Molding die for seal member and manufacturing method for the seal member

Abstract

To provide a molding die for a seal member, capable of suppressing the generation of a void that is in communication with the outside at the interface between a separator base material and a seal member, and provide a manufacturing method for the seal member.SOLUTION: A molding die 10 for a seal member according to the present disclosure is a molding die for a seal member for a fuel battery. The molding die comprises: an upper mold 11 having a convex part 111; and a lower molding 12 having a concave part 121 to be filled with the seal member 122. The upper molding comprises an injection port that injects the seal member. The convex part has a width and a height that are smaller than those of the convex part in a cross-sectional view.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a molding die for a seal member and a manufacturing method for the seal member, and more particularly to a molding die for a seal member for bonding separators to a fuel cell and a manufacturing method for the seal member. [Background technology]

[0002] Fuel cells use cells, each of which has an electrode member sandwiched between separators, as a power generation unit. The separators are pre-attached with a sealing member, and by using separators that are integrated with the sealing member, the cell formation process can be simplified and manufacturing costs can be reduced.

[0003] Patent Document 1 discloses a method for producing a plate with a seal, which employs a transfer process in which a seal member is injection molded, the seal member is joined to a separator substrate, and the seal member and separator substrate are heated and vulcanized to bond them together. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-181551 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the transfer process in which the seal member and the separator substrate are joined and heated and vulcanized to bond them, gaps may form between the separator substrate and the seal member, and voids may form at the interface between the separator substrate and the seal member due to the air in the gaps. Furthermore, if the voids communicate in the width direction of the seal member, hydrogen or air may leak to the outside through the communicated voids, causing problems such as a decrease in adhesion.

[0006] The present disclosure has been made to solve such problems, and aims to provide a molding die for a sealing member and a method for manufacturing a sealing member that can suppress the occurrence of voids communicating with the outside at the interface between a separator substrate and a sealing member. [Means for solving the problem]

[0007] The molding die for a sealing member according to the present disclosure is a molding die for a sealing member for a fuel cell, the molding die comprising an upper die having a convex portion and a lower die having a concave portion into which the sealing member is filled, the upper die having an injection port for injecting the sealing member, the convex portion having a width and height smaller than those of the concave portion in a cross-sectional view, and by adopting this configuration, it is possible to suppress the generation of voids communicating with the outside at the interface between the separator substrate and the sealing member.

[0008] The protruding portion of the molding die may be disposed at a center of the sealing material filled in the recessed portion, thereby making it possible to concentrate voids in the center of the sealing material.

[0009] Furthermore, the convex portion of the molding die may have any one of an inverted triangle, a trapezoid, and a circular arc shape, which makes it possible to efficiently concentrate voids in the center of the seal member.

[0010] The method of manufacturing a sealing member according to the present disclosure is a method of manufacturing a sealing member for a fuel cell, which comprises injection molding a material for the sealing member into a molding die, placing a separator on the sealing member, the molding die comprising an upper die having a convex portion and a lower die having a concave portion into which the sealing member is filled, the upper die having an injection port for injecting the sealing member, the convex portion having a width and height smaller than those of the concave portion in a cross-sectional view, and by doing so, it is possible to suppress the generation of voids communicating with the outside at the interface between the separator substrate and the sealing member. Effect of the Invention

[0011] The present disclosure makes it possible to provide a molding die for a seal member and a method for manufacturing a seal member that can suppress the occurrence of voids communicating with the outside at the interface between a separator substrate and a seal member. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a cross-sectional view of a molding die for the seal member according to the present disclosure. [Diagram 2] 5A to 5C are diagrams illustrating steps of a method for manufacturing a sealing member according to the present disclosure. [Diagram 3] 4 is a flowchart of a method for manufacturing a seal member according to the present disclosure. [Figure 4] FIG. 2 is a diagram illustrating the occurrence of voids according to the present disclosure. [Diagram 5] 13A and 13B are diagrams illustrating modified examples of the protrusions according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An example of the configuration of a molding die for a seal member according to the present disclosure will be described with reference to Fig. 1. The molding die 10 shown in Fig. 1 includes at least an upper die 11 having a convex portion 111 and a lower die 12 having a concave portion 121. The molding die 10 may include one or more convex portions 111 and concave portions 121, but it is preferable that they are the same in number.

[0014] The recess 121 is provided along the desired shape to be formed by the molding die 10, and the protrusion 111 is provided along the shape of the recess 121. Moreover, it is preferable that the width and height of the protrusion 111 in a cross-sectional view are smaller than the width and height of the recess 121, and therefore, it is preferable that the surface of the protrusion 111 is not in contact with the inner wall of the recess 121 when the upper die 11 and the lower die 12 are fitted together.

[0015] Moreover, it is preferable that the protrusion 111 is disposed in the center of the sealing material when the recess 121 is filled with a sealing material described later and the upper mold 11 and the lower mold 12 are fitted together. By disposing it in this manner, it is possible to efficiently suppress the occurrence of voids communicating with the outside.

[0016] A method for manufacturing a seal member according to the present disclosure will be described with reference to the explanatory diagram of FIG. 2 and the flow chart of FIG. 3. First, as shown in FIG. 2(a), in a state in which the upper mold 11 and the lower mold 12 of the molding die 10 are fitted together, a material such as uncrosslinked rubber that will become the seal member 122 is filled into the recess 121 of the lower mold 12 (S101). It is preferable to fill the seal member 122 by injection molding with an injection port (not shown) provided at an arbitrary position of the upper mold 11 of the molding die 10. The injection port may be provided in the protruding portion 111, or a part of the protruding portion 111 may be removed and an injection port provided at that position. Also, uncrosslinked rubber may be used for the seal member 122.

[0017] 2(b), the upper die 11 and the lower die 12 of the molding die 10 are opened, thereby forming a seal member 123 having a groove formed by the protrusion 111 (S102).

[0018] Next, as shown in Fig. 2(c), the separator substrate 20 is placed on the lower mold 12 and the seal member 123 having a groove (S103), and a second upper mold 13 without a protrusion 111 is prepared and pressed against the surface of the separator substrate 20. Thereafter, as shown in Fig. 2(d), a heat treatment is performed to crosslink the uncrosslinked rubber in the seal member 123 having a groove, and the seal member 123 having a groove and the separator substrate 20 are bonded together (S104). This forms the separator 21 shown in Fig. 2(e).

[0019] Finally, the separator 21 is released from the molding die 10 (S105).

[0020] The mechanism by which the molding die 10 according to the present disclosure suppresses the generation of voids will be described with reference to Fig. 4. Fig. 4(a) shows the state of the molding die 10, separator substrate 20, and seal member 123 having a groove when the separator substrate 20 is placed in step S103, and Fig. 4(b) shows the state of the molding die 10, separator substrate 20, and seal member 123 having a groove when the heat treatment is performed in step S104. Figs. 4(c) and (d) show enlarged views of the areas indicated by the dotted circles in Figs. 4(a) and (b), respectively.

[0021] 4(c), when the separator substrate 20 is installed, air gets mixed in between the seal member and the separator substrate, creating a gap. When the seal member expands due to heat treatment, the gap becomes a void 130, and there is a possibility that hydrogen or air may leak to the outside through the void 130.

[0022] By using the molding die 10 according to the present disclosure, a groove is formed inside the seal member, so that air is concentrated in the direction of the groove, i.e., the direction of the arrow in Figures 4(b) and (d), during heat treatment. Therefore, the generation of voids 130 can be suppressed.

[0023] The separator 21 obtained in this manner has voids 130 concentrated in the grooves (see Figure 4(e)), which means that the voids 130 do not communicate with each other in the width direction, and this makes it possible to suppress a decrease in adhesion, making the separator 21 suitable for use as a sealing material for fuel cells.

[0024] In the above description, the shape of the upper mold 11 is an inverted triangle as shown in Fig. 1 and Fig. 5(a), but the present disclosure is not limited to this. For example, the shape of the upper mold 11 may be a trapezoid as shown in Fig. 5(b), or a circular arc as shown in Fig. 5(c).

[0025] In this way, it is possible to provide a molding die for a seal member and a method for manufacturing a seal member that can suppress the occurrence of voids communicating with the outside at the interface between the separator substrate and the seal member.

[0026] It should be noted that the present disclosure is not limited to the above and can be modified as appropriate without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0027] 10. Molding tool 11 Upper mold 12 Lower mold 13 Second upper die 20 Separator substrate 21 Separator 111 Convex 121 Recess 122 Sealing material 123 Sealing member with groove 130 Void

Claims

1. A molding die for a sealing member for a fuel cell, comprising: The molding die includes an upper die having a convex portion and a lower die having a concave portion into which a sealing material is filled, the upper mold has an injection port for injecting the seal member, The protrusion has a width and a height smaller than those of the recess in a cross-sectional view. A molding die for sealing materials.

2. The protrusion is disposed at the center of the sealing material filled in the recess. A mold for molding the seal member according to claim 1.

3. The convex portion has any one of an inverted triangle, a trapezoid, and a circular arc shape. A mold for molding the seal member according to claim 1.

4. A method for manufacturing a sealing member for a fuel cell, comprising the steps of: The material of the seal member is injected into the mold; A separator is placed on the sealing member; The molding die includes an upper die having a convex portion and a lower die having a concave portion into which a sealing material is filled, the upper mold has an injection port for injecting the seal member, The protrusion has a width and a height smaller than those of the recess in a cross-sectional view. A method for manufacturing a seal member.

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