JP6709054B2 - Method for manufacturing electrolyte membrane/electrode structure with resin frame - Google Patents

Description

The present invention relates to a fuel cell including a stepped electrolyte membrane/electrode structure in which a solid polymer electrolyte membrane is sandwiched between a first electrode and a second electrode, and a resin frame member that surrounds the outer periphery of the stepped electrolyte membrane/electrode structure. TECHNICAL FIELD The present invention relates to a method for manufacturing an electrolyte membrane/electrode structure with a resin frame for use.

Generally, a polymer electrolyte fuel cell employs a solid polymer electrolyte membrane composed of a polymer ion exchange membrane. The fuel cell includes an electrolyte membrane/electrode structure (MEA) in which an anode electrode is arranged on one surface of a solid polymer electrolyte membrane and a cathode electrode is arranged on the other surface of the solid polymer electrolyte membrane. There is. The anode electrode and the cathode electrode each have a catalyst layer (electrode catalyst layer) and a gas diffusion layer (porous carbon).

The electrolyte membrane/electrode structure is sandwiched between separators (bipolar plates) to form a power generation cell (unit fuel cell). This power generation cell is used as, for example, a vehicle fuel cell stack by stacking a predetermined number of layers.

In the electrolyte membrane/electrode structure, one gas diffusion layer is set to have a plane dimension smaller than that of the solid polymer electrolyte membrane, and the other gas diffusion layer is set to have substantially the same plane dimension as the solid polymer electrolyte membrane. In some cases, a so-called stepped electrolyte membrane/electrode structure (stepped MEA) is configured. At that time, in order to reduce the amount of the relatively expensive solid polymer electrolyte membrane used and to protect the thin solid polymer electrolyte membrane having low strength, the MEA with a resin frame incorporating a resin frame member is adopted. Has been done.

As the MEA with a resin frame, for example, a method of manufacturing an electrolyte membrane/electrode structure with a resin frame for a fuel cell disclosed in Patent Document 1 is known. In this method for manufacturing an electrolyte membrane/electrode structure with a resin frame for a fuel cell, a resin frame member is provided so as to surround the solid polymer electrolyte membrane. Specifically, the resin frame member is provided with a thin-walled inner peripheral projection projecting to one gas diffusion layer side and encircling the outer periphery of the one gas diffusion layer. The outer edge portion of the electrolyte membrane is joined with an adhesive.

As a means for further strengthening the bonding between the resin frame member and the solid polymer electrolyte membrane, for example, it is known to perform plasma treatment on a portion of the surface of the resin frame member that comes into contact with the adhesive. ing. This resin frame member is generally made of a hydrophobic material and tends to have a lower surface free energy than that of the solid polymer electrolyte membrane. Therefore, the wettability of the resin frame member with respect to the adhesive is enhanced by subjecting the resin frame member to plasma treatment to increase the surface free energy thereof. As a result, the resin frame member and the adhesive can be effectively brought into contact with each other, so that the resin frame member and the solid polymer electrolyte membrane can be firmly bonded.

JP, 2013-98155, A

By the way, since the solid polymer electrolyte membrane often has a higher surface free energy than the untreated resin frame member as described above, no treatment for increasing the surface free energy is performed. However, by sufficiently increasing the surface free energy of the solid polymer electrolyte membrane, it is expected that the resin frame member and the solid polymer electrolyte membrane will be bonded more firmly. Therefore, it is considered that the solid polymer electrolyte membrane is subjected to the same surface treatment as that of the resin frame member, but it is difficult to increase the surface free energy of the solid polymer electrolyte membrane by such surface treatment.

If the surface free energy of the solid polymer electrolyte membrane is simply increased, it is conceivable to put the solid polymer electrolyte membrane in a wet state by steam humidification or the like, but this means is adopted for the following reason. Is difficult. That is, if humidification is performed with high-temperature steam or the like until the surface free energy of the solid polymer electrolyte membrane is sufficiently increased, the entire solid polymer electrolyte membrane will swell excessively. Therefore, there is a concern that wrinkles may occur in the solid polymer electrolyte membrane or peeling may occur between the cathode electrode or the anode electrode and the solid polymer electrolyte membrane. As a result, the solid polymer electrolyte membrane and the adhesive cannot be brought into good contact with each other, and eventually the resin frame member and the solid polymer electrolyte membrane cannot be firmly joined.

Further, the liquid water present on the surface of the solid polymer electrolyte membrane also hinders the contact between the solid polymer electrolyte membrane and the adhesive, making it difficult to bond the resin frame member and the solid polymer electrolyte membrane. To do.

From the above, no effective means has yet been found for increasing the surface free energy of the solid polymer electrolyte membrane, and thereby more firmly and stably joining the resin frame member and the solid polymer electrolyte membrane. ..

The present invention solves this kind of problem, and increases the surface free energy of the solid polymer electrolyte membrane to enable a solid and stable bonding of the solid polymer electrolyte membrane and the resin frame member. It is an object of the present invention to provide a method for producing an attached electrolyte membrane/electrode structure.

In order to achieve the above-mentioned object, the present invention provides a first electrode on one surface of a solid polymer electrolyte membrane and a second electrode on the other surface of the solid polymer electrolyte membrane. The planar dimension of the first electrode is set to a dimension larger than the planar dimension of the second electrode, and the stepped electrolyte membrane/electrode structure and the solid polymer electrolyte membrane are disposed outside the second electrode. A method for producing an electrolyte membrane/electrode structure with a resin frame for a fuel cell, comprising: a resin frame member that is bonded to an exposed surface via an adhesive; The step of contacting with water, and after containing the water inside the exposed surface of the solid polymer electrolyte membrane, the solid polymer electrolyte membrane is present on the exposed surface before the whole swells It is characterized by including a step of removing water, a step of applying an adhesive to the exposed surface, and a step of joining the exposed surface and the resin frame member via the adhesive.

Hereinafter, “water” refers to liquid water unless otherwise specified. In the present invention, by directly contacting the exposed surface with water at 40° C. or lower, the vicinity of the exposed surface of the solid polymer electrolyte membrane can be brought into a concentrated wet state. That is, it is possible to prevent the entire solid polymer electrolyte membrane from becoming excessively swollen. Therefore, even if the surface free energy of the exposed surface is increased, it is possible to avoid wrinkles in the solid polymer electrolyte membrane and peeling between the solid polymer electrolyte membrane and the first electrode or the like. As a result, the wettability of the exposed surface with respect to the adhesive can be improved, and the adhesive and the exposed surface can be brought into good contact with each other.

Further, water is contained inside the exposed surface of the solid polymer electrolyte membrane, and the water on the exposed surface is removed so that water does not exist on the exposed surface. Apply the coating. This makes it possible to prevent the adhesive and water from directly contacting each other on the exposed surface and obstructing the adhesion between the solid polymer electrolyte membrane and the resin frame member. The removal of water includes, for example, wiping off the water on the exposed surface with a water-absorbent sheet, blowing air, or naturally drying. That is, it suffices that water is not present on the exposed surface regardless of whether it is artificial or not.

Further, since the step of containing water inside the exposed surface of the solid polymer electrolyte membrane is performed after the step electrolyte membrane/electrode structure (step MEA) is manufactured, the step may be performed before the step MEA is manufactured. It is also possible to effectively strengthen the bond between the solid polymer electrolyte membrane and the resin frame member. That is, in the manufacturing process of the step MEA, for example, the first electrode and the second electrode are joined to the solid polymer electrolyte membrane by hot pressing, so that the solid polymer electrolyte membrane is dried by heating during the hot pressing. I have a concern.

Therefore, even if water is contained inside the exposed surface of the solid polymer electrolyte membrane before the manufacturing process of the step MEA, the exposed surface is dried and the surface free energy is reduced by the manufacturing process of the step MEA. There is a concern that it will fall. However, as described above, in the present invention in which the solid polymer electrolyte membrane contains water after the step MEA is manufactured, an adhesive is applied to the exposed surface in a state of compensating for the surface free energy decreased in the step MEA manufacturing. Can be coated.

From the above, according to the present invention, the surface free energy of the exposed surface of the solid polymer electrolyte membrane can be effectively increased, and thereby, the resin frame member and the solid polymer electrolyte membrane can be made more solid and stable. It becomes possible to join.

In the method of manufacturing an electrolyte membrane/electrode structure with a resin frame described above, it is preferable that in the step of removing the water, the water is wiped while being spread in the surface direction of the exposed surface. In this case, since the excess water on the exposed surface can be quickly removed while effectively containing water inside the exposed surface of the solid polymer electrolyte membrane, the resin frame can be attached more easily and efficiently. It becomes possible to manufacture an electrolyte membrane/electrode structure.

According to the present invention, by directly contacting the exposed surface with water at 40° C. or lower, it is possible to prevent the entire solid polymer electrolyte membrane from becoming excessively swollen. Further, by containing water in the inside of the exposed surface and leaving no water on the exposed surface, direct contact between the adhesive and water can be avoided. Furthermore, by including water inside the exposed surface of the solid polymer electrolyte membrane after manufacturing the step MEA, it is possible to supplement the surface free energy that has been reduced in the manufacturing of the step MEA. As a result, the surface free energy of the exposed surface can be increased and the wettability with respect to the adhesive can be effectively increased, and by this, the resin frame member and the solid polymer electrolyte membrane can be more firmly and stably bonded. Will be possible.

It is a principal part disassembled perspective explanatory view of the solid polymer type power generation cell in which the electrolyte membrane with resin frame and electrode structure to which the manufacturing method which concerns on embodiment of this invention is applied is incorporated. It is the II-II sectional view taken on the line in FIG. 1 of the said power generation cell. It is explanatory drawing which shows the state which made 40 degreeC or less water contact the exposed surface of the solid polymer electrolyte membrane of step MEA in the said manufacturing method. FIG. 4 is an explanatory view showing a state in which water existing on the exposed surface of the solid polymer electrolyte membrane of FIG. 3 is contained after the water is contained inside the exposed surface in the manufacturing method. It is explanatory drawing which shows the state which applied the adhesive agent to the exposed surface of FIG. 4 in the said manufacturing method. It is explanatory drawing of the process of joining an exposed surface and a resin frame member via the adhesive agent of FIG. 5 in the said manufacturing method.

As shown in FIGS. 1 and 2, a resin frame-attached electrolyte membrane/electrode structure 10 to which a manufacturing method according to an embodiment of the present invention is applied is a horizontally long (or vertically long) rectangular solid polymer power generation cell. 12 is incorporated. A fuel cell stack is configured by stacking the plurality of power generation cells 12 in, for example, the arrow A direction (horizontal direction) or the arrow C direction (gravitational direction). The fuel cell stack is mounted on a fuel cell electric vehicle (not shown) as a vehicle-mounted fuel cell stack, for example.

The power generation cell 12 sandwiches the resin frame-attached electrolyte membrane/electrode structure 10 between the first separator 14 and the second separator 16. The first separator 14 and the second separator 16 have a horizontally long (or vertically long) rectangular shape. The first separator 14 and the second separator 16 are composed of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate whose surface is subjected to surface treatment for corrosion prevention, a carbon member, or the like.

The rectangular resin frame-attached electrolyte membrane/electrode structure 10 includes a stepped electrolyte membrane/electrode structure (stepped MEA) 10a. The step MEA 10a includes, for example, a solid polymer electrolyte membrane (cation exchange membrane) 18 in which a thin film of perfluorosulfonic acid is impregnated with water, and an anode electrode (first electrode) 20 sandwiching the solid polymer electrolyte membrane 18 therebetween. And a cathode electrode (second electrode) 22. For the solid polymer electrolyte membrane 18, an HC (hydrocarbon)-based electrolyte may be used in addition to the fluorine-based electrolyte.

The cathode electrode 22 has a smaller plane dimension (outer dimension) than the solid polymer electrolyte membrane 18 and the anode electrode 20. Instead of the above configuration, the anode electrode 20 may be configured to have a smaller plane size than the solid polymer electrolyte membrane 18 and the cathode electrode 22. At that time, the anode electrode 20 becomes the second electrode and the cathode electrode 22 becomes the first electrode.

As shown in FIG. 2, the anode electrode 20 includes a first electrode catalyst layer 20a bonded to one surface 18a of the solid polymer electrolyte membrane 18 and a first gas diffusion layer stacked on the first electrode catalyst layer 20a. And layer 20b. The first electrode catalyst layer 20a and the first gas diffusion layer 20b have the same outer dimensions and are set to the same outer dimensions (or less than the same) as the solid polymer electrolyte membrane 18.

The cathode electrode 22 is provided with a second electrode catalyst layer 22a joined to the surface 18b of the solid polymer electrolyte membrane 18 and a second gas diffusion layer 22b laminated on the second electrode catalyst layer 22a. The second electrode catalyst layer 22a and the second gas diffusion layer 22b have the same plane size and are set to have a plane size smaller than that of the solid polymer electrolyte membrane 18. An exposed surface 18be exposed to the outside of the cathode electrode 22 is provided at the outer peripheral edge portion of the solid polymer electrolyte membrane 18 on the surface 18b side. As described below, the exposed surface 18be preferably has a contact angle with water of 40° or less of 87° to 104°.

The second electrode catalyst layer 22a and the second gas diffusion layer 22b are set to have the same plane dimension, but the plane dimension of the second electrode catalyst layer 22a is the plane dimension of the second gas diffusion layer 22b. It may have a larger dimension (or a smaller dimension) than the dimension.

The first electrode catalyst layer 20a is formed, for example, by uniformly coating the surface of the first gas diffusion layer 20b with porous carbon particles having a platinum alloy supported on the surface thereof. The second electrode catalyst layer 22a is formed, for example, by uniformly coating the surface of the second gas diffusion layer 22b with porous carbon particles having a platinum alloy supported on the surface.

The first gas diffusion layer 20b is formed of a microporous layer 20b(m) having porosity and conductivity, and a carbon layer 20b(c) such as carbon paper or carbon cloth. The second gas diffusion layer 22b is formed of a microporous layer 22b(m) having porosity and conductivity, and a carbon layer 22b(c) such as carbon paper or carbon cloth. The plane dimension of the second gas diffusion layer 22b is set smaller than the plane dimension of the first gas diffusion layer 20b. The first electrode catalyst layer 20a and the second electrode catalyst layer 22a are formed on the surfaces 18a and 18b of the solid polymer electrolyte membrane 18, respectively.

The resin frame-attached electrolyte membrane/electrode structure 10 goes around the outer periphery of the solid polymer electrolyte membrane 18 and is bonded to the outer peripheral surface of the solid polymer electrolyte membrane 18 in the form of a film-shaped resin frame member (resin molded body or resin molded body or resin molded body). Resin film) 24.

The resin frame member 24 is, for example, PPS (polyphenylene sulfide), PPA (polyphthalamide), PEN (polyethylene naphthalate), PES (polyether sulfone), LCP (liquid crystal polymer), PVDF (polyvinylidene fluoride), It is made of silicone resin, fluororesin, m-PPE (modified polyphenylene ether resin), or the like. The resin frame member 24 is further composed of PET (polyethylene terephthalate), PBT (polybutylene terephthalate), modified polyolefin, or the like.

The resin frame member 24 has a flat plate shape and is provided with an adhesive surface 24a that is joined to the exposed surface 18be of the solid polymer electrolyte membrane 18. An adhesive layer 26 is provided between the exposed surface 18be of the solid polymer electrolyte membrane 18 and the adhesive surface 24a of the resin frame member 24. The adhesive 26a that constitutes the adhesive layer 26 is not particularly limited, but it is preferable that the adhesive 26a have components similar to those of the solid polymer electrolyte membrane 18. That is, for example, when the solid polymer electrolyte membrane 18 is a fluorine-based electrolyte, the adhesive 26a preferably has a fluorine-based component. In this case, the solid polymer electrolyte membrane 18 and the resin frame member 24 can be bonded more favorably via the adhesive layer 26.

As shown in FIG. 1, one end edge portion of the power generation cell 12 in the arrow B direction (horizontal direction in FIG. 1) communicates with each other in the arrow A direction which is the stacking direction, and the oxidant gas inlet communication hole 30a, A cooling medium inlet communication hole 32a and a fuel gas outlet communication hole 34b are provided. The oxidant gas inlet communication hole 30a supplies an oxidant gas, for example, an oxygen-containing gas, while the cooling medium inlet communication hole 32a supplies a cooling medium. The fuel gas outlet communication hole 34b discharges a fuel gas, for example, a hydrogen-containing gas. The oxidant gas inlet communication hole 30a, the cooling medium inlet communication hole 32a, and the fuel gas outlet communication hole 34b are arranged in the direction of arrow C (vertical direction).

At the other end edge portion of the power generation cell 12 in the direction of arrow B, a fuel gas inlet communication hole 34a that communicates with each other in the direction of arrow A to supply a fuel gas, a cooling medium outlet communication hole 32b that discharges a cooling medium, and an oxidation An oxidant gas outlet communication hole 30b for discharging the agent gas is provided. The fuel gas inlet communication hole 34a, the cooling medium outlet communication hole 32b, and the oxidant gas outlet communication hole 30b are arranged in the arrow C direction.

On the surface 16a of the second separator 16 that faces the electrolyte membrane/electrode structure 10 with a resin frame, a plurality of members that communicate with the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b and extend in the direction of arrow B are provided. A book oxidant gas flow path 36 is provided.

On the surface 14a of the first separator 14 facing the electrolyte membrane/electrode structure 10 with a resin frame, there are provided a plurality of the plurality of members which communicate with the fuel gas inlet communication hole 34a and the fuel gas outlet communication hole 34b and extend in the arrow B direction. A fuel gas channel 38 is formed. Between the surface 14b of the first separator 14 and the surface 16b of the second separator 16, which are adjacent to each other, a plurality of communicating with the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b and extending in the arrow B direction. A book cooling medium channel 40 is formed.

As shown in FIGS. 1 and 2, the first seal member 42 is integrated with the surfaces 14 a and 14 b of the first separator 14 around the outer peripheral end of the first separator 14. The second seal member 44 is integrated with the surfaces 16a and 16b of the second separator 16 by encircling the outer peripheral end of the second separator 16.

As shown in FIG. 2, the first seal member 42 includes a first convex seal 42 a that abuts on the resin frame member 24 that constitutes the electrolyte frame-attached electrolyte membrane/electrode structure 10, and a second seal of the second separator 16. And a second convex seal 42b that abuts the member 44. The second seal member 44 constitutes a flat seal in which the surface in contact with the second convex seal 42b extends in a flat shape along the separator surface. A convex seal (not shown) may be provided on the second seal member 44 instead of the second convex seal 42b.

The first seal member 42 and the second seal member 44 are, for example, EPDM (ethylene propylene diene rubber), NBR (nitrile rubber), fluororubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene. Alternatively, a seal member having elasticity such as a seal material such as acrylic rubber, a cushion material, or a packing material is used.

Next, a manufacturing method according to the present embodiment for manufacturing the resin frame-attached electrolyte membrane/electrode structure 10 will be described below.

First, while the step MEA 10a is produced, the resin frame member 24 is injection molded using a mold (not shown), or a member obtained by cutting a film into a frame shape with a Thomson blade is prepared. In order to manufacture the step MEA 10a, first, a slurry made of a mixture of carbon black and PTFE (polytetrafluoroethylene) particles is applied to the flat surface of the carbon layer 20b(c) made of carbon paper, and dried to be dried. The microporous layer 20b(m), which is the stratum, is formed.

The first gas diffusion layer 20b is formed by joining the carbon layer 20b(c) to the microporous layer 20b(m). Similarly, the microporous layer 22b(m) is formed, and the carbon layer 22b(c) is bonded to the microporous layer 22b(m) to form the second gas diffusion layer 22b.

On the other hand, after adding a solvent to the electrode catalyst, for example, a solution of a perfluoroalkylsulfonic acid polymer compound is added as an ion conductive polymer binder solution. Then, the anode electrode ink and the cathode electrode ink are prepared by adding a solvent until the ink has a predetermined viscosity.

The anode electrode ink is applied to a PET film (not shown) by screen printing and dried by heating to form an anode electrode sheet (not shown) provided with the first electrode catalyst layer 20a. The first electrode catalyst layer 20a is set to have the same plane size as the solid polymer electrolyte membrane 18.

Similarly, the cathode electrode ink is applied to a PET film (not shown) by screen printing and heated and dried to form a cathode electrode sheet (not shown) provided with the second electrode catalyst layer 22a. It The second electrode catalyst layer 22a is set to have a plane dimension smaller than that of the solid polymer electrolyte membrane 18.

Next, hot pressing is performed with the solid polymer electrolyte membrane 18 sandwiched between the anode electrode sheet and the cathode electrode sheet. Then, the PET film is peeled off to form a bonded body (CCM) (catalyst coated membrane). Furthermore, the first gas diffusion layer 20b and the second gas diffusion layer 22b sandwich the CCM between the microporous layers 20b(m) and 22b(m) and are integrated by hot pressing to form the step MEA 10a. (See Figure 3). When the water contained in the solid polymer electrolyte membrane 18 is vaporized by hot pressing or the like in the manufacturing process of the step MEA 10a, the solid polymer electrolyte membrane 18 is dried, so that the surface free energy thereof tends to be lowered. ..

Next, liquid water 50 at 40° C. or lower is brought into contact with the exposed surface 18be of the step MEA 10a. For example, as shown in FIG. 3, water 50 at 40° C. or lower is maintained in a state of being dripped on the exposed surface 18be (particularly, the area where the adhesive 26a is applied). As a result, the vicinity of the exposed surface 18be of the solid polymer electrolyte membrane 18 can be concentrated in a wet state, and the water vaporized from the solid polymer electrolyte membrane 18 in the manufacturing process of the step MEA 10a can be supplemented. ..

That is, it is possible to increase the surface free energy of the exposed surface 18be while avoiding the state where the entire solid polymer electrolyte membrane 18 is swollen excessively. For this reason, wrinkles may occur in the solid polymer electrolyte membrane 18, or peeling may occur between the solid polymer electrolyte membrane 18 and the first electrode catalyst layer 20a of the anode electrode 20, that is, in the step MEA 10a. It is possible to avoid structural destruction. At this time, by setting the contact angle of the exposed surface 18be with the water 50 to be 87° or more, it is possible to further obtain the above-described action and effect. Further, by setting the contact angle to 104° or less, it is possible to more effectively suppress the occurrence of peeling between the solid polymer electrolyte membrane 18 and the first electrode catalyst layer 20a and the like.

After the water 50 is contained inside the exposed surface 18be of the solid polymer electrolyte membrane 18 as described above, the water 50 present on the exposed surface 18be is removed. Examples of methods for removing the water 50 on the exposed surface 18be include wiping with a water-absorbent sheet or the like, natural drying, blowing air, etc., but are not particularly limited thereto. Further, for example, from the viewpoint of effectively containing the water 50 in the solid polymer electrolyte membrane 18 and quickly removing the excess water 50 on the exposed surface 18be, the water 50 is pushed in the surface direction of the exposed surface 18be. It is preferable to wipe while spreading.

As shown in FIG. 4, the solid polymer electrolyte membrane 18 from which the water 50 on the exposed surface 18be is removed contains water 50 inside the exposed surface 18be, and the water 50 exists on the exposed surface 18be. It becomes a state not to do. Thereby, the surface free energy of the exposed surface 18be can be increased and the wettability with respect to the adhesive 26a can be improved. Further, as described above, since the structural breakage of the step MEA 10a is avoided, the wrinkles and the peeling portion of the solid polymer electrolyte membrane 18 do not hinder the contact between the exposed surface 18be and the adhesive 26a.

Therefore, as shown in FIG. 5, by coating the exposed surface 18be with the adhesive 26a, the exposed surface 18be and the adhesive 26a can be brought into good contact with each other. Further, the direct contact between the adhesive 26a and the water 50 on the exposed surface 18be is avoided, so that the adhesive force of the adhesive 26a can be satisfactorily exhibited.

Next, the exposed surface 18be and the adhesive surface 24a of the resin frame member 24 are bonded via the adhesive 26a. The adhesive surface 24a is preferably subjected to a surface treatment such as a plasma treatment in advance to enhance the surface free energy.

The method of joining the exposed surface 18be and the adhesive surface 24a may be appropriately selected according to the type of the adhesive 26a. For example, when the adhesive 26a is thermosetting, as shown in FIG. 6, the exposure surface 18be and the adhesive surface 24a are opposed to each other via the adhesive 26a and heated and pressed by the servo press machine 60. It suffices to perform processing. The servo press machine 60 includes a fixed base 62 and a movable base 64, and the movable base 64 can be moved back and forth with respect to the fixed base 62 by a piston 66.

From the above, according to the manufacturing method of the present embodiment, the surface free energy of the exposed surface 18be can be effectively increased, and thereby the resin frame member 24 and the solid polymer electrolyte membrane 18 are strongly bonded. It becomes possible to do.

The operation of the power generation cell 12 configured as above will be described below.

First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 30a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 34a. Supplied. Furthermore, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 32a.

Therefore, the oxidant gas is introduced into the oxidant gas flow path 36 of the second separator 16 through the oxidant gas inlet communication hole 30a, moves in the direction of arrow B, and is supplied to the cathode electrode 22 of the step MEA 10a. On the other hand, the fuel gas is introduced into the fuel gas passage 38 of the first separator 14 through the fuel gas inlet communication hole 34a. The fuel gas moves in the direction of arrow B along the fuel gas flow path 38 and is supplied to the anode electrode 20 of the step MEA 10a.

Therefore, in each step MEA 10a, the oxidant gas supplied to the cathode electrode 22 and the fuel gas supplied to the anode electrode 20 are electrochemically reacted in the second electrode catalyst layer 22a and the first electrode catalyst layer 20a. It is consumed and electricity is generated.

Next, the oxidant gas supplied to and consumed by the cathode electrode 22 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 30b. Similarly, the fuel gas supplied to the anode electrode 20 and consumed is discharged in the direction of arrow A along the fuel gas outlet communication hole 34b.

Further, the cooling medium supplied to the cooling medium inlet communication hole 32a is introduced into the cooling medium flow passage 40 between the first separator 14 and the second separator 16 and then flows in the direction of arrow B. This cooling medium is discharged from the cooling medium outlet communication hole 32b after cooling the step MEA 10a.

The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention.

[Fabrication of step MEA]
(1) As the carbon layers of the first gas diffusion layer and the second gas diffusion layer, a carbon paper “TGP-H060” (trade name) manufactured by Toray Industries, Inc. was cut out with a Thomson blade and used. Specifically, the planar shape of the carbon layer of the first gas diffusion layer was 230 mm×130 mm, and the planar shape of the carbon layer of the second gas diffusion layer was 200 mm×100 mm. The configurations of the first gas diffusion layer and the second gas diffusion layer other than the planar shapes were made in the same manner so that they are the same.

(2) A slurry in which carbon black and polytetrafluoroethylene (PTFE) particles were mixed at a weight ratio of 4:6 and uniformly dispersed in ethylene glycol was prepared as a paste for a microporous layer.

(3) The microporous layer paste prepared in (2) was applied to each flat surface of the carbon layer prepared in (1) and dried at 100° C. for 10 minutes. As a result, a first gas diffusion layer and a second gas diffusion layer in which the microporous layer was bonded to the carbon layer were obtained.

(4) In order to obtain the anode electrode ink, first, normal propyl alcohol (NPA) and water were mixed at a weight ratio of 1:2 to prepare a solvent. Next, this solvent was mixed with a platinum catalyst "TEC10EA50E" (trade name) manufactured by Tanaka Kikinzoku Co., Ltd. in a weight ratio of 10:1, and then the weight ratio of the platinum catalyst to the catalyst was 1:1. A conductive polymer binder solution was added and mixed until a predetermined ink viscosity was obtained. As the ion conductive polymer binder solution, a solution of a perfluoroalkylsulfonic acid polymer compound (for example, an ion conductive polymer solution “DE2020” (trade name) manufactured by DuPont) was used. Next, this mixed solution was stirred using a planetary ball mill at 80 rpm×120 minutes for homogenization to prepare an anode electrode ink.

(5) The anode electrode ink prepared in (4) above was screen-printed and applied on a PET film so that the weight of platinum was 0.2 mg/cm ^2, and after heating at 60° C. for 10 minutes, An anode electrode sheet was produced by heating at 100° C. for 15 minutes under reduced pressure and drying.

(6) In order to obtain the cathode electrode ink, first, NPA and water were mixed at a weight ratio of 1:2 to prepare a solvent. Next, this solvent was mixed with a platinum catalyst "TEC10EA50E" (trade name) manufactured by Tanaka Kikinzoku Co., Ltd. at a weight ratio of 10:1, and the weight ratio with the platinum catalyst was set to 1:1.5. The ion conductive polymer binder solution was added to and mixed until the ink had a predetermined viscosity. The same solution as in (4) above was used as the ion conductive polymer binder solution. Next, this mixed solution was stirred using a planetary ball mill at 80 rpm×120 minutes for homogenization to prepare a cathode electrode ink.

(7) The cathode electrode ink prepared in (6) above was screen-printed and applied on a PET film so that the weight of platinum was 0.5 mg/cm ^2, and after heating at 60° C. for 10 minutes, A cathode electrode sheet was produced by heating at 100° C. for 15 minutes under reduced pressure and drying.

(8) A solid polymer electrolyte membrane is sandwiched so as to be in contact with the ink coated surface of the anode electrode sheet prepared in (5) and the ink coated surface of the cathode electrode sheet prepared in (7), and 120° C. Hot pressing was performed for 8 minutes under the condition of 2.0 MPa. As the solid polymer electrolyte membrane, Nafion "NRE-211" (trade name) manufactured by DuPont was used. Then, the PET films of the anode electrode sheet and the cathode electrode sheet were peeled off to prepare a CCM.

(9) The CCM prepared in (8) is sandwiched between the microporous layers of the first gas diffusion layer and the second gas diffusion layer prepared in (3), and the conditions are 120° C. and 2.0 MPa. Then, hot pressing was performed for 12 minutes to integrate them. At this time, the load absorbing material was arranged on the second gas diffusion layer side. After that, the outer peripheral portion of the first gas diffusion layer was punched out with a Thomson blade to perform trimming, thereby producing a step MEA having a maximum planar shape of 210 mm×110 mm.

[Production of resin frame member]
(10) A resin frame member was produced by cutting a Toray PPS sheet “Torelina 5000” (trade name) having a thickness of 250 μm into a frame shape with a Thomson blade.

(11) Plasma treatment is applied to the adhesive surface of the resin frame member prepared in (10) for 30 seconds using a plasma device “YAP-510” (trade name) manufactured by Yamato Scientific Co., Ltd. Went quality.

[Preparation of electrolyte membrane/electrode structure with resin frame]
[Example 1]
(12) In an environment of ambient temperature; 23° C., relative humidity (RH); 50%, 30° C. water is dropped on the exposed surface of the solid polymer electrolyte membrane of the step MEA prepared in (9) above. After contacting for 2 minutes, it was wiped off while being spread by a hygroscopic sheet.

(13) On the exposed surface of the solid polymer electrolyte membrane in the step MEA, a fluorine-based adhesive "SIFEL2661" (trade name) manufactured by Shin-Etsu Chemical Co., Ltd., a dispenser "ML-606GX" (trade name) manufactured by Musashi Engineering Co., Ltd. Used for coating. At this time, the width of the adhesive was set to 1 mm, and while the adhesive was brought into contact with the end surface of the second gas diffusion layer, the outer periphery was circulated.

(14) Fix a servo press made by Shinto Kogyo Co., Ltd. via a PTFE sheet with a superposed body in which a step MEA and a resin frame member are superposed so that the adhesive surface is brought into contact with the adhesive agent applied to the exposed surface. It was held between the base and the movable base. Then, a heating/pressurizing process of heating at 140° C. and applying a load of 500 N was performed for 12 minutes. In this way, the adhesive was cured to form an adhesive layer, and a resin frame-attached electrolyte membrane/electrode structure in which a resin frame member was joined to the step MEA via the adhesive layer was obtained. This is Example 1.

[Example 2]
In the step (12), the temperature of water dropped on the exposed surface of the step MEA is 40° C. instead of 30° C., and otherwise the same as in Example 1 in the same manner as in Example 1 with a resin frame-attached electrolyte membrane/electrode structure. Got This is Example 2.

[Example 3]
In the step (12), the time for contacting the water dropped on the exposed surface of the step MEA is changed from 2 minutes to 5 minutes, and otherwise the same as in Example 1 in the same manner as in Example 1 with a resin frame-attached electrolyte membrane/electrode. The structure was obtained. This is Example 3.

[Comparative Example 1]
In the step (12), the temperature of water dropped on the exposed surface of the step MEA was set to 50°C instead of 30°C. Other than that was carried out in the same manner as in Example 1 to obtain an electrolyte membrane/electrode structure with a resin frame of Comparative Example 1. In this case, wrinkles, a first electrode catalyst layer, etc. were formed on the solid polymer electrolyte membrane. Was peeled off, and the structure of the step MEA was destroyed. That is, it was not possible to satisfactorily obtain an electrolyte membrane/electrode structure with a resin frame.

[Comparative example 2]
Instead of the step of (12), the step MEA produced in (9) was steam humidified for 2 minutes in a constant temperature/humidity bath. At this time, the temperature in the constant temperature/constant humidity tank was set to 30° C., and the relative humidity (RH) was set to 90%. Otherwise in the same manner as in Example 1, an electrolyte membrane-electrode structure with a resin frame was obtained. This is Comparative Example 2.

[Comparative Example 3]
Instead of the step of (12), the step MEA produced in (9) was steam humidified for 2 minutes in a constant temperature/humidity bath. At this time, the temperature in the constant temperature/humidity bath was set to 40° C., and the relative humidity (RH) was set to 90%. Other than that, in the same manner as in Example 1, an attempt was made to obtain a resin frame-equipped electrolyte membrane/electrode structure of Comparative Example 3, but in this case as well, structural breakdown of the step MEA occurred, resulting in resin frame-equipped electrolyte membrane/electrode. The structure could not be obtained well.

[Comparative Example 4]
Instead of the step of (12), the step MEA produced in (9) was steam humidified for 2 minutes in a constant temperature/humidity bath. At this time, the temperature inside the constant temperature and humidity chamber was set to 50° C., and the relative humidity (RH) was set to 90%. Other than that was carried out in the same manner as in Example 1 to obtain an electrolyte membrane/electrode structure with a resin frame of Comparative Example 4, but in this case as well, structural destruction of the step MEA occurred and an electrolyte membrane/electrode with a resin frame was formed. The structure could not be obtained well.

[Comparative Example 5]
Instead of the step of (12), the step MEA produced in (9) was steam humidified for 2 minutes in a constant temperature/humidity bath. At this time, the temperature inside the constant temperature and humidity chamber was set to 60° C., and the relative humidity (RH) was set to 90%. Other than that, in the same manner as in Example 1, an attempt was made to obtain an electrolyte membrane/electrode structure with a resin frame of Comparative Example 5, but in this case as well, structural breakdown of the step MEA occurred, resulting in an electrolyte membrane/electrode with a resin frame. The structure could not be obtained well.

[Comparative Example 6]
Instead of the step of (12), the step MEA produced in (9) was steam humidified for 2 minutes in a constant temperature/humidity bath. At this time, the temperature inside the constant temperature and humidity chamber was set to 40° C., and the relative humidity (RH) was set to 80%. Other than that, in the same manner as in Example 1, an attempt was made to obtain a resin frame-attached electrolyte membrane/electrode structure of Comparative Example 6, but in this case as well, structural breakdown of the step MEA occurred, and the resin frame-attached electrolyte membrane/electrode was formed. The structure could not be obtained well.

[Comparative Example 7]
Instead of the step (12), the step MEA produced in (9) was steam humidified for 15 seconds in a constant temperature/humidity bath. At this time, the temperature in the constant temperature/humidity bath was set to 40° C., and the relative humidity (RH) was set to 90%. Otherwise in the same manner as in Example 1, an electrolyte membrane-electrode structure with a resin frame was obtained. This is Comparative Example 7.

[Comparative Example 8]
Instead of the step (12), the step MEA produced in (9) was steam humidified for 30 seconds in a constant temperature/humidity bath. At this time, the temperature in the constant temperature/humidity bath was set to 40° C., and the relative humidity (RH) was set to 90%. Other than that, in the same manner as in Example 1, an attempt was made to obtain a resin frame-attached electrolyte membrane/electrode structure of Comparative Example 8. In this case as well, structural breakdown of the step MEA occurred, and resin frame-attached electrolyte membrane/electrode structure was produced. The structure could not be obtained well.

[Comparative Example 9]
An electrolyte membrane/electrode structure with a resin frame was obtained in the same manner as in Example 1 except that the step (12) was omitted. That is, Comparative Example 9 is an electrolyte membrane/electrode structure with a resin frame, which was produced without subjecting the exposed surface of the step MEA to any humidification treatment.

The resin frame-attached electrolyte membrane/electrode structures of Examples 1 to 3 and the resin frame-attached electrolyte membrane/electrode structures of Comparative Examples 2, 7 and 9 in which the structural breakage of the step MEA did not occur were each 180 A peel test in the direction of degree was performed. In this peeling test, first, test pieces were prepared from each of the resin frame-attached electrolyte membrane/electrode structures of Examples 1 to 3 and Comparative Examples 2, 7, and 9.

Specifically, the exposed surface of the solid polymer electrolyte membrane and the adhesive surface of the resin frame member are bonded to each other via the adhesive layer to have a width of 2 cm and a length of 5 cm. I cut it out. Then, after the first gas diffusion layer was peeled off from the solid polymer electrolyte membrane, the second gas diffusion layer was further peeled off. As a result, a test piece composed of a joined body of the resin frame member and CCM was produced. In the same manner, 40 test pieces were produced for each of the resin frame-attached electrolyte membrane/electrode structures of Examples 1 to 3 and Comparative Examples 2, 7, and 9.

Next, the resin frame member side of the test piece is held at one end of the applied test apparatus “Autograph AGS-J” (trade name) manufactured by Shimadzu Corporation, and the CCM side of the test piece is held at the other end, and 180 The peel strength in the degree direction was measured.

For each of the resin frame-attached electrolyte membrane/electrode structures of Examples 1 to 3 and Comparative Examples 2, 7, and 9, the difference between the average peel strength of 40 test pieces and the smallest peel strength was calculated as above. The value divided by the average value was obtained as the variation rate (%). That is, the smaller the variation rate, the stronger and stably the exposed surface and the adhesive surface are joined together. Table 1 shows the rate of change obtained for each of the resin frame-attached electrolyte membrane/electrode structures of Examples 1 to 3 and Comparative Examples 2, 7, and 9. In addition, Table 1 also shows the respective production conditions of the electrolyte membrane-attached electrolyte membrane/electrode structures of Examples 1 to 3 and Comparative Examples 1 to 9 and whether or not structural breakdown of the step MEA occurred in the production process. Shown together.

From Table 1, it was found that in steam humidification in a constant temperature/constant humidity tank, structural failure occurs in the step MEA when the temperature in the tank exceeds 30° C. and the humidification time exceeds 15 seconds. That is, when steam humidification is performed under the above conditions, the solid polymer electrolyte membrane is entirely humidified and becomes excessively swollen, which may lead to structural destruction of the step MEA.

It was also found that structural damage occurs in the step MEA when the water contacting the exposed surface exceeds 40°C. Therefore, it was found that by contacting the exposed surface with water at 40° C. or lower, it is possible to prevent the entire solid polymer electrolyte membrane from becoming excessively swollen.

Further, from Table 1, the fluctuation ratios of Examples 1 to 3 are higher than the fluctuation ratios of Comparative Examples 2 and 7 in which no structural destruction occurs in the step MEA and Comparative Example 9 in which the exposed surface is not humidified. It was found to be less than 1/3. That is, it is considered that the steam humidification treatment under the conditions of Comparative Examples 2 and 7 could not perform sufficient humidification to increase the surface free energy of the exposed surface. Further, in Comparative Example 9, it is considered that the solid polymer electrolyte membrane was dried by the hot pressing or the like performed when the step MEA was manufactured, and the surface free energy of the exposed surface was lowered.

On the other hand, in Examples 1 to 3, it is possible to sufficiently increase the surface free energy of the exposed surface without excessively swelling the solid polymer electrolyte membrane, and thereby the solid polymer electrolyte membrane and the resin frame member. It was possible to make the joint with and strong and stable.

10... Electrolyte Membrane/Electrode Structure with Resin Frame 10a... Step MEA
12... Power generation cell 14, 16... Separator 18... Solid polymer electrolyte membrane 18be... Exposed surface 20... Anode electrode 20a... First electrode catalyst layer 20b... First gas diffusion layer 22... Cathode electrode 22a... Second electrode catalyst layer 22b ...Second gas diffusion layer 24...resin frame member 24a...adhesive surface 26...adhesive layer 26a...adhesive 50...water

Claims (4)

A first electrode is provided on one surface of the solid polymer electrolyte membrane, a second electrode is provided on the other surface of the solid polymer electrolyte membrane, and the planar dimension of the first electrode is the second dimension. A stepped electrolyte membrane/electrode structure set to a size larger than the planar size of the electrode,
A resin frame member joined to the exposed surface of the solid polymer electrolyte membrane exposed to the outside of the second electrode via an adhesive;
A method for manufacturing an electrolyte membrane/electrode structure with a resin frame for a fuel cell having:
Contacting the exposed surface with liquid water at 40° C. or lower,
After containing the water inside the exposed surface of the solid polymer electrolyte membrane , removing the water present on the exposed surface before the entire solid polymer electrolyte membrane swells ,
A step of applying an adhesive to the exposed surface,
Bonding the exposed surface and the resin frame member via the adhesive,
A method for producing an electrolyte membrane/electrode structure with a resin frame, comprising: The first electrode is provided on one surface of the solid polymer electrolyte membrane, the second electrode is provided on the other surface of the solid polymer electrolyte membrane, and the planar dimension of the first electrode is the second dimension. A stepped electrolyte membrane/electrode structure set to a size larger than the planar size of the electrode,
A resin frame member joined to the exposed surface of the solid polymer electrolyte membrane exposed to the outside of the second electrode via an adhesive;
A method for manufacturing an electrolyte membrane/electrode structure with a resin frame for a fuel cell having:
Contacting the exposed surface with liquid water at 40° C. or lower,
After containing the water inside the exposed surface of the solid polymer electrolyte membrane, the water present on the exposed surface before the water reaches the back surface of the exposed surface of the solid polymer electrolyte membrane The step of removing
A step of applying an adhesive to the exposed surface,
Bonding the exposed surface and the resin frame member via the adhesive,
A method for producing an electrolyte membrane/electrode structure with a resin frame, comprising: The first electrode is provided on one surface of the solid polymer electrolyte membrane, the second electrode is provided on the other surface of the solid polymer electrolyte membrane, and the planar dimension of the first electrode is the second dimension. A stepped electrolyte membrane/electrode structure set to a size larger than the planar size of the electrode,
A resin frame member joined to the exposed surface of the solid polymer electrolyte membrane exposed to the outside of the second electrode via an adhesive;
A method for manufacturing an electrolyte membrane/electrode structure with a resin frame for a fuel cell having:
Contacting the exposed surface with liquid water at 40° C. or lower,
After the water is contained inside the exposed surface of the solid polymer electrolyte membrane, the water existing on the exposed surface is removed before the contact angle of the exposed surface with water exceeds 104°. The process of
A step of applying an adhesive to the exposed surface,
Bonding the exposed surface and the resin frame member via the adhesive,
A method for producing an electrolyte membrane/electrode structure with a resin frame, comprising: The method for producing an electrolyte membrane/electrode structure with a resin frame according to claim 1, wherein
In the step of removing the water, the water is wiped while being spread in the surface direction of the exposed surface, and the method for producing an electrolyte membrane/electrode structure with a resin frame.

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