Screen printing plate, manufacturing method and solar cell

Abstract

The invention relates to the technical field of screen printing plates, in particular to a printing screen printing plate, a manufacturing method and a solar cell. The screen printing plate comprises a screen printing plate layer, the screen printing plate layer is provided with a printing groove extending in the first direction, the printing groove penetrates through the screen printing plate layer in the thickness direction of the screen printing plate layer, the printing groove comprises a plurality of first groove sections and second groove sections which are alternately connected in the first direction, and the maximum width of the first groove sections in the second direction is larger than that of the second groove sections in the second direction; the minimum width of the first groove section in the second direction is larger than or equal to the maximum width of the second groove section in the second direction, and every two of the first direction, the second direction and the thickness direction of the screen printing plate layer are perpendicular to each other; the groove depth size of the first groove section in the thickness direction of the screen printing plate layer is smaller than the groove depth size of the second groove section in the thickness direction of the screen printing plate layer. The grid line printed by the printing screen not only integrates the welding performance of the assembly and the low resistance performance of the grid line, but also can reduce the cost.

Description

Technical Field

[0001] This application relates to the field of screen printing technology, and more particularly to a printing screen and its manufacturing method, and a solar cell. Background Technology

[0002] Metallization is a core step in solar cell manufacturing, with the primary goal of forming highly efficient conductive electrode structures (grid lines) on the solar cell surface to achieve low-loss collection and extraction of photocurrent. Solar cell grid lines are printed using a screen printing plate. Typically, the screen has printing grooves that match the grid line pattern, and metal paste is formed within these grooves. With the advancement of cell technology, thinning the grid lines is currently a key focus. Simultaneously, to address the increased line resistance and carrier transport losses caused by narrower grid line widths, the grid line height is usually increased to compensate for line resistance losses. However, this leads to larger paste consumption in the locally widened soldering areas on the grid lines, and also increases the risk of poor soldering during module assembly. Summary of the Invention

[0003] This application discloses a printing screen and its manufacturing method, as well as a solar cell. The grid lines printed by the printing screen have both the welding performance of the module and the low resistance performance of the grid lines, while also reducing costs.

[0004] To achieve the above objectives, in a first aspect, embodiments of this application disclose a printing screen, including a screen layer; The screen layer is provided with a printing groove extending along a first direction. The printing groove penetrates the screen layer along the thickness direction of the screen layer. The printing groove includes a number of first groove segments and second groove segments that are alternately connected along the first direction. The maximum width of the first groove segment along the second direction is greater than the maximum width of the second groove segment along the second direction, and the minimum width of the first groove segment along the second direction is greater than or equal to the maximum width of the second groove segment along the second direction. The first direction, the second direction, and the thickness direction of the screen layer are perpendicular to each other. The groove depth of the first groove segment along the thickness direction of the screen layer is smaller than the groove depth of the second groove segment along the thickness direction of the screen layer.

[0005] As an optional implementation, the screen layer includes a first side and a second side opposite to each other along the thickness direction of the screen layer, the first side being the slurry inlet side; On the second side surface of the screen layer, the area adjacent to the second groove segment is flush with the area adjacent to the first groove segment; In the first side surface of the screen layer, the area adjacent to the periphery of the first groove segment is positioned at a lower height relative to the second side surface than the area adjacent to the periphery of the first groove segment is positioned relative to the second side surface.

[0006] As an optional implementation, the screen printing layer includes a main layer and a thickening layer stacked on the main layer, with the thickening layer located on the first side of the main layer; The first trench is located in the main layer, and the second trench runs through the thickened layer and the main layer.

[0007] As an optional implementation, the printing screen also includes a skeleton structure layer, which is stacked on the main body layer and is located on the same side surface of the main body layer as the thickening layer. The skeleton structure layer is provided with a through ink storage tank, which is connected to the printing tank, and the width of the ink storage tank along the second direction is greater than the width of the printing tank along the second direction. The thickened layer is located inside the ink reservoir.

[0008] As an optional implementation, the thickening layer includes several thickening portions, with each second groove segment having a thickening portion on each of its opposite sides along the second direction.

[0009] As an optional implementation, the printing screen also includes a reinforcing section disposed on the inner sidewall of the first groove section; The reinforcing part is at least partially hollowed out, and the hollowed-out part of the reinforcing part is connected to the printing groove; the surface of the reinforcing part has an arched structure.

[0010] Secondly, this application discloses a method for producing a printing screen, comprising the following steps: A semi-finished screen printing plate is provided, comprising a main body layer. A through groove extending along a first direction is formed on the main body layer. The through groove penetrates the main body layer along its thickness. The through groove includes a plurality of alternating first groove segments and transition groove segments connected along the first direction. The maximum width of the first groove segment along a second direction is greater than the maximum width of the transition groove segment along the second direction, and the minimum width of the first groove segment along the second direction is greater than or equal to the maximum width of the transition groove segment along the second direction. The groove depth of the first groove segment along the thickness direction of the main body layer is equal to the groove depth of the transition groove segment along the thickness direction of the main body layer. The first direction, the second direction, and the thickness direction of the main body layer are perpendicular to each other. A thickening layer is formed on one side of the surface of the main layer in the thickness direction, and thickening layers are provided on both sides of each transition groove segment in the second direction, so that the groove wall of the transition groove segment and the corresponding thickening layer together define the second groove segment. The groove depth of the first groove segment along the thickness direction of the main layer is smaller than the groove depth of the second groove segment along the thickness direction of the main layer.

[0011] As an optional implementation, prior to the step of forming the thickened layer, the following steps are also included: A skeleton structure layer is formed on one side surface of the main layer in the thickness direction. The skeleton structure layer is provided with a through ink storage tank, which is connected to the first tank segment and the transition tank segment. In the step of forming the thickened layer, the thickened layer is located inside the ink reservoir.

[0012] As an optional implementation, the step of forming a thickening layer on one side of the main layer in the thickness direction specifically includes: A mask structure is provided on one side of the main body layer where the skeleton structure layer is located, and the mask structure exposes only the target area of ​​the main body layer; On the surface of the main layer in this thickness direction, the area not covered by the mask structure forms a thickened layer; The target area of ​​the main body layer is the portion of the exposed self-storage ink tank of the main body layer that corresponds to the transition tank section.

[0013] Thirdly, this application discloses a solar cell, comprising: Solar cell preforms; and The collector grid line is disposed on the surface of the solar cell preform and extends along a first direction. The collector grid line includes a plurality of connecting portions and carrier collecting portions alternately connected along the first direction. The maximum width of the connecting portion along the second direction is greater than the maximum width of the carrier collecting portion along the second direction, and the minimum width of the connecting portion along the second direction is greater than or equal to the maximum width of the carrier collecting portion along the second direction. The first direction, the second direction, and the thickness direction of the solar cell preform are perpendicular to each other. In the thickness direction of the solar cell preform, the height of the connector is less than the height of the carrier collection section.

[0014] Compared with related technologies, the beneficial effects of this application are: In this application, a printing groove extending along a first direction is provided in the screen layer. The printing groove penetrates the screen layer along its thickness direction, allowing metal paste to be printed onto the solar cell preform after passing through the printing groove to form grid lines. Here, we will use a current collector grid line as an example. Since the printing groove includes several alternating first and second groove segments connected along the first direction, the maximum width of the first groove segment along the second direction is greater than the maximum width of the second groove segment along the second direction, and the minimum width of the first groove segment along the second direction is greater than or equal to the maximum width of the second groove segment along the second direction. This results in the maximum width of the portion formed by the first groove segment in the printed current collector grid line being greater than the maximum width of the portion formed by the second groove segment, and the minimum width of the portion formed by the first groove segment being greater than or equal to the maximum width of the portion formed by the second groove segment. Correspondingly, in the current collector grid line, the portion formed by the first groove segment is locally wider along the second direction compared to the portion formed by the second groove segment.

[0015] Because the groove depth of the first groove segment along the thickness direction of the screen layer is smaller than that of the second groove segment, the height of the portion formed by the first groove segment in the printed collector grid is smaller than the height of the portion formed by the second groove segment. Consequently, the height of the locally widened portion in the collector grid is set lower than that of other portions. When it is necessary to increase the height of the collector grid to compensate for line resistance loss, this can be achieved by setting the height of the portion formed by the second groove segment higher and the height of the portion formed by the first groove segment lower. Compared with related technologies where the entire collector grid height is set high, this application, by setting the height of the wider portion, i.e., the portion formed by the first groove segment, lower, can save paste to a certain extent while ensuring the welding performance of the component. It balances the welding performance of the component and the low resistance performance of the collector grid, and also reduces costs. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of the printing screen disclosed in this application; Figure 2 for Figure 1 A magnified view of a portion at point A; Figure 3 This is a schematic diagram of the printing screen disclosed in this application after being cut along the printing groove; Figure 4 This is a cross-sectional view of the printing screen disclosed in this application, obtained by cutting the first groove segment. Figure 5 This is a flowchart illustrating the method for producing the printing screen disclosed in this application; Figure 6 This is a schematic diagram of the process of forming a first conductive material layer and a first mask layer on a substrate in the method for manufacturing a printing screen disclosed in this application. Figure 7 for Figure 6 Top view; Figure 8 This is a schematic diagram of the formation of the second conductive material layer in the method for manufacturing the printing screen disclosed in this application; Figure 9 for Figure 8 Top view; Figure 10 This is a schematic diagram of the formation of the third conductive material layer and the second mask layer in the method for manufacturing the printing screen disclosed in this application; Figure 11 for Figure 10 Top view; Figure 12 This is a schematic diagram illustrating the formation of the reinforcing section in the method for manufacturing the printing screen disclosed in this application; Figure 13 for Figure 12 Top view; Figure 14 This is a schematic diagram illustrating the formation of the main layer in the method for producing the printing screen disclosed in this application; Figure 15 for Figure 14 Top view; Figure 16 This is a schematic diagram of the method for manufacturing a printing screen disclosed in this application, showing the formation of a skeleton structure layer. Figure 17 for Figure 16 Top view; Figure 18 This is a schematic diagram of the mask structure formed in the method for manufacturing the printing screen disclosed in this application; Figure 19 This is a schematic diagram illustrating the formation of a thickened layer in the method for manufacturing a printing screen disclosed in this application; Figure 20 for Figure 19 Top view; Figure 21 This is a schematic diagram of the printing screen formed in the method for making the printing screen disclosed in this application; Figure 22 for Figure 21 Top view; Figure 23 This is a schematic diagram of the structure of the solar cell disclosed in this application.

[0018] Explanation of reference numerals in the attached figures: 100. Printing screen printing plate; 10. Screen layer; 20. Printing groove; 21. First groove section; 22. Second groove section; 201. Through-slot; 23. Transition slot section; 30. Main body layer; 40. Thickened layer; 41. Thickened section; 50. Skeleton structure layer; 51. Ink reservoir; 60. Reinforcing section; 601. Arched structure; 61. Strip structure; 70. Collector grid line; 71. Connecting part; 711. First connecting part; 712. Second connecting part; 72. Charge carrier collection part; 80. Busbar; F, First direction; S, Second direction; T, Thickness direction of the screen printing layer; T1, First side; T2, Second side; T3, Thickness direction of the main layer; M, Target area; B1, First surface; B2, Second surface; Z1, First region; Z2, Second region; 200. Solar cell; 2001. Screen printing plate semi-finished product; 2002. Solar cell pre-product; 210. Substrate; 221. First conductive material layer; 222. Second conductive material layer; 223. Third conductive material layer; 231. First mask layer; 232. Second mask layer; 240. Mask structure. Detailed Implementation

[0019] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0020] In this application, the terms "upper," "inner," "outer," "front," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0021] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0022] Furthermore, the terms "set up," "equipped with," "connected," and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0023] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0024] Metallization is a core step in solar cell manufacturing. Its core objective is to form highly efficient conductive electrode structures (grid lines) on the surface of the solar cell, enabling low-loss collection and extraction of photocurrent. The grid lines of a solar cell can be printed using a screen printing plate. Specifically, metal paste is printed onto the solar cell preform after passing through printing grooves on the screen. The pattern of these printing grooves matches the pattern of the grid lines, thus forming a predetermined patterned shape from the printed metal paste. The grid lines are then obtained after subsequent sintering of the metal paste.

[0025] With the iteration of battery technology, metallization processes have been continuously innovated to adapt to high-efficiency battery structures. Among these innovations, the reduction of grid line width is one of the core directions of current technological iteration, aiming to reduce the consumption of metal paste and increase the light-receiving area by narrowing the grid line width, thereby achieving both efficiency improvement and cost reduction. Taking a fully open screen printing plate as an example, the relevant technology's fully open screen printing plate includes a screen layer with printing grooves. Metal paste is printed onto the solar cell preform after passing through the printing grooves to obtain the grid lines. Since the groove depth is consistent throughout the printing groove's extension direction, the height of the printed grid lines is basically consistent throughout its extension direction. With the development of grid line thinning, the narrowing of the grid line width leads to a significant increase in line resistance, greatly increasing carrier transport losses and limiting the improvement of battery efficiency. To address this, most related technologies use increasing the grid line height to compensate for line resistance losses. However, the grid lines usually have locally widened welding areas to facilitate welding. When the grid line height increases, these locally widened welding areas consume more paste, and there is also a risk of poor soldering during module welding.

[0026] Based on the above analysis, this application provides a printing screen with printing grooves that can be used to print grid lines, such as current collector grid lines. By setting different groove depths for the first and second groove segments, the wider first groove segment has a smaller groove depth, while the narrower second groove segment has a larger groove depth. Correspondingly, in the printed current collector grid lines, the portion formed by the first groove segment is wider but shorter, thus saving paste to some extent while ensuring the welding performance of the component. The portion formed by the second groove segment is narrower but taller, which meets the requirement of reducing the line resistance of the current collector grid lines. In other words, the grid lines printed by the printing screen of this application take into account both the welding performance of the component and the low resistance performance of the current collector grid lines, while also reducing costs.

[0027] The technical solution of the present invention will now be described in conjunction with the embodiments and accompanying drawings.

[0028] In a first aspect, embodiments of this application disclose a printing screen 100. Please refer to... Figure 1 , Figure 2 andFigure 3 , Figure 1 This is a schematic diagram of the structure of the printing screen 100 disclosed in this application. Figure 2 for Figure 1 A magnified view of a portion at point A. Figure 3 This is a schematic diagram showing the printing screen 100 disclosed in this application after being cut along the printing groove 20. Figure 1 In the diagram, for ease of observation, the illustration after omitting the thickened layer 40 is shown in the figure below. Figure 1 The upper part of the image. Figure 3 In order to facilitate the differentiation of the structure of each part in the printing screen 100, different types of shading lines are added to each part of the structure. In addition, in this application, for ease of explanation, a first direction F and a second direction S that are perpendicular to each other are defined, and the first direction F and the second direction S are both perpendicular to the thickness direction T of the screen layer 10.

[0029] This application discloses a printing screen 100, including a screen layer 10. The screen layer 10 has printing grooves 20 extending along a first direction F. The printing grooves 20 penetrate the screen layer 10 along its thickness direction T. The printing grooves 20 include a plurality of alternating first groove segments 21 and second groove segments 22 connected along the first direction F. The maximum width of the first groove segment 21 along the second direction S is greater than the maximum width of the second groove segment 22 along the second direction S, and the minimum width of the first groove segment 21 along the second direction S is greater than or equal to the maximum width of the second groove segment 22 along the second direction S. The groove depth dimension D1 of the first groove segment 21 along the thickness direction T of the screen layer is smaller than the groove depth dimension D2 of the second groove segment 22 along the thickness direction T of the screen layer.

[0030] In this application, a printing groove 20 extending along the first direction F is provided in the screen layer 10. The printing groove 20 penetrates the screen layer 10 along the thickness direction T. Therefore, the metal paste can be printed onto the solar cell preform after passing through the printing groove 20 to form grid lines. Here, the grid line is taken as a collector grid line 70 as an example. Since the printing groove 20 includes a plurality of first groove segments 21 and second groove segments 22 alternately connected along the first direction F, the maximum width of the first groove segment 21 along the second direction S is greater than the maximum width of the second groove segment 22 along the second direction S, and the minimum width of the first groove segment 21 along the second direction S is greater than or equal to the maximum width of the second groove segment 22 along the second direction S, the maximum width of the portion formed by the first groove segment 21 in the printed collector grid line 70 is greater than the maximum width of the portion formed by the second groove segment 22, and the minimum width of the portion formed by the first groove segment 21 in the printed collector grid line 70 is greater than or equal to the maximum width of the portion formed by the second groove segment 22. Corresponding to the collector grid line 70, the portion formed by the first slot segment 21 is locally widened along the second direction S relative to the portion formed by the second slot segment 22.

[0031] Because the groove depth of the first groove segment 21 along the thickness direction T of the screen layer is smaller than that of the second groove segment 22 along the thickness direction T of the screen layer, the height of the portion of the printed collector grid line 70 formed by the first groove segment 21 is smaller than the height of the portion formed by the second groove segment 22. Consequently, the height of the locally widened portion of the collector grid line 70 is set lower than that of other portions. When it is necessary to increase the height of the collector grid line 70 to compensate for line resistance loss, this can be achieved by setting the height of the portion formed by the second groove segment 22 higher and the height of the portion formed by the first groove segment 21 lower. Compared with related technologies where the entire height of the collector grid line 70 is set high, this application, by setting the height of the wider portion, i.e., the portion formed by the first groove segment 21, lower, can save paste to a certain extent while ensuring the welding performance of the component. This achieves both the welding performance of the component and the low resistance performance of the collector grid line 70, while also reducing costs.

[0032] The screen printing layer 10 is provided with a printing groove 20 extending along a first direction F. The extension of the printing groove 20 along the first direction F can be understood as the printing groove 20 extending along the first direction F, i.e., the first direction F is the length direction of the printing groove 20. The printing groove 20 penetrates the screen printing layer 10 along the thickness direction T. Thus, when the printing screen 100 is placed on the surface of the solar cell preform, the metal paste can enter the printing groove 20 from the thickness direction T side of the screen printing layer and be printed on the surface of the solar cell preform.

[0033] The printing groove 20 includes a plurality of first groove segments 21 and second groove segments 22 alternately connected along a first direction F. This means that multiple first groove segments 21 and second groove segments 22 are arranged alternately, and adjacent first groove segments 21 and second groove segments 22 are interconnected. Here, the maximum width of the first groove segment 21 along the second direction S is greater than the maximum width of the second groove segment 22 along the second direction S, and the minimum width of the first groove segment 21 along the second direction S is greater than or equal to the maximum width of the second groove segment 22 along the second direction S. This means that the first groove segment 21 is locally wider relative to the second groove segment 22 along the second direction S.

[0034] In some embodiments, when projected along the thickness direction T of the screen layer, the projection structure of the second groove segment 22 is rectangular. The first groove segment 21 includes two different shapes, as shown in the figure when projected along the thickness direction T of the screen layer, such as... Figure 1 As shown in the figure, the first groove segment 21 at the outermost edge of the first direction F has a projected shape that is wider in the middle and gradually narrows at both ends. The first groove segment 21 falls in the "centipede leg area". At this time, the maximum width of the first groove segment 21 along the second direction S is greater than the maximum width of the second groove segment 22 along the second direction S, and the minimum width of the first groove segment 21 along the second direction S is equal to the maximum width of the second groove segment 22 along the second direction S.

[0035] likeFigure 1 As shown in the first groove segment 21 in the middle of the first direction F, its projected structure is rectangular. At this time, the maximum width of the first groove segment 21 along the second direction S is greater than the maximum width of the second groove segment 22 along the second direction S, and the minimum width of the first groove segment 21 along the second direction S is also greater than the maximum width of the second groove segment 22 along the second direction S.

[0036] In this application, the groove depth D1 of the first groove segment 21 along the thickness direction T of the screen layer is smaller than the groove depth D2 of the second groove segment 22 along the thickness direction T of the screen layer. In actual operation, when the metal paste enters the first groove segment 21 and the second groove segment 22, it will remain in the first groove segment 21 and the second groove segment 22 due to its certain viscosity. Since the groove depth of the first groove segment 21 is smaller than the groove depth of the second groove segment 22, the height of the part formed by the first groove segment 21 is smaller than the height of the part formed by the second groove segment 22.

[0037] Please continue to combine Figure 2 and Figure 3 In some embodiments, the screen printing layer 10 includes a first side T1 and a second side T2 along the thickness direction T of the screen printing layer, with the first side T1 being the slurry inlet side. The area adjacent to the second groove segment 22 on the surface of the second side T2 of the screen printing layer 10 is flush with the area adjacent to the first groove segment 21.

[0038] In the surface of the first side T1 of the screen printing layer 10, the area adjacent to the periphery of the first groove segment 21 has a height d1 relative to the surface of the second side T2 of the screen printing layer 10 that is lower than the height d2 of the area adjacent to the periphery of the second groove segment 22 relative to the surface of the second side T2. When the area adjacent to the second groove segment 22 in the surface of the second side T2 of the screen printing layer 10 is flush with the area adjacent to the first groove segment 21, the height d1 of the area adjacent to the periphery of the first groove segment 21 relative to the surface of the second side T2 of the screen printing layer 10 is the groove depth D1 of the first groove segment 21 along the thickness direction T of the screen printing layer, and the height d2 of the area adjacent to the periphery of the second groove segment 22 relative to the surface of the second side T2 is the groove depth D2 of the second groove segment 22 along the thickness direction T of the screen printing layer. With this configuration, during printing on the screen 100, the second side T2 of the screen layer 10 can contact the surface of the solar cell preform, allowing the metal paste to enter the printing tank 20 from the first side T1 and be printed onto the surface of the solar cell preform. In the printed collector grid lines 70, the surface of the second side T2 is flush with the part formed by the first tank segment 21 and the part formed by the second tank segment 22, and the height difference between the two is reflected on the surface of the first side T1.

[0039] Please continue reading. Figure 2In some embodiments, the screen printing layer 10 includes a main layer 30 and a thickening layer 40 stacked on the main layer 30, with the thickening layer 40 located on a first side T1 of the main layer 30. A first groove segment 21 is formed in the main layer 30, and a second groove segment 22 penetrates the thickening layer 40 and the main layer 30. The thickening layer 40 can thicken the main layer 30. The second groove segment 22, in the thickness direction of the screen printing layer 10, can include a portion located in the main layer 30 and a portion located in the thickening layer 40. As long as the groove depth of the portion of the second groove segment 22 located in the main layer 30 is equal to that of the first groove segment 21, and the second groove segment 22 includes a portion located in the thickening layer 40, the groove depth of the second groove segment 22 can be greater than the groove depth of the first groove segment 21. During manufacturing, a through groove can be first opened on the main body layer 30, and then a thickening layer 40 is formed on the first side T1 of the main body layer 30. The thickening layer 40 is used to thicken the part of the through groove (corresponding to the part of the second groove segment 22). In this way, the unthickened part of the through groove forms the first groove segment 21 with a smaller groove depth, and the thickened part forms the second groove segment 22 with a larger groove depth.

[0040] It is understood that the screen printing layer 10 is a plastic film layer structure used for printing. To enhance the mechanical properties and lifespan of the screen printing layer 10, in some embodiments, the printing screen 100 further includes a skeleton structure layer 50. The skeleton structure layer 50 is stacked on the main body layer 30 and is disposed on the same side surface of the main body layer 30 as the thickening layer 40. The skeleton structure layer 50 is provided with a through ink reservoir 51, which communicates with the printing tank 20, and the width of the ink reservoir 51 along the second direction S is greater than the width of the printing tank 20 along the second direction S. For example, when projected along the thickness direction T of the screen printing layer, the projection of the ink reservoir 51 covers the projection of the printing tank 20.

[0041] The ink reservoir 51 is formed in the skeleton structure layer 50 located on the first side T1 of the screen printing layer 10. Therefore, the ink reservoir 51 is located on the first side T1 of the printing tank 20. Since the width of the ink reservoir 51 is greater than the width of the printing tank 20, when the metal paste enters the wider ink reservoir 51 from the first side T1 and then enters the printing tank 20, it is beneficial to completely fill the printing tank 20 and avoid the occurrence of grid breaks. The thickening layer 40 is located inside the ink reservoir 51, allowing part of the structure of the second tank segment 22 to enter the ink reservoir 51, facilitating the smooth entry of the metal paste in the ink reservoir 51 into the second tank segment 22.

[0042] In some embodiments, the thickening layer 40 includes a plurality of thickening portions 41, with each second groove segment 22 having a thickening portion 41 on each opposite side along the second direction S. Thus, two thickening portions 41 are respectively provided on opposite sides of the groove opening of the second groove segment 22 along the second direction S. For each thickening portion 41, the end near the skeleton structure layer 50 along the second direction S can be integrally connected to the skeleton structure layer 50, or it can be spaced apart from the skeleton structure layer 50. The surface of the thickening portion 41 near the second groove segment 22 can be flush with the surface of the main body layer 30 near the second groove segment 22, thus jointly defining a relatively continuous and smooth inner wall of the second groove segment 22. Furthermore, the thickening portion 41 can be as follows... Figure 2 As shown, it is formed into a cuboid shape, but it can also be set to other shapes as needed.

[0043] Optionally, the thickness of the thickened portion 41 along the thickness direction T of the screen layer is 1-10 micrometers. If it is greater than 10 micrometers, the height difference between the portion formed by the second trench segment 22 and the portion formed by the first trench segment 21 may be too large, affecting the welding of the collector grid line 70. If the thickness is less than 1 micrometer, the line resistance of the collector grid line 70 will be large, affecting the efficiency of the solar cell 200.

[0044] Please see Figure 2 and Figure 4 , Figure 4 This is a cross-sectional view of the printing screen 100 disclosed in this application, obtained by cutting the first groove segment 21 along a second direction. In some embodiments, the printing screen 100 further includes a reinforcing portion 60, which is disposed on the inner sidewall of the first groove segment 21. The reinforcing portion 60 is at least partially hollowed out, and the hollowed-out portion of the reinforcing portion 60 communicates with the first groove segment 21. In some embodiments, the surface of the reinforcing portion 60 has an arched structure 601. The arched structure 601 can arch in a direction away from the main body layer 30.

[0045] Considering that an excessively long printing groove 20 would affect the structural strength of the screen printing layer 10, the reinforcing portion 60 of this application is provided in the first groove segment 21 of the printing groove 20. In other words, the reinforcing portion 60 structurally reinforces the screen printing layer 10 at the first groove segment 21, thereby reducing the impact of the printing groove 20 on the structural strength of the screen printing layer 10. Furthermore, to maintain the printing continuity of the printing groove 20, the reinforcing portion 60 of this application is at least partially perforated. In other words, the metal paste can pass through the reinforcing portion 60 and be printed onto the surface of the solar cell preform to maintain the continuity of the current collector grid lines 70.

[0046] Furthermore, the reinforcing part 60 is suspended in the first groove section 21, that is, the two ends of the reinforcing part 60 along the second direction S are connected to the groove wall of the first groove section 21, and the surface of the second side T2 of the reinforcing part 60 along the thickness direction T of the screen layer is spaced relative to the surface of the second side T2 of the main body layer 30, that is, it has a suspension height h0. This is because the surface of the second side T2 of the screen layer 10 is the surface used to contact the solar cell preform. The metal paste will enter the first groove section 21 from the first side T1. If the suspension height h0 is zero or set too small, the distance between the reinforcing part 60 and the surface of the solar cell preform will be zero or too small, which may cause the metal paste to not be inkd or to be difficult to inkd. Ultimately, the part of the current collector grid line 70 formed in the first groove section 21 will have an increased proportion of broken lines.

[0047] In some other embodiments, the surface of the second side T2 of the reinforcing portion 60 along the thickness direction T of the screen layer may be flush with the surface of the second side T2 of the main body layer 30. With this configuration, the metal paste can still be applied through the cutout portion in the reinforcing portion 60, although this may make application more difficult, it simplifies the manufacturing process of the reinforcing portion 60 and saves costs. It is understood that the difficulty in applying the metal paste can also be overcome by other means, such as increasing the size of the cutout portion.

[0048] Please combine Figure 2 and Figure 4 Referring to the structure of the reinforcing part 60, it is sufficient to have at least a partial perforation. For example, the reinforcing part 60 may include a plurality of strip-shaped structures 61 spaced apart along the first direction F, with each end of the strip-shaped structure 61 located on two opposing inner sidewalls of the first groove segment 21 along the second direction S. In addition, at least a portion of the strip-shaped structure 61 arches towards the first side T1, forming the aforementioned arched structure 601, so as to enter the ink storage tank 51. Considering that the strip-shaped structure 61 is subjected to bending stress during the reciprocating motion of the squeegee during ink printing, this arched structure 601 facing the first side T1 helps to enhance the bending strength of the strip-shaped structure 61 (or the reinforcing part 60), thereby reducing the printing defect rate of the printing screen 100 on the solar cell surface corresponding to the centipede leg area, and thus improving the service life of the printing screen 100.

[0049] Secondly, embodiments of this application also disclose a method for manufacturing a printing screen, which is capable of manufacturing the printing screen 100 as described above.

[0050] Please see Figure 5 ,as well as Figures 6-22 , Figures 6-22 This is a flowchart illustrating the method for producing the printing screen disclosed in this application. Figure 2This is a schematic diagram of the various steps in the formation process of the printing screen 100 in the method for making the printing screen disclosed in this application.

[0051] Combination Figure 5 , Figures 16-20 , Figure 16 The method for producing the printing screen of this application includes the following steps: S10. Provide a screen printing plate semi-finished product 2001. The screen printing plate semi-finished product 2001 includes a main body layer 30. A through groove 201 extending along a first direction F is formed on the main body layer 30. The through groove 201 penetrates the main body layer 30 along its thickness. The through groove 201 includes a plurality of first groove segments 21 and transition groove segments 23 alternately connected along the first direction F. The maximum width of the first groove segment 21 along the second direction S is greater than the maximum width of the transition groove segment 23 along the second direction S, and the minimum width of the first groove segment 21 along the second direction S is greater than or equal to the maximum width of the transition groove segment 23 along the second direction S. The groove depth of the first groove segment 21 along the thickness direction T3 of the main body layer is equal to the groove depth of the transition groove segment 23 along the thickness direction T3 of the main body layer. The first direction F, the second direction S, and the thickness direction T3 of the main body layer are perpendicular to each other.

[0052] S20. A thickening layer 40 is formed on one side of the main layer in the thickness direction T3, and thickening layers 40 are provided on both sides of the transition groove segment 23 in the second direction S, so that the groove wall of the transition groove segment 23 and the corresponding thickening layer 40 together define the second groove segment 22, wherein the groove depth dimension of the second groove segment 22 along the thickness direction T3 of the main layer is greater than the groove depth dimension of the first groove segment 21 along the thickness direction T3 of the main layer.

[0053] In this application, a thickening layer 40 is formed on one side of the thickness direction T3 of the main layer (i.e., the thickness direction T of the aforementioned screen layer), and thickening layers 40 are correspondingly provided on both sides of the second direction S of each transition groove segment 23. This allows the groove wall of the transition groove segment 23 and the corresponding thickening layer 40 to jointly define the second groove segment 22. Therefore, the metal paste can be printed onto the solar cell preform after passing through the first groove segment 21 and the second groove segment 22 to form grid lines. Here, we take the collector grid line 70 as an example for explanation. Since the through groove 201 includes a plurality of first groove segments 21 and transition groove segments 23 alternately connected along the first direction F, and the second groove segment 22 is jointly defined by the thickening layer 40 and the first groove segment 21, the maximum width of the first groove segment 21 along the second direction S is greater than that of the transition groove segment 23, i.e., the maximum width of the second groove segment 22 along the second direction S, and the minimum width of the first groove segment 21 along the second direction S is greater than or equal to that of the transition groove segment 23, i.e., the maximum width of the second groove segment along the second direction S. This results in the maximum width of the portion formed by the first slot segment 21 in the printed collector grid line 70 being greater than the maximum width of the portion formed by the second slot segment 22, and the minimum width of the portion formed by the first slot segment 21 in the printed collector grid line 70 being greater than or equal to the maximum width of the portion formed by the second slot segment 22. Correspondingly, in the collector grid line 70, the portion formed by the first slot segment 21 is locally wider along the second direction S relative to the portion formed by the second slot segment 22.

[0054] Because the groove depth of the first groove segment 21 along the thickness direction T3 of the main layer is smaller than that of the second groove segment 22 along the thickness direction T3 of the main layer, the height of the portion of the printed collector grid line 70 formed by the first groove segment 21 is smaller than the height of the portion formed by the second groove segment 22. Consequently, the height of the locally widened portion of the collector grid line 70 is set lower than that of other portions. When it is necessary to increase the height of the collector grid line 70 to compensate for line resistance loss, this can be achieved by setting the height of the portion formed by the second groove segment 22 higher and the height of the portion formed by the first groove segment 21 lower. Compared with related technologies where the entire height of the collector grid line 70 is set high, this application, by setting the height of the wider portion, i.e., the portion formed by the first groove segment 21, lower, can save paste to a certain extent while ensuring the welding performance of the component. This achieves both the welding performance of the component and the low resistance performance of the collector grid line 70, while also reducing costs.

[0055] In this application, the thickness direction T3 of the main layer is also the thickness direction T of the aforementioned screen printing layer.

[0056] The through-slot 201 includes a plurality of first slot segments 21 and transition slot segments 23 alternately connected along a first direction F. This means that the first slot segments 21 and transition slot segments 23 are arranged alternately, and adjacent first slot segments 21 and transition slot segments 23 are interconnected. Here, the maximum width of the first slot segment 21 along the second direction S is greater than the maximum width of the transition slot segment 23 along the second direction S, and the minimum width of the first slot segment 21 along the second direction S is greater than or equal to the maximum width of the transition slot segment 23 along the second direction S. This means that the first slot segment 21 is locally wider relative to the transition slot segment 23 along the second direction S.

[0057] A thickening layer 40 is formed on one side of the main layer in the thickness direction T3, and thickening layers 40 are correspondingly provided on both sides of each transition groove segment 23 in the second direction S. The groove wall of the transition groove segment 23 and the corresponding thickening layer 40 together define the second groove segment 22. This means that after setting the thickening layer 40, the corresponding groove wall of the transition groove segment 23 is extended. The two thickening layers 40 extend the two opposite sidewalls of the transition groove segment 23 along the second direction S in a direction away from the main layer 30 to form the two opposite sidewalls of the second groove segment 22. The main layer 30 and the thickening layer 40 together form the aforementioned screen printing layer 10.

[0058] In some embodiments, please combine Figure 17 and Figure 18 In step S20, prior to the step of forming the thickened layer 40, the method further includes: A skeleton structure layer 50 is formed on the surface of the main layer on one side of the thickness direction T3. The skeleton structure layer 50 has a through-hole ink reservoir 51, which communicates with the first groove segment 21 and the transition groove segment 23. Furthermore, in the step of forming the thickening layer 40, the thickening layer 40 is located inside the ink reservoir 51. Forming the skeleton structure layer 50 first, and then setting the ink reservoir 51 within the skeleton structure, followed by forming the thickening layer 40, avoids the influence of forming the thickening layer 40 first on the skeleton structure layer 50, and facilitates precise control of the groove depth of the ink reservoir 51.

[0059] In some embodiments, in step S20, combining Figure 19 , Figure 20 , Figures 6-15 The step of forming a thickening layer 40 on the surface of the main layer on the T3 side in the thickness direction specifically includes: A mask structure 240 is provided on one side of the main body layer 30 where the skeleton structure layer 50 is located. The mask structure 240 exposes only the target area M of the main body layer 30.

[0060] On the surface of the main body layer 30 in the thickness direction, a thickened layer 40 is formed in the area not covered by the mask structure 240.

[0061] Among them, the target area M of the main body layer 30 is the part of the exposed part of the self-ink storage tank 51 of the main body layer 30 that corresponds to the transition tank section.

[0062] With this configuration, the thickened layer 40 is formed only in the portion of the main body layer 30 corresponding to the transition groove section 23, allowing the thickened layer 40 and the main body layer 30 to together form the second groove section 22 with a larger groove depth. The manufacturing process is relatively simple and can be easily manufactured using existing production line equipment.

[0063] In some embodiments, please combine Figure 6 In step S10, the step of providing the one-network version semi-finished product 2001 includes: A reinforcing portion 60 is formed on the first surface B1 in the thickness direction of the substrate 210; A main layer 30 is formed on the first surface B1. A through groove 201 extending along a first direction F is formed on the main layer 30. The through groove 201 penetrates the main layer 30 along its thickness. The through groove 201 includes a plurality of alternating first groove segments 21 and transition groove segments 23 connected along the first direction F. The maximum width of the first groove segment 21 along the second direction S is greater than the maximum width of the transition groove segment 23 along the second direction S, and the minimum width of the first groove segment 21 along the second direction S is greater than or equal to the maximum width of the transition groove segment 23 along the second direction S. The groove depth of the first groove segment 21 along the thickness direction T3 of the main layer is equal to the groove depth of the transition groove segment 23 along the thickness direction T3 of the main layer. A reinforcing part 60 is located in the first groove segment 21. By providing the reinforcing part 60, the reinforcing part 60 structurally strengthens the screen layer 10 at the location of the first groove segment 21, thereby reducing the impact of the printing groove 20 on the structural strength of the screen layer 10.

[0064] The method for producing a printing screen according to an embodiment of this application will be described below with reference to the accompanying drawings and a specific example.

[0065] The method includes the following steps: Step 1: Please refer to Figure 7 and Figure 8 A substrate 210 is provided, comprising a first surface B1 and a second surface B2 disposed opposite to each other along the thickness direction. The first surface B1 includes a first region Z1 and a second region Z2. The first region Z1 corresponds to the region in the screen printing layer 10 where a first groove segment 21 will be formed, and the second region Z2 corresponds to the region in the screen printing layer 10 where a second groove segment 22 will be formed. Furthermore, the region on the first surface B1 corresponding to the ink reservoir 51 is defined as a third region. In the projection along the thickness direction T of the screen printing layer, the projection of the ink reservoir 51 covers the through groove 201; therefore, the third region is actually configured to cover both the first region Z1 and the second region Z2.

[0066] A first conductive material layer 221 and a first mask layer 231 are sequentially formed on the first surface B1 of the substrate 210. The first conductive material layer 221 covers the entire first surface B1, while the first mask layer 231 only covers the portion of the first surface B1 corresponding to the first region Z1. The thickness of the first mask layer 231 is approximately 10 micrometers. The material of the first mask layer 231 can be UV adhesive.

[0067] Step 2: Please refer to Figure 9 and Figure 4 In the area not covered by the first mask layer 231 on the first conductive material layer 221, a second conductive material layer 222 is formed. This layer can be formed by vapor deposition, and the thickness of the second conductive material layer 222 can be 4-5 micrometers.

[0068] At this time, the height difference Δh between the surface of the second conductive material layer 222 facing away from the substrate 210 and the surface of the first mask material layer facing away from the substrate 210, i.e., the suspension height h0 of the bottom surface of the last reinforcing part 60 relative to the bottom surface of the main body layer 30 (see [reference]). Figure 10 Since the height of the first mask layer 231 cannot be precisely controlled, the height difference between the first mask layer 231 and the first conductive material layer 221 also cannot be precisely controlled. By setting the second conductive material layer 222, the height of the second conductive material layer 222 can be precisely controlled as needed. The height of the second conductive material layer 222 can be flexibly adjusted according to the actual height of the first mask layer 231, so as to achieve precise control of the suspension height h0 by precisely controlling the height difference Δh.

[0069] Step 3, please refer to Figure 11 and Figure 12 A third conductive material layer 223 is formed on both the surface of the first mask layer 231 and the surface of the second conductive material layer 222, meaning that the third conductive material layer 223 covers the entire first surface B1. The thickness of the third conductive material layer 223 is approximately a few micrometers. A second mask layer 232 is formed on the surface of the third conductive material layer 223, in which only the portion of the third conductive material layer 223 corresponding to the reinforcing portion 60 is exposed.

[0070] Step 4: Please refer to Figure 13 and Figure 14 A metallic material is formed as a reinforcement 60 in the area of ​​the third conductive material layer 223 not covered by the second mask layer 232. The second mask layer 232 is then removed to expose the third conductive material layer 223.

[0071] Step 5: Please refer to Figure 15 and Figure 16A third mask layer (not shown) is formed on one side of the third conductive material layer 223. This third mask layer covers the first region Z1 and the second region Z2 on the first surface B1, meaning it covers the areas on the first surface B1 where the first trench segment 21 and the transition trench segment 23 will be formed. The areas not covered by the third mask layer form the main body layer 30. The main body layer 30 is connected to the side of the reinforcing portion 60. The third mask layer is then cleaned and removed. A through trench 201 is formed on the main body layer 30, including the first trench segment 21 and the transition trench segment 23.

[0072] Step 8: Please refer to Figure 17 and Figure 17 A fourth mask layer is formed on the side of the main body layer 30 facing away from the substrate 210. The fourth mask layer covers the third region on the first surface B1, leaving the rest exposed. A skeleton structure layer 50 is formed on the main body layer 30 using the fourth mask layer, and then the fourth mask layer is removed. An ink reservoir 51 is provided in the skeleton structure layer 50, and the ink reservoir 51 is connected to the aforementioned through groove 201.

[0073] Step 9: Please refer to Figure 18 , Figure 19 , Figure 20 and Figure 19 A mask structure 240 is formed on the side of the skeleton structure layer 50 facing away from the substrate 210. The mask structure 240 exposes only the target area M of the main body layer 30. A thickening layer 40 is formed in the area of ​​the main body layer 30 facing away from the substrate 210 that is not covered by the mask structure 240. The thickening layer 40 is located inside the ink reservoir 51. The target area M of the main body layer 30 is the portion of the main body layer 30 exposed from the ink reservoir 51 that corresponds to the transition groove segment 23. Then, the mask structure 240 is removed. A structure is formed as shown below. Figure 20 and Figure 19 The structure shown.

[0074] Step 10: Please refer to Figure 21 , Figure 22 and Figure 23 The substrate 210, the first conductive material layer 221, the second conductive material layer 222, the third conductive material layer 223 and the first mask layer 231 are peeled off to form a printing screen 100.

[0075] Thirdly, embodiments of this application also disclose a solar cell 200.

[0076] Please see Figure 23 , ​ This is a schematic diagram of the structure of the solar cell 200 disclosed in this application. The solar cell 200 of this application includes a solar cell preform 2002 and a collector grid line 70.

[0077] A collector grid line 70 is disposed on the surface of the solar cell preform and extends along a first direction F. The collector grid line 70 includes a plurality of connecting portions 71 and carrier collecting portions 72 alternately connected along the first direction F. The maximum width of the connecting portion 71 along the second direction S is greater than the maximum width of the carrier collecting portion 72 along the second direction S, and the minimum width of the connecting portion 71 along the second direction S is greater than or equal to the maximum width of the carrier collecting portion 72 along the second direction S. The first direction F, the second direction S, and the thickness direction of the solar cell preform are perpendicular to each other. In the thickness direction of the solar cell preform (i.e., the thickness direction T of the aforementioned screen layer), the height of the connecting portion 71 is less than the height of the carrier collecting portion 72.

[0078] In this application, since the maximum width of the connecting portion 71 along the second direction S is greater than the maximum width of the carrier collecting portion 72 along the second direction S, and the minimum width of the connecting portion 71 along the second direction S is greater than or equal to the maximum width of the carrier collecting portion 72 along the second direction S, the connecting portion 71 is locally wider than the width of the carrier collecting portion 72 along the second direction S. The connecting portion 71 is the part on the collector grid line 70 used for welding or enhancing the mechanical strength of the printing screen 100, and is wider. The carrier collecting portion 72 is the part on the collector grid line 70 used for collecting carriers, and its width is smaller than that of the connecting portion 71. Since the height of the connecting portion 71 is smaller than the height of the carrier collecting portion 72, that is, the height of the wider connecting portion 71 is set lower than that of the narrower connecting portion 71, when it is necessary to increase the height of the collector grid line 70 to compensate for line resistance loss, this can be achieved by setting the height of the carrier collecting portion 72 higher, while setting the height of the connecting portion 71 lower can save paste to a certain extent while ensuring the welding performance of the component. It balances the weldability of the components and the low resistance of the collector grid 70, while also reducing costs.

[0079] It should be noted that solar cell pre-product 2002 refers to the semi-finished product of solar cell 200, such as the semi-finished product obtained after the coating process on the front and back of the solar cell.

[0080] In this application, the starting point for measuring the heights of the connecting portion 71 and the carrier collecting portion 72 in the thickness direction of the solar cell preform 2002 is the surface of the solar cell preform 2002 where the collector grid lines 70 are provided. The height of the connecting portion 71 being less than the height of the carrier collecting portion 72 means that the maximum height of the connecting portion 71 along the thickness direction is less than the minimum height of the carrier collecting portion 72 along the thickness direction.

[0081] Corresponding to the printing screen 100, the printing groove 20 is used to form the collector grid line 70, the first groove section 21 of the printing groove 20 is used to form the connecting part 71, and the second groove section 22 is used to form the carrier collection part 72.

[0082] In addition, the height of the connecting part 71 can be 1-10 micrometers higher than the height of the carrier collection part 72.

[0083] In this application, the connecting portion 71 includes a first connecting portion 711 and a second connecting portion 712. The first connecting portion 711 is the part on the collector grid line 70 used for welding to the outside, and the second connecting portion 712 is the part that strengthens the collector grid line 70. The first connecting portion 711 can be a centipede-leg grid line, and its width can gradually decrease from its two ends relative to the portion between the two ends along the second direction S. The second connecting portion 712 can be a block-shaped structure.

[0084] In some embodiments, the solar cell 200 further includes a busbar 80 extending along a second direction S. The number of collector grids 70 and busbars 80 are both multiple. The multiple busbars 80 are spaced apart along a first direction F, and the multiple collector grids 70 are spaced apart along the second direction S. Each collector grid 70 intersects with multiple busbars 80, so that the current from each collector grid 70 can be collected into the multiple busbars 80, thereby reducing current loss when a collector grid 70 experiences a grid break.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A printing screen, characterized in that The printing screen includes a screen layer; The screen layer is provided with a printing groove extending along a first direction, the printing groove penetrates the screen layer along a thickness direction of the screen layer, the printing groove includes a plurality of first groove segments and second groove segments alternately connected along the first direction, a maximum width of the first groove segment along a second direction is greater than a maximum width of the second groove segment along the second direction, and a minimum width of the first groove segment along the second direction is greater than or equal to the maximum width of the second groove segment along the second direction, wherein the first direction, the second direction and the thickness direction of the screen layer are perpendicular to each other; A groove depth dimension of the first groove segment along the thickness direction of the screen layer is less than a groove depth dimension of the second groove segment along the thickness direction of the screen layer.

2. The printing screen according to claim 1, characterized in that The screen layer includes opposite first and second sides along the thickness direction of the screen layer, and the first side is a paste entering side; In a surface of the second side of the screen layer, an area adjacent to the second groove segment is flush with an area adjacent to the first groove segment; In a surface of the first side of the screen layer, a setting height of an area adjacent to a periphery of the first groove segment relative to the surface of the second side is lower than a setting height of an area adjacent to a periphery of the second groove segment relative to the surface of the second side.

3. The printing screen according to claim 2, characterized in that The screen layer includes a main layer and a thickening layer laminated on the main layer, and the thickening layer is located on the first side of the main layer; The first groove segment is formed in the main layer, and the second groove segment penetrates the thickening layer and the main layer.

4. The printing screen according to claim 3, characterized in that The printing screen further includes a skeleton structure layer, the skeleton structure layer is laminated on the main layer, and the skeleton structure layer and the thickening layer are located on the same side surface of the main layer; The skeleton structure layer is provided with a storage groove penetratingly arranged, the storage groove is in communication with the printing groove, and a width of the storage groove along the second direction is greater than a width of the printing groove along the second direction; The thickening layer is located inside the storage groove.

5. The printing screen according to claim 3, characterized in that The thickening layer includes a plurality of thickening portions, and each second groove segment is provided with one thickening portion on each of opposite sides along the second direction.

6. The printing screen according to claim 1, characterized in that The printing screen further includes a reinforcing portion, and the reinforcing portion is arranged on an inner side wall of the first groove segment; The reinforcing portion is at least partially hollow, and the hollow part of the reinforcing portion is in communication with the printing groove; A surface of the reinforcing portion has an arch structure.

7. A method of making a printing screen, characterized in that The method includes the following steps: A screen semi-product is provided, the screen semi-product includes a main layer, the main layer is provided with a penetrating groove extending along a first direction, the penetrating groove penetrates the main layer along a thickness direction of the main layer, the penetrating groove includes a plurality of first groove segments and transition groove segments alternately connected along the first direction, a maximum width of the first groove segment along a second direction is greater than a maximum width of the transition groove segment along the second direction, and a minimum width of the first groove segment along the second direction is greater than or equal to the maximum width of the transition groove segment along the second direction, and a groove depth dimension of the first groove segment along the thickness direction of the main layer is equal to a groove depth dimension of the transition groove segment along the thickness direction of the main layer; wherein the first direction, the second direction and the thickness direction of the main layer are perpendicular to each other. A thickening layer is formed on one side surface of the main body layer in the thickness direction, and the second direction sides of each of the transition groove sections are provided with the thickening layer correspondingly, so that the groove wall of the transition groove section and the corresponding thickening layer jointly define a second groove section, wherein the groove depth of the first groove section in the thickness direction of the main body layer is smaller than the groove depth of the second groove section in the thickness direction of the main body layer.

8. The method of making a printing screen according to claim 7, wherein Before the step of forming the thickening layer, further comprising: A skeleton structure layer is formed on one side surface of the main body layer in the thickness direction, wherein the skeleton structure layer is provided with an ink storage groove arranged through, and the ink storage groove is in communication with the first groove section and the transition groove section; In the step of forming the thickening layer, the thickening layer is located inside the ink storage groove.

9. The method of making a printing screen according to claim 8, wherein The step of forming the thickening layer on one side surface of the main body layer in the thickness direction specifically comprises: A mask structure is arranged on one side of the main body layer provided with the skeleton structure layer, and the mask structure only exposes a target region of the main body layer; In the one side surface of the main body layer in the thickness direction, the region not covered by the mask structure forms the thickening layer; Wherein, the target region of the main body layer is the part corresponding to the transition groove section in the part of the main body layer exposed from the ink storage groove.

10. A solar cell, characterized by, Comprise: A solar cell pre-product; And A current collecting grid line is arranged on the surface of the solar cell pre-product and extends along a first direction, the current collecting grid line comprises a plurality of connection parts and carrier collecting parts alternately connected along the first direction, the maximum width of the connection part along a second direction is greater than the maximum width of the carrier collecting part along the second direction, and the minimum width of the connection part along the second direction is greater than or equal to the maximum width of the carrier collecting part along the second direction, wherein the first direction, the second direction and the thickness direction of the solar cell pre-product are perpendicular to each other; In the thickness direction of the solar cell pre-product, the height of the connection part is less than the height of the carrier collecting part.

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