JP2014067483A - Method for manufacturing solid polymer fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the decrease in the thickness of a solid polymer electrolytic film when transferring an electrode catalyst layer to the solid polymer electrolytic film by a decal process.SOLUTION: A method for manufacturing a solid polymer fuel cell comprises the steps of: applying paste for a catalyst layer 64 to a base material 60 with a mask 62 provided thereon, followed by a provisional drying; subsequently removing the mask 62 while the paste for the catalyst layer 64 is still in wet condition; and thereafter, solidifying the paste for the catalyst layer 64 by a regular drying, thereby forming a first electrode catalyst layer 26 (or second electrode catalyst layer 30). In the method, the first electrode catalyst layer 26 (or second electrode catalyst layer 30) is transferred from the base material 60 to an electrolytic film 18 by means of thermocompression.

Description

  The present invention relates to a method for producing a polymer electrolyte fuel cell having an electrolyte membrane / electrode structure in which an anode electrode and a cathode electrode are configured by sandwiching a polymer electrolyte membrane.

  As is well known, a polymer electrolyte fuel cell is composed of a solid polymer electrolyte membrane (hereinafter sometimes simply referred to as “electrolyte membrane”) made of a solid polymer membrane, which is a proton conductor, as an anode electrode and a cathode electrode. A sandwiched electrolyte membrane / electrode assembly (MEA) is provided. This MEA is sandwiched between a pair of separators to constitute a unit cell. Generally, a polymer electrolyte fuel cell is configured as a stack by stacking a plurality of the unit cells.

  The anode electrode and the cathode electrode are composed of a gas diffusion layer and an electrode catalyst layer interposed between the gas diffusion layer and the electrolyte membrane. The gas diffusion layer is made of, for example, carbon paper or carbon cloth, and the electrode catalyst layer is, for example, a catalyst carrier (carbon black or the like) carrying metal particles such as platinum particles bonded through an ion conductive binder. It is formed by being integrated.

  For example, the MEA is manufactured as follows. That is, first, a catalyst layer paste to be an electrode catalyst layer is applied to a base material provided with a mask.

  Next, the paste for the catalyst layer is housed in a dryer such as an oven together with the base material and the mask, and is dried by being kept at a predetermined temperature. Thereby, the electrode catalyst layer as a solidified product is formed. Thereafter, the mask is peeled off.

  Next, after interposing an electrolyte membrane between the electrode catalyst layers of the two substrates, the electrode catalyst layer is transferred from the substrate to the electrolyte membrane by thermocompression bonding. Thereby, the electrolyte membrane provided with the electrode catalyst layer on both end faces is obtained.

  Furthermore, MEA is obtained by laminating | stacking a gas diffusion layer with respect to each of two electrode catalyst layers.

  Here, after the catalyst layer paste is solidified (in other words, after the electrode catalyst layer is formed), when the mask is peeled off from the substrate, the outer peripheral edge of the electrode catalyst layer 1 as shown in FIG. The vicinity tends to be a raised portion 2 having a relatively sharp apex. Note that reference numeral 3 in FIG. 7 indicates a base material to which a catalyst layer paste is applied.

  As shown in FIG. 8, when such an electrode catalyst layer 1 is transferred to the electrolyte membrane 4, the raised portions 2 bite into the electrolyte membrane 4. For this reason, the malfunction that the thickness of the electrolyte membrane 4 becomes small is caused. If the thickness of the electrolyte membrane 4 is excessively reduced, the fuel gas easily moves to the cathode electrode through the electrolyte membrane 4 while the oxidant gas easily moves to the anode electrode. For this reason, so-called gas crossover easily occurs.

  Therefore, it is recalled that the electrode catalyst layer 1 is formed while avoiding the formation of the raised portion 2. For example, as described in Patent Document 1 and Patent Document 2, if the outer peripheral edge portion of the electrode catalyst layer is an inclined portion, the raised portion 2 is not formed, and accordingly, the raised portion 2 becomes the electrolyte membrane 4. It is thought that it is avoided to bite into.

JP 2011-138657 A JP 2007-59340 A

  In the techniques described in Patent Documents 1 and 2, the catalyst layer paste is directly applied to the electrolyte membrane, and the catalyst layer paste is dried to form an electrode catalyst layer. It is not easy to apply to the electrolyte membrane. Actually, the MEA is generally produced by the above transfer (decal method).

  However, in the decal method, as described above, the problem that the raised portion is relatively easily formed is obvious.

  The present invention has been made in order to solve the above-described problems, and can prevent the thickness of the electrolyte membrane from being reduced at the time of transfer. Therefore, it is possible to manufacture a polymer electrolyte fuel cell in which gas crossover hardly occurs. It aims to provide a method.

In order to achieve the above object, the present invention provides a method for producing a polymer electrolyte fuel cell having an electrolyte membrane / electrode structure in which an anode electrode and a cathode electrode are sandwiched between solid polymer electrolyte membranes.
Providing a mask on the substrate;
Applying the catalyst layer paste to the base material on which the mask is formed, and then temporarily drying the catalyst layer paste;
While the catalyst layer paste contains a solvent and is in a wet state, the mask is removed and a part of the outer peripheral edge of the catalyst layer paste is removed from the base material along with the mask. Process,
The step of main drying the catalyst layer paste, and obtaining an electrode catalyst layer on the substrate, the outer peripheral edge of which is tapered as it becomes the edge tip as the thickness direction dimension changes;
Transferring the electrode catalyst layer from the substrate to the solid polymer electrolyte membrane;
Laminating a gas diffusion layer on the electrode catalyst layer to obtain the anode electrode or the cathode electrode;
It is characterized by having.

  In this way, by removing the mask when the catalyst layer paste is solidified to a certain extent but still contains a solvent and is in a semi-dry state, and then performing a main drying to obtain a solidified product. Thus, an electrode catalyst layer having a tapered edge at the outer peripheral edge can be obtained. For this reason, it is avoided that the protruding part shown in FIG. 7 is formed in the outer peripheral edge part of the electrode catalyst layer.

  As a result, when the electrode catalyst layer is transferred from the substrate to the solid polymer electrolyte membrane, the ridges bite into the solid polymer electrolyte membrane, and the thickness of the solid polymer electrolyte membrane is reduced due to the bite. It is avoided. Therefore, gas crossover is unlikely to occur.

  That is, according to the present invention, it is possible to obtain a polymer electrolyte fuel cell in which gas crossover hardly occurs while employing the decal method.

  In addition, since the load is prevented from locally concentrating as the raised portion presses the solid polymer electrolyte membrane during transfer, the solid polymer electrolyte membrane is also prevented from being damaged.

  The tip of the tapered edge of the outer peripheral edge can be formed as an inclined portion, for example. The electrode including the electrode catalyst layer having the outer peripheral edge portion having such a shape may be either an anode electrode or a cathode electrode, but is most preferably both an anode electrode and a cathode electrode.

  According to the present invention, when the catalyst layer paste is in a semi-dried state, the mask is removed, and then this drying is performed to obtain a solidified product (electrode catalyst layer). The edge of the outer peripheral edge can be tapered to avoid the formation of a raised portion. For this reason, when the electrode catalyst layer is transferred from the substrate to the solid polymer electrolyte membrane, it is avoided that the ridges bite into the solid polymer electrolyte membrane, and the thickness of the solid polymer electrolyte membrane is caused by this bite. Is reduced.

  For the reasons described above, it is possible to obtain a polymer electrolyte fuel cell in which gas crossover hardly occurs while employing the decal method.

  In addition, it is avoided that the raised portion presses the solid polymer electrolyte membrane due to biting, so that the load is prevented from being concentrated locally on the solid polymer electrolyte membrane. This avoids damage to the solid polymer electrolyte membrane.

It is a principal part disassembled perspective view of the unit cell which comprises a polymer electrolyte fuel cell. It is a principal part expanded sectional view in alignment with the lamination direction of the electrolyte membrane and electrode structure (MEA) which comprises the said unit cell. It is a top view of a 1st electrode catalyst layer (or 2nd electrode catalyst layer). FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1. It is a schematic flowchart of the manufacturing method which concerns on this Embodiment for obtaining MEA of FIG. It is a principal part expanded sectional view along the thickness direction of the paste for catalyst layers formed on the base material. It is a principal part expanded sectional view in alignment with the thickness direction of the electrode catalyst layer formed on the base material by the manufacturing method which concerns on a prior art. It is a principal part expanded sectional view along the thickness direction which shows the state after transcribe | transferring the electrode catalyst layer of FIG. 7 to a solid polymer electrolyte membrane.

  Preferred embodiments of the method for producing a polymer electrolyte fuel cell according to the present invention will be described below in detail with reference to the accompanying drawings.

  First, the structure of the polymer electrolyte fuel cell obtained by the manufacturing method according to the present embodiment will be described with reference to FIGS.

  The polymer electrolyte fuel cell is configured as a stack by stacking a plurality of unit cells 10 shown in FIG. In addition, the arrow X, the arrow Y, and the arrow Z in FIG. 1 respectively represent the stacking direction, the width direction, and the height direction of the unit cell 10, and the same applies to the subsequent drawings.

  The unit cell 10 includes an electrolyte membrane / electrode structure (MEA) 12, and a first separator 14 and a second separator 16 that sandwich the MEA 12.

  The MEA 12 includes, for example, an electrolyte membrane (solid polymer electrolyte membrane) 18 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode electrode 20 and a cathode electrode 22 that sandwich the electrolyte membrane 18. In this case, the electrolyte membrane 18 is set to have a larger area than the anode electrode 20 and the cathode electrode 22. The electrolyte membrane 18 may be set to have the same area as the anode electrode 20 and the cathode electrode 22. The areas of the anode electrode 20 and the cathode electrode 22 may be different.

  As shown in FIG. 2, the anode electrode 20 includes a first gas diffusion layer 24 facing the first separator 14 (see FIG. 1), and a first electrode interposed between the first gas diffusion layer 24 and the electrolyte membrane 18. The catalyst layer 26 is configured. Similarly, the cathode electrode 22 includes a second gas diffusion layer 28 facing the second separator 16 (see FIG. 1), and a second electrode catalyst layer 30 interposed between the second gas diffusion layer 28 and the electrolyte membrane 18. Is done. The first gas diffusion layer 24 and the second gas diffusion layer 28 are made of, for example, carbon paper or carbon cloth, while the first electrode catalyst layer 26 and the second electrode catalyst layer 30 are made of, for example, a catalyst such as platinum particles. A supported catalyst carrier (carbon black or the like) is formed by being combined and integrated through an ion conductive binder.

  Here, at the outer peripheral edge portion 26 a of the first electrode catalyst layer 26, the dimension in the arrow X direction (stacking direction), in other words, the thickness direction dimension becomes smaller toward the outer peripheral side of the first gas diffusion layer 24. That is, the outer peripheral edge portion 26 a of the first electrode catalyst layer 26 is an inclined portion that is inclined so as to expand toward the first gas diffusion layer 24. Similarly, in the second electrode catalyst layer 30, the outer peripheral edge portion 30 a becomes smaller toward the outer peripheral side of the second gas diffusion layer 28. Therefore, the outer peripheral edge portions 26a, 30a of the first electrode catalyst layer 26 and the second electrode catalyst layer 30 are as shown in FIG. 3 in which the illustration of the first gas diffusion layer 24 to the second gas diffusion layer 28 is omitted. In other words, the shape is a so-called tapered shape that tapers as it reaches the front end of the edge such as the front end in the width direction (arrow Y direction) and the front end in the height direction (arrow Z direction). Here, in FIG. 3, in order to facilitate understanding, the degree of inclination is shown exaggerated from the actual level.

  The positions of the outer peripheral edge of the first electrode catalyst layer 26 and the outer peripheral edge of the second electrode catalyst layer 30 are preferably shifted from each other.

  Further, the outer peripheral edge portions 26a, 30a (inclined portions) of the first electrode catalyst layer 26 and the second electrode catalyst layer 30 are formed by the first gas diffusion layer 24 and the second gas diffusion layer 28 as shown in FIG. It is go.

  The first separator 14 and the second separator 16 (see FIG. 1) sandwiching the MEA 12 as described above are, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a surface treatment for corrosion prevention on the metal surface. It is composed of applied metal plates, carbon members, and the like.

  As shown in FIG. 1, an oxidant gas inlet for supplying an oxidant gas to one end edge of the unit cell 10 in the arrow Y direction (width direction) in communication with each other in the arrow X direction which is the stacking direction. A communication hole 32, a cooling medium inlet communication hole 34 for supplying the cooling medium, and a fuel gas outlet communication hole 36 for discharging the fuel gas are arranged in the arrow Z direction (height direction).

  Further, the other end edge of the unit cell 10 in the direction of arrow Y communicates with each other in the direction of arrow X, a fuel gas inlet communication hole 38 for supplying fuel gas, and a cooling medium outlet for discharging the cooling medium. A communication hole 40 and an oxidant gas outlet communication hole 42 for discharging the oxidant gas are arranged in the arrow Z direction.

  Further, a fuel gas passage 44 communicating with the fuel gas inlet communication hole 38 and the fuel gas outlet communication hole 36 is formed on the end surface 14a facing the MEA 12 of the first separator 14, and the end surface 14b which is the back surface thereof is formed on the end surface 14b. A supply hole 46 for communicating the fuel gas inlet communication hole 38 with the fuel gas flow path 44 and a discharge hole 48 for communicating the fuel gas flow path 44 with the fuel gas outlet communication hole 36 are formed.

  On the other hand, an oxidant gas flow path 50 that communicates with the oxidant gas inlet communication hole 32 and the oxidant gas outlet communication hole 42 is provided on the end face 16 a facing the MEA 12 of the second separator 16. As shown in FIGS. 1 and 4, between the end surface 14 b of the first separator 14 and the end surface 16 b of the second separator 16, the cooling medium inlet communication hole 34 and the cooling medium outlet communication hole 40 (both in FIG. 1). A cooling medium flow path 52 communicating with the reference is formed.

  For example, an oxygen-containing gas such as air is selected as the oxidant gas, and a hydrogen-containing gas such as hydrogen is selected as the fuel gas. Moreover, as a cooling medium, water, an organic solvent, oil, etc. are used, for example.

  As shown in FIGS. 1 and 4, end surfaces 14 a and 14 b of the first separator 14 are provided with a first seal member 54 so as to go around the outer peripheral end of the first separator 14. A second seal member 56 that goes around the outer peripheral end portion is also provided on the end surfaces 16 a and 16 b of the second separator 16. Examples of the first seal member 54 and the second seal member 56 include ethylene-propylene-diene (EPDM) rubber, acrylonitrile butadiene (NBR) rubber, fluorine compound rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, An elastic material such as a sealing material such as styrene rubber, chloroplane or acrylic rubber, a cushioning material, or a packing material is used.

  Basically, the polymer electrolyte fuel cell in which a plurality of unit cells 10 configured as described above are stacked operates as follows.

  First, as shown in FIG. 1, an oxidant gas such as air is supplied to the oxidant gas inlet communication hole 32, and a fuel gas such as hydrogen is supplied to the fuel gas inlet communication hole 38. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 34.

  The fuel gas is introduced from the fuel gas inlet communication hole 38 through the supply hole 46 into the fuel gas flow path 44 of the first separator 14, and then moves in the arrow Y direction along the fuel gas flow path 44. The anode electrode 20 is supplied. In the anode electrode 20, the fuel gas passes through the first gas diffusion layer 24 (see FIG. 2) while diffusing and reaches the first electrode catalyst layer 26.

  Thereafter, in the first electrode catalyst layer 26, a reaction occurs in which hydrogen in the fuel gas is ionized to generate protons. The protons move to the second electrode catalyst layer 30 of the cathode electrode 22 by the proton conduction action of the electrolyte membrane 18. The electrons are used as an electrical energy source for energizing an external load electrically connected to the polymer electrolyte fuel cell.

  On the other hand, the oxidant gas is introduced into the oxidant gas flow path 50 of the second separator 16 from the oxidant gas inlet communication hole 32, moves in the arrow Y direction, and is supplied to the cathode electrode 22 of the MEA 12.

  In the cathode electrode 22, the oxidant gas passes through the second gas diffusion layer 28 (see FIG. 2) while diffusing and reaches the second electrode catalyst layer 30. Thereafter, in the second electrode catalyst layer 30, oxygen in the oxidant gas, protons that have moved through the electrolyte membrane 18, and electrons that have reached the cathode electrode 22 by energizing the external load react with each other, thereby Generate.

  Here, the fuel gas consumed by being supplied to the anode electrode 20 passes through the discharge hole portion 48 and is discharged in the direction of the arrow X along the fuel gas outlet communication hole 36. Similarly, the oxidant gas supplied to and consumed by the cathode electrode 22 is discharged in the direction of the arrow X along the oxidant gas outlet communication hole 42.

  While power generation is performed as described above, the cooling medium is supplied to the cooling medium flow path 52 between the first separator 14 and the second separator 16 via the cooling medium inlet communication hole 34. The cooling medium is discharged from the cooling medium outlet communication hole 40 after cooling the MEA 12 by flowing in the arrow Y direction.

  During this time, gas crossover is reduced. The reason for this will be described later.

  Next, the manufacturing method of the unit cell 10 configured as described above will be described in detail with reference to FIG.

  First, as shown to Fig.5 (a), the base material 60 is produced by cutting out a polytetrafluoroethylene sheet | seat etc. to a rectangular shape.

  Next, a rectangular mask 62 is provided on the substrate 60 as shown in FIG. For this purpose, for example, a film such as Hitachilex manufactured by Hitachi Chemical Co., Ltd. may be attached to the substrate 60.

  Next, as shown in FIG. 5C, a catalyst layer paste 64 is applied. Suitable coating methods in this case include screen printing, inkjet, blade coater, slot die, and the like. FIG. 5C illustrates a blade coater using a blade 66.

  The catalyst layer paste 64 is prepared by mixing a polymer solution serving as an ion conductive polymer binder with a solvent to which catalyst support (carbon black or the like) particles supporting catalyst particles such as platinum particles are added. can do. The catalyst layer paste 64 is applied so that catalyst particles (platinum particles and the like) are in a predetermined amount.

  In the manufacturing method according to the prior art, the catalyst layer paste is heat-treated immediately after the catalyst layer paste is applied. By this heat treatment, the catalyst layer paste is dried to become a solidified product, and an electrode catalyst layer is formed.

  On the other hand, in the present embodiment, as shown in FIG. 5D, the catalyst layer paste 64 is allowed to stand at room temperature, for example, and is temporarily dried. That is, the solvent contained in the catalyst layer paste 64 is volatilized to some extent, and the catalyst layer paste 64 is semi-dried, in other words, a semi-solidified product. The temporary drying may be continued until, for example, the viscosity of the catalyst layer paste 64 becomes such that the shape can be maintained when the mask 62 is removed. When left at room temperature, the preferred standing time is 10 seconds to 5 minutes. Of course, an appropriate drying means such as a dryer may be used so that the semi-dry state can be achieved in a shorter time.

  Next, the mask 62 is removed while the catalyst layer paste 64 is still wet with the solvent. When the mask 62 is a film as described above, the mask 62 may be peeled off from the substrate 60 as shown in FIG.

  Along with this removal, a part of the outer peripheral edge of the catalyst layer paste 64 is removed along with the mask 62. As a result, as shown in FIG. 6, the outer peripheral edge portion 64 a becomes an inclined portion that is inclined so that, for example, the thickness direction (arrow X direction) dimension becomes smaller toward the outer peripheral side. The reason is that the semi-dried catalyst layer paste 64 flows to the outer peripheral side by its own weight. Therefore, after removing the mask 62, the surface area of the catalyst layer paste 64 is larger than the opening area of the mask 62. Further, the inclined portion tapers as it becomes the tip of the edge such as the tip in the width direction (arrow Y direction), the tip in the height direction (arrow Z direction), or the like.

  Next, the catalyst layer paste 64 is fully dried. That is, for example, as shown in FIG. 5 (f), the catalyst layer paste 64 is housed in a dryer such as an oven 68 together with the base material 60 and is dried by being kept at a predetermined temperature. Thereby, as shown in FIG. 5G, the first electrode catalyst layer 26 as a solidified product is formed on the substrate 60. Since the outer peripheral edge portion 64a of the catalyst layer paste 64 is an inclined portion as described above, the outer peripheral edge portion 26a of the first electrode catalyst layer 26 is also inclined so as to become smaller toward the outer peripheral side, that is, It is a taper-shaped part which tapers as it becomes a front-end | tip part with a change of the thickness direction dimension.

  The second electrode catalyst layer 30 can also be obtained by the same operation as described above. The outer peripheral edge portion 30a of the second electrode catalyst layer 30 is also an inclined portion that is inclined so that the thickness direction dimension becomes smaller toward the outer peripheral side, in other words, the front end in the width direction as the thickness direction dimension changes. It becomes the taper-shaped part which tapers off as it becomes. The amount of catalyst particles (platinum particles, etc.) in the catalyst layer paste for providing the second electrode catalyst layer 30 may be the same as that of the catalyst layer paste 64 on which the first electrode catalyst layer 26 is formed. , May be different. Further, the composition may be different between the catalyst layer paste and the catalyst layer paste 64.

  Next, the first electrode catalyst layer 26 and the second electrode catalyst layer 30 are transferred to the electrolyte membrane 18 by, for example, a decal method. That is, after sandwiching the electrolyte membrane 18 with the base material 60 so that the first electrode catalyst layer 26 and the second electrode catalyst layer 30 are in contact with the electrolyte membrane 18, as shown in FIG. Apply thermocompression bonding. Then, if the base materials 60 and 60 are peeled from the first electrode catalyst layer 26 and the second electrode catalyst layer 30, the first electrode catalyst layer 26 and the second electrode catalyst layer 30 remain on the electrolyte membrane 18. That is, as shown in FIG. 5 (i), the electrolyte membrane 18 (so-called CCM) in which the first electrode catalyst layer 26 and the second electrode catalyst layer 30 are respectively provided on both end surfaces is formed.

  As described above, the outer peripheral edge portions 26a and 30a of the first electrode catalyst layer 26 and the second electrode catalyst layer 30 on the base material 60 are inclined portions that are inclined so as to become smaller as the thickness direction dimension becomes the outer peripheral side. (See FIG. 6). Accordingly, the raised portions 2 shown in FIG. 7 do not exist at the outer peripheral edge portions 26 a and 30 a of the first electrode catalyst layer 26 and the second electrode catalyst layer 30.

  For this reason, when the first electrode catalyst layer 26 and the second electrode catalyst layer 30 are transferred to the electrolyte membrane 18, the raised portion 2 does not bite into the electrolyte membrane 18. As a result, a reduction in the thickness of the electrolyte membrane 18 is avoided. For example, when the raised portion 2 exists, the thickness of the electrolyte membrane 4 is reduced to 77% before the transfer with the transfer, whereas according to the present embodiment, the thickness of the electrolyte membrane 18 is the same as that before the transfer. 99% or more. For this reason, it is difficult for gas crossover to occur.

  Further, since the raised portion 2 does not exist, it is avoided that the load is locally concentrated on the electrolyte membrane 18 during the transfer. For this reason, damage to the electrolyte membrane 18 is also avoided.

  In the first electrode catalyst layer 26 and the second electrode catalyst layer 30 transferred to the electrolyte membrane 18, the dimensions in the thickness direction of the outer peripheral edge portions 26a and 30a become smaller toward the outer peripheral side (see FIG. 2).

  Thus, while providing the 1st electrode catalyst layer 26 and the 2nd electrode catalyst layer 30 in the both end surfaces of the electrolyte membrane 18, it is for diffusion layers for forming the 1st gas diffusion layer 24 and the 2nd gas diffusion layer 28 Prepare paste. That is, for example, a diffusion layer paste is obtained by dispersing a mixture of carbon black particles and polytetrafluoroethylene particles in a predetermined weight ratio in an appropriate solvent, and then the diffusion layer paste is carbon paper or After apply | coating to the base material which consists of porous materials, such as carbon cloth, this is dried and a base layer is formed. Thereby, the 1st gas diffusion layer 24 and the 2nd gas diffusion layer 28 which consist of a base material and a base layer are obtained, respectively.

  Next, in order to produce the MEA 12 (see FIG. 1) from the CCM, the first gas diffusion layer 24 is laminated on the end face of the first electrode catalyst layer 26 and the second gas is put on the end face of the second electrode catalyst layer 30. A diffusion layer 28 is stacked. That is, the base layers of the first gas diffusion layer 24 and the second gas diffusion layer 28 are laminated on the exposed end surfaces of the first electrode catalyst layer 26 and the second electrode catalyst layer 30, respectively. Here, each base layer is set to an area that can cover the entire surfaces of the first electrode catalyst layer 26 and the second electrode catalyst layer 30.

  Further, the first electrode catalyst layer 26, the second electrode catalyst layer 30, and the respective underlayers are bonded to each other by performing thermocompression bonding with a hot press machine 70, whereby the anode electrode 20 and the cathode are formed on each end face of the electrolyte membrane 18. The electrodes 22 are formed, and the MEA 12 is obtained.

  The unit cell 10 is obtained by holding the MEA 12 between the first separator 14 and the second separator 16. Further, by stacking a plurality of unit cells 10 thus obtained, a solid polymer fuel cell is configured as a stack.

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

  For example, in the above-described embodiment, the case where the outer peripheral edge portions 26a and 30a of the first electrode catalyst layer 26 and the second electrode catalyst layer 30 are inclined so as to expand as the distance from the electrolyte membrane 18 increases. However, conversely, it may be inclined so as to expand as it approaches the electrolyte membrane 18.

  Further, the outer peripheral edge portions 26a and 30a may have a shape such that the tip of the edge such as the tip in the width direction (arrow Y direction) or the tip in the height direction (arrow Z direction) is tapered, and is particularly limited to the inclined portion. Is not to be done. For example, the thickness direction (lamination direction / arrow X direction) section may be an arc shape, a curved shape, or a parabolic shape.

  Furthermore, in this embodiment, the outer peripheral edge portions 26a, 30a of the first electrode catalyst layer 26 and the second electrode catalyst layer 30 are surrounded by the first gas diffusion layer 24 and the second gas diffusion layer 28. However, instead of this, it may be surrounded by an adhesive layer formed of a fluorine-based adhesive or the like.

DESCRIPTION OF SYMBOLS 2 ... Raised part 3, 60 ... Base material 4, 18 ... Electrolyte membrane (solid polymer electrolyte membrane) 10 ... Unit cell 12 ... Electrolyte membrane electrode assembly (MEA) 14 ... 1st separator 16 ... 2nd separator 20 ... Anode electrode 22 ... Cathode electrode 24 ... First gas diffusion layer 26 ... First electrode catalyst layer 26a, 30a ... Outer peripheral edge 28 ... Second gas diffusion layer 30 ... Second electrode catalyst layer 32 ... Oxidant gas inlet communication hole 34 ... cooling medium inlet communication hole 36 ... fuel gas outlet communication hole 38 ... fuel gas inlet communication hole 40 ... cooling medium outlet communication hole 42 ... oxidant gas outlet communication hole 44 ... fuel gas flow path 50 ... oxidant gas flow path 52 ... Cooling medium flow path 62 ... Mask 64 ... Paste for catalyst layer 68 ... Oven 70 ... Hot press machine

Claims (2)

In a method for producing a polymer electrolyte fuel cell having an electrolyte membrane / electrode structure in which an anode electrode and a cathode electrode are sandwiched between solid polymer electrolyte membranes,
Providing a mask on the substrate;
Applying the catalyst layer paste to the base material on which the mask is formed, and then temporarily drying the catalyst layer paste;
While the catalyst layer paste contains a solvent and is in a wet state, the mask is removed and a part of the outer peripheral edge of the catalyst layer paste is removed from the base material along with the mask. Process,
The step of main drying the catalyst layer paste, and obtaining an electrode catalyst layer on the substrate, the outer peripheral edge of which is tapered as it becomes the edge tip as the thickness direction dimension changes;
Transferring the electrode catalyst layer from the substrate to the solid polymer electrolyte membrane;
Laminating a gas diffusion layer on the electrode catalyst layer to obtain the anode electrode or the cathode electrode;
A method for producing a polymer electrolyte fuel cell, comprising:   2. The method for producing a polymer electrolyte fuel cell according to claim 1, wherein an outer peripheral edge portion of at least one of the anode electrode and the cathode electrode is formed as an inclined portion. .

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