JP5146630B2 - Gasket integrated with reinforcing frame and manufacturing method thereof - Google Patents

Description

  The present invention relates to a gasket that is used in, for example, a fuel battery cell and is integrally provided on a reinforcing frame, and a method for manufacturing the gasket.

  The fuel cell has a stack structure in which a large number of fuel cells each having both sides in the thickness direction of a membrane electrode assembly (MEA) provided with a pair of catalyst electrode layers on both sides of a polymer electrolyte membrane are sandwiched by separators. An oxidizing gas (air) is supplied from one oxidizing gas flow path formed on one surface of each separator to one catalyst electrode layer, and a fuel gas (hydrogen) is formed on the other surface of each separator. Electric power is generated by an electrochemical reaction that is the reverse reaction of water electrolysis, that is, a reaction that generates water from hydrogen and oxygen, which is supplied from the flow path to the other catalyst electrode layer.

In this type of fuel cell, each fuel cell is equipped with a gasket for sealing fuel gas, oxidizing gas, water discharged from the cathode surface, and excess air. This type of gasket is made of a single rubber-like elastic material, and its handling property deteriorates as the cross-sectional area becomes smaller. Therefore, a gasket integrated with a reinforcing frame is used. FIG. 6 is a partial cross-sectional view showing an example of a gasket integrated with a reinforcing frame according to a conventional technique. As shown in FIG. 6, this type of gasket 100 is provided with a gasket body 101 made of a rubber-like elastic material on both surfaces of the reinforcing frame 102 in terms of its function.
(For example, see the following patent document)
JP 2001-332276 A

  However, when the reinforcing frame 102 has a low bending rigidity, such as a synthetic resin film or a very thin metal foil, when the gasket main body 101 is molded on both surfaces at the same time, the injection pressure of the rubber material and the flow of the rubber material 6, the reinforcing frame 102 is bent as shown by the broken line in FIG. 6, and the position between the gasket bodies 101, 101 is changed, so that stable sealing performance cannot be obtained, or the reinforcing frame 102 may be damaged. There is also. For this reason, when the flexural rigidity of the reinforcing frame 102 is low, it is necessary to form the gasket body 101 in two steps on each side, making it difficult to produce at low cost.

  In addition, if the reinforcement frame 102 has a high bending rigidity, the gasket body 101 can be formed on both sides at once. However, in order to increase the bending rigidity of the reinforcement frame 102, its thickness is increased. However, since this increases the size of the fuel cell, this reinforcing frame 102 is used in a strong acid atmosphere inside the fuel cell. It was also difficult to increase the rigidity.

  The present invention has been made in view of the above points, and the technical problem is that the gasket integrated with the reinforcing frame body can stabilize the quality and can be produced at low cost. There is to do.

As means for effectively solving the technical problem described above, the gasket integrated with the reinforcing frame according to the invention of claim 1 is arranged along the film-like or plate-like reinforcing frame and the periphery thereof. A gasket body made of a rubber-like elastic material, and the gasket body has one surface substantially flush with one surface of the reinforcement frame body and covers the other surface of the peripheral edge. And a flat base integrally joined to each other and seal lips formed on both sides in the thickness direction of the reinforcing base so as to be located outside the peripheral edge of the reinforcing frame.

  A gasket manufacturing method according to the invention of claim 2 is a method for manufacturing a gasket integral with the reinforcing frame described in claim 1, wherein the reinforcing frame is set in a mold, The reinforcing frame has a peripheral edge positioned in a molding cavity defined between the divided surfaces of the mold and is supported on one of the divided surfaces. The peripheral edge of the reinforcing frame body is filled with an unvulcanized rubber material and vulcanized from an injection port provided at a position facing the surface facing the inside of the molding cavity at the peripheral edge of the reinforcing frame body. The gasket body is integrally formed.

  According to the gasket integral with the reinforcing frame according to the first aspect of the present invention, since the seal lip in the gasket body is formed outside the peripheral edge of the reinforcing frame, the sealing performance by the seal lip is improved. Stable sealing performance can be achieved without being affected by the body. The reinforcing frame is not exposed to the fluid to be sealed, and thus the degree of freedom in selecting the material of the reinforcing frame can be expanded.

  According to the gasket manufacturing method of the second aspect of the present invention, the injection pressure of the unvulcanized rubber material filled into the molding cavity from the injection port acts on the periphery of the reinforcing frame. Is supported by one of the dividing surfaces of the mold, so that even if the reinforcing frame has a relatively low rigidity, it does not bend or break. For this reason, the gasket integrated with the reinforcing frame according to the first aspect of the invention can be easily molded and provided at low cost, and the quality can be stabilized.

  Hereinafter, a gasket integrated with a reinforcing frame according to the present invention and a manufacturing method thereof will be described with reference to the drawings. FIG. 1 is a plan view showing a preferred embodiment in which a gasket integrated with a reinforcing frame according to the present invention is applied to a fuel cell stack seal, FIG. 2 is a cross-sectional view taken along the line II-II in FIG. It is sectional drawing which expands and shows the principal part of FIG.

  A gasket 1 as a fuel cell stack seal shown in FIGS. 1 and 2 has a window portion 1a corresponding to a power generation region of a fuel cell, which will be described later, and a plurality of passage holes 1b corresponding to each manifold of the fuel cell. The reinforcing frame 11 is provided with a gasket body 12 integrated with the peripheral edge of the window portion 1a and the peripheral edge of the passage hole 1b.

  The reinforcing frame 11 is made of a synthetic resin film such as polyimide (PI), polyethylene naphthalate (PEN), or polyethylene terephthalate (PET) excellent in electrical insulation, and as shown in FIG. The outer peripheral edge is formed in the same shape and size as the outer peripheral edge of the separator 3.

  The gasket body 12 is made of a rubber-like elastic material such as ethylene propylene rubber (EPDM), VMQ (silicon rubber), or fluorine rubber (FKM). As shown in FIGS. The window portion 1a and the passage hole 1b are integrally joined to the periphery of the reinforcing frame 11.

  Specifically, as shown in FIG. 3, the gasket main body 12 is formed integrally with the reinforcing frame 11 so that one surface 121 a is substantially flush with the one surface 11 a of the reinforcing frame 11 ( The flat base 121 is bonded, and seal lips 122 are formed on both sides in the thickness direction of the base 121 and are formed outside the peripheral edge 111 of the reinforcing frame 11. The seal lip 122 is provided so as to surround the window portion 1a and the passage hole 1b.

  FIG. 4 is a partial cross-sectional view showing the relationship between the gasket 1 having the above-described configuration and the fuel battery cell. As shown in FIG. 4, each fuel cell has a MEA (Membrane Electrode Assembly) in which a pair of electrode layers 22 including a catalyst layer and a gas diffusion layer are provided on both sides of a polymer electrolyte membrane 21. ) 2 and a separator 3 that supplies a fuel gas or an oxidizing gas to the electrode layer 22 and has a function as a current collector, and the gasket 1 is located on the outer peripheral side of the electrode layer 22 of the MEA 2. 3 is interposed between the outer peripheral portions.

  The separator 3 is made of carbon that is electrically conductive and impermeable to gas, and a plurality of groove-like gas flow paths (not shown) are formed on both surfaces of the separator 3 so as to face the electrode layer 22. In the outer periphery, a plurality of passage holes 3a are provided for supplying or discharging fuel gas or oxidizing gas to the gas flow path or supplying or discharging cooling water.

  In the fuel cell having the above configuration, in each fuel cell, a gas flow path formed between the electrode layer 22 on one side of the MEA 2 and the separator 3 is provided with a manifold composed of mutually overlapped passage holes 3a and 1b. The fuel gas (hydrogen) is supplied through the gas flow path formed between the electrode layer 22 on the other side and the separator 3, and the oxidizing gas passes through a manifold formed of other passage holes 3 a and 1 b that are superposed on each other. (Oxygen) is supplied. On the side to which the fuel gas is supplied (anode), a reaction for decomposing hydrogen molecules into hydrogen ions and electrons is performed, and on the side to which the oxidizing gas is supplied (cathode), oxygen, hydrogen ions, and electrons are used. A reaction to generate water is performed, thereby generating an electromotive force.

Of the seal lips 122 ₁ and 122 ₂ provided to surround the window portion 1 a in the gasket main body 12 of the gasket 1, the outer peripheral seal lip 122 ₁ is appropriately crushed by the separators 3 and 3 on both sides. The seal lip 1222 on the inner peripheral side is connected to the outer peripheral part of the MEA ₂ (polymer electrolyte membrane 21) on the other side. It has a function of being sandwiched between the separator 3. Furthermore, manifold (passage hole 3a, 1b) seal lip 122 ₃ provided so as to surround the can close with a suitable collapse margin in the separator 3, the fuel gas flowing through the said manifold, excellent for the oxidizing gas or the coolant Has a good sealing property.

  According to the gasket 1 described above, the seal lip 122 of the gasket body 12 is formed outside the peripheral edge 111 of the reinforcing frame 11, so that the double-sided seal lip 122 is similar to the rubber-only gasket. It is uniformly compressed without being affected by the reinforcing frame 11, and stable sealing performance can be achieved. In addition, since the reinforcing frame 11 is not exposed to the fuel gas, oxidizing gas, or cooling water to be sealed, the degree of freedom in selecting the material of the reinforcing frame 11 can be widened.

  FIG. 5 is a cross-sectional view of an essential part showing a method for manufacturing the gasket 1 as a preferred embodiment of the method for manufacturing a gasket according to the present invention.

  In FIG. 5, reference numeral 4 is a mold including an upper mold 41 and a lower mold 42. A molding cavity 43 having a shape corresponding to the gasket body 12 in the gasket 1 is formed between the divided surfaces 41a and 42a of the upper mold 41 and the lower mold 42 that are in contact with each other. That is, the molding cavity 43 includes a flat base molding portion 431 having a shape corresponding to the base 121 of the gasket body 12 and a seal lip molding portion 432 having a shape corresponding to the seal lip 122 of the gasket body 12.

  In the upper mold 41, an injection gate (injection port) 411 for filling the molding cavity 43 with the unvulcanized rubber material is opened toward the base molding portion 431 of the molding cavity 43. In addition, a pressing protrusion 412 that clamps the reinforcing frame 11 with the lower die 42 by clamping is formed on the outer peripheral side of the molding cavity 43 on the surface of the upper die 41 facing the lower die 42. .

  When the gasket body 12 is integrally formed on the reinforcing frame 11, first, the reinforcing frame 11 formed in a required planar shape by punching a synthetic resin film or the like is set in the mold 4 and clamped. . Specifically, the reinforcing frame 11 has the peripheral edge 111 corresponding to the window portion 1 a and the passage hole 1 b shown in FIG. 1 positioned at the base molding portion 431 in the molding cavity 43 and the dividing surface 42 a of the lower die 42. It is supported on the upper die 41 and is held between the split surface 42 a by the pressing protrusion 412 of the upper die 41.

  Next, an unvulcanized rubber material is filled from the injection gate 411 opened in the upper mold 41 into the molding cavity 43 sealed by clamping the upper mold 41 and the lower mold 42 and vulcanized. The injection gate 411 opens toward the base molding portion 431 where the peripheral edge 111 of the reinforcement frame body 11 exists, that is, the injection gate 411 of the reinforcement frame body 11 supported on the dividing surface 42a of the lower mold 42 in the base molding portion 431. Since the opening is opened at a position facing the supported surface (one surface 11a) of the peripheral edge 111 and the other surface 11b on the opposite side, it has not yet flowed into the molding cavity 43 (base molding portion 431) from the injection gate 411. The injection pressure and flow pressure of the vulcanized rubber material act so as to press the peripheral edge 111 of the reinforcing frame 11 against the dividing surface 42 a of the lower mold 42.

  For this reason, the rubber material filled in the molding cavity 43 is vulcanized and cured in a state where the one surface 11a of the reinforcing frame 11 is in close contact with the dividing surface 42a of the lower mold 42, as shown in FIG. As shown, a gasket 1 in which a gasket body 12 is integrated with a reinforcing frame 11 is obtained, and the gasket body 12 has one surface 121a of the base 121 substantially the same as one surface 11a of the reinforcing frame 11. It is integrally bonded to the peripheral edge 111 of the reinforcing frame 11 in the same plane.

  Further, as shown in FIG. 1, a plurality of gasket bodies 12 can be integrated into a single reinforcing frame 11 in accordance with the arrangement of the window portion 1a and the passage hole 1b, and can be manufactured at low cost. .

  A test was conducted in which the gasket body 12 was integrally molded with liquid silicon rubber on the reinforcing frame 11 made of a PI film having a wall thickness of about 125 μm. As a result, when the interval between the injection gates 411 was about 100 mm, a thin burr with a thickness of several μm occurred on the surface (one surface 11a) opposite to the base 121 at the peripheral edge 111 of the reinforcing frame 11, It was confirmed that the frame 11 was not bent and could be integrally formed stably.

  Moreover, although the reinforcement frame 11 performed shaping | molding also about what consists of a PEN film and PET film, the same result was obtained. Therefore, it was confirmed that good molding is possible regardless of the material of the reinforcing frame 11.

It is a top view which shows preferable embodiment of the gasket integral with the reinforcement frame which concerns on this invention. It is II-II sectional drawing in FIG. It is sectional drawing which expands and shows the principal part of FIG. It is a fragmentary sectional view which shows the relationship between the gasket and fuel cell by embodiment of this invention. It is principal part sectional drawing which shows preferable embodiment which shows the manufacturing method of the gasket which concerns on this invention. It is a fragmentary sectional view which shows an example of the gasket integral with the reinforcement frame body by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gasket 1a Window part 1b Passage hole 11 Reinforcement frame 11a One surface 111 Periphery 12 Gasket body 121 Base 121a One surface 122 Seal lip 4 Mold 41 Upper mold 41a, 42a Dividing surface 411 Injection gate (injection port)
412 Pressing projection 42 Lower mold 43 Molding cavity 431 Base molding part 432 Seal lip molding part

Claims (2)

A film-like or plate-like reinforcing frame (11) and a gasket main body (12) made of a rubber-like elastic material disposed along the periphery (111) thereof, the gasket main body (12) The surface (121a) is integrally joined to the reinforcing frame (11) so that the surface (121a) is substantially flush with the one surface (11a) of the reinforcing frame (11) and covers the other surface of the peripheral edge (111). A flat base (121) and seal lips (122) formed on both sides of the reinforcing frame (11) on the outer sides of the peripheral edge (111) of the reinforcing frame (11). Gasket integrated with the reinforcing frame.   In the manufacture of the gasket (1) integrated with the reinforcing frame described in claim 1, the reinforcing frame (11) is set in the mold (4), and the reinforcing frame (11) has a peripheral edge ( 111) is positioned in the molding cavity (43) defined between the split surfaces (41a, 42a) of the mold (4) and is supported on one of the split surfaces (42a). Thereafter, an injection port opened in the molding cavity (43) at a position facing the surface (11b) facing the molding cavity (43) in the peripheral edge (111) of the reinforcing frame (11). A gasket main body (12) is integrally formed on the peripheral edge (111) of the reinforcing frame (11) by filling and vulcanizing an unvulcanized rubber material from (411). .

Images