JP2007305573A - Separator for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separator for a fuel cell which has an excellent strength and durability and of which the unit cells can be assembled easily. <P>SOLUTION: The separator for a fuel cell is composed of a conductive resin layer which is formed by an electrodeposition process to coat a metal base plate and a gasket, and the resin layer contains a conductive material. Thus, the separator includes high corrosion resistance and can improve greatly an assembling work of unit cells and has high strength since the metal base plate is used. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a separator for a fuel cell, and more particularly to a separator used between unit cells of a fuel cell in which a plurality of unit cells having electrodes arranged on both sides of a solid polymer electrolyte membrane are connected.

A fuel cell is simply a device that continuously supplies fuel (reducing agent) and oxygen or air (oxidant) from the outside, and reacts electrochemically to extract electrical energy. It is classified by type, use, etc. Recently, solid oxide fuel cells, molten carbonate fuel cells, phosphoric acid fuel cells, solid polymer electrolyte fuel cells, and alkaline aqueous fuel cells are mainly used depending on the type of electrolyte used. Generally, it is classified into five types.
These fuel cells use hydrogen gas generated from methane or the like as a fuel. Recently, a direct methanol fuel cell (hereinafter also referred to as DMFC) that directly uses an aqueous methanol solution as a fuel is also known. Yes.

In such a fuel cell, a polymer electrolyte membrane is sandwiched between two types of catalysts, and further, these members are sandwiched between a gas diffusion layer (GDL) and a separator, and the polymer electrolyte fuel cell is configured. (Hereinafter also referred to as PEFC) is attracting attention.
In this PEFC, in order to prevent leakage of supplied fuel gas and oxidant gas to the outside or to prevent mixing, a gasket material is arranged so as to sandwich a polymer electrolyte membrane around the electrode, These are sandwiched between separators (Patent Document 1).
As the separator, for example, a molded body using carbon and resin, or a metal material coated with a metal thin film having high corrosion resistance is used (Patent Document 2).
Japanese Patent Laid-Open No. 2005-191002 JP 2005-2411 A

However, the gasket material is a separate member from the separator, the polymer electrolyte membrane, and the electrode, and there is a problem that the workability of assembling the unit cell using these is poor.
In addition, a separator made of a molded product has a limit to thinning, and a separator coated with a noble metal thin film having a high corrosion resistance such as gold exposes the metal material in the cross section, and the metal substrate and the metal There was a problem that cracks were likely to occur at the interface with the thin film.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel cell separator that is excellent in strength and corrosion resistance and that allows easy assembly of unit cells.

In order to achieve such an object, the present invention includes a metal substrate, a conductive resin layer formed by electrodeposition so as to cover the metal substrate, and a gasket material, and the resin layer is electrically conductive. It was set as the structure containing a material.
As another aspect of the present invention, the gasket material is configured to include a shim portion that is a height adjusting member and a seal portion that is a gas leakage preventing member.
As another aspect of the present invention, the seal portions are arranged in a multiple manner.
As another aspect of the present invention, the metal substrate has a groove portion on at least one surface, and the gasket material is located in an outer region of the region where the groove portion is formed.

As another aspect of the present invention, the metal substrate has a plurality of through holes, and the gasket material is positioned in an outer region of the through hole forming region.
As another aspect of the present invention, the resin layer is interposed between the gasket material and the metal substrate.
As another aspect of the present invention, the resin layer is not interposed between the gasket material and the metal base, and the side end of the metal base is exposed.
As another aspect of the present invention, the metal substrate is made of any one of stainless steel, iron, iron nickel alloy, aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, and magnesium alloy. .
As another aspect of the present invention, the conductive material is configured to be at least one of carbon particles, carbon nanotubes, carbon nanofibers, carbon nanohorns, and corrosion-resistant metals.

  In the separator of the present invention, since the resin layer containing the conductive material is formed on the metal substrate by electrodeposition, for example, even if the metal substrate has a groove or a through hole, the entire surface is a resin layer. Since it is covered and exhibits high corrosion resistance, the gasket material is integrally provided, so that the assembly of the unit cell is greatly improved. Further, the use of a metal substrate provides high strength, and since no precious metal is used, the manufacturing cost can be kept low. Further, when a resin layer is interposed between the gasket material and the metal substrate, the corrosion resistance is further improved. On the other hand, when there is no resin layer between the gasket material and the metal substrate, the material cost for forming the resin layer by electrodeposition is reduced, the adhesion of the gasket material to the metal substrate is improved, and the metal substrate is made of a resin layer. It is possible to reduce the resistance and improve the power generation performance by leaving a portion not covered as a current collector. In addition, when the gasket material is composed of a shim portion which is a height adjusting member and a seal portion which is a gas leakage preventing member, the gas sealing performance in the unit cell is further improved and the unit cell can be easily assembled. It will be something.

Embodiments of the present invention will be described below with reference to the drawings.
[Separator]
FIG. 1 is a plan view showing an embodiment of a separator for a fuel cell according to the present invention, FIG. 2 is a cross-sectional view taken along line II of the separator shown in FIG. 1, and FIG. 3 is surrounded by a chain line in FIG. FIG. 4 is a sectional view taken along line II-II of the separator shown in FIG. 1, FIG. 5 is a sectional view taken along line III-III of the separator shown in FIG. 1, and FIG. 6 is shown in FIG. It is sectional drawing in the IV-IV line of a separator. 1 to 6, a separator 1 according to the present invention includes a metal base 2, a groove 3 formed on both sides of the metal base 2, and a resin formed by electrodeposition so as to cover both sides of the metal base 2. Layer 5 and gasket materials 8 and 9 (shown by hatching in FIG. 1). The resin layer 5 contains a conductive material, and the gasket materials 8 and 9 are located in a region outside the region 4 where the groove 3 is formed. Further, the separator 1 includes two fuel gas supply holes 6a and 6b and two oxidant gas supply holes 7a and 7b.

The material of the metal substrate 2 constituting the separator 1 is preferably a material having good electrical conductivity, desired strength, and good workability. For example, stainless steel, iron, iron-nickel alloy, aluminum, aluminum alloy, copper, A copper alloy, titanium, a titanium alloy, magnesium, a magnesium alloy, etc. are mentioned.
When the separator 1 is incorporated in a polymer electrolyte fuel cell, one of the grooves 3 of the metal substrate 2 serves as a fuel gas supply groove for supplying fuel gas to adjacent unit cells, and the other is This is an oxidant gas supply groove for supplying an oxidant gas to another adjacent unit cell. One of the groove portions 3 may be either a fuel gas supply groove portion or an oxidant gas supply groove portion, and the other may be a cooling water groove. In the example shown in FIG. 1, the groove 3 is formed so as to be connected to the two fuel gas supply holes 6 a and 6 b, and serves as a fuel gas supply groove. In addition, the separator of this invention may be provided with the groove part 3 only in one surface of the metal base | substrate 2. FIG.

The shape of the groove 3 is not particularly limited, and may be a meandering continuous shape, a comb shape, or the like, and the depth, width, and cross-sectional shape are not particularly limited. Further, the shape of the groove 3 may be different between the front and back of the metal base 2. In the example shown in FIGS. 2 and 3, the cross-sectional structure of the formation region 4 of the groove 3 is a wave shape, but the groove is carved on both surfaces of the plate-like metal substrate. May be.
The resin layer 5 that constitutes the separator 1 has conductivity and imparts corrosion resistance to the metal substrate 2. The resin layer 5 is formed by electrodeposition using an electrodeposition liquid in which a conductive material and a water-repellent material are dispersed in various anionic or cationic synthetic polymer resins having electrodeposition properties. It can be formed by curing.

Examples of the anionic synthetic polymer resin include acrylic resin, polyester resin, maleated oil resin, polybutadiene resin, epoxy resin, polyamide resin, polyimide resin, etc., and these can be used alone or as a mixture of any combination. Can be used. Moreover, you may use together said crosslinking | crosslinked resin, such as anionic synthetic polymer resin and a melamine resin, a phenol resin, and a urethane resin. On the other hand, examples of the cationic synthetic polymer resin include acrylic resin, epoxy resin, urethane resin, polybutadiene resin, polyamide resin, polyimide resin, and the like. These can be used alone or as a mixture of any combination. Can do. Moreover, you may use together said cationic synthetic polymer resin and crosslinkable resin, such as a polyester resin and a urethane resin.
Further, in order to impart tackiness to the above-described synthetic polymer resin having electrodeposition properties, a tackifier resin such as rosin, terpene, and petroleum resin may be added as necessary.

Such an electrodepositable synthetic polymer resin is subjected to electrodeposition in a state where it is neutralized with an alkaline or acidic substance and solubilized in water, or in an aqueous dispersion state. That is, the anionic synthetic polymer resin is neutralized with amines such as trimethylamine, diethylamine, dimethylethanolamine and diisopropanolamine, and inorganic alkalis such as ammonia and caustic potash. The cationic synthetic polymer resin is neutralized with an acid such as formic acid, acetic acid, propionic acid, or lactic acid. The neutralized water-soluble polymer resin is used in a state of being diluted in water as a water-dispersed type or a dissolved type.
The thickness of the resin layer 5 formed by electrodeposition can be in the range of 0.1 to 100 μm, preferably 3 to 30 μm. If the thickness of the resin layer 5 is less than 0.1 μm, good corrosion resistance may not be ensured due to the occurrence of pinholes, etc. If it exceeds 100 μm, the occurrence of cracks after drying and solidification, etc. Problems such as reduction and high cost occur, which is not preferable.

  Examples of the conductive material contained in the resin layer 5 include carbon materials such as carbon particles, carbon nanotubes, carbon nanofibers, and carbon nanohorns, and corrosion-resistant metals. The conductive material is not limited to these conductive materials. In particular, fine fibrous carbon materials such as carbon nanotubes, carbon nanofibers, and carbon nanohorns are suitable for imparting conductivity to the resin layer 5. The content of such a conductive material in the resin layer 5 can be appropriately set according to the conductivity required for the resin layer 5, and can be set, for example, in the range of 30 to 90% by weight.

  Fine fibrous carbon materials such as carbon nanotubes, carbon nanofibers, and carbon nanohorns are expected to be applied to various fields such as composite materials and electronic devices as nanotechnology materials. When used as a composite material, the physical properties of these can be imparted to the composite material. For example, carbon nanotubes are excellent in terms of electrical conductivity, acid resistance, workability, mechanical strength, etc. When used as a filler in a composite material, the carbon nanotube has excellent physical properties. Can be granted.

  The gasket materials 8 and 9 constituting the separator 1 are members for preventing the supplied fuel gas and oxidant gas from leaking to the outside or mixing when the separator 1 is incorporated in the fuel cell. . Such gasket materials 8 and 9 are disposed on the peripheral edge so as to surround the center of the separator 1. In the example shown in FIGS. 1 to 6, the gasket material 8 is located in the region outside the region 4 where the groove 3 is formed, and is connected to the two fuel gas supply holes 6 a, 6 a, It is located outside the location of 6b. Accordingly, the two oxidant gas supply holes 7 a and 7 b are located in the formation region of the gasket material 8. On the other hand, on the opposite surface of the separator 1, the gasket material 9 is located in the region outside the region 4 where the groove 3 is formed and is supplied with two oxidant gases connected to the groove 3. Located outside the holes 7a, 7b. Therefore, the two fuel gas supply holes 6 a and 6 b are located in the formation region of the gasket material 9.

  Examples of the gasket materials 8 and 9 include rubber materials such as silicone rubber, fluorine rubber, and nitrile rubber, and materials obtained by coating the above rubber on resin materials such as olefin resins and polyethylene terephthalate. Moreover, the thickness of the gasket materials 8 and 9 can be appropriately set in consideration of the thickness of a membrane electrode assembly (MEA) as will be described later. For example, the thickness can be set in the range of 50 to 500 μm. The widths of the portions 8 and 9 can be set as appropriate, for example, at 1 mm or more.

  In the separator of the present invention, the gasket materials 8 and 9 may be composed of a shim portion that is a height adjusting member and a seal portion that is a gas leakage prevention member. In this case, the seal portions are arranged in multiple layers. Also good. FIG. 7 is a view showing such an example, and is a partially enlarged plan view of a portion surrounded by a chain line in FIG. In the example shown in FIG. 7, the gasket material 8 has double seal portions (portions hatched in FIG. 7) of an outer seal portion 8 a and an inner seal portion 8 b, and these seal portions 8 a, A shim portion 8c (a portion indicated by a one-dot chain line in FIG. 7) is disposed in the middle of 8b. As described above, the gasket materials 8 and 9 have a structure including the shim portion 8c which is a height adjusting member and the seal portions 8a and 8b which are gas leakage preventing members, so that the separator 1 is a polymer electrolyte fuel cell. The hermeticity when incorporated in the is improved. Moreover, the sealing performance is further improved by providing multiple seal portions. 7 shows an example in which the metal base 2 and the resin layer 5 exist to the outside of the seal portion 8a, so that the structure of the peripheral portion is different from the examples shown in FIGS. 2 and 4-6. It has become.

The materials of the seal portions 8a and 8b and the shim portion 8c may be the materials described in the description of the gasket materials 8 and 9. The material of the seal portions 8a and 8b and the material of the shim portion 8c may be different. In this case, it is preferable that the hardness of the seal portions 8a and 8b is set to be lower than the hardness of the shim portion 8c.
The thicknesses of the seal portions 8a and 8b and the shim portion 8c can be appropriately set in consideration of the thickness of the membrane electrode assembly (MEA) as will be described later. For example, the thickness is set in the range of 50 to 500 μm. Can do. Further, the thickness of the seal portions 8a and 8b may be different from the thickness of the shim portion 8c. In this case, it is preferable to set the thickness of the seal portions 8a and 8b to be larger than the thickness of the shim portion 8c. . In addition, the width of the seal portions 8a and 8b can be appropriately set, for example, at 0.3 mm or more, and the width of the shim portion 8c can be appropriately set, for example, at 0.3 mm or more.

FIG. 8 is a plan view showing another embodiment of the separator for a fuel cell of the present invention, and FIG. 9 is an enlarged partial sectional view taken along line VV of the separator shown in FIG. 8 and 9, the separator 11 of the present invention has a metal substrate 12, a plurality of through holes 13 formed in the metal substrate 12, and both surfaces of the metal substrate 12 including the inner wall surfaces of these through holes 13. The resin layer 15 is formed by electrodeposition so as to be covered, and the gasket materials 18 and 19 (shown by hatching in FIG. 8) are integrally provided. The resin layer 15 contains a conductive material, and the gasket materials 18 and 19 are located in an outer region of the through hole 13 formation region 14.
The metal substrate 12 constituting the separator 11 can be made of the same material as the metal substrate 2 constituting the separator 1 described above.

Further, the through hole 13 provided in the metal base 12 serves as a flow path for supplying fuel gas or oxidant gas to the unit cell when the separator 11 is incorporated into the fuel cell. There is no restriction | limiting in particular in the magnitude | size, the number of such a through-hole 13, and arrangement | positioning density.
The resin layer 15 constituting the separator 11 has conductivity and imparts corrosion resistance to the metal substrate 12. The resin layer 15 is formed by electrodeposition using an electrodeposition liquid in which a conductive material is dispersed in various anionic or cationic synthetic polymer resins having electrodeposition properties, and then cured to form. can do.

As the anionic synthetic polymer resin and the cationic synthetic polymer resin, the synthetic polymer resins mentioned in the description of the resin layer 5 can be used, and a combination with a crosslinkable resin is also possible. Further, in order to impart tackiness to the synthetic polymer resin having electrodeposition, a tackifier resin such as rosin, terpene, and petroleum resin may be added as necessary. Similarly to the electrodeposition formation of the resin layer 5 described above, the electrodepositable synthetic polymer resin can be electrodeposited in a state in which it is neutralized with an alkaline or acidic substance and solubilized in water, or in an aqueous dispersion state. Provided.
The resin layer 15 formed by electrodeposition has a thickness of 0.1 to 100 μm, preferably 3 to 30 μm. If the thickness of the resin layer 15 is less than 0.1 μm, good corrosion resistance may not be ensured due to the occurrence of pinholes, etc. If it exceeds 100 μm, the occurrence of cracks after drying and solidification, etc. Problems such as reduction and high cost occur, which is not preferable.

As the conductive material contained in the resin layer 15, those listed as the conductive material contained in the resin layer 5 can be used, and the content of the conductive material in the resin layer 15 is required for the resin layer 15. It can set suitably according to the electroconductivity which can be set, for example, can be set in 30-90 weight%.
The gasket materials 18 and 19 constituting the separator 11 are members for preventing the supplied fuel gas and oxidant gas from leaking to the outside or mixing when the separator 11 is incorporated in the fuel cell. It is. Such gasket materials 18 and 19 are disposed at the peripheral edge so as to surround the central portion of the separator 11, and are located in the outer region of the formation region of the through hole 13 in the illustrated example. The materials of the gasket materials 18 and 19 can be those mentioned in the description of the gasket materials 8 and 9, and the thickness and width of the gasket materials 18 and 19 are the same as those of the gasket materials 8 and 9 described above. It can be set similarly.

  Further, the gasket materials 18 and 19 may be composed of a shim portion which is a height adjusting member and a seal portion which is a gas leakage preventing member, in the same manner as the gasket materials 8 and 9 described above. As shown in FIG. 7, multiple seal portions may be provided. The material of the seal part and the shim part can be the same as that of the gasket materials 8 and 9, and the thickness and width of the seal part and the shim part are the same as those of the gasket materials 8 and 9. Can be set.

  The above-described embodiments of the separator of the present invention are examples, and the present invention is not limited to these embodiments. For example, the separator of the present invention may be one in which the gasket material is disposed only on one surface. Further, the gasket materials 8 and 9 and the gasket materials 18 and 19 may be directly disposed on the metal bases 2 and 12 without the resin layers 5 and 15 interposed therebetween. For example, as shown in FIG. 10, the separator 1 is provided with gasket materials 8 and 9 directly on the metal base 2 without the resin layer 5 interposed therebetween, and the resin layer 5 is formed only in the formation region 4 of the groove 3. It may be formed and the side end 2a of the metal substrate 2 may be exposed. Further, for example, as shown in FIG. 11, the separator 11 is provided with gasket materials 18 and 19 directly on the metal base 12 without the resin layer 15 interposed therebetween, and the resin layer 15 is a region where the through holes 13 are formed. 14, and the side end 12 a of the metal base 12 may be exposed.

  Since such separators 1 and 11 only need to form the resin layers 5 and 15 by electrodeposition only in the regions where the corrosion resistance is required (the formation region 4 of the groove 3 and the formation region 14 of the through hole 13), the material cost is reduced. Reduction is possible. Further, the adhesion of the gasket materials 8 and 9 and the gasket materials 18 and 19 to the metal bases 2 and 12 is high. Furthermore, by forming the resin layers 5 and 15 only in the region contributing to the power generation of the fuel cell, it can be distinguished from the region not contributing to the power generation (the region where the gasket materials 8 and 9 and the gasket materials 18 and 19 are located). The portions where the metal bases 2 and 12 are not covered with the resin layers 5 and 15 (side end portions 2a and 12a of the metal bases 2 and 12) function as current collectors (terminals). As compared with the case of using 15, a reduction in resistance is achieved, and the power generation performance can be improved. In the present invention, in addition to the side end portions 2a and 12a, the surfaces of the metal bases 2 and 12 in the region where the gasket materials 8 and 9 and the gasket materials 18 and 19 are formed, or In addition, a portion not covered with the resin layers 5 and 15 may exist on the outside thereof. Further, in the illustrated example, the conductive resin layer 5 does not exist between the gasket materials 8 and 9 and the metal base 2, but the resin layer 5 continuously extends from the formation region 4 of the groove 3 to the metal base 2. It may be slightly inserted between the gasket materials 8 and 9. Similarly, in the separator 11, the conductive resin layer 15 may slightly enter between the metal base 12 and the gasket materials 18 and 19.

[Example of separator production]
FIG. 12 is a view for explaining a manufacturing example of the separator 1 of the present invention shown in FIGS. In FIG. 12, a metal plate material is pressed to obtain a metal substrate 2 having grooves 3 on both sides (FIG. 12A). In addition to the above-described pressing, the metal substrate 2 is produced by, for example, forming a resist with a desired pattern by photolithography on both surfaces of the metal plate material, and etching the metal plate material from both surfaces using the resist as a mask. 3 may be used.
Next, the resin layer 5 is formed on both surfaces of the metal substrate 2 (FIG. 12B). The resin layer 5 is formed by electrodeposition using an electrodeposition liquid in which a conductive material is dispersed in various anionic or cationic synthetic polymer resins having electrodeposition properties, and then cured. Can be formed. The resin layer 5 formed in this way has good conductivity and high corrosion resistance.

Next, gasket materials 8 and 9 are formed at predetermined portions on both surfaces of the metal substrate 2 to obtain the separator 1 of the present invention (FIG. 12C). The gasket materials 8 and 9 are formed by, for example, a method of laminating and curing a film-like material processed into a desired shape, a method of printing and curing in a desired shape by a printing method such as screen printing, and a desired shape with a dispenser. It can carry out by the method of apply | coating to and hardening.
In addition, as shown in FIG. 7, when the gasket material is composed of seal portions 8a and 8b that are gas leakage prevention members and shim portions 8c that are height adjustment members, for example, a film processed into a desired shape The seal portions 8a and 8b can be formed by pasting and curing the material to form the shim portion 8c, and then applying and curing with a dispenser.

FIG. 13 is a diagram for explaining a manufacturing example of the separator 11 shown in FIGS. In FIG. 13, resists R and R are formed in a desired pattern on both surfaces of a metal plate 12 'by photolithography (FIG. 13A). The resists R, R have a plurality of openings, and the openings are positioned so as to face each other with the metal plate 12 'interposed therebetween. Next, using the resists R and R as a mask, the metal plate 12 'is etched from both sides to form a plurality of through holes 13, and then the resists R and R are peeled off to obtain the metal substrate 12 (FIG. 13B). ).
The through-hole 13 can be formed by a sandblasting method, a laser processing method, a drilling method, or the like in addition to the above-described etching method.

Next, the resin layer 15 is formed on the metal substrate 12 including the inner wall surface of the through hole 13 (FIG. 13C). The resin layer 15 can be formed in the same manner as the resin layer 5 described above.
Next, gasket materials 18 and 19 are formed at predetermined portions on both surfaces of the metal substrate 12 to obtain the separator 11 of the present invention (FIG. 13D). The gasket materials 18 and 19 can be formed in the same manner as the gasket materials 8 and 9 described above.

Moreover, FIG. 14 is a figure for demonstrating the manufacture example of the separator 11 shown by FIG. In FIG. 14, a metal substrate 12 having a plurality of through holes 13 is obtained in the same manner as described above with reference to FIGS. 13A and 13B (FIG. 14A).
Next, an insulating pattern R ′ is formed on the portions where the gasket materials 18 and 19 are formed on both surfaces of the metal base 12 and on the side end portion 12a (FIG. 14B).
Next, using the insulating pattern R ′ as a mask, the resin layer 15 is formed on the metal substrate 12 including the inner wall surface of the through hole 13, and then the insulating pattern R ′ is removed (FIG. 14C). The resin layer 15 can be formed in the same manner as the resin layer 5 described above. Note that without forming the insulating pattern R ′, an insulating jig is pressure-bonded to the portions where the gasket materials 18 and 19 on both sides of the metal substrate 12 are formed and to the side end portion 12a. The resin layer 15 may be formed by, and then the jig may be removed.

Next, gasket materials 18 and 19 are formed at predetermined portions where the resin layers 15 on both surfaces of the metal substrate 12 are not formed, and the separator 11 of the present invention is obtained (FIG. 14D). The gasket materials 18 and 19 can be formed in the same manner as the gasket materials 8 and 9 described above.
The above production examples are illustrative, and the production of the separator of the present invention is not limited to these examples.
[Example of fuel cell using separator of the present invention]

Here, an example of a polymer electrolyte fuel cell using the separator of the present invention will be described with reference to FIGS. FIG. 15 is a partial configuration diagram for explaining the structure of the polymer electrolyte fuel cell, and FIG. 16 is a diagram for explaining the membrane electrode assembly constituting the polymer electrolyte fuel cell. FIG. 18 is a perspective view showing the state in which the separator of the polymer electrolyte fuel cell and the membrane electrode assembly are separated from different directions.
15 to 18, a polymer electrolyte fuel cell 21 is a stack in which a plurality of unit cells are stacked by alternately stacking membrane electrode assemblies (MEA) 31 and separators 41. It has a structure.

  As shown in FIG. 16, the MEA 31 includes a fuel electrode (hydrogen electrode) 35 including a catalyst layer 33 and a gas diffusion layer (GDL) 34 disposed on one surface of the polymer electrolyte membrane 32. And an air electrode (oxygen electrode) 38 composed of a catalyst layer 36 and a gas diffusion layer (GDL) 37 disposed on the other surface of the polymer electrolyte membrane 32. Two fuel gas supply holes 46a and 46b and two oxidant gas supply holes 47a and 47b are formed as through holes at predetermined positions of the polymer electrolyte membrane 32.

The separator 41 is a separator according to the present invention, and includes a fuel gas supply groove 43a on one surface and an oxidant gas supply groove 43b on the other surface. Further, the surface on which the fuel gas supply groove 43a is formed is provided with a gasket material 48 located outside the formation region of the groove 43a and outside the two fuel gas supply holes 46a and 46b. (See FIG. 17). Further, the gasket material 49 located on the surface where the oxidant gas supply groove 43b is formed is located outside the formation region of the groove 43b and outside the two oxidant gas supply holes 47a and 47b. (See FIG. 18).
The separator 41 provided with the fuel gas supply groove 43a and the oxidant gas supply groove 43b has the resin layer 5 as shown in FIG. 3 formed on both surfaces of the metal substrate. is doing.

  In the polymer electrolyte fuel cell 21, the fuel electrode (hydrogen electrode) 35 of the MEA 31 is in contact with the surface of the separator 41 where the fuel gas supply groove 43 a is formed, and the oxidant gas supply groove 43 b of the separator 41. Each separator 41 and the MEA 31 are stacked so that the air electrode (oxygen electrode) 38 of the MEA 31 is in contact with the surface where the MEA 31 is formed, and the polymer electrolyte fuel cell 21 is configured by repeating this.

In the stacked state, the two fuel gas supply holes 46a and 46b form fuel gas supply paths penetrating in the stacking direction, and the two oxidant gas supply holes 47a and 47b are respectively An oxidant gas supply path that penetrates the lamination method is formed. In addition, the MEA 31 is sandwiched between the gasket materials 48 and 49 disposed in the separator 41 in an airtight state.
A separator of the present invention having a groove for cooling water on one surface and a groove for fuel gas supply 43a or an groove for supplying oxidant gas 43b on the other surface is interposed. A polymer electrolyte fuel cell equipped with a cooling mechanism may be provided by providing a cooling water supply hole in the molecular electrolyte membrane.

  Another example of the polymer electrolyte fuel cell using the separator of the present invention will be described with reference to FIGS. 19 is a plan view for explaining the structure of the polymer electrolyte fuel cell, and FIG. 20 is a longitudinal sectional view taken along line AA of the polymer electrolyte fuel cell shown in FIG. FIG. 2 is a view for explaining a membrane electrode assembly constituting a polymer electrolyte fuel cell.

  As shown in FIGS. 19 and 20, the polymer electrolyte fuel cell 51 includes a plurality of unit cells 52 each including a membrane-electrode assembly (MEA) 61 and separators 71A and 71B in a planar shape. These are polymer electrolyte fuel cells that are arranged and electrically connected in series to extract voltages corresponding to the number of unit cells (four in FIG. 19). Further, around each unit cell 52, an insulating portion 55 having substantially the same thickness as this is provided, and the whole is flat. That is, the unit cell 52 and the insulating part 55 are provided in a planar shape by fitting the unit cell 52 into the cut-out part of the flat insulating part 55.

  The polymer electrolyte fuel cell 51 is provided with a front and back connection part 57c for penetrating through the insulating part 55 located between adjacent unit cells of the insulating part 55 and connecting the front and back thereof. Then, the front / back connection portion 57c is connected to the separator 71A (for example, the fuel electrode side separator) of one adjacent unit cell via the connection wiring 57a, and the other adjacent one is connected via the connection wiring 57b. The unit cell is connected to a separator 71B (for example, an air electrode side separator). Thereby, adjacent unit cells are electrically connected in series. Wirings 75 and 76 are connected to the separator 71A of the unit cell 52 located at one end connected in series and the separator 71B of the unit cell 52 located at the other end.

In the illustrated example, the number of unit cells is four, but the number of unit cells is not limited.
The insulating part 55 insulates adjacent unit cells from each other except that they are connected by connection parts 57 (connection wirings 57a and 57b and front and back connection parts 57c). The material of the insulating part 55 is not particularly limited as long as it is excellent in terms of processability and durability. For example, glass epoxy, polyimide resin, or the like is used. The insulating portion 55 may be made of only an insulating material or may include a part of a conductive material.

As the front and back connection part 57c of the connection part 57, either a through-hole connection part or a filling via connection part or a bump connection part is provided in the insulating part 55 located between adjacent unit cells. it can. These front and back connection portions 57c can be formed as an application of conventional wiring board technology.
Further, as shown in FIG. 21, the MEA 61 includes a fuel electrode (hydrogen electrode) composed of a catalyst layer 63 and a gas diffusion layer (GDL) 64 disposed on one surface of the polymer electrolyte membrane 62. ) 65, and an air electrode (oxygen electrode) 68 including a catalyst layer 66 and a gas diffusion layer (GDL) 67 disposed on the other surface of the polymer electrolyte membrane 62.
The separators 71A and 71B are separators according to the present invention as shown in FIGS. 8 and 9, each having a conductive resin layer on a metal substrate having a plurality of through holes, and an outer region of the through hole forming region. Are integrally provided with gasket materials 72A and 72B.
The examples of the fuel cell described above are examples, and the fuel cell using the separator of the present invention is not limited to these examples.

Next, the present invention will be described in more detail by showing specific examples.
[Example 1]
As the metal plate material, SUS304 (80 mm × 80 mm) having a thickness of 0.8 mm was prepared, and the surface was degreased.
Next, this SUS304 was pressed to produce a metal substrate having a groove as shown in FIGS. The groove portion of this metal substrate had 70 groove portions with a width of 800 μm and a length of 80 mm alternately on the front and back at a pitch of 1200 μm, and the depth of each groove portion was 600 μm.
Next, the metal substrate was pretreated with an aqueous hydrochloric acid solution at 50 ° C. (1 part of 35% hydrochloric acid was added to 9 parts of water) and washed with water.

Subsequently, carbon black (Vulcan XC-72 manufactured by Cabot Co., Ltd.) as a conductive material was added to and dispersed in the epoxy electrodeposition liquid by 75% by weight with respect to the resin solid content to obtain an electrodeposition liquid.
The electrodeposition solution was stirred at 20 ° C., the metal substrate was immersed in the electrodeposition solution, electrodeposition was performed at a gap of 40 mm and a voltage of 50 V for 1 minute, and the pulled metal substrate was washed with pure water, and then dried. And dried with hot air (150 ° C., 3 minutes), and further subjected to heat treatment at 180 ° C. for 1 hour in a nitrogen atmosphere. Thereby, a resin layer having a thickness of 15 μm was formed so as to cover the metal substrate.

  Next, a laminated film in which an olefin-based resin (manufactured by ThreeBond Co., Ltd.) was coated on a polyethylene terephthalate film having a thickness of 0.25 mm by a die coating method was formed for shim formation. The laminated film is processed into a mold as shown in FIG. 1 and FIG. 7, and the laminated film after processing is bonded onto the resin layers on both sides of the metal substrate. A 200 μm gap was provided in the inner part and the outer part of the laminated film, and a fluororesin (manufactured by ThreeBond Co., Ltd.) was applied with a dispenser. Thereafter, heat treatment was performed at 180 ° C. for 1 hour. As a result, a shim portion (thickness: 300 μm) and a double seal portion having a width of 400 μm and a thickness of 350 μm were formed inside and outside the shim portion to obtain the separator of the present invention.

The above-mentioned epoxy electrodeposition solution was prepared as follows.
First, 1000 parts by weight of diglycidyl ether of bisphenol A (epoxy equivalent 910) was dissolved in 463 parts by weight of ethylene glycol monoethyl ether while maintaining the temperature at 70 ° C. with stirring, and further 80.3 parts by weight of diethylamine was added to 100 parts. An amine epoxy adduct (A) was prepared by reacting at 2 ° C. for 2 hours.
Coronate L (manufactured by Nippon Polyurethane Co., Ltd. diisocyanate: NCO 13% non-volatile content 75% by weight) 875 parts by weight dibutyltin laurate 0.05 parts by weight and heated to 50 ° C., to this, 390 weights of 2-ethylhexanol After that, the mixture was reacted at 120 ° C. for 90 minutes. A component (B) obtained by diluting the obtained reaction product with 130 parts by weight of ethylene glycol monoethyl ether was obtained.
Next, the mixture consisting of 1000 parts by weight of the above-described amine epoxy adduct (A) and 400 parts by weight of component (B) is neutralized with 30 parts by weight of glacial acetic acid, and then diluted with 570 parts by weight of deionized water. A resin A having a nonvolatile content of 50% by weight was prepared. An epoxy electrodeposition solution was prepared by blending 200.2 parts by weight of this resin A (resin component 86.3 volumes), 583.3 parts by weight of deionized water, and 2.4 parts by weight of dibutyltin laurate.

[Example 2]
An aluminum alloy (A5052P) having a size of 80 mm × 80 mm and a thickness of 0.8 mm was prepared as a metal plate material, and the surface was degreased.
Next, a dry film resist (manufactured by Nichigo Morton Co., Ltd.) is laminated on both surfaces of the aluminum alloy to form a 35 μm-thick photosensitive resist layer, and then exposed through a photomask for forming a groove ( A resist was formed by irradiating with a 5 kW mercury lamp for 15 seconds) and developing (spraying a 2% aqueous sodium hydrogen carbonate solution at 30 ° C.).
Next, a ferric chloride aqueous solution heated to 45 ° C. was sprayed from both sides of the aluminum alloy through the resist, and half-etched to a predetermined depth. Thereafter, the resist was peeled off with a 5% aqueous sodium hydrogen carbonate solution at 50 ° C. and subjected to a cleaning treatment. As a result, a metal substrate having a substantially semicircular cross section having a width of 1 mm and a depth of 0.3 mm, and a groove portion having a length of 1300 mm meandering with a deflection width of 50 mm and a pitch of 2 mm was obtained.

Next, pretreatment (passivation film removal) was performed on the metal substrate using an aqueous nitric acid solution, followed by washing with water.
Next, a zinc alloy treatment (thickness 0.05 μm) was formed on the metal substrate including the groove portion by subjecting the metal substrate to a zinc substitution treatment under the following conditions.
(Conditions for zinc replacement treatment)
・ Use bath: Zincate bath (Mertex Co., Ltd. ALMON EN)
・ Liquid temperature: 30 ℃
・ Processing time: 20 seconds

Next, a resin layer having a thickness of 15 μm was formed on the zinc alloy layer in the same manner as in Example 1.
Next, similarly to Example 1, a laminated film for forming a shim portion was produced, and this laminated film was die-molded into a frame shape so as to be located outside the groove forming region. The laminated film after processing is bonded onto the resin layers on both sides of the metal substrate, and then a gap of 200 μm is provided in the inner part and the outer part of the laminated film for the shim part, and a dispenser is used. A fluororesin (manufactured by Three Bond Co., Ltd.) was applied. Thereafter, heat treatment was performed at 180 ° C. for 1 hour. Thus, a shim part (thickness 300 μm) and a double seal part having a width of 400 μm and a thickness of 350 μm were formed inside and outside the shim part to obtain the separator of the present invention.

[Example 3]
A copper alloy (copper-tin-chromium alloy) having a size of 80 mm × 80 mm and a thickness of 0.8 mm was prepared as a metal plate, and the surface was degreased.
Next, a photosensitive material (a mixture of casein and ammonium dichromate) is applied to both surfaces of the copper alloy by a dip coating method to form a coating film having a thickness of 2 μm, and exposed through a photomask for groove formation. (Irradiated with a 5 kW mercury lamp for 60 seconds) and developed (sprayed with 40 ° C. hot water) to form a resist.
Next, a ferric chloride aqueous solution heated to 70 ° C. was sprayed from both sides of the copper alloy through the resist, and half-etched to a predetermined depth. Thereafter, the resist was peeled off with an aqueous caustic soda solution at 80 ° C. and subjected to a cleaning treatment. As a result, a metal substrate having a substantially semicircular cross section having a width of 1 mm and a depth of 0.3 mm, and a groove portion having a length of 1300 mm meandering with a deflection width of 50 mm and a pitch of 2 mm was obtained.

Next, the metal substrate was pretreated with 60 ° C. sulfuric acid (5 parts of water added to 1 part of sulfuric acid) and washed with water.
Next, a resin layer having a thickness of 15 μm was formed on the metal substrate in the same manner as in Example 1.
Next, similarly to Example 1, a laminated film for forming a shim portion was produced, and this laminated film was die-molded into a frame shape so as to be located outside the groove forming region. The laminated film after processing is bonded onto the resin layers on both sides of the metal substrate, and then a gap of 200 μm is provided in the inner part and the outer part of the laminated film for the shim part, and a dispenser is used. An olefin resin (manufactured by Three Bond Co., Ltd.) was applied. Thereafter, heat treatment was performed at 180 ° C. for 1 hour. Thus, a shim part (thickness 300 μm) and a double seal part having a width of 400 μm and a thickness of 350 μm were formed inside and outside the shim part to obtain the separator of the present invention.

[Example 4]
In the same manner as in Example 2, a groove was formed in an aluminum alloy (80 mm × 80 mm) having a thickness of 0.8 mm as a metal plate material to obtain a metal substrate.
Next, pretreatment and zinc substitution treatment were performed on the metal substrate in the same manner as in Example 2. Thereafter, the periphery of the metal substrate was crimped and sandwiched in a frame shape with a width of 3 mm from the side edge portion with a jig made of insulating rubber, and then a resin layer having a thickness of 15 μm was formed in the same manner as in Example 1. The resin layer formed in this way was present only in a portion not sandwiched by the above-mentioned insulating rubber jig.

  Next, similarly to Example 1, a laminated film for forming a shim portion was produced, and this laminated film was die-molded into a frame shape so as to be located outside the region where the resin layer was formed. The laminated film after processing is directly bonded to both surfaces of the metal substrate. Next, a gap of 200 μm is provided on the inner part and the outer part of the shim part laminated film, and an olefin resin ( Three Bond Co., Ltd.) was applied. Thereafter, heat treatment was performed at 180 ° C. for 1 hour. Thus, a shim part (thickness 300 μm) and a double seal part having a width of 400 μm and a thickness of 350 μm were formed inside and outside the shim part to obtain the separator of the present invention. In this separator, the metal substrate was exposed at the side end portion, the boundary portion between the shim portion and the seal portion, and the outer portion of the gasket material composed of the shim portion and the seal portion.

  The present invention can be applied to the manufacture of a fuel cell in which a plurality of unit cells each having an electrode disposed on both sides of a solid polymer electrolyte membrane are connected.

It is a top view which shows one Embodiment of the separator for fuel cells of this invention. It is sectional drawing in the II line of the separator shown by FIG. It is the elements on larger scale of the site | part enclosed with the chain line of FIG. It is sectional drawing in the II-II line of the separator shown by FIG. It is sectional drawing in the III-III line of the separator shown by FIG. It is sectional drawing in the IV-IV line of the separator shown by FIG. It is a figure which shows an example of a gasket member, and is the elements on larger scale of the site | part enclosed by the chain line of FIG. It is a top view which shows other embodiment of the separator for fuel cells of this invention. It is an expanded partial sectional view in the VV line of the separator shown by FIG. It is sectional drawing which shows other embodiment of the separator for fuel cells of this invention. It is sectional drawing which shows other embodiment of the separator for fuel cells of this invention. It is process drawing for demonstrating the manufacture example of the separator of this invention. It is process drawing for demonstrating the other manufacture example of the separator of this invention. It is process drawing for demonstrating the other manufacture example of the separator of this invention. It is a partial block diagram for demonstrating an example of the polymer electrolyte fuel cell using the separator of this invention. It is a figure for demonstrating the membrane electrode assembly which comprises the polymer electrolyte fuel cell shown by FIG. FIG. 16 is a perspective view showing a state where the separator and the membrane electrode assembly of the polymer electrolyte fuel cell shown in FIG. 15 are separated from each other. FIG. 18 is a perspective view showing a state where the separator and the membrane electrode assembly of the polymer electrolyte fuel cell shown in FIG. 15 are separated from a direction different from FIG. 17. It is a top view for demonstrating the other example of the polymer electrolyte fuel cell using the separator of this invention. FIG. 20 is a longitudinal sectional view taken along line VI-VI of the polymer electrolyte fuel cell shown in FIG. 19. It is a figure for demonstrating the membrane electrode assembly which comprises the polymer electrolyte fuel cell shown by FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Separator 2 ... Metal base | substrate 2a ... Side edge part 3 ... Groove part 4 ... Groove part formation area 5 ... Resin layer 8, 9 ... Gasket material 8a, 8b ... Seal part 8c ... Shim part 11 ... Separator 12 ... Metal base | substrate 12a ... side End part 13 ... Through hole 14 ... Through hole forming region 15 ... Resin layer 18, 19 ... Gasket material 21,51 ... Polymer electrolyte fuel cell 31,61 ... Membrane electrode assembly (MEA)
41, 71A, 71B ... separators 48, 49, 72A, 72B ... gasket material

Claims (9)

  A fuel cell separator comprising: a metal substrate; a conductive resin layer formed by electrodeposition so as to cover the metal substrate; and a gasket material, wherein the resin layer contains a conductive material. .   2. The fuel cell separator according to claim 1, wherein the gasket material includes a shim portion that is a height adjusting member and a seal portion that is a gas leakage preventing member.   The separator for a fuel cell according to claim 2, wherein the seal portions are arranged in multiple.   The fuel cell according to any one of claims 1 to 3, wherein the metal base has a groove on at least one surface, and the gasket material is located in an outer region of the region where the groove is formed. Separator for use.   4. The fuel cell according to claim 1, wherein the metal substrate has a plurality of through holes, and the gasket material is located in an outer region of the through hole forming region. 5. Separator.   The fuel cell separator according to any one of claims 1 to 5, wherein the resin layer is interposed between the gasket material and the metal substrate.   The said resin layer is not interposed between the said gasket material and the said metal base | substrate, and the side edge part of a metal base | substrate is exposed, The Claim 1 thru | or 5 characterized by the above-mentioned. Separator for fuel cells.   The metal substrate is made of any one of stainless steel, iron, iron-nickel alloy, aluminum, aluminum alloy, copper, copper alloy, titanium, titanium alloy, magnesium, and magnesium alloy. The separator for fuel cells in any one.   The separator for a fuel cell according to any one of claims 1 to 8, wherein the conductive material is at least one of carbon particles, carbon nanotubes, carbon nanofibers, carbon nanohorns, and corrosion-resistant metals.

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