Printing screen for solar cells and photovoltaic module

Abstract

The application is suitable for the technical field of solar cells, and particularly relates to a printing screen plate for a solar cell and a photovoltaic module. The printing screen plate comprises a plate body, at least one main grid printing area arranged on the plate body and extending along a first direction, and a plurality of pad printing areas arranged in the main grid printing area and spaced along the first direction. The plurality of pad printing areas comprise end pad printing areas close to the end of the main grid printing area and intermediate pad printing areas between the end pad printing areas. A plurality of screen holes are arranged in the pad printing areas, and the aperture of at least one screen hole of the end pad printing area is larger than the aperture of at least one screen hole of the intermediate pad printing area. Through the above arrangement, the PAD points close to the end are higher and fuller than the PAD points at the intermediate part, so as to avoid over-welding of the PAD points close to the end and ensure the welding quality and product quality.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, and particularly relates to a printing screen for solar cells and a photovoltaic module. Background Technology

[0002] A solar cell is a photoelectric semiconductor wafer that generates electricity directly using sunlight. As long as it is exposed to light of a certain intensity, it can instantly output voltage and generate current when there is a circuit.

[0003] Solar cells have main grids and fine grids. The main function of the fine grids is to collect current, transferring electrons generated on the silicon wafer surface to the main grids. Multiple pads (pads) are spaced apart along the length of the main grids. The main grids and pads are created using screen printing paste. These pads are then soldered to solder ribbons to conduct the main grid current through the ribbons. However, the pads created using existing screen printing techniques are all the same height. During soldering, the soldering temperature on the sides of the cell is higher than that in the center, which can easily cause over-soldering of the pads on the sides, affecting the soldering quality. Utility Model Content This application provides a printing screen for solar cells, aiming to solve the problem that existing screen printing produces PAD dots with the same height, which can easily lead to over-soldering of PAD dots on both sides.

[0004] This application embodiment is implemented as follows: a printing screen for a solar cell is provided, comprising: plate body; At least one main grid printing area is disposed on the board, the at least one main grid printing area extending along a first direction; and A plurality of pad printing areas are arranged sequentially at intervals within the main grid printing area and along the first direction; The pad printing areas include end pad printing areas near the end of the main gate printing area, and intermediate pad printing areas located between the end pad printing areas; The pad printing area has several mesh holes, and the diameter of at least one mesh hole in the end pad printing area is larger than the diameter of at least one mesh hole in the middle pad printing area.

[0005] Furthermore, the average mesh aperture of the end pad printing area is larger than the average mesh aperture of a portion of the intermediate pad printing area.

[0006] Furthermore, the average mesh aperture of the end pad printing area is greater than the average mesh aperture of each intermediate pad printing area.

[0007] Furthermore, the aperture ratio of the mesh in at least one end pad printing area is greater than the aperture ratio of the mesh in at least one middle pad printing area.

[0008] Furthermore, the aperture ratio of the mesh in all end pad printing areas is greater than that in all middle pad printing areas.

[0009] Furthermore, the aperture ratio of the end pad printing area is 40% to 70%, and the aperture ratio of the middle pad printing area is 30% to 60%.

[0010] Furthermore, among all the pad printing areas distributed in a row in the first direction, the number of end pad printing areas is at least 2.

[0011] Furthermore, the line diameter of the solder pad printing area is 10 micrometers to 25 micrometers.

[0012] Furthermore, the shape of the solder pad printing area includes at least one of the following: circular, elliptical, prismatic, polygonal, or irregular shape.

[0013] Furthermore, the size of the solder pad printing area is 0.5 mm to 2 mm.

[0014] Secondly, this application also provides a photovoltaic module including PAD dots printed using a screen printing plate of a solar cell as described above.

[0015] The beneficial effects of this application are as follows: The solar cell printing screen provided by this application includes a plate; at least one main grid printing area disposed on the plate, the at least one main grid printing area extending along a first direction; and a plurality of pad printing areas disposed within the main grid printing area and spaced apart sequentially along the first direction; the plurality of pad printing areas includes end pad printing areas near the end of the main grid printing area, and intermediate pad printing areas located between the end pad printing areas; the pad printing areas are provided with a plurality of mesh holes, and the aperture of at least one mesh hole in the end pad printing area is larger than the aperture of at least one mesh hole in the intermediate pad printing area. Through the above arrangement, in the PAD points made using the printing screen, the PAD points near the ends are higher and fuller than the PAD points in the middle, thereby avoiding over-soldering of the PAD points near the ends and ensuring welding quality and product quality. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of one embodiment of the printing screen for the solar cell provided in this application; Figure 2 This is a schematic diagram of the mesh structure of an embodiment of the printing screen for a solar cell provided in this application; Figure 3 This is a schematic diagram of an embodiment of the printing screen for a solar cell provided in this application, with a mesh size of 40 mm. Figure 4 This is a schematic diagram of an embodiment of the printing screen for a solar cell provided in this application, with a mesh size of 32mm. Figure 5 This is a schematic diagram of the structure of a single mesh size of an embodiment of the printing screen for a solar cell provided in this application; Figure 6 This is a schematic diagram showing the relationship between the mesh count, wire diameter, and mesh opening of an embodiment of the printing screen for a solar cell provided in this application.

[0017] Explanation of reference numerals in the attached figures: 100 - Board body, 200 - Main grid printing area, 300 - Pad printing area, 310 - End pad printing area, 320 - Middle pad printing area, 330 - Mesh. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this application and are not intended to limit this application.

[0019] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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, and therefore should not be construed as a limitation of this application.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0021] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0022] In this application, unless otherwise expressly specified and limited, "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. Furthermore, "above," "over," and "on top" of 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. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference values ​​and / or reference letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0024] The solar cell printing screen provided in this application includes a plate; at least one main grid printing area disposed on the plate, the at least one main grid printing area extending along a first direction; and a plurality of pad printing areas disposed within the main grid printing area and spaced apart sequentially along the first direction; the plurality of pad printing areas includes end pad printing areas near the end of the main grid printing area, and intermediate pad printing areas located between the end pad printing areas; the pad printing areas are provided with a plurality of mesh holes, and the aperture of at least one mesh hole in the end pad printing area is larger than the aperture of at least one mesh hole in the intermediate pad printing area. With the above arrangement, among the PAD dots produced using the printing screen, the PAD dots near the ends are higher and fuller than the PAD dots in the middle, thereby avoiding over-soldering of the PAD dots near the ends and ensuring welding quality and product quality.

[0025] like Figures 1 to 6 As shown in the figure, this application provides a photovoltaic module, including: Plate 100; At least one main grid printing area 200 is disposed on the plate 100, and the at least one main grid printing area 200 extends along a first direction; and A plurality of pad printing areas 300 are provided within the main grid printing area 200 and are arranged at intervals along the first direction; The plurality of pad printing areas 300 include end pad printing areas 310 near the end of the main gate printing area 200, and intermediate pad printing areas 320 located between the end pad printing areas 310. The pad printing area 300 is provided with a plurality of mesh holes 330, and the aperture of at least one mesh hole 330 in the end pad printing area 310 is larger than the aperture of at least one mesh hole 330 in the middle pad printing area 320.

[0026] In practice, the printing screen for solar cells is usually made of stainless steel mesh, which is a key tool for accurately printing solder paste onto the cells. The surface of the printing screen for solar cells is formed into a precise array of openings by laser cutting, and the size and position of the openings strictly correspond to the required printing area design.

[0027] Plate 100 is the stainless steel sheet mentioned above. Of course, in some other embodiments, plate 100 may also be made of other materials, such as iron, copper, aluminum or their alloys, without limitation.

[0028] The board 100 is provided with a main grid printing area 200 and a pad printing area 300. The main grid printing area 200 is used to print the main grid on the solar cell, and the pad printing area 300 is used to print PAD dots on the solar cell.

[0029] The main grid is a metal line on the surface of a solar cell. Its main function is to collect the current transmitted through the fine grid lines and transmit it to the external circuitry of the cell. Optionally, the number of busbars is typically determined by the cell area, current collection efficiency, and production cost. Generally, the number of busbars is two (dual busbars), three (triple busbars), or more than three, with no fixed limit. In implementation, the dual busbar design has mature technology and lower cost, but the current collection path is longer and the resistance is higher. The triple busbar design, by increasing the number of busbars, shortens the current transmission path, thereby improving conversion efficiency and power output.

[0030] As one possible implementation, the width, height, and shape of the main grid affect battery performance. A wider main grid has lower resistance but reduces the light-receiving area; three-dimensional grid lines (such as triangles) can reduce light-blocking losses and improve photoelectric conversion efficiency. The shape and size of the printed main grid can be controlled by designing the shape and size of the main grid printing area 200.

[0031] It should be noted that the shape and size of the main grid refers to the shape and size of the contact surface between the main grid and the surface of the solar cell. For example, the shape of the main grid can be a long rectangular shape, and the size of the main grid includes the length and width of the main grid. For example, when the shape of the main grid is a long rectangular shape, the length and width of the main grid are the length and width of the long rectangular shape.

[0032] PAD points are metallized areas on the surface of solar cells used for electrical connections. Their main function is to enable current transmission and electrical conduction between the cells of a photovoltaic module.

[0033] In implementation, PADs (Plug-in Disk Adhesives) are used to connect solar cells in series or parallel via conductive adhesive or solder strips, forming a critical path for current transmission in photovoltaic systems. In shingled modules, optimizing the PAD structure (such as a sawtooth design) can improve the utilization rate of conductive adhesive, reduce contact resistance, and thus increase module power.

[0034] In the process of printing solder paste, the printing screen of the solar cell plays a role in precise positioning, and the position of the metal can be precisely controlled by the printing screen of the solar cell.

[0035] Both the main grid printing area 200 and the pad printing area 300 are provided with multiple meshes 330. These meshes 330 are used to allow metal paste (such as silver powder or aluminum) to pass through to the designated coating position, forming a high-quality metal area, optimizing the charge transmission path, reducing power loss, and improving the overall power generation performance.

[0036] The main grid printing area 200 extends along the first direction, which is represented by line segment L for ease of understanding.

[0037] In the first direction, a plurality of pad printing areas 300 are arranged sequentially at intervals, and the aperture of at least one mesh 330 in the end pad printing area 310 is larger than the aperture of at least one mesh 330 in the middle pad printing area 320. For a single mesh 300, the larger the aperture of the mesh 300, the more metal paste can pass through, resulting in a higher and fuller PAD point. In other words, when printing PAD points, the height of PAD points near the ends can be made higher than the height of PAD points located in the middle, thereby avoiding over-soldering of PAD points near the ends and ensuring soldering quality and product quality.

[0038] In some embodiments, the average mesh aperture of the end pad printing area 310 is larger than the average mesh aperture of a portion of the intermediate pad printing area 320. Since the pad printing area 300 has a plurality of mesh apertures 330, that is, the end pad printing area 310 has multiple mesh apertures 330, and similarly, the intermediate pad printing area 320 also has multiple mesh apertures 330. For the same pad printing area 300, the plurality of mesh apertures 330 may have the same aperture size, or some or all of the mesh apertures 330 may have different aperture sizes. The average mesh aperture refers to the average aperture of several mesh holes 330 within the same pad printing area 300. By designing the average mesh aperture of the end pad printing area 310 to be larger than the average mesh aperture of some of the intermediate pad printing areas 320, and even further, designing the average mesh aperture of the end pad printing area 310 to be larger than the average mesh aperture of each intermediate pad printing area, it can be ensured that the PAD points obtained from the end pad printing area 310 are higher and fuller than the PAD points obtained from the intermediate pad printing area 320.

[0039] In some embodiments, the aperture ratio of the mesh 330 of at least one end pad printing area 310 is greater than the aperture ratio of the mesh 330 of all intermediate pad printing areas 320.

[0040] In practice, the aperture ratio refers to the ratio of the area of ​​the mesh 330 to the area formed by the mesh 330 and the wire diameter (wire diameter). For ease of understanding, let's take a square mesh 330 as an example, where the mesh opening (aperture) is OP and the wire diameter is D. Figure 5 As shown. The formula for calculating the opening ratio (OPA%) is: For example, when there is one or more end pad printing areas 310, the aperture ratio of the mesh 330 of the end pad printing area 310 closest to the end can be designed to be larger than the aperture ratio of the mesh 330 of all intermediate pad printing areas 320, or the aperture ratio of the mesh 330 of the second end pad printing area 310 closest to the end can be designed to be larger than the aperture ratio of the mesh 330 of all intermediate pad printing areas 320, or the aperture ratio of the mesh 330 of the end pad printing area 310 closest to the end and the second end pad printing area 310 closest to the end can be designed to be larger than the aperture ratio of the mesh 330 of all intermediate pad printing areas 320. Of course, the aperture ratio of the mesh 330 of all end pad printing areas 310 can also be greater than the aperture ratio of the mesh 330 of all intermediate pad printing areas 320, which will not be elaborated further.

[0041] Optionally, the aperture ratio of the end pad printing area 310 is 40% to 70%. For example, the aperture ratio of the end pad printing area 310 can be designed to be any value among 41%, 42%, 43%, 44%, 45%, 50%, 55%, 60%, 65%, 68%, or 40% to 70%, without specific limitation.

[0042] In practice, the aperture ratio can be converted into the aperture of mesh 330, which is represented by D1. Figure 2 As shown. For example, the aperture of the mesh 330 located in the end pad printing area 310 is designed to be 30 micrometers to 70 micrometers. For example, the aperture of the mesh 330 in the end pad printing area 310 can be any value from 31 micrometers, 32 micrometers, 35 micrometers, 40 micrometers, 45 micrometers, 50 micrometers, 55 micrometers, 60 micrometers, 65 micrometers or 30 micrometers to 70 micrometers, without specific limitation.

[0043] Optionally, the aperture ratio of the intermediate pad printing area 320 is 30% to 60%. For example, the aperture ratio of the intermediate pad printing area 320 can be designed to be any value among 31%, 32%, 33%, 34%, 35%, 40%, 45%, 50%, 55%, 58% or 30% to 60%, without specific limitation.

[0044] In implementation, the aperture of the mesh 330 of the intermediate pad printing area 320 is 20 micrometers to 40 micrometers. For example, the aperture of the mesh 330 of the intermediate pad printing area 320 can be designed to be any value among 21 micrometers, 22 micrometers, 25 micrometers, 26 micrometers, 28 micrometers, 30 micrometers, 32 micrometers, 35 micrometers, 38 micrometers or 20 micrometers to 40 micrometers, without specific limitation.

[0045] For ease of understanding, the relationship between the mesh count, wire diameter, and mesh opening of the 300-grid solder pad printing area is as follows: Figure 6 As shown.

[0046] With the above settings, when printing PAD dots, the height of PAD dots near the ends can be made higher than the height of PAD dots in the middle, thereby avoiding over-soldering of PAD dots near the ends and ensuring welding quality and product quality.

[0047] In some embodiments, among all the pad printing areas 300 distributed in a row in a first direction, the mesh size of at least one end pad printing area 310 is larger than the mesh size of at least one middle pad printing area 320.

[0048] In practice, if the solar cell has multiple main grids, the solder pad printing area 300 will also correspond one-to-one with the multiple main grids and be distributed in multiple columns.

[0049] For example, taking the first direction as the vertical direction, that is, the main gate extends in the vertical direction, and multiple main gates are distributed at intervals in the horizontal direction, and several pad printing areas 300 are arranged in several columns, with multiple pad printing areas 300 in each column being distributed vertically at intervals.

[0050] When there are three columns of solder pad printing areas 300, and each column has six solder pad printing areas 300, the first solder pad printing area 300 is located at the top, the second solder pad printing area 300 is located below the first solder pad printing area 300, and so on, with the sixth solder pad printing area 300 located at the bottom. At this time, the first solder pad printing area 300 and the sixth solder pad printing area 300 are the end solder pad printing areas 310, and the second solder pad printing area 300, the third solder pad printing area 300, the fourth solder pad printing area 300, and the fifth solder pad printing area 300 are the middle solder pad printing areas 320.

[0051] In the first and third columns, the mesh size of the first pad printing area 300 is larger than that of the second, third, fourth, and fifth pad printing areas 300. In the second column, the mesh size of the first pad printing area 300 can be designed to be larger than that of the second, third, fourth, and fifth pad printing areas 300, or it can be designed to be the same as that of the second, third, fourth, and fifth pad printing areas 300.

[0052] In some possible embodiments, taking four columns of solder pad printing areas 300 as an example, with eight solder pad printing areas 300 in each column, the first solder pad printing area 300 is located at the top, the second solder pad printing area 300 is located below the first solder pad printing area 300, and so on, with the eighth solder pad printing area 300 located at the bottom. In this case, the first solder pad printing area 300 and the eighth solder pad printing area 300 are the end solder pad printing areas 310, and the second solder pad printing area 300, the third solder pad printing area 300, the fourth solder pad printing area 300, the fifth solder pad printing area 300, the sixth solder pad printing area 300, and the seventh solder pad printing area 300 are the middle solder pad printing areas 320.

[0053] In the first, second, and third columns, the mesh size of the first and eighth pad printing areas 300 is larger than that of the second, third, fourth, fifth, sixth, and seventh pad printing areas 300. However, in the fourth column, the mesh size of the eighth pad printing area 300 can be designed to be larger than that of the second, third, fourth, fifth, sixth, and seventh pad printing areas 300.

[0054] Optionally, among all pad printing areas 300 in the same column, the mesh of the end pad printing area 310 can be designed to be larger than the mesh of at least one intermediate pad printing area 320.

[0055] For example, when there are two columns of solder pad printing areas 300, and each column has five solder pad printing areas 300, the first solder pad printing area 300 is located at the top, the second solder pad printing area 300 is located below the first solder pad printing area 300, and so on, with the fifth solder pad printing area 300 located at the bottom. In this case, the first solder pad printing area 300 and the fifth solder pad printing area 300 are the end solder pad printing areas 310, and the second solder pad printing area 300, the third solder pad printing area 300, and the fourth solder pad printing area 300 are the middle solder pad printing areas 320.

[0056] In the first column, the mesh size of the first pad printing area 300 is the same as that of the second pad printing area 300, and the mesh size of the first pad printing area 300 is larger than that of the third and fourth pad printing areas 300.

[0057] In the second column, the first, second, fourth, and fifth pad printing areas 300 have the same mesh size, and the mesh size of the first pad printing area 300 is larger than that of the third pad printing area 300.

[0058] Similarly, if there are three columns of solder pad printing areas 300, and each column has seven solder pad printing areas 300, the first solder pad printing area 300 is located at the top, the second solder pad printing area 300 is located below the first solder pad printing area 300, and so on, with the seventh solder pad printing area 300 located at the bottom. In this case, the first and seventh solder pad printing areas 300 are the end solder pad printing areas 310, and the second, third, fourth, fifth, and sixth solder pad printing areas 300 are all middle solder pad printing areas 320.

[0059] In the first column, the mesh size of the first and seventh pad printing areas 300 is larger than that of the second, third, fourth, fifth, and sixth pad printing areas 300.

[0060] In the second column, the mesh size of the first pad printing area 300 and the seventh pad printing area 300 is only larger than that of the third pad printing area 300.

[0061] In the third column, the mesh sizes of the first, second, sixth, and seventh pad printing areas 300 are all larger than those of the third, fourth, and fifth pad printing areas 300.

[0062] Optionally, among all the pad printing areas 300 distributed in a row in the first direction, the number of end pad printing areas 310 is at least 2.

[0063] For example, when there are two columns of pad printing areas 300, and each column has ten pad printing areas 300, the first pad printing area 300 is located at the top, the second pad printing area 300 is located below the first pad printing area 300, and so on, with the tenth pad printing area 300 located at the bottom. At this time, the first pad printing area 300, the second pad printing area 300, the ninth pad printing area 300, and the tenth pad printing area 300 are all end pad printing areas 310, and the third to eighth pad printing areas 300 are all intermediate pad printing areas 320. Alternatively, the first pad printing area 300, the second pad printing area 300, the third pad printing area 300, the eighth pad printing area 300, the ninth pad printing area 300, and the tenth pad printing area 300 are all end pad printing areas 310, and the fourth to seventh pad printing areas 300 are all intermediate pad printing areas 320.

[0064] In all the pad printing areas 300 distributed in a row in the first direction, the mesh size of at least two end pad printing areas 310 is larger than the mesh size of any one of the middle pad printing areas 320.

[0065] Taking the above two columns, each with ten pad printing areas 300 as an example, in the first column, the mesh size of the first pad printing area 300, the second pad printing area 300, the ninth pad printing area 300, and the tenth pad printing area 300 is larger than the mesh size of the third to eighth pad printing areas 300.

[0066] As one possible implementation, in the first column, the mesh size of the first pad printing area 300, the second pad printing area 300, the third pad printing area 300, the fourth pad printing area 300, the ninth pad printing area 300, and the tenth pad printing area 300 can also be designed to be larger than the mesh size of the fifth to eighth pad printing areas 300.

[0067] Alternatively, also in the first column, the mesh size of the first pad printing area 300, the second pad printing area 300, the ninth pad printing area 300, and the tenth pad printing area 300 can be designed to be larger than the mesh size of the sixth pad printing area 300 and the seventh pad printing area 300.

[0068] The solar cell printing stencil provided in this application includes a plate 100; at least one main grid printing area 200 disposed on the plate 100, the at least one main grid printing area 200 extending along a first direction; and a plurality of pad printing areas 300 disposed on the plate 100 and spaced apart sequentially along the first direction; the plurality of pad printing areas 300 includes end pad printing areas 310 near the end, and intermediate pad printing areas 320 located between the end pad printing areas 310; the pad printing areas 300 are provided with a plurality of mesh openings 330, the mesh openings of the end pad printing areas 310 being larger than the mesh openings of the intermediate pad printing areas 320. Through the above arrangement, since the mesh openings 330 of the end pad printing areas 310 are larger than the mesh openings 330 of the intermediate pad printing areas 320, the PAD points made using the printing stencil are higher and fuller near the end than the PAD points in the middle, thereby avoiding over-soldering of the PAD points near the end and ensuring welding quality and product quality.

[0069] In some possible embodiments, the wire diameter of the pad printing area 300 is represented by D2, such as... Figure 2 As shown. D2 is 10 micrometers to 25 micrometers. For example, the line diameter of the pad printing area 300 can be designed to be any value from 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 18 micrometers, 20 micrometers, 22 micrometers, 24 micrometers or 10 micrometers to 25 micrometers, without specific limitation.

[0070] For example, taking the aperture of the mesh 330 in the end pad printing area 310 as 40mm as an example, Figure 3 As shown. The aperture of the mesh 330 in the middle pad printing area 320 is less than 40mm. For example, the aperture of the mesh 330 in the middle pad printing area 320 can be designed to be 32mm. The line diameter of both the 40mm and 32mm aperture pad printing areas is 15mm. Figure 4 As shown.

[0071] In some other embodiments, the shape of the mesh 330 of the pad printing area 300 includes at least one of the following: circular, elliptical, prismatic, polygonal, or irregular shapes, without limitation. The aperture and wire diameter of the mesh 330 of the pad printing area 300 can be determined according to the shape of the mesh 330.

[0072] For example, taking the shape of the mesh 330 of the pad printing area 300 as a circle, the diameter of the circle is the aperture of the mesh 330 of the pad printing area 300, and the shortest distance between two adjacent circles is the wire diameter.

[0073] Optionally, when the shape of the mesh 330 of the pad printing area 300 is elliptical, the major diameter and minor diameter of the ellipse are the length and width of the mesh 330 of the pad printing area 300, respectively, and the shortest distance between two adjacent ellipses is the wire diameter.

[0074] Optionally, when the mesh 330 of the pad printing area 300 is hexagonal, the distance between two opposite sides of the hexagon is the length and width of the mesh 330 of the pad printing area 300, and the distance between two adjacent hexagons is the wire diameter.

[0075] Optionally, when the shape of the mesh 330 of the pad printing area 300 is octagonal, the distance between two opposite sides of the octagon is the length and width of the mesh 330 of the pad printing area 300, and the distance between two adjacent octagons is the wire diameter.

[0076] In some possible embodiments, the shape of the pad printing area 300 includes at least one of the following: circular, elliptical, prismatic, polygonal, or irregular shape, without limitation.

[0077] The shape of the pad printing area 300 can be regarded as the projection shape of the PAD point on the printing surface. For example, when the PAD is electro-printed on the first surface of the battery cell, the projection shape of the PAD point on the first surface includes at least one of the following: circle, ellipse, rhombus, polygon or irregular shape, without limitation.

[0078] Optionally, the size of the pad printing area 300 is from 0.5 mm to 2 mm, for example, the size of the pad printing area 300 is any value from 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm or 0.5 mm to 2 mm, without limitation.

[0079] Optionally, the dimensions of the pad printing area 300 include the length and width of the pad printing area 300.

[0080] For example, when the shape of the pad printing area 300 is circular, the diameter of the circle is the length and width of the pad printing area 300.

[0081] In some possible embodiments, taking the shape of the pad printing area 300 as an example, the major diameter of the ellipse is the length of the pad printing area 300, and the minor diameter of the ellipse is the width of the pad printing area 300.

[0082] In some possible embodiments, taking the shape of the pad printing area 300 as a rectangle as an example, the length of the rectangle is the length of the pad printing area 300, and the width of the rectangle is the width of the pad printing area 300.

[0083] Optionally, taking the shape of the pad printing area 300 as a regular hexagon as an example, the side length of the regular hexagon is the length or width of the pad printing area 300.

[0084] Optionally, taking the shape of the pad printing area 300 as a regular octagon as an example, the side length of the regular octagon is the length or width of the pad printing area 300.

[0085] In some possible embodiments, taking a regular hexagonal shape for the pad printing area 300 as an example, the distance between two opposite sides of the regular hexagon can be considered as the length and width of the pad printing area 300. Similarly, taking a regular octagonal shape for the pad printing area 300 as an example, the distance between two opposite sides of the regular octagon can be considered as the length and width of the pad printing area 300, which will not be elaborated further.

[0086] Optionally, the thickness of the plate 100 is 10 micrometers to 20 micrometers. For example, the thickness of the plate 100 can be designed to be any value among 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 17 micrometers, 18 micrometers, 19 micrometers or 10 micrometers to 20 micrometers, without specific limitation.

[0087] In some embodiments, this application also provides a photovoltaic module including PAD dots printed using a screen printing plate of a solar cell as described above.

[0088] Photovoltaic modules are the core components of solar power generation systems. They convert light energy into electrical energy by connecting individual solar cells in series, based on the photovoltaic effect. Modules consist of tempered glass, an EVA sealing layer, a TPT backsheet, and an aluminum alloy frame. The solar cells are encapsulated through processes such as welding and lamination.

[0089] In practice, a solar cell is a thin photovoltaic semiconductor wafer that generates electricity directly using sunlight. The production process of a solar cell includes silicon wafer inspection, surface texturing and acid washing, diffusion junction formation, dephosphosilicate glass, plasma etching and acid washing, anti-reflective coating deposition, screen printing, and rapid sintering.

[0090] Positive and negative electrodes need to be made on the surface of the solar cell. There are many methods to manufacture electrodes, but screen printing is the most common production process for solar cell electrodes.

[0091] Screen printing is a process of printing a predetermined pattern onto a substrate using an impression method. The ink passes through the mesh openings 330 of the screen's pattern area. A squeegee applies pressure to the ink area of ​​the screen while moving towards the other end. During this movement, the ink is forced from the mesh openings 330 onto the substrate by the squeegee. Due to the adhesive properties of the ink, the print adheres within a certain range. Throughout the printing process, the squeegee maintains linear contact with both the screen and the substrate, and the contact line moves with the squeegee, thus completing the printing process.

[0092] Electrodes manufactured by screen printing include a fine grid and a main grid, which are connected. The fine grid is used to collect current to transfer electrons generated on the silicon wafer surface to the main grid. The main grid has several PAD points, which are used to be soldered to the solder ribbon to achieve current conduction.

[0093] In the extension direction of the main grid, several PAD points are distributed at intervals. Since the PAD points are made using the printing screen described above, the height of the PAD points near the ends is higher than the height of the PAD points located in the middle.

[0094] Those skilled in the art will understand that, for the sake of convenience and brevity, the structure and implementation principle of the photovoltaic module described above can be referred to the corresponding structure and implementation principle in the foregoing embodiments, and will not be repeated here.

[0095] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A printing screen for solar cells, characterized in that, include: plate body; At least one main grid printing area is provided on the plate body, and at least one main grid printing area extends along a first direction; as well as A plurality of pad printing areas are provided within the main gate printing area and are arranged at intervals along the first direction; The plurality of said pad printing areas include end pad printing areas near the end of the main gate printing area, and intermediate pad printing areas located between the end pad printing areas; The pad printing area is provided with a plurality of mesh holes, and the aperture of at least one mesh hole in the end pad printing area is larger than the aperture of at least one mesh hole in the middle pad printing area.

2. The printing screen for a solar cell as described in claim 1, characterized in that, The average mesh size of the end pad printing area is greater than the average mesh size of a portion of the intermediate pad printing area.

3. The printing screen for a solar cell as described in claim 1, characterized in that, The average mesh size of the end pad printing area is greater than the average mesh size of each of the intermediate pad printing areas.

4. The printing screen for a solar cell as described in claim 1, characterized in that, The aperture ratio of the mesh in at least one of the end pad printing areas is greater than the aperture ratio of the mesh in at least one of the intermediate pad printing areas.

5. The printing screen for a solar cell as described in claim 4, characterized in that, The aperture ratio of the mesh in all the end pad printing areas is greater than that in all the intermediate pad printing areas.

6. The printing screen for a solar cell as described in claim 4, characterized in that, The aperture ratio of the end pad printing area is 40% to 70%, and the aperture ratio of the middle pad printing area is 30% to 60%.

7. The printing screen for a solar cell as described in claim 1, characterized in that, Of all the pad printing areas distributed in a row in the first direction, the number of end pad printing areas is at least two.

8. The printing screen for a solar cell as described in claim 1, characterized in that, The line diameter of the printed pad area is 10 micrometers to 25 micrometers.

9. The printing screen for a solar cell as described in any one of claims 1 to 8, characterized in that, The shape of the solder pad printing area includes at least one of the following: circular, elliptical, prismatic, polygonal, or irregular shape.

10. The printing screen for a solar cell as described in claim 9, characterized in that, The size of the printed pad area is 0.5 mm to 2 mm.

11. A photovoltaic module, characterized in that, Includes PAD dots printed using a printing screen of a solar cell as described in any one of claims 1 to 10.

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