Method for manufacturing a membrane electrode assembly and apparatus for manufacturing a membrane electrode assembly

Abstract

A manufacturing method and manufacturing apparatus are provided that are capable of manufacturing a membrane electrode assembly with improved performance. [Solution] The method for manufacturing a membrane electrode assembly includes a coating step of coating a catalyst ink 34 onto a first surface 12a of a polymer electrolyte membrane 12, and a drying step of drying the coated catalyst ink 34. The coating step is carried out while a second surface 12b of the polymer electrolyte membrane 12 opposite to the first surface 12a is in contact with a swelling solvent 32 that swells the polymer electrolyte membrane 12.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a membrane electrode assembly and an apparatus for manufacturing a membrane electrode assembly.

Background Art

[0002] In electrochemical cells such as fuel cells, water electrolyzers, and electrochemical hydrogen pumps, a membrane electrode assembly in which a catalyst layer (also called an electrode layer) is formed on the surface of a polymer electrolyte membrane is used.

[0003] For example, Japanese Unexamined Patent Application Publication No. 2014-67539 describes a method for manufacturing a membrane electrode assembly by applying a catalyst ink to the surface of a polymer electrolyte membrane.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] There is a demand for further performance improvement of the membrane electrode assembly used in an electrochemical cell.

[0006] The present disclosure aims to solve the above-described problems.

Means for Solving the Problems

[0007] A first aspect of the present disclosure includes a coating step of coating a catalyst ink on a first surface of a polymer electrolyte membrane, and a drying step of drying the coated catalyst ink, wherein the coating step is performed in a state where a second surface opposite to the first surface of the polymer electrolyte membrane is brought into contact with a swelling solvent that swells the polymer electrolyte membrane, and is a method for manufacturing a membrane electrode assembly.

[0008] A second aspect of the present disclosure is a manufacturing apparatus for a membrane electrode assembly, comprising: a solvent containment section for containing a swelling solvent; a frame-shaped jig provided above the solvent containment section for supporting the peripheral edge of the polymer electrolyte membrane and bringing the polymer electrolyte membrane into contact with the swelling solvent; a coating apparatus positioned above the polymer electrolyte membrane for coating the polymer electrolyte membrane with catalyst ink; and a drying apparatus for heating and drying the catalyst ink coated on the polymer electrolyte membrane, wherein the drying apparatus is positioned behind the coating apparatus in the direction of relative movement of the coating apparatus with respect to the polymer electrolyte membrane. [Effects of the Invention]

[0009] According to this disclosure, deformation due to swelling of the polymer electrolyte membrane is suppressed, which leads to further performance improvements for the membrane electrode assembly. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a cross-sectional view of the membrane electrode assembly. [Figure 2] Figure 2 is an explanatory diagram of a manufacturing apparatus for a film electrode assembly according to the first embodiment. [Figure 3] Figure 3 is an explanatory diagram showing the manufacturing apparatus for the film electrode assembly shown in Figure 2, viewed from above. [Figure 4] Figure 4 is a flowchart showing a method for manufacturing a film electrode assembly according to the first embodiment. [Figure 5] Figure 5 is an explanatory diagram of a manufacturing apparatus for a film electrode assembly according to the second embodiment. [Figure 6] Figure 6 is a photograph showing wrinkles that occur when the film electrode assembly of the comparative example is swollen. [Modes for carrying out the invention]

[0011] (First Embodiment) As shown in Figure 1, the membrane electrode assembly 10 manufactured by the method described in this embodiment comprises a polymer electrolyte membrane 12 and a catalyst layer 14 laminated on the polymer electrolyte membrane 12. The catalyst layer 14 is formed on the first surface 12a and the second surface 12b, which are the surfaces of the polymer electrolyte membrane 12. The polymer electrolyte membrane 12 is, for example, a cation exchange membrane having hydrogen ion conductivity or an anion exchange membrane having hydroxide ion conductivity. The thickness of the polymer electrolyte membrane 12 is appropriately selected in the range of 5 μm to 300 μm depending on the application.

[0012] The catalyst layer 14 is also called the electrode layer. The catalyst layer 14 is composed of a mixture containing carrier particles such as carbon and an ionomer. The carrier particles support fine particles of a catalyst, such as platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), or alloys thereof. The ionomer is an ion-conducting polymer that serves as a pathway for ions. The catalyst layer 14 is a porous material, with open pores formed between the carrier particles and the ion-conducting polymer. In this embodiment, a donut-shaped catalyst layer 14 (Figure 2) used in water electrolysis devices or electrochemical hydrogen pumps is described as an example, but the shape of the catalyst layer 14 is not limited to this. The shape of the catalyst layer 14 may also be rectangular, which is commonly used in fuel cells and the like.

[0013] The membrane electrode assembly 10 is sandwiched from the thickness direction by a pair of gas diffusion layers (not shown), and further sandwiched from the thickness direction by a pair of separators via the gas diffusion layers, thereby forming a single electrochemical cell.

[0014] For example, some electrochemical cells, such as electrochemical hydrogen pumps and water electrolyzers, are used in a higher water content state compared to fuel cells. Therefore, deformation due to swelling of the polymer electrolyte membrane 12 tends to occur during use of the electrochemical cell. To prevent such problems, the inventors of the present invention have investigated a process in which the membrane electrode assembly 10 is immersed in water to pre-swell before assembling the electrochemical cell.

[0015] However, as shown in FIG. 6, it was found that when the membrane electrode assembly 10A (comparative example) manufactured by the conventional manufacturing method was immersed in water, wrinkles occurred due to the difference in the expansion rate between the polymer electrolyte membrane and the catalyst layer.

[0016] Therefore, in the present embodiment, the manufacturing apparatus 16 for a membrane electrode assembly described below is used for manufacturing the membrane electrode assembly 10.

[0017] As shown in FIGS. 2 and 3, the manufacturing apparatus 16 for a membrane electrode assembly of the present embodiment includes a solvent storage unit 18, a frame-shaped jig 20, a metal mask 22, a coating device 24, a drying device 26, a pump 28, and a solvent heating device 30. The solvent storage unit 18 is a container having a predetermined depth, and its peripheral portion is surrounded by a side wall 18a. The solvent storage unit 18 is formed in a rectangular shape when viewed from above. The solvent storage unit 18 stores the swelling solvent 32 in the container surrounded by the side wall 18a. The upper part of the solvent storage unit 18 is open, and the liquid surface 32a of the swelling solvent 32 is exposed at the upper part of the solvent storage unit 18.

[0018] The swelling solvent 32 is a solvent that infiltrates into the polymer electrolyte membrane 12 and swells the polymer electrolyte membrane 12. As the swelling solvent 32, for example, water, alcohols, or a mixture thereof can be used. It is preferable that the boiling point of the swelling solvent 32 is equal to or higher than the boiling point (initial boiling point) of the solvent used in the catalyst ink 34 described later.

[0019] The pump 28 causes the swelling solvent 32 to flow inside the solvent storage unit 18. The pump 28 suppresses the generation of a locally high-temperature portion of the swelling solvent 32 due to the heating of the drying device 26 by circulating the swelling solvent 32. In the illustrated example, the pump 28 is disposed outside the solvent storage unit 18, but is not limited thereto, and the pump 28 may be disposed inside the solvent storage unit 18.

[0020] The solvent heating device 30 heats the swollen solvent 32 inside the solvent storage part 18 to a predetermined temperature higher than room temperature. The solvent heating device 30 heats the swollen solvent 32 to a temperature higher than, for example, the boiling point (initial boiling point) of the catalyst ink 34 and lower than the boiling point of the swollen solvent 32.

[0021] The frame-shaped jig 20 is disposed above the solvent storage part 18. The frame-shaped jig 20 is formed in a rectangular shape when viewed from above. The frame-shaped jig 20 is vertically divisible and sandwiches and holds the peripheral part of the polymer electrolyte membrane 12 and the peripheral part of the metal mask 22 from above and below. The frame-shaped jig 20 supports the polymer electrolyte membrane 12 in a non-wrinkled state with the first surface 12a of the polymer electrolyte membrane 12 facing upward and the second surface 12b facing downward. Inside the frame-shaped jig 20, the second surface 12b of the polymer electrolyte membrane 12 is exposed. When the frame-shaped jig 20 is attached to the solvent storage part 18, the second surface 12b of the polymer electrolyte membrane 12 contacts the liquid surface 32a of the swollen solvent 32.

[0022] Note that the shape of the frame-shaped jig 20 when viewed from above is not limited to a rectangular shape. The frame-shaped jig 20 may be configured to hold only two opposite sides of the polymer electrolyte membrane 12. Also, the shape of the frame-shaped jig 20 when viewed from above may be an annular shape.

[0023] The metal mask 22 is disposed so as to cover the first surface 12a of the polymer electrolyte membrane 12. The metal mask 22 is formed of a metal sheet having the same thickness as the thickness of the catalyst layer 14. The metal mask 22 is supported by the frame-shaped jig 20 together with the polymer electrolyte membrane 12. The metal mask 22 has an opening 22a formed in a predetermined shape. The first surface 12a of the polymer electrolyte membrane 12 is exposed in the opening 22a of the metal mask 22. The metal mask 22 enables the formation of the catalyst layer 14 having a predetermined shape through the opening 22a. Also, since the metal mask 22 is formed of a material having higher rigidity than the polymer electrolyte membrane 12, it prevents the liquid surface 32a of the swollen solvent 32 from rippling and blocks the deformation of the polymer electrolyte membrane 12.

[0024] Furthermore, if the thickness of the polymer electrolyte membrane 12 is, for example, about 100 μm, the polymer electrolyte membrane 12 itself has the effect of preventing the swelling solvent 32 from becoming wavy, so deformation due to the swelling solvent 32 can be suppressed even without attaching the metal mask 22. Therefore, the metal mask 22 may be omitted depending on the thickness of the polymer electrolyte membrane 12. In this case, a flexible mask made of a resin sheet or the like may be used. Alternatively, the polymer electrolyte membrane 12 may be attached to the frame-shaped jig 20 after being attached to the metal mask 22.

[0025] The coating device 24 includes an ink supply unit 36 ​​and a blade 38. The ink supply unit 36 ​​is positioned above the metal mask 22 and the polymer electrolyte membrane 12. The ink supply unit 36 ​​discharges catalyst ink 34 from above the polymer electrolyte membrane 12 toward the first surface 12a.

[0026] The catalyst ink 34 is a paste-like liquid containing carrier particles, an ionomer, and an ink solvent. The ink solvent may consist of, for example, alcohols such as ethanol, methanol, and propanol, or a mixed solvent of these alcohols and water. The ink solvent is selected from solvents having a volatility similar to or higher than that of the swelling solvent 32 in order to enable rapid drying. That is, the ink solvent may have the same composition as the swelling solvent 32. More preferably, the ink solvent is selected from solvents whose boiling point (initial boiling point) is lower than that of the swelling solvent 32.

[0027] The blade 38 is a plate-shaped member that slides while in contact with the upper surface 22b of the metal mask 22. The blade 38 spreads the catalyst ink 34 by sliding along the upper surface 22b of the metal mask 22 in a predetermined direction. The catalyst ink 34 spread by the blade 38 enters the opening 22a of the metal mask 22 and is applied to the first surface 12a of the polymer electrolyte membrane 12 exposed at the opening 22a. The blade 38 forms a layer of catalyst ink 34 with a thickness approximately the same as the thickness of the metal mask 22.

[0028] The drying device 26 is positioned above the polymer electrolyte membrane 12 and behind the blade 38 (coating device 24) in the direction of relative movement with respect to the polymer electrolyte membrane 12. The drying device 26 dries the applied catalyst ink 34 by applying a hot wire or hot air to it. Drying here means that at least a portion of the ink solvent contained in the catalyst ink 34 is evaporated, so that the catalyst ink 34 becomes a solid state that is substantially non-fluid, and does not necessarily mean that all of the ink solvent is evaporated and removed. When the film thickness of the polymer electrolyte membrane 12 is thin, the polymer electrolyte membrane 12 is prone to deformation due to the undulation of the swelling solvent 32. Therefore, in order to prevent the undulation of the swelling solvent 32, it is preferable that the drying device 26 applies only a hot wire to the catalyst ink 34 without blowing air.

[0029] The manufacturing apparatus 16 for the membrane electrode assembly according to this embodiment is configured as described above. The manufacturing method for the membrane electrode assembly 10 will now be described.

[0030] As shown in Figure 4, first, a catalyst ink preparation process (step S10) is performed. The catalyst ink 34 is prepared by kneading carrier particles, ionomer powder, and an ink solvent. The ink solvent used is, for example, a solvent mainly composed of alcohol with a small amount of water. The prepared catalyst ink 34 is then filled into the ink supply unit 36.

[0031] Next, a solvent supply step (step S20) is performed, in which a predetermined swelling solvent 32 is supplied to the solvent containment section 18. The swelling solvent 32 is, for example, water. The swelling solvent 32 is circulated by the pump 28 and heated to a predetermined temperature by the solvent heating device 30. By keeping the swelling solvent 32 flowing, it is possible to prevent the temperature of the polymer electrolyte membrane 12 from rising in the drying step described later, and to make the interface between the polymer electrolyte membrane 12 and the catalyst ink 34 uniform. Since the interface between the polymer electrolyte membrane 12 and the catalyst ink 34 affects the porous structure of the catalyst layer 14 after drying, maintaining the swelling solvent 32 in a flowing state contributes to the uniformity of the catalyst layer 14.

[0032] Next, a mounting step (step S30) is performed in which the polymer electrolyte membrane 12 is attached to the frame-shaped jig 20. If a metal mask 22 is used, a metal mask placement step is performed in the mounting step in which the metal mask 22 is placed on the first surface 12a of the polymer electrolyte membrane 12. The metal mask 22 is attached to the frame-shaped jig 20 together with the polymer electrolyte membrane 12.

[0033] Next, a swelling step (step S40) is performed in which the second surface 12b of the polymer electrolyte membrane 12 is brought into contact with the liquid surface 32a of the swelling solvent 32 (liquid). The swelling step is performed by placing the frame-shaped jig 20 on top of the solvent containment section 18. During the swelling step, the second surface 12b of the polymer electrolyte membrane 12 comes into contact with the swelling solvent 32, and the swelling solvent 32 permeates the polymer electrolyte membrane 12, causing the polymer electrolyte membrane 12 to swell. At this time, the first surface 12a is maintained in a dry state without any droplets of the swelling solvent 32 present.

[0034] Next, a coating step (step S50) is performed in which the catalyst ink 34 is applied to the first surface 12a of the polymer electrolyte membrane 12. The coating step is performed by discharging the catalyst ink 34 from the ink supply unit 36 ​​onto the upper surface 22b of the metal mask 22, and then moving the blade 38 in the direction of arrow A in Figure 2. As the blade 38 moves, the catalyst ink 34 is applied to the polymer electrolyte membrane 12 exposed at the opening 22a of the metal mask 22. The coating step is performed with the second surface 12b of the polymer electrolyte membrane 12 in contact with the swelling solvent 32. According to this embodiment, compared to the case in which the catalyst ink 34 is applied while the swelling of the polymer electrolyte membrane 12 is suppressed, the difference in expansion rates between the catalyst layer 14 and the polymer electrolyte membrane 12 is reduced, so that the occurrence of wrinkles in the polymer electrolyte membrane 12 and the occurrence of thin-walled portions in the catalyst layer 14 can be suppressed.

[0035] Subsequently, a drying process (step S60) is performed to dry the catalyst ink 34. The drying process is carried out by applying a heating element (or hot air if necessary) to the catalyst ink 34 from the drying apparatus 26 shown in Figure 2, thereby heating the catalyst ink 34. Drying by the drying apparatus 26 is performed while moving the drying apparatus 26 to follow the blades 38 of the coating apparatus 24. This eliminates the need to provide a separate dryer and its associated conveying device, making it possible to simplify and save space in the manufacturing apparatus 16. In addition, deformation of the polymer electrolyte membrane 12 due to factors such as vibration during conveying and handling is suppressed, thus improving the quality of the membrane electrode assembly 10.

[0036] Furthermore, the drying process is carried out with the second surface 12b of the polymer electrolyte membrane 12 in contact with the swelling solvent 32. Therefore, even if some of the swelling solvent 32 contained in the polymer electrolyte membrane 12 evaporates during the drying process, the swelling solvent 32 is quickly supplied from the second surface 12b side. As a result, the catalyst ink 34 can be dried while the polymer electrolyte membrane 12 remains swollen, and shrinkage of the polymer electrolyte membrane 12 during the drying process is suppressed.

[0037] As a result, a catalyst layer 14 is formed on the first surface 12a of the polymer electrolyte membrane 12. Subsequently, if necessary, another metal mask 22 may be placed on the first surface 12a of the polymer electrolyte membrane 12, and the second and subsequent layers of catalyst ink 34 may be applied and dried.

[0038] Furthermore, the catalyst layer 14 may also be formed on the second surface 12b of the polymer electrolyte membrane 12 based on the steps described with reference to Figure 4 (steps S10, S20, S30, S40, S50, S60). In this case, the application of the catalyst ink 34 to the second surface 12b of the polymer electrolyte membrane 12 and its drying are performed with the first surface 12a on which the catalyst layer 14 is formed in contact with the swelling solvent 32.

[0039] The step of forming the catalyst layer 14 on the second surface 12b of the polymer electrolyte membrane 12 may be carried out by transferring (attaching) a catalyst layer 14 that has been formed in advance into a predetermined shape to the second surface 12b of the polymer electrolyte membrane 12.

[0040] Through the above steps, a membrane electrode assembly 10 having a polymer electrolyte membrane 12 and a catalyst layer 14 is completed. The membrane electrode assembly 10 completed in this way may be supplied to the electrochemical cell assembly process with the polymer electrolyte membrane 12 still swollen.

[0041] (Second Embodiment) As shown in Figure 5, the membrane electrode assembly manufacturing apparatus 16A of this embodiment continuously applies and dries the catalyst ink 34 to the rolled polymer electrolyte membrane 12A. In the configuration of the membrane electrode assembly manufacturing apparatus 16A of this embodiment, components similar to those in the membrane electrode assembly manufacturing apparatus 16 described with reference to Figures 2 and 3 are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0042] As shown in Figure 5, the membrane electrode assembly manufacturing apparatus 16A includes a solvent containment unit 18, a coating device 24, a drying device 26, a pump 28, and a solvent heating device 30, in addition to a roll supply unit 40, a roll winding unit 42, and a second frame-shaped jig 20A. The configurations of the solvent containment unit 18, the coating device 24, the drying device 26, the pump 28, and the solvent heating device 30 are the same as the corresponding configurations of the membrane electrode assembly manufacturing apparatus 16 described with reference to Figures 2 and 3.

[0043] The roll supply unit 40 supplies the polymer electrolyte membrane 12A, wound into a roll, to the solvent containment unit 18. The roll winding unit 42 winds the polymer electrolyte membrane 12A, on which the catalyst layer 14 is formed, into a roll. The polymer electrolyte membrane 12A supplied from the roll supply unit 40 moves in the direction of arrow B through the solvent containment unit 18 and is wound up by the roll winding unit 42.

[0044] The second frame-shaped jig 20A comprises a first roller section 44 and a second roller section 46. The first roller section 44 is attached to one end of the solvent containment section 18, and the second roller section 46 is attached to the other end of the solvent containment section 18. The polymer electrolyte membrane 12A supplied from the roll supply section 40 enters the solvent containment section 18 via the first roller section 44 and is discharged from the solvent containment section 18 via the second roller section 46. The first roller section 44 and the second roller section 46 maintain the polymer electrolyte membrane 12A in a wrinkle-free state while bringing the second surface 12b of the polymer electrolyte membrane 12A into contact with the swelling solvent 32.

[0045] The coating device 24 coats the catalyst ink 34 onto the first surface 12a of the polymer electrolyte membrane 12A while the polymer electrolyte membrane 12A is in a state of continuous movement. The drying device 26 is positioned behind the coating device 24 in the direction of relative movement to the polymer electrolyte membrane 12A and dries the coated catalyst ink 34.

[0046] As the catalyst ink 34 dries, a catalyst layer 14 (electrode layer) is formed on the first surface 12a of the polymer electrolyte membrane 12A. The polymer electrolyte membrane 12A with the catalyst layer 14 formed on it passes through the second roller section 46 and is wound onto the roll winding section 42.

[0047] In this embodiment as well, the application of the catalyst ink 34 and the drying of the catalyst ink 34 are performed with the second surface 12b of the polymer electrolyte membrane 12A in contact with the swelling solvent 32.

[0048] Furthermore, the application and drying of the catalyst ink 34 to the second surface 12b can also be carried out in the same manner as described above, while the first surface 12a on which the catalyst layer 14 is formed is in contact with the swelling solvent 32. Note that the formation of the catalyst layer 14 on the second surface 12b may also be carried out by transferring (attaching) a separately formed catalyst.

[0049] This embodiment also provides the same effects as the first embodiment.

[0050] With regard to the above embodiments, the following additional information is disclosed.

[0051] (Note 1) The manufacturing method for the membrane electrode assembly (10) of the present disclosure comprises a coating step (step S50) of coating a catalyst ink (34) onto a first surface (12a) of a polymer electrolyte membrane (12, 12A), and a drying step (step S60) of drying the coated catalyst ink, wherein the coating step is performed with the second surface (12b) of the polymer electrolyte membrane, opposite to the first surface, in contact with a swelling solvent (32) that swells the polymer electrolyte membrane.

[0052] According to the method described above, the catalyst ink can be applied while maintaining the swollen state of the polymer electrolyte membrane, thereby suppressing the occurrence of wrinkles in the membrane electrode assembly and thinning of the catalyst layer when assembling the electrochemical cell.

[0053] (Note 2) The method for manufacturing a film electrode assembly as described in Appendix 1, wherein the boiling point of the swelling solvent may be higher than the boiling point of the ink solvent contained in the catalyst ink. This method allows the catalyst ink to be dried quickly.

[0054] (Note 3) The method for manufacturing a membrane electrode assembly as described in Appendix 1, wherein the swelling solvent may be heated water. This method can accelerate the drying of the catalyst ink.

[0055] (Note 4) The method for manufacturing a membrane electrode assembly as described in Appendix 1, wherein the swelling solvent may be kept in a fluid state. This method allows for the uniform temperature of the polymer electrolyte membrane and the uniform interface between the electrode ink and the polymer electrolyte membrane, thereby forming a homogeneous catalyst layer.

[0056] (Note 5) A method for manufacturing a membrane electrode assembly as described in Appendix 1, comprising a metal mask placement step in which a metal mask (22) is placed on the first surface of the polymer electrolyte membrane prior to the coating step, wherein in the coating step, the catalyst ink may be applied to the polymer electrolyte membrane through the opening (22a) of the metal mask. With this method, the mask can prevent the surface of the swelling solvent from becoming turbulent, and deformation of the polymer electrolyte membrane can be suppressed.

[0057] (Note 6) The method for manufacturing a membrane electrode assembly as described in Appendix 1, wherein in the drying step, the catalyst ink may be dried by heating the catalyst ink while the second surface of the polymer electrolyte membrane is in contact with the swelling solvent. This method prevents shrinkage of the polymer electrolyte membrane during the drying step.

[0058] (Note 7) A method for manufacturing a membrane electrode assembly as described in any one of Appendix 1 to 6, wherein the coating step is performed using a manufacturing apparatus (16, 16A) comprising: a solvent containment section (18) for containing the swelling solvent; a frame-shaped jig (20) provided above the solvent containment section and supporting the peripheral edge of the polymer electrolyte membrane while bringing the second surface of the polymer electrolyte membrane into contact with the swelling solvent; and a coating device (24) positioned above the polymer electrolyte membrane and coating the polymer electrolyte membrane with the catalyst ink. Prior to the coating step, a solvent supply step (step S20) for supplying the swelling solvent to the solvent containment section and a swelling step (step S40) for supporting the polymer electrolyte membrane with the frame-shaped jig and bringing the second surface of the polymer electrolyte membrane into contact with the swelling solvent may be performed. With this method, the shape of the polymer electrolyte membrane can be stabilized by the frame-shaped jig, making it possible to form a membrane electrode assembly with fewer irregularities.

[0059] (Note 8) A method for manufacturing a membrane electrode assembly as described in Appendix 7, wherein the manufacturing apparatus further comprises a drying apparatus (26) for heating and drying the catalyst ink coated on the first surface of the polymer electrolyte membrane, the drying apparatus being positioned behind the coating apparatus in the direction of relative movement of the coating apparatus with respect to the polymer electrolyte membrane, and the drying step may be performed by moving the drying apparatus relative to the polymer electrolyte membrane so as to follow the coating apparatus. With this method, since drying is performed immediately after the coating step, the equipment is simplified and variations in the quality of the membrane electrode assembly are suppressed.

[0060] (Note 9) The manufacturing apparatus (16, 16A) for a membrane electrode assembly according to the present disclosure comprises a solvent containment section (18) for containing a swelling solvent (32), a frame-shaped jig (20) provided above the solvent containment section and supporting the peripheral edge of the polymer electrolyte membrane (12, 12A) while bringing the polymer electrolyte membrane into contact with the swelling solvent, a coating apparatus (24) positioned above the polymer electrolyte membrane for coating the polymer electrolyte membrane with catalyst ink (34), and a drying apparatus (26) for heating and drying the catalyst ink coated on the polymer electrolyte membrane, wherein the drying apparatus is positioned behind the coating apparatus in the direction of relative movement of the coating apparatus with respect to the polymer electrolyte membrane.

[0061] With the above configuration, the catalyst ink can be applied while the polymer electrolyte membrane is swollen, thus suppressing the occurrence of wrinkles in the membrane electrode assembly and the formation of thin portions in the catalyst layer.

[0062] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above. [Explanation of Symbols]

[0063] 10, 10A...Membrane electrode assembly 12, 12A...Polymer electrolyte membrane 12a…First side 12b…Second side 16, 16A...Manufacturing equipment 18...Solvent containment section 20…Frame-shaped jig 22…Metal mask 22a...Opening 24...Coating device 26... Drying apparatus 32... Swelling solvent 34… Catalyst ink

Claims

1. A coating step in which a catalyst ink is applied to the first surface of a polymer electrolyte film, A drying step for drying the applied catalyst ink, It has, The coating step is performed with the second surface of the polymer electrolyte membrane, opposite to the first surface, in contact with a swelling solvent that causes the polymer electrolyte membrane to swell, in a method for manufacturing a membrane electrode assembly.

2. A method for manufacturing a membrane electrode assembly according to claim 1, A method for manufacturing a film electrode assembly, wherein the boiling point of the swelling solvent is higher than the boiling point of the ink solvent contained in the catalyst ink.

3. A method for manufacturing a membrane electrode assembly according to claim 1, wherein the swelling solvent is heated water.

4. A method for manufacturing a membrane electrode assembly according to claim 1, wherein the swelling solvent is kept in a fluid state.

5. A method for manufacturing a membrane electrode assembly according to claim 1, Prior to the coating step, the process includes a metal mask placement step in which a metal mask is placed on the first surface of the polymer electrolyte membrane. A method for manufacturing a membrane electrode assembly, wherein in the coating step, the catalyst ink is applied to the polymer electrolyte membrane through the openings of the metal mask.

6. A method for manufacturing a membrane electrode assembly according to claim 1, A method for manufacturing a membrane electrode assembly, wherein in the drying step, the catalyst ink is dried by heating the catalyst ink while the second surface of the polymer electrolyte membrane is in contact with the swelling solvent.

7. A method for manufacturing a membrane electrode assembly according to any one of claims 1 to 6, The aforementioned coating step is A solvent containment section for containing the swelling solvent, A frame-shaped jig provided on the solvent containment section, which supports the peripheral edge of the polymer electrolyte membrane and brings the second surface of the polymer electrolyte membrane into contact with the swelling solvent, The manufacturing process is carried out using a manufacturing apparatus comprising a coating device positioned above the polymer electrolyte membrane and used to coat the catalyst ink onto the polymer electrolyte membrane. Prior to the aforementioned coating process, A solvent supply step of supplying the swelling solvent to the solvent containment section, A method for manufacturing a membrane electrode assembly, comprising: supporting the polymer electrolyte membrane in the frame-shaped jig and performing a swelling step in which the second surface of the polymer electrolyte membrane is brought into contact with the swelling solvent.

8. A method for manufacturing a membrane electrode assembly according to claim 7, The manufacturing apparatus further includes a drying apparatus for heating and drying the catalyst ink applied to the first surface of the polymer electrolyte membrane. The drying apparatus is positioned behind the coating apparatus in the direction of relative movement of the coating apparatus with respect to the polymer electrolyte membrane. A method for manufacturing a membrane electrode assembly, wherein the drying step is performed by moving the drying apparatus relative to the polymer electrolyte membrane so as to follow the coating apparatus.

9. A solvent containment section for containing the swelling solvent, A frame-shaped jig is provided on the solvent containment section and supports the peripheral edge of the polymer electrolyte membrane while bringing the polymer electrolyte membrane into contact with the swelling solvent, A coating device is positioned above the polymer electrolyte membrane and applies catalyst ink to the polymer electrolyte membrane. The device comprises a drying apparatus for heating and drying the catalyst ink coated on the polymer electrolyte membrane, The drying apparatus is positioned behind the coating apparatus in the direction of relative movement of the coating apparatus with respect to the polymer electrolyte membrane, and is a device for manufacturing a membrane electrode assembly.

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