Sealing member, method for manufacturing power generating cell, and method for manufacturing fuel cell

Abstract

The present application provides a sealing member, a method for manufacturing a power generating cell, and a fuel cell, which suppresses a decrease in sealing performance over time. The sealing member is arranged between a cathode separator and an anode separator of a power generating cell in a fuel cell, and seals the cathode separator and the anode separator by bonding them together, and includes: a base material; and a bonding layer arranged on at least one surface of the base material, the bonding layer containing a plurality of air bubbles in a bonded state.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a fuel cell. BACKGROUND

[0002] Patent Document 1 discloses a thermoplastic resin porous body composed of independent bubbles expanded into an elastomer by heating, which is sandwiched between members and overlapped, and the thermoplastic resin porous body is expanded by heat treatment after the formation of the laminate to be tightly attached between the members to seal a fluid.

[0003] Patent Document 2 discloses a gasket in which a foamed rubber layer is provided on the surface of a metal plate when the gasket is integrated with the surface of a separator by an adhesive.

[0004] Patent Document 3 discloses a gasket in which a sponge layer of independent bubbles is adhered to at least one surface of a separator by an adhesive layer.

[0005] Patent Document 1: Japanese Patent Application Laid-Open (kokai) No. 63-211570

[0006] Patent Document 2: Japanese Patent Application Laid-Open (kokai) No. 2000-156234

[0007] Patent Document 3: Japanese Patent Application Laid-Open (kokai) No. 9-97619

[0008] The sealing members known in the art have a porous elastomer, but they complete sealing by contact and pressing. In such sealing, there is a problem that the pressure in the bubbles in the porous body decreases due to gas permeation over time, and the sealing property also decreases due to the decrease in the pressing force. SUMMARY

[0009] In view of the above problems, the present disclosure aims to provide a sealing member capable of suppressing a decrease in sealing property over time. In addition, a method for manufacturing a power generating cell, a fuel cell using the sealing member is provided.

[0010] The present disclosure discloses a sealing member configured between a cathode separator and an anode separator provided in a power generating cell in a fuel cell, which seals the cathode separator and the anode separator by adhesion, the sealing member comprising: a base material; and an adhesion layer configured on at least one surface of the base material, the adhesion layer containing a plurality of bubbles in an adhered state.

[0011] The proportion of the bubbles in the adhesion layer in the adhered state can be 10% or more and 80% or less.

[0012] A power generation cell is disclosed. The power generation cell for a fuel cell is configured by sandwiching a membrane electrode assembly with two separators. A sealing member including an adhesive layer is disposed at an outer periphery of the membrane electrode assembly.

[0013] The adhesive layer can have a peel adhesion strength of 0.2 N / mm or more to the separator.

[0014] A method of manufacturing a fuel cell is disclosed. The method of manufacturing a fuel cell includes: a laminate formation step of disposing a membrane electrode assembly having a sealing member including an adhesive layer disposed at an outer periphery between two separators; and a heating step of heating the laminate formed by the laminate formation step to cause the adhesive layer provided to the sealing member to foam and adhere to the separators by the heating step.

[0015] The adhesive layer or the separators can contain water or a solvent in the laminate formation step, and the adhesive layer can be caused to foam by the water or the solvent in the heating step.

[0016] The separators can have protrusions higher than the thickness of the adhesive layer in the laminate formation step, and the adhesive layer can be caused to be thicker than the height of the protrusions by foaming of the adhesive layer in the heating step.

[0017] According to the present disclosure, the decrease in the sealing performance over time can be suppressed in a fuel cell. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a view of the power generation cell 10 as viewed from above.

[0019] Figure 2 is a cross-sectional view of the power generation section 11, and is a view illustrating the layer structure thereof.

[0020] Figure 3 is a cross-sectional view of the outer periphery section 21, and is a view illustrating the layer structure thereof.

[0021] Figure 4 is a view of a portion of Figure 3 enlarged.

[0022] Figure 5 is a view illustrating the C-C cross section of Figure 4 .

[0023] Figure 6 is a view illustrating the same viewpoint as Figure 5 for another example.

[0024] Figure 7 is a view illustrating the fuel cell stack 30.

[0025] Figure 8is a view for explaining a manufacturing method of a fuel cell.

[0026] Figure 9 is a view that enlarges a part of Figure 8 .

[0027] BRIEF DESCRIPTION OF DRAWINGS

[0028] 10… power generation cell; 11… power generation section; 12… electrolyte membrane; 13… cathode catalyst layer; 14… cathode diffusion layer; 15… cathode separator; 16… anode catalyst layer; 17… anode diffusion layer; 18… anode separator; 21… outer peripheral section; 22… cover plate; 23… resin sheet; 24… base material; 25… adhesive layer; 26… adhesive layer; 30… fuel cell stack. DETAILED DESCRIPTION

[0029] 1. Power generation cell

[0030] Figures 1-3 is a view for explaining a power generation cell 10 related to one embodiment. The power generation cell 10 is a unit member for generating electricity by supplying hydrogen and oxygen (air), and a fuel cell stack is configured by stacking a plurality of such power generation cells 10.

[0031] Figure 1 is a view for observing the power generation cell 10 from above, Figure 2 is a view for explaining a layer structure of a power generation section 11 in the power generation cell 10, Figure 3 is a view for explaining a layer structure of an outer peripheral section 21 in the power generation cell 10.

[0032] 1.1. Power generation section

[0033] The power generation section 11 is, for example, a part that contributes to power generation in a part surrounded by a dotted line in Figure 1 , and is configured by stacking a plurality of layers as shown in the layer structure (a part of A-A cross section) of this power generation section 11 in Figure 2

[0034] ​In the power generation section 11 of the power generation cell 10, one side is a cathode (oxygen supply side) and the other side is an anode (hydrogen supply side) across the electrolyte membrane 12. The cathode has, in order from the electrolyte membrane 12 side, a cathode catalyst layer 13, a cathode diffusion layer 14, and a cathode separator 15. On the other hand, the anode has, in order from the electrolyte membrane 12 side, an anode catalyst layer 16, an anode diffusion layer 17, and an anode separator 18. Among them, the laminated body of the electrolyte membrane 12, the cathode catalyst layer 13, the cathode diffusion layer 14, the anode catalyst layer 16, and the anode diffusion layer 17 is sometimes referred to as a membrane electrode assembly. The thickness of the membrane electrode assembly is typically about 0.4 mm, and the thickness of the power generation cell 10 at the power generation section 11 is typically about 1.3 mm.

[0035] Each layer can be configured as known, for example, as described below.

[0036] 1.1a. Electrolyte membrane

[0037] The electrolyte membrane 12 is a solid polymer film that exhibits good proton conductivity in a wet state. For example, it is configured from a fluorine-based ion exchange membrane, and for example, a carbon-fluorine-based polymer can be used, and specifically, a perfluoroalkyl sulfonic acid-based polymer (Nafion (registered trademark)), and the like can be mentioned.

[0038] The thickness of the electrolyte membrane 12 is not particularly limited, but is 100 μm or less, preferably 50 μm or less, and more preferably 10 μm or less.

[0039] 1.1b. Cathode catalyst layer

[0040] The cathode catalyst layer 13 is a layer that includes a catalyst metal in such a manner that the catalyst metal is supported on a carrier. For example, as the catalyst metal, Pt, Pd, Rh, or an alloy including them can be mentioned. As the carrier, a carbon carrier can be mentioned, and more specifically, carbon particles configured from vitreous carbon, carbon black, activated carbon, coke, natural graphite, and artificial graphite, and the like can be mentioned.

[0041] 1.1c. Anode catalyst layer

[0042] The anode catalyst layer 16 is also, like the cathode catalyst layer 13, a layer that includes a catalyst metal in such a manner that the catalyst metal is supported on a carrier. For example, as the catalyst metal, Pt, Pd, Rh, or an alloy including them can be mentioned. As the carrier, a carbon carrier can be mentioned, and more specifically, carbon particles configured from vitreous carbon, carbon black, activated carbon, coke, natural graphite, and artificial graphite, and the like can be mentioned.

[0043] 1.1d. Cathode diffusion layer

[0044] The cathode diffusion layer 14 can be composed of a porous body having electrical conductivity, for example. As more specific examples, there can be mentioned a carbon porous body (carbon paper, carbon cloth, vitreous carbon, etc.), a metal porous body (metal mesh, foamed metal), and the like.

[0045] If desired, an MPL (microporous layer) can be provided on the cathode diffusion layer. The MPL is a coated thin film provided on the cathode catalyst layer 13 side of the cathode diffusion layer 14. The MPL has a function of adjusting moisture, having hydrophobicity or hydrophilicity as desired. As the MPL, a hydrophobic resin such as polytetrafluoroethylene (PTFE) and an electrically conductive material such as carbon black are typically used as main components.

[0046] 1.1e. Anode diffusion layer

[0047] The anode diffusion layer 17 can be composed of a porous body having electrical conductivity, for example. As more specific examples, there can be mentioned a carbon porous body (carbon paper, carbon cloth, vitreous carbon, etc.), a metal porous body (metal mesh, foamed metal), and the like.

[0048] 1.1f. Cathode separator

[0049] The cathode separator 15 is a member that supplies a reaction gas (air in the present embodiment) to the cathode diffusion layer 14, and has a plurality of grooves 15a on the surface opposite to the cathode diffusion layer 14, which function as reaction gas flow paths. The shape of the grooves is not particularly limited as long as the reaction gas can be supplied to the cathode diffusion layer 14 appropriately, and can be a Serpentine shape in which a plate-like member is formed in a wavy shape, as in the present embodiment. At this time, the plate thickness is typically 0.1 to 0.2 mm, and the height of the concave-convex portions is typically about 0.5 mm.

[0050] When formed in a Serpentine shape, grooves 15b, which function as cooling water flow paths, are formed on the opposite side from the cathode separator 15 between adjacent grooves 15a.

[0051] In addition, with respect to the cathode separator 15, according to Figure 1 It is known that, at a position extending from the power generation portion 11 to the outside, air inlet holes A in , cooling water inlet holes W in , and hydrogen outlet holes H out are provided at portions on the one end side of the grooves 15a and 15b, and air outlet holes Aout, cooling water outlet holes W out , and hydrogen inlet holes H in are provided at portions on the other end side of the grooves 15a and 15b. Here, the grooves 15a communicate with the air inlet holes A in , the air outlet holes Aout, the grooves 15b communicate with the cooling water inlet holes Win cooling water outlet hole W out communicate.

[0052] The material constituting the cathode separator 15 can be any material that can be used as a separator of a power generation unit cell, and can be a gas-impermeable conductive material. As such a material, for example, a dense carbon formed by compressing carbon to be gas-impermeable, a metal plate obtained by press forming, and the like can be cited.

[0053] 1.1g. Anode separator

[0054] The anode separator 18 is a member that supplies a reaction gas (hydrogen) to the anode diffusion layer 17, and has a plurality of grooves 18a on a surface opposite to the anode diffusion layer 17, which function as reaction gas flow paths. As for the shape of the grooves, as long as the reaction gas can be appropriately supplied to the anode diffusion layer 17, it is not particularly limited, and a meandering shape can be cited as in the present embodiment. At this time, the plate thickness is typically 0.1 to 0.2 mm, and the height of the concave-convex is typically about 0.4 mm.

[0055] When formed in a meandering shape, a groove 18b, which functions as a cooling water flow path, is formed on the opposite side from the groove 18a with the anode separator 18 interposed therebetween between adjacent grooves 18a.

[0056] In addition, with respect to the anode separator 18, according to Figure 1 it is known that an air inlet hole A in , a cooling water inlet hole W in , and a hydrogen outlet hole H out are provided at a position that becomes an outer side when extended from the power generation portion 11, at a portion that becomes one end side of the groove 18a, the groove 18b. out , a cooling water outlet hole W out , and a hydrogen inlet hole H in are provided at a portion that becomes the other end side of the groove 18a, the groove 18b. Here, the groove 18a communicates with the hydrogen inlet hole H in , the hydrogen outlet hole H out , the groove 18b communicates with the cooling water inlet hole W in , the cooling water outlet hole W out .

[0057] The material constituting the anode separator 18 can be any material that can be used as a separator of a power generation unit cell, and can be a gas-impermeable conductive material. As such a material, for example, a dense carbon formed by compressing carbon to be gas-impermeable, a metal plate obtained by press forming, and the like can be cited.

[0058] 1.1h. Power generation of the power generation portion

[0059] Although it is well known, the power generation unit cell 10 described above generates power as follows.

[0060] If hydrogen is supplied from the groove 18a of the anode separator 18, the hydrogen passes through the anode diffusion layer 17 and is decomposed into protons (H + ) and electrons (e － ) at the anode catalyst layer 16. The protons pass through the electrolyte membrane 12 and the electrons pass through the conductive wire connected to the outside, and reach the cathode catalyst layer 13, respectively. Here, oxygen (air) is supplied from the groove 15a of the cathode separator 15 to the cathode catalyst layer 13 via the cathode diffusion layer 14, and water (H2O) is generated at the cathode catalyst layer 13 from the protons, the electrons, and the oxygen. The generated water reaches the groove 15a of the cathode separator 15 through the cathode diffusion layer 14 and is discharged.

[0061] That is, in the power generation unit cell 10, the flow of electrons through the conductive wire connected from the anode catalyst layer 16 to the outside is used as the electric current.

[0062] 1.2. Outer peripheral portion

[0063] The outer peripheral portion 21 is an outer peripheral portion of the power generation unit cell 10 outside the power generation portion 11 surrounded by a broken line in Figure 1 , and is made of a plurality of layers stacked as shown in the layer structure (B-B cross section) in Figure 3 .

[0064] As is apparent from Figure 3 , the outer peripheral portion 21 has the following structure in the present embodiment.

[0065] The end surface of the electrolyte membrane 12, the anode catalyst layer 16, and the anode diffusion layer 17 is a position protruding (advancing) from the end surface of the cathode catalyst layer 13, and is stacked so as to be substantially the same position, and the cathode diffusion layer 14 is a position protruding (advancing) from the end surface of the cathode catalyst layer 13, but is a position retreating from the electrolyte membrane 12.

[0066] On the cathode side surface of the electrolyte membrane 12, a cover plate 22 is disposed so as to extend from the end surface of the cathode catalyst layer 13 and extend toward the end surface side of the electrolyte membrane 12. The cover plate 22 is a sheet made of a material (for example, nylon) that does not allow reaction gases such as hydrogen and oxygen to pass through. The one end side of the cover plate 22 is disposed between the electrolyte membrane 12 and the cathode diffusion layer 14.

[0067] In addition, a resin sheet 23 is disposed on the cathode side of the other end side of the cover plate 22. As is apparent from Figure 2 , the resin sheet 23 is disposed so that one end surface thereof opposes the end surface of the cathode diffusion layer 14 with a gap therebetween, and the other end surface thereof opposes the end surface of the electrolyte membrane 12 with a gap therebetween. Figure 2The middle section is omitted, but it extends in a manner that protrudes significantly relative to the electrolyte membrane 12. The resin sheet 23 will be described further later.

[0068] The gap can absorb the dimensional changes caused by the linear expansion of the resin sheet 23 and the cathode diffusion layer 14, and can suppress the occurrence of damage caused by expansion and contraction.

[0069] The cathode separator 15 and the anode separator 18 are configured such that, like the electrode section 11, the aforementioned layers are sandwiched between them. Therefore, the spacing between the cathode separator 15 and the anode separator 18 is curved in a manner varying due to the layers sandwiched between them. Figure 2 It can be seen that in the part where only the resin sheet 23 is provided, the space is narrowed in part, and the resin sheet 23 is fixed by the cathode diaphragm 15 and the anode diaphragm 18.

[0070] Furthermore, in the outer peripheral portion 21, since neither the cathode partition 15 nor the anode partition 18 requires a flow path, grooves 15a and 18a are not formed (wherein, from Figure 3 It can be seen that this does not prevent the formation of grooves in a certain part.

[0071] 1.2a. Resin sheets

[0072] The resin sheet 23 functions as a sealing component that seals the space between the cathode separator 15 and the anode separator 18 in the outer periphery 21 of the power generation cell 10. Figure 4 The enlarged representation is Figure 3 The region indicated by IV. Additionally, in Figure 5 It shows Figure 4 An example of a CC section.

[0073] The resin sheet 23 includes: a substrate 24; an adhesive layer 25 disposed on one side of the substrate 24 (facing the cathode side); and an adhesive layer 26 disposed on the other side of the substrate 24 (facing the anode side). The power generation section 11 is sealed by bonding the adhesive layer 25 to the cathode separator 15 and the adhesive layer 26 to the anode separator 18.

[0074] The substrate 24 possesses electrical insulation and airtightness, and is formed from a thermoplastic resin material with a relatively high melting point. Examples of such materials include polyethylene naphthalate, polyphenylene ether, and polyphenylene sulfide. By using a resin material with a high melting point, even when heating occurs to generate bubbles in the adhesive layers 25 and 26 as described later, the substrate 24 can be prevented from melting, thus minimizing changes in size and shape.

[0075] The thickness of the substrate 24 is not particularly limited, but is preferably 0.05 mm or more and 0.25 mm or less.

[0076] The adhesive layer 25 and the adhesive layer 26 are layers that have adhesiveness in a state of being adhered and include a plurality of bubbles.

[0077] The adhesive layer 25 and the adhesive layer 26 can be applied with a material exhibiting adhesiveness, and for example, a modified polyolefin in which a functional group (anhydromaleic acid, an epoxy group, or the like) is introduced to a polyolefin to impart adhesiveness, or the like can be cited. More specifically, ADLIER (registered trademark) of Mitsui Chemicals, Inc. is available.

[0078] The bubbles are generated by a manufacturing method described later, and are not particularly limited in terms of the shape and the size. Figure 5 It is known that the shape and the size thereof are various and are not limited. The size of the bubbles, which is a reference, is preferably about 0.6 mm or less in diameter from the viewpoint of the adhesiveness. Figure 5 from the viewpoint of the adhesiveness. Figure 6 Three other examples are illustrated in the drawings. Figure 6 are the same view as Figure 5 the drawings.

[0079] In addition, the proportion of the bubbles (a bubble rate) in the adhesive layer 25 and the adhesive layer 26 is 10% or more and 80% or less. More preferably, it is 30% or more and 80% or less, and further preferably, it is 50% or more and 80% or less.

[0080] The bubble rate is measured from the area proportion of the bubbles in a field of view (a circle of 2 mm in diameter) by observing a cross section (C-C cross section) of a face parallel to the layer face at the center of the layer thickness direction of the adhesive layer using an X-ray CT or an optical microscope. Thus, by foaming and expanding the adhesive layer while having the adhesion strength of the adhesive layer, it is possible to follow the unevenness of the separator. Among them, if the bubble rate is less than 10%, there is a concern that the volume of the gap-filling is insufficient and the sealing property is insufficient. In addition, if the bubble rate exceeds 80%, there is a tendency that the adhesion strength is reduced. From the above viewpoint, by moderately including the bubbles, it is possible to obtain an improvement in the adhesiveness and a function of gap-filling (sealing property).

[0081] Among them, the adhesion strength of the adhesive layer 25 and the adhesive layer 26 is configured to be greater than 0.2 N / mm in a measurement related to 90° peeling according to JIS K 6854-1: 1999 (ISO 8510-1: 1990) or a measurement related to T-peeling according to JIS K 6854-3: 1999 (ISO 11339: 1993).

[0082] In addition, on the surface of the cathode separator 15 to which the adhesive layer 25 is adhered and the surface of the anode separator 18 to which the adhesive layer 26 is adhered, unevenness corresponding to the unevenness on the surface of each separator is formed due to foaming expansion at the time of adhesion (described later). That is, on the protrusions on the surface of the separator, recesses are formed in the adhesive layer, and on the recesses on the surface of the separator, protrusions are formed in the adhesive layer, and the adhesive is filled between the base material and the separator along the unevenness to form the adhesive layer.

[0083] As such protrusions on the surface of the separator, there are protrusions (height of about 0.04 mm) intentionally provided for improving sealing and unintentional protrusions generated at the time of manufacture.

[0084] On the other hand, as recesses on the surface of the separator, there are damages and defects.

[0085] Furthermore, although the above-described manner of including bubbles in both the adhesive layer 25 and the adhesive layer 26 is described here, it is not limited thereto, and the adhesive layer can be in the above-described manner in either the adhesive layer 25 or the adhesive layer 26.

[0086] 2. Fuel cell stack

[0087] The fuel cell stack 30 is a member in which the above-described power generating single cell 10 is overlapped by a plurality of (about 50 to 400) to collect electricity from the plurality of power generating single cells 10. Figure 7 The outline of the structure thereof is shown. The fuel cell stack 30 is provided with a stack case 31, an end plate 32, a plurality of power generating single cells 10, a current collecting plate 34, and a force applying member 35.

[0088] The stack case 31 is a frame in which the plurality of power generating single cells 10, the current collecting plate 34, and the force applying member 35 overlapped are housed inside. In the present embodiment, the stack case 31 is a quadrangular cylindrical shape, one end of which is open, the other end of which is closed, and a plate-shaped piece is projected to the side opposite to the opening along the edge of the opening, and a flange 31a is formed.

[0089] The end plate 32 is a plate-shaped member that closes the opening of the stack case 31. The end plate 32 is fixed to the stack case 31 in a manner of being capped to the stack case 31 by a bolt, a nut, or the like at the overlapping portion with the flange 31a of the stack case 31.

[0090] The power generating single cell 10 is as described above. Such power generating single cells 10 are overlapped by a plurality. At this time, it is configured that the cathode separator 15 of one power generating single cell 10 overlaps the anode separator 18 of the adjacent power generating single cell 10. Further, the cooling water flow path is formed by the groove 15b of the cathode separator 15 overlapping the groove 18b of the anode separator 18.

[0091] The current collector 34 is a component that collects electricity from the stacked power-generating cells 10. Therefore, the current collector 34 is disposed at one end and the other end of the stacked structure of the power-generating cells 10 in the stacking direction, with one end being the positive terminal and the other the negative terminal. It is configured to be electrically connected to an external source by having terminals (not shown) connected to the current collector 34.

[0092] The force-applying component 35 is housed inside the battery pack casing 31 and applies pressure to the stacked structure of the single-cell generator 10 along its stacking direction. For example, a disc spring can be used as the force-applying component.

[0093] 3. Manufacturing methods for single-cell power generation and fuel cell stacks

[0094] The power-generating single cell disclosed herein can be manufactured, for example, as follows.

[0095] 3.1. Laminated body formation process

[0096] The layers of the power-generating single cell 10 described above are arranged between the cathode separator 15 and the anode separator 18, similar to the above arrangement. However, at this time, the resin sheet 23 is thin because its adhesive layers 25 and 26 do not contain air bubbles (unfoamed), so... Figure 8 , Figure 9 ( Figure 9 yes Figure 8 As shown in the enlarged view of the portion indicated by IX, the spaces between the cathode separator 15 and the resin sheet 23, and between the anode separator 18 and the resin sheet 23, are not filled by the adhesive layers 25 and 26. At this time (before foaming), the thickness of the adhesive layers 25 and 26 is not particularly limited, but is approximately 0.02 mm to 0.06 mm. Furthermore, it is preferable that the bubble rate before foaming is 5% or less.

[0097] When protrusions are intentionally provided in the cathode separator 15 and the anode separator 18, the thickness of the adhesive layer 25 and the adhesive layer 26 can be thinner than the amount of protrusion.

[0098] Furthermore, at this time, at least one of the adhesive layer 25, adhesive layer 26, cathode separator 15, and anode separator 18 may contain a solvent (water, organic solvent (toluene, etc.)) for promoting foaming.

[0099] 3.2. Heating process

[0100] Next, after configuring the layers as described above, they are constrained and heated using a metal mold or similar means, causing adhesive layers 25 and 26 to foam and... Figures 3-6 This is filled between the cathode partition 15 and the substrate 24, and between the anode partition 18 and the substrate 24. Thus, the adhesive layer fills the space between the inner partition and the substrate, bonding the partitions together.

[0101] The temperature of heating is above the melting point of the adhesive of the adhesive layer (preferably +20°C of the melting point) and above the boiling point of the solvent (water: 100°C or higher, toluene: 111°C or higher).

[0102] 3.3. Production of fuel cell stack

[0103] The power generation cell 10 is produced by the above process, a plurality of the power generation cells 10 are prepared and overlapped, and a fuel cell stack 30 is produced by a publicly known method such as Figure 7 as shown, whereby the fuel cell stack 30 can be produced.

[0104] 4. Effects and the like

[0105] According to the present disclosure, by foaming the adhesive layer using heat at the time of adhesion, adhesion and gap filling can be performed at the same time. That is, even if the separator has protrusions and depressions, sealing can be performed by filling the gaps with the foamed adhesive layer. Thus, compared to the adhesive layer without foaming, adhesion can be firmly performed due to an increase in the contact area.

[0106] In addition, since the adhesive layer according to the present disclosure is sealed by adhesion force, not by elastic reaction force, a decrease in sealing performance due to time series can be suppressed, and durability is good.

[0107] In addition, since the thickness of the adhesive layer is increased by foaming, the adhesive layer before foaming can be thin (can be thinner than the height of the protrusions of the separator), and the adhesive layer can be efficiently formed from the viewpoint of productivity and cost.

Claims

1. A sealing member configured between a cathode separator and an anode separator provided in a power generating cell in a fuel cell, and bonding the cathode separator and the anode separator to seal, wherein The sealing member is provided with: a base material; and an adhesive layer disposed on at least one face of the base material, the adhesive layer containing air bubbles in the state of being adhered, the proportion of the air bubbles in the adhesive layer in the state of being adhered being 10% or more and 80% or less in order to obtain an improvement in adhesion and a function of sealing.

2. A power generating cell that is a power generating cell for a fuel cell using a configuration in which a membrane electrode assembly is sandwiched by two separators, wherein the sealing member according to claim 1 is disposed at an outer peripheral portion of the membrane electrode assembly, and the adhesive layer is adhered to the separator.

3. The power generating cell according to claim 2, wherein the peeling adhesion strength of the adhesive layer to the separator is 0.2 N / mm or more.

4. A method for manufacturing a fuel cell, for manufacturing a fuel cell, wherein including: a laminate formation step of disposing a membrane electrode assembly to which a sealing member including a base material and an adhesive layer is disposed at an outer periphery between two separators; and a heating step of heating a laminate formed by the laminate formation step, the adhesive layer of the sealing member is foamed by the heating step so as to adhere the adhesive layer to the separator.

5. The manufacturing method of a fuel cell according to claim 4, wherein in the laminate formation step, the adhesive layer or the separator contains a solvent, and in the heating step, the adhesive layer is foamed by foaming of the solvent.

6. The manufacturing method of a fuel cell according to claim 4 or 5, wherein the separator has a protruding portion having a height higher than the thickness of the adhesive layer in the laminate formation step, and the adhesive layer is made thicker than the height of the protruding portion by foaming of the adhesive layer in the heating step.

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