Solar cell electrode preparation process

Abstract

The invention discloses a solar cell electrode preparation process, which comprises the following steps of S1, printing a grid line, printing a mixed slurry of a catalytic activity factor and a polymer slurry on a cell by using a silk-screen printing template to form a seed layer, and enabling a cell region which is not covered by the seed layer to be a hollow region; s2, electroplating copper: electroplating the seed layer of the battery piece to generate an electroplating copper layer; s3, deplating copper: deplating copper ions on the upper surface and the lower surface of the battery piece; s4, electroplating tin: electroplating metal tin on the upper surface and the lower surface of the battery piece; and S5, detinning: forming an anode by the battery piece and the roller in contact with the battery piece, and deplating tin ions on the upper surface and the lower surface of the battery piece. The preparation process is simple and easy to operate, expensive equipment and expensive raw material silver paste do not need to be used, and the cost of manufacturing the battery electrode is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of solar cell electrodes, in particular to a solar cell electrode preparation process. Background Art

[0002] With the development of economy and the progress of society, people have put forward higher and higher requirements for energy, and the search for new energy has become an urgent issue facing mankind. Photovoltaic power generation is a technology that uses the photovoltaic effect of semiconductor interfaces to directly convert light energy into electrical energy. The key component of this technology is solar cells. After being connected in series and packaged for protection, solar cells can form large-area solar cell modules. At present, the new energy industry represented by solar power generation is developing rapidly and is moving forward at a foreseeable faster speed. How to further reduce the manufacturing cost of solar cells has become an important issue in the industry, and the cost of solar cell electrodes accounts for the largest proportion of the entire non-silicon cost. At present, the preparation of solar cell electrodes adopts the method of screen printing silver paste. The price of screen printing equipment including silver paste is very high and difficult to reduce. Summary of the invention

[0003] In order to overcome the above disadvantages, one of the purposes of the present invention is to provide a solar cell electrode preparation process, which reduces the manufacturing cost of solar cells by replacing screen-printed silver paste with electroplated electrodes. In order to achieve the above purpose, the technical solution adopted by the present invention is: a solar cell electrode preparation process, comprising the following steps:.

[0004] S1. Printing grid lines: using a screen printing template to print a mixed slurry of catalytic active factors and polymer slurry on the cell to form a seed layer, and the cell area not covered by the seed layer is a hollow area; S2. Copper electroplating: A horizontal electroplating method is adopted. The battery cell is placed horizontally and immersed in the electroplating solution through a transmission mechanism. The battery cell is driven by the rotation of the roller in the tank to carry out horizontal chain transmission of the battery cell. The battery cell and the roller in contact with it form a cathode, and a copper electroplating layer is generated on the seed layer of the battery cell by electroplating; S3, copper stripping: the battery cell and the roller in contact with it form an anode to strip the copper ions on the upper and lower surfaces of the battery cell; S4, electroplating tin: using the horizontal electroplating method, electroplating metal tin on the upper and lower surfaces of the battery cell; S5, tin stripping: the battery cell and the roller in contact with it form an anode to strip the tin ions on the upper and lower surfaces of the battery cell.

[0005] Furthermore, in S1, the catalytic activity factor includes copper hydroxyphosphate; and the polymer slurry includes acrylonitrile-butadiene-styrene copolymer.

[0006] Furthermore, in S1, the seed layer has a thickness of 100-200 nm.

[0007] Furthermore, in S2, the roller in contact with the battery cell is a titanium alloy roller, and the speed of the transmission mechanism for transmitting the battery cell is 1.5-2.5 M / min.

[0008] Furthermore, in S2, the thickness of the electroplated copper layer located on the surface of the seed layer is 0.2-0.3 mm.

[0009] Further, in S2, the electroplating solution includes copper sulfate, ethylenediamine and water, wherein the concentration of copper sulfate is 250 g / L, and the concentration of ethylenediamine is 135 g / L.

[0010] Further, in S2, the transmission mechanism includes an anode plate group, the anode plate group includes an upper anode plate and a lower anode plate, during electroplating, the battery cell is located between the upper anode plate and the lower anode plate, the transmission mechanism also includes a plurality of roller groups arranged in a horizontal direction, each roller group includes two rollers arranged upper and lower, during electroplating, the two rollers can clamp the battery cell and move.

[0011] Furthermore, in S3, the temperature of the stripping solution used for copper stripping is 30-50°C.

[0012] Furthermore, in S4, the plating solution formula for electroplating tin is: 25-30 g / L tin sulfate, 15-18 g / L 2-imidazolidinone, 15-20 g / L sodium rosinate, and 15-20 g / L 2-methyl-5-nitrobenzenesulfonic acid ammonium.

[0013] Furthermore, in S4, the conditions for electroplating tin are: the plating solution temperature is 40-50°C, the current density is 6-9A / dm 2 .

[0014] The beneficial effects of the present invention are: The present invention utilizes the good adhesion of the seed layer and the electroplated copper layer, and uses the methods of electroplating copper and stripping copper to electroplate a copper layer on the seed layer. Similarly, a tin layer is formed on the electroplated copper layer. The method for preparing the electrode (seed layer, electroplated copper layer, electroplated tin layer) is simple and easy to operate. It does not require the use of expensive equipment and expensive raw material silver paste, thereby reducing the cost of manufacturing the electrode. The metal layer is formed in the printed area by the electroplating process, and the metal layer is removed in the hollow area by the stripping process. Therefore, the preparation of the electrode can be completed without the use of a mask layer, which reduces the preparation steps and reduces the preparation cost. The electrode is prepared by the electroplating method, so that the resistance of the electrode is less than the silver grid line formed by traditional screen printing, thereby reducing the power loss of the battery cell itself. BRIEF DESCRIPTION OF THE DRAWINGS The drawings constituting a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 This is a schematic diagram of the printed grid lines of the present invention; Figure 2 This is a schematic diagram of copper electroplating of the present invention; Figure 3 It is a schematic diagram of copper stripping of the present invention; Figure 4 This is a schematic diagram of electrotinning of the present invention; Figure 5 It is a schematic diagram of tin stripping of the present invention.

[0017] Among them: 1. Battery cell; 2. TCO layer; 3. Seed layer; 4. Hollow area; 5. Electroplated copper layer; 6. Electroplated tin layer. DETAILED DESCRIPTION

[0018] In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0019] Except as shown in the operating examples or otherwise indicated, all numbers used in the specification and claims to indicate the amount of ingredients, physicochemical properties, etc. are understood to be adjusted by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters listed in the above specification and the attached claims are approximate values, and those skilled in the art can use the teachings disclosed herein to seek to obtain the desired properties and appropriately change these approximate values. The use of numerical ranges expressed as endpoints includes all numbers within the range and any range within the range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5, etc.

[0020] A solar cell electrode preparation process, specifically comprising the following steps: S1, printed grid lines See attached Figure 1 As shown, firstly, a mixed slurry of catalytic active factors and polymer slurry is printed on the TCO layer 2 of the cell 1 using a screen printing template to form a seed layer 3. The surface of the cell has a printing area and a hollow area 4 by screen printing. The surface of the cell covered with the seed layer 3 is the printing area, and the surface of the cell not covered with the seed layer 3 is the hollow area 4. Catalytic active factors are substances that can promote the rate of chemical reactions but do not participate in the reaction itself. Catalytic active factors include copper hydroxyphosphate. The polymer slurry is a mixture of polymer materials and solvents, and the polymer material is acrylonitrile-butadiene-styrene copolymer.

[0021] The thickness of the seed layer is 100~200nm. By introducing an extremely thin seed layer 3 between the electroplated metal and the transparent conductive film (TCO layer 2), the contact and adhesion performance of the electrode can be improved. S2, electroplated copper See attached Figure 2 As shown, the horizontal electroplating method is adopted. The battery cell is placed horizontally and immersed in the electroplating solution through a transmission mechanism. The battery cell is driven by the rotation of the rollers in the tank for horizontal chain transmission. One side of the roller is a titanium alloy roller, and the battery keeps contact with it to form a cathode. Under the action of a DC power supply, the copper ions in the reduction solution are reduced to copper metal to complete the copper electroplating of the battery cell. The thickness of the electroplated copper layer 5 located directly above the seed layer 3 is 0.2~0.3mm.

[0022] The electroplating solution includes copper sulfate, ethylenediamine and water, wherein the concentration of copper sulfate is 250 g / L and the concentration of ethylenediamine is 135 g / L.

[0023] The transmission mechanism includes an anode plate group, which includes an upper anode plate and a lower anode plate. During electroplating, the battery cell is located between the upper anode plate and the lower anode plate, and the spacing between two adjacent roller groups is less than the minimum length of the battery cell. In this way, during electroplating, the battery cell can contact at least two roller groups to ensure that the rollers can transmit the battery cell. The transmission speed of the transmission mechanism is 1.5-2.5M / min.

[0024] The transmission mechanism includes multiple roller groups arranged in the horizontal direction, and each roller group includes two rollers arranged one above the other. After multiple battery cells are arranged along the length direction of the rollers, they are sent into the first roller group together. The surface of the roller body has a certain degree of roughness. As the rollers rotate, the battery cells can move horizontally to the next roller group. When the battery cells come out of the last roller group, the electroplating of the battery cells is completed.

[0025] The two surfaces of the cell before electroplating have a printed area and a hollow area 4. The seed layer 3 in the printed area has better adhesion to the electroplated copper, so the main area of ​​electroplated copper is above the seed layer. Of course, a small amount of electroplated copper will also adhere to the hollow area, but the amount of electroplated copper attached to the hollow area is much smaller than the amount of electroplated copper attached to the printed area.

[0026] The purpose of using multiple roller groups in the present invention is that if only one or two roller groups are used for electroplating, the thickness of the copper plating layer deposited in the grid line area may be uneven and fail to meet the requirements of the electroplating process. By moving the battery cell in the horizontal direction (i.e., using a continuous electroplating method), copper ions are always deposited in the grid line area, which can prevent the plating thickness in the grid line area from being uneven or failing to meet the process requirements.

[0027] S3, copper stripping See attached Figure 3 As shown, a horizontal deplating method is adopted, the battery cell is immersed in the deplating liquid during the transmission of the roller, and the battery cell is driven by the rotation of the roller to be horizontally chain-transmitted in the tank body, and then the principle of pulse power supply is used to perform intermittent deplating on some areas of the battery cell.

[0028] In the electroplating structure, the roller is connected to the cathode to electroplate the battery cell, and the roller can be connected to the anode to de-plate the copper ions deposited in the hollow area. At the same time, the copper ions on the surface of the roller are de-plated to maintain the flatness of the roller surface to prevent the battery cell from being crushed due to unevenness, which is beneficial to reducing the fragmentation rate of the battery cell.

[0029] Since the adhesion between the electroplated layer and the cell in the hollow area is less than that between the seed layer and the electroplated layer, the deplating effect of the metal copper in the hollow area is better than that of the metal copper in the printed area during the deplating process. Therefore, through the copper electroplating and deplating process, a plated metal copper layer can be formed on the surface of the seed layer, while there is no metal copper layer in the hollow area, and the electroplating process of the metal copper grid line is completed without mask coverage.

[0030] The anode and cathode are immersed in the deplating solution and the temperature is maintained at 30-50°C. The voltage between the anode and cathode is kept constant at 1.0-1.3V and the battery cell is moved under the action of a roller. After the battery cell is removed from the deplating solution, it is washed with deionized water and dried to complete the electrochemical deplating.

[0031] Regeneration of deplating solution: When the copper content in the deplating solution is higher than 10g / L, cool the deplating solution to 1~5℃ and let it stand for 12h. After filtering out the precipitated crystals, heat the deplating solution to 40℃, and then dissolve 0.5~2.0g of composite antioxidant, 0.3~1.0g of sodium thiosulfate and 10~20g of thiourea in the deplating solution in sequence and stir evenly to complete the regeneration of the deplating solution.

[0032] S4, electroplating tin See attached Figure 4 As shown, a horizontal electroplating method is adopted, the battery cell is placed horizontally and then immersed in the electroplating solution through a conveying structure, and the battery cell is horizontally chain-transmitted in the tank body by the rotation of the roller, one side of which is usually a conductive material, and the battery keeps contact with it to form a cathode. Under the action of a DC power supply, the tin ions in the solution are reduced to an electroplated tin layer, and the precipitation of tin is completed, forming an electroplated tin layer 6 on the electroplated copper layer 5.

[0033] The thickness of the electroplated tin layer is 0.1-20um.

[0034] The formula of the electroplating solution is: 25~30g / L of tin sulfate, 15~18g / L of 2-imidazolidinone, 15~20g / L of sodium rosin acid, and 15~20g / L of 2-methyl-5-nitrobenzenesulfonic acid ammonium.

[0035] The electroplating conditions are: the plating solution temperature is 40~50℃, the current density is 6-9A / dm 2 .

[0036] S5, tin stripping See attached Figure 5 As shown, a horizontal electroplating method is adopted, the battery cell is immersed in the plating solution during the transmission of the roller, and the battery cell is driven by the rotation of the roller to be horizontally chain-transmitted in the tank body, and then the principle of pulse power supply is used to perform intermittent deplating on some areas of the battery cell to complete the final finishing.

[0037] In the electroplating structure, the roller is connected to the cathode to electroplate the battery cell, and the roller can be connected to the anode to de-plate the tin ions deposited in the hollow area 4, and at the same time, the tin ions on the surface of the roller are de-plated to maintain the flatness of the roller surface to prevent the battery cell from being crushed due to unevenness, which is beneficial to reduce the fragmentation rate of the battery cell. The principle is the same as that of copper electroplating and copper stripping. Through tin electroplating and tin stripping, a tin-plated layer 6 can be formed on the surface of the copper-plated layer 5, while there is no tin-plated layer in the hollow area 4.

[0038] Specifically, the anode and cathode are immersed in the deplating solution and the temperature is maintained at 30-50°C, the voltage between the anode and cathode is kept constant at 1.0-1.3V, and the battery cell is moved under the action of a roller. After the battery cell is removed from the deplating solution, it is washed with deionized water and dried to complete the electrochemical deplating.

[0039] Example The following examples describe the disclosure of the present invention in more detail, and these examples are intended for illustrative purposes only, as various modifications and variations within the scope of the disclosure of the present invention will be apparent to those skilled in the art. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0040] Example 1 S1, printed grid lines First, a mixed slurry of catalytic active factors and polymer slurry is printed on the cell using a screen printing template to form a printed layer. The printed layer has a printed area and a hollow area. The surface of the cell covered with the printed layer is the printed area, and the hollow area is not covered with the printed layer. The catalytic active factor is a substance that can promote the rate of chemical reactions but does not participate in the reaction itself. The catalytic active factor includes copper hydroxyphosphate. The polymer slurry is a mixture of a polymer material and a solvent. The polymer material is acrylonitrile-butadiene-styrene copolymer. The thickness of the seed layer is 100nm.

[0041] S2, electroplated copper The horizontal electroplating method is adopted. The battery cell is placed horizontally and immersed in the electroplating solution through the transmission mechanism. The battery cell is driven by the rotation of the roller in the tank for horizontal chain transmission. One side of the roller is usually a conductive material, specifically a titanium alloy roller, and the battery is in contact with it to form a cathode. Under the action of a DC power supply, the copper ions in the reduction solution are reduced to copper metal to complete the copper electroplating of the battery cell. The thickness of the electroplated copper is 0.2mm. The electroplating solution includes copper sulfate, ethylenediamine and water, wherein the concentration of copper sulfate is 250g / L, and the concentration of ethylenediamine is 135g / L. The transmission speed of the transmission mechanism is 1.5M / min.

[0042] S3, copper stripping The horizontal deplating method is adopted. The battery cell is immersed in the deplating liquid during the transmission of the roller. The battery cell is driven by the rotation of the roller to be horizontally chain-transmitted in the tank body. Then, the principle of pulse power supply is used to perform intermittent deplating on some areas of the battery cell.

[0043] In the electroplating structure, the roller is connected to the cathode to electroplate the battery cell, and the roller can be connected to the anode to de-plate the copper ions deposited in the hollow area 4, and at the same time, the copper ions on the surface of the roller are de-plated to maintain the flatness of the roller surface to prevent the battery cell from being crushed due to unevenness, which is beneficial to reducing the fragmentation rate of the battery cell.

[0044] The anode and cathode are immersed in the deplating solution and the temperature is maintained at 30°C. The voltage between the anode and cathode is kept constant at 1.0V and the battery cell is moved under the action of a roller. After the battery cell is removed from the deplating solution, it is washed with deionized water and dried to complete the electrochemical deplating.

[0045] S4, electroplating tin The horizontal electroplating method is adopted. The battery cell is placed horizontally and immersed in the electroplating solution through the conveying structure. The battery cell is driven by the rotation of the roller in the tank to be horizontally chain-transmitted. One side of the roller is usually a conductive material, and the battery keeps contact with it to form a cathode. Under the action of the DC power supply, the tin ions in the solution are reduced to an electroplated tin layer to complete the precipitation of tin. The thickness of the electroplated tin layer is 0.1um.

[0046] The formula of the electroplating solution is: 25g / L tin sulfate, 18g / L 2-imidazolidinone, 15g / L sodium rosinate, and 20g / L 2-methyl-5-nitrobenzenesulfonic acid ammonium.

[0047] The electroplating conditions are: electroplating solution temperature 40°C, current density 9A / dm 2 .

[0048] S5, tin stripping The horizontal electroplating method is adopted. The battery cells are immersed in the plating solution during the transmission of the rollers. The battery cells are driven by the rotation of the rollers to be horizontally chain-transmitted in the tank. Then, the principle of pulse power supply is used to perform intermittent deplating on some areas of the battery cells to complete the final finishing.

[0049] In the electroplating structure, the roller is connected to the cathode to electroplate the battery cell, and the roller can be connected to the anode to de-plate the tin ions deposited in the hollow area 4, and at the same time, the tin ions on the surface of the roller are de-plated to maintain the flatness of the roller surface to prevent the battery cell from being crushed due to unevenness, which is beneficial to reducing the fragmentation rate of the battery cell.

[0050] The anode and cathode are immersed in the deplating solution and the temperature is maintained at 30°C. The voltage between the anode and cathode is kept constant at 1.0V and the battery cell is moved under the action of a roller. After the battery cell is removed from the deplating solution, it is washed with deionized water and dried to complete the electrochemical deplating.

[0051] Example 2 S1, printed grid lines First, a mixed slurry of catalytic active factors and polymer slurry is printed on the cell using a screen printing template to form a printed layer, which has a printed area and a hollow area. The surface of the cell covered with the printed layer is the printed area, and the hollow area is not covered with the printed layer. The catalytic active factors include copper hydroxyphosphate. The polymer slurry is a mixture of a polymer material and a solvent, and the polymer material is acrylonitrile-butadiene-styrene copolymer. The thickness of the seed layer is 200nm.

[0052] S2, electroplated copper The horizontal electroplating method is adopted. The battery cell is placed horizontally and immersed in the electroplating solution through the transmission mechanism. The battery cell is driven by the rotation of the roller in the tank for horizontal chain transmission. One side of the roller is usually a conductive material, specifically a titanium alloy roller, and the battery is in contact with it to form a cathode. Under the action of a DC power supply, the copper ions in the reduction solution are reduced to copper metal to complete the copper electroplating of the battery cell. The thickness of the electroplated copper is 0.3mm. The electroplating solution includes copper sulfate, ethylenediamine and water, wherein the concentration of copper sulfate is 250g / L, and the concentration of ethylenediamine is 135g / L. The transmission speed of the transmission mechanism is 2.5M / min.

[0053] S3, copper stripping The horizontal deplating method is adopted. The battery cell is immersed in the deplating liquid during the transmission of the roller. The battery cell is driven by the rotation of the roller to be horizontally chain-transmitted in the tank body. Then, the principle of pulse power supply is used to perform intermittent deplating on some areas of the battery cell.

[0054] In the electroplating structure, the roller is connected to the cathode to electroplate the battery cell, and the roller can be connected to the anode to de-plate the copper ions deposited in the hollow area 4, and at the same time, the copper ions on the surface of the roller are de-plated to maintain the flatness of the roller surface to prevent the battery cell from being crushed due to unevenness, which is beneficial to reducing the fragmentation rate of the battery cell.

[0055] Specifically, the anode and cathode are immersed in the deplating solution and the temperature is maintained at 50°C. The voltage between the anode and cathode is kept constant at 1.3V and the battery cell is moved under the action of a roller. After the battery cell is removed from the deplating solution, it is washed with deionized water and dried to complete the electrochemical deplating.

[0056] S4, electroplating tin The horizontal electroplating method is adopted. The battery cell is placed horizontally and immersed in the electroplating solution through the conveying structure. The battery cell is driven by the rotation of the roller in the tank to be horizontally chain-transported. One side of the roller is usually a conductive material, and the battery keeps contact with it to form a cathode. Under the action of the DC power supply, the tin ions in the solution are reduced to an electroplated tin layer to complete the precipitation of tin. The thickness of the electroplated tin layer is 20um.

[0057] The formula of the electroplating solution is: 30g / L tin sulfate, 15g / L 2-imidazolidinone, 20g / L sodium rosin acid, and 15g / L 2-methyl-5-nitrobenzenesulfonic acid ammonium.

[0058] The electroplating conditions are: electroplating solution temperature 50°C, current density 6A / dm 2 .

[0059] S5, tin stripping The horizontal electroplating method is adopted. The battery cells are immersed in the plating solution during the transmission of the rollers. The battery cells are driven by the rotation of the rollers to be horizontally chain-transmitted in the tank. Then, the principle of pulse power supply is used to perform intermittent deplating on some areas of the battery cells to complete the final finishing.

[0060] In the electroplating structure, the roller is connected to the cathode to electroplate the battery cell, and the roller can be connected to the anode to de-plate the tin ions deposited in the hollow area 4, and at the same time, the tin ions on the surface of the roller are de-plated to maintain the flatness of the roller surface to prevent the battery cell from being crushed due to unevenness, which is beneficial to reducing the fragmentation rate of the battery cell.

[0061] Specifically, the anode and cathode are immersed in the deplating solution and the temperature is maintained at 50°C. The voltage between the anode and cathode is kept constant at 1.3V and the battery cell is moved under the action of a roller. After the battery cell is removed from the deplating solution, it is washed with deionized water and dried to complete the electrochemical deplating.

[0062] Example 3 S1, printed grid lines First, a mixed slurry of catalytic active factors and polymer slurry is printed on the cell using a screen printing template to form a printed layer. The printed layer has a printed area and a hollow area. The surface of the cell covered with the printed layer is the printed area, and the hollow area is not covered with the printed layer. The catalytic active factor is a substance that can promote the rate of chemical reactions but does not participate in the reaction itself. The catalytic active factor includes copper hydroxyphosphate. The polymer slurry is a mixture of a polymer material and a solvent. The polymer material is acrylonitrile-butadiene-styrene copolymer. The thickness of the seed layer is 150nm.

[0063] S2, electroplated copper The horizontal electroplating method is adopted. The battery cell is placed horizontally and immersed in the electroplating solution through the transmission mechanism. The battery cell is driven by the rotation of the roller in the tank for horizontal chain transmission. One side of the roller is usually a conductive material, specifically a titanium alloy roller, and the battery is in contact with it to form a cathode. Under the action of a DC power supply, the copper ions in the reduction solution are reduced to copper metal to complete the copper electroplating of the battery cell. The thickness of the electroplated copper layer is 0.25mm. The electroplating solution includes copper sulfate, ethylenediamine and water, wherein the concentration of copper sulfate is 250g / L, and the concentration of ethylenediamine is 135g / L. The transmission speed of the transmission mechanism is 2.0M / min.

[0064] S3, copper stripping The horizontal deplating method is adopted. The battery cell is immersed in the deplating liquid during the transmission of the roller. The battery cell is driven by the rotation of the roller to be horizontally chain-transmitted in the tank body. Then, the principle of pulse power supply is used to perform intermittent deplating on some areas of the battery cell.

[0065] In the electroplating structure, the roller is connected to the cathode to electroplate the battery cell, and the roller can be connected to the anode to de-plate the copper ions deposited in the hollow area 4, and at the same time, the copper ions on the surface of the roller are de-plated to maintain the flatness of the roller surface to prevent the battery cell from being crushed due to unevenness, which is beneficial to reducing the fragmentation rate of the battery cell.

[0066] Specifically, the anode and cathode are immersed in the deplating solution and the temperature is maintained at 40°C. The voltage between the anode and cathode is kept constant at 1.2V and the battery cell is moved under the action of a roller. After the battery cell is removed from the deplating solution, it is washed with deionized water and dried to complete the electrochemical deplating.

[0067] S4, electroplating tin The horizontal electroplating method is adopted. The battery cell is placed horizontally and immersed in the electroplating solution through the conveying structure. The battery cell is driven by the rotation of the roller in the tank to be horizontally chain-transmitted. One side of the roller is usually a conductive material, and the battery keeps contact with it to form a cathode. Under the action of the DC power supply, the tin ions in the solution are reduced to an electroplated tin layer to complete the precipitation of tin. The thickness of the electroplated tin layer is 10um.

[0068] The formula of the plating solution is: 28g / L tin sulfate, 16g / L 2-imidazolidinone, 17g / L sodium rosinate, and 17g / L 2-methyl-5-nitrobenzenesulfonic acid ammonium.

[0069] The electroplating conditions are: electroplating solution temperature 45°C, current density 7A / dm 2 .

[0070] S5, tin stripping The horizontal electroplating method is adopted. The battery cells are immersed in the plating solution during the transmission of the rollers. The battery cells are driven by the rotation of the rollers to be horizontally chain-transmitted in the tank. Then, the principle of pulse power supply is used to perform intermittent deplating on some areas of the battery cells to complete the final finishing.

[0071] In the electroplating structure, the roller is connected to the cathode to electroplate the battery cell, and the roller can be connected to the anode to de-plate the tin ions deposited in the hollow area 4, and at the same time, the tin ions on the surface of the roller are de-plated to maintain the flatness of the roller surface to prevent the battery cell from being crushed due to unevenness, which is beneficial to reducing the fragmentation rate of the battery cell.

[0072] The cathode and anode are immersed in the deplating solution and the temperature is maintained at 40°C. The voltage between the cathode and anode is kept constant at 1.1V and the battery cell is moved under the action of a roller. After the battery cell is removed from the deplating solution, it is washed with deionized water and dried to complete the electrochemical deplating.

[0073] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A solar cell electrode preparation process, characterized in that: The following steps are involved: S1. Printing grid lines: using a screen printing template to print a mixed slurry of catalytic active factors and polymer slurry on the cell to form a seed layer, and the cell area not covered by the seed layer is a hollow area; S2. Copper electroplating: A horizontal electroplating method is adopted. The battery cell is placed horizontally and immersed in the electroplating solution through a transmission mechanism. The battery cell is driven by the rotation of the roller in the tank to carry out horizontal chain transmission of the battery cell. The battery cell and the roller in contact with it form a cathode, and a copper electroplating layer is generated on the seed layer of the battery cell by electroplating; S3, copper stripping: the battery cell and the roller in contact with it form an anode to strip the copper ions on the upper and lower surfaces of the battery cell; S4, electroplating tin: using the horizontal electroplating method, electroplating metal tin on the upper and lower surfaces of the battery cell; S5, tin stripping: the battery cell and the roller in contact with it form an anode to strip the tin ions on the upper and lower surfaces of the battery cell.

2. The solar cell electrode preparation process according to claim 1, characterized in that: In S1, the catalytic active factor includes copper hydroxyphosphate; and the polymer slurry includes acrylonitrile-butadiene-styrene copolymer.

3. The solar cell electrode preparation process according to claim 1, characterized in that: In S1, the seed layer has a thickness of 100-200 nm.

4. The solar cell electrode preparation process according to claim 1, characterized in that: In S2, the roller in contact with the battery cell is a titanium alloy roller, and the speed of the transmission mechanism for transmitting the battery cell is 1.5-2.5 M / min.

5. The solar cell electrode preparation process according to claim 1, characterized in that: In S2, the thickness of the electroplated copper layer located on the surface of the seed layer is 0.2-0.3 mm.

6. The solar cell electrode preparation process according to claim 1, characterized in that: In S2, the electroplating solution includes copper sulfate, ethylenediamine and water, wherein the concentration of copper sulfate is 250 g / L, and the concentration of ethylenediamine is 135 g / L.

7. The process for preparing a solar cell electrode according to claim 1, characterized in that: In S2, the transmission mechanism includes an anode plate group, the anode plate group includes an upper anode plate and a lower anode plate. During electroplating, the battery cell is located between the upper anode plate and the lower anode plate. The transmission mechanism also includes a plurality of roller groups arranged in a horizontal direction, each roller group includes two rollers arranged upper and lower. During electroplating, the two rollers can clamp the battery cell and move it.

8. The process for preparing a solar cell electrode according to claim 1, characterized in that: In S3, the temperature of the stripping solution used for stripping copper is 30-50°C.

9. The solar cell electrode preparation process according to claim 1, characterized in that: In S4, the plating solution formula for electroplating tin is: 25~30g / L tin sulfate, 15~18g / L 2-imidazolidinone, 15~20g / L sodium rosin acid, and 15~20g / L 2-methyl-5-nitrobenzenesulfonic acid ammonium.

10. The solar cell electrode preparation process according to claim 1, characterized in that: In S4, the conditions for electroplating tin are: the plating solution temperature is 40~50℃, the current density is 6-9A / dm 2 .

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