JP6544229B2 - Fuel cell - Google Patents

Description

  The present invention relates to a fuel cell.

  In general, a fuel cell has a stack structure in which a plurality of fuel cells are stacked. Each fuel cell has a membrane electrode gas diffusion layer assembly in which gas diffusion layers are disposed on both sides of a membrane electrode assembly, and two separators sandwiching the membrane electrode gas diffusion layer assembly. In this fuel cell, the peripheral portion of the membrane electrode gas diffusion layer assembly between the two separators is sealed by a sealing member such as rubber or resin. Specifically, in Patent Document 1, the size of the gas diffusion layer disposed on one side of the membrane electrode assembly is made smaller than the size of the gas diffusion layer disposed on the other side of the membrane electrode assembly. There is disclosed a configuration in which a plate-like seal member is disposed on the outer periphery of the small gas diffusion layer, and the seal member is adhered by an adhesive.

JP, 2013-251253, A

  In the prior art, since the plate-like seal member and the gas diffusion layer are separate members, a gap is inevitably generated between them. When the electrolyte membrane shrinks or swells at the time of power generation or the like, the electrolyte membrane may be deformed toward the gap and the electrolyte membrane may be broken. For this reason, in the structure which a clearance gap produces between a sealing member and a gas diffusion layer, the technique which can suppress a deformation | transformation of an electrolyte membrane was desired.

The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as the following modes.
The first aspect of the present invention is
A fuel cell,
A membrane electrode assembly,
A first gas diffusion layer disposed on the side of the first surface of the membrane electrode assembly;
A second gas diffusion layer disposed on the side of the second surface opposite to the first surface of the membrane electrode assembly;
A plate-like seal member provided on the outer periphery of the first surface of the membrane electrode assembly, wherein the plate-like seal member is disposed with a gap from the outer peripheral end of the first gas diffusion layer;
An adhesive for bonding the plate-like seal member, which extends from between the first gas diffusion layer and the membrane electrode assembly through the gap between the plate-like seal member and the membrane electrode assembly With an adhesive placed in the range,
Equipped with
The adhesive is
The portion corresponding to the gap is inclined in a direction from the first surface to the second surface as it is separated from the outer peripheral end of the first gas diffusion layer,
The membrane electrode assembly is
The portion corresponding to the gap is not separated from the adhesive, and is directed from the first surface to the second surface together with the adhesive as it is separated from the outer peripheral end of the first gas diffusion layer Inclined to
The portion corresponding to the plate-like seal member is more depressed in the direction from the first surface to the second surface than the portion corresponding to the gap.
It is a fuel cell.
Furthermore, the present invention can also be realized as the following modes.

(1) One embodiment of the present invention is a fuel cell. This fuel cell comprises a membrane electrode assembly, a first gas diffusion layer disposed on the side of the first surface of the membrane electrode assembly, and an opposite to the first surface of the membrane electrode assembly. A second gas diffusion layer disposed on the side of the second surface, and a plate-like seal member provided on an outer periphery of the first surface of the membrane electrode assembly, the first gas diffusion layer A plate-like seal member arranged with a gap from the outer peripheral end of the layer, and an adhesive for bonding the plate-like seal member, wherein the adhesive is used from between the first gas diffusion layer and the membrane electrode assembly An adhesive disposed in a range extending between the plate-like seal member and the membrane electrode assembly through a gap. The adhesive is inclined in a direction from the first surface to the second surface as it is separated from the outer peripheral end of the first gas diffusion layer in a portion corresponding to the gap.

  According to the fuel cell of this aspect, both sides of the adhesive bonding the plate-like seal member are between the first gas diffusion layer and the membrane electrode assembly, and between the plate-like seal member and the membrane electrode assembly. The portion that corresponds to the gap between the membrane electrode assembly and the plate-like seal member, which is constrained by the gap between the membrane electrode assembly and the plate-like seal member, inclines from the first surface to the second surface of the membrane electrode assembly . In the inclined portion of the adhesive, as a result of being pulled by bending the adhesive, stress against displacement in the Y direction is increased. An increase in stress against displacement in the Y direction means that the strength of the adhesive is increased in the Y direction. For this reason, according to the fuel cell of this aspect, when the electrolyte membrane at the time of power generation etc. shrinks or swells, it is possible to suppress deformation of the electrolyte membrane around the above-mentioned gap.

It is principal part sectional drawing of the fuel cell as one Embodiment of this invention. It is an explanatory view showing the first half of the manufacturing method of a fuel cell. It is an explanatory view showing the second half of the manufacturing method of a fuel cell. It is principal part sectional drawing of the fuel cell as a reference example.

A. Fuel cell configuration:
FIG. 1 is a sectional view of an essential part of a fuel cell 100 according to an embodiment of the present invention. As illustrated, the fuel cell 100 includes a membrane electrode gas diffusion layer assembly 10, a pair of separators 50 and 60 sandwiching the membrane electrode gas diffusion layer assembly 10, and a membrane electrode gas between the separators 50 and 60. And a plate-like seal member 80 bonded to the peripheral edge portion of the diffusion layer assembly 10.

  A membrane electrode gas diffusion layer assembly (MEGA) 10 includes a membrane electrode assembly (MEA) 20 and a pair of gas diffusion layers 30 and 40 disposed on both sides of the MEA 20. And.

  The MEA 20 is formed by bonding catalyst electrode layers (a cathode 22 and an anode 23) on both sides of the electrolyte membrane 21. As the electrolyte membrane 21, a membrane formed of a solid polymer material such as a fluorine-based resin, for example, Nafion (registered trademark) can be used. As the cathode 22 and the anode 23, a catalyst layer in which a catalyst such as platinum is supported on carbon particles can be used. In the present embodiment, the size of the cathode 22 in the planar direction is smaller than the size of the anode 23 in the planar direction.

  The diffusion layer 30 disposed on the surface (first surface) of the cathode 22 of the pair of gas diffusion layers 30 and 40 is hereinafter referred to as the cathode side gas diffusion layer 30. Hereinafter, the diffusion layer 40 disposed on the surface (second surface) of the anode 23 of the pair of gas diffusion layers 30 and 40 will be referred to as an anode-side gas diffusion layer 40. Carbon cloth is used as the cathode side gas diffusion layer 30 and the anode side gas diffusion layer 40. As the cathode side gas diffusion layer 30 and the anode side gas diffusion layer 40, other members having conductivity and gas permeability such as carbon paper may be used. The cathode side gas diffusion layer 30 corresponds to the “first gas diffusion layer” in the embodiment of the present invention described in the section of [Summary of the Invention]. The anode-side gas diffusion layer 40 corresponds to the “second gas diffusion layer” in one embodiment of the present invention described in the section of [Summary of the Invention].

  Hereinafter, the direction on the cathode side gas diffusion layer 30 side in the stacking direction Y of the cathode side gas diffusion layer 30, the MEA 20, and the anode side gas diffusion layer 40 is referred to as "+ Y direction". Hereinafter, the direction on the anode side gas diffusion layer 40 side in the stacking direction is referred to as “−Y direction”.

  The cathode gas diffusion layer 30 is bonded to a region inside the region to which the anode gas diffusion layer 40 is bonded in a plan view as viewed in the stacking direction Y. That is, the MEA 20 is bonded to the entire surfaces of the cathode side gas diffusion layer 30 and the anode side gas diffusion layer 40, and on the + Y side surface of the MEA 20 from the region where the cathode side gas diffusion layer 30 is bonded Is exposed. A plate-like seal member 80 is disposed on the outer periphery of this exposed portion of the MEA 20. As used herein, “periphery” means a range that includes not only the outermost end, but also, to a certain extent, the portion that goes inward. Further, the plate-like seal member 80 is disposed with a gap S open from the outer peripheral end 30T of the cathode side gas diffusion layer 30.

  The separator 50 is laminated on the surface of the cathode side gas diffusion layer 30 in the MEGA 10. The size in the planar direction of the separator 50 is larger than the size in the planar direction of the cathode side gas diffusion layer 30. For this reason, in a plan view as viewed from the stacking direction Y, the separator 50 is configured to protrude outside the cathode side gas diffusion layer 30. In the separator 50 (hereinafter also referred to as “the cathode side separator 50”), the air as the oxidant gas is formed along the surface of the cathode side gas diffusion layer 30 on the contact surface with the cathode side gas diffusion layer 30 in the MEGA 10 An oxidant gas channel 52 is formed to flow the oxygen. The other separator 60 is laminated on the surface of the anode gas diffusion layer 40 in the MEGA 10. In this separator 60 (hereinafter also referred to as “anode side separator 60”), hydrogen as fuel gas is made along the surface of the anode gas diffusion layer 40 on the contact surface of the MEGA 10 with the anode gas diffusion layer 40. A fuel gas channel 62 for flowing is formed. In the present embodiment, a metal plate is used as the separators 50 and 60. As the separators 50 and 60, another member which is gas impermeable and has conductivity may be used.

  The plate-like seal member 80 is a plate-like frame having a large hole inside. The plate-like seal member 80 is bonded between the surface on the + Y direction side of the outer periphery of the MEA 20 and the cathode side separator 50, and seals between the separators 50 and 60. For example, a resin such as PE, PP, PET, or PEN can be used as the plate-like sealing member 80. The adhesion of the plate-like seal member 80 is made by an adhesive 82 applied in a range from between the cathode side gas diffusion layer 30 and the MEA 20 to near the outer peripheral end (not shown) of the MEA 20. As the adhesive 82, EPDM, epoxy, PIB or the like can be used.

  In the present embodiment, as described above, since the size in the plane direction of the cathode 22 is smaller than the size in the plane direction of the anode 23, the outer periphery of the surface on the + Y direction side of the MEA 20 does not have the cathode 22. The film 21 is exposed. A portion of the adhesive 82 is applied to the exposed portion. The exposed portion of the electrolyte membrane 21 is also a part of the MEA 20.

  The outer peripheral portion of the MEA 20 to which the plate-like seal member 80 is bonded is depressed in the −Y direction as compared with the vicinity of the center of the MEA 20. The application range of the adhesive 82 includes a portion 82A between the cathode side gas diffusion layer 30 and the MEA 20, a portion 82B corresponding to the gap S between the cathode side gas diffusion layer 30 and the plate-like seal member 80, and a cathode side gas Assuming division into the portion 82C between the diffusion layer 30 and the MEA 20, the outer peripheral edge 30T of the cathode side gas diffusion layer 30 for the portion 82B due to the depression of the outer peripheral portion (corresponding to the portion 82A) of the MEA 20 described above. As you move away from (from the right to the left in the figure), it is inclined in the -Y direction.

B. Fuel cell manufacturing method:
2 and 3 are explanatory views showing a method of manufacturing the fuel cell 100. FIG. As shown in FIGS. 2 and 3, the method of manufacturing the fuel cell 100 includes six steps from step 1 to step 6. Steps 1 to 6 are performed in this order. Each process 1 to 6 will be described in order.

[Step 1]
Step 1 shown in FIG. 2 is a preparation step. The cathode 22 and the anode 23 are attached to both sides of the electrolyte membrane 21, and a laminate in which the anode side gas diffusion layer 40 is joined to the anode 23 side is prepared.

[Step 2]
Step 2 is a punching step. The laminate prepared in step 1 is punched in the direction of arrow PR.

[Step 3]
Step 3 is an adhesive application step. An adhesive 82 is applied to the laminate obtained in step 2. Specifically, the adhesive 82 is applied to the outer periphery of the cathode 22 of the laminate obtained in Step 2. That is, the adhesive 82 is applied to the outer peripheral portion from the peripheral end surface 22T of the cathode 22 to the position inside the predetermined size u.

[Step 4]
Step 4 shown in FIG. 3 is a plate-like sealing member bonding step. The plate-like seal member 80 is adhered to the laminate obtained in step 3. Specifically, the plate-like seal member is positioned such that the inner end face 80T of the plate-like seal member 80 is positioned outside the peripheral end face 22T of the cathode 22 in the application range of the adhesive 82 when viewed in the stacking direction Y. 80 is glued.

[Step 5]
Process 5 is a gas diffusion layer bonding process. The cathode side gas diffusion layer 30 is bonded to the laminate obtained in Step 4. Specifically, the cathode side gas diffusion layer 30 is joined so as to enter the cathode side gas diffusion layer 30 in the inner hole of the plate-like seal member 80. At this time, a gap v is formed between the inner end surface 80T, which is the wall surface of the hole of the plate-like seal member 80, and the outer peripheral end 30T of the cathode side gas diffusion layer 30.

[Step 6]
Process 6 is a cellification process. The laminate obtained in step 5 is sandwiched between a pair of separators 50 and 60 and pressed. By pressing, the outer peripheral portions of the MEA 20 and the anode gas diffusion layer 40 are bent by the cathode side separator 50, and the above-described characteristic shape of the adhesive 82 (the shape in which the portion 82B is inclined, FIG. The fuel cell 100 is manufactured.

C. Embodiment effect:
In the fuel cell 100 of the present embodiment configured as described above, both ends of the adhesive 82 are restrained by the space between the cathode side gas diffusion layer 30 and the MEA 20 and between the plate-like seal member 80 and the MEA 20. The portion 82B (FIG. 1) corresponding to the gap S between the MEA 20 and the plate-like seal member 80, which is between the two ends, is inclined in the -Y direction. In the inclined portion of the adhesive 82, as a result of being pulled by the bending of the adhesive 82, stress against displacement in the Y direction is increased. An increase in stress against displacement in the Y direction means that the strength of the adhesive 82 is increased in the Y direction. In particular, in the present embodiment, since the inclined portion of the adhesive 82 is created by applying a load at the time of cellization, the adhesive 82 is subjected to bending stress, and the effect thereof is particularly large. For this reason, according to the fuel cell 100, it is possible to suppress deformation of the electrolyte membrane 21 around the gap S when the electrolyte membrane shrinks or swells during power generation or the like.

  FIG. 4 is a cross-sectional view of main parts of a fuel cell 900 as a reference example. In the reference example, each component is denoted by reference numeral 900. In the fuel cell 900, the components whose lower two digits of each symbol are the same as those of the first embodiment have the same functions as the components of the first embodiment. In the fuel cell 900, the outer peripheral portion of the MEA 920 is not depressed in the -Y direction as compared with the fuel cell 100 of the first embodiment, and the gap SS between the cathode side gas diffusion layer 930 and the plate-like seal member 980 For the adhesive portion 982B corresponding to Y, the plane direction perpendicular to the stacking direction Y is taken.

  In the fuel cell 900 of this reference example, when the electrolyte membrane 911 shrinks or swells during power generation or the like, the electrolyte membrane 911 may be deformed toward the gap SS as shown by the broken line in the figure, and may be broken. there were. On the other hand, in the fuel cell unit 100 according to the embodiment, as described above, since the deformation of the electrolyte membrane 921 around the gap S can be suppressed, the breakage of the electrolyte membrane can be prevented.

  The present invention is not limited to the above-described embodiment, and can be realized in various configurations without departing from the scope of the invention. For example, the technical features in the embodiments corresponding to the technical features in each of the modes described in the section of the summary of the invention can be used to solve some or all of the problems described above, or one of the effects described above. It is possible to replace or combine as appropriate to achieve part or all. Moreover, elements other than the element described in the independent claim in the component in each embodiment mentioned above are additional elements, and can be omitted suitably.

DESCRIPTION OF SYMBOLS 10 ... Membrane electrode gas diffusion layer assembly 21 ... Electrolyte film 22 ... Cathode 22 T ... Peripheral end face 23 ... Anode 30 ... Cathode side gas diffusion layer 30 T ... Outer peripheral end 40 ... Anode side gas diffusion layer 50 ... Cathode side separator 52 ... Oxidant Gas flow path 60: Anode side separator 62: Fuel gas flow path 80: Plate-like seal member 80T: Inner end face 82: Adhesive 82A to 82C: Part 100: Fuel cell 900: Fuel cell 911: Electrolyte membrane 982B: Bonding Agent part S ... Gap Y ... Stacking direction

Claims (1)

A fuel cell,
A membrane electrode assembly,
A first gas diffusion layer disposed on the side of the first surface of the membrane electrode assembly;
A second gas diffusion layer disposed on the side of the second surface opposite to the first surface of the membrane electrode assembly;
A plate-like seal member provided on the outer periphery of the first surface of the membrane electrode assembly, wherein the plate-like seal member is disposed with a gap from the outer peripheral end of the first gas diffusion layer;
An adhesive for bonding the plate-like seal member, which extends from between the first gas diffusion layer and the membrane electrode assembly through the gap between the plate-like seal member and the membrane electrode assembly With an adhesive placed in the range,
Equipped with
The adhesive is
The portion corresponding to the gap is inclined in a direction from the first surface to the second surface as it is separated from the outer peripheral end of the first gas diffusion layer ,
The membrane electrode assembly is
The portion corresponding to the gap is not separated from the adhesive, and is directed from the first surface to the second surface together with the adhesive as it is separated from the outer peripheral end of the first gas diffusion layer Inclined to
The portion corresponding to the plate-like seal member is more depressed in the direction from the first surface to the second surface than the portion corresponding to the gap.
Fuel cell.

Images