Membrane electrode assembly manufacturing method and membrane electrode assembly manufacturing device

Abstract

The invention provides a method for manufacturing a membrane electrode assembly and an apparatus for manufacturing the membrane electrode assembly. This method for producing a membrane electrode assembly (10) comprises: a coating step (step S50) in which a catalyst ink (34) is coated on a first surface (12a) of a polymer electrolyte membrane (12); and a drying step in which the applied catalyst ink (34) is dried, and the application step (step S50) is performed in a state in which a second surface (12b) of the polymer electrolyte membrane (12) on the opposite side from the first surface (12a) is brought into contact with a swelling solvent (32) for swelling the polymer electrolyte membrane (12). Therefore, the performance of the membrane electrode assembly can be further improved.

Description

Technical Field

[0001] This invention relates to a method and apparatus for manufacturing a membrane electrode assembly (MEA). Background Technology

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

[0003] For example, Japanese Patent Publication No. 2014-067539 describes a method for manufacturing a membrane electrode assembly by coating the surface of a polymer electrolyte membrane with catalyst ink. Summary of the Invention

[0004] There is a need to further improve the performance of membrane electrode assemblies used in electrochemical cells.

[0005] The purpose of this invention is to solve the above-mentioned technical problems.

[0006] The first aspect of the present invention is a method for manufacturing a membrane electrode assembly, comprising a coating step and a drying step, wherein, in the coating step, a catalyst ink is coated on a first surface of a polymeric electrolyte membrane; and in the drying step, the coated catalyst ink is dried, wherein the coating step is performed while a second surface of the polymeric electrolyte membrane opposite to the first surface is in contact with a swelling solvent, the swelling solvent being used to swell the polymeric electrolyte membrane.

[0007] A second aspect of the present invention is a manufacturing apparatus for a membrane electrode assembly, comprising a solvent receiving section, a frame-shaped clamp, a coating apparatus, and a drying apparatus. The solvent receiving section receives a swollen solvent. The frame-shaped clamp is disposed above the solvent receiving section, supporting the periphery of a polymer electrolyte membrane while bringing the polymer electrolyte membrane into contact with the swollen solvent. The coating apparatus is disposed above the polymer electrolyte membrane and coats the polymer electrolyte membrane with catalyst ink. The drying apparatus heats the catalyst ink coated on the polymer electrolyte membrane to dry it. The drying apparatus is disposed behind the coating apparatus in the direction of movement of the coating apparatus relative to the polymer electrolyte membrane.

[0008] According to the present invention, since the deformation caused by the swelling of the polymer electrolyte membrane is suppressed, the performance of the membrane electrode assembly can be further improved.

[0009] The above-described objectives, features, and advantages should be readily understood through the description of the following embodiments with reference to the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view of the membrane electrode assembly.

[0011] Figure 2 This is an explanatory diagram of the manufacturing apparatus for the membrane electrode assembly according to the first embodiment.

[0012] Figure 3 It is indicated from above. Figure 2 An explanatory diagram of the apparatus for manufacturing membrane electrode assemblies.

[0013] Figure 4 This is a flowchart illustrating a method for manufacturing a membrane electrode assembly according to the first embodiment.

[0014] Figure 5 This is an explanatory diagram of the manufacturing apparatus for the membrane electrode assembly according to the second embodiment.

[0015] Figure 6 This is a photograph showing the wrinkles that occur when the membrane electrode assembly involved in the comparative example swells. Detailed Implementation

[0016] (First Embodiment) like Figure 1 As shown, the membrane electrode assembly 10 manufactured using the method described in this embodiment has a polymeric electrolyte membrane 12 and a catalyst layer 14 stacked on the polymeric electrolyte membrane 12. The catalyst layer 14 is formed on the surfaces of the polymeric electrolyte membrane 12, namely the first surface 12a and the second surface 12b. The polymeric electrolyte membrane 12 is, for example, a cation exchange membrane with hydrogen ion conductivity or an anion exchange membrane with hydroxide ion conductivity. The membrane thickness of the polymeric electrolyte membrane 12 is suitably selected in the range of 5 μm to 300 μm depending on the application.

[0017] The catalyst layer 14 is also referred to as the electrode layer. The catalyst layer 14 is composed of a mixture containing support particles such as carbon and ionomers. The support particles carry catalyst particles made of, for example, platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), or alloys thereof. The ionomers are composed of ion-conducting polymers that serve as pathways for ion transport. The catalyst layer 14 is a porous body, with open pores formed between the support particles and the ion-conducting polymers. Furthermore, in this embodiment, an annular catalyst layer 14 (used in water electrolysis devices or electrochemical hydrogen pumps, etc.) Figure 2 The example is taken as an illustration, but the shape of the catalyst layer 14 is not limited to this. The shape of the catalyst layer 14 can also be a rectangular shape commonly used in fuel cells.

[0018] The membrane electrode assembly 10 is sandwiched in the thickness direction by a pair of gas diffusion layers (not shown) and sandwiched in the thickness direction by a pair of separators across the gas diffusion layers, thereby forming an electrochemical cell.

[0019] For example, some electrochemical cells, such as electrochemical hydrogen pumps and water electrolysis devices, are used in a higher water content state than fuel cells. Therefore, electrochemical cells tend to deform during use due to the swelling of the polymer electrolyte membrane 12. To prevent this adverse condition, the inventors of this application are investigating a process in which the membrane electrode assembly 10 is pre-swelled by immersing it in water before assembling the electrochemical cell.

[0020] However, as Figure 6 As shown, when the membrane electrode assembly 10A (comparative example) manufactured by the prior art is immersed in water, wrinkles are generated due to the difference in swelling ratio between the polymer electrolyte membrane and the catalyst layer.

[0021] Therefore, in this embodiment, the membrane electrode assembly 10 is manufactured using the membrane electrode assembly manufacturing apparatus 16 described below.

[0022] like Figure 2 and Figure 3 As shown, the membrane electrode assembly manufacturing apparatus 16 of this embodiment includes a solvent receiving section 18, a frame-shaped fixture 20, a metal mask 22, a coating apparatus 24, a drying apparatus 26, a pump 28, and a solvent heating apparatus 30. The solvent receiving section 18 is a container with a predetermined depth, and its periphery is surrounded by side walls 18a. Viewed from above, the solvent receiving section 18 is rectangular in shape. The solvent receiving section 18 receives swollen solvent 32 within the container surrounded by the side walls 18a. The solvent receiving section 18 has an upper opening, and at the upper part of the solvent receiving section 18, the liquid surface 32a of the swollen solvent 32 is exposed.

[0023] The swelling solvent 32 is a solvent used to wet the polymer electrolyte membrane 12 and cause it to swell. For example, water, alcohols, or mixtures thereof can be used as the swelling solvent 32. Preferably, the swelling solvent 32 has a boiling point that is the same as or higher than the boiling point (initial boiling point) of the solvent used in the catalyst ink 34 described later.

[0024] Pump 28 causes the swollen solvent 32 to flow inside the solvent receiving section 18. Pump 28 suppresses the formation of localized high temperatures in the swollen solvent 32 due to heating by the drying device 26 by circulating the swollen solvent 32. In the illustrated example, pump 28 is disposed outside the solvent receiving section 18, but it is not limited to this; pump 28 may also be disposed inside the solvent receiving section 18.

[0025] The solvent heating device 30 heats the swollen solvent 32 inside the solvent receiving section 18 to a predetermined temperature higher than room temperature. The solvent heating device 30 heats the swollen solvent 32, for example, to a temperature higher than the boiling point (initial boiling point) of the catalyst ink 34 and lower than the boiling point of the swollen solvent 32.

[0026] A frame-shaped clamp 20 is positioned above the solvent receiving section 18. The frame-shaped clamp 20 is rectangular when viewed from above. The frame-shaped clamp 20 is segmented vertically to clamp and hold the periphery of the polymer electrolyte membrane 12 and the periphery of the metal mask 22 from both vertical directions. The frame-shaped clamp 20 supports the polymer electrolyte membrane 12 with its first surface 12a facing upwards and its second surface 12b facing downwards in a wrinkle-free manner. The second surface 12b of the polymer electrolyte membrane 12 is exposed inside the frame-shaped clamp 20. When the frame-shaped clamp 20 is installed in the solvent receiving section 18, the second surface 12b of the polymer electrolyte membrane 12 is in contact with the liquid surface 32a of the swollen solvent 32.

[0027] Furthermore, the shape of the frame clamp 20 when viewed from above is not limited to a rectangular shape. The frame clamp 20 may also be configured to hold only the two opposing sides of the polymer electrolyte membrane 12. Additionally, the shape of the frame clamp 20 when viewed from above may also be annular.

[0028] The metal mask 22 is disposed such that it covers 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 catalyst layer 14. The metal mask 22 and the polymer electrolyte membrane 12 are supported together by a frame-like clamp 20. 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 at the opening 22a of the metal mask 22. The catalyst layer 14 of a predetermined shape can be formed through the opening 22a of the metal mask 22. In addition, the metal mask 22 is formed of a material with higher rigidity than the polymer electrolyte membrane 12, thereby preventing fluctuations in the liquid surface 32a of the swelling solvent 32 and preventing deformation of the polymer electrolyte membrane 12.

[0029] Furthermore, when the thickness of the polymer electrolyte membrane 12 is, for example, around 100 μm, the polymer electrolyte membrane 12 itself prevents fluctuations in the swelling solvent 32. Therefore, deformation caused by fluctuations in the swelling solvent 32 can be suppressed without installing the metal mask 22. Thus, depending on the thickness of the polymer electrolyte membrane 12, the metal mask 22 can be omitted. In this case, a flexible mask made of resin sheets or the like can also be used. Alternatively, after the polymer electrolyte membrane 12 is adhered to the metal mask 22, it can be mounted on the frame-shaped clamp 20.

[0030] The coating apparatus 24 includes an ink supply unit 36 ​​and a doctor 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.

[0031] Catalyst ink 34 is a paste-like liquid formulation containing carrier particles, ionomers, and ink solvent. The ink solvent may be, for example, an alcohol such as ethanol, methanol, and propanol, or a mixture of these alcohols and water. For rapid drying, the ink solvent is selected from solvents having the same or higher volatility as the swelling solvent 32. 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.

[0032] The doctor blade 38 is a plate-shaped component that slides against the upper surface 22b of the metal mask 22. The doctor blade 38 applies the catalyst ink 34 by sliding along the upper surface 22b of the metal mask 22 in a predetermined direction. The catalyst ink 34 applied by the doctor blade 38 enters the opening 22a of the metal mask 22 and is coated on the first surface 12a of the polymer electrolyte membrane 12 exposed at the opening 22a. The doctor blade 38 forms a layer of catalyst ink 34 with a thickness approximately the same as that of the metal mask 22.

[0033] The drying device 26 is positioned above the polymer electrolyte membrane 12 and behind the doctor blade 38 (coating device 24) in the direction of movement of the polymer electrolyte membrane 12. The drying device 26 dries the catalyst ink 34 by applying heat radiation or hot air to the coated catalyst ink 34. Here, "drying" means that at least a portion of the ink solvent contained in the catalyst ink 34 evaporates, making the catalyst ink 34 a substantially non-flowing solid state; it does not necessarily mean that all the ink solvent evaporates and is removed. When the polymer electrolyte membrane 12 is thin, the polymer electrolyte membrane 12 is prone to deformation due to fluctuations in the swelling solvent 32. Therefore, to prevent fluctuations in the swelling solvent 32, it is preferable that the drying device 26 applies heat radiation to the catalyst ink 34 without blowing air.

[0034] The manufacturing apparatus 16 for the membrane electrode assembly according to this embodiment is configured as described above. The manufacturing method of the membrane electrode assembly 10 will now be described.

[0035] like Figure 4As shown, firstly, the catalyst ink 34 is prepared (step S10). The catalyst ink 34 is prepared by mixing carrier particles, ionomer powder, and ink solvent. The ink solvent is, for example, a solvent with ethanol as the main component and containing a small amount of water. The prepared catalyst ink 34 is then filled into the ink supply section 36.

[0036] Next, a solvent supply process (step S20) is performed to supply the specified swelling solvent 32 to the solvent receiving unit 18. The swelling solvent 32 is, for example, water. The swelling solvent 32 is circulated by the pump 28 and heated to a specified temperature by the solvent heating device 30. By keeping the swelling solvent 32 flowing, the temperature rise of the polymer electrolyte membrane 12 in the drying process described later can be prevented, and the interface state between the polymer electrolyte membrane 12 and the catalyst ink 34 can be made uniform. Since the interface state between the polymer electrolyte membrane 12 and the catalyst ink 34 affects the porous structure of the dried catalyst layer 14, keeping the swelling solvent 32 in a flowing state helps to homogenize the catalyst layer 14.

[0037] Next, the installation process of mounting the polymer electrolyte membrane 12 on the frame fixture 20 is performed (step S30). Alternatively, if a metal mask 22 is used, a metal mask placement process is performed in the installation process to place the metal mask 22 on the first surface 12a of the polymer electrolyte membrane 12. The metal mask 22 is mounted together with the polymer electrolyte membrane 12 on the frame fixture 20.

[0038] Next, a swelling process (step S40) is performed, in which the second surface 12b of the polymer electrolyte membrane 12 comes into contact with the liquid surface 32a of the swelling solvent 32. The swelling process is performed by placing the frame-shaped clamp 20 on the upper part of the solvent receiving section 18. Through the swelling process, the second surface 12b of the polymer electrolyte membrane 12 comes into contact with the swelling solvent 32, and the swelling solvent 32 wets the polymer electrolyte membrane 12, thereby causing the polymer electrolyte membrane 12 to swell. At this time, the first surface 12a remains dry, free of droplets of the swelling solvent 32.

[0039] Next, a coating process (step S50) is performed to coat the catalyst ink 34 onto the first surface 12a of the polymer electrolyte membrane 12. The coating process involves discharging the catalyst ink 34 from the ink supply section 36 onto the upper surface 22b of the metal mask 22, after which the doctor blade 38 moves along... Figure 2The process is performed by moving in the direction of arrow A. The catalyst ink 34 is applied to the polymer electrolyte membrane 12 exposed at the opening 22a of the metal mask 22 by moving the scraper 38. The coating process is performed while the second surface 12b of the polymer electrolyte membrane 12 is in contact with the swelling solvent 32. According to this embodiment, compared to the case where the catalyst ink 34 is applied while the swelling of the polymer electrolyte membrane 12 is suppressed, the difference in swelling ratio between the catalyst layer 14 and the polymer electrolyte membrane 12 is smaller. Therefore, it is possible to suppress wrinkles in the polymer electrolyte membrane 12 and thinner portions of the catalyst layer 14.

[0040] Following this, a drying process (step S60) is performed to dry the catalyst ink 34. The drying process is carried out by... Figure 2 The drying apparatus 26 applies heat radiation (hot air if necessary) to the catalyst ink 34 to heat it. Drying is performed by moving the drying apparatus 26 along with the doctor blade 38 of the coating apparatus 24. Therefore, a separate dryer and its associated conveying device are not required, simplifying the manufacturing apparatus 16 and saving space. Furthermore, deformation of the polymer electrolyte membrane 12 caused by vibration and handling during transport is suppressed, thus improving the quality of the membrane electrode assembly 10.

[0041] Furthermore, the drying process is performed while the second surface 12b of the polymer electrolyte membrane 12 is 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 can be rapidly supplied from the second surface 12b side. Thus, the catalyst ink 34 can be dried while the polymer electrolyte membrane 12 is swollen, thereby suppressing the shrinkage of the polymer electrolyte membrane 12 during the drying process.

[0042] Thus, a catalyst layer 14 is formed on the first surface 12a of the polymer electrolyte membrane 12. Subsequently, another metal mask 22 may be disposed above the first surface 12a of the polymer electrolyte membrane 12 as needed for the coating and drying of the second or subsequent catalyst ink 34.

[0043] Additionally, the second surface 12b of the polymer electrolyte membrane 12 can also be based on a reference. Figure 4 The catalyst layer 14 is formed using the described steps (steps S10, S20, S30, S40, S50, S60). In this case, catalyst ink 34 is coated onto the second surface 12b of the polymer electrolyte membrane 12, and the catalyst ink 34 is dried while the first surface 12a, where the catalyst layer 14 is formed, is in contact with the swollen solvent 32.

[0044] Alternatively, the process of forming a catalyst layer 14 on the second surface 12b of the polymer electrolyte membrane 12 can also be performed by transferring (adhering) a catalyst layer 14 pre-formed into a predetermined shape onto the second surface 12b of the polymer electrolyte membrane 12.

[0045] Through the above processes, the membrane electrode assembly 10 having the polymer electrolyte membrane 12 and the catalyst layer 14 is completed. The membrane electrode assembly 10 thus completed can be supplied to the assembly process of the electrochemical cell in a swollen state of the polymer electrolyte membrane 12.

[0046] (Second Implementation) like Figure 5 As shown, the membrane electrode assembly manufacturing apparatus 16A of this embodiment continuously coats and dries the catalyst ink 34 onto the polymer electrolyte membrane 12A wound into a roll. Furthermore, in the structure of the membrane electrode assembly manufacturing apparatus 16A of this embodiment, the edge reference... Figure 2 and Figure 3 The same structure as the membrane electrode assembly manufacturing apparatus 16 described above is used, and the same reference numerals are used in the accompanying drawings. Detailed descriptions of the apparatus are omitted.

[0047] like Figure 5 As shown, in addition to the solvent receiving unit 18, coating apparatus 24, drying apparatus 26, pump 28, and solvent heating apparatus 30, the membrane electrode assembly manufacturing apparatus 16A also includes a roll material supply unit 40, a roll material winding unit 42, and a second frame-shaped fixture 20A. The structure and side references of the solvent receiving unit 18, coating apparatus 24, drying apparatus 26, pump 28, and solvent heating apparatus 30 are shown. Figure 2 and Figure 3 The structure of the manufacturing apparatus 16 for the membrane electrode assembly described above is the same.

[0048] The roll material supply unit 40 supplies a rolled polymer electrolyte membrane 12A to the solvent collection unit 18. The roll material take-up unit 42 takes the polymer electrolyte membrane 12A, on which the catalyst layer 14 is formed, into a roll. The polymer electrolyte membrane 12A supplied by the roll material supply unit 40 moves in the direction of arrow B in the solvent collection unit 18 and is taken up by the roll material take-up unit 42.

[0049] The second frame-shaped clamp 20A has a first roller portion 44 and a second roller portion 46. The first roller portion 44 is mounted at one end of the solvent receiving portion 18, and the second roller portion 46 is mounted at the other end of the solvent receiving portion 18. The polymer electrolyte membrane 12A supplied by the roll material supply portion 40 enters the solvent receiving portion 18 through the first roller portion 44 and exits from the solvent receiving portion 18 through the second roller portion 46. The first roller portion 44 and the second roller portion 46 keep the polymer electrolyte membrane 12A in a wrinkle-free and taut state while contacting the second surface 12b of the polymer electrolyte membrane 12A with the swollen solvent 32.

[0050] The coating apparatus 24 coats the first surface 12a of the polymer electrolyte membrane 12A with catalyst ink 34 while the polymer electrolyte membrane 12A is continuously moving. The drying apparatus 26 is disposed behind the coating apparatus 24 relative to the direction of relative movement of the polymer electrolyte membrane 12A, and is used to dry the coated catalyst ink 34.

[0051] By drying the catalyst ink 34, 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 thereon is wound up by the roll winding section 42 via the second roller section 46.

[0052] In this embodiment, the coating and drying of the catalyst ink 34 are also performed while the second surface 12b of the polymer electrolyte membrane 12A is in contact with the swelling solvent 32.

[0053] Furthermore, the coating of the catalyst ink 34 onto the second surface 12b and the drying of the catalyst ink can also be carried out using the same method as described above, while the first surface 12a, where the catalyst layer 14 is formed, is in contact with the swelling solvent 32. Alternatively, the formation of the catalyst layer 14 on the second surface 12b can also be performed by transferring (adhering) a separately formed catalyst.

[0054] The same effect as the first embodiment can be obtained in this embodiment.

[0055] The following notes are also disclosed regarding the above-described embodiments.

[0056] (Postscript 1) The manufacturing method of the membrane electrode assembly (10) of the present invention includes a coating step (step S50) and a drying step (step S60), wherein, in the coating step, a catalyst ink (34) is coated on the first surface (12a) of the polymer electrolyte membrane (12, 12A); in the drying step, the coated catalyst ink is dried, and the coating step is performed while the second surface (12b) of the polymer electrolyte membrane opposite to the first surface is in contact with a swelling solvent (32), the swelling solvent (32) being used to swell the polymer electrolyte membrane.

[0057] According to the above method, since the catalyst ink can be applied while maintaining the state of swelling of the polymer electrolyte membrane, it is possible to suppress the formation of wrinkles in the membrane electrode assembly and the formation of thinner portions of the catalyst layer during the assembly of the electrochemical cell.

[0058] (Postscript 2) According to the manufacturing method of the membrane electrode assembly described in 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 enables the catalyst ink to dry rapidly.

[0059] (Note 3) According to the manufacturing method of the membrane electrode assembly described in Appendix 1, the swelling solvent may also be heated water. This method can promote the drying of the catalyst ink.

[0060] (Postscript 4) According to the method for manufacturing the membrane electrode assembly described in Appendix 1, the swelling solvent may also be kept in a flowing state. This method enables the uniform temperature of the polymer electrolyte membrane and the uniform interfacial state between the electrode ink and the polymer electrolyte membrane, thereby forming a homogeneous catalyst layer.

[0061] (Note 5) According to the manufacturing method of the membrane electrode assembly described in Appendix 1, a metal mask preparation step may be included before the coating step. In this metal mask preparation step, a metal mask (22) is placed above the first surface of the polymer electrolyte membrane, and in the coating step, the catalyst ink is coated onto the polymer electrolyte membrane through the opening (22a) of the metal mask. According to this method, the surface fluctuation of the swelling solvent can be prevented by the mask, thereby suppressing the deformation of the polymer electrolyte membrane.

[0062] (Note 6) According to the manufacturing method of the membrane electrode assembly described in Appendix 1, the catalyst ink can also be dried by heating the catalyst ink while the second surface of the polymer electrolyte membrane is in contact with the swelling solvent during the drying process. This method prevents the polymer electrolyte membrane from shrinking during the drying process.

[0063] (Note 7) According to any one of the appendices 1 to 6, the method for manufacturing the membrane electrode assembly may also be performed using a manufacturing apparatus (16, 16A) having a solvent receiving section (18), a frame-shaped clamp (20), and a coating apparatus (24), wherein the solvent receiving section (18) receives the swelling solvent; the frame-shaped clamp (20) is disposed above the solvent receiving section, supporting the periphery of the polymer electrolyte membrane while causing the second surface of the polymer electrolyte membrane to... The second surface of the polymer electrolyte membrane is in contact with the swelling solvent. The coating apparatus (24) is positioned above the polymer electrolyte membrane and coats the polymer electrolyte membrane with the catalyst ink. Before the coating process, a solvent supply process (step S20) and a swelling process (step S40) are performed. In the solvent supply process, the swelling solvent is supplied to the solvent receiving section. In the swelling process, the frame-shaped clamp supports the polymer electrolyte membrane, and the second surface of the polymer electrolyte membrane is brought into contact with the swelling solvent. According to this method, the shape of the polymer electrolyte membrane can be stabilized using the frame-shaped clamp, thus enabling the formation of a membrane electrode assembly with minimal irregularities.

[0064] (Note 8) According to the method for manufacturing the membrane electrode assembly described in Appendix 7, the manufacturing apparatus may also include a drying device (26) that heats and dries the catalyst ink coated on the first surface of the polymer electrolyte membrane. The drying device is positioned behind the coating apparatus in the direction of movement of the coating apparatus relative to the polymer electrolyte membrane. The drying process is performed by moving the drying device relative to the polymer electrolyte membrane in a manner that follows the coating apparatus. According to this method, drying is performed immediately after the coating process, thus simplifying the equipment and suppressing deviations in the quality of the membrane electrode assembly.

[0065] (Note 9) The membrane electrode assembly manufacturing apparatus (16, 16A) of the present invention includes a solvent receiving section (18), a frame clamp (20), a coating apparatus (24), and a drying apparatus (26), wherein the solvent receiving section (18) receives a swelling solvent (32); the frame clamp (20) is disposed above the solvent receiving section, supporting the periphery of the polymer electrolyte membrane (12, 12A) while bringing the polymer electrolyte membrane into contact with the swelling solvent; the coating apparatus (24) is disposed above the polymer electrolyte membrane and coats the polymer electrolyte membrane with catalyst ink (34); the drying apparatus (26) heats the catalyst ink coated on the polymer electrolyte membrane to dry it, and the drying apparatus is disposed behind the coating apparatus in the direction of movement of the coating apparatus relative to the polymer electrolyte membrane.

[0066] Based on the above structure, since the catalyst ink can be coated while the polymer electrolyte membrane is swollen, it is possible to suppress wrinkles in the membrane electrode assembly and thinner portions of the catalyst layer.

[0067] The present invention has been described in detail, but it is not limited to the various embodiments described above. Various additions, substitutions, modifications, and partial deletions can be made to these embodiments without departing from the spirit of the invention or the spirit of the invention derived from the content described in the technical solution and its equivalents. Furthermore, these embodiments can also be implemented in combination. For example, in the above embodiments, the order of each action or the order of each process is shown as an example and is not limited to these. The same applies to the use of numerical values ​​or formulas in the description of the above embodiments.

Claims

1. A method of manufacturing a membrane electrode assembly, characterized by comprising: a coating step and a drying step, wherein, in the coating step, a catalyst ink is coated on a first surface of a polymer electrolyte membrane; and in the drying step, the coated catalyst ink is dried, the coating step is performed in a state in which a second surface of the polymer electrolyte membrane, which is opposite to the first surface, is in contact with a swelling solvent for swelling the polymer electrolyte membrane.

2. The method of manufacturing a membrane electrode assembly according to claim 1, characterized in that, the boiling point of the swelling solvent is higher than the boiling point of an ink solvent contained in the catalyst ink.

3. The method of manufacturing a membrane electrode assembly according to claim 1, characterized in that, the swelling solvent is heated water.

4. The method of manufacturing a membrane electrode assembly according to claim 1, characterized in that, the swelling solvent is kept in a flowing state.

5. The method of manufacturing a membrane electrode assembly according to claim 1, characterized by further comprising a metal mask arrangement step before the coating step, in which a metal mask is arranged above the first surface of the polymer electrolyte membrane, and in the coating step, the catalyst ink is coated on the polymer electrolyte membrane through an opening portion of the metal mask.

6. The method of manufacturing a membrane electrode assembly according to claim 1, characterized in that, in the drying step, the catalyst ink is dried by heating the catalyst ink in a state in which the second surface of the polymer electrolyte membrane is in contact with the swelling solvent.

7. The method of manufacturing a membrane electrode assembly according to any one of claims 1 to 6, characterized in that, the coating step is performed using a manufacturing device, the manufacturing device has a solvent storage portion, a frame-shaped jig, and a coating device, wherein, the solvent storage portion stores the swelling solvent; the frame-shaped jig is provided above the solvent storage portion, supports 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 the coating device is arranged above the polymer electrolyte membrane, and coats the catalyst ink on the polymer electrolyte membrane, and the method further comprises a solvent supply step and a swelling step before the coating step, wherein, in the solvent supply step, the solvent storage portion is supplied with the swelling solvent; and in the swelling step, the frame-shaped jig supports the polymer electrolyte membrane, and the second surface of the polymer electrolyte membrane is brought into contact with the swelling solvent.

8. The method of manufacturing a membrane electrode assembly according to claim 7, characterized in that, the manufacturing device further has a drying device that heats and dries the catalyst ink coated on the first surface of the polymer electrolyte membrane, the drying device is arranged behind the coating device with respect to a moving direction of the coating device with respect to the polymer electrolyte membrane. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The drying process is performed by moving the drying device relative to the polymer electrolyte membrane following the coating device.

9. An apparatus for manufacturing a membrane electrode assembly, characterized by comprising: a solvent containing portion, a frame-shaped jig, a coating device, and a drying device, wherein the solvent containing portion contains a swelling solvent; the frame-shaped jig is disposed above the solvent containing portion, supports a peripheral portion of a polymer electrolyte membrane while bringing the polymer electrolyte membrane into contact with the swelling solvent; the coating device is disposed above the polymer electrolyte membrane, and coats the polymer electrolyte membrane with a catalyst ink; the drying device dries the catalyst ink coated on the polymer electrolyte membrane by heating the catalyst ink; the drying device is disposed behind the coating device in a moving direction of the coating device relative to the polymer electrolyte membrane.

10. An apparatus for manufacturing a membrane electrode assembly, characterized by comprising: a solvent containing portion, a frame-shaped jig, a coating device, and a drying device, wherein the solvent containing portion contains a swelling solvent; the frame-shaped jig is disposed above the solvent containing portion, supports a peripheral portion of a polymer electrolyte membrane while bringing the polymer electrolyte membrane into contact with the swelling solvent; the coating device is disposed above the polymer electrolyte membrane, and coats the polymer electrolyte membrane with a catalyst ink; the drying device dries the catalyst ink coated on the polymer electrolyte membrane by heating the catalyst ink; the drying device is disposed behind the coating device in a moving direction of the coating device relative to the polymer electrolyte membrane.

11. An apparatus for manufacturing a membrane electrode assembly, characterized by comprising: a solvent containing portion, a frame-shaped jig, a coating device, and a drying device, wherein the solvent containing portion contains a swelling solvent; the frame-shaped jig is disposed above the solvent containing portion, supports a peripheral portion of a polymer electrolyte membrane while bringing the polymer electrolyte membrane into contact with the swelling solvent; the coating device is disposed above the polymer electrolyte membrane, and coats the polymer electrolyte membrane with a catalyst ink; the drying device dries the catalyst ink coated on the polymer electrolyte membrane by heating the catalyst ink; the drying device is disposed behind the coating device in a moving direction of the coating device relative to the polymer electrolyte membrane.

12. An apparatus for manufacturing a membrane electrode assembly, characterized by comprising: a solvent containing portion, a frame-shaped jig, a coating device, and a drying device, wherein the solvent containing portion contains a swelling solvent; the frame-shaped jig is disposed above the solvent containing portion, supports a peripheral portion of a polymer electrolyte membrane while bringing the polymer electrolyte membrane into contact with

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