JP2003168449A - Manufacturing method of film electrode conjugate for solid polymer-type fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a membrane electrode conjugate for a solid polymer-type fuel cell wherein the composition of a catalyst layer or the like is made to be continuously changed by simple methods and wherein reaction efficiency is homogenized. <P>SOLUTION: A guide insulation wall 9 to separate plural kinds of coating solutions A, B is formed at an injection port 31 of a die 1 for a cast film- forming, and because the direction of the partition is made to be tilted against the casting direction X, catalyst layers 105a, 105b or a polymer electrolyte membrane 103 are formed so that the plural kinds of coating solutions A, B are tilted and overlapped at least at one part of a coating layer 11. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a membrane electrode assembly for a polymer electrolyte fuel cell, and more particularly to a reaction efficiency by eliminating the non-uniformity of current density in the plane of the membrane electrode assembly. The present invention relates to a method for producing a membrane electrode assembly for a polymer electrolyte fuel cell having improved temperature by a simple method.

[0002]

2. Description of the Related Art Fuel cells are expected to be widely used in the future because of their high power generation efficiency and low environmental load. Among them, polymer electrolyte fuel cells have high power density and low operating temperature, so they are easier to miniaturize and lower in cost than other fuel cells. Is expected to be widely used as a cogeneration system for

Generally, a membrane electrode assembly 101 of a polymer electrolyte fuel cell has, as shown in a sectional view in FIG. 4, catalyst layers 105a and 105b for an anode and a cathode on both sides of a polymer electrolyte membrane 103 made of an ion exchanger polymer. Are bonded to each other, and carbon paper, carbon cloth, or the like is arranged as the gas diffusion layers 107a and 107b on the outside thereof.

A conductive separator 109 is arranged outside the gas diffusion layers 107a and 107b. Gas flow paths 111a and 111b are formed in the separator 109 so as to face the gas diffusion layers 107a and 107b. The gas flow path is specifically, as shown in FIG. 5 or 6, an inlet 109a.
Series groove 111c, parallel groove 111 from the outlet to the outlet 109b
There are various modes such as d.

As described above, the membrane electrode assembly 101 includes the catalyst layer 105 containing the noble metal on both sides of the polymer electrolyte membrane 103.
It is formed by joining a and 105b. This catalyst layer 105
In forming a and 105b, a catalyst layer forming ink containing a dispersion liquid of catalyst-supporting carbon and a solid polymer electrolyte resin (for example, a perfluorocarbon polymer having a sulfonic acid group) as a main component is directly formed on the polymer electrolyte membrane 103. The coating method or the catalyst layers 105a and 105b formed by applying the ink in advance on a base material to form a sheet is formed on the polymer electrolyte membrane 103 by means such as hot pressing.

As a specific method for producing the catalyst layers 105a and 105b on the substrate, there is a method of forming on the coated substrate 125 using the die 121 shown in FIG. In this method, for example, the above-mentioned catalyst layer forming ink is applied onto the coating base material 125 to form one catalyst layer 105a. Further, using the die 121, the catalyst layer 105
It is also possible to cast the dispersion liquid of the ion-exchanger polymer on a and stack the polymer electrolyte membrane 103 to form it. Conversely, the polymer electrolyte membrane 103 may be first cast-formed and the catalyst layer 105a may be formed thereon.

The membrane electrode assembly 101 of the polymer electrolyte fuel cell configured as described above allows the fuel gas and the oxidant gas to pass through the gas passages 111a and 111b of the separator 109, and at the same time, the gas diffusion layer 107a. , 107b
Can transmit electric current to the outside and take out electric energy.

In the membrane electrode assembly 101, a cell reaction occurs when receiving gas supplied from the separator 109. The supplied gas is consumed by the cell reaction, and reaction products such as water are generated, so that the composition of the reaction gas and the humidification state of the gas change along the gas flow path, and as a result, the reaction conditions also change. It changes along the gas flow path. Due to this change in conditions, the current density becomes non-uniform within the surface of the membrane electrode assembly 101, which is one factor of deterioration in characteristics.

Regarding this problem, in order to ensure uniform reaction efficiency over the entire surface of the membrane electrode assembly 101, it has been proposed to change the amount of catalyst from the inlet 109a to the outlet 109b of the gas passage ( For example, Patent Document 1,
2 etc.). The specific method is to change the catalyst coating amount by utilizing a concentration gradient according to the distance in spray coating or by utilizing a concentration change according to the number of times of screen printing coating overcoating.

[Patent Document 1] Japanese Unexamined Patent Publication No. 3-245463 (Claims, Examples)

[Patent Document 2] Japanese Patent Laid-Open No. 2000-149959 (Claims, Examples 1 to 3)

[0010]

However, the catalyst layers 105a, 1a of the membrane electrode assembly 101 are formed by spray coating.
Changing the coating amount of 05b requires a high degree of control of the coating thickness. Also, when applying by screen printing,
Intricate coating processes and gradual changes in coating amount cannot be avoided.

According to the present invention, a membrane electrode assembly for a polymer electrolyte fuel cell in which the reaction efficiency is improved by eliminating the non-uniformity of the current density in the plane of the membrane electrode assembly is manufactured by a simple method. The purpose is to provide a method.

[0012]

Therefore, the present invention (Claim 1) includes a polymer electrolyte membrane and a catalyst layer disposed adjacent to the polymer electrolyte membrane, and the catalyst layer is interposed between the polymer electrolyte membrane and the catalyst layer. Membrane electrode assembly for a polymer electrolyte fuel cell, comprising a cathode and an anode facing each other, and forming a catalyst layer of at least one of the cathode and the anode using a coating liquid containing a catalyst and an ion exchange resin. In the manufacturing method, a die having an inlet for introducing the coating liquid and a linear outlet from which the coating liquid is discharged is used, and the die is the linear outlet from the inlet. Has a partition wall for partitioning into a plurality of sections, and the partitioning direction of the partition wall is inclined with respect to the direction in which the coating base material facing the linear outlet moves relative to the die. Multiple coating liquids having different compositions from each other. The coating substrate is introduced from the injection port so as not to mix with each other and goes toward the linear outlet through the different compartments, respectively, and the coating substrate is moved by moving at least one of the die and the coating substrate. At least one of the catalyst layers by relatively moving in a direction substantially perpendicular to the longitudinal direction of the linear outlet and applying the coating liquid on the coating substrate to form the catalyst layer. The part is formed so that the composition continuously changes in the longitudinal direction of the linear outlet of the die by the distribution of the plurality of coating liquids.

Since the guide partition is provided at the entrance of the die, a plurality of coating liquids are introduced without being mixed with each other in accordance with the partition partitioned by the guide partition, and the plurality of coating liquids are introduced. The sections are guided along the laminar streamline while maintaining a corresponding relationship between the sections to reach the linear outlet.

Since the guide partition wall divides the injection port by inclining with respect to the direction in which the coating substrate moves relative to the die, a plurality of coating liquids are applied at the linear outlet. Are inclined and distributed with respect to the direction in which they move relative to the die. The plurality of coating liquids that have been distributed in an inclined manner are applied onto the coating base material from the linear outlet by the relative movement of the coating base material with respect to the die. A coating film is formed in which the liquid is inclined and overlapped in the thickness direction of the coating film in correspondence with the partition formed by the guide partition.

Therefore, according to the method of manufacturing a membrane electrode assembly for a polymer electrolyte fuel cell of the present invention, the catalyst layer of the membrane electrode assembly for a polymer electrolyte fuel cell is fed to the catalyst layer in the flowing direction ( Hereinafter, the composition thereof can be continuously changed along with the gas flow). Therefore, it is possible to manufacture a membrane electrode assembly for a polymer electrolyte fuel cell capable of ensuring an efficient cell reaction over the entire surface regardless of the upstream and downstream of the gas flow.

There may be a plurality of injection ports. In this case, each injection port communicates with a plurality of different compartments partitioned by a guide partition, and the coating liquid is introduced from each different injection port. You may. Further, there may be a plurality of linear outlets depending on the number of coating liquids.

In the present invention (claim 2), it is preferable that the thickness of the catalyst layer is made uniform by using the above method.

If the thickness of the catalyst layer is not uniform, when a gas diffusion layer made of carbon cloth or carbon paper is arranged adjacent to the catalyst layer, the adhesion between the catalyst layer and the gas diffusion layer becomes insufficient. Cheap. Further, in the portion where the thickness of the catalyst layer becomes thicker, the diffusion of the reaction gas to the electrode reaction surface becomes worse,
The fuel cell characteristics may deteriorate. According to the above method, the thickness can be uniform even if the composition of the catalyst layer changes continuously in the plane.

Furthermore, the present invention (claim 3) is directed to a cathode and an anode having a polymer electrolyte membrane and a catalyst layer disposed adjacent to the polymer electrolyte membrane and facing each other through the polymer electrolyte belly. A method for producing a membrane electrode assembly for a polymer electrolyte fuel cell, comprising: forming the polymer electrolyte membrane using a coating liquid containing an ion exchange resin, for introducing the coating liquid. Using a die having a linear inlet from which the inlet and the coating liquid are discharged, the die has a guide partition that divides into a plurality of sections from the inlet toward the linear outlet, The partitioning direction of the guide partition is inclined with respect to the direction in which the coating base material facing the linear outlet moves relative to the die, and a plurality of coating liquids having different compositions are mixed with each other. It is introduced from the inlet so that it does not match By moving at least one of the die and the coating substrate toward the linear outlet through the plurality of compartments, the coating substrate is relatively moved in a direction substantially perpendicular to the longitudinal direction of the linear outlet. By moving the coating solution onto the coating substrate to form the polymer electrolyte membrane, at least a part of the polymer electrolyte membrane is distributed among the plurality of coating solutions. Is formed so that the composition continuously changes in the longitudinal direction of the linear outlet of the die.

The method for producing a membrane electrode assembly for a polymer electrolyte fuel cell of the present invention comprises a polymer electrolyte membrane of a membrane electrode assembly for a polymer electrolyte fuel cell, the composition of which is continuously changed along a gas flow. Can be changed. Therefore, it is possible to manufacture a membrane electrode assembly for a polymer electrolyte fuel cell capable of ensuring an efficient cell reaction over the entire area of the surface regardless of the upstream and downstream of the gas flow by a simple operation. Further, similarly to the case of the catalyst layer, the thickness of the polymer electrolyte membrane can be made uniform by this method even if the composition continuously changes in the plane.

Further, in the present invention (claim 4), the inside of the injection port is partitioned into two compartments by one guide partition, and two kinds of coating liquids are respectively injected from the different compartments. It is characterized by

By this, the injection port can be simply constructed.

Further, according to the present invention (claim 5), the injection port is arranged so that the boundary line between the distribution sections of the two types of coating liquids at the linear outlet is one diagonal position of the linear outlet. In the above, the guide partition walls are arranged at corresponding diagonal positions.

With this, the linear outlet can be simply constructed. Further, the compositions of the two kinds of coating liquids can be made to have a linear inclination characteristic and continuously change over the entire longitudinal direction of the linear outlet.

Furthermore, the present invention (claim 6) is characterized in that the inlet is rectangular, circular or elliptical, and the guide partition wall is disposed diagonally across the inlet. To do.

As a result, it is possible to select the shape of the injection port which can be easily processed in the die manufacturing.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In the method of the present invention, the catalyst layer or the polymer electrolyte membrane of the membrane electrode assembly for polymer electrolyte fuel cells is produced by coating. Hereinafter, the catalyst layer or the polymer electrolyte membrane produced by the coating method of the present invention will be referred to as a coating membrane for description. FIG. 1 shows a die used in this coating film manufacturing method in a plan view (a), a front view (b), and a sectional view taken along the line I-I (b) of FIG.
Indicated by.

1A to 1C, a coating die 1 has an injection port 3 for injecting a plurality of types (two types in the figure) of coating liquids A and B having different compositions. In addition, a linear outlet 7 that opens in a slit shape is provided at the lower end through an expansion portion 5 that expands and guides the coating liquids A and B from the inlet 3 along the laminar streamline in a divergent manner. .

The die 1 is provided with a guide partition wall 9 for partitioning the plural kinds of coating liquids A and B from each other so that the plural kinds of coating liquids A and B are distributed and delivered to a required section at the linear outlet 7. Prepare The guide partition 9 partitions the inside of the injection port 3 and is formed at least in a range up to the expanded portion 5 and, if necessary, in a range extending from the injection port 3 to the linear outlet 7.

The guide partition 9 has a direction X in which the boundary line L of the distribution section at the linear outlet 7 moves the die 1 relative to the coating substrate (direction perpendicular to the longitudinal direction of the linear outlet 7). It is arranged to be inclined with respect to. For example, in the case where one diagonal position of the linear outlet 7 is the boundary line L of the distribution section,
The guide partition wall 9 is arranged at a position corresponding to the distribution section of the linear outlets 7 via the laminar flow line, that is, at a corresponding diagonal position at the injection port 3.

Next, the processing operation of the above coating film manufacturing method will be described. In the die 1 having the above-described configuration, the plurality of types of coating liquids A and B are simultaneously injected from the ports (not shown) by dividing the injection port 3 into each section divided by the guide partition wall 9.

The guide partition 9 guides the plurality of types of injected coating liquids A and B to the expanding portion 5 while avoiding mutual mixing. The coating liquids A and B are guided along the laminar streamline in the expanding portion 5 toward the linear outlet 7. At this time, the coating liquids A and B are sent to the linear outlet 7 while maintaining the mutual correspondence defined by the guide partition wall 9.

The coating of the film is performed by moving the die 1 relative to a coating substrate (not shown) in the front direction X (direction orthogonal to the width direction of the expanding die 1) (usually the die is used). 1 is fixed and the coated substrate is moved). By this operation, a coating film having an internal structure corresponding to the distribution section of the linear outlets 7 is formed.

That is, since the boundary line L of the distribution section at the linear outlet 7 is inclined with respect to the direction X in the above operation, the coating liquids A and B are superposed by the above operation and in the thickness direction. On the other hand, a coating film having an internal structure whose composition is inclined is formed.

Next, the coating film formed by the coating film manufacturing method of the present invention will be described. A coating film formed by the coating film manufacturing method of the present invention is shown in a plan view (a) of FIG. 2 and a sectional view (b) taken along the line II-II.

In FIGS. 2 (a) and 2 (b), the coating film 11 formed by the above-described manufacturing method is arbitrary at right angles to the direction X in which the die 1 is moved relative to the coating substrate. In the cross section of the coating liquids A and B, the linear outlet 7 of the die 1
Is formed corresponding to the distribution section of. Therefore, the coating film 11 is configured by the coating liquids A and B being inclined and overlapped by the boundary line M which is inclined with respect to the thickness direction.

This coating film 11 has two types of coating liquids A and B.
Are vertically overlapped with each other, and the boundary line M is inclined along the diagonal line of the cross section. That is, two types of coating liquids A for coating films,
In B, one coating liquid A occupies the entire thickness T of the coating film at one end (the right end in the figure) of the cross section, and the other coating liquid B forms the coating film T at the other end (the left end in the figure). It occupies the entire thickness T, and in the middle portion of the width W of the coating film 11, the layers are inclined and superimposed with the thickness distribution according to the position.

Thus, the thickness of one coating liquid A gradually decreases from one end of the cross section, and conversely, the thickness of the other coating liquid B gradually increases from one end of the cross section. The composition of the coating film 11 continuously changes in the direction of its transverse line. From this, the coating film 11 exhibits a tilt characteristic in which the characteristics continuously change in the transverse line direction corresponding to the composition change.

Specifically, regarding the characteristics of the coating film 11, the characteristics of one coating solution A occupy one end of the cross section (the right end in the figure), and the other end (the left end in the figure) of the other. The characteristics of the coating liquid B dominate, and the characteristics at the intermediate position correspond to the distribution of the two types of coating liquids A and B.

Membrane electrode assembly 10 of polymer electrolyte fuel cell
In the production of No. 1, the polymer electrolyte membrane 103 and / or the catalyst layer 105a of the anode and / or the catalyst layer 105b of the cathode are coated films having the above-mentioned gradient characteristics.

Specifically, since the reaction conditions gradually change along the flow path of the reaction gas acting on the membrane electrode assembly 101, it is necessary to provide the inclination characteristics in response to the change in the reaction conditions. Polymer electrolyte membrane 103, catalyst layer 105
At least one of a and 105b is cast-formed.

As described above, since the reaction environment corresponding to the change in conditions can be secured by the inclination characteristics of the polymer electrolyte membrane 103 or the catalyst layers 105a and 105b, the current density is uniform throughout the entire process of the gas flow path. Thus, a highly efficient battery reaction can be secured. Therefore, the reaction efficiency of the entire membrane electrode assembly 101 can be improved by the manufacturing method of the present invention.

Next, another example of the gradient distribution of the coating film will be described. FIGS. 3A to 3D show examples of arrangement of the guide partition walls of the injection port 3. 3, in each case, the guide partition walls 9, 9a, 9b are configured to be inclined with respect to the direction X (the vertical direction in the drawing) that moves relative to the coating base material of the die 1.

The guide partition 9 shown in FIG. 3A is an example in which a part of the rectangular inlet 3 in the width direction is diagonally crossed.
The coating liquids A and B are inclined and overlapped in a part in the width direction of the coating film in a distribution corresponding to the partition partitioned by the guide partition wall 9.

The guide partitions 9a and 9b in FIG. 3 (b) are an example in which the width direction of the injection port 3 is divided into two and diagonally crossed. The coating liquids A and B are inclined and overlapped in one half of the width direction of the coating film, and the coating liquids B and C are inclined and overlapped in the other half of the width direction of the coating film.

The guide partitions 9a and 9b shown in FIG. 3 (c) are examples in which each of the guide partitions 9a and 9b is obliquely arranged across different portions of the injection port 3 in the width direction. The coating liquids A, B, and C partially overlap with each other in three layers and also overlap each other with an inclination.

The guide partition wall 9 in FIG. 3D is an example in which the guide partition wall 9 is arranged diagonally across the circular inlet 3a. By making the inlet 3a rotatable, the inclination angle can be arbitrarily selected according to the inclination superposition of the coating liquids A and B. Further, the injection port 3a may be elliptical.

The coating film is formed by the die 1 having the injection ports 3 and 3a in a distribution corresponding to the partition structure. In this coating film, since the guide partition walls 9, 9a and 9b are all inclined with respect to the casting direction X of the die 1 (vertical direction in the drawing), the coating liquids A, B and C are superposed on each other. , The inclination characteristic according to the constitution of the coating film can be obtained.

In the above description of the coating film 11,
Since the two types of coating liquids A and B are in contact with each other at the boundary line M, they can permeate and diffuse between each other, and the composition can be continuously changed in a so-called blurring state (a state where the boundary line M is unclear). it can. The degree of this blur-like permeation diffusion is determined by the composition of the coating liquids A and B, the length of the guide partition 9 and other permeation diffusion conditions.

In particular, with respect to the selection of the range of the guide partition wall 9, the coating liquid A can be selected by appropriately selecting the condition that the injection port 3 is included in the range from the injection port 3 of the die 1 to the linear outlet 7. , B can be adjusted to the extent of osmotic diffusion in the extrusion stage until reaching the coated substrate.

Further, there may be two injection ports 3, and in this case, each injection port 3 communicates with two different compartments partitioned by the guide partition 9, and the coating liquids A and B are
It can be introduced from different inlets 3. Similarly, if there are three or more types of coating liquid, three or more injection ports 3
Also good. Further, there may be a plurality of linear outlets 7 depending on the number of coating liquids.

In the present invention, the catalyst layers 105a, 105b
And / or the ion exchange resin constituting the polymer electrolyte membrane 103 is preferably a fluorinated polymer having a sulfonic acid group, and particularly preferably a perfluorocarbon polymer having a sulfonic acid group.

The catalyst contained in the catalyst layers 105a and 105b is preferably platinum, a platinum group metal or an alloy thereof. The dispersion medium contained in the coating liquid is not particularly limited, but those capable of favorably dispersing the ion exchange resin and the catalyst are preferable, and examples thereof include alcohols and ethers.

The membrane electrode assembly 101 for a polymer electrolyte fuel cell obtained by the manufacturing method of the present invention has the following effects, for example. In the polymer electrolyte fuel cell, a gas containing hydrogen is supplied to the anode and a gas containing oxygen is supplied to the cathode, but hydrogen and oxygen are consumed by the reaction and water is produced at the cathode.

Therefore, the concentrations of hydrogen and oxygen gases continuously and gradually decrease from the gas inlet to the outlet, and when the gas is not supplied in a saturated state by steam at the cathode, the gas inlet to the outlet. The generated water continuously and gradually increases the amount of water in the gas.

According to the method of the present invention, the catalyst layers 105a, 10a and 10b are changed according to the continuous changes in the reaction gas concentration and the water content.
5b or the in-plane composition of the polymer electrolyte membrane 103 can be continuously changed, and as a result, the reaction can be carried out more uniformly in the plane. By doing so, water management, temperature management, etc. become more appropriate, and the reaction efficiency can be improved.

A specific example will be described below. For example, when hydrogen gas reformed from a hydrocarbon-based gas is supplied to the anode as a fuel gas, CO is usually contained in the gas, but the concentration ratio of CO in the supplied gas and the concentration of hydrogen gas are The hydrogen gas is consumed by the electrochemical reaction on the catalyst and decreases, so that the fuel gas changes continuously from the inlet to the outlet.

Here, for example, when platinum and a platinum ruthenium alloy are used for the catalyst of the anode, platinum is formed in the plane of the anode catalyst layer 105a from the gas inlet to the gas outlet in accordance with the concentration ratio of the CO concentration and the hydrogen gas. By continuously changing the ratio of the platinum-ruthenium alloy, poisoning by CO can be efficiently suppressed in the entire surface of the membrane electrode assembly 101. As a result, the efficiency of the electrochemical reaction can be increased.

Further, since water is produced by the reaction at the cathode, when the gas to be supplied is not humidified and supplied in a saturated state at an operating temperature or higher, the water content in the gas gradually increases from the gas inlet to the gas outlet. Increase. Therefore,
If the mixing ratio of the resin having a high ion exchange capacity and the resin having a low ion exchange capacity is continuously changed so that many ion exchange resins having a high water content (high ion exchange capacity) are arranged near the inlet rather than the gas outlet. The reaction sites can be increased in the entire surface of the membrane electrode assembly 101, and high output can be obtained.

[0060]

EXAMPLES The present invention will be described below with reference to examples. Example in which the cathode catalyst layer was continuously graded (Example 1), Example in which the polymer electrolyte membrane was graded (Example 2), and Example using a conventional coating method (Comparative Example 1) For each of the three types of membrane electrode assemblies 101, the current densities at the positions corresponding to the upstream, midstream, and downstream of the gas flow channel were measured.

The current density is low (0.2 A / cm ² )
For two levels of high density and high density (0.5 A / cm ² ), the initial output voltage and the anode side electrode were electrically set to 3
It was measured by a cell configuration divided into one (upstream, midstream, and downstream from the cell inlet side). The results are shown in Table 1.

Example 1 Based on tetrafluoroethylene
Polymerization unit and CF₂= CF-OCF₂CF (CF ₃) O
(CF₂)₂SO₃Ions composed of polymerized units based on H
Copolymerization with exchange capacity of 1.10 meq / g dry resin
(Hereinafter referred to as "copolymer A") and platinum ruthenium compound
Gold (platinum: ruthenium: 4: 6 molar ratio) supported carbon
(Carbon: alloy is 1: 1 by mass ratio) and 5: 9 mass
Concentration of solid content contained in the ratio and dissolved or dispersed in ethanol
A 10% by mass liquid was prepared. This is called "anode catalyst layer type"
A working dispersion ".

A dispersion liquid containing copolymer A and platinum-supporting carbon (platinum: carbon in a mass ratio of 1: 1) in a mass ratio of 1: 2, and having ethanol as a dispersion medium and a solid content concentration of 13.7 mass%. Was produced. This is designated as "cathode catalyst layer forming dispersion liquid 1".

Further, a copolymer having an ion exchange capacity of 1.33 meq / g dry resin (hereinafter referred to as "copolymer B") was used in the same manner as the above-mentioned copolymer A. A dispersion liquid containing polymer B and platinum-supporting carbon (platinum: carbon in a mass ratio of 1: 1) in a mass ratio of 1: 2 and having ethanol as a dispersion medium and a solid content concentration of 14.5 mass% was prepared. This is designated as "cathode catalyst layer forming dispersion 2".

Next, the anode catalyst layer forming dispersion was coated with platinum ruthenium (0.50 mg / cm ² ) on one surface of a coated substrate made of a polypropylene (hereinafter referred to as PP) film having a thickness of 50 μm. The anode catalyst layer 1 by applying a die coating method so that
05a was formed.

The cathode catalyst layer 105b is composed of a dispersion liquid 1 for forming a cathode catalyst layer and a dispersion liquid 2 for forming a cathode catalyst layer.
An inlet 3 for introducing two kinds of coating liquid from two ports,
It was formed using a die 1 with linear outlets 7 through which they are discharged. The die 1 is, as shown in FIG.
From the pouring port 3 to the linear outlet 7, there is a guide partition 9 that is inclined so that the two types of coating liquids flowing in the die 1 overlap at the contact portion in the thickness direction of the linear outlet 7.

Using this die 1, one side of a coating substrate made of a PP film having a thickness of 50 μm was coated so that the two types of coating liquids were continuously unevenly distributed (platinum adhesion amount was 0. Four
0 mg / cm ² ). The coated film was dried to form the cathode catalyst layer 105b.

The PP film having the cathode catalyst layer 105b obtained above formed on one surface and the anode catalyst layer 105
The PP film having a formed on one side is made to face with the surface on which the catalyst layer is formed facing inward, and an ion exchange membrane (trade name: Flemion HR, manufactured by Asahi Glass Co., Ltd., ion exchange capacity: 1 .1 meq / g dry resin, dry film thickness 30
(μm) was sandwiched as the polymer electrolyte membrane 103, and hot pressing was performed.

The hot press conditions are 130 ° C. and 3 MPa.
For 4 minutes. After hot pressing, the PP film was peeled from the catalyst layers 105a and 105b for both the cathode and the anode to transfer these catalyst layers to the membrane, to obtain a membrane electrode assembly 101 composed of the catalyst layer and the ion exchange membrane.

The membrane electrode assembly 101 obtained by the above method was cut out so as to have an effective electrode area of 25 cm ^2, and incorporated into a battery performance measuring cell. Regarding this cell for battery performance measurement, hydrogen gas was supplied to the anode and air was supplied to the cathode, and the cell temperature was 80 ° C. and the anode humidification temperature was 75.
A power generation test was conducted at a temperature of 50 ° C. and a cathode humidification temperature of 50 ° C. Regarding the inclination direction of the cathode catalyst layer 105b, the portion coated with the cathode catalyst layer forming dispersion 2 in a large amount was arranged on the air inlet side, and the portion coated with a small amount was arranged on the air outlet side.

(Example 2) For the production of the polymer electrolyte membrane 103, "ion exchange membrane forming coating liquid 1" containing 13.5% by mass of the copolymer A and ethanol as a solvent, and copolyester were used. Injection port 3 for introducing two kinds of coating liquids of "ion exchange membrane forming coating liquid 2" containing 13% by mass of combined B and using ethanol as a solvent, and lines for discharging them. The die 1 shown in FIG.

The die 1 is inclined so that the two types of coating liquids flowing in the die 1 from the inlet 3 to the linear outlet 7 overlap at the contact portion in the thickness direction of the linear outlet 7. It has a guide partition 9. Using this die 1, two types of coating liquids were coated on a PP film so that they were unevenly distributed continuously. The coated film was dried in an oven at 80 ° C. for 10 minutes and the PP film was peeled off to form a polymer electrolyte film 103 having a thickness of 30 μm.

Next, an anode catalyst layer 105a was formed with the same specifications as in Example 1. Further, the cathode catalyst layer-forming dispersion liquid (having the same specifications as the cathode catalyst layer-forming dispersion liquid 1 of Example 1) was applied to one side of a coating substrate made of a PP film having a thickness of 50 μm by a die coating method. (Platinum adhesion amount was 0.50 mg / cm ² ). The coated film was dried to form a cathode catalyst layer 105b having a uniform composition.

Cathode catalyst layer 105 obtained by the above method
PP film with b formed on one side and anode catalyst layer 1
The PP film on which 05a is formed is made to face with the surface on which the catalyst layer is formed facing inward, and sandwiched between them as the polymer electrolyte membrane 103 having a thickness of 30 μm manufactured in this example, and hot pressed. went. The hot press conditions were the same as in Example 1 to obtain a membrane electrode assembly 101.

The membrane electrode assembly 101 obtained above was subjected to a power generation test under the same specifications as in Example 1. In the tilt direction of the polymer electrolyte membrane 103, a portion where the copolymer B was unevenly distributed was arranged on the air inlet side.

Comparative Example 1 The cathode catalyst layer 105b having a uniform composition was prepared by using only the dispersion liquid 1 for forming the cathode catalyst layer.
A membrane electrode assembly 101 was produced in the same manner as in Example 1 except that the above was produced. Using this membrane electrode assembly 101, a power generation test was conducted under the same specifications as in Example 1. For each of the cells of Example 1, Example 2, and Comparative Example 1, 0.2 (A / cm
² ), the cell voltage at 0.5 (A / cm ² ) and the current densities near the upstream, midstream and downstream of the gas were measured. The results are shown in Table 1.

[0077]

[Table 1]

It can be seen from Table 1 that the cell densities of the examples are higher than those of the comparative example in the current densities in the upstream, middle and downstream of the gas flow, and the cell voltage is high. That is, the membrane electrode assembly 1
The cell voltage is high because the current density is made uniform in the plane of 01.

[0079]

As described above, according to the manufacturing method of the present invention, by supplying two or more kinds of coating solutions having different compositions to a die, a coating film whose composition continuously changes can be formed. It can be formed by one coating process.

Therefore, according to the manufacturing method of the present invention,
Since the current density distribution in the membrane electrode assembly is made uniform, high battery performance can be obtained by a simple method without increasing cost.

[Brief description of drawings]

FIG. 1 is a plan view (a), a front view (b), and a sectional view taken along line I-I (c) of a die used in the manufacturing method of the present invention.

FIG. 2 is a plan view (a) of a coating film formed by the manufacturing method of the present invention and a sectional view (b) taken along line II-II thereof.

FIG. 3 shows various arrangement examples of guide partition walls of an injection port according to the manufacturing method of the present invention (a) to (d).

FIG. 4 is a sectional view of a membrane electrode assembly of a polymer electrolyte fuel cell.

FIG. 5 is a configuration example 1 of a gas flow path of a separator.

FIG. 6 is a configuration example 2 of the gas flow path of the separator.

FIG. 7 is a perspective view showing a conventional cast film forming method.

[Explanation of symbols]

1 die 3, 3a inlet 5 Expansion section 7 linear exit 9, 9a, 9b Guide partition 11 Coating film 101 membrane electrode assembly 103 Polymer electrolyte membrane 105a, 105b Catalyst layer A, B, C coating liquid L, M boundary line T coating film thickness Width of W coating film X Die direction to move relative to the coated substrate

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Shimoda             1150 Hazawa-machi, Kanagawa-ku, Yokohama-shi, Kanagawa             Asahi Glass Co., Ltd. F-term (reference) 5H018 AA06 AS01 BB01 BB03 BB06                       BB08 EE03 EE05 EE18 HH03                 5H026 AA06 BB04 CC03 CX05 HH03

Claims (6)

[Claims] 1. A cathode and an anode comprising a polymer electrolyte membrane, and a cathode and an anode having a catalyst layer disposed adjacent to the polymer electrolyte membrane and facing each other with the polymer electrolyte membrane interposed therebetween. A method for producing a membrane electrode assembly for a polymer electrolyte fuel cell, wherein at least one of the catalyst layers is formed by using a coating liquid containing a catalyst and an ion exchange resin, for introducing the coating liquid. Using a die having an injection port and a linear outlet from which the coating liquid is discharged, the die having a guide partition wall that divides into a plurality of sections from the injection port toward the linear outlet. The partitioning direction of the guide partition is inclined with respect to the direction in which the coating base material facing the linear outlet moves relatively to the die, and a plurality of coating liquids having different compositions are mutually separated. Introduced through the inlet so that they do not mix Toward the linear outlet through the plurality of different sections, and moving at least one of the die and the coating substrate to move the coating substrate in a direction substantially perpendicular to the longitudinal direction of the linear outlet. By moving the coating liquid on the coating substrate to form the catalyst layer, at least a part of the catalyst layer is distributed by the plurality of coating liquids. A method for producing a membrane electrode assembly for a polymer electrolyte fuel cell, which is characterized in that the die is formed so that the composition continuously changes in the longitudinal direction of the linear outlet. 2. The method for producing a membrane electrode assembly for a polymer electrolyte fuel cell according to claim 1, wherein the catalyst layer is formed to have a uniform thickness. 3. A polymer electrolyte membrane comprising: a polymer electrolyte membrane; and a cathode and an anode having a catalyst layer disposed adjacent to the polymer electrolyte membrane and facing each other through the polymer electrolyte belly. A method for producing a membrane electrode assembly for a polymer electrolyte fuel cell, which comprises forming a coating liquid containing an ion-exchange resin, wherein an inlet for introducing the coating liquid and the coating liquid are discharged. Using a die having a linear outlet, the die has a guide partition for partitioning into a plurality of sections from the inlet to the linear outlet, the partitioning direction of the guide partition is the The coating substrate facing the linear outlet is inclined with respect to the direction in which it moves relative to the die, and is introduced from the injection port so that a plurality of coating liquids having different compositions do not mix with each other. The line passing through the different sections The coating substrate by moving at least one of the die and the coating substrate toward the linear outlet, thereby relatively moving the coating substrate in a direction substantially perpendicular to the longitudinal direction of the linear outlet. By forming the polymer electrolyte membrane by applying the coating liquid on a material, at least a part of the polymer electrolyte membrane, by the distribution of the plurality of coating liquids of the linear outlet of the die A method for producing a membrane electrode assembly for a polymer electrolyte fuel cell, which is characterized in that the composition is formed so as to continuously change in the longitudinal direction. 4. The injection port is internally divided into two compartments by one guide partition, and two kinds of coating liquids are respectively injected from the different compartments. Item 8. A method for producing a membrane electrode assembly for a polymer electrolyte fuel cell according to item. 5. The guide is provided at a position of a corresponding diagonal line in the inlet so that a boundary line between distribution sections of the two types of coating liquids at the linear outlet is one diagonal line position of the linear outlet. The method for producing a membrane electrode assembly for a polymer electrolyte fuel cell according to claim 4, wherein partition walls are arranged. 6. The membrane for a polymer electrolyte fuel cell according to claim 4, wherein the inlet has a rectangular shape, a circular shape, or an elliptical shape, and the guide partition wall is arranged diagonally across the inlet. Method for manufacturing electrode assembly.