Manufacturing Method of Film-Integrated Gasket

Abstract

The present invention provides a method for manufacturing a thin film integrated gasket capable of suppressing molding defects, characterized in that it includes: a first step, in a state where a resin film (120) is arranged between a first lower mold (310) and a first upper mold (320), the first lower mold (310) and the first upper mold (320) are molded together, and a molding material is filled into a first cavity (321) to mold a first gasket (131); and a second step, in a state where a resin film (120) integrally provided with the first gasket (131) is arranged between a second lower mold (330) and a second upper mold (340), the second lower mold (330) having a groove (331) for configuring the first gasket (131) and the second upper mold (340) are molded together, and a molding material is filled into a second cavity (341) to mold a second gasket, wherein the first opening width (W32) is narrower than the second opening width (W34).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a thin film integrated gasket in which gaskets are integrally provided on both surfaces of a film. Background Art

[0002] A solid polymer fuel cell includes an electrolyte membrane. A technique for reinforcing the electrolyte membrane with a resin film is known. In addition, in order to improve the workability during assembly of the fuel cell, a technique for integrally providing gaskets on both sides of the resin film is also known. Figure 4 and Figure 5 , a thin film integrated gasket and a manufacturing method thereof of such a prior art are described. Figure 4 It is a part of the cross-sectional view of the thin film integrated gasket of the prior art. Figure 5 This is a manufacturing process diagram of a thin film integrated gasket according to the prior art, showing a portion of a cross-sectional view of the thin film integrated gasket and a mold.

[0003] A conventional film-integrated gasket 500 includes a resin film 510, and a first gasket 521 and a second gasket 522 provided integrally with the resin film 510 on both sides of the resin film 510. The second gasket 522 has the same size and shape as the first gasket 521 and is provided on the front and back sides of the first gasket 521 along the first gasket 521 with the resin film 510 interposed therebetween.

[0004] Reference Figure 5 , the manufacturing method of the film integrated gasket 500 is described. First, with the resin film 510 disposed between the first lower mold 610 and the upper mold 620, the first lower mold 610 and the upper mold 620 having the cavity 621 for forming the first gasket 521 are molded together (refer to Figure 5 Then, the molding material is filled into the mold cavity 621 to mold the first gasket 521. Thereafter, the mold is opened and the resin film 510 integrally molded with the first gasket 521 is taken out.

[0005] Next, with the resin film 510 integrally provided with the first gasket 521 disposed between the second lower mold 630 and the upper mold 620, the second lower mold 630 having the groove 631 for disposing the first gasket 521 and the upper mold 620 having the cavity 621 for molding the second gasket 522 are clamped (see FIG. Figure 5 (b)). Then, the molding material is filled into the mold cavity 621 to mold the second gasket 522. Thereafter, the mold is opened and the resin film 510 integrally molded with the first gasket 521 and the second gasket 522 is removed.

[0006] As described above, the upper mold 620 having the same mold or the same size and shape as the cavity 621 for molding the first and second gaskets 521 and 522 is used. In contrast, when molding the first gasket 521, the lower mold 610 is used, whose upper surface is formed flat at least at the portion facing the cavity 621 of the upper mold 620. Furthermore, when molding the second gasket 522, the second lower mold 630 is used, which has a groove 631 for accommodating the first gasket 521, so that the first gasket 521 does not interfere.

[0007] To prevent the groove 631 from interfering with the first gasket 521, gaps are formed between the side surfaces and the bottom surface of the groove 631 and the first gasket 521. Therefore, the opening width W63 of the groove 631 on the resin film side, perpendicular to the groove 631's extension direction, is wider than the opening width W62 of the cavity 621 on the resin film side, perpendicular to the cavity 621's extension direction. Therefore, when the mold is closed to mold the second gasket 522, gaps S are formed between the first gasket 521 and the side surfaces of the groove 631. Consequently, these gaps S exist on the front and back sides of both sides of the cavity 621 in the upper mold 620, separated by the resin film 510. Because the resin film 510 is flexible, the pressing force of the upper mold 620 against the resin film 510 is likely to be insufficient in the circled X portion of the figure. This can easily cause burrs, making post-processing difficult and potentially leading to molding defects such as molding material leakage.

[0008] Furthermore, similar problems may occur during the manufacture of any film-integrated gasket not limited to the case of manufacturing a film-integrated gasket for use in a fuel cell, particularly any film-integrated gasket in which gaskets are integrally provided on both surfaces of a flexible film.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2010-67371

[0012] Patent Document 2: Japanese Patent Application Laid-Open No. 2009-99531

[0013] Patent Document 3: Japanese Patent Application Laid-Open No. 2006-344541 Summary of the Invention

[0014] Problems to be solved by the invention

[0015] An object of the present invention is to provide a method for manufacturing a thin-film integrated gasket capable of suppressing molding defects.

[0016] Means used to solve problems

[0017] The present invention adopts the following means to solve the above-mentioned problems.

[0018] That is, the present invention provides a method for manufacturing a thin film integrated gasket, wherein the thin film integrated gasket has a portion in which a first gasket is integrally provided on one surface of a thin film and a second gasket is integrally provided along the first gasket on the other surface of the thin film, i.e., at a position opposite to and behind the first gasket. The manufacturing method is characterized by comprising:

[0019] In a first step, the film is arranged between the first lower mold and the first upper mold, the first lower mold and the first upper mold having a first cavity for forming the first gasket are clamped together, and the first cavity is filled with a molding material to form the first gasket; and

[0020] In the second step, the film integrally provided with the first gasket is arranged between the second lower mold and the second upper mold, and the second lower mold having a groove for arranging the first gasket and the second upper mold having a second cavity for molding the second gasket are clamped together, and the molding material is filled into the second cavity to mold the second gasket.

[0021] The first opening width of the film side in the first cavity in a direction perpendicular to the extension direction of the first cavity is narrower than the second opening width of the film side in the second cavity in a direction perpendicular to the extension direction of the second cavity.

[0022] According to the present invention, the width of the film side of the first gasket molded in the first cavity is narrower than the width of the second opening in the second cavity. This allows the width of the groove in the second lower mold to be narrowed. Consequently, the gaps between the front and back sides of the second cavity formed in the second upper mold through the film can be narrowed or eliminated.

[0023] Preferably, the second opening width is equal to or greater than a third opening width of the groove on the film side in a direction perpendicular to the extending direction of the groove.

[0024] This prevents the formation of gaps on the front and back surfaces of both side portions of the second cavity in the second upper mold via the film.

[0025] The feature is that the center of the third opening width is located directly behind the center of the second opening width with the film interposed therebetween.

[0026] Thus, no gap is formed on the front and back sides of both side portions of the second cavity in the second upper mold via the film.

[0027] Preferably, the film is a resin film for reinforcing an electrolyte membrane provided in a fuel cell.

[0028] In addition, the above-mentioned structures can be combined and adopted as much as possible.

[0029] Effects of the Invention

[0030] As described above, according to the present invention, it is possible to suppress molding defects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a top view of a thin film integrated gasket according to an embodiment of the present invention.

[0032] Figure 2 It is a partial cross-sectional view of a fuel cell including a film-integrated gasket according to an embodiment of the present invention.

[0033] Figure 3 This is a diagram of the manufacturing process of the thin film integrated gasket involved in the embodiment of the present invention.

[0034] Figure 4 It is a part of the cross-sectional view of the thin film integrated gasket of the prior art.

[0035] Figure 5 This is a manufacturing process diagram of a thin film integrated gasket in the prior art. DETAILED DESCRIPTION

[0036] The following describes, in detail and by way of example, embodiments of the present invention with reference to the accompanying drawings. However, unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of the components described in these embodiments are not intended to limit the scope of the present invention. The following embodiments utilize a thin-film integrated gasket for use in a fuel cell as an example.

[0037] (Example)

[0038] Reference Figures 1 to 3 , a method for manufacturing a thin film integrated gasket involved in an embodiment of the present invention is described. Figure 1 It is a top view of a thin film integrated gasket according to an embodiment of the present invention. Figure 2 This is a part of a cross-sectional view of a fuel cell having a thin film integrated gasket according to an embodiment of the present invention. The cross-sectional view of the thin film integrated gasket in the figure is equivalent to Figure 1 AA section view in. Figure 3 This is a manufacturing process diagram of a thin-film integrated gasket according to an embodiment of the present invention, showing a portion of a cross-sectional view of the thin-film integrated gasket and a mold.

[0039] <Fuel Cell>

[0040] Reference Figure 2, a fuel cell having the film-integrated gasket of this embodiment is described. Generally, a fuel cell is constructed as a battery pack consisting of a plurality of single cells. Figure 2 In FIG, a cross-sectional view of a portion of a battery pack composed of a plurality of single cells is shown. The battery pack is constructed by alternately stacking thin film integrated gaskets 100 and diaphragms 200 integrally provided with MEA (Membrane Electrode Assembly) 110. The single cell 10 is composed of the thin film integrated gasket 100 and a pair of diaphragms 200 provided on both sides thereof. Figure 2 In FIG, only one single cell is shown.

[0041] MEA 110 includes an electrolyte membrane 111 and a pair of gas diffusion layers 112 disposed on both surfaces of electrolyte membrane 111. Separator 200 also has flow paths (not shown) formed on the surface facing gas diffusion layers 112 for flowing fuel gas, oxidant gas, coolant, and the like.

[0042] In this embodiment, a resin film 120 is integrally provided with the MEA 110 to reinforce the electrolyte membrane 111. The resin film 120 is composed of a pair of films 121 and 122, and supports both surfaces of the electrolyte membrane 111. Preferred materials for the resin film 120 include resin materials such as PEN (polyethylene naphthalate) and PI (polyimide).

[0043] Furthermore, to prevent leakage of fuel gas, oxidant gas, coolant, and the like, a first gasket 131 and a second gasket 132 are provided between the resin film 120 and the diaphragm 200. In this embodiment, the first gasket 131 and the second gasket 132 are integrally provided on the resin film 120. Thus, the component in which the first gasket 131 and the second gasket 132 are integrally provided on the resin film 120 can be referred to as a "film-integrated gasket." Preferred materials for the first gasket 131 and the second gasket 132 include rubber materials such as EPDM (ethylene propylene diene monomer) and VMQ (vinyl methyl silicone rubber).

[0044] <Film integrated gasket>

[0045] The film-integrated gasket 100 included in the fuel cell will now be described in more detail. As described above, the film-integrated gasket 100 includes the MEA 110 and a resin film 120 integrally provided with the MEA 110. Furthermore, multiple manifolds 101 are provided on the resin film 120. The manifolds 101 are provided to distribute fuel gas, oxidant gas, coolant, and the like to the individual cells.

[0046] Furthermore, in order to prevent the above-mentioned fuel gas etc. from leaking to the outside, a first gasket 131 and a second gasket 132 are provided integrally with the resin film 120 around the area where the MEA 110 is provided and around the manifold 101. Figure 1 In FIG. 1 , the portion where the second gasket 132 is provided is indicated by a thick line.

[0047] The first gasket 131 is integrally provided with the resin film 120 on one surface of the resin film 120. Furthermore, the second gasket 132 is integrally provided with the resin film 120 on the other surface of the resin film 120, i.e., on the front and back sides of the first gasket 131, along the first gasket 131. However, depending on the structure of the battery pack, the second gasket 132 may be provided on the front and back sides of the entire area where the first gasket 131 is provided, or may be provided on the front and back sides of a portion of the area. Furthermore, the width W1 of the first gasket 131 on the resin film 120 side, which is perpendicular to the direction in which the first gasket 131 extends, is configured to be narrower than the width W2 of the second gasket 132 on the resin film 120 side, which is perpendicular to the direction in which the second gasket 132 extends. Furthermore, the center of the width W2 of the second gasket 132 is configured to be located on the front and back sides of the center of the width W1 of the first gasket 131, with the resin film 120 interposed therebetween. However, the present invention does not exclude the possibility that the center of W2 is located directly opposite or opposite to the center of W1, with the resin film 120 interposed therebetween. Furthermore, to improve sealing, the first gasket 131 in this embodiment has a sealing protrusion 131a on the side that contacts the diaphragm 200. The width of the sealing protrusion 131a is narrower than the width W1 on the side of the resin film 120. The second gasket 132 is also provided with a similar sealing protrusion 132a.

[0048] <Method for Manufacturing Thin Film Integrated Gasket>

[0049] Reference Figure 3 The method for manufacturing the film-integrated gasket 100 according to this embodiment will now be described. In this embodiment, the method includes: an insert molding step (a first step) of molding a first gasket 131 using a resin film 120 as an insert component; and an insert molding step (a second step) of molding a second gasket 132 using the resin film 120 integrally provided with the first gasket 131 as an insert component.

[0050] Figure 3(a) shows the first process. The mold for insert molding used in the first process includes a first lower mold 310 and a first upper mold 320. A first cavity 321 for molding the first gasket 131 is provided in the first upper mold 320. Regarding the first lower mold 310, at least the portion opposite to the first cavity 321 of the first upper mold 320 in the upper surface is composed of a plane. Using the mold constructed as above, the mold is closed with the resin film 120 arranged between the first lower mold 310 and the first upper mold 320. Then, the molding material is filled in the first cavity 321 to mold the first gasket 131.

[0051] After the above first step, the mold is opened and the resin film 120 integrally molded with the first spacer 131 is taken out.

[0052] Figure 3 (b) shows the second process. The mold for insert molding used in the second process includes a second lower mold 330 and a second upper mold 340. A second cavity 341 for molding the second gasket 132 is provided in the second upper mold 340. In addition, a groove 331 for configuring the first gasket 131 is provided in the second lower mold 330. Using the mold constructed as above, the mold is closed in a state in which a resin film 120 integrally provided with the first gasket 131 is arranged between the second lower mold 330 and the second upper mold 340. In addition, the mold is closed in a state in which the first gasket 131 is arranged in the groove 331. After the mold is closed, the molding material is filled in the second cavity 341 to mold the second gasket 132.

[0053] After the second step, the mold is opened to remove the resin film 120 integrally formed with the first gasket 131 and the second gasket 132. Afterwards, post-processing such as deburring is performed as needed to obtain the film-integrated gasket 100.

[0054] Here, the opening width of the first cavity 321 of the first upper mold 320 on the resin film 120 side, in a direction perpendicular to the extension direction of the first cavity 321, is referred to as a first opening width W32. Furthermore, the opening width of the second cavity 341 of the second upper mold 340 on the resin film 120 side, in a direction perpendicular to the extension direction of the second cavity 341, is referred to as a second opening width W34. Furthermore, the opening width of the groove 331 of the second lower mold 330 on the resin film 120 side, in a direction perpendicular to the extension direction of the groove 331, is referred to as a third opening width W33.

[0055] Thus, the first opening width W32 is less than the second opening width W34. Furthermore, the width W1 of the first gasket 131 molded by the first cavity 321 is substantially equal to the first opening width W32. Furthermore, the width W2 of the second gasket 132 molded by the second cavity 341 is substantially equal to the second opening width W34.

[0056] In addition, in this embodiment, the second opening width W34 is configured to satisfy the third opening width W33. Furthermore, the center of the third opening width W33 is located at the front and back sides of the center of the second opening width W34 via the resin film 120 (see Figure 3 (b)).

[0057] <Advantages of the Method for Manufacturing the Thin-Film Integrated Gasket According to the Present Embodiment>

[0058] According to the manufacturing method involved in this embodiment, it is configured to satisfy the first opening width W32 < the second opening width W34. As a result, the groove width (third opening width W33) of the groove 331 in the second lower mold 330 can be narrowed. Therefore, the gap formed on the front and back sides of the two side parts of the second cavity 341 in the second upper mold 340 through the resin film 120 can be narrowed or eliminated. Therefore, it is possible to prevent the two side parts of the second cavity 341 in the second upper mold 340 from pressing the resin film 120 insufficiently. As a result, the generation of burrs and the leakage of molding material can be suppressed, thereby preventing poor molding.

[0059] Furthermore, in this embodiment, since the second opening width W34 ≥ the third opening width W33 is satisfied, no gap is generated on the front and back sides of both sides of the second cavity 341 in the second upper mold 340 through the resin film 120 .

[0060] Furthermore, in this embodiment, the second opening width W34 is configured to satisfy the third opening width W33, and the center of the third opening width W33 is located directly behind the center of the second opening width W34, with the resin film 120 interposed therebetween. Therefore, even when the second opening width W34 is set equal to the third opening width W33, no gap is formed on the front and back sides of the second cavity 341 in the second upper mold 340, with the resin film 120 interposed therebetween.

[0061] In this way, by forming no gap between the front and back sides of the second cavity 341 in the second upper mold 340 via the resin film 120 , the pressing force of the second cavity 341 in the second upper mold 340 on the resin film 120 can be sufficiently increased.

[0062] (other)

[0063] The above embodiment shows a configuration in which the second opening width W34 ≥ the third opening width W33 is satisfied. However, if at least the first opening width W32 < the second opening width W34 is satisfied, the groove width (third opening width W33) of the groove 331 in the second lower mold 330 can be narrowed. Therefore, compared to a configuration in which the first opening width W32 is equal to the second opening width W34, the gap formed between the front and back sides of the second cavity 341 in the second upper mold 340 through the resin film 120 can be narrowed, thereby preventing molding defects.

[0064] Furthermore, this embodiment illustrates a case where the second opening width W34 ≥ the third opening width W33 is satisfied, and the center of the third opening width W33 is located directly behind the center of the second opening width W34, with the resin film 120 interposed therebetween. If the center of the opening width is not positioned in this manner, a gap can be formed directly behind one side of the second cavity 341 in the second upper mold 340, with the resin film 120 interposed therebetween. However, if the second opening width W34 ≥ the third opening width W33 is satisfied, this gap can be narrowed, thereby preventing molding defects.

[0065] In this embodiment, a thin-film integrated gasket used in a fuel cell is shown as an example. However, the thin-film integrated gasket of the present invention is not limited to use in fuel cells and can be applied to a variety of devices. Furthermore, the material of the thin film is not limited to resin. In particular, the present invention can be suitably applied to methods for manufacturing thin-film integrated gaskets composed of highly flexible thin films.

[0066] Explanation of symbols:

[0067] 10 single cells

[0068] 100 film integrated gasket

[0069] 101 Manifold

[0070] 110 MEA

[0071] 111 Electrolyte Membrane

[0072] 112 Gas Diffusion Layer

[0073] 120 resin film

[0074] 121, 122 film

[0075] 131 First Gasket

[0076] 131a Sealing protrusion

[0077] 132 Second gasket

[0078] 132a Sealing protrusion

[0079] 200 diaphragm

[0080] 310 first lower die

[0081] 320 First upper die

[0082] 321 First Cavity

[0083] 330 Second lower die

[0084] 331 slots

[0085] 340 Second upper die

[0086] 341 Second Cavity

[0087] W32 First opening width

[0088] W33 Third opening width

[0089] W34 Second opening width

Claims

1. A method for manufacturing a thin film integrated gasket, wherein the thin film integrated gasket has a first gasket integrally provided on one surface of a thin film, and a second gasket integrally provided along the first gasket on the other surface of the thin film, i.e., at a position opposite to the first gasket and on a back surface thereof, the manufacturing method is characterized in that: include: In the first step, the film is arranged between the first lower mold and the first upper mold, the first lower mold and the first upper mold having a first cavity for forming the first gasket are clamped together, and the first cavity is filled with a molding material to form the first gasket; as well as In the second step, the film integrally provided with the first gasket is arranged between the second lower mold and the second upper mold, and the second lower mold having a groove for arranging the first gasket and the second upper mold having a second cavity for molding the second gasket are clamped together, and the molding material is filled into the second cavity to mold the second gasket. The first opening width of the film side in the first cavity in a direction perpendicular to the extension direction of the first cavity is narrower than the second opening width of the film side in the second cavity in a direction perpendicular to the extension direction of the second cavity. The film has softness.

2. The method for manufacturing a thin film integrated gasket according to claim 1, wherein: The second opening width is equal to or greater than a third opening width of the groove on the film side in a direction perpendicular to the extending direction of the groove.

3. The method for manufacturing a thin film integrated gasket according to claim 2, wherein: The center of the third opening width is located directly behind the center of the second opening width with the film interposed therebetween.

4. The method for manufacturing a thin film integrated gasket according to claim 1, 2 or 3, wherein: The film is a resin film that reinforces an electrolyte membrane provided in a fuel cell.

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