JP2012164422A - Method and apparatus of manufacturing membrane electrode assembly for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing apparatus of a membrane electrode assembly for fuel cell in which the membrane electrode assembly obtained by coating an electrolytic membrane with an electrode layer can be prevented from creasing.SOLUTION: The manufacturing apparatus of a membrane electrode assembly for fuel cell where an electrode layer is formed by coating an electrolyte membrane 2 of solid polymer with an electrode paste 1 containing alcohol as a solvent comprises three first fixed rollers 3 which fix the electrolyte membrane 2 coated with the electrode paste 1 so as not to deform and dries the electrolyte membrane 2, two second fixed rollers 4 which fix the electrolyte membrane 2 fed out by these first fixed rollers 3 so as not to deform and makes the electrolyte membrane 2 absorb moisture, and six small diameter rollers 5 arranged between these fixed rollers 3, 4. Moisture is absorbed into the electrolyte membrane 2 by leaving the electrolyte membrane 2, as it is, in normal temperature environment. Humidity of the working environment is preferably adjusted to 30-60%.

Description

  The present invention relates to a method and apparatus for producing a membrane electrode assembly for a fuel cell obtained by coating an electrode layer on a solid polymer electrolyte membrane.

In recent years, fuel cells have been developed as power sources for vehicles and the like. A membrane electrode assembly used in a fuel cell is produced by applying electrode ink or paste in which a catalyst is dispersed in a solvent such as alcohol to the surface of an electrolyte membrane using a die coater or the like. However, the electrolyte membrane has a property that it easily swells and shrinks due to the absorption state of the solvent and moisture in the electrode ink, and there is a problem that wrinkles are generated in the electrolyte membrane due to coating and drying of the electrode ink.

In order to solve such a problem, Patent Document 1 discloses a technique for fixing an electrolyte membrane on an adhesive sheet and applying and drying electrode ink so that the electrolyte membrane does not deform in the surface direction. Yes. Patent Document 2 discloses a technique in which the periphery of an electrolyte membrane is attached to a plate with a heater, and electrode ink is applied.

JP 2006-339062 A JP 2007-53064 A

However, as in the techniques described in Patent Document 1 and Patent Document 2, if the electrolyte membrane is fixed so as not to be deformed in the surface direction and the electrode ink is simply applied to the electrolyte membrane and dried, it should be generated in the electrolyte membrane. Was not enough to prevent. For example, when the electrolyte membrane is immediately released after drying, wrinkles may occur after that.

This is because the alcohol contained in the electrode ink denatures the electrolyte membrane, so that the portion coated with the electrode ink tends to shrink due to drying, and the portion that is not coated with the electrode ink swells / shrinks. This is considered to be due to the difference in internal stress between the coated and non-coated portions of the electrode ink when the dried electrolyte membrane absorbs moisture.

  The present invention has been made in view of such problems of the prior art, and the object of the present invention is to generate wrinkles in a membrane electrode assembly formed by coating an electrode layer on an electrolyte membrane. It is an object of the present invention to provide a method and apparatus for manufacturing a membrane electrode assembly for a fuel cell capable of preventing the above-described problem.

In order to solve the above problems, the invention according to claim 1 is a method of manufacturing a membrane electrode assembly for a fuel cell, which is obtained by coating an electrode layer on a solid polymer electrolyte membrane, wherein alcohol is used as a solvent in the electrolyte membrane. A coating process for coating the electrode paste, a drying process for fixing the electrolyte membrane coated with the electrode paste in the coating process to a fixing member, and a drying process for fixing the electrolyte film dried in the drying process. A moisture absorption process is provided in which the electrolyte membrane absorbs moisture while being fixed to the member.

  Further, in the moisture absorption step, the electrolyte membrane can be absorbed by the electrolyte membrane without heating the electrolyte membrane.

The invention according to claim 3 is an apparatus for manufacturing a fuel cell membrane electrode assembly, in which an electrode paste containing alcohol as a solvent is applied to a solid polymer electrolyte membrane to form an electrode layer, the manufacturing apparatus comprising: A drying unit that dries the electrode paste applied to the electrolyte membrane, and a moisture absorption unit that absorbs moisture in the electrolyte membrane that has passed through the drying unit, and the electrolyte membrane coated with the electrode paste does not deform One or a plurality of first fixing means to be fixed and a drying means for drying the electrolyte membrane fixed to the first fixing means, and the moisture absorbing part is fixed so that the dried electrolyte membrane is not deformed. The second fixing means is provided.

  The drying means is a heating and drying furnace, the first fixing means is a fixing stage for fixing an electrolyte membrane on the surface of a flat mounting table, the first fixing means is used as the second fixing means, and the first fixing means is used. A moving means for moving the fixing means from the heating / drying furnace to the moisture absorption part can be provided.

  Further, the drying means is a heating and drying furnace, and the first fixing means and the second fixing means are fixing rollers that are provided with suction holes on the side surfaces and vacuum sucked from the suction holes to fix the electrolyte membrane, The fixing roller of the first fixing means may be provided in the heating / drying furnace, and the fixing roller of the second fixing means may be provided in the moisture absorption part outside the heating / drying furnace.

  Further, the first fixing means and the second fixing means are fixing rollers provided with suction holes on the side surfaces and vacuum-suctioned from the suction holes to fix the electrolyte membrane, and the drying means is the first fixing means. The electrolyte membrane is dried by heating the fixed roller, and the fixed roller of the second fixing means can be provided with the moisture absorbing portion.

  Furthermore, a roller having a smaller diameter than the fixed roller may be disposed between the fixed rollers, and the center of the small diameter roller may be positioned on a straight line passing through the center of the fixed roller.

According to the first aspect of the present invention, by fixing the electrolyte membrane to the fixing member so as not to be deformed in the in-plane direction and drying, by providing a step of absorbing moisture in the electrolyte membrane while fixing the electrolyte membrane, Moisture is absorbed with in-plane deformation suppressed. Then, the difference in internal stress due to the swelling / shrinkage of the coated part and the non-coated part of the electrode paste decreases as moisture is absorbed by the electrolyte membrane. Therefore, if the electrolyte membrane is released when the water absorption amount of the electrolyte membrane exceeds a predetermined amount, the subsequent generation of soot can be suppressed.

Also, if the electrolyte membrane is not heated and the moisture in the atmosphere is absorbed by the electrolyte membrane, the electrolyte is not forcedly supplied, and the electrolyte membrane absorbs moisture spontaneously, so that the electrolyte swells uniformly. Thus, the occurrence of local internal stress difference can be suppressed.

  According to the invention of claim 3, since the electrolyte membrane can be dried and absorbed without releasing the fixing in the middle while the electrolyte membrane is fixed, the generation of wrinkles can be suppressed.

  Further, the first fixing means and the second fixing means may be a fixing roller provided with a suction hole on the side surface and vacuum-suctioned from the suction hole to fix the electrolyte membrane, or a heating roller that the fixing roller itself heats the electrolyte membrane. If so, the electrolyte membrane can be manufactured in a continuous state, and the manufacturing efficiency can be increased.

  Further, a roller having a smaller diameter than the fixed roller is disposed between the fixed rollers, the center of these small diameter rollers is positioned on a straight line passing through the center of the fixed roller, and the space between the fixed rollers is interposed via the small diameter roller. If the electrolyte membrane continuum passes, the non-fixed portion of the electrolyte membrane continuum between the fixed rollers can be shortened, and the generation of wrinkles of the electrolyte membrane can be further suppressed.

Outline explanatory drawing of 1st Embodiment of the manufacturing apparatus of the membrane electrode assembly for fuel cells which concerns on this invention (A) When a small diameter roller is disposed between fixed rollers, (b) When a small diameter roller is not disposed It is explanatory drawing of 2nd Embodiment of the manufacturing apparatus of the membrane electrode assembly for fuel cells which concerns on this invention, (a) is explanatory drawing of a fixed stage, (b) is explanatory drawing of the whole. Outline explanatory drawing of 3rd Embodiment of the manufacturing apparatus of the membrane electrode assembly for fuel cells which concerns on this invention

  Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the first embodiment of the fuel cell membrane electrode assembly manufacturing apparatus according to the present invention is fixed so that the electrolyte membrane 2 coated with the electrode paste (electrode ink) 1 is not deformed. In addition, three first fixed rollers 3 for drying the electrolyte membrane 2 and two first fixed rollers 3 for fixing the electrolyte membrane 2 sent out by these first fixed rollers 3 so as not to be deformed and for allowing the electrolyte membrane 2 to absorb moisture. 2 fixed rollers 4 and six small-diameter rollers 5 disposed between these fixed rollers 3 and 4.

Here, 6 is an electrolyte membrane roll for unwinding, 7 is a wound electrolyte membrane roll, 8 is a die head for applying the electrode paste 1 to the electrolyte membrane 2, and 9 is a coating having the same structure as the first fixed roller 3 A roller 10, a guide roller 10, and a paste coating portion 11 in which the electrode paste 1 is applied to the electrolyte membrane 2.

The first fixed roller 3 and the second fixed roller 4 are provided with suction holes (not shown) on their side surfaces, and the electrolyte membrane 2 is sucked and fixed by vacuum suction from the suction holes. The first fixed roller 3 is a heating roller that raises the temperature of the roller itself, and dries the fixed electrolyte membrane 2. On the other hand, the second fixed roller 4 sucks and fixes the electrolyte membrane 2 but does not heat the electrolyte membrane 2 and allows the electrolyte membrane 2 to absorb moisture. The small-diameter roller 5 has a smaller diameter than the fixed rollers 3 and 4, and the center thereof is located on a straight line passing through the centers of the fixed rollers 3 and 4.

The electrolyte membrane 2 is made of a polymer having proton conductivity. For example, a perfluorosulfonic acid polymer membrane such as Nafion (product name) manufactured by DuPont can be used. The electrode paste 1 is a mixture of a catalyst such as platinum or an alloy of platinum and other metals and a polymer having proton conductivity similar to that of the electrolyte membrane 2 and dispersed in a solvent such as water or alcohol. .

As the alcohol, ethanol or propanol is preferably used. In addition to the catalyst and polymer, other materials such as carbon fiber can be added to the electrode paste 1. In addition, a catalyst in which platinum or an alloy thereof is supported on carbon particles can also be used as the catalyst.

The operation of the fuel cell membrane electrode assembly manufacturing apparatus according to the first embodiment configured as described above and the method of manufacturing the fuel cell membrane electrode assembly will be described. First, the electrode paste 1 is applied to one surface of the electrolyte membrane 2 unwound from the electrolyte membrane roll 6 and sucked and fixed to the coating roller 9 by the die head 8 provided in the die coater (application step). Although the application shape of the electrode paste 1 applied to the electrolyte membrane 2 can be determined as appropriate, it can be, for example, a rectangular shape.

Next, the solvent component in the electrode paste 1 is evaporated, and the electrolyte membrane 2 coated with the electrode paste 1 to form an electrode layer is heated by a roller heated while being sequentially sucked and fixed to the three first fixed rollers 3. Dry (drying process). By fixing the electrolyte membrane 2 to the first fixed roller 3 by suction, deformation in the in-plane direction of the electrolyte membrane 2 can be prevented. Drying is performed by heating the electrolyte membrane 2 to, for example, 80 to 120 ° C.

  Next, the electrolyte membrane 2 dried by the three first fixed rollers 3 is further sucked and fixed to the two second fixed rollers 4 in order, and the electrolyte membrane 2 absorbs moisture (moisture absorption step). The absorption of moisture into the electrolyte membrane 2 is performed by leaving it in a room temperature environment. In addition, it is preferable to adjust the humidity of the working environment to 30% to 60%.

By adjusting the working environment humidity in this way, moisture absorption conditions can be made constant, and by setting the working environment humidity to 60% or less, rapid moisture absorption can be prevented, thus preventing wrinkles. Can be further enhanced.

  Next, when the electrolyte membrane 2 absorbs moisture in such a state and the water absorption amount of the electrolyte membrane 2 exceeds a predetermined amount (for example, when the saturated water absorption amount is 30% or more), the second fixed roller 4 to release the fixing of the electrolyte membrane 2. As described above, after the electrolyte membrane 2 is dried, the generation of wrinkles can be suppressed by absorbing the moisture in the fixed state without immediately releasing the electrolyte membrane 2 from the fixed state.

  The small-diameter roller 5 is disposed between the first fixed rollers 3 having a smaller diameter than the first fixed rollers 3 as shown in FIG. Further, the center of the small diameter roller 5 is located on a straight line 12 passing through the center of the first fixed roller 3. The small-diameter roller 5 is similarly disposed between the first fixed roller 3 and the second fixed roller 4 and between the second fixed roller 4.

  As described above, if the continuous body of the electrolyte membrane 2 passes between the fixed rollers 3 via the small-diameter roller 5, the non-fixed portion of the continuous body of the electrolyte membrane 2 between the fixed rollers 3 (crossover portion) ) 13 can be shortened. Then, as shown in FIG. 2 (b), the generation of wrinkles in the electrolyte membrane 2 can be further suppressed as compared with the case where the transition portion 13 becomes longer because the small-diameter roller 5 is not used.

Further, if the continuous body of the electrolyte membrane 2 passes between the fixed rollers 3 via the small-diameter rollers 5, the electrode paste 1 may be in direct contact with the fixed rollers 3 as shown in FIG. Absent. On the other hand, when the small-diameter roller 5 is not used, the electrode paste 1 comes into direct contact with the fixed roller 3 having a large contact surface as shown in FIG. There is a possibility that the paste 1 is dried and adheres to the fixed roller 3.

  Next, the second embodiment of the fuel cell membrane electrode assembly manufacturing apparatus according to the present invention includes, as shown in FIG. 3, a fixing stage 21 for fixing the electrolyte membrane 2 so as not to deform, and a fixing stage 21. A heating / drying furnace 22 for drying the electrolyte membrane 2 coated with the electrode ink 1 in a state of being fixed to the electrode, and a fixing stage 21 in a state of fixing the electrolyte membrane 2 from the inside of the heating / drying oven 22 to the outside of the heating / drying oven 22 The moving means 24 etc. which are moved to the moisture absorption part 23 are provided.

  As shown in FIG. 3A, the fixed stage 21 is provided on a flat plate mounting table 25 on which the electrolyte membrane 2 is mounted and a plurality of surfaces 25 a of the mounting table 25. A suction hole 25b is provided. As the moving means 24, a conveyor or the like that carries and transports the fixed stage 21 to which the electrolyte membrane 2 is fixed is used.

  The operation of the second embodiment of the fuel cell membrane electrode assembly manufacturing apparatus according to the present invention configured as described above will be described. First, the electrode ink 1 is applied to the electrolyte membrane 2 fixed to the fixed stage 21 (coating process).

Next, the fixed stage 21 in a state where the electrolyte membrane 2 is fixed is put into the heating and drying furnace 22 by the conveyor 24, and the electrolyte membrane 2 coated with the electrode ink 1 is dried (drying step). The drying operation is performed by evaporating the solvent component in the electrode ink 1 and heating the electrolyte membrane 2 to, for example, 80 to 120 ° C. in order to form an electrode layer.

  Next, the fixed stage 21 in a state where the dried electrolyte membrane 2 is fixed is moved by the conveyor 24 from the inside of the heating / drying furnace 22 to the moisture absorption part 23 outside the heating / drying furnace 22. In the moisture absorption part 23, the moisture is absorbed into the electrolyte membrane 2 by leaving it in a room temperature environment (a moisture absorption process). In addition, it is preferable to adjust the humidity of the working environment to 30% to 60%.

By adjusting the working environment humidity in this way, moisture absorption conditions can be made constant, and by setting the working environment humidity to 60% or less, rapid moisture absorption can be prevented, thus preventing wrinkles. Can be further enhanced.

  Next, in such a state, the electrolyte membrane 2 absorbs moisture, and when the water absorption amount of the electrolyte membrane 2 becomes 30% or more of the saturated water absorption amount, the fixation of the electrolyte membrane 2 by the fixing stage 21 is released.

Next, in the third embodiment of the fuel cell membrane electrode assembly manufacturing apparatus according to the present invention, as shown in FIG. 4, the electrolyte membrane 2 coated with the electrode paste (electrode ink) 1 is not deformed. The three first fixing rollers 30 are fixed in the heating / drying furnace 31 so that the electrolyte membrane 2 sent from the heating / drying furnace 31 is fixed so as not to be deformed, and the electrolyte membrane 2 absorbs moisture. Two second fixed rollers 32 are arranged in the moisture absorption part 33.

Suction holes (not shown) are provided on the side surfaces of the first fixed roller 30 and the second fixed roller 32, and the electrolyte membrane 2 is sucked and fixed by vacuum suction from the suction holes. Other configurations are the same as those of the first embodiment shown in FIG.

The operation of the third embodiment of the fuel cell membrane electrode assembly manufacturing apparatus according to the present invention configured as described above will be described. First, the electrode paste 1 is applied to one surface of the electrolyte membrane 2 unwound from the electrolyte membrane roll 6 and sucked and fixed to the coating roller 9 by the die head 8 provided in the die coater (application step). Although the application shape of the electrode paste 1 applied to the electrolyte membrane 2 can be determined as appropriate, it can be, for example, a rectangular shape.

Next, the solvent component in the electrode paste 1 is evaporated, and the electrolyte membrane 2 coated with the electrode paste 1 to form an electrode layer is sequentially sucked by the three first fixed rollers 30 disposed in the heating and drying furnace 31. Heat and dry in a fixed state (drying process). By fixing the electrolyte membrane 2 to the first fixed roller 30 by suction, deformation in the in-plane direction of the electrolyte membrane 2 can be prevented. Drying is performed by heating the electrolyte membrane 2 to, for example, 80 to 120 ° C.

  Subsequently, the electrolyte membrane 2 dried in the heating and drying furnace 31 is further sucked and fixed to the two second fixed rollers 32 arranged in the moisture absorption section 33 in order to absorb moisture in the electrolyte membrane 2 (moisture absorption step). The absorption of moisture into the electrolyte membrane 2 is performed by leaving it in a room temperature environment. In addition, it is preferable to adjust the humidity of the working environment to 30% to 60%.

By adjusting the working environment humidity in this way, moisture absorption conditions can be made constant, and by setting the working environment humidity to 60% or less, rapid moisture absorption can be prevented, thus preventing wrinkles. Can be further enhanced.

Next, when the electrolyte membrane 2 absorbs moisture in such a state and the water absorption amount of the electrolyte membrane 2 exceeds a predetermined amount (for example, when the saturated water absorption amount is 30% or more), the second fixed roller The fixing of the electrolyte membrane 2 by 32 is released. As described above, after the electrolyte membrane 2 is dried, the generation of wrinkles can be suppressed by absorbing the moisture in the fixed state without immediately releasing the electrolyte membrane 2 from the fixed state.

According to the present invention, since the electrolyte membrane can be dried and moisture-absorbed without releasing the fixing in the middle while the electrolyte membrane is fixed, the membrane electrode assembly for a fuel cell in which the generation of soot is suppressed The manufacturing method and apparatus thereof can be provided.

DESCRIPTION OF SYMBOLS 1 ... Electrode paste (electrode ink), 2 ... Electrolyte membrane, 3, 30 ... 1st fixed roller, 4, 32 ... 2nd fixed roller, 5 ... Small diameter roller, 6 ... Electrolyte membrane roll for unwinding, 7 ... Rolled electrolyte membrane roll, 8 ... Die head, 9 ... Coating roller, 11 ... Paste coating part, 12 ... Straight line, 21 ... Fixed stage 21, 22, 31 ... Heating and drying furnace, 23, 33 ... Hygroscopic part 24 ... conveyor (moving means), 25 ... mounting table, 25a ... surface, 25b ... suction hole.

Claims (7)

A method for producing a membrane-electrode assembly for a fuel cell by coating an electrode layer on an electrolyte membrane of a solid polymer, the coating step of coating an electrode paste containing alcohol as a solvent on the electrolyte membrane, and this coating A drying process in which the electrolyte membrane coated with the electrode paste in the construction process is fixed to a fixing member and dried, and a moisture absorption process in which the electrolyte membrane absorbs moisture while fixing the electrolyte membrane dried in this drying process to the fixing member A process for producing a membrane electrode assembly for a fuel cell, comprising: 2. The method for producing a membrane electrode assembly for a fuel cell according to claim 1, wherein the moisture absorption step does not heat the electrolyte membrane and allows the electrolyte membrane to absorb moisture in the atmosphere. Manufacturing method of membrane electrode assembly. An apparatus for manufacturing a fuel cell membrane electrode assembly in which an electrode paste containing alcohol as a solvent is applied to a solid polymer electrolyte membrane to form an electrode layer, wherein the manufacturing device is applied to an electrolyte membrane A drying unit that dries the electrode paste, and a moisture absorption unit that absorbs moisture in the electrolyte membrane that has passed through the drying unit, and the drying unit is fixed to prevent the electrolyte membrane coated with the electrode paste from being deformed. A first fixing means and a drying means for drying the electrolyte membrane fixed to the first fixing means, and the moisture absorbing portion includes a second fixing means for fixing the dried electrolyte membrane so as not to be deformed. A fuel cell membrane electrode assembly manufacturing apparatus. 4. The apparatus for producing a membrane electrode assembly for a fuel cell according to claim 3, wherein the drying means is a heating and drying furnace, and the first fixing means is a fixing stage for fixing the electrolyte membrane to the surface of a flat mounting table. The fuel cell membrane electrode assembly is manufactured by using the first fixing means as the second fixing means, and moving means for moving the first fixing means from the heating and drying furnace to the moisture absorption section. apparatus. 4. The apparatus for manufacturing a membrane electrode assembly for a fuel cell according to claim 3, wherein the drying means is a heating and drying furnace, and the first fixing means and the second fixing means are provided with suction holes on the side surfaces thereof. A fixed roller for fixing the electrolyte membrane by vacuum suction from a hole, wherein the fixed roller of the first fixing means is provided in the heating and drying furnace, and the fixing roller of the second fixing means is the outside of the heating and drying furnace An apparatus for manufacturing a membrane electrode assembly for a fuel cell, which is provided in a moisture absorption part. 4. The fuel cell membrane electrode assembly manufacturing apparatus according to claim 3, wherein the first fixing means and the second fixing means are provided with suction holes on the side surfaces, and the electrolyte membrane is fixed by vacuum suction from the suction holes. A fixing roller that heats the fixing roller of the first fixing means, and the fixing roller of the second fixing means is provided with the moisture absorbing portion. An apparatus for manufacturing a membrane electrode assembly for a fuel cell. 7. The fuel cell membrane electrode assembly manufacturing apparatus according to claim 5, wherein a roller having a smaller diameter than the fixed roller is disposed between the fixed rollers, and the center of the small diameter roller is the center of the fixed roller. An apparatus for manufacturing a membrane electrode assembly for a fuel cell, which is located on a straight line passing through the center.

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