METHOD AND APPARATUS FOR PRODUCING 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 technology]

[0002] Electrochemical cells such as fuel cells, water electrolysis devices, and electrochemical hydrogen pumps use membrane electrode assemblies in which a catalyst layer (also called an electrode layer) is formed on the surface of a polymer electrolyte membrane.

[0003] For example, Japanese Patent Application Laid-Open No. 2014-67539 describes a method for producing 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] Japanese Patent Application Laid-Open No. 2014-67539 Summary of the Invention [Problem to be solved by the invention]

[0005] There is a demand for further improvements in the performance of membrane electrode assemblies used in electrochemical cells.

[0006] The present disclosure aims to solve the above-mentioned problems. [Means for solving the problem]

[0007] A first aspect of the present disclosure is a method for producing a membrane electrode assembly, comprising: a coating step of coating a catalyst ink onto 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 of the polymer electrolyte membrane opposite to the first surface is in contact with a swelling solvent that swells the polymer electrolyte membrane.

[0008] A second aspect of the present disclosure is an apparatus for manufacturing a membrane electrode assembly, comprising: a solvent storage unit that stores a swelling solvent; a frame-shaped jig that is provided above the solvent storage unit and that supports a peripheral portion of a polymer electrolyte membrane while bringing the polymer electrolyte membrane into contact with the swelling solvent; an applicator that is provided above the polymer electrolyte membrane and that applies a catalyst ink to the polymer electrolyte membrane; and a drying device that heats and dries the catalyst ink that has been applied to the polymer electrolyte membrane, wherein the drying device is provided behind the applicator in a direction of relative movement of the applicator with respect to the polymer electrolyte membrane. [Effects of the Invention]

[0009] According to the present disclosure, deformation due to swelling of the polymer electrolyte membrane is suppressed, thereby further improving the performance of the membrane electrode assembly. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view of a membrane electrode assembly. [Figure 2] FIG. 2 is an explanatory diagram of the manufacturing apparatus for the membrane electrode assembly according to the first embodiment. [Figure 3] FIG. 3 is an explanatory diagram showing the manufacturing apparatus for the membrane electrode assembly of FIG. 2 from above. [Figure 4] FIG. 4 is a flowchart showing a method for manufacturing a membrane electrode assembly according to the first embodiment. [Figure 5] FIG. 5 is an explanatory diagram of a manufacturing apparatus for a membrane electrode assembly according to the second embodiment. [Figure 6] FIG. 6 is a photograph showing wrinkles that occur when the membrane electrode assembly according to the comparative example is swollen. DETAILED DESCRIPTION OF THE INVENTION

[0011] (First embodiment) As shown in FIG. 1, a membrane electrode assembly 10 manufactured by the method described in this embodiment includes a polymer electrolyte membrane 12 and a catalyst layer 14 laminated on the polymer electrolyte membrane 12. The catalyst layers 14 are formed on a first surface 12a and a second surface 12b, which are 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 within a range of 5 μm to 300 μm depending on the application.

[0012] The catalyst layer 14 is also called an electrode layer. The catalyst layer 14 is composed of a mixture containing support particles such as carbon and an ionomer. The support particles support catalyst particles made of, for example, platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), or an alloy thereof. The ionomer is made of an ion-conductive polymer that serves as a passageway for ions. The catalyst layer 14 is porous, with open pores formed between the support particles and the ion-conductive polymer. Note that, in this embodiment, a donut-shaped catalyst layer 14 ( FIG. 2 ) used in a water electrolysis device or an electrochemical hydrogen pump will be described as an example, but the shape of the catalyst layer 14 is not limited thereto. The catalyst layer 14 may also have a rectangular shape, which is often used in fuel cells and the like.

[0013] The membrane electrode assembly 10 is sandwiched between a pair of gas diffusion layers (not shown) in the thickness direction, and further sandwiched between a pair of separators with the gas diffusion layers interposed therebetween, thereby forming one electrochemical cell.

[0014] For example, some electrochemical cells, such as electrochemical hydrogen pumps and water electrolysis devices, are used in a state with a higher water content than fuel cells. Therefore, the polymer electrolyte membrane 12 tends to swell and deform during use of the electrochemical cell. To prevent such problems, the inventors of the present application have investigated a process for assembling an electrochemical cell in which the membrane electrode assembly 10 is immersed in water to swell the membrane electrode assembly 10 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 expansion coefficient between the polymer electrolyte membrane and the catalyst layer.

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

[0017] 2 and 3, a membrane electrode assembly manufacturing apparatus 16 of this 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 sidewall 18a. The solvent storage unit 18 is formed in a rectangular shape when viewed from above. The solvent storage unit 18 stores a swelling solvent 32 in the container surrounded by the sidewall 18a. The top of the solvent storage unit 18 is open, and a liquid surface 32a of the swelling solvent 32 is exposed at the top of the solvent storage unit 18.

[0018] The swelling solvent 32 is a solvent that infiltrates the polymer electrolyte membrane 12 and swells the polymer electrolyte membrane 12. For example, water, alcohols, or mixtures of these can be used as the swelling solvent 32. The boiling point of the swelling solvent 32 is preferably equal to or higher than the boiling point (initial boiling point) of the solvent used in the catalyst ink 34 described below.

[0019] The pump 28 causes the swelling solvent 32 to flow inside the solvent storage unit 18. By circulating the swelling solvent 32, the pump 28 prevents the swelling solvent 32 from becoming locally hot due to heating by the drying device 26. In the illustrated example, the pump 28 is disposed outside the solvent storage unit 18, but this is not limiting and the pump 28 may be disposed inside the solvent storage unit 18.

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

[0021] The frame-shaped jig 20 is placed on the solvent storage section 18. The frame-shaped jig 20 is formed in a rectangular shape when viewed from above. The frame-shaped jig 20 can be separated vertically and holds the peripheral edge of the polymer electrolyte membrane 12 and the peripheral edge of the metal mask 22 by sandwiching them from above and below. The frame-shaped jig 20 supports the polymer electrolyte membrane 12 without wrinkles, with the first surface 12a of the polymer electrolyte membrane 12 facing upward and the second surface 12b facing downward. The second surface 12b of the polymer electrolyte membrane 12 is exposed inside the frame-shaped jig 20. When the frame-shaped jig 20 is attached to the solvent storage section 18, the second surface 12b of the polymer electrolyte membrane 12 comes into contact with the liquid surface 32a of the swelling solvent 32.

[0022] 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 opposing sides of the polymer electrolyte membrane 12. Furthermore, the frame-shaped jig 20 may have an annular shape when viewed from above.

[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 from a metal sheet having the same thickness as the catalyst layer 14. The metal mask 22, together with the polymer electrolyte membrane 12, is supported by a frame-shaped jig 20. The metal mask 22 has openings 22a formed in a predetermined shape. The first surface 12a of the polymer electrolyte membrane 12 is exposed through the openings 22a of the metal mask 22. The metal mask 22 enables the formation of the catalyst layer 14 in a predetermined shape through the openings 22a. Furthermore, because the metal mask 22 is formed from a material that is more rigid than the polymer electrolyte membrane 12, it prevents rippling of the liquid surface 32a of the swelling solvent 32 and prevents deformation of the polymer electrolyte membrane 12.

[0024] If the thickness of the polymer electrolyte membrane 12 is as thick as, for example, about 100 μm, the polymer electrolyte membrane 12 itself has the effect of preventing rippling of the swelling solvent 32, and deformation due to rippling of the swelling solvent 32 can be suppressed without the use of 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. Furthermore, the polymer electrolyte membrane 12 may be attached to the metal mask 22 and then attached to the frame-shaped jig 20.

[0025] The coating device 24 has an ink supply unit 36 ​​and a blade 38. The ink supply unit 36 ​​is disposed above the metal mask 22 and the polymer electrolyte membrane 12. The ink supply unit 36 ​​ejects 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 be composed of, for example, alcohols such as ethanol, methanol, and propanol, or a mixture of these alcohols with water. To enable rapid drying, the ink solvent is selected from solvents having the same level of volatility as the swelling solvent 32 or higher volatility than the swelling solvent 32. In other words, the ink solvent may have the same composition as the swelling solvent 32. More preferably, the ink solvent is selected from solvents having a boiling point (initial boiling point) lower than the boiling point of the swelling solvent 32.

[0027] The blade 38 is a plate-like member that slides while making 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 openings 22a of the metal mask 22 and is applied to the first surface 12a of the polymer electrolyte membrane 12 exposed in the openings 22a. The blade 38 forms a layer of the catalyst ink 34 with approximately the same thickness as the metal mask 22.

[0028] The drying device 26 is disposed above the polymer electrolyte membrane 12 and behind the blade 38 (applicator 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 hot wires or hot air to the catalyst ink 34. Here, "drying" means that at least a portion of the ink solvent contained in the catalyst ink 34 is volatilized, causing the catalyst ink 34 to become a solid state with substantially no fluidity, but does not necessarily mean that all of the ink solvent is volatilized and removed. When the polymer electrolyte membrane 12 is thin, the polymer electrolyte membrane 12 is prone to deformation due to rippling of the swelling solvent 32. Therefore, to prevent rippling of the swelling solvent 32, it is preferable that the drying device 26 only applies hot wires to the catalyst ink 34 without blowing air.

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

[0030] As shown in FIG. 4, first, a catalyst ink 34 preparation step (step S10) is performed. The catalyst ink 34 is prepared by kneading carrier particles, ionomer powder, and an ink solvent. The ink solvent is, for example, a solvent containing alcohol as a main component and a small amount of water. The prepared catalyst ink 34 is 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 storage unit 18. The swelling solvent 32 is, for example, water. The swelling solvent 32 is circulated by a pump 28 and heated to a predetermined temperature by a 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 below, and to make the interface state between the polymer electrolyte membrane 12 and the catalyst ink 34 uniform. Because the interface state 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 making the catalyst layer 14 uniform.

[0032] Next, an attachment step (step S30) is performed in which the polymer electrolyte membrane 12 is attached to the frame-shaped jig 20. When a metal mask 22 is used, the attachment step also includes a metal mask placement 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 above the solvent storage section 18. In 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 infiltrates 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 with no droplets of the swelling solvent 32 present.

[0034] Next, an application 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 application step is performed by ejecting the catalyst ink 34 from an ink supply unit 36 ​​onto the upper surface 22b of the metal mask 22 and then moving a blade 38 in the direction of arrow A in FIG. 2. The movement of the blade 38 applies the catalyst ink 34 to the polymer electrolyte membrane 12 exposed in the openings 22a of the metal mask 22. The application 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, the difference in expansion coefficient between the catalyst layer 14 and the polymer electrolyte membrane 12 is smaller than when the catalyst ink 34 is applied with swelling of the polymer electrolyte membrane 12 suppressed, and therefore, the occurrence of wrinkles in the polymer electrolyte membrane 12 and the occurrence of thin portions in the catalyst layer 14 can be suppressed.

[0035] Thereafter, a drying step (step S60) is performed to dry the catalyst ink 34. The drying step is performed by applying hot rays (or hot air, if necessary) from the drying device 26 of FIG. 2 to the catalyst ink 34 to heat the catalyst ink 34. Drying by the drying device 26 is performed while the drying device 26 is moving so as to follow the blade 38 of the coating device 24. This eliminates the need to provide a separate dryer and an associated conveying device, making it possible to simplify the manufacturing apparatus 16 and save space. Furthermore, deformation of the polymer electrolyte membrane 12 due to factors such as vibration during transportation and handling is suppressed, thereby improving the quality of the membrane electrode assembly 10.

[0036] Furthermore, the drying step is carried out with the second surface 12b of the polymer electrolyte membrane 12 in contact with the swelling solvent 32. Therefore, even if part of the swelling solvent 32 contained in the polymer electrolyte membrane 12 volatilizes during the drying step, the swelling solvent 32 is quickly supplied from the second surface 12b side. This allows the catalyst ink 34 to dry while keeping the polymer electrolyte membrane 12 swollen, and shrinkage of the polymer electrolyte membrane 12 during the drying step is suppressed.

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

[0038] 4 (steps S10, S20, S30, S40, S50, and S60) may also be used to form the catalyst layer 14 on the second surface 12b of the polymer electrolyte membrane 12. In this case, the catalyst ink 34 is applied to the second surface 12b of the polymer electrolyte membrane 12 and dried while the first surface 12a on which the catalyst layer 14 has been formed is 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 performed by transferring (affixing) 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] The above steps complete the membrane electrode assembly 10 having the polymer electrolyte membrane 12 and the catalyst layer 14. The membrane electrode assembly 10 thus completed may be supplied to an electrochemical cell assembly process with the polymer electrolyte membrane 12 still swollen.

[0041] (Second embodiment) 5, the membrane electrode assembly manufacturing apparatus 16A of this embodiment continuously applies and dries a catalyst ink 34 to a polymer electrolyte membrane 12A wound in a roll shape. In the configuration of the membrane electrode assembly manufacturing apparatus 16A of this embodiment, the same components as those of the membrane electrode assembly manufacturing apparatus 16 described with reference to FIGS. 2 and 3 are designated by the same reference numerals, and detailed description thereof will be omitted.

[0042] 5, the membrane electrode assembly manufacturing apparatus 16A includes a roll supply unit 40, a roll winding unit 42, and a second frame-shaped jig 20A in addition to the solvent storage unit 18, the coater 24, the dryer 26, the pump 28, and the solvent warmer 30. The configurations of the solvent storage unit 18, the coater 24, the dryer 26, the pump 28, and the solvent warmer 30 are similar to the corresponding configurations of the membrane electrode assembly manufacturing apparatus 16 described with reference to FIGS.

[0043] The roll supply unit 40 supplies the polymer electrolyte membrane 12A wound in a roll to the solvent storage unit 18. The roll take-up unit 42 takes up the polymer electrolyte membrane 12A on which the catalyst layer 14 has been formed in a roll. The polymer electrolyte membrane 12A supplied from the roll supply unit 40 moves in the direction of arrow B in the solvent storage unit 18 and is taken up by the roll take-up unit 42.

[0044] The second frame-shaped jig 20A includes a first roller unit 44 and a second roller unit 46. The first roller unit 44 is attached to one end of the solvent storage unit 18, and the second roller unit 46 is attached to the other end of the solvent storage unit 18. The polymer electrolyte membrane 12A supplied from the roll supply unit 40 enters the solvent storage unit 18 via the first roller unit 44 and is discharged from the solvent storage unit 18 via the second roller unit 46. The first roller unit 44 and the second roller unit 46 bring the second surface 12b of the polymer electrolyte membrane 12A into contact with the swelling solvent 32 while maintaining the polymer electrolyte membrane 12A in a taut state without wrinkles.

[0045] The applicator 24 applies catalyst ink 34 to the first surface 12a of the polymer electrolyte membrane 12A while the polymer electrolyte membrane 12A is continuously moving. The dryer 26 is disposed behind the applicator 24 in the direction of relative movement with respect to the polymer electrolyte membrane 12A, and dries the applied catalyst ink 34.

[0046] A catalyst layer 14 (electrode layer) is formed on the first surface 12a of the polymer electrolyte membrane 12A by drying the catalyst ink 34. The polymer electrolyte membrane 12A with the catalyst layer 14 formed thereon passes through the second roller unit 46 and is taken up by the roll take-up unit 42.

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

[0048] The application and drying of the catalyst ink 34 to the second surface 12b can also be performed in the same manner as above, while bringing the first surface 12a, on which the catalyst layer 14 has been formed, into contact with the swelling solvent 32. The formation of the catalyst layer 14 on the second surface 12b may also be performed by transferring (affixing) a separately formed catalyst.

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

[0050] The following additional notes are further disclosed regarding the above embodiment.

[0051] (Appendix 1) The method for manufacturing a membrane electrode assembly (10) of the present disclosure includes a coating step (step S50) of coating a catalyst ink (34) on 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 in a state where a second surface (12b) of the polymer electrolyte membrane opposite to the first surface is in contact with a swelling solvent (32) that swells the polymer electrolyte membrane.

[0052] According to the above method, the catalyst ink can be applied while the polymer electrolyte membrane is maintained in a swollen state, thereby suppressing the occurrence of wrinkles in the membrane electrode assembly and thin portions in the catalyst layer when assembling an electrochemical cell.

[0053] (Appendix 2) In the method for producing a membrane electrode assembly according to Appendix 1, 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 dry quickly.

[0054] (Appendix 3) In the method for producing a membrane electrode assembly according to Appendix 1, the swelling solvent may be heated water. This method can promote drying of the catalyst ink.

[0055] (Appendix 4) In the method for producing a membrane electrode assembly according to Appendix 1, the swelling solvent may be kept in a fluidized state. This method makes it possible to keep the temperature of the polymer electrolyte membrane uniform, and to keep the interface between the electrode ink and the polymer electrolyte membrane uniform, thereby forming a homogeneous catalyst layer.

[0056] (Appendix 5) The method for producing a membrane electrode assembly according to Appendix 1 may further include a metal mask placement step of placing a metal mask (22) on the first surface of the polymer electrolyte membrane prior to the coating step, wherein the catalyst ink is applied to the polymer electrolyte membrane through openings (22a) in the metal mask. According to this method, the mask can prevent rippling of the liquid surface of the swelling solvent, thereby suppressing deformation of the polymer electrolyte membrane.

[0057] (Appendix 6) In the method for producing a membrane electrode assembly according to Appendix 1, the drying step may include heating the catalyst ink while the second surface of the polymer electrolyte membrane is in contact with the swelling solvent to dry the catalyst ink. This method can prevent shrinkage of the polymer electrolyte membrane during the drying step.

[0058] (Appendix 7) In the method for producing a membrane electrode assembly according to any one of Supplementary Notes 1 to 6, the coating step may be performed using a production apparatus (16, 16A) including: a solvent storage section (18) for storing the swelling solvent; a frame-shaped jig (20) disposed above the solvent storage section for supporting a peripheral portion of the polymer electrolyte membrane while bringing the second surface of the polymer electrolyte membrane into contact with the swelling solvent; and an applicator (24) disposed above the polymer electrolyte membrane for applying the catalyst ink to the polymer electrolyte membrane. Prior to the coating step, a solvent supplying step (step S20) for supplying the swelling solvent to the solvent storage section and a swelling step (step S40) for supporting the polymer electrolyte membrane on the frame-shaped jig and bringing the second surface of the polymer electrolyte membrane into contact with the swelling solvent may be performed. This method allows the frame-shaped jig to stabilize the shape of the polymer electrolyte membrane, thereby forming a membrane electrode assembly with minimal irregularities.

[0059] (Appendix 8) In the method for manufacturing a membrane electrode assembly according to Supplementary Note 7, the manufacturing apparatus may further include a drying device (26) that heats and dries the catalyst ink applied to the first surface of the polymer electrolyte membrane, the drying device being disposed behind the application device in a relative movement direction of the application device with respect to the polymer electrolyte membrane, and the drying step may be performed by moving the drying device relative to the polymer electrolyte membrane so as to follow the application device. According to this method, the drying is performed immediately after the application step, which simplifies the equipment and reduces variations in the quality of the membrane electrode assembly.

[0060] (Appendix 9) A membrane electrode assembly manufacturing apparatus (16, 16A) of the present disclosure includes a solvent storage section (18) that stores a swelling solvent (32), a frame-shaped jig (20) that is provided above the solvent storage section and that supports a peripheral portion of a polymer electrolyte membrane (12, 12A) while bringing the polymer electrolyte membrane into contact with the swelling solvent, an applicator (24) that is disposed above the polymer electrolyte membrane and that applies a catalyst ink (34) to the polymer electrolyte membrane, and a dryer (26) that heats and dries the catalyst ink that has been applied to the polymer electrolyte membrane, and the dryer is disposed behind the applicator in the direction of relative movement of the applicator with respect to the polymer electrolyte membrane.

[0061] According to the above-mentioned configuration, the catalyst ink can be applied to the polymer electrolyte membrane in a swollen state, thereby suppressing the occurrence of wrinkles in the membrane electrode assembly and the occurrence of thin portions in the catalyst layer.

[0062] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments. [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 storage section 20...Frame-shaped jig 22...Metal mask 22a...Opening 24...Applicator 26...Drying device 32...Swelling solvent 34...catalytic ink

Claims

1. a coating step of coating a catalyst ink on a first surface of a polymer electrolyte membrane; a drying step of drying the applied catalyst ink; and the coating step is carried out in a state where a second surface of the polymer electrolyte membrane opposite to the first surface is in contact with a swelling solvent that swells the polymer electrolyte membrane.

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

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

4. 2. The method for producing a membrane electrode assembly according to claim 1, wherein the swelling solvent is maintained in a fluid state.

5. 2. A method for producing the membrane electrode assembly according to claim 1, comprising: a metal mask placement step of placing a metal mask on the first surface of the polymer electrolyte membrane prior to the coating step; In the coating step, the catalyst ink is applied to the polymer electrolyte membrane through openings in the metal mask.

6. 2. A method for producing the membrane electrode assembly according to claim 1, comprising: 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 producing a membrane electrode assembly according to any one of claims 1 to 6, comprising: The coating step includes: a solvent storage section that stores the swelling solvent; a frame-shaped jig provided on the solvent storage section, the frame-shaped jig supporting a peripheral portion of the polymer electrolyte membrane and bringing the second surface of the polymer electrolyte membrane into contact with the swelling solvent; an application device disposed above the polymer electrolyte membrane and configured to apply the catalyst ink to the polymer electrolyte membrane; Prior to the coating step, a solvent supplying step of supplying the swelling solvent to the solvent storage section; a swelling step of supporting the polymer electrolyte membrane on the frame-shaped jig and contacting the second surface of the polymer electrolyte membrane with the swelling solvent.

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

9. a solvent storage section that stores a swelling solvent; a frame-shaped jig provided on the solvent storage section, supporting a peripheral portion of the polymer electrolyte membrane and bringing the polymer electrolyte membrane into contact with the swelling solvent; an applicator disposed above the polymer electrolyte membrane and configured to apply a catalyst ink to the polymer electrolyte membrane; a drying device that heats and dries the catalyst ink applied to the polymer electrolyte membrane, The apparatus for manufacturing a membrane electrode assembly, wherein the drying device is disposed behind the coating device in a direction of relative movement of the coating device with respect to the polymer electrolyte membrane.

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