Fuel cell manufacturing device

Abstract

To provide a fuel cell manufacturing device that can reduce the amount of deformation of a resin frame member, when integrating a membrane electrode joint body, the resin frame member, and a diffusion layer, with upper and lower molds.SOLUTION: A fuel cell manufacturing device has an upper mold 64 and a lower mold 62 provided deformable relative to each other, and at least one of the upper mold and the lower mold is formed of a temperature-adjustable heating mold. The fuel cell manufacturing device has a holding mechanism 70 that, when integrally applying pressure to and crimping a membrane electrode joint body 12 to which a resin frame member 14 is joined and a diffusion layer, with the upper mold 64 and the lower mold 62, holds an outer peripheral part 72 of the resin frame member 14 that is not covered by the diffusion layer.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a fuel cell manufacturing apparatus. [Background technology]

[0002] For example, Patent Document 1 discloses a method for manufacturing a membrane electrode assembly and a fuel cell. According to Patent Document 1, defects in an assembly formed by joining an electrolyte membrane on a first substrate and an electrode on a second substrate are detected.

[0003] Furthermore, Patent Document 1 discloses a manufacturing method in which detected defective products are given marks indicating the defect at different positions so that the marks can be detected in a bonded state, and a diffusion layer is bonded to a bonded body without any marks. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6024629 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the electrolyte membrane thermally shrinks during the bonding of the diffusion layers by thermocompression, the resin frame member bonded to the membrane electrode assembly is likely to shift position due to the thermal shrinkage of the electrolyte membrane, resulting in wrinkles and deformation. If wrinkles or deformation occur in the resin frame member, gas leakage or a reduction in the power generation area due to poor sealing may occur, which may affect the power generation performance of the fuel cell.

[0006] Furthermore, after the diffusion layer is thermocompression bonded, the bonding state (boundary) between the electrolyte membrane and the resin frame member cannot be visually observed, and even if deformation occurs due to thermal contraction, the only way to inspect (evaluate the boundary) is by examining the shade of an image using an X-ray or the like, resulting in problems of low inspection accuracy and efficiency.

[0007] The present invention has been made in view of the above points, and aims to provide a fuel cell manufacturing apparatus that can suppress the amount of deformation of a resin frame member when a membrane electrode assembly, a resin frame member, and a diffusion layer are integrated using upper and lower molds. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the present invention provides a fuel cell manufacturing apparatus including: a membrane electrode assembly consisting of an electrolyte membrane and a pair of electrode catalyst layers provided on both sides of the electrolyte membrane; a resin frame member bonded to the outer periphery of the membrane electrode assembly to hold the membrane electrode assembly; and a diffusion layer covering both sides of the membrane electrode assembly, at least an outer edge of which overlaps with the resin frame member, the apparatus comprising: an upper mold and a lower mold that are provided so as to be displaceable relative to each other, at least one of the upper mold and the lower mold being a heating mold whose temperature can be adjusted; and a holding mechanism that holds the outer periphery of the resin frame member that is not covered by the diffusion layer when the membrane electrode assembly to which the resin frame member is bonded and the diffusion layer are pressurized and bonded together by the upper mold and the lower mold. [Effects of the Invention]

[0009] The present invention provides a fuel cell manufacturing device that can suppress the amount of deformation of the resin frame member when the membrane electrode assembly, the resin frame member, and the diffusion layer are integrated using upper and lower molds. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 2 is an exploded perspective view of a membrane electrode assembly and a resin frame member. [Figure 2] FIG. 2 is a longitudinal cross-sectional view of a resin frame-equipped membrane electrode assembly taken along the horizontal direction. [Figure 3] 10 is an explanatory view showing a state in which the resin frame member is deformed due to thermal contraction of the electrolyte membrane when the diffusion layer is bonded. FIG. [Figure 4] 1 is a schematic cross-sectional view of a mold device and a holding mechanism to which a fuel cell manufacturing apparatus according to an embodiment of the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0011] Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0012] First, the structure of a power-generating cell manufactured by a fuel cell manufacturing apparatus according to an embodiment of the present invention will be described. This power-generating cell (fuel cell) is configured with a resin-framed membrane electrode assembly 10 (see FIG. 2) and a pair of separators (not shown) arranged on both sides of the resin-framed membrane electrode assembly 10. The power-generating cell is a horizontally elongated rectangular polymer electrolyte fuel cell. A plurality of power-generating cells are stacked, for example, horizontally or vertically, to form a fuel cell stack. The fuel cell stack is installed, for example, in a fuel cell electric vehicle as an on-board fuel cell stack.

[0013] The resin-framed membrane electrode assembly 10 includes a membrane electrode assembly 12 and a resin frame member 14 joined to the outer periphery of the membrane electrode assembly 12 and extending around the outer periphery (see FIG. 1). Note that the diffusion layer joined to the membrane electrode assembly 12 is not shown in FIG.

[0014] As shown in FIG. 2, the membrane electrode assembly 12 includes an electrolyte membrane 16 having a rectangular shape in a plan view, an anode electrode (electrode catalyst layer) 18 provided on either the front or back surface of the electrolyte membrane 16, and a cathode electrode (electrode catalyst layer) 20 provided on the other of the front or back surface of the electrolyte membrane 16 (see FIG. 1).

[0015] The electrolyte membrane 16 is made of, for example, a solid polymer electrolyte membrane (cation exchange membrane). The solid polymer electrolyte membrane is, for example, a thin film of perfluorosulfonic acid containing water. The front and back surfaces of the electrolyte membrane 16 are sandwiched between an anode electrode 18 and a cathode electrode 20.

[0016] In this embodiment, the cathode electrode 20 has larger planar dimensions (external dimensions) than the anode electrode 18, and the cathode electrode 20 and the electrolyte membrane 16 have the same or approximately the same planar dimensions (external dimensions). In other words, as shown in Fig. 2, the outer peripheral edge 22 of the cathode electrode 20 and the outer peripheral edge 24 of the electrolyte membrane 16 are located at the same position in the thickness direction, and the outer peripheral edge 26 of the anode electrode 18 is located more inward in the thickness direction than the outer peripheral edge 22 of the cathode electrode 20 and the outer peripheral edge 24 of the electrolyte membrane 16.

[0017] The membrane electrode assembly 12 has a pair of diffusion layers covering both surfaces of the membrane electrode assembly 12, with at least the outer edge overlapping the resin frame member 14 in the thickness direction. The pair of diffusion layers comprises an anode electrode-side gas diffusion layer 28 laminated on one surface of the anode electrode 18 and a cathode electrode-side gas diffusion layer 30 laminated on one surface of the cathode electrode 20. An outer peripheral edge 32 of the anode electrode-side gas diffusion layer 28 and an outer peripheral edge 34 of the cathode electrode-side gas diffusion layer 30 are located at the same positions in the thickness direction as the outer peripheral edge 22 of the cathode electrode 20 and the outer peripheral edge 24 of the electrolyte membrane 16, respectively. The anode electrode-side gas diffusion layer 28 and the cathode electrode-side gas diffusion layer 30 are each formed from carbon paper, carbon cloth, or the like.

[0018] The resin frame member 14 is made up of two frame-shaped sheets having approximately the same thickness but different planar dimensions (external dimensions). The resin frame member 14 has an opening (window frame) at its inner peripheral edge that is approximately rectangular in plan view.

[0019] Specifically, the resin frame member 14 has a first frame-shaped sheet body 40, the inner periphery 38 of which is bonded to one surface of the membrane electrode assembly 12 via an adhesive layer 36 described below, and a second frame-shaped sheet body 42 bonded to the first frame-shaped sheet body 40 via the adhesive layer 36. The first frame-shaped sheet body 40 and the second frame-shaped sheet body 42 are bonded to each other in the thickness direction by the adhesive layer 36 made of an adhesive. An inner periphery 44 of the second frame-shaped sheet body 42 is bonded to the other surface of the membrane electrode assembly 12 via the adhesive layer 36.

[0020] The inner peripheral edge 46 of the first frame-shaped sheet 40, which is joined to one surface of the membrane electrode assembly 12, protrudes inward more than the inner peripheral edge 48 of the second frame-shaped sheet 42, which is joined to the other surface of the membrane electrode assembly 12. It is necessary to ensure a dimensional guarantee for the dimension from the outer peripheral edge 32 of the anode electrode side gas diffusion layer 28 to the inner peripheral edge 46 of the first frame-shaped sheet 40, which is joined to one surface of the membrane electrode assembly 12. It is also necessary to ensure a dimensional guarantee for the dimension from the outer peripheral edge 34 of the cathode electrode side gas diffusion layer 30 to the inner peripheral edge 48 of the second frame-shaped sheet 42, which is joined to the other surface of the membrane electrode assembly 12.

[0021] The resin-framed membrane electrode assembly 10 further includes an overlap area 50, a tent area 52, and an active area 54. The overlap area 50 is formed by an overlapping region of the membrane electrode assembly 12, the outer periphery of the diffusion layers (28, 30), and the inner periphery of the resin frame member 14. The tent area 52 is formed by an approximately triangular space 56 formed between the inner periphery 46 of the first frame-shaped sheet body 40, the electrolyte membrane 16, and the anode electrode-side gas diffusion layer 28. The active area 54 is formed by an overlapping region of the membrane electrode assembly 12 and the diffusion layer.

[0022] The power generating cell manufactured by the fuel cell manufacturing apparatus according to this embodiment is basically configured as described above, and its effects will now be described.

[0023] The manufacturing process of the resin frame-equipped membrane electrode assembly 10 will be described in detail below.

[0024] First, a resin frame member joining step is performed to join the resin frame member 14 to the membrane electrode assembly 12. An adhesive is applied to the outer periphery of the membrane electrode assembly 12 to join the membrane electrode assembly 12 to the first frame-shaped sheet body 40 and the second frame-shaped sheet body 42.

[0025] Next, after the resin frame member joining step, a diffusion layer joining step is performed to join the diffusion layers. The anode electrode side gas diffusion layer 28 is laminated on one surface of the anode electrode 18 and on a portion of the inner periphery of the first frame-shaped sheet body 40. At approximately the same time, the cathode electrode side gas diffusion layer 30 is laminated on one surface of the cathode electrode 20 and on a portion of the inner periphery of the second frame-shaped sheet body 42. After laminating the diffusion layers, the diffusion layers in the active area 58 and the membrane electrode assembly 12 are heated and pressed together using a mold device 60.

[0026] 4, mold device 60 includes a lower mold 62 which is a room temperature mold, an upper mold 64 which is a heated mold whose heating temperature can be adjusted and which is provided so as to be displaceable in the vertical direction relative to lower mold 62 via a lifting mechanism (not shown), and a buffer material 66 which is placed on the upper surface of lower mold 62 and on which the material to be pressed is placed. A holding mechanism 70 which constitutes part of the manufacturing apparatus according to an embodiment of the present invention is disposed near upper mold 62 and lower mold 64.

[0027] This holding mechanism 70 holds the outer peripheral portion 72 of the resin frame member 14, which is not covered by the diffusion layers, in the vertical direction when the membrane electrode assembly 12 to which the resin frame member 14 is joined and the diffusion layers covering the upper and lower surfaces of the membrane electrode assembly 12, respectively, are pressurized and bonded together by the upper mold 64 and the lower mold 62.

[0028] The holding mechanism 70 has a gripping portion 74 that presses vertically to grip the outer peripheral portion 72 of the resin frame member 14 that is not covered with the diffusion layer. The gripping portion 74 has a metal base jig 76 that is placed on the underside of the outer peripheral portion 72 of the resin frame member 14, and a magnet 78 that is placed on the upper surface of the outer peripheral portion 72 of the resin frame member 14. The magnet 78 and the base jig 76 each have a rectangular cross section and are formed as a square-shaped frame body in plan view with an opening that surrounds the outer peripheral edge of the diffusion layer. Note that, although the cross-sectional width of the base jig 76 is larger than that of the magnet 78 in FIG. 4, they may have approximately the same width.

[0029] Furthermore, the magnet 78 and the base jig 76 are configured separately from the upper die 64 and the lower die 62, and are arranged at a predetermined distance from the side surfaces of the upper die 64 and the lower die 62. This is to prevent contact between the upper die 64 and the lower die 62 when the upper die 64 is displaced downward and comes into contact with the lower die 62 to pressurize and bond the material to be crimped.

[0030] In the holding mechanism 70, the outer peripheral portion 72 of the resin frame member 14 that is not covered with the diffusion layer is gripped in the vertical direction by the magnetic force (white arrow C) acting on the base jig 76 of the magnet 78. In addition, the base jig 76 is preferably elastically supported by a spring (not shown).

[0031] Furthermore, the magnet 78 and the base jig 76 may be set between the upper mold 64 and the lower mold 62 in a state in which they have previously gripped the outer periphery 72 of the resin frame member 14 that is not covered with the diffusion layer. Alternatively, the membrane electrode assembly 12 to which the resin frame member 14 is joined and the diffusion layer may be placed on the upper surface of the lower mold 62, and then the magnet 78 and the base jig 76 may be positioned to grip the outer periphery 72 of the resin frame member 14 that is not covered with the diffusion layer.

[0032] As shown in FIG. 3, when the diffusion layers are pressure-bonded by thermocompression bonding, thermal shrinkage (shrinkage due to heat) of the electrolyte membrane 16 occurs (see open arrow A). At the same time, or approximately at the same time, the resin frame member 14 bonded to the membrane electrode assembly 12 may shift position due to the thermal shrinkage of the electrolyte membrane 16, resulting in wrinkles and deformation (see open arrow B). If wrinkles or deformation occur in the resin frame member 14, this may result in gas leakage due to poor sealing or a reduction in the power generation area, which could affect the power generation performance of the fuel cell. In FIG. 3, the amount of thermal shrinkage of the electrolyte membrane 16 indicated by open arrow A and the amount of deformation of the resin frame member 14 indicated by open arrow B are the same or approximately the same.

[0033] In contrast, in this embodiment, a holding mechanism 70 is provided that holds an outer periphery 72 of the resin frame member 14 that is not covered by the diffusion layer when the membrane electrode assembly 12 to which the resin frame member 14 is bonded and the diffusion layers that cover the upper and lower surfaces of the membrane electrode assembly 12, respectively, are pressurized and bonded together by the upper mold 64 and the lower mold 62. As a result, in this embodiment, even if the membrane electrode assembly 12 thermally shrinks in the direction of the outline arrow A, the outer periphery 72 of the resin frame member 14 that is not covered by the diffusion layer is held in a predetermined position by the magnetic force of the magnet 78 with respect to the base jig 76, preventing displacement and deformation.

[0034] Therefore, in this embodiment, it is possible to reliably ensure the dimensions from the outer peripheral edge 32 of the anode electrode side gas diffusion layer 28 to the inner peripheral edge 46 of the first frame-shaped sheet body 40, and the dimensions from the outer peripheral edge 34 of the cathode electrode side gas diffusion layer 30 to the inner peripheral edge 48 of the second frame-shaped sheet body 42. As a result, in this embodiment, when the membrane electrode assembly 12, the resin frame member 14, and the diffusion layer are press-bonded together using the upper mold 64 and the lower mold 62, the amount of deformation of the resin frame member 14 due to thermal contraction of the membrane electrode assembly 12 can be suppressed.

[0035] Furthermore, in this embodiment, the introduction of an X-ray transmission device is not required, and the dimensional measurement and dimensional assurance of the opening of the resin frame member 14 can be easily performed.

[0036] Furthermore, in this embodiment, the holding mechanism 70 has a holding portion 74 that presses and holds the outer periphery 72 of the resin frame member 14 in the vertical direction. As a result, in this embodiment, the outer periphery 72 of the resin frame member 14, which is not covered with the diffusion layer, can be securely held without being damaged.

[0037] Furthermore, in this embodiment, the magnet 78 and the base jig 76 are configured as a frame having an opening surrounding the outer periphery of the diffusion layer in plan view, which allows the outer periphery 72 of the resin frame member 14, which is not covered by the diffusion layer, to be uniformly and stably held.

[0038] In this embodiment, the magnet 78 and the base jig 76 are given as examples of the holding mechanism 70, but any mechanism can be used as long as it presses and grips the outer periphery 72 of the resin frame member 14 in the vertical direction. For example, the outer periphery 72 of the resin frame member 14 may be gripped using a robot arm (not shown). [Explanation of symbols]

[0039] 10 Resin-framed electrolyte membrane-electrode assembly 12 Membrane electrode assembly 14 Resin frame member 16 Electrolyte membrane 18 Anode electrode (electrode catalyst layer) 20 Cathode electrode (electrode catalyst layer) 28 Anode electrode side diffusion layer (diffusion layer) 30 Cathode electrode side diffusion layer (diffusion layer) 60 Mold equipment 62 Upper mold 64 Lower mold 70 Retention mechanism 72 Outer periphery 74 Gripping part 76 Base jig 78 Magnet

Claims

1. a membrane electrode assembly comprising an electrolyte membrane and a pair of electrode catalyst layers provided on both sides of the electrolyte membrane; a resin frame member joined to the outer periphery of the membrane electrode assembly to hold the membrane electrode assembly; a diffusion layer covering both surfaces of the membrane electrode assembly and having at least an outer edge portion overlapping the resin frame member, The mold has an upper mold and a lower mold that are provided so as to be displaceable relative to each other, and at least one of the upper mold and the lower mold is a heating mold whose temperature can be adjusted; a holding mechanism that holds the outer periphery of the resin frame member that is not covered by the diffusion layer when the membrane electrode assembly to which the resin frame member is joined and the diffusion layer are pressurized and bonded together by the upper mold and the lower mold.

2. 2. The fuel cell manufacturing apparatus according to claim 1, The fuel cell manufacturing device is characterized in that the holding mechanism has a gripping portion that presses the outer periphery of the resin frame member in the vertical direction to grip it.

3. 3. The fuel cell manufacturing apparatus according to claim 2, A fuel cell manufacturing apparatus characterized in that the gripping portion has a metal base jig placed on the underside of the outer periphery of the resin frame member, and a magnet placed on the upper surface of the outer periphery of the resin frame member.

4. 4. The fuel cell manufacturing apparatus according to claim 3, The fuel cell manufacturing device is characterized in that the magnet and the base jig are configured as a frame having an opening surrounding the outer periphery of the diffusion layer in plan view.

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