JP2009224279A - Manufacturing method of assembly for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce electric resistance between a separator and a gas diffusion layer (GDL) while restraining damage on an electrolyte membrane caused by an object eluted out from an adhesive. <P>SOLUTION: A water-repellent material as a fixing material is impregnated into a substrate 44 forming a gas diffusion layer 42, the substrate 44 is brought into contact with the surface on a reaction gas passage 35 (36) side of the separator 20, and the substrate 44 and the separator 20 are integrated with each other by drying them up at an existing state. It is preferable to use a coated material of the separator 20 or the same kind of a material with the gas diffusion layer 42 as a fixing material. Furthermore, it is preferable to dry up the substrate 44 from both surfaces on the gas passage 35 (36) side and the other side of the separator 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a fuel cell assembly. More specifically, the present invention relates to an improvement in a method for manufacturing an assembly constituting a fuel cell.

  In general, a fuel cell (for example, a polymer electrolyte fuel cell) includes a joined body (eg, MEA, MEGA) composed of an electrolyte membrane and a pair of electrodes disposed on both sides thereof, and a reaction gas flow path that sandwiches the joined body. It comprises a pair of separators provided. In addition, a plurality of such cells are stacked to form a so-called fuel cell stack.

  Conventionally, when manufacturing assemblies for fuel cells including these assemblies and separators, a separator and a gas diffusion layer (GDL) are manufactured separately, and contact resistance is reduced by applying pressure and pressure. There is a technique. In some cases, the separator and the gas diffusion layer are bonded with a conductive adhesive to reduce the resistance (for example, see Patent Documents 1 and 2).

Further, in a separator in which a fluid flow path that bends in the middle like a so-called serpentine type is formed, gas leakage may easily occur at the turn portion. Therefore, conventionally, a separator and a gas diffusion layer are fixed using an adhesive or a thermosetting resin to suppress gas leakage at the portion (see, for example, Patent Documents 1 and 3).
Japanese Patent Laid-Open No. 2004-6306 JP 2001-85019 A JP 2005-166597 A

  However, there is a limit to reducing contact resistance by pressurization. Further, when a conductive adhesive is used, contamination by different materials (for example, contamination caused by elution components in the fuel cell, etc., hereinafter also referred to as contamination) may occur, and other members may be deteriorated. There is.

  Also, in conventional cells, the adhesive is exposed to a high temperature and strongly acidic environment during power generation of the fuel cell, so that an eluate may be generated from the adhesive, and among these eluates, particularly Si (silicon) is generated. It is a problem that the contained substance causes damage such as film cracking to the electrolyte membrane.

  Accordingly, the present invention provides an assembly for a fuel cell in which the electrical resistance between the separator and the gas diffusion layer (GDL) can be reduced while preventing the electrolyte membrane from being damaged by the effluent from the adhesive or the like. It aims at providing the manufacturing method of.

  In order to solve this problem, the present inventor has made various studies. When pressure is applied to the separator and the gas diffusion layer as in the past, fibers on the surface of the gas diffusion layer may pierce the MEA, causing cross leaks and cell short circuits. Pressure must be avoided. Further, if a fuel cell structure without a humidifying module is established in the future, it is necessary to further reduce the thickness of the electrolyte membrane, which may further limit the applied pressure. In addition, in the first place, there is a limit to achieving reduction in contact resistance between the separator, which is a separate member, and the gas diffusion layer by pressurization.

  Further, although a silicon-containing resin is used as a material having excellent adhesive strength, if this silicon elutes in a high-temperature and strongly acidic environment, it may be taken into the electrolyte membrane and deteriorate the electrolyte membrane.

  The inventor who has further studied these points has come up with an idea that leads to the solution of such a problem. The present invention is based on such an idea, and includes a separator having a reaction gas flow path, and a method of manufacturing a fuel cell assembly including a gas diffusion layer for diffusing the reaction gas flowing in the flow path toward the electrolyte membrane. The base material forming the gas diffusion layer is impregnated with a water repellent material, the base material is brought into contact with the surface of the separator on the reaction gas flow path side, and the base material and the separator are integrated by drying in that state. I try to make it.

  According to such a method for manufacturing a fuel cell assembly, the gas diffusion layer (GDL) and the separator can be integrated and assembled without being pressurized. In the case of the present invention, there is a limit in reducing the contact resistance when the gas diffusion layer and the separator are integrated by pressure and pressure bonding as in the past, but in the case of the present invention, the water repellent impregnated in the base material Since the gas diffusion layer and the separator are integrated using the material, the contact resistance can be sufficiently reduced.

  Moreover, in the present invention, since the water repellent material impregnated in the base material is used in this way, it is possible to suppress the occurrence of contamination as in the case of using a different material (for example, a conductive adhesive).

  In such a method for producing a fuel cell assembly, a water repellent material can be applied and impregnated on a base material, and the base material can be placed on the surface of the separator on the reaction gas flow path side and dried in that state. In this case, since the base material is placed on the separator in an undried state containing the water repellent material, the water repellent material easily spreads over the unevenness of the separator surface without any gaps and is easily adapted.

  It is also preferred to dry the substrate from both the flow path side surface of the separator and the opposite surface. In particular, if heat is applied to the placed substrate from the lower surface side, the gas flow path of the separator is blocked, resulting in pressure loss (due to the shape of the fluid flow path, the smoothness of the surface of the fluid flow path, etc. This is preferable in that it is easy to avoid a situation where energy such as pressure of the fluid is consumed).

  The present invention also provides a method of manufacturing an assembly for a fuel cell, comprising a separator having a reaction gas flow path, and a gas diffusion layer for diffusing the reaction gas flowing in the flow path toward the electrolyte membrane. The water-repellent material used in the diffusion layer is used as a fixing material, the fixing material is applied between a portion where the gas diffusion layer is formed and the separator, the fixing material is dried, and the separator, the diffusion layer and the fixing material are fixed. The material is integrated to secure the fixing force.

  According to this manufacturing method, since the gas diffusion layer and the separator are integrated using the water repellent material used for the gas diffusion layer, the contact resistance can be sufficiently reduced without applying pressure or pressure bonding. Is possible. In addition, since the water repellent material used for the gas diffusion layer is used as the fixing material in this way, it is possible to suppress the occurrence of contamination as in the case of using a different material (for example, a conductive adhesive).

  In this case, it is preferable to use the same kind of material as the separator coating material or gas diffusion layer as the fixing agent.

  Moreover, it is preferable to apply the fixing agent to the turn portion of the reaction gas flow path in the separator or in the vicinity thereof. According to this, in the separator in which the gas flow path has a serpentine shape, it is possible to suppress leakage particularly at a portion where the reaction gas easily leaks.

  Furthermore, the present invention is a method for producing an assembly for a fuel cell comprising a separator having a reaction gas flow path and a gas diffusion layer for diffusing the reaction gas flowing in the flow path toward the electrolyte membrane, The water-repellent material used in the diffusion layer is used as a fixing material, the fixing material is applied to a predetermined portion between the part where the gas diffusion layer is formed and the separator, and the applied fixing agent is locally applied by annealing. It is to heat and weld.

  In this manufacturing method, since the gas diffusion layer and the separator are integrated using the water repellent material used for the gas diffusion layer, the contact resistance can be sufficiently reduced without applying pressure or pressure bonding. Is possible. In addition, since the water repellent material used for the gas diffusion layer is used as the fixing material in this way, it is possible to suppress the occurrence of contamination as in the case of using a different material (for example, a conductive adhesive).

  In this case, the fixing agent is preferably applied to the turn portion of the reaction gas flow path in the separator or in the vicinity thereof.

  According to the present invention, the electrical contact resistance (cell resistance) between the separator and the gas diffusion layer (GDL) is reduced while suppressing the electrolyte membrane from being damaged by the effluent from the adhesive or the like. Can do. Therefore, it is possible to improve the output of the fuel cell.

  Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings.

  1 to 12 show an embodiment of the present invention. In the embodiment described below, first, a schematic configuration of a fuel cell stack in which a cell (power generation cell) 2 and a plurality of cells 2 constituting the fuel cell 1 are stacked will be described, and then a fuel cell assembly The manufacturing method will be described.

  FIG. 1 shows a schematic configuration of a cell 2 of a fuel cell 1 in the present embodiment. The cells 2 configured as shown in the figure are sequentially stacked to form a cell stack 3 (see FIG. 2). Further, in the fuel cell stack composed of the cell stack 3 or the like, for example, both ends of the stack are sandwiched between a pair of end plates 7, and a restraining member including a tension plate 8 is disposed so as to connect the end plates 7 to each other. In this state, a load in the stacking direction is applied and fastened (see FIG. 2).

  The fuel cell 1 configured by such a fuel cell stack or the like can be used in, for example, an in-vehicle power generation system of a fuel cell vehicle (FCHV; Fuel Cell Hybrid Vehicle), but is not limited thereto. It can also be used in power generation systems mounted on various mobile bodies (for example, ships, airplanes, etc.), self-propelled devices such as robots, and stationary power generation systems.

  As an electrolyte contained in the cell 2, a membrane-electrode assembly (MEA) or a membrane-electrode-diffusion layer assembly (MEGA) can be used. For example, in this embodiment, a membrane-electrode-diffusion layer assembly (hereinafter also referred to as MEGA) 30 is used (see FIG. 1 and the like).

  The cell 2 includes a MEGA 30 and a pair of separators 20 (indicated by reference numerals 20a and 20b in FIG. 1 and the like) that sandwich the MEGA 30 (see FIG. 1). The MEGA 30 and the separators 20a and 20b are formed in a substantially rectangular plate shape. The MEGA 30 is formed so that its outer shape is smaller than the outer shapes of the separators 20a and 20b.

  The MEGA 30 includes a polymer electrolyte membrane (hereinafter also simply referred to as an electrolyte membrane) 31 made of a polymer material ion exchange membrane, and a pair of electrodes (an anode side diffusion electrode and a cathode side diffusion electrode) sandwiching the electrolyte membrane 31 from both sides. 32, 33 (see FIG. 1). The electrolyte membrane 31 is formed larger than the electrodes 32 and 33. The electrodes 32 and 33 are joined to the electrolyte membrane 31 by, for example, a hot press method with the peripheral edge 34 left.

  The electrodes 32 and 33 constituting the MEGA 30 are made of, for example, porous carbon materials (diffusion layers 32b and 33b) carrying a catalyst such as platinum attached to the surface thereof. One electrode (anode) 32 is supplied with hydrogen gas as a fuel gas (reactive gas), and the other electrode (cathode) 33 is supplied with an oxidizing gas (reactive gas) such as air or an oxidizing agent. An electrochemical reaction is generated in the MEGA 30 by the gas, so that an electromotive force of the cell 2 can be obtained.

  The gas diffusion layer (indicated by reference numeral 42 in FIG. 5) is a layer formed so as to diffuse the reaction gas supplied to the electrolyte membrane 31 appropriately. For example, the gas diffusion layer 42 in the present embodiment is formed smaller than the electrolyte membrane 31 (and the electrodes 32 and 33). Further, the gas diffusion layer 42 and the electrolyte membrane 31 (and the electrodes 32 and 33) are in a state where their peripheral portions (portions close to the periphery) are sandwiched by the frame member 40.

  The separator 20 (20a, 20b) is made of a gas impermeable conductive material. Examples of the conductive material include carbon and a hard resin having conductivity, and metals such as aluminum and stainless steel. The base material of the separator 20 (20a, 20b) of the present embodiment is formed of a plate-like metal (metal separator), and a film with excellent corrosion resistance is provided on the surface of the base material on the electrode 32, 33 side. (For example, a film formed by gold plating) is formed.

  Further, a groove-like flow path constituted by a plurality of concave portions is formed on both surfaces of the separators 20a and 20b. These flow paths can be formed by press molding in the case of the separators 20a and 20b of the present embodiment in which the base material is formed of, for example, a plate-like metal. The groove-like flow path formed in this way constitutes a gas flow path 35 for oxidizing gas, a gas flow path 36 for hydrogen gas, or a cooling water flow path 37. More specifically, a gas channel 36 for hydrogen gas is formed on the inner surface of the separator 20a on the electrode 32 side, and a cooling water channel 37 is formed on the back surface (outer surface) ( (See FIG. 1). Similarly, an oxidizing gas flow channel 35 is formed on the inner surface of the separator 20b on the electrode 33 side, and a cooling water flow channel 37 is formed on the back surface (outer surface) (see FIG. 1). . For example, in the case of the present embodiment, regarding the two adjacent cells 2, 2, when the outer surface of the separator 20 a of one cell 2 and the outer surface of the separator 20 b of the cell 2 adjacent to this are combined, The channel 37 is integrated to form a channel having a rectangular or honeycomb cross section.

  Furthermore, as described above, the separators 20a and 20b have a relationship in which at least the uneven shape for forming a fluid flow path is reversed between the front surface and the back surface. More specifically, in the separator 20a, the back surface of the convex shape (convex rib) forming the hydrogen gas gas flow path 36 is a concave shape (concave groove) forming the cooling water flow path 37, and the gas flow path The back surface of the concave shape (concave groove) forming 36 is a convex shape (convex rib) forming the cooling water channel 37. Further, in the separator 20 b, the back surface of the convex shape (convex rib) that forms the gas flow path 35 of the oxidizing gas has a concave shape (concave groove) that forms the cooling water flow path 37, and the concave that forms the gas flow path 35. The back surface of the shape (concave groove) is a convex shape (convex rib) forming the cooling water channel 37.

  Further, in the vicinity of the longitudinal ends of the separators 20a and 20b (in the case of this embodiment, in the vicinity of one end shown on the left side in FIG. 1), the manifold 15a on the inlet side of the oxidizing gas, hydrogen gas An outlet side manifold 16b and a cooling water inlet side manifold 17a are formed. For example, in the case of this embodiment, these manifolds 15a, 16b, and 17a are formed by substantially rectangular or trapezoidal holes provided in the respective separators 20a and 20b, or long and thin rectangular through holes having semicircular ends (FIG. 1). Etc.). Furthermore, a manifold 15b on the outlet side of the oxidizing gas, a manifold 16a on the inlet side of hydrogen gas, and a manifold 17b on the outlet side of the cooling water are formed at opposite ends of the separators 20a and 20b. In the case of this embodiment, these manifolds 15b, 16a, and 17b are also formed by a substantially rectangular or trapezoidal shape or a long and narrow rectangular through hole having semicircular ends (see FIG. 1).

  Of the manifolds as described above, the inlet side manifold 16a and the outlet side manifold 16b for the hydrogen gas in the separator 20a are connected via the inlet side communication passage 61 and the outlet side communication passage 62 formed in the separator 20a. Each communicates with a gas flow path 36 for hydrogen gas. Similarly, the inlet side manifold 15a and the outlet side manifold 15b for the oxidizing gas in the separator 20b are each formed of an oxidizing gas via an inlet side connecting passage 63 and an outlet side connecting passage 64 formed in the separator 20b. It communicates with the flow path 35 (see FIG. 1). Further, the inlet side manifold 17a and the outlet side manifold 17b of the cooling water in each separator 20a, 20b are respectively connected via an inlet side communication passage 65 and an outlet side communication passage 66 formed in each separator 20a, 20b. It communicates with the cooling water flow path 37. With the configuration of the separators 20a and 20b as described above, the cell 2 is supplied with oxidizing gas, hydrogen gas, and cooling water. As a specific example, when the cells 2 are stacked, for example, hydrogen gas passes from the inlet side manifold 16a of the separator 20a through the communication passage 61 and flows into the gas flow path 36, and is supplied to the MEGA 30 for power generation. After that, the fluid passes through the communication passage 62 and flows out to the outlet side manifold 16b.

  In the present embodiment, the cooling water inlet side manifold 17a and the outlet side manifold 17b are arranged on one side and on the other side of the separator 20 in the cooling water flow direction, respectively (see FIG. 1). That is, in this embodiment, the inlet side manifold 17a and the outlet side manifold 17b of the cooling water are arranged on the diagonal line of the separator 20 so that the cooling water can easily spread over the separator 20 over the entire surface. .

  The first seal member 13a and the second seal member 13b are provided as necessary (see FIG. 1). When provided between the separators 20a and 20b, the first seal member 13a and the second seal member 13b are, for example, both a plurality of members (for example, four independent small rectangular frames to form a fluid flow path. (See FIG. 1). Among these, the first seal member 13a is provided between the MEGA 30 and the separator 20a. More specifically, a part of the first seal member 13a is a peripheral portion 34 of the electrolyte membrane 31 and a gas flow path 36 of the separator 20a. It is provided so that it may interpose between the surrounding parts. The second seal member 13b is provided between the MEGA 30 and the separator 20b. More specifically, a part of the second seal member 13b includes the peripheral edge 34 of the electrolyte membrane 31 and the gas flow path 35 of the separator 20b. It is provided so as to be interposed between the surrounding portions.

  Further, a plurality of members (for example, four independent small rectangular frames and a large frame for forming a fluid flow path) are formed between the separators 20b and 20a of the adjacent cells 2 and 2. A third seal member 13c is provided (see FIG. 1). The third seal member 13c is provided so as to be interposed between a portion around the cooling water passage 37 in the separator 20b and a portion around the cooling water passage 37 in the separator 20a, and seals between them. It is.

  In addition, as the first to third seal members 13a to 13c, an elastic body (gasket) that seals a fluid by physical contact with an adjacent member, or an adhesive that is bonded by chemical bonding with an adjacent member. An agent or the like can be used. For example, in this embodiment, a member that is physically sealed by elasticity is employed as each of the seal members 13a to 13c, but instead, a member that is sealed by a chemical bond such as the adhesive described above may be employed.

  The frame member (hereinafter also referred to as a resin frame) 40 is a member (hereinafter also referred to as a resin frame) made of, for example, resin that is sandwiched between the MEGA 30 and the separators 20a and 20b. For example, in the present embodiment, a thin frame-shaped resin frame 40 is interposed between the separators 20a and 20b, and at least a part of the MEGA 30 such as a portion along the peripheral edge 34 is sandwiched from the front side and the back side by the resin frame 40. I have to. The resin frame 40 provided in this way functions as a spacer between the separators 20 (20a, 20b) that supports the fastening force, functions as an insulating member, and as a reinforcing member that reinforces the rigidity of the separator 20 (20a, 20b). Demonstrate the function.

  Next, the configuration of the fuel cell 1 will be briefly described (see FIG. 2). The fuel cell 1 according to the present embodiment includes a cell stack 3 formed by stacking a plurality of cells 2, and sequentially heat-insulating cells outside the cells (end cells) 2 and 2 located at both ends of the cell stack 3. 4 and a terminal plate 5 with an output terminal 5a, an insulator (insulating plate) 6, and an end plate 7. A predetermined compressive force in the stacking direction is applied to the cell stack 3 by a tension plate 8 that is bridged so as to connect both end plates 7. Further, a pressure plate 9 and a spring mechanism 9a are provided between the end plate 7 on one end side of the cell stack 3 and the insulator 6, so that the fluctuation of the load acting on the cell 2 is absorbed. ing.

  The heat insulation cell 4 has a heat insulation layer formed of, for example, two separators and a seal member, and plays a role of suppressing heat generated by power generation to be radiated to the atmosphere. That is, in general, since the temperature of the end of the cell stack 3 is likely to be lowered by heat exchange with the atmosphere, heat exchange (heat dissipation) is suppressed by forming a heat insulating layer on the end of the cell stack 3. Has been done. As such a heat insulating layer, for example, there is a structure in which a heat insulating member 10 such as a conductive plate is sandwiched between a pair of separators similar to those in the cell 2 instead of the membrane-electrode assembly. The heat insulating member 10 used in this case is more suitable as it has better heat insulating properties. Specifically, for example, a conductive porous sheet or the like is used. Moreover, an air layer is formed by sealing the circumference | surroundings of such a heat insulation member 10 with a sealing member.

  The terminal plate 5 is a member that functions as a current collecting plate, and is formed in a plate shape from a metal such as iron, stainless steel, copper, or aluminum. The surface of the terminal plate 5 on the heat insulating cell 4 side is subjected to a surface treatment such as a plating treatment, and the contact resistance with the heat insulating cell 4 is ensured by the surface treatment. Examples of the plating include gold, silver, aluminum, nickel, zinc, tin, and the like. For example, in this embodiment, tin plating is performed in consideration of conductivity, workability, and low cost.

  The insulator 6 is a member that functions to electrically insulate the terminal plate 5 from the end plate 7 and the like. In order to fulfill such a function, the insulator 6 is formed in a plate shape from a resin material such as polycarbonate.

  The end plate 7 is formed in a plate shape with various metals (iron, stainless steel, copper, aluminum, etc.) like the terminal plate 5. For example, in the present embodiment, the end plate 7 is formed using copper, but this is merely an example, and the end plate 7 may be formed of another metal.

  The tension plate 8 is provided so as to bridge between the end plates 7 and 7 and is disposed so that, for example, a pair is opposed to both sides of the cell stack 3 (see FIG. 2). The tension plate 8 is fixed to the end plates 7 and 7 with bolts or the like, and maintains a state in which a predetermined fastening force (compression force) is applied in the stacking direction of the single cells 2. An insulating film is formed on the inner surface of the tension plate 8 (the surface facing the cell stack 3) in order to prevent leakage or sparks. Specifically, the insulating film is formed by, for example, an insulating tape attached to the inner surface of the tension plate 8 or a resin coating applied so as to cover the surface.

  Then, the manufacturing method of the assembly for fuel cells concerning this invention is demonstrated (refer FIG. 3 etc.). This manufacturing method includes a separator 20 having a reaction gas channel (oxidation gas gas channel 35 or hydrogen gas gas channel 36) and a reaction gas channel (oxidation gas gas channel 35 or hydrogen gas channel 36). The present invention is suitable for application to a fuel cell assembly including a gas diffusion layer 42 for diffusing a reactive gas (oxidizing gas, hydrogen gas) flowing through the gas flow path 36) toward the electrolyte membrane 31.

<First Embodiment>
In the present embodiment, a base material (indicated by reference numeral 44 in FIG. 3) that forms the gas diffusion layer 42 is impregnated with a water-repellent paste (water-repellent material) 45, and the base material 44 is reacted with the reaction gas flow path of the separator 20. The substrate 44 and the separator 20 are integrated by bringing them into contact with the surface on the side of the gas flow path 35 of oxidizing gas or the gas flow path 36 of hydrogen gas and drying in that state (FIG. 3). (See FIG. 5).

  An example of the procedure of the method for manufacturing the fuel cell assembly is as follows. That is, first, the substrate 44 is impregnated by applying a water repellent paste 45 or the like (see FIG. 3). In the present embodiment, the base material 44 is impregnated with the water repellent paste 45 used in the gas diffusion layer 42 and is also used as a fixing material.

  Next, the base material 44 impregnated with the water repellent paste 45 is placed on the surface of the separator 20 on the side of the reaction gas channel (oxidation gas gas channel 35 or hydrogen gas gas channel 36) (FIG. 4). (See Fig.), And dry in that state. At this time, the substrate 44 impregnated with the water repellent paste 45 is placed on the separator 20 in an undried state, whereby the water repellent paste 45 is placed on the surface of the separator (specifically, a reaction gas flow path (oxidizing gas) The gas flow path 35 or the hydrogen gas flow path 36)) can be spread and become familiar.

  Subsequently, the base material 44 is dried, and the base material 44 and the separator 2 are integrated (see FIG. 5). At this time, at least the surface of the separator 20 on the side of the reaction gas flow path (oxidation gas gas flow path 35 or hydrogen gas gas flow path 36) is dried by applying heat or the like. It is preferable. In particular, if heat is applied to the substrate 44 placed on the separator 20 from the lower surface side, the reaction gas flow path (oxidation gas gas flow path 35 or hydrogen gas gas flow path 36) of the separator 20 is provided. It is easy to avoid the situation that the pressure loss increases due to blockage. Note that “pressure loss” in the present specification means that energy such as pressure of the fluid is consumed due to the shape of the fluid channel, the smoothness of the surface of the fluid channel, and the like.

  According to the above manufacturing method, a fuel cell assembly (indicated by reference numeral 50 in FIG. 5 and the like) composed of the separator 20 and the gas diffusion layer 42 can be manufactured. Moreover, according to such a manufacturing method, the gas diffusion layer 42 (or the base material 44 forming the gas diffusion layer 42) and the separator 20 can be integrated and assembled without applying pressure. When the gas diffusion layer 42 and the separator 20 are integrated by pressure and pressure bonding as in the conventional case, there is a limit in reducing the contact resistance. Since the gas diffusion layer 42 (or the base material 44 on which the gas diffusion layer 42 is formed) and the separator 20 are integrated using the water repellent paste 45, it is possible to sufficiently reduce the contact resistance. In the present embodiment, the water-repellent paste 45 originally used in the gas diffusion layer 42 is also used as a fixing material, so that the occurrence of contamination as in the case of using a different material (for example, a conductive adhesive) is suppressed. be able to.

<Second Embodiment>
In the present embodiment, a water repellent paste (water repellent material) 45 used for partitioning a predetermined region in the gas diffusion layer 42 is used as a fixing material, and the fixing material is used to form the gas diffusion layer 42. And the separator 20 are dried, and the fixing material is dried, and the separator 20, the gas diffusion layer 42, and the fixing material are integrated to secure the fixing force.

  An example of the procedure of the method for manufacturing the fuel cell assembly is as follows. That is, first, the water-repellent paste 45 used for the gas diffusion layer 42 is used as a fixing material and applied to a predetermined position on the gas diffusion layer of the MEGA 30 (see FIG. 6). At this time, if the water-repellent paste 45 is applied to the vicinity of the edge of the MEGA 30 so as to be in contact with the resin frame 40 as in this embodiment, these members including the resin frame 40 can be assembled (see FIG. 6). ). The direction in which the water-repellent paste 45 is applied may be the vertical direction or the horizontal direction.

  Here, it is preferable to use the same material as the coating material of the separator 20 or the same material as the gas diffusion layer 42 as the fixing material. If, for example, a carbon coating material is used as the coating material of the separator 20, it is preferable to use the carbon material (carbon paste) as a fixing material, whereby a predetermined degree of adhesive strength (adhesion strength) can be obtained. . Further, when the water repellent paste 45 used for the gas diffusion layer 42 is used as a fixing material, unnecessary components may be removed in advance as the fixing material.

  Next, the separator 20 and the MEGA 30 (and the resin frame 40) are overlaid so that the water-repellent paste 45 is also attached to a part of the surface of the separator 20 (see FIG. 7). In this assembled state, the fixing material is dried, the paste solvent is removed from the fixing material, and the gas diffusion layer 42 and the separator 20 (for example, the carbon coating material of the separator 20) are fixed (see FIG. 8).

  According to the above manufacturing method, the separator 20, the MEGA 30, and the resin frame 40 can be assembled with the fixing material. Moreover, according to such a manufacturing method, the separator 20 and the like can be integrated and assembled without being pressurized. For example, when the separator 20 and the MEGA 30 are integrated by pressurization and pressure bonding as in the conventional case, there is a limit in reducing the contact resistance. Since the separator 20 and the MEGA 30 are integrated using the paste 45, the contact resistance can be sufficiently reduced. In the present embodiment, the water-repellent paste 45 originally used in the gas diffusion layer 42 is also used as a fixing material, so that the occurrence of contamination as in the case of using a different material (for example, a conductive adhesive) is suppressed. be able to.

  When the fuel cell 1 is a serpentine type, a fixing agent is applied to the turn portion of the reaction gas flow path (oxidation gas gas flow path 35 or hydrogen gas gas flow path 36) in the separator 20 or in the vicinity thereof. It is preferable. In the case of the serpentine type, the reaction gas flow path (oxidation gas gas flow path 35 or hydrogen gas flow path 36) is formed so that the reaction gas spreads over the entire surface while turning. Reactant gas leakage may occur. In this regard, as described above, if a fixing material is applied to a predetermined portion (particularly a portion outside the bent portion) in the turn portion or in the vicinity thereof, leakage at a portion where the reactive gas easily leaks can be suppressed. it can. FIG. 9 shows a schematic diagram of the gas flow path 36 of the hydrogen gas in the serpentine separator 20 for reference. Symbols S and T in the figure represent a straight portion and a turn portion of the gas flow path 36, respectively (see FIG. 9).

<Third Embodiment>
In the present embodiment, the water-repellent paste (water-repellent material) 45 used in the gas diffusion layer 42 is used as a fixing material, and the fixing material is used between the part where the gas diffusion layer 42 is formed and the separator 20. The applied fixing agent is locally heated and welded by laser annealing.

  An example of the procedure of the method for manufacturing the fuel cell assembly is as follows. That is, first, the water-repellent paste 45 used for the gas diffusion layer 42 is used as a fixing material and applied to a predetermined position on the gas diffusion layer of the MEGA 30 (see FIG. 10). At this time, if the fixing material is applied to the vicinity of the edge of the MEGA 30 so as to be in contact with the resin frame 40 as in the present embodiment, these members including the resin frame 40 can be assembled (see FIG. 10).

  Here, it is preferable to use the same material as the coating material of the separator 20 or the same material as the gas diffusion layer 42 as the fixing material. Further, when the water repellent paste 45 used for the gas diffusion layer 42 is used as a fixing material, unnecessary components may be removed in advance as the fixing material. In addition, as a fixing material, it is also possible to use a material (for example, polyimide) that is excellent in adhesive strength, high temperature resistance, and chemical resistance and is cured at a high temperature at 200 ° C. or higher.

  Next, the separator 20 and the MEGA 30 (and the resin frame 40) are overlapped with each other so that the fixing material is attached to a part of the surface of the separator 20 (see FIG. 11). Further, in the assembled state as described above, the fixing material is locally heated by, for example, heat treatment (annealing treatment) by laser annealing (see FIG. 12). In such a case, the fixing material can be heated and melted while the damage to other parts is suppressed, and the separator 20 and the like can be welded.

  According to the above manufacturing method, the separator 20, the MEGA 30, and the resin frame 40 can be assembled with the fixing material. Moreover, according to such a manufacturing method, the separator 20 and the like can be integrated and assembled without being pressurized. For example, when the separator 20 and the MEGA 30 are integrated by pressure and pressure bonding as in the conventional case, there is a limit in reducing the contact resistance, but in the present embodiment, the water repellent paste 45 is used. As a result, the contact resistance can be sufficiently reduced and the occurrence of contamination can be suppressed. When the fuel cell 1 is a serpentine type, a sticking agent is applied to the turn part of the reaction gas flow path (oxidation gas gas flow path 35 or hydrogen gas gas flow path 36) in the separator 20 or in the vicinity thereof. This is also preferable as in the above-described embodiment.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the present embodiment, laser annealing has been described as an example of annealing, but other than that, annealing processing using an electron beam, a lamp, or the like is naturally possible.

It is a disassembled perspective view which shows the structural example of the cell of the fuel cell in this embodiment. It is a side view which shows the structural example of a fuel cell. In the 1st Embodiment of this invention, it is a figure which shows a mode that a water-repellent paste is apply | coated to a base material. It is a figure which shows a mode that the base material impregnated with the water repellent paste was mounted in the surface at the side of the reaction gas flow path of a separator. It is a figure which shows a mode that a base material is dried and integrated with the separator. It is a figure which shows a mode that a water repellent paste is apply | coated to the predetermined position on the gas diffusion layer of MEGA in the 2nd Embodiment of this invention. It is a figure which shows a mode that the separator and MEGA were piled up and water-repellent paste was made to adhere also to a part of surface of the said separator. It is a figure which shows a mode that it dried and the gas diffusion layer and the separator were adhere | attached. It is the schematic which illustrates the gas flow path of the hydrogen gas in a serpentine type separator. It is a figure which shows a mode that a fixing material is apply | coated to the predetermined position on the gas diffusion layer of MEGA in the 3rd Embodiment of this invention. It is a figure which shows a mode that the separator and MEGA were piled up and the adhering material was made to adhere also to a part of surface of the said separator. It is a figure which shows a mode that a fixing material is heated locally by the heat processing by laser annealing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 20 (20a, 20b) ... Separator, 30 ... MEGA, 31 ... Polymer electrolyte membrane (electrolyte membrane), 31 ... Electrolyte membrane, 35 ... Gas flow path of oxidizing gas (reaction gas flow path), 36: Hydrogen gas gas flow path (reaction gas flow path), 42: Gas diffusion layer, 44: Base material (base material for forming the gas diffusion layer), 45: Water repellent paste (water repellent material), 50 ... Fuel cell assembly, T ... turn part

Claims (9)

A fuel cell assembly manufacturing method comprising: a separator having a reaction gas flow path; and a gas diffusion layer for diffusing the reaction gas flowing through the flow path toward an electrolyte membrane,
The base material forming the gas diffusion layer is impregnated with a water-repellent material, the base material is brought into contact with the surface of the separator on the side of the reaction gas flow path, and the base material and the separator are integrated by drying in that state. A method of manufacturing an assembly for a fuel cell, characterized by comprising:   2. The fuel cell assembly according to claim 1, wherein a water repellent material is applied and impregnated on the base material, and the base material is placed on the surface of the separator on the reaction gas flow path side and dried in that state. Method.   The manufacturing method of the assembly for fuel cells of Claim 1 or 2 which dries the said base material from the both surfaces of the said flow path side surface of the said separator, and its opposite surface. A fuel cell assembly manufacturing method comprising: a separator having a reaction gas flow path; and a gas diffusion layer for diffusing the reaction gas flowing through the flow path toward an electrolyte membrane,
The water-repellent material used in the gas diffusion layer is used as a fixing material, the fixing material is applied between a portion where the gas diffusion layer is formed and the separator, the fixing material is dried, and the separator A method for producing an assembly for a fuel cell, wherein the diffusion layer and the fixing material are integrated to secure a fixing force.   The method for manufacturing a fuel cell assembly according to claim 4, wherein the fixing agent is the same material as the coating material of the separator or the gas diffusion layer.   The method for producing a fuel cell assembly according to claim 4 or 5, wherein the fixing agent is applied to a turn portion of the reaction gas flow path in the separator or in the vicinity thereof. A fuel cell assembly manufacturing method comprising: a separator having a reaction gas flow path; and a gas diffusion layer for diffusing the reaction gas flowing through the flow path toward an electrolyte membrane,
The water-repellent material used in the gas diffusion layer is used as a fixing material, and the fixing material is applied to a predetermined portion between the part where the gas diffusion layer is formed and the separator, and the applied fixing agent A method of manufacturing a fuel cell assembly, wherein the fuel cell is locally heated and welded by annealing.   The method for manufacturing an assembly for a fuel cell according to claim 7, wherein the fixing agent is applied to a turn portion of the reaction gas flow path in the separator or in the vicinity thereof.   The fuel cell containing the assembly for fuel cells manufactured by the manufacturing method as described in any one of Claims 1-8.

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