Screen printing plate assembly

Abstract

The utility model relates to the technical field of solar cell printing screens, in particular to a printing screen assembly. The printing screen assembly comprises a first printing screen and a second printing screen. A plurality of first printing structures are arranged on the first printing screen, each first printing structure comprises a plurality of connecting grid line printing holes, and each connecting grid line printing hole is configured to be a connecting grid line for printing a solar cell. A plurality of second printing structures are arranged on the second printing screen plate, each second printing structure comprises a plurality of second grid line printing holes with full openings, and the second grid line printing holes are arranged at intervals. And in the same second printing structure, the plurality of second grid line printing holes are configured to print a plurality of local sections arranged at intervals, and every two adjacent local sections are connected through a connecting grid line to form a continuous second grid line. According to the printing screen assembly, the high printing quality and the high structural strength are both considered.

Description

Technical Field

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

[0002] The presence of wire mesh lines at the openings of the wire mesh printing plate obstructs the ink, resulting in defects such as burrs, broken lines, and incomplete printing in the printed grid lines. These defects become more severe when the line width of the grid lines narrows, making it difficult to reduce costs by printing narrower grid lines. Although narrower grid lines can be printed using a fully open printing screen, this method is prone to problems such as insufficient structural strength and poor ink flow. Utility Model Content

[0003] This application discloses a printing screen assembly that can print narrow grid lines while having high structural strength.

[0004] To achieve the above objectives, embodiments of this application disclose a printing screen assembly for a solar cell, the printing screen assembly comprising:

[0005] A first printing screen, the first printing screen having a plurality of first printing structures, each first printing structure including a plurality of connecting grid line printing holes, each of the connecting grid line printing holes being configured to print connecting grid lines of a solar cell; and

[0006] A second printing screen is provided with a plurality of second printing structures. Each second printing structure includes a plurality of fully open second grid printing holes, which are spaced apart. Each second grid printing hole has a paste inlet end, and the width of each second grid printing hole at least partially narrows from the paste inlet end along the thickness direction of the second printing screen. In the same second printing structure, the plurality of second grid printing holes are configured to print a plurality of spaced-apart partial segments, and each pair of adjacent partial segments are connected by the connecting grid lines to form a continuous second grid line.

[0007] In a possible implementation of this application, the second printing screen is a metal film printing screen, and the metal film printing screen has a multi-layer structure.

[0008] In a possible implementation of this application, the metal film printing screen includes a steel film and a steel skeleton layer stacked together. Each second grid line printing hole includes a first hole segment and a second hole segment. The first hole segment penetrates the thickness direction of the steel film, and the second hole segment penetrates the thickness direction of the steel skeleton layer and is correspondingly connected to the first hole segment. The paste inlet end is the end of the second hole segment away from the steel film. The width of the second hole segment narrows from the paste inlet end along the thickness direction of the steel skeleton layer, and the width of the first hole segment is consistent throughout.

[0009] In a possible implementation of this application, in the width direction of the second hole segment, the two opposite sidewalls of the second hole segment are inclined surfaces, and the angle between the inclined surfaces and the surface of the steel plate film is 10° to 45°.

[0010] And / or, the thickness of the steel plate film is 1μm to 15μm;

[0011] And / or, the thickness of the steel plate skeleton layer is 2μm to 15μm;

[0012] And / or, the width of the first aperture segment is 2μm to 16μm;

[0013] And / or, the width of the second aperture segment ranges from 2μm to 30μm.

[0014] In a possible implementation of this application, the length of each second gate line printed hole is 1.5mm to 15mm;

[0015] And / or, in the same second printed structure, the spacing between two adjacent second grid line printed holes is 0.01mm to 0.2mm;

[0016] And / or, a plurality of second printing structures are spaced apart on the second printing screen and the direction of the spaced arrangement is a first direction; in the first direction, the distance between two adjacent second printing structures is 0.8mm to 1.2mm; a plurality of second grid line printing holes in the same second printing structure are spaced apart along a second direction, the second direction being perpendicular to the first direction, and the second grid line printing holes extending along the second direction;

[0017] And / or, the second grid line printing hole is further configured such that the printed partial segment extends in the same direction as the connecting grid line;

[0018] And / or, the width of the connecting gate wire printing hole is greater than the width of the second gate wire printing hole.

[0019] In a possible implementation of this application, each of the first printed structures further includes a first gate line printing hole, wherein the connecting gate line printing hole intersects with the first gate line printing hole, and the first gate line printing hole is configured to print a first gate line intersecting with the plurality of connecting gate lines.

[0020] In a possible implementation of this application, the second gate line printing hole is further configured to print a portion of the local segment at the printing position of the connecting gate line, so that the local segment portion overlaps with the connecting gate line.

[0021] In a possible implementation of this application, the connecting grid line printing hole includes two oppositely arranged gradient section printing holes and an intermediate section printing hole communicating between the two gradient section printing holes;

[0022] The intermediate section printing hole intersects with the first gate line printing hole, and the intermediate section printing hole is configured to print the intermediate section of the connecting gate line;

[0023] The width of the gradient segment printing hole narrows in the direction away from the middle segment printing hole, and the two gradient segment printing holes are configured as gradient segments at both ends of the connecting grid line. The second grid line printing hole is also configured to print a portion of the local segment at the printing position of the gradient segment so that the local segment is partially overlapped with the gradient segment.

[0024] In a possible implementation of this application, the width of the end where the gradient section printed hole connects to the middle section printed hole is 45μm to 65μm;

[0025] And / or, the width of the printed hole in the gradient section away from the printed hole in the middle section is 25μm to 45μm;

[0026] And / or, the length of the printed hole for the connecting grid line is 0.8mm to 1.5mm.

[0027] In a possible implementation of this application, the number of the connecting grid line printing holes in each of the first printed structures is multiple, and the multiple connecting grid line printing holes are spaced apart along the length direction of the first grid line printing holes;

[0028] And / or, the first gate line printing hole is perpendicular to the connecting gate line printing hole;

[0029] And / or, at least one end of the first gate line printed hole is forked, and a plurality of the connecting gate line printed holes intersect with the forked portion of the first gate line printed hole.

[0030] Compared with the prior art, the beneficial effects of this application include:

[0031] In this printing screen assembly, the second grid printing hole of the second printing screen is fully open, and there is no steel wire blocking the second grid printing hole. The paste can pass through the second grid printing hole more smoothly and be printed on the solar cell, thereby reducing printing defects such as burrs, broken grids and false printing, improving printing quality, and is beneficial for printing the second grid with a narrower line width, so as to reduce the amount of paste used and reduce the production cost of solar cells.

[0032] To print the narrower linewidth of the second grid line, the width of the printing aperture for the second grid line is correspondingly narrower. To improve the ink flow through the printing aperture of the second grid line, the width of the printing aperture of the second grid line is narrower at least partially from the ink inlet end along the thickness direction of the second printing screen. That is, the width at the ink inlet end is wider. The ink enters the printing aperture of the second grid line from the wider ink inlet end, reducing the flow resistance of the ink. The ink can enter and pass through the printing aperture of the second grid line more smoothly. After the ink passes through the narrower part of the printing aperture of the second grid line, printing results in a local segment with a narrower linewidth. Thus, while printing narrower linewidth grid lines, it also has good ink flow.

[0033] To avoid the second printing screen from having excessively long, fully open second grid line printing holes that could affect its structural strength, the second printing screen is designed with an intermittent printing structure. This means the second printing structure includes multiple spaced-apart second grid line printing holes, each used to print a partial segment of the second grid line. The relatively short length of these holes helps maintain the structural strength of the second printing screen. To connect the second grid lines into a continuous shape, the first printing screen is provided with connecting grid line printing holes, which are configured to print connecting grid lines. Multiple second grid line printing holes in the same second printing structure are configured to print multiple spaced-apart partial segments, and each pair of adjacent partial segments is connected by connecting grid lines to form a continuous second grid line. In other words, by printing connecting grid lines in the first printing screen and multiple partial segments in the second printing screen to form a continuous second grid line, this printing screen assembly allows the second printing screen to maintain its structural strength by using an intermittent second printing structure.

[0034] In summary, this printing screen assembly has high structural strength and can better print narrower second grid lines, which helps to reduce the manufacturing cost of solar cells by reducing the amount of paste used. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application, the 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.

[0036] Figure 1This is a schematic diagram of the printing screen assembly disclosed in this application;

[0037] Figure 2 for Figure 1 A magnified view of region I shown in the diagram;

[0038] Figure 3 for Figure 2 The AA cross-section shown in the figure;

[0039] Figure 4 This is a schematic diagram of the printing pattern of the first printing screen disclosed in this application;

[0040] Figure 5 This is a schematic diagram of the printing pattern of the second printing screen disclosed in this application;

[0041] Figure 6 This is a schematic diagram of the structure of a solar cell printed using the printing screen assembly disclosed in this application.

[0042] Figure 7 for Figure 6 A magnified view of a portion of region II shown in the diagram;

[0043] Figure 8 This is a schematic diagram of the first printing structure disclosed in this application;

[0044] Figure 9 This is a schematic diagram of another printed pattern of the first printing screen disclosed in this application;

[0045] Figure 10 This is a schematic diagram of the structure of the solar cell disclosed in this application;

[0046] Figure 11 for Figure 10 A magnified view of a portion of region III shown in the diagram;

[0047] Figure 12 for Figure 10 Another enlarged view of region III shown;

[0048] Figure 13 for Figure 12 The BB cross-sectional view shown;

[0049] Figure 14 for Figure 12 The CC section view shown.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Printing screen assembly; 10a. First printing screen; 11. First printing structure; 111. Connecting grid line printing hole; 112. First grid line printing hole; 113. Gradient section printing hole; 114. Middle section printing hole; 115. Forked part; 10b. Second printing screen; 12. Second printing structure; 121. Second grid line printing hole; 122. Slurry inlet end; 123. First hole section; 124. Second hole section; 125. Sloping surface; 13. Steel plate film; 14. Steel plate skeleton layer; 2. Solar cell; 21. Connecting grid line; 211. Middle section; 212. Gradient section; 22. Second grid line; 221. Partial section; 23. First grid line; 24. Cell body; 241. Silicon substrate; 242. Doped layer; 243. Functional film; 25. Solar cell semi-finished product. Detailed Implementation

[0052] 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 skilled in the art without creative effort are within the scope of protection of this application.

[0053] In this application, the terms "upper," "inner," 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] Furthermore, in this application, the X0-X1 direction refers to the second direction, and the Y0-Y1 direction refers to the first direction.

[0058] The grid lines of solar cells can be fabricated using screen printing. The screen printing stencil consists of a polymer layer on a steel mesh. This polymer layer can be a latex layer covering the mesh or a PI (Polyimide) film attached to it. Patterned printing holes are created by perforating this polymer layer, which are then used to print the grid line structure. It's important to understand that these patterned printing holes only remove the corresponding areas of the polymer layer; the steel wires of the stencil remain within them. When the ink passes through these holes, these wires obstruct its flow, affecting the grid line morphology and potentially resulting in defects such as burrs, broken grid lines, and incomplete printing. These defects become more severe when the grid line width is narrower. In other words, the presence of the wires limits the cost reduction achieved by printing narrower grid lines using the screen printing stencil.

[0059] Fully open printing screens feature fully open printing holes, eliminating the wire barrier that obstructs the ink flow. This allows for smoother ink passage, resulting in better lineform and facilitating the printing of finer lines, thus reducing costs. However, when the line width is narrow, the width of the printing holes must also be narrow, making it difficult for ink to enter and pass through. Furthermore, longer lineforms require a longer area of ​​opening on the screen, which in turn affects its structural strength.

[0060] Based on the above analysis, this application discloses a printing screen assembly for a solar cell. In this assembly, the second grid line printing holes of the second printing screen are fully open. The ink can pass more smoothly through the second grid line printing holes and be printed onto the solar cell, thereby reducing printing defects such as burrs, broken grids, and incomplete printing, improving printing quality, and facilitating the printing of narrower second grid lines. To avoid the fully open second grid line printing holes being too long and affecting the structural strength of the second printing screen, this printing screen assembly forms continuous second grid lines by printing multiple local segments connecting the grid lines in the first printing screen and in the second printing screen. This allows the second printing screen to maintain its structural strength by setting intermittent second printing structures. Furthermore, the width of at least partially narrowing the second grid line printing holes of the second printing screen from the ink inlet end along the thickness direction of the second printing screen facilitates the smooth entry and passage of ink through the second grid line printing holes even when printing narrower second grid lines. In summary, this printing screen assembly has high structural strength and can print grid lines with narrow linewidths, which helps to reduce the manufacturing cost of solar cells by reducing the amount of paste used.

[0061] The technical solution of this utility model will be described below with reference to the embodiments and accompanying drawings.

[0062] To achieve the above objectives, firstly, such as Figure 1 As shown in the figure, this application discloses a printing screen assembly 1 for a solar cell. The printing screen assembly 1 includes a first printing screen 10a and a second printing screen 10b.

[0063] Please combine Figure 1 and Figure 4 The first printing screen 10a is provided with a plurality of first printing structures 11, each of which includes a plurality of connecting grid line printing holes 111, and each connecting grid line printing hole 111 is configured to print the connecting grid line 21 of the solar cell.

[0064] Please combine Figures 1 to 3 The second printing screen 10b is provided with a plurality of second printing structures 12, each of which includes a plurality of fully open second grid line printing holes 121. The plurality of second grid line printing holes 121 are spaced apart. Each second grid line printing hole 121 has a paste inlet end 122. The width of the second grid line printing hole 121 at least partially narrows from the paste inlet end 122 along the thickness direction of the second printing screen 10b.

[0065] Please combine Figure 1 , Figure 5 and Figure 6 In the same second printing structure 12, a plurality of second grid printing holes 121 are configured to print a plurality of spaced local segments 221, and each pair of adjacent local segments 221 are connected by connecting grid lines 21 to form a continuous second grid line 22.

[0066] It should be noted that there is no specific printing order between the first printing screen 10a and the second printing screen 10b. Please refer to... Figure 4 and Figure 5 For example, the printing screen assembly 1 first prints connecting grid lines 21 on the solar cell semi-finished product 25 using a first printing screen 10a, and then prints multiple partial segments 221 on the solar cell semi-finished product 25 with the connecting grid lines 21 printed using a second printing screen 10b; or, for another example, the printing screen assembly 1 first prints multiple partial segments 221 on the solar cell semi-finished product 25 using a second printing screen 10b, and then prints connecting grid lines 21 on the solar cell semi-finished product with the partial segments 221 printed using a first printing screen 10a. Here, the solar cell semi-finished product 25 refers to a solar cell on the production line where the grid lines have not yet been completed, such as a solar cell semi-finished product 25 after coating, or a solar cell semi-finished product 25 where only one side has grid lines, but the other side has not.

[0067] On the other hand, the number of first printing structures 11 on the first printing screen 10a can be one or more; the number of connecting grid printing holes 111 in each first printing structure 11 can be one or more, preferably multiple; the number of second printing structures 12 on the second printing screen 10b can be one or more, preferably multiple; the embodiments of this application do not limit this.

[0068] In this embodiment, the second grid line printing hole 121 of the second printing screen 10b is fully open. The term "fully open" refers to an opening formed after all material within the opening area has been removed along the thickness direction of the second printing screen 10b. However, this does not exclude the possibility of unavoidable residual material within the opening area, such as residual material at the edge of the opening area. The opening rate of the fully open second grid line printing hole 121 is generally 100%. In contrast, the wire mesh screen in related technologies only removes part of the material within the opening area, for example, only removing the polymer material, but retaining the wire. Compared to this, the fully open second grid line printing hole 121 has no wire obstruction, allowing the paste to pass more smoothly through the second grid line printing hole 121 and be printed onto the solar cell 2. This enables the printing of narrower second grid lines 22, while reducing printing defects such as burrs, broken grids, and incomplete printing, improving printing quality, and reducing paste consumption to lower the production cost of the solar cell 2.

[0069] To print the narrower linewidth of the second grid line 22, the width of the second grid line printing hole 121 is correspondingly narrower. To improve the ink flow through the second grid line printing hole 121, the width of the second grid line printing hole 121 narrows at least partially from the ink inlet end 122 along the thickness direction of the second printing screen 10b. This can be understood as: the width of the second grid line printing hole 121 narrows partially from the ink inlet end 122 along the thickness direction of the second printing screen 10b; or it can be understood as the overall width of the second grid line printing hole 121 narrowing from the ink inlet end 122 along the thickness direction of the second printing screen 10b. In other words, the width of the ink inlet end 122 is wider. It is understandable that the paste enters the second grid line printing hole 121 from the wider paste inlet 122. The flow resistance of the paste is small, and the paste can enter and pass through the second grid line printing hole 121 more smoothly. After the paste passes through the narrowing part of the second grid line printing hole 121, printing can obtain a local segment 221 with a narrower line width. Thus, while printing grid lines with a narrower line width, it also has good paste passage.

[0070] Furthermore, to avoid the second grid line printing holes 121 being too long and affecting the structural strength of the second printing screen 10b, the second printing screen 10b designs the second printing structure 12 as an intermittent structure. That is, the second printing structure 12 includes multiple spaced-apart second grid line printing holes 121. Each second grid line printing hole 121 is used to print a partial segment 221 of the second grid line 22. The term "partial segment 221" refers to a partial second grid line 22, such as a second grid line 22 of a partial length. It can be understood that since only a partial second grid line 22 needs to be printed, the size of each second grid line printing hole 121 is relatively small, that is, the opening size on the second printing screen 10b is small, which is beneficial to maintaining the structural strength of the second printing screen 10b.

[0071] To connect the second grid lines 22 into a continuous shape, the first printing screen 10a is provided with connecting grid line printing holes 111, which are configured to print connecting grid lines 21. Multiple second grid line printing holes 121 in the same second printing structure 12 are configured to print multiple spaced-apart partial segments 221, and each pair of adjacent partial segments 221 is connected by connecting grid lines 21 to form a continuous second grid line 22. That is, in the same second printing structure 12, if two adjacent second grid line printing holes 121 print partial segments 221 at their respective printing positions on the connecting grid lines 21, then these two partial segments 221 will be connected together by the intermediate connecting grid line 21. In other words, by printing connecting grid lines 21 in the first printing screen 10a and multiple partial segments 221 in the second printing screen 10b to form a continuous second grid line 22, the second printing screen 10b can maintain its structural strength by providing intermittent second printing structures 12.

[0072] In summary, the printing screen assembly 1 has high structural strength and can better print the narrower second grid lines 22, which helps to reduce the manufacturing cost of the solar cell 2 by reducing the amount of paste used.

[0073] The second printing screen is described in detail below.

[0074] In some embodiments, please refer to Figures 1 to 3 The second printing screen 10b is a metal film printing screen. The term "metal film printing screen" refers to a printing screen made of metal film. Metal film printing screens have good toughness, strength, and processability. It is understood that, unlike wire mesh screens, the metal portion of a metal film printing screen is a solid structure, while the metal portion of a wire mesh screen is a mesh structure. Accordingly, by making holes in the solid structure of the metal film printing screen and removing the metal material in the hole area along the thickness direction of the metal film printing screen, a fully open second grid line printing hole 121 can be obtained.

[0075] For example, the metal film printing screen can be a steel film printing screen, an aluminum film printing screen, or a titanium alloy film printing screen, etc. As another example, the second printing screen 10b can also be a polymer film printing screen.

[0076] Optionally, the metal film printing screen has a multi-layer structure. A multi-layer structure can refer to the metal film printing screen having multiple layers in its thickness direction, such as... Figure 3 The Z0-Z1 direction is shown in the diagram. A multi-layer structure refers to a metal film printing screen with two or more layers; however, this application does not limit this. Multi-layer metal film printing screens can be obtained by combining film layers of different properties to achieve composite characteristics. For example, one film layer in the metal film printing screen may have high strength, while another film layer may have high aperture precision. The resulting metal film printing screen, after combining the two layers, possesses both high strength and high aperture precision.

[0077] Specific reference Figure 3 In this embodiment of the application, the metal film printing screen includes a steel plate film 13 and a steel plate skeleton layer 14 stacked together. Both the steel plate film 13 and the steel plate skeleton layer 14 can be steel films. The steel plate film 13 is used to precisely open holes, while the steel plate skeleton layer 14 is used to improve the structural strength of the metal film printing screen.

[0078] Furthermore, each second grid line printing hole 121 includes a first hole segment 123 and a second hole segment 124. The first hole segment 123 penetrates the thickness direction of the steel plate film 13, and the second hole segment 124 penetrates the thickness direction of the steel plate skeleton layer 14 and is correspondingly connected to the first hole segment 123. The thickness directions of the steel plate film 13 and the steel plate skeleton layer 14 are as follows: Figure 3The Z0-Z1 direction is shown. The inlet end 122 is the end of the second perforation segment 124 away from the steel plate film 13. The width of the second perforation segment 124 narrows from the inlet end 122 along the thickness direction of the steel plate skeleton layer 14, while the width of the first perforation segment 123 is consistent throughout. Specifically, in Figure 3 In this context, the widths of the first aperture segment 123 and the second aperture segment 124 refer to their dimensions in the Y0-Y1 direction. The width of the first aperture segment 123 can be configured to match the designed linewidth of the second gate line.

[0079] In the embodiments of this application, the paste first enters the second aperture segment 124 through the paste inlet 122. The width of the paste inlet 122 can be greater than the design linewidth of the local segment. The remaining part of the second aperture segment 124 is then narrowed to match the design linewidth of the local segment. Then, the paste enters the first aperture segment 123 and is printed onto the solar cell. The width of the first aperture segment 123 can match the design linewidth of the local segment. The printed local segment has a consistent width in its thickness direction, resulting in a better morphology of the local segment.

[0080] Optionally, in the width direction of the second hole segment 124, i.e. Figure 3 In the Y0-Y1 direction, the two opposite sidewalls of the second hole section 124 are inclined surfaces 125. The inclined surfaces 125 can better guide the slurry through and are easy to process.

[0081] Of course, in the width direction of the second hole section, the two opposite sidewalls of the second hole section can also be stepped surfaces or curved surfaces.

[0082] Preferably, the angle α between the aforementioned inclined surface 125 and the surface of the steel plate film 13 is 10° to 45°, including any value within this range, such as 10°, 25°, or 45°. The surface of the steel plate film 13 refers to the surface perpendicular to the steel plate film 13. Figure 3 The surface in the Z0-Z1 direction. The inclined surface 125 within this included angle range allows the slurry to pass more smoothly through the second orifice 124.

[0083] It should be noted that if the thickness of the stencil film 13 is less than 1 μm, the depth of the first aperture segment 123 will be insufficient, affecting the morphology of the second grid line 22. If the thickness of the stencil film 13 is greater than 15 μm, it will lead to a decrease in the opening accuracy of the first aperture segment 123. The thickness of the stencil film 13 is 1 μm to 15 μm, including any value within this thickness range, such as 1 μm, 5 μm, or 15 μm. Stencil films 13 with this thickness range have high opening accuracy and are conducive to printing the second grid line 22 with a good morphology.

[0084] It should be noted that if the thickness of the steel plate skeleton layer 14 is less than 3μm, the overall thickness of the metal film printing screen will be too thin and its strength insufficient. If the thickness of the steel plate skeleton layer 14 is greater than 10μm, since the depth of the second aperture segment 124 is equal to the thickness of the steel plate skeleton layer 14, the second aperture segment 124 will be too deep, leading to excessive ink consumption and high ink flow resistance. Preferably, the thickness of the steel plate skeleton layer 14 is 2μm to 15μm, including any value within this range, such as 3μm, 6μm, or 10μm, so that the metal film printing screen has strong structural strength while consuming less ink and reducing ink flow resistance.

[0085] Preferably, the width of the first aperture segment 123 is 2μm to 16μm, including any value within this width range, such as 2μm, 8μm or 16μm. The printed local segment 221 has a narrower line width, thereby reducing the amount of paste used and reducing the production cost of the solar cell 2. In addition, the light-shielding area of ​​the local segment 221 is reduced, which is beneficial to the efficiency of the solar cell 2.

[0086] Preferably, the width of the second orifice 124 is in the range of 2μm to 30μm, including any value within this width range, such as 2μm, 10μm or 30μm, which facilitates the entry and passage of slurry through the second orifice 124.

[0087] Refer to the return Figure 1 and Figure 2 In the embodiments of the application, a plurality of second printing structures 12 are spaced apart on the second printing screen 10b, and the direction of the spaced arrangement is a first direction, such as... Figure 1 and Figure 2 The Y0-Y1 direction is shown. Multiple second grid line printed holes 121 in the same second printed structure 12 are spaced apart along the second direction, as shown in the second direction... Figure 1 The X0-X1 direction shown is perpendicular to the first direction. The second grid printing holes 121 of each second printing structure 12 are parallel or substantially parallel to avoid the second grid printing holes 121 intersecting, which helps to protect the structure of the second printing screen 10b.

[0088] It is understandable that if the spacing between two adjacent second printing structures 12 is too close, the structural strength of the second printing screen 10b will decrease due to excessively dense openings. If the spacing between two adjacent second printing structures 12 is too far, the printed local segments will be sparsely distributed, which is not conducive to current collection. Preferably, in the first direction, the spacing D2 between two adjacent second printing structures 12 is 0.8 mm to 1.2 mm, including any value within this spacing range, such as 0.8 mm, 1.0 mm, or 1.2 mm. When the spacing of the second printing structures 12 meets the above-mentioned spacing range, the structural strength of the second printing screen 10b is relatively better, and the printed local segments are more densely distributed, which is beneficial to current collection.

[0089] It should be noted that if the length of the second grid line printing hole 121 is less than 1.5 mm, then in order to print the required length of the second grid line, the number of second grid line printing holes 121 will be large, and the number of local segments will increase accordingly, increasing the difficulty of connecting multiple local segments into a continuous second grid line. If the length of the second grid line printing hole 121 is greater than 15 mm, it will cause a decrease in the structural strength of the second printing screen 10b. Preferably, the length of each second grid line printing hole 121 is 1.5 mm to 15 mm, including any value within this length range, such as 1.5 mm, 10 mm, 12 mm, or 15 mm. This is beneficial for maintaining the structural strength of the second printing screen 10b and reduces the difficulty of forming a continuous second grid line from multiple local segments by reducing the number of local segments. Specifically, in Figure 1 and Figure 2 In this context, the length of the second grid line printing hole 121 refers to the dimension of the second grid line printing hole 121 in the X0-X1 direction.

[0090] Reference Figure 2 Preferably, in the same second printing structure 12, the spacing D1 between two adjacent second grid line printing holes 121 is 0.01mm to 0.2mm, including any value within this spacing range, such as 0.01mm, 0.1mm or 0.2mm. This can prevent the multiple second grid line printing holes 121 in the second printing structure 12 from being too densely distributed, which is beneficial to maintaining the structural strength of the second printing screen.

[0091] See also Figure 1 and Figure 7 Preferably, the second grid line printing hole 121 is further configured such that the printed partial segment 221 extends in the same direction as the connecting grid line 21. For example... Figure 7 In this configuration, both the local segment 221 and the connecting grid line 21 extend along the X0-X1 direction. That is, the length direction of the local segment 221 is in the same direction as the length direction of the connecting grid line 21, so that the local segment 221 and the connecting grid line 21 are connected to form a continuous strip-shaped second grid line 22.

[0092] Preferably, the width of the connecting gate line printed hole 111 is greater than the width of the second gate line printed hole 121. Specifically, when the width of the connecting gate line printed hole 111 varies, the fact that the width of the connecting gate line printed hole 111 is greater than the width of the second gate line printed hole 121 can be understood as: the width of the narrowest point of the connecting gate line printed hole 111 is greater than the width of the second gate line printed hole 121. Please refer to [the relevant documentation] for details. Figure 1 and Figure 7 The purpose of the above design is that when the partial segment 221 printed by the second grid printing hole 121 deviates in its width direction, because the connecting grid line 21 is wider, the slightly deviated partial segment 221 can still be connected to the connecting grid line 21. The width direction of the partial segment 221 is as follows: Figure 7 The Y0-Y1 direction is shown in the diagram. In other words, the above design can reduce the printing accuracy requirements for the second gate line printing hole 121.

[0093] The first printing screen is described in detail below.

[0094] In some embodiments, please combine Figure 8 and Figure 9 Each first printing structure 11 also includes a first grid line printing hole 112, with the connecting grid line printing hole 111 intersecting with the first grid line printing hole 112. The first grid line printing hole 112 is configured to print the first grid line 23 that intersects with the connecting grid line 21. The connecting grid line 21 and the first grid line 23 are printed together, thereby optimizing the required number of printing screens and process steps.

[0095] Optionally, refer to Figure 8 The first gate line printing hole 112 is perpendicular to the connecting gate line printing hole 111. Specifically, in Figure 8 In this configuration, the first gate line printed hole 112 extends along the Y0-Y1 direction, and the connecting gate line printed hole 111 extends along the X0-X1 direction, with the Y0-Y1 direction being perpendicular to the Y0-Y1 direction. When the partial segment 221 printed in the second gate line printed hole 121 extends in the same direction as the connecting gate line 21, the second gate line 22 formed by the partial segment 221 will necessarily be perpendicular to the first gate line 23, thereby efficiently transmitting current.

[0096] Furthermore, please combine Figure 8 and Figure 9 At least one end of the first grid line printed hole 112 is forked, meaning either one end of the first grid line printed hole 112 is forked, or both ends of the first grid line printed hole 112 are forked. A plurality of connecting grid line printed holes 111 intersect with the forked portions 115 of the first grid line printed hole 112. It should be noted that if the first grid line 23 is too close to the edge of the solar cell 2, it can cause stress on the end of the first grid line 23 during the flow and lamination processes after welding, leading to breakage. Therefore, having at least one forked end of the first grid line 23 printed from the first grid line printed hole 112 can reduce the problems of microcracks and breakage caused by welding the first grid line 23.

[0097] Furthermore, please combine Figure 10 and Figure 11The second grid line printing hole is also configured to print a partial segment 221 at the printing position of the connecting grid line 21, so that the partial segment 221 is partially stacked with the connecting grid line 21. It is understood that since the connecting grid line 21 is printed together with the first grid line 23, i.e., the height of the connecting grid line 21 and the first grid line 23 is the same, and the partial segment 221 is partially stacked with the connecting grid line 21, the height of the stacked area must be greater than the height of the first grid line 23. It should be noted that without the padding effect at the stacked area, the solder ribbon is prone to react with the metal components of the first grid line 23. During soldering, the first grid line 23 may be broken, leading to grid breakage. The circuit of the solar cell 2 cannot conduct, and current cannot be collected normally, thus affecting the efficiency and yield of the photovoltaic module. Therefore, in the embodiment of this application, since the height of the stacked area is greater than the height of the first grid line 23... During welding, the solder strip contacts the aforementioned stacked area. Due to the raised effect of the stacked area, the solder strip is less likely to react with the first grid line 23, thereby reducing the risk of grid breakage in the first grid line 23 and improving the efficiency and yield of the photovoltaic module.

[0098] More specifically, refer to the return Figure 8 The connecting grid line printing hole 111 includes two oppositely arranged gradient section printing holes 113 and an intermediate section printing hole 114 connecting the two gradient section printing holes 113.

[0099] The intermediate section printing hole 114 intersects with the first grid line printing hole 112, and the intermediate section printing hole 114 is configured to print the intermediate section 211 of the grid line 21.

[0100] The width of the gradient section printing hole 113 narrows in the direction away from the middle section printing hole 114. The two gradient section printing holes 113 are configured to connect the gradient sections 212 at both ends of the grid line 21. The second grid line printing hole 121 is also configured to print a partial section 221 at the printing position of the gradient section 212, so that the partial section 221 is partially overlapped with the gradient section 212.

[0101] Understandable, please refer to Figure 8 and Figure 11 The connecting grid printing hole 111 is a type of printing hole that narrows from the middle to both ends. Correspondingly, the printed connecting grid line 21 also narrows from the middle to both ends. This shape of the connecting grid line 21 helps the local segment 221 to form good contact with the first grid line 23 during printing, which is beneficial for the conduction of current. The offset during soldering can be within the overlap range. Due to the presence of the connecting grid line 21, the problem of pattern offset of the local segment 221 during the printing process can be solved, that is, the local segment 221 is allowed to offset within a certain range during printing and can still overlap with the first grid line 23.

[0102] Preferably, refer to Figure 8The width W1 of the end of the gradient section printing hole 113 connected to the middle section printing hole 114 is 45μm to 65μm, including any value within this range, such as 45μm, 55μm, or 65μm. The width W2 of the end of the gradient section printing hole 113 away from the middle section printing hole 114 is 25μm to 45μm, including any value within this range, such as 25μm, 35μm, or 45μm. When the gradient section printing hole 113 meets the above width range, the wet weight of the paste during printing of the gradient section printing hole 113 is lower, the printed gradient section has a better overlap effect, and the wider gradient section can reduce the phenomenon of grid breakage.

[0103] Preferably, the length L1 of the printing hole 111 for the connecting grid line is 0.8mm to 1.5mm, including any value within this length range, such as 0.8mm, 1.0mm, or 1.5mm. When the printing hole 111 for the connecting grid line meets the above length range, the wet weight of the paste during printing is reduced, and the printed connecting grid line can effectively reduce the weld segment phenomenon during welding, while the light-blocking area is also smaller.

[0104] Optionally, refer to Figure 8 Each first printed structure 11 has multiple connecting grid line printing holes 111, which are spaced apart along the length of the first grid line printing holes 112. During printing, multiple second grid lines 22 are printed through multiple connecting grid line printing holes 111 to form multiple connecting grid lines 21, which intersect with a first grid line 23.

[0105] Secondly, such as Figure 10 and Figure 11 As shown, this application discloses a solar cell 2, which is manufactured by a printing screen assembly as described in the first aspect.

[0106] The solar cell 2 includes a cell body 24 and a plurality of second grid lines 22 and a plurality of connecting grid lines 21 disposed on the cell body 24.

[0107] The second grid line 22 includes a plurality of spaced local segments 221, with each pair of adjacent local segments 221 located at both ends of one of the connecting grid lines 21, and each pair of adjacent local segments 221 connected by the connecting grid lines 21 to form a continuous second grid line 22.

[0108] The second grid line 22 of the solar cell 2 has an intermittent structure. Accordingly, during the printing process, the solar cell 2 forms a continuous second grid line 22 by printing the connecting grid line 21 in the first printing screen and multiple local segments 221 in the second printing screen, so that the second printing screen can maintain its structural strength by setting an intermittent second printing structure.

[0109] Preferably, the linewidth of each local segment 221 is 5μm to 15μm, including any value within this linewidth range, such as 5μm, 10μm, or 15μm. When the local segment 221 meets the above linewidth range, the local segment 221 has a lower light-shielding area, lower silver loss, and good conductivity, which is beneficial to the cost reduction and efficiency improvement of solar cells, and the printing quality of the local segment 221 is also higher.

[0110] It is understandable that if the length of each local segment 221 is less than 2mm, the number of local segments 221 in the second grid line 22 will be large. The more local segments 221 there are, the higher the probability of failure to connect with the connecting grid line 21. If the length of each local segment 221 is greater than 15mm, the length of the printing hole of the second grid line for printing the local segment 221 will also be longer, and the structural strength of the second printing screen will be worse. Preferably, the length of each local segment 221 is 2mm to 15mm, including any value within this length range, such as 2mm, 10mm, or 15mm. When the local segment 221 meets the above length range, the probability of successful connection between the local segment 221 and the connecting grid line 21 is higher, and the structural strength of the second printing screen for printing the local segment is better.

[0111] In some embodiments, such as Figure 10 and Figure 11 As shown, the solar cell 2 also includes a plurality of first grid lines 23, and multiple connecting grid lines 21 and second grid lines 22. Each first grid line 23 intersects with multiple connecting grid lines 21. The multiple connecting grid lines 21 on the same first grid line 23 are spaced apart along the length direction of the first grid line 23, as shown in the figure. Figure 10 The Y0-Y1 direction is shown. Multiple second gate lines 22 are spaced apart along the length direction of the first gate line 23 and are connected to the first gate line 23 by multiple connecting gate lines 21.

[0112] Specifically, the first gate line 23 is the main gate, and the second gate line 22 is the sub-gate, with the main gate and sub-gate perpendicular to each other. Furthermore, the second gate line 22 extends in the same direction as the connecting gate line 21.

[0113] Along the length of the first gate line 23, the spacing between two adjacent second gate lines 22 is 0.9 mm to 1.1 mm, including any value within this spacing range, such as 0.9 mm, 1.0 mm, or 1.1 mm. When the second gate lines 22 meet the above spacing range, the distribution density of the second gate lines 22 is high, which is beneficial for the second gate lines 22 to collect current. At the same time, the second gate lines 22 can also avoid excessively large light-blocking area due to excessive distribution.

[0114] Specific reference Figure 11The width W3 of the end where the gradient segment 212 connects to the intermediate segment 211 is 55μm to 75μm, including any value within this width range, such as 55μm, 65μm, or 75μm. When the gradient segment 212 meets the above width range, the silver loss and light-shielding area of ​​the gradient segment 212 are both low, and it also has a sufficiently large width to reduce the risk of being broken during the soldering of the first gate line 23.

[0115] Optionally, the width W4 of the end of the gradient segment 212 furthest from the middle segment 211 is 30μm to 50μm, including any value within this width range, such as 30μm, 40μm, or 50μm. When the gradient segment 212 meets the above width range, the local segment 221 can still connect with the gradient segment 212 even if it deviates from the length direction of the first grid line 23 during printing, resulting in a higher overlap success rate. Furthermore, the silver consumption and light-blocking area of ​​the gradient segment 212 are both lower.

[0116] Optionally, the length L2 of each gradient segment 212 is 0.25mm to 0.6mm, including any value within this length range, such as 0.25mm, 0.4mm, or 0.6mm. When the gradient segment 212 meets the above length range, the overall light-shielding area and silver loss of the connecting grid line 21 are lower.

[0117] Optionally, the length L3 of the connecting gate line 21 is 1mm to 1.5mm, including any value within this length range, such as 1mm, 1.2mm, or 1.5mm. When the connecting gate line 21 meets the above length range, it can ensure that the local segment 221 is sufficiently far from the first gate line 23, thereby reducing the risk of the local segment 221 breaking during welding of the first gate line 23. Furthermore, the light-shielding area and silver consumption of the connecting gate line 21 are both low.

[0118] Furthermore, referring to Figures 12 to 14 The battery body 24 includes a silicon substrate 241, a doped layer 242, and a functional film 243. The doped layer 242 is disposed on the surface of the silicon substrate 241, and the functional film 243 is disposed on the side of the doped layer 242 away from the silicon substrate 241. The first gate line 23 and the connecting gate line 21 are disposed on the side of the functional film 243 away from the silicon substrate 241. Each local segment 221 passes through the functional film 243 and makes ohmic contact with the doped layer 242.

[0119] For example, the doped layer 242 may be a doped polycrystalline silicon layer, a doped amorphous silicon layer, or a diffusion layer. The functional film 243 may be a passivation film and / or an antireflection film.

[0120] Since the first gate line 23 and the connecting gate line 21 are printed together, both the first gate line 23 and the connecting gate line 21 can use non-burn-through paste. The first gate line 23 and the connecting gate line 21 do not penetrate the functional film 243; that is, the first gate line 23 and the connecting gate line 21 are located on the side of the functional film 243 facing away from the silicon substrate 241, which helps maintain the effectiveness of the functional film 243. The local segment 221 penetrates the functional film 243 and makes ohmic contact with the doped layer 242, that is, the local segment 221 contacts the doped layer 242 to achieve current collection.

[0121] Preferably, refer to Figure 13 The partial segment 221 is partially stacked with the connecting grid line 21, and the height of the stacked portion of the partial segment 221 and the connecting grid line 21 is greater than the height of the first grid line 23. During welding, the solder ribbon contacts the aforementioned stacked portion. Due to the raised effect of the stacked portion, the solder ribbon is less likely to react with the first grid line 23, thereby reducing the risk of grid breakage in the first grid line 23 and improving the efficiency and yield of the photovoltaic module.

[0122] It should be noted that when the local segment 221 is stacked on the side of the connecting grid line 21 away from the functional membrane 243, the stacked portion of the local segment 221 does not pass through the functional membrane 243, while the remaining portion of the local segment 221 passes through the functional membrane 243.

[0123] Optionally, please combine Figure 12 and Figure 13 The connecting grid line 21 includes two opposing gradient segments 212 and an intermediate segment 211 connecting the two gradient segments 212. The intermediate segment 211 intersects with the first grid line 23. The width of the gradient segments 212 narrows away from the intermediate segment 211. A partial segment 221 is stacked with the gradient segments 212, and the height of the stacked area of ​​the gradient segments 212 and the partial segment 221 is greater than the height of the first grid line 23. Due to the heightening effect at the stacking area, the solder ribbon is less likely to react with the first grid line 23, thereby reducing the risk of grid breakage in the first grid line 23 and improving the efficiency and yield of the photovoltaic module.

[0124] Specifically, the height of the first gate line 23 is 3μm to 4.5μm, including any value within this height range, such as 3μm, 4μm, or 4.5μm. When the first gate line 23 meets the above height range, the cross-sectional area of ​​the first gate line 23 is larger, which can improve the conductivity of the first gate line 23, and the silver consumption during the printing of the first gate line 23 is also lower.

[0125] The height at the overlap of the gradient section 212 and the local section 221 is 5μm to 7μm, including any value within this height range, such as 5μm, 6μm, or 7μm. When the overlap of the gradient section 212 and the local section 221 meets the above height range, the solder strip and the first gate line 23 can be effectively isolated, thereby reducing the risk of gate breakage in the first gate line 23.

[0126] Thirdly, embodiments of this application disclose a photovoltaic module, including a plurality of solar cells connected in series and / or in parallel, wherein at least one solar cell is the solar cell described in the second aspect.

[0127] 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 assembly, characterized in that, The printing screen assembly comprises: a first printing screen provided with a plurality of first printing structures, each of the first printing structures comprising a plurality of connection grid line printing holes configured to print connection grid lines of a solar cell; and a second printing screen provided with a plurality of second printing structures, each of the second printing structures comprising a plurality of second grid line printing holes with full openings, the second grid line printing holes being arranged at intervals, each of the second grid line printing holes having an inlet end, and a width of each of the second grid line printing holes being gradually reduced from the inlet end along a thickness direction of the second printing screen, and the second grid line printing holes in the same second printing structure being configured to print a plurality of locally arranged segments at intervals, and each of the locally arranged segments being connected to an adjacent segment through the connection grid line to form a continuous second grid line.

2. The printing screen assembly of claim 1, wherein, The second printing screen is a metal film printing screen, and the metal film printing screen is a multi-layer structure.

3. The printing screen assembly of claim 2, wherein, The metal film printing screen comprises a steel plate film and a steel plate skeleton layer arranged in layers, each of the second grid line printing holes comprises a first hole segment and a second hole segment, the first hole segment penetrates through the thickness direction of the steel plate film, the second hole segment penetrates through the thickness direction of the steel plate skeleton layer and is in communication with the first hole segment, the inlet end is an end of the second hole segment away from the steel plate film, the width of the second hole segment is gradually reduced from the inlet end along the thickness direction of the steel plate skeleton layer, and the width of the first hole segment is uniform.

4. The printing screen assembly of claim 3, wherein, In the width direction of the second hole segment, two opposite side walls of the second hole segment are inclined surfaces, and an included angle between the inclined surfaces and a surface of the steel plate film is 10°-45°. The thickness of the steel plate film is 1 μm-15 μm. The thickness of the steel plate skeleton layer is 2 μm-15 μm. The width of the first hole segment is 2 μm-16 μm. The width of the second hole segment ranges from 2 μm to 30 μm.

5. The printing screen assembly of claim 1, wherein, The length of each of the second grid line printing holes is 1.5 mm-15 mm. In the same second printing structure, the interval between two adjacent second grid line printing holes is 0.01 mm-0.2 mm. The plurality of second printing structures are arranged at intervals on the second printing screen, and an interval arrangement direction of the second printing structures is a first direction; in the first direction, the interval between two adjacent second printing structures is 0.8 mm-1.2 mm; and the plurality of second grid line printing holes in the same second printing structure are arranged at intervals along a second direction, the second direction being perpendicular to the first direction, and the second grid line printing holes extending along the second direction. The locally arranged segments printed by the second grid line printing holes extend in the same direction as the connection grid line. The width of the connection grid line printing hole is greater than the width of the second grid line printing hole.

6. The printing screen assembly according to any one of claims 1 to 5, characterized in that Each of the first printing structures further comprises a first grid line printing hole, the connection grid line printing hole intersects the first grid line printing hole, and the first grid line printing hole is configured to print a first grid line intersecting the plurality of connection grid lines.

7. The printing screen assembly of claim 6, wherein, The second gate line printing hole is further configured to print part of the local segment at a printing position of the connection gate line, so that the part of the local segment is laminated with the connection gate line.

8. The printing screen assembly of claim 7, wherein, The connection gate line printing hole comprises two oppositely arranged gradual change segment printing holes and an intermediate segment printing hole connected between the two gradual change segment printing holes. The intermediate segment printing hole intersects with the first gate line printing hole, and the intermediate segment printing hole is configured to print an intermediate segment of the connection gate line. The width of the gradual change segment printing hole narrows in a direction away from the intermediate segment printing hole, and the two gradual change segment printing holes are configured as gradual change segments at both ends of the connection gate line. The second gate line printing hole is further configured to print part of the local segment at a printing position of the gradual change segment, so that the part of the local segment is laminated with the gradual change segment.

9. The printing screen assembly of claim 8, wherein, The width of the gradual change segment printing hole at the end connected with the intermediate segment printing hole is 45 μm to 65 μm. And / or, the width of the gradual change segment printing hole away from the end of the intermediate segment printing hole is 25 μm to 45 μm. And / or, the length of the connection gate line printing hole is 0.8 mm to 1.5 mm.

10. The printing screen assembly of claim 6, wherein, The number of the connection gate line printing holes in each first printing structure is multiple, and the multiple connection gate line printing holes are arranged at intervals along the length direction of the first gate line printing hole. And / or, the first gate line printing hole is perpendicular to the connection gate line printing hole. And / or, at least one end of the first gate line printing hole is bifurcated, and several connection gate line printing holes intersect with the bifurcated part of the first gate line printing hole.

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