Copper electroplating solution for photovoltaic cell, preparation method and electroplating method

Abstract

The invention belongs to the field of photovoltaic cell manufacturing, and particularly relates to a copper electroplating solution for a photovoltaic cell, a preparation method and an electroplating method, and the copper electroplating solution comprises the following components according to the concentration: 50-150 g / L of sulfuric acid, 30-120 g / L of copper sulfate pentahydrate, 10-50 mg / L of chloride ions, 0.2-5 mg / L of an accelerator, 0.2-5 g / L of a wetting agent, 5-50 mg / L of a leveling agent and the balance of deionized water. By adding the inorganic leveling agent, the matching use effect is excellent, the electroplated copper grid line is uniform, flat, bright and compact, the quality of the grid line is remarkably improved, and the influence on the environment in the use process is relatively small.

Description

Technical Field

[0001] The invention belongs to the field of photovoltaic cell manufacturing, and in particular relates to a copper electroplating solution for photovoltaic cells, a preparation method and an electroplating method. Background Art

[0002] With the rapid development of the photovoltaic industry, reducing the amount of silver has become an important means of reducing the cost of solar cells, including copper electroplating technology. Photovoltaic silver paste is an important material in the manufacture of photovoltaic cells, which directly affects the photoelectric conversion efficiency of photovoltaic cells and the output power of photovoltaic modules. In the photovoltaic industry, the high cost of photovoltaic silver paste has always been a pain point in the industry. Silver paste accounts for about 35% of the non-silicon cost of photovoltaic cells, which is the largest non-silicon cost of photovoltaic cells. Using low-value metals to replace expensive photovoltaic silver paste is an urgent need in the photovoltaic industry.

[0003] Electroplating copper is a process of electrolysis in which copper ions combine with electrons to form copper grid lines plated on the surface of the seed layer in a plating solution containing copper ions. The purpose of reducing the consumption of silver paste is achieved by electroplating copper grid lines. When electroplating or depositing copper grid lines, due to the influence of various factors, such as uneven current distribution, changes in plating solution composition, and slight differences in the substrate surface, the thickness, width or shape of the copper grid lines may be uneven. This unevenness may not only reduce the electrical conductivity of the copper grid lines, but may also cause signal transmission problems in the circuit, and even cause the failure of the entire circuit. Therefore, the uniformity and quality of the copper grid lines directly affect the performance and reliability of the circuit. However, existing electroplating copper grid lines may have grid line quality problems, such as broken grids, unevenness, etc. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a copper electroplating solution, a preparation method and an electroplating method for photovoltaic cells. By adding an inorganic leveling agent and matching the solutions of each component, the electroplated copper grid lines are uniform, flat, bright and dense, the quality of the grid lines is significantly improved, and the impact on the environment during use is relatively small.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A copper electroplating solution for photovoltaic cells, the copper electroplating solution comprising the following components according to concentration: sulfuric acid: 50-150 g / L, copper sulfate pentahydrate: 30-120 g / L, chloride ion: 10-50 mg / L, accelerator: 0.2-5 mg / L, wetting agent: 0.2-5 g / L, leveler: 5-50 mg / L, and the balance is deionized water;

[0007] The accelerator is any one of sodium dithiopropane sulfonate, sodium mercaptopropane sulfonate, and thioacetic acid acetyl alkyl ester;

[0008] The wetting agent is any one of polyethylene glycol, polypropylene glycol, and fatty alcohol polyoxyethylene ether;

[0009] The leveling agent is any one of potassium iodide, potassium bromide and ammonium bromide;

[0010] The chloride ions are introduced by any one of concentrated hydrochloric acid, sodium chloride and potassium chloride.

[0011] Another object of the present invention is to provide a method for preparing a copper electroplating solution for photovoltaic cells, comprising the following steps:

[0012] 1) Take an appropriate amount of deionized water, stir continuously, and add sulfuric acid to obtain solution A;

[0013] 2) Continue stirring solution A and add copper sulfate pentahydrate to obtain solution B;

[0014] 3) Chloride ions, accelerator, wetting agent and leveling agent are added to solution B in sequence, and stirred until mixed to obtain a copper electroplating solution for photovoltaic cells.

[0015] Preferably, in step 3), the stirring temperature is 20-50° C. and the stirring time is 30-60 min.

[0016] Another object of the present invention is to provide an electroplating method for photovoltaic cells using a copper electroplating solution, wherein the photovoltaic cells are placed in an electroplating tank containing the copper electroplating solution, and the cells are passed through the electroplating tank at a uniform speed, thereby forming copper grid lines on the cells.

[0017] Preferably, the working temperature of the copper electroplating solution is 20-50° C., the working time is 2-20 min, and the current density is 5-50 ASD.

[0018] Preferably, the copper grid line has a thickness of 5-50 μm.

[0019] Beneficial effects:

[0020] The photovoltaic cell copper electroplating solution provided by the present invention has excellent effect by adding an inorganic leveling agent and using it in combination with various component solutions. The electroplated copper grid lines are uniform, flat, bright and dense, the quality of the grid lines is significantly improved, and the impact on the environment during use is relatively small. The solution is simple and convenient to obtain and prepare. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of electroplating copper grid lines of a cell according to Example 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of the copper grid lines of the electroplated solar cell according to embodiment 2 of the present invention.

[0023] Figure 3This is a schematic diagram of the copper grid lines of the electroplated solar cell in Example 3 of the present invention.

[0024] Figure 4 This is a schematic diagram of the electroplating of copper grid lines of a cell in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0025] The following is a detailed description through specific embodiments in conjunction with the accompanying drawings.

[0026] The copper electroplating solution for photovoltaic cells provided by the present invention comprises the following components according to concentration: sulfuric acid: 50-150 g / L, copper sulfate pentahydrate: 30-120 g / L, chloride ion: 10-50 mg / L, accelerator: 0.2-5 mg / L, wetting agent: 0.2-5 g / L, leveler: 5-50 mg / L, and the balance is deionized water;

[0027] The accelerator is any one of sodium dithiopropane sulfonate, sodium mercaptopropane sulfonate, and thioacetic acid acetyl alkyl ester;

[0028] The wetting agent is any one of polyethylene glycol, polypropylene glycol, and fatty alcohol polyoxyethylene ether;

[0029] The leveling agent is any one of potassium iodide, potassium bromide and ammonium bromide;

[0030] Chloride ions are introduced by any one of concentrated hydrochloric acid, sodium chloride, and potassium chloride.

[0031] A method for preparing a copper electroplating solution for photovoltaic cells according to an embodiment of the present invention comprises the following steps:

[0032] 1) Take an appropriate amount of deionized water, stir continuously, and add sulfuric acid to obtain solution A;

[0033] 2) Continue stirring solution A and add copper sulfate pentahydrate to obtain solution B;

[0034] 3) Chloride ions, accelerator, wetting agent and leveling agent are added to solution B in sequence, and stirred until uniformly mixed to obtain a copper electroplating solution for photovoltaic cells; the stirring temperature is 20-50° C., and the stirring time is 30-60 min.

[0035] The embodiment of the present invention provides an electroplating method for a photovoltaic cell electroplating copper solution, wherein the photovoltaic cell is placed in an electroplating tank filled with the electroplating copper solution, a transmission system is turned on, and the cell passes through the electroplating tank at a uniform speed, thereby forming copper grid lines on the cell, and the thickness of the formed copper grid lines is 5-50 μm; wherein the working temperature of the electroplating copper solution is 20-50° C., the working time is 2-20 min, and the current density is 5-50 ASD.

[0036] In the embodiment of the present invention, a semi-finished crystalline silicon cell is placed in the copper electroplating solution, and the transmission system is turned on to allow the semi-finished cell to pass through the electroplating tank at a uniform speed, thereby forming copper grid lines on the cell to obtain a silicon solar cell.

[0037] Example 1

[0038] A copper electroplating solution for photovoltaic cells and an electroplating method thereof, wherein the copper electroplating solution comprises the following components according to concentration: sulfuric acid: 50 g / L, copper sulfate pentahydrate: 30 g / L, hydrochloric acid: 20 mg / L, sodium 2-propanesulfonate: 1 mg / L, polyethylene glycol: 1 g / L, potassium iodide: 15 mg / L, and the balance is deionized water;

[0039] A method for preparing a copper electroplating solution for photovoltaic cells comprises the following steps:

[0040] 1) Take an appropriate amount of deionized water, stir continuously, and add sulfuric acid to obtain solution A;

[0041] 2) Continue stirring solution A and add copper sulfate pentahydrate to obtain solution B;

[0042] 3) Add hydrochloric acid, sodium 2-propanesulfonate, polyethylene glycol and potassium iodide to solution B in sequence, stir until mixed, and obtain a copper electroplating solution for photovoltaic cells; the stirring temperature is 30° C. and the stirring time is 60 min.

[0043] A method for electroplating a copper electroplating solution for photovoltaic cells, wherein a semi-finished crystalline silicon cell is placed in the copper electroplating solution, a transmission system is turned on, and the semi-finished cell passes through an electroplating tank at a uniform speed, thereby forming copper grid lines on the cell to obtain a silicon solar cell; wherein the working temperature of the copper electroplating solution is 30°C, the working time is 5 minutes, and the current density is 50ASD.

[0044] Example 1 The electroplated copper grid line is as follows Figure 1 As shown, the copper grid lines are uniform, flat, bright and dense, and the thickness of the copper grid lines is 20 μm.

[0045] Example 2

[0046] A copper electroplating solution for photovoltaic cells and an electroplating method thereof, wherein the copper electroplating solution comprises the following components according to concentration: sulfuric acid: 150 g / L, copper sulfate pentahydrate: 120 g / L, potassium chloride: 50 mg / L, sodium mercaptopropane sulfonate: 5 mg / L, polypropylene glycol: 5 g / L, ammonium bromide: 50 mg / L, and the balance is deionized water;

[0047] A method for preparing a copper electroplating solution for photovoltaic cells comprises the following steps:

[0048] 1) Take an appropriate amount of deionized water, stir continuously, and add sulfuric acid to obtain solution A;

[0049] 2) Continue stirring solution A and add copper sulfate pentahydrate to obtain solution B;

[0050] 3) Potassium chloride, sodium mercaptopropane sulfonate, polypropylene glycol and ammonium bromide are added to solution B in sequence, and stirred until uniformly mixed to obtain a copper electroplating solution for photovoltaic cells; the stirring temperature is 20° C., and the stirring time is 30 min.

[0051] A method for electroplating a copper solution for photovoltaic cells, wherein a semi-finished crystalline silicon cell is placed in the copper electroplating solution, a transmission system is turned on, and the semi-finished cell passes through an electroplating tank at a uniform speed, thereby forming copper grid lines on the cell to obtain a silicon solar cell; wherein the working temperature of the copper electroplating solution is 20°C, the working time is 20 minutes, and the current density is 20ASD.

[0052] Example 2 The electroplated copper grid line is as follows Figure 2 As shown, the copper grid lines are uniform, flat, bright and dense, and the thickness of the copper grid lines is 50 μm.

[0053] Example 3

[0054] A copper electroplating solution for photovoltaic cells and an electroplating method thereof, wherein the copper electroplating solution comprises the following components according to concentration: sulfuric acid: 80 g / L, copper sulfate pentahydrate: 70 g / L, sodium chloride: 10 mg / L, thioacetic acid acetylalkyl ester: 0.2 mg / L, fatty alcohol polyoxyethylene ether: 0.2 g / L, potassium bromide: 5 mg / L, and the balance is deionized water;

[0055] A method for preparing a copper electroplating solution for photovoltaic cells comprises the following steps:

[0056] 1) Take an appropriate amount of deionized water, stir continuously, and add sulfuric acid to obtain solution A;

[0057] 2) Continue stirring solution A and add copper sulfate pentahydrate to obtain solution B;

[0058] 3) Sodium chloride, thioacetic acid acetyl alkyl ester, fatty alcohol polyoxyethylene ether and potassium bromide are added to solution B in sequence, and stirred until mixed to obtain a copper electroplating solution for photovoltaic cells; the stirring temperature is 50° C. and the stirring time is 45 min.

[0059] A method for electroplating a copper solution for photovoltaic cells, wherein a semi-finished crystalline silicon cell is placed in the copper electroplating solution, a transmission system is turned on, and the semi-finished cell passes through an electroplating tank at a uniform speed, thereby forming copper grid lines on the cell to obtain a silicon solar cell; wherein the working temperature of the copper electroplating solution is 50°C, the working time is 2 minutes, and the current density is 5ASD.

[0060] Example 3 The electroplated copper grid line is as follows Figure 3 As shown, the copper grid lines are uniform, flat, bright and dense, and the thickness of the copper grid lines is 5 μm.

[0061] Comparative Example 1

[0062] A copper electroplating solution for photovoltaic cells and an electroplating method thereof, wherein the copper electroplating solution comprises the following components according to concentration: sulfuric acid: 150 g / L, copper sulfate pentahydrate: 120 g / L, potassium chloride: 50 mg / L, sodium mercaptopropane sulfonate: 5 mg / L, polypropylene glycol: 5 g / L, and the balance is deionized water;

[0063] A method for preparing a copper electroplating solution for photovoltaic cells comprises the following steps:

[0064] 1) Take an appropriate amount of deionized water, stir continuously, and add sulfuric acid to obtain solution A;

[0065] 2) Continue stirring solution A and add copper sulfate pentahydrate to obtain solution B;

[0066] 3) Potassium chloride, sodium mercaptopropane sulfonate and polypropylene glycol are added to solution B in sequence, and stirred until uniformly mixed to obtain a copper electroplating solution for photovoltaic cells; the stirring temperature is 20° C., and the stirring time is 30 min.

[0067] A method for electroplating a copper electroplating solution for photovoltaic cells, wherein a semi-finished crystalline silicon cell is placed in the copper electroplating solution, a transmission system is turned on, and the semi-finished cell passes through the electroplating tank at a uniform speed, thereby forming a copper grid line on the cell to obtain a silicon solar cell; wherein the working temperature of the electroplating copper solution is 20°C, the working time is 20 minutes, and the current density is 20ASD

[0068] Comparative Example 1 lacks a leveling agent compared to Example 2. The copper grid line electroplated in Comparative Example 1 is as follows: Figure 4 As shown, the copper grid line is uneven and flat, with obvious defects on the surface, and the thickness of the copper grid line is 45μm.

[0069] Table 1 Evaluation results of coating quality of Examples 1-3 and Comparative Example 1

[0070] Example 1 Example 2 Example 3 Comparative Example 1 Plating thickness (μm) 20 50 5 45 Coating uniformity Uniform Uniform Uniform Uneven

[0071] According to Table 1 and the attached Figure 1-3 It can be seen that the appearance of the coating after electroplating with the photovoltaic cell copper electroplating solution provided by the present invention is uniform, dense and bright, while the appearance of the coating after electroplating with the photovoltaic cell copper electroplating solution of Comparative Example 1 is not uniform, and there are problems such as plating leakage. It can be seen that the photovoltaic cell copper electroplating solution provided by the present invention has excellent effect by adding an inorganic leveling agent and matching the solutions of each component. The copper grid lines electroplated are uniform, flat, bright and dense, the quality of the grid lines is significantly improved, and the impact on the environment during use is relatively small.

[0072] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the above embodiments describe the present invention in detail, relevant technical personnel in the field should understand that the present invention can be modified or equivalently replaced, but any modification and partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A copper electroplating solution for photovoltaic cells, characterized in that: The electroplating copper solution includes the following components according to concentration: sulfuric acid: 50-150g / L, copper sulfate pentahydrate: 30-120g / L, chloride ion: 10-50mg / L, accelerator: 0.2-5mg / L, wetting agent: 0.2-5g / L, leveler: 5-50mg / L, and the balance is deionized water; The accelerator is any one of sodium dithiopropane sulfonate, sodium mercaptopropane sulfonate, and thioacetic acid acetyl alkyl ester; The wetting agent is any one of polyethylene glycol, polypropylene glycol, and fatty alcohol polyoxyethylene ether; The leveling agent is any one of potassium iodide, potassium bromide and ammonium bromide; The chloride ions are introduced by any one of concentrated hydrochloric acid, sodium chloride and potassium chloride.

2. The method for preparing a copper electroplating solution for photovoltaic cells according to claim 1, characterized in that: The following steps are involved: 1) Take an appropriate amount of deionized water, stir continuously, and add sulfuric acid to obtain solution A; 2) Continue stirring solution A and add copper sulfate pentahydrate to obtain solution B; 3) Chloride ions, accelerator, wetting agent and leveling agent are added to solution B in sequence, and stirred until mixed to obtain a copper electroplating solution for photovoltaic cells.

3. The method for preparing a copper electroplating solution for photovoltaic cells according to claim 2, characterized in that: In the step 3), the stirring temperature is 20-50° C. and the stirring time is 30-60 min.

4. The electroplating method for a photovoltaic cell copper electroplating solution according to any one of claims 1 to 3, characterized in that: The photovoltaic cell is placed in an electroplating tank containing the electroplating copper solution, and the cell passes through the electroplating tank at a uniform speed, thereby forming copper grid lines on the cell.

5. The electroplating method for photovoltaic cell copper electroplating solution according to claim 4, characterized in that: The working temperature of the copper electroplating solution is 20-50° C., the working time is 2-20 min, and the current density is 5-50 ASD.

6. The electroplating method for photovoltaic cell copper electroplating solution according to claim 4, characterized in that: The copper grid line has a thickness of 5-50 μm.

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