JP2009099424A - Gasket member and fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gasket member capable of both reducing loads and avoiding adverse effects caused by lateral deviation at the same time, and to provide a fuel cell stack. <P>SOLUTION: The gasket member has a shoulder that is constituted of an elastic body and abuts a separator to receive a load from the separator, with the surface of the shoulder abutting the separator being formed in an uneven shape. Therefore, the coefficient of static friction μ of the surface of the shoulder abutting the separator increases, resulting in the shoulder being more resistant to lateral deviation than other shoulders having no uneven shape. Moreover, even if the load received by the gasket member is reduced, the lateral deviation of the gasket member can be preferably suppressed. The pressure received from the separator can also be dispersed to the projected portions, thus the shoulder has a width enough to achieve a sufficient capability as the shoulder and preferably maintains its sealing capability even during the lateral deviation. As described above, the gasket member has effects to avoid the adverse effects caused by the lateral deviation and at the same time to reduce the load being received. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gasket member and a fuel cell stack, and more particularly to a gasket member and a fuel cell stack that are less susceptible to lateral displacement while suppressing an increase in received load.

  In general, a unit cell of a polymer electrolyte fuel cell is composed of a membrane electrode assembly (MEA) and separators stacked on both sides of the membrane electrode assembly (MEA).

  The membrane electrode assembly is composed of an electrolyte membrane made of a solid polymer electrolyte membrane such as Nafion (registered trademark: manufactured by DuPont), a catalyst layer and a gas diffusion layer disposed on one surface of the electrolyte membrane, and an oxidant gas ( For example, a fuel electrode (for example, hydrogen gas) that includes an air electrode (cathode electrode) to which air is supplied and a catalyst layer and a gas diffusion layer disposed on the other surface of the electrolyte membrane (for example, hydrogen gas) is supplied. Anode electrode).

  When the separator is hermetically molded from a conductive material and laminated with the membrane electrode assembly interposed therebetween, an air chamber is formed on the air electrode side of the membrane electrode assembly, and the fuel chamber is formed on the fuel electrode side. Form. When the fuel cell stack is configured, the separators are common to adjacent unit cells.

  When a fuel cell is configured by laminating a membrane electrode assembly and a separator, the gas sealing property between the pair of separators is ensured by a gasket interposed between the pair of separators. As such a fuel cell gasket, for example, a gasket described in Patent Document 1 can be employed. Specifically, Patent Document 1 describes a gasket as a seal structure having a lip (seal lip) made of an elastic body protruding in the center and shoulder portions made of an elastic body formed on both sides of the lip. Has been.

The gasket of the type described in Patent Document 1 is deformed when a lip is pressed by a separator and exhibits a sealing function. On the other hand, the shoulder portions located on both sides of the lip support the lip from the side when the gasket is compressed by fastening the fuel cell stack, and prevent the lip from falling down, and face each other through one separator. A certain degree of positional deviation (for example, lateral deviation caused by vibration) generated between the lips is allowed and a sealing property is secured.
JP 2005-259398 A

  By the way, in the fuel cell stack, it is desirable from the viewpoint of power generation efficiency that the load (fastening load) applied to the gasket (sealing structure) is lower than the load applied to the membrane electrode assembly. However, the lower the load applied to the gasket, the easier it is to cause a lateral shift.

  Here, reduction of the load which a gasket receives can be achieved by narrowing the width | variety of a shoulder part, for example. However, as the width of the shoulder is narrowed, the function as the shoulder is not performed. That is, as the width of the shoulder portion is narrowed, the supporting force with respect to the lip is weakened, and the lip falls easily, and the allowable range for the lateral displacement becomes small, and it becomes difficult to ensure the sealing performance at the lateral displacement.

  As described above, conventional gaskets such as the gasket described in Patent Document 1 have a problem to be solved that occurs with a reduction in load when reducing the load that the gasket receives.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a gasket member and a fuel cell stack that can achieve both suppression of a load received and avoidance of an adverse effect due to lateral displacement.

  In order to achieve this object, the gasket member according to claim 1 includes a membrane electrode assembly having a solid polymer electrolyte membrane and a pair of electrode layers laminated on both surfaces of the solid polymer electrolyte membrane, and the membrane. Used in a fuel cell including a pair of separators provided on both surfaces of an electrode assembly and having a gas flow path for supplying gas to each electrode layer, and disposed between the membrane electrode assembly and the pair of separators. A gas sealing property is ensured, comprising a shoulder portion made of an elastic body that comes into contact with the separator and receives pressure from the separator, and the contact surface of the shoulder portion with the separator is uneven. It is configured.

  A gasket member according to a second aspect is the gasket member according to the first aspect, wherein the concave-convex shape is a suction structure recessed in a contact surface of the shoulder with the separator.

  The fuel cell stack according to claim 3 is provided on both sides of the membrane electrode assembly having a solid polymer electrolyte membrane and a pair of electrode layers laminated on both sides of the solid polymer electrolyte membrane. And a gasket member according to claim 1, wherein the gasket member is disposed between the membrane electrode assembly and the pair of separators. A plurality of fuel cell unit cells are stacked.

  According to the gasket member of claim 1, the shoulder portion made of an elastic body is in contact with the separator and receives pressure from the separator, and the contact surface with the separator is formed in an uneven shape. Has been.

  Therefore, since the static friction coefficient μ of the contact surface with the separator in the shoulder portion increases, it is difficult for lateral displacement to occur as compared with a shoulder portion having no uneven shape. Therefore, even if the load received by the gasket member is reduced, the lateral displacement of the gasket member can be suitably suppressed.

In addition, since the pressure received from the separator can be distributed to the formed convex portions, the load changes with respect to the crushing margin. Therefore, compared to a flat shoulder with no uneven shape,
Even if the width of the shoulder portion is wide (or the area of the contact surface with the separator is increased), the load can be easily controlled, and an excessive load can be suppressed. Accordingly, the shoulder portion can have a width that can sufficiently exhibit the function as the shoulder portion, and the sealing performance can be suitably ensured even during lateral displacement.

  As described above, according to the gasket member of the first aspect, since the contact surface with the separator in the shoulder portion is configured to be uneven, there is an effect that the load received can be suppressed while avoiding the adverse effects due to the lateral displacement. is there.

  According to the gasket member of the second aspect, in addition to the effect produced by the gasket member according to the first aspect, the following effect is obtained. Since the uneven shape formed on the contact surface of the shoulder with the separator is a suction structure recessed in the corresponding contact surface, there is an effect that lateral displacement can be more effectively prevented by suction due to negative pressure.

  Since the fuel cell stack according to the third aspect uses the gasket member according to the first or second aspect, the fuel cell stack has the same effect as the gasket member according to the first or second aspect.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an exploded perspective view showing a part of a fuel cell stack 100 in which a plurality of unit cells 10 of a fuel cell are stacked.

  As shown in FIG. 1, the fuel cell stack 100 has a structure in which a number of gasket members 40 in which membrane electrode assemblies 20 are integrated on the inner peripheral side and metal separators 60 are alternately stacked (in FIG. 1, Only three gasket members 40 and three metal separators 60 are shown). End plates (not shown) are arranged at both ends of the fuel cell stack 100 in the stacking direction, and both end plates are fastened using bolts (not shown) and nuts (not shown). By doing so, the gasket member 20 and the metal separator 60 which are laminated | stacked alternately are press-clamped.

  Here, the unit cell 10 of the fuel cell includes a membrane electrode assembly 20, a gasket member 40 disposed on the outer peripheral side of the membrane electrode assembly 20, and metal separators positioned on both sides of the membrane electrode assembly 20. 60. As shown in FIG. 1, one metal separator 60 is commonly used as a separator for adjacent unit cells 10.

  The membrane electrode assembly 20 includes a solid polymer electrolyte membrane 21 (see FIG. 2 (c)) such as Nafion (registered trademark: manufactured by DuPont) or Aciplex (registered trademark: manufactured by Asahi Kasei Co., Ltd.), and the solid polymer. It is comprised from a pair of electrode layers 22 and 23 (refer FIG.2 (c)) each laminated | stacked and joined on both surfaces of the electrolyte membrane.

  Both electrode layers 22 and 23 in the membrane electrode assembly 20 are each composed of a catalyst layer (not shown) and a gas diffusion layer (not shown), and the catalyst layer side is joined to the solid polymer electrolyte membrane. ing. These electrode layers are used as an air electrode (cathode electrode) or a fuel electrode (anode electrode) depending on the type of gas supplied. Hereinafter, the electrode layer 22 will be described as the air electrode 22, and the electrode layer 23 will be described as the fuel electrode 23.

  A gas diffusion layer (not shown) in the air electrode 22 and the fuel electrode 23 is composed of carbon woven fabric, carbon paper, or the like capable of gas diffusion. For example, carbon cloth, carbon paper, carbon fiber A nonwoven fabric made of or the like is used.

  In addition, as the catalyst layer (not shown) in the membrane electrode assembly 20, for example, a layer including carbon carrying a platinum catalyst and an electrolyte can be employed.

  Next, the gasket member 40 of this embodiment is demonstrated with reference to FIGS. 2A is a perspective view schematically showing one surface side of the gasket member 40 in which the membrane electrode assembly 20 is integrated on the inner peripheral side, and FIG. 2B is a perspective view of FIG. FIG. 2C is a perspective view schematically showing the back surface side of the gasket member 40 shown in FIG. 2, and FIG. 2C is a cross-sectional view taken along the line IIc-IIc in FIG. 2A and 2C, the detailed structure of the seal structures 45 and 51 is omitted for the purpose of facilitating understanding of the drawings.

  3 (a) is a front view of the portion viewed from the direction of arrow IIIa in FIG. 2 (a), and FIG. 3 (b) is a cross-sectional view taken along line IIIb-IIIb in FIG. 3 (a). 3 (c) is a front view of a portion viewed from the direction of arrow IIIc in FIG. 2 (a). For the purpose of facilitating understanding of the drawing, hatching is applied to the shoulder portions 45b and 45c in FIG. 3A and to the shoulder portions 51b and 51c in FIG. 3C.

  4A is an enlarged cross-sectional view schematically showing the seal structures 45 and 51, and FIG. 4B is an A portion in FIG. 4A, that is, shoulders 45c and 51c. It is an enlarged view of a front-end | tip part. 4B is an enlarged view of the tip portions of the shoulder portions 45c and 51c, the tip portions of the shoulder portions 45b and 51b have the same shape.

  The gasket member 40 is a member that is disposed on the outer peripheral side of the membrane electrode assembly 20 and ensures a gas sealing property between a pair of metal separators 60 that are disposed to face both surfaces thereof. The gasket member 40 includes an air electrode gasket 41 constituting one surface of the gasket member 40 and a fuel electrode gasket 42 constituting the other surface. The air electrode gasket 41 and the fuel electrode gasket 42 are made of an insulating elastic body such as rubber or resin, and are produced by injection molding the insulating elastic body into a corresponding shape.

  Here, an adhesive film sheet (not shown) that also serves as a reinforcing plate is disposed on one side of each gasket 41, 42 (the side to be bonded to each other), and these adhesive film sheets are opposed to each other. The gasket member 40 is manufactured by bonding the gaskets 41 and 42 together. The air electrode gasket 41 and the fuel electrode gasket 42 have openings 41a and 42a corresponding to the membrane electrode assembly 20, respectively. When the gasket member 40 is manufactured, the air electrode gasket 41 and the fuel electrode gasket 42 After the membrane electrode assembly 20 is interposed between the two, they are bonded. Therefore, the membrane electrode assembly 20 is fixed by the adhesive film sheet (not shown), and as a result, the gasket member 40 is obtained as the membrane electrode assembly 20 integrated on the inner peripheral side thereof.

  The gasket member 40 has openings 43 and 44 on both ends sandwiching the membrane electrode assembly 20. These openings 43 and 44 serve as flow paths through which fuel gas (for example, hydrogen gas) flows in the stacking direction of the fuel cell stack 100 (the arrow Z direction in FIG. 2A or the opposite direction). is there.

  In order to prevent fuel gas from leaking from the openings 43 and 44 to the air electrode 22 and the outside, a seal structure 45 is formed around the openings 43 and 44 in the air electrode gasket 41 of the gasket member 40. ing.

  The seal structure 45 includes a seal lip portion 45a, shoulder portions 45b and 45c positioned on both sides of the seal lip portion 45a in cross-sectional view (that is, the inner peripheral side and the outer peripheral side of the seal lip 45a), and the seal lip portion 45a. 45d formed between the shoulder portion 45b and the groove portion 45e formed between the seal lip portion 45a and the shoulder portion 45c. Such a sealing structure is composed of an insulating elastic body having a low hardness (for example, a hardness of about 40 to 50 degrees) so as to ensure a sealing property under a low load.

  The seal lip portion 45 a is a portion that exerts a gas seal function by being deformed by being pressed from the metal separator 60 facing when the fuel cell stack 100 is configured (stacking). The shoulder portions 45b and 45c, together with shoulder portions 51b and 51c described later, define the distance between the pair of metal separators 60 when the fuel cell stack 100 is configured (stacked), and support the seal lip 45a from the side. It serves to prevent lip collapse. The groove portions 45d and 45e are portions that function as escape portions of the insulating elastic body for allowing deformation of the seal lip portion 45a due to a compressive load.

  More specifically, the seal lip 45a has a sharp tapered tip such as a cross-sectional mountain shape or a triangular shape as shown in FIG. 4 (a) in order to satisfy the demand for long-term durability of the gas sealing function. In addition, the height of the shoulder portions 45b and 45c is higher than that of the shoulder portions 45b and 45c (that is, the tip portion is positioned higher than the shoulder portions 45b and 45c).

  As shown in FIG. 4A, the shoulder portions 45b and 45c can control the seal lip portion 45a to a desired compression rate (that is, the seal lip portion 45a can be controlled to a desired height with respect to the compression load). As such, both are configured to be lower than the height of the seal lip portion 45a and substantially the same height.

  In addition, since the front end portions of the shoulder portions 45b and 45c are wide, the lateral displacement of the gasket portion 40 can be allowed to some extent, and deterioration of the sealing performance due to the lateral displacement can be prevented within the allowable range.

  As shown in FIG. 4 (b), in the gasket member 40 of the present embodiment, the distal end portion of the wide shoulder portion 45 c is configured to have a concavo-convex shape having a large number of protruding convex portions 81. Although not shown, the shoulder portion 45b is also formed in a concavo-convex shape having a wide tip portion and a large number of protruding convex portions 81, like the shoulder portion 45c.

  Here, with reference to FIG. 5, the advantage by making the front-end | tip part of the shoulder parts 45b and 45c into uneven | corrugated shape is demonstrated. FIG. 5A is a graph showing the relationship between the crushing margin S of the shoulder portions 45b and 45c whose tip portions are formed in an uneven shape in this embodiment and the load F applied to the shoulder portions 45b and 45c having a width T. It is. FIG. 5 (b) shows a shoulder portion of a conventional gasket member as a comparative example, that is, a crushing margin S of a shoulder portion having a flat tip portion and a load F applied to the shoulder portion having a width T. It is a graph which shows a relationship.

  The horizontal axes of the graphs shown in FIG. 5A and FIG. 5B are axes indicating the shoulder crushing margin S, and indicate that the crushing margin S increases from left to right. On the other hand, the vertical axis is a phrase indicating the load F applied to the shoulder, and indicates that the load applied to the shoulder increases from the bottom to the top. For the purpose of facilitating understanding of the graph, an image of the seal structure 45 of the present embodiment (FIG. 5A) and an image of the conventional seal structure (FIG. 5B) are shown below each graph. And attached.

  As shown in FIG. 5B, when the tip of the shoulder is flat, the change in the load F with respect to the increase in the crushing margin S is abrupt, whereas as shown in FIG. In the case of the shoulder portions 45b and 45c whose tip portions are formed in a concavo-convex shape, the load F changes gradually as the crushing margin S increases.

  That is, the shoulder portions 45b and 45c of the seal structure 45 in the gasket member 40 of the present embodiment are configured to have a concavo-convex shape having a large number of projecting convex portions 81 at the front end portion, and therefore the pressure received from the metal separator 60 ( Load) can be distributed to each protrusion-like convex portion 81, and as a result, the change of the load with respect to the crushing margin S can be a gentle change compared to the conventional flat shoulder.

  Therefore, when the preferable load range to the shoulder portion is Fa ≦ F ≦ Fb, the range of the crushing margin S that achieves the preferable load range is W2 in the case of the shoulder portion having a flat tip portion. On the other hand, in the case of the shoulder portions 45b and 45c in the present embodiment in which the tip portion is configured to have an uneven shape, the width is set to W1, which is wider than W2.

  Accordingly, the seal structure 45 in the gasket member 40 of the present embodiment is easier to control the load even if the width of the shoulder portions 45b and 45c is wider than that of the shoulder portion having a flat front end portion. Since the width of the shoulder portions 45b and 45c can be given to the shoulder portions 45b and 45c, the sealing performance can be suitably ensured even during lateral displacement. Become.

  In addition, since the tips of the shoulders 45b and 45c, that is, the contact surfaces with the metal separator 60 are configured to be uneven, the static friction coefficient μ of the contact surfaces increases, and as a result, the metal separator 60 and The frictional force increases. Therefore, the gasket member 40 according to the present embodiment is less likely to cause a lateral shift as compared with a conventional gasket member having a shoulder portion having a flat tip portion. Therefore, even if the load received by the gasket member 40 is reduced, the lateral displacement of the gasket member 40 can be suitably suppressed.

  The description will be continued from FIG. 2 to FIG. 4 again. The air electrode gasket 41 in the gasket member 40 is formed with an open recess 46 on the opposite two end sides 46a, 46b side. The concave portion 46 accommodates the air electrode side collector 63 (see FIG. 6A) when the metal separator 60 is laminated, and the air as the oxidant gas flows on the air electrode 22 in the direction of the arrow X (or the opposite direction). ) Is formed.

  On the other hand, a seal structure 51 is formed on the outer periphery of the fuel electrode gasket 42 in the gasket member 40. The seal structure 51 prevents fuel gas from leaking from the fuel cell stack 100 (or unit cell 10) to the outside.

  Similar to the seal structure 45 described above, the seal structure 51 includes a seal lip portion 51a and shoulder portions located on both sides of the seal lip portion 51a in cross-sectional view (that is, the inner peripheral side and the outer peripheral side of the seal lip 45a). 51b, 51c, a groove 51d formed between the seal lip 51a and the shoulder 51b, and a groove 51e formed between the seal lip 51a and the shoulder 51c.

  Similar to the seal lip 45a, the seal lip portion 51a is deformed by being pressed from the metal separator 60 facing when the fuel cell stack 100 is configured (stacked), and has a gas seal function by being in close contact with the metal separator 60. It is a part to be exhibited, and has a sharp tapered tip, and is configured such that its height is higher than the height of the shoulders 51b and 51c.

  The shoulder portions 51b and 51c together with the above-described shoulder portions 45b and 45c are portions that define the distance between the pair of metal separators 60, and the height thereof is lower than the height of the seal lip portion 51a, and is substantially the same height as each other. It is configured to be. Further, the shoulder portions 51b and 51c are formed in a concavo-convex shape having a wide tip portion and a large number of projecting convex portions 81, similarly to the shoulder portions 45b and 45c (see FIG. 4B). .

  Therefore, the seal structure 51 having the shoulder portions 51b and 51c having a concavo-convex shape in which the front end portion has a large number of protruding convex portions 81 has the same effect as the seal structure 45 described above. That is, since the static friction coefficient μ of the contact surface with the metal separator 60 is increased, it is possible to make it difficult to cause lateral displacement and to easily control the load, so that the width as a shoulder portion can be sufficiently exhibited. Can be provided to the shoulder portions 51b and 51c, and it is possible to suitably ensure the sealing performance even in the case of lateral displacement.

  Moreover, the groove parts 51d and 51e are parts which function as escape parts of the insulating elastic body for allowing deformation of the seal lip part 51a due to a compressive load, like the groove parts 45d and 45e described above.

  A recess 52 is formed in the fuel electrode gasket 42 of the gasket member 40. The recess 52 accommodates the fuel electrode side collector 62 (see FIG. 6B) when the metal separators 60 are stacked, and the fuel gas (for example, hydrogen) moves on the fuel electrode 23 in the arrow Y direction (or vice versa). A fuel chamber that circulates in the direction) is formed.

  Next, the metal separator 60 of the present embodiment will be described with reference to FIG. 6A is a perspective view schematically showing one surface side of the metal separator 60, and FIG. 6B is a perspective view schematically showing the back surface side of the metal separator 60 shown in FIG. 6A. FIG. 6C is a cross-sectional view taken along line VIc-VIc in FIG.

  The metal separator 60 includes a plate-shaped separator main body 61, a fuel electrode side collector 62 provided on one surface of the separator 61, and an air electrode side collector 63 provided on the other surface of the separator 61.

  The separator body 61 functions as a gas blocking member between the adjacent unit cells 10 and is made of a conductive thin plate, and corresponds to the openings 43 and 44 of the gasket member 40 (that is, when stacked). Openings 61a and 61b serving as fuel gas flow paths are opened at positions communicating with the openings 43 and 44). As the conductive thin plate constituting the separator main body 61, for example, a thin plate obtained by subjecting a stainless steel, nickel alloy, titanium alloy or the like to a corrosion-resistant conductive treatment such as gold plating can be used.

  The fuel electrode side collector 62 is a current collector that is accommodated in the recess 52a (see FIG. 2) of the gasket member 40 and collects current generated by electrode reaction by contacting the fuel electrode 23 side of the membrane electrode assembly 20. is there.

  The fuel electrode side collector 62 is erected at the same height from one surface side of the separator body 61, and has a plurality of conductive ribs 62a extending between the opening 61a and the opening 61b, and these ribs 62a. And a current collecting member 62b which is a conductive plate material (for example, a metal plate material such as an expanded metal or a punching metal) having a large number of openings disposed at the front end thereof. A space 62c surrounded by the rib 62a adjacent to the separator body 61 and the current collecting member 62a functions as a fuel gas flow path.

  On the other hand, the air electrode side collector 63 is housed in the recess 46 (see FIG. 2) of the gasket member 40 and contacts the air electrode 22 side of the membrane electrode assembly 20 to collect current generated by the electrode reaction. It is an electric body.

  The air electrode side collector 63 is erected at the same height from the other surface side of the separator body 61, and has a plurality of conductive ribs 63a extending in a direction substantially perpendicular to the ribs 62a, and tips of these ribs 63a. And a current collecting member 63b, which is a conductive plate material (for example, a metal plate material such as expanded metal or punching metal) having a large number of openings. A space 63c surrounded by the rib 63a adjacent to the separator body 61 and the current collecting member 63b functions as an air flow path. Since the air electrode side collector 63 has a current collecting member 63b having a large number of openings, water generated in the air electrode 22 as a result of the electrode reaction is transmitted to the space 63c (air channel). Can do.

  As the rib 62a and the current collecting member 62b constituting the fuel electrode side collector 62 and the rib 63a and the current collecting member 63b constituting the air side collector 63, the material adopted as the separator main body 61, that is, stainless steel is used. Steel, nickel alloy, titanium alloy or the like subjected to a corrosion-resistant conductive treatment such as gold plating can be used.

  As described above, according to the first embodiment, the tip portions of the shoulder portions 45b, 45c, 51b, 51c in the gasket member 40, that is, the portion that becomes the contact surface with the metal separator 60 is formed with a large number of protrusions. By forming the concavo-convex shape having the convex portions 81, the lateral displacement is prevented by increasing the static friction coefficient μ, and the load control of the shoulder portion is widened by distributing the load to the respective protruding convex portions 81. Is also easier. As a result, the load applied to the seal structures 45 and 51 can be reduced while avoiding the adverse effects due to the lateral displacement.

  Next, a second embodiment of the present invention will be described with reference to FIG. Fig.7 (a) is an expanded sectional view which shows typically the sealing structures 45 and 51 of 2nd Embodiment in this invention, FIG.7 (b) is A section in Fig.7 (a), ie, FIG. It is an enlarged view of the front-end | tip part of the shoulder parts 45c and 51c. FIG. 7B is an enlarged view of the tip portions of the shoulder portions 45c and 51c, but the tip portions of the shoulder portions 45b and 51b have the same shape.

  Whereas the shoulder portions 45b, 45c, 51b, 51c of the seal structure bodies 45, 51 of the first embodiment described above are configured in a concavo-convex shape having a large number of projecting convex portions 81 at the wide tip portion, In 2nd Embodiment, as shown in FIG.7 (b), it is comprised in the uneven | corrugated shape which has many recessed parts 82 recessedly provided in the wide front-end | tip part of shoulder part 45b, 51b (shoulder part 45c, 51c is also the same). Has been.

  These recesses 82 are formed as a suction cup structure (adsorption structure) that functions as a suction cup. That is, when the seal structures 45 and 51 are pressed by the metal separator 60, the recess 82 adsorbs the metal separator 60 by the negative pressure generated inside.

  Therefore, according to the seal structures 45 and 51 of the second embodiment, in addition to the increase in the static friction coefficient μ due to the concavo-convex shape of the tip portion, by the adsorption effect by the concave portion 82 provided as a suction cup structure, The occurrence of lateral shift can be effectively suppressed.

  Moreover, since the recessed part 82 which is a suction cup structure can adsorb | suck the metal separator 60, it can hold | maintain in the state which positioned the gasket member 40 and the metal separator 60, and can suppress the position shift at the time of a lamination process.

  As described above, the present invention has been described based on the embodiments, but the present invention is not limited to the above-described embodiments, and various improvements and modifications can be easily made without departing from the spirit of the present invention. It can be guessed.

  For example, in each of the above embodiments, the shoulder portions 45b and 45c are provided on both the outer peripheral side and the inner peripheral side of the seal lip portion 45a, and the shoulder portions 51b and 51c are provided on both the outer peripheral side and the inner peripheral side of the seal lip portion 51a. However, the shoulder portion may be provided only on either the outer peripheral side or the inner peripheral side of the seal lip portion.

  Moreover, in the said 1st Embodiment, the uneven | corrugated shape formed in the front-end | tip part of shoulder part 45b, 45c, 51b, 51c is made into the uneven | corrugated shape which has many protrusion-shaped convex parts 81, In the said 2nd Embodiment, a shoulder Although the concavo-convex shape formed at the tip portions of the portions 45b, 45c, 51b, 51c is a concavo-convex shape having a large number of concave portions 82, a groove-like concavo-convex shape may be formed at the tip portion of the shoulder portion. In this case, the direction in which the groove extends may be any of the longitudinal direction of the shoulder portion, the short side direction (width direction), and the oblique direction, and the groove extends in a curved shape even if it extends linearly in a top view. Alternatively, it may extend in a wave shape.

1 is an exploded perspective view showing a part of a fuel cell stack in which a plurality of unit cells of a fuel cell are stacked. (A) is a perspective view which shows typically the one surface side of the gasket member by which the membrane electrode assembly is integrated by the inner peripheral side, (b) is the back surface of the gasket member shown to Fig.2 (a). It is a perspective view which shows the side typically, (c) is sectional drawing in the IIc-IIc line | wire of Fig.2 (a). (A) is the front view of the part seen from the arrow IIIa direction in Fig.2 (a), (b) is sectional drawing in the IIIb-IIIb line | wire of Fig.3 (a), (c) is It is the front view of the part seen from the arrow IIIc direction in Fig.2 (a). (A) is an expanded sectional view showing typically the seal structure of a 1st embodiment, and (b) is an enlarged view of the A section in Drawing 4 (a). (A) is a graph which shows the relationship between the crush margin S of the shoulder part which comprised the front-end | tip part in uneven | corrugated shape in 1st Embodiment, and the load F concerning this shoulder part whose width | variety is T, (b) These are the graphs which show the relationship between the crushing margin S of the shoulder part of the conventional gasket member used as a comparative example, and the load F applied to the shoulder part having a width of T. (A) is a perspective view which shows typically the one surface side of a metal separator, (b) is a perspective view which shows typically the back surface side of the metal separator shown to Fig.6 (a), (c) These are sectional drawings in the VIc-VIc line of Drawing 6 (a). (A) is an expanded sectional view which shows typically the sealing structure of 2nd Embodiment, (b) is an enlarged view of the front-end | tip part of A part in Fig.7 (a).

Explanation of symbols

10 unit cell 20 membrane electrode assembly 21 solid polymer electrolyte membrane 22 air electrode (part of a pair of electrode layers)
23 Fuel electrode (part of a pair of electrode layers)
40 Gasket member 45a Seal lip (seal lip)
45b shoulder 45c shoulder 51a seal lip (seal lip)
51b shoulder 51c shoulder 60 metal separator (separator)
81 Protruding convex part (part of irregular shape)
82 Concavity (part of uneven shape, adsorption structure)
100 Fuel cell stack

Claims (3)

A membrane electrode assembly having a solid polymer electrolyte membrane and a pair of electrode layers laminated on both sides of the solid polymer electrolyte membrane, and a gas flow provided to each electrode layer provided on both sides of the membrane electrode assembly A gasket member that is used in a fuel cell including a pair of separators having a path and is disposed between the membrane electrode assembly and the pair of separators to ensure gas sealing properties,
A shoulder portion made of an elastic body that contacts the separator and receives pressure from the separator,
A gasket member, wherein a contact surface of the shoulder portion with the separator is formed in an uneven shape.   2. The gasket member according to claim 1, wherein the uneven shape is a suction structure recessed in a contact surface of the shoulder portion with the separator. A membrane electrode assembly having a solid polymer electrolyte membrane and a pair of electrode layers laminated on both sides of the solid polymer electrolyte membrane, and a gas flow supplied to each electrode layer provided on both sides of the membrane electrode assembly A plurality of fuel cell unit cells each including a pair of separators having a path, and the gasket member according to claim 1 or 2 disposed between the membrane electrode assembly and the pair of separators. A fuel cell stack, characterized by comprising.

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