JP2010146979A - Gasket structure and fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasket structure which can prevent a load on a power generation cell from varying even when a pitch of the power generation cells fluctuates. <P>SOLUTION: The gasket structure 200 is arranged around an opening 110 formed on the power generation cell 20. A first distance L2 between a first contact part 170 contacting the first power generation cell 20 and the opening 110 is different from a second distance L3 between a second contact part 120 contacting the second power generation cell 20 and the opening 110. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell, and more particularly to a gasket structure.

  In a fuel cell, a gasket is provided between the separator and the separator in order to suppress leakage of the reaction gas from between the separator and the separator (for example, Patent Document 1).

JP2008-243799A

  By the way, when the fuel cell is operated for a long time, the total length of the fuel cell stack may fluctuate and the pitch of the power generation cells may fluctuate. In addition, due to an external impact, the power generation cell may shift and the power generation cell pitch may vary. In the prior art, when the pitch of the power generation cell varies, there is a problem that the load applied to the power generation cell varies greatly.

  An object of the present invention is to solve at least one of the above-described problems and to provide a gasket structure in which the load applied to the power generation cell does not easily change even if the pitch of the power generation cell varies.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A gasket structure disposed around an opening formed in the power generation cell, wherein the first distance between the first end contacting the first power generation cell and the opening is the second power generation cell. A gasket structure, comprising a gasket member that is different from a second distance between the second end and the opening.
When a load is applied to the power generation cell, the gasket is deformed and a reaction force is generated. According to this application example, if the deformation range of the gasket is a certain range, the change in the reaction force is smaller than when the O-ring is used. Therefore, it is possible to provide a gasket structure in which the load applied to the power generation cell does not easily vary even if the pitch of the power generation cell varies.

[Application Example 2]
In the gasket structure described in Application Example 1,
The gasket structure is a gasket structure in which a cross-sectional shape when cut along a direction penetrating the opening has a square shape.
According to this application example, the first distance between the first contact portion in contact with the first power generation cell and the opening is equal to the second contact portion in contact with the second power generation cell and the opening. It is possible to easily realize the difference from the second distance.

[Application Example 3]
In the gasket structure according to Application Example 1 or Application Example 2, the gasket member includes a core material formed of a hard material and a seal material formed of a soft material that wraps the core material.
Gasket structure.
According to this application example, the reaction force against the power generation cell can be generated using the restoring force against the deformation of the hard material. Further, the sealing property is ensured by the contact between the sealing material and the power generation cell.

[Application Example 4]
4. The gasket structure according to any one of application examples 1 to 3, wherein the power generation cell includes a concavo-convex shape for positioning the gasket member at a portion in contact with the gasket member.
According to this application example, it is possible to suppress the lateral displacement of the gasket.

[Application Example 5]
4. The gasket structure according to any one of application examples 1 to 3, wherein the gasket member is formed integrally with a separator provided between the first and second power generation cells. .
According to this application example, since the gasket and the separator can be formed integrally, the number of components can be reduced.

  In addition, this invention can be implement | achieved with various forms, for example, can be implement | achieved with various forms, such as a fuel cell other than a gasket structure.

  FIG. 1 is an explanatory diagram showing a fuel cell stack. The fuel cell stack 10 includes a power generation cell 20, an end plate 30, a tension rod 40, and a nut 50. There are a plurality of power generation cells 20 stacked. The configuration of the power generation cell 20 will be described later. The end plates 30 are disposed on both sides of the stacked power generation cells 20. The tension rod 40 and the nut 50 fix the distance between the two end plates 30 to a certain length (L1). Thereby, a fixed fastening load is applied to the power generation cell 20.

  FIG. 2 is an explanatory view showing a plan view of the separator and the gasket. In the same figure, the separator 100 and the gasket 200 arrange | positioned on it are drawn. The separator 100 is a member arranged on one surface of the power generation cell 20. A separator 150 (not shown in the figure) is disposed on the other surface of the power generation cell 20. The separator 100 has a substantially rectangular shape, and includes a plurality of openings 110 at the outer edge. The opening 110 forms a manifold for supplying and discharging fuel gas, oxidizing gas, and refrigerant. The gasket 200 is disposed around the opening 110.

  FIG. 3 is an explanatory diagram showing a cross section taken along line 3-3 in FIG. The cross section shown in the figure is a cross section cut along a cutting line perpendicular to the longitudinal direction of the opening 110. The power generation cell 20 includes separators 100 and 150, an electrolyte membrane 300, a gas diffusion layer 310, and a frame 400. The electrolyte membrane 300 is a membrane for moving protons generated at the anode electrode to the cathode electrode. As the electrolyte membrane 300, for example, a proton conductive ion exchange membrane made of a fluorine resin such as perfluorocarbon sulfonic acid polymer or a hydrocarbon resin can be used. A catalyst layer (not shown) is formed on both surfaces of the electrolyte membrane 300. As the catalyst, for example, a platinum catalyst or a platinum alloy catalyst made of platinum and another metal can be used. The catalyst is supported on, for example, carbon particles and applied to the surface of the electrolyte membrane 300 to form a catalyst layer. The gas diffusion layer 310 is disposed on both surfaces of the electrolyte membrane 300. As the gas diffusion layer 310, carbon cloth or carbon paper using a carbon nonwoven fabric can be used. In addition, as the gas diffusion layer 310, a porous body made of metal or resin can be used. The frame 400 is formed at the outer edge of the electrolyte membrane 300 and supports the electrolyte membrane 300. The frame 400 is made of, for example, resin or rubber.

  The separators 100 and 150 are disposed outside the gas diffusion layer 310. Separator 100,150 has an uneven shape in the center. Hereinafter, with respect to the concavo-convex shape of the separators 100 and 150, portions protruding to the side opposite to the electrolyte membrane 300 are referred to as convex portions 102 and 152, respectively, and portions protruding to the electrolyte membrane 300 side when viewed from the convex portions 102 and 152 are respectively concave portions. 103 and 153. The convex part 102 of the separator 100 and the convex part 152 of the separator 150 are in contact with each other, and the separator 100 and the separator 150 are electrically connected. A reactive gas flow channel 500 is formed between the convex portion 102 of the separator 100 and the gas diffusion layer 310, and a reactive gas flow channel 510 is formed between the convex portion 152 of the separator 150 and the gas diffusion layer 310. Has been. A coolant channel 520 is formed between the recess 103 of the separator 100 and the recess 153 of the separator 150.

  A gasket 200 is disposed between the outer edge portions of the separator 100 and the separator 150. In the cross section shown in the figure, the gasket 200 is cut along the direction penetrating the opening 110, and the cross section has a C-shape. Both end portions of the gasket 200 are in contact with the separators 100 and 150, respectively.

  FIG. 4 is an explanatory view showing the vicinity of the gasket of FIG. 3 in an enlarged manner. The gasket 200 includes a core material 210 and a seal material 220. The core material 210 is made of, for example, a hard elastic material such as metal. The reason why a hard material is used for the core material 210 is to generate a reaction force against the separators 100 and 150 using a restoring force against deformation of the hard material. The sealing material 220 is provided so as to cover the core material 210. The sealing material 220 is formed of a soft material that is softer than the core material. The reason why the soft material is used for the sealing material 220 is to improve the sealing effect by bringing the sealing material 220 into contact with the separators 100 and 150. For example, rubber or resin can be used as the sealing material 220. Note that the sealing material 200 may be omitted.

  Both ends of the gasket 200 are in contact with the separators 100 and 150. When the power generation cell 20 is fastened, the gap between the separators 100 and 150 is narrowed, so that the gasket 200 is deformed in a flattening direction. As a result, the gasket generates a reaction force between the gasket 200 and the separator 100 and between the gasket 200 and the separator 150 in an attempt to return to the original oblique shape. This reaction force seals between the gasket 200 and the separator 100, and between the gasket 200 and the separator 100, and suppresses leakage of reaction gas and refrigerant.

  FIG. 5 is an explanatory view showing a cross section taken along line 5-5 in FIG. The cross section shown in the figure is a cross section cut along a cutting line parallel to the longitudinal direction of the opening 110. Also in this cut surface, the gasket 200 has an inclined surface in which the shape of the two inclined surfaces sandwiching the opening 110 is a square shape.

  FIG. 6 is an explanatory view showing a contact portion of the separator with the gasket. The contact portion 120 between the separator 100 and the gasket 200 and the contact portion 170 between the separator 150 and the gasket 200 all have a rectangular frame shape. Further, the interval L3 between the opening 110 and the contact portion 120 is larger than the interval L2 between the opening 110 and the contact portion 170. By doing so, it is possible to make the shape of the gasket 200 in the cross section along the 3-3 cutting line in FIG. 2 and the shape of the gasket 200 in the cross section along the 3-3 cutting line both into a square shape. Become.

  FIG. 7 is an explanatory diagram showing the relationship between the amount of deformation of the gasket and the load applied to the power generation cell. In the figure, the characteristics when the gasket 200 of the present embodiment is used and the characteristics when an O-ring is used as the gasket are shown. When an O-ring is used as the gasket, the load applied to the power generation cell 20 is suddenly reduced as the amount of deformation of the gasket decreases. On the other hand, when the amount of deformation of the gasket increases, the load applied to the power generation cell 20 suddenly increases. On the other hand, in this embodiment, even if the deformation amount of the gasket 200 is reduced (even if the pitch of the power generation cell is increased), the load applied to the power generation cell 20 is maintained within a certain range within a certain range. The On the contrary, even if the deformation amount of the gasket 200 increases (even if the pitch of the power generation cell decreases), the load applied to the power generation cell 20 is maintained within a certain range within a certain range. That is, even if the pitch of the power generation cells 20 varies, it is possible to make it difficult for the load applied to the power generation cells 20 to vary within a certain range. Thereby, the fluctuation | variation of the power generation efficiency of the fuel cell stack 10 can be suppressed, and the fuel cell stack 10 can output a stable power generation output. In this way, even if the pitch of the power generation cell 20 varies, if the variation amount is within a certain range, in order to make it difficult for the load applied to the power generation cell 20 to vary, the gasket 200 has a disc spring characteristic. It is preferable to provide. However, as the gasket 200, it is possible to adopt a gasket having a smaller variation in load (reaction force) than an O-ring.

  FIG. 8 is an explanatory view showing an example of a gasket manufacturing process. In the step (A), a metal flat plate is punched with a press to form a frame-shaped core material 210. Next, in the step (B), the core material 210 is wrapped with the sealing material 220. Next, in step (C), it is deformed by pressing so that the opposing sides have a square shape. In this manufacturing method, the core material 210 is wrapped with the sealing material 220 before being deformed into a square shape. Therefore, the process of wrapping the core material 210 with the sealing material 220 can be easily performed.

  FIG. 9 is an explanatory view showing another example of the gasket manufacturing process. In the step (A), a metal flat plate is punched out using a press to form a frame-shaped core material 210. Next, at a process (B), it deform | transforms so that the edge | side to oppose may become a square shape by press. Next, in the step (C), the core material 210 is wrapped with the sealing material 220. In this manufacturing method, before the core material 210 is wrapped with the seal material 220, the core material 210 is deformed into a square shape. If it carries out like this, since the core material 210 will be deform | transformed in the state of a single item, the processing precision in a deformation | transformation can be raised. In addition, you may perform a process (A) and a process (B) simultaneously.

  FIG. 10 is an explanatory view showing another example of the shape of the gasket. In FIG. 4A, the gasket 200 has a V-shape. The gasket 200 may have an inverted V shape. In FIG. 5B, the gasket 200 has an inverted U shape. Note that the gasket 200 may have a U-shape. Thus, by making the shape of the gasket 200 V-shaped or U-shaped, the gasket 200 can be provided with a disc spring characteristic. As a result, even if the pitch of the power generation cell 20 varies, it is possible to make it difficult to vary the load applied to the power generation cell 20 within a certain range. In addition, the V-shaped or U-shaped configuration can increase the rigidity of the gasket 200 as compared to the C-shaped configuration.

  As described above, according to the present embodiment, the gap L3 between the opening 110 and the contact portion 120 is configured to be larger than the gap L2 between the opening 110 and the contact portion 170. It can be shaped like a letter. As a result, even if the gasket 200 is deformed, the load applied to the power generation cell 20 can be maintained within a certain range. The shape of the gasket 200 is not limited to the C-shape, and may be a V-shape or a U-shape.

  FIG. 11 is an explanatory diagram showing the second embodiment. In the second embodiment, the separators 100 and 150 are provided with concave and convex shapes 104 and 105 and 154 and 155 at portions in contact with the gasket 200, respectively. The uneven shape 104, 105, 154, 155 facilitates the positioning of the gasket 200. Further, the lateral displacement of the gasket 200 can be suppressed. Note that it is not necessary for both the separators 100 and 150 to have the concavo-convex shapes 104, 105 or 154, 155, and only one of the separators has to have the concavo-convex shape. Further, the separators 100 and 150 may include only the inner uneven shapes 104 and 154, or may include only the outer uneven shapes 105 and 155.

  FIG. 12 is an explanatory diagram showing the third embodiment. In the third embodiment, an independent gasket 200 is not provided between the separators 100 and 150. Instead, a part around the opening 110 of the separator 100 is bent to the outside of the power generation cell 20, thereby forming the gasket portion 106. The gasket portion 106 is wrapped with a sealing material 220. In other words, the third embodiment has a structure in which the gasket 200 and the separator 100 shown in the first embodiment are integrated. Even if it comprises in this way, even if the pitch of the power generation cell 20 fluctuates, if the fluctuation amount is within a certain range, it is possible to suppress the fluctuation of the load applied to the power generation cell 20. Further, the gasket structure can be formed simultaneously with the molding of the separator 100. Furthermore, in this embodiment, since the independent gasket 200 is not used, it is possible to reduce the number of parts.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

It is explanatory drawing which shows a fuel cell stack. It is explanatory drawing which shows the top view of a separator and a gasket. It is explanatory drawing which shows the cross section by the 3-3 cutting line in FIG. It is explanatory drawing which expands and shows the vicinity of the gasket of FIG. It is explanatory drawing which shows the cross section by the 5-5 cutting line in FIG. It is explanatory drawing which shows a contact part with the gasket of a separator. It is explanatory drawing which shows the relationship between the deformation amount of a gasket, and the load concerning a power generation cell. It is explanatory drawing which shows an example of the manufacturing process of a gasket. It is explanatory drawing which shows another example of the manufacturing process of a gasket. It is explanatory drawing which shows the example of the other shape of a gasket. It is explanatory drawing which shows a 2nd Example. It is explanatory drawing which shows a 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 20 ... Power generation cell 30 ... End plate 40 ... Tension rod 50 ... Nut 100 ... Separator 102 ... Convex part 103 ... Concave part 104, 105 ... Concave shape 106 ... Gasket part 110 ... Opening part 120 ... Contact part 150 ... Separator 152 ... convex part 153 ... concave part 170 ... contact part 200 ... gasket 210 ... core material 220 ... sealing material 300 ... electrolyte membrane 310 ... gas diffusion layer 400 ... frame 500 ... reaction gas flow path 510 ... reaction gas flow path

Claims (6)

A gasket structure disposed around an opening formed in the power generation cell,
A gasket in which a first distance between the first end contacting the first power generation cell and the opening is different from a second distance between the second end contacting the second power generation cell and the opening. A gasket structure comprising a member. The gasket structure according to claim 1,
The gasket structure is a gasket structure in which a cross-sectional shape when cut along a direction penetrating the opening has a square shape. In the gasket structure according to claim 1 or 2,
The gasket member is
A core material made of hard material,
A sealing material formed of a soft material that wraps around the core material,
Gasket structure. In the gasket structure according to any one of claims 1 to 3,
The said power generation cell is a gasket structure provided with the uneven | corrugated shape for positioning of the said gasket member in the part which contacts the said gasket member. The gasket structure according to any one of claims 1 to 3,
The gasket structure, wherein the gasket member is formed integrally with a separator provided between the first and second power generation cells. A fuel cell,
A power generation cell;
A fuel cell comprising the gasket structure according to any one of claims 1 to 5.

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