface of the edge seal 4 on the catalyst layer-electrolyte membrane laminate 10 side is an adhesive layer, the edge seal 4 and the catalyst layer-electrolyte membrane laminate 10 are bonded together, and the edge seals 4 are bonded together. It can also be glued. Here, the distance D (see FIG. 3) from the outer peripheral edge of the edge seal 4 to the outer peripheral edge of the electrolyte membrane 2 is preferably 1 to 100 mm. In addition, the structure in which the edge seal 4 is bonded to the catalyst layer-electrolyte membrane laminate 10 corresponds to the catalyst layer-electrolyte membrane laminate with edge seal of the present invention.

  A gas diffusion layer 5 having a rectangular shape in plan view is formed on the catalyst layer 3 exposed from the opening 41 of the edge seal 4. The distance A (see FIG. 3) from the outer peripheral edge of the gas diffusion layer 5 to the inner peripheral edge of the edge seal 4 is preferably 0 to 5 mm. Thus, the gas diffusion layer 5 is formed on the catalyst layer 3 to constitute the electrode E, and the electrode E formed on both surfaces of the electrolyte membrane 2 is referred to as a membrane-electrode assembly 20. Note that, as in this embodiment, the membrane-electrode assembly 20 provided with the edge seal 4 corresponds to the membrane-electrode assembly with edge seal of the present invention.

  In the polymer electrolyte fuel cell of the present invention, a frame-like gasket 6 is installed so as to surround the electrode E, and a separator 7 is installed on the electrode E and the gasket 6. A gas flow path 71 is formed in the separator 7 in a region facing the gas diffusion layer 5.

  Next, each component of the polymer electrolyte fuel cell 1 of the present invention configured as described above will be described.

<Solid polymer electrolyte membrane 2>
As the solid polymer electrolyte membrane 2, a known or commercially available one can be used. For example, the polymer electrolyte membrane 2 can also be produced by applying a solution containing a hydrogen ion conductive polymer electrolyte on a substrate and drying it. be able to. Examples of the hydrogen ion conductive polymer electrolyte include a perfluorosulfonic acid-based fluorine ion exchange resin, more specifically, a perfluorocarbonsulfonic acid-based resin in which the C—H bond of a hydrocarbon ion-exchange membrane is substituted with fluorine. Examples include polymers (PFS polymers). By introducing a fluorine atom having high electronegativity, it is chemically very stable, the dissociation degree of the sulfonic acid group is high, and high ion conductivity can be realized. Specific examples of such a hydrogen ion conductive polymer electrolyte include “Nafion” (registered trademark) manufactured by DuPont, “Flemion” (registered trademark) manufactured by Asahi Glass Co., Ltd., and “Aciplex” manufactured by Asahi Kasei Corporation. ”(Registered trademark),“ Gore Select ”(registered trademark) manufactured by Gore, and the like. The concentration of the hydrogen ion conductive polymer electrolyte contained in the hydrogen ion conductive polymer electrolyte-containing solution is usually about 5 to 60% by weight, preferably about 20 to 40% by weight. The thickness of the electrolyte membrane is usually about 20 to 250 μm, preferably about 20 to 80 μm.

  Examples of the solid polymer electrolyte membrane 2 include an anion conductive solid polymer electrolyte membrane and a liquid substance-impregnated membrane in addition to the hydrogen ion conductive polymer electrolyte membrane. Examples of the anion conductive solid polymer electrolyte membrane include hydrocarbon resins and fluorine resins. Specific examples of the hydrocarbon-based resin include Aciplex (registered trademark) A201, 211 or 221 manufactured by Asahi Kasei Corporation, Neocepta (registered trademark) AM-1 or AHA manufactured by Tokuyama Corporation, and the like. Examples of the fluororesin include Tosflex (registered trademark) IE-SF34 manufactured by Tosoh Corporation. Moreover, as a liquid substance impregnation film | membrane, polybenzimidazole (PBI) etc. are mentioned, for example.

<Catalyst layer 3>
The catalyst layer 3 is a known or commercially available platinum-containing catalyst layer (cathode catalyst and anode catalyst). Specifically, the catalyst layer 3 contains (1) carbon particles supporting catalyst particles and (2) a hydrogen ion conductive polymer electrolyte.

  Examples of the catalyst particles include platinum, a platinum alloy, a platinum compound, and the like. Examples of platinum alloys include alloys of platinum with at least one metal selected from the group consisting of ruthenium, palladium, nickel, molybdenum, iridium, and iron. In general, the catalyst particles contained in the cathode catalyst layer are platinum, and the catalyst particles contained in the anode catalyst layer are an alloy of the metal and platinum. Moreover, as a hydrogen ion conductive polymer electrolyte, the same material as what is used for the electrolyte membrane mentioned above can be used.

  The carbon particles are not limited as long as they have electrical conductivity, and known or commercially available carbon particles can be widely used. For example, carbon black, graphite, activated carbon or the like can be used alone or in combination. Specific examples of carbon black include channel black, furnace black, ketjen black, acetylene black, lamp black and the like. The arithmetic average particle diameter of the carbon particles is usually about 5 to 200 nm, preferably about 20 to 80 nm. The arithmetic average particle size of the carbon particles can be measured by, for example, a particle size distribution measuring device LA-920: manufactured by Horiba Ltd.

  The film thickness of the catalyst layer 3 is usually about 5 to 200 μm, preferably about 2 to 20 μm.

<Edge seal 4>
The edge seal 4 has an adhesive layer 44 and an inorganic thin film layer 43, and the inorganic thin film layer has a barrier property against water vapor, water, fuel gas, and oxidant gas. The adhesive layer 44 adheres to the catalyst layer-electrolyte membrane laminate 10. The inorganic thin film layer 43 may be formed directly on the adhesive layer 44 or may be formed on the substrate 42 and then laminated with the adhesive layer 44.

Adhesive layer 44
As the resin constituting the adhesive layer 44, for example, polyolefin resins can be preferably used. For example, medium density polyethylene, high density polyethylene, cotton-like low density polyethylene, ethylene-α-olefin copolymer, polypropylene, polybutene, polyisobutene. , Polyisobutylene, polybutadiene, polyisoprene, ethylene-methacrylic acid copolymer, copolymer of ethylene and unsaturated carboxylic acid such as ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ionomer resin, An ethylene-vinyl acetate copolymer or the like can be used. In addition, acid-modified polyolefin resins and silane-modified polyolefin resins obtained by modifying these can also be used. Among these, it is preferable to use polypropylene or polyethylene graft-modified with an unsaturated carboxylic acid in terms of insulation and heat resistance. In addition, it is preferable that the film thickness of the contact bonding layer 44 shall be about 1-500 micrometers, Preferably it is about 15-100 micrometers.

Inorganic thin film layer 43
The inorganic thin film layer 43 may be either an inorganic oxide layer or a metal layer. In addition to inorganic oxides and metals, a layer made of MgF ₂ or the like can also be employed.

  The inorganic oxide used in the inorganic oxide layer is not particularly limited, and examples thereof include silicon oxide, aluminum oxide, titanium oxide, and zirconium oxide. Of these, silicon oxide is preferable because it is inexpensive and has mass productivity.

  The silicon oxide is generally represented by SiOx (0 ≦ x ≦ 2). In the present invention, when a silicon oxide layer is used as the inorganic thin film layer 43, the silicon oxide is substantially silicon oxide. It is preferable that it consists only of. In this case, the silicon oxide layer is a continuous film mainly composed of silicon oxide and containing at least one compound composed of at least one element selected from the group consisting of carbon, hydrogen, silicon and oxygen in addition to silicon oxide. May be. The value of x is not limited, but the average value is preferably 0.8 to 2.0, more preferably 1.0 to 2.0, and still more preferably 1.2 to 2.0. . By setting this range, high gas barrier properties can be obtained. The degree of oxidation (x value) in the silicon oxide thin film can be measured by a photoelectron spectrometer (ESCA) or the like.

  Moreover, it does not restrict | limit especially as a metal used for a metal layer, For example, aluminum, zinc, gold | metal | money, silver, platinum, nickel etc. are mentioned.

  The thickness of the inorganic thin film layer 43 is not limited, but is usually about 2 to 200 nm, preferably about 5 to 50 nm. By setting it as this range, an inorganic thin film layer can be formed uniformly.

  The inorganic thin film layer 43 can be formed by either a dry plating method or a wet plating method. Examples of the dry plating method include physical vapor deposition methods (PVD) such as vacuum deposition, sputtering, and ion plating, and chemical vapor deposition methods (CVD). On the other hand, as the wet plating method, electroless methods are used. Plating is used. Of these, dry plating is preferable, and chemical vapor deposition (CVD) is particularly preferable. Chemical vapor deposition (especially plasma chemical vapor deposition) has advantages such as high density and high gas barrier properties.

  In the present invention, the inorganic thin film layer 43 (particularly when the inorganic thin film layer is a metal layer) may be covered with an insulating film 47 for the purpose of preventing a short circuit. Examples of the material of the insulating coating 47 covered at this time include, for example, an acrylic resin, a styrene resin, a vinyl acetate resin, a polyester resin, a polyethylene resin, a polypropylene resin, a polyamide resin, a phenol resin, an alkyd resin, an epoxy resin, and an organic material. Examples include methyl methacrylate resin, polyacrylate resin, polycarbonate resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, hydroxyethyl cellulose resin, carboxymethyl cellulose resin, polyvinyl chloride resin, melamine resin, polyurethane resin, maleic acid resin, and polyamide resin. Examples of inorganic materials include inorganic oxides such as silicon oxide, aluminum oxide, titanium oxide, and zirconium oxide. In addition, as a method of covering the inorganic thin film layer 43 with the insulating coating 47, for example, in the case of an organic material, a physical solution such as coating a resin solution or bonding a resin film, vacuum deposition of an inorganic oxide material, sputtering, ion plating, etc. Examples thereof include a phase growth method (PVD) and a chemical vapor deposition method (CVD). In addition, when using an inorganic oxide as the inorganic thin film layer 43, it is not necessary to cover with the insulating coating 47 because a short circuit hardly occurs, which is preferable in that the edge seal can be easily manufactured.

Base material 42
As a material of the base material 42, polyester, polyamide, polyimide, polymethyl pentene, polyphenylene oxide, polysulfone, polyether ether ketone, polyphenylene sulfide, cellophane, nylon, or the like can be preferably used. Specific examples of the polyester include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate. In addition, it is preferable that the film thickness of this base material 42 shall be about 5-50 micrometers.

In FIG. 1, for simplicity of explanation, the edge seal 4 in which the base material 42, the inorganic thin film layer 43, and the adhesive layer 44 are laminated in this order is shown. However, the present invention is not limited to this. A wide variety of configurations can be used.

  Specific layer configurations include, for example, adhesive layer 44 / inorganic thin film layer 43, adhesive layer 44 / substrate 42 / inorganic thin film layer 43, adhesive layer 44 / inorganic thin film layer 43 / substrate 42, inorganic thin film layer 43 / Adhesive layer 44 / base material 42, adhesive layer 44 / inorganic thin film layer 43 / base material 42 / inorganic thin film layer 43, inorganic thin film layer 43 / adhesive layer 44 / inorganic thin film layer 43 / base material 42, inorganic thin film layer 43 / adhesion Examples include layer 44 / base material 42 / inorganic thin film layer 43. In addition, when the insulating film 47 is provided, the structure in which the insulating film 47 is provided particularly when the inorganic thin film layer is a metal layer, in addition to the above-described structure, the inorganic thin film so as to eliminate at least the exposed surface of the inorganic thin film layer. The insulating film 47 may be provided on the upper and side surfaces of the layer. For example, as shown in FIG. 4, a metal thin film smaller than the adhesive layer is provided, and an insulating film is provided on the metal film so as to completely cover the metal thin film. Just do it.

<Gas diffusion layer 5>
As the gas diffusion layer 5, various gas diffusion layers constituting a fuel electrode or an air electrode can be used. In order to efficiently supply fuel gas and oxidant gas as fuel to the catalyst layer 3, the gas diffusion layer 5 is porous. It is made of a conductive substrate. Examples of the porous conductive substrate include carbon paper and carbon cloth.

<Gasket 6>
As the gasket 6, it is possible to use a gasket that has a strength sufficient to withstand heat pressing and has a gas barrier property that does not leak out fuel and oxidant to the outside. For example, a polyethylene terephthalate sheet, Teflon ( (Registered trademark) sheet, silicone rubber sheet, and the like.

<Separator 7>
The separator 7 may be any known conductive plate that is known and stable even in the environment within the fuel cell. In general, a carbon plate in which a gas flow path 71 is formed is used. In addition, the separator 7 is made of a metal such as stainless steel, and the surface of the metal is formed with a coating made of a conductive material such as chromium, a platinum group metal or oxide thereof, or a conductive polymer. It is also possible to use a metal having a metal surface plated with a material such as silver, a platinum group composite oxide, or chromium nitride.

  Next, a method for producing the above-described polymer electrolyte fuel cell 1 will be described with reference to the drawings. FIG. 5 is an explanatory view showing a method for producing the polymer electrolyte fuel cell 1 of the present embodiment.

  As shown in FIG. 5, a solid polymer electrolyte membrane 2 made of the above-described material is prepared, and a catalyst transfer film 8 is placed on both surfaces of the solid polymer electrolyte membrane 2.

  Here, the catalyst transfer film 8 is one in which the transferred catalyst layer 3 is formed on the transfer substrate 81.

  The manufacturing method of the catalyst transfer film 8 will be described. First, the above-described carbon particles supporting the catalyst particles and the hydrogen ion conductive polymer electrolyte are mixed and dispersed in an appropriate solvent to prepare a catalyst paste. Then, the catalyst paste is applied onto the transfer substrate 81 through a release layer as necessary in accordance with a known method so that the formed catalyst layer 3 has a desired film thickness. At this time, the catalyst paste is applied to the transfer substrate 81 so that the catalyst layer 3 has a shape slightly smaller than the electrolyte membrane 2. Examples of the coating method of the catalyst paste include known coating methods such as screen printing, spray coating, die coating, and knife coating. Moreover, as said solvent, various alcohols, various ethers, various dialkyl sulfoxides, water, or a mixture thereof etc. are mentioned, Among these, alcohol is preferable. Examples of alcohols include monohydric alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol, isopropanol, n-butanol, and tert-butanol, and various polyhydric alcohols.

  Examples of the transfer base material 81 include polyimide, polyethylene terephthalate, polyparvanic acid aramid, polyamide (nylon), polysulfone, polyethersulfone, polyphenylene sulfide, polyether ether ketone, polyetherimide, polyarylate, and polyethylene naphthalate. And the like. Further, heat resistance of ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroperfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), etc. Fluorine resin can also be used. In addition to the polymer film, the transfer substrate 81 may be coated paper such as art paper, coated paper or lightweight coated paper, or non-coated paper such as notebook paper or copy paper.

  The thickness of the transfer substrate 81 is usually about 6 to 100 μm, preferably about 10 to 30 μm, from the viewpoints of handleability and economy. Therefore, the transfer substrate 81 is preferably a polymer film that is inexpensive and easily available, and more preferably polyethylene terephthalate.

  Then, after applying the catalyst layer forming paste composition, the catalyst layer 3 is formed on the transfer substrate 81 by drying at a predetermined temperature and time. A drying temperature is about 40-100 degreeC normally, Preferably it is about 60-80 degreeC. Although depending on the drying temperature, the drying time is usually about 5 minutes to 2 hours, preferably about 10 minutes to 1 hour.

  Returning to FIG. 5, the description of the method for producing the polymer electrolyte fuel cell will be continued. The catalyst transfer film 8 produced as described above is placed so that the catalyst layer 3 faces the solid polymer electrolyte membrane 2 (FIG. 5 (a)), and the catalyst transfer film 8 is heated and pressed from the back side of the catalyst transfer film 8. The layer 3 is transferred to the solid polymer electrolyte membrane 2, and the transfer substrate 81 of the catalyst transfer film 8 is peeled off (FIG. 5B). In consideration of workability, it is preferable to simultaneously laminate the catalyst layer 3 on both surfaces of the solid polymer electrolyte membrane 2, but the catalyst layer 3 can also be formed on each side.

  The pressure level of the heating press is usually about 0.5 to 20 MPa, preferably about 1 to 10 MPa in order to avoid transfer failure. Further, it is preferable to heat the pressing surface during this pressing operation in order to avoid transfer failure. The heating temperature is usually 200 ° C. or lower, preferably 150 ° C. or lower, in order to avoid damage or deformation of the solid polymer electrolyte membrane 2. Thus, the catalyst layer-electrolyte membrane laminated body 10 is formed by forming the catalyst layer 3 on both surfaces of the solid polymer electrolyte membrane 2. At this time, since the catalyst layer 3 is slightly smaller than the solid polymer electrolyte membrane 2, the outer peripheral edge 21 of the solid polymer electrolyte membrane 2 is exposed.

  Next, the edge seal 4 is attached to the catalyst layer-electrolyte membrane laminate 10 thus formed (FIG. 5C).

  The manufacturing method of the edge seal 4 will be described. First, a sheet-like base material 42 made of the above-described material is prepared. An inorganic thin film layer 43 is formed on the base material 42. As a method of forming the inorganic thin film layer 43 on the base material 42, the method described above can be adopted. Then, the material of the adhesive layer 44 is melted, the above-described material is melted, the material of the adhesive layer 44 is extruded onto the base material 42 by a melt extrusion method, and the adhesive layer 44 is formed into an inorganic thin film. By forming on the layer 43, the edge seal | sticker 4 is produced.

  The edge seal 4 produced as described above is joined to the catalyst layer-electrolyte membrane laminate 10 (FIG. 5C). This process will be described in detail with reference to FIG. The two edge seals 4 made of the above-described materials are overlapped so that the adhesive layers 44 face each other, and the remaining three sides are left bonded to each other. As a result, the two edge seals 4 form a bag body in which an adhesive portion is formed in a U-shape and the left side is open (FIG. 6A). Various known methods can be adopted as the bonding method, such as high frequency welding, hot air welding, hot plate welding, impulse welding, trowel welding, ultrasonic welding, thermosetting bonding, UV curing bonding, etc. Can be adhered by.

  When the bag body is formed by the edge seal 4, an easy-removal region 46 is then formed at the center of each edge seal 4 constituting the bag body (FIG. 6B). The size of the easy removal region 46 is substantially the same as the portion excluding the outer peripheral edge 31 of the catalyst layer 3. The easy-removal region 46 refers to a region that can be easily removed. For example, the easy-removable region 46 can be formed by making a perforation in the outer peripheral edge or making a cut while leaving only a part. Thus, the catalyst layer-electrolyte membrane laminated body 10 is inserted into the bag body in which the easy-removal region 46 is formed from the left side where it is not bonded, and is moved to a predetermined position (FIG. 6C). The predetermined position refers to a position where a portion of the catalyst layer-electrolyte membrane laminate 10 excluding the outer peripheral edge 31 of the catalyst layer 3 faces the easy removal region 46.

  After moving the catalyst layer-electrolyte membrane laminate 10 to a predetermined position, the perforation at the outer peripheral edge of the easy removal region 46 is cut and the easy removal region 46 is removed from each edge seal 4, thereby An opening 41 is formed at the center (FIG. 6D). When the easy removal regions 46 are thus removed from the edge seals 4 and the openings 41 are formed, the catalyst layer 3 of the catalyst layer-electrolyte membrane laminate 10 is removed from the openings 41 except for the outer peripheral edge 31. It will be exposed. In this state, the remaining part of the edge seal 4 that has not been adhered is adhered by a known method, so that the adhesive layer 44 of the edge seal 4 is attached to the outside of the catalyst layer 3 of the catalyst layer-electrolyte membrane laminate 10. While adhering to the peripheral part 31 and the outer peripheral part 21 of the solid polymer electrolyte membrane 2, the edge seals 4 are also adhered to each other. The catalyst layer-electrolyte membrane laminate with edge seal is completed through the above steps (FIGS. 6E and 5C).

  Returning to FIG. 5, the description of the method for producing the polymer electrolyte fuel cell 1 will be continued. On the catalyst layer 3 exposed from the opening 41 of the edge seal 4 described above, the gas diffusion layer 5 is laminated by thermocompression bonding to complete the membrane-electrode assembly with edge seal (FIG. 5D). ). And the gasket 6 is arrange | positioned on the edge seal 4 so that the circumference | surroundings of the electrode E which consists of the catalyst layer 3 and the gas diffusion layer 5 may be enclosed. The separator 7 is disposed on the gas diffusion layer 5 and the gasket 6 so that the gas flow path 71 faces the gas diffusion layer 5 so that the gas diffusion layer 5 and the separator 7 are electrically connected. By sandwiching the membrane-electrode assembly with the separator 7, the polymer electrolyte fuel cell 1 is completed (FIG. 5E).

  As described above, in this embodiment, gas leakage is prevented at the edge seal 4 portion, and as a result, deterioration of battery characteristics can be prevented.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention. For example, in the above-described embodiment, a manufacturing method is employed in which the edge seal 4 is once formed into a bag and the catalyst layer-electrolyte membrane laminate 10 is inserted. However, the present invention is not particularly limited thereto. For example, the edge seals 4 in which the opening portions 41 are formed in advance are arranged on both surfaces of the catalyst layer-electrolyte membrane laminate 10 so that the adhesive layer 44 faces the catalyst layer-electrolyte membrane laminate 10 respectively. The edge seal 4 can be adhered to both surfaces of the catalyst layer-electrolyte membrane laminate 10 by a method or the like to produce a catalyst layer-electrolyte membrane laminate with an edge seal.

  Moreover, in the said embodiment, although the edge seal 4 is comprised from three layers, the base material 42, the inorganic thin film layer 43, and the contact bonding layer 44 for convenience of explanation, you may employ | adopt the other structure mentioned above.

  In the above embodiment, the edge seal 4 is formed to be slightly larger than the catalyst layer-electrolyte membrane laminate 10 and the edge seals 4 are bonded to each other. However, the present invention is not limited to this. 4 may be the same size as the catalyst layer-electrolyte membrane laminate 10.

  Moreover, in the said embodiment, although the surface by the side of the catalyst layer-electrolyte membrane laminated body 10 of the edge seal 4 was used as the contact bonding layer 44, it is not limited to this in particular.

  Further, in the above embodiment, the electrolyte membrane 2, the catalyst layer 3, the gas diffusion layer 5 and the like constituting the solid polymer fuel cell 1 are all described as a rectangular shape in plan view, but the shape is not particularly limited, For example, it can be a circular shape in plan view.

  The present invention will be described more specifically with reference to the following examples and comparative examples. In addition, this invention is not limited to the following Example.

Example 1
As the solid polymer electrolyte membrane 2, NRE212CS (manufactured by Dupont) having a film thickness of 53 μm cut to a size of 63 × 63 mm was used.

Next, the catalyst transfer film 8 was produced in the following manner. First, 2 g of platinum catalyst-supported carbon (platinum supported amount: 45.7 wt%, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd., TEC10E50E), 10 g of 1-butanol, 10 g of 3-butanol, and fluororesin (5 wt% Nafion Binder, manufactured by DuPont) ) 20 g and 6 g of water were added, and these were stirred and mixed in a disperser to prepare a paste composition for forming a catalyst. Next, the paste was applied to a polyester film (X44, thickness 25 μm, manufactured by Toray Industries, Inc.) so that the platinum weight after drying the catalyst layer was 0.4 mg / cm ² , thereby producing a catalyst transfer film 8. did.

  The catalyst transfer film 8 produced as described above was cut into a size of 60 × 60 mm, and placed with the center aligned so that both surfaces of the solid polymer electrolyte membrane 2 faced the solid polymer electrolyte membrane 2 side. Next, the catalyst layer 3 was formed on both surfaces of the solid polymer electrolyte membrane 2 by hot pressing under conditions of 135 ° C., 5.0 MPa, and 150 seconds, and a catalyst layer-electrolyte membrane laminate 10 was produced. The catalyst layer 3 has a thickness of 20 μm.

  Subsequently, an edge seal 4 was produced. Biaxially stretched polyethylene naphthalate (manufactured by Teijin Ltd., Teonex, thickness 12 μm) was used as the base material 42 of the edge seal 4. On this polyethylene naphthalate, a silicon oxide layer 43 (thickness: 10 nm) was formed on one surface of the base material 42 by the plasma CVD method under the following conditions.

Deposition equipment Rewind-type plasma CVD equipment Deposition pressure 3.0 × 10 ⁻² mBar
Introduced gas Hexamethyldisiloxane: Argon: Oxygen = 0.9: 0.9: 3.0 (unit slm)
Applied power AC 40 kHz, 8 kW
Winding speed 150 m / min Degree of vacuum in the vacuum chamber 2-6 × 10 ⁻⁶ mBar
Degree of vacuum in the deposition chamber 2-5 × 10 ⁻³ mBar

Unsaturated carboxylic acid graft-modified polypropylene was extruded at a thickness of 30 μm by melt extrusion to form an adhesive layer 44. With respect to this edge seal 4, the gas permeability of hydrogen was measured according to JIS K7126 and found to be 1.221 × 10 ³ cc / m ² · 24 hr · atm at 23 ° C. and 50% RH under the condition of 23 ° C. and humidity of 0% RH. 4.326 × 10 ³ cc / m ² · 24 hr · atm, and the water vapor permeability measured by JIS K7129B was 2.43 g / m ² · day. The edge seal 4 was cut to a size of 80 × 80 mm, and an opening 41 having a size of 50 × 50 mm was formed at the center. Then, the edge seal 4 is centered on both sides of the catalyst layer-electrolyte membrane laminate 10 and hot pressed under the conditions of 130 ° C., 1.0 MPa, 30 seconds, whereby the edge seal 4 is catalyst layer-electrolyte membrane. Adhering to the laminate 10, a catalyst layer-electrolyte membrane laminate with an edge seal was produced.

  Further subsequently, on the catalyst layer 3 exposed from the opening 41, as a gas diffusion layer 5, carbon paper cut to a size of 49 × 49 mm (manufactured by Toray Industries, Inc., TGP-H-090, thickness) 280 μm) was laminated to form a membrane-electrode assembly 20 with an edge seal.

(Comparative Example 1)
A membrane-electrode assembly 20 with an edge seal was produced by the same material and manufacturing method as in Example 1 except that the edge seal 4 was not installed.

(Evaluation method)
For the membrane-electrode assembly with edge seal of Example 1 and the membrane-electrode assembly of Comparative Example 1, a gasket 6 and a separator 7 were installed to produce a polymer electrolyte fuel cell, and a load fluctuation cycle test was conducted. did. The measurement conditions at this time were a cell temperature of 80 ° C., a fuel utilization rate of 50%, and an oxidant utilization rate of 20%. A result of measuring the leakage current, the leakage current of the fuel cell of Example 1 against the 1 mA / cm ² or less, the leakage current of the fuel cell of Comparative Example 1 is 1.5 mA / cm ² or more, the electrolyte Gas leaks due to film breakage were observed.

  As described above, in the polymer electrolyte fuel cell of Example 1, improvement in gas leakage was observed. Therefore, when a polymer electrolyte fuel cell was produced using the catalyst layer-electrolyte membrane laminate with an edge seal of the present invention. It can be seen that the problem of electrolyte membrane breakage has been solved.

DESCRIPTION OF SYMBOLS 1 Solid polymer fuel cell 2 Solid polymer electrolyte membrane 21 Outer peripheral edge part 3 Catalyst layer 31 Outer peripheral edge part 4 Edge seal 41 Opening part 42 Base material 43 Inorganic thin film layer 44 Adhesive layer 45 Outer peripheral edge part 46 Easy removal area 47 Insulation Coating 5 Gas diffusion layer 6 Gasket 7 Separator 71 Gas flow path 8 Catalyst transfer film 81 Substrate for transfer 10 Catalyst layer-electrolyte membrane laminate 20 Membrane-electrode assembly A From the outer periphery of the gas diffusion layer to the inner periphery of the edge seal B Distance from the outer periphery of the catalyst layer to the inner periphery of the edge seal C Distance from the outer periphery of the solid polymer electrolyte membrane to the outer periphery of the catalyst layer D Distance from the outer periphery of the edge seal to the outer periphery of the electrolyte membrane E electrode

Claims (11)

A catalyst layer-electrolyte membrane laminate in which a catalyst layer is formed on both surfaces excluding the outer peripheral edge of the solid polymer electrolyte membrane; and a frame-shaped edge seal adhered to at least one surface of the catalyst layer-electrolyte membrane laminate; With
The edge seal has an adhesive layer and an inorganic thin film layer ,
The inorganic thin film layer is a chemical vapor deposition film ;
Edge-sealed catalyst layer-electrolyte membrane laminate. The catalyst layer-electrolyte membrane laminate with an edge seal according to claim 1, wherein the inorganic thin film layer is an inorganic oxide layer or a metal layer. The catalyst layer-electrolyte membrane laminate with an edge seal according to claim 1 or 2, wherein the inorganic thin film layer is a silicon oxide layer. 4. The film according to claim 3, wherein the silicon oxide layer is a film containing silicon oxide and further containing at least one compound composed of at least one element selected from the group consisting of carbon, hydrogen, silicon, and oxygen. Catalyst layer-electrolyte membrane laminate. The catalyst layer-electrolyte membrane laminate with an edge seal according to any one of claims 1 to 4 , wherein the inorganic thin film layer is covered with an insulating coating. The edge seal has a hydrogen gas permeability measured by JIS K7126 of 5.0 × 10 ³ cc / m ² · 24 hr · atm or less under the condition of 23 ° C. and 50% RH, and measured by JIS K7129B. 6. The catalyst layer-electrolyte membrane laminate with an edge seal according to claim 1, wherein the water vapor permeability is 10 g / m ² · day or less. The edge seal has a hydrogen gas permeability measured by JIS K7126 of 1.5 × 10 ³ cc / m ² · 24 hr · atm or less under the condition of 23 ° C. and 50% RH, and measured by JIS K7129B. The catalyst layer-electrolyte membrane laminate with an edge seal according to any one of claims 1 to 6, wherein the water vapor permeability is 0.2 g / m ² · day or less. On both sides of the catalyst layer-electrolyte membrane laminate, a frame-shaped edge seal having an adhesive layer on the outermost surface and formed slightly larger than the catalyst layer-electrolyte membrane laminate is installed,
The catalyst layer-electrolyte membrane laminated body with an edge seal in any one of Claims 1-7 to which the outer peripheral edge parts of the edge seal located outside the said electrolyte membrane have adhere | attached. The catalyst layer-electrolyte membrane laminate with an edge seal according to any one of claims 1 to 8,
A gas diffusion layer installed on the catalyst layer at the opening of the edge seal of the catalyst layer-electrolyte membrane laminate with the edge seal;
Membrane-electrode assembly with edge seal. Et Jjishiru with catalyst layer - the electrolyte membrane laminate, Rue Jjishiru with film and a gas diffusion layer - an electrode assembly,
The catalyst layer with an edge seal-electrolyte membrane laminate includes a catalyst layer-electrolyte membrane laminate in which a catalyst layer is formed on both surfaces excluding the outer peripheral edge of the solid polymer electrolyte membrane, and the catalyst layer-electrolyte membrane laminate. A frame-shaped edge seal bonded to at least one surface,
The edge seal has an adhesive layer and an inorganic thin film layer,
The gas diffusion layer is disposed on the catalyst layer of the edge seal opening of the catalyst layer-electrolyte membrane laminate with the edge seal and in the opening of the edge seal, and
The edge seal is not placed on the gas diffusion layer,
Membrane-electrode assembly with edge seal. A membrane-electrode assembly with an edge seal according to claim 9 or 10 ,
Gaskets respectively installed on the edge seals so as to surround each electrode composed of the catalyst layer and the gas diffusion layer;
A polymer electrolyte fuel cell comprising a separator installed on each of the electrodes and the gasket and having a gas channel formed in a region facing the gas diffusion layer.

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