JP2022048654A - Manufacturing method of fuel battery cell - Google Patents

Abstract

To provide a manufacturing method for a fuel battery cell that can prevent a thermoplastic resin that constitutes a sealing member (frame) from invading excessively into a flow path by heat pressing at the time of forming the fuel battery cell.SOLUTION: A recess is formed on the top of a rib provided by a separator, and when the rib and a frame are bonded by heat pressing, the thermoplastic resin on the surface of the frame is allowed to penetrate into the recess of the rib, and the excessive intrusion of the thermoplastic resin into the flow path formed between the adjacent ribs is suppressed.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing a fuel cell.

A fuel cell is known that generates electricity by chemically reacting an anode gas such as hydrogen with a cathode gas such as oxygen.

The fuel cell supplies an anode gas (fuel gas) such as hydrogen and a cathode gas (oxidant gas) such as oxygen to two electrically connected electrodes, respectively, and electrochemically oxidizes the fuel. By letting it, chemical energy is directly converted into electrical energy.

At the anode (fuel electrode) to which hydrogen is supplied as the anode gas, the reaction of the following formula (1) proceeds.
H ₂ → 2H ⁺ + 2e -... ⁽ 1)

The electrons (e ⁻ ) generated in the above equation (1) reach the cathode (oxidizing agent electrode) after working with an external load via an external circuit. On the other hand, the proton (H ⁺ ) generated by the above formula (1) moves from the anode side to the cathode side in the electrolyte membrane sandwiched between the anode and the cathode.

On the other hand, at the cathode, the proton (H ⁺ ) generated by the above formula (1) and passing through the electrolyte membrane, oxygen supplied as the cathode gas, and the electrons (e) generated by the above formula (1) and passed through the external circuit. ^- ) And the reaction of the following formula (2) proceed.
2H ^＋ ＋ 1 / 2O ₂ ＋ 2e ^－ → H ₂ O ・ ・ ・ (2)

Therefore, the chemical reaction represented by the following formula (3) proceeds in the entire battery, an electromotive force is generated, and electrical work is performed on the external load.
H ₂ + 1 / 2O ₂ → H ₂ O ・ ・ ・ (3)

Such a fuel cell usually has a configuration in which a plurality of single cells (fuel cell cells) having a membrane electrode assembly in which an electrolyte membrane is sandwiched between a pair of electrodes are laminated. Among them, the solid polymer electrolyte fuel cell using the solid polymer electrolyte membrane as the electrolyte membrane has advantages such as easy miniaturization and operation at a low temperature, and therefore, particularly for mobile devices and the like. It is expected as a power source for portable or mobile bodies such as electric vehicles.

Here, as a configuration of a single cell (fuel cell) of a solid polymer electrolyte fuel cell, a membrane electrode assembly or a membrane electrode gas diffusion layer assembly is arranged between an anode side separator and a cathode side separator. Laminates are known. Here, the membrane electrode assembly is a laminate in which the anode side catalyst layer, the electrolyte membrane, and the cathode side catalyst layer are laminated in this order, and the membrane electrode gas diffusion layer assembly is the anode side gas diffusion layer and the membrane. The electrode assembly and the cathode side gas diffusion layer are laminated in this order.

Further, in a fuel cell having such a configuration, a frame is arranged at a peripheral portion of a membrane electrode assembly or the like, and the frame and a pair of separators are adhered to each other.

Regarding such a fuel cell, for example, in Patent Document 1, a seal member (frame) arranged in a peripheral portion of a membrane electrode assembly is heated by a press mold in a state of being sandwiched between a first separator and a second separator. A method of pressing to form a fuel cell has been proposed. It is described that the flow path is formed by the separator and the seal member (frame).

In Patent Document 2, a film-shaped sealing member is arranged on the peripheral edge of the membrane electrode gas diffusion layer joint, and the separator has a convex portion protruding from the surface facing the sealing member toward the sealing member. There has been proposed a fuel cell in which the convex portion is embedded in a seal member and joined by pressing them.

Further, in general, the separator constituting the fuel cell has a reaction gas manifold for distributing the reaction gas to the reaction gas flow path and a cooling medium manifold for distributing the cooling medium to the cooling medium flow path at the outer edge thereof. Is formed.

Regarding the structure around the manifold, Patent Document 3 proposes a technique in which ribs are provided on the surface of the separator around the manifold to form a flow path between adjacent ribs.

Japanese Unexamined Patent Publication No. 2020-013734 Japanese Unexamined Patent Publication No. 2017-139178 Japanese Patent Application Laid-Open No. 2015-097145

In the bonding method described in Patent Document 1 and Patent Document 2, as described in Patent Document 3, a separator having a plurality of ribs in the vicinity of the manifold at the cell end is used to form a flow path between adjacent ribs. In this case, the thermoplastic resin constituting the seal member (frame) excessively flowed into the flow path between the ribs by the heating press, and the flow path was partially filled.

Since the cross-sectional area of the flow path in which the thermoplastic resin has excessively penetrated becomes small, sufficient reaction gas is not provided to the membrane electrode assembly, which causes deterioration of the performance of the fuel cell.

The present invention has been made in view of the above background, and suppresses excessive intrusion of the thermoplastic resin constituting the seal member (frame) into the flow path by the thermal press when forming the fuel cell. It is an object of the present invention to provide a method for manufacturing a fuel cell, which can be performed.

The present inventors have conducted diligent studies in order to solve the above problems. Then, a recess is formed on the top of the rib provided by the separator, and when the rib and the frame are bonded by a hot press, if the thermoplastic resin on the surface of the frame penetrates into the recess of the rib, the adjacent ribs are adjacent to each other. It is considered that the excessive invasion of the thermoplastic resin into the flow path formed between the two can be suppressed, and the present invention has been completed. That is, the present invention is as follows.

Placing the frame on the peripheral edge of the membrane electrode assembly and adhering the separator onto at least one main surface of the frame by hot pressing.
Including
The separator is provided with a plurality of ribs having recesses at the top on a surface facing the frame, and the frame is made of a thermoplastic resin at least a part of the surface thereof.
Thereby, the heat press allows the thermoplastic resin to penetrate into the recesses while adhering the ribs to the frame to form a flow path between the adjacent ribs.
How to make a fuel cell.

According to the method of the present invention for manufacturing a fuel cell, a flow path in which a thermoplastic resin for bonding is formed between adjacent ribs of the separator during hot pressing for bonding the separator and the frame. It is possible to suppress excessive invasion into the fuel cell. As a result, the cross-sectional area of the flow path can be maintained, and the reaction gas can be sufficiently provided to the membrane electrode assembly, whereby the performance of the fuel cell can be maintained.

Further, during hot pressing, the thermoplastic resin constituting the surface of the frame tends to remain between the frame and the separator, so that the sealing performance of the fuel cell can be improved.

It is a figure explaining the manufacturing method of the fuel cell which concerns on 1st Embodiment of this invention. It is a figure explaining the manufacturing method of the conventional fuel cell. It is a figure explaining the manufacturing method of the fuel cell which concerns on 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments, but can be variously modified and implemented.

<< Manufacturing method of fuel cell >>
The method for manufacturing a fuel cell of the present invention includes arranging a frame on the peripheral edge of a membrane electrode assembly, and adhering a separator on at least one main surface of the frame by hot pressing. Then, it is possible to prevent the thermoplastic resin constituting the seal member (frame) from excessively invading the flow path by the heat press when forming the fuel cell.

<Fuel cell>
The fuel cell to which the method for manufacturing a fuel cell of the present invention can be applied is not particularly limited, and a known fuel cell can be applied. The fuel cell is a stack in which a plurality of fuel cell cells are stacked.

A general fuel cell that forms a stack is a laminated body in which a membrane electrode assembly or a membrane electrode gas diffusion layer assembly is arranged between an anode-side separator and a cathode-side separator.

The membrane electrode assembly is a laminate in which the anode side catalyst layer, the electrolyte membrane, and the cathode side catalyst layer are laminated in this order, and the membrane electrode gas diffusion layer assembly is the anode side gas diffusion layer and the membrane electrode assembly. , And the cathode side gas diffusion layer are laminated in this order. That is, in a laminate that becomes a fuel cell of a general fuel cell, the side of each surface of the electrolyte membrane is an anode (An) or a cathode (Ca).

(Electrolyte membrane)
The electrolyte membrane in the fuel cell is arranged between the anode-side catalyst layer and the cathode-side catalyst layer. The electrolyte membrane has a function of blocking the flow of electrons and gas and moving protons (H ⁺ ) generated at the anode from the catalyst layer on the anode side to the catalyst layer on the cathode side.

The electrolyte membrane exhibits electron conductivity, and in the case of a solid polymer electrolyte fuel cell, a solid polymer electrolyte membrane is used as the electrolyte membrane.

Examples of the electrolyte membrane include an ion exchange membrane having ionic conductivity and formed of a polyelectrolyte resin containing a sulfonic acid group such as perfluorosulfonic acid (PFSA) ionomer. The film is not limited to the sulfonic acid group, and may be a film containing another ion exchange group (electrolyte component) such as a phosphoric acid group or a carboxylic acid group.

(Catalyst layer)
The catalyst layer formed on each surface of the electrolyte membrane has different functions on the anode side and the cathode side. The anode-side catalyst layer has a function of decomposing hydrogen (H ₂ ), which is an anode gas, into protons (H ⁺ ) ^and electrons (e-). On the other hand, the cathode-side catalyst layer has a function of generating water (H ₂ O) from protons (H ⁺ ), electrons (e ⁻ ), and oxygen (O ₂ ) contained in the cathode gas.

The anode-side and cathode-side catalyst layers can be made of similar materials. For example, a conductive carrier carrying a catalyst such as platinum or a platinum alloy is used, and more specifically, for example, a catalyst-supported carbon in which a catalyst is supported on carbon particles such as carbon black that functions as a conductive substance. Examples thereof include a layer composed of particles and an electrolyte component that exhibits proton conductivity by an ion exchange group, which is a component of the above-mentioned electrolyte film. The catalyst-supported carbon particles may be a layer formed by being coated with an electrolyte component such as an ionomer having proton conductivity.

(Gas diffusion layer)
The gas diffusion layer has a function of diffusing the supplied reaction gas to make it uniform and distributing the gas to the adjacent catalyst layer. The gas diffusion layer is generally a laminate in which a microporous layer is laminated on a diffusion layer base material layer, and the microporous layer (MPL) is arranged so as to face an adjacent catalyst layer. To.

The diffusion layer base material layer constituting the gas diffusion layer can be formed of, for example, a carbon porous body such as carbon paper or carbon cloth, or a metal porous body such as a metal mesh or foamed metal.

The microporous layer (MPL), which exists on the diffusion layer base material layer and is adjacent to the catalyst layer, is generally a layer containing carbon particles and a water-repellent resin as main components.

Examples of the carbon particles include particles such as carbon black, graphene, and graphite. Examples of the water-repellent resin include fluorine-based polymer materials such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyhexafluoropropylene, and tetrafluoroethylene-hexafluoropropylene copolymer, polypropylene, and the like. Examples include polyethylene.

(Separator)
The separator sandwiches a laminated body as a power generation element from both sides. The anode side separator is provided with a plurality of ribs for forming a flow path (anode side flow path) through which the anode gas flows, and the cathode side separator is provided with a flow path (cathode side flow) through which the cathode gas flows. It is provided with multiple ribs to form the road). And, in general, these plurality of ribs are arranged substantially in parallel.

In general, the separator constituting the fuel cell has a reaction gas manifold for distributing the fluid to the reaction gas flow path and a cooling medium manifold for distributing the cooling medium to the cooling medium flow path at the outer edge thereof. Is formed. In general, the plurality of ribs included in the separator extend substantially in parallel toward the manifold.

In the method for manufacturing a fuel cell of the present invention, the thermoplastic resin for bonding excessively penetrates into the flow path formed between the adjacent ribs during the hot pressing for bonding the separator and the frame. To maintain the cross-sectional area of the flow path. Therefore, the method for manufacturing a fuel cell of the present invention can enjoy the highest effect when applied around the reaction manifold.

The ribs included in the separator may be made of the same material as the separator body, or may be made of a different material. As the material constituting the separator and the rib, a known material can be applied as the separator of the fuel cell, and examples thereof include metals and various resins.

Further, the separator main body and the rib may be manufactured by integral molding, or may be manufactured as separate parts and the rib may be joined to the separator main body.

The rib provided in the separator used in the present invention has a recess at the top. The plurality of ribs are provided on the surface facing the frame.

The shape of the concave portion formed on the top of the rib is not particularly limited, and for example, even a rectangular parallelepiped groove having corners is a semicircular columnar groove composed of a semicircular curved surface. You may. Further, the recesses may be continuously provided in the entire rib or intermittently provided along the axis in the direction of forming the flow path.

The size of the recess is also not particularly limited. For example, if the width is about half the width of the rib and the depth is about half the height of the rib, the frame can be pressed while maintaining the strength of the rib when hot-pressing the frame to bond the rib. The constituent thermoplastic resin can be sufficiently penetrated into the recess.

Here, the rib provided with the separator and the concave shape provided with the rib will be described with reference to the drawings. FIG. 1 is a diagram illustrating a method for manufacturing a fuel cell according to the first embodiment of the present invention. Further, FIG. 3 is a diagram illustrating a method for manufacturing a fuel cell according to the second embodiment of the present invention.

FIG. 1 according to the first embodiment is an example of manufacturing a fuel cell by sandwiching the frame 3 between the first separator 1 and the second separator 2. The first separator 1 and the second separator 2 in FIG. 1 are separators applied to the method for manufacturing a fuel cell of the present invention.

The first separator 1 used in the first embodiment includes ribs 1a and 1c on a surface facing the frame 3. Then, on the tops of the ribs 1a and 1c, a rectangular parallelepiped-shaped recess is formed over the entire long axis of the rib.

FIG. 1 according to the first embodiment shows only two ribs, the rib 1a and the rib 1c, but the first separator 1 used in the first embodiment has a large number of ribs substantially in parallel. It is provided. Further, the rib 1a and the like included in the first separator 1 used in the first embodiment are made of the same material as the separator main body.

Although the second separator 2 used in the first embodiment is not shown in FIG. 1, the second separator 2 may be provided with a plurality of ribs on the surface facing the frame 3 like the first separator 1. Then, a rectangular parallelepiped-shaped recess may be formed on the top of the rib over the entire long axis of the rib.

In the first embodiment, the plurality of ribs (for example, ribs 1a and 1c) included in the first separator 1 and the plurality of ribs included in the second separator 2 are positioned so as not to face each other with the frame 3 interposed therebetween. Arranged and used.

FIG. 3 according to the second embodiment is an example in which the frame 7 is sandwiched between the first separator 5 and the second separator 6 to manufacture a fuel cell. The first separator 5 and the second separator 6 in FIG. 3 are separators applied to the method for manufacturing a fuel cell of the present invention.

The first separator 5 in FIG. 3 is provided with ribs 5a and 5c on a surface facing the frame 7. Then, on the tops of the ribs 5a and 5c, a substantially semi-cylindrical concave portion formed by a curved surface is formed over the entire long axis of the rib.

FIG. 3 according to the second embodiment shows only two ribs, the rib 5a and the rib 5c, but the first separator 5 used in the second embodiment has a large number of ribs substantially in parallel. It is provided. Further, the rib 5a and the like included in the first separator 5 used in the second embodiment are made of the same material as the separator main body.

Although the second separator 6 used in the second embodiment is not shown in FIG. 3, like the first separator 5, the second separator 6 may be provided with a plurality of ribs on the surface facing the frame 3. Then, on the top of the rib, a substantially semi-cylindrical concave portion formed by a curved surface may be formed over the entire long axis of the rib.

The plurality of ribs (for example, ribs 5a and 5c) included in the first separator 5 used in the second embodiment and the plurality of ribs included in the second separator 6 are arranged at positions not facing each other with the frame 7 interposed therebetween. And used.

<Frame>
The frame used in the method for manufacturing a fuel cell of the present invention is arranged on the peripheral edge of a membrane electrode assembly, and a separator is adhered to at least one main surface of the frame by a hot press.

The shape of the frame is not particularly limited. Generally, the outer shape thereof is substantially the same as the outer shape of the manufactured fuel cell. The frame has a space cut out in a substantially central portion having a shape and size substantially the same as the laminated surface of the membrane electrode assembly, and in the manufacture of a fuel cell, the membrane electrode assembly is formed in the space. The separator is hot-pressed onto at least one of the main surfaces of the frame.

Here, the "main surface" in the present specification means a surface that is not an end surface of the frame. That is, when the membrane electrode assembly is placed in the space cut out in the center of the frame, it means a surface that is substantially parallel to the laminated surface of the elements constituting the membrane electrode assembly.

At least a part of the surface of the frame applied to the method for manufacturing a fuel cell of the present invention is made of a thermoplastic resin. Then, when manufacturing the fuel cell, the thermoplastic resin is melted by the heat of the hot press, and the molten thermoplastic resin is allowed to penetrate into the recess existing at the top of the rib provided in the separator, and the rib and the frame are formed. The ribs of the separator and the frame are adhered to each other by contacting them and then solidifying them.

The material and structure of the frame are not particularly limited as long as at least a part of the surface thereof is made of a thermoplastic resin. For example, the entire frame may be made of a thermoplastic resin that contributes to adhesion, or the thermoplastic resin that contributes to adhesion may be arranged only on the surface of the separator facing the rib. ..

Among them, it is preferable that the frame is a laminated body having a layer made of a thermoplastic resin that contributes to adhesion on both sides of the frame, and a core layer is arranged between the layers. Since the frame has a core layer, the strength of the frame can be ensured in the heat pressing at the time of bonding the frame and the separator.

The type of thermoplastic resin that constitutes the frame and contributes to adhesion is not particularly limited as long as it is melted by a hot press. For example, maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, epoxy-modified polyethylene, epoxy-modified polypropylene, acid-modified polyethylene, acid-modified polypropylene and the like can be mentioned.

When the frame has a core layer, the material constituting the core layer is not particularly limited. Among them, a material having gas-sealing property and insulating property is preferable, and for example, polyethylene (PE), polypropylene (PP), polycarbonate (PC), polyphenylsulfone sulfide (PPS) polyethylene terephthalate (PET), polyethylene na. Phthalate (PEN), polyamide (PA), polyimide (PI), polystyrene (PS), polyphenylene ether (PPE), polyetheretherketone (PEEK), cycloolefin, polyethersulfone (PES), polyphenylsulfone (PPSU) ), Resins such as liquid crystal polymer (LCP) and epoxy, or alloy resins thereof, and rubbers such as EPDM, fluorine-based rubber, and silicon-based rubber.

The thickness of the frame is not particularly limited, and can be appropriately set according to the thickness of the membrane electrode assembly arranged in the space of the frame.

Further, in general, the frame has a manifold having substantially the same shape and size as the separator at a position at the same position when the separator is bonded. The method for manufacturing a fuel cell of the present invention exhibits the highest effect, especially when applied around a reaction gas manifold for distributing a reaction gas to a reaction gas flow path. Therefore, it is preferable that the thermoplastic resin present on the surface of the frame and contributing to adhesion is present at least around the reaction gas manifold.

Here, the configuration of the frame will be described with reference to the drawings. FIG. 1 is a diagram illustrating a method for manufacturing a fuel cell according to the first embodiment of the present invention. Further, FIG. 3 is a diagram illustrating a method for manufacturing a fuel cell according to the second embodiment of the present invention.

The frame 3 is used in the manufacturing method according to the first embodiment shown in FIG. 1, and the frame 7 is used in the manufacturing method according to the second embodiment shown in FIG.

Both the frame 3 and the frame 7 have a three-layer laminated structure, and the surfaces 3a, 3c, 7a, and 7c of the frame 3 and the frame 7 are layers made of a thermoplastic resin. Further, 3b and 7b, which are the central layers of the laminated body, are core layers.

<< Conventional embodiment >>
A method for manufacturing a fuel cell according to a conventional embodiment will be described with reference to FIG.

FIG. 2A is a diagram showing a state in which the first separator 10 and the second separator 20 are arranged on both sides of the frame 30. FIG. 2B is a diagram showing a fuel cell obtained by hot-pressing and adhering a first separator 10, a frame 30, and a second separator 20 arranged in FIG. 2A.

Similar to the present invention, the method for manufacturing a fuel cell according to a conventional embodiment is to dispose a frame on the peripheral edge of a membrane electrode assembly, and to heat press on at least one main surface of the frame. Includes bonding separators.

However, unlike the present invention, it is carried out by using a separator having a plurality of ribs having no recess on the top.

In the conventional method for manufacturing a fuel cell, as shown in FIGS. 2A and 2B, a plurality of ribs such as ribs 10a and ribs 10c having no recess on the top are provided. A first separator 10 provided and a second separator 20 having the same form as the first separator 10 are used. As the frame 30, a laminate in which the thermoplastic resin layer 30a and the thermoplastic resin layer 30c are arranged on both sides of the core layer 30b is used.

In the conventional embodiment, the frame 30 is arranged at the peripheral edge of the membrane electrode assembly (not shown) which is a power generation element of the fuel cell. Subsequently, the first separator 10 and the second separator 20 are arranged on both sides of the frame 30 and the membrane electrode assembly (not shown) so as to sandwich the frame 30 and the membrane electrode assembly (not shown).

At this time, the ribs 10a and 10c included in the first separator 10 are arranged so as to face the frame. Similarly, the plurality of ribs included in the second separator 20 are also arranged so as to face the frame.

The plurality of ribs (for example, ribs 10a and 10c) included in the first separator 10 and the plurality of ribs included in the second separator 20 are arranged at positions not facing each other with the frame 30 interposed therebetween. Therefore, the ribs included in the second separator 20 are not shown in FIGS. 2 (a) and 2 (b).

Subsequently, in the conventional embodiment, the first separator 10, the frame 30, and the second separator 20 arranged as shown in FIG. 2A are hot-pressed by the press 40 to press both sides of the frame 30. The first separator 10 and the second separator 20 are adhered on the main surface.

As shown in FIG. 2B, in the conventional embodiment, since the separator does not have a recess on the top of the rib, the frame 30 is configured by a hot press for adhering the frame and the separator. The thermoplastic resin layer 30a may excessively flow between the ribs 10a and the ribs 10c included in the first separator 10 due to heating and pressurization.

As a result, the flow path formed between the rib 10a and the rib 10c is partially filled with the thermoplastic resin layer 30a, and the cross-sectional area of the flow path becomes small. Therefore, the reaction gas is applied to the membrane electrode assembly. It becomes difficult to provide it sufficiently, and the performance of the fuel cell may be deteriorated.

<< First Embodiment >>
The method for manufacturing the fuel cell of the present invention according to the first embodiment will be described with reference to FIG.

FIG. 1A is a diagram showing a state in which the first separator 1 and the second separator 2 are arranged on both sides of the frame 3. FIG. 1B is a diagram showing a fuel cell obtained by hot-pressing and adhering a first separator 1, a frame 3, and a second separator 2 arranged in FIG. 1A.

In the method for manufacturing a fuel cell according to the first embodiment of the present invention, as shown in FIGS. 1 (a) and 1 (b), the rib 1a having the rectangular parallelepiped recess 1b and the recess 1d are provided. A first separator 1 having a plurality of ribs such as ribs 1c, a frame 3 which is a laminated body in which a thermoplastic resin layer 3a and a thermoplastic resin layer 3c are arranged on both sides of a core layer 3b, and a second frame 3. Separator 2 is used. Each part is as described above.

In the first embodiment, the frame 3 is arranged at the peripheral edge of the membrane electrode assembly (not shown) which is a power generation element of the fuel cell. Subsequently, the first separator 1 and the second separator 2 are arranged on both sides of the frame 3 and the membrane electrode assembly (not shown) so as to sandwich them.

At this time, the ribs 1a and ribs 1c included in the first separator 1 are arranged so as to face the frame. Similarly, the plurality of ribs included in the second separator 2 are also arranged so as to face the frame.

The plurality of ribs (for example, ribs 1a and 1c) included in the first separator 1 and the plurality of ribs included in the second separator 2 are arranged at positions not facing each other with the frame 30 interposed therebetween. .. Therefore, the ribs included in the second separator 2 are not shown in FIGS. 1 (a) and 1 (b).

Subsequently, in the first embodiment of the present invention, the first separator 1, the frame 3, and the second separator 2 arranged as shown in FIG. 1A are hot-pressed by the press 4 to form a frame. The first separator 1 and the second separator 2 are adhered on the main surfaces of both sides of 3.

In the present invention, the hot press can be carried out using, for example, a hot press machine. The conditions for the hot press are not particularly limited, and can be appropriately set according to the type of the thermoplastic resin that contributes to the adhesion constituting the frame, the rigidity of the frame, and the like. For example, the temperature can be in the range of 140 to 200 ° C. and the pressure can be in the range of 0.1 to 3.0 MPa.

As shown in FIG. 1 (b), in the first embodiment of the present invention, since the top of the rib provided in the separator has a rectangular parallelepiped concave portion, the frame and the separator can be adhered to each other. By heat pressing, the thermoplastic resin layer 3a constituting the frame 3 flows into both the recesses 1b and 1d of the rib of the first separator 1 and between the rib 1a and the rib 1c by heating and pressurizing. ..

According to the method for manufacturing a fuel cell of the present invention, the molten thermoplastic resin flows into the recesses provided in the ribs of the separator, so that the excess thermoplastic resin flows into the flow path formed between the ribs. Invasion can be suppressed.

As a result, it is possible to prevent the cross-sectional area of the flow path from becoming smaller due to the thermoplastic resin, it is possible to sufficiently supply the reaction gas to the membrane electrode assembly, and the performance of the fuel cell can be maintained. ..

Further, since the thermoplastic resin tends to remain between the frame and the separator during hot pressing, the sealing performance of the fuel cell can be improved.

<< Second Embodiment >>
The method for manufacturing the fuel cell of the present invention according to the second embodiment will be described with reference to FIG.

FIG. 3A is a diagram showing a state in which the first separator 5 and the second separator 6 are arranged on both sides of the frame 7. FIG. 3B is a diagram showing a fuel cell obtained by hot-pressing and adhering a first separator 5, a frame 7, and a second separator 6 arranged in FIG. 3A.

In the method for manufacturing a fuel cell according to the second embodiment of the present invention, as shown in FIGS. 3 (a) and 3 (b), on the tops of ribs 5a, 5c and the like provided in the first separator 5. The same operation as that of the first embodiment is carried out except that the recesses 5b and 5d having a substantially semi-cylindrical shape are provided. Each part is as described above.

Also in the second embodiment, as in the first embodiment, the frame 7 is arranged at the peripheral portion of the membrane electrode assembly (not shown) which is a power generation element of the fuel cell. Subsequently, the first separator 5 and the second separator 6 are arranged on both sides of the frame 7 and the membrane electrode assembly (not shown) so as to sandwich them.

As in the first embodiment, the plurality of ribs (for example, ribs 5a and 1c) included in the first separator 5 and the plurality of ribs included in the second separator 6 have a frame 7 interposed therebetween. It is placed in a position that does not face each other. Therefore, the ribs included in the second separator 6 are not shown in FIGS. 3 (a) and 3 (b).

Subsequently, the first separator 5, the frame 7, and the second separator 6 arranged as shown in FIG. 3A are hot-pressed by the press 8, and the first separator 5 is placed on the main surfaces of both sides of the frame 7. Separator 5 and the second separator 6 are adhered to each other.

As shown in FIG. 3B, in the second embodiment of the present invention, since the semi-cylindrical recess is provided on the top of the rib provided by the separator, the frame and the separator are adhered to each other. By heating and pressurizing, the thermoplastic resin layer 3a constituting the frame 7 is formed into both the recesses 5b and 1d provided by the ribs of the first separator 5 and between the ribs 5a and 5c. It flows in.

1, 5, 10 First separator 1a, 1c, 5a, 5c, 10a, 10c Rib 1b, 1d, 5b, 5d Recesses 2, 6, 20 Second separator 3, 7, 30 Frame 3a, 3c, 7a, 7c, 30a, 30c Thermoplastic resin layer 3b, 7b, 30b Core layer 4, 8, 40 Press

Claims (1)

Placing the frame on the peripheral edge of the membrane electrode assembly and adhering the separator onto at least one main surface of the frame by hot pressing.
Including
The separator is provided with a plurality of ribs having recesses at the top on a surface facing the frame, and the frame is made of a thermoplastic resin at least a part of the surface thereof.
Thereby, the heat press allows the thermoplastic resin to penetrate into the recesses while adhering the ribs to the frame to form a flow path between the adjacent ribs.
How to manufacture a fuel cell.

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