Printing screen for solar cells
By combining mesh and steel plate screen design, especially by adding a second electroplated thickening layer at the end of the steel plate layer, the problem of grid interruption in fine grid printing was solved, achieving stable printing of narrower grids and improving the performance of solar cells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- CHUZHOU JIETAI NEW ENERGY TECH CO LTD
- Filing Date
- 2025-07-15
- Publication Date
- 2026-06-05
AI Technical Summary
Existing screen printing plates and steel plates pose a risk of grid breakage when printing fine grids, especially at the overlap of gradient lines where friction can easily cause grid breakage, making it difficult to meet the printing needs of narrower grids.
The design combines mesh screen printing and steel plate screen printing. The main grid pattern is printed by mesh screen printing, while the fine grid pattern is printed by steel plate screen printing. By adding a second electroplated thickening layer at the end of the steel plate layer and designing a special gradient line overlapping structure, the height difference is reduced and grid breakage is avoided.
This technology reduces the likelihood of grid breakage under narrower grids, improves printing stability and screen lifespan, optimizes grid line width and height, reduces resistance, and increases the fill factor of solar cells.
Smart Images
Figure CN224323723U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of screen printing for solar cells, specifically relating to a printing screen for solar cells. Background Technology
[0002] Solar cells undergo a screen printing process during fabrication. Screen printing uses a screen with openings to allow electrode paste to pass through. The paste is printed onto the cell surface, forming the grid structure of main grids and fine grids (also called sub-grids). After sintering or drying and curing, the desired electrode pattern is obtained. The main grids on the solar cell serve to facilitate subsequent series welding of modules, while the fine grids collect current. The characteristics of the grid structure formed by the screen printing process affect the welding effect during the subsequent module welding process.
[0003] Currently, conventional multi-busbar solar cells are mostly formed using a step-by-step printing method, that is, the main busbar and the fine busbars (sub-busbars) are printed separately. The main busbar printing screen mainly prints the main busbar, pad dots, and harpoon, while the fine busbar printing screen mainly prints the fine busbars, borders, and gradient lines at the connection points. The conventional screen printing sequence is to print the main busbars separately first, then the fine busbars separately. The area where the main busbar and the fine busbar connect (i.e., the end of the fine busbar) is designed with a gradient line area. This gradient line area is screen printed together with the fine busbar, so that the gradient line and the fine busbar lines are printed at the same height. When the module is soldered to the main busbar with solder ribbon, the soldering is performed in the gradient line area, without contacting areas outside the gradient line, otherwise the fine busbars would be melted off, causing defects.
[0004] As the solar energy conversion efficiency of photovoltaic cells continues to improve, the grid width of the cells is becoming increasingly finer, thus placing higher demands on the printing plates used for cell printing. The structure and manufacturing process of traditional screen printing screens have reached their limits, with the minimum grid width being 16. Around m, while ensuring no grid breaks, it is already relatively difficult to print even narrower grids. Moreover, as the printing grid lines become increasingly finer, the traditional screen printing mesh is prone to silver paste blockage at the intersection of warp and weft threads, leading to incomplete printing and broken printing grid lines.
[0005] An expanded metal screen is a type of screen with a 100% aperture ratio. Its substrate is no longer made of woven steel wire, but rather of alloy steel sheets, with printing openings created through electroplating or laser grooving. The expanded metal screen printing area has a 100% aperture ratio, meaning that no steel wire or other similar structures obstruct the printed pattern. Because there is no mesh obstruction in the grooved areas, the transmittance of the printing paste is significantly increased, saving paste consumption. Simultaneously, the width of the grid lines can be optimized, greatly reducing the light-blocking area on the cell surface. Furthermore, the printed grid lines are uniformly flat, with significantly less variation in height compared to traditional screen printing, which can significantly reduce grid line resistance and improve the fill factor of the solar cell.
[0006] Because the steel plate screen is designed without grid lines to block ink penetration, it can achieve narrower grid widths, with a preliminary result of 8-13mm grid widths. m, height 6~12 The stability of printing is important. However, a significant drawback of steel plate screen printing is its inability to print gradient lines. Because fully open steel plates are made of rigid metal, current technology can only achieve uniform, fine grid openings. It cannot yet continuously print gradient lines with varying sizes of openings below the grid lines. This increases the risk of cracking in rigid screen printing, severely impacting its lifespan.
[0007] Furthermore, the width of the fine grid printed on the steel plate is 8~13. m, height 6~12 At the junction of gradient lines, if the fine grid is overlapped on the gradient line, a significant height difference will be created. This height difference greatly increases the risk of the fine grid breaking due to friction. Therefore, it is necessary to rationalize the design and change the overlap contact at the junction of gradient lines to reduce the risk of frictional breakage. Summary of the Invention
[0008] In view of the problems existing in the printing of mesh screens and steel plate screens, this utility model improves the shortcomings of fully open steel plates and provides a printing screen for solar cells that is less prone to grid breakage when printing narrower grids.
[0009] The present invention achieves the aforementioned technical effect through the following technical solution.
[0010] This utility model provides a printing screen for solar cells, including a main grid printing screen and a fine grid printing screen. The main grid printing screen is a mesh screen, including a main grid pattern, a pad pattern, a harpoon pattern, a first gradient line pattern with a first end cap pattern, a second gradient line pattern with a second end cap pattern, and a border line pattern and a chamfer line pattern on the outer side. The fine grid printing screen is a steel plate screen, including a fine grid pattern with multiple fine grid lines segmented. The fine grid lines are formed by a steel plate layer segmented, a first electroplated thickened layer on the upper surface of the steel plate layer, a PI film layer below the steel plate layer, and a second electroplated thickened layer. The second electroplated thickened layer is plated at the end of each segment of the steel plate layer. The PI film layer covers the lower surface of the second electroplated thickened layer and the steel plate layer; the width between two adjacent steel plate layers is smaller than the width between adjacent first electroplated thickened layers on their upper surfaces, and the width between adjacent first electroplated thickened layers is equal to the width between corresponding adjacent second electroplated thickened layers; the intersection of the main grid pattern and the fine grid pattern is connected by a Pad dot pattern, a harpoon pattern, a first end cap pattern of a first gradient line pattern, and a second end cap pattern of a second gradient line pattern; the main grid pattern includes multiple main grid lines extending along a first direction and arranged at equal intervals, and the fine grid lines extend in segments along a second direction and are arranged at equal intervals in the first direction; the second direction intersects with and is perpendicular to the first direction.
[0011] Furthermore, the width W1 between two adjacent steel plate layers is 4~12μm, and the width W2 between adjacent second electroplated thickened layers is 30~300μm.
[0012] Furthermore, the thickness t1 of the steel plate layer is 10~30μm, the thickness t2 of the first electroplated thickening layer is 15~100μm, the thickness t3 of the PI film layer is 2~8μm, the thickness t4 of the second electroplated thickening layer is 3~8μm, and the length L1 of the second electroplated thickening layer is 100~500μm.
[0013] Furthermore, the angle α at the overlap between the main grid pattern and the fine grid pattern is less than 30 degrees, preferably less than 15 degrees.
[0014] Furthermore, each main grid line is connected to the harpoon pattern at both ends. Each main grid line has multiple Pad point patterns and a plurality of first gradient line patterns evenly spaced. Each first gradient line pattern extends along the second direction with each main grid line as its center line, and is thicker in the middle and thinner at both ends. First end cap patterns are located at both ends of the first gradient line patterns and extend along the width direction of the first gradient line patterns. The length L5 of the first gradient line pattern is 0.4~1.3mm, and the width W5 at both ends of the first gradient line pattern is 10~30μm. The width W6 of the first end cap pattern is 10~40μm, and the length L6 is 60~300μm.
[0015] Furthermore, there are multiple second gradient line patterns, which are equally spaced in the middle section of the harpoon pattern. Each second gradient line pattern extends along the second direction with each main grid line as the center line. The second end cap pattern is disposed at both ends of the second gradient line pattern and extends along the width direction of the second gradient line pattern. The length L3 of the second gradient line pattern is 0.4~1.3mm and the width W3 is 20~60μm. The width W4 of the second end cap pattern is 10~40μm and the length L4 is 60~300μm.
[0016] Compared with the prior art, the present invention has the following beneficial effects.
[0017] This invention combines mesh screen printing and steel plate screen printing, leveraging their strengths and avoiding their weaknesses. The mesh screen printing is used to print the main grid pattern, Pad dot pattern, harpoon pattern, first gradient line pattern, second gradient line pattern, border line pattern, and chamfer line pattern. The first gradient line, second gradient line, border line, and chamfer line are all printed with the main grid paste using the mesh screen printing, achieving good overlap with the fine grid printing and reducing the likelihood of grid breakage.
[0018] This utility model's steel stencil prints only fine grids. The opening width and thickness of the steel plate can be designed according to the requirements for the width and height of the fine grids, allowing for the printing of narrower grids. Furthermore, this utility model's steel stencil features a special design in the area where the fine grids overlap with the gradient lines. A second electroplated thickening layer is added to the end of each steel plate layer. The overlap between the main grid and the fine grid forms an angle through the second electroplated thickening layer, avoiding and eliminating grid breakage caused by a large height difference in the overlapping area. With these improvements, this utility model is less prone to grid breakage while still allowing for the printing of narrower grids. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only schematic diagrams of some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 This is a top view of the main grid printing screen of this utility model.
[0021] Figure 2 for Figure 1 A magnified view of part A in the image.
[0022] Figure 3 This is a schematic diagram of the first gradient line pattern and its end cap.
[0023] Figure 4 This is a schematic diagram of the second gradient line pattern and its end cap.
[0024] Figure 5 This is a top view of the fine grid printing screen of this utility model.
[0025] Figure 6 for Figure 5 A magnified view of part B in the image.
[0026] Figure 7 This is a front view of a single fine grid line.
[0027] Figure 8 This is a side view of two adjacent fine grid lines.
[0028] Figure 9 This is a schematic diagram of the grid structure of the solar cell of this utility model.
[0029] Figure 10 Top view of the junction of the main grid line and the fine grid line of this utility model.
[0030] Figure 11 This utility model is a front view of the junction between the main grid line and the fine grid line.
[0031] Figure 12 A front view of the overlap between the main grid line and the fine grid line in the prior art.
[0032] In the diagram: 1-Main grid pattern, 1.1-Main grid line, 2-Pad dot pattern, 3-Harpoon pattern, 4-First gradient line pattern, 4.1-First end cap pattern, 5-Border line pattern, 6-Chamfer line pattern, 7-Fine grid pattern, 7.1-Steel plate layer, 7.2-First electroplated thickened layer, 7.3-PI film layer, 7.4-Second electroplated thickened layer, 7.5-Fine grid line, 8-Second gradient line pattern, 8.1-Second end cap pattern, 9-First positioning point, 10-Second positioning point. Detailed Implementation
[0033] To make the technical problems, technical solutions, and beneficial effects solved by this utility model clearer, the various embodiments of this utility model are described in detail below with reference to the accompanying drawings. It should be understood that the embodiments described herein are only some, not all, of the embodiments of this utility model, and are merely used to explain this utility model and are not intended to limit it. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined and referenced with each other without contradiction.
[0034] The terms "first," "second," etc., used in the specification and claims of this utility model are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, the first object can be one or more.
[0035] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "inner", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0036] In the description of this utility model, "multiple" or "multiple roots" means two or more. "Above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. "Above," "above," and "over" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature.
[0037] This invention provides a solar cell printing screen, including a main grid printing screen and a fine grid printing screen. (Reference) Figures 1-8 The main grid printing screen is a mesh screen, including a main grid pattern 1, a pad pattern 2, a harpoon pattern 3, a first gradient line pattern 4 with a first end cap pattern 4.1, a second gradient line pattern 8 with a second end cap pattern 8.1, and an outer border line pattern 5 and a chamfer line pattern 6. The main grid pattern 1 and the fine grid pattern 7 intersect at the position where they are connected by the first end cap pattern 4.1 of the pad pattern 2, the harpoon pattern 3, the first end cap pattern 4.1 of the first gradient line pattern 4, and the second end cap pattern 8.1 of the second gradient line pattern 8. The main grid pattern 1 includes multiple main grid lines 1.1 extending along a first direction and arranged at equal intervals. The fine grid lines 7.5 extend in segments along a second direction and are arranged at equal intervals along the first direction. The second direction intersects and is perpendicular to the first direction. Figure 2 , Figure 6 In the diagram, the Y direction represents the first direction, and the X direction represents the second direction.
[0038] like Figure 7 , 8 As shown, the fine grid printing screen is a steel plate screen, including a fine grid pattern 7 with multiple fine grid lines 7.5 arranged in segments. The fine grid lines 7.5 are formed by a steel plate layer 7.1 arranged in segments, a first electroplated thickened layer 7.2 located on the upper surface of the steel plate layer 7.1, a PI film layer 7.3 located below the steel plate layer 7.1, and a second electroplated thickened layer 7.4. The second electroplated thickened layer 7.4 is plated at the end of each segment of the steel plate layer 7.1, and the PI film layer 7.3 covers the lower surface of the second electroplated thickened layer 7.4 and the steel plate layer 7.1. The width between two adjacent segments of the steel plate layer 7.1 is smaller than the width between adjacent first electroplated thickened layers 7.2 on their upper surfaces, and the width between adjacent first electroplated thickened layers 7.2 is equal to the width between corresponding adjacent second electroplated thickened layers 7.4.
[0039] In this invention, the PI film layer is the PI film (i.e., polyimide film) commonly used in screen printing for making solar cell electrodes. In screen printing, the PI film is the carrier of the pattern. The edges of the pattern after it is cut are neat and clean, and the line shape is better in printing compared with traditional emulsion screen printing.
[0040] As a specific implementation plan, such as Figure 8 As shown, the width W1 between two adjacent steel plate layers 7.1 is 4~12μm, and the width W2 between adjacent second electroplated thickened layers 7.4 is 30~300μm. Specifically, the width W1 can be 4μm, 5.3μm, 6.1μm, 7μm, 8.3μm, 9μm, 10μm, 10.7μm, 11.2μm, or 12μm, etc.; the width W2 can be 30μm, 42μm, 60μm, 79μm, 93μm, 121μm, 135μm, 154μm, 173μm, 192μm, 216μm, 237μm, 257μm, 288μm, or 300μm, etc.
[0041] As a specific implementation plan, such as Figure 7 As shown, the thickness t1 of the steel plate layer 7.1 is 10~30μm, the thickness t2 of the first electroplated thickened layer 7.2 is 15~100μm, the thickness t3 of the PI film layer 7.3 is 2~8μm, the thickness t4 of the second electroplated thickened layer 7.4 is 3~8μm, and the length L1 of the second electroplated thickened layer 7.4 is 100~500μm. Specifically, thickness t1 can be 10μm, 12μm, 13.7μm, 14.3μm, 15μm, 16.5μm, 18μm, 20.2μm, 21.8μm, 23μm, 24.8μm, 26.2μm, 28.8μm, or 30μm, etc.; thickness t2 can be 15μm, 17.2μm, 19μm, 23.3μm, 26.3μm, 33.5μm, 35μm, 36μm, 42μm, 48μm, 54μm, 62μm, 68μm, 74μm, 82μm, 88μm, 92μm, 96μm, or 100μm, etc.; thickness t3 can be 2μm, 2.3μm, 2.7μm, etc. 3μm, 3.3μm, 3.5μm, 4μm, 4.2μm, 5.3μm, 6.5μm, 7μm, 7.4μm or 8μm, etc.; thickness t4 can be 3μm, 3.3μm, 3.5μm, 3.7μm, 4μm, 4.2μm, 4.5μm, 4.9μm, 5.3μm, 6μm, 6. 6μm, 7μm, 7.4μm or 8μm, etc.; the length L1 can be 100μm, 130μm, 170μm, 200μm, 240μm, 260μm, 275μm, 300μm, 320μm, 360μm, 380μm, 400μm, 430μm, 460μm or 500μm, etc.
[0042] During the printing of the fine grid, the fine grid paste enters through the opening between two adjacent steel plate layers 7.1 and falls onto the solar cell that contacts the bottom of the PI film layer 7.3 to form the fine grid. The width of the fine grid is related to the width W1 between two adjacent steel plate layers 7.1. Due to the influence of ink penetration, the width of the fine grid is not equal to (generally slightly larger than) the width W1 between two adjacent steel plate layers 7.1. The height of the fine grid is related to the height of the steel plate layer 7.1 and the solar cell, that is, the thickness t1 of the steel plate layer 7.1, the thickness t3 of the PI film layer 7.3, and the thickness t4 of the second electroplated thickening layer 7.4. The thickness t2 of the first electroplated thickening layer 7.2 does not affect the printing effect, but only improves the strength of the steel stencil. Since the steel stencil of this utility model only prints fine grid lines, the opening width and thickness of the steel plate layer 7.1 can be designed according to the requirements for the width and height of the fine grid, allowing for the printing of narrower fine grid lines.
[0043] As a specific implementation plan, such as Figure 2 , 3 As shown, each main grid line 1.1 is connected to the harpoon pattern 3 at both ends. Each main grid line 1.1 has multiple Pad point patterns 2 and several first gradient line patterns 4 evenly spaced on it. Each first gradient line pattern 4 extends along the second direction with each main grid line 1.1 as its center line, and is thicker in the middle and thinner at both ends. First end cap patterns 4.1 are located at both ends of the first gradient line patterns 4 and extend along the width direction of the first gradient line patterns 4. The length L5 of the first gradient line pattern 4 is 0.4~1.3mm, and the width W5 at both ends of the first gradient line pattern 4 is 10~30μm. The width W6 of the first end cap pattern 4.1 is 10~40μm, and the length L6 is 60~300μm.
[0044] Specifically, the length L5 can be 0.4mm, 0.45mm, 0.48mm, 0.52mm, 0.57mm, 0.62mm, 0.69mm, 0.71mm, 0.78mm, 0.82mm, 0.9mm, 0.95mm, 1.1mm, 1.2mm, or 1.3mm, etc.; the width W5 can be 10μm, 11.2μm, 13.4μm, 14.8μm, 15.2μm, 16.8μm, 17.5μm, 20μm, 22.4μm, 24μm, 25μm, 28μm, or 30μm, etc.; the width W6 can be... It can be 10μm, 12μm, 14μm, 16.7μm, 18μm, 20μm, 23.2μm, 25μm, 26.7μm, 28μm, 30μm, 32μm, 34.2μm, 36μm, 37.3μm or 40μm, etc.; the length L6 can be 60 μm, 78μm, 85μm, 96μm, 107μm, 118μm, 130μm, 141μm, 155μm, 168μm, 182μm, 209μm, 226μm, 243μm, 251μm, 264μm, 286μm or 300μm, etc.
[0045] As a specific implementation plan, such as Figure 2 , 4 As shown, there are multiple second gradient line patterns 8, which are evenly spaced in the middle section of the harpoon pattern 3. Each second gradient line pattern 8 extends along the second direction with each main grid line 1.1 as its center line. The second end cap pattern 8.1 is located at both ends of the second gradient line pattern 8 and extends along the width direction of the second gradient line pattern 8. The length L3 of the second gradient line pattern 8 is 0.4~1.3mm, and the width W3 is 20~60μm. The width W4 of the second end cap pattern 8.1 is 10~40μm, and the length L4 is 60~300μm.
[0046] Specifically, the length L3 can be 0.4mm, 0.5mm, 0.55mm, 0.6mm, 0.63mm, 0.67mm, 0.71mm, 0.77mm, 0.81mm, 0.86mm, 0.92mm, 0.99mm, 1.05mm, 1.12mm, 1.25mm, or 1.3mm, etc.; the width W3 can be 20μm, 26μm, 32μm, 36μm, 38μm, 40μm, 43μm, 46μm, 50μm, 51μm, 53μm, 55μm, or 60μm, etc.; the width W4 can be 10μm, 20.5μm, 2... The sizes of the nanometers are 1μm, 22.7μm, 23.2μm, 24μm, 24.7μm, 25.8μm, 26.3μm, 27μm, 28.1μm, 29μm, 30μm, 33.2μm, 35μm, 36.3μm, 37.4μm, 38.5μm, or 40μm, etc.; the length L4 can be 60μm, 162μm, 174μm, 186μm, 196μm, 210μm, 227μm, 234μm, 245μm, 251μm, 262μm, 274μm, 286μm, 288μm, 292μm, 296μm, or 300μm, etc.
[0047] The main gate line 1.1 and the fine gate line 7.5 are overlapped by a gradient line 4.1. In the prior art, if the fine gate line 7.5 is overlapped on the gradient line 4.1, such as... Figure 12 As shown, this will create a large height difference, which will greatly increase the risk of the fine grid being broken by friction.
[0048] To avoid and eliminate the problem of broken grid lines in the overlapping area due to height differences, this invention electroplats a second thickened electroplated layer 7.4 at the end of each steel plate layer 7.1, such as... Figure 7 , 8 The description of the related structures shown above. Thus, the overlap between the main grid pattern 1 and the fine grid pattern 7 forms an angle through the second electroplated thickening layer 7.4.
[0049] As one specific implementation scheme, the included angle α at the overlap of the main grid pattern 1 and the fine grid pattern 7 is less than 30 degrees. The overlap between the main grid pattern 1 and the fine grid pattern 7 can be a Pad point pattern 2, a harpoon pattern 3, a first gradient line pattern 4, a first end cap pattern 4.1, a second gradient line pattern 4, or a second end cap pattern 8.1. Figure 11 As shown, the overlap is made through the first end cap pattern 4.1. Depending on the length of the second electroplated thick layer 7.4, the included angle α formed at the overlap of the first end cap pattern 4.1 and the fine grid line 7.5 can be as small as possible, preferably less than 15 degrees. Figure 11In the middle, the angle α between the fine grid line 7.5 and the first end cap pattern 4.1 is 12 degrees. The fine grid line 7.5 is flattened at the overlap with the first end cap pattern 4.1 by the second electroplated thickening layer 7.4, and the original large height difference becomes gentle, thereby avoiding and eliminating the situation of fine grid breakage caused by the large height difference in the overlapping area.
[0050] An angle α will also be formed by overlapping Pad point graphic 2, harpoon graphic 3, first gradient line graphic 4, first end cap graphic 4.1, second gradient line graphic 4, and second end cap graphic 8.1.
[0051] As a specific implementation scheme, the four corners of the main grid printing screen are further provided with first positioning points 9, and the four corners of the fine grid printing screen are further provided with second positioning points 10 corresponding to the first positioning points 9. In this way, the main grid and fine grid after printing the paste are aligned through the first positioning points 9 and the second positioning points 10.
[0052] As one specific implementation, the fine grid lines 7.5 extend in segments along the second direction and are equally spaced in the first direction; the second direction intersects with and is perpendicular to the first direction.
[0053] This invention utilizes a printing screen for printing on solar cells. A main grid printing screen, in conjunction with main grid paste, prints the main grid, pads, harpoons, first gradient lines, border lines, chamfer lines, and second gradient lines on the cell. A fine grid printing screen, in conjunction with fine grid paste, prints the fine grid on the cell. (Reference) Figure 9 The main grid and the fine grid correspond to the main grid line 1.1 of the main grid printing screen and the fine grid line 7.5 of the fine grid printing screen, respectively. The Pad point, harpoon, first gradient line, border line, chamfer line, and second gradient line correspond to the Pad point graphic 2, harpoon graphic 3, first gradient line graphic 4, border line graphic 5, chamfer line graphic 6, and second gradient line graphic 8 of the main grid printing screen. The main grid line 1.1 intersects and is perpendicular to the fine grid line 7.5.
[0054] Main grid graphic 1 is printed with main grid paste. Fine grid graphic 7 is printed with fine grid paste. Pad dot graphic 2, harpoon graphic 3, first gradient line graphic 4, border line graphic 5, chamfer line graphic 6, and second gradient line graphic 8 are printed with main grid paste to correspond to the main grid paste.
[0055] Therefore, the arrangement and relative positions of the fine grid, main grid, Pad point, harpoon, first gradient line, border line, chamfer line, and second gradient line are exactly the same as those of the fine grid line 7.5, main grid line 1.1, Pad point graphic 2, harpoon graphic 3, first gradient line graphic 4, border line graphic 5, chamfer line graphic 6, and second gradient line graphic 8 after the matching printing screen is aligned.
[0056] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the substance and scope of the present invention. Various modifications made by those skilled in the art to the above embodiments after reading this specification are all within the scope of protection of the present invention.
Claims
1. A printing screen for a solar cell, comprising a main grid printing screen and a fine grid printing screen, characterized in that, The main grid printing screen is a mesh screen, including a main grid graphic (1), a Pad dot graphic (2), a harpoon graphic (3), a first gradient line graphic (4) with a first end cap graphic (4.1), a second gradient line graphic (8) with a second end cap graphic (8.1), and a border line graphic (5) and a chamfer line graphic (6) set on the outer side. The fine grid printing screen is a steel plate screen, including a fine grid pattern (7) with multiple fine grid lines (7.5) arranged in segments. The fine grid lines (7.5) are formed by a steel plate layer (7.1) arranged in segments, a first electroplated thickened layer (7.2) located on the upper surface of the steel plate layer (7.1), a PI film layer (7.3) located below the steel plate layer (7.1), and a second electroplated thickened layer (7.4). The second electroplated thickened layer (7.4) is plated at the end of each segment of the steel plate layer (7.1). The PI film layer (7.3) covers the second electroplated thickened layer (7.4) and the lower surface of the steel plate layer (7.1). The width between two adjacent segments of the steel plate layer (7.1) is smaller than the width between adjacent first electroplated thickened layers (7.2) on their upper surfaces. The width between adjacent first electroplated thickened layers (7.2) is equal to the width between corresponding adjacent second electroplated thickened layers (7.4). The main grid pattern (1) and the fine grid pattern (7) are joined at the intersection by the first end cap pattern (4.1) of the Pad point pattern (2), the harpoon pattern (3), the first end cap pattern (4) of the first gradient line pattern (4), and the second end cap pattern (8.1) of the second gradient line pattern (8). The main grid pattern (1) includes multiple main grid lines (1.1) extending along a first direction and arranged at equal intervals, and the fine grid lines (7.5) extending in segments along a second direction and arranged at equal intervals along the first direction; the second direction intersects with and is perpendicular to the first direction.
2. The printing screen for a solar cell according to claim 1, characterized in that, The width W1 between two adjacent steel plate layers (7.1) is 4~12μm, and the width W2 between adjacent second electroplated thickened layers (7.4) is 30~300μm.
3. The printing screen for a solar cell according to claim 1, characterized in that, The thickness t1 of the steel plate layer (7.1) is 10~30μm, the thickness t2 of the first electroplated thickened layer (7.2) is 15~100μm, the thickness t3 of the PI film layer (7.3) is 2~8μm, the thickness t4 of the second electroplated thickened layer (7.4) is 3~8μm, and the length L1 of the second electroplated thickened layer (7.4) is 100~500μm.
4. The printing screen for a solar cell according to claim 1, characterized in that, The angle α at the junction of the main grid pattern (1) and the fine grid pattern (7) is less than 30 degrees.
5. The printing screen for the solar cell according to claim 1, characterized in that, Each main grid line (1.1) is connected to the harpoon pattern (3) at both ends. Each main grid line (1.1) is provided with multiple Pad point patterns (2). Each main grid line (1.1) is provided with several first gradient line patterns (4) at equal intervals. Each first gradient line pattern (4) extends along the second direction with each main grid line (1.1) as the center line and is thick in the middle and thin at both ends. The first end cap pattern (4.1) is provided at both ends of the first gradient line pattern (4) and extends along the width direction of the first gradient line pattern (4). The length L5 of the first gradient line pattern (4) is 0.4~1.3mm, and the width W5 at both ends of the first gradient line pattern (4) is 10~30μm. The width W6 of the first end cap pattern (4.1) is 10~40μm, and the length L6 is 60~300μm.
6. The printing screen for a solar cell according to claim 1, characterized in that, There are multiple second gradient line patterns (8), which are equally spaced in the middle section of the harpoon pattern (3). Each second gradient line pattern (8) extends along the second direction with each main grid line (1.1) as the center line. The second end cap pattern (8.1) is set at both ends of the second gradient line pattern (8) and extends along the width direction of the second gradient line pattern (8). The length L3 of the second gradient line pattern (8) is 0.4~1.3mm and the width W3 is 20~60μm. The width W4 of the second end cap pattern (8.1) is 10~40μm and the length L4 is 60~300μm.
7. The printing screen for a solar cell according to claim 1, characterized in that, The main grid printing screen is provided with first positioning points (9) at its four corners, and the fine grid printing screen is provided with second positioning points (10) corresponding to the first positioning points (9) at its four corners.