KR101353808B1 - Method of manufacturing iron and nickel alloy substrate for solar cell - Google Patents

Abstract

The present invention relates to a method of manufacturing a Fe-Ni alloy substrate for a solar cell that can ensure a constant surface roughness by the horizontal electroforming method to improve the solar cell efficiency. According to the present invention, at least one selected from the group consisting of iron precursors 2g / l to 25g / l, nickel precursors 40g / l to 60g / l and sodium laureth sulfate on one or both sides of the conductive base plate horizontally supplied in a constant direction Supplying an electrolyte solution containing 0.1 g / l to 4.0 g / l surfactant; Applying an electric current to the conductive base plate serving as a cathode and an anode electrode provided spaced apart from one or both surfaces of the conductive base plate such that iron and nickel are electrodeposited on the conductive base plate; And separating an alloy electrodeposition layer of iron and nickel formed by electrodeposition of iron and nickel, thereby obtaining a Fe-Ni alloy substrate for a solar cell. The surface roughness of the substrate can be efficiently controlled by the method according to one embodiment of the present invention to continuously produce a Fe-Ni alloy substrate for solar cells that can increase the energy efficiency of the solar cell with excellent productivity. In addition, the alloy foil of Fe and Ni is formed to have a uniform thickness by the horizontal electroforming method, the thickness can be easily adjusted, and mass production is possible. In addition, the Fe-Ni alloy substrate for solar cells manufactured by the above method is light in weight and has excellent strength, hardness, durability and / or corrosion resistance. In addition, the thermal expansion coefficient is optimized by controlling the content of nickel.

Description

Manufacturing method of alloy substrate of iron and nickel used for solar cell {METHOD OF MANUFACTURING IRON AND NICKEL ALLOY SUBSTRATE FOR SOLAR CELL}

The present invention relates to a method of manufacturing an alloy substrate of iron and nickel (hereinafter also referred to as "Fe-Ni alloy substrate") used for solar cells by a horizontal electroforming method. In particular, the present invention relates to a method of manufacturing a Fe-Ni alloy substrate used for solar cells that can improve the solar cell efficiency by ensuring a constant surface roughness by the horizontal electroforming method.

Due to global warming, exhaustion of fuel resources and environmental pollution, traditional energy harvesting methods using fossil fuels are reaching their limits. 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, it is obvious that the annual consumption of fossil fuels will be limited not only in the present Contracting State but also in the future.

Representative alternative energy sources for fossil fuels include nuclear power. Nuclear power generation has been spotlighted as a viable alternative energy source that can replace fossil fuels such as petroleum since it has a large amount of energy that can be collected per unit weight of uranium or plutonium as a raw material and does not generate greenhouse gases such as carbon dioxide.

However, the explosion of the former Soviet Union Chernobyl nuclear power plant and Japan's Fukushima nuclear power plant caused by the Great East Japan Earthquake has led to a review of the safety of nuclear power, which has been regarded as an infinite clean energy source. It is requested.

Another source of energy widely used as alternative energy is hydro power generation. However, hydroelectric power is highly influenced by topographical factors and climate, so its use is limited. In addition, other alternative energy sources are also unlikely to be used as fossil fuel alternatives due to their low power generation or limited use areas.

However, solar cells can be used anywhere as long as the proper amount of sunshine is ensured, and the power generation capacity and equipment size are almost directly proportional to each other. Therefore, when used for small-capacity applications such as homes, solar cells can be installed by installing a small area on the roof of a building. There is an advantage, and not only is its use globally, but its research is also increasing.

The solar cell is based on the principle of a semiconductor. When a light having a certain level or more of energy is irradiated to a pn-bonded semiconductor, the solar cell is excited to move freely, thereby generating an electron hole pair (EHP). Create The generated electrons and holes move to the electrode located on the opposite side to generate an electromotive force.

In the first form of the solar cell, a pn junction is formed by doping an impurity (B) to a silicon substrate to form a p-type semiconductor and then doping another impurity (P) thereon to form a n-type semiconductor part of the layer. It is called the first generation solar cell as a silicon-based solar cell.

Since the silicon-based solar cell has a relatively high energy conversion efficiency and cell conversion efficiency (ratio of conversion efficiency in mass production to the best energy conversion efficiency in the laboratory), the degree of commercialization is the highest. However, in order to manufacture the silicon-based solar cell module, not only has to go through a rather complicated process step of first manufacturing an ingot from a material, wafer ingots, and then manufacturing and modularizing a cell, but also using a bulk material. There is a problem that the manufacturing cost increases because of increased material consumption.

Moreover, the silicon-based solar cell should have a single crystal or polycrystalline silicon crystal form. In order to manufacture silicon having a single crystal or polycrystal, not only a complicated manufacturing process is required but also a manufacturing cost increases.

In order to solve the disadvantage of the silicon-based solar cell, a thin-film solar cell called a second generation solar cell has been proposed. The thin film type solar cell is manufactured in the form of stacking a thin film layer sequentially on a substrate instead of a silicon wafer, instead of manufacturing the solar cell in the above-described process, and thus has a simple manufacturing process, a thin thickness, and a low manufacturing cost.

As the substrate to be applied to the thin film solar cell, an organic flexible substrate having excellent flexibility and easy winding and development in consideration of workability and workability is mainly used. However, since the organic flexible substrate is not sufficiently secured in heat resistance and is easily deformed by heating, there is a disadvantage in that the temperature of the substrate cannot be increased when forming the light absorbing layer. In addition, since the organic flexible substrate is generally a resin substrate having a low moisture permeability, durability is a problem when used outdoors for a long time, and easily degraded by external impact or abrasion.

In addition, since the thin film type solar cell has generally lower energy conversion efficiency than a silicon based solar cell, in order to solve this problem, a solar cell substrate is provided with a certain level of surface roughness so that incident light is not easily emitted. Techniques for increasing efficiency have been developed. However, these techniques require complex processes or high manufacturing costs in order to impart nano-sized surface roughness.

One embodiment of the present invention is to provide a method for manufacturing a Fe-Ni alloy substrate for a solar cell that can increase the energy efficiency of the solar cell by controlling the surface roughness of the substrate.

Another embodiment of the present invention is to provide a method for producing a Fe-Ni alloy substrate for solar cells with an optimized thermal expansion coefficient.

Another embodiment of the present invention is to provide a method for producing a Fe-Ni alloy substrate for solar cells excellent in strength, hardness, corrosion resistance and / or durability.

Furthermore, the present invention is to provide a method for producing a Fe-Ni alloy substrate for solar cells capable of continuous process and excellent productivity.

Another embodiment of the present invention is to provide a method for producing a flexible thin film Fe-Ni alloy substrate for solar cells.

According to the first aspect of the present invention,

0.1 g / at least of a surfactant selected from the group consisting of iron precursors 2g / l to 25g / l, nickel precursors 40g / l to 60g / l and sodium laureth sulfate on one or both sides of the conductive base plate horizontally fed in a constant direction supplying an electrolyte comprising 1 to 4.0 g / l;

Applying an electric current to the conductive base plate serving as a cathode and an anode electrode provided spaced apart from one or both surfaces of the conductive base plate such that iron and nickel are electrodeposited on the conductive base plate; And

Separating the alloy electrodeposition layer of iron and nickel formed by electrodepositing the iron and nickel to obtain an alloy foil of iron and nickel, there is provided a method for producing an alloy substrate of iron and nickel used for solar cells.

According to a second aspect of the present invention, in the first aspect, 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, nickel chloride, A method for producing an alloy substrate of iron and nickel for use in a solar cell, which is at least one selected from the group consisting of nickel nitrate and nickel sulfamate, is provided.

According to the third aspect of the present invention, in the first aspect, the Fe-Ni alloy substrate for solar cells has an uneven surface having a surface roughness (Rz) of 0.05 µm to 0.1 µm, and is composed of iron and nickel used for solar cells. A method for producing an alloy substrate is provided.

According to the fourth aspect of the present invention, in the first aspect, the Fe—Ni alloy substrate includes 34 wt% to 62 wt% nickel, balance iron and other unavoidable impurities, and iron and nickel used for solar cells. Provided is a method for producing an alloy substrate.

The surface roughness of the substrate can be efficiently controlled by the method according to one embodiment of the present invention to continuously produce a Fe-Ni alloy substrate for solar cells that can increase the energy efficiency of the solar cell with excellent productivity. In addition, the alloy foil of Fe and Ni is formed to have a uniform thickness by the horizontal electroforming method, the thickness can be easily adjusted, and mass production is possible. In addition, the Fe-Ni alloy substrate for solar cells manufactured by the above method is light in weight and has excellent strength, hardness, durability and / or corrosion resistance. In addition, the thermal expansion coefficient is optimized by controlling the content of nickel.

1 is a view schematically showing an example of the configuration of a horizontal electric casting apparatus used for manufacturing a Fe-Ni alloy substrate for a solar cell according to an embodiment of the present invention.

The present invention is based on controlling the surface roughness of a metal surface on which a metal electrodeposition layer grows on a cathode base plate by manufacturing a Fe-Ni alloy substrate by a horizontal electroforming method using an electrolyte solution containing a surfactant. Specifically, the efficiency of the solar cell can be improved by optimizing the surface roughness of the substrate.

In the case of manufacturing a metal separator for solar cells by the conventional rolling method, it is necessary to undergo several heat treatment and rolling processes to reduce the thickness of the metal separator. This method is complicated in manufacturing process and consequently a lot of energy and cost in the process. And there is a problem that takes time, it is difficult to maintain a constant shape. In addition, there is a problem in that thickness variation occurs, surface roughness is not constant, and edge cracks occur, manufacturing costs are high, and there is a difficulty in manufacturing a wide metal electrodeposition layer. In addition, in order to use as a solar cell substrate, it is necessary to manage the surface roughness of the substrate. In the case of manufacturing the substrate by the rolling method, inclusions are distributed in the surface layer, which makes it difficult to control the surface roughness.

On the other hand, when manufacturing a metal electrodeposition layer by the electroforming method using a drum cell, management of the drum surface is important in order to manufacture the thin film which has uniform thickness and surface shape. However, there is a disadvantage in that the operation of the drum surface must be stopped for the entire process. In addition, since the electrodeposition speed is determined according to the area of the drum surface immersed in the electrolyte, the production speed is limited depending on the size of the drum used in the pole, and there is a problem that the use of a large drum is expensive. In addition, in order to increase the production rate, the electrolyte flow rate between the anode and the cathode must be increased, but since the shape between the anode and the cathode is composed of curvature, the electrolyte flow rate gradually decreases.

However, in one embodiment of the present invention, by using a horizontal electroforming method, it is possible to continuously manufacture an alloy substrate of iron and nickel used for thin film solar cells. In addition, not only an alloy electrodeposition layer of iron and nickel can be formed on both sides of the mother plate at the same time, but also a high-speed flow field through which the electrolyte is supplied at high speed can be used, thereby improving productivity.

In the method of manufacturing a Fe-Ni alloy substrate for a solar cell by horizontal electroforming according to an embodiment of the present invention, supplying an electrolyte solution to a conductive base plate which is horizontally supplied in a predetermined direction, so that iron and nickel are electrodeposited on the surface of the conductive base plate. The step of applying a, and a step of obtaining a Fe-Ni alloy foil by separating the Fe-Ni alloy electrodeposition layer formed by electrodepositing iron and nickel.

In forming the Fe-Ni alloy substrate for solar cells by horizontal electroforming, any substrate having flexibility and conductivity may be used as the substrate without particular limitation. It is preferable that such a mother plate has an oxide film, specifically, a metal oxide film formed on one or both surfaces. As the metal oxide film, titanium oxide, chromium oxide, lithium oxide, iridium oxide, platinum oxide, or the like may be formed although not limited thereto. 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 above-described metal oxide film and / or platinum layer is formed may be used.

When the Fe—Ni alloy electrodeposition layer formed by electrodeposition on the mother plate has a firm bond with the mother plate, it is not easy to separate the Fe—Ni alloy electrodeposition layer from the mother plate, so that an oxide film is preferably formed on the mother plate surface. Even if the Fe—Ni alloy electrodeposition layer is electrodeposited on the surface of the mother plate due to the oxide film on the surface of the mother plate, since the adhesion to the surface of the mother plate is weak, the Fe—Ni alloy electrodeposition layer can be easily peeled from the mother plate.

If necessary, the surface roughness of the mother plate may be controlled. As such, the surface of the mother plate may be further subjected to the step of polishing the surface of the mother plate to control the surface roughness. The controlled surface roughness of the surface of the mother plate is thus transferred to the metal electrodeposition layer surface obtained by electrodeposition. The polishing can be performed on one side or both sides of the base plate as necessary.

Control of the roughness of the surface of the mother plate may be applied to any suitable mechanical, chemical or mechanical chemical polishing apparatus known in the art. Examples thereof include mechanical polishing such as polishing, chemical polishing such as etching, and chemical mechanical polishing such as a chemical mechanical polishing (CMP) method mainly used in semiconductor processes. In the production of Fe-Ni alloy foil using a pole, the quality of the Fe-Ni alloy foil tends to be largely influenced by the surface roughness. For example, the electrodeposited layer electrodeposited to the mother plate transfers the surface roughness of the mother plate, so that the Fe-Ni alloy foil obtained by transferring the poor surface roughness of the mother plate is free from electrical shorts and defects when used as an electrical, electronic and / or device material. It may cause. Therefore, it is preferable to adjust the surface roughness with respect to a mother board suitably according to the usage of the obtained Fe-Ni alloy foil, and it is although it does not specifically limit, For example, when using it for the use of the material for solar cell substrates, it is 200 The substrate surface can be evenly and smoothly polished to have a surface roughness of less than or equal to nm.

Furthermore, the mother plate may further include a mother plate washing step for removing impurities, etc. on the surface of the mother plate as needed before the electrodeposition process. The mother-plate washing is not particularly limited and can be carried out by a method generally known in the art. Although not limited to this, it can wash | clean, for example using acidic solution or water. The acidic solution can be any acidic solution generally known for use in substrate cleaning. Thereafter, high pressure air, hot gas may be injected or the base plate may be heated to further dry as necessary.

Such base plates are continuously supplied into the horizontal electroforming cell and are supplied in a constant direction. In this case, the 'electro-casting cell' refers to an electrolytic solution supplied onto a mother plate where metal ions, specifically, iron and nickel ions are electrodeposited on the surface of the mother plate by an electrolytic precipitation reaction to form a Fe-Ni alloy electrodeposition layer. It can be defined as a unit cell. 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.

The present invention is not limited to this in order to continuously supply the mother board, but the mother board wound in the form of a coil can be supplied into the horizontal cell. Furthermore, when all of the mother boards are supplied, the mother board wound in the form of another coil is supplied with Subsequent to the mother plate can be fed 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. At this time, 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. Can increase the production speed.

When the mother plate is supplied into the horizontal cell as described above, the electrolyte is supplied to one side or both sides of the mother plate through the electrolyte supply nozzle, and the electrolyte moves through the horizontal flow path formed by the mother plate and the anode electrode, and thus the cathode of the cathode is applied. 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 shape of the mother plate 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, which causes the flow rate of the electrolyte to gradually decrease, resulting in a decrease in the electrodeposition rate. There exists a problem that the thickness of the metal electrodeposition layer obtained becomes nonuniform. Furthermore, in the case where the oxide film is formed on the drum surface, impurities are introduced into the electrolyte during this process, and thus there is a problem that the management of the electrolyte is not easy.

However, in the case of the horizontal cell, since the flow path is formed horizontally, the electrolyte can be supplied at high speed without a phenomenon that the flow rate of the electrolyte is reduced, thereby increasing the electrodeposition rate of iron and 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 the electrolyte is increased during initial electrodeposition, the electrodeposition layer may come off and electrodeposition may fail.If the electrodeposition layer grows to several micro levels, the adhesion may be improved by the stress generated in the electrodeposition layer, thereby enabling the use of a high speed flow field. It is. On the other hand, it is preferable to supply a fluid supply rate region limited when using a high speed flow field below the flow rate beyond the surface tension between the electrodeposition layer and the mother plate. When the electrolyte is supplied at a flow rate that exceeds the surface tension between the electrodeposited layer and the mother plate, 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, which may cause the electrodeposition layer to peel off. .

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. In this way, the electrodeposition rate of the iron component and the nickel component on the surface of the mother plate can be further increased.

On the other hand, the electrolyte used for electrodeposition can be recovered by electrolyte storage tank again as needed. At this time, the recovered electrolyte is due to the iron and nickel ions consumed by electrodeposition, the iron ions and nickel ions concentration will be lower than the concentration required in the electrodeposition, appropriately supplement the iron ions and nickel ions to a predetermined iron ions and nickel It can be adjusted by ion concentration.

The electrolyte solution is an aqueous solution containing a polyethylene glycol-based surfactant, an iron precursor and a nickel precursor, and as long as the electrolyte solution contains a polyethylene glycol-based surfactant, an iron precursor and a nickel precursor, the composition of the electrolyte is not particularly limited, and is usually used for electroforming. It may be any electrolyte used.

The surfactant is added to control the surface roughness of the Fe—Ni electrodeposition layer formed on the mother plate. The growing metal surface of the electrodeposition layer obtained by electroforming using an electrolyte solution containing no surfactant is very rough and irregular. However, by adding a surfactant to the electrolyte solution, the metal ion components in the electrolyte solution are uniformly dispersed to obtain a uniformly controlled electrodeposition layer with a small degree of surface roughness. Therefore, in the method according to the embodiment of the present invention, the surface on which the Fe-Ni alloy electrodeposition layer formed by using an electrolyte solution containing a surfactant grows (hereinafter, referred to as an 'electrode layer growth surface'), that is, an electrodeposition layer Constant and uniform surface roughness can be imparted to the surface opposite to the surface in contact with the mother plate. That is, the surface of the Fe—Ni electrodeposition layer may be uniformly and uniformly flattened by the surfactant. Specifically, by controlling the surface roughness (Rz) of the Fe—Ni alloy substrate to 0.05 μm to 0.1 μm, a Fe-Ni alloy substrate for solar cells having improved energy efficiency of the solar cell is obtained. If the surface roughness is less than 0.05 μm, the confinement effect, that is, the duration of light staying in the solar cell is shortened, and the effect of increasing efficiency of the solar cell may be insufficient. On the other hand, when the surface roughness is to be controlled to exceed 0.1㎛ is not easy to thin the substrate is not suitable for thin film solar cells. Therefore, it is preferable to control the surface roughness in the range of 0.05 μm to 0.1 μm. In addition, the content of Fe and Ni in the Fe-Ni alloy electrodeposition layer (thin film) obtained by the present invention is not particularly limited,

In order to control the coefficient of thermal expansion of the Fe-Ni alloy substrate to a level similar to the other components constituting the solar cell, for example, 4x10 ^-6 m / K to 12x10 ^-6 m / K, Ni in the Fe-Ni alloy substrate It is preferable that the content of is 34-62 wt%. Specifically, the Fe-Ni alloy substrate may include 34-62 wt% Ni, balance iron, and other unavoidable impurities. 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. These impurities are not specifically mentioned in this specification, as they are known to any person skilled in the art of manufacturing.

The content of the iron precursor, the nickel precursor and the surfactant in the electrolyte is not particularly limited, and the movement speed of the mother plate, the electrolyte supply speed, the thickness of the Fe-Ni alloy substrate, the surface roughness, the coefficient of thermal expansion, and the Fe-Ni alloy substrate It can adjust suitably content of Fe and Ni.

For example, the electrolyte solution is an aqueous solution containing 2g / l to 25g / l of the iron precursor, 40g / l to 60g / l nickel precursor and 0.1g / l to 4.0g / l surfactant, the conductive aid, complexing agent and Other additives generally added to the electrolyte, such as stress relieving agents, may be included in amounts generally used as necessary.

The iron precursor may be at least one selected from the group consisting of, for example, 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. Polyethylene glycol and / or sodium laureth sulfate may be used as the surfactant.

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.

The thickness of the electrodeposition layer (thin film) of the said Fe-Ni alloy is not specifically limited. However, when the thickness of the alloy foil is less than 20 μm, the resulting alloy foil is too thin, so that subsequent handling is not easy, and when it exceeds 70 μm, the economy may be inferior to that of manufacturing the metal foil by rolling. Therefore, it is preferable to grow an alloy electrodeposition layer in the thickness of 20-70 micrometers from the viewpoint of the ease of handling and economics of alloy foil.

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 an electrodeposition layer is formed by electrodepositing iron and nickel on the mother plate, but the Fe—Ni alloy foil may be washed after separating the Fe—Ni alloy electrodeposition layer from the mother plate. Thereafter, if desired, high pressure air or hot gas may be sprayed on the surface of the Fe—Ni alloy electrodeposition layer or the Fe—Ni alloy foil or dried by a method such as heating.

The electrodeposited Fe—Ni alloy electrodeposition layer is separated from the mother board to obtain a Fe—Ni alloy foil used as a solar electric substrate. 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 the electrodeposition layer is formed on both sides of the mother plate, the upper and lower Fe-Ni alloy electrodeposition layer may be separated at the same time, or may be separated by giving a time difference.

The obtained Fe—Ni alloy foil may be exposed to various working process temperatures depending on the intended use. For example, when the alloy foil is processed to a high temperature of 300 ~ 600 ℃, abnormal grain growth occurs to cause the nano-structure microstructure of the Fe-Ni alloy foil changes to the microstructured structure. Such a change in the microstructure due to the growth of abnormal grains may cause a defect in the product during the process of manufacturing the target product by applying the Fe-Ni alloy foil. For example, when an electronic circuit etc. are formed in Fe-Ni alloy foil, it may cause peeling or disconnection of the circuit during a high temperature process. Therefore, when the Fe-Ni alloy foil obtained in the temperature range causing abnormal grain growth is used, the Fe-Ni alloy foil obtained by separating the Fe-Ni electrodeposition layer from the Fe-Ni electrodeposition layer or the mother plate arbitrarily as needed, It is preferable to prevent the change of the microstructure during the process by heat-treating and changing the microstructure of the microstructure in advance.

The heat treatment conditions described above may vary depending on the target microstructure, but are not particularly limited, but it is preferable that the heat treatment is optionally performed at a temperature of 300 to 600 ° C. In this case, in order to prevent oxidation of the surface during heat treatment, it is preferable to use an inert gas atmosphere such as nitrogen and argon, and induction heating, direct heating, contact heating, etc. may be used as the heat treatment method. It is preferable to heat-treat the Fe-Ni alloy layer before separating from the mother board, or to heat-treat the Fe-Ni alloy foil from which the Fe-Ni alloy layer was separated from the mother board, and to heat-treat the Fe-Ni alloy foil from an efficiency point of view.

The obtained Fe-Ni alloy foil can be wound up and can be cut suitably according to the winding amount. Furthermore, the base plate from which the metal layer is separated can also be wound up and reused as the base plate. However, the separated mother plate may have an electrolyte solution 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.

The process conditions and the electrolyte composition in the horizontal electroforming step are not particularly limited and can be performed in a range generally performed in the electroforming and plating processes.

The Fe-Ni alloy substrate for solar cells obtained by the method according to the embodiment of the present invention is 0.05 μm on one surface, specifically, on the surface on which the Fe-Ni alloy electrodeposition layer, which is the opposite surface of the surface in contact with the mother plate, grows during horizontal electroforming. It has a surface roughness Rz of 0.1 micrometer. In this way, the Fe-Ni alloy substrate having a surface roughness (Rz) of 0.05 µm to 0.1 µm on one surface is used as the solar cell substrate, thereby improving the efficiency of the solar cell. Specifically, in the solar cell having a transparent electrode layer on the concave-convex surface having the surface roughness of the Fe—Ni alloy substrate, light incident on the solar cell is diffusely reflected by the concave-convex surface. Meanwhile, the diffused light stays in the solar cell for a long time, so that the efficiency of the light absorbing layer formed on the substrate is increased, thereby improving the efficiency of the solar cell.

The Fe-Ni alloy substrate has the advantage of being lightweight, flexible, inexpensive, and capable of mass production. That is, since not only a certain level of strength and / or hardness is secured but also flexible, cracking or breaking due to physical impact does not easily occur, which is advantageous in terms of securing durability. It also exhibits excellent corrosion resistance. Furthermore, there is an advantage in terms of productivity because the manufacturing cost is low and mass production is possible. Moreover, since it is easily changed into a roll-like form, it is easy to store and to control the size of the substrate to meet the needs of the customer.

The Fe-Ni alloy substrate includes 34 wt% to 62 wt% nickel, balance iron, and other unavoidable impurities, thereby optimizing the coefficient of thermal expansion of the substrate. Since the solar cell has a different resistance to the stress of the substrate or the material laminated thereon according to the change in temperature, the substrate and other materials may crack or break. Therefore, the coefficient of thermal expansion between the materials constituting the solar cell should be controlled to a nearly similar level. In the Fe-Ni alloy substrate containing 34 wt% to 62 wt% nickel, the thermal expansion coefficient is optimized by controlling the nickel content. Specifically, it has a coefficient of thermal expansion of about 4 × 10 ⁻⁶ m / K to about 12 × 10 ⁻⁶ m / K, thus preventing cracking and breaking of the solar cell using the alloy substrate.

Hereinafter, a method of manufacturing a Fe-Ni alloy substrate for a solar cell by a horizontal electroforming method according to an embodiment of the present invention will be described with reference to the horizontal electroforming apparatus of FIG. 1. 1 is not limited to the horizontal electroforming apparatus used for manufacturing a Fe-Ni alloy substrate for solar cells by the horizontal electroforming method according to an embodiment of the present invention as an example of the horizontal electroforming apparatus as FIG.

The horizontal pole device 100 includes a mother plate supply device 10, a horizontal cell 30, an electrolyte supply device and a Fe-Ni alloy foil separator 51.

The mother plate feeding device 10 may include a winding machine for supplying the mother plate 11. The winding machine may be provided in plural to continuously supply the base plate 11, and when the base plate 11 is exhausted in one winding machine, the new base plate 11 may be supplied in another winding machine. Such base plate 11 may comprise a joining device 12, such as welding, for joining the ends of the base plate 11 provided in advance and the tip of the base plate 11 to be provided next, for continuous feeding.

Furthermore, since the electrodeposition layer electrodeposited on the base plate 11 transfers the surface roughness of the base plate 11, it is represented in substantially the same way to the Fe-Ni alloy foil from which the surface roughness of the base plate 11 is obtained. Therefore, the polishing apparatus 13 for providing the appropriate surface roughness to the base plate 11 can be further included as needed. Such a polishing apparatus 13 is not particularly limited, and may include mechanical polishing such as polishing, chemical polishing such as etching, and chemical mechanical polishing such as a CMP method mainly used in semiconductor processes. The chemical polishing, mechanical polishing and chemical mechanical polishing apparatuses may be used alone or in combination thereof.

Impurities may be present on the surface of the mother plate 11, so that 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. Furthermore, a drying apparatus (not shown) for drying the mother plate 11 may be further included as necessary. Drying can be carried out by adding air to a high pressure or by adding a hot gas. Alternatively, the mother plate 11 may be heated.

Horizontal pole apparatus 100 according to an embodiment of the present invention includes a horizontal cell 30 that is separated from the mother plate feeding device (10). In the case of a conventional electroforming apparatus using a drum, there was a problem that foreign matters generated during drum surface polishing to adjust the surface roughness of the drum were mixed in the electrolyte and contaminated the electrolyte. Since it is separated from (10), such a problem 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 the electrolyte and an electrolyte solution containing the electrolyte solution for the electrolytic reaction.

The conductor rolls 31 and 31 'function as a transfer device for transferring the mother plate into the horizontal cell 30 and discharging it from the horizontal cell 30, as well as the mother plate 11 and the current supply device. By connecting the cathode power source (33), an electrolytic precipitation reaction is performed such that iron and nickel ions are deposited on the mother plate by an electrolytic reaction between the anode electrode 32 and the mother plate 11. These conductor rolls 31 and 31 'contact the two edges of the base plate 11 in the width direction to transfer the base plate 11 into the horizontal cell 30 and also discharge it from the horizontal cell 30. .

In one embodiment of the present invention, since a flexible conductive mother board is used as the mother board 11, a drooping phenomenon may occur when passing through the horizontal cell 30, in which case the mother board 11 and the anode The spacing of the electrodes 32 may vary to cause a difference in current density, and therefore, a Fe—Ni alloy foil 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 is spaced apart from the base plate 11 passing through the horizontal cell 30 by a predetermined interval. Since the anode electrode 32 is spaced apart from the base plate 11, a flow path through which an electrolyte is supplied and distributed therebetween is formed. In addition, as described above, the anode electrode 32 causes an electrolytic reaction to electrolytically deposit iron and nickel ions in the electrolyte onto the mother plate 11 by the action of the mother plate 11 as a cathode electrode. When the electrolyte is supplied at high speed, the electrodeposition speed of iron and nickel ions to the surface of the base plate 11 can be increased. In the case of electroforming using a conventional drum cell, the flow path forms a curvature so that the flow rate of the electrolyte is gradually decreased. Therefore, there was a problem that the electrodeposition speed is slowed. However, as described above, the flow path of the electrolyte is formed in a plane, thereby minimizing the decrease in the speed of the flow field with respect to the supply of the electrolyte.

The anode electrode 32 may be spaced apart from each other on the upper and lower surfaces of the mother plate 11 so that an electrolytic precipitation reaction of metal occurs on both sides of the mother plate 11. By doing this, the production amount of the Fe-Ni alloy foil can be increased.

The electrolyte solution is composed of, for example, at least one iron precursor of 2g / l to 25g / l selected from the group consisting of iron sulfate, iron chloride, iron nitrate and iron sulfamate, nickel sulfate, nickel chloride, nickel nitrate and nickel sulfamate 40 g / l to 60 g / l of at least one kind of nickel precursor selected from the group, 0.1 g / l to 4.0 g / l of at least one surfactant selected from the group consisting of polyethylene glycol and sodium laureth sulfate, and conducting aids, complexing agents and stresses Other additives such as emollients and the like may be included in amounts generally used as required.

Meanwhile, the current supply device 33 supplies negative current and positive current to the conductor rolls 31, 31 'and the anode electrode 32, respectively. As applicable to the present invention without limitation, a detailed description thereof will be omitted.

The electrolyte supply device includes an electrolyte storage tank 34 for storing and accommodating an electrolyte solution and an electrolyte supply nozzle 38 for supplying an electrolyte solution to the surface of the base plate 11, and supplying an electrolyte solution from the electrolyte storage tank 34 through an electrolyte supply pipe. It is moved to the nozzle 38. 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.

The electrolyte reservoir 34 is an electrolyte heater 35 for heating the electrolyte, an electrolyte filter 36 for removing impurities such as sludge contained in the electrolyte, an electrolyte pump 37 for supplying the electrolyte to a horizontal cell, and the like. It may further include as needed.

On the other hand, the current density may be relatively low at both edges in the width direction as compared to the center of the base plate 11, the amount of electrodeposited Fe-Ni alloy deposited on the edge of the base plate 11 is less Fe-Ni alloy The thickness of the foil becomes relatively thin and the overall uniform thickness of the Fe-Ni alloy foil may not be obtained. In this case, when the obtained Fe—Ni alloy layer is separated from the base plate 11, the edge of the Fe—Ni alloy foil may be torn and a defect may occur. In order to make the Fe-Ni alloy foil 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 thickness variation by preventing the precipitation of the Fe-Ni alloy at the edge portion of the mother plate, and for this purpose, an edge mask (not shown) may be provided so that electrolyte is not supplied to the edge of the mother plate. have. By providing such an edge mask, electrodeposition of the thin Fe-Ni alloy 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 of electrodeposits are electrodeposited. Since the electrolyte supplied to the contact with the base plate 11 for a longer time can be obtained the effect of the secondary electrodeposition of a relatively large amount of electrodeposition 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 electrodeposited layer is peeled from the mother plate 11 during movement by being disposed in series in the mother plate 11 traveling direction. 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 advances at a higher speed while reducing the electrodeposition amount through one cell, thereby improving the productivity of the Fe-Ni alloy foil. Can be improved. Electrodeposition conditions and electrolyte solutions in the plurality of horizontal cells 30 may be the same or different.

The base plate 11 in which the electrodeposition layer is formed as described above is discharged through the outlet-side conductor roll 31 ', and after discharge, the Fe-Ni alloy foil separating device 51 is used to remove the Fe- from the base plate 11. The Ni alloy layer is separated to obtain the Fe—Ni alloy foil 50. Since the Fe-Ni alloy foil 50 is bonded by the surface tension to the base plate 11 having an oxide film formed on the surface thereof, the Fe-Ni alloy foil 50 may be separated by a difference in shear force between the Fe-Ni alloy foil 50 and the base plate 11. . Therefore, the Fe-Ni alloy foil separator 51 is preferably capable of imparting a shear stress for separating the Fe-Ni alloy foil 50 from the base plate 11, for example, a plurality of rollers Can be installed. In addition, due to the difference in the moving speed of the Fe-Ni alloy foil 50 and the mother plate 11, it is possible to separate the upper and lower Fe-Ni alloy foil 50 at the same time or at a time difference.

The surface roughness (Rz) of the Fe-Ni alloy thin film, specifically, in the horizontal electroforming, the surface of the Fe-Ni alloy electrodeposition layer, which is the opposite surface of the contact with the mother plate grows of 0.05㎛ to 0.1㎛ It has a surface roughness Rz. In addition, the thermal expansion coefficient of the Fe-Ni alloy thin film is 4x10 ^-6 m / K to 12x10 ^-6 m / K, the thickness of the Fe-Ni alloy thin film may be 20㎛ to 70㎛.

On the other hand, the horizontal pole device 100 is a Fe-Ni alloy foil winding device 55 and the mother board winding device 72 winding the Fe-Ni alloy foil 50 and the mother board 11 separated from the base plate 11 It may include. For example, it can be wound up to a cylindrical winder. According to the winding amount of the winder, it may be wound in an appropriate amount, cut and wound around another winder. Fe-Ni alloy foil cutting device 54 and the mother plate cutting device 71 as necessary for the cutting, it is more preferable to cut at the bonding portion of the base plate (11).

In addition, the horizontal pole device 100 according to an embodiment of the present invention is discharged from the horizontal cell 30 as necessary before or after separating the Fe-Ni alloy foil 50 or after the Fe- as necessary The aftertreatment apparatus of Ni alloy foil can be further included as needed. Examples of such a post-treatment apparatus include a post-cleaning apparatus 52, a drying apparatus (not shown), a heat treatment apparatus 53, and the like.

The cleaning device 52 is a device for removing by using an acid solution such as hydrochloric acid or sulfuric acid diluted with an electrolyte and / or foreign substances that may exist on the surface of the Fe-Ni alloy foil 50, such as a high pressure spray Ordinary devices can be used. The drying apparatus may be an injector that injects air at high pressure or injects high temperature gas to remove the washing liquid present on the surface of the Fe-Ni alloy foil 50 after washing, or may be a heating apparatus for drying by heating. Can be.

The heat treatment apparatus 53 is for preventing a change in the microstructure due to abnormal grain growth when the Fe—Ni electrodeposition layer or the Fe—Ni thin film 50 formed by electrodeposition is processed by a high temperature process. Fe-Ni electrodeposition layer or Fe-Ni alloy foil 50 may be heat-treated at 350 ~ 600 ℃, it is preferable to use an inert gas atmosphere, such as nitrogen, argon gas atmosphere to prevent surface oxidation during heat treatment. In addition, as the heat treatment method, induction heating, direct heating, contact heating may be used.

As described above, the method for manufacturing the Fe-Ni 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 device is not limited to these embodiments, and 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 are not intended to limit the invention.

Example 1

The surface roughness (Rz) was polished to 200 nm by supermirror processing, and the STS 304 steel sheet washed with water through the substrate feeding device 10 and the conductor roll 31 of the horizontal pole device having the configuration as shown in FIG. The anode electrode 32 of the main cell was supplied at a feed rate of 50 mpm (meter per minute). The electrolyte was supplied to the Reynolds number (Re) 1000 through the electrolyte nozzle 38 in the electrolyte flow path formed by the anode 32 and the mother plate 10 of the pole cell. The electrolyte solution includes FeCl ₂ · 4H ₂ O 10 g / L, NiCl ₂ · 6H ₂ O 55 g / L, polyethylene glycol 3.0 g / L and H ₃ BO ₃ 25 g / L, pH 1.5 ~ 3.5, An aqueous solution having a temperature of 55 ° C. was used. An electrolytic reaction was carried out at a current density of 5 A / dm 2 to form a Fe—Ni electrodeposition layer having a thickness of 40 μm on both sides of the mother plate. The formed Fe-Ni electrodeposited layer was separated to obtain an Fe-Ni alloy substrate. The thin film thus obtained was sufficiently washed with water and then dried. The prepared Fe-Ni alloy substrate contains 42wt% nickel, residual iron and other unavoidable impurities, and the coefficient of thermal expansion is 5.6 x 10 ^-6 m / K, the surface roughness of the opposite side of the electrodeposition surface (electrode layer growth surface) ( Rz) was 0.06 micrometer.

The obtained Fe—Ni alloy substrate, stainless steel substrate (thickness 40 μm, surface roughness (Rz) 402 nm, manufactured by rolling method), and a-solar cell device / Al ₂ O ₃ -SiO ₂ buffer layer / An Al / TCO / p-Si: H / i-Si: H / n-Si: H / TCO layer was sequentially formed to fabricate a specimen device.

The physical properties of the Fe-Ni alloy substrate element and the organic substrate element obtained in the present embodiment are shown in Table 1 by solar field measurement.

Fe-Ni alloy substrate Glass substrate Jsc (mA / cm 2) 15.98 16.3 Voc (V) 0.789 0.795 FF. (%) 55.3 56 Eff. (%) 7.14 7.22

As shown in Table 1, it can be seen that the solar substrate device manufactured using the Fe-Ni alloy substrate manufactured by the method according to the present invention exhibits similar performance to the solar substrate device manufactured using the conventional glass substrate. .

On the other hand, using the Fe-Ni alloy substrate according to the present invention and the stainless steel substrate manufactured by the conventional rolling method, the specimen element as described above was produced 20 times. In this case, the device using the Fe-Ni alloy substrate did not generate an electrical short, but the device using the stainless steel substrate generated an electrical short due to the high surface roughness at 18 of 20 times. Therefore, it was confirmed that by using the Fe-Ni alloy substrate substrate prepared by the method according to the present invention, a good solar cell device can be manufactured without an electric short circuit.

10: Feeder 11: Feeder
12: bonding apparatus 13: polishing apparatus
14: electric cleaning device 30: horizontal cell
31, 31 ': Conductor roll 32: anode electrode
33: current supply device 34: electrolyte storage tank
35: Electrolyte heater 36: Electrolyte filter
37: Electrolyte pump 38: Electrolyte nozzle
50: Fe-Ni alloy foil 51: peeling roll
52: Post-cleaning device 53: Heat treatment device
54: Fe-Ni alloy foil cutting device 55: Fe-Ni alloy foil winding device
71: Cutting board cutting device 72: Flattening device
100: horizontal pole

Claims (4)

At least one surfactant selected from the group consisting of 2g / l to 25g / l of iron precursor, 40g / l to 60g / l of nickel precursor and sodium laureth sulfate on one or both sides of the reusable conductive base plate horizontally fed in a constant direction supplying an electrolyte comprising g / l to 4.0 g / l;
Applying an electric current to the conductive base plate serving as a cathode and an anode electrode provided spaced apart from one or both surfaces of the conductive base plate such that iron and nickel are electrodeposited on the conductive base plate; And
And separating an alloy electrodeposition layer of iron and nickel formed by electrodepositing iron and nickel to obtain an alloy foil of iron and nickel, wherein the alloy substrate of iron and nickel is used for a solar cell.
The method of claim 1, 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 A method for producing an alloy substrate of iron and nickel, which is at least one selected from and used for solar cells.
The method of claim 1, wherein the Fe-Ni alloy substrate for solar cells has an uneven surface having a surface roughness (Rz) of 0.05 µm to 0.1 µm, and an alloy substrate of iron and nickel used for solar cells.
The method of claim 1, wherein the Fe—Ni alloy substrate contains 34 wt% to 62 wt% nickel, balance iron, and other unavoidable impurities, and the iron and nickel alloy substrate is used for a solar cell.

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