Production equipment and production process for chemically thinning screen printing screen cloth

Abstract

The application discloses a production equipment for a chemical thinning screen cloth for a screen printing screen, which comprises acid tanks, alkali tanks and water tanks which are sequentially arranged and have the same main body structure, an overflow tank is arranged on the outer side of the side wall of the main tank, the overflow tank is communicated with the inside of the main tank through an overflow pipe and a circulating pump, a pure water supply storage box is communicated with the inside of the main tank through a liquid inlet pipe, a liquid discharge device is arranged at the bottom of the main tank, a heating device and a bubbling device are arranged in the inside of the main tank, a mesh plate is arranged in the main tank and covers the top of the heating device and the bubbling device, a screen with the screen cloth is vertically arranged in the main tank and above the mesh plate, the acid tank further comprises an acid supply storage box which is communicated with the inside of the main tank through a liquid inlet pipe, the alkali tank further comprises an alkali supply storage box which is communicated with the inside of the main tank through a liquid inlet pipe, and the water tank further comprises an ultrasonic cleaning device which is arranged in the inside of the main tank. The chemical thinning screen cloth can effectively improve the steel wire diameter, reduce the grid line width in the screen pattern and reduce the consumption of the electrode silver paste in the screen printing.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for producing a screen cloth for a screen printing plate of a solar cell by chemical thinning, and in particular to a production device and a production process. BACKGROUND

[0002] Currently, mainstream PERC, Topcon, HJT and cutting-edge perovskite cells of photovoltaic solar cells all need to use screen printing technology to prepare electrodes. In the screen printing technology, the core process is the plate making process of the screen plate, which is usually composed of a screen frame, a screen cloth and a PI film arranged on the screen cloth. The screen frame is used to carry the entire screen plate and maintain the tension of the screen plate; the screen cloth, as the skeleton and substrate of the screen plate, plays a role in carrying and supporting the PI film, and is a key material in the screen plate manufacturing process, directly affecting the service life of the screen plate and the final screen printing electrode morphology, and thus affecting the amount of electrode paste of the cell and the conversion efficiency.

[0003] With the intensification of competition in the solar cell market, cost reduction and efficiency improvement have become the fundamental for enterprises to survive in the fierce competition. In order to further improve efficiency and reduce cost, the positive electrode grid lines of solar cells must be developed towards ultra-fine and high aspect ratio, which forces the screen plate to develop towards higher mesh and ultra-fine wire diameter.

[0004] However, the material used in batches at the present stage is stainless steel screen cloth with a certain mesh and wire diameter. Due to the limitations of steel wire drawing process, it is difficult to maintain the uniformity and stability of the drawn steel wire after reaching a certain wire diameter limit, and it is not realistic to produce finer wire diameter steel wire through drawing, gradually making it difficult to meet the demand for reducing grid line width. The method of chemical thinning developed later can achieve the purpose of thinning the wire diameter of the screen cloth, but the effect of improving the wire diameter is affected by the production device and production process. SUMMARY

[0005] The purpose of the present application is to provide a production device for chemically thinning a screen cloth for a screen printing plate, and to provide a production process for chemically thinning the screen cloth using the production device, to improve the wire diameter of the screen cloth and obtain a screen cloth with better surface morphology.

[0006] Technical solution: A kind of production equipment of chemical thinning screen printing screen printing screen cloth, including acid tank, alkali tank, water tank arranged in sequence, the main body structure of acid tank, alkali tank, water tank is same, all include main tank, overflow tank, pure water supply storage tank, heating device, bubbling device, liquid discharge device, mesh plate, PLC control device, overflow tank is arranged on the side wall surface outside of main tank, overflow tank is communicated with the inside of main tank by overflow pipe and circulating pump, pure water supply storage tank is communicated with the inside of main tank by inlet pipe, liquid discharge device is arranged at the bottom of main tank, heating device, bubbling device are arranged in the inside of main tank, mesh plate is arranged in main tank and covers the top of heating device, bubbling device, screen printing screen with screen cloth is vertically arranged in main tank and is above mesh plate, acid tank further includes acid supply storage tank communicated with the inside of main tank by inlet pipe, alkali tank further includes alkali supply storage tank communicated with the inside of main tank by inlet pipe, water tank further includes ultrasonic cleaning device arranged in the inside of main tank.

[0007] Further, overflow port is arranged on the side wall surface of main tank above overflow tank.

[0008] Further, ultrasonic cleaning device is installed on the side wall surface of main tank and above mesh plate.

[0009] Further, a plurality of screen printing screens are vertically arranged in main tank and are separated by partition block.

[0010] A production process for chemical thinning of screen cloth using the above production equipment, comprising the following steps:

[0011] S100: vertically place screen printing screen with screen cloth into acid tank, immerse in acidic etching solution, and take out after reaction;

[0012] The acidic etching solution includes sulfuric acid and water, and the addition amount of sulfuric acid is 20-50% of the mass of the acidic etching solution; the temperature of the acidic etching solution is 60-70℃, and the reaction time is 5-20min;

[0013] S200: take out the screen printing screen from the acid tank, vertically place it into the alkali tank, immerse it in the alkaline solution, and remove the residual acidic etching solution;

[0014] The alkaline solution includes alkali and water, and the addition amount of alkali is 10-20% of the mass of the alkaline solution; the temperature of the alkaline solution is 20-30℃, and the reaction time is 1-5min;

[0015] S300: take out the screen printing screen from the alkali tank, vertically place it into the water tank, immerse it in water, and remove the residual alkaline solution;

[0016] The temperature of the water is 20-30℃, and the reaction time is 1-5min.

[0017] Furthermore, in S100: the mass concentration of sulfuric acid is not less than 85%; the acidic corrosion solution also includes a corrosion inhibitor, the amount of which is 0.5 to 1% of the mass of the acidic corrosion solution.

[0018] Beneficial effects: The advantages of this invention are: the chemically thinned mesh fabric produced by the production equipment and process of this application can effectively improve the wire diameter, thereby reducing the width of the grid lines in the screen pattern, and thus reducing the consumption of electrode silver paste in screen printing. The resulting mesh fabric has a uniform wire diameter, and the screen using this mesh fabric has a long lifespan and good printability. The printed grid lines are narrower and higher, with a superior aspect ratio. The battery cells printed with grid lines using this screen have better electrical performance. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention;

[0020] Figure 2 Main view of acid / alkali tank;

[0021] Figure 3 Top view of acid / alkali tank;

[0022] Figure 4 This is the main view of the water tank;

[0023] Figure 5 This is a top view of the water tank;

[0024] Figure 6 This is a schematic diagram showing the connection between the overflow trough and the main trough;

[0025] Figure 7 A schematic diagram of the five locations taken for network cable diameter testing;

[0026] Figure 8 The surface morphology of 520-11 stainless steel mesh before chemical thinning is shown under a microscope.

[0027] Figure 9 The surface morphology of 520-11 stainless steel mesh after chemical thinning in Example 1 is shown under a microscope.

[0028] Figure 10 The printing grid line width morphology of the screen printing plate prepared in Example 1 is shown under a microscope;

[0029] Figure 11 The image shows the line height morphology of the printing grid lines of the screen prepared in Example 1 under a microscope. Detailed Implementation

[0030] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0031] A production equipment for chemically thinned screen printing screen fabric, as shown in the attached document. Figure 1As shown, including acid tank, alkali tank, water tank, Figure 1 From left to right, respectively, the acid tank, alkali tank, water tank.

[0032] The main structure of acid tank, alkali tank, water tank is the same, all including main tank 1, overflow tank 2, pure water supply storage tank 3, heating device 4, bubbling device 5, liquid discharge device 6, mesh plate 7, PLC control device 8, acid tank also includes acid supply storage tank 9, alkali tank also includes alkali supply storage tank 10, water tank also includes ultrasonic cleaning device 11.

[0033] Combined with the drawings Figure 2 , 3 As shown, the structure of the acid tank is illustrated. Combined with the drawings Figure 6 As shown, the upper part of the main tank 1 is provided with an overflow port on the side wall surface thereof, and the overflow tank 2 is arranged outside the side wall surface of the main tank 1 and slightly lower than the overflow port. The overflow tank 2 is connected with the main tank 1 through an overflow pipe 201 to communicate with the inside of the main tank 1. The overflow pipe 201 is connected into the middle part of the main tank 1 and is lower than the position of the overflow tank 2. A circulating pump 202 is arranged on the overflow pipe 201. The pure water supply storage tank 3 is communicated with the inside of the main tank 1 through a liquid inlet pipe 301. The acid supply storage tank 9 is communicated with the inside of the main tank 1 through a liquid inlet pipe 901. The liquid discharge device 6 is arranged outside the main tank 1 at the bottom thereof and is communicated with the inside of the main tank 1 through a liquid discharge pipe 601. The heating device 4 and the bubbling device 5 are arranged inside the main tank 1 and are laid along the inside of the side wall surface to the bottom surface of the main tank. The heating device makes the temperature of the solution in the main tank reach a set temperature. The bubbling device makes the solution in the main tank mix uniformly, contact with the mesh plate and react fully. The mesh plate 7 is arranged inside the main tank and covers the heating device 4 and the bubbling device 5. The screen plate 12 with a mesh cloth is vertically inserted into the main tank 1. The mesh plate 7 supports the screen plate 12 below. A partition block 101 is arranged in the main tank 1. When multiple screen plates 12 are placed in the main tank 1, the screen plates 12 are spaced by the partition block 101.

[0034] The liquid overflow, liquid supply, waste liquid discharge, heating device, bubbling device and the like in the acid tank are controlled by the PLC control device 8.

[0035] Sulfuric acid is provided in the acid supply storage tank and is delivered into the main tank in proportion with the water provided in the pure water supply storage tank to form an acidic etching liquid in the main tank. The acidic etching liquid in the main tank flows to the overflow tank through the overflow port. The acidic etching liquid in the overflow tank is returned to the main tank through the overflow pipe by the circulating pump to realize the circulation of the acidic etching liquid in the inner and outer tanks.

[0036] The difference between the alkali tank and the acid tank is that the acid supply storage tank 9 is replaced by the alkali supply storage tank 10 to provide alkali liquid. The liquid overflow, liquid supply, waste liquid discharge, heating device, bubbling device and the like in the alkali tank are controlled by the PLC control device.

[0037] Combined with the drawingsFigure 4 、 5 As shown in FIG. 6, the difference between the water tank and the acid tank is that there is no acid supply tank 9 and liquid inlet pipe 901, and the ultrasonic cleaning device 11 is arranged inside the main tank 1 and can be mounted on the side wall of the main tank 1 and located above the mesh plate 7. The overflow of liquid in the water tank, liquid supply, waste liquid discharge, heating device, bubbling device, ultrasonic cleaning device, etc. are all controlled by the PLC control device.

[0038] Embodiment 1

[0039] The production process of the screen cloth chemical thinning using the above production equipment specifically includes steps S100-S300.

[0040] S100: Add an acidic etching solution to the acid tank, heat the acidic etching solution to 60°C, then vertically place the screen cloth having a screen plate into the acid tank and immerse it in the acidic etching solution, and take it out after 5 minutes of reaction.

[0041] The acidic etching solution includes sulfuric acid, water, and corrosion inhibitor, the mass concentration of sulfuric acid is 85%, the addition amount of sulfuric acid is 20% of the mass of the acidic etching solution, and the addition amount of the corrosion inhibitor is 0.55% of the mass of the acidic etching solution.

[0042] S200: Add an alkaline solution to the alkali tank, heat the alkaline solution to 25°C, take out the screen plate from the acid tank, vertically place it into the alkali tank, immerse it in the alkaline solution, and remove the residual acidic etching solution after 1 minute of reaction.

[0043] The alkaline solution includes KOH and water, and the addition amount of KOH is 10% of the mass of the alkaline solution.

[0044] S300: Heat the water in the water tank to 25°C, take out the screen plate from the alkali tank, vertically place it into the water tank, immerse it in the water, and clean it for 1 minute to remove the residual alkaline solution.

[0045] Embodiment 2

[0046] The production process of the screen cloth chemical thinning using the above production equipment specifically includes steps S100-S300.

[0047] S100: Add an acidic etching solution to the acid tank, heat the acidic etching solution to 60°C, then vertically place the screen cloth having a screen plate into the acid tank and immerse it in the acidic etching solution, and take it out after 5 minutes of reaction.

[0048] The acidic etching solution includes sulfuric acid, water, and corrosion inhibitor, the mass concentration of sulfuric acid is 85%, the addition amount of sulfuric acid is 30% of the mass of the acidic etching solution, and the addition amount of the corrosion inhibitor is 0.55% of the mass of the acidic etching solution.

[0049] S200: Add an alkaline solution to the alkaline tank and heat the alkaline solution to 25°C. Remove the screen from the acid tank, place it vertically into the alkaline tank, and immerse it in the alkaline solution. React for 2 minutes to remove the residual acidic corrosion solution.

[0050] The alkaline solution consists of KOH and water, with the amount of KOH added being 15% of the mass of the alkaline solution.

[0051] S300: Heat the water in the tank to 25°C, remove the screen from the alkaline tank, place it vertically in the water tank, immerse it in the water, and rinse for 2 minutes to remove residual alkaline solution.

[0052] Example 3

[0053] The difference from Example 2 is that in step S100, the amount of sulfuric acid added is 40% of the mass of the acidic corrosive solution.

[0054] Example 4

[0055] The difference from Example 2 is that in step S100, the amount of sulfuric acid added is 50% of the mass of the acidic corrosive solution.

[0056] Stainless steel mesh fabrics with specifications of 520-11 (520 mesh count, 11 μm wire diameter) and 430-13 (430 mesh count, 13 μm wire diameter) were subjected to chemical thinning treatment as described in Examples 1-4, respectively. Wire diameter tests were performed on the treated and untreated mesh fabrics, as shown in the attached figures. Figure 7 As shown, five points were tested on each piece of mesh, and the average value was taken. The test results are listed in Table 1 and Table 2.

[0057] Table 1. Variation in wire diameter of 520-11 stainless steel mesh

[0058]

[0059]

[0060] Table 2. Variation of wire diameter in 430-13 stainless steel mesh

[0061]

[0062] Appendix Figure 8 , 9 The table shows the surface morphology of 520-11 stainless steel mesh before and after chemical thinning in Example 1. As can be seen from Tables 1 and 2, the wire diameter gradually becomes thinner as the acid concentration in the acidic corrosion solution increases.

[0063] Based on the wire diameter parameters of the mesh fabrics processed and unprocessed in each embodiment, the optimal opening width under the wire diameter parameters is matched to obtain the screen printing plate. The specific parameters of the screen printing plate are listed in Tables 3 and 4.

[0064] Table 3 Screen Parameters (430-13 Stainless Steel Screen Cloth Before Thinning)

[0065] Opening width / μm Film thickness / μm Tension / N Example 1 13 6 14 Example 2 12 6 14 Example 3 11 6 14 Example 4 10 6 14 Comparative Example 14 6 14

[0066] Table 4 Screen Parameters (430-13 Stainless Steel Screen Cloth Before Thinning)

[0067] Opening width / μm Film thickness / μm Tension / N Example 1 15.5 8 17 Example 2 14.5 8 17 Example 3 13 8 17 Example 4 12 8 17 Comparative Example 17 8 17

[0068] The screens were put into the solar cell production line to test the screen life, printing performance, paste consumption and the electrical performance of the cell, etc. The screen life results are listed in Tables 5 and 6, the printed grid linearity data are listed in Tables 7 and 8, the printed grid line width and height are shown in Figs. 5 and 6, respectively, the printed grid paste consumption is listed in Tables 9 and 10, and the electrical performance of the prepared cell is listed in Tables 11 and 12. Figure 10 、 11

[0069] Table 5 Screen Life (430-13 Stainless Steel Screen Cloth Before Thinning)

[0070] Example 1 Example 2 Example 3 Example 4 Comparative Example Lifetime / 104sheets 20 16 12 5 22

[0071] Table 6 Screen Life (430-13 Stainless Steel Screen Cloth Before Thinning)

[0072] Example 1 Example 2 Example 3 Example 4 Comparative Example Lifetime / 104sheets 15 11 10 3 20

[0073] Table 7 Printed Grid Linearity Data (430-13 Stainless Steel Screen Cloth Before Thinning)

[0074] Sample Line width / μm Line height / μm Aspect ratio / % Example 1 22 9.3 42 Example 2 21 8.8 41.9 Example 3 20 8.5 42.5 Example 4 19.3 7.8 40.4 Comparative Example 24 10 41.6

[0075] Table 8 Printed Grid Linearity Data (430-13 Stainless Steel Screen Cloth Before Thinning)

[0076] Sample Line width / μm Line height / μm Aspect ratio / % Example 1 31.3 11 40 Example 2 30 10.7 37.9 Example 3 28 10 40.7 Example 4 27 9.3 40 Comparative Example 32 12 40.6

[0077] Table 9 Printed Grid Paste Consumption (430-13 Stainless Steel Screen Cloth Before Thinning)

[0078] Sample Slurry consumption (g / sheet) Example 1 0.0650 Example 2 0.0627 Example 3 0.0588 Example 4 0.0551 Comparative Example 0.0671

[0079] Table 10 Printed Grid Paste Consumption (430-13 Stainless Steel Screen Cloth Before Thinning)

[0080] Sample Slurry consumption (g / sheet) Example 1 0.0718 Example 2 0.0674 Example 3 0.0647 Example 4 0.0621 Comparative Example 0.0751

[0081] Table 11 Electrical Performance of Prepared Cell (430-13 Stainless Steel Screen Cloth Before Thinning)

[0082] Sample Voc / V Isc / A FF / % Eta / % Example 1 0.6880 13.6779 81.41 23.20 Example 2 0.6886 13.6807 81.40 23.23 Example 3 0.6888 13.6869 81.40 23.25 Example 4 0.6871 13.6862 81.37 23.18 Comparative Example 0.6898 13.6652 81.49 23.19 ​

[0083] Table 12: Electrical performance of prepared battery pieces (430-13 stainless steel screen cloth before thinning)

[0084] Sample Voc / V Isc / A FF / % Eta / % Example 1 0.6866 13.6504 81.48 23.13 Example 2 0.6868 13.6612 81.46 23.14 Example 3 0.6871 13.6691 81.43 23.16 Example 4 0.6869 13.6709 81.38 23.14 Comparative Example 0.6862 13.6475 81.50 23.11

[0085] It can be seen that as the acid concentration in the acid etching solution increases, the wire diameter gradually decreases, the screen plate life after preparation slightly decreases with the decrease of the wire diameter, the width and height of the printed grid lines gradually decrease, and the printing grid line paste consumption also gradually decreases with the decrease of the wire diameter and the opening width. However, the conversion efficiency of the finally prepared battery piece first increases and then decreases, and the conversion efficiency is the highest when the acid concentration is 40%.

[0086] The wire diameter of the 520-11 stainless steel screen cloth is 11 μm, which is the limit of the current steel wire drawing process. It is difficult to maintain the uniformity and stability of the drawn steel wire below 11 μm. The screen cloth thinned by the production equipment and production process of the present application can effectively improve the wire diameter of the steel wire, thereby reducing the line width of the grid lines in the screen plate pattern, and further reducing the electrode silver paste consumption of the screen printing. The prepared screen cloth has uniform wire diameter, high screen plate life, good printing performance, narrow grid line width, high grid line height, superior aspect ratio, and better electrical performance of the battery piece printed with the screen plate.

Claims

1. An apparatus for producing a screen cloth for a chemically thinned screen printing screen, characterized by: The acid tank, the alkali tank and the water tank are sequentially arranged, and the main body structures of the acid tank, the alkali tank and the water tank are the same, each including a main tank, an overflow tank, a pure water supply storage tank, a heating device, a bubbling device, a liquid discharge device, a mesh plate and a PLC control device, the overflow tank is arranged outside the side wall of the main tank, the overflow tank is communicated with the inside of the main tank through an overflow pipe and a circulating pump, the pure water supply storage tank is communicated with the inside of the main tank through a liquid inlet pipe, the liquid discharge device is arranged at the bottom of the main tank, the heating device and the bubbling device are arranged inside the main tank, the mesh plate is arranged inside the main tank and covers the top of the heating device and the bubbling device, a screen plate with a screen cloth is vertically arranged inside the main tank and above the mesh plate, the acid tank further includes an acid supply storage tank communicated with the inside of the main tank through a liquid inlet pipe, the alkali tank further includes an alkali supply storage tank communicated with the inside of the main tank through a liquid inlet pipe, and the water tank further includes an ultrasonic cleaning device arranged inside the main tank.

2. The production apparatus of the chemical-thinned screen cloth for a screen printing plate according to claim 1, characterized by: An overflow port is arranged on the side wall of the main tank above the overflow tank.

3. The production apparatus of the chemical-thinned screen cloth for a screen printing plate according to claim 1, characterized in that: The ultrasonic cleaning device is installed on the side wall of the main tank and above the mesh plate.

4. The production apparatus of the chemical-thinned screen cloth for a screen printing plate according to claim 1, characterized in that: A plurality of screen plates are vertically arranged in the main tank and are separated by a partition block.

5. A production process of chemical thinning of a web using the production apparatus according to claim 1, characterized by The method comprises the following steps: S100: vertically placing a screen plate with a screen cloth into the acid tank, immersing the screen plate in an acid etching solution, and taking out the screen plate after reaction; The acid etching solution comprises sulfuric acid and water, the addition amount of the sulfuric acid is 20-50% of the mass of the acid etching solution, the temperature of the acid etching solution is 60°C, and the reaction time is 5 min; S200: taking out the screen plate from the acid tank, vertically placing the screen plate into the alkali tank, immersing the screen plate in an alkaline solution, and removing residual acid etching solution; The alkaline solution comprises alkali and water, the addition amount of the alkali is 10-15% of the mass of the alkaline solution, the temperature of the alkaline solution is 25°C, and the reaction time is 1-2 min; S300: taking out the screen plate from the alkali tank, vertically placing the screen plate into the water tank, immersing the screen plate in water, and removing residual alkaline solution; The temperature of the water is 25°C, and the reaction time is 1-2 min.

6. The production process according to claim 5, characterized in that: In S100, the mass concentration of the sulfuric acid is 85%, and the acid etching solution further comprises an inhibitor, and the addition amount of the inhibitor is 0.55% of the mass of the acid etching solution.

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