Screen printing plate, manufacturing method, solar cell and photovoltaic module

Abstract

The invention relates to the technical field of screen printing plates, in particular to a printing screen printing plate, a manufacturing method, a solar cell and a photovoltaic module. The printing screen comprises a screen body and a reinforcing part. A printing groove extending in the first direction is formed in the screen printing plate body and penetrates through the thickness direction of the screen printing plate body. The reinforcing part is arranged at the position, provided with the printing groove, of the screen printing plate body, the reinforcing part is arranged corresponding to the part of the printing groove, at least part of the reinforcing part is hollowed out, and the hollowed-out position of the reinforcing part is communicated with the printing groove. The printing screen has the advantages of high printing quality and high structural strength, can print continuous current collection grid lines, facilitates current collection of the current collection grid lines, and can meet the process and test requirements of electrifying a solar cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of screen printing, and in particular to a printing screen, a manufacturing method, a solar cell and a photovoltaic module. BACKGROUND

[0002] The current collecting grid lines of a solar cell can be printed by a printing screen. The printing screen is provided with printing grooves in the same pattern as the current collecting grid lines. However, the current collecting grid lines are relatively long, for example, the length of the current collecting grid lines is only slightly smaller than the size of the solar cell. Correspondingly, the printing grooves on the printing screen are also relatively long, which can easily lead to a decrease in the structural strength of the printing screen, and further lead to a decrease in the service life of the printing screen. SUMMARY

[0003] The present application discloses a printing screen, a manufacturing method, a solar cell and a photovoltaic module, which can balance the advantages of high printing quality and high structural strength, and can print current collecting grid lines with continuous structures, which is beneficial to current collection of the current collecting grid lines, and can meet the process and test requirements of energizing the solar cell.

[0004] To achieve the above object, in a first aspect, the present application discloses a printing screen, comprising:

[0005] a screen body, the screen body being provided with a printing groove extending along a first direction, the printing groove penetrating through the screen body along the thickness direction of the screen body; and

[0006] a reinforcing portion, the reinforcing portion being arranged at the position of the screen body provided with the printing groove, the reinforcing portion being arranged corresponding to the part of the printing groove, the reinforcing portion being at least partially hollow, and the hollow part of the reinforcing portion being in communication with the printing groove.

[0007] In a possible implementation manner of the first aspect, in a second direction, the reinforcing portion is arranged between two opposite sides of the printing groove; and the second direction intersects the first direction.

[0008] In a possible implementation manner of the first aspect, the reinforcing portion is arranged corresponding to the part of the printing groove along the first direction, so that the printing groove has a first opening section and a second opening section in the first direction, and the reinforcing portion is located between the first opening section and the second opening section.

[0009] In a possible implementation manner of the first aspect, the reinforcing portion comprises at least one of a comb structure, a grid structure, a honeycomb structure, a ring structure or a fold line structure.

[0010] In a possible implementation manner of the first aspect, the reinforcing portion has a plurality of linear substructures, the plurality of linear substructures are arranged at intervals to form a hollow region, or the plurality of linear substructures are connected to form a hollow region, and the hollow region is in communication with the printing groove.

[0011] The linear substructure has a cross-sectional area of 16 μm 2 ~ 225 μm 2 The cross section is a plane formed by the first direction and a thickness direction of the screen body.

[0012] In a possible implementation manner of the first aspect, when the reinforcing portion is the comb structure, the comb structure includes a plurality of linear substructures, the plurality of linear substructures are arranged at intervals in the first direction, a hollow region is formed between two adjacent linear substructures, and the hollow region is in communication with the printing groove.

[0013] In the second direction, each linear substructure traverses the printing groove, and each linear substructure is arranged between two opposite sides of the printing groove.

[0014] The second direction intersects the first direction.

[0015] In a possible implementation manner of the first aspect, a size of the printing groove in the second direction is a width, and in the first direction, a part of the printing groove corresponding to the reinforcing portion is configured as a width tapering portion, and a distance between two adjacent linear substructures increases as the width tapering portion narrows.

[0016] In a possible implementation manner of the first aspect, a wire diameter of the linear substructure is 3.5 μm ~ 20 μm.

[0017] And / or, a distance D1 between two adjacent linear substructures is 0.042 mm ~ 0.084 mm.

[0018] In a possible implementation manner of the first aspect, when the reinforcing portion is the honeycomb structure, in the second direction, the honeycomb structure is arranged between two opposite sides of part of the printing groove, the honeycomb structure includes a plurality of honeycomb grids, an inner circumferential region of each honeycomb grid is a hollow region, the hollow region is in communication with the printing groove, and the second direction intersects the first direction.

[0019] In a possible implementation manner of the first aspect, the screen body includes a plurality of metal sub-layers, and the plurality of metal sub-layers are sequentially stacked in a thickness direction of the screen body.

[0020] The plurality of metal sub-layers include a printing shaping layer and a framework layer, the framework layer is located in front of the printing shaping layer in a feeding direction of the screen body, and the reinforcing part is arranged on the framework layer.

[0021] In a possible implementation manner of the first aspect, in the first direction, the part where the printing groove is staggered with the reinforcing part is a first printing part, and a dimension of the first printing part in a second direction is a width, the second direction intersects the first direction.

[0022] The width of the first printing part in the printing shaping layer is W1, and the width of the first printing part in the framework layer is W2; and W2:W1=(13-23):1.

[0023] In a possible implementation manner of the first aspect, the width W1 of the first printing part in the printing shaping layer is 3-15 μm, and the width W2 of the first printing part in the framework layer is 100-150 μm.

[0024] In a possible implementation manner of the first aspect, the part where the printing groove is arranged corresponding to the reinforcing part is configured as a width narrowing part in the framework layer, a dimension of the width narrowing part in a second direction is a width, and the width of the width narrowing part narrows along the feeding direction of the screen body; and the second direction intersects the first direction.

[0025] In a possible implementation manner of the first aspect, the plurality of metal sub-layers further include a bonding layer, the bonding layer is connected between the framework layer and the printing shaping layer in a thickness direction of the screen body.

[0026] In a possible implementation manner of the first aspect, the material of the printing shaping layer is a nickel alloy.

[0027] And / or, the thickness T1 of the printing shaping layer is 2-20 μm.

[0028] And / or, the material of the framework layer is a nickel alloy.

[0029] And / or, the thickness T2 of the framework layer is 2-20 μm.

[0030] And / or, the material of the bonding layer is selected from at least one of nickel or copper.

[0031] And / or, the thickness T3 of the bonding layer is 70-80 nm.

[0032] In a possible implementation manner of the first aspect, in the first direction, the part where the printing groove is staggered with the reinforcing part is configured as a current collecting grid line of a solar cell.

[0033] The reinforcing portion comprises a first reinforcing portion configured to print a first connecting structure connected to the current collecting grid line, the first connecting structure being arranged at an intersection of the current collecting grid line and a bus grid line;

[0034] And / or, the reinforcing portion comprises a second reinforcing portion configured to print a second connecting structure connected to the current collecting grid line, the second connecting structure being staggered with a bus grid line in the first direction and both ends of the second connecting structure being connected to the same current collecting grid line.

[0035] In a possible implementation of the first aspect, when the reinforcing portion comprises a first reinforcing portion, a part of the printing groove corresponding to the first reinforcing portion is a second printed part; a length L2 of the second printed part in the first direction is 0.3mm-2mm; and / or, a dimension of the second printed part in the second direction is a width; in the first direction, the width of the second printed part narrows from the middle to both ends, a width W4 of the widest part of the second printed part is 10μm-100μm, and a width W5 of the narrowest part of the second printed part is 5μm-60μm;

[0036] And / or, when the reinforcing portion comprises a second reinforcing portion, a part of the printing groove corresponding to the second reinforcing portion is a third printed part, a length L3 of the third printed part in the first direction is 0.1mm-2mm, and a width W6 of the third printed part in the second direction is 8μm-100μm;

[0037] Wherein, the first direction intersects the second direction.

[0038] In a possible implementation of the first aspect, in the first direction, a part of the printing groove staggered with the reinforcing portion is a first printed part, and an opening rate of the first printed part is 80%-100%; and an opening rate of the reinforcing portion is 30%-70%.

[0039] In a possible implementation of the first aspect, a plurality of the reinforcing portions are arranged corresponding to the same printing groove, and the plurality of the reinforcing portions are arranged at intervals in the first direction.

[0040] In a possible implementation of the first aspect, in the first direction, a dimension of the screen printing plate body is D2, a distance between two adjacent reinforcing portions is D3, and D3 / D2=1%-20%.

[0041] In a possible implementation of the first aspect, in the first direction, a dimension D2 of the screen printing plate body is 166mm-230mm, and a distance D3 between two adjacent reinforcing portions is 3mm-50mm.

[0042] And / or, in two adjacent reinforcing portions on the same printing slot, one of the reinforcing portions is configured to print the connection structure at the intersection of the current collecting grid line and the bus grid line, and the other reinforcing portion is configured to print the connection structure staggered with the bus grid line.

[0043] In a possible implementation of the first aspect, the reinforcing portion is arranged between at least one side or both sides in the thickness direction of the screen body.

[0044] And / or, the printing slot is a plurality of, and the plurality of printing slots are arranged at intervals in the second direction intersecting the first direction.

[0045] In a second aspect, the embodiments of the present application disclose a printing screen, comprising:

[0046] A screen body, wherein the screen body is provided with a printing slot extending in a first direction, and the printing slot penetrates through the thickness direction of the screen body;

[0047] In the first direction, the printing slot has a first printing portion and a second printing portion connected in sequence, the first printing portion is a high opening with an opening rate of 80% to 100%, and the second printing portion is provided with a first reinforcing portion in hollow; in a second direction, the first reinforcing portion is at least partially connected between two opposite sides of the second printing portion;

[0048] And / or,

[0049] In the first direction, the printing slot has a first printing portion and a third printing portion connected in sequence, the first printing portion is a high opening with an opening rate of 80% to 100%, and the third printing portion is provided with a second reinforcing portion in hollow; in a second direction, the second reinforcing portion is at least partially connected between two opposite sides of the third printing portion;

[0050] Wherein, the second direction intersects the first direction.

[0051] In a third aspect, the embodiments of the present application disclose a manufacturing method of the printing screen according to the first aspect or the second aspect, comprising the following steps:

[0052] Providing a screen semi-finished product with the printing slot;

[0053] Manufacturing the reinforcing portion on the printing slot.

[0054] In a fourth aspect, the embodiments of the present application disclose a solar cell, comprising:

[0055] A solar cell preform;

[0056] A collector grid line is arranged on a surface of the solar cell pre-product and extends along the first direction; and

[0057] The connecting structure is arranged on a surface of the solar cell pre-product and connected to the collector grid line; in a thickness direction of the solar cell pre-product, a maximum height of the connecting structure is greater than a height of the collector grid line.

[0058] In a possible implementation manner of the fourth aspect, the solar cell further includes a bus grid line extending along a second direction, the second direction intersecting the first direction;

[0059] The connecting structure includes a first connecting structure arranged at an intersection of the collector grid line and the bus grid line;

[0060] And / or,

[0061] The connecting structure includes a second connecting structure, in the first direction, the second connecting structure is staggered with the bus grid line and both ends of the second connecting structure are connected to the collector grid line.

[0062] In a possible implementation manner of the fourth aspect, when the connecting structure includes the first connecting structure, a maximum height of the first connecting structure is H2, and a height of the collector grid line is H3; wherein H3 / H2 = 20% to 90%.

[0063] In a possible implementation manner of the fourth aspect, the maximum height H2 of the first connecting structure is 3.5 μm to 15 μm; and / or, the height H3 of the collector grid line is 3 μm to 10 μm.

[0064] In a possible implementation manner of the fourth aspect, when the connecting structure includes the first connecting structure, a length L4 of the first connecting structure in the first direction is 0.5 mm to 2 mm;

[0065] And / or, in the first direction, a width of the first connecting structure narrows from a middle part to both ends, a width W7 of the first connecting structure at a widest part is 10 μm to 100 μm, and a width W8 of the first connecting structure at a narrowest part is 5 μm to 60 μm.

[0066] In a possible implementation manner of the fourth aspect, when the connecting structure includes the second connecting structure, a length L5 of the second connecting structure is 0.1 mm to 2 mm;

[0067] And / or, a width W9 of the second connecting structure is 8 μm to 100 μm;

[0068] And / or, the maximum height H4 of the second connection structure is 2 μm-12 μm.

[0069] And / or, the width W10 of the current collecting grid line is 5 μm-20 μm.

[0070] In a possible implementation of the fourth aspect, the number of the current collecting grid lines and the number of the bus grid lines are both plural, the bus grid lines are spaced apart along the first direction, the current collecting grid lines are spaced apart along the second direction, and each current collecting grid line intersects with the bus grid lines.

[0071] Each current collecting grid line is connected with a plurality of connection structures, the connection structures connected with the same current collecting grid line include first connection structures and second connection structures, each first connection structure is arranged at the intersection of the current collecting grid line and the bus grid line, and in the first direction, each second connection structure is located between two adjacent bus grid lines and both ends of the second connection structure are connected with the current collecting grid line.

[0072] The first direction is perpendicular to the second direction.

[0073] In a possible implementation of the fourth aspect, the grid line smoothness factor of the current collecting grid line is less than the grid line smoothness factor of the connection structure.

[0074] In a possible implementation of the fourth aspect, the grid line smoothness factor of the current collecting grid line is less than 1; and / or, the grid line smoothness factor of the connection structure is 1-8.

[0075] In a possible implementation of the fourth aspect, the solar cell pre-product includes a silicon substrate, a doped layer, and a first functional film, the doped layer and the first functional film are arranged on the surface of the silicon substrate in a direction away from the silicon substrate.

[0076] The connection structure and the current collecting grid line are both arranged on the first functional film and in ohmic contact with the doped layer through the first functional film.

[0077] In the fifth aspect, the embodiments of the present application disclose a photovoltaic module, which includes a plurality of solar cells connected in series and / or in parallel, at least one of the solar cells is printed by using the printing screen plate as described in the first aspect or the second aspect; or, at least one of the solar cells is printed by using the printing screen plate manufactured by the manufacturing method as described in the third aspect; or, at least one of the solar cells is the solar cell as described in the fourth aspect.

[0078] Compared with the prior art, the present application has the following beneficial effects:

[0079] The printing screen disclosed in the application is provided with a reinforcing part, so that the reinforcing part is arranged corresponding to the printing groove, that is, the reinforcing part can structurally reinforce the screen body at the position of the printing groove, thereby improving the structural strength of the screen body. On this basis, in order to realize the printing continuity of the printing groove, the structure of the reinforcing part is designed, so that the reinforcing part is at least partially hollow and the hollow part of the reinforcing part is in communication with the printing groove. In other words, the paste can be printed through the reinforcing part to obtain a connecting structure connected to the current collecting grid line, so as to realize the electrical interconnection between the current collecting grid line and the bus grid line through the connecting structure, which is conducive to transmitting the current collected by the current collecting grid line to the bus grid line and can meet the process and test requirements of energizing the solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0080] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0081] Figure 1 A structural schematic diagram of a high-opening ratio screen (high-opening printing groove is continuous) in the related art;

[0082] Figure 2 A structural schematic diagram of a high-opening ratio screen (high-opening printing groove is discontinuous) in the related art;

[0083] Figure 3 A front view of one structure of the printing screen disclosed in the application;

[0084] Figure 4 A front view of another structure of the printing screen disclosed in the application;

[0085] Figure 5 A sectional view of one structure of the printing screen disclosed in the application;

[0086] Figure 6 A sectional view of another structure of the printing screen disclosed in the application;

[0087] Figure 7 A structural schematic diagram of the reinforcing part being a comb structure;

[0088] Figure 8 A structural schematic diagram of the reinforcing part being a honeycomb structure;

[0089] Figure 9 A structural schematic diagram of the reinforcing part being a grid structure;

[0090] Figure 10 Structure diagram of the reinforcing part of the present application in a loop structure;

[0091] Figure 11 Structure diagram of the reinforcing part of the present application in a zigzag structure;

[0092] Figure 12 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application;

[0093] Figure 13 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application; Figure 12 Enlarged view of the I area shown in FIG. 1;

[0094] Figure 14 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application; Figure 13 Cross-sectional view of A-A shown in FIG. 1;

[0095] Figure 15 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application; Figure 12 Cross-sectional view of B-B shown in FIG. 1;

[0096] Figure 16 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application;

[0097] Figure 17 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application;

[0098] Figure 18 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application; Figure 17 Enlarged view of the II area shown in FIG. 1;

[0099] Figure 19 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application; Figure 17 Enlarged view of the III area shown in FIG. 1;

[0100] Figure 20 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application; Figure 17 Cross-sectional view of C-C shown in FIG. 1;

[0101] Figure 21 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application;

[0102] Figure 22 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application;

[0103] Figure 23 Structure diagram of the printing screen (the reinforcing part is in a comb structure) of the present application;

[0104] Explanation of reference signs:

[0105] 10, printing screen; 11, screen body; 111, printing shaping layer; 112, framework layer; 113, bonding layer; 12, reinforcing part; 12a, comb structure; 12b, honeycomb structure; 12c, grid structure; 12d, ring structure; 12e, fold line structure; 12f, first reinforcing part; 12g, second reinforcing part; 121, linear substructure; 122, hollowed-out area; 123, honeycomb grid; 13, printing slot; 131, first printing part; 132a, second printing part; 132b, third printing part; 133, first opening section; 134, second opening section; 135, width gradual change part; 136, width narrowing part; X, first direction; Y, second direction; Z, thickness direction of screen body;

[0106] 20, solar cell; 21, solar cell preform; 211, silicon substrate; 212, doped layer; 213, first functional film; 214, interface passivation layer; 215, second doped polysilicon layer; 216, second functional film; 22, collector grid line; 23a, 23b, connection structure; 23a, first connection structure; 23b, second connection structure; 24, busbar grid line;

[0107] 30, high opening rate screen; 31, high opening printing slot;

[0108] 40, electrical connector. DETAILED DESCRIPTION

[0109] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work belong to the scope of protection of the present application.

[0110] In the present application, the terms "upper", "inner", "outer", "front", etc. indicate the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0111] In addition, in addition to indicating the orientation or positional relationship, the above-mentioned part of the terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. For those skilled in the art, the specific meaning of these terms in the present application can be understood according to the specific situation.

[0112] In addition, the terms "set", "provided with", "connected", "linked" should be understood broadly. For example, it can be fixed connection, detachable connection, or integral structure; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or internal communication between two devices, elements or components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0113] In addition, the terms "first", "second" and the like are mainly used to distinguish different devices, elements or components (the specific type and structure may be the same or different), and are not intended to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise stated, the meaning of "multiple" is two or more.

[0114] The collecting grid lines of the solar cell can be printed by a screen. Taking a steel screen as an example, the paste is printed on the solar cell preform through the printing slot on the steel screen. The pattern of the printing slot is consistent with the pattern of the collecting grid lines, so that the paste is printed to form a patterned paste, and the collecting grid lines are obtained after sintering the paste. However, the steel wire on the steel screen will block the ink of the paste, thereby affecting the flatness of the collecting grid lines. Especially when the line width of the collecting grid lines is narrow, the collecting grid lines printed by the steel screen are prone to cause printing defects such as broken grid and ghosting. However, the collecting grid lines with narrow line width can reduce the wet weight of the paste and reduce the shading area, which is beneficial to the cost reduction and efficiency improvement of the solar cell. In other words, the collecting grid lines printed by the steel screen are difficult to reduce the cost and improve the efficiency by narrowing the line width.

[0115] As shown in Figure 1 The high-opening screen 30 can avoid the above-mentioned problems of the steel screen. Specifically, the high-opening screen mainly sets a high-opening printing slot on the metal / alloy screen, and the paste can pass through the printing slot without being blocked by the steel wire, so that the collecting grid lines with narrow line width can be printed while reducing the frequency of printing abnormalities. However, the inventors have found that since the metal screen is usually thin, and the high-opening printing slot usually extends for a certain length, the strength of the high-opening screen 30 at the position corresponding to the high-opening printing slot 31 is weakened. In particular, the longer the length of the high-opening printing slot 31, the worse the structural strength of the high-opening screen 30. However, in order to print continuous collecting grid lines, the high-opening printing slot 31 is continuous and has a relatively long length, and the structural strength of the high-opening screen 30 is poor.

[0116] It should be noted that the high-opening rate in this application refers to an opening rate of 80% to 100%.

[0117] The inventors have found that, referring to Figure 2, by staggering the high opening printing groove 31 into multiple sections, that is, the high opening printing groove 31 is discontinuous, the length of the high opening printing groove 31 can be shortened to reduce the influence of the high opening printing groove on the structural strength of the high opening rate screen 30. However, the discontinuous high opening printing groove 31 printed into multiple sections requires printing a connecting structure at the location of the current collecting grid line in other printing processes to connect the staggered current collecting grid line into a continuous state, that is, it is not possible to print a continuous current collecting grid line in one printing process. And when the front of the solar cell is printed twice, this connecting structure does not form an ohmic contact with the doped layer due to the use of non-burn-through paste, that is, the connecting structure does not have the current collecting function of collecting carriers from the crystalline silicon substrate or the doped layer, and the current collecting effect of the whole current collecting grid line is reduced. And when this connecting structure is printed due to the alignment accuracy of the equipment, it is easy to form an invalid electrical connection with the discontinuous current collecting grid line and affect the transmission of current.

[0118] Based on the above analysis, the printing screen provided by the embodiment of the present application has a printing groove that can be used to print a current collecting grid line. Considering that a too long printing groove will affect the structural strength of the screen body, the reinforcing part of the present application is provided corresponding to the part of the printing groove, that is, the reinforcing part is structurally enhanced at the part of the printing groove to reduce the influence of the printing groove on the structural strength of the screen body. In order to maintain the printing continuity of the printing groove, the reinforcing part of the present application is at least partially hollow. In other words, the paste can be printed through the reinforcing part to connect the connecting structure of the current collecting grid line, which maintains the continuity of the current collecting grid line, is conducive to current collection of the current collecting grid line, and can meet the process and test requirements of energizing the solar cell.

[0119] The technical solutions of the present application will be described below in conjunction with the embodiments and drawings.

[0120] In the first aspect, please refer to Figures 3 to 5 The embodiment of the present application discloses a printing screen 10, which comprises a screen body 11 and a reinforcing part 12.

[0121] The screen body 11 is provided with a printing groove 13 extending along the first direction X, and the printing groove 13 penetrates the screen body 11 along the thickness direction Z of the screen body.

[0122] The reinforcing part 12 is provided at the position of the screen body 11 provided with the printing groove 13, and the reinforcing part 12 is provided corresponding to the part of the printing groove 13. The reinforcing part 12 is at least partially hollow, and the hollow part of the reinforcing part 12 is in communication with the printing groove 13.

[0123] It should be noted that the printing groove 13 extending along the first direction X can be understood as: the printing groove 13 is elongated along the first direction X, that is, the first direction X is the length direction of the printing groove 13.

[0124] The printing groove 13 of the printing screen 10 can be used to print the current collecting grid lines. In view of the influence of the structure strength of the screen body 11 when the printing groove 13 is too long, the reinforcing part 12 of the present application is arranged corresponding to the printing groove 13, that is, the reinforcing part 12 structurally reinforces the screen body 11 at the position of the printing groove 13, so as to reduce the influence of the printing groove 13 on the structure strength of the screen body 11. In order to maintain the printing continuity of the printing groove 13, the reinforcing part 12 of the present application is at least partially hollow. In other words, the paste can be printed to connect to the connecting structure of the current collecting grid lines through the reinforcing part 12, the connecting structure maintains the continuity of the current collecting grid lines, is beneficial to the current collecting of the current collecting grid lines, and can meet the process and test requirements of energizing the solar cell.

[0125] In summary, the printing screen 10 has the advantages of high printing quality and high structure strength, and can print the current collecting grid lines with continuous structure, is beneficial to the current collecting of the current collecting grid lines, and can meet the process and test requirements of energizing the solar cell.

[0126] More specifically, the paste refers to the paste used to print the grid lines of the solar cell, for example, silver paste or silver-aluminum paste, aluminum paste, copper paste or silver-coated copper paste.

[0127] In the embodiment of the present application, the printing groove 13 is multiple, and the multiple printing grooves 13 are arranged at intervals in the second direction Y. Specifically, the number of the printing grooves 13 can be two, three, four, etc., which is not limited in the embodiment of the present application. The multiple printing grooves 13 are used to print the multiple current collecting grid lines arranged at intervals in the second direction Y.

[0128] It should be noted that when the printing groove 13 is multiple, at least one printing groove 13 can be provided with the reinforcing part 12 corresponding to the printing groove 13, so as to structurally reinforce the screen body 11. Of course, as shown in the figure, the present application can also be provided with the reinforcing part 12 corresponding to the printing groove 13 on the multiple printing grooves 13. Figure 3 In addition, as shown in the figure, the present application can also be provided with one reinforcing part 12 corresponding to the multiple printing grooves 13, for example, along the second direction, the reinforcing part 12 can extend from one side of the screen body to the other side of the screen body 11, so that the reinforcing part 12 can pass through the multiple printing grooves 13, and the structure of the screen body 11 is reinforced. Figure 4

[0129] The printing groove and the reinforcing part will be described in detail below.

[0130] It can be understood that the printing groove can be formed on the screen body by means of, for example, laser etching, chemical etching, electroplating, etc., that is, the printing groove has a high opening design on the screen body, and along the thickness direction of the screen body, the printing groove penetrates through both sides of the screen body along the thickness direction, so that the printing groove forms openings on both sides of the screen body in the thickness direction.​

[0131] In view of the fact that the reinforcing portion is mainly for enhancing the structural strength of the screen body at the positions corresponding to the printing slots, based on this, as shown in Figure 3 and Figure 4 , in the embodiments of the present application, the reinforcing portion 12 is arranged corresponding to the part of the printing slot 13 in the first direction X, so that the printing slot 13 has a first opening section 133 and a second opening section 134 in the first direction X, and the reinforcing portion 12 is located between the first opening section 133 and the second opening section 134. It can be understood that the area between the first opening section 133 and the second opening section 134 is reinforced by the reinforcing portion 12, which is equivalent to the reinforcing portion 12 reinforcing the structure of the screen body 11 at the position between the two ends of the printing slot 13, and the reinforcing effect is better.

[0132] In some embodiments, referring to Figure 5 and Figure 6 , in the second direction Y, the reinforcing portion 12 is arranged between the two opposite sides of the printing slot 13. Wherein, the second direction Y intersects the first direction X.

[0133] Since the reason for the decrease in the structural strength of the screen body 11 is the lack of tension between the two opposite sides of the printing slot 13. Then, arranging the reinforcing portion 12 between the two opposite sides of part of the printing slot 13 can effectively enhance the structural strength of the screen body 11. Exemplarily, the reinforcing portion 12 is integrally formed between the two opposite sides of the printing slot 13, and the integrally formed manner makes the integrity between the reinforcing portion 12 and the screen body 11 better, thereby effectively enhancing the structural strength of the screen body 11.

[0134] More specifically, the integrally formed manner of the reinforcing portion 12 can be, for example, electroforming, laser engraving or electroplating. Of course, the reinforcing portion 12 can also be arranged by non-integrally formed fixing methods such as bonding, welding or lamination, etc.

[0135] In the embodiments of the present application, the second direction Y can be perpendicular to the first direction X. Wherein, the perpendicular includes the case that the first direction X is completely perpendicular to the second direction Y, that is, the included angle between the first direction X and the second direction Y is 90°, of course, it also includes the case that the two are approximately perpendicular, for example, the included angle between the first direction X and the second direction Y is 87°, 88°, 89°, 91° or 92°, etc. Of course, as other embodiments, the first direction X and the second direction Y can also be not perpendicular, for example, it can be 85° or 95° and other angles.

[0136] Referring to Figure 5 and Figure 6In some embodiments, the reinforcing portion 12 is arranged between at least one side or both sides in the thickness direction Z of the screen body. The reinforcing portion 12 arranged at least one side in the thickness direction Z of the screen body can be understood as the reinforcing portion 12 arranged at one side or both sides in the thickness direction Z of the screen body. For example Figure 5 When the reinforcing portion 12 is arranged at one side in the thickness direction Z of the screen body, the reinforcing portion 12 is beneficial to expand the space for ink transfer of the printing groove 13 and increase the space for shaping the ink, and a higher grid line can be printed by the reinforcing portion 12. Alternatively, see Figure 6 When the reinforcing portion 12 is arranged between both sides in the thickness direction Z of the screen body, the reinforcing portion 12 at this position is equivalent to reinforcing the screen body 11 from the inside of the screen body 11, which is more beneficial to reduce the impact of the arrangement of the printing groove on the structural strength of the screen body 11.

[0137] In some embodiments, as shown in Figures 7 to 11 The reinforcing portion 12 can include at least one of a comb structure 12a, a honeycomb structure 12b, a grid structure 12c, a ring structure 12d, or a fold line structure 12e. The reinforcing portion 12 includes at least one of the comb structure 12a, the honeycomb structure 12b, the grid structure 12c, the ring structure 12d, or the fold line structure 12e, which can be understood as each reinforcing portion 12 can be any one or a combination of the comb structure 12a, the honeycomb structure 12b, the grid structure 12c, the ring structure 12d, or the fold line structure 12e.

[0138] These structures can provide stronger mechanical structural support to the screen body, and these structures can form a hollow area 122, so that the hollow area 122 projects directly below the corresponding printing groove 13 and the hollow area 122 forms a deeper ink transfer area, thereby forming a connection structure 23 with a higher printing height.

[0139] Further, the reinforcing portion has a plurality of linear sub-structures 121, which are arranged at intervals to form a hollow area 122, or the plurality of linear sub-structures 121 are connected to form a hollow area 122, and the hollow area 122 is in communication with the printing groove 13. The reinforcing portion composed of linear sub-structures 121 has sufficient structural strength to reinforce the screen body, and can form a deeper ink transfer area in the area corresponding to the printing groove 13 and the reinforcing portion 12, which is beneficial to form a connection structure with a higher printing height. Exemplarily, the linear sub-structure 121 can be a metal wire such as a steel wire.

[0140] Of course, the reinforcing portion can also be a film structure, for example, a plurality of hollow holes are formed on the film structure.

[0141] In more detail, as shown in Figure 7As shown, when the reinforcing portion is a comb structure 12a, multiple linear sub-structures 121 are arranged at intervals to form hollow areas 122. As shown in Figure 8 As shown, when the reinforcing portion is a honeycomb structure 12b, multiple linear sub-structures 121 are connected to form hollow areas 122. As shown in Figure 9 As shown, when the reinforcing portion is a mesh structure 12c, multiple linear sub-structures 121 are connected and interwoven to form hollow areas 122. As shown in Figure 10 As shown, when the reinforcing portion is a ring structure 12d, the linear sub-structure 121 is in the shape of a ring, for example, a circular ring, an elliptical ring, or a polygonal ring. In this case, the inner periphery of the linear sub-structure 121 and the space between two linear sub-structures 121 form hollow areas 122. As shown in Figure 11 As shown, when the reinforcing portion is a zigzag structure 12e, multiple linear sub-structures 121 are sequentially connected end to end to form hollow areas 122. Of course, the above is only an example of some reinforcing portions, and embodiments of the present application are not limited thereto.

[0142] Optionally, the area of the cross section of the linear sub-structure 121 is 16 μm 2 ~ 225 μm 2 and any point value within the range, for example, 16 μm 2 , 50 μm 2 , 100 μm 2 , 150 μm 2 or 225 μm 2 . The cross section is a plane formed by the first direction X and the thickness direction Z of the screen body. When the cross section of the linear sub-structure 121 satisfies the area range, the structural strength of the screen body 11 can be effectively enhanced, and the resistance to the paste is small, so that the paste has better passability in the reinforcing portion 12.

[0143] In some embodiments, as shown in Figure 8 , when the reinforcing portion is a honeycomb structure 12b, the honeycomb structure 12b can be arranged between two opposite sides of part of the printing groove 13 in the second direction Y. The honeycomb structure 12b includes multiple honeycomb grids 123, and the inner periphery of each honeycomb grid 123 forms a hollow area 122, which is in communication with the printing groove 13.

[0144] The honeycomb structure 12b has a good effect on the structural reinforcement of the printing groove 13, because the honeycomb structure 12b has good geometric mechanical properties. Moreover, the hollow area 122 in the inner periphery of the honeycomb grid 123 can supply ink to the paste, so that the honeycomb structure 12b takes into account both structural reinforcement and paste ink supply.

[0145] The reinforcing portion will be further described in detail below, taking the comb structure as an example.

[0146] Referring to Figure 12 andFigure 13 In other embodiments, when the reinforcing part 12 is a comb-shaped structure 12a, the comb-shaped 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 area 122 is formed between two adjacent linear substructures 121, the hollow area 122 communicating 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.

[0147] It should be noted that the number of linear substructures 121 in each comb structure 12a can be two, three or four, and this application embodiment does not limit this.

[0148] Furthermore, such as Figure 13 As shown, 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 11 is weaker when the width of the width gradient portion 135 is larger, and the ink passage is worse when the width of the width gradient portion 135 is narrower, 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, 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.

[0149] like Figure 13As shown, preferably, the distance D1 between two adjacent linear substructures 121 is 0.042mm-0.084mm, which can include any value within the range, such as 0.042mm, 0.06mm or 0.084mm. When the distance D1 between two adjacent linear substructures 121 satisfies the above range, the linear substructures 121 are distributed densely enough, the structural reinforcement effect of the comb structure 12a is good, and there is enough distance between the two linear substructures 121 for the slurry to pass through, reducing the influence of the linear substructures 121 on the printing effect.

[0150] Optionally, the linear substructures are at least partially arched in the thickness direction of the screen body. Of course, the linear substructures can also be straight.

[0151] Preferably, the wire diameter of the linear substructures 121 in the comb structure 12a is 6μm-15μm, including any value within the range, such as 6μm, 7μm, 10μm or 15μm. When the linear substructures 121 satisfy the above wire diameter range, the structural strength of the comb structure 12a is higher, and the screen body 11 is mechanically reinforced more strongly, and the linear substructures 121 are also fine enough to reduce the ink amount of the slurry, achieving the effect of reducing slurry consumption while meeting the needs of the grid printing.

[0152] The screen body will be described in detail below.

[0153] It should be noted that the following description is based on the example of the reinforcing portion being a comb structure, but it can be understood that the following description of the screen body also applies to various cases when the reinforcing portion is a honeycomb structure, a grid structure, a ring structure or a polyline structure.

[0154] Optionally, the screen body can be a metal or alloy screen, for example. Figure 14 and Figure 15 As shown, in the present embodiment, the screen body 11 includes a plurality of metal sub-layers, which are stacked in the thickness direction Z of the screen body.

[0155] It can be understood that each metal sub-layer is thinner than the screen body 11, so each metal sub-layer has the advantage of high slotting accuracy, and can be precisely slotted to obtain partial printing slots 13, and then the metal sub-layers are stacked to obtain a screen body 11 with high slotting accuracy. The total thickness of the screen body 11 obtained after the metal sub-layers are stacked is also relatively thick, so that the screen body 11 has a relatively large grid printing height. Since the depth of the printing slot 13 is comparable to the thickness of the screen body 11, a thicker screen body 11 is also conducive to the shaping of the printed grid lines, so that the current collecting grid lines and the connecting structure are printed high enough.

[0156] 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.

[0157] Furthermore, the multiple metal sublayers include a printing shaping layer 111 and a skeleton layer 112. In the paste feeding direction of the screen body 11, the skeleton layer 112 is located in front of the printing shaping layer 111. A reinforcing portion 12 is disposed on the skeleton layer 112. The term "paste feeding direction" refers to the direction in which the paste is transported in the screen body 11. It can be understood that since the skeleton layer 112 is located above the printing shaping layer 111, after the paste enters the screen body 11, it 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 can reduce the influence of the reinforcing portion 12 on the paste shaping, thereby improving the printing quality. Furthermore, the reinforcing portion 12 located on the skeleton layer 112 can prevent the paste in the skeleton layer 112 from being scraped away when the squeegee applies the paste, so that the paste is retained in the skeleton layer 112 as much as possible, thereby allowing the paste in the skeleton layer 112 and the paste in the shaping layer 111 to be cumulatively printed on the surface of the solar cell preform. In general, the height of the slurry printed on the reinforcing section 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 on the reinforcing section 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 on the reinforcing section 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 on the reinforcing section 12 deviates slightly from the sum of the thicknesses of the skeleton layer 112 and the printed shaping layer 111.

[0158] Optionally, 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 conducive to improving the service life of the screen body 11.

[0159] More in detail, Figure 14 In this design, the dimension of the reinforcing part 12 in the thickness direction Z of the screen body can be the same as or different from the thickness of the skeleton layer 112. The reinforcing part 12 can be located at any position in the thickness direction of the skeleton layer 112.

[0160] 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.

[0161] Optionally, the thickness T1 of the printing shaping layer 111 is 2 μm-20 μm, and includes any value within the thickness range, for example, 2 μm, 5 μm, 10 μm, 15 μm or 20 μm. When the printing shaping layer 111 satisfies the above thickness range, the printing shaping layer 111 has a better slurry shaping effect, and has a higher slotting accuracy and a higher printed grid line height.

[0162] In the embodiment of the present application, the material of the skeleton layer 112 is nickel alloy, for example, nickel steel. The skeleton layer 112 made of nickel alloy has excellent corrosion resistance and mechanical properties, such as good ductility and toughness, which is suitable for the use scenario of the printing screen 10. Of course, the material of the skeleton layer 112 can also be other metal materials.

[0163] Optionally, the thickness T2 of the skeleton layer 112 is 2 μm-20 μm, and includes any value within the thickness range, for example, 2 μm, 5 μm, 10 μm, 15 μm or 20 μm. When the skeleton layer 112 satisfies the above thickness range, the skeleton layer 112 has a better structural strength, and has a higher slotting accuracy and a higher printed grid line height.

[0164] Further, the plurality of metal sub-layers further include a bonding layer 113, which is connected between the skeleton layer 112 and the printing shaping layer 111 in the thickness direction Z of the screen body. The bonding layer 113 is used to enhance the bonding force between the skeleton layer 112 and the printing shaping layer 111, so as to improve the overall strength of the screen body 11.

[0165] Preferably, the material of the bonding layer 113 is selected from at least one of nickel or copper. Nickel and copper are both metals that can be used to enhance the adhesion of nickel alloy film layers, and the materials of the skeleton layer 112 and the printing shaping layer 111 are 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 printing shaping layer 111, so that the skeleton layer 112 and the printing shaping layer 111 have a better bonding effect.

[0166] Optionally, the thickness T3 of the bonding layer 113 is 70 nm-80 nm, and includes any value within the thickness range, for example, 70 nm, 75 nm or 80 nm. When the bonding layer 113 satisfies the above thickness range, the bonding layer 113 can effectively enhance the connection strength between the skeleton layer 112 and the printing shaping layer 111.

[0167] The printing slot is described in detail below.

[0168] It should be noted that the following description is based on the example that the reinforcing part is a comb structure, but it can be understood that the following description of the printing groove is also applicable to various cases when the reinforcing part is a honeycomb structure, a grid structure, a ring structure, or a polyline structure.

[0169] In some embodiments, referring back to Figure 12 In the first direction X, the portion of the printing groove 13 that is offset from the reinforcing part 12 is a first printing part 131, and the opening rate of the first printing part 131 is 80% to 100% and includes any point value within the range, such as 80%, 90%, or 100%, and more preferably 100%, that is, the first printing part 131 is a high opening. The first printing part 131 has better slurry passability because there is no object such as a steel wire to block it, and it can print a relatively narrow current collecting grid line with fewer printing abnormalities. When the first printing part 131 has a full opening rate of 100%, there is no steel wire at the first printing part 131 to strengthen the mechanical support strength of the printing screen 10; when the first printing part 131 has a high opening rate of 80% to 100% (excluding the endpoint of 100%), the first printing part 131 is correspondingly distributed with sparse steel wires to strengthen the mechanical support strength of the printing screen 10. Compared with the aforementioned first printing part 131 with a 100% opening rate, although the sparse distribution of steel wires will cause blockage to the infiltrating slurry and increase the unevenness of the grid line printed by the first printing part 131, the impact is small because the steel wires are distributed sparsely, and the sparse distribution of steel wires can also increase the mechanical support strength of the printing screen 10. Therefore, the screen with sparse distribution of steel wires at the first printing part 131 has a smaller smoothness factor of the first connecting structure printed therefrom.

[0170] On the other hand, the opening rate of the reinforcing part 12 is 30% to 70%. When the reinforcing part 12 satisfies the opening rate range, it indicates that the reinforcing part 12 can provide an area-appropriate mechanical support part for the printing screen 10, thereby effectively enhancing the structural strength of the screen body 11, and at the same time, it also indicates that the reinforcing part 12 has more hollow regions 122, and the slurry has good passability in the reinforcing part 12, which is beneficial to the infiltration of the slurry and the printing and forming on the surface of the solar cell.

[0171] In some embodiments, continuing to refer to Figure 12 The plurality of reinforcing parts 12 are arranged corresponding to the same printing groove 13, and the plurality of reinforcing parts 12 are arranged at intervals in the first direction X. In order to continuously print a current collecting grid line that is long enough, the length of the printing groove 13 in the first direction X also needs to be relatively long. By arranging a plurality of reinforcing parts 12, that is, arranging a reinforcing part 12 at 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 as long as possible to print a current collecting grid line that is long enough.

[0172] Preferably, in the first direction X, the size of the screen body 11 is D2, the distance between two adjacent reinforcing portions 12 is D3, D3 / D2 = 1%~20% and includes any point value in the range of the ratio, for example, 1%, 5%, 10%, 15% or 20%. When the printing screen 10 meets the above range of ratio, the distribution density of the reinforcing portion 12 on the screen body is moderate, and there is enough distribution density to enhance, which can not only ensure that the screen body 11 has high overall structural strength, but also is conducive to the pulp feeding and printing of the printing slot 13 because the number of positions of the printing slot 13 blocked by the reinforcing portion 12 is less. The distance D3 between the two adjacent reinforcing portions 12 refers to the distance between the centers of the two adjacent reinforcing portions 12.

[0173] Optionally, in the first direction X, the size D2 of the screen body 11 is 166mm~230mm and includes any point value in the size range, for example, 166mm, 182mm, 210mm or 230mm, and the distance D3 between two adjacent reinforcing portions 12 is 3mm~50mm and includes any point value in the distance range, for example, 3mm, 10mm, 20mm or 50mm. When the size D2 of the screen body 11 and the distance D3 between two adjacent reinforcing portions 12 meet the above range, the distribution density of the reinforcing portion 12 is moderate, the structural strength of the screen body 11 is high, and the number of positions of the printing slot 13 blocked by the reinforcing portion 12 is less, which is conducive to the pulp feeding and printing of the printing slot 13.

[0174] Optionally, among two adjacent reinforcing portions 12 on the same printing slot 13, one of the reinforcing portions 12 is configured as a connecting structure for printing at the intersection of the current collecting grid line and the bus grid line, and the other reinforcing portion 12 is configured as a connecting structure for printing staggered with the bus grid line. The position of the reinforcing portion will be illustrated respectively below.

[0175] Please refer to Figures 12 to 15 , the size of the first printing portion 131 in the second direction Y is the width.

[0176] For details, please refer to Figure 15The width of the first printing part 131 in the printing shaping layer 111 is W1, and the width of the first printing part 131 in the skeleton layer 112 is W2; wherein W2:W1=(13-23):1, which includes any point value in the ratio range, for example, 13:1, 15:1, 20:1 or 23:1. When W2:W1 meets the above ratio range, the scraper can extend into the part of the first printing part 131 in the skeleton layer 112 under the condition of stress deformation, and then scrape off the slurry of the first printing part 131 in the skeleton layer 112. At the same time, since the ratio of W2:W1 is large enough, it can provide sufficient slurry source for the slurry in the printing shaping layer 111, and improve the infiltration of the slurry in the printing shaping layer 111.

[0177] It should be noted that the slurry height printed by the first printing part 131 is approximately the same as the thickness of the printing shaping layer 111, which can be explained as follows: the slurry height printed by the first printing part 131 is the same as the thickness of the printing shaping layer 111, or the slurry height printed by the first printing part 131 is slightly different from the thickness of the printing shaping layer 111.

[0178] In combination with the above analysis, the slurry height printed by the reinforcing part 12 is approximately the same as the sum of the thicknesses of the skeleton layer 112 and the printing shaping layer 111. The slurry height printed by the first printing part 131 is the same as the thickness of the printing shaping layer 111. In the present application, the first printing part 131 is configured to print the collector grid line of the solar cell. The reinforcing part 12 is configured to print the connecting structure connected to the collector grid line. Therefore, it can be understood that the printing screen of the present application can prepare the connecting structure with a maximum height higher than the collector grid line by one-time printing.

[0179] Preferably, the width W1 of the first printing part 131 in the printing shaping layer 111 is 3-15 μm, and includes any point value in the width range, for example, 3 μm, 5 μm, 10 μm or 15 μm. When the width W1 of the first printing part 131 in the printing shaping layer 111 meets the above width range, it can be used to print the collector grid line with a narrower line width to achieve cost reduction and efficiency improvement, and also has a lower light shielding rate to improve the conversion efficiency of the solar cell.

[0180] 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. Preferably, the width W2 of the first printed portion 131 in the skeleton layer 112 is 100μm to 150μm and any value within this width range, such as 100μm, 120μm, 140μm, or 150μm. When the width W2 of the first printed portion 131 in the skeleton layer 112 meets the above-mentioned width range, the structural strength of the skeleton layer 112 is high. In addition, the difference between the width W2 and the width W1 is large enough that less paste from the first printed portion 131 accumulates on the paste in the printed shaping layer 111, so that the height of the current collector line printed by the first printed portion 131 is mainly determined by the thickness of the printed shaping 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.

[0181] Furthermore, such as Figure 12 and Figure 14 As shown, the portion of the printing groove 13 and the reinforcing part 12 that is disposed in the skeleton layer 112 is configured as a width-narrowing part 136. The width-narrowing part 136 has a width in the second direction, and the width of the width-narrowing part 136 narrows along the feeding direction of the screen body 11.

[0182] 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.

[0183] 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.

[0184] The reinforcing portion 12 includes a first reinforcing portion 12f configured as a first connecting structure printedly connected to the current collecting grid lines, the first connecting structure being arranged at the intersection of the current collecting grid lines and the bus grid lines;

[0185] And / or, the reinforcing portion 12 includes a second reinforcing portion 12g, the first reinforcing portion 12f is configured as a second connecting structure printedly connected to the current collecting grid lines, in the first direction X, the second connecting structure is staggered with the bus grid lines and both ends of the second connecting structure are connected to the same current collecting grid line.

[0186] In more detail, the reinforcing portion is one or more. When the reinforcing portion is one, the reinforcing portion is the first reinforcing portion or the second reinforcing portion. When the reinforcing portion is more than one, the plurality of reinforcing portions can all be the first reinforcing portion; or, the plurality of reinforcing portions are all the second reinforcing portion; or, the plurality of reinforcing portions 12 include the first reinforcing portion 12f and the second reinforcing portion 12g.

[0187] It should be noted that the first connecting structure is also called a lap joint structure, also known as “centipede grid line” or “centipede foot”. The second connecting structure is also called a connecting grid line. In the field, the lap joint structure and the connecting grid line can be wider than the current collecting grid line, and accordingly, the part of the printing slot 13 corresponding to the first reinforcing portion 12f and the second reinforcing portion 12g can be wider than the first printing portion 131 described above in the first direction X. Since the first reinforcing portion 12f and the second reinforcing portion 12g can block the flow of paste, the first reinforcing portion f and the second reinforcing portion g just use the wider part of the printing slot 13 for paste inking, and the paste passability at this position is also better. The design can reduce the influence of the first reinforcing portion f and the second reinforcing portion g on the paste passability, and the printing quality is also better.

[0188] The length and width of the part of the printing slot corresponding to the first reinforcing portion and the second reinforcing portion will be described in detail below.

[0189] As shown in Figure 12 and Figure 16 When the reinforcing portion 12 includes the first reinforcing portion 12f, the part of the printing slot 13 corresponding to the first reinforcing portion 12f is the second printing portion 132a, and the length and width of the second printing portion 132a are as follows:

[0190] If the length L2 of the second printing part 132a in the first direction X is less than 0.3 mm, the length of the first connecting structure printed by the second printing part 132a is insufficient, the welding performance is poor, and the length of the first reinforcing part 12f in the first direction X is also small, which leads to a decrease in the service life of the printing screen 10. If the length L2 of the second printing part 132a in the first direction X is greater than 2 mm, the area of the first connecting structure printed by the second printing part 132a is large, and the efficiency of the solar cell decreases. Therefore, in the embodiment, the length L2 of the second printing part 132a in the first direction X is 0.3 mm to 2 mm, and any point value within the length range, for example, 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 part 132a satisfies the above length range, the requirement for welding alignment accuracy can be reduced, and the yield of welding is improved. Moreover, the length of the first reinforcing part 12f in the first direction X is also long, which is beneficial to improve the service life of the printing screen 10.

[0191] The size of the second printing part 132a in the second direction Y is the width. In the first direction X, the width of the second printing part 132a narrows from the middle to both ends. If the width W4 of the widest part of the second printing part 132a is less than 10 μm, the first connecting structure printed by the second printing part 132a is narrow, the welding performance is poor, and the size of the first reinforcing part 12f is also small, which leads to a decrease in the service life of the printing screen 10. If the width W4 of the widest part of the second printing part 132a is greater than 100 μm, the first connecting structure printed by the second printing part 132a is too wide, and the light shielding area increases. Therefore, in the embodiment, the width W4 of the widest part of the second printing part 132a is 10 μm to 100 μm, and any point value within the width range, for example, 10 μm, 50 μm, or 100 μm. When the widest part of the second printing part 132a satisfies the above width range, the first connecting structure printed by the second printing part 132a can provide a higher welding area for welding, and the yield of the solder strip is improved. Moreover, the size of the first reinforcing part 12f is also large, which is beneficial to improve the service life of the printing screen 10.

[0192] 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.

[0193] like Figure 16 As shown, 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, and the length and width of the third printing part 132b are as follows:

[0194] 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.

[0195] If the width W6 of the second printing part 132a in the second direction Y is less than 8 μm, the paste passing property in the second printing part 132a is poor, the printing abnormality is increased, and the size of the second reinforcing part 12g is also small, which leads to the service life of the printing screen 10 being reduced. If the width W6 of the second printing part 132a in the second direction Y is greater than 100 μm, the second connecting structure printed by the second printing part 132a is also wide, and the light shielding area is large, which is not conducive to improving the conversion efficiency of the solar cell. Therefore, in the embodiment of the present application, the width W6 of the second printing part 132a in the second direction Y is 8 μm-100 μm and includes any point value in the range, for example, 8 μm, 50 μm or 100 μm. When the second printing part 132a satisfies the above width range, on the one hand, the paste passing property of the second printing part 132a is good, the printing abnormality is less, and the size of the second reinforcing part 12g is large enough, which is conducive to improving the service life of the printing screen 10. On the other hand, the width of the second connecting structure 23b printed by the second printing part 132a is moderate, which is also conducive to the current collector grid line 22 collecting carriers from the silicon substrate 211.

[0196] In the second aspect, referring back to Figure 12 The embodiment of the present application discloses a printing screen 10, which comprises a screen body 11, and the screen body 11 is provided with a printing groove 13 extending in a first direction X, and the printing groove 13 penetrates through the thickness direction Z of the screen body. In the first direction X, the printing groove 13 has a first printing part 131 and a second printing part 132a connected in sequence, the first printing part 131 is a high opening, and the second printing part 132a is provided with a hollow first reinforcing part 12f. In the second direction Y, the first reinforcing part 12f is at least partially connected between two opposite sides of the second printing part 132a. And / or, in the first direction X, the printing groove 13 has a first printing part 131 and a third printing part 132b connected in sequence, the first printing part 131 is a high opening with an opening rate of 80%-100%, and the third printing part 132b is provided with a hollow second reinforcing part 12g; in the second direction Y, the second reinforcing part 12g is at least partially connected between two opposite sides of the third printing part 132b.

[0197] The first printing part 131 of the printing screen 10 is a high opening. The first printing part 131 with high opening has a high opening rate, and the resistance to ink blocking is low. This feature makes the first printing part 131 with high opening suitable for printing a current collecting grid line with a narrow line width and high regularity, and the printing abnormality is also low. Considering that the first printing part 131 with high opening lacks steel wire pulling or the distribution of steel wires providing pulling force is sparse, the printing slot 13 of the present application further has a second printing part 132a connected with the first printing part 131, and the second printing part 132a is provided with a first reinforcing part 12f in a hollow structure. In the second direction Y, the first reinforcing part 12f is at least partially connected between the two opposite sides of the second printing part 132a. The first reinforcing part 12f can provide pulling force for the overall mechanical strength of the printing screen 10, so that the structural strength of the printing screen 10 is enhanced. The first reinforcing part 12f in the hollow structure can also pass the slurry, so as to print a current collecting grid line with a continuous structure, which is beneficial to current collection of the current collecting grid line and can meet the process and test requirements of energizing the solar cell.

[0198] And / or, the printing slot 13 of the present application further has a second printing part 132b connected with the first printing part 131, and the second printing part 132b is provided with a second reinforcing part 12g in a hollow structure. In the second direction Y, the second reinforcing part 12g is at least partially connected between the two opposite sides of the second printing part 132b. The second reinforcing part 12g plays a pulling role, so that the structural strength of the printing screen 10 is enhanced. The second reinforcing part 12g in the hollow structure can also pass the slurry, so as to print a current collecting grid line with a continuous structure, which is beneficial to current collection of the current collecting grid line and can meet the process and test requirements of energizing the solar cell.

[0199] In summary, the printing screen 10 has the advantages of high printing quality and high structural strength, and can print a current collecting grid line with a continuous structure, which is beneficial to current collection of the current collecting grid line and can meet the process and test requirements of energizing the solar cell.

[0200] In a third aspect, the present application discloses a manufacturing method of the printing screen as described in the first aspect or the second aspect, comprising the following steps:

[0201] Providing a screen semi-finished product; wherein the screen semi-finished product has a printing slot;

[0202] Manufacturing a reinforcing part on the printing slot.

[0203] The manufacturing method strengthens the structure strength of the printing screen by manufacturing the reinforcing part on the printing groove, and the reinforcing part can be used for passing the slurry, so that the structure continuous current collecting grid line can be printed, which is beneficial to current collection of the current collecting grid line and can meet the process and test requirements of energizing the solar cell.

[0204] In the present application, the screen half-finished product can be one or more metal sub-layers. The printing groove on the screen half-finished product can be a partial printing groove or a complete printing groove.

[0205] More specifically, the manufacturing method comprises the following steps:

[0206] Manufacturing the insulating layer: manufacturing the patterned insulating layer on the conductive substrate; wherein the pattern of the insulating layer is the same as the pattern of the printing groove;

[0207] Manufacturing the printing shaping layer: electroforming the conductive substrate with the insulating layer, the insulating layer is electroformed outside the patterned area of the insulating layer to form the printing shaping layer, and the patterned area of the insulating layer is not electroformed to form the partial printing groove;

[0208] Manufacturing the bonding layer: manufacturing the bonding layer on the surface of the printing shaping layer to obtain the screen half-finished product;

[0209] Manufacturing the skeleton layer and the reinforcing part: placing the conductive mold corresponding to the partial printing groove on the side of the bonding layer away from the printing shaping layer, the conductive mold is the same as the pattern of the reinforcing part, electroforming the screen half-finished product, electroforming outside the patterned area of the insulating layer to form the skeleton layer, electroforming on the conductive mold to obtain the reinforcing part integrated with the skeleton layer, not electroforming in the patterned area of the insulating layer to form the remaining printing groove, and removing the insulating layer after electroforming to obtain the printing screen.

[0210] The above manufacturing method is used to manufacture the printing shaping layer and the bonding layer first to obtain the screen half-finished product. Considering that the printing groove of the screen half-finished product is also filled with the insulating layer, and the reinforcing part needs to be arranged corresponding to the partial printing groove, and it is difficult to realize electroforming on the insulating layer. On this basis, the conductive mold corresponding to the partial printing groove is placed on the side of the bonding layer away from the printing shaping layer. It can be understood that the conductive mold enables the local area of the surface of the insulating layer to be electroformed. Further, the reinforcing part integrated with the skeleton layer is obtained after electroforming on the conductive mold. The manufacturing method can manufacture the reinforcing part integrated with the skeleton layer while manufacturing the high-opening printing groove, and the obtained printing screen has the advantages of high printing quality and high structure strength.

[0211] Of course, the reinforcing part can also be integrally formed on the screen printing half-finished product by electroplating, laser engraving or etching, etc. In addition, the reinforcing part can also be made on the screen printing half-finished product by non-integrally forming methods such as pasting, welding and laminating, etc.

[0212] In a fourth aspect, as shown by Figures 17 to 20 The embodiments of the present application disclose a solar cell 20, which comprises a solar cell pre-product 21, a current collecting grid line 22 and connecting structures 23a and 23b. The current collecting grid line 22 is arranged on the surface of the solar cell pre-product 21 and extends along a first direction X. The connecting structures 23a and 23b are arranged on the surface of the solar cell pre-product 21 and connected to the current collecting grid line 22. In the thickness direction of the solar cell pre-product 21, the maximum height of the connecting structures 23a and 23b is greater than the height of the current collecting grid line 22.

[0213] In the embodiments of the present application, the higher connecting structures 23a and 23b can make the cross-sectional area of the connecting structures 23a and 23b larger, and the resistance of the connecting structures 23a and 23b smaller, which is beneficial to improve the transmission capacity of the current collected by the current collecting grid line.

[0214] It should be noted that in the present application, the height measurement starting point of the connecting structures 23a and 23b and the current collecting grid line 22 is the surface of the solar cell pre-product 21, specifically the surface of the first functional film 213. In addition, in the present application, because there is a transition area between the current collecting grid line 22 and the connecting structures 23a and 23b, the height of the transition area gradually transitions from the height of the current collecting grid line 22 to the maximum height of the connecting structures 23a and 23b. As for the testing method of the "maximum height", exemplarily, one of the testing methods of the "maximum height" of the connecting structures 23a and 23b is as follows: a 3D microscope is used at 50 times magnification or other magnification, the height profile is selected based on the width center line of the connecting structures 23a and 23b, and the height curve is measured based on the height profile, and the height value is derived from the height curve, such as 1024 height point values are derived in the present application. It should be noted that according to the system settings of different models of 3D microscopes, any number of height point values can be derived; in order to reduce the influence of abnormal data points on the test, the present application needs to eliminate abnormal height point values, wherein the abnormal data point is defined as the height data point value that exceeds 30% of the average value of the height point values, for example: assuming that the average value of 1024 height point values is X ave , the abnormal data point is X i , when |X i -X ave | / X ave > 30%, the height data point value belongs to the abnormal height point value in the present application.

[0215] It can be understood that the data points for testing the maximum height are not limited to 1024 points, and other test selected numbers can also be used, and the embodiments of the present application are not limited thereto. In the present application, the maximum height of the connecting structure 23a, 23b is defined, and the coordinate points of the height of the connecting structure 23a, 23b are also cleaned to abnormal data points, which can reasonably reflect the technical concept of the present application.

[0216] In some embodiments, with reference to Figure 17 The solar cell 20 further includes a busbar 24 extending along the second direction Y.

[0217] The connecting structure 23a, 23b includes a first connecting structure 23a arranged at the intersection of the current collecting grid line 22 and the busbar 24.

[0218] The connecting structure 23a, 23b includes a second connecting structure 23b staggered with the busbar 24 in the first direction X, and both ends of the second connecting structure 23b are connected to the current collecting grid line 22.

[0219] It should be noted that the connecting structure 23a, 23b can be multiple, and the multiple connecting structures 23a, 23b include the first connecting structure 23a and the second connecting structure 23b.

[0220] In more detail, the first connecting structure 23a is the above-mentioned centipede foot grid line. Exemplarily, the centipede foot grid line can extend in the same direction as the current collecting grid line 22, the line width of the widest part of the centipede foot grid line can be wider than that of the current collecting grid line 22, and the centipede foot grid line can be a width gradient structure. The first connecting structure 23a contacts the solder strip during the welding process of the busbar 24, and the higher first connecting structure 23a can provide more grid line metal for the etching silver reaction during welding, further reducing the phenomenon of broken grid lines of the current collecting grid line 22 caused by etching silver reaction.

[0221] The second connecting structure 23b is the above-mentioned connecting grid line, which can extend in the same direction as the current collecting grid line 22 and be connected to the current collecting grid line 22 at both ends, so that the current collecting grid line 22 is continuous. In more detail, the connecting grid line can be a wider grid line than the current collecting grid line, of course, the connecting grid line can also be a grid line with the same or slightly smaller line width as the current collecting grid line; the pattern of the connecting grid line can be a rectangle, a diamond, or various patterns, and the embodiments of the present application are not limited thereto.

[0222] 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.

[0223] 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.

[0224] The collector grid and the first connection structure are described in detail below.

[0225] In some specific embodiments, such as Figure 18 , Figure 20 , Figure 21 and Figure 22 As shown, Figure 21 As can be seen, the first connection structure 23a is higher in morphology than the collector grid line 22. Combined with... Figure 22 , Figure 22 (a) and (b) are cross-sectional profile views of the collector grid line 22 and the first connection structure 23a, respectively. Figure 22 As can be seen in (a), the height of the first connection structure is 9.24 μm. Figure 22 As can be seen in (b), the height of the collector grid line is 5.428 μm. Therefore, it can be concluded that the first connection structure 23a, which is printed in one pass using a printing screen in this application, is taller than the collector grid line 22.

[0226] Refer to the return Figure 20As shown, the maximum height of the first connecting structure 23a is H2, and the height of the current collecting grid line 22 is H3. H3 / H2 = 20%~90% and includes any point value in the range of the proportion, for example, 20%, 30%, 60%, or 90%. When the first connecting structure 23a and the current collecting grid line 22 satisfy the above proportion, on the one hand, the first connecting structure 23a is not too high to cause the wet weight of the paste to be too high during printing, and on the other hand, the first connecting structure 23a has sufficient height to provide sufficient conductive metal (such as silver grid lines formed after sintering of silver paste) for the welding of the first connecting structure 23a and the tin-based alloy on the surface of the solder strip, thereby forming a conductive interconnection structure between the busbar and the solder strip between the tin-based alloy and the conductive metal, reducing the grid breakage phenomenon after welding of the current collecting grid line 22; if the height of the first connecting structure 23a is low (such as less than 6 μm), it is not possible to provide sufficient conductive metal for the welding of the first connecting structure 23a and the tin-based alloy on the surface of the solder strip, which will cause the metal on the grid line at the welding site to be completely reacted by the tin-based alloy, and the grid line at the welding site and the solder strip connection site will be misaligned, so the carriers collected by the current collecting grid line cannot be successfully transmitted to the solder strip.

[0227] Optionally, the maximum height H2 of the first connecting structure 23a is 3.5 μm~15 μm and includes any point value in the height range, for example, 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 connecting structure 23a satisfies the above height range, the first connecting structure 23a itself has a high height, which can provide sufficient conductive metal (such as silver grid lines formed after sintering of silver paste) for the welding of the first connecting structure 23a and the tin-based alloy on the surface of the solder strip, thereby forming a conductive interconnection structure between the busbar and the solder strip between the tin-based alloy and the conductive metal, reducing the grid breakage phenomenon after welding of the current collecting grid line 22; if the height of the first connecting structure 23a is low (such as less than 3.5 μm), it is not possible to provide sufficient conductive metal for the welding of the first connecting structure 23a and the tin-based alloy on the surface of the solder strip, which will cause the metal on the grid line at the welding site to be completely reacted by the tin-based alloy, and the grid line at the welding site and the solder strip connection site will be misaligned, so the carriers collected by the current collecting grid line cannot be successfully transmitted to the solder strip.

[0228] It can be understood that when the current collecting grid lines with a narrow width (for example, less than 20 μm) are prepared, if the height of the current collecting grid line 22 is less than 3.5 μm, the cross-sectional area of the current collecting grid line 22 is small, the resistance is large, and the transmission of the current collecting grid line to the current is not good. In addition, when the current collecting grid line with a narrow width is prepared, the printing defects such as virtual printing and broken grid caused by the printing precision of the screen printing plate are prone to occur. If the height of the current collecting grid line 22 is greater than 15 μm, the silver consumption of the current collecting grid line 22 is large, and the manufacturing cost of the solar cell is not reduced. The height H3 of the current collecting grid line 22 is 3 μm to 10 μm and includes any point value in the height range, for example, 3 μm, 5 μm, 6 μm, 8 μm or 10 μm. When the current collecting grid line 22 meets the above height range, the current collecting grid line 22 has low silver consumption and low resistance, and can form a large enough height difference with the connecting structure 23a.

[0229] In the embodiment of the present application, the length L4 of the first connecting structure 23a in the first direction X is 0.5 mm to 2 mm and includes any point value in the length range, for example, 0.5 mm, 1 mm or 2 mm. When the first connecting structure 23a meets the above length range, the welding failure 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 of the widest part of the first connecting structure 23a is 10 μm to 100 μm and includes any point value in the width range, for example, 10 μm, 50 μm or 100 μm, and the width W8 of the narrowest part of the first connecting structure 23a is 5 μm to 60 μm and includes any point value in the width range, for example, 5 μm, 30 μm or 60 μm. 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.

[0230] The second connecting structure will be described in detail below.

[0231] In other specific embodiments, as shown in Figure 19 and Figure 22 , wherein Figure 22 (c) is a cross-sectional profile view of the second connecting structure 23b, Figure 22 , the height of the current collecting grid line 22 is 5.428 μm, and in Figure 22 , the second connecting structure 23b is 9.078 μm. It can be known that the second connecting structure 23b printed by the printing screen plate once in the present application is higher than the current collecting grid line 22.

[0232] Optionally, the maximum height H4 of the second connection structure 23b is 2μm to 12μm, or 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.

[0233] Optionally, 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.

[0234] More preferably, the width W9 of the second connection structure 23b is 8μm to 100μm and includes any value within this width range, such as 8μm, 50μm, or 100μm. 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, and the resistance is low.

[0235] The collector grid is described in detail below.

[0236] In some preferred embodiments, such as Figure 19 As shown, the width W10 of the collector grid line 22 is 5μm to 20μm and includes any value within this width range, such as 5μm, 15μm, or 20μm. The collector grid line 22 with this width range can reduce paste consumption and reduce costs, and also has a lower shading area, which is beneficial to the cost reduction and efficiency improvement of the solar cell 20.

[0237] More preferably, the gate line smoothing factor of the collector gate line 22 is smaller than the gate line smoothing factor of the connecting structures 23a and 23b. Optionally, the gate line smoothing factor of the collector gate line 22 is <1; and / or, the gate line smoothing factor of the connecting structures 23a and 23b is 1 to 8.

[0238] The specific definition of the grid line smoothness factor is as follows: the height profile of the auxiliary grid 221 is measured by using a 3D microscope at any magnification (for example, at 50 times), and based on the height profile, a height curve is measured, the height curve is derived into height coordinate values, for example, 1024 height coordinate point values are derived in the present application, and the variance concept in mathematical statistics of the 1024 height point values is calculated, and the variance is used to represent the fluctuation size of the height of the auxiliary grid 221, that is, the grid line smoothness factor of the present application. It should be noted that according to the system settings of different models of 3D microscopes, any number of height point values can be derived; in order to reduce the error influence of abnormal data points on the calculation of the grid line smoothness factor, the present application needs to eliminate abnormal height point values, wherein the abnormal data points are defined as height data points whose values are 30% higher than the average value of the height point values, for example: assuming that the average value of the 1024 height point values is X ave , the abnormal data points are X i , when |X i -X ave | / X ave > 30%, the height point value is the abnormal height point value of the present application. It can be understood that the smaller the grid line smoothness factor is, the better the smoothness of the grid line is, and the better the current transmission capacity of the grid line is.

[0239] That is, the current collecting grid line 22 can have a smaller smoothness, and the height profile curve of the current collecting grid line 22 is relatively smooth, so that the resistance loss of the current collecting grid line 22 under the unit weight of the grid line metal material is also smaller, thereby improving the current transmission capacity of the solar cell 20.

[0240] It should be noted that the solar cell preform 21 refers to the semi-finished product of the solar cell 20, for example, the semi-finished product obtained after the front and back surface film coating process of the solar cell.

[0241] In some embodiments, referring to Figure 20 , the solar cell preform 21 includes a silicon substrate 211, a doped layer 212, and a first functional film 213, the doped layer 212 and the first functional film 213 are arranged on the surface of the silicon substrate 211 in a direction away from the silicon substrate 211.

[0242] The connection structures 23a and 23b and the current collecting grid line 22 are all arranged on the first functional film 213 and penetrate the first functional film 213 to be in ohmic contact with the doped layer 212.

[0243] It can be understood that the connection structure 23a, 23b and the collector grid line 22 can be printed by using the same printing screen. Accordingly, the connection structure 23a, 23b and the collector grid line 22 use the same paste. Specifically, the paste uses glass frit, which burns through the first functional film and forms ohmic contact with the doped layer when sintered. That is, like the collector grid line 22, the connection structure 23a, 23b also burns through the first functional film and forms ohmic structure with the doped layer, and the connection structure 23a, 23b can collect current from the doped layer to improve the overall current collection effect of the solar cell 20, which is beneficial to the efficiency of the solar cell 20.

[0244] For example, the doped layer 212 is a diffusion layer or a first doped polysilicon layer, for example, a boron diffusion layer or a phosphorus diffusion layer, and the first doped polysilicon layer can be N-type or P-type. The first functional film 213 is a passivation film and / or an anti-reflection film, and 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 the embodiments of the present application. The silicon substrate 211 can be an N-type silicon substrate or a P-type silicon substrate, which is not limited in the embodiments of the present application.

[0245] More specifically, the solar cell 20 can be a passivated contact solar cell or a heterojunction solar cell, which is not limited in the embodiments of the present application. 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, for example, the front side or the back side of the silicon substrate 211. In addition, it should be noted that although the front side and the back side of the silicon substrate 211 are flat in the drawings, the front side and / or the back side of the silicon substrate 211 can also be textured. Further, the solar cell preform 21 further comprises an interface passivation layer 214, a second doped polysilicon layer 215, and a second functional film 216, which are stacked in sequence on the side of the silicon substrate 211 opposite to the doped layer 212 in a direction away from the silicon substrate 211.

[0246] In more detail, the material of the interface passivation layer 214 can include a plurality of dielectric materials, such as at least one of silicon oxide, magnesium fluoride, amorphous silicon, hydrogenated amorphous silicon, polysilicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, or titanium oxide. In particular, the interface passivation layer 214 can be composed of a silicon oxide layer containing silicon oxide. This is because the silicon oxide layer has excellent passivation performance, can minimize the recombination loss of the minority carriers on the surface of the silicon substrate 211, and is a thin film with excellent durability to subsequent high-temperature processes. The interface passivation layer 214, as a potential barrier for electrons and holes, can be combined with the second doped polysilicon layer 215 to prevent the passage of minority carriers. The interface passivation layer 214 can also have a pinhole channel effect, allowing the free movement of carriers within the solar cell 20, producing selective passage of majority carriers through the second doped polysilicon layer 215, which is beneficial to reducing the recombination loss of minority carriers. In addition, the interface passivation layer 214 can act as a diffusion barrier to prevent the diffusion of dopants from the second doped polysilicon layer 215 into the silicon substrate 211.

[0247] 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 should be opposite to that of the doped layer. The second functional film 216 is, for example, a passivation film and / or an anti-reflection film. In more detail, the material of the second functional film 216 can be silicon nitride, silicon oxide, silicon oxynitride, or aluminum oxide, etc., which is not limited in the embodiments of the present application.

[0248] In a fifth aspect, as shown in Figure 23 The present application discloses a photovoltaic module, which includes a plurality of solar cells 20 connected in series and / or parallel, at least one of the solar cells 20 being printed by a printing screen plate as described in the first aspect or the second aspect; or, at least one of the solar cells 20 being printed by a printing screen plate manufactured by the manufacturing method as described in the third aspect; or, at least one of the solar cells 20 being the solar cell 20 as described in the fourth aspect.

[0249] For example, two solar cells 20 are connected in series and / or parallel by an electrical connector 40. The electrical connector 40 can be a solder strip.

[0250] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A printing screen, characterized in that The screen printing plate comprises: a screen body, wherein a printing groove extending along a first direction is arranged on the screen body, and the printing groove penetrates through the screen body along the thickness direction of the screen body; a reinforcing part arranged at the position of the screen body where the printing groove is arranged, wherein the reinforcing part is arranged corresponding to the part of the printing groove, the reinforcing part is at least partially hollow, and the hollow part of the reinforcing part is communicated with the printing groove. In a second direction, the reinforcing part is arranged between two opposite sides of the printing groove; wherein the second direction intersects the first direction.

2. The printing screen according to claim 1, characterized in that The reinforcing part is arranged corresponding to the part of the printing groove along the first direction, so that the printing groove has a first opening section and a second opening section along the first direction, and the reinforcing part is located between the first opening section and the second opening section.

3. The printing screen according to claim 1, characterized in that The reinforcing part comprises at least one of a comb structure, a grid structure, a honeycomb structure, a ring structure or a fold line structure.

4. The printing screen according to claim 1, characterized in that The reinforcing part has a plurality of linear substructures, and the plurality of linear substructures are arranged at intervals to form a hollow area; or the plurality of linear substructures are connected to form a hollow area; the hollow area is communicated with the printing groove.

5. The printing screen according to claim 4, characterized in that When the reinforcing part is the comb structure, the comb structure comprises a plurality of linear substructures; the plurality of linear substructures are arranged at intervals in the first direction, a hollow area is formed between adjacent two linear substructures, and the hollow area is communicated with the printing groove. The area of the cross section of the linear substructure is 16 μm 2 ~ 225 μm 2 The cross section is a plane constituted by the first direction and the thickness direction of the screen body.

6. The printing screen according to claim 4, characterized in that In the second direction, each linear substructure transversely crosses the printing groove, and each linear substructure is arranged between two opposite sides of the printing groove. Wherein, the second direction intersects the first direction. The size of the printing groove in the second direction is width; in the first direction, the part of the printing groove corresponding to the reinforcing part is configured as a width gradient part, and the distance between adjacent two linear substructures becomes larger as the width of the width gradient part becomes narrower.

7. The printing screen according to claim 6, characterized in that The linear diameter of the linear substructure is 6 μm to 15 μm; 8. The printing screen according to claim 6, characterized in that And / or, the distance D1 between adjacent two linear substructures is 0.042 mm to 0.084 mm. When the reinforcing part is the honeycomb structure, in the second direction, the honeycomb structure is arranged between two opposite sides of part of the printing groove; the honeycomb structure comprises a plurality of honeycomb grids, the inner circumferential area of each honeycomb grid is a hollow area, the hollow area is communicated with the printing groove; wherein, the second direction intersects the first direction.

9. The printing screen according to claim 4, characterized in that The screen body comprises a plurality of metal sub-layers, and the plurality of metal sub-layers are sequentially stacked in the thickness direction of the screen body.

10. The printing screen according to any one of claims 1 to 9, characterized in that, The plurality of metal sub-layers comprise a printing shaping layer and a skeleton layer, in the feeding direction of the screen body, the skeleton layer is located in front of the printing shaping layer, and the reinforcing part is arranged on the skeleton layer. In the first direction, the part of the printing groove staggered with the reinforcing part is a first printing part, the size of the first printing part in the second direction is width, and the second direction intersects the first direction.

11. The printing screen according to claim 10, characterized in that ​ The width of the first printing part in the printing shaping layer is W1, and the width of the first printing 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 printing part in the printing shaping layer is 3-15 μm, and the width W2 of the first printing part in the skeleton layer is 100-150 μm.

13. The printing screen according to claim 10, characterized in that The part of the printing groove corresponding to the reinforcing part is configured as a width narrowing part in the skeleton layer, the size of the width narrowing part in the second direction is width, and the width of the width narrowing part narrows along the direction of the pulp feeding 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 sub-layers further comprise a bonding layer, which is connected between 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 material of the printing shaping layer is nickel alloy; And / or, the thickness T1 of the printing shaping layer is 2-20 μm; And / or, the material of the skeleton layer is nickel alloy; And / or, the thickness T2 of the skeleton layer is 2-20 μm; And / or, 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 70-80 nm.

16. The printing screen according to any one of claims 1 to 9, characterized in that In the first direction, the part of the printing groove staggered with the reinforcing part is configured to print a current collecting grid line of a solar cell; The reinforcing part comprises a first reinforcing part configured to print a first connecting structure connected to the current collecting grid line, and the first connecting structure is arranged at the intersection of the current collecting grid line and a bus grid line; And / or, the reinforcing part comprises a second reinforcing part configured to print a second connecting structure connected to the current collecting grid line, and in the first direction, the second connecting structure is staggered with a bus grid line and both ends of the second connecting structure are connected to the same current collecting grid line.

17. The printing screen according to claim 16, characterized in that When the reinforcing part comprises a first reinforcing part, the part of the printing groove corresponding to the first reinforcing part is a second printing part; The length L2 of the second printing part in the first direction is 0.3-2 mm; and / or, the size of the second printing part in the second direction is width; in the first direction, the width of the second printing part narrows from the middle to both ends, the width W4 of the widest part of the second printing part is 10-100 μm, and the width W5 of the narrowest part of the second printing part is 5-60 μm; And / or, when the reinforcing part comprises a second reinforcing part, the part 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 0.1-2 mm, and the width W6 of the third printing part in the second direction is 8-100 μm; Wherein, the first direction intersects the second direction.

18. The printing screen according to any one of claims 1 to 9, characterized in that In the first direction, the part of the printing groove staggered with the reinforcing part is a first printing part, and the opening rate of the first printing part is 80-100%; the opening rate of the reinforcing part is 30-70%.

19. The printing screen according to any one of claims 1 to 9, characterized in that A plurality of the reinforcing portions are arranged corresponding to one of the printing grooves, and the plurality of the reinforcing portions are arranged at intervals in the first direction.

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

21. The printing screen according to claim 20, characterized in that In the first direction, the size of the screen body is D2, the interval between two adjacent reinforcing portions is D3, and D3 / D2=1%~20%. In the first direction, the size of the screen body is D2, the interval between two adjacent reinforcing portions is D3, and D3 / D2=1%~20%.

22. The printing screen according to any one of claims 1 to 9, characterized in that In the first direction, the size of the screen body is D2, the interval between two adjacent reinforcing portions is D3, and D3 / D2=1%~20%. The reinforcing portion is arranged between at least one side or both sides in the thickness direction of the screen body.

23. A printing screen, characterized in that The printing groove is arranged at intervals in a second direction intersecting the first direction. The screen body is provided with a printing groove extending in a first direction, the printing groove penetrating through the thickness direction of the screen body. In the first direction, the printing groove has a first printing portion and a second printing portion connected in sequence, the first printing portion is a high opening with an opening rate of 80%~100%, and the second printing portion is provided with a first reinforcing portion in a hollowed-out manner; in a second direction, the first reinforcing portion is at least partially connected between two opposite sides of the second printing portion. In the first direction, the printing groove has a first printing portion and a third printing portion connected in sequence, the first printing portion is a high opening with an opening rate of 80%~100%, and the third printing portion is provided with a second reinforcing portion in a hollowed-out manner; in a second direction, the second reinforcing portion is at least partially connected between two opposite sides of the third printing portion. The second direction intersects the first direction. The steps include:

24. A method of making a printing screen as claimed in any one of claims 1 to 23, characterized in that Providing a screen semi-finished product with the printing groove; Manufacturing the reinforcing portion on the printing groove. The solar cell pre-product is provided with a current collecting grid line arranged on the surface of the solar cell pre-product and extending in the first direction.

25. A solar cell, characterized by The solar cell further comprises a bus grid line extending in a second direction intersecting the first direction. The connecting structure comprises a first connecting structure arranged at the intersection of the current collecting grid line and the bus grid line. The connecting structure comprises a second connecting structure, in the first direction, the second connecting structure is staggered with the bus grid line and both ends of the second connecting structure are connected to the current collecting grid line. ​ ​ 26. The solar cell of claim 25, wherein, ​ ​ ​ ​ 27. The solar cell of claim 26, wherein, When the connection structure comprises a first connection structure, the maximum height of the first connection structure is H2, and the height of the current collecting grid line is H3; wherein H3 / H2 = 20%~90%.

28. The solar cell of claim 27, wherein, The maximum height H2 of the first connection structure is 3.5 μm~15 μm; and / or, the height H3 of the current collecting grid line is 3 μm~10 μm.

29. The solar cell of claim 26, wherein, When the connection structure comprises a first connection structure, the length L4 of the first connection structure in the first direction is 0.5 mm~2 mm; and / or, in the first direction, the width of the first connection structure narrows from the middle to both ends, the width W7 of the widest part of the first connection structure is 10 μm~100 μm, and the width W8 of the narrowest part of the first connection structure is 5 μm~60 μm.

30. The solar cell of claim 26, wherein, When the connection structure comprises a second connection structure, the length L5 of the second connection structure is 0.1 mm~2 mm; and / or, the width W9 of the second connection structure is 8 μm~100 μm; and / or, the maximum height H4 of the second connection structure is 2 μm~12 μm; and / or, the width W10 of the current collecting grid line is 5 μm~20 μm.

31. The solar cell according to any one of claims 26 to 30, characterized in that, The number of the current collecting grid lines and the number of the bus grid lines are both plural, the plural bus grid lines are arranged at intervals along the first direction, the plural current collecting grid lines are arranged at intervals along the second direction, and each current collecting grid line intersects with the plural bus grid lines; Each current collecting grid line is connected with plural connection structures, the plural connection structures connected with the same current collecting grid line comprise several first connection structures and several second connection structures, each first connection structure is arranged at the intersection of the current collecting grid line and each bus grid line, and in the first direction, each second connection structure is located between two adjacent bus grid lines and both ends of the second connection structure are connected with the current collecting grid line. The first direction is perpendicular to the second direction.

32. The solar cell according to any one of claims 25 to 30, wherein, The grid line smoothness factor of the current collecting grid line is less than the grid line smoothness factor of the connection structure.

33. The solar cell of claim 32, wherein, The grid line smoothness factor of the current collecting grid line is less than 1; and / or, the grid line smoothness factor of the connection structure is 1~8.

34. The solar cell according to any one of claims 25 to 30, wherein, The solar cell pre-product comprises a silicon substrate, a doped layer, and a first functional film, the doped layer and the first functional film are arranged on the surface of the silicon substrate in a direction away from the silicon substrate; The connection structure and the current collecting grid line are both arranged on the first functional film and in ohmic contact with the doped layer through the first functional film.

35. A photovoltaic module, comprising: The solar cell pre-product comprises a silicon substrate, a doped layer, and a first functional film, the doped layer and the first functional film are arranged on the surface of the silicon substrate in a direction away from the silicon substrate; The connection structure and the current collecting grid line are both arranged on the first functional film and in ohmic contact with the doped layer through the first functional film. The solar cell pre-product comprises a silicon substrate, a doped layer, and a first functional film, the doped layer and the first functional film are arranged on the surface of the silicon substrate in a direction away from the silicon substrate; The connection structure and the current collecting grid line are both arranged on the first functional film and in ohmic contact with the doped layer through the first functional film. The solar cell pre-product comprises a silicon substrate, a doped layer, and a first functional film, the doped layer and the first functional film are arranged on the surface of the silicon substrate in a direction away from the silicon substrate; The connection structure and the current collecting grid line are both arranged on the first functional film and in ohmic contact with the doped layer through the first functional film.

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