Printing screen and manufacturing method therefor, solar cell, and photovoltaic module

Abstract

The present application relates to the technical field of printing screens, and in particular to a printing screen and a manufacturing method therefor, a solar cell, and a photovoltaic module. The printing screen comprises a screen body and a reinforcing part. Printing grooves extending in a first direction are provided in the screen body, and the printing grooves pass through the screen body in the thickness direction thereof. The reinforcing part is arranged at the position of the screen body provided with a printing groove, the reinforcing part is arranged corresponding to part of the printing groove, at least part of the reinforcing part is hollowed out, and the hollowed-out portion of the reinforcing part is communicated with the printing groove. The printing screen combines the advantages of high printing quality and high structural strength, can print continuous current collection grid lines to facilitate current collection of the current collection grid lines, and can meet the process and testing requirements for energizing the solar cell.

Description

A printing screen and its manufacturing method, solar cells, photovoltaic modules

[0001] This application claims priority to Chinese Patent Application No. 202510080791.1, filed on January 17, 2025, entitled "A printing screen and manufacturing method, solar cell, photovoltaic module", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of screen printing technology, and more particularly to a printing screen and its manufacturing method, solar cells, and photovoltaic modules. Background Technology

[0003] The current collector lines of a solar cell can be printed using a screen printing plate. The screen printing plate has printing grooves that match the pattern of the current collector lines. However, the current collector lines are longer; for example, the length of the current collector lines is only slightly smaller than the size of the solar cell. Correspondingly, the printing grooves on the screen printing plate are also longer. Longer printing grooves can lead to a decrease in the structural strength of the screen printing plate, thus resulting in a shorter lifespan. Summary of the Invention

[0004] This application discloses a printing screen and its manufacturing method, a solar cell, and a photovoltaic module, which can take into account the advantages of high printing quality and high structural strength. It can also print continuous collector grid lines, which is beneficial for current collection by the collector grid lines, and can meet the process and testing requirements for energizing the solar cell.

[0005] To achieve the above objectives, in a first aspect, embodiments of this application disclose a printing screen, comprising:

[0006] A screen printing plate body, wherein a printing groove extending along a first direction is provided on the screen printing plate body, the printing groove penetrating the screen printing plate body along the thickness direction, and the first direction is perpendicular to the thickness direction of the screen printing plate body; and

[0007] The reinforcing part is at least partially disposed at the position where the printing groove is located on the screen body. The reinforcing part is disposed in relation to the printing groove. At least part of the reinforcing part is hollowed out and the hollowed-out part of the reinforcing part is connected to the printing groove.

[0008] In one possible implementation of the first aspect, in the second direction, the reinforcing portion is disposed between two opposite sides of the printing groove;

[0009] The second direction intersects with the first direction.

[0010] In a possible implementation of the first aspect, the printing groove has a first opening segment and a second opening segment in the first direction, and the reinforcing portion is located between the first opening segment and the second opening segment.

[0011] In one possible implementation of the first aspect, the reinforcing part includes at least one of a finger structure, a mesh structure, a honeycomb structure, a ring structure, or a polygonal structure.

[0012] In a possible implementation of the first aspect, the reinforcing part has a plurality of linear substructures, which are spaced apart to form a hollow area; or, the plurality of linear substructures are connected to form a hollow area; the hollow area is connected to the printing groove.

[0013] The area of ​​the linear substructure cross-section is 16 μm. 2 ~225μm 2 The cross section is a plane formed by the first direction and the thickness direction of the screen body.

[0014] In a possible implementation of the first aspect, when the reinforcing part is the finger structure, the finger structure includes a plurality of linear substructures; the plurality of linear substructures are spaced apart in the first direction, and a hollow area is formed between two adjacent linear substructures, the hollow area being in communication with the printing groove;

[0015] In the second direction, each of the linear substructures traverses the printing groove, and each of the linear substructures is disposed between two opposite sides of the printing groove;

[0016] The second direction intersects with the first direction.

[0017] In a possible implementation of the first aspect, the dimension of the printing groove in the second direction is the width; in the first direction, the portion of the printing groove corresponding to the reinforcing portion is constructed as a width-gradient portion, and the spacing between two adjacent linear substructures increases as the width of the width-gradient portion narrows.

[0018] In a possible implementation of the first aspect, the linear substructure satisfies at least one of the following: the diameter of the linear substructure is 3.5 μm to 20 μm; and the spacing D1 between two adjacent linear substructures is 0.042 mm to 0.084 mm.

[0019] In a possible implementation of the first aspect, where the reinforcing part is the honeycomb structure, the honeycomb structure is disposed between two opposite sides of a portion of the printing groove in the second direction; the honeycomb structure includes a plurality of honeycomb grids, the inner peripheral region of each honeycomb grid being a hollow region, the hollow region being connected to the printing groove; wherein the second direction intersects with the first direction.

[0020] In one possible implementation of the first aspect, the screen printing body includes multiple metal sub-layers, which are stacked sequentially in the thickness direction of the screen printing body;

[0021] The plurality of metal sub-layers include a printing shaping layer and a skeleton layer. In the slurry feeding direction of the screen body, the skeleton layer is located behind the printing shaping layer, and the reinforcing part is disposed on the skeleton layer.

[0022] In one possible implementation of the first aspect, in the first direction, the portion of the printing groove that is offset from the reinforcing portion is a first printing portion, and the dimension of the first printing portion in the second direction is the width, and the second direction intersects with the first direction;

[0023] The width of the first printed part in the printed molding layer is W1, and the width of the first printed part in the skeleton layer is W2; wherein, W2∶W1=(13~23)∶1.

[0024] In a possible implementation of the first aspect, the width W1 of the first printed portion in the printed molding layer is 3 μm to 15 μm, and the width W2 of the first printed portion in the skeleton layer is 100 μm to 150 μm.

[0025] In a possible implementation of the first aspect, the portion of the printing groove corresponding to the reinforcing portion is configured as a narrowing portion in the skeleton layer, the width of the narrowing portion being the width in a second direction, and the width of the narrowing portion narrowing along the feeding direction of the screen body; wherein the second direction intersects the first direction.

[0026] In one possible implementation of the first aspect, the plurality of said metal sublayers further include a bonding layer, which connects the skeleton layer and the printing shaping layer in the thickness direction of the screen body.

[0027] In a possible implementation of the first aspect, the printed molding layer satisfies at least one of the following: the material of the printed molding layer is a nickel alloy; the thickness T1 of the printed molding layer is 2μm to 20μm; the skeleton layer satisfies at least one of the following: the material of the skeleton layer is a nickel alloy; the thickness T2 of the skeleton layer is 2μm to 20μm; the bonding layer satisfies at least one of the following: the material of the bonding layer is selected from at least one of nickel or copper; and / or, the thickness T3 of the bonding layer is 70nm to 80nm.

[0028] In a possible implementation of the first aspect, in the first direction, the portion of the printed groove that is offset from the reinforcing portion is configured as a current collector grid line for printing a solar cell; the reinforcing portion satisfies at least one of the following:

[0029] The reinforcing portion includes a first reinforcing portion, which is configured as a first connection structure printed on the current collector line, and the first connection structure is disposed at the intersection of the current collector line and the busbar line.

[0030] The reinforcing portion includes a second reinforcing portion, which is configured as a second connection structure printed on the collector grid line. In the first direction, the second connection structure is offset from the bus grid line and both ends of the second connection structure are connected to the same collector grid line.

[0031] In a possible implementation of the first aspect, when the reinforcing portion includes a first reinforcing portion, the portion of the printing groove corresponding to the first reinforcing portion is a second printing portion; the reinforcing portion satisfies at least one of the following: the length L2 of the second printing portion in the first direction is 0.3 mm to 2 mm;

[0032] The second printing part has a width in the second direction; in the first direction, the width of the second printing part narrows from the middle to both ends, the width W4 at the widest point of the second printing part is 10μm to 100μm, and the width W5 at the narrowest point of the second printing part is 5μm to 60μm;

[0033] When the reinforcing part includes a second reinforcing part, the portion of the printing groove corresponding to the second reinforcing part is a third printing part. The length L3 of the third printing part in the first direction is 0.1 mm to 2 mm, and the width W6 of the third printing part in the second direction is 8 μm to 100 μm.

[0034] Wherein, the first direction intersects with the second direction.

[0035] In a possible implementation of the first aspect, in the first direction, the portion of the printing groove that is offset from the reinforcing portion is a first printing portion, and the opening ratio of the first printing portion is 80% to 100%; the opening ratio of the reinforcing portion is 30% to 70%.

[0036] In a possible implementation of the first aspect, a plurality of the reinforcing portions are disposed corresponding to the same printing groove, and the plurality of the reinforcing portions are spaced apart in the first direction.

[0037] In one possible implementation of the first aspect, in the first direction, the size of the screen body is D2, the spacing between two adjacent reinforcing parts is D3, and D3 / D2 = 1% to 20%.

[0038] In a possible implementation of the first aspect, the printing screen satisfies at least one of the following: in the first direction, the size D2 of the screen body is 166mm to 230mm, and the distance D3 between two adjacent reinforcing parts is 3mm to 50mm;

[0039] Of two adjacent reinforcing portions on the same printing groove, one reinforcing portion is configured such that a printed connecting structure is disposed at the intersection of the current collector line and the current bus line, and the other reinforcing portion is configured such that the printed connecting structure is offset from the current bus line, wherein the connecting structure is either the first connecting structure or the second connecting structure.

[0040] In a possible implementation of the first aspect, the printing screen satisfies at least one of the following: the reinforcing portion is disposed between at least one or both sides in the thickness direction of the screen body;

[0041] There are multiple printing grooves, which are spaced apart in a second direction, and the second direction intersects with the first direction.

[0042] Secondly, embodiments of this application disclose a printing screen, comprising:

[0043] A screen printing plate body, wherein the screen printing plate body is provided with a printing groove extending along a first direction, the printing groove penetrating the thickness direction of the screen printing plate body, the first direction being perpendicular to the thickness direction of the screen printing plate body; the printing groove satisfies at least one of the following:

[0044] In the first direction, the printing groove has a first printing section and a second printing section connected together, the first printing section having an opening ratio of 80% to 100%, and the second printing section having a hollowed-out first reinforcing section; in the second direction, the first reinforcing section is at least partially connected between two opposite sides of the second printing section.

[0045] In the first direction, the printing groove has a first printing section and a third printing section connected together, the first printing section has an opening ratio of 80% to 100%, and the third printing section is provided with a hollowed-out second reinforcing section; in the second direction, the second reinforcing section is at least partially connected between two opposite sides of the third printing section.

[0046] The second direction intersects with the first direction.

[0047] Thirdly, embodiments of this application disclose a method for manufacturing a printing screen as described in the first or second aspect, comprising the following steps:

[0048] Provide a semi-finished screen printing plate having the aforementioned printing groove;

[0049] The reinforcing portion is fabricated on the printing groove.

[0050] Fourthly, embodiments of this application disclose a solar cell, which is obtained by printing using any of the aforementioned printing screens; or, the solar cell is obtained by printing using a printing screen manufactured by the aforementioned method, the solar cell comprising:

[0051] Solar cell preforms;

[0052] A current collector grid line, wherein the current collector grid line is disposed on the surface of the solar cell preform and extends along the first direction, the first direction being perpendicular to the thickness direction of the solar cell preform; and

[0053] The connection structure is disposed on the surface of the solar cell preform and connected to the current collector grid line; in the thickness direction of the solar cell preform, the maximum height of the connection structure is greater than the maximum height of the current collector grid line.

[0054] In a possible implementation of the fourth aspect, the solar cell further includes a busbar extending along a second direction that intersects the first direction; the connection structure satisfies at least one of the following:

[0055] The connection structure includes a first connection structure, which is disposed at the intersection of the current collector grid line and the current collector grid line.

[0056] The connection structure includes a second connection structure. In the first direction, the second connection structure is offset from the busbar and both ends of the second connection structure are connected to the same collector line.

[0057] In a possible implementation of the fourth aspect, when the connection structure includes a first connection structure, the maximum height of the first connection structure is H2, and the maximum height of the collector grid line is H3; wherein, H3 / H2 = 20% to 90%.

[0058] In a possible implementation of the fourth aspect, the solar cell satisfies at least one of the following: the maximum height H2 of the first connection structure is 3.5 μm to 15 μm;

[0059] The maximum height H3 of the collector grid line is 3μm to 10μm.

[0060] In a possible implementation of the fourth aspect, when the connection structure includes a first connection structure, the first connection structure satisfies at least one of the following: the length L4 of the first connection structure in the first direction is 0.5 mm to 2 mm;

[0061] In the first direction, the width of the first connecting structure narrows from the middle to both ends, the width W7 at the widest point of the first connecting structure is 10μm to 100μm, and the width W8 at the narrowest point of the first connecting structure is 5μm to 60μm.

[0062] In a possible implementation of the fourth aspect, when the connection structure includes a second connection structure, the solar cell satisfies at least one of the following: the length L5 of the second connection structure is 0.1 mm to 2 mm;

[0063] The width W9 of the second connection structure in the second direction is 8μm to 100μm;

[0064] The maximum height H4 of the second connecting structure is 2μm to 12μm;

[0065] The width W10 of the collector grid line in the second direction is 5μm to 20μm.

[0066] In a possible implementation of the fourth aspect, there are multiple collector grid lines and multiple bus grid lines, with the multiple bus grid lines spaced apart along the first direction and the multiple collector grid lines spaced apart along the second direction, and each of the collector grid lines intersects with the multiple bus grid lines.

[0067] Each of the collector grid lines is connected to a plurality of the connection structures. The plurality of connection structures connected to the same collector grid line include a plurality of first connection structures and a plurality of second connection structures. Each first connection structure is disposed at the intersection of the collector grid line and each of the bus grid lines. In a first direction, each second connection structure is located between two adjacent bus grid lines and both ends of the second connection structure are connected to the collector grid line.

[0068] Wherein, the first direction is perpendicular to the second direction.

[0069] In a possible implementation of the fourth aspect, the gate line smoothing factor of the collector gate line is smaller than the gate line smoothing factor of the connection structure.

[0070] In a possible implementation of the fourth aspect, the solar cell satisfies at least one of the following: the grid line smoothing factor of the current collector grid is <1; the grid line smoothing factor of the connection structure is 1 to 8.

[0071] In a possible implementation of the fourth aspect, the solar cell preform includes a silicon substrate, a doped layer, and a first functional film, wherein the doped layer and the first functional film are disposed on the surface of the silicon substrate in a direction away from the silicon substrate.

[0072] Both the connection structure and the collector grid line are disposed on the first functional film and penetrate the first functional film to make ohmic contact with the doped layer.

[0073] Fifthly, embodiments of this application disclose a photovoltaic module comprising a plurality of solar cells, wherein any two solar cells are connected in at least one of series and parallel connection, and at least one solar cell is obtained by screen printing as described in the first or second aspect; or, at least one solar cell is obtained by screen printing using a manufacturing method described in the third aspect; or, at least one solar cell is a solar cell as described in the fourth aspect.

[0074] Compared with the prior art, the beneficial effects of this application are:

[0075] The printing screen disclosed in this application features a reinforcing section that corresponds to a portion of the printing groove. This means the reinforcing section structurally strengthens the screen body at a specific location within the printing groove, thereby increasing its structural strength. Furthermore, to ensure printing continuity in the printing groove, the reinforcing section is designed with at least partial open sections that are connected to the printing groove. In other words, the ink can be printed through the reinforcing section to form a connection structure with the current collector lines. This connection structure enables electrical interconnection between the current collector lines and the busbars, facilitating the transfer of current collected by the current collector lines to the busbars and meeting the process and testing requirements for energizing solar cells. Attached Figure Description

[0076] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0077] Figure 1 is a schematic diagram of the structure of a high aperture ratio screen printing plate (the high aperture printing groove is continuous) in the related technology;

[0078] Figure 2 is a schematic diagram of the structure of a high aperture ratio screen printing plate (the high aperture printing groove is discontinuous) in the related technology;

[0079] Figure 3 is a front view of one structure of the printing screen disclosed in this application;

[0080] Figure 4 is a front view of another structure of the printing screen disclosed in this application;

[0081] Figure 5 is a cross-sectional view of one structure of the printing screen disclosed in this application;

[0082] Figure 6 is a cross-sectional view of another structure of the printing screen disclosed in this application;

[0083] Figure 7 is a structural schematic diagram of the reinforcing part disclosed in this application when it is a finger-like structure;

[0084] Figure 8 is a structural schematic diagram of the reinforcing part disclosed in this application when it is a honeycomb structure;

[0085] Figure 9 is a structural schematic diagram of the reinforcing part disclosed in this application when it is a mesh structure;

[0086] Figure 10 is a structural schematic diagram of the reinforcing part disclosed in this application when it is a ring structure;

[0087] Figure 11 is a structural schematic diagram of the reinforcing part disclosed in this application when it is a broken line structure;

[0088] Figure 12 is a schematic diagram of the structure of the printing screen disclosed in this application (when the reinforcing part is a finger structure);

[0089] Figure 13 is a partial enlarged view of region I shown in Figure 12;

[0090] Figure 14 is a cross-sectional view of AA shown in Figure 13;

[0091] Figure 15 is a cross-sectional view of BB shown in Figure 12;

[0092] Figure 16 is a schematic diagram of the printing groove disclosed in this application;

[0093] Figure 17 is a schematic diagram of the structure of the solar cell disclosed in this application;

[0094] Figure 18 is a partial enlarged view of region II shown in Figure 17;

[0095] Figure 19 is a partial enlarged view of region III shown in Figure 17;

[0096] Figure 20 is the CC cross-sectional view shown in Figure 17;

[0097] Figure 21 is a topographical diagram of the collector grid and connection structure disclosed in this application;

[0098] Figure 22 is a cross-sectional profile of the collector grid and connection structure disclosed in this application;

[0099] Figure 23 is a schematic diagram of the structure of the photovoltaic module disclosed in this application.

[0100] Explanation of reference numerals in the attached drawings: 10. Printing screen; 11. Screen body; 111. Printing shaping layer; 112. Skeleton layer; 113. Bonding layer; 12. Reinforcing part; 12a. Finger structure; 12b. Honeycomb structure; 12c. Grid structure; 12d. Ring structure; 12e. Folded line structure; 12f. First reinforcing part; 12g. Second reinforcing part; 121. Linear substructure; 122. Hollowed-out area; 123. Honeycomb grid; 13. Printing groove; 131. First printing section; 132a. Second printing section; 132b. Third printing section; 133. First opening section; 134. Second opening section; 1 35. Width gradient section; 136. Width narrowing section; X, first direction; Y, second direction; Z, thickness direction of the screen body; 20. Solar cell; 21. Solar cell preform; 211. Silicon substrate; 212. Doped layer; 213. First functional film; 214. Interface passivation layer; 215. Second doped polycrystalline silicon layer; 216. Second functional film; 22. Current collector grid line; 23a, 23b. Connection structure; 23a. First connection structure; 23b. Second connection structure; 24. Busbar grid line; 30. High aperture ratio screen; 31. High aperture printing groove; 40. Electrical connector. Detailed Implementation

[0101] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0102] In this application, the terms "upper," "inner," "outer," "front," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] The current collector grid lines of solar cells can be printed using a screen printing machine. Taking a wire mesh screen as an example, the ink paste is printed onto the solar cell preform after passing through the printing grooves on the screen. The pattern of these printing grooves matches the pattern of the current collector grid lines, thus creating a patterned ink paste. The current collector grid lines are then obtained after the ink paste is sintered. However, the wires on the screen can obstruct the ink flow, affecting the flatness of the current collector grid lines. Especially when the linewidth of the current collector grid lines is narrow, screen printing can easily lead to printing defects such as broken grids and indistinct printing. However, narrower linewidth current collector grid lines can reduce the wet weight of the ink paste and decrease the shading area, which is beneficial for cost reduction and efficiency improvement in solar cells. In other words, it is difficult to achieve cost reduction and efficiency improvement by narrowing the linewidth of current collector grid lines printed using a wire mesh screen.

[0107] As shown in Figure 1, the high aperture ratio screen 30 can avoid the problems associated with the aforementioned wire mesh screens. In some embodiments, the high aperture screen is mainly achieved by directly setting a high aperture printing groove 31 on a metal / alloy screen. This printing groove, without the obstruction of steel wire, allows for better ink flow, enabling the printing of narrower linewidth collector lines while reducing the frequency of printing defects. However, the inventors have found that because metal screens are typically thin, and the high aperture printing groove 31 usually extends to a certain length, the strength of the high aperture ratio screen 30 at the corresponding position of the high aperture printing groove 31 weakens. In particular, the longer the high aperture printing groove 31, the worse the structural strength of the high aperture ratio screen 30. However, to print continuous collector lines, the high aperture printing groove 31 must be continuous and relatively long, resulting in poor structural strength of the high aperture ratio screen 30.

[0108] It should be noted that in this application, "high opening ratio" refers to an opening ratio of 80% to 100%.

[0109] The inventors discovered, as shown in Figure 2, that by staggering the high-aperture printing groove 31 into multiple segments (i.e., making the high-aperture printing groove 31 discontinuous), the length of the high-aperture printing groove 31 can be shortened, thus reducing its impact on the structural strength of the high-aperture screen 30. However, the current collector grid lines printed by this discontinuous high-aperture printing groove 31 are also staggered into multiple segments. Connecting structures located at the staggered positions of the current collector grid lines need to be printed in other printing processes to connect the staggered current collector grid lines into a continuous structure. In other words, continuous current collector grid lines cannot be printed in a single printing process. Furthermore, when the solar cell front side is printed twice, this connecting structure, due to the use of a non-burn-through paste, does not form ohmic contact with the doped layer. This means the connecting structure lacks the function of collecting charge carriers from the crystalline silicon substrate or doped layer, resulting in a decrease in the overall current collection efficiency of the current collector grid lines. Moreover, when this connecting structure experiences printing misalignment due to equipment alignment issues, it is prone to forming ineffective electrical connections with the discontinuous current collector grid lines, affecting current transmission.

[0110] Based on the above analysis, this application provides a printing screen whose printing grooves can be used to print current collector lines. Considering that excessively long printing grooves can affect the structural strength of the screen body, a reinforcing portion is provided corresponding to a portion of the printing groove. In other words, the reinforcing portion structurally strengthens a portion of the printing groove to reduce its impact on the structural strength of the screen body. To maintain the printing continuity of the printing grooves, at least a portion of the reinforcing portion is hollowed out. In other words, the paste can be printed through the reinforcing portion to form a connection structure to the current collector lines. This connection structure maintains the continuity of the current collector lines, which is beneficial for current collection and meets the process and testing requirements for energizing solar cells.

[0111] The technical solution of the present invention will now be described in conjunction with the embodiments and accompanying drawings.

[0112] In the first aspect, referring to Figures 3 to 5, this application discloses a printing screen 10, including a screen body 11 and a reinforcing part 12.

[0113] The screen body 11 is provided with a printing groove 13 extending along the first direction X. The printing groove 13 penetrates the screen body 11 along the thickness direction Z. The first direction X is perpendicular to the thickness direction of the screen body 11.

[0114] At least a portion of the reinforcing part 12 is disposed at the position where the printing groove 13 is provided on the screen body 11. The reinforcing part 12 is partially disposed corresponding to the printing groove 13. At least a portion of the reinforcing part 12 is hollowed out, and the hollowed-out part of the reinforcing part 12 is connected to the printing groove 13.

[0115] It should be noted that the extension of the printing groove 13 along the first direction X can be understood as the printing groove 13 extending along the first direction X, that is, the first direction X is the length direction of the printing groove 13.

[0116] The printing groove 13 of the printing screen 10 can be used to print current collector lines. Considering that an excessively long printing groove 13 would affect the structural strength of the screen body 11, the reinforcing part 12 of this application is partially provided corresponding to the printing groove 13. That is, the reinforcing part 12 structurally reinforces the screen body 11 at a portion of the printing groove 13 to reduce the impact of the printing groove 13 on the structural strength of the screen body 11. To maintain the printing continuity of the printing groove 13, the reinforcing part 12 of this application is at least partially hollowed out. In other words, the paste can be printed through the reinforcing part 12 to form a connection structure connected to the current collector lines. This connection structure maintains the continuity of the current collector lines, which is beneficial for current collection by the current collector lines and can meet the process and testing requirements for energizing solar cells.

[0117] In summary, the printing screen 10 combines the advantages of high printing quality and high structural strength, and can print continuous collector grid lines, which is beneficial for current collection by the collector grid lines and can meet the process and testing requirements for energizing solar cells.

[0118] More specifically, paste refers to the paste used for printing solar cell grid lines, such as silver paste or silver-aluminum paste, aluminum paste, copper paste or silver-coated copper paste.

[0119] In this embodiment, there are multiple printing slots 13, which are spaced apart in the second direction Y. Specifically, the number of printing slots 13 can be two, three, four, etc., and this embodiment does not limit this. The multiple printing slots 13 are used to print multiple collector grid lines spaced apart in the second direction Y.

[0120] It should be noted that when there are multiple printing slots 13, the presence of a reinforcing part 12 on at least one printing slot 13 can structurally reinforce the screen body 11. Of course, as shown in Figure 3, this application can also provide reinforcing parts 12 on multiple printing slots 13. Furthermore, as shown in Figure 4, this application can also use one reinforcing part 12 corresponding to multiple printing slots 13. For example, along the second direction, the reinforcing part 12 can extend from one side of the screen body 11 to the other side, thus allowing the reinforcing part 12 to pass through the multiple printing slots 13 and achieve structural reinforcement of the screen body 11.

[0121] The printing groove and the reinforcing part are described in detail below.

[0122] It is understood that the printing groove can be formed on the screen body by means of laser etching, chemical etching, electroplating, etc. That is, the printing groove has a high opening design on the screen body. Along the thickness direction of the screen body, the printing groove runs through both sides of the screen body along the thickness direction, so that the printing groove forms an opening on both sides of the screen body in the thickness direction.

[0123] Considering that the reinforcing part is mainly for enhancing the structural strength of the screen body at the position corresponding to the printing groove, as shown in Figures 3 and 4, in this embodiment of the application, the printing groove 13 has a first opening segment 133 and a second opening segment 134 in the first direction X, and the reinforcing part 12 is located between the first opening segment 133 and the second opening segment 134. It can be understood that the reinforcing part 12 strengthens the area between the first opening segment 133 and the second opening segment 134, which is equivalent to the reinforcing part 12 structurally strengthening the screen body 11 at the middle position of both ends of the printing groove 13, resulting in a better strengthening effect.

[0124] In some embodiments, referring to Figures 5 and 6, a reinforcing portion 12 is disposed between two opposite sides of the printing groove 13 in the second direction Y. The second direction Y intersects the first direction X.

[0125] The reason for the decreased structural strength of the screen body 11 is the lack of tension between the two opposite sides of the printing groove 13. Therefore, providing a reinforcing part 12 between the two opposite sides of part of the printing groove 13 can effectively enhance the structural strength of the screen body 11. For example, the reinforcing part 12 is integrally formed between the two opposite sides of the printing groove 13. The integral forming method makes the integrity between the reinforcing part 12 and the screen body 11 better, thereby effectively enhancing the structural strength of the screen body 11.

[0126] More specifically, the reinforcing part 12 can be integrally formed, for example, by electroforming, laser engraving, or electroplating. Of course, the reinforcing part 12 can also be provided by non-integral forming fixing methods such as bonding, welding, or lamination.

[0127] In embodiments of this application, the second direction Y can be perpendicular to the first direction X. This perpendicularity includes complete perpendicularity, i.e., the angle between the first direction X and the second direction Y is 90°. It also includes approximately perpendicularity, for example, the angle between the first direction X and the second direction Y is 87°, 88°, 89°, 91°, or 92°. Of course, in other embodiments, the first direction X and the second direction Y may not be perpendicular, for example, they may be at other angles such as 85° or 95°.

[0128] Referring to Figures 5 and 6, in some specific embodiments, the reinforcing portion 12 is disposed between at least one or both sides of the screen body 11 in the thickness direction Z. The fact that the reinforcing portion 12 is fixedly disposed on at least one side of the screen body 11 in the thickness direction Z can be understood as: the reinforcing portion 12 is fixedly disposed on one or both sides of the screen body 11 in the thickness direction Z. For example, in Figure 5, when the reinforcing portion 12 is fixedly disposed on one side of the screen body 11 in the thickness direction Z, this reinforcing portion 12 helps to expand the ink dispensing space of the printing tank 13 and increase the molding space of the ink, allowing for the printing of higher grid lines. Alternatively, referring to Figure 6, when the reinforcing portion 12 is fixedly disposed between both sides of the screen body 11 in the thickness direction Z, the reinforcing portion 12 at this position is equivalent to reinforcing the screen body 11 internally, which is more conducive to reducing the impact of the printing tank arrangement on the structural strength of the screen body 11.

[0129] In some embodiments, as shown in Figures 7 to 11, the reinforcing portion 12 may include at least one of a finger structure 12a, a honeycomb structure 12b, a mesh structure 12c, a ring structure 12d, or a polygonal structure 12e. The inclusion of at least one of the finger structure 12a, honeycomb structure 12b, mesh structure 12c, ring structure 12d, or polygonal structure 12e in the reinforcing portion 12 can be understood as any combination of one or more of the following: finger structure 12a, honeycomb structure 12b, mesh structure 12c, ring structure 12d, or polygonal structure 12e.

[0130] These structures can provide stronger mechanical structural support for the screen printing plate, and all of these structures can form a hollow area 122, so that the printing groove 13 directly below the projection of the hollow area 122 and the hollow area 122 form a deeper ink application area, thereby forming a connection structure with a higher printing height.

[0131] Furthermore, the reinforcing part has multiple linear substructures 121, which are spaced apart to form a hollow area 122;

[0132] Alternatively, multiple linear substructures 121 can be connected to form a cutout area 122, which communicates with the printing groove 13. The reinforcing section composed of linear substructures 121 has sufficient structural strength to reinforce the screen body, and can also form a deeper ink application zone in the area corresponding to the printing groove 13 and the reinforcing section 12, which is beneficial for forming a connection structure with a higher printing height. For example, the linear substructure 121 can be a metal wire such as steel wire.

[0133] Of course, the reinforcing part can also be a thin film structure, for example, multiple perforations can be formed on the thin film structure.

[0134] More specifically, as shown in Figure 7, when the reinforcing part is a finger-like structure 12a, multiple linear substructures 121 are spaced apart to form a hollow area 122. As shown in Figure 8, when the reinforcing part is a honeycomb structure 12b, multiple linear substructures 121 are connected to form a hollow area 122.

[0135] As shown in Figure 9, when the reinforcing part is a mesh structure 12c, multiple linear substructures 121 are connected and interwoven to form a hollow area 122. As shown in Figure 10, when the reinforcing part is a ring structure 12d, the linear substructures 121 are annular, such as circular rings, elliptical rings, or polygonal rings. In this case, hollow areas 122 are formed on the inner circumference of the linear substructures 121 and between two linear substructures 121. As shown in Figure 11, when the reinforcing part is a broken line structure 12e, multiple linear substructures 121 are connected end to end in sequence to form a hollow area 122. Of course, the above are only examples of some reinforcing parts, and the embodiments of this application are not limited to these.

[0136] In other embodiments, the cross-sectional area of ​​the linear substructure 121 is 16 μm. 2 ~225μm 2 And the value at any point within that area, for example, 16 μm. 2 50μm 2 100μm 2 150μm 2 or 225μm 2 The cross-section is a plane formed by the first direction X and the thickness direction Z of the screen body 11. When the cross-section of the linear substructure 121 meets this area range, it can effectively enhance the structural strength of the screen body 11, reduce the obstruction of the slurry, and make the slurry pass through the reinforcing part 12 better.

[0137] In some embodiments, specifically as shown in FIG8, when the reinforcing part 12 is a honeycomb structure 12b, the honeycomb structure 12b may be disposed between two opposite sides of a portion of the printing groove 13 in the second direction Y. The honeycomb structure 12b includes a plurality of honeycomb grids 123, and the inner peripheral region of each honeycomb grid 123 is formed as a hollow region 122, which is connected to the printing groove 13.

[0138] The honeycomb structure 12b provides good structural reinforcement to the printing groove 13 because it has good geometric and mechanical properties. Furthermore, the hollow areas 122 on the inner periphery of the honeycomb grid 123 allow for ink application, thus enabling the honeycomb structure 12b to simultaneously achieve structural reinforcement and ink application.

[0139] The following section provides a further detailed explanation of the reinforcing part, using the example of a finger-like structure.

[0140] Referring to Figures 12 and 13, in some embodiments, when the reinforcing part 12 is a finger-like structure 12a, the finger-like structure 12a includes a plurality of linear substructures 121. The plurality of linear substructures 121 are spaced apart in the first direction X, and a hollow region 122 is formed between two adjacent linear substructures 121, which communicates with the printing groove 13. In the second direction Y, each linear substructure 121 traverses the printing groove 13, and each linear substructure 121 is disposed between two opposite sides of the printing groove 13.

[0141] It should be noted that the number of linear substructures 121 in each finger structure 12a can be two, three or four, and this application embodiment does not limit this.

[0142] Further, as shown in Figure 13, the dimension of the printing groove 13 in the second direction Y is its width. In the first direction X, the portion of the printing groove 13 corresponding to the reinforcing portion 12 is constructed as a width gradient portion 135, which refers to the portion of the printing groove 13 where the width gradually narrows or widens. The width gradient portion 135 can be used to print a connection structure with a width gradient, so that the connection structure forms an electrical interconnection area between the narrower collector grid line and the bus grid line through the width gradient, while taking into account low silver consumption and good soldering performance. Considering that the strength of the screen body is weaker at the position where the width of the width gradient portion 135 is larger, and the ink passage is worse at the position where the width of the width gradient portion 135 is narrower, based on this, in this embodiment, the spacing between two adjacent linear substructures 121 increases as the width of the width gradient portion 135 narrows. In other words, where the width of the gradient section 135 is relatively large, the spacing between two adjacent linear substructures 121 is also relatively small, thereby increasing the structural strength at that location by narrowing the spacing of the linear substructures 121. Conversely, where the width of the gradient section 135 is relatively narrow, the spacing between two adjacent linear substructures 121 is also relatively large. This is because the structural strength of the screen body corresponding to the narrower width of the gradient section 135 is relatively high. On the one hand, there is no need to increase the distribution density of the linear substructures 121 to improve the structural strength at that location. On the other hand, by flexibly setting the distribution density of the linear substructures 121, which is negatively correlated with the width of the gradient section 135, the ink application rate between the wider and narrower sections of the gradient section 135 can be balanced, thereby reducing ink consumption while meeting current transmission requirements.

[0143] As shown in Figure 13, in some embodiments, the spacing D1 between two adjacent linear substructures 121 is 0.042 mm to 0.084 mm, which can include any value within this spacing range, such as 0.042 mm, 0.06 mm, or 0.084 mm. When the spacing D1 between two adjacent linear substructures 121 meets the above range, the linear substructures 121 are distributed sufficiently densely, the structural reinforcement effect of the finger structure 12a is better, and there is sufficient space between the two linear substructures 121 for the paste to pass through, reducing the impact of the linear substructures 121 on the printing effect.

[0144] Optionally, the linear substructure is at least partially arched in the thickness direction of the screen body. Of course, the linear substructure can also be straight.

[0145] In some embodiments, the line diameter of the linear substructure 121 in the finger structure 12a is 6μm to 15μm and any value within this range, such as 6μm, 7μm, 10μm, or 15μm. When the linear substructure 121 meets the above-mentioned line diameter range, the structural strength of the finger structure 12a is high, which provides a strong mechanical reinforcement effect on the screen body 11. Furthermore, the linear substructure 121 is also sufficiently fine to reduce the amount of ink applied, thereby achieving the effect of reducing ink consumption while meeting the requirements of grid line printing.

[0146] The following is a detailed explanation of the main body of the web version.

[0147] It should be noted that although the following explanation is based on an example where the reinforcement is a finger-like structure, it is understood that the following explanation of the screen body also applies to various cases where the reinforcement is a honeycomb structure, grid structure, ring structure, or polygonal structure.

[0148] In other embodiments, the screen body may be made of, for example, metal or alloy. As shown in Figures 14 and 15, in this embodiment, the screen body 11 includes multiple metal sublayers, which are stacked sequentially in the thickness direction Z of the screen body 11.

[0149] It is understandable that each metal sublayer is thinner than the main screen 11, thus each metal sublayer has the advantage of high grooving precision. Precise grooving can be performed on the metal sublayers to obtain partial printing grooves 13. After the metal sublayers are stacked, a high-precision printing groove 13 is obtained. Furthermore, the total thickness of the main screen 11 obtained after stacking the metal sublayers is also relatively thick, resulting in a larger grid line printing height. Since the depth of the printing grooves 13 is comparable to the thickness of the main screen 11, the thicker main screen 11 also facilitates the shaping of the printing grid lines, thereby printing sufficiently high current collector lines and connection structures.

[0150] The material of the aforementioned metal sublayer can be selected from one or more of iron, aluminum, titanium, copper, nickel or chromium; of course, the material of the metal sublayer can also be other metal materials; the number of the aforementioned metal sublayer can be two, three or four layers; of course, the number of metal sublayers can also be other, which is not limited in this application.

[0151] Furthermore, the multiple metal sublayers include a printing shaping layer 111 and a skeleton layer 112. In the ink feeding direction of the screen body 11, the skeleton layer 112 is located behind the printing shaping layer 111. A reinforcing portion 12 is disposed on the skeleton layer 112. The term "ink feeding direction" refers to the direction in which the ink is transported within the screen body 11. It can be understood that, since the skeleton layer 112 is located above the printing shaping layer 111, the ink, after entering the screen body 11, first passes through the skeleton layer 112 and then enters the printing shaping layer 111. Disposing of the reinforcing portion 12 on the skeleton layer 112 reduces the influence of the reinforcing portion 12 on ink shaping, thereby improving printing quality. Furthermore, the reinforcing portion 12 located in the skeleton layer 112 can prevent the slurry in the skeleton layer 112 from being scraped away when the slurry is applied by the squeegee, thus retaining as much slurry as possible in the skeleton layer 112. This allows the slurry in the skeleton layer 112 and the slurry in the printed shaping layer 111 to be cumulatively printed onto the surface of the solar cell preform. Generally speaking, the height of the slurry printed in the reinforcing portion 12 is approximately the same as the sum of the thicknesses of the skeleton layer 112 and the printed shaping layer 111. It should be noted that the statement that the height of the slurry printed in the reinforcing portion 12 is approximately the same as the sum of the thicknesses of the skeleton layer 112 and the printed shaping layer 111 can be interpreted as: the height of the slurry printed in the reinforcing portion 12 is the same as the sum of the thicknesses of the skeleton layer 112 and the printed shaping layer 111; or, the height of the slurry printed in the reinforcing portion 12 deviates slightly from the sum of the thicknesses of the skeleton layer 112 and the printed shaping layer 111.

[0152] In other embodiments, the reinforcing part 12 integrally formed with the skeleton layer 112 is also made of metal. The metal reinforcing part 12 has good ductility and toughness, and can strengthen the structure of the screen body 11 during long-term use, which is beneficial to improving the service life of the screen body 11.

[0153] More specifically, in Figure 14, the dimension of the reinforcing part 12 in the thickness direction Z of the screen body 11 can be the same as or different from the thickness of the skeleton layer 112. The reinforcing part 12 can be disposed at any position in the thickness direction of the skeleton layer 112.

[0154] In this embodiment, the printing shaping layer 111 is made of a nickel alloy, such as nickel steel. The nickel alloy printing shaping layer 111 possesses excellent corrosion resistance and mechanical properties, such as good ductility and toughness, making it suitable for the application scenarios of the printing screen 10. Of course, the printing shaping layer 111 can also be made of other metals.

[0155] In other embodiments, the thickness T1 of the printed shaping layer 111 is 2μm to 20μm and any value within this thickness range, such as 2μm, 5μm, 10μm, 15μm, or 20μm. When the printed shaping layer 111 meets the above thickness range, the printed shaping layer 111 has a good paste shaping effect, high grooving accuracy, and a high printed grid line height.

[0156] In this embodiment, the skeleton layer 112 is made of a nickel alloy, such as nickel steel. The nickel alloy skeleton layer 112 possesses excellent corrosion resistance and mechanical properties, such as good ductility and toughness, making it suitable for the application scenarios of the printing screen 10. Of course, the skeleton layer 112 can also be made of other metals.

[0157] In other embodiments, the thickness T2 of the skeleton layer 112 is 2μm to 20μm and any value within this thickness range, such as 2μm, 5μm, 10μm, 15μm, or 20μm. When the skeleton layer 112 meets the above thickness range, the skeleton layer 112 has good structural strength, high slotting accuracy, and high printed grid line height.

[0158] Furthermore, the multiple metal sublayers also include a bonding layer 113, which connects the skeleton layer 112 and the printing shaping layer 111 in the thickness direction Z of the screen body 11. The bonding layer 113 is used to enhance the bonding force between the skeleton layer 112 and the printing shaping layer 111, thereby improving the overall strength of the screen body 11.

[0159] In some embodiments, the bonding layer 113 is made of at least one of nickel or copper. Both nickel and copper are metals that can be used to enhance the adhesion of nickel alloy films, and the skeleton layer 112 and the printed molding layer 111 are made of nickel alloy. The bonding layer 113 made of at least one of nickel or copper can effectively enhance the bonding force between the skeleton layer 112 and the printed molding layer 111, resulting in a better bonding effect between the skeleton layer 112 and the printed molding layer 111.

[0160] In other embodiments, the thickness T3 of the bonding layer 113 is 70 nm to 80 nm and any value within this thickness range, such as 70 nm, 75 nm, or 80 nm. When the bonding layer 113 meets the above thickness range, the bonding layer 113 can effectively enhance the connection strength between the skeleton layer 112 and the printed molding layer 111.

[0161] The printing groove is described in detail below.

[0162] It should be noted that although the following description is based on an example where the reinforcement is a finger-like structure, it is understood that the following description of the printing groove also applies to various cases where the reinforcement is a honeycomb structure, grid structure, ring structure, or zigzag structure.

[0163] In some embodiments, referring to FIG12, in the first direction X, the portion of the printing groove 13 that is offset from the reinforcing portion 12 is the first printing portion 131. The opening ratio of the first printing portion 131 is 80% to 100% and any value within the range of the opening ratio, such as 80%, 90% or 100%, more preferably 100%, that is, the first printing portion 131 has a high opening. Since there are no objects such as steel wires blocking the first printing portion 131 with a high opening, it has better paste passage and can print narrower line width current collector lines while printing fewer anomalies.

[0164] When the first printing section 131 has a 100% full aperture ratio, there are no steel wires at the first printing section 131 to reinforce the mechanical support strength of the printing screen 10. When the first printing section 131 has a high aperture ratio of 80% to 100% (excluding the 100% endpoints), sparsely distributed steel wires are used at the first printing section 131 to reinforce the mechanical support strength of the printing screen 10. Compared to the aforementioned first printing section 131 with a 100% aperture ratio, although the sparsely distributed steel wires may obstruct the downward flow of ink and increase the unevenness of the grid lines printed by the first printing section 131, the impact is smaller due to the sparse distribution of the steel wires. Moreover, the mechanical support strength of the printing screen 10 can be increased by using the sparsely distributed steel wires. Therefore, by using a screen with sparsely distributed steel wires at the first printing section 131, the smoothness factor of the printed first connection structure is smaller.

[0165] On the other hand, the opening ratio of the reinforcing part 12 is 30% to 70%. When the reinforcing part 12 meets this opening ratio range, it indicates that the reinforcing part 12 can provide a mechanical support part of a suitable area for the printing screen 10, thereby effectively enhancing the structural strength of the screen body 11. At the same time, it also indicates that the reinforcing part 12 has a large number of hollow areas 122, and the paste has good passage in the reinforcing part 12, which is conducive to the penetration of the paste and printing on the surface of the solar cell.

[0166] In some embodiments, continuing to refer to FIG12, a plurality of reinforcing portions 12 are provided corresponding to the same printing groove 13, and the plurality of reinforcing portions 12 are spaced apart in the first direction X. Since the printing groove 13 needs to be relatively long in the first direction X in order to print continuous and sufficiently long collector lines, the length of the printing groove 13 also needs to be relatively long. By providing a plurality of reinforcing portions 12, that is, by providing a reinforcing portion 12 at regular intervals in the printing groove 13 to strengthen the structural strength of the screen body 11, the overall structural strength of the screen body 11 is high, and the length of the printing groove 13 can be extended as much as possible to print sufficiently long collector lines.

[0167] In some embodiments, in the first direction X, the size of the screen body 11 is D2, and the distance between two adjacent reinforcing parts 12 is D3, where D3 / D2 = 1% to 20% and includes any value within this range, such as 1%, 5%, 10%, 15%, or 20%. When the printing screen 10 meets the above-mentioned ratio range, the distribution density of the reinforcing parts 12 on the screen body 11 is moderate, providing sufficient density reinforcement. This ensures that the screen body 11 has high overall structural strength, and at the same time, since the number of positions of the printing groove 13 blocked by the reinforcing parts 12 is small, it is beneficial for the feeding of ink into the printing groove 13 and for printing. The distance D3 between two adjacent reinforcing parts 12 refers to the distance between the centers of two adjacent reinforcing parts 12.

[0168] In other embodiments, in the first direction X, the size D2 of the screen body 11 is 166mm to 230mm and any value within this range, such as 166mm, 182mm, 210mm, or 230mm. The distance D3 between two adjacent reinforcing parts 12 is 3mm to 50mm and any value within this range, such as 3mm, 10mm, 20mm, or 50mm. When the size D2 of the screen body 11 and the distance D3 between two adjacent reinforcing parts 12 satisfy the above ranges, the distribution density of the reinforcing parts 12 is moderate, the structural strength of the screen body 11 is high, and the number of positions where the printing groove 13 is blocked by the reinforcing parts 12 is small, which is beneficial to the feeding of ink into the printing groove 13 and printing.

[0169] In other embodiments, of two adjacent reinforcing portions 12 on the same printing groove 13, one reinforcing portion 12 is configured such that the printed connecting structure is located at the intersection of the current collector line and the busbar line, while the other reinforcing portion 12 is configured such that the printed connecting structure is offset from the busbar line. Examples of the positions of these reinforcing portions will be given below.

[0170] Please refer to Figures 12 to 15. The dimension of the first printed portion 131 in the second direction Y is its width.

[0171] Specifically, as shown in Figure 15, the width of the first printing section 131 in the printing shaping layer 111 is W1, and the width of the first printing section 131 in the skeleton layer 112 is W2; wherein, W2∶W1=(13~23)∶1, which includes any value within this ratio range, such as 13∶1, 15∶1, 20∶1, or 23∶1. When W2∶W1 satisfies the above ratio range, the squeegee can extend into the portion of the first printing section 131 in the skeleton layer 112 under stress deformation, thereby scraping away the paste of the first printing section 131 in the skeleton layer 112. At the same time, since the ratio of W2∶W1 is large enough, it can provide sufficient paste source for the paste in the printing shaping layer 111, improving the penetration of the paste in the printing shaping layer 111.

[0172] It should be noted that the fact that the height of the paste printed by the first printing section 131 is approximately the same as the thickness of the printed molding layer 111 can be interpreted as: the height of the paste printed by the first printing section 131 is the same as the thickness of the printed molding layer 111, or the height of the paste printed by the first printing section 131 deviates slightly from the thickness of the printed molding layer 111.

[0173] Based on the above analysis, the height of the slurry printed on the reinforcing part 12 is approximately the same as the sum of the thicknesses of the skeleton layer 112 and the printed shaping layer 111.

[0174] The height of the paste printed in the first printing section 131 is the same as the thickness of the printed molding layer 111. In this application, the first printing section 131 is configured to print the current collector lines of a solar cell. The reinforcing section 12 is configured to print the connection structure connected to the current collector lines. Therefore, it can be understood that the printing screen of this application, through a single printing process, can produce a connection structure with a maximum height greater than the current collector lines.

[0175] In some embodiments, the width W1 of the first printed portion 131 in the printed molding layer 111 is 3μm to 15μm and any value within this width range, such as 3μm, 5μm, 10μm, or 15μm. When the width W1 of the first printed portion 131 in the printed molding layer 111 meets the above-mentioned width range, it can be used to print narrower linewidth collector grids to reduce costs and increase efficiency, and it can also have a lower light shading rate to improve the conversion efficiency of solar cells.

[0176] It is understandable that if the width W2 of the first printed portion 131 in the skeleton layer 112 is less than 100μm, the paste of the first printed portion 131 in the skeleton layer 112 will easily accumulate on the paste in the printed molding layer 111. In this case, the height of the current collector grid line printed from the first printed portion 131 is equivalent to the sum of the thicknesses of the skeleton layer 112 and the printed molding layer 111, resulting in an increased wet weight of the current collector grid line paste. At the same time, it will also cause the printed grid line to be too wide, thereby increasing the obstruction of incident light and hindering the improvement of the solar cell's utilization rate of incident light. If the width W2 of the first printed portion 131 in the skeleton layer 112 is greater than 150μm, the first printed portion 131 will create an excessively large opening in the skeleton layer 112, resulting in a decrease in the structural strength of the skeleton layer 112. In some other embodiments, the width W2 of the first printed portion 131 in the skeleton layer 112 is 100μm to 150μm and includes any point value within this width range, such as 100μm, 120μm, 140μm or 150μm.

[0177] When the width W2 of the first printing section 131 in the skeleton layer 112 meets the aforementioned width range, the structural strength of the skeleton layer 112 is high. Furthermore, when the difference between width W2 and width W1 is sufficiently large, less paste from the first printing section 131 accumulates on the paste in the printing molding layer 111, so that the height of the current collector lines printed by the first printing section 131 is mainly determined by the thickness of the printing molding layer 111. This allows for the printing of current collector lines with lower heights, thereby reducing the wet weight of the paste during current collector line printing.

[0178] Furthermore, as shown in Figures 12 and 14, the portion of the printing groove 13 and the reinforcing portion 12 that is disposed in the skeleton layer 112 is constructed as a width-narrowing portion 136. The width-narrowing portion 136 has a width in the second direction, and the width of the width-narrowing portion 136 narrows along the feeding direction of the screen body 11.

[0179] In other words, the narrowing section 136 utilizes a wider portion for paste feeding to improve paste throughput. The narrowing section 136 narrows along the paste feeding direction of the screen body 11, resulting in a higher paste compaction density along the feeding direction. This facilitates the expulsion of air from the paste under the printing pressure of the squeegee, thereby increasing the paste compaction density printed onto the battery cell, reducing the probability of air bubbles mixed in the paste bursting during sintering, and improving the smoothness of the grid lines prepared after paste sintering.

[0180] As described above, in the first direction X, the portion of the printed groove 13 that is offset from the reinforcing portion 12 is configured as the current collector grid line of the printed solar cell, that is, the first printed portion 131 is configured as the current collector grid line of the printed solar cell.

[0181] The reinforcing part 12 includes a first reinforcing part 12f, which is configured as a first connection structure printed on the collector grid line. The first connection structure is disposed at the intersection of the collector grid line and the bus grid line.

[0182] The reinforcing part 12 includes a second reinforcing part 12g, which is configured as a second connection structure printed on the collector grid line. In the first direction X, the second connection structure is offset from the collector grid line and both ends of the second connection structure are connected to the same collector grid line.

[0183] More specifically, there may be one or more reinforcing parts 12. When there is only one reinforcing part 12, it may be either a first reinforcing part 12f or a second reinforcing part 12g. When there are multiple reinforcing parts 12, all of them may be the first reinforcing part 12f; or, all of them may be the second reinforcing part 12g; or, the multiple reinforcing parts 12 may include both the first reinforcing part 12f and the second reinforcing part 12g.

[0184] It should be noted that the first connecting structure is also called an overlapping structure, or a "centipede-leg grid line" or "centipede leg". The second connecting structure is also called a connecting grid line. In this field, both the overlapping structure and the connecting grid line can be wider than the current collector grid line. Correspondingly, in the first direction X, the portion of the printing groove 13 corresponding to the first reinforcing part 12f and the second reinforcing part 12g can be wider than the first printing part 131 described above. Since the first reinforcing part 12f and the second reinforcing part 12g may obstruct the flow of ink, and the first reinforcing part 12f and the second reinforcing part 12g precisely utilize the wider portion of the printing groove 13 for ink application, the ink flow at this location is also better. Through the above design, the influence of the first reinforcing part 12f and the second reinforcing part 12g on the ink flow can be reduced, and the printing quality is also better.

[0185] The length and width of the printing groove corresponding to the first and second reinforcing parts are described in detail below.

[0186] As shown in Figures 12 and 16, when the reinforcing part 12 includes the first reinforcing part 12f, the portion of the printing groove 13 corresponding to the first reinforcing part 12f is the second printing part 132a. The length and width of the second printing part 132a are as follows:

[0187] Considering that if the length L2 of the second printing section 132a in the first direction X is less than 0.3 mm, the length of the first connecting structure printed by the second printing section 132a is insufficient, resulting in poor welding performance, and the length of the first reinforcing section 12f in the first direction X is also small, leading to a decrease in the service life of the printing screen 10. If the length L2 of the second printing section 132a in the first direction X is greater than 2 mm, the area of ​​the first connecting structure printed by the second printing section 132a is large, resulting in a decrease in the efficiency of the solar cell. Based on this, in the embodiments of this application, the length L2 of the second printing section 132a in the first direction X is 0.3 mm to 2 mm and includes any value within this length range, such as 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, or 2 mm. When the second printing section 132a meets the above-mentioned length range, the requirements for welding alignment accuracy can be reduced, thereby improving the welding yield; moreover, the first reinforcing section 12f is also longer in the first direction X, which is beneficial to improving the service life of the printing screen 10.

[0188] The second printing section 132a has a width in the second direction Y. In the first direction X, the width of the second printing section 132a narrows from the middle to both ends. Considering that if the width W4 at the widest point of the second printing section 132a is less than 10 μm, the first connecting structure printed by the second printing section 132a will be narrow, resulting in decreased welding performance, and the size of the first reinforcing part 12f will also be small, leading to a decrease in the service life of the printing screen 10. If the width W4 at the widest point of the second printing section 132a is greater than 100 μm, the first connecting structure printed by the second printing section 132a will be too wide, increasing the light-blocking area. Based on this, in the embodiments of this application, the width W4 of the widest part of the second printing part 132a is 10μm to 100μm and includes any point value within this width range, such as 10μm, 50μm or 100μm. When the widest part of the second printing part 132a meets the above-mentioned width range, the first connection structure printed by the second printing part 132a can provide a higher welding area for welding, thereby improving the pull-out force of the solder strip; moreover, the size of the first reinforcing part 12f is also larger, which is beneficial to improving the service life of the printing screen 10.

[0189] Considering that if the width W5 of the narrowest point of the second printing section 132a is less than 5μm, the ink flow of the second printing section 132a will be poor, and the size of the first reinforcing part 12f will also be reduced accordingly, resulting in a decrease in the lifespan of the printing screen 10; if the width W5 of the narrowest point of the second printing section 132a is greater than 60μm, the first connecting structure printed by the second printing section 132a will be wider, and the light-blocking area will be larger. Based on this, in this embodiment, the width W5 of the narrowest point of the second printing section 132a is 5μm to 60μm and includes any value within this width range, such as 5μm, 30μm, or 60μm. When the narrowest point of the second printing section 132a meets the above width range, the second printing section 132a has better ink flow, and the size of the first reinforcing part 12f is larger, which is beneficial to improving the lifespan of the printing screen 10.

[0190] As shown in Figure 16, when the reinforcing part 12 includes the second reinforcing part 12g, the portion of the printing groove 13 corresponding to the second reinforcing part 12g is the third printing part 132b. The length and width of the third printing part 132b are as follows:

[0191] Considering that if the length L3 of the third printed portion 132b is less than 0.1 mm, the size of the second reinforcing portion 12g will also be small, leading to a decrease in the lifespan of the printing screen 10. If the length L3 of the third printed portion 132b is greater than 2 mm, the printed second connection structure will be too long, reducing the area where the collector grid line 22 collects charge carriers from the silicon substrate 211, which is detrimental to improving the conversion efficiency of the solar cell. Based on this, in this embodiment, the length L3 of the third printed portion 132b in the first direction X is 0.1 mm to 2 mm and includes any value within this length range, such as 0.1 mm, 1 mm, or 2 mm. When the third printed portion 132b meets the above length range, on the one hand, the length of the second reinforcing portion 12g can be long enough, which is beneficial to improving the lifespan of the printing screen 10. On the other hand, the length of the printed second connection structure can be shorter, which is beneficial to increasing the area where the collector grid line 22 collects charge carriers from the silicon substrate 211, thereby improving the conversion efficiency of the solar cell.

[0192] Considering that if the width W6 of the second printing section 132a in the second direction Y is less than 8μm, the paste has poor passage in the second printing section 132a, resulting in more printing abnormalities, and the size of the second reinforcing section 12g is also small, which leads to a decrease in the service life of the printing screen 10.

[0193] The width W6 of the second printed portion 132a in the second direction Y is greater than 100 μm, and the second connection structure printed by the second printed portion 132a is also relatively wide, resulting in a large light-shielding area, which is not conducive to improving the conversion efficiency of the solar cell. Based on this, in the embodiment of this application, the width W6 of the second printed portion 132a in the second direction Y is 8 μm to 100 μm and includes any value within this width range, such as 8 μm, 50 μm, or 100 μm. When the second printed portion 132a meets the above-mentioned width range, on the one hand, the paste passage of the second printed portion 132a is better, printing abnormalities are less, and the size of the second reinforcing portion 12g is large enough, which is beneficial to improving the service life of the printing screen 10. On the other hand, the width of the second connection structure 23b printed by the second printed portion 132a is moderate, which is also beneficial to the collector grid line 22 collecting carriers from the silicon substrate 211.

[0194] Secondly, referring to Figure 12, this application discloses a printing screen 10, including a screen body 11. The screen body 11 has a printing groove 13 extending along a first direction X, penetrating the thickness direction Z of the screen body 11. The first direction X is perpendicular to the thickness direction of the screen body 11. The printing groove 13 satisfies at least one of the following: In the first direction X, the printing groove 13 has a connected first printing portion 131 and a second printing portion 132a. The first printing portion 131 has a high opening, and the second printing portion 132a has a hollowed-out first reinforcing portion 12f. In the second direction Y, at least partially, the first reinforcing portion 12f is connected between two opposite sides of the second printing portion 132a. In the first direction X, the printing groove 13 has a connected first printing portion 131 and a third printing portion 132b. The first printing portion 131 has a high opening with an opening ratio of 80% to 100%, and the third printing portion 132b has a hollowed-out second reinforcing portion 12g.

[0195] In the second direction Y, at least partially, the second reinforcing portion 12g is connected between the two opposite sides of the third printed portion 132b.

[0196] The first printing section 131 of the printing screen 10 has a high aperture. Due to its high aperture ratio, the first printing section 131 has less obstruction to the ink flow. This characteristic allows the first printing section 131 with a high aperture to be used to print narrower line widths and more regularity collector lines, while also reducing printing defects. Considering that the high-aperture first printing section 131 lacks steel wire traction or the distribution of steel wires providing traction force is relatively sparse, the printing groove 13 of this application also has a second printing section 132a connected to the first printing section 131. The second printing section 132a is provided with a hollowed-out first reinforcing section 12f. In the second direction Y, at least a portion of the first reinforcing section 12f is connected between two opposite sides of the second printing section 132a. The first reinforcing section 12f can provide traction force for the overall mechanical strength of the printing screen 10, thereby enhancing the structural strength of the printing screen 10. The hollowed-out first reinforcing section 12f can also allow paste to pass through, thereby enabling the printing of continuous current collection grid lines, which is beneficial for current collection by the current collection grid lines and can meet the process and testing requirements for energizing solar cells.

[0197] The printing tank 13 of this application also has a third printing section 132b connected to the first printing section 131, and the third printing section 132b is provided with a hollowed-out second reinforcing section 12g. In the second direction Y, at least partially, the second reinforcing section 12g is connected between two opposite sides of the third printing section 132b. The second reinforcing section 12g plays a pulling role, thereby enhancing the structural strength of the printing screen 10. The hollowed-out second reinforcing section 12g can also allow paste to pass through, thereby enabling the printing of continuous current collection grid lines, which is beneficial for current collection by the current collection grid lines and can meet the process and testing requirements for energizing solar cells.

[0198] In summary, the printing screen 10 combines the advantages of high printing quality and high structural strength, and can print continuous collector grid lines, which is beneficial for current collection by the collector grid lines and can meet the process and testing requirements for energizing solar cells.

[0199] Thirdly, embodiments of this application disclose a method for manufacturing a printing screen as described in the first or second aspect, comprising the following steps:

[0200] Provide semi-finished screen printing plates; wherein, the semi-finished screen printing plates have printing grooves;

[0201] A reinforcing section is made on the printing groove.

[0202] This manufacturing method involves creating reinforcing sections on the printing groove. These reinforcing sections exert a pulling effect on the local printing groove, thereby enhancing the structural strength of the printing screen. The hollowed-out reinforcing sections also allow the paste to pass through, enabling the printing of continuous current collection grid lines. This facilitates current collection by the current collection grid lines and meets the process and testing requirements for energizing solar cells.

[0203] In this application, the "screen printing plate semi-finished product" can be one or more metal sublayers. The printing grooves on the screen printing plate semi-finished product can be partial printing grooves or complete printing grooves.

[0204] More specifically, the manufacturing method includes the following steps:

[0205] Fabrication of the insulating layer: A patterned insulating layer is fabricated on a conductive substrate; wherein the pattern of the insulating layer is the same as the pattern of the printing groove.

[0206] Fabrication of the printed molding layer: Electroforming is performed on a conductive substrate with an insulating layer. Electroforming is performed on the insulating layer outside the patterned area to form the printed molding layer. The patterned area of ​​the insulating layer is not electroformed to form partial printing grooves.

[0207] Creating the bonding layer: A bonding layer is created on the surface of the printing molding layer to obtain the screen printing semi-finished product;

[0208] Fabrication of the skeleton layer and reinforcement: A conductive mold corresponding to a portion of the printing groove is placed on the side of the bonding layer away from the printing molding layer. The conductive mold has the same pattern as the reinforcement. The semi-finished screen is electroformed. The skeleton layer is formed after electroforming outside the patterned area of ​​the insulating layer. The reinforcement is integrally formed with the skeleton layer after electroforming on the conductive mold. The remaining printing groove is formed in the patterned area of ​​the insulating layer without electroforming. After electroforming, the insulating layer is removed to obtain the printing screen.

[0209] Using the above-described manufacturing method, a printing molding layer and a bonding layer are first fabricated to obtain a semi-finished screen printing plate. Considering that the printing grooves of the semi-finished screen printing plate are filled with an insulating layer, and the reinforcing part needs to be set corresponding to a portion of the printing grooves, and that electroforming is difficult to achieve on the insulating layer, a conductive mold corresponding to a portion of the printing grooves is placed on the side of the bonding layer away from the printing molding layer. It can be understood that the conductive mold allows for electroforming of a localized area on the surface of the insulating layer. Further, after electroforming on the conductive mold, a reinforcing part integrally formed with the skeleton layer is obtained.

[0210] This manufacturing method allows for the simultaneous fabrication of a high-aperture printing groove and an integrally formed reinforcing section with the skeleton layer, resulting in a printing screen that combines the advantages of high printing quality and high structural strength.

[0211] Of course, reinforcement can also be integrally formed onto the screen printing semi-finished product through methods such as electroplating, laser engraving, or etching. Alternatively, reinforcement can also be fabricated onto the screen printing semi-finished product using non-integral forming methods such as gluing, welding, or lamination.

[0212] Fourthly, as shown in Figures 17 to 20, this application discloses a solar cell 20, including a solar cell preform 21, a current collector grid 22, and connecting structures 23a and 23b. The current collector grid 22 is disposed on the surface of the solar cell preform 21 and extends along a first direction X, which is perpendicular to the thickness direction of the solar cell preform 21. The connecting structures 23a and 23b are disposed on the surface of the solar cell preform 21 and connected to the current collector grid 22. In the thickness direction of the solar cell preform 21, the maximum height of the connecting structures 23a and 23b is greater than the maximum height of the current collector grid 22.

[0213] In the embodiments of this application, the taller connection structures 23a and 23b can have a larger cross-sectional area and a smaller resistance, which is beneficial to improving the transmission capability of the current collected by the collector grid line.

[0214] It should be noted that in this application, the starting point for measuring the height of the connecting structures 23a and 23b and the current collector grid line 22 is the surface of the solar cell preform 21, specifically the surface of the first functional film 213. Furthermore, in this application, because there is a transition region between the current collector grid line 22 and the connecting structures 23a and 23b, the height of this transition region gradually transitions from the height of the current collector grid line 22 to the maximum height of the connecting structures 23a and 23b. Regarding the testing method for the "maximum height," one exemplary testing method for the "maximum height" of the connecting structures 23a and 23b is as follows: using a 3D microscope at 50x or other magnification, a height profile is selected based on the width centerline of the connecting structures 23a and 23b, and a height curve is measured based on the height profile. The height value is then derived from the height curve; for example, this application derives 1024 height point values. It should be noted that, depending on the system settings of different 3D microscope models, any number of height point values ​​can be exported. In order to reduce the impact of abnormal data points on the test, this application needs to remove abnormal height point values. Abnormal data points are defined as height data point values ​​that exceed 30% of the average height point values. For example, assuming the average value of 1024 height point values ​​is Xave, and the abnormal data point is Xi, the height data point value when |Xi-Xave| / Xave>30% belongs to the abnormal height point value described in this application.

[0215] It is understood that the number of data points for testing the "maximum height" is not limited to 1024 points; other numbers of test points can also be used, and this application embodiment does not impose any limitations on this. In this application, the maximum height of the connection structures 23a and 23b is specifically defined, and the coordinate points of the height of the connection structures 23a and 23b are cleaned of abnormal data points, which can reasonably reflect the technical concept of this application. The test method for the "maximum height" of the collector grid line 22 can also adopt a similar test method as described above, and will not be repeated here.

[0216] In some embodiments, referring to FIG17, the solar cell 20 further includes a busbar 24 extending along a second direction Y.

[0217] Connection structures 23a and 23b satisfy at least one of the following:

[0218] The connection structures 23a and 23b include a first connection structure 23a, which is disposed at the intersection of the collector grid line 22 and the bus grid line 24.

[0219] The connection structures 23a and 23b include a second connection structure 23b. In the first direction X, the second connection structure 23b is offset from the busbar 24, and both ends of the second connection structure 23b are connected to the same collector busbar 22.

[0220] It should be noted that there can be multiple connection structures 23a and 23b, including the first connection structure 23a and the second connection structure 23b.

[0221] More specifically, the first connection structure 23a is the centipede-leg grid line mentioned above. For example, the centipede-leg grid line may extend in the same direction as the collector grid line 22, and the line width at the widest point of the centipede-leg grid line may be wider than that of the collector grid line 22. The centipede-leg grid line may be a width-gradient structure.

[0222] The first connection structure 23a contacts the solder strip during the welding process of the busbar 24. The higher first connection structure 23a can provide more grid metal to participate in the silver etching reaction during welding, further reducing the grid breakage phenomenon caused by the silver etching reaction of the collector grid 22.

[0223] The second connection structure 23b is the aforementioned connection gate line. This connection gate line can extend in the same direction as the collector gate line 22 and its two ends are connected to the collector gate line 22, so that the collector gate line 22 is continuous. More specifically, the connection gate line can be a gate line wider than the collector gate line. Of course, the connection gate line can also be a gate line with the same or slightly smaller line width as the collector gate line. The shape of the connection gate line can be a rectangle, a rhombus, or various other shapes. This application embodiment does not limit this.

[0224] In this embodiment, there are multiple collector grid lines 22 and multiple bus grid lines 24. The multiple bus grid lines 24 are spaced apart along the first direction X, and the multiple collector grid lines 22 are spaced apart along the second direction Y. Each collector grid line 22 intersects with the multiple bus grid lines 24, so that the current of each collector grid line 22 can be collected into the multiple bus grid lines 24, which can reduce current loss when a collector grid line 22 is broken.

[0225] Each collector grid line 22 is connected to multiple connection structures 23a and 23b. The multiple connection structures 23a and 23b connected to the same collector grid line 22 include several first connection structures 23a and several second connection structures 23b.

[0226] The collector grid and the first connection structure are described in detail below.

[0227] In some specific embodiments, as shown in Figures 18, 20, 21, and 22, Figure 21 shows that the first connection structure 23a is morphologically taller than the collector grid line 22. Referring to Figure 22, Figures 22(a) and (b) are cross-sectional profiles of the collector grid line 22 and the first connection structure 23a, respectively. In Figure 22(a), the height of the first connection structure is 9.24 μm, and in Figure 22(b), the height of the collector grid line is 5.428 μm. Therefore, it can be seen that the first connection structure 23a, printed in one pass using a printing screen in this application, is taller than the collector grid line 22.

[0228] Referring to Figure 20, the maximum height of the first connection structure 23a is H2, and the maximum height of the collector grid line 22 is H3. Here, H3 / H2 = 20% to 90%, and includes any value within this range, such as 20%, 30%, 60%, or 90%. When the ratio of the maximum height of the first connecting structure 23a to the maximum height of the collector grid line 22 meets the above ratio, on the one hand, the first connecting structure 23a will not be too high, resulting in excessive wet weight of the paste during printing. On the other hand, the first connecting structure 23a has sufficient height to provide enough conductive metal (e.g., silver grid lines formed after silver paste sintering) for welding the first connecting structure 23a to the tin-based alloy on the solder ribbon surface. This will form a conductive interconnection structure between the tin-based alloy and the conductive metal, reducing the grid breakage phenomenon after welding the collector grid line 22. If the height of the first connecting structure 23a is too low (e.g., below 6μm), it will not be able to provide enough conductive metal for welding the first connecting structure 23a to the tin-based alloy on the solder ribbon surface. This will cause the metal on the grid line at the welding point to be completely reacted by the tin-based alloy, and the grid line at the welding point will be misaligned with the solder ribbon connection. Therefore, the charge carriers collected by the collector grid line cannot be successfully transferred to the solder ribbon.

[0229] In other embodiments, the maximum height H2 of the first connecting structure 23a is 3.5 μm to 15 μm and any value within this height range, such as 3.5 μm, 5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm or 15 μm. When the first connection structure 23a meets the above height range, the height of the first connection structure 23a is relatively high, which can provide sufficient conductive metal (such as silver grid lines formed after silver paste sintering) for welding the first connection structure 23a to the tin-based alloy on the surface of the solder strip. This allows for the formation of a conductive interconnection structure between the tin-based alloy and the conductive metal, reducing the grid breakage phenomenon after welding the collector grid line 22. If the height of the first connection structure 23a is low (e.g., below 3.5 μm), it cannot provide sufficient conductive metal for welding the first connection structure 23a to the tin-based alloy on the surface of the solder strip. As a result, the metal on the grid line at the welding point will be completely reacted by the tin-based alloy, and the grid line at the welding point will be misaligned with the connection point of the solder strip. Therefore, the charge carriers collected by the collector grid line cannot be successfully transferred to the solder strip.

[0230] It is understandable that when fabricating collector grid lines with narrow widths (e.g., less than 20 μm), if the height of the collector grid line 22 is less than 3.5 μm, the cross-sectional area of ​​the collector grid line 22 is small, resulting in higher resistance, which is detrimental to the current transmission of the collector grid line. Furthermore, when fabricating narrow collector grid lines, printing defects such as incomplete printing and broken grids are easily caused by screen printing accuracy issues. If the height of the collector grid line 22 is greater than 15 μm, the silver consumption of the collector grid line 22 is large, which is not conducive to reducing the manufacturing cost of solar cells. The maximum height H3 of the collector grid line 22 is 3 μm to 10 μm and any value within this height range, such as 3 μm, 5 μm, 6 μm, 8 μm, or 10 μm.

[0231] When the collector grid line 22 meets the above height range, the collector grid line 22 has low silver loss and low resistance, and can also form a sufficiently large height difference with the connection structures 23a and 23b.

[0232] In this embodiment, the length L4 of the first connecting structure 23a in the first direction X is 0.5mm to 2mm and includes any value within this length range, such as 0.5mm, 1mm, or 2mm. When the first connecting structure 23a meets the above length range, the welding defect rate of the first connecting structure 23a is low and the light-shielding area is small. Further, in the first direction X, the width of the first connecting structure 23a narrows from the middle to both ends. The width W7 at the widest point of the first connecting structure 23a is 10μm to 100μm and includes any value within this width range, such as 10μm, 50μm, or 100μm. The width W8 at the narrowest point of the first connecting structure 23a is 5μm to 60μm and includes any value within this width range, such as 5μm, 30μm, or 60μm. When the first connecting structure 23a meets the above width range, the welding performance of the first connecting structure 23a is good and the light-shielding area is small.

[0233] The second connection structure will be described in detail below.

[0234] In other specific embodiments, as shown in Figures 19 and 22, where Figure 22(c) is a cross-sectional profile of the second connection structure 23b, the height of the collector grid line 22 is 5.428 μm in Figure 22(b), and the height of the second connection structure 23b is 9.078 μm in Figure 22(c). Therefore, it can be seen that the second connection structure 23b, printed in one pass using a printing screen in this application, is taller than the collector grid line 22.

[0235] In other embodiments, the maximum height H4 of the second connection structure 23b is 2μm to 12μm and includes any value within this height range, such as 2μm, 6μm, 10μm, or 12μm. When the second connection structure 23b meets the above height range, the cross-sectional area of ​​the second connection structure 23b is larger, the resistance is lower, the conductivity is better, and the shading of incident light is also lower, so it will not affect the power generation efficiency of the solar cell.

[0236] In other embodiments, the length L5 of the second connecting structure 23b is 0.1mm to 2mm and includes any value within this length range, such as 0.1mm, 1mm, or 2mm. When the second connecting structure 23b meets the above length range, the wet weight of the paste during printing of the second connecting structure 23b is lower, and the light-shielding area of ​​the second connecting structure 23b is also smaller, which is beneficial to improving the conversion efficiency of the solar cell 20.

[0237] In some embodiments, the width W9 of the second connection structure 23b in the second direction Y is 8 μm to 100 μm and includes any value within this width range, such as 8 μm, 50 μm, or 100 μm. When the second connection structure 23b satisfies the above-mentioned width range, the cross-sectional area of ​​the second connection structure 23b is sufficiently large, resulting in low resistance.

[0238] The collector grid is described in detail below.

[0239] In some embodiments, as shown in FIG19, the width W10 of the current collector grid line 22 in the second direction Y is 5μm to 20μm and includes any point value within this width range, such as 5μm, 15μm or 20μm. The current collector grid line 22 with this width range can reduce paste consumption and achieve cost reduction, and also has a lower shading area, thereby contributing to cost reduction and efficiency improvement of the solar cell 20.

[0240] In some embodiments, the grid smoothing factor of the collector grid line 22 is smaller than the grid smoothing factor of the connection structures 23a and 23b. In other embodiments, the solar cell satisfies at least one of the following: the grid smoothing factor of the collector grid line 22 is <1; the grid smoothing factor of the connection structures 23a and 23b is 1 to 8.

[0241] The specific definition of the grid line smoothing factor is as follows: The height profile of the sub-grid is measured using a 3D microscope at any magnification (e.g., 50x). Based on the height curve obtained from the height profile, height coordinate values ​​are derived from the height curve. For example, this application derives 1024 height coordinate point values, and the variance of these 1024 height point values ​​is calculated using the mathematical statistical concept. This variance is used to characterize the fluctuation of the sub-grid height, which is the grid line smoothing factor described in this application. It should be noted that, depending on the system settings of different 3D microscope models, any number of height point values ​​can be derived. To reduce the impact of outlier data points on the calculation of the grid line smoothing factor, this application needs to remove outlier height point values. Outlier data points are defined as height data point values ​​exceeding 30% of the average height point values. For example, assuming the average of the 1024 height point values ​​is Xave, and the outlier data point is Xi, the height point value when |Xi-Xave| / Xave>30% belongs to the outlier height point value described in this application. It is understandable that the smaller the gate smoothing factor, the better the smoothness of the gate line and the better the current transmission capability of the gate line.

[0242] In other words, the collector grid line 22 can have a smaller smoothness and a smoother height profile curve. As a result, the resistance loss of the collector grid line 22 per unit weight of grid line metal material is also smaller, thereby improving the current transmission capability of the solar cell 20.

[0243] It should be noted that the solar cell pre-product 21 refers to the semi-finished product of the solar cell 20, such as the semi-finished product obtained after the front and back coating process of the solar cell.

[0244] In some embodiments, referring to FIG20, the solar cell preform 21 includes a silicon substrate 211, a doped layer 212 and a first functional film 213, wherein the doped layer 212 and the first functional film 213 are disposed on the surface of the silicon substrate 211 in a direction away from the silicon substrate 211.

[0245] The connection structures 23a, 23b and the collector grid line 22 are all disposed on the first functional film 213 and penetrate the first functional film 213 to make ohmic contact with the doped layer 212.

[0246] It is understandable that the connection structures 23a and 23b and the current collector line 22 can be printed using the same printing screen. Accordingly, the connection structures 23a and 23b and the current collector line 22 use the same paste. In some embodiments, this paste uses glass frit, which burns through the first functional film during sintering to form an ohmic contact with the doped layer. That is, like the current collector line 22, the connection structures 23a and 23b burn through the first functional film and form an ohmic structure with the doped layer. The connection structures 23a and 23b can collect current from the doped layer, thereby improving the overall current collection efficiency of the solar cell 20 and contributing to increased efficiency.

[0247] For example, the doped layer 212 is, for instance, a diffusion layer or a first doped polysilicon layer. The diffusion layer is, for instance, a boron-doped layer or a phosphorus-doped layer. The conductivity type of the first doped polysilicon layer can be N-type or P-type. The first functional film 213 is, for instance, at least one of a passivation film and an antireflection film. More specifically, the material of the first functional film 213 can be silicon nitride, silicon oxide, silicon oxynitride, or aluminum oxide, etc., which is not limited in this embodiment. The silicon substrate 211 can be an N-type silicon substrate or a P-type silicon substrate, which is not limited in this embodiment.

[0248] More specifically, the solar cell 20 can be a passivated contact solar cell or a heterojunction solar cell, etc., and this application embodiment does not limit this. When the solar cell 20 is a passivated contact solar cell 20, the doped layer 212 and the first functional film 213 can be disposed on one side of the silicon substrate 211, such as the front or back side of the silicon substrate 211. In addition, it should be noted that although the front and back sides of the silicon substrate 211 are flat in the drawings, at least one of the front and back sides of the silicon substrate 211 can also be textured. Further, the solar cell preform 21 also includes an interface passivation layer 214, a second doped polycrystalline silicon layer 215, and a second functional film 216, which are sequentially stacked on the side of the silicon substrate 211 opposite to the doped layer 212 along a direction away from the silicon substrate 211.

[0249] More specifically, the material of the interface passivation layer 214 may include a variety of dielectric materials, such as at least one selected from silicon oxide, magnesium fluoride, amorphous silicon, hydrogenated amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, or titanium oxide. In some embodiments, the interface passivation layer 214 may be composed of a silicon oxide layer containing silicon oxide. This is because the silicon oxide layer has excellent passivation properties, can minimize the recombination loss of minority carriers on the surface of the silicon substrate 211, and is a thin film with excellent durability for subsequent high-temperature processes. The interface passivation layer 214, acting as a barrier for electrons and holes, can be combined with the second doped polycrystalline silicon layer 215 to prevent minority carriers from passing through.

[0250] The interface passivation layer 214 can also function as a pinhole channel, allowing charge carriers within the solar cell 20 to move freely and selectively pass through the second doped polysilicon layer 215, which helps reduce recombination losses of minority carriers. Additionally, the interface passivation layer 214 can act as a diffusion barrier to prevent the dopants in the second doped polysilicon layer 215 from diffusing into the silicon substrate 211.

[0251] The conductivity type of the second doped polysilicon layer 215 can be N-type or P-type. The conductivity type of the second doped polysilicon layer 215 is opposite to that of the doped layer. The second functional film 216 is, for example, at least one of a passivation film and an antireflection film. More specifically, the material of the second functional film 216 can be silicon nitride, silicon oxide, silicon oxynitride, or aluminum oxide, etc., and this embodiment of the application does not limit this.

[0252] Fifthly, as shown in FIG23, an embodiment of this application discloses a photovoltaic module, including a plurality of solar cells 20 connected in series and / or in parallel, wherein at least one solar cell 20 is obtained by printing using a screen printing plate as described in the first or second aspect; or, at least one solar cell 20 is obtained by printing using a screen printing plate made by the manufacturing method described in the third aspect; or, at least one solar cell 20 is the solar cell 20 described in the fourth aspect.

[0253] For example, two solar cells 20 are connected in series and / or in parallel via an electrical connector 40. The electrical connector 40 may be a solder strip.

[0254] 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: A screen printing plate body, wherein a printing groove is provided on the screen printing plate body extending along a first direction, the printing groove penetrating the screen printing plate body along the thickness direction of the screen printing plate body, and the first direction is perpendicular to the thickness direction of the screen printing plate body; as well as The reinforcing part is at least partially disposed at the position where the printing groove is located on the screen body. The reinforcing part is disposed in relation to the printing groove. At least part of the reinforcing part is hollowed out and the hollowed-out part of the reinforcing part is connected to the printing groove.

2. The printing screen according to claim 1, characterized in that, In a second direction, the reinforcing portion is disposed between two opposite sides of the printing groove; wherein the second direction intersects with the first direction.

3. The printing screen according to claim 1, characterized in that, The printing groove has a first opening section and a second opening section in the first direction, and the reinforcing part is located between the first opening section and the second opening section.

4. The printing screen according to claim 1, characterized in that, The reinforcing part includes at least one of the following: finger structure, grid structure, honeycomb structure, ring structure, or polygonal structure.

5. The printing screen according to claim 1, characterized in that, The reinforcing section has multiple linear substructures, which are spaced apart to form a hollow area; or, the multiple linear substructures are connected to form a hollow area; the hollow area is connected to the printing groove; the cross-sectional area of ​​the linear substructure is 16 μm. 2 ~225μm 2 The cross section is a plane formed by the first direction and the thickness direction of the screen body.

6. The printing screen according to claim 4, characterized in that, When the reinforcing part is the finger-shaped structure, the finger-shaped structure includes a plurality of linear substructures; the plurality of linear substructures are spaced apart in the first direction, and a hollow area is formed between two adjacent linear substructures, the hollow area being connected to the printing groove; In the second direction, each of the linear substructures traverses the printing groove, and each of the linear substructures is disposed between two opposite sides of the printing groove; wherein the second direction intersects the first direction.

7. The printing screen according to claim 6, characterized in that, The dimension of the printing groove in the second direction is the width; in the first direction, the portion of the printing groove corresponding to the reinforcing part is constructed as a width gradient part, and the spacing between two adjacent linear substructures increases as the width of the width gradient part narrows.

8. The printing screen according to claim 6, characterized in that, The linear substructure satisfies at least one of the following: The diameter of the linear substructure is 6 μm to 15 μm; The spacing D1 between two adjacent linear substructures is 0.042 mm to 0.084 mm.

9. The printing screen according to claim 4, characterized in that, When the reinforcing part is the honeycomb structure, in the second direction, the honeycomb structure is disposed between two opposite sides of a portion of the printing groove; the honeycomb structure includes a plurality of honeycomb grids, the inner peripheral area of ​​each honeycomb grid is a hollow area, and the hollow area is connected to the printing groove; wherein, the second direction intersects with the first direction.

10. The printing screen according to any one of claims 1 to 9, characterized in that, The screen printing body includes multiple metal sub-layers, which are stacked sequentially in the thickness direction of the screen printing body. The plurality of metal sub-layers include a printing shaping layer and a skeleton layer. In the slurry feeding direction of the screen body, the skeleton layer is located behind the printing shaping layer, and the reinforcing part is disposed on the skeleton layer.

11. The printing screen according to claim 10, characterized in that, In the first direction, the portion of the printing groove that is offset from the reinforcing part is the first printing part, and the dimension of the first printing part in the second direction is the width, and the second direction intersects with the first direction; The width of the first printed part in the printed molding layer is W1, and the width of the first printed part in the skeleton layer is W2; wherein, W2∶W1=(13~23)∶1.

12. The printing screen according to claim 11, characterized in that, The width W1 of the first printed part in the printed molding layer is 3μm to 15μm, and the width W2 of the first printed part in the skeleton layer is 100μm to 150μm.

13. The printing screen according to claim 10, characterized in that, The portion of the printing groove corresponding to the reinforcing part is constructed as a narrowing portion in the skeleton layer. The width of the narrowing portion is the width in the second direction, and the width of the narrowing portion narrows along the feeding direction of the screen body; wherein the second direction intersects the first direction.

14. The printing screen according to claim 10, characterized in that, The plurality of metal sublayers also include a bonding layer, which connects the skeleton layer and the printing shaping layer in the thickness direction of the screen body.

15. The printing screen according to claim 14, characterized in that, The printed shaping layer satisfies at least one of the following: The printed molding layer is made of a nickel alloy; The thickness T1 of the printed molding layer is 2μm to 20μm; The skeleton layer satisfies at least one of the following: The skeleton layer is made of nickel alloy; The thickness T2 of the skeleton layer is 2μm to 20μm; The bonding layer satisfies at least one of the following: The material of the bonding layer is selected from at least one of nickel or copper; The thickness T3 of the bonding layer is 70nm to 80nm.

16. The printing screen according to any one of claims 1 to 9, characterized in that, In the first direction, the portion of the printed groove that is offset from the reinforcing portion is configured as the current collector grid line of the printed solar cell; the reinforcing portion satisfies at least one of the following: The reinforcing portion includes a first reinforcing portion, which is configured as a first connection structure printed on the current collector line, and the first connection structure is disposed at the intersection of the current collector line and the busbar line. The reinforcing portion includes a second reinforcing portion, which is configured as a second connection structure printed on the collector grid line. In the first direction, the second connection structure is offset from the bus grid line and both ends of the second connection structure are connected to the same collector grid line.

17. The printing screen according to claim 16, characterized in that, When the reinforcing portion includes a first reinforcing portion, the portion of the printing groove corresponding to the first reinforcing portion is a second printing portion; the second printing portion satisfies at least one of the following: The length L2 of the second printing section in the first direction is 0.3mm to 2mm; The second printing part has a width in the second direction; in the first direction, the width of the second printing part narrows from the middle to both ends, the width W4 at the widest point of the second printing part is 10μm to 100μm, and the width W5 at the narrowest point of the second printing part is 5μm to 60μm; wherein, the first direction intersects the second direction; When the reinforcing part includes the second reinforcing part, the portion of the printing groove corresponding to the second reinforcing part is the third printing part. The length L3 of the third printing part in the first direction is 0.1 mm to 2 mm, and the width W6 of the third printing part in the second direction is 8 μm to 100 μm.

18. The printing screen according to any one of claims 1 to 9, characterized in that, In the first direction, the portion of the printing groove that is offset from the reinforcing portion is the first printing portion, and the opening ratio of the first printing portion is 80% to 100%; the opening ratio of the reinforcing portion is 30% to 70%.

19. The printing screen according to any one of claims 1 to 9, characterized in that, The plurality of reinforcing portions are disposed corresponding to the same printing groove, and the plurality of reinforcing portions are spaced apart in the first direction.

20. The printing screen according to claim 19, characterized in that, In the first direction, the size of the main body of the screen is D2, the distance between two adjacent reinforcing parts is D3, and D3 / D2 = 1% to 20%.

21. The printing screen according to claim 16, characterized in that, The printing screen plate satisfies at least one of the following: In the first direction, the size D2 of the screen body is 166mm to 230mm, and the distance D3 between two adjacent reinforcing parts is 3mm to 50mm; Of two adjacent reinforcing portions on the same printing groove, one reinforcing portion is configured such that a printed connecting structure is disposed at the intersection of the current collector line and the current bus line, and the other reinforcing portion is configured such that the printed connecting structure is offset from the current bus line, wherein the connecting structure is either the first connecting structure or the second connecting structure.

22. The printing screen according to any one of claims 1 to 9, characterized in that, The printing screen plate satisfies at least one of the following: The reinforcing part is disposed between at least one or both sides of the screen body in the thickness direction; There are multiple printing grooves, which are spaced apart in a second direction, and the second direction intersects with the first direction.

23. A printing screen, characterized in that, include: A screen printing plate body, wherein the screen printing plate body is provided with a printing groove extending along a first direction, the printing groove penetrating through the thickness direction of the screen printing plate body, the first direction being perpendicular to the thickness direction of the screen printing plate body; the printing groove satisfies at least one of the following: In the first direction, the printing groove has a first printing section and a second printing section connected together, the first printing section having an opening ratio of 80% to 100%, and the second printing section having a hollowed-out first reinforcing section; in the second direction, the first reinforcing section is at least partially connected between two opposite sides of the second printing section; wherein, the second direction intersects with the first direction; In the first direction, the printing groove has a first printing section and a third printing section connected together, the first printing section having an opening ratio of 80% to 100%, and the third printing section having a hollowed-out second reinforcing section; in the second direction, the second reinforcing section is at least partially connected between two opposite sides of the third printing section.

24. A method for manufacturing a printing screen as described in any one of claims 1 to 23, characterized in that, Includes the following steps: Provide a semi-finished screen printing plate having the aforementioned printing groove; The reinforcing portion is fabricated on the printing groove.

25. A solar cell, characterized in that, The solar cell is obtained by printing using a screen printing plate as described in any one of claims 1 to 23; or, the solar cell is obtained by printing using a screen printing plate prepared by the manufacturing method as described in claim 24, wherein the solar cell comprises: Solar cell preforms; A current collector grid line is disposed on the surface of the solar cell preform and extends along a first direction perpendicular to the thickness direction of the solar cell preform; and A connection structure is disposed on the surface of the solar cell preform and connected to the current collector grid line; in the thickness direction of the solar cell preform, the maximum height of the connection structure is greater than the maximum height of the current collector grid line.

26. The solar cell according to claim 25, characterized in that, The solar cell further includes a busbar extending along a second direction, which intersects the first direction; the connection structure satisfies at least one of the following: The connection structure includes a first connection structure, which is disposed at the intersection of the current collector grid line and the current collector grid line. The connection structure includes a second connection structure. In the first direction, the second connection structure is offset from the busbar and both ends of the second connection structure are connected to the same collector line.

27. The solar cell according to claim 26, characterized in that, When the connection structure includes the first connection structure, the maximum height of the first connection structure is H2, and the maximum height of the collector grid line is H3; wherein, H3 / H2 = 20% to 90%.

28. The solar cell according to claim 26, characterized in that, The solar cell satisfies at least one of the following: The maximum height H2 of the first connecting structure is 3.5 μm to 15 μm; The maximum height H3 of the collector grid line is 3μm to 10μm.

29. The solar cell according to claim 26, characterized in that, When the connection structure includes the first connection structure, the first connection structure satisfies at least one of the following: The length L4 of the first connecting structure in the first direction is 0.5mm to 2mm; In the first direction, the width of the first connecting structure narrows from the middle to both ends, the width W7 at the widest point of the first connecting structure is 10μm to 100μm, and the width W8 at the narrowest point of the first connecting structure is 5μm to 60μm.

30. The solar cell according to claim 26, characterized in that, When the connection structure includes the second connection structure, the solar cell satisfies at least one of the following: The length L5 of the second connecting structure is 0.1mm to 2mm; The width W9 of the second connection structure in the second direction is 8μm to 100μm; The maximum height H4 of the second connecting structure is 2μm to 12μm; The width W10 of the collector grid line in the second direction is 5μm to 20μm.

31. The solar cell according to any one of claims 26 to 30, characterized in that, The number of collector grid lines and the number of bus grid lines are both multiple. The multiple bus grid lines are spaced apart along the first direction, and the multiple collector grid lines are spaced apart along the second direction. Each of the collector grid lines intersects with the multiple bus grid lines. Each of the collector grid lines is connected to a plurality of the connection structures. The plurality of connection structures connected to the same collector grid line include a plurality of first connection structures and a plurality of second connection structures. Each first connection structure is disposed at the intersection of the collector grid line and each of the bus grid lines. In a first direction, each second connection structure is located between two adjacent bus grid lines and both ends of the second connection structure are connected to the collector grid line. Wherein, the first direction is perpendicular to the second direction.

32. The solar cell according to any one of claims 25 to 30, characterized in that, The gate line smoothing factor of the collector gate line is less than the gate line smoothing factor of the connection structure.

33. The solar cell according to any one of claims 25 to 30, characterized in that, The solar cell satisfies at least one of the following: The grid line smoothing factor of the collector grid line is <1; The smoothing factor of the gate line in the connection structure is 1 to 8.

34. The solar cell according to any one of claims 25 to 30, characterized in that, The solar cell preform includes a silicon substrate, a doped layer, and a first functional film, wherein the doped layer and the first functional film are disposed on the surface of the silicon substrate in a direction away from the silicon substrate. Both the connection structure and the collector grid line are disposed on the first functional film and penetrate the first functional film to make ohmic contact with the doped layer.

35. A photovoltaic module, characterized in that, It includes a plurality of solar cells, wherein any two solar cells are connected in at least one of series and parallel connection, and at least one solar cell is obtained by printing using a screen printing plate as described in any one of claims 1 to 23; or, at least one solar cell is obtained by printing using a screen printing plate made by the manufacturing method described in claim 24; or, at least one solar cell is a solar cell as described in any one of claims 25 to 34.

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