JP2020145011A - Manufacturing method of membrane electrode assembly with frame - Google Patents

Abstract

To provide a manufacturing method of a membrane electrode assembly with a frame capable of improving productivity while bubbles contained in an adhesive can easily come out.SOLUTION: A manufacturing method of a membrane electrode assembly 20 with a frame includes: a first width adhesive application step of applying an adhesive 22a having a first width W1 to an adhesive surface 17a of an electrolyte membrane 17; a second width adhesive application step of applying an adhesive 22b having a second width W2 smaller than the first width W1 at a center position of the adhesive 22a having the first width W1; and a frame arranging step of arranging a resin frame 21 on the adhesive 22b having the second width W2 to spread the adhesive 22a having the first width W1 and the adhesive 22b having the second width W2 on the adhesive surface 17a.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing a membrane electrode assembly with a frame.

The membrane electrode assembly with a frame used in a fuel cell includes a membrane electrode assembly having an electrolyte membrane and a frame-shaped resin frame arranged on the outer periphery of the membrane electrode assembly. As shown in Patent Document 1, for example, such a membrane electrode assembly with a frame is used in a coating step of applying an adhesive to an adhesive surface provided on an outer edge of an electrolyte film and on an adhesive surface to which the adhesive is applied. It is manufactured by an arrangement step of arranging a resin frame and a vibration process of vibrating an adhesive surface coated with an adhesive. In the vibration process, the adhesive can be spread uniformly on the adhesive surface by vibrating the adhesive surface to which the adhesive is applied, so that the adhesive strength and sealing property between the membrane electrode assembly and the resin frame are improved. be able to.

Japanese Unexamined Patent Publication No. 2015-115242

The applied adhesive often contains air bubbles. The presence of air bubbles in the adhesive affects the adhesive strength, sealing property, and the like, so removal of air bubbles is desired. However, in the above-mentioned manufacturing method, there is a problem that it is difficult to improve the productivity because the bubbles contained in the adhesive are difficult to escape and it takes time to remove the bubbles.

The present invention has been made to solve such a technical problem, and is a method for manufacturing a membrane electrode assembly with a frame, which can easily remove air bubbles contained in an adhesive and improve productivity. The purpose is to provide.

The method for producing a framed film electrode joint according to the present invention is to attach a film electrode joint having an electrolyte film and an adhesive surface provided on the outer periphery of the film electrode joint and provided on the outer edge of the electrolyte film. A method for manufacturing a film electrode joint with a frame including a resin frame to be adhered, wherein an adhesive having a first width is applied to the adhesive surface of the electrolyte film, and an adhesive application step having a first width. The second width adhesive application step of applying the second width adhesive smaller than the first width to the center position of the first width adhesive, and the first width adhesive and the second width are applied. It is characterized by including a frame arranging step of arranging the resin frame on the adhesive having a second width so as to spread the adhesive having the adhesive on the adhesive surface.

In the method for manufacturing a membrane electrode assembly with a frame according to the present invention, the adhesive coating step is divided into a first width adhesive coating step and a second width adhesive coating step, and the second width is the first. Since it is smaller than the width, the applied first width adhesive and the second width adhesive are stepped. Therefore, when the resin frame is arranged in the frame arrangement step, a gap is generated between the applied adhesive and the membrane electrode assembly, and between the applied adhesive and the resin frame. Then, due to the weight or pressure of the arranged resin frame, the adhesive having the first width and the adhesive having the second width spread on the adhesive surface, and the air bubbles contained in the adhesive are pushed out accordingly. It can be moved to the gap described above. Therefore, the bubbles contained in the adhesive can be easily removed, and the time required for removing the bubbles can be shortened, so that the productivity can be improved.

According to the present invention, air bubbles contained in the adhesive can be easily removed, and productivity can be improved.

It is a schematic cross-sectional view which shows the main part of the fuel cell which used the membrane electrode assembly with a frame. It is a process drawing which shows the manufacturing method of the membrane electrode assembly with a frame. It is a schematic cross-sectional view for demonstrating the manufacturing method of the membrane electrode assembly with a frame. It is a schematic cross-sectional view for demonstrating the maximum bubble size and the minimum seal width which concerns on Example. (A) is a diagram showing confirmation results of Examples and Comparative Examples for the maximum bubble size, and (b) is a diagram showing confirmation results of Examples and Comparative Examples for the minimum seal width.

Hereinafter, embodiments of a method for manufacturing a membrane electrode assembly with a frame will be described with reference to the drawings, but before that, the structure of a fuel cell in which the membrane electrode assembly with a frame is used will be briefly described with reference to FIG. To do.

FIG. 1 is a schematic cross-sectional view showing a main part of a fuel cell in which a membrane electrode assembly with a frame is used. As shown in FIG. 1, a plurality of fuel cell cells 10, which are basic units, are stacked on the fuel cell 1. The fuel cell 10 is a solid polymer fuel cell that generates an electromotive force by an electrochemical reaction between an oxidant gas (for example, air) and a fuel gas (for example, hydrogen gas). The fuel cell 10 has a rectangular plate-shaped MEGA (Membrane Electrode & Gas Diffusion Layer Assembly) 11 and a pair of separators (that is, an anode side separator 12 and a cathode side separator 13) that sandwich the MEGA 11. ), And a frame-shaped resin frame 21 arranged on the outer periphery of the MEGA 11 and sandwiched between a pair of separators.

The MEGA 11 is a combination of a MEA (Membrane Electrode Assembly) 14, an anode-side gas diffusion layer 15 and a cathode-side gas diffusion layer 16 arranged on both sides of the MEA 14. The MEA 14 is composed of an electrolyte membrane 17 and a pair of electrode catalyst layers (that is, an anode side electrode catalyst layer 18 and a cathode side electrode catalyst layer 19) joined so as to sandwich the electrolyte membrane 17.

The electrolyte membrane 17 is made of a proton conductive ion exchange membrane formed of a solid polymer material. The electrode catalyst layer is formed of, for example, a porous carbon material carrying a catalyst such as platinum. On the other hand, the gas diffusion layer is formed of a gas-permeable conductive member such as a carbon porous body such as carbon paper or carbon cloth, or a metal porous body such as a metal mesh or foamed metal.

The separator is formed of, for example, a carbon member such as dense carbon obtained by compressing carbon particles to make gas impermeable, or a metal member such as press-molded stainless steel or titanium steel. Although not shown, the anode-side separator 12 and the cathode-side separator 13 have a corrugated shape by alternately repeating concave portions and convex portions, respectively. A plurality of oxidant gas flow paths 13a along the surface of the cathode side gas diffusion layer 16 are formed by the recess of the cathode side separator 13 and the cathode side gas diffusion layer 16 of the MEGA 11. On the other hand, a plurality of fuel gas flow paths (not shown) along the surface of the anode side gas diffusion layer 15 are formed by the recess of the anode side separator 12 and the anode side gas diffusion layer 15 of the MEGA 11.

Further, a gasket 23 as an inter-cell sealing material is arranged between the adjacent fuel cell 10s. The gasket 23 is formed of rubber, a thermoplastic elastomer, or the like, and is press-fitted between the anode-side separator 12 and the cathode-side separator 13 of two adjacent fuel cell cells 10, and is press-fitted between the anode-side separator 12 and the cathode-side separator 12 adjacent to each other. The space between the separator 13 and the separator 13 is sealed.

The resin frame 21 has a rectangular frame shape, is arranged on the outer periphery of the MEGA 11 so as to surround the MEGA 11, and is adhered to an adhesive surface 17a provided on the outer edge of the electrolyte membrane 17. More specifically, the resin frame 21 has a frame main body 21a having substantially the same thickness as the MEGA 11, and a protruding portion 21b protruding from the frame main body 21a toward the MEGA 11 side and formed thinner than the frame main body 21a.

The adhesive surface 17a of the electrolyte membrane 17 is arranged on the outer edge of the electrolyte membrane 17 and is exposed from, for example, the anode-side electrode catalyst layer 18 and the anode-side gas diffusion layer 15. In the schematic cross-sectional view of FIG. 1, only the cross section of the adhesive surface 17a is drawn, but in reality, the adhesive surface 17a has a rectangular frame shape along the outer edge portion of the rectangular electrolyte membrane 17 so as to correspond to the frame-shaped resin frame 21. Is formed in. Then, the protruding portion 21b of the resin frame 21 is joined to the electrolyte film 17 by the layered adhesive 22 provided on the adhesive surface 17a in a state of facing the adhesive surface 17a formed on the outer edge portion of the electrolyte film 17. There is.

The resin frame 21 is made of a thermosetting resin such as epoxy or phenol, or a thermoplastic resin such as polypropylene or polyethylene. As the adhesive 22, a thermosetting adhesive resin such as silicone, polyisobutylene, epoxy, or urethane can be used, or an ultraviolet (UV) curable adhesive resin or the like can be used.

In the present embodiment, the MEGA 11 and the resin frame 21 constitute a membrane electrode assembly 20 with a frame. That is, the membrane electrode assembly 20 with a frame has a structure including a MEGA 11 and a resin frame 21 arranged on the outer periphery of the MEGA 11 and adhered to an adhesive surface 17a provided on the outer edge of the electrolyte membrane 17. There is.

Hereinafter, a method for manufacturing the membrane electrode assembly 20 with a frame will be described with reference to FIGS. 2 and 3. The method for manufacturing the film electrode joint 20 with a frame includes a preparatory step S1 for preparing the MEGA 11 and the resin frame 21, respectively, and an adhesive 22a having a first width W1 is applied to the adhesive surface 17a of the electrolyte film 17 of the MEGA 11. 1-width adhesive application step S2 and a second-width adhesive application step of applying an adhesive 22b having a second width W2 smaller than the first width W1 to the center position of the adhesive 22a having the first width W1. It includes S3, a frame arranging step S4 for arranging the resin frame 21 on the adhesive 22b having a second width W2, and a curing step S5 for curing the adhesive.

First, in the preparation step S1, a MEGA 11 having an electrolyte membrane 17 having an adhesive surface 17a formed on an outer edge portion and a resin frame 21 having a protruding portion 21b are produced.

In the first width adhesive application step S2 following the preparation step S1, the adhesive 22a having the first width W1 is applied to a predetermined position on the adhesive surface 17a of the MEGA 11 (see FIG. 3A). The coating operation is performed along the frame-shaped adhesive surface 17a by, for example, screen printing. The "width" here means a length along the width direction of the adhesive surface 17a. The first width W1 is smaller than the width of the adhesive surface 17a.

In the second width adhesive application step S3 following the first width adhesive application step S2, the adhesive 22b having the second width W2 is applied to the center position of the applied adhesive 22a having the first width W1. The application work of the adhesive 22b having the second width W2 is also performed by screen printing. The second width W2 is smaller than the first width W1. As a result, on the adhesive surface 17a, the applied adhesive 22a having the first width W1 and the adhesive 22b having the second width W2 are stepped (see FIG. 3B).

In the frame arrangement step S4 following the adhesive application step S3 of the second width, the resin frame 21 produced in the preparation step S1 has a second width W2 so that the protruding portion 21b faces the adhesive surface 17a of the MEGA 11. It is placed on the adhesive 22b (see FIG. 3C). Next, the weight or pressure of the resin frame 21 pushes the adhesive 22a having the first width W1 and the adhesive 22b having the second width W2 onto the adhesive surface 17a. As a result, the stepped adhesive 22a and the adhesive 22b are pressed and spread so as to spread over the entire surface of the adhesive surface 17a. Along with this, the air bubbles contained in the adhesive 22a and the adhesive 22b are pushed out and moved to the gap between the MEGA 11 or the resin frame 21 (see the arrow in FIG. 3C).

In the curing step S5 following the frame arrangement step S4, the adhesive 22a and the adhesive 22b are cured. When a thermosetting adhesive resin is used for the adhesive 22a and the adhesive 22b, the adhesive 22a and the adhesive 22b may be cured by heating, and when an ultraviolet curable adhesive resin is used, it is cured by ultraviolet irradiation. Just do it. As a result, the membrane electrode assembly 20 with a frame is manufactured.

In the method for manufacturing the membrane electrode assembly 20 with a frame according to the present embodiment, the adhesive coating step is divided into a first width adhesive coating step S2 and a second width adhesive coating step S3, and the second Since the width W2 is smaller than the first width W1, the applied adhesive 22a of the first width W1 and the adhesive 22b of the second width W2 are stepped. Therefore, when the resin frame 21 is arranged in the frame arrangement step S4, gaps are formed between the applied adhesives 22a and 22b and MEGA11, and between the adhesives 22a and 22b and the resin frame 21, respectively.

Then, due to the weight or pressure of the arranged resin frame 21, the adhesive 22a having the first width W1 and the adhesive 22b having the second width W2 spread on the adhesive surface 17a, and the adhesives 22a and 22b are accompanied by this. The air bubbles contained in the above can be pushed out and moved to the above-mentioned gap. As a result, the bubbles contained in the adhesives 22a and 22b can be easily removed, and the time for removing the bubbles can be shortened, so that the productivity can be improved.

Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to the scope of the Examples.

<Example>
In the embodiment, the adhesive having the first width and the adhesive having the second width are sequentially applied on the electrolyte membrane of MEGA according to the above-mentioned manufacturing method, and then the resin frame is placed on the adhesive having the second width. A membrane electrode assembly with a frame was prepared by arranging. Further, the effect of removing air bubbles contained in the adhesive was confirmed on the prepared membrane electrode assembly 20 with a frame. The effect of removing air bubbles was confirmed by examining the maximum air bubble size and the minimum seal width shown in FIG. As shown in FIG. 4, the maximum bubble size is the sum of the bubble size A and the bubble size B, that is, the maximum bubble size = bubble size A + bubble size B. On the other hand, the minimum seal width = seal length − (bubble size A + bubble size B). The seal shown in FIG. 4 refers to an adhesive, and therefore the “seal length” shown in FIG. 4 is the thickness of the adhesive.

<Comparison example>
For comparison, a sample was prepared by applying the adhesive only once on the MEGA electrolyte membrane under the same conditions as in the example, and the prepared sample had the maximum bubble size and the minimum seal width as in the example. I examined.

The confirmation results of Examples and Comparative Examples are shown in FIG. As can be seen from FIG. 5, in the example, the maximum bubble size is reduced by about 0.8 mm (see FIG. 5 (a)) and the minimum seal width is about 0.9 mm (FIG. 5 (b)) as compared with the comparative example. )) It was an enlarged result. As a result, it was shown that according to the production method of the present invention, air bubbles contained in the adhesive can be easily removed, and air bubble removal can be improved.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs are designed without departing from the spirit of the present invention described in the claims. It is something that can be changed.

1 Fuel cell 10 Fuel cell cell 11 MEGA
12 Anode side separator 13 Cathode side separator 14 MEA
15 Anode side gas diffusion layer 16 Cathode side gas diffusion layer 17 Electrolyte film 17a Adhesive surface 18 Anode side electrode catalyst layer 19 Cathode side electrode catalyst layer 20 Membrane electrode assembly with frame 21 Resin frame 21a Frame body 21b Projection 22 Adhesive 23 gasket

Claims (1)

A framed membrane electrode assembly comprising a membrane electrode assembly having an electrolyte membrane and a resin frame arranged on the outer periphery of the membrane electrode assembly and adhered to an adhesive surface provided on an outer edge of the electrolyte membrane. It is a manufacturing method of
A first-width adhesive application step of applying an adhesive having a first width to the adhesive surface of the electrolyte membrane, and
A second width adhesive application step of applying an adhesive having a second width smaller than the first width to the center position of the adhesive having the first width,
A frame arranging step of arranging the resin frame on the adhesive having a second width so as to spread the adhesive having the first width and the adhesive having the second width on the adhesive surface.
A method for manufacturing a membrane electrode assembly with a frame, which comprises.

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