JP2014120226A - Fuel battery cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components of a fuel battery cell and enhance productivity.SOLUTION: In a fuel battery cell in which one resin frame 40 is interposed between a first separator 20 and a second separator, an adhesive agent is arranged between a first surface part 42 and a second surface part 44 of the resin frame 40, and the spaces between the first, second separators 20, 30 and the resin frame 40 are respectively jointed with the adhesive agent, the resin frame 40 includes: a first recess 42a provided on the first surface part 42 and including the adhesive agent therein; a second recess 44a provided on the second surface part 44 and including the adhesive agent therein; and a slope part 48 positioned on a circumference 46 between the first surface part 42 and the second surface part 44 and expanding toward the second surface part 44 side. Also, the fuel battery cell has positional relationship in which at least a part of a range b opposing the second separator in a flat part of a flange forming the second recess overlaps the entire range opposing the first separator in a flat part of the flange forming the first recess 42a in a surface direction.

Description

  The present invention relates to a fuel battery cell.

  A fuel cell that is a power generation unit of a fuel cell has a structure in which a membrane electrode assembly in which an electrolyte membrane is sandwiched between two electrodes and a separator having a reaction gas flow path are integrally formed. A resin frame is interposed between the membrane electrode assembly and the separator so that the reaction gas does not leak from the peripheral edge of the electrolyte membrane. Patent Document 1 describes a configuration in which a membrane electrode assembly is supported by two resin frames and the two resin frames are sandwiched between a pair of separators.

JP 2006-19204 A

  However, in the technique described in Patent Document 1, since two resin frames are used, there is a problem that the number of parts is large and productivity is lowered. In addition, improvement in power generation efficiency as a fuel cell, cost reduction, size reduction, and resource saving have been desired.

  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.

  According to one aspect of the present invention, a fuel battery cell is provided. The fuel battery cell is bonded to a first surface portion of the resin frame and a second surface portion at a position corresponding to the first surface portion with a resin frame interposed between the first separator and the second separator. By disposing an agent, the first separator and the resin frame are bonded and the second separator and the resin frame are bonded to each other. The resin frame is provided on the first surface portion and includes a first recess for containing the adhesive; and a second recess provided on the second surface portion for containing the adhesive; and the first And a slope portion that is located at a peripheral edge between the surface portion and the second surface portion and extends toward the second surface portion. Further, at least a range of the flat portion of the flange that forms the second concave portion that faces the second separator in the flat portion of the flange that forms the first concave portion of the flat portion of the flange that forms the second concave portion. Some are in a positional relationship overlapping in the surface direction.

  Here, the “surface direction” is a direction that coincides with the surface direction of the first surface portion and the second surface portion of the resin frame. The term “overlap” means a state where they are completely overlapped, and does not include a case where only a part overlaps. According to the fuel battery cell of this embodiment, when the adhesive overflows in the first recess, the adhesive can be held by the slope portion. For this reason, an adhesive can always be interposed in the flat portion of the flange forming the first recess. Conventionally, when the number of resin frames is one, the positions of the frames in the stacking direction are random, and the adhesive may not be interposed between the flat portion of the flange of the resin frame and the separator. On the other hand, in the embodiment of the present invention, as described above, since the adhesive can always be interposed in the flat portion of the flange, one resin frame can be provided. Therefore, the number of parts can be reduced, and cost reduction and productivity improvement can be achieved.

  The present invention can be realized in various forms. For example, it is realizable with a fuel cell stack provided with the fuel cell of the above-mentioned form, a vehicle carrying this fuel cell stack, and the like.

It is a principal part end elevation of the fuel cell stack as one embodiment of the present invention. It is explanatory drawing which shows the outer peripheral part of a resin frame, and its circumference | surroundings. It is explanatory drawing which compares and shows the case where the distance between a separator and a resin frame becomes the maximum, and the case where the distance becomes the minimum. It is explanatory drawing which shows a comparative example. It is explanatory drawing which shows the outer peripheral part of the resin frame in the fuel cell of 2nd Embodiment, and its circumference | surroundings. It is explanatory drawing which shows the outer peripheral part of the resin frame in the fuel cell of 3rd Embodiment, and its periphery.

Next, an embodiment of the present invention will be described.
1. First embodiment:
(1) Overall configuration:
FIG. 1 is an end view of a main part of a fuel cell stack as one embodiment of the present invention. As illustrated, the fuel cell stack 200 has a structure in which a plurality of fuel cells 100 are stacked. The fuel cell 100 is disposed outside the peripheral edge of the MEGA 10 between the membrane electrode gas diffusion layer assembly (hereinafter referred to as “MEGA”) 10, the separators 20 and 30 that sandwich the MEGA 10, and the separators 20 and 30. And a resin frame 40. MEGA is an abbreviation for “Membrane Electrode Gas diffusion layer Assembly”. In the following description, the stacking direction of the fuel cells 100 (up and down direction in FIG. 1) is referred to as the Y direction, and the direction perpendicular to the stacking direction, that is, the surface direction of the fuel cells 100 (left and right direction in FIG. 1). Called the X direction.

  The MEGA 10 includes an electrolyte membrane (electrolyte layer) 12, and a catalyst electrode layer (anode) 14 and a gas diffusion layer 15 are formed in this order on one surface of the electrolyte membrane 12. On the other surface, a catalyst electrode layer (cathode) 16 and a gas diffusion layer 17 are formed in this order. As the electrolyte membrane 12, a membrane formed of a solid polymer material such as a fluorine resin, for example, Nafion (registered trademark) can be used. As the catalyst electrode layers 14 and 16, a catalyst layer in which a catalyst such as platinum is supported on carbon particles can be used. The gas diffusion layers 15 and 17 are made of a material having gas permeability and conductivity such as carbon cloth or carbon paper.

  The separator 20 is laminated on the surface of the anode side gas diffusion layer 15 in the MEGA 10. In the separator 20, a fuel gas flow path 22 for flowing hydrogen as a fuel gas is formed along the surface of the anode side gas diffusion layer 15 on the contact surface of the MEGA 10 with the anode side gas diffusion layer 15. ing. The separator 30 is laminated on the surface of the cathode side gas diffusion layer 17 in the MEGA 10. In the separator 30, an oxidant gas flow path for flowing air as an oxidant gas along the surface of the cathode side gas diffusion layer 17 on the contact surface of the MEGA 10 with the cathode side gas diffusion layer 17 (see FIG. (Not shown) is formed. In the present embodiment, metal plates are used as the separators 20 and 30. As the separators 20 and 30, other members having gas impermeability and conductivity may be used. A gasket 60 is formed on the surface of the separator 30 opposite to the resin frame 40.

  The resin frame 40 has a plate shape and is disposed between the separator 20 and the separator 30. A central portion in the X direction of the resin frame 40 is hollowed out, and the MEGA 10 is disposed in the hollowed portion. That is, the resin frame 40 is provided on the outer peripheral portion of the MEGA 10 between the separator 20 and the separator 30. The MEGA 10 has a shape in which the electrolyte membrane 12 is exposed to the outside of the catalyst electrode layers 14 and 16 and the gas diffusion layers 15 and 17 in the X direction, and the resin frame 40 sandwiches the exposed portion of the electrolyte membrane 12. To do. The resin frame 40 is made of a thermosetting resin such as epoxy, nylon, or phenol, or a thermoplastic resin such as polypropylene or polyethylene.

  The resin frame 40 and the separators 20 and 30 are bonded to each other by an adhesive layer 52 disposed on the outer peripheral portion of the upper surface portion of the resin frame 40 and an adhesive layer 54 disposed on the outer peripheral portion of the lower surface portion of the resin frame 40. Is done. The configuration of the outer peripheral portion of the resin frame 40 is a characteristic portion of the present invention and will be described in detail later. As the adhesive layers 52 and 54, a thermoplastic adhesive resin imparted with adhesiveness, for example, a modified polyolefin such as polypropylene or polyethylene, which contains a silane coupling agent or a polar group such as carboxylic acid, or thermosetting Adhesive resin such as silicone, polyisobutylene, epoxy, urethane, and the like can be used.

  Further, holes 70 for constituting manifolds for fuel gas, oxidant gas, and cooling medium are provided in an inner portion of the resin frame 40 in the X direction from the adhesive layers 52 and 54. . The separators 20 and 30 are also provided with holes 24 and 34 at positions corresponding to the holes 70, and the holes 24 of the separator 20, the holes 70 of the resin frame 40, and the holes 34 of the separator 30, A manifold extending in the stacking direction of the fuel cell stack 200, that is, the X direction is configured. Fuel gas, oxidant gas, and cooling medium flowing through each manifold are distributed to each MEGA 10.

(2) Structure of characteristic part:
FIG. 2 is an explanatory view showing the outer peripheral portion of the resin frame 40 and its periphery. As shown in the drawing, an upper concave portion 42 a is formed on the outer peripheral portion of the upper surface portion 42 of the resin frame 40, and a lower concave portion 44 a is formed on the outer peripheral portion of the lower surface portion 44 of the resin frame 40. The adhesive layer 52 for adhering the separator 20 is disposed in a region including the upper concave portion 42a. The adhesive layer 54 for adhering the separator 30 is disposed in a region including the lower concave portion 44a. A peripheral edge portion 46 between the upper surface portion 42 and the lower surface portion 44 of the resin frame 40 constitutes an inclined surface that gradually expands toward the lower surface portion 44 side. Further, the wall surface 48 for forming the hole portion 70 as a manifold also forms an inclined surface that gradually expands toward the lower surface portion 44 side.

  In general, parts constituting industrial products have dimensional tolerances. For this reason, the distance between the upper separator 20 and the resin frame 40 varies depending on the dimensional error. FIG. 3 is an explanatory diagram showing a comparison between a case where the distance between the separator 20 and the resin frame 40 is maximum and a case where the distance is minimum. In the figure, the position of the separator 20X indicated by a broken line indicates the maximum case, and the position of the separator 20 indicated by a solid line indicates the minimum case. Assuming that the amount of adhesive applied to form the adhesive layer 52 is constant, the range of the adhesive layer 52 changes depending on the position of the separator 20 between the minimum case and the maximum case. In the present embodiment, in the maximum case, the cell cross section is designed so that the area BA surrounded by the broken line in the drawing is within the range of the adhesive layer 52. That is, in the maximum case, the adhesive overflows the upper concave portion 42a and stays in the range of the flat portions T1 and T2 of the flanges 42b and 42c forming the upper concave portion 42a. On the other hand, in the minimum case, the cell cross section is designed so that the adhesive layer 52 indicated by the solid line is obtained. That is, in the minimum case, the adhesive overflows the upper concave portion 42a, exceeds the flat portions T1 and T2 of the flanges 42b and 42c, travels along the inclined surfaces of the peripheral edge 46 and the wall surface 48, and within the range of the inclined surface. Try to stay.

  That is, in the fuel cell stack 200 of the present embodiment, the adhesive is in the range of the flat portions T1 and T2 of the flanges 42b and 42c even when the distance between the separator 20 and the resin frame 40 is maximum. Meet. On the other hand, even when the distance is minimum, the adhesive stays in the range of the wall surface 48 and does not protrude from the wall surface 48. Therefore, according to the fuel cell 100 provided in the fuel cell stack 200, the resin frame 40 and the separators 20 and 30 can be firmly bonded. Moreover, since it can prevent that the adhesive agent used for this adhesion sticks out from the planned range, the obstruction | occlusion of a flow path and the deterioration of workability | operativity can be prevented.

  Returning to FIG. 2, the outer flange 42b and the inner flange 42c that form the upper concave portion 42a of the resin frame 40 and the outer flange 44b and the inner flange 44c that form the lower concave portion 44a of the resin frame 40 are as follows. There is a positional relationship. First, the positional relationship between the flange 42b and the flange 44b on the outside will be described.

  As shown in FIG. 2, the entire flat portion T <b> 1 of the outer flange 42 b faces the separator 20. That is, in the X direction, the entire flat portion T1 of the outer flange 42b and a part of the separator 20 overlap. This overlapping portion is a range a in the figure. On the other hand, a part of the flat portion T3 of the outer flange 44b faces the separator 30. That is, in the X direction, a part of the flat portion T3 of the outer flange 44b and a part of the separator 30 overlap. This overlapping portion is a range b in the figure. In the X direction, the entire range a is in a positional relationship overlapping with at least a part of the range b. Here, “overlap” means a state in which they are completely overlapped, and does not include a case in which only a part overlaps.

  Note that, similarly to the positional relationship between the outer flange 42b and the flange 44b, the entire range facing the separator 20 in the flat portion T2 of the inner flange 42c is also provided between the inner flange 42c and the flange 44c. On the other hand, at least a part of the range facing the separator 30 in the flat portion T4 of the inner flange 44c is in a positional relationship overlapping in the X direction.

  A recess 26 is provided at a position facing the upper recess 42 a of the resin frame 40 in the separator 20. A gasket 60 provided in the fuel cell 100 adjacent to the upper side is interposed in the recess 26. Sealing performance is enhanced by the gasket 60.

  In the fuel cell 10 configured as described above, the upper surface portion 42 corresponds to the “first surface portion” described in the “Summary of the invention” column, and the lower surface portion 44 described in the “Summary of the invention” column. Corresponding to the “second surface portion”, the upper concave portion 42a corresponds to the “first concave portion” described in the “Summary of the invention” column, and the lower concave portion 44a corresponds to the “second outline” described in the “Summary of the invention” column. Corresponding to the “concave portion”, the peripheral edge 46 or the wall surface 48 corresponds to the “slope portion” described in the “Summary of Invention” column.

(3) Action and effect:
According to the fuel battery cell 100 of the present embodiment configured as described above, when the adhesive overflows in the upper concave portion 42a, the adhesive can be held by the peripheral edge portion 46 that is an inclined surface. For this reason, an adhesive can always be interposed in the flat portion T1 of the flange 42b that forms the upper concave portion 42a. Conventionally, when the number of resin frames is one, the positions of the frames in the stacking direction are random, and the adhesive may not be interposed between the flat portion of the flange of the resin frame and the separator. For this reason, conventionally, when a plurality of fuel cells are stacked, the separator is inclined, the fuel cells are deformed, and the gasket clearance becomes unstable and the sealing performance is lowered. On the other hand, in this embodiment, as described above, since the adhesive can always be interposed in the flat portion T1 of the flange 42b, when the fuel cells 100 are stacked, the flanges 42b of adjacent cells are connected to each other. Thus, the fastening load can be reliably transmitted, the cell deformation can be suppressed, and the gasket clearance can be made constant. As a result, one resin frame 40 can be provided. Therefore, the number of parts can be reduced, and cost reduction and productivity improvement can be achieved.

  Further, in the fuel cell 100 of the present embodiment, as described with reference to FIG. 2, the entire range a is in a positional relationship overlapping with at least a part of the range b in the X direction. There is an effect. FIG. 4 is an explanatory view showing a comparative example in which the shape of the resin frame is not preferable. In this comparative example, the entire range a does not overlap the range bx. For this reason, in the comparative example, a large load was applied in the shearing direction at the portion marked with a broken line in the figure, and there was a risk of frame cracking. On the other hand, in the present embodiment, the entire range a is in a positional relationship that overlaps at least a part of the range b, so that the large weight as described above is not applied. Therefore, the fuel battery cell 100 can prevent frame cracking.

2. Second embodiment:
FIG. 5 is an explanatory view showing an outer peripheral portion of the resin frame 1040 and its periphery in the fuel battery cell of the second embodiment. The fuel cell of the second embodiment is different from that of the first embodiment only in the outer peripheral portion of the resin frame 1040, and the remaining configuration is the same as that of the first embodiment. In this configuration, the entire range a2 is in a positional relationship overlapping the entire range b2. Therefore, the fuel cell of the second embodiment can reduce the number of parts and reduce the cost and improve the productivity, as well as the fuel cell 100 of the first embodiment. Can be prevented.

3. Third embodiment:
FIG. 6 is an explanatory view showing the outer peripheral portion of the resin frame 2040 and the periphery thereof in the fuel battery cell of the third embodiment. The fuel cell of the third embodiment is the same as that of the second embodiment except that the shape of the separator 2030 is different from that of the fuel cell of the second embodiment. The separator 2030 has a shape obtained by inverting the opposing separator 20 in the horizontal direction, and includes a lower concave portion 2036 at a portion where the gasket 60 is disposed. As with the fuel cells of the first and second embodiments, the fuel cell of the third embodiment having such a configuration can reduce the number of parts to reduce costs and improve productivity. Frame cracking can be prevented.

4). Variations:
The present invention is not limited to the above-described embodiments and modifications, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

  In each of the above-described embodiments and modifications, the polymer electrolyte fuel cell is used as the fuel cell, but various fuel cells such as a phosphoric acid fuel cell, a molten carbonate fuel cell, and a solid oxide fuel cell are used. The present invention may be applied.

  It should be noted that elements other than those described in the independent claims among the constituent elements in the above-described embodiment and each modification are additional elements and can be omitted as appropriate.

10 ... Membrane electrode gas diffusion layer assembly (MEGA)
DESCRIPTION OF SYMBOLS 12 ... Electrolyte membrane 14 ... Catalyst electrode layer 15 ... Gas diffusion layer 17 ... Gas diffusion layer 20 ... Separator 22 ... Fuel gas flow path 24 ... Hole part 26 ... Recessed part 30 ... Separator 34 ... Hole part 40 ... Resin frame 42 ... Upper surface part 42a ... Upper concave portion 42b ... Flange 42c ... Flange 44 ... Lower surface portion 44a ... Lower concave portion 44b ... Flange 44c ... Flange 46 ... Peripheral portion 48 ... Wall surface 52 ... Adhesive layer 54 ... Adhesive layer 60 ... Gasket 70 ... Hole 100 ... Fuel Battery cell 200 ... Fuel cell stack 1040 ... Resin frame 2030 ... Separator 2036 ... Lower recess 2040 ... Resin frame T1 ... Flat part T2 ... Flat part T3 ... Flat part T4 ... Flat part

Claims (1)

By placing one resin frame between the first separator and the second separator and disposing the adhesive on the first surface portion of the resin frame and the second surface portion at a position corresponding to the first surface portion, respectively. A fuel battery cell in which the first separator and the resin frame, and the second separator and the resin frame are bonded to each other;
The resin frame is
A first recess provided in the first surface portion for containing the adhesive;
A second recess provided in the second surface portion for allowing the adhesive to reside;
A sloped portion located on the periphery between the first surface portion and the second surface portion and extending toward the second surface portion;
At least a part of the range facing the second separator in the flat portion of the flange forming the second recess, with respect to the entire range facing the first separator in the flat portion of the flange forming the first recess. However, the fuel cell unit is in an overlapping positional relationship in the plane direction.

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