JP6084181B2 - Method for producing hot melt adhesive - Google Patents

Description

  The present invention relates to a method for producing a hot melt adhesive having a frame shape for joining a resin frame member to an outer periphery of an electrolyte membrane / electrode structure in which electrodes are provided on both sides of the electrolyte membrane.

  In general, a polymer electrolyte fuel cell employs a polymer electrolyte membrane made of a polymer ion exchange membrane. This fuel cell comprises an electrolyte membrane / electrode structure in which an anode electrode and a cathode electrode each comprising a catalyst layer (electrode catalyst layer) and a gas diffusion layer (porous carbon) are disposed on both sides of a solid polymer electrolyte membrane ( MEA). The electrolyte membrane / electrode structure is sandwiched between separators (bipolar plates) to constitute a fuel cell. A fuel cell is used as, for example, an in-vehicle fuel cell stack by stacking a predetermined number of fuel cells to form a fuel cell stack.

  In the electrolyte membrane / electrode structure, a resin frame member is incorporated in order to reduce the amount of a relatively expensive solid polymer electrolyte membrane used and to protect the solid polymer electrolyte membrane having a thin film shape and low strength. A framed MEA is employed.

  For example, the electrolyte membrane / electrode structure with a resin frame for a fuel cell disclosed in Patent Document 1 includes a step MEA and a resin frame member. In the step MEA, a first electrode and a second electrode each having an electrode catalyst layer and a gas diffusion layer are provided on both sides of the solid polymer electrolyte membrane, and the first electrode has an outer dimension larger than that of the second electrode. It is set small. On the other hand, the resin frame member has an inner peripheral end that protrudes to the outer peripheral side of the first electrode and contacts the outer peripheral edge of the solid polymer electrolyte membrane, and the outer peripheral edge and the inner peripheral end are bonded to each other. It is adhered by the agent layer.

JP2013-98155A

  By the way, in said patent document 1, as an adhesive which adhere | attaches the joining site | part of the outer peripheral edge part of a solid polymer electrolyte membrane, and the inner peripheral edge part of a resin frame member, a hot melt adhesive agent may be used, for example. is there.

  At that time, the joint portion has a frame shape. For this reason, a long sheet-like hot melt adhesive (hereinafter referred to as a sheet-like adhesive) has been manufactured in advance, and the center and end of the sheet-like adhesive are trimmed to form a hot melt adhesive having a frame shape. The agent is obtained.

  However, since the hot-melt adhesive having a frame shape is cut out from the sheet-like adhesive, a large amount of hot-melt adhesive that is discarded may be generated. Therefore, there is a problem that it is not economical and the entire operation becomes complicated.

  The present invention solves this type of problem, can reduce the amount of hot melt adhesive to be discarded as much as possible, and can manufacture the hot melt adhesive economically and efficiently. An object of the present invention is to provide a method for producing a hot melt adhesive.

  The present invention relates to a method for producing a hot melt adhesive having a frame shape for joining a resin frame member to an outer periphery of an electrolyte membrane / electrode structure in which electrodes are provided on both sides of the electrolyte membrane.

  In this manufacturing method, a frame-shaped member is formed by preparing a mold apparatus having a frame-shaped slit that can be opened and closed by a shutter, and extruding a liquid hot-melt adhesive material from the frame-shaped slit by opening the shutter. It has a process. The molded frame-shaped member is dried.

  Moreover, in this manufacturing method, it is preferable that the inner peripheral part and outer peripheral part of the dried frame-shaped member are trimmed.

  According to the present invention, by opening the shutter of the mold apparatus, the liquid hot melt adhesive material is extruded from the frame-shaped slit, and the frame-shaped member is formed. And the hot-melt-adhesive which has a frame shape is obtained only by drying a frame-shaped member. Therefore, it is possible to reduce the amount of discarded hot melt adhesive as much as possible, and it is possible to manufacture the hot melt adhesive economically and efficiently.

It is a principal part disassembled perspective explanatory view of a polymer electrolyte fuel cell. FIG. 2 is a sectional view of the fuel cell taken along line II-II in FIG. 1. It is an isometric view explanatory drawing of the manufacturing system used for the manufacturing method concerning this embodiment. It is side surface explanatory drawing of the said manufacturing system. It is front explanatory drawing of the said manufacturing system. It is a perspective explanatory view showing the inside of a mold device which constitutes the manufacturing system. It is a perspective explanatory view of the hot melt adhesive manufactured by the manufacturing system. It is operation | movement explanatory drawing at the time of opening the shutter which comprises the said manufacturing system, and shape | molding a frame-shaped member. It is explanatory drawing of the state by which the said shutter was obstruct | occluded and the said frame-shaped member was cut away. It is explanatory drawing when the said frame shape member is conveyed. It is explanatory drawing of the adhesion | attachment operation | work by the said hot melt adhesive.

  As shown in FIGS. 1 and 2, a polymer electrolyte fuel cell 10 includes an electrolyte membrane / electrode structure 14 with a resin frame in which a hot melt adhesive 12 manufactured by the manufacturing method according to the present invention is used. . The plurality of fuel cells 10 are stacked in, for example, an arrow A direction (horizontal direction) or an arrow C direction (gravity direction) to form a fuel cell stack. The fuel cell stack is mounted on, for example, a fuel cell electric vehicle (not shown) as an in-vehicle fuel cell stack.

  In the fuel cell 10, the electrolyte membrane / electrode structure 14 with a resin frame is sandwiched between a cathode separator 16 and an anode separator 18. The cathode-side separator 16 and the anode-side separator 18 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, a metal plate whose surface is subjected to anticorrosion treatment, a carbon member, or the like.

  As shown in FIG. 2, the electrolyte membrane / electrode structure 14 with a resin frame includes an electrolyte membrane / electrode structure 14 a that is a step MEA. The electrolyte membrane / electrode structure 14 a includes, for example, a solid polymer electrolyte membrane 19 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode electrode 20 and a cathode electrode 22 sandwiching the solid polymer electrolyte membrane 19. Have. The solid polymer electrolyte membrane 19 uses an HC (hydrocarbon) electrolyte in addition to a fluorine electrolyte.

  The anode electrode 20 has a smaller planar dimension than the solid polymer electrolyte membrane 19 and the cathode electrode 22. The anode electrode 20 and the cathode electrode 22 may have the same planar dimension, and the cathode electrode 22 may have a smaller planar dimension than the anode electrode 20.

  The anode electrode 20 is disposed on one surface 19a of the solid polymer electrolyte membrane 19, and exposes the outer peripheral edge portion 19e of the solid polymer electrolyte membrane 19 in a frame shape. The cathode electrode 22 is disposed over the other surface 19 b of the solid polymer electrolyte membrane 19.

  The anode electrode 20 is provided with an electrode catalyst layer 20a bonded to the surface 19a of the solid polymer electrolyte membrane 19, and a gas diffusion layer 20b laminated on the electrode catalyst layer 20a. The cathode electrode 22 includes an electrode catalyst layer 22a bonded to the surface 19b of the solid polymer electrolyte membrane 19, and a gas diffusion layer 22b stacked on the electrode catalyst layer 22a.

  The electrode catalyst layers 20a and 22a are formed by uniformly applying porous carbon particles carrying a platinum alloy on the surfaces thereof to the surfaces of the gas diffusion layers 20b and 22b. The gas diffusion layers 20b and 22b are made of carbon paper or the like, and the plane dimension of the gas diffusion layer 20b is set smaller than the plane dimension of the gas diffusion layer 22b. The electrode catalyst layers 20a and 22a are formed on both surfaces 19a and 19b of the solid polymer electrolyte membrane 19, for example.

  As shown in FIGS. 1 and 2, the resin frame-attached electrolyte membrane / electrode structure 14 circulates around the outer periphery of the solid polymer electrolyte membrane 19 and is joined to the anode electrode 20 and the cathode electrode 22. Is provided. The resin frame member 24 includes, for example, PPS (polyphenylene sulfide), PPA (polyphthalamide), PEN (polyethylene naphthalate), PES (polyethersulfone), LCP (liquid crystal polymer), PVDF (polyvinylidene fluoride), It is composed of silicone rubber, fluorine rubber, EPDM (ethylene propylene rubber), m-PPE (modified polyphenylene ether resin), or the like.

  The resin frame member 24 has an inner peripheral end portion 24 a that protrudes toward the outer peripheral side of the anode electrode 20 and contacts the outer peripheral edge portion 19 e of the solid polymer electrolyte membrane 19. The inner peripheral end 24a has the same thickness as the anode electrode 20, substantially the same thickness as the gas diffusion layer 20b (when the intermediate layer is provided on the gas diffusion layer 20b, Including the thickness of the intermediate layer).

  The inner peripheral edge 24a of the resin frame member 24 and the outer peripheral edge 19e of the solid polymer electrolyte membrane 19 are bonded by a hot-melt adhesive 12 having an ester-based, acrylic-based, or urethane-based frame shape. The melting temperature of the hot melt adhesive 12 is, for example, 150 ° C. to 170 ° C., and the melting temperature of the resin frame member 24 is, for example, 360 ° C. The hot melt adhesive 12 is formed in a frame shape over the entire circumference of the outer peripheral edge portion 19 e of the solid polymer electrolyte membrane 19. The resin frame member 24 and the gas diffusion layer 22b of the cathode electrode 22 may be integrated by, for example, a resin impregnated portion (not shown).

  As shown in FIG. 1, one end edge of the fuel cell 10 in the direction of arrow A (horizontal direction in FIG. 1) communicates with each other in the direction of arrow B, which is the stacking direction. 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 fuel gas, for example, 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).

  The other end edge of the fuel cell 10 in the direction of arrow A communicates with each other in the direction of arrow B, the fuel gas inlet communication hole 34a for supplying fuel gas, the cooling medium outlet communication hole 32b for discharging the cooling medium, and the oxidation An oxidant gas outlet communication hole 30b for discharging the oxidant 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 direction of arrow C.

  An oxidant gas flow path 36 communicating with the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b is provided on the surface 16a of the cathode separator 16 facing the electrolyte membrane / electrode structure 14 with a resin frame. .

  A fuel gas flow path 38 communicating with the fuel gas inlet communication hole 34a and the fuel gas outlet communication hole 34b is formed on the surface 18a of the anode separator 18 facing the electrolyte membrane / electrode structure 14 with a resin frame. A cooling medium flow path 40 communicating with the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b is formed between the surface 18b of the anode side separator 18 and the surface 16b of the cathode side separator 16 adjacent to each other. .

  As shown in FIGS. 1 and 2, the first seal member 42 is integrated with the surfaces 18 a and 18 b of the anode separator 18 around the outer peripheral end of the anode separator 18. The second seal member 44 is integrated with the surfaces 16 a and 16 b of the cathode side separator 16 around the outer peripheral end of the cathode side separator 16.

  As shown in FIG. 2, the first seal member 42 includes a first convex seal 42a that contacts the inner peripheral end 24a of the resin frame member 24 constituting the electrolyte membrane / electrode structure 14 with a resin frame, and a cathode side. And a second convex seal 42b that contacts the second seal member 44 of the separator 16. The second seal member 44 constitutes a planar seal that extends in a planar shape along the separator surface. Instead of the second convex seal 42b, the second seal member 44 may be provided with a convex seal (not shown).

  The first and second sealing members 42 and 44 include, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber, a cushioning material, Alternatively, an elastic seal member such as a packing material is used.

  As shown in FIG. 1, the anode-side separator 18 has a supply hole portion 46 that communicates the fuel gas inlet communication hole 34a with the fuel gas passage 38, and the fuel gas passage 38 communicates with the fuel gas outlet communication hole 34b. A discharge hole 48 is formed.

  Next, a method for manufacturing the resin membrane-attached electrolyte membrane / electrode structure 14 will be described below.

  First, the electrolyte membrane / electrode structure 14a which is the step MEA is manufactured, and the resin frame member 24 is molded by injection molding using a mold (not shown). The resin frame member 24 integrally has a thin inner peripheral end 24a.

  On the other hand, the hot melt adhesive 12 having a frame shape is manufactured by the manufacturing system 50 according to the first embodiment shown in FIGS. The manufacturing system 50 includes a mold apparatus 52 and a conveyor 54.

  The mold device 52 includes a mold member 56 that is largely open on one end (bottom) side, and a cylindrical portion 58 is integrally provided on the other end (upper) side of the mold member 56. A liquid hot melt adhesive material 62 is introduced from the cylindrical portion 58 into the cavity 60 inside the mold member 56.

  As shown in FIGS. 6 and 7, the cavity 60 has an opening size corresponding to the outer peripheral shape 12 a of the hot melt adhesive 12. In the cavity 60, a plurality of core members 64, for example, four suspension members (may be bolts) 66 are arranged. The core member 64 has a cubic shape, and has an outer dimension corresponding to the inner peripheral shape 12 b of the hot melt adhesive 12. The cavity 60 forms a frame-shaped slit 60s by the core member 64 (see FIGS. 4 and 6).

  As shown in FIGS. 3 to 5, one or more, for example, two shutters 68 a and 68 b are disposed at the bottom of the mold member 56 so as to freely open and close the cavity 60 along the guide rails 70 a and 70 b. . The guide rails 70a and 70b extend in the long side direction (or short side direction) and are fixed to the lower end position of each long side (or short side) of the mold member 56. The shutters 68a and 68b are connected to the drive units 72a and 72b.

  The drive unit 72a includes a cylinder 74a that is fixed to one long side of the mold member 56 (not shown) and extends in the horizontal direction. The rod 76a protruding from the cylinder 74a is connected to the fixed plate 80a of the shutter 68a via the connecting plate 78a. The drive unit 72b is configured in the same manner as the drive unit 72a described above, and the same reference numerals are assigned to the same reference numerals and the detailed description thereof is omitted.

  The conveyor 54 has a base surface 82 whose transfer direction is set in the arrow F direction. The distance t (see FIG. 4) between the upper surface of the base surface 82 and the lower surface of the mold member 56 is set to the same dimension as the thickness t (see FIG. 7) of the hot melt adhesive 12. Instead of the conveyor 54, an immovable fixed base can be used.

  Therefore, the cylinders 74a and 74b constituting the drive units 72a and 72b are urged, and the rods 76a and 76b protrude outward (in opposite directions). Therefore, as shown in FIG. 8, the shutters 68a and 68b move in directions away from each other under the guide action of the guide rails 70a and 70b. As the shutters 68a and 68b move, the frame-shaped slit 60s of the cavity 60 in the mold member 56 is opened to the outside.

  Therefore, the liquid hot melt adhesive material 62 filled in the cavity 60 is led out on the base surface 82 of the conveyor 54 from the frame-shaped slit 60s. As a result, the frame-shaped member 84 is formed on the base surface 82 by the liquid hot-melt adhesive material 62.

  Next, the cylinders 74a and 74b constituting the drive units 72a and 72b are biased, and the rods 76a and 76b are returned inwardly (in a direction close to each other). For this reason, as shown in FIG. 9, the lower end portion (frame-shaped slit 60 s) of the cavity 60 is closed, and the frame-shaped member 84 is separated from the mold member 56.

  Then, as shown in FIG. 10, it is preferable to move the conveyor 54 downward or raise the mold member 56 slightly to provide a gap between the upper surface of the frame-shaped member 84 and the shutters 68a and 68b. Furthermore, the conveyor 54 is energized, and the base surface 82 is transferred in the direction of arrow F with the molded frame-shaped member 84 placed thereon. The frame-shaped member 84 is conveyed to a drying station (not shown), and the frame-shaped member 84 is subjected to a drying process. As for the dried frame-shaped member 84, an inner peripheral part and an outer peripheral part are trimmed as needed, and the hot-melt-adhesive 12 is manufactured.

  Next, as shown in FIG. 11, in the electrolyte membrane / electrode structure 14a, the frame-shaped hot melt adhesive 12 is formed on the outer peripheral edge portion 19e of the solid polymer electrolyte membrane 19 exposed from the outer periphery of the anode electrode 20 to the outside. Be placed. The resin frame member 24 has an inner peripheral end 24a disposed on the anode electrode 20 side. In this state, the hot melt adhesive 12 is heated and melted (hot melt), and a load (press or the like) is applied to bond the inner peripheral end 24 a and the solid polymer electrolyte membrane 19. Therefore, the electrolyte membrane / electrode structure 14 with a resin frame is manufactured.

  As shown in FIG. 2, the electrolyte membrane / electrode structure 14 with a resin frame is sandwiched between an anode-side separator 18 and a cathode-side separator 16. The anode side separator 18 abuts on the inner peripheral end 24 a of the resin frame member 24, and applies a load to the electrolyte membrane / electrode structure 14 with a resin frame together with the cathode side separator 16. Furthermore, a predetermined number of fuel cells 10 are stacked to form a fuel cell stack, and a tightening load is applied between end plates (not shown).

  The operation of the fuel cell 10 configured as described 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. Further, 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 from the oxidant gas inlet communication hole 30a into the oxidant gas flow path 36 of the cathode-side separator 16 and moves in the arrow A direction to the cathode electrode 22 of the electrolyte membrane / electrode structure 14a. Supplied. On the other hand, the fuel gas is introduced from the fuel gas inlet communication hole 34 a through the supply hole 46 into the fuel gas flow path 38 of the anode side separator 18. The fuel gas moves in the direction of arrow A along the fuel gas flow path 38 and is supplied to the anode electrode 20 of the electrolyte membrane / electrode structure 14a.

  Therefore, in the electrolyte membrane / electrode structure 14a, the oxidant gas supplied to the cathode electrode 22 and the fuel gas supplied to the anode electrode 20 are consumed by the electrochemical reaction in the electrode catalyst layers 22a and 20a. Power generation is performed.

  Next, the oxidant gas consumed by being supplied to the cathode electrode 22 is discharged in the direction of arrow B along the oxidant gas outlet communication hole 30b. Similarly, the fuel gas consumed by being supplied to the anode electrode 20 passes through the discharge hole portion 48 and is discharged in the direction of arrow B 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 path 40 between the anode side separator 18 and the cathode side separator 16 adjacent to each other, and then flows in the direction of the arrow A. The cooling medium is discharged from the cooling medium outlet communication hole 32b after the electrolyte membrane / electrode structure 14a is cooled.

  In this case, in this embodiment, as shown in FIGS. 4, 8, and 9, by opening the shutters 68 a and 68 b constituting the mold apparatus 52, the liquid hot melt is released from the frame-shaped slit 60 s that is continuous with the cavity 60. Adhesive material 62 is extruded. Accordingly, a frame-shaped member 84 made of a liquid hot melt adhesive material 62 is integrally formed on the base surface 82.

  And after drying the frame-shaped member 84, the hot-melt-adhesive 12 which has a frame shape is obtained only by trimming an inner peripheral part and an outer peripheral part. Thereby, the hot-melt-adhesive 12 discarded can be reduced as much as possible, and the effect that it becomes possible to manufacture the said hot-melt-adhesive 12 economically and efficiently is acquired.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 12 ... Hot melt adhesive 14 ... Electrolyte membrane and electrode structure 14a with resin frame 16 ... Electrolyte membrane / electrode structure 16 ... Cathode side separator 18 ... Anode side separator 19 ... Solid polymer electrolyte membrane 20 ... Anode electrode 20a, 22a ... Electrode catalyst layers 20b, 22b ... Gas diffusion layer 22 ... Cathode electrode 24 ... Resin frame member 24a ... Inner peripheral edge 30a ... Oxidant gas inlet communication hole 30b ... Oxidant gas outlet communication hole 32a ... Cooling medium inlet Communication hole 32b ... Cooling medium outlet communication hole 34a ... Fuel gas inlet communication hole 34b ... Fuel gas outlet communication hole 36 ... Oxidant gas flow path 38 ... Fuel gas flow path 40 ... Cooling medium flow path 42, 44 ... Seal member 50 ... Manufacturing system 52 ... Mold device 54 ... Conveyor 56 ... Mold member 60 ... Cavity 60s ... Frame-shaped slit 62 ... Hot melt adhesive material 64 ... core member 68a, 68b ... shutter 70a, 70b ... guide rails 72a, 72b ... drive unit 74a, 74b ... cylinder 82 ... base surface 84 ... frame-shaped member

Claims (2)

A method for producing a hot melt adhesive having a frame shape for joining a resin frame member to an outer periphery of an electrolyte membrane / electrode structure provided with electrodes on both sides of the electrolyte membrane,
Preparing a mold apparatus having a frame-shaped slit that can be opened and closed by a shutter, and forming a frame-shaped member by opening the shutter and extruding a liquid hot-melt adhesive material from the frame-shaped slit;
Drying the molded frame-shaped member;
A method for producing a hot melt adhesive, comprising:   2. The method for manufacturing a hot melt adhesive according to claim 1, further comprising a step of trimming an inner periphery and an outer periphery of the dried frame-shaped member.

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