JP5645982B2 - Gas diffusion layer element for polymer electrolyte fuel cell, polymer electrolyte fuel cell and production method thereof - Google Patents

Description

  The present invention relates to a polymer electrolyte fuel cell, and more particularly to improving its gas sealability.

  In a polymer electrolyte fuel cell, one of the polymer electrolyte membranes is exposed to a fuel gas (such as hydrogen) and the other is exposed to an oxidant gas (such as air), and water is synthesized through a chemical reaction via the polymer electrolyte membrane. The basic principle is to electrically extract the reaction energy generated thereby. A schematic diagram showing the structure of a conventional fuel cell is shown in FIG. 1, and a cross section thereof is shown in FIG.

  1 and 2, the reaction gas introduced from the gas flow path formed in the separator 13 causes an electrochemical reaction in the porous catalyst electrode 12 through the polymer electrolyte membrane 11, and the generated electric power is generated in the separator 13. It is collected outside through. As is apparent from this configuration, the polymer electrolyte membrane 11 and the porous catalyst electrode 12 need to be physically joined. In general, porous catalyst electrodes 12 are placed on both sides of the polymer electrolyte membrane 11 and are integrally formed by hot pressing or the like. What was created in this way is called a membrane electrode assembly (MEA) 14 and can be handled independently. The packing 15 is disposed between the membrane electrode assembly 14 and the separator 13 to prevent leakage of introduced gas to the outside.

  The polymer electrolyte membrane has ionic conductivity but does not have air permeability and electronic conductivity, and has a function of physically and electronically separating the fuel electrode and the oxygen electrode. However, when the size of the polymer electrolyte membrane is smaller than the porous catalyst electrode, the porous catalyst electrodes are electrically short-circuited, and the oxidant gas and the fuel gas are mixed to lose the function as a battery. . For this reason, the size of the polymer electrolyte membrane in the surface direction must be the same as or larger than that of the porous catalyst electrode.

  Currently used polymer electrolyte membranes are very thin and do not have physical strength as a structural support. For this reason, it is difficult to take a support structure in which the polymer electrolyte membrane portion protruding from the porous electrode is sandwiched between the packing and the separator. Therefore, as shown in FIG. 2 (A), the size of the porous catalyst electrode 12 is larger than the inner chamber of the separator 13 and smaller than the outer dimension, and the porous catalyst electrode itself is used as a support for the porous catalyst electrode. A way to do this is conceivable. However, since the porous catalyst electrode has good air permeability, in the above configuration, the reaction gas leaks from the end of the porous catalyst electrode to the outside of the separator. Therefore, as shown in FIG. 2 (B), after the porous catalyst electrode is impregnated with a thermosetting resin material, a resin sealing portion 21 is provided by thermosetting this, thereby forming a gas sealing structure. The method of doing is examined (patent document 1).

JP 2001-118592 A JP-A-11-45729 Japanese Patent Laid-Open No. 5-21077 JP 2005-166597 A JP 2004-139828 A

  The following problems can be considered in the above gas sealing structure. In order to dissolve the resin material in a solvent and impregnate the porous electrode to form the resin sealing portion, it is necessary to sufficiently reduce the viscosity of the resin solution. Immediately after the impregnation, the pores in the porous electrode are filled with the resin solution, but the solvent evaporates at the time of curing, and a gap is generated inside the sealed portion after the curing. In addition, the resin material usually undergoes volume shrinkage in the curing reaction. Due to this volume shrinkage and solvent volatilization, gaps remain in the porous electrode, making it difficult to maintain sufficient sealing properties.

  In order to solve this problem, a method of press-fitting an undiluted resin material or a method of mixing a non-shrinkable filler (carbon, talc, etc.) into the resin material has been attempted. However, in such a construction method, it is difficult to fill the pores of the porous electrode with a resin material, and a complete sealing property cannot be obtained.

  In Patent Document 2, an attempt is made to coat a porous electrode with a thermoplastic resin film and perform an adhesive seal with an ion conductive membrane. However, in this method, it is very difficult to sufficiently press the resin into the pores of the porous base material by a hot roll or a hot press, and sealing performance becomes a problem. In addition, since heat and pressure are applied to the entire MEA, wrinkles and distortion occur due to the deformation of the material and the difference in the linear expansion coefficient of the material.

  Patent Document 3 also proposes a method of reinforcing and protecting the electrolyte membrane around the membrane-electrode assembly with a resin film. However, the resin film is formed on the overlapping portion of the porous base material of the resin film and the diffusion layer. There is a risk that a step corresponding to the thickness is generated, and when the layers are stacked and tightened, stress is concentrated there and is damaged.

On the other hand, in order to improve such gas sealing performance, an attempt to apply a sealing material to the outer wall portion of the laminated battery after laminating the required number of fuel cells and fastening the whole has been proposed. When it is desired to replace a unit cell having a lowered level, it is difficult to take out a specific unit cell from such an external seal type.
Therefore, an object of the present invention is to solve these problems.

According to the present invention,
(1) A gas diffusion layer element for a polymer electrolyte fuel cell, comprising: a sheet-like porous substrate; and a sealing resin impregnated in the pores at the peripheral edge of the porous substrate, Solid impregnation characterized in that the sealing resin is impregnated by irradiating the film-shaped sealing resin laminated and disposed on the peripheral portion with laser light to melt the film-shaped sealing resin. A gas diffusion layer element for a molecular fuel cell is provided.

Furthermore, according to the present invention,
(2) The gas diffusion layer element for a polymer electrolyte fuel cell according to (1), wherein the sheet-like porous substrate generates heat by absorbing the energy of the laser beam.

Furthermore, according to the present invention,
(3) The gas diffusion layer element for a polymer electrolyte fuel cell according to (2), wherein the film-form sealing resin is a thermoplastic resin that substantially transmits the laser beam.

Furthermore, according to the present invention,
(4) a step of laminating and arranging a film-like sealing resin on the periphery of the sheet-like porous substrate;
Irradiating the film-form sealing resin with a laser beam to melt the film-form seal resin and impregnating it into the pores of the peripheral portion. A method for producing a gas diffusion layer element for a polymer electrolyte fuel cell comprising a sealing resin impregnated in the pores of a portion is provided.

Furthermore, according to the present invention,
(5) The anode side gas diffusion layer, the membrane electrode assembly, and the cathode side gas diffusion layer are included in order, and the gas diffusion layer on at least one side is any one of (1) to (3) A polymer electrolyte fuel cell comprising a gas diffusion layer element is provided.

Furthermore, according to the present invention,
(6) a step of laminating and arranging a film-like sealing resin on the periphery of the sheet-like porous substrate;
By irradiating the film-form sealing resin with laser light, the film-form seal resin is melted and impregnated in the pores of the peripheral portion, and the pores in the peripheral portion of the porous base material are impregnated. Obtaining a gas diffusion layer element comprising an impregnated sealing resin;
There is provided a method for producing a polymer electrolyte fuel cell comprising the step of using the gas diffusion layer element as a gas diffusion layer on at least one side and combining the membrane electrode assembly and the gas diffusion layer on the opposite side in this order. The

Furthermore, according to the present invention,
(7) In order, combining the anode side gas diffusion layer, the membrane electrode assembly, and the cathode side gas diffusion layer,
A step of laminating and arranging a film-like sealing resin on the periphery of the gas diffusion layer on at least one side;
Manufacturing the polymer electrolyte fuel cell comprising a step of irradiating the film-form sealing resin with a laser beam to melt the film-form seal resin and impregnating the resin in the peripheral edge A method is provided.

Furthermore, according to the present invention,
(8) a step of laminating and arranging a film-like sealing resin on the periphery of the gas diffusion layer on the opposite side;
A process for melting the film-like sealing resin by irradiating the film-like sealing resin with a laser beam and impregnating the film-like sealing resin in the pores of the peripheral portion. Provided.

  According to the present invention, the peripheral portion of the gas diffusion layer element for the polymer electrolyte fuel cell is sealed by melting and impregnating the sealing resin by laser light irradiation, so that the reaction gas is discharged from the end of the gas diffusion layer. Leakage outside the separator is prevented. In addition, since heat is applied only to the sealing portion by laser light irradiation, the occurrence of wrinkles and distortion due to the deformation of the material and the difference in the linear expansion coefficient of the material is prevented. In addition, since there is no level difference corresponding to the thickness of the sealing resin film at the overlapping portion of the sealing resin film and the gas diffusion layer, there is a risk that stress will be concentrated and damaged when the MEAs are stacked and tightened. Disappear. Furthermore, when it is desired to replace a unit battery whose output has decreased during driving, it is easy to take out a specific unit battery.

It is a substantially exploded perspective view showing the structure of a conventional fuel cell. It is the substantially cross-sectional view which showed the basic structure of the conventional fuel cell. FIG. 3 is a schematic cross-sectional view showing a method for producing a gas diffusion layer element according to the present invention. 1 is a schematic exploded cross-sectional view showing a method for producing a polymer electrolyte fuel cell according to the present invention. FIG. 6 is a schematic cross-sectional view showing a method for producing a polymer electrolyte fuel cell according to another embodiment of the present invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. A gas diffusion layer element for a polymer electrolyte fuel cell according to the present invention comprises a sheet-like porous base material and a sealing resin impregnated in pores at the peripheral edge of the porous base material. The resin for sealing is impregnated by irradiating the resin for film sealing laminated on the peripheral edge with a laser beam to melt the resin for sealing film. FIG. 3 shows a basic aspect of the present invention. According to the present invention, as shown in FIG. 3A, first, a film-like sealing resin 200 is laminated and disposed on the peripheral edge of the sheet-like porous substrate 120. Next, the film-form sealing resin 200 is irradiated with a laser beam to melt the film-form seal resin 200 and impregnate the pores in the peripheral portion, as shown in FIG. Then, the gas diffusion layer element 100 including the sealing portion 210 in which the sealing resin is impregnated in the pores at the peripheral portion of the porous base material is obtained.

  As the sheet-like porous substrate 120, a sheet-like material having air permeability and conductivity suitable for a polymer electrolyte fuel cell is used. In particular, since heat can be generated by absorbing the energy of the irradiation laser light, a carbon breathable conductive material such as carbon paper, carbon woven fabric, carbon non-woven fabric, or carbon felt is used as the sheet-like porous substrate 120. It is preferable to use it. The thickness of the sheet-like porous substrate 120 may be appropriately adjusted according to the design of the fuel cell, and is generally used in the range of 100 to 500 μm, preferably 200 to 400 μm.

  In order to remove the humidified water supplied together with the fuel gas and the oxidant gas and the water generated by the reaction of the fuel cell, the sheet-like porous substrate 120 is repelled at least at the part in contact with the membrane electrode assembly (MEA). It is preferable to perform water treatment. As such a water repellent treatment method, a method known in the art can be used. For example, if necessary, a dispersion of a fluororesin such as polytetrafluoroethylene (PTFE) is made into a sheet-like porous material. The substrate may be partially impregnated. Further, a protective layer is provided on the contact surface of the sheet-like porous substrate 120 with or without the water-repellent treatment with the MEA to improve the electrical contact with the MEA. Damage due to the substrate can also be reduced. Such a protective layer may be formed, for example, by applying a dispersion (paste) of a mixture of a fluororesin such as PTFE and carbon black, drying, and heat-treating. When providing a protective layer, it is preferable that the thickness exists in the range of 5-20 micrometers in balance with gas diffusibility and electroconductivity. For details of the water repellent treatment and the protective layer, refer to JP-A-10-261421 by the same applicant.

  As the film-form sealing resin 200, a thermoplastic resin that can be melted by heat and impregnated in the pores of the porous substrate may be used. In the present invention, the film-form sealing resin 200 is melted by laser light irradiation. However, even when the sealing resin itself melts by absorbing the laser light and generating heat, the sealing resin does not emit the laser light. The case where the porous substrate 120 absorbs the laser beam and generates heat and the resin is melted by being transmitted to the sealing resin is also included in the present invention. However, in the present invention, only the interface between the porous base material and the sealing resin is heated so that the sealing resin is well impregnated into the porous base material, and other portions of the sealing resin are In view of being hardly affected by heat, it is preferable to use a thermoplastic resin that substantially transmits laser light. A thermoplastic resin that substantially transmits laser light refers to a transparent or translucent thermoplastic resin that transmits laser light, which itself absorbs the energy of laser light and converts it into heat. It is a difficult thermoplastic resin. Examples of such thermoplastic resins include polycarbonate resins, polyolefin resins, polystyrene resins, polyvinyl chloride resins, polyvinylidene chloride resins, polyacryl resins, polyacrylamide resins, polydiene resins, polyamide resins. Examples thereof include resins and polyester resins. The thickness of the film-form sealing resin 200 is generally in the range of 10 to 200 μm, preferably 30 to 150 μm. Further, the thickness of the film-like sealing resin 200 is preferably thinner than the above-mentioned sheet-like porous substrate 120, and particularly within the range of 10 to 80% of the thickness of the sheet-like porous substrate 120. It is preferable. If the thickness of the film-like sealing resin 200 is less than 10% of the thickness of the sheet-like porous substrate 120, sealing of the porous substrate becomes insufficient, and the reaction gas is at the end of the gas diffusion layer. May leak out of the separator. On the other hand, if the thickness of the film-like sealing resin 200 is greater than 80% of the thickness of the sheet-like porous base material 120, the sealing resin becomes excessive and a step is generated in the sealing portion, which is not desirable.

  According to the present invention, as shown in FIG. 3 (A), a film-like sealing resin 200 is laminated on the periphery of the sheet-like porous substrate 120, and then laser light is applied to the film-like sealing resin 200. Irradiate. The sealing resin in the portion irradiated with the laser light is melted and impregnated into the sheet-like porous substrate 120, and the irradiation of the laser light stops (for example, the scanned laser light passes), so that the impregnating resin becomes It cools and solidifies and forms the sealing part 210 as shown in FIG.3 (B). It is difficult to control the degree of resin impregnation or encapsulation in the conventional resin solution impregnation or hot-pressure encapsulation of molten resin for forming the resin sealing portion on the porous substrate. When a laser is used, the resin part that is melted by heat is extremely limited, and the melting of the resin can be precisely controlled according to the laser irradiation conditions (intensity, irradiation time, scanning speed, etc.), and thus the impregnation of the resin is controlled. It becomes easy. Further, in order to melt and impregnate a porous base material with a heat-resistant material having a high glass transition point, a high temperature of 200 ° C. or higher is generally required. In that case, when the film-like resin is hot-pressed at a high temperature, the film-like resin may shrink and deform when it is returned to room temperature. Melt impregnation can be performed without the occurrence of. In addition, engineering plastics, which have higher melting points and glass transition points than electrolyte membranes and are superior in durability, heat resistance, and other performances, are used as sealing resins, and porous substrates are impregnated with conventional methods such as hot pressing. In this case, it is necessary to heat the electrolyte membrane at a temperature higher than the heat-resistant temperature, which is substantially difficult to implement. However, when a laser is used, only the laser-irradiated portion is heated, and the electrolyte membrane and other portions are not adversely affected by heat, and therefore engineering plastics can also be used.

Lasers usable for laser light irradiation according to the present invention include semiconductor lasers, gas (He—Ne, Ar ⁺ , CO ₂ ) lasers, solid (ruby, glass) lasers, liquid (organic, dye) lasers, YAG lasers, and the like. Is mentioned. The laser is well known as one used in general-purpose laser resin welding machines. Regarding the conditions for laser light irradiation, those skilled in the art can appropriately set the conditions according to the specific porous substrate and sealing resin to be used. As an example, a CO ₂ laser (wavelength 940 nm) is used. Irradiation is performed at an output of 3 to 15 W, a laser spot diameter of 1.5 to 2.7 mm, and a scanning speed of 3 to 10 mm / sec.

When irradiating the film-form sealing resin 200 with laser light according to the present invention, the sealing resin 200 is pressed against the porous base material 120 in order to promote the impregnation of the sheet-like porous base material 120. It is preferable to apply. For pressing, a sheet-like porous substrate 120 is placed on a suitable base (not shown), a film-like sealing resin 200 is laminated thereon, and a laser beam such as a glass plate is further transmitted thereon. The substrate can be mounted by applying a pressure of up to about 9.8 × 10 ⁵ Pa (10 kgf / cm ² ) between the base and the substrate with an appropriate fastening jig. Since the sealing resin heated and melted by laser light irradiation is pressed against the porous substrate, the impregnation of the porous substrate into the pores is promoted.

FIG. 4 is a schematic exploded view of a preferred polymer electrolyte fuel cell according to the present invention in which the gas diffusion layer element 100 according to the present invention is combined on both sides of the membrane electrode assembly 300. The polymer electrolyte membrane 310 used for the membrane electrode assembly 300 is not particularly limited as long as it has high proton (H ⁺ ) conductivity, is electronically insulating, and is gas impermeable. Any known polymer electrolyte membrane may be used. A typical example is a resin having a fluorine-containing polymer as a skeleton and a group such as a sulfonic acid group, a carboxyl group, a phosphoric acid group, or a phosphonic group. Since the thickness of the polymer electrolyte membrane 310 greatly affects the resistance, a thinner one is required as long as the electronic insulation and gas impermeability are not impaired. Specifically, the thickness is 5 to 50 μm, preferably 10 It is set within a range of ˜30 μm. Typical examples of the polymer electrolyte membrane 310 include Nafion (registered trademark) membrane (manufactured by DuPont) and Flemion (registered trademark) membrane (manufactured by Asahi Glass Co., Ltd.), which are perfluoropolymers having a sulfonic acid group in the side chain. . Also, GORE-SELECT (registered trademark) (manufactured by Japan Gore-Tex), which is a reinforced polymer electrolyte membrane in which an expanded porous polytetrafluoroethylene membrane is impregnated with an ion exchange resin, can be suitably used.

The catalyst layer 320 is not particularly limited as long as it contains catalyst particles and an ion exchange resin, and conventionally known ones can be used. The catalyst is usually made of a conductive material carrying catalyst particles. The catalyst particles may be any catalyst particles that have a catalytic action in the oxidation reaction of hydrogen or the reduction reaction of oxygen. In addition to platinum (Pt) and other noble metals, iron, chromium, nickel, and alloys thereof may be used. it can. As the conductive material, carbon-based particles such as carbon black, activated carbon, graphite and the like are suitable, and fine powder particles are particularly preferably used. Typically, carbon black particles having a surface area of 20 m ² / g or more carry noble metal particles such as Pt particles or alloy particles of Pt and other metals. In particular, for anode catalysts, Pt is vulnerable to carbon monoxide (CO) poisoning. Therefore, when a fuel containing CO such as methanol is used, alloy particles of Pt and ruthenium (Ru) are used. It is preferable. The ion exchange resin in the catalyst layer 320 is a material that supports the catalyst and serves as a binder for forming the catalyst layer, and has a role of forming a passage for ions and the like generated by the catalyst to move. As such an ion exchange resin, those similar to those described above in relation to the polymer electrolyte membrane 310 can be used. The catalyst layer 320 is preferably porous so that a fuel gas such as hydrogen and methanol can contact the catalyst as much as possible at the anode and an oxidant gas such as oxygen and air can contact the catalyst as much as possible. Further, the amount of catalyst contained in the catalyst layer 320, 0.01 to 1 mg / cm ^2, preferably suitably be in the range of 0.1-0.5 mg / cm ^2.

  As a method of joining the catalyst layer 320 to the polymer electrolyte membrane 310 to form the membrane electrode assembly 300, as long as dense joining with low contact resistance is achieved without damaging the polymer electrolyte membrane 310, conventional methods are possible. Any known method can be employed. For example, the catalyst layer 320 can be bonded to the polymer electrolyte membrane 310 by a conventionally known method such as a screen printing method, a spray coating method, or a decal method.

  By combining the gas diffusion layer 100 according to the present invention on at least one side of the membrane electrode assembly 300 obtained by combining the catalyst layer 320 with the polymer electrolyte membrane 310 as described above, the solid polymer fuel according to the present invention is obtained. A battery can be formed. At that time, as shown in FIG. 4, an adhesive 250 may be disposed on one side of the gas diffusion layer 100 and integrated by hot pressing. As the adhesive 250, an adhesive sheet such as a printed wiring board adhesive sheet may be used. What is necessary is just to set the conditions of hot press so that the polymer electrolyte membrane 310 may not be impaired especially according to the adhesion conditions of the adhesive agent 250 to be used.

  The order of integration of the polymer electrolyte fuel cells may be an order in which the catalyst layer 320 and the gas diffusion layer 100 are first combined to form an anode electrode or a cathode electrode, and these are joined to the polymer electrolyte membrane 310. . For example, a catalyst layer forming coating solution containing catalyst particles and an ion exchange resin is prepared using an appropriate solvent, and this is applied to the gas diffusion layer 100 according to the present invention to form the catalyst layer 320. It can also be joined to the polymer electrolyte membrane 310.

  FIG. 5 is a schematic cross-sectional view for explaining a method for producing a polymer electrolyte fuel cell according to another embodiment of the present invention. In this embodiment, as shown in FIG. 5A, first, after combining the respective sheet-like porous substrates 120 on both sides (the anode side and the cathode side) of the membrane electrode assembly, at least one porous group is obtained. A film-like sealing resin 200 is laminated on the periphery of the material 120. Next, the film-form sealing resin 200 is irradiated with laser light to melt the film-form seal resin 200 and impregnate the pores in the peripheral portion, as shown in FIG. Then, the sealing part 210 in which the sealing resin is impregnated in the pores at the peripheral part of the porous substrate is formed. Further, a sealing resin 200 for film-like sealing is disposed on the periphery of the opposite porous substrate 120, and the sealing portion is formed on the periphery of the opposite porous substrate 120 by irradiating laser light in the same manner. May be formed (not shown).

  By stacking 10 to 100 cells of the separator plate and the cooling unit alternately so that the anode side and the cathode side are on the predetermined side, the fuel cell obtained by joining the solid polymer fuel cells obtained by joining as described above You can assemble a stack. The assembly of the fuel cell stack can be performed by a conventionally known method.

Hereinafter, the present invention will be specifically described by way of examples.
Example 1
Production of Diffusion Layer Element A porous carbon paper (TGP-H-060, manufactured by Toray) having a size of 20 × 20 cm and a thickness of 200 μm was prepared as a sheet-like porous substrate. A water repellent treatment was performed on one surface by applying PTFE dispersion (manufactured by Daikin Industries, Polyflon PTFE · D-1) in an amount of 10% by mass with respect to the carbon paper. Further, a mixed solution of carbon black (Denka, Denka Black) and the PTFE dispersion having a mass ratio of 1: 1 is applied to the water repellent surface of the carbon paper so that a dry film having a thickness of 20 μm is obtained. Thus, a protective layer was formed.

A polycarbonate film having a size of 15 × 15 cm and a thickness of 50 μm was prepared as a film-form sealing resin, and a central portion of 5.5 × 5.5 cm was cut out to produce a frame-shaped film. The sheet-like porous substrate was cut to a size of 6 × 6 cm and placed on a table with the surface not subjected to water repellent treatment facing up. Next, the frame-shaped film is laminated so that an overlap area of 2.5 mm is generated at each peripheral edge of the porous base material, and the thickness is 0.8 cm and the size is 30 × 30 cm on the film. A transparent soda glass plate was placed. Then, a table was pressed against the glass plate with air pressure so that a pressure of 9.8 × 10 ⁵ Pa (10 kgf / cm ² ) was applied between the porous substrate and the film.

Next, a CO ₂ laser (wavelength 940 nm, spot diameter 2.7 mm, output 15 mW) was passed through the glass plate at a scanning speed of 10 mm / sec using a general-purpose laser resin welding machine (manufactured by Fine Devices, model FD-200). The overlap area was irradiated. The polycarbonate film in the region irradiated with the laser melted and impregnated into the pores of the porous carbon paper, and the step (50 μm) in the overlapping region of the polycarbonate film and the porous carbon film disappeared. Thereafter, the pressure was released, and the gas diffusion layer element in which the peripheral edge of the porous carbon film was sealed with polycarbonate was taken out.

Production of Membrane Electrode Assembly (MEA) Platinum ruthenium alloy (platinum / ruthenium mass ratio 1: 1) -supported carbon (carbon: alloy mass ratio 1: 1) and water were previously mixed at a mass ratio of 1: 3. This mixed solution and a 2.5% amount of Nafion (registered trademark) 20% by mass solution with respect to the platinum ruthenium alloy-supported carbon (manufactured by DuPont: SE-20092, ion exchange capacity: 0.9 milliequivalent / gram) And 18 times the amount of ethanol with respect to the platinum-ruthenium alloy-supporting carbon were uniformly mixed to prepare an anode catalyst layer forming coating solution having a solid content of 6% by mass. Further, platinum-supporting carbon (carbon: platinum mass ratio 1: 1) and water were previously mixed at a mass ratio of 1: 3. By uniformly mixing the mixed solution, the Nafion (registered trademark) 20% by mass solution of 2.5 times the platinum-supported carbon, and the ethanol amount 18 times the platinum-supported carbon. A cathode catalyst layer forming coating solution having a solid content concentration of 6% by mass was prepared. An ion exchange membrane GORE-SELECT (registered trademark) (manufactured by Japan Gore-Tex) with a size of 10 × 10 cm was prepared as a polymer electrolyte membrane. Moreover, the screen mesh (Mino group company make: T-70) containing the square cutting pattern of 5x5 cm in the center part was prepared. The screen mesh is placed on one side of the polymer electrolyte membrane, and the coating solution for anode catalyst layer formation is coated on the surface of the screen mesh and dried at 80 ° C. to repeat the coating / drying process. The anode catalyst layer having a thickness of 10 μm and a platinum ruthenium loading of 0.45 mg / cm ² was formed. Next, a screen mesh (Mino Group: T-70) including a 5 × 5 cm square cutout pattern in the center was prepared. The screen mesh is placed on the surface opposite to the anode catalyst layer of the ion exchange membrane, and the cathode catalyst layer forming coating solution is pattern coated thereon and dried at 80 ° C. By repeating the drying step, a cathode catalyst layer having a thickness of 10 μm corresponding to the cutout and a platinum loading of 0.4 mg / cm ² was formed, and an MEA was produced.

Production and Evaluation of Polymer Electrolyte Fuel Cell A polymer electrolyte fuel cell was produced by sticking the gas diffusion layer element on both sides of the MEA with the water-repellent treatment side being the MEA side. . As shown in FIG. 4, an adhesive sheet (manufactured by Nitto Shinko, FB-ML4) is disposed on one of the gas diffusion layer elements, and this is hot-pressed (temperature 150 ° C., pressure) on the other gas diffusion layer element. 5.0 MPa). The obtained polymer electrolyte fuel cell is mounted on a single cell for a fuel cell having an active area of 5 × 5 cm, the cell temperature is set to 80 ° C., and the dew point of hydrogen gas and air is set to 80 ° C. (relative humidity is 100% RH). The power generation performance was measured with hydrogen and oxygen utilization rates of 80% and 40%, respectively. In addition, a fuel cell leak test was performed as follows. The cell size including the molded frame was 7 × 7 cm, the electrode size was 5 × 5 cm, and the periphery was sandwiched and sealed with a silicon sheet having a thickness of 0.5 mm. This was incorporated into a separator and submerged, and one side of the cell was pressurized with air or helium. The other side of the pressurization surface was opened, and when the cell leaked air or helium, a bubble was generated from the other side. The pressure was increased from 0 MPa, and the pressure at the time when the generation of bubbles was confirmed visually was defined as the leak pressure.
In the operation of the polymer electrolyte fuel cell, there was no problem such as leakage, and a power generation performance of 0.68 V was obtained at a current density of 0.5 A / cm ² .

Example 2
Similarly to Example 1, the water-repellent treatment was performed on the porous carbon paper as the sheet-like porous substrate, and a protective layer was formed on the water-repellent surface. Further, an MEA was produced in the same manner as in Example 1. A basic structure of a polymer electrolyte fuel cell was prepared by attaching the porous carbon paper on both sides of the MEA with the water-repellent treatment side facing the MEA side.

A polyethersulfone (PES) film having a size of 15 × 15 cm and a thickness of 50 μm was prepared as a film-form sealing resin, and a central portion of 5.5 × 5.5 cm was cut out to produce a frame-shaped film. The basic structure was cut to a size of 6 × 6 cm and placed on a table. Next, the frame-like film is laminated so that an overlap region of 2.5 mm is generated at each peripheral edge of the porous carbon paper, and the thickness is 0.8 cm and the size is 30 × 30 cm on the film. A transparent soda glass plate was placed. Then, a table was pressed against the glass plate with air pressure so that a pressure of 9.8 × 10 ⁵ Pa (10 kgf / cm ² ) was applied between the porous substrate and the film.

Next, using the general-purpose laser resin welding machine, a CO ₂ laser (wavelength 940 nm, spot diameter 2.7 mm, output 10 mW) was irradiated to the overlapping region through a glass plate at a scanning speed of 5 mm / second. The PES film in the region irradiated with the laser melts and impregnates in the pores of the porous carbon paper, the step (50 μm) in the overlapping region of the PES film and the porous carbon film disappears, and the peripheral edge of the porous carbon film Was sealed with PES.

The obtained polymer electrolyte fuel cell was attached to an evaluation cell in the same manner as in Example 1, and the performance was measured. In the operation of the polymer electrolyte fuel cell, there was no problem such as leakage, and a power generation performance of 0.68 V was obtained at a current density of 0.5 A / cm ² .

Comparative Example 1
The porous carbon film was impregnated with the porous carbon film in the same manner as in Example 1 except that the porous carbon film was impregnated by hot pressing at 150 ° C., 2 MPa for 2 minutes instead of laser irradiation. A gas diffusion layer element having a peripheral edge sealed with polycarbonate was produced. Using this element, a polymer electrolyte fuel cell was produced in the same manner as in Example 1, and the performance was evaluated by mounting it on an evaluation cell. However, since the sealing was insufficient and the reaction gas leaked, performance evaluation could not be performed. This is due to the occurrence of distortion after hot pressing due to the difference in linear thermal expansion coefficient between the polycarbonate film and the carbon film.

Comparative Example 2
The porous carbon film was impregnated with a porous carbon film in the same manner as in Example 2 except that the porous carbon film was impregnated by hot pressing under conditions of 150 ° C., 2 MPa, 2 minutes instead of laser irradiation. A polymer electrolyte fuel cell having a peripheral edge sealed with polycarbonate was produced. This polymer electrolyte fuel cell was mounted in an evaluation cell and performance was evaluated. However, since the sealing was insufficient and the reaction gas leaked, performance evaluation could not be performed. This is due to the occurrence of distortion after hot pressing due to the difference in linear thermal expansion coefficient between the polycarbonate film and the carbon film.

11 Polymer Electrolyte Membrane 12 Porous Catalyst Electrode 13 Separator 14 Membrane Electrode Assembly (MEA)
DESCRIPTION OF SYMBOLS 15 Packing 21 Resin sealing part 100 Gas diffusion layer element 120 Sheet-like porous base material 200 Film-like sealing resin 210 Sealing part 250 Adhesive 300 Membrane electrode assembly 310 Polymer electrolyte membrane 320 Catalyst layer

Claims (7)

A step of laminating and arranging a film-like sealing resin having a thickness in the range of 10 to 80% of the thickness of the sheet-like porous substrate on the periphery of the sheet-like porous substrate;
Irradiating the film-form sealing resin with a laser beam to melt the film-form seal resin and impregnating the film-form seal resin into the pores of the peripheral portion. Solid polymer fuel containing a sealing resin impregnated in pores at the peripheral edge of the porous substrate, wherein the resin for sealing the film is pressed against the porous substrate. A method for producing a gas diffusion layer element for a battery.   2. The production according to claim 1, wherein, when irradiating the laser beam, the resin for sealing the film is pressed against the porous sheet-like substrate by applying a pressure with a laser-transmissive substrate. Method. A step of laminating and arranging a film-like sealing resin having a thickness in the range of 10 to 80% of the thickness of the sheet-like porous substrate on the periphery of the sheet-like porous substrate;
By irradiating the film-form sealing resin with laser light, the film-form seal resin is melted and impregnated in the pores of the peripheral portion, and the pores in the peripheral portion of the porous base material are impregnated. Obtaining a gas diffusion layer element comprising an impregnated sealing resin;
The gas diffusion layer element as a gas diffusion layer on at least one side, and a step of combining the membrane electrode assembly and the gas diffusion layer on the opposite side in order with the gas diffusion layer element. A method for producing a polymer electrolyte fuel cell, in which a resin for encapsulating is pressed against the sheet-like porous substrate.   4. The production according to claim 3, wherein, when irradiating the laser light, the resin for sealing the film is pressed against the sheet-like porous base material by applying a pressure with a laser light transmitting substrate. Method. In order, combining the anode side gas diffusion layer, the membrane electrode assembly and the cathode side gas diffusion layer,
A step of laminating and arranging a film-like sealing resin having a thickness in the range of 10 to 80% of the thickness of the gas diffusion layer on the periphery of the gas diffusion layer on at least one side;
Irradiating the film-form sealing resin with a laser beam to melt the film-form seal resin and impregnating the film-form seal resin into the pores of the peripheral portion. The method for producing a polymer electrolyte fuel cell, wherein the film-like sealing resin is pressed against the gas diffusion layer. Further, a step of laminating and arranging a film-like sealing resin having a thickness in the range of 10 to 80% of the thickness of the gas diffusion layer on the peripheral portion of the gas diffusion layer on the opposite side;
A step of melting the film-form sealing resin by irradiating the film-form sealing resin with a laser beam and impregnating it in the pores of the peripheral portion, The manufacturing method according to claim 5, wherein the film-form sealing resin is pressed against the gas diffusion layer.   The manufacturing method according to claim 5 or 6, wherein when irradiating the laser beam, the resin for sealing the film is pressed against the gas diffusion layer by applying a pressure with a substrate transparent to the laser beam. .

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