JP5082275B2 - Separator for fuel cell and manufacturing method thereof - Google Patents

Description

  The present invention relates to a separator for a fuel cell, and in particular, a separator used for each unit cell 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, and a method for producing such a separator. About.

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 fuel cell having a structure in which a solid polymer membrane is sandwiched between two types of catalyst and these members are sandwiched between a gas diffusion layer (GDL) and a separator. (Hereinafter also referred to as PEFC) is attracting attention.

In this PEFC, a unit structure in which an air electrode (oxygen electrode) and a fuel electrode (hydrogen electrode) are arranged on both sides of a solid polymer electrolyte membrane is stacked in order to obtain a desired electromotive force, Alternatively, a structure in which a plurality of planes are connected in series is employed. For example, in the case of the above-described stack structure, the separator disposed between the unit cells is formed with a fuel gas supply groove for supplying fuel gas to the adjacent unit cell on its side. An oxidant gas supply groove for supplying oxidant gas to the other adjacent unit cell is formed on the other surface.
As such a separator, a metal separator is preferable from the viewpoint of cost and strength, but there is a problem in corrosion resistance. For this reason, metal separators that have been provided with corrosion resistance by forming a conductive electrodeposition coating have been developed (Patent Documents 1, 2, and 3).
JP 2004-31166 A JP 2003-249240 A JP 2004-197225 A

However, in the case of the metal separator in which the electrodeposition coating film as described above is directly formed on the metal substrate, the passive film or oxide film is used as the metal substrate when a passive film or a substrate that easily generates an oxide film is used. There is a problem that the passive film and the oxide film are regenerated during the step of removing or during the cleaning and transportation after the removal, and the connection resistance between the metal substrate and the electrodeposition coating film is increased.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a separator for a fuel cell that is excellent in strength and corrosion resistance and has low connection resistance, and a method for manufacturing the same.

In order to achieve such an object, the separator of the present invention includes a metal base and a conductive resin layer formed by electrodeposition so as to cover the metal base via an intermediate layer, and the metal The substrate is made of copper or a copper alloy, the intermediate layer has a two-layer structure in which nickel and gold are laminated from the metal substrate side , and the resin layer contains a conductive material.
As another aspect of the present invention, the metal substrate is configured to have a groove on at least one surface.
As another aspect of the present invention, the metal substrate is configured to have a plurality of through holes.
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.

The method for producing a separator for a fuel cell according to the present invention comprises forming an intermediate layer by laminating nickel and gold in this order on a metal substrate made of copper or a copper alloy , and then forming an electrodeposition resin on the intermediate layer. A resin layer was formed by electrodeposition using an electrodeposition liquid in which a conductive material was dispersed.
As another aspect of the present invention, the intermediate layer is formed immediately after the passivation film or oxide film is removed from the metal substrate.

The separator of the present invention has at least one of nickel, palladium, platinum, copper, silver, gold, ruthenium, rubidium, zinc, lead, tin, or an alloy of these metals between the metal substrate and the conductive resin layer. Since the seed intermediate layer is interposed, the connection resistance between the metal substrate and the resin layer is small, the power generation capability of the fuel cell can be improved, and high strength and excellent corrosion resistance are provided.
Further, in the separator manufacturing method of the present invention, an intermediate layer is formed on the metal substrate before the conductive resin layer is formed by electrodeposition. Therefore, a metal substrate that easily generates a passive film or an oxide film is used. However, the formation and regeneration of the passive film or oxide film is blocked by the intermediate layer, and the connection resistance between the metal substrate and the resin layer becomes small.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Separator]
FIG. 1 is a partial sectional view showing an embodiment of a separator for a fuel cell of the present invention. In FIG. 1, a separator 1 of the present invention is formed by electrodeposition through a metal substrate 2, grooves 3 formed on both surfaces of the metal substrate 2, and an intermediate layer 4 so as to cover both surfaces of the metal substrate 2. The resin layer 5 contains a conductive material.
FIG. 2 is a partial sectional view showing another embodiment of the separator for a fuel cell of the present invention. In FIG. 2, the separator 11 of the present invention covers both surfaces of a metal substrate 12, a plurality of through holes 13 formed in the metal substrate 12, and the metal substrate 12 including the inner wall surfaces of these through holes 13. And the resin layer 15 formed by electrodeposition through the intermediate layer 14, and the resin layer 15 contains a conductive material.

The material of the metal bases 2 and 12 constituting the separators 1 and 11 is preferably a material having good electrical conductivity, desired strength, and good workability. For example, stainless steel, iron, iron-nickel alloy, aluminum, aluminum An alloy, copper, a copper alloy, titanium, a titanium alloy, magnesium, a magnesium alloy, etc. are mentioned.
When the separator 1 is incorporated in a fuel cell, one of the groove portions 3 of the metal substrate 2 serves as a fuel gas supply groove portion for supplying fuel gas to an adjacent unit cell, and the other is adjacent to another adjacent groove. This is an oxidant gas supply groove for supplying an oxidant gas to the unit cell. Further, 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. Further, the groove 3 may be provided only on one surface of the metal base 2. 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.

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 intermediate layers 4 and 14 constituting the separators 1 and 11 have an effect of preventing the formation of a passive film or an oxide film on the metal bases 2 and 12, and the connection resistance between the metal bases 2 and 12 and the resin layers 5 and 15. The effect | action which reduces is made. Examples of the material of the intermediate layers 4 and 14 include nickel, palladium, platinum, copper, silver, gold, ruthenium, rubidium, zinc, lead, tin, and alloys of the above metals such as tin-nickel alloys. One of these may be used alone, or two or more materials may be arbitrarily combined to form a laminated structure such as nickel / gold. The thickness of the intermediate layers 4 and 14 can be appropriately set within a range of, for example, about 0.003 to 5 μm. If the thickness of the intermediate layers 4 and 14 is less than 0.003 μm, the above-described effects are not sufficiently exhibited, and if the thickness exceeds 5 μm, it may cause a cost increase due to the use of noble metals, The cycle time becomes long, which is not preferable.

The resin layers 5 and 15 constituting the separators 1 and 11 are conductive and provide corrosion resistance to the metal bases 2 and 12. The resin layers 5 and 15 are 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.
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 layers 5 and 15 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 layers 5 and 15 is less than 0.1 μm, good corrosion resistance may not be ensured due to the occurrence of pinholes, etc. If the thickness exceeds 100 μm, the occurrence of cracks after drying and solidification and production This is not preferable because of problems such as deterioration in performance and high cost.
Examples of the conductive material contained in the resin layers 5 and 15 include carbon materials such as carbon particles, carbon nanotubes, carbon nanofibers, and carbon nanohorns, and corrosion-resistant metals. If it is obtained, it 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 layers 5 and 15. The content of the conductive material in the resin layers 5 and 15 can be set as appropriate according to the conductivity required for the resin layers 5 and 15, for example, in the range of 30 to 90% by weight. Can do.

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 above-described embodiments of the separator of the present invention are examples, and the present invention is not limited to these embodiments.

[Manufacturing method of separator]
Next, the manufacturing method of the separator for fuel cells of this invention is demonstrated.
FIG. 3 is a process diagram for explaining the manufacturing method of the present invention using the separator 1 shown in FIG. 1 as an example. In FIG. 3, resists 7 and 7 are formed in a desired pattern by photolithography on both sides of the metal plate 2 '(FIG. 3A), and the metal plate 2' is etched from both sides using the resists 7 and 7 as a mask. Thus, the groove portions 3 and 3 are formed (FIG. 3B). Thereafter, the resists 7 and 7 are removed to obtain the metal substrate 2 (FIG. 3C).
Next, the intermediate layer 4 is formed on both surfaces of the metal substrate 2 (FIG. 3D). When the metal substrate 2 has a passive film or an oxide film on the surface, the intermediate layer 4 is formed after removing these thin films. The intermediate layer 4 can be formed by a vacuum film formation method such as sputtering, vacuum deposition, or ion plating, an electrolytic plating method, an electroless plating method, or the like. The intermediate layer 4 formed in this way effectively prevents the passive film or oxide film from being regenerated on the metal substrate 2, and therefore uses a metal plate 2 ′ that is liable to generate a passive film or oxide film. In addition, the separator 1 of the present invention is easy to manufacture.

Next, a film is formed on the intermediate layer 4 by electrodeposition using an electrodeposition solution in which a conductive material is dispersed in various anionic or cationic synthetic polymer resins having electrodeposition properties, and then cured. Thus, the resin layer 5 is formed (FIG. 3E). The resin layer 5 formed in this way has good conductivity and high corrosion resistance. Thereby, the separator 1 of this invention is obtained.
FIG. 4 is a process diagram for explaining the separator manufacturing method of the present invention, taking the separator 11 shown in FIG. 2 as an example. In FIG. 4, resists 17 and 17 are formed in a desired pattern on both surfaces of the metal plate 12 'by photolithography (FIG. 4A). The resists 17 and 17 have a plurality of openings, and the openings are positioned so as to face each other through the metal plate 12 '. Next, using the resists 17 and 17 as a mask, the metal plate 12 'is etched from both sides to form a plurality of through holes 13 (FIG. 4B). Thereafter, the resists 17 and 17 are peeled off to obtain the metal substrate 12 (FIG. 4C).
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 intermediate layer 14 is formed on the metal substrate 12 including the inner wall surface of the through hole 13 (FIG. 4D). When the metal substrate 2 has a passive film or an oxide film on the surface, the intermediate layer 14 is formed after removing these thin films. The formation of the intermediate layer 14 can be performed in the same manner as the formation of the intermediate layer 4 described above.
Next, a film is formed on the intermediate layer 14 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. Thus, the resin layer 15 is formed (FIG. 4E). Thereby, the separator 11 is obtained.
The embodiments of the separator manufacturing method described above are examples, and the present invention is not limited to these embodiments.

[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. 5 is a partial configuration diagram for explaining the structure of the polymer electrolyte fuel cell, and FIG. 6 is a diagram for explaining the membrane electrode assembly constituting the polymer electrolyte fuel cell. FIG. 8 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.
5 to 8, the polymer electrolyte fuel cell 21 has a stack structure in which a plurality of unit cells each including a membrane-electrode assembly (MEA) 31 and a separator 41 are stacked. .
As shown in FIG. 6, 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.

  The separator 41 has a fuel gas supply groove 43a on one surface, a separator 41A having an oxidant gas supply groove 44a on the other surface, a fuel gas supply groove 43a on one surface, and the other surface. The separator 41B has a cooling water groove 44b on the surface, and the separator 41C has a cooling water groove 43b on one surface and an oxidant gas supply groove 44a on the other surface. Such separators 41A, 41B, and 41C are separators of the present invention, and an intermediate layer 4 and a resin layer 5 as shown in FIG. 1 are formed on both sides thereof. Yes.

  Two fuel gas supply holes 45a and 45b, two oxidant gas supply holes 46a and 46b, and two cooling water supplies are provided at predetermined positions of the separators 41A, 41B and 41C and the polymer electrolyte membrane 32. Holes 47a and 47b are formed as through holes. Then, the air electrode (oxygen electrode) 38 of the MEA 31 is in contact with the surface of the separator 41A where the oxidizing gas supply groove 44a is formed, and the surface of the separator 41B where the fuel gas supply groove 43a is formed, The fuel electrode (hydrogen electrode) 35 of the MEA 31 abuts, and the surface of the separator 41B on which the cooling water groove 44b is formed and the surface of the separator 41C on which the cooling water groove 43b is formed abut. The separators 41A, 41B, and 41C and the MEA 31 that is a unit cell are stacked, and the polymer electrolyte fuel cell 21 is configured by repeating this process. In the stacked state, the two fuel gas supply holes 45a and 45b form fuel gas supply passages penetrating in the stacking direction, and the two oxidant gas supply holes 46a and 46b are respectively formed. An oxidant gas supply path that penetrates the laminating method is formed, and the two cooling water supply holes 47a and 47b each form a cooling water supply path that penetrates in the laminating direction.

Another example of the polymer electrolyte fuel cell using the separator of the present invention will be described with reference to FIGS. 9 is a plan view for explaining the structure of the polymer electrolyte fuel cell, and FIG. 10 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. 9 and 10, 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. This is a polymer electrolyte fuel cell that is arranged and electrically connected in series to extract voltages corresponding to the number of unit cells (four in FIG. 9). 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.

In addition, as shown in FIG. 11, 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 FIG. 2, and have a conductive resin layer on a metal substrate having a plurality of through holes with an intermediate layer interposed therebetween.

Next, the present invention will be described in more detail by showing specific examples.
[ Reference 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, a photosensitive material (a mixture of casein and ammonium dichromate) is applied to both surfaces of this SUS304 by a dip coating method to form a 7 μm-thick coating film, which is exposed through a photomask for groove formation ( A resist was formed by irradiating with a 5 kW mercury lamp for 60 seconds) and developing (spraying with hot water at 40 ° C.).
Next, a ferric chloride aqueous solution heated to 70 ° C. was sprayed from both surfaces of the stainless steel plate 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 subjected to pretreatment (passive film removal) using a hydrochloric acid aqueous solution at 40 ° C. (added 1 part of 35% hydrochloric acid to 9 parts of water) and washed with water.
Thereafter, an intermediate layer (thickness 1 μm) made of nickel was formed on the metal substrate including the groove under the following electrolytic plating conditions.
(Electrolytic plating conditions)
-Bath used: Nickel chloride plating bath-pH: 1.3
・ Current density: 6A / dm ²
・ Liquid temperature: 23 ℃

  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 liquid was stirred at 20 ° C., and 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. Then, it dried with hot air (150 degreeC, 3 minutes) with the dryer, and also heat-hardened at 180 degreeC for 1 hour in nitrogen atmosphere. Thereby, a resin layer having a thickness of 15 μm was formed on the intermediate layer, and a separator was obtained.

The epoxy electrodeposition solution used 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. 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.

As a result of measuring the electrical resistance of front and back conduction in the manufactured separator by the following method, it was 6.8 mΩ, and it was confirmed that the electrical resistance was low.
(Measurement method of electrical resistance)
Separator gas diffusion layer (TGP-H-060 190μm thickness manufactured by Toray Industries, Inc.)
Between the two electrodes, and further sandwiched between 5 mm thick copper-plated copper electrodes (pressure: 20 kgf / cm ² ) to measure the resistance between the electrodes.

[ Reference 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 copper plating layer (thickness 1 μm) and a gold plating layer (thickness 0.05 μm) are sequentially laminated on the zinc alloy layer under the following electrolytic plating conditions, and an intermediate layer having a zinc / copper / gold three-layer structure. (Thickness 1.1 μm) was formed on the metal substrate including the groove.
(Copper electroplating conditions)
-Bath used: Copper cyanide bath-pH: 10.5
・ Current density: 2A / dm ²
・ Liquid temperature: 40 ℃
(Gold electroplating conditions)
-Bath used: alkaline high-purity gold plating bath-pH: 12
・ Current density: 0.4 A / dm ²
・ Liquid temperature: 60 ℃

Next, in the same manner as in Reference Example 1, a resin layer having a thickness of 15 μm was formed on the intermediate layer. Thereby, the separator of the present invention was obtained.
As a result of measuring the electrical resistance of conduction between the front and back sides of the separator thus produced by the same method as in Reference Example 1, it was 3.6 mΩ, and it was confirmed that the electrical resistance was low.

[ Example ]
A copper alloy (copper-tin-copper 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 20 μm and exposed through a photomask for forming a groove. (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 subjected to pretreatment (passivation film removal) using 50 ° C. sulfuric acid (adding 5 parts of water to 1 part of sulfuric acid) and washing with water.
Thereafter, a nickel plating layer (thickness: 1.1 μm) and a gold plating layer (thickness: 0.05 μm) are sequentially laminated under the following electrolytic plating conditions, and an intermediate layer (thickness of about 1.1 μm) having a two-layer structure of nickel / gold. ) Was formed on the metal substrate including the groove.
(Nickel electrolytic plating conditions)
-Bath used: Nickel chloride plating bath-pH: 1.3
・ Current density: 6A / dm ²
・ Liquid temperature: 23 ℃
(Gold electroplating conditions)
-Bath used: alkaline high-purity gold plating bath-pH: 12
・ Current density: 0.4 A / dm ²
・ Liquid temperature: 60 ℃

Next, in the same manner as in Reference Example 1, a resin layer having a thickness of 15 μm was formed on the intermediate layer. Thereby, the separator of the present invention was obtained.
About the separator produced in this way, as a result of measuring the electrical resistance of front and back conduction by the same method as in Reference Example 1, it was 3.3 mΩ, and it was confirmed that the electrical resistance was low.

[Comparative example]
A separator was produced in the same manner as in Reference Example 1 except that the intermediate layer was not formed.
As a result of measuring the electrical resistance of the front and back conduction in this separator by the same method as in Reference Example 1, it was 8.7 mΩ, which was larger than that of the separator of the example .

  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 fragmentary sectional view showing one embodiment of a separator for fuel cells of the present invention. It is a fragmentary sectional view which shows other embodiment of the separator for fuel cells of this invention. It is process drawing for demonstrating one Embodiment of the manufacturing method of the separator of this invention. It is process drawing for demonstrating other embodiment of the manufacturing method 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. 6 is a perspective view showing a state where the separator and the membrane electrode assembly of the polymer electrolyte fuel cell shown in FIG. 5 are separated from each other. FIG. 6 is a perspective view showing a state in which the separator and the membrane electrode assembly of the polymer electrolyte fuel cell shown in FIG. 5 are separated from a direction different from FIG. 7. It is a top view for demonstrating the other example of the polymer electrolyte fuel cell using the separator of this invention. It is a longitudinal cross-sectional view in the AA line of the polymer electrolyte fuel cell shown by FIG. 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 3 ... Groove part 4 ... Intermediate | middle layer 5 ... Resin layer 11 ... Separator 12 ... Metal base | substrate 13 ... Through-hole 14 ... Intermediate | middle layer 15 ... Resin layer 21,51 ... Polymer electrolyte fuel cell 31,61 ... Membrane electrode assembly (MEA)
41A, 41B, 41C, 71A, 71B ... separator

Claims (6)

A metal base and a conductive resin layer formed by electrodeposition so as to cover the metal base via an intermediate layer, the metal base is made of copper or a copper alloy, and the intermediate layer is the metal base A separator for a fuel cell having a two-layer structure in which nickel and gold are laminated from the side , and the resin layer contains a conductive material.   The separator for a fuel cell according to claim 1, wherein the metal substrate has a groove on at least one surface.   The separator for a fuel cell according to claim 1, wherein the metal substrate has a plurality of through holes. The separator for a fuel cell according to any one of claims 1 to 3 , wherein the conductive material is at least one of carbon particles, carbon nanotubes, carbon nanofibers, carbon nanohorns, and corrosion-resistant metals. An intermediate layer is formed by laminating nickel and gold in this order on a metal substrate made of copper or a copper alloy , and then an electrodeposition liquid in which a conductive material is dispersed in a resin having electrodeposition properties on the intermediate layer. A method for producing a fuel cell separator, wherein the resin layer is formed by electrodeposition. 6. The method for producing a fuel cell separator according to claim 5 , wherein the intermediate layer is formed immediately after removing the passive film or oxide film from the metal substrate.

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