Screen printing plate and manufacturing method thereof, back contact solar cell and back contact photovoltaic module

Abstract

The invention relates to the technical field of printing screens, in particular to a printing screen, a manufacturing method of the printing screen, a back contact solar cell and a back contact photovoltaic module. The printing screen comprises a screen body. In the thickness direction of the screen printing plate main body, the screen printing plate main body is provided with two opposite screen printing plate surfaces; a thickened convex part is arranged on one screen printing plate surface of the screen printing plate main body, so that an avoiding concave part is formed on the periphery of the thickened convex part. The screen printing plate body is further provided with a printing groove corresponding to the thickened protruding part, and the printing groove penetrates through the screen printing plate body in the thickness direction of the screen printing plate body so that one end of the printing groove can be arranged on the thickened protruding part. According to the printing screen plate, the printing groove can still be well attached to the concave doping layer under the condition that the height difference exists between the doping layers of the two doping types, then ink printing is better conducted, the shape of a grid line obtained through printing is better, and printing abnormities such as grid breaking and virtual printing are fewer.

Description

Technical Field

[0001] This application relates to the field of printing screen technology, and in particular to a printing screen and its manufacturing method, a back-contact solar cell and a back-contact photovoltaic module. Background Technology

[0002] During the printing process of back-contact solar cells, the printing screen may not make good contact with the back side of the solar cell, resulting in poor grid line morphology and printing abnormalities such as grid breakage and incomplete printing. This can affect the power transmission performance of the grid lines and negatively impact the electrical performance of the back-contact solar cell. Summary of the Invention

[0003] This application discloses a printing screen and its manufacturing method, a back-contact solar cell and a back-contact photovoltaic module, which can achieve better ink application and printing, resulting in better grid line morphology and fewer printing abnormalities such as broken grids and incomplete printing.

[0004] To achieve the above objectives, in a first aspect, embodiments of this application disclose a printing screen, comprising:

[0005] The screen printing body has two screen printing surfaces disposed opposite each other along the thickness direction of the screen printing body; the screen printing body has a thickened protrusion on one of the screen printing surfaces, such that a clearance recess is formed around the thickened protrusion;

[0006] The screen printing plate body also has a printing groove corresponding to the thickened protrusion. The printing groove passes through the screen printing plate body along the thickness direction, so that one end of the printing groove is disposed on the thickened protrusion.

[0007] In a possible implementation of the first aspect, both the thickened protrusion and the printing groove are graphic structures, and the graphic area of ​​the printing groove is located within the graphic area of ​​the thickened protrusion.

[0008] In one possible implementation of the first aspect, the thickened protrusion is a micrometer-scale structure.

[0009] In one possible implementation of the first aspect, the thickness T1 of the thickened protrusion is 0.5 micrometers to 6 micrometers, so that the height difference between the thickened protrusion and the recessed portion is 0.5 micrometers to 6 micrometers.

[0010] In one possible implementation of the first aspect, along the thickness direction of the screen body, the side of the thickened protrusion facing away from the screen surface is a plane, and the end of the printing groove is exposed on the plane.

[0011] In a possible implementation of the first aspect, the thickened protrusion includes a longitudinal sub-protrusion and a plurality of transverse sub-protrusions, the transverse sub-protrusions extending along the length direction of the printing groove, the plurality of transverse sub-protrusions being spaced apart along the width direction of the printing groove, and the longitudinal sub-protrusions extending along the width direction of the printing groove and intersecting with the plurality of transverse sub-protrusions.

[0012] Each of the printing grooves is provided in correspondence with each of the transverse sub-protrusions.

[0013] In a possible implementation of the first aspect, the width W1 of the lateral sub-protrusion is 100 micrometers to 800 micrometers; and / or,

[0014] Along the width direction of the printing groove, the end of the printing groove is located at the middle of the transverse sub-protrusion; and / or,

[0015] The cross-sectional shape of the transverse sub-protrusion is square.

[0016] In one possible implementation of the first aspect, along the thickness direction of the screen body, the printing groove includes a connected paste buffer section and a paste printing section, the end of which is provided on the thickened protrusion;

[0017] Wherein, the width W2 of the slurry buffer section is greater than the width W3 of the slurry printing section.

[0018] In one possible implementation of the first aspect, the screen body further includes a first metal layer and a second metal layer stacked together, and the thickened protrusion is disposed on the side of the first metal layer opposite to the second metal layer;

[0019] Along the thickness direction of the screen printing body, the paste printing section penetrates the first metal layer and the thickened protrusion, and the paste buffer section penetrates the second metal layer.

[0020] In a possible implementation of the first aspect, the width W2 of the slurry buffer section is 50 micrometers to 200 micrometers; and / or,

[0021] The width W3 at the narrowest point of the slurry printing section is 3 micrometers to 15 micrometers; and / or,

[0022] The thickness T2 of the first metal layer is 8 micrometers to 15 micrometers; and / or,

[0023] The thickness T3 of the second metal layer is 5 micrometers to 20 micrometers.

[0024] In a possible implementation of the first aspect, a plurality of the printing grooves are spaced apart in a row along the length direction of the printing grooves; multiple rows of the printing grooves are arranged along the width direction of the printing grooves; and / or,

[0025] The opening ratio of the printing groove is greater than or equal to 80% and less than or equal to 100%.

[0026] Secondly, embodiments of this application disclose a method for manufacturing a printing screen, comprising the following steps:

[0027] A screen printing plate body is manufactured; wherein, along the thickness direction of the screen printing plate body, the screen printing plate body has two screen printing plate surfaces arranged opposite to each other; the screen printing plate body has a thickened protrusion on one of the screen printing plate surfaces, and the screen printing plate body also forms a relief recess around the thickened protrusion; the screen printing plate body has a printing groove corresponding to the area where the thickened protrusion is set, and along the thickness direction of the screen printing plate body, the printing groove penetrates the screen printing plate body, so that one end of the printing groove is set on the thickened protrusion.

[0028] In a possible implementation of the second aspect, the step of creating the main screen layout includes:

[0029] Fabrication of the thickened protrusion: Electrodepositing the thickened protrusion on an insulating substrate; wherein a first printed segment is formed on the electrodeposited thickened protrusion;

[0030] Fabrication of a first metal layer: Electrodepositing the first metal layer on the side of the thickened protrusion away from the substrate; wherein, a second printed segment is formed on the first metal layer, the second printed segment penetrates the first metal layer along the height direction of the first metal layer, and the second printed segment is connected to the first printed segment to form a paste printing segment;

[0031] Fabricating a second metal layer: Electrodepositing a second metal layer on the side of the first metal layer away from the substrate; wherein, a paste buffer section is fabricated on the second metal layer, the width W2 of the paste buffer section is greater than the width W3 of the paste printing section, and the paste buffer section and the paste printing section are connected to form the printing tank.

[0032] In a possible implementation of the second aspect, the step of fabricating the thickened protrusion includes:

[0033] Fabricating the first adhesive layer: The first adhesive layer is fabricated on the substrate; wherein the pattern of the first adhesive layer corresponds to the pattern of the thickened protrusion;

[0034] Fabrication of the first conductive layer: Deposit the first conductive layer on the side of the first adhesive layer opposite to the substrate;

[0035] Electrodeposition of the thickened protrusion: The thickened protrusion is electrodeposited on the side of the first conductive layer opposite to the substrate; wherein the first printed segment is formed without deposition on the first hollow pattern;

[0036] And / or,

[0037] The step of fabricating the first metal layer includes:

[0038] Fabricating a second adhesive layer: A second adhesive layer is fabricated on the substrate, and the second adhesive layer is fabricated outside the area where the thickened protrusion is located;

[0039] Fabricating a third adhesive layer: A third adhesive layer is fabricated on the surface of the first printed segment facing away from the substrate;

[0040] Fabrication of a second conductive layer: Deposit the second conductive layer on the side of the second adhesive layer and the thickened protrusion facing away from the substrate;

[0041] Electrodepositing the first metal layer: Electrodepositing the first metal layer on the side of the second conductive layer away from the substrate; wherein, no deposition is performed in the area where the third adhesive layer is disposed to form the second printed segment, and the second printed segment is connected to the first printed segment to form the paste printed segment;

[0042] And / or,

[0043] The step of fabricating the second metal layer includes:

[0044] Fabricating a fourth adhesive layer: The fourth adhesive layer is fabricated on the surface of the third adhesive layer that is opposite to the substrate; wherein the width of the fourth adhesive layer is greater than the width of the third adhesive layer;

[0045] Electrodeposition of the second metal layer: Electrodeposition of the second metal layer outside the first metal layer outside the fourth adhesive layer setting area; wherein, no electrodeposition is performed in the fourth adhesive layer setting area to form the slurry buffer section, and the slurry buffer section is connected to the slurry printing section to form the printing tank.

[0046] Thirdly, embodiments of this application disclose a back-contact solar cell, comprising:

[0047] A silicon substrate having a backlight surface;

[0048] A first doped layer and a second doped layer with opposite doping types are disposed at intervals on the backlight surface, and the first doped layer is recessed relative to the second doped layer along the thickness direction of the silicon substrate;

[0049] A functional film is disposed covering the first doped layer and the second doped layer on the side facing away from the silicon substrate.

[0050] An electrode structure comprising a first collector grid line and a second collector grid line, wherein the first collector grid line is obtained by screen printing as described in the first aspect, or by screen printing as described in the second aspect; the first collector grid line penetrates the functional film to form an ohmic contact with the first doped layer, and the second collector grid line penetrates the functional film to form an ohmic contact with the second doped layer.

[0051] In a possible implementation of the third aspect, the electrode structure further includes connected pads and connecting gate lines, the pads and the connecting gate lines being disposed on the side of the functional film facing away from the silicon substrate, a plurality of first collector gate lines being spaced apart along a first direction, and the connecting gate lines extending along the spacing direction of the first collector gate lines and intersecting with the plurality of first collector gate lines; and / or,

[0052] The first doped layer is an N-type doped layer, and the second doped layer is a P-type doped layer.

[0053] Fourthly, embodiments of this application disclose a back-contact photovoltaic module, including a plurality of electrically connected back-contact solar cells;

[0054] At least one of the back-contact solar cells is obtained by screen printing as described in the first aspect;

[0055] Alternatively, at least one of the current collector grid lines of the back contact solar cell is obtained by printing using a printing screen prepared by the manufacturing method described in the second aspect.

[0056] Alternatively, at least one of the back-contact solar cells is the back-contact solar cell described in the third aspect.

[0057] Compared with the prior art, the beneficial effects of this application include at least the following:

[0058] The printing screen of this application can extend into the concave area of ​​the back contact solar cell for printing through the thickened protrusion. On this basis, one end of the printing groove is set on the thickened protrusion. The printing groove can better fit the concave area of ​​the back contact solar cell, thereby better ink distribution and printing. The resulting grid line morphology is better and there are fewer printing abnormalities such as broken grids and incomplete printing.

[0059] Specifically, considering the height difference between the two types of doped layers produced by back-contact solar cells due to manufacturing processes, resulting in concave and convex regions on the back side of the solar cell, this application employs a printing screen with a thickened protrusion extending into the concave region to better conform to the concave area. Furthermore, one end of the printing groove is positioned on the thickened protrusion, allowing the printing groove to better conform to the concave region, thus improving ink application and resulting in better grid line morphology and reducing printing defects such as broken grids and incomplete printing.

[0060] Furthermore, the thickened protrusion has a recessed area around it, which can accommodate the protruding area to prevent the printing screen from being damaged by the protruding area, thus helping to extend the service life of the printing screen.

[0061] In summary, the printing screen of this application can still fit the concave area well even when the back contact of the solar cell is uneven, thus achieving better ink application and printing. The resulting grid lines have better morphology and fewer printing abnormalities such as broken grids and incomplete printing. Attached Figure Description

[0062] 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.

[0063] Figure 1 This is a bottom view of a printing screen disclosed in an embodiment of this application;

[0064] Figure 2 for Figure 1 The AA cross-section shown in the figure;

[0065] Figure 3 This is a schematic diagram of the printing screen disclosed in the embodiments of this application;

[0066] Figure 4 This is a top view of the substrate disclosed in the embodiments of this application after the first adhesive layer has been formed;

[0067] Figure 5 for Figure 4 The BB cross-section shown in the figure;

[0068] Figure 6 for Figure 5 A schematic diagram of the structure after the first conductive layer has been fabricated;

[0069] Figure 7 for Figure 6 Schematic diagram of the structure after the protrusion has been thickened by electrodeposition;

[0070] Figure 8 for Figure 7 Top view after the second and third adhesive layers have been made;

[0071] Figure 9 for Figure 8 The CC cross-section shown;

[0072] Figure 10 for Figure 9 A schematic diagram of the structure after the second conductive layer has been fabricated;

[0073] Figure 11 for Figure 10 A schematic diagram of the structure after electrodeposition of the first metal layer;

[0074] Figure 12 for Figure 11 Top view after the fourth adhesive layer has been applied;

[0075] Figure 13 for Figure 12 The DD cross-sectional view shown;

[0076] Figure 14 for Figure 13 Schematic diagram of the structure after electrodeposition of the second metal layer;

[0077] Figure 15 This is a schematic diagram of the structure of the printing screen prepared by the manufacturing method disclosed in the embodiments of this application;

[0078] Figure 16 This is a schematic diagram of the structure of a back-contact solar cell disclosed in an embodiment of this application;

[0079] Figure 17 This is a schematic diagram of the electrode structure disclosed in the embodiments of this application;

[0080] Figure 18 This is a schematic diagram of the structure of a back-contact photovoltaic module disclosed in an embodiment of this application.

[0081] Explanation of reference numerals in the attached figures:

[0082] 1. Printing screen; 10. Screen body; 101a, 101b. Screen surface; 11. Thickened protrusion; 111. Plane; 112. Longitudinal sub-protrusion; 113. Transverse sub-protrusion; 12. Recessed area; 13. Printing tank; 131. Paste buffer section; 132. Paste printing section; 1321. First printing sub-segment; 1322. Second printing sub-segment; 14. First metal layer; 15. Second metal layer; Z. Thickness direction of the screen body; Y. Width direction of the printing tank; X. Length direction of the printing tank;

[0083] 2. Substrate; 21. First adhesive layer; 211. Adhesive-free area; 22. First conductive layer; 23. Second adhesive layer; 24. Third adhesive layer; 25. Second conductive layer; 26. Fourth adhesive layer;

[0084] 3. Back contact solar cell; 31. Silicon substrate; 311. Backlighting surface; 32. First doped layer; 33. Second doped layer; 34. Functional film; 35. Electrode structure; 351. First collector grid line; 352. Second collector grid line; 353. Pad; 354. Connecting grid line; A1. Recessed region; A2. Protruding region;

[0085] 4. Electrical connectors. Detailed Implementation

[0086] 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.

[0087] In this application, the terms "upper," "inner," "outer," "lateral," and "longitudinal," 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.

[0088] 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.

[0089] Furthermore, the terms "set up," "connect," and "link" 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.

[0090] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (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, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0091] Due to manufacturing processes, the N-region of a back-contact solar cell is concave relative to the P-region. Generally, the height difference between the N-region and the P-region is between 1 micrometer and 6 micrometers.

[0092] However, printing screens in related technologies have a uniform thickness throughout, especially steel printing screens. When printing on the concave N-zone, the P-zone inevitably presses against the screen, making it difficult for the printing groove to adhere to the N-zone layer. Although the screen can deform under the pressure of the squeegee to make the printing groove fit the N-zone as closely as possible, the pressure from the P-zone causes the compressed area of ​​the screen to be easily worn and damaged.

[0093] Furthermore, due to the compression deformation of the printing screen during the printing process, after multiple printings, such as printing tens of thousands of back-contact solar cells, the deformed printing screen is difficult to return to its original shape. This leads to deformation and widening of the printing grooves, resulting in printing abnormalities such as broken grids and incomplete printing. There are also issues with excessive wet weight of the printing paste. In other words, the printing screen has a short lifespan, requiring frequent replacements, leading to high production costs and inconsistent grid line printing quality, ultimately compromising product quality.

[0094] In summary, the printing screens used in these technologies often fail to make good contact with the back side of the back-contact solar cell, resulting in poor grid line morphology and printing anomalies such as broken grids and incomplete printing. This negatively impacts the power transmission performance of the grid lines and is detrimental to the electrical performance of the back-contact solar cell. Furthermore, the printing screens have a relatively short lifespan, which hinders efforts to reduce production costs.

[0095] Based on the above analysis, the printing screen provided in this embodiment can extend into the concave region of the back contact solar cell through the thickened protrusion. Furthermore, one end of the printing groove is positioned on the thickened protrusion, allowing the printing groove to better fit the concave region, thus improving ink application and resulting in better grid line morphology and fewer printing defects such as broken grids and incomplete printing. Moreover, this printing screen exhibits minimal deformation during printing, allowing it to maintain its original shape after multiple printing cycles, resulting in a long service life and contributing to reduced production costs for back contact solar cells.

[0096] The technical solution of the present invention will now be described in conjunction with the embodiments and accompanying drawings.

[0097] Please refer to the following: Figures 1 to 3 This application discloses a printing screen 1, which includes a screen body 10.

[0098] Along the thickness direction Z of the screen body, the screen body 10 has two screen surfaces 101a and 101b arranged opposite to each other. The screen body 10 has a thickened protrusion 11 on one of the screen surfaces 101a, such that a recessed portion 12 is formed around the thickened protrusion 11.

[0099] The screen body 10 also has a printing groove 13 corresponding to the thickened protrusion 11. The printing groove 13 penetrates the screen body 10 along the thickness direction Z of the screen body, so that one end of the printing groove 13 is set on the thickened protrusion 11.

[0100] The beneficial effects of the printing screen plate 1 of this application will be explained below.

[0101] The printing screen 1 of this application can extend into the concave region A1 of the back contact solar cell 3 for printing through the thickened protrusion 11. On this basis, one end of the printing groove 13 is set on the thickened protrusion 11. The printing groove 13 can better fit the concave region A1, thereby better ink printing, resulting in better grid line morphology and fewer printing abnormalities such as broken grids and false printing.

[0102] Specifically, considering the height difference between the two doped layers of the back contact solar cell 3 due to the manufacturing process, the back of the back contact solar cell 3 has a concave region A1 and a convex region A2. To better fit the concave region A1, the printing screen 1 of this application extends into the concave region A1 through a thickened protrusion 11. Furthermore, one end of the printing groove 13 is positioned on the thickened protrusion 11, allowing the printing groove 13 to better fit the concave region A1, thus improving ink application and resulting in better grid line morphology and reducing printing abnormalities such as broken grids and incomplete printing.

[0103] Furthermore, a recessed portion 12 is formed around the thickened protrusion 11. The recessed portion 12 can accommodate the protruding area A2 to prevent the printing screen 1 from being damaged by the protruding area A2, which helps to extend the service life of the printing screen 1.

[0104] In summary, the printing screen 1 of this application can still better fit the concave area A1 of the printing groove 13 even when the back contact of the solar cell 3 is uneven, thus achieving better ink application and printing. The resulting grid lines have better morphology and fewer printing abnormalities such as broken grids and incomplete printing.

[0105] It should be noted that the aforementioned concave region A1 generally refers to the N-region of the back contact solar cell 3, while the convex region A2 generally refers to the P-region of the back contact solar cell 3. In other words, the printing screen 1 can be an N-region current collector grid printing screen 1.

[0106] Of course, the printing screen 1 can also be a printing screen 1 for the P-area collector grid lines. This is because after the collector grid lines are printed on the N-area, the height of the plane containing the N-area collector grid lines will be higher than or equal to the plane containing the P-area. Therefore, the printing screen 1 can also use the recessed portion 12 to avoid the N-area collector grid lines and use the thickened protrusion 11 to fit the P-area for printing.

[0107] The thickened protrusion 11 of this application will be described in detail below.

[0108] In some embodiments, please refer to the following: Figures 1 to 3 Both the thickened protrusion 11 and the printing groove 13 are graphic structures, and the graphic area of ​​the printing groove 13 is located within the graphic area of ​​the thickened protrusion 11.

[0109] In this way, the thickened protrusion 11 can cooperate with the graphic concave area A1. During printing, the thickened protrusion 11 and the concave area A1 cooperate with each other, which helps the printing groove 13 to align with the printing area on the concave area A1.

[0110] It should be noted that the pattern of the printing groove 13 needs to correspond to the pattern of the collector grid. The pattern of the thickened protrusion 11 corresponds to the pattern of the concave region A1.

[0111] Considering that the size of the concave region A1 is on the micrometer scale, for example, the width of the concave region A1 is hundreds of micrometers, and the height difference between the concave region A1 and the convex region A2 is several micrometers, the thickened convex part 11 is a micrometer-scale structure in this embodiment of the application.

[0112] In this application, a micron-scale structure refers to a structure with a thickness and width between 1 micrometer and 1000 micrometers. This allows the micron-scale structure to better match the dimensions of the recessed region A1, enabling the printing groove 13 to better conform to the recessed region A1 for printing.

[0113] It should be noted that the length and width of the thickened protrusion 11 are often on the order of millimeters. Therefore, the micron-level structure in this application is a general description of the thickness of the thickened protrusion 11.

[0114] Optionally, the thickness T1 of the thickened protrusion 11 is 0.5 micrometers to 6 micrometers, so that the height difference between the thickened protrusion 11 and the recess 12 is 0.5 micrometers to 6 micrometers, for example, 0.5 micrometers, 1 micrometer, 3 micrometers, or 6 micrometers. When the thickness of the thickened protrusion 11 meets the above thickness range, the thickness of the thickened protrusion 11 is consistent with the height difference between the concave region A1 and the protruding region A2, so that the thickened protrusion 11 fits exactly against the concave region A1, so that the printing groove 13 can print on the concave region A1.

[0115] Optionally, along the thickness direction Z of the screen body, the side of the thickened protrusion 11 facing away from the screen surface 101a is a plane 111, and the end of the printing groove 13 is exposed on the plane 111. The plane 111 can better fit the surface of the concave region A1 for printing, and can also avoid damaging the concave region A1.

[0116] In some embodiments, refer to Figure 1 and Figure 3 The thickened protrusion 11 includes a longitudinal sub-protrusion 112 and a plurality of transverse sub-protrusions 113. The transverse sub-protrusions 112 extend along the length direction X of the printing groove, and the plurality of transverse sub-protrusions 113 are spaced apart along the width direction Y of the printing groove. The longitudinal sub-protrusions 112 extend along the width direction Y of the printing groove and intersect with the plurality of transverse sub-protrusions 113.

[0117] Each printing groove 13 is correspondingly provided with each transverse sub-protrusion 113.

[0118] During printing, the longitudinal sub-protrusions 112 correspond to the busbar sub-regions of the concave region A1. Each transverse sub-protrusion 113 corresponds to the collector busbar sub-region of the concave region A1. In this way, the thickened protrusions 11 better match the concave region A1, which is beneficial for the alignment and printing of the printing groove 13.

[0119] Of course, the thickened protrusion 11 may not include the longitudinal sub-protrusion 112.

[0120] It should be noted that the busbar sub-region refers to the area in the concave region A1 used for printing busbars, and the collector grid sub-region refers to the area in the concave region A1 used for printing collector grids.

[0121] The printing groove 13 and the screen body 10 of this application will be described in detail below.

[0122] Optionally, the width W1 of the transverse sub-protrusion 113 in the Y direction is 100 micrometers to 800 micrometers, for example, 100 micrometers, 300 micrometers, 500 micrometers, or 800 micrometers. When the width W1 of the transverse sub-protrusion 113 meets the above-mentioned width range, the transverse sub-protrusion 113 is wide enough to maintain high structural strength even when penetrated by the printing groove 13, which is beneficial to improving the structural strength of the printing screen 1. Furthermore, the width of the transverse sub-protrusion 113 can be precisely matched with the collector grid sub-region of the concave region A1, so that the transverse sub-protrusion 113 can be precisely embedded in the collector grid sub-region of the concave region A1, reducing the risk of damage to the protruding region A2.

[0123] Considering that the cross-section of the collector grid sub-region of the concave region A1 is square, in this application, the cross-sectional shape of the lateral sub-protrusion 113 is also square. In this way, the shape of the lateral sub-protrusion 113 will match the collector grid sub-region of the concave region A1, making it easier for the lateral sub-protrusion 113 to be embedded into the collector grid sub-region of the concave region A1 for positioning, thereby enabling more precise printing.

[0124] In some embodiments, along the width direction Y of the printing groove, the end of the printing groove 13 is located at the middle of the transverse sub-protrusion 113 along the Y direction.

[0125] Because the dimensions of the transverse sub-protrusion 113 match those of the current collector grid sub-region, the middle of the transverse sub-protrusion 113 corresponds precisely to the middle of the current collector grid sub-region of the concave region A1 during printing. The end of the printing groove 13, i.e., the discharge end of the printing groove 13, is located in the middle of the transverse sub-protrusion 113. This facilitates the printing of the current collector grid line in the middle of the current collector grid sub-region, allowing the current collector grid line to contact the middle of the doped layer in the width direction. The distance between the current collector grid line and the two edges of the doped layer is approximately the same, enabling the current collector grid line to better collect photogenerated carriers, shortening the carrier transport path, and thus improving the collection efficiency of the current collector grid line for photogenerated carriers and the conversion efficiency of the back contact solar cell. In addition, by opening the printing groove 13 in the middle of the transverse sub-protrusion 113, the printing pressure of the printing head is evenly distributed on the screen body 10, thereby improving the service life of the printing screen 1.

[0126] In some embodiments, refer to Figure 2 Along the thickness direction Z of the screen body, the printing tank 13 includes a connected paste buffer section 131 and a paste printing section 132, and a thickened protrusion 11 is provided at the end of the paste printing section 132.

[0127] Among them, the width W2 of the paste buffer section 131 is greater than the width W3 of the paste printing section 132.

[0128] Understandably, the wider paste buffer section 131 is used to store paste, and the paste stored in the paste buffer section 131 can be pressed into the paste printing section 132 during the doctor blade extrusion, thereby improving the smoothness and continuity of the paste application, thus improving the printing effect of the current collector lines and reducing printing defects such as broken grids and incomplete printing. The narrower paste printing section 132 is used to print narrower current collector lines, thereby reducing the wet weight of the paste during current collector line printing. In addition, it can also improve the bifaciality of the back contact solar cells.

[0129] In some embodiments, refer to Figure 2 The main body 10 of the screen also includes a first metal layer 14 and a second metal layer 15 stacked together, and a thickened protrusion 11 is provided on the side of the first metal layer 14 away from the second metal layer 15.

[0130] Furthermore, along the thickness direction Z of the screen printing body, the paste printing section 132 penetrates the first metal layer 14 and the thickened protrusion 11, and the paste buffer section 131 penetrates the second metal layer 15.

[0131] In other words, the main body 10 of the screen adopts a layered structure, which means that the first metal layer 14 and the second metal layer 15 can be manufactured separately in order to obtain the paste printing section 132 and the paste buffer section 131 with different width dimensions.

[0132] Optionally, the width W2 of the paste buffer section 131 is 50 micrometers to 200 micrometers, for example, 50 micrometers, 100 micrometers, or 200 micrometers. When the paste buffer section 131 meets the above width range, the paste can flow smoothly into the paste buffer section 131 and be stored in the paste buffer section 131. When the squeegee presses against the surface of the screen body 10, the squeegee can extend into the paste buffer section 131 within this width range and scrape away the paste in the paste buffer section 131 to avoid excessive wet weight of the paste during printing. That is to say, the paste printed on the back contact solar cell 3 is mainly the paste in the paste printing section 132.

[0133] Optionally, the width W3 of the narrowest point of the paste printing section 132 is 3 to 15 micrometers, for example, 3 micrometers, 6 micrometers, 9 micrometers, 12 micrometers, or 15 micrometers. When the width of the narrowest point of the paste printing section 132 meets the above-mentioned width range, the narrowest point of the paste printing section 132 is narrow enough, which helps to reduce the width of the current collector lines and the large wet weight of the paste during printing. Furthermore, the narrowest point of the paste printing section 132 is not too narrow to avoid problems with poor paste flow.

[0134] Optionally, the thickness T2 of the first metal layer 14 is 8 micrometers to 15 micrometers, for example, 8 micrometers, 12 micrometers, or 15 micrometers. When the thickness of the first metal layer 14 meets the above thickness range, since the depth of the paste printing section 132 is consistent with the thickness of the first metal layer 14, the depth of the paste printing section 132 can print a collector grid line of appropriate height, so that the collector grid line has a low line resistance and the wet weight of the paste is not too high.

[0135] Optionally, the thickness T3 of the second metal layer 15 is 5 micrometers to 20 micrometers. When the thickness of the second metal layer 15 meets the above-mentioned thickness range, the second metal layer 15 is sufficiently thick, thus possessing high structural strength. Furthermore, the second metal layer 15 is not excessively thick, because the depth of the slurry buffer section 131 is consistent with the thickness of the second metal layer 15, thereby preventing the slurry buffer section 131 from becoming too deep and ensuring a shorter flow path for the slurry within the slurry buffer section 131.

[0136] For example, the first metal layer 14 and the second metal layer 15 can be made of nickel steel. Nickel steel has advantages such as high strength and corrosion resistance. Of course, the first metal layer 14 and the second metal layer 15 can also be made of other metal materials.

[0137] In some embodiments, referencing the back Figure 1 Multiple printing slots 13 are arranged in a row at intervals along the length X direction of the printing slot. The multiple rows of printing slots 13 are arranged along the width Y direction of the printing slot. In this way, the length of the spaced printing slots 13 is relatively short. Since the structural strength of the printing screen 1 is inversely proportional to the length of the printing slots 13, the structural strength of the printing screen 1 is higher and the service life is longer when the length of the printing slots 13 is shorter.

[0138] Optionally, the opening ratio of the printing tank 13 is greater than or equal to 90% and less than or equal to 100%, for example, 90%, 95%, 98%, 99% and 100%. When the opening ratio of the printing tank 13 meets the above opening ratio range, it indicates that there is very little obstruction in the printing tank 13, the paste has good throughput, and it is possible to print narrower and better-shaped current collector lines.

[0139] It should be noted that the aforementioned aperture ratio can be detected using a screen printing inspection instrument. A higher aperture ratio results in better ink flow and better printing of the current collector lines. Specifically, when the aperture ratio of the printing tank 13 is 100%, the printing tank 13 is also referred to as a fully open printing tank.

[0140] Please refer to the following: Figures 4 to 15 This application discloses a method for manufacturing a printing screen 1, including the following steps:

[0141] A screen printing body 10 is fabricated; wherein, along the thickness direction Z of the screen printing body, the fabricated screen printing body 10 has two screen printing surfaces 101a and 101b arranged opposite to each other. The screen printing body 10 has a thickened protrusion 11 on one of the screen printing surfaces 101a, and the screen printing body 10 also forms a recessed clearance 12 around the thickened protrusion 11. A printing groove 13 is correspondingly provided in the area where the thickened protrusion 11 is located on the screen printing body 10, and along the thickness direction Z of the screen printing body, the printing groove 13 penetrates the screen printing body 10, such that one end of the printing groove 13 is positioned on the thickened protrusion 11.

[0142] The beneficial effects of the manufacturing method described in this application will be explained below.

[0143] This manufacturing method involves creating a thickened protrusion 11 on the screen body 10, which extends into the concave region A1. One end of the printing groove 13 is positioned on the thickened protrusion 11, allowing the printing groove 13 to better conform to the concave region A1, thus improving ink application and resulting in better grid line morphology and fewer printing defects such as broken grids and incomplete printing. Furthermore, this printing screen 1 exhibits less deformation during printing, allowing it to maintain its original shape after multiple printings, resulting in a long service life and reducing the production cost of the back contact solar cell 3.

[0144] It should be noted that the method for making the screen body 10 with the thickened protrusion 11 can be electrodeposition, laser processing, etching, or other methods.

[0145] The following describes the steps for creating the webpage body 10 in this application.

[0146] In some embodiments, the step of creating the screen print body 10 includes:

[0147] Fabrication of the thickened protrusion 11: The thickened protrusion 11 is electrodeposited on the insulating substrate 2; wherein, a first printed segment 1321 is formed on the electrodeposited thickened protrusion 11; it is understood that the first printed segment 1321 penetrates the thickened protrusion 11.

[0148] Fabrication of the first metal layer 14: Electrodeposit the first metal layer 14 on the side of the thickened protrusion 11 away from the substrate 2; wherein, a second printed segment 1322 is formed on the first metal layer 14, and the second printed segment 1322 penetrates the first metal layer 14 along the height direction of the first metal layer 14, and the second printed segment 1322 is connected to the first printed segment 1321 to form a paste printing segment 132.

[0149] Fabrication of the second metal layer 15: Electrodeposit the second metal layer 15 on the side of the first metal layer 14 away from the substrate 2; wherein, a paste buffer section 131 is fabricated on the second metal layer 15, the width W2 of the paste buffer section 131 is greater than the width W3 of the paste printing section 132, and the paste buffer section 131 and the paste printing section 132 are connected to form a printing tank 13.

[0150] Specifically, the insulating substrate 2 is, for example, a glass substrate or a polymer material substrate. The electrodeposition method is, for example, electroforming or electroplating.

[0151] In other words, the process of making the screen printing body 10 can be divided into three steps: first, electrodepositing a thickened protrusion 11 with a first printing segment 1321; then, electrodepositing a first metal layer 14 with a second printing segment 1322 on the basis of the thickened protrusion 11; the second printing segment 1322 is connected to the first printing segment 1321 to form a paste printing segment 132.

[0152] Next, a second metal layer 15 having a paste buffer section 131 is electrodeposited on the first metal layer 14. The paste buffer section 131 and the paste printing section 132 are connected to form a printing tank 13. The final screen body 10 has a thickened protrusion 11 and a printing tank 13 corresponding to the thickened protrusion 11.

[0153] Since the thickened protrusion 11, the first metal layer 14 and the second metal layer 15 are all made by electrodeposition, the bonding strength is relatively high, which makes the screen body 10 have the characteristics of high strength and long service life.

[0154] Furthermore, please refer to the following: Figures 4 to 7 The steps for creating the thickened protrusion 11 include:

[0155] Preparation of the first adhesive layer 21: Refer to Figure 4 and Figure 5 A first adhesive layer 21 is formed on the substrate 2; wherein the pattern of the first adhesive layer 21 corresponds to the pattern of the thickened protrusion.

[0156] Fabrication of the first conductive layer 22: Refer to Figure 5 and Figure 6 A first conductive layer 22 is deposited on the side of the first adhesive layer 21 that is away from the substrate 2.

[0157] Electrodeposition thickened protrusion 11: Reference Figure 6 and Figure 7 A thickened protrusion 11 is electrodeposited on the side of the first conductive layer 22 away from the substrate 2. The first printed segment 1321 is formed on the first perforated pattern without deposition.

[0158] Specifically, the first adhesive layer 21 is, for example, a UV adhesive or other types of non-conductive adhesive. The first adhesive layer 21 is fabricated by methods such as spin coating or photolithography.

[0159] The material of the first conductive layer 22 is, for example, a nickel-based alloy or a copper alloy. The deposition method of the first conductive layer 22 is, for example, PVD (Physical Vapor Deposition).

[0160] In this embodiment, the deposition area of ​​the thickened protrusion 11 is defined by the first adhesive layer 21. Since no electrodeposited metal is required on the first printed segment 1321, the corresponding area of ​​the first printed segment 1321 does not need to be made with the first adhesive layer 21 to form an adhesive-free area 211. The first adhesive layer 21 is used to isolate the substrate 2 and the thickened protrusion 11 so that the printing screen 1 can be separated from the substrate 2 in the future.

[0161] Then, a first conductive layer 22 is formed on the first adhesive layer 21. When depositing the first conductive layer 22, a mold can be used to mask areas where electrodeposition is not required. It is understood that the pattern of the first conductive layer 22 corresponds to the pattern of the first adhesive layer 21. The first conductive layer 22 is used to provide a conductive base for the electrodeposited thickened protrusion 11.

[0162] Finally, a thickened protrusion 11 with a first printed segment 1321 is formed on the basis of the first conductive layer 22 by electrodeposition.

[0163] In this application, the first printing segment 1321 and the second printing segment are combined to form a paste printing segment, as detailed below.

[0164] Furthermore, please refer to the following: Figures 8 to 11 The steps for fabricating the first metal layer 14 include:

[0165] To create the second adhesive layer 23: Please refer to the instructions below. Figure 8 and Figure 9 A second adhesive layer 23 is formed on the substrate 2, and the second adhesive layer 23 is formed outside the setting area of ​​the thickened protrusion 11.

[0166] To create the third adhesive layer 24: Please refer to the instructions below. Figure 8 and Figure 9 A third adhesive layer 24 is formed on the surface of the first printed segment 1321 facing away from the substrate 2.

[0167] Fabrication of the second conductive layer 25: Please refer to the following: Figure 9 and Figure 10 A second conductive layer 25 is deposited on the side of the second adhesive layer 23 and the thickened protrusion 11 that is away from the substrate 2. That is, the second conductive layer 25 is not deposited only in the area where the third adhesive layer 24 is disposed.

[0168] Electrodeposition of the first metal layer 14: Please refer to the above as well. Figure 10 and Figure 11 A first metal layer 14 is electrodeposited on the side of the second conductive layer 25 away from the substrate 2; wherein, no deposition is performed in the area where the third adhesive layer 24 is disposed, and a second printed segment 1322 is formed, and the second printed segment 1322 is connected to the first printed segment 1321 to form a paste printed segment 132.

[0169] Specifically, the material and manufacturing method of the second conductive layer 25 can be referred to the first conductive layer 22, and the material and manufacturing method of the second adhesive layer 23 and the third adhesive layer 24 can be referred to the first adhesive layer 21, which will not be elaborated here.

[0170] In this embodiment, the second adhesive layer 23 is used to define the deposition area of ​​the first metal layer 14. The third adhesive layer 24 is used to define the fabrication area of ​​the second printed segment 1322. Then, a second conductive layer 25 is fabricated on the second adhesive layer 23. When depositing the second conductive layer 25, a mold can be used to shield areas where electrodeposition is not required. The second conductive layer 25 provides a conductive base for the electrodeposition of the first metal layer 14. The first metal layer 14 is electrodeposited on the side of the second conductive layer 25 and the thickened protrusion 11 facing away from the substrate 2, so that the deposited first metal layer 14 and the thickened protrusion 11 are connected, and the second printed segment 1322 is connected to the first printed segment 1321 to form the paste printed segment 132.

[0171] Furthermore, please refer to the following: Figures 12 to 15 The steps for fabricating the second metal layer 15 include:

[0172] For the fourth adhesive layer 26: please refer to the instructions as well. Figure 12 and Figure 13 A fourth adhesive layer 26 is formed on the surface of the third adhesive layer 24 facing away from the substrate 2; wherein the width of the fourth adhesive layer 26 is greater than the width of the third adhesive layer 24.

[0173] Electrodeposition of the second metal layer 15: Please refer to the above as well. Figure 13 and Figure 14 A second metal layer 15 is electrodeposited outside the first metal layer 14 outside the area where the fourth adhesive layer 26 is disposed; wherein, no electrodeposition is performed in the area where the fourth adhesive layer 26 is disposed, and a slurry buffer section 131 is formed, which is connected to the slurry printing section 132 to form a printing tank 13.

[0174] In this embodiment, the fourth adhesive layer 26 is used to define the grooved area of ​​the paste buffer section 131, so as to obtain a paste buffer section 131 that is wider than the paste printing section 132. In addition, the second metal layer 15 is electrodeposited on the first metal layer 14, so that the second metal layer 15 and the first metal layer 14 have a better bonding effect and the structural strength of the screen body 10 is higher.

[0175] For more details, the material and manufacturing method of the fourth adhesive layer 26 can be referred to the first adhesive layer 21, and will not be repeated here. In addition, after the manufacturing is completed, the first adhesive layer 21, the second adhesive layer 23, the third adhesive layer 24 and the fourth adhesive layer 26 need to be removed, for example by using a solvent and heating to melt them.

[0176] Please refer to Figure 16 and Figure 17 This application discloses a back-contact solar cell 3, which includes a silicon substrate 31, a first doped layer 32 and a second doped layer 33 with opposite doping types, a functional film 34, and an electrode structure 35.

[0177] The silicon substrate 31 has a backlight surface 311. A first doped layer 32 and a second doped layer 33 are disposed at intervals on the backlight surface 311, and the first doped layer 32 is recessed relative to the second doped layer 33 along the thickness direction of the silicon substrate 31.

[0178] The functional film 34 is disposed on the side of the first doped layer 32 and the second doped layer 33 facing away from the silicon substrate 31. The electrode structure 35 includes a first collector grid line 351 and a second collector grid line 352. The first collector grid line 351 is obtained by screen printing as disclosed in the embodiments of this application, or the first collector grid line 351 is obtained by screen printing using the manufacturing method disclosed in the embodiments of this application.

[0179] The first collector gate line 351 penetrates the functional film 34 and forms an ohmic contact with the first doped layer 32, and the second collector gate line 352 penetrates the functional film 34 and forms an ohmic contact with the second doped layer 33.

[0180] The first doped layer 32 of the back contact solar cell 3 is recessed relative to the second doped layer 33, so that the first doped layer 32 and the second doped layer 33 are staggered in the thickness direction of the silicon substrate 31, which is more conducive to the insulation and isolation between the first doped layer 32 and the second doped layer 33.

[0181] Based on this, the first collector line 351 is printed using the printing screen 1 disclosed in the embodiments of this application, or the first collector line 351 is printed using the printing screen 1 manufactured by the method disclosed in the embodiments of this application. The thickened protrusion 11 of the printing screen 1 can extend into the concave region A1 for printing. Furthermore, one end of the printing groove 13 is disposed on the thickened protrusion 11, and the printing groove 13 can better fit the concave region A1, thereby improving ink application and resulting in a better morphology of the printed first collector line 351 with fewer printing abnormalities such as broken lines and incomplete printing.

[0182] In some embodiments, the electrode structure 35 further includes connected pads 353 and connecting gate lines 354. The pads 353 and connecting gate lines 354 are disposed on the side of the functional film 34 facing away from the silicon substrate 31. Multiple first collector gate lines 351 are spaced apart along a first direction. The connecting gate lines 354 extend along the spaced direction of the first collector gate lines 351 and intersect with the multiple first collector gate lines 351. The first doped layer 32 is an N-type doped layer, and the second doped layer 33 is a P-type doped layer. The N-type doped layer is, for example, a phosphorus-doped layer or an N-type doped polysilicon layer, and the P-type doped layer is, for example, a boron-doped layer or a P-type doped polysilicon layer.

[0183] Considering that if the connecting gate line 354 is printed together with the first collector gate line 351, the connecting gate line 354 is prone to coarse gate problem.

[0184] Therefore, in this embodiment, the connecting gate line 354 is printed using a non-burn-through paste, ensuring that the connecting gate line 354 does not penetrate the functional film 34. The connecting gate line 354 is located on the side of the functional film 34 facing away from the silicon substrate 31. Since the connecting gate line 354 and the collector gate line are printed using different pastes, the connecting gate line 354 can be printed using different printing screens 1 than the collector gate line. For example, the printing groove 13 of the connecting gate line 354 can be integrated onto the bus gate printing screen 1. This helps to solve the problem of coarse gates in the connecting gate line 354, resulting in a better printed morphology of the connecting gate line 354.

[0185] Please refer to Figure 18 This application discloses a back-contact photovoltaic module, including a plurality of electrically connected back-contact solar cells 3.

[0186] At least one of the current collector grid lines of the back contact solar cell 3 is obtained by printing using the printing stencil disclosed in the embodiments of this application.

[0187] Alternatively, at least one of the current collector grid lines of the back contact solar cell 3 is obtained by printing with a printing screen made by the manufacturing method disclosed in the embodiments of this application;

[0188] Alternatively, at least one of the back-contact solar cells 3 is the back-contact solar cell 3 disclosed in the embodiments of this application.

[0189] Specifically, the back contact solar cell 3 is electrically connected in a manner such as through series and / or parallel connection of electrical connectors, and the electrical connector 4 is, for example, a solder strip, a busbar, etc.

[0190] 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, include: The screen printing body has two screen printing surfaces disposed opposite each other along the thickness direction of the screen printing body; the screen printing body has a thickened protrusion on one of the screen printing surfaces, such that a clearance recess is formed around the thickened protrusion; The screen printing plate body also has a printing groove corresponding to the thickened protrusion. The printing groove passes through the screen printing plate body along the thickness direction, so that one end of the printing groove is disposed on the thickened protrusion.

2. The printing screen according to claim 1, characterized in that, Both the thickened protrusion and the printing groove are graphic structures, and the graphic area of ​​the printing groove is located within the graphic area of ​​the thickened protrusion.

3. The printing screen according to claim 1, characterized in that, The thickened protrusion has a micron-level structure.

4. The printing screen according to claim 3, characterized in that, The thickness T1 of the thickened protrusion is 0.5 micrometers to 6 micrometers, so that the height difference between the thickened protrusion and the recessed part is 0.5 micrometers to 6 micrometers.

5. The printing screen according to claim 1, characterized in that, Along the thickness direction of the screen body, the side of the thickened protrusion facing away from the screen surface is a plane, and the end of the printing groove is exposed on the plane.

6. The printing screen according to claim 1, characterized in that, The thickened protrusion includes a longitudinal sub-protrusion and a plurality of transverse sub-protrusions. The transverse sub-protrusions extend along the length direction of the printing groove, and the plurality of transverse sub-protrusions are spaced apart along the width direction of the printing groove. The longitudinal sub-protrusions extend along the width direction of the printing groove and intersect with the plurality of transverse sub-protrusions. Each of the printing grooves is provided in correspondence with each of the transverse sub-protrusions.

7. The printing screen according to claim 6, characterized in that, The width W1 of the lateral sub-protrusion is 100 micrometers to 800 micrometers; and / or, Along the width direction of the printing groove, the end of the printing groove is located at the middle of the transverse sub-protrusion; and / or, The cross-sectional shape of the transverse sub-protrusion is square.

8. The printing screen according to claim 1, characterized in that, Along the thickness direction of the screen body, the printing groove includes a connected paste buffer section and a paste printing section, and the end of the paste printing section is provided on the thickened protrusion; Wherein, the width W2 of the slurry buffer section is greater than the width W3 of the slurry printing section.

9. The printing screen according to claim 8, characterized in that, The main body of the screen also includes a first metal layer and a second metal layer stacked together, and the thickened protrusion is disposed on the side of the first metal layer away from the second metal layer; Along the thickness direction of the screen printing body, the paste printing section penetrates the first metal layer and the thickened protrusion, and the paste buffer section penetrates the second metal layer.

10. The printing screen according to claim 9, characterized in that, The width W2 of the slurry buffer section is 50 micrometers to 200 micrometers; and / or, The width W3 at the narrowest point of the slurry printing section is 3 micrometers to 15 micrometers; and / or, The thickness T2 of the first metal layer is 8 micrometers to 15 micrometers; and / or, The thickness T3 of the second metal layer is 5 micrometers to 20 micrometers.

11. The printing screen according to any one of claims 1 to 10, characterized in that, The plurality of printing slots are spaced apart in a row along the length of the printing slots; the multiple rows of printing slots are arranged along the width of the printing slots; and / or, The opening ratio of the printing groove is greater than or equal to 90% and less than or equal to 100%.

12. A method for manufacturing a printing screen, characterized in that, Includes the following steps: A screen printing plate body is manufactured; wherein, along the thickness direction of the screen printing plate body, the screen printing plate body has two screen printing plate surfaces arranged opposite to each other; the screen printing plate body has a thickened protrusion on one of the screen printing plate surfaces, and the screen printing plate body also forms a relief recess around the thickened protrusion; the screen printing plate body has a printing groove corresponding to the area where the thickened protrusion is set, and along the thickness direction of the screen printing plate body, the printing groove penetrates the screen printing plate body, so that one end of the printing groove is set on the thickened protrusion.

13. The manufacturing method according to claim 12, characterized in that, The steps for creating the main screen layout include: Fabrication of the thickened protrusion: Electrodepositing the thickened protrusion on an insulating substrate; wherein a first printed segment is formed on the electrodeposited thickened protrusion; Fabrication of a first metal layer: Electrodepositing the first metal layer on the side of the thickened protrusion away from the substrate; wherein, a second printed segment is formed on the first metal layer, the second printed segment penetrates the first metal layer along the height direction of the first metal layer, and the second printed segment is connected to the first printed segment to form a paste printing segment; Fabricating a second metal layer: Electrodepositing a second metal layer on the side of the first metal layer away from the substrate; wherein, a paste buffer section is fabricated on the second metal layer, the width W2 of the paste buffer section is greater than the width W3 of the paste printing section, and the paste buffer section and the paste printing section are connected to form the printing tank.

14. The manufacturing method according to claim 13, characterized in that, The step of fabricating the thickened protrusion includes: Fabricating the first adhesive layer: The first adhesive layer is fabricated on the substrate; wherein the pattern of the first adhesive layer corresponds to the pattern of the thickened protrusion; Fabrication of the first conductive layer: Deposit the first conductive layer on the side of the first adhesive layer opposite to the substrate; Electrodeposition of the thickened protrusion: The thickened protrusion is electrodeposited on the side of the first conductive layer opposite to the substrate; wherein the first printed segment is formed without deposition on the first hollow pattern; And / or, The step of fabricating the first metal layer includes: Fabricating a second adhesive layer: A second adhesive layer is fabricated on the substrate, the second adhesive layer being fabricated outside the area where the thickened protrusion is located; Fabricating a third adhesive layer: A third adhesive layer is fabricated on the surface of the first printed segment facing away from the substrate; Fabrication of a second conductive layer: Deposit the second conductive layer on the side of the second adhesive layer and the thickened protrusion facing away from the substrate; Electrodepositing the first metal layer: Electrodepositing the first metal layer on the side of the second conductive layer away from the substrate; wherein, no deposition is performed in the area where the third adhesive layer is disposed to form the second printed segment, and the second printed segment is connected to the first printed segment to form the paste printed segment; And / or, The step of fabricating the second metal layer includes: Fabricating a fourth adhesive layer: The fourth adhesive layer is fabricated on the surface of the third adhesive layer that is opposite to the substrate; wherein the width of the fourth adhesive layer is greater than the width of the third adhesive layer; Electrodeposition of the second metal layer: Electrodeposition of the second metal layer outside the first metal layer outside the fourth adhesive layer setting area; wherein, no electrodeposition is performed in the fourth adhesive layer setting area to form the slurry buffer section, and the slurry buffer section is connected to the slurry printing section to form the printing tank.

15. A back-contact solar cell, characterized in that, include: A silicon substrate having a backlight surface; A first doped layer and a second doped layer with opposite doping types are disposed at intervals on the backlight surface, and the first doped layer is recessed relative to the second doped layer along the thickness direction of the silicon substrate; A functional film is disposed covering the first doped layer and the second doped layer on the side facing away from the silicon substrate. An electrode structure comprising a first collector grid line and a second collector grid line, wherein the first collector grid line is obtained by screen printing according to any one of claims 1 to 12, or the first collector grid line is obtained by screen printing according to the manufacturing method according to any one of claims 13 to 15; the first collector grid line penetrates the functional film to form an ohmic contact with the first doped layer, and the second collector grid line penetrates the functional film to form an ohmic contact with the second doped layer.

16. The back-contact solar cell according to claim 15, characterized in that, The electrode structure further includes connected pads and connecting gate lines, the pads and the connecting gate lines being disposed on the side of the functional film facing away from the silicon substrate, multiple first collector gate lines being spaced apart, and the connecting gate lines extending along the spacing direction of the first collector gate lines and intersecting with the multiple first collector gate lines; and / or, The first doped layer is an N-type doped layer, and the second doped layer is a P-type doped layer.

17. A back-contact photovoltaic module, characterized in that, Includes several electrically connected back-contact solar cells; At least one of the current collector grid lines of the back-contact solar cell is obtained by screen printing as described in any one of claims 1 to 11; Alternatively, at least one of the current collector grid lines of the back contact solar cell is obtained by screen printing using the manufacturing method as described in any one of claims 12 to 14. Alternatively, at least one of the back-contact solar cells is the back-contact solar cell as described in claim 15 or 16.

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