JP2022029313A - Fuel battery cell, fuel battery and manufacturing method for fuel battery cell - Google Patents

Abstract

To provide a flat fuel battery cell with a sealed gas diffusion layer.SOLUTION: A fuel battery cell, which is a membrane-electrode assembly formed by stacking a gas diffusion layer, a catalyst layer and a polymer electrolyte membrane, includes a membrane-electrode assembly formed with a gas non-transmission layer by resin impregnation at an outer-peripheral part of the gas diffusion layer and a cell frame joined to meet the gas non-transmission layer.SELECTED DRAWING: Figure 3B

Description

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

The fuel cell stack is assembled by stacking a separator and a fuel cell. Further, in order to achieve both a flow path structure for gas or cooling water and a seal structure for preventing fluid leakage, a method is known in which separators, cells, and seals are combined with steps.

The fuel cell is composed of a membrane electrode assembly (MEA) and a cell frame. The membrane electrode assembly has a laminated structure in the order of a cathode electrode membrane, an electrolyte membrane, and an anode electrode membrane. Further, the electrode membrane is composed of a gas diffusion layer and a catalyst layer. One of the methods for producing a fuel cell cell is a method in which an electrolyte membrane is exposed from a membrane electrode assembly and the cell frame is joined so as to wrap the electrolyte.

However, in this method, since the electrolyte membrane is soft, it takes time to join the cell frame, and the electrolyte membrane region that does not contribute to power generation is wasted. Further, when there is a step between the cell frame and the membrane electrode assembly, it is necessary to make a step on the separator between the portion corresponding to the cell frame and the portion corresponding to the membrane electrode assembly, which complicates the stack structure. It will be transformed.

Japanese Patent No. 6115414

An object to be solved by the present invention is to provide a flatter fuel cell in which a gas diffusion layer is sealed.

The fuel cell according to the embodiment is a membrane electrode assembly in which a gas diffusion layer, a catalyst layer, and a polymer electrolyte membrane are laminated, and a gas impermeable layer by impregnating the outer periphery of the gas diffusion layer with a resin. The membrane electrode assembly provided with the above and the cell frame to be joined corresponding to the gas impermeable layer are provided.

According to the present invention, a flatter fuel cell with a sealed gas diffusion layer can be produced.

A bird's-eye view showing the configuration of the fuel cell according to the first embodiment. FIG. 1 is a cross-sectional view taken along the line AA'in FIG. FIG. 1 is a cross-sectional view taken along the line BB'in FIG. FIG. 1 is a cross-sectional view taken along the line BB'in FIG. Top view of polymer electrolyte fuel cell. FIG. 3A is a cross-sectional view taken along the line AA'. The figure which shows typically about the impregnation method. The figure which shows typically the method of joining a cell frame. The figure which shows the example of the method of performing the resin impregnation treatment of a gas diffusion layer and the bonding of a cell frame at the same time.

Hereinafter, the fuel cell, the fuel cell, and the method for manufacturing the fuel cell according to the embodiment of the present invention will be described in detail with reference to the drawings. The embodiments shown below are examples of the embodiments of the present invention, and the present invention is not limited to these embodiments. Further, in the drawings referred to in the present embodiment, the same parts or parts having similar functions may be designated by the same reference numerals or similar reference numerals, and the repeated description thereof may be omitted. Further, the dimensional ratio of the drawing may differ from the actual ratio for convenience of explanation, or a part of the configuration may be omitted from the drawing.

FIG. 1 is a bird's-eye view showing the configuration of the fuel cell according to the present embodiment. The fuel cell 1 is, for example, a polymer electrolyte fuel cell, and is configured by stacking fuel cell unit cells 2. 2A is a cross-sectional view taken along the line AA'of FIG. 1, FIG. 2B is a cross-sectional view taken along the line BB'of FIG. 1, and FIG. 2C is a cross-sectional view taken along the line CC'of FIG.

As shown in FIG. 1, the fuel cell unit cell 2 generates electricity by using, for example, an oxygen-containing gas as an oxidant and, for example, a hydrogen-containing gas as a fuel. The fuel cell unit cell 2 has a fuel cell 10, a cathode separator 20, and an anode separator 30. That is, the fuel cell unit cell 2 has a structure in which the fuel cell 10, the cathode separator 20, and the anode separator 30 are laminated as a set. It is possible to stack a plurality of fuel cell unit cells 2. A structure in which a plurality of fuel cell unit cells 2 are stacked in series is called a fuel cell stack. Further, the fuel cell unit cell 2 may be referred to as a cell.

The fuel cell 10 is, for example, a polymer electrolyte fuel cell, and has a membrane electrode assembly (MEA) 100 and a cell frame 101. As shown in FIGS. 2A to 2C, the membrane electrode assembly 100 has an anode electrode 100a, a polymer electrolyte membrane 100b, and a cathode electrode 100c. The membrane electrode assembly 100 generates electricity by the fuel electrode reaction between the fuel and the oxidant. As shown in FIG. 1, the cell frame 101 is provided with oxidant manifolds 102a and b, refrigerant manifolds 104a and b, and fuel manifolds 106a and b. The cell frame 101 is made of a material that does not allow gas to pass through.

As described above, the fuel is, for example, a hydrogen-containing gas, but is not limited thereto. Further, as described above, the oxidizing agent is, for example, an oxygen-containing gas, but is not limited thereto. Furthermore, the refrigerant is, for example, water, but is not limited thereto.

As shown in FIG. 1 again, the cathode separator 20 is formed with an oxidant flow path 200, oxidant manifolds 102a and b, refrigerant manifolds 104a and b, and fuel manifolds 106a and b. Further, the cathode separator 20 is provided with a sealing material 202 on the cathode side. The cathode separator 20 is produced by pressing a metal thin film or injection molding a carbon material.

The oxidant flow path 200 is a flow path for flowing the oxidant. As shown in FIGS. 2A to 2C, the anode electrode 100a of the fuel cell 10 is in contact with the anode separator 30, and the cathode electrode 100c is in contact with the cathode separator 20. Further, the oxidant flow path 200 has a rib 200a and a groove portion 200b.

As shown in FIG. 2A, the oxidant introduced from the oxidant manifold 102a is discharged from the oxidant manifold 102b via the groove portion 200b of the oxidant flow path 200. In this way, the oxidizing agent is supplied to the cathode electrode 100c from the groove portion 200b of the oxidizing agent flow path 200.

The oxidant flow path 200 is sealed with a sealing material 202 so as not to leak the fluid to the outside. That is, the sealing material 202 is provided to prevent leakage of the oxidizing agent. As shown in FIG. 1, the sealing material 202 according to the present embodiment is formed on the cathode separator 20, but is not limited thereto. For example, the sealing material 202 may be formed on the fuel cell 10, or only the sealing material 202 may be formed like a gasket and installed between the fuel cell 10 and the cathode separator 20. May be good.

As shown in FIG. 1 again, on the surface of the anode separator 30 on the cathode separator 20 side, the refrigerant flow path 300 through which the refrigerant flows, the oxidant manifolds 102a and b, the refrigerant manifolds 104a and b, and the fuel manifolds 106a and b And are formed. Further, a sealing material 302 is provided on the surface of the anode separator 30 on the cathode separator 20 side. The anode separator 30 is produced by pressing a metal thin film or injection molding a carbon material.

The refrigerant flow path 300 is a flow path for flowing the refrigerant. As shown in FIG. 2B, the refrigerant flow path 300 has a rib 300a and a groove portion 300b. The refrigerant introduced from the refrigerant manifold 104a is discharged from the refrigerant manifold 104b via the groove portion 300b of the refrigerant flow path 300. In this way, the cathode separator 20 and the anode separator 30 are cooled by the refrigerant flowing through the groove portion 300b of the refrigerant flow path 300.

As shown in FIG. 2B, the refrigerant flow path 300 is sealed with a sealing material 302 so as not to leak the fluid to the outside. The sealing material 302 is formed between the cathode separator 20 and the anode separator 30. That is, the sealing material 302 is provided to prevent leakage of the refrigerant. The sealing material 302 according to the present embodiment is formed on the anode separator 30, but is not limited thereto. For example, the sealing material 302 may be formed on the cathode separator 20, or only the sealing material 302 may be prepared like a gasket and installed between the cathode separator 20 and the anode separator 30. good.

As shown in FIG. 2C, a fuel flow path 400 (see FIGS. 2A and 2B) through which fuel flows is formed on the surface of the anode separator 30 opposite to the cathode separator 20 side. Further, a sealing material 402 is provided on the surface of the anode separator 30 opposite to the cathode separator 20 side. The fuel introduced from the fuel manifold 106a (see FIGS. 2A to 2C) is discharged from the fuel manifold 106b via the groove portion 400b of the fuel flow path 400. In this way, fuel is supplied to the anode electrode 100a from the groove portion 400b of the fuel flow path 400.

As shown in FIG. 2C, the fuel flow path 400 is sealed with a sealing material 402 so as not to leak the fluid to the outside. The sealing material 402 is also formed between the fuel cell 10 and the anode separator 30. That is, the sealing material 402 is provided to prevent fuel leakage. The sealing material 402 according to the present embodiment is formed on the anode separator 30, but is not limited thereto. For example, the sealing material 402 may be formed on the fuel cell 10, or only the sealing material 402 may be created like a gasket and installed between the fuel cell 10 and the anode separator 30. You may.

In this way, the oxidant is supplied to the cathode electrode 100c from the groove 200b of the oxidant flow path 200, and fuel is supplied to the anode electrode 100a from the groove 400b of the fuel flow path 400. As a result, the membrane electrode assembly 100 generates electricity by the reaction represented by the chemical formula 1. That is, the oxygen-containing gas flows through the oxidant flow path 200 of the cathode electrode 100c and causes an oxidant electrode reaction. Further, the hydrogen-containing gas flows through the fuel flow path 400 on the anode electrode 100a side and causes a fuel electrode reaction.
[Chemical formula 1]
Fuel electrode reaction: 2H ₂ → 4H ⁺ + 4e ^－
Oxidizing agent pole reaction: O ₂ + 4H ⁺ + ^4e- → 4H ₂ O
The flow paths 200, 300, and 400 according to the present embodiment have a serpentine structure that bends several times in the middle, but the flow path 200, 300, and 400 are not limited to this.

FIG. 3A is a top view of the polymer electrolyte fuel cell 10. FIG. 3B is a cross-sectional view taken along the line AA'of FIG. 3A.

As shown in FIGS. 3A and 3B, the fuel cell 10 has a structure in which a cell frame 101 is provided on the outer periphery of the membrane electrode assembly 100. The cell frame 101 has, for example, a first cell frame 101a, a second cell frame 101b, and a second cell frame 101c. The anode electrode 100a has an anode-side gas diffusion layer 100d and an anode-side catalyst layer 100e. Similarly, the cathode electrode 100c has a cathode side gas diffusion layer 100f and a cathode side catalyst layer 100g.

As the above-mentioned polymer electrolyte membrane 100b, those generally used for solid polymer fuel cells may be used. For the polymer electrolyte membrane 100b, for example, a fluorine-based electrolyte membrane or a hydrocarbon electrolyte membrane is used.

For the gas diffusion layers 100d and 100f, for example, a material such as carbon paper that easily permeates gas and has conductivity is used. That is, the gas diffusion layers 100d and 100f may be those generally used for polymer electrolyte fuel cells.

The catalyst layers 100e and 100g may be those generally used for polymer electrolyte fuel cells. For example, fine particles (average grain size) of platinum or an alloy of platinum with other metals (eg ruthenium (Ru), rhodium (Rh), molybdenum (Mo), chromium (Cr), cobalt (Co), iron (Fe), etc.). Conductive carbon fine particles such as carbon black (preferably having an average particle size of about 20 to 100 nm) on which a diameter of 10 nm or less is supported on the surface and a polymer solution such as a perfluorosulfonic acid resin solution are formed. , Those made of catalytic ink uniformly mixed in a suitable solvent (such as ethanol) can be used.

The membrane electrode assembly 100 further has a first gas impermeable layer 108a and a second gas impermeable layer 108b. The first gas impermeable layer 108a is an impregnated region in which the outer peripheral portion of the anode-side gas diffusion layer 100d is impregnated with a resin. Similarly, the second gas impermeable layer 108b is an impregnated region in which the outer peripheral portion of the cathode side gas diffusion layer 100f is impregnated with a resin.

FIG. 4 is a diagram schematically showing the impregnation method. Above is a plan view of the membrane electrode assembly 100 before impregnation and an AA'cross section of the membrane electrode assembly 100, and a plan view of the membrane electrode assembly 100 after impregnation and an AA'cross section of the membrane electrode assembly 100. Shown in order from.

As shown in FIG. 4, a thermoplastic resin sheet 104 is superposed on the upper surface and the lower surface of the membrane electrode assembly 100 before impregnation and thermocompression bonded. As a result, the resin sheet 104 permeates the gas diffusion layers 100d and 100f. As described above, the first gas impermeable layer 108a impregnated with the resin on the outer peripheral portion of the anode side gas diffusion layer 100d and the second gas impermeable layer 108b impregnated with the resin on the outer peripheral portion of the cathode side gas diffusion layer 100f. And are formed. The first gas impermeable layer 108a and the second gas impermeable layer 108b, which are resin-impregnated portions, do not allow gas to permeate.

As the material of the sheet 104, mainly thermoplastic resins such as acrylic, urethane, polyethylene, polypropylene, polystyrene and polyvinyl acetate can be used. The gas diffusion layer may be impregnated with a resin first, and then the high electrolyte membrane 100b, the anode-side catalyst layer 100e, the cathode-side catalyst layer 100g, and the like may be bonded to form a membrane electrode assembly 100.

The joining method of the cell frame 101 will be described with reference to FIG. FIG. 5 is a diagram schematically showing a method of joining the cell frame 101. For example, a plastic film is used for the first cell frame 101a, the second cell frame 101b, and the third cell frame 101c. This makes it possible to easily configure the cell frame 101. Materials of plastic film include, for example, polyethylene, polypropylene, polyethylene terephthalate, polystyrene, polycarbonate, polyurethane, phenol resin, polyimide, polyamide, melamine resin, polyethylene naphthalate, polyacetal, ABS resin, polyether ethyl ketone, polyphenylene ether, poly. It is possible to use vinyl acetate, fluororesin and the like.

First, the second cell frame 101b and the third cell frame 101c are first generated from a plastic film. The first type of second cell frame 101b is a plastic film having substantially the same thickness as the membrane electrode assembly 100. The second cell frame 101b is formed by removing the inside of one plastic film so that the membrane electrode assembly 100 can be accommodated. The second type of third cell frame 101c is also generated by removing the inside of one plastic film. In this case, the inner plastic film having an area smaller than that of the second cell frame 101b is removed from the third cell frame 101c so that the third cell frame 101c can be bonded to the membrane electrode assembly 100. The first cell frame 101a and the third cell frame 101c are generated with a thickness of 50 μm or less so that the step after being bonded to the membrane electrode assembly 100 is as small as possible.

Then, the two-cell frame 101b and the third-cell frame 101c, which are these two types of plastic films, are bonded together with an adhesive. As the adhesive, acrylic, epoxy, polyethylene, polypropylene, polyester, polyolefin, urethane, polyvinyl acetate and the like can be used.

Next, as shown in (B), the membrane electrode assembly 100 is placed in the second cell frame 101b and the third cell frame 101c, which are bonded plastic films, and the second cell frame 101b is coated with an adhesive. , And the third cell frame 101c and the membrane electrode assembly 100 are bonded together. As the adhesive, acrylic, epoxy, polyethylene, polypropylene, polyester, polyolefin, urethane, polyvinyl acetate and the like can be used.

Next, as shown in (C), the first cell frame 101a, which is the third plastic film, is attached. The first cell frame 101a is a plastic film having the same shape as the third cell frame 101c, which is the second type of plastic film. The bonded portion is for the portion of the second cell frame 101b and the cell frame and the portion of the membrane electrode assembly 100. As the adhesive, acrylic, epoxy, polyethylene, polypropylene, polyester, polyolefin, urethane, polyvinyl acetate and the like can be used. The hollowed out portion of the manifold may be provided on a plastic film in advance, or may be hollowed out after the bonding is completed. As described above, it becomes easier to bond the first cell frame 101a and the third cell frame 101c having a thickness of 50 μm or less to the membrane electrode assembly 100, and the flatter fuel cell 10 becomes more flattened. It can be easily generated. Further, since the first gas impermeable layer 108a and the second gas impermeable layer 108b, which are the resin impregnated portions, do not allow gas to permeate, the gas diffusion layers 100d and 100f can be sealed.

FIG. 6 is a diagram showing an example of a method in which the resin impregnation treatment of the gas diffusion layers 100d and 100f and the bonding of the cell frame 101 are performed at the same time. The dimensions and materials of the plastic film can be the same as those shown in FIG.

As shown in (A), an adhesive is provided on the third cell frame 101c, and then, as shown in (B), the second cell frame 101b and the membrane electrode assembly 100 are placed. By simultaneously crimping these, the lower gas diffusion layer is impregnated with the resin of the adhesive, and at the same time, the second cell frame 101b and the third cell frame 101c, which are the plastic films of the cell frame, are also bonded. As the adhesive, acrylic, epoxy, polyethylene, polypropylene, polyester, polyolefin, urethane, polyvinyl acetate and the like can be used.

Next, an adhesive is attached to the first cell frame 101a, which is the upper plastic film, and the adhesive is overlapped with the membrane electrode assembly 100 and crimped. As shown in (C), the upper gas diffusion layer is impregnated with the adhesive resin, and at the same time, the cell frame 101 first cell frame 101a and the second cell frame 101b are also bonded. As the adhesive, acrylic, epoxy, polyethylene, polypropylene, polyester, polyolefin, urethane, polyvinyl acetate and the like can be used.

As described above, according to the present embodiment, the gas impermeable layers 108a and b by resin impregnation are provided on the outer peripheral portions of the gas diffusion layers 100d and 100f of the membrane electrode assembly 100, and the gas impermeable layers 108a and b are provided. It was decided to join the cell frame 101 in correspondence. This makes it possible to seal the gas diffusion layers 100d and 100f and to join the cell frame 101 more easily.

1: Fuel cell, 10: Fuel cell, 20: Cathode separator, 30: Anode separator, 100: Film electrode junction, 100a: Anode electrode, 100c: Cathode electrode, 100b: Polymer electrolyte membrane, 100d: Anode side gas Diffusion layer, 100f: Cathode gas diffusion layer, 101: Cell frame, 101a: First cell frame, 101b: Second cell frame, 101c: Third cell frame, 108a: First gas impermeable layer, 108b: Second Gas impermeable layer.

Claims (14)

A membrane electrode assembly in which a gas diffusion layer, a catalyst layer, and a polyelectrolyte film are laminated, and a membrane electrode assembly in which a gas impermeable layer by impregnation with a resin is provided on the outer peripheral portion of the gas diffusion layer. ,
The cell frame to be joined corresponding to the gas impermeable layer and
Equipped with a fuel cell. The fuel cell according to claim 1, wherein the cell frame is composed of a three-layer frame and is joined to the gas impermeable layer by the upper and lower layers. The fuel cell according to claim 2, wherein the three-layer frames are bonded to each other with an adhesive. The fuel cell according to claim 3, wherein the material for joining the upper and lower frames of the three-layer frame to the gas impermeable layer is the same material as the impregnated material by the resin impregnation. The fuel cell according to any one of claims 1 to 3, wherein the cell frame is a plastic film. The fuel cell according to any one of claims 1 to 5, wherein the material impregnated in the gas impermeable layer is at least one of acrylic, urethane, polyethylene, polypropylene, polystyrene, and polyvinyl acetate. cell. The material of the plastic film is polyethylene, polypropylene, polyethylene terephthalate, polystyrene, polycarbonate, polyurethane, phenol resin, polyimide, polyamide, melamine resin, polyethylene naphthalate, polyacetal, ABS resin, polyether ethyl ketone, polyphenylene ether, polyacetic acid. The fuel cell according to claim 5, which is at least one of vinyl and a fluororesin. The fuel cell according to any one of claims 1 to 7, wherein the fuel cell is a polymer electrolyte fuel cell. The fuel cell according to any one of claims 1 to 8 and the fuel cell.
An anode separator having a fuel flow path in contact with the anode electrode of the fuel cell,
A cathode separator having an oxidant flow path in contact with the cathode electrode of the fuel cell,
Equipped with a fuel cell. A step of arranging a sheet of a thermoplastic resin on the outer peripheral portion of the gas diffusion layer of a membrane electrode assembly in which a gas diffusion layer, a catalyst layer, and an electrolyte membrane are laminated.
A step of thermocompression bonding the sheet to the gas diffusion layer to form a gas impermeable layer in which the gas diffusion layer is impregnated with a resin.
A method of manufacturing a fuel cell. The step of joining the cell frame corresponding to the gas impermeable layer,
The method for manufacturing a fuel cell according to claim 10, further comprising. The method for manufacturing a fuel cell according to claim 11, wherein after the gas impermeable layer is generated, a step of joining the cell frame corresponding to the gas impermeable layer is performed. The method for manufacturing a fuel cell according to claim 11, wherein the step of forming the gas impermeable layer and the step of joining the cell frame corresponding to the gas impermeable layer are simultaneously performed. The method for manufacturing a fuel cell according to any one of claims 10 to 13, wherein the material of the sheet is at least one of acrylic, urethane, polyethylene, polypropylene, polystyrene, and polyvinyl acetate.

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