KR101262603B1 - Fe-ni/cr metal separator for fuel cell and method of manufacturing the same - Google Patents

Abstract

PURPOSE: An Fe-Ni/Cr metal separation plate for a fuel cell is provided to show excellent intensity, hardness, durability and/or corrosion resistance, and to facilitate thickness adjustment and mass production. CONSTITUTION: An Fe-Ni/Cr metal separation plate for a fuel cell comprises an alloy thin-film of iron and nickel, and a chrome layer on both sides of the alloy thin-film of iron and nickel. A flow path shape of the separation plate for the fuel cell is formed on the Fe-Ni/Cr metal separation plate. The alloy thin-film of iron and nickel has a structure of nano-size crystal particle, and comprises 5-30 wt% of nickel, remainder iron and other unavoidable impurities.

Description

Iron-Nickel / Chrome Metal Separator for Fuel Cell and Manufacturing Method Thereof {Fe-Ni / Cr METAL SEPARATOR FOR FUEL CELL AND METHOD OF MANUFACTURING THE SAME}

The present invention is excellent in strength, hardness, durability and / or corrosion resistance and the alloy thin film metal separator plate of iron and nickel (chrome fuel Fe-Ni / Cr metal separation plate) and a method for manufacturing the same. More specifically, the present invention provides a fuel cell Fe-Ni / Cr metal separator having excellent strength, hardness, durability, and / or corrosion resistance, in which a complicated flow path shape of a metal separator plate for fuel cells is integrally formed using a horizontal electroforming method, and a preparation thereof. It is about a method.

Traditional methods of collecting energy using fossil fuels are slowly reaching their limits due to global warming, depletion of fuel resources, and environmental pollution. In particular, the prospect is that petroleum fuel will be exhausted in not too long time. In addition, the Energy Climate Convention, represented by the Kyoto Protocol, is compulsoryly required to reduce the emissions of carbon dioxide produced by the burning of fossil fuels. Therefore, the limitation of annual usage of fossil fuel is obvious not only in the present Contracting State but also in the world in the future.

In order to replace fossil fuels, researches on environmentally friendly cars that use electricity as fuels for electric cars, fuel cell cars, and hybrid cars have been actively conducted. Recently, the launch of pure electric vehicles is imminent in commercial use, but the method of operating by charging electricity from the outside has a short driving distance and a long charging time. Fuel cell cars, on the other hand, can generate electricity by supplying hydrogen from the outside, making it easy to recharge fuel, and the driving distance is almost the same as that of gasoline cars.

A fuel cell is a device that converts chemical energy by the reaction of hydrogen and oxygen into electrical energy. A polymer solid electrolyte fuel cell (PEMFC) is mainly used in automobiles. The PEMFC consists of a membrane electrode assembly, a gas diffusion layer (GDL), a gasket, a fastening mechanism, a reactor body, and a separator to move the coolant around the electrolyte membrane.

The separation plate structurally supports a fuel cell, passes a generated current, and plays various roles such as transport of hydrogen and oxygen gas, transport and removal of reaction products, and transport of cooling water for removal of reaction heat. Thus, there are flow paths of very complex shape in the separator plate for the transport of various gases and products and for the cooling water.

In the past, graphite-based separators have been mainly used to satisfy the electrical conductivity, thermal conductivity, gas tightness, and chemical stability required in the separator. However, the graphite-based separator plate is inferior in strength and hermeticity to the metal-based material and is very difficult to form, so the process cost is very high and the productivity is inferior.

Therefore, research on metal separators has been actively conducted in recent years. In particular, the metal separator can be reduced in weight by reducing the thickness of the separator and is characterized by reducing costs. However, when the thickness of the fuel cell separator is thin, it is very difficult to form the material during stamping and there is a problem that it is not easy to obtain the required mechanical strength.

One embodiment of the present invention is to provide a fuel cell Fe-Ni / Cr metal separator excellent in strength, hardness, corrosion resistance and / or durability and a method of manufacturing the same.

Another embodiment of the present invention is to provide a Fe-Ni / Cr metal separator plate for fuel cells and a method for manufacturing the same, in which a complicated flow path shape of the metal separator plate is integrally formed.

Another embodiment of the present invention is to provide a thin-film Fe-Ni / Cr metal separator for a fuel cell and a method of manufacturing the same.

Furthermore, another embodiment of the present invention is to provide a Fe-Ni / Cr metal separator for a fuel cell formed by horizontal electroforming and a method of manufacturing the same.

According to the first aspect of the present invention, a Fe-Ni / Cr metal separation for fuel cell comprising an alloy thin film of iron and nickel and a chromium layer formed on both sides of the thin film of iron and nickel alloy and the flow path shape of the separator plate for fuel cell is formed. Editions are provided.

According to the second aspect of the present invention, in the first aspect, an alloy thin film of iron and nickel has a thickness of 30 μm to 70 μm to provide a Fe-Ni / Cr metal separator plate for fuel cells.

According to the third aspect of the present invention, in the first aspect, the chromium layer is provided with a Fe-Ni / Cr metal separator plate for fuel cells having a thickness of 0.1 μm to 20 μm.

According to the fourth aspect of the present invention, in the first aspect, an iron-nickel alloy thin film is provided with a Fe-Ni / Cr metal separator for fuel cells having a nano-sized grain structure.

According to the fifth aspect of the present invention, in the first aspect, the alloy thin film of iron and nickel is a Fe-Ni / Cr metal separator for fuel cells containing 5-30% by weight of nickel, balance iron and other unavoidable impurities. Is provided.

According to the sixth aspect of the present invention,

Supplying an electrolyte solution including an iron precursor and a nickel precursor to a surface of a conductive mother plate in which a flow path shape of a separator plate for a fuel cell horizontally supplied in a predetermined direction is formed;

On the mother plate, which serves as an anode and a cathode, which are spaced apart from the surface of the mother plate where the flow path shape of the fuel cell separation plate is formed so that iron and nickel are electrodeposited on the surface of the conductive mother plate where the flow path shape of the fuel cell separation plate is formed. Applying a current;

Separating the electrodeposited layer of iron and nickel formed by electrodepositing the iron and nickel; And

Provided is a method for manufacturing a Fe-Ni / Cr metal separator plate for a fuel cell, including forming a chromium layer on both sides of an alloy thin film of iron and nickel obtained by separation of an alloy electrodeposition layer of iron and nickel.

According to the seventh aspect of the present invention, in the sixth aspect of the present invention, the fuel cell separator is provided with a fuel cell Fe-Ni / Cr metal separation plate manufacturing method is formed on one side or both sides of the conductive mother plate. do.

According to an eighth aspect of the present invention, in the sixth aspect of the present invention, the iron precursor is at least one selected from the group consisting of iron sulfate, iron chloride, iron nitrate, and iron sulfamate, and the nickel precursor is nickel sulfate, chloride A method for producing a Fe-Ni / Cr metal separator for fuel cells, which is at least one selected from the group consisting of nickel, nickel nitrate and nickel sulfamate, is provided.

In the Fe-Ni / Cr metal separator plate for fuel cells according to one embodiment of the present invention, a flow path shape of a complex fuel cell separator plate is integrally formed. The Fe-Ni / Cr metal separator for fuel cells is a thin film that is light and has excellent strength, hardness, corrosion resistance and / or durability. The Fe-Ni / Cr metal separator plate for fuel cells is manufactured by horizontal electroforming using a base plate having a complicated flow path shape of a fuel cell metal separator plate, whereby a flow path shape formed on the mother plate is transferred to an alloy thin film of Fe and Ni, thereby forming a complex. The flow path shape is integrally formed continuously. In addition, an alloy thin film of Fe and Ni is formed to have a uniform thickness by a horizontal electroforming method, the thickness can be easily adjusted, and mass production is possible. Furthermore, excellent corrosion resistance is shown.

1 is a view schematically showing an example of the configuration of a horizontal electric casting apparatus used for manufacturing a Fe-Ni / Cr metal separator for a fuel cell according to an embodiment of the present invention.
2 is a photograph of a metal separator plate for a fuel cell in which a general flow path shape is formed.

The inventors of the present invention have completed the present invention in view of the fact that the flow path shape of the fuel cell separation plate formed on the mother plate can be transferred to the Fe-Ni / Cr metal separation plate for fuel cell by horizontal electric casting.

Fe-Ni / Cr metal separator plate for fuel cells according to an embodiment of the present invention is a chromium layer on both sides of the iron and nickel alloy (hereinafter also referred to as' Fe-Ni alloy) thin film and the Fe-Ni alloy thin film It has a flow path shape of the separator for fuel cell. The Fe—Ni alloy thin film has a thickness of 30 μm to 70 μm and the chromium layers formed on both surfaces of the Fe—Ni alloy thin film have a thickness of 0.1 μm to 20 μm, respectively. In terms of handling and cost competitiveness in the fuel cell manufacturing process, the Fe—Ni alloy thin film preferably has a thickness of 30 μm to 70 μm. In addition, the Fe-Ni alloy thin film contains 5-30% by weight of nickel, balance iron and other unavoidable impurities. The thickness of the chromium layer is preferably 0.1 µm to 20 µm in view of sufficient Fe-Ni alloy thin film coating property of chromium and peeling resistance and crack resistance of the chromium layer. As such, the Fe-Ni / Cr metal separator for fuel cells is an ultra-thin film, but the Fe-Ni alloy electrodeposition layer has a nanocrystalline structure, and thus has very good mechanical strength. The size of the nanocrystals may be in the range of 1 nm to 10 nm, for example.

The Fe-Ni / Cr metal separator plate for fuel cells has excellent corrosion resistance not only by the chromium layer but also by the Fe-Ni alloy sheet. In addition, the Fe-Ni / Cr metal separator plate for fuel cells is not only excellent in strength and / or hardness, but also flexible, so that cracks or fractures due to physical impact do not easily occur, thereby ensuring excellent durability.

According to another embodiment of the present invention, a method for manufacturing a Fe-Ni / Cr metal separator plate for a fuel cell by a horizontal electroforming method is provided.

In the case of manufacturing a metal separator plate for fuel cell by the conventional rolling method, the heat treatment and rolling process must be performed several times in order to reduce the thickness of the metal separator plate, which is a complicated manufacturing process, which requires a lot of energy and time. It is difficult to maintain a constant shape. In addition, problems such as thickness variation, surface roughness are not constant, and edge cracks are generated, resulting in high manufacturing costs and difficulty in producing a wide metal electrodeposition layer.

On the other hand, when the metal electrodeposition layer is manufactured by the electroforming method using the drum cell, it is important to manage the surface of the drum in order to manufacture a thin film having a uniform thickness and surface shape. Operation is difficult. In addition, since the area of the drum surface immersed in the electrolyte determines the electrodeposition speed, the production speed is limited according to the size of the drum used for the pole, and the cost of providing a large drum is high, and thus, the limitation of replacing the drum is disadvantageous. Has Furthermore, in order to increase the production rate, the flow rate of the electrolyte solution between the anode and the cathode must be increased, but the flow rate of the electrolyte solution gradually decreases because the shape between the anode and the cathode is curved.

However, in one embodiment of the present invention, a thin film of fuel cell Fe-Ni / Cr metal separator plate having a uniform flow path shape of a complex fuel cell cell separator plate is continuously formed by using a horizontal electroforming method capable of using a high speed flow field. It can be manufactured with excellent productivity.

Fe-Ni / Cr metal separator manufacturing method for a fuel cell by horizontal electroforming according to an embodiment of the present invention is a step of supplying an electrolyte containing an iron precursor and a nickel precursor on the surface of the conductive mother plate horizontally supplied in a predetermined direction Applying a current to electrodeposit the iron and nickel on the surface of the conductive mother plate, separating the Fe-Ni alloy electrodeposition layer formed by electrodeposition of iron and nickel, and Fe-Ni obtained by separating the Fe-Ni alloy electrodeposition layer. Forming a chromium layer on both sides of the alloy thin film.

In forming the Fe-Ni / Cr metal separator plate for fuel cells by horizontal electroforming, any base plate having flexibility and conductivity may be used without particular limitation. It is preferable that such a mother plate has an oxide film, specifically, a metal oxide film formed on one surface or both surfaces. Although not limited to this as the metal oxide film, titanium oxide, chromium oxide, lithium oxide, iridium oxide, platinum oxide, etc. can be formed. Specifically, for example, a metal substrate such as stainless steel or titanium in which the metal oxide film is formed may be used. Also for example, plastic substrates having conductivity and flexibility can be used. Specifically, the conductivity and flexibility for plastic substrates can be imparted by generally known methods of forming metal oxides and / or metal layers. For example, a plastic substrate on which the metal oxide film and / or platinum layer is formed may be used.

In the case where the Fe—Ni alloy electrodeposition layer formed by electrodeposition on the mother plate is firmly bonded, the Fe—Ni alloy electrodeposition layer is difficult to be separated from the mother plate, so that an oxide film is preferably formed on the mother plate surface. Since the adhesion of the Fe-Ni alloy electrodeposition layer to the mother plate surface is weakened by the oxide film on the mother plate surface, the Fe-Ni alloy electrodeposition layer can be easily peeled from the mother plate.

The flow path shape of the separator for fuel cell is formed on the surface of the mother plate. The flow path shape of the surface of the mother plate is not particularly limited, and may be any flow path shape generally formed in the separator for fuel cell known in the art. Flow path forming method for the base plate The flow path can be formed in the base plate by any method known in the art, for example, it can be formed by pressing or stamping. The flow path shape may be formed on one side or both sides of the mother plate. In terms of productivity, it is preferable to obtain a Fe—Ni alloy thin film by forming a flow path shape on both sides of the mother plate and electrodepositing iron and nickel on both surfaces where the flow path shape is formed.

The base plate supplied horizontally in the predetermined direction may include a step of optionally and additionally cleaning the surface of the base plate as needed before the electrodeposition process. The washing of the surface of the mother plate is not particularly limited and can be performed using an acidic solution or water. The acidic solution can be any acidic solution generally known for use in substrate cleaning. Thereafter, the mother board can be dried by blowing high pressure air, hot gas, or heating the mother board.

In addition, the step of polishing the base plate to adjust the surface roughness or even surface of the base plate prior to the washing of the base plate may further include if necessary. Polishing can be performed by any method generally known in the art, and is not specifically limited. However, for example, mechanical polishing such as polishing, chemical polishing such as etching, and chemical mechanical polishing such as CMP (Chemical Mechanical Polishing) method mainly used in semiconductor processes. The chemical polishing, mechanical polishing and chemical mechanical polishing means may be used alone or in combination thereof.

Such base plates are continuously supplied into the horizontal electroforming cell and are supplied in a constant direction. Herein, the 'electro-casting cell' is supplied with an electrolytic solution on the mother plate, and the metal ions, specifically, iron ions and nickel ions are electrodeposited on the surface of the mother plate where the flow path shape is formed by the electrolytic precipitation reaction to form an Fe-Ni alloy electrodeposition layer. It can be defined as a unit cell in which the reaction to form takes place. In addition, the term “constant direction” means that the advancing direction of the mother board does not change until at least the horizontal cell exits the horizontal cell after the mother plate is supplied into the electroforming cell and proceeds in one direction. In this specification, the advancing direction of the mother plate may be referred to as 'horizontal direction' or simply 'horizontal' in some cases, and furthermore, the mother plate advances the electroforming cell in the horizontal direction so that the metal ions (iron ions and nickel) in the electrolyte The electroforming cell is also referred to as a 'horizontal cell' to indicate that ions) are electrolytically deposited on the mother plate.

For the continuous supply of the mother board, the mother board is not limited thereto, but the mother board wound up in the form of a coil can be supplied into the horizontal cell. When all of the mother boards are supplied, the mother board wound up in the form of another coil is supplied to the mother board previously supplied. Subsequently, it can be supplied continuously. At this time, if necessary, the rear end of the preceding base plate and the leading end of the following base plate can be joined by a predetermined bonding method such as welding and continuously supplied. Furthermore, in order to easily join, each terminal joined can also be processed to a suitable shape.

The base plate may be supplied horizontally into the horizontal cell by a pair of conductor rolls which contact the width edge of the base plate to transfer the base plate into the horizontal cell. In this case, the electrolytic solution may be supplied to one side of the mother plate supplied into the horizontal cell to perform electroforming on one side, and the electrolytic solution may be supplied to both sides to electrolytically deposit iron and nickel on both sides to deposit the Fe-Ni alloy electrodeposition layer. Can increase the production speed. The shape of the fuel cell separator flow path may or may not be formed on the surface of the mother plate to which the electrolyte is supplied. However, in order to obtain the Fe-Ni alloy thin film in which the flow path shape of the present invention is integrally formed, the fuel cell separator flow path shape must be formed on the surface of the mother plate.

When the mother plate is supplied into the horizontal cell as described above, the electrolyte is supplied to one or both sides of the mother plate through the electrolyte supply nozzle, and the electrolyte is moved through the horizontal flow path formed by the mother plate and the anode electrode, thereby applying the current of the cathode electrode. Electrolytic precipitation by the action of the mother plate and the anode electrode, which plays a role, precipitates iron and nickel ions on the surface of the mother plate to form an Fe-Ni alloy electrodeposition layer.

In the case of the conventional drum type electroforming cell, the mother plate shape provided as the cathode has a curvature in the shape of a drum, so that the flow path of the electrolyte also forms a curvature, and as a result, the flow rate of the electrolyte is gradually lowered, thereby lowering the electrodeposition rate, and obtaining the electrodeposited metal. There is a problem that the thickness of the layer becomes nonuniform. Furthermore, in the case of forming an oxide film on the drum surface, there is a problem that the management of the electrolyte solution is not easy because impurities are introduced into the electrolyte solution during this process.

However, in the case of the horizontal cell, since the flow path is formed horizontally, the electrolyte can be supplied at high speed without the flow rate of the electrolyte being reduced, thereby increasing the electrodeposition rate of the iron ions and the nickel ions. The supply rate of electrolyte (Re, Reynolds number) can be supplied up to 5,000, and the relative speed can be appropriately increased or decreased depending on the progress of the mother plate. In addition, depending on the state of the electrodeposition reaction, the electrolyte may be supplied at a flow rate of laminar flow (the flow of fluid supplied in a straight line without shaking the water, having straightness), and a high speed turbulence (water stem) after a stable electrodeposition reaction is formed. Can be supplied at a flow rate). If the flow rate of electrolyte is increased during initial electrodeposition, electrodeposition layer may be separated and electrodeposition may fail. If electrodeposition layer grows to several micro level, adhesion is improved by stress generated in electrodeposited layer and high speed flow field can be used. It is. On the other hand, when using a high speed flow field, the fluid supply speed region is preferably supplied at a flow rate below the surface tension between the electrodeposition layer and the mother plate, and the electrolyte is supplied at a flow rate beyond the surface tension between the electrodeposition layer and the mother plate. When supplied, the shear stress between the flow field and the electrodeposited layer due to the supply of the electrolyte exceeds the surface tension between the electrodeposited layer and the mother plate, thereby causing peeling of the electrodeposited layer.

The electrolyte is supplied to the surface of the mother plate through the nozzle from the electrolytic cell containing the electrolyte, such electrolyte may be supplied in the same direction and in the opposite direction with respect to the traveling direction of the mother plate. By doing in this way, the electrodeposition rate of an iron component and a nickel component with respect to the surface of a mother board can be raised further.

On the other hand, the electrolyte used for electrodeposition can be recovered by electrolyte storage tank again as needed. At this time, since the recovered electrolyte solution is consumed by iron ions and nickel ions by electrodeposition, the iron and nickel ion concentrations in the electrolyte reservoir will be lower than the concentrations required for electrodeposition. It can be adjusted by ion and nickel ion concentration.

The electrolyte solution includes an iron precursor and a nickel precursor to form an Fe—Ni alloy electrodeposition layer. The electrolyte is generally an aqueous solution containing a precursor of a metal to be plated, and optionally a conductive aid, a complexing agent, a stress relieving agent, and the like, so long as the electrolyte contains an iron precursor and a nickel precursor, the composition of the electrolyte is particularly The present invention is not limited thereto, and may be any electrolyte solution commonly used for electroforming. The iron precursor is not limited thereto, but may be, for example, at least one selected from the group consisting of iron sulfate, iron chloride, iron nitrate, and iron sulfamate. The nickel precursor may be at least one selected from the group consisting of, for example, but not limited to, nickel sulfate, nickel chloride, nickel nitrate and nickel sulfamate. The content of the iron precursor and the nickel precursor in the electrolyte is not particularly limited, and may be suitably adjusted according to the moving speed of the mother plate, the electrolyte supply speed, and the composition ratio of Fe and Ni in the Fe-Ni alloy electrodeposition layer (thin film). .

In one embodiment of the present invention, the ratio of Fe and Ni in the Fe-Ni alloy electrodeposition layer (thin film) is not particularly limited, but if the content of Ni is too small, the electrodeposition quality of the Fe-Ni electrodeposition layer is lowered so that the Ni content is reduced. It is preferable that it is 5-30 weight%. The Fe—Ni alloy electrodeposition layer (thin film) comprises 5-30% by weight of Ni, residual iron and other unavoidable impurities, preferably 5-30% by weight of Ni, and 70-95% by weight of iron. The other unavoidable impurities may be inevitably incorporated from raw materials or the surrounding environment in a conventional manufacturing process, and thus cannot be excluded. Since these impurities are known to those skilled in the art, not all of them are specifically mentioned herein.

 For example, in order to form a Fe-Ni alloy electrodeposition layer (thin film) having a Ni content of 5-30% by weight, the electrolytic solution is not limited thereto, but the electrolyte is 30 g to 70 g of iron precursor, 60 g to 100 g of nickel precursor, and If desired, other additives such as conventional conduction aids, complexing agents and stress relaxation agents may be included in conventional amounts.

The electrodeposition process through the horizontal cell as described above may be performed a plurality of times in succession. As described above, when the electrodeposition process through the horizontal cell is performed a plurality of times, the thickness of the Fe-Ni alloy electrodeposition layer obtained by electrodeposition in each horizontal cell can be increased, so that the thickness of the Fe-Ni alloy electrodeposition layer is required. According to the present invention, the Fe-Ni alloy electrodeposition layer having a desired thickness can be obtained even if the mother plate is supplied at a higher speed, thereby improving productivity. When a plurality of electrodeposition processes are performed, the process conditions and the composition of the electrolyte solution may be the same or different in the plurality of electrodeposition processes. The number of repetitions of the electrodeposition process is not limited, and may be appropriately selected depending on the desired degree of electrodeposition.

On the other hand, since the electrolyte may remain on the surface of the Fe-Ni alloy electrodeposition layer formed on the mother plate, it is preferable to optionally wash the surface of the Fe-Ni alloy electrodeposition layer as necessary. Such washing may be performed using an acidic solution or water, and in addition, a flexible brush or the like may be used to effectively remove the residual electrolyte. The acidic solution may be any one known to be usable for metal surface cleaning, and is not particularly limited. Such washing may be performed in a state in which a Fe—Ni alloy electrodeposition layer is formed on the mother plate, but the Fe—Ni alloy thin film may be washed after separating the Fe—Ni alloy electrodeposition layer from the mother plate. After washing, high pressure air or hot gas may be injected onto the Fe—Ni alloy electrodeposited layer or Fe—Ni alloy thin film surface, or the Fe—Ni alloy electrodeposited layer or Fe—Ni alloy thin film may be dried by heating.

The electrodeposited Fe—Ni alloy electrodeposition layer was separated from the mother plate to obtain a Fe—Ni alloy thin film. The difference in the shear stress between the base plate and the Fe-Ni alloy electrodeposition layer can be used to separate the Fe-Ni alloy electrodeposition layer from the base plate. Since the Fe-Ni alloy electrodeposition layer is bonded by the surface tension with respect to the oxide film on a base plate, it can isolate easily by the shear stress difference. Separation of the Fe—Ni alloy electrodeposition layer due to such a shear stress difference can be carried out by passing through a plurality of rollers. Furthermore, it can be separated by the shear force due to the difference in the moving speed of the Fe-Ni alloy electrodeposition layer and the moving speed of the mother plate. On the other hand, when electrodeposition is performed on both sides of the mother plate, the upper and lower Fe-Ni alloy electrodeposition layers may be separated at the same time, or may be separated by giving a time difference.

A chromium layer is formed on both sides of the Fe-Ni alloy thin film separated as described above. The chromium layer can be, for example, plated with chromium, and the plating can be carried out by any method generally known, and the plating method is not limited. For example, the Fe-Ni alloy thin film can be continuously passed through a chromium plating bath. The chromium in the chromium plating bath may be trivalent and / or hexavalent chromium. Plating apparatus Also, any plating apparatus known in the art can be used, but is not particularly limited, it is preferable to use a plating apparatus of the horizontal cell type. The plating layer forming electrolyte (hereinafter, also referred to as a 'plating solution') is not particularly limited in composition of the electrolyte as long as it includes a chromium precursor, and may be any electrolyte solution commonly used for metal plating. It may be an aqueous solution comprising a precursor of the metal to be desired and other additives such as optional conduction aids, complexing agents and stress relieving agents. The chromium precursor is not limited thereto, but, for example, chromium oxide, chromium sulfate, chromium nitrate, and potassium chromium sulfate may be used as one kind or two or more kinds thereof. For example, the plating liquid may include 140-250 g of chromium precursor per liter of water and other additives such as conductive aids, complexing agents and stress relieving agents commonly used as necessary.

On the other hand, since a plating liquid etc. may remain in the formed chromium layer, it is preferable to wash arbitrarily as needed. It can be washed with acidic solution or water. The acidic solution may be any one known to be usable for metal surface cleaning, and is not particularly limited. After washing, high pressure air or hot gas may be injected or optionally dried by heating or the like.

Thereafter, the Fe-Ni / Cr thin film may be wound. It can cut suitably according to the winding amount. The prepared Fe—Ni / Cr thin film may be used as a metal separator plate for fuel cells. On the other hand, the base plate from which the Fe-Ni alloy electrodeposition layer is separated may be wound and reused as the base plate. However, since the separated mother plate may have electrolyte or other impurities in the electrodeposition process, it is preferable to keep the surface of the mother plate clean by drying after washing. Furthermore, when the mother plate is bonded for continuous supply of the mother plate, the mother plate may be cut to an appropriate length according to the amount of winding of the mother plate, and in this case, it is preferable to cut based on the bonding portion.

Process conditions, electrolyte composition, and chromium plating solution composition are not particularly limited in the Fe-Ni / Cr metal separator manufacturing process for fuel cells, and may be performed by methods, conditions, and compositions generally performed in electroforming and plating processes. have.

Hereinafter, a method of manufacturing a Fe-Ni / Cr metal separator for a fuel cell by a horizontal electroforming method according to an embodiment of the present invention will be described with reference to the horizontal pole apparatus of FIG. 1. FIG. 1 is not limited to FIG. 1 as an example of a horizontal pole apparatus, which is used to manufacture a Fe-Ni / Cr metal separator plate for a fuel cell by a horizontal electroforming method according to one embodiment of the present invention.

The horizontal pole device 100 includes a mother plate supply device 10, a horizontal cell 30, an electrolyte supply device and a Fe-Ni thin film separator (51).

The mother plate feeding device 10 may include a winding machine for supplying the mother plate 11. In order to continuously supply the base plate 11, a plurality of the winding machines may be installed, and when the base plate 11 is exhausted in one winding machine, a new base plate 11 may be supplied from another winding machine. For the continuous supply of such base plates 11, optionally and additionally, a joining device 12, such as welding, for joining the ends of the pre-supplied base plate 11 and the tip of the base plate 11 to be provided next is optionally required. It may include.

Further, at least one surface of the mother plate, preferably on both sides, has a flow path shape of the metal plate for fuel cell, and the flow path shape of the surface of the mother plate is transferred to the Fe—Ni alloy electrodeposition layer deposited on the surface of the mother plate by electroforming. .

On the other hand, the electrodeposition layer electrodeposited on the base plate 11 transfers the surface roughness of the base plate 11, so that the Fe-Ni alloy thin film obtained by the surface roughness of the base plate 11 is almost the same. Therefore, the grinding means 13 for adjusting the surface roughness of the base plate 11 may be further included as necessary. Such polishing means 13 is not particularly limited, and may include mechanical polishing such as polishing, chemical polishing such as etching, and chemical mechanical polishing such as CMP (Chemical Mechanical Polishing) method mainly used in semiconductor processes. The chemical polishing, mechanical polishing and chemical mechanical polishing means may be used alone or in combination thereof. By this polishing means, the surface of the base plate 11 can be arbitrarily evenly and conveniently adjusted to the desired surface roughness as necessary.

Furthermore, since impurities may be present on the surface of the mother plate 11, additional washing may be necessary as necessary to remove them, and thus, the pre-cleaning device 14 may be additionally included as necessary. The cleaning of the surface of the base plate 11 may use an acid solution such as diluted hydrochloric acid or sulfuric acid or water. After washing, a drying apparatus (not shown) for drying the base plate 11 may be further included as necessary. Drying can be performed by adding air at high pressure, or adding a hot gas, or can also be performed by heating the base plate 11.

The horizontal pole device 100 includes a horizontal cell 30 separated from the mother plate feeding device 10. In the case of a conventional electroplating apparatus using a drum, there is a problem that foreign matters generated during polishing to control the surface roughness on the drum surface are contaminated with the electrolyte and contaminate the electrolyte. Since it is separated, contamination of the electrolyte solution can be prevented.

The horizontal cell 30 is spaced apart at regular intervals from the conductor rolls 31 and 31 ′, which serve to transfer the base plate 11 and connect the cathode power, and the base plate 11. Currents having negative (+) and positive (+) charges are respectively applied to the anode electrode 32, the conductive rolls 31, 31 ′, and the anode electrode 32 disposed on one or both surfaces of the mother plate 11. And a current supply device 33 for supplying and an electrolyte supply device for receiving the electrolyte solution.

The conductor rolls 31 and 31 'function as a transfer means for transporting the base plate 11 into the horizontal cell 30 and discharging it from the horizontal cell 30, and supplying current with the base plate 11. The cathode power source of the apparatus 33 is connected to perform an electrolytic precipitation reaction in which iron and nickel ions are deposited on the base plate 11 by an electrolytic reaction between the anode electrode 32 and the base plate 11. These conductor rolls 31 and 31 'contact the two edges in the width direction of the base plate 11 to transfer the base plate 11 into the horizontal cell 30 and discharge it from the horizontal cell 30.

Since the mother plate 11 uses a flexible conductive mother plate, a drooping phenomenon may occur when passing through the horizontal cell 30. In this case, the gap between the mother plate 31 and the anode electrode 32 is changed. This may cause a difference in current density, and thus a Fe-Ni alloy thin film of uniform thickness may not be obtained. Accordingly, in order to prevent the base plate 11 from sagging, the rotational speeds of the inlet conductor roll 31 and the outlet conductor roll 31 'are varied, that is, the outlet conductor roll 31' is rotated. It is preferable to make the speed faster than the rotational speed of the inlet-side conductor roll 31 to prevent sagging due to the weight of the mother plate.

Meanwhile, the conductive rolls 31 and 31 ′ transmit current supplied from the current supply device 33 to the base plate 11 so that the base plate 11 can function as a cathode electrode. It is possible to cause the electrolytic precipitation reaction by the action of 32).

The anode electrode 32 may be spaced apart from the base plate 11 at regular intervals on one or both sides of the base plate 11 in order to cause an electrolytic precipitation reaction of metal on the base plate 11. Preferably, the anode electrode 32 may be spaced apart from each other on the base plate 11. The anode electrode 32 may be spaced apart from the base plate 11 with or without a flow path shape, but in order to obtain a metal separation plate having a flow path shape, the anode electrode 32 should be installed on the side of the base plate 11 with a flow path shape. . Since the anode electrode 32 and the mother plate 11 are spaced apart, a flow path through which an electrolyte is supplied and distributed therebetween is provided, and as described above, by the action of the anode electrode 32 and the mother plate 11 which is a cathode electrode. An electrolytic reaction may occur in which iron ions and nickel ions in the electrolyte are electrolytically deposited on the mother plate. On the other hand, by supplying the electrolyte at high speed, the electrodeposition speed of the iron and nickel ions to the surface of the base plate 11 can be increased. In the case of a conventional pole cell using a pole, because the flow path to form a curvature, the flow rate of the electrolyte is gradually slowed, there was a problem that the electrodeposition speed is lowered. However, in the method according to the present invention, since the flow path of the electrolyte is formed in a plane, the decrease in the speed of the flow field with respect to the supply of the electrolyte is prevented.

The current supply device 33 supplies (-) current and (+) current to the conductive rolls 31, 31 'and the anode electrode 32, respectively, as long as it can be applied without particular limitation. As applicable to the present invention, a detailed description thereof will be omitted.

The electrolyte supply apparatus includes an electrolyte storage tank 34 for storing and containing an electrolyte solution and an electrolyte supply nozzle 38 for supplying an electrolyte solution to the surface of the base plate 11. The electrolyte is transferred from the electrolyte reservoir 34 to the electrolyte supply nozzle 38 through an electrolyte supply pipe. The electrolyte supply nozzle 38 may be installed to be supplied only to one surface of the mother plate 11, or may be installed on both sides of the electrolyte supply to both surfaces of the mother plate 11. However, in order to obtain the Fe-Ni thin film having the flow path shape of the separator for fuel cell, an electrolyte solution must be supplied to the surface of the base plate on which the flow path shape is formed.

The electrolytic solution is, for example, an iron precursor selected from the group consisting of iron sulfate, iron chloride, iron nitrate and iron sulfamate 30 to 70 g / l, a nickel precursor selected from the group consisting of nickel sulfate, nickel chloride, nickel nitrate and nickel sulfamate And from 60 to 100 g / l, and optionally any other additives such as conduction aids, complexing agents, and stress relieving agents, may be further included as needed in amounts generally used in the art.

Meanwhile, the electrolyte storage tank 34 includes an electrolyte heater 35 for heating the electrolyte, an electrolyte filter 36 for removing impurities such as sludge included in the electrolyte, and an electrolyte pump 37 for supplying the electrolyte to the horizontal cell. Etc. may be further included as needed.

On the other hand, compared to the center of the base plate 11, the current density may be relatively lower at both edges in the width direction in some cases, the amount of electrodeposited iron and nickel is less at the edge of the base plate 11, the alloy of iron and nickel The thickness of the thin film becomes relatively thin and the overall uniform thickness of the Fe-Ni alloy thin film may not be obtained. In this case, when the obtained Fe—Ni electrodeposition layer is separated from the mother plate 11, the edge of the Fe—Ni alloy thin film may be torn and a defect may occur. In order to make the Fe—Ni alloy thin film separated from the base plate 11 to have a uniform thickness, a post-treatment process of cutting a thin edge is required. Therefore, it is necessary to prevent the precipitation of iron and nickel in the edge portion of the mother plate to prevent the thickness variation, for this purpose it may be provided with an edge mask (not shown) so that the electrolyte is not supplied to the edge of the mother plate. . By providing such an edge mask, formation of a thin Fe-Ni electrodeposition layer at the edge of the base plate 11 is prevented.

The electrolyte supply nozzle 38 supplies the electrolyte at a high speed through the horizontal passage formed by the mother plate 11 and the anode electrode 32. In this case, the electrolyte may be installed such that the electrolyte is supplied in the same direction and in the opposite direction to the traveling direction of the base plate 11 with respect to the electrolyte supply nozzle 38. By doing in this way, the effect of electrodeposition substantially can be acquired. That is, the electrolyte supplied in the opposite direction has a short time for the electrolyte contacting the mother plate 11 due to the difference in relative speed with the mother plate 11, thereby obtaining the effect of primary electrodeposition in which a relatively small amount is electrodeposited. The electrolyte supplied in the direction can contact the base plate 11 for a longer time to obtain the effect of secondary electrodeposition in which a relatively large amount of electrodeposits are electrodeposited compared to the primary electrodeposition.

The horizontal cells 30 as described above may be provided in plural in series in the traveling direction of the mother plate 11. Even if a plurality of horizontal cells 30 are installed, the electrodeposition layer is not separated from the mother plate 11 during movement by being disposed in series in the traveling direction of the mother plate 11. By installing a plurality of horizontal cells, an electrodeposition layer having a desired thickness can be formed on the base plate 11 even though the base plate is advanced at a higher speed while reducing the electrodeposition amount through one cell, thereby improving the productivity of the iron thin film. have. Electrodeposition conditions and electrolyte solutions in the plurality of horizontal cells 30 may be the same or different.

For example, the first horizontal cell and the second horizontal cell are installed, the electrode is electrodeposited on the base plate in the first horizontal cell, and further Fe- is deposited on the electrodeposition layer electrodeposited on the base plate in the second horizontal cell. The Ni alloy electrodeposition layer can be electrodeposited. By providing a plurality of horizontal cells as described above, an electrodeposition layer having a desired thickness can be formed on the mother board even though the mother board proceeds at a higher speed while reducing the electrodeposition amount through one cell, thereby improving the productivity of the Fe-Ni alloy electrodeposition layer. Can be improved. Electrodeposition conditions and electrolyte composition in the first horizontal cell and the second horizontal cell may be the same or different.

The base plate 11 having the electrodeposited layer formed thereon is discharged through the outlet conductor roll 31 ′, and after discharge, the Fe-Ni electrodeposited layer is removed from the base plate 11 by the Fe-Ni thin film separator 51. Isolate to obtain a Fe—Ni thin film. Since the Fe-Ni thin film is coupled by surface tension on the base plate 11 having an oxide film formed on the surface thereof, the Fe-Ni thin film may be separated by a difference in shear force between the Fe-Ni thin film and the base plate 11. Therefore, the Fe-Ni thin film separator 51 is preferably capable of imparting a shear stress for separating the Fe-Ni thin film from the mother plate 11, for example, can be provided with a plurality of rollers. In addition, the difference between the moving speed of the Fe-Ni thin film and the mother plate 11 may be separated by the simultaneous or time difference between the upper and lower Fe-Ni thin film.

The Fe—Ni alloy thin film may have a thickness of 30 μm to 70 μm. In addition, the Fe-Ni alloy thin film may be, for example, a nanocrystalline structure having a size ranging from 1nm to 10nm. The Fe—Ni alloy thin film may include 5 to 30 wt% nickel, balance iron and other unavoidable impurities, preferably 5 to 30 wt% nickel, and 70 to 95 wt% iron.

In the Fe-Ni thin film obtained by separating the Fe-Ni electrodeposition layer separator 51, chromium layers are formed on both sides of the Fe-Ni thin film in the chromium plating apparatus P. The chromium layer may have a thickness of 0.1 μm to 20 μm.

The chromium plating apparatus P may be any plating apparatus generally known to be used for metal plating in the art, and is not particularly limited. For example, the chromium plating apparatus P may be a horizontal cell plating apparatus. The plating bath may also be a general plating bath known to be used for chromium plating. The plating liquid used for forming the chromium layer is not limited thereto, and, for example, at least one chromium precursor selected from the group consisting of chromium oxide, chromium sulfate, chromium nitrate, and potassium chromium sulfate may be used as the chromium precursor 140-250 g / L and aqueous solutions containing conventional additives in conventional amounts, such as conducting aids, complexing agents and stress relieving agents, which are commonly used, may be used as needed.

By forming a chromium layer on both sides of the Fe-Ni thin film, a Fe-Ni / Cr metal separator for a fuel cell according to one embodiment of the present invention is obtained. The Fe—Ni thin film on which the chromium layer is formed may be optionally washed and dried as necessary to remove a plating solution that may remain on the surface of the chromium layer. Thus, it may optionally further comprise a washing device and / or a drying device (not shown) as necessary. The cleaning device is a device for removing an acid solution such as hydrochloric acid and / or sulfuric acid diluted with an electrolyte solution and foreign matter that may be present on the surface of a metal, and using a conventional device such as a high pressure spray. The drying apparatus may be an injector for injecting air at a high pressure or injecting hot gas, or may be a heating apparatus for heating and drying.

The Fe-Ni / Cr metal separator 50 for fuel cell and the mother plate 11 on which the Fe-Ni electrodeposition layer is peeled off are wound by a metal separator winding device 55 and a mother plate winding device 72, respectively. The winding devices 55 and 72 can be, for example, cylindrical winding machines. The winding devices 55 and 72 may be wound in an appropriate amount according to the winding amount, and may be wound and wound around another winding machine. Accordingly, the cutting apparatus may further include any additional fuel cell Fe-Ni / Cr metal separator cutting device 54 and mother plate cutting device 71 as necessary for the cutting. The cutting is more preferably cut at the bonding site of the mother plate.

On the other hand, the horizontal electroplating apparatus 100 is discharged from the horizontal cell 30 as necessary before or after separating the Fe-Ni thin film, if necessary, the mother plate, Fe-Ni electrodeposition layer and / or Fe- The after-treatment apparatus of Ni thin film can be further provided. Such a post-treatment device may include a post-cleaning device 52, and / or a drying device (not shown).

The cleaning device 52 is removed using an acid solution or water such as hydrochloric acid or sulfuric acid diluted with electrolyte and foreign substances that may exist on the surface of the base plate 11, the Fe—Ni electrodeposition layer, and / or the Fe—Ni thin film. As the device to be used, a normal device such as a high pressure spray can be used. The drying apparatus is an injector which injects air at high pressure or injects hot gas in order to remove the cleaning liquid present on the surface of the base plate 11, the Fe—Ni electrodeposition layer, and / or the Fe—Ni thin film after washing. It may be a heating device for drying by heating.

In the manufacturing process of the Fe-Ni / Cr metal separator for fuel cells by the horizontal electroforming process, the process conditions, the electrolyte composition, the plating solution composition, etc. are not particularly limited, and the range and composition generally performed in the electroforming and plating processes. This can be done.

As described above, the method of manufacturing a Fe-Ni / Cr alloy foil and the horizontal pole device by the pole method according to each embodiment of the present invention has been described, but such a method and the device are not limited to these embodiments. It will be understood by those skilled in the art that the present invention may be appropriately modified.

Hereinafter, the present invention will be described in detail with reference to Examples. The following examples are provided to aid the understanding of the present invention, and thus do not limit the present invention.

Example 1

STS 304 steel sheet stamped on both sides of the flow path of the general fuel cell metal separator plate of FIG. 2 as a mother plate through the mother plate supply device 10 and the conductor roll 31 of the horizontal pole device having the configuration as shown in FIG. It is supplied between the anode electrode 32 of the supply at a feed rate of 50mpm (meter per minute), the electrolyte solution through the electrolyte nozzle 38 to the electrolyte flow path formed by the anode electrode 32 and the mother plate 11 of the electro-cell Was fed in Reynolds number (Re) 1000. The electrolyte solution includes FeSO ₄ · 7H ₂ O 50g / l, NiSO ₄ · 6H ₂ O 80g / l, H ₃ BO ₃ 20g / l, NaCl 30g / l, and saccharin 3g / l, pH 1.5 ~ 3.5 And aqueous solution with a temperature of 45-60 degreeC was used. An electrolytic reaction was carried out at a current density of 5 to 8 A / dm 2 to form a Fe—Ni electrodeposition layer having a thickness of 50 μm on both sides of the mother plate. The formed Fe—Ni electrodeposition layer was separated to obtain a Fe—Ni thin film. The thin film thus obtained was sufficiently washed with water and then dried. The prepared Fe—Ni thin film contains 29 wt% nickel, iron and other unavoidable impurities, and the size of the nanocrystal was 10 nm.

CrO ₃ 250g / l and H ₂ SO ₄ 2.5g / l on both sides of the obtained Fe-Ni thin film, and the current density of 20A / dm 2 using an aqueous solution of pH 2 ~ 3, temperature 45 ℃ as a chromium plating solution Electroplated. At this time, three kinds of Fe-Ni / Cr metal separator plates for fuel cells were prepared by adjusting the thickness of the chromium layer to 1 μm, 3 μm, and 20 μm, respectively.

The contact resistance and corrosion current of the manufactured Fe-Ni / Cr metal separator plate and SUS316L substrate for fuel cell were measured by the following method, and are shown in Table 1 below.

Contact resistance was measured by the Davies method (DP Davies, J. Power Sources 86 (2000) p.237) by applying a current of 5 A at a contact pressure of 50 ~ 150 N / ㎠ at room temperature.

Corrosion test is H ₂ SO ₄ The Fe-Cr metal separator specimen prepared above was added to a mixed test solution having a concentration of 0.001 N and 5 ppm of HF, and evaluated by corrosion current data of SCE (Saturated Calomel Electrode) obtained by applying a current of 0.6 V at 80 ° C.

The fuel cell characteristics were ETEK's ELAT 0.5mg Pt / ㎠ carbon fiber paper and Fe-Ni / Cr metal separator prepared as electrode and Dupont's Nafion 112 as electrolyte membrane and the cell (cell) temperature 80 ℃, The stoichiometric ratio (volume ratio) of hydrogen / air was measured at 1.5 / 2.0, atmospheric pressure, and 1 A / cm 2, showing a sufficient operating voltage of 0.59 V on all three Fe-Ni / Cr metal separators.

Metal separator Contact resistance (mΩ㎠) Corrosion Current (mA / ㎠) Example 1
(Chromium layer thickness 1 μm) 37.6 1.56 Example 1
(Chrome layer thickness 3㎛) 36.3 1.34 Example 1
(Chromium layer thickness 20 µm) 35.1 1.17 SUS316L 39 5.2

As shown in Table 1, the Fe-Ni / Cr metal separators having a chromium layer thickness of 1 μm, 3 μm, and 20 μm prepared in Example 1 had lower contact than SUS316L substrates used as conventional fuel cell metal separators. It shows resistance and corrosion current. It can be seen from the low contact resistance and the corrosion current that the Fe-Ni / Cr metal separator is suitable for use in fuel cells and exhibits excellent corrosion resistance in view of SUS316L. In addition, as the thickness of the chromium layer increases, the corrosion current decreases, and it can be seen that the corrosion resistance is improved therefrom. As the chromium layer thickness increased, the contact resistance also decreased.

10: Bedplate Feeder 11: Bedplate
12: bonding means 13: polishing means
14: pre-washing device 30: horizontal cell
31, 31 ': Conductor roll 32: anode electrode
33: current supply device 34: electrolyte reservoir
35: electrolyte heater 36: electrolyte filter
37: electrolyte pump 38: electrolyte nozzle
50: Fe-Ni / Cr thin film 51: thin film separator (peel roll)
52: post-cleaning device 54: metal separator cutting device
55: metal separator winding device 71: plate cutting device
72: base plate winding device 100: horizontal pole
P: Plating Device

Claims (8)

Fe-Ni / Cr metal separator plate for fuel cell comprising an alloy thin film of iron and nickel and a chromium layer formed on both sides of the alloy thin film of iron and nickel, the flow path shape of the separator for fuel cell.
2. The Fe-Ni / Cr metal separator for fuel cells according to claim 1, wherein the alloy thin film of iron and nickel has a thickness of 30 µm to 70 µm.
The fuel cell of claim 1, wherein the chromium layer has a thickness of 0.1 μm to 20 μm.
The Fe-Ni / Cr metal separator for fuel cells according to claim 1, wherein the alloy thin film of iron and nickel has a nano-size grain structure.
The Fe-Ni / Cr metal separator for fuel cells according to claim 1, wherein the alloy thin film of iron and nickel contains 5-30 wt% nickel, balance iron and other unavoidable impurities.
Supplying an electrolyte solution including an iron precursor and a nickel precursor to a surface of a conductive mother plate in which a flow path shape of a separator plate for a fuel cell horizontally supplied in a predetermined direction is formed;
On the mother plate, which serves as an anode and a cathode, which are spaced apart from the surface of the mother plate where the flow path shape of the fuel cell separation plate is formed so that iron and nickel are electrodeposited on the surface of the conductive mother plate where the flow path shape of the fuel cell separation plate is formed. Applying a current;
Separating the electrodeposited layer of iron and nickel formed by electrodepositing the iron and nickel; And
A method of manufacturing a Fe-Ni / Cr metal separator for a fuel cell, comprising forming a chromium layer on both sides of an alloy thin film of iron and nickel obtained by separating the alloy electrodeposition layer of iron and nickel.
The method of claim 6, wherein the flow path shape of the separator for fuel cell is formed on one or both surfaces of the conductive mother plate.
The method of claim 6, wherein the iron precursor is at least one selected from the group consisting of iron sulfate, iron chloride, iron nitrate and iron sulfamate, and the nickel precursor is a group consisting of nickel sulfate, nickel chloride, nickel nitrate and nickel sulfamate At least one selected from, Fe-Ni / Cr metal separator for fuel cell manufacturing method.

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