Screen structure, solar cell, photovoltaic module and method for printing solar cell

Abstract

The invention discloses a screen printing plate structure, a solar cell, a photovoltaic module and a method for printing the solar cell, the screen printing plate structure comprises a first screen printing plate and a second screen printing plate, the first screen printing plate comprises a substrate, the substrate is provided with a plurality of auxiliary grid printing areas, the plurality of auxiliary grid printing areas are arranged at intervals along a first direction, each auxiliary grid printing area comprises a plurality of auxiliary grid printing holes, and the plurality of auxiliary grid printing holes are arranged at intervals in the second direction, and the plurality of auxiliary grid printing holes of each auxiliary grid printing area are configured to form auxiliary grids with fractures on the solar cell semi-finished product. The second screen printing plate is provided with a connection printing area, the connection printing area is configured to enable a connection structure located at the fracture to be formed on the solar cell semi-finished product, and the connection structure is configured to be connected between the auxiliary grids located at the two sides of the fracture in the second direction. According to the screen structure, the solar cell, the photovoltaic module and the method for printing the solar cell, the line width of the auxiliary grid is narrowed, the slurry cost is reduced, and meanwhile the defects of grid breakage, virtual printing and the like of the auxiliary grid can be reduced.

Description

TECHNICAL FIELD

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

[0002] At present, the electrode structure of a solar cell mainly adopts a screen printing process, and a grid line is formed on a solar cell semi-finished product through a preset pattern on a screen.

[0003] In the related art, in order to reduce the loss of paste and the process cost of a solar cell, a method of narrowing the line width of a sub-grid is usually adopted, but narrowing the line width of a sub-grid will cause printing defects such as broken grid and ghost printing. SUMMARY

[0004] Embodiments of the present application disclose a screen structure, a solar cell, a photovoltaic module, and a method for printing a solar cell, which can reduce the line width of a sub-grid, reduce the cost of paste, and reduce the occurrence of defects such as broken grid and ghost printing of a sub-grid.

[0005] To achieve the above object, in a first aspect, embodiments of the present application disclose a screen structure applied to a solar cell, wherein the solar cell comprises a solar cell semi-finished product, and the screen structure comprises:

[0006] a first screen, comprising a substrate, wherein the substrate is provided with a plurality of sub-grid printing areas, the plurality of sub-grid printing areas are arranged at intervals along a first direction, each of the sub-grid printing areas comprises a plurality of sub-grid printing holes, and the plurality of sub-grid printing holes in each of the sub-grid printing areas are arranged at intervals along a second direction, and the plurality of sub-grid printing holes in each of the sub-grid printing areas are configured to form a sub-grid with a fracture on the solar cell semi-finished product;

[0007] a second screen, wherein the second screen is provided with a connecting printing area, and the connecting printing area is configured to form a connecting structure on the solar cell semi-finished product, the connecting structure is configured to connect the sub- grids on both sides of the fracture along the second direction; and

[0008] wherein the first direction and the second direction intersect.

[0009] As an optional implementation, in the embodiments of the first aspect of the present application, the width D1 of the sub-grid printing hole along the first direction is 2 μm to 30 μm.

[0010] As an optional implementation, in the embodiments of the first aspect of the present application, along the second direction, an interval area is formed between two adjacent sub-grid printing holes, the length of the sub-grid printing hole along the second direction is D2, the width of the interval area along the second direction is D3, and D2 / D3 is 35 to 240.

[0011] As an optional implementation, in the embodiment of the first aspect of the present application, the length D2 of the sub-grid printing hole in the second direction is 5mm-30mm, and the width D3 of the interval area in the second direction is 0.05mm-1.5mm.

[0012] As an optional implementation, in the embodiment of the first aspect of the present application, the connection printing area comprises a first connection printing hole, a second connection printing hole and an intermediate connection printing hole, the intermediate connection printing hole is communicated between the first connection printing hole and the second connection printing hole, the first connection printing hole is configured to form a first connection line on the solar cell semi-finished product, and the first connection line is connected to the sub-grid on one side of the fracture in the second direction, the second connection printing hole is configured to form a second connection line on the solar cell semi-finished product, and the second connection line is connected to the sub-grid on the other side of the fracture in the second direction, and the intermediate connection printing hole is configured to form an intermediate connection line on the solar cell semi-finished product, and the intermediate connection line is connected between the first connection line and the second connection line.

[0013] As an optional implementation, in the embodiment of the first aspect of the present application, the width of the sub-grid printing hole in the first direction is D1, and the shortest length of the first connection printing hole and the second connection printing hole in the first direction is D4, D4≥D1.

[0014] As an optional implementation, in the embodiment of the first aspect of the present application, the length D5 of the connection printing area in the second direction is 0.05mm-1.5mm.

[0015] As an optional implementation, in the embodiment of the first aspect of the present application, the shortest length D4 of the first connection printing hole and the second connection printing hole in the first direction is 20μm-200μm, and / or, the width D6 of the first connection printing hole and the second connection printing hole in the second direction is 10μm-200μm, and / or, the width D7 of the intermediate connection printing hole in the first direction is 10μm-200μm.

[0016] As an optional implementation, in the embodiment of the first aspect of the present application, the shape of the connection printing area comprises at least one of H type, N type or inverted 8 type.

[0017] As an optional implementation, in the embodiment of the first aspect of the present application, the second screen is not provided with the main grid printing area, and in the second direction, a spacing area is formed between two adjacent sub-grid printing holes, the length of the sub-grid printing hole in the second direction is D2, the width of the spacing area in the second direction is D3, the number of the spacing areas is M, and the opening rate of the first screen is F, F = D2(M+1) / [D2(M+1)+D3*M], 90%≤F<100%.

[0018] As an optional implementation, in the embodiment of the first aspect of the present application, the second screen is further provided with a main grid printing area, and the main grid printing area is configured to form a main grid on the solar cell semi-finished product.

[0019] The main grid printing area is arranged apart from the connection printing area in the second direction, and / or the connection printing area at least partially communicates with the main grid printing area.

[0020] As an optional implementation, in the embodiment of the first aspect of the present application, the number of the main grid printing areas is N, and in the second direction, a spacing area is formed between two adjacent sub-grid printing holes, and the number M of the spacing areas of each sub-grid printing area is: 1 / 10N≤M≤20N; wherein N is an integer and N≥1, and M is an integer.

[0021] As an optional implementation, in the embodiment of the first aspect of the present application, the main grid printing area includes a plurality of main grid printing areas, and the plurality of main grid printing areas are arranged apart from each other in the second direction. When the main grid printing area is arranged apart from the connection printing area in the second direction, the connection printing area is located between two adjacent main grid printing areas.

[0022] As an optional implementation, in the embodiment of the first aspect of the present application, when the main grid printing area is arranged apart from the connection printing area in the second direction, the second screen is further provided with a main grid overlap printing area, the main grid overlap printing area is at least partially located on the main grid printing area and communicates with the main grid printing area, and the main grid overlap printing area is configured to form a main grid overlap structure at the intersection of the main grid and the sub-grid on the solar cell semi-finished product.

[0023] As an optional implementation, in the embodiment of the first aspect of the present application, the substrate is further provided with a sub-grid overlap printing area, the sub-grid overlap printing area is at least partially located on the sub-grid printing area and communicates with the sub-grid printing hole, the sub-grid overlap printing area is configured to form a sub-grid overlap structure on the solar cell semi-finished product, and the sub-grid overlap structure is arranged to at least partially overlap with the main grid overlap structure.

[0024] As an optional implementation, in the embodiment of the first aspect of the present application, the main grid overlap structure is wrapped in the secondary grid overlap structure; or,

[0025] The secondary grid overlap structure is wrapped in the main grid overlap structure.

[0026] As an optional implementation, in the embodiment of the first aspect of the present application, when the main grid overlap structure is wrapped in the secondary grid overlap structure, the maximum width T1 of the main grid overlap printing area in the first direction is 30 μm-80 μm, the minimum width T2 of the main grid overlap printing area in the first direction is 13 μm-80 μm, the length T3 of the main grid overlap printing area in the second direction is 0.6 mm-1.6 mm, the maximum width T4 of the secondary grid overlap printing area in the first direction is 15 μm-70 μm, the minimum width T5 of the secondary grid overlap printing area in the first direction is 10 μm-70 μm, and the length T6 of the secondary grid overlap printing area in the second direction is 0.5 mm-1.5 mm; or,

[0027] When the secondary grid overlap structure is wrapped in the main grid overlap structure, the maximum width T1 of the main grid overlap printing area in the first direction is 15 μm-70 μm, the minimum width T2 of the main grid overlap printing area in the first direction is 10 μm-70 μm, the length T3 of the main grid overlap printing area in the second direction is 0.5 mm-1.5 mm, the maximum width T4 of the secondary grid overlap printing area in the first direction is 30 μm-80 μm, the minimum width T5 of the secondary grid overlap printing area in the first direction is 13 μm-80 μm, and the length T6 of the secondary grid overlap printing area in the second direction is 0.6 mm-1.6 mm.

[0028] In a second aspect, the present application also discloses a solar cell, comprising:

[0029] A solar cell semi-product;

[0030] An electrode structure, the electrode structure comprising a plurality of secondary grids and a connecting structure, the plurality of secondary grids being arranged at intervals along a first direction, each of the secondary grids comprising a plurality of sub-secondary grids, the plurality of sub-secondary grids being arranged at intervals in a second direction to form a break between two adjacent sub-secondary grids, and the connecting structure being located at the break and connected between the two adjacent sub-secondary grids in the second direction.

[0031] The first direction and the second direction intersect.

[0032] As an optional implementation, in the embodiment of the second aspect of the present application, the width W1 of the secondary grid in the first direction is 4 μm-30 μm.

[0033] As an optional implementation, in the embodiments of the second aspect of the present application, the height H of the cross section of the sub-grid is 1-10 μm, and / or the smoothness factor of the sub-grid in the height direction is less than or equal to 1.

[0034] As an optional implementation, in the embodiments of the second aspect of the present application, the connection structure comprises a first connection line, a second connection line and an intermediate connection line, the first connection line is connected to one of the sub-sub-grids on one side of the fracture in the second direction, the second connection line is connected to the other sub-sub-grid on the other side of the fracture in the second direction, and the intermediate connection line is connected between the first connection line and the second connection line.

[0035] As an optional implementation, in the embodiments of the second aspect of the present application, the width of the sub-grid in the first direction is W1, the shortest length of the first connection line and the second connection line in the first direction is W2, and W2≥W1.

[0036] As an optional implementation, in the embodiments of the second aspect of the present application, the length W3 of the connection structure in the second direction is 0.05-1.6 mm.

[0037] As an optional implementation, in the embodiments of the second aspect of the present application, the shortest length W2 of the first connection line and the second connection line in the first direction is 40-120 μm, and / or the width W4 of the first connection line and the second connection line in the second direction is 2-60 μm, and / or the width W5 of the intermediate connection line in the first direction is 2-60 μm.

[0038] As an optional implementation, in the embodiments of the second aspect of the present application, the shape of the connection structure comprises at least one of H type, N type or inverted 8 type.

[0039] As an optional implementation, in the embodiments of the second aspect of the present application, the electrode structure further comprises a main grid, the main grid is arranged apart from the fracture in the second direction, and / or the fracture is located on the main grid.

[0040] As an optional implementation, in the embodiments of the second aspect of the present application, the main grid comprises a plurality of main grids, the plurality of main grids are arranged apart in the second direction, and when the main grid is arranged apart from the fracture in the second direction, the fracture is located between two adjacent main grids.

[0041] As an optional implementation, in the embodiments of the second aspect of the present application, when the main grid is arranged to be spaced apart from the fracture in the second direction, the electrode structure further comprises a main grid overlap structure, the main grid overlap structure is connected to the main grid, and the main grid overlap structure is located at the intersection of the main grid and the sub-sub grid.

[0042] As an optional implementation, in the embodiments of the second aspect of the present application, the electrode structure further comprises a sub-grid overlap structure, the sub-grid overlap structure is connected to the sub-sub grid, and the sub-grid overlap structure is arranged to overlap at least part of the main grid overlap structure.

[0043] As an optional implementation, in the embodiments of the second aspect of the present application, the main grid overlap structure is wrapped in the sub-grid overlap structure; or,

[0044] The sub-grid overlap structure is wrapped in the main grid overlap structure.

[0045] As an optional implementation, in the embodiments of the second aspect of the present application, when the main grid overlap structure is wrapped in the sub-grid overlap structure, the maximum width L1 of the main grid overlap structure in the first direction is 35 μm to 90 μm, the minimum width L2 of the main grid overlap structure in the first direction is 20 μm to 90 μm, the length L3 of the main grid overlap structure in the second direction is 0.65 mm to 1.7 mm, the maximum width L4 of the sub-grid overlap structure in the first direction is 20 μm to 75 μm, the minimum width L5 of the sub-grid overlap structure in the first direction is 15 μm to 75 μm, and the length L6 of the sub-grid overlap structure in the second direction is 0.55 mm to 1.6 mm; or,

[0046] When the sub-grid overlap structure is wrapped in the main grid overlap structure, the maximum width L1 of the main grid overlap structure in the first direction is 20 μm to 75 μm, the minimum width L2 of the main grid overlap structure in the first direction is 15 μm to 75 μm, the length L3 of the main grid overlap structure in the second direction is 0.55 mm to 1.6 mm, the maximum width L4 of the sub-grid overlap structure in the first direction is 35 μm to 90 μm, the minimum width L5 of the sub-grid overlap structure in the first direction is 20 μm to 90 μm, and the length L6 of the sub-grid overlap structure in the second direction is 0.65 mm to 1.7 mm.

[0047] As an optional implementation, in the embodiment of the second aspect of the application, the electrode structure further comprises a pad and a fishhook, the pad comprises a first pad and a second pad, the first pad is arranged at both ends of the main grid, and the second pad is arranged on the main grid between the two first pads, and the fishhook is arranged at both ends of the main grid and connected to the first pad;

[0048] The area of the first pad is greater than the area of the second pad.

[0049] In a third aspect, the application further discloses a photovoltaic module comprising the solar cell according to the second aspect.

[0050] In a fourth aspect, the application further discloses a method for printing a solar cell by using the screen structure according to the first aspect, the method comprising:

[0051] printing a sub-grid with a fracture on the solar cell semi-finished product by using the first screen;

[0052] printing a plurality of connection structures on the solar cell semi-finished product by using the second screen, so that the connection structures are connected between the sub-grids on both sides of the fracture.

[0053] Compared with the prior art, the application has the following beneficial effects:

[0054] The application discloses a screen structure, which comprises a first screen and a second screen. The sub-grid printing area is directly arranged on the substrate of the first screen, so that the sub-grid printing area can directly infiltrate the paste during printing, the process of paste infiltration is more smooth and uniform, and thus the printing defects such as sub-grid fracture and weak printing can be prevented. Moreover, the direct hole opening mode on the steel plate can also make the width of the sub-grid printing area smaller according to the needs, and thus the sub-grid with a narrower line width can be printed, and the wet weight is reduced.

[0055] On this basis, the sub-grid printing area is divided into spaced sub-grid printing holes. In the case that the number of sub-grid printing areas is large, the structural strength of the first screen is increased, and the mechanical structural stability of the first screen is improved, so that the risk of screen burst of the first screen during printing is reduced, and the service life of the first screen is improved.

[0056] Meanwhile, the connection printing area is arranged on the second screen, so that the paste forms the connection structure on the substrate through the connection printing area and is connected between the sub-grids on both sides of the fracture, and the sub-grid with the fracture forms a complete grid line. In this way, the current can be collected through the sub-grid, and during laser-induced sintering and IV / EL testing, the solar cell can be powered on as a whole and tested without modifying the equipment, which is beneficial to improving the universality of the measuring equipment. BRIEF DESCRIPTION OF DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without any creative effort.

[0058] Figure 1 Structure schematic diagram of the first screen disclosed by the first aspect of the present application;

[0059] Figure 2 Structure schematic diagram of the second screen disclosed by the first aspect of the present application;

[0060] Figure 3 Structure schematic diagram of the first screen disclosed by the first aspect of the present application; Figure 1

[0061] Figure 4 Structure schematic diagram of the connection printing area disclosed by the first aspect of the present application;

[0062] Figure 5 Structure schematic diagram of the connection printing area disclosed by the first aspect of the present application;

[0063] Figure 6 Structure schematic diagram of the connection printing area disclosed by the first aspect of the present application; Figure 2

[0064] Figure 7 Structure schematic diagram of the main grid lap printing area disclosed by the first aspect of the present application;

[0065] Figure 8 Structure schematic diagram of the auxiliary grid lap printing area disclosed by the first aspect of the present application;

[0066] Figure 9 Structure schematic diagram of the first screen disclosed by the second aspect of the present application;

[0067] Figure 10 Structure schematic diagram of the second screen disclosed by the second aspect of the present application;

[0068] Figure 11 Structure schematic diagram of the connection of the main grid and the auxiliary grid disclosed by the second aspect of the present application;

[0069] Figure 12 Structure schematic diagram of the electrode disclosed by the third aspect of the present application;

[0070] Figure 13 Structure schematic diagram of the electrode disclosed by the third aspect of the present application; Figure 12

[0071] Figure 14 ​​​A cross-sectional structure of the vice grid according to the third aspect of the present application;

[0072] Figure 15 A structure diagram of the connecting structure according to the third aspect of the present application;

[0073] Figure 16 A structure diagram of the main grid according to the third aspect of the present application;

[0074] Figure 17 A structure diagram of the main grid according to the third aspect of the present application;

[0075] Figure 18 A structure diagram of the main grid according to the third aspect of the present application;

[0076] Figure 19 A topography diagram of the vice grid formed by the steel screen printing;

[0077] Figure 20 A topography diagram of the vice grid formed by the steel screen printing;

[0078] Figure 21 A topography diagram of the vice grid formed by the first screen printing of the present application;

[0079] Figure 22 A topography diagram of the vice grid formed by the first screen printing of the present application;

[0080] Figure 23 A cross-sectional profile diagram of the vice grid formed by the steel screen printing;

[0081] Figure 24 A cross-sectional profile diagram of the vice grid formed by the first screen printing of the present application.

[0082] Explanation of reference signs:

[0083] 10, screen structure; 11, first screen; 110, substrate; 111, vice grid printing area; 111a, vice grid printing hole; 111b, interval area; 112, vice grid overlap printing area; 12, second screen; 121, connecting printing area; 1211, first connecting printing hole; 1212, second connecting printing hole; 1213, intermediate connecting printing hole; 122, main grid printing area; 123, main grid overlap printing area;

[0084] 20, solar cell; 21, solar cell semi-product; 22, electrode structure; 221, sub-grid; 221a, break; 221b, sub-sub-grid; 222, connection structure; 2221, first connection line; 2222, second connection line; 2223, intermediate connection line; 223, main-grid; 224, main-grid overlap structure; 225, sub-grid overlap structure; 226, pad; 226a, first pad; 226b, second pad; 227, fish-tail;

[0085] X, first direction; Y, second direction;

[0086] D1, width of sub-grid printing hole in first direction; D2, length of sub-grid printing hole in second direction; D3, width of interval area in second direction; D4, shortest length of first and second connection printing hole in first direction; D5, length of connection printing area in second direction; D6, width of first and second connection printing hole in second direction; D7, width of intermediate connection printing hole in first direction;

[0087] T1, maximum width of main-grid overlap printing area in first direction; T2, minimum width of main-grid overlap printing area in first direction; T3, length of main-grid overlap printing area in second direction; T4, maximum width of sub-grid overlap printing area in first direction; T5, minimum width of sub-grid overlap printing area in first direction; T6, length of sub-grid overlap printing area in second direction;

[0088] W1, width of sub-grid in first direction; H, height of cross section of sub-grid; W2, shortest length of first and second connection line in first direction; W3, length of connection structure in second direction; W4, width of first and second connection line in second direction; W5, width of intermediate connection line in first direction;

[0089] L1, maximum width of main-grid overlap structure in first direction; L2, minimum width of main-grid overlap structure in first direction; L3, length of main-grid overlap structure in second direction; L4, maximum width of sub-grid overlap structure in first direction; L5, minimum width of sub-grid overlap structure in first direction; L6, length of sub-grid overlap structure in second direction. DETAILED DESCRIPTION

[0090] The technical solutions in the embodiments of the present application will be described clearly and completely 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 the other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0091] In the present application, the terms "upper", "lower", "left", "right" and the like indicate the orientation or positional relationship based on 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.

[0092] In addition, in addition to being used to indicate the orientation or positional relationship, the above-mentioned partial 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 circumstances.

[0093] In addition, the terms "provided with", "provided with", "connected" should be broadly understood. For example, it can be fixedly connected, detachably connected, or integrally constructed; it can be mechanically connected or electrically connected; 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-mentioned terms in the present application can be understood according to the specific circumstances.

[0094] In addition, the terms "first", "second" and the like are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used 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.

[0095] Solar cells, due to their clean, safe, convenient and efficient characteristics, have become the focus of attention and development of the industry all over the world. With the continuous innovation of technology, the conversion efficiency of solar cells is also increasing, and high efficiency and low cost have gradually become the trend of the development of solar cell technology. For example, the tunnel oxide passivation contact solar cell solves the problem of carrier selection passivation contact of the cell and improves the conversion efficiency of the solar cell, and its conversion efficiency can reach 28.7%.

[0096] In the related art, the technology of narrowing the line width of the grid lines is usually adopted to obtain a low-wet-weight battery piece under the premise of maintaining or reducing the conduction resistance, reduce the surface shading and conductive paste consumption, and reduce the cost of the solar cell, which is of great significance to the cost reduction and efficiency improvement of the overall solar cell process. In the related art, in order to narrow the line width of the grid lines, the line width of the steel screen is shrunk to print the grid lines by optimizing the screen. Although this method can effectively reduce the production cost of the battery piece, with the pressure of cost reduction and efficiency improvement of the photovoltaic market, the technology of simply optimizing the screen to adapt to a narrower line width will be limited to a certain extent. Specifically, after the steel screen is used to shrink the line width to a certain extent, a large number of printing defects will occur.

[0097] The inventor has found that, due to the fact that the steel screen is formed in a woven manner, the steel wires are connected in a staggered manner, the steel wires are not in the same plane, and the staggered steel wires will block the printing hole, which will cause the paste to be difficult to infiltrate during printing, resulting in a low transfer rate, and thus the paste printing is uneven, and problems such as broken grid, ghosting, poor flatness, etc. Therefore, if the line width of the steel screen is simply narrowed to a certain limit, it cannot be further narrowed, otherwise it will cause serious printing defects, which makes the steel screen narrowing method an obstacle to reducing the cost and improving the efficiency of the solar cell.

[0098] Therefore, the inventor tries to introduce a new process screen, which includes a substrate, and a printing hole is formed on the substrate, so that there is no blockage at the printing hole, achieving 100% opening rate at the printing hole, so that the paste can pass through the screen printing hole without blockage during printing, so that the paste infiltrates more smoothly and uniformly, thereby achieving ultra-fine line printing, which can narrow the line width of the grid lines and obtain a low-wet-weight battery piece, while reducing the consumption of conductive paste, reducing grid line breakage, ghosting, poor flatness and other defects. However, the inventor has found that the screen with unblocked printing holes has a short service life. Specifically, the current screen is mainly used for printing the sub-grid, and when used as a screen for printing the sub-grid, a horizontal opening is usually formed on the surface of the screen to allow the paste to flow smoothly and unobstructed through the screen at the place where it needs to be printed. However, in order to improve the printing efficiency, multiple sub-grids are often formed during printing, which will greatly damage the mechanical structure stability of the screen, and the screen will easily explode during printing.

[0099] In order to solve the problem of low screen life, the inventors change the originally straight auxiliary grid printing hole to a segmented auxiliary grid printing hole to enhance the mechanical properties of the screen. Since the auxiliary grid usually uses a burn-through type silver paste to corrode the passivation layer and contact the silicon substrate, the current is collected and converged on the main grid through the solder ribbon or directly through the solder ribbon. However, the segmented auxiliary grid printing hole on the screen forms an auxiliary grid with a fracture, which affects the transmission of current and causes the battery surface to be unable to be electrically injected.

[0100] Based on this, the present application provides a screen structure, which can include a first screen and a second screen. By directly setting auxiliary grid printing holes on the substrate of the first screen, the auxiliary grid printing holes can directly infiltrate the paste during printing, and the process of paste infiltration is more smooth and uniform, thereby preventing printing defects such as auxiliary grid fracture and ghosting. In addition, the direct hole opening method can also make the width of the auxiliary grid printing hole smaller according to the needs, and further can print narrower auxiliary grid lines. On this basis, the auxiliary grid printing area is divided into spaced auxiliary grid printing holes. In the case of a large number of auxiliary grid printing areas, the structural strength of the first screen is increased, and the mechanical structural stability of the first screen is improved, thereby reducing the risk of screen explosion during printing, and further improving the service life of the first screen. Thus, while being able to form narrower auxiliary grid lines, reducing the wet weight, and improving the defects such as auxiliary grid fracture and ghosting after printing, the structural strength of the screen can be increased, thereby reducing the risk of screen explosion during printing and improving the service life of the screen.

[0101] On this basis, the present application further sets a connecting printing area on the second screen, so that the paste forms a connecting structure on the substrate through the connecting printing area and is connected between the auxiliary grids on both sides of the fracture. The auxiliary grid with a fracture forms a complete grid line. Such a setting allows the current to be collected through the auxiliary grid, and without modifying the equipment, the solar cell can be powered as a whole and tested during laser-induced sintering and IV (I-V curve test, photoelectric performance test) / EL (Electroluminescent, electroluminescent test) testing, which is beneficial to improve the versatility of the measurement equipment.

[0102] The technical solutions of the present application will be further described below in conjunction with the embodiments and the drawings.

[0103] In a first aspect, the present application provides a screen structure 10 which can be applied to a solar cell 20 including a solar cell semi-finished product 21 and an electrode structure 22. The screen structure 10 can be used to print paste on the surface of the solar cell semi-finished product 21 according to a certain printing pattern through a printing process, and then sintered to form the electrode structure 22.

[0104] It should be noted that the solar cell semi-finished product 21 can refer to a semi-finished structure of the solar cell 20 before the electrode structure 22 is printed, or can refer to a semi-finished structure of the solar cell 20 after the back electrode structure 22 is printed but before the front electrode structure 22 is printed. For example, the solar cell 20 can include a silicon material, and a medium layer, a front passivation layer and a front anti-reflection layer formed in sequence on the front surface of the silicon material, and a medium layer, a back passivation layer and a back anti-reflection layer formed in sequence on the back surface of the silicon material.

[0105] In the related art, steel wire screen printing is formed by crossing and weaving steel wires of a certain mesh and diameter, and then a screen is made according to the selective ink penetration principle of the formed printing holes, and a fixed pattern of grid lines is formed on the solar cell semi-finished product 21 by printing. Since the steel wires are connected in a staggered manner, the steel wires are not in the same plane, and the staggered connection of the steel wires will cause shielding at the printing holes, which will cause the slurry to be difficult to penetrate during printing, resulting in low transfer rate and uneven printing of the slurry. There are problems such as broken grid, ghosting, poor flatness, etc. In addition, the larger the opening rate of the screen cloth, the better the printability, and correspondingly the higher the degree of thinning. However, the presence of knots in the steel wire screen also limits the flatness of the grid lines. In addition, even if the current printing screen without knots can set the pattern opening between two parallel warp lines or weft lines, the ink penetration performance is improved, but since there are still a large number of warp lines or weft lines arranged in the wide direction at the pattern opening, these screen lines perpendicular to the opening pattern will still block the printing of the silver paste, and the printed grid lines will still form high and low undulations, which will increase the resistivity of the printed electrode pattern, reduce the effective utilization rate of the silver paste, and adversely affect the power generation efficiency of the solar cell.

[0106] Therefore, in order to solve the above problems, in some embodiments, referring to Figure 1 The screen structure 10 can include a first screen 11, and the first screen 11 can include a substrate 110 provided with a plurality of sub-grid printing areas 111, the plurality of sub-grid printing areas 111 being arranged at intervals along a first direction X, and each sub-grid printing area 111 extending along a second direction Y. The first direction X intersects the second direction Y.

[0107] It should be noted that the sub-grid printing area 111 opened on the substrate 110 is not blocked. Compared with the steel wire screen printing plate in the related art, the steel wire or the mesh knot exists in the printing hole, and when printing, the sub-grid printing area 111 opened on the substrate 110 can directly infiltrate the paste, so that the process of infiltrating the paste is more smooth and uniform, thereby preventing the occurrence of sub-grid 221 grid breakage, ghosting and other printing defects, and avoiding the uneven printing of the paste due to the blockage. In addition, the direct opening method can also make the width of the sub-grid printing area 111 smaller according to the need, and then the sub-grid 221 with a narrower line width can be printed.

[0108] It can be understood that the substrate 110 of the first screen plate 11 can be a sheet, and the sub-grid printing area 111 can be a printing channel opened on the substrate 110 and penetrating through the thickness direction of the substrate 110, so that the paste can infiltrate through the sub-grid printing area 111 to the solar cell semi-finished product 21. Specifically, when printing, the first screen plate 11 is arranged corresponding to the solar cell semi-finished product 21, the paste is poured on one side of the substrate 110, and a certain pressure is applied to the part of the substrate 110 with the paste by the squeegee, while the squeegee moves towards the other side of the substrate 110, so that the paste can be squeezed from the sub-grid printing hole 111a by the squeegee to the solar cell semi-finished product 21 during the movement, and the sub-grid 221 printing is realized.

[0109] In the embodiment of the present application, the first direction X can be the longitudinal direction, the second direction Y can be the transverse direction, and the plurality of sub-grid printing areas 111 can be arranged in parallel along the longitudinal direction, or substantially parallel, each sub-grid printing area 111 is in the form of a long strip, and each sub-grid printing area 111 extends along the transverse direction.

[0110] Optionally, the substrate 110 can be a metal, alloy or high polymer material substrate 110 or substrate, when the substrate 110 is a metal substrate 110, it can be, for example, a steel sheet. When the substrate 110 is an alloy substrate 110, it can be, for example, a stainless steel sheet, a nickel-cobalt-iron alloy sheet, etc.; when the substrate 110 is a high polymer material substrate 110, it can be, for example, a polyimide (PI) sheet, a nylon substrate, etc.

[0111] Optionally, the first screen plate 11 can further include a frame, which can be connected to the outer periphery of the substrate 110, for fixing the substrate 110.

[0112] Since the sub-grid printing area 111 is formed by opening a transverse and long straight opening on the substrate 110, when the number of sub-grid printing areas 111 opened on the substrate 110 to meet the number requirement of the sub-grids 221 is large, the structural strength of the first screen plate 11 will be greatly damaged, which may cause the screen plate to burst during printing. In order to improve the structural stability of the first screen plate 11, in some embodiments, each sub-grid printing area 111 can include a plurality of sub-grid printing holes 111a, and the plurality of sub-grid printing holes 111a are arranged at intervals in the second direction Y. The plurality of sub-grid printing holes 111a of each sub-grid printing area 111 are configured to form the sub-grids 221 with the broken part 221a on the solar cell semi-finished product 21. By dividing the sub-grid printing area 111 into the interval sub-grid printing holes 111a, the structural strength of the first screen plate 11 is increased, and the mechanical structural stability of the first screen plate 11 is improved, thereby reducing the risk of the first screen plate 11 bursting during printing, and further improving the service life of the first screen plate 11.

[0113] It can be seen that, by opening a plurality of sub-grid printing areas 111 on the substrate 110 of the first screen plate 11, and dividing each sub-grid printing area 111 into interval sub-grid printing holes 111a, the sub-grids 221 with narrower line width can be printed, the solar cell 20 with low wet weight is obtained, and the printing defects such as broken grid, ghosting and poor flatness of the sub-grids 221 are reduced. At the same time, the structural stability of the first screen plate 11 is improved, thereby facilitating the improvement of the service life of the first screen plate 11.

[0114] Since the sub-grids 221 adopt the burn-through type silver paste to contact the passivation layer and the silicon material, and collect the current to converge on the main grid 223 through the solder strip or directly through the solder strip. The sub-grids 221 with the broken part 221a formed on the solar cell semi-finished product 21 through the interval sub-grid printing holes 111a on the first screen plate 11 are connected between the sub-grids 221 on both sides of the broken part 221a in the second direction Y. Figure 2 In some embodiments, the screen plate structure 10 can further include a second screen plate 12, and the second screen plate 12 is provided with a connection printing area 121 configured to form a connection structure 222 on the solar cell semi-finished product 21 located at the broken part 221a. The connection structure 222 is configured to connect between the sub-grids 221 on both sides of the broken part 221a in the second direction Y.

[0115] It can be understood that, since the connection printing area 121 for forming the connection structure 222 on the solar cell semi-finished product 21 is arranged on another screen plate, the sub-grids 221 with the broken part 221a can be connected while the structural strength of the first screen plate 11 is not affected.

[0116] By setting the connecting printing area 121 on the second screen 12, the connecting structure 222 formed by the connecting printing area 121 is connected between the bus bars 221 on both sides of the break 221a, so that the bus bars 221 with the break 221a on the surface of the solar cell semi-finished product 21 form continuous bus lines. In this way, the current collected by the bus bars 221 can be transmitted, and the solar cell 20 can be powered as a whole and tested without modifying the equipment during laser-induced sintering, IV (I-V curve test, photoelectric performance test) and EL (Electroluminescent, electroluminescent test) tests, which is conducive to improving the versatility of the measuring equipment.

[0117] In the above embodiment, the silver paste used for printing the bus bars 221 is usually a conductive paste with high corrosion strength (such as silver paste), which can burn through the silicon nitride on the surface of the solar cell semi-finished product 21 to make the conductive metal powder contact the silicon material and form a conductive metal-silicon alloy to collect the current inside the solar cell 20. The paste used for printing the connecting structure 222 can be a non-burn-through silver paste or a burn-through silver paste. The non-burn-through silver paste has a lower corrosion degree and does not damage the surface film of the solar cell 20, thereby reducing the damage to the PN junction of the solar cell 20.

[0118] In some embodiments, the bus bar printing hole 111a can be formed by using processes such as laser etching, electroplating, etc. on the first screen 11, so that the printing hole without shielding is formed on the first screen 11. Correspondingly, the connecting printing area 121 provided on the second screen 12 can also be formed by using processes such as laser etching, electroplating, etc.

[0119] In some possible implementations, refer to Figure 3The width D1 of the auxiliary grid printing hole 111a in the first direction X is 2-30 μm. Optionally, D1 can be 4-20 μm, for example, 8 μm, 10 μm or 18 μm, etc.; or D1 can be 4-15 μm, for example, 7 μm, 12 μm or 16 μm, etc.; or D1 can be 4-11 μm, for example, 6.5 μm, 9 μm or 10 μm, etc.; or D1 can be 4-8 μm, for example, 3 μm, 5 μm or 7 μm, etc.; or D1 can be 4-6 μm, for example, 2.5 μm, 4 μm or 6 μm, etc. By limiting the width of the auxiliary grid printing hole 111a in the first direction X within a reasonable range, on the basis of ensuring the processing and forming of the first screen 11, the line width of the auxiliary grid 221 formed can be further narrowed, which is conducive to reducing the printing wet weight of the conductive paste, reducing the optical loss caused by the line width shielding, and effectively reducing the consumption of the paste, and increasing the light receiving area of the battery, improving the short-circuit current and open voltage. If D1 is less than 4 μm, the width of the auxiliary grid printing hole 111a is too small, which not only requires high precision of the forming process of the first screen 11, but also affects the printing difficulty, and leads to the line width of the auxiliary grid 221 being too small, the cross-sectional area of the auxiliary grid 221 being reduced, the contact resistance and line resistance being increased, and finally affecting the current transmission capacity of the solar cell 20. If D1 is greater than 30 μm, the line width of the auxiliary grid 221 formed is increased, which leads to an increase in the consumption of the paste, and affects the light receiving area of the solar cell 20.

[0120] It can be seen that the screen structure 10 of the present application can not only be applied to the printing of the auxiliary grid 221 with a larger width (for example, a line width of 11 μm, 13 μm or 15 μm, etc.), but also can be applied to the printing of the auxiliary grid 221 with a smaller width (for example, a line width of 7 μm or less, such as 3 μm, 4 μm, 5 μm or 6 μm, etc.), so that the application range of the screen structure 10 is wider.

[0121] In some possible embodiments, in the second direction Y, a spacing region 111b is formed between adjacent two auxiliary grid printing holes 111a. The spacing region 111b refers to the substrate 110 entity between the adjacent two auxiliary grid printing holes 111a, and the paste does not infiltrate through the spacing region 111b. It can be seen that the spacing region 111b is provided to disconnect the adjacent two auxiliary grid printing holes 111a, that is, the auxiliary grid printing region 111 is discontinuous, so that the influence on the structural strength of the substrate 110 caused by the continuous auxiliary grid printing region 111 can be avoided.

[0122] Optionally, the length of the auxiliary grid printing hole 111a in the second direction Y is D2, the width of the interval area 111b in the second direction Y is D3, and D2 / D3 is 25-240. For example, it can be 60, 80, 100, etc. By limiting the ratio of the length of the auxiliary grid printing hole 111a in the second direction Y and the width of the interval area 111b in the second direction Y within a reasonable range, the first screen plate 11 has reasonable structural strength while meeting the specification requirements of the formed auxiliary grid 221, thereby greatly guaranteeing the service life of the first screen plate 11.

[0123] In some embodiments, the length D2 of the auxiliary grid printing hole 111a in the second direction Y is 5-30 mm. Optionally, D2 can be 5-20 mm, for example, 8 mm, 10 mm, or 18 mm, etc.; or D2 can be 5-15 mm, for example, 11 mm, 12 mm, or 13 mm, etc.; or D2 can be 5-10 mm, for example, 6 mm, 7 mm, or 9 mm, etc.

[0124] In some embodiments, the width D3 of the interval area 111b in the second direction Y is 0.05-1.5 mm, optionally, D3 can be 0.05-1.2 mm, for example, it can be 0.2 mm, 0.7 mm, or 1 mm, etc.; or D3 can be 0.05-1.0 mm, for example, it can be 0.3 mm, 0.6 mm, or 0.8 mm, etc.; or D3 can be 0.05-0.6 mm, for example, it can be 0.1 mm, 0.4 mm, or 0.5 mm, etc.

[0125] By limiting the size of the auxiliary grid printing hole 111a and the interval area 111b in the second direction Y, the opening rate of the substrate 110 of the first screen plate 11 is large while meeting the structural stability of the first screen plate 11, effectively guaranteeing the transmission of the paste, making the printed grid line effect better, thereby making the first screen plate 11 have the dual advantages of structural stability and paste transmission.

[0126] In some embodiments, the connection printing area 121 can be a rectangular printing hole, which can be configured to form a rectangular connection structure 222 on the solar cell semi-finished product 21, the rectangular connection structure 222 being connected between the auxiliary grids 221 on both sides of the fracture 221a, so that each auxiliary grid 221 is formed as an uninterrupted grid line in the second direction Y.

[0127] Of course, in other embodiments, the connection printing area 121 can also be, for example, a circular printing hole, a circular-like printing hole, or other polygonal holes (such as triangular, pentagonal, or hexagonal, etc.).

[0128] In addition, in some embodiments, referring to Figure 4The connection printing area 121 can include a first connection printing hole 1211, a second connection printing hole 1212, and an intermediate connection printing hole, which is communicated between the first connection printing hole 1211 and the second connection printing hole 1212, the first connection printing hole 1211 is configured to form a first connection line 2221 on the solar cell semi-finished product 21, and the first connection line 2221 is connected to the auxiliary grid 221 on one side of the break 221a in the second direction Y, the second connection printing hole 1212 is configured to form a second connection line 2222 on the solar cell semi-finished product 21, and the second connection line 2222 is connected to the auxiliary grid 221 on the other side of the break 221a in the second direction Y, and the intermediate connection printing hole is configured to form an intermediate connection line 2223 on the solar cell semi-finished product 21, and the intermediate connection line 2223 is connected between the first connection line 2221 and the second connection line 2222.

[0129] Compared with the relatively regular rectangular shape of the connection printing area 121, in this way, the first connection line 2221 formed by the first connection printing area 121 is connected to the auxiliary grid 221 on one side of the break 221a, the second connection line 2222 formed by the second connection printing area 121 is connected to the auxiliary grid 221 on the other side of the break 221a, and the intermediate connection line 2223 formed by the intermediate connection printing area 121 is connected between the first connection line 2221 and the second connection line 2222, so that the auxiliary grid 221 with the break 221a can form a continuous auxiliary grid 221, thereby reducing the amount of paste used, reducing the wet weight of the printed paste, and reducing the manufacturing cost of the solar cell 20 while achieving the current transmission function.

[0130] It should be noted that the first connection printing hole 1211, the second connection printing hole 1212, and the intermediate connection printing hole 1213 are mutually communicated to form the connection printing area 121, and the first connection printing hole 1211 and the second connection printing hole 1212 can extend along the first direction X. Among them, the shapes of the first connection printing hole 1211, the second connection printing hole 1212, and the intermediate connection printing hole 1213 can be different, the width of the intermediate connection printing hole 1213 in the first direction X can be smaller than the width of the first connection printing hole 1211 and the second connection printing hole 1212 in the first direction X, or the width of the intermediate connection printing hole 1213 in the first direction X is gradually changed from the first connection printing hole 1211 to the second connection printing hole 1212, so that the connection printing hole is a non-rectangular, non-trapezoidal, or other shape with a larger opening area, thereby avoiding forming a connection structure 222 on the solar cell semi-finished product 21 that consumes too much paste.

[0131] In some possible implementation manners, in order to improve the fault tolerance of the connection of the sub-grid 221 located on both sides of the fracture 221a, that is, to facilitate the connection of the sub-grid 221 on both sides of the fracture 221a and the connection structure 222, the width of the sub-grid printing hole 111a in the first direction X is D1, and the shortest length of the first connection printing hole 1211 and the second connection printing hole 1212 in the first direction X is D4, and D4≥D1. By limiting the length of the first connection printing hole 1211 and the second connection printing hole 1212 in the first direction X to be greater than the width of the sub-grid printing hole 111a in the first direction X, that is, a sufficient connection area can be provided for stable connection with the sub-grid 221 during printing, and the connection offset of the first connection line 2221 and the second connection line 2222 can be controlled during the formation of the connection structure 222, and the product defect caused by the offset is improved.

[0132] It should be noted that the shortest length of the first connection printing hole 1211 and the second connection printing hole 1212 in the first direction X is D4, which means that the length of the first connection printing hole 1211 and the second connection printing hole 1212 in the first direction X can be equal, or the length of the first connection printing hole 1211 in the first direction X is greater than the length of the second connection printing hole 1212 in the first direction X, or the length of the first connection printing hole 1211 in the first direction X is less than the length of the second connection printing hole 1212 in the first direction X.

[0133] In some possible implementation manners, the length D5 of the connection printing area 121 in the second direction Y is 0.05 mm to 1.5 mm. Alternatively, D5 can be 0.1 mm to 1.2 mm, 0.1 mm to 1.0 mm, or 0.1 mm to 0.8 mm, for example, 0.5 mm, 1.0 mm, or 1.2 mm, and the like. Since the connection structure 222 formed by the connection printing area 121 needs to be located at the fracture 221a, so as to be connected between the grid lines located on both sides of the fracture 221a, therefore, by limiting the length of the connection printing area 121 as a whole to be compatible with the width of the interval area 111b in the second direction Y, the connection structure 222 can have an offset reservation in the second direction Y, which reduces the printing difficulty, thereby reducing the printing defect of the disconnected grid caused by the offset.

[0134] In some embodiments, the shortest length D4 of the first connection printing hole 1211 and the second connection printing hole 1212 in the first direction X is 20 μm to 200 μm. Alternatively, D4 can be 20 μm to 180 μm, 20 μm to 150 μm, or 20 μm to 80 μm, for example, 50 μm, 80 μm, or 100 μm, and the like. By limiting the range of D4, a certain offset amount is reserved when the connection line is printed, which can reduce the printing difficulty.

[0135] In some embodiments, the first connection printing hole 1211 and the second connection printing hole 1212 have a width D6 in the second direction Y of 10 μm to 200 μm. Alternatively, D6 can be 10 μm to 150 μm, 10 μm to 100 μm, or 10 μm to 60 μm, etc., for example, can be 40 μm, 80 μm, or 120 μm, etc. By limiting the range of D6, the amount of paste used is reduced on the basis of being able to connect the connection structure 222 to the auxiliary grid 221.

[0136] In some embodiments, the intermediate connection printing hole 1213 has a width D7 in the first direction X of 10 μm to 200 μm. Alternatively, D7 can be 10 μm to 150 μm, 10 μm to 100 μm, or 10 μm to 60 μm, etc., for example, can be 40 μm, 80 μm, or 120 μm, etc. By limiting the range of D7, the amount of paste used is reduced, the wet weight is reduced, and the light shielding area is reduced while ensuring that the intermediate line formed is effectively connected between the first connection line 2221 and the second connection line 2222.

[0137] It can be seen that by limiting the ranges of D4, D6, and D7, a certain amount of offset can be reserved, a sufficiently large connection area can be provided to stably connect with the auxiliary grid 221, and the use of too much paste due to the first connection printing hole 1211 and the second connection printing hole 1212 being too large can be avoided, and the material cost can be reduced.

[0138] In some possible embodiments, referring to Figure 5 The shape of the connection printing area 121 includes at least one of an H type, an N type, or an inverted 8 type. It can be understood that the second screen 12 can have a plurality of connection printing areas 121, and the plurality of connection printing areas 121 can be the same shape or different shapes. By using the connection printing area 121 having these shapes, the loss of paste can be reduced while ensuring effective connection between the connection structure 222 and the auxiliary grid 221 located on both sides of the break 221a.

[0139] In an example, the width of the intermediate connection printing hole 1213 in the first direction X can be smaller than the shortest length of the first connection printing hole 1211 and the second connection printing hole 1212 in the first direction X, so that the shape of the intermediate connection printing hole 1213 is rectangular, and the first connection printing hole 1211 and the second connection printing hole 1212 can have the same shape and size, both rectangular, so that the overall shape of the connection printing area 121 is H-shaped. In this way, on the one hand, the symmetrical and regular shape can facilitate the processing of the second screen 12; on the other hand, when the first connection line 2221 and the second connection line 2222 formed on the solar cell semi-finished product 21 are connected with the auxiliary grid 221, even if there is an offset error, the connection of the auxiliary grid 221 with the connection line can be guaranteed, so that the connection structure 222 can be effectively connected between the auxiliary grids 221 located on both sides of the fracture 221a, and the loss of paste can be reduced, which is conducive to reducing the cost.

[0140] In another example, the width of the intermediate connection printing hole 1213 in the first direction X can be smaller than the shortest length of the first connection printing hole 1211 and the second connection printing hole 1212 in the first direction X, so that the shape of the intermediate connection printing hole 1213 is rectangular, and the first connection printing hole 1211 and the second connection printing hole 1212 can have the same shape, both rectangular, but the length of the first connection printing hole 1211 and the second connection printing hole 1212 in the first direction X is not equal, so that the overall shape of the connection printing area 121 can be inverted H-shaped. In this way, the effective connection of the connection structure 222 with the auxiliary grid 221 can also be guaranteed, and the loss of paste can be reduced, thereby facilitating cost reduction.

[0141] In another example, the width of the intermediate connection printing hole 1213 in the first direction X can be smaller than the shortest length of the first connection printing hole 1211 and the second connection printing hole 1212 in the first direction X, but the intermediate connection printing hole 1213 is connected between the first connection printing area 121 and the second connection printing area 121 in an inclined manner, so that the intermediate connection printing area 121 presents a parallelogram, and the first connection printing hole 1211 and the second connection printing hole 1212 can have the same shape and size, so that the overall shape of the connection printing area 121 is N-shaped, which can also enable the connection structure 222 formed through the connection printing area 121 to be effectively connected between the auxiliary grids 221 located on both sides of the fracture 221a, and the loss of paste can be reduced.

[0142] Of course, in other embodiments, the width of the intermediate connection printing hole 1213 in the first direction X can be gradually changed from the first connection printing hole 1211 to the second connection printing hole 1212, for example, first decreasing and then increasing, and the overall shape of the connection printing area 121 is inverted 8-shaped.

[0143] Preferably, the connecting printing area 121 is shaped as H-shaped, which not only facilitates the processing of the shape from the perspective of the second screen 12, but also facilitates the connection of the formed connecting structure 222 with the sub-busbar 221 from the perspective of printing, thereby reducing the loss of paste.

[0144] It should be further noted that the connecting position of the intermediate connecting printing area 121 in the connecting printing area 121 in the above-mentioned various examples can be offset in the second direction Y, as long as the formed intermediate connecting line 2223 is connected between the first connecting line 2221 and the second connecting line 2222, so that the sub-busbar 221 can ensure current transmission, which can effectively improve the flexibility of the design of the connecting printing area 121.

[0145] It can be understood that the screen structure 10 in the embodiments of the present application can be applied to 0BB (0 Busbar, no main busbar), MBB (Multi Busbar, multi-main busbar), SMBB (Super Multi Busbar, super multi-main busbar), etc. The 0BB technology is used to cancel the main busbar 223 in the printing process, and a thinner solder strip is used to directly replace and connect the sub-busbar 221 to collect and export the current, which can significantly reduce the metal shading area of the surface of the solar cell semi-finished product 21, increase the light receiving area, and thus improve the power generation efficiency of the solar cell 20. The MBB and SMBB technologies are mainly used to collect the current of the sub-busbar 221 through the main busbar 223 and weld the solder strip to export the current.

[0146] When the 0BB technology is used, that is, the solar cell 20 without the main busbar 223, as an example, the second screen 12 is not provided with a main busbar printing area 122, and in the second direction Y, a spacing area 111b is formed between adjacent two sub-busbar printing holes 111a, the length of the sub-busbar printing hole 111a in the second direction Y is D2, the width of the spacing area 111b in the second direction Y is D3, the number of the spacing area 111b is M, the opening rate of the first screen 11 is F, F=D2(M+1) / [D2(M+1)+D3*M], 90%≤F<100%. For example, the width of the spacing area 111b is designed to be 0.2 mm, the number is 17, and the total length of all the sub-busbar printing holes 111a and the spacing areas 111b on each sub-busbar printing area 111 is 208.6 mm, and the opening rate is (208.6-0.2*17) / 208.6*100%=98.37%.

[0147] When the main grid printing area 122 is not arranged on the second screen 12 to form the main grid 223 of the solar cell 20, by limiting the length of the auxiliary grid printing hole 111a, the width of the interval area 111b, and the number of the interval area 111b, the proportion of the size of the interval area 111b to the total length of the auxiliary grid printing area 111 can be controlled. On the basis of being able to guarantee the smooth and uniform infiltration of the paste, the segmented arrangement of the auxiliary grid printing area 111 can be made more reasonable, and the structural stability of the first screen 11 can be effectively guaranteed.

[0148] Since the 0BB technology is to directly weld the solder strip with the thinner auxiliary grid 221, during welding, problems such as welding grid breakage, empty welding, and false welding are prone to occur. Based on this, in some embodiments, the second screen 12 can be provided with a main grid printing area 122, and the main grid printing area 122 is configured to form a main grid 223 on the solar cell semi-finished product 21. Referring to Figure 6 By further arranging the main grid printing area 122 on the second screen 12 to form the main grid 223 on the solar cell semi-finished product 21, the current formed by the auxiliary grid 221 collecting carriers is converged on the main grid 223, and the current is led out by welding the solder strip with the main grid 223, which effectively guarantees the welding area of the solder strip and the main grid 223.

[0149] Optionally, the main grid printing area 122 is arranged in the second direction Y and is spaced apart from the connecting printing area 121, and / or the connecting printing area 121 is at least partially in communication with the main grid printing area 122.

[0150] In an example, the main grid printing area 122 is arranged in the second direction Y and is spaced apart from the connecting printing area 121. Since the connecting structure 222 formed by the connecting printing area 121 is located at the break 221a of the auxiliary grid 221, such arrangement can make the break 221a on the solar cell semi-finished product 21 and the main grid 223 also be spaced apart, and the connecting structure 222 located at the break 221a is spaced apart from the main grid 223.

[0151] In this way, the break 221a and the main grid 223 do not affect each other. By arranging the connecting structure 222 at the break 221a and connecting between the auxiliary grids 221 located on both sides of the break 221a, the current can be transmitted through the auxiliary grid 221, so that the current can normally converge on the main grid 223.

[0152] In another example, the connecting printing area 121 is at least partially in communication with the main grid printing area 122. Since the connecting structure 222 formed by the connecting printing area 121 is located at the break 221a of the auxiliary grid 221, such arrangement makes the main grid 223 intersect with the break 221a of the auxiliary grid 221. At this time, the connecting structure 222 located at the break 221a is also connected to the main grid 223.

[0153] In this way, the connection structure 222 at the break 221a can be used to strengthen the connection between the main grid 223 and the auxiliary grid 221. However, it should be noted that this way puts requirements on the size of the connection structure 222. Specifically, since the connection structure 222 is printed synchronously with the main grid 223, the line height of the connection structure 222 formed by the paste used to print the main grid 223 is low, and the situation of broken grid after soldering may occur.

[0154] In another example, the main grid printing area 122 is spaced apart from a part of the connection printing area 121 in the second direction Y, and another part of the connection printing area 121 at least partially communicates with the main grid printing area 122, i.e., a part of the break 221a on the solar cell semi-finished product 21 is spaced apart from the main grid 223, and another part of the break 221a intersects with the main grid 223. It can be understood that in this example, the connection structure 222 formed by the connection printing area 121 spaced apart from the main grid printing area 122 can be the same as or different from the connection structure 222 formed by the connection printing area 121 communicating with the main grid printing area 122. For example, the connection printing area 121 spaced apart from the main grid printing area 122, since the connection structure 222 formed thereby is used to connect the auxiliary grid 221 with the break 221a, as long as the connection is met, the size (width, length, height, etc.) of the corresponding connection printing area 121 can be set smaller on the basis of meeting the connection, thereby reducing the loss of paste. However, the connection printing area 121 communicating with the main grid printing area 122, since it needs to meet the connection of the broken auxiliary grid 221 and also meet the current convergence and soldering requirements at this position, the size of the connection printing area 121 needs to be set larger, so that the size of the connection structure 222 formed thereby meets the above requirements, thereby avoiding the situation of broken grid due to the reaction of the solder strip with the conductive metal powder (such as silver powder) contained in the auxiliary grid 221 during soldering.

[0155] For example, the main grid printing area 122 can be three, and the connection printing area 121 can be two columns, one of which is located between the two columns of main grid printing areas 122, and the other of which at least partially communicates with the last column of main grid printing areas 122. Correspondingly, the main grid 223 formed thereby is three, and the connection structure 222 formed thereby is two columns, one of which is located between the two main grids 223, and the other of which is located on the last main grid 223.

[0156] In some possible implementation manners, the number of the main grid printing areas 122 is N, and the number of the interval areas 111b between two adjacent sub-grid printing holes 111a in the second direction Y is M, and 1 / 10N≤M≤20N; wherein N is an integer and N≥1, and M is an integer. Optionally, the number of the interval areas 111b can be 1N≤M≤20N, 5N≤M≤20N, or 10N≤M≤20N, and the like. For example, when the number of the main grid printing areas 122 is 10, the number of the interval areas 111b is 1≤M≤200, for example, 10, 20, or 30, and the like. By establishing a relationship between the number of the main grid printing areas 122 on the second screen 12 and the number of the interval areas 111b on the first screen 11, that is, a relationship between the number of the main grids 223 formed on the solar cell semi-finished product 21 and the number of the broken parts 221a, the number of the main grids 223 can be reduced, the amount of paste can be reduced, and the light shielding area can be reduced on the basis of taking into account the structural strength of the first screen 11 and realizing the continuous connection of the sub-grids 221.

[0157] Optionally, the main grid printing area 122 includes a plurality of main grid printing areas 122, and the plurality of main grid printing areas 122 are arranged at intervals in the second direction Y. When the main grid printing area 122 is arranged at intervals with the connection printing area 121 in the second direction Y, the connection printing area 121 is located between two adjacent main grid printing areas 122. Because the number of the main grids 223 can be reasonably increased to reduce the transmission distance of the sub-grid 221, the plurality of main grid printing areas 122 are arranged to form a plurality of main grids 223 on the solar cell semi-finished product 21, so that the distance between the two main grids 223 connected in series is shortened, thereby reducing the grid line transmission resistance and the series resistance, and thus the photoelectric conversion efficiency is improved.

[0158] In the embodiment of the present application, the SMBB technology can be used, and the number of the main grid printing areas 122 can be 16 to 26. For example, the number of the main grid printing areas 122 is 16, 18, 22, or 24, and a larger number of main grids 223 with smaller intervals can be obtained.

[0159] It should be noted that the auxiliary grid 221 is mainly used for collecting current. In order to make the connection printing area 121 located between the two adjacent main grid printing areas 122, that is, the break 221a is located between the two adjacent main grids 223, so that each main auxiliary grid 221 becomes an independent area. In the process of laser-induced sintering, the surface of the solar cell 20 needs to be powered on, and then laser-induced sintering is performed. During the entire process, if there is a break 221a between the auxiliary grids 221, the entire cell cannot be powered on, which makes the process unable to proceed. In addition, the IV and EL testing machines used in the production line are usually probes, and the probe pressing position is mainly on the main grid 223, and not every main grid 223 has it, so it will cause the current production IV and EL testing machine, laser-induced sintering equipment also cannot be used, and these devices need to be modified. Therefore, under the connection effect of the connection structure 222, the power-on condition of the laser-induced sintering can be improved, the current transmission mode can be improved, and the universality of the current testing equipment can be achieved without modification.

[0160] In some embodiments, referring to Figure 6 When the main grid printing area 122 is arranged in the second direction Y and spaced apart from the connection printing area 121, the second screen 12 further comprises a main grid lap printing area 123, which is at least partially located on the main grid printing area 122 and in communication with the main grid printing area 122. The main grid lap printing area 123 is configured to form a main grid lap structure 224 at the intersection of the main grid 223 and the auxiliary grid 221 on the solar cell semi-finished product 21. In this way, the main grid lap structure 224 at the intersection of the main grid 223 and the auxiliary grid 221 is formed by the main grid lap printing area 123 on the second screen 12, which can be used to collect the photoelectric current generated by the solar cell 20 when it is exposed to light. In addition, the connection between the main grid 223 and the auxiliary grid 221 can be strengthened, which further ensures that the main grid 223 and the auxiliary grid 221 have good contact and reduces metal compound, effectively reduces metal resistance, improves current transmission, and thus improves cell efficiency. At the same time, the main grid lap structure 224 is formed on the second screen 12, which will not affect the structural strength of the first screen 11 due to the opening on the first screen 11, thereby greatly improving the service life of the first screen 11.

[0161] Since the main grid lap printing area 123 is arranged on the second screen 12, the main grid lap structure 224 is printed synchronously with the main grid 223. Compared with the synchronous printing mode of the auxiliary grid 221, the height of the main grid lap structure 224 is reduced, for example, from 7 μm to 4 μm, which greatly increases the risk of broken grid in the subsequent soldering process. In addition, the material used in the soldering process will react with the silver in the main grid 223 and the auxiliary grid 221, which will cause the silver at the intersection of the main grid 223 and the auxiliary grid 221 to be reacted and broken.

[0162] Based on the above problems, in some possible embodiments, referring to Figures 3 to 7 The substrate 110 is further provided with a sub-grid lap printing area 112, which is at least partially located on the sub-grid printing area 111 and communicates with the sub-grid printing hole 111a. The sub-grid lap printing area 112 is configured to form a sub-grid lap structure 225 on the solar cell semi-finished product 21, and the sub-grid lap structure 225 is at least partially overlapped with the main-grid lap structure 224. By printing the main-grid lap structure 224 and the sub-grid lap structure 225 respectively when printing the main grid 223 and the sub grid 221, and arranging them to be at least partially overlapped, the height of the lap structure at the intersection of the main grid 223 and the sub grid 221 can be further increased, which can reduce the risk of grid breakage caused by the reduction of the height of the lap structure at the intersection of the main grid 223 and the sub grid 221 due to low wet weight, thereby improving the welding effect.

[0163] Optionally, the main-grid lap structure 224 is wrapped in the sub-grid lap structure 225, that is, the projection of the sub-grid lap structure 225 on the solar cell semi-finished product 21 falls within the projection range of the main-grid lap structure 224 on the solar cell semi-finished product 21. Alternatively, the sub-grid lap structure 225 is wrapped in the main-grid lap structure 224, that is, the projection of the main-grid lap structure 224 on the solar cell semi-finished product 21 falls within the projection range of the sub-grid lap structure 225 on the solar cell semi-finished product 21.

[0164] It can be understood that by designing the size and position of the sub-grid lap printing area 112 on the substrate 110 and the main-grid lap printing area 123 on the second screen 12, the overlap degree of the formed main-grid lap structure 224 and sub-grid lap structure 225 described above can be controlled. By setting the main-grid lap structure 224 wrapped in the sub-grid lap structure 225 or the sub-grid lap structure 225 wrapped in the main-grid lap structure 224, on the one hand, it can make the lap structure area formed by overlapping larger, which means that there is a larger area with higher height, thereby more conducive to meeting the welding requirements; on the other hand, since the paste will spread to a certain extent after printing, such a wrapped form is conducive to the appearance of the appearance.

[0165] Referring to Figure 7 and Figure 8 When the main-grid lap structure 224 is wrapped in the sub-grid lap structure 225, the maximum width T1 of the main-grid lap printing area 123 in the first direction X is 30 μm to 80 μm. Optionally, T1 can be 40 μm to 70 μm, 40 μm to 60 μm, or 40 μm to 50 μm, etc., for example, it can be 50 μm, 60 μm, or 70 μm, etc.

[0166] The minimum width T2 of the main grid overlap printing area 123 in the first direction X is 13 μm to 80 μm. Optionally, T2 can be 13 μm to 25 μm, 25 μm to 45 μm, 45 μm to 60 μm, or 60 μm to 80 μm, etc., for example, it can be 15 μm, 25 μm, 40 μm, 60 μm, or 80 μm, etc.

[0167] The length T3 of the main grid overlap printing area 123 in the second direction Y is 0.6 mm to 1.6 mm. Optionally, T3 can be 0.6 mm to 1.4 mm, 0.6 mm to 1.2 mm, or 0.6 mm to 1.0 mm, etc., for example, it can be 0.7 mm, 1.0 mm, or 1.3 mm, etc.

[0168] The maximum width T4 of the sub-grid overlap printing area 112 in the first direction X is 15 μm to 70 μm. Optionally, T4 can be 15 μm to 60 μm, 15 μm to 50 μm, or 15 μm to 40 μm, etc., for example, it can be 45 μm, 55 μm, or 65 μm, etc.

[0169] The minimum width T5 of the sub-grid overlap printing area 112 in the first direction X is 10 μm to 70 μm. Optionally, T5 can be 10 μm to 20 μm, 10 μm to 30 μm, or 15 μm to 30 μm, etc., for example, it can be 16 μm, 20 μm, or 24 μm, etc.

[0170] The length T6 of the sub-grid overlap printing area 112 in the second direction Y is 0.5 mm to 1.5 mm. Optionally, T6 can be 0.5 mm to 1.3 mm, 0.5 mm to 1.1 mm, or 0.5 mm to 0.8 mm, etc., for example, it can be 0.6 mm, 0.8 mm, or 1.2 mm, etc.

[0171] When the main grid overlap structure 224 is coated on the sub-grid overlap structure 225, by limiting the size of the main grid overlap printing area 123 and the sub-grid overlap printing area 112 to a reasonable range, it is possible to prevent the printing from causing the grid to be broken from the main grid 223 to the sub-grid due to the large difference in width and height, while ensuring sufficient area to meet the welding, preventing the molten tin from melting the sub-grid 221 after welding, causing the grid to be broken.

[0172] It can be understood that the width of the main grid lap joint structure 224 and the auxiliary grid lap joint structure 225 gradually changes in the second direction Y extension, and the control of the minimum width can ensure the stable connection of the auxiliary grid 221b and the main grid 223, avoid breaking, and the control of the maximum width can make the area larger for collecting current, so that the conduction current converges to the maximum, so as to reduce the conduction resistance, thereby facilitating to provide effective contact and stable transmission of current. At the same time, the size of the main grid lap joint printing area 224 is set to be compatible with the size of the auxiliary grid lap joint printing area 112, so that when the auxiliary grid lap joint structure 225 falls within the range of the main grid lap joint structure 224, a certain offset reserve amount can be provided, avoiding the case that the overall appearance effect of the lap joint structure is poor.

[0173] Correspondingly, when the auxiliary grid lap joint structure 225 is wrapped in the main grid lap joint structure 224, the maximum width T1 of the main grid lap joint printing area 123 in the first direction X is 15 μm-70 μm. Alternatively, T1 can be 15 μm-60 μm, 15 μm-50 μm, or 15 μm-40 μm, etc., for example, it can be 20 μm, 30 μm, or 60 μm, etc.

[0174] The minimum width T2 of the main grid lap joint printing area 123 in the first direction X is 10 μm-70 μm. Alternatively, T2 can be 10 μm-40 μm, 10 μm-50 μm, or 10 μm-60 μm, etc., for example, it can be 20 μm, 30 μm, or 40 μm, etc.

[0175] The length T3 of the main grid lap joint printing area 123 in the second direction Y is 0.5 mm-1.5 mm. Alternatively, T3 can be 0.5 mm-1.3 mm, 0.5 mm-1.1 mm, or 0.5 mm-0.8 mm, etc., for example, it can be 0.6 mm, 0.8 mm, or 1.2 mm, etc.

[0176] The maximum width T4 of the auxiliary grid lap joint printing area 112 in the first direction X is 30 μm-80 μm. Alternatively, T4 can be 30 μm-70 μm, 30 μm-60 μm, or 30 μm-50 μm, etc., for example, it can be 40 μm, 60 μm, or 70 μm, etc.

[0177] The minimum width T5 of the auxiliary grid lap joint printing area 112 in the first direction X is 13 μm-80 μm. Alternatively, T5 can be 13 μm-23 μm, 13 μm-40 μm, or 13 μm-60 μm, etc., for example, it can be 20 μm, 40 μm, or 60 μm, etc.

[0178] The length T6 of the sub-grid overlap printing area 112 in the second direction Y is 0.6mm-1.6mm. Optionally, T6 can be 0.6mm-1.4mm, 0.6mm-1.2mm, or 0.6mm-1.0mm, etc., for example, it can be 0.7mm, 1.0mm, or 1.3mm, etc.

[0179] When the sub-grid overlap structure 225 is wrapped in the main-grid overlap structure 224, by limiting the size of the sub-grid overlap printing area 112 and the main-grid overlap printing area 123 to a reasonable range, it is possible to prevent the printing from causing the main grid 223 to the fine grid to fall off due to the large difference in width and height, while ensuring sufficient area to meet the welding, preventing the molten tin from melting after welding to cause the sub-grid 221 to break down and cause the phenomenon of broken grid.

[0180] It can be understood that the width of the main-grid overlap structure 224 and the sub-grid overlap structure 225 gradually changes in the second direction Y, and the control of the minimum width can ensure the stable connection of the sub-grid 221b and the main grid 223, avoiding breakage, and the control of the maximum width can make the area larger for collecting current, so that the current is concentrated to the maximum, achieving the purpose of reducing the conduction resistance, thereby facilitating effective contact and stable transmission of current. At the same time, the size of the main-grid overlap printing area is set to be compatible with the size of the sub-grid overlap printing area 112, so that when the sub-grid overlap structure 225 falls within the range of the main-grid overlap structure 224, it can have a certain offset reserve, avoiding the case that the overall appearance of the overlap structure is poor.

[0181] Referring to Figures 9 to 11 In a second aspect, the present application also discloses a screen structure 10, which can include a first screen 11 and a second screen 12. The first screen 11 can be provided with a plurality of sub-grid printing areas 111, which are arranged at intervals along a first direction X and extend along a second direction Y. The sub-grid printing area 111 can be used to form a sub-grid 221 on a solar cell semi-finished product 21 during printing. The first direction X intersects the second direction Y.

[0182] The second screen 12 can be provided with a main-grid printing area 122, which can be used to form a main grid 223 during printing of the solar cell semi-finished product 21.

[0183] Optionally, the first screen 11 can further be provided with a sub-grid overlap printing area 112, and the second screen 12 can further be provided with a main-grid overlap printing area 123. The sub-grid overlap printing area 112 is at least partially located on the sub-grid printing area 111 and communicates with the sub-grid printing holes 111a, and is configured to form a sub-grid overlap structure 225 on the solar cell semi-finished product 21. The main-grid overlap printing area 123 is at least partially located on the main-grid printing area 122 and communicates with the main-grid printing area 122, and is configured to form a main-grid overlap structure 224 at the intersection of the main-grid 223 and the sub-grid 221 on the solar cell semi-finished product 21, and the main-grid overlap structure 224 is at least partially overlapped with the sub-grid overlap structure 225. In this way, the height of the overlap structure at the intersection of the main-grid 223 and the sub-grid 221 is increased, which can reduce the risk of grid breakage due to the decrease in the height of the overlap structure at the intersection of the main-grid 223 and the sub-grid 221 caused by low wet weight, thereby improving the welding effect.

[0184] It can be understood that the sub-grid printing area 111 on the first screen 11 of the screen structure 10 can further include a plurality of sub-grid printing holes 111a, and the plurality of sub-grid printing holes 111a are spaced apart in the second direction Y. The plurality of sub-grid printing holes 111a of each sub-grid printing area 111 are configured to form a sub-grid 221 with a break 221a on the solar cell semi-finished product 21, so as to print a sub-grid 221 with a narrower line width, obtain a solar cell 20 with low wet weight, and reduce the occurrence of printing defects such as grid breakage, ghosting, and poor flatness, while improving the structural stability of the first screen 11, thereby facilitating the improvement of the service life of the first screen 11.

[0185] Correspondingly, the second screen 12 can further be provided with a connection printing area 121, and the connection printing area 121 is configured to form a connection structure 222 at the break 221a on the solar cell semi-finished product 21. The connection structure 222 is configured to connect the sub-grids 221 on both sides of the break 221a in the second direction Y.

[0186] It can be understood that the structures of the sub-grid printing area 111, the sub-grid printing hole 111a, the main-grid printing area 122, the connection printing area 121, the sub-grid overlap printing area 112, and the main-grid overlap printing area 123 can refer to the description of the first aspect described above, and will not be described here.

[0187] In a third aspect, the embodiments of the present application further disclose a solar cell 20, which can refer to Figures 12 to 13 The solar cell 20 can include a solar cell semi-finished product 21 and an electrode structure 22.

[0188] In the present application, the electrode structure 22 can be arranged on the front surface of the solar cell semi-finished product 21, on the back surface of the solar cell semi-finished product 21, or on both surfaces.

[0189] In the present application, the electrode structure 22 is arranged on the front surface of the solar cell semi-finished product 21, that is, the electrode structure 22 of the present application is a front electrode. The following will be described by taking the electrode structure 22 arranged on the front surface of the solar cell semi-finished product 21 as an example.

[0190] In some embodiments, the electrode structure 22 can include a plurality of sub-grids 221, and the plurality of sub-grids 221 are arranged at intervals along the first direction X, and each sub-grid 221 extends along the second direction Y.

[0191] Since the sub-grid 221 can achieve the function of effective current transmission while obtaining a solar cell with low wet weight, reducing surface shading and conductive paste consumption, and reducing the overall solar cell 20 manufacturing cost, therefore,

[0192] In some embodiments, each sub-grid 221 includes a plurality of sub-sub-grids 221b, and the plurality of sub-sub-grids 221b are arranged at intervals along the second direction Y to form a break 221a between adjacent two sub-sub-grids 221b. In this way, the surface shading and conductive paste consumption can be reduced without affecting the current collection of the sub-grid 221.

[0193] In order not to affect the transmission of current, in some embodiments, the electrode structure 22 can further include a connection structure 222, the connection structure 222 is located at the break 221a, and the connection structure 222 is connected between adjacent two sub-sub-grids 221b along the second direction Y. By arranging the connection structure 222 at the break 221a and connecting between the sub-grids 221 on both sides of the break 221a, the current can be transmitted through the sub-grid 221, realizing the current transmission function of the sub-grid 221.

[0194] In some embodiments, referring to Figure 14 The width W1 of the sub-grid 221 along the first direction X is 4 μm to 30 μm. Alternatively, W1 can be 4 μm to 20 μm, for example, 8 μm, 10 μm, or 14 μm, etc.; or W1 can be 4 μm to 10 μm, for example, 5 μm, 7 μm, or 9 μm, etc. By limiting the range of the width W1 of the sub-grid 221 along the first direction X, the sub-grid 221 is narrowed, and a solar cell 20 with low wet weight is obtained, reducing the manufacturing cost of the solar cell 20.

[0195] In some embodiments, the height H of the cross section of the sub-grid 221 is 1-10 μm. Optionally, the height H can be 1-8 μm, 1-6 μm, or 1-4 μm, for example, 2 μm, 6 μm, or 8 μm. By limiting the height H of the cross section of the sub-grid 221, the cross-sectional area of the sub-grid 221 can be better controlled, so that the sub-grid 221 has better current transmission capability. If the height of the cross section is too low, the contact resistance and line resistance of the sub-grid 221 will increase, ultimately affecting the transmission capability of the solar cell 20.

[0196] In some embodiments, the smoothness factor of the sub-grid 221 in the height direction is less than or equal to 1. Optionally, the smoothness factor can be 0.01-1, 0.01-0.8, or 0.1-0.3, for example, 0.02, 0.06, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1.0. In combination with the above-mentioned height H of the cross section of the sub-grid 221, the sub-grid 221 has better smoothness, and the height profile curve of the sub-grid 221 is relatively smooth. Thus, the smaller the resistance of the sub-grid 221, the less the loss in the current transmission process, thereby improving the output power and efficiency of the solar cell 20. In addition, the relatively flat sub-grid 221 can ensure smoother current transmission, reduce the loss in the current transmission process, and further improve the performance of the solar cell 20. Figure 21 and Figure 22 As can be seen, the sub-grid 221 printed by the first screen 11 of the present application can have better smoothness, and the height profile curve of the sub-grid 221 is relatively smooth. Thus, the smaller the resistance of the sub-grid 221, the less the loss in the current transmission process, thereby improving the output power and efficiency of the solar cell 20. In addition, the relatively flat sub-grid 221 can ensure smoother current transmission, reduce the loss in the current transmission process, and further improve the performance of the solar cell 20.

[0197] In some embodiments, the connection structure 222 can be a rectangular connection structure 222, which is filled with paste in the area thereof, and the rectangular connection structure 222 is connected between the sub-sub-grids 221b on both sides of the break 221a, so that each sub-grid 221 extends as an uninterrupted grid line in the second direction Y.

[0198] Of course, in other embodiments, the connection structure 222 can also be, for example, a circular, circular-like, or other polygonal hole (for example, triangular, pentagonal, or hexagonal, etc.).

[0199] In addition, in some embodiments, referring to Figure 15 The connection structure 222 can include a first connection line 2221, a second connection line 2222, and an intermediate connection line 2223. The first connection line 2221 is connected to one of the sub-sub-grids 221b on one side of the break 221a in the second direction Y, the second connection line 2222 is connected to another of the sub-sub-grids 221b on the other side of the break 221a in the second direction Y, and the intermediate connection line 2223 is connected between the first connection line 2221 and the second connection line 2222.

[0200] Compared with the relatively regular rectangular overall shape of the connection structure 222, in this way, the sub-sub-grid 221b located on one side of the fracture 221a is connected by the first connecting line 2221, the sub-sub-grid 221b located on the other side of the fracture 221a is connected by the second connecting line 2222, and the first connecting line 2221 and the second connecting line 2222 are connected by the intermediate connecting line 2223, so that the sub-grid 221 with the fracture 221a can form a continuous sub-grid 221, thereby achieving the current transmission function, reducing the amount of paste used, reducing the wet weight of the printed paste, and reducing the manufacturing cost of the solar cell 20.

[0201] It should be noted that the first connecting line 2221 and the second connecting line 2222 can extend in the first direction X. Among them, the shapes of the first connecting line 2221, the second connecting line 2222 and the intermediate connecting line 2223 can be different, and the width of the intermediate connecting line 2223 in the first direction X can be smaller than the width of the first connecting line 2221 and the second connecting line 2222 in the first direction X, or the width of the intermediate connecting line 2223 in the first direction X is gradually changed from the first connecting line 2221 to the second connecting line 2222, so that the overall shape of the connection structure 222 is non-rectangular, non-trapezoidal or other shapes with larger area, thereby avoiding forming a connection structure 222 on the solar cell semi-finished product 21 that consumes too much paste, increases the shading area, and affects the shading efficiency of the solar cell 20.

[0202] In some possible embodiments, the width of the sub-grid 221 in the first direction X is W1, and the shortest length of the first connecting line 2221 and the second connecting line 2222 in the first direction X is W2, W2≥W1. By limiting the length of the first connecting line 2221 and the second connecting line 2222 in the first direction X to be greater than the width of the sub-grid 221 in the first direction X, that is, a large enough connection area can be provided to stably connect the sub-sub-grid 221b, and during the formation of the connection structure 222, the connection offset of the first connecting line 2221 and the second connecting line 2222 can be controlled, and the product defects caused by the offset can be improved.

[0203] In some embodiments, the length W3 of the connection structure 222 in the second direction Y is 0.05mm-1.6mm. Alternatively, W3 can be 0.05mm-1.3mm, 0.05mm-1.0mm or 0.05mm-0.8mm, etc., for example, it can be 0.2mm, 0.6mm or 1.0mm, etc. Since the connection structure 222 needs to be located at the fracture 221a and can be connected between the grid lines on both sides of the fracture 221a, by limiting the overall length of the connection structure 222, the connection structure 222 has an offset allowance in the second direction Y, which reduces the printing difficulty, thereby reducing the printing defects of the broken grid caused by the offset.

[0204] In some embodiments, the shortest length W2 of the first connection line 2221 and the second connection line 2222 in the first direction X is 40 μm to 120 μm, which can be 40 μm to 100 μm, 40 μm to 80 μm, or 40 μm to 60 μm, or the like, for example, 50 μm, 70 μm, or 100 μm, or the like. By limiting the range of W2, a certain offset can be reserved in the first direction X when connected with the sub-sub-grid 221b, thereby reducing the printing difficulty.

[0205] It should be noted that the shortest length W2 of the first connection line 2221 and the second connection line 2222 in the first direction X means that the length of the first connection line 2221 and the second connection line 2222 in the first direction X can be equal, or the length of the first connection line 2221 in the first direction X is greater than the length of the second connection line 2222 in the first direction X, or the length of the first connection line 2221 in the first direction X is less than the length of the second connection line 2222 in the first direction X.

[0206] In some embodiments, the width W4 of the first connection line 2221 and the second connection line 2222 in the second direction Y is 2 μm to 60 μm. Alternatively, W4 can be 2 μm to 40 μm, 2 μm to 30 μm, or 2 μm to 20 μm, or the like, for example, 4 μm, 10 μm, or 20 μm, or the like. By limiting the range of W4, on the basis of being able to make the connection structure 222 connected to the sub-sub-grid 221b, the amount of paste used can be reduced when connected with the sub-sub-grid 221b.

[0207] In some embodiments, the width W5 of the intermediate connection line 2223 in the first direction X is 2 μm to 60 μm. Alternatively, W5 can be 2 μm to 40 μm, 2 μm to 30 μm, or 2 μm to 20 μm, or the like, for example, 4 μm, 10 μm, or 20 μm, or the like. By limiting the range of W5, while ensuring that the intermediate line is effectively connected between the first connection line 2221 and the second connection line 2222, the amount of paste used can be reduced, the wet weight can be reduced, and the light shielding area can be reduced.

[0208] In some embodiments, the shape of the connection structure 222 includes at least one of H type, N type, or inverted 8 type. By using the connection structure 222 with these shapes, on the basis of being able to ensure the effective connection between the connection structure 222 and the sub-sub-grid 221b located on both sides of the fracture 221a, the loss of paste can be reduced.

[0209] It can be understood that the shape of the connection structure 222 is substantially the same as the shape of the connection printing area 121 on the first screen 11, and the specific size is different, and the specific structure can refer to the shape of the connection printing area 121.

[0210] In one example, the width of the intermediate connecting line 2223 in the first direction X can be less than the shortest length of the first connecting line 2221 and the second connecting line 2222 in the first direction X, so that the shape of the intermediate connecting line 2223 is rectangular, and the first connecting line 2221 and the second connecting line 2222 can have the same shape and size, both rectangular, so that the overall shape of the connecting structure 222 is H-shaped. In this way, when the first connecting line 2221 and the second connecting line 2222 formed on the solar cell semi-finished product 21 are connected with the sub-grid 221, even if there is an offset error, the connection of the sub-grid 221b with the connecting line can be guaranteed, so that the connecting structure 222 can be effectively connected between the sub-grids 221b on both sides of the fracture 221a, and the loss of paste can be reduced, which is conducive to reducing the cost.

[0211] In another example, the width of the intermediate connecting line 2223 in the first direction X can be less than the shortest length of the first connecting line 2221 and the second connecting line 2222 in the first direction X, so that the shape of the intermediate connecting line 2223 is rectangular, and the first connecting line 2221 and the second connecting line 2222, both rectangular, the length of the first connecting line 2221 and the second connecting line 2222 in the first direction X can not be equal, so that the overall shape of the connecting structure 222 can be inverted H-shaped. In this way, the effective connection of the connecting structure 222 with the sub-grid 221 can also be guaranteed, and the loss of paste can be reduced, thereby facilitating cost reduction.

[0212] In another example, the width of the intermediate connecting line 2223 in the first direction X can be less than the shortest length of the first connecting line 2221 and the second connecting line 2222 in the first direction X, but the intermediate connecting structure 222 is connected between the first connecting structure 222 and the second connecting structure 222 in an inclined manner, so that the intermediate connecting structure 222 presents a parallelogram, and the first connecting line 2221 and the second connecting line 2222 can have the same shape and size, so that the overall shape of the connecting structure 222 is N-shaped, and the connecting structure 222 formed by the connecting structure 222 can be effectively connected between the sub-grids 221 on both sides of the fracture 221a, and the loss of paste can be reduced.

[0213] Of course, in other embodiments, the width of the intermediate connecting line 2223 in the first direction X is gradually changed from the first connecting line 2221 to the second connecting line 2222, for example, first decreasing and then increasing, and the overall shape of the connecting structure 222 is inverted 8-shaped.

[0214] Preferably, the shape of the connecting structure 222 is H-shaped, which is more conducive to guaranteeing the connection of the formed connecting structure 222 with the sub-grid 221, reducing the loss of paste, reducing the light shielding area, and thereby improving the conversion efficiency of the solar cell 20.

[0215] In the embodiments of the present application, the electrode structure 22 can be 0BB (0 Busbar, without main grid), MBB (Multi Busbar, multi-main grid 223), SMBB (Super Multi Busbar, super multi-main grid), etc. The 0BB technology is used to cancel the main grid 223 and use the solder strip to directly connect the sub-grid 221 to collect and export the current. In this way, the metal shading area of the solar cell semi-finished product 21 can be significantly reduced, the light receiving area is increased, and the power generation efficiency of the solar cell 20 is improved. The MBB and SMBB technologies are mainly used to collect the current of the sub-grid 221 through the main grid 223 and solder the solder strip to export the current.

[0216] Taking the solar cell 20 of the present application as an example of MBB or SMBB.

[0217] In some embodiments, the electrode structure 22 further includes a main grid 223 extending along the first direction X. By providing the main grid 223 on the solar cell semi-finished product 21, the current collected by the sub-grid 221 is converged to the main grid 223, and the current is exported through the soldering of the main grid 223 and the solder strip, thereby effectively ensuring the soldering area of the solder strip and the main grid 223.

[0218] That is, the electrode structure 22 can include a main grid 223 and a sub-grid 221, the main grid 223 extends along the first direction X, and the sub-grid 221 extends along the second direction Y. The main grid 223 and the sub-grid 221 intersect, so that the sub-grid 221 can converge the current to the main grid 223.

[0219] Optionally, in the case where the break 221a is formed on the sub-grid 221, the main grid 223 is spaced apart from the break 221a in the second direction Y, and / or the break 221a is located on the main grid 223.

[0220] It can be understood that, in one example, the main grid 223 is spaced apart from the break 221a in the second direction Y. Since the connecting structure 222 is located at the break 221a of the sub-grid 221, the connecting structure 222 located at the break 221a is spaced apart from the main grid 223 by such arrangement. In this way, the break 221a and the main grid 223 do not affect each other. By arranging the connecting structure 222 at the break 221a and connecting the sub-grids 221 on both sides of the break 221a, the current can be transmitted through the sub-grids 221, so that the current can be normally converged to the main grid 223.

[0221] In another example, referring to Figure 16In this way, the connection structure 222 at the break 221a can be used to strengthen the connection between the main grid 223 and the sub-grid 221, but it should be noted that this way puts requirements on the size of the connection structure 222. Specifically, since the connection structure 222 is printed synchronously with the main grid 223, the slurry used for printing the main grid 223 is used to form the connection structure 222, and the line height of the connection structure 222 is low, which is prone to cause the welding break.

[0222] In another example, the main grid 223 is spaced apart from a part of the break 221a in the second direction Y, and another part of the break 221a is located on the main grid 223. It can be understood that in this example, the connection structure 222 spaced apart from the main grid 223 can be the same as or different from the connection structure 222 located on the main grid 223. For example, the connection structure 222 spaced apart from the main grid 223 is used to connect the sub-grid 221 with the break 221a, as long as the connection is met, the size (width, length, height, etc.) of the corresponding connection structure 222 can be set smaller on the basis of meeting the connection, thereby reducing the loss of slurry, but the connection structure 222 located on the main grid 223 needs to meet the connection of the broken sub-grid 221b and the current convergence and welding requirements at this position, so the size of the connection structure 222 needs to be set larger to meet the above requirements, to avoid the break caused by the reaction of the solder strip and the silver contained in the sub-grid 221 during welding.

[0223] For example, the main grid 223 is three, and the connection structure 222 is two columns, one of which is located between the two main grids 223, and the other column of the connection structure 222 is located on the last main grid 223.

[0224] It should be noted that the auxiliary grid 221 is mainly used for collecting current. When the break 221a is arranged between the main grid 223, each main auxiliary grid 221 becomes an independent area. During the process of laser-induced sintering, the surface of the solar cell 20 needs to be powered on, and then laser-induced sintering is performed. During the entire process, if there is a break 221a between the auxiliary grid 221, the entire cell cannot be powered on, so that the process cannot be performed. In addition, the IV and EL test machines used in the production line are usually probes, and the probe pressing position is mainly on the main grid 223, and not every main grid 223 has it, so it will cause the current production IV and EL test machine cannot be used, and the equipment needs to be modified. Therefore, the main grid 223 is arranged on the electrode structure 22, and the connection structure 222 is arranged when the current collected by the auxiliary grid 221 needs to be converged. The connection structure 222 can improve the power-on condition of laser-induced sintering, improve the current transmission mode, and achieve the universality of not changing the current test equipment.

[0225] In some embodiments, the main grid 223 includes a plurality of main grids 223 arranged along the second direction Y. When the main grid 223 is arranged apart from the break 221a along the second direction Y, the break 221a is located between the two adjacent main grids 223. Since the number of main grids 223 is reasonably increased to reduce the transmission distance of the auxiliary grid 221, the distance between the two main grids 223 connected to the auxiliary grid 221 is shortened, thereby reducing the grid line transmission resistance and reducing the series resistance, thereby facilitating the improvement of photoelectric conversion efficiency.

[0226] It should be noted that when the break 221a is located between the two adjacent main grids 223, the number of breaks 221a can be multiple, that is, the auxiliary grid 221 located between the two main grids 223 has multiple breaks. The plurality of breaks 221a can be arranged apart along the second direction Y.

[0227] In the embodiments of the present application, the SMBB technology can be used, and the number of main grids 223 can be 16-26. For example, the number of main grid printing areas 122 is 16, 18, 22 or 24, and more number and smaller pitch of main grids 223 can be obtained. Of course, in other embodiments, the number of main grids 223 can also be other numbers, and the number of main grids 223 in the present embodiment is not limited, as long as it meets the needs of solar cells.

[0228] Since the lap joint state of the intersection of the main grid 223 and the auxiliary grid 221 will directly affect the collection and export of photo-generated carriers. When the lap joint of the two is poor due to disconnection or disconnection of the grid, the short-circuit current of the solar cell 20 will decrease significantly. Therefore, the lap joint structure is usually arranged at the intersection of the main grid 223 and the auxiliary grid 221.

[0229] It can be understood that when the breakage 221a is located on the main grid 223, the connection structure 222 at this time is equivalent to a lap joint structure, which connects the main grid 223 and the sub-grid 221 on the basis of connecting the sub-grids 221b capable of being located on both sides of the breakage 221a, so as to meet the collection and export of photo-generated carriers, but since the intersection of the main grid 223 and the sub-grid 221 at this time only has one layer of the connection structure 222, and the connection structure 222 is formed simultaneously with the main grid 223, it can not meet the welding requirement. Based on this, in the embodiments of the present application, the breakage 221a is preferably spaced apart from the main grid 223, so as to provide conditions for not only synchronously forming the main grid lap joint structure 224 when the main grid 223 is printed, but also synchronously forming the sub-grid lap joint structure 225 when the sub-grid 221 is printed, and overlapping the two.

[0230] In some embodiments, when the sub-grid 221 has the breakage 221a, and the main grid 223 is spaced apart from the breakage 221a in the second direction Y, the electrode structure 22 further comprises a main grid lap joint structure 224 connected to the main grid 223, and the main grid lap joint structure 224 is located at the intersection of the main grid 223 and the sub-grid 221b. In this way, by arranging the main grid lap joint structure 224 at the intersection of the main grid 223 and the sub-grid 221b, the main grid lap joint structure 224 can strengthen the connection between the main grid 223 and the sub-grid 221b, further reduce metal composites under the premise of ensuring that the main grid 223 has good contact with the sub-grid 221b, effectively reduce the metal resistance, improve the current transmission, and thus improve the battery efficiency. At the same time, the use of paste can be saved, and the cost can be reduced.

[0231] Since a layer of main grid lap joint structure 224 is separately arranged to realize the connection between the main grid 223 and the sub-grid 221b, the height of the main grid lap joint structure 224 will be reduced, which greatly increases the risk of welding the broken grid in the subsequent welding process.

[0232] Based on this, in some possible embodiments, referring to Figure 17 and Figure 18 , the electrode structure 22 further comprises a sub-grid lap joint structure 225 connected to the sub-grid 221b, and the sub-grid lap joint structure 225 and the main grid lap joint structure 224 are at least partially overlapped. By synchronously arranging the main grid lap joint structure 224 and the sub-grid lap joint structure 225 on the solar cell semi-finished product 21, the two are at least partially overlapped, which can further increase the height of the lap joint structure at the intersection of the main grid 223 and the sub-grid 221b, and can reduce the risk of broken grid caused by the low height of the lap joint structure at the intersection of the main grid 223 and the sub-grid 221b, thereby improving the welding effect.

[0233] Optionally, the main busbar overlap structure 224 is wrapped in the secondary busbar overlap structure 225, that is, the projection of the secondary busbar overlap structure 225 on the solar cell semi-finished product 21 falls within the projection range of the main busbar overlap structure 224 on the solar cell semi-finished product 21. Or, the main busbar overlap structure 224 is wrapped in the secondary busbar overlap structure 225, that is, the projection of the main busbar overlap structure 224 on the solar cell semi-finished product 21 falls within the projection range of the secondary busbar overlap structure 225 on the solar cell semi-finished product 21. By setting the main busbar overlap structure 224 wrapped in the secondary busbar overlap structure 225 or the secondary busbar overlap structure 225 wrapped in the main busbar overlap structure 224, on the one hand, the overlap structure area formed by overlapping can be made larger, which means that there is a larger area with a higher height, thereby more conducive to meeting the welding requirements; on the other hand, since the paste will have a certain diffusion after printing, such a wrapped form is conducive to the consistency of the appearance.

[0234] When the main busbar overlap structure 224 is wrapped in the secondary busbar overlap structure 225, the maximum width L1 of the main busbar overlap structure 224 in the first direction X is 35 μm-90 μm. Optionally, L1 can be 35 μm-80 μm, 35 μm-70 μm, 35 μm-60 μm, or 50 μm-90 μm, etc., for example, it can be 60 μm, 70 μm, or 80 μm, etc.

[0235] The minimum width L2 of the main busbar overlap structure 224 in the first direction X is 20 μm-90 μm. Optionally, L2 can be 20 μm-30 μm, 20 μm-50 μm, 20 μm-60 μm, or 20 μm-70 μm, etc., for example, it can be 30 μm, 50 μm, or 80 μm, etc.

[0236] The length L3 of the main busbar overlap structure 224 in the second direction Y is 0.65 mm-1.7 mm. Optionally, L3 can be 0.65 mm-1.5 mm, 0.65 mm-1.2 mm, or 0.65 mm-1.0 mm, etc., for example, it can be 0.7 mm, 1.0 mm, or 1.3 mm, etc.

[0237] The maximum width L4 of the secondary busbar overlap structure 225 in the first direction X is 20 μm-75 μm. Optionally, L4 can be 20 μm-60 μm, 20 μm-50 μm, 20 μm-40 μm, or 35 μm-75 μm, etc., for example, it can be 45 μm, 55 μm, or 65 μm, etc.

[0238] The minimum width L5 of the secondary busbar overlap structure 225 in the first direction X is 15 μm-75 μm. Optionally, L5 can be 5 μm-20 μm, 15 μm-30 μm, or 15 μm-50 μm, etc., for example, it can be 20 μm, 30 μm, or 50 μm, etc.

[0239] The length L6 of the sub-grid overlap structure 225 in the second direction Y is 0.55mm-1.6mm. Alternatively, L6 can be 0.55mm-1.4mm, 0.55mm-1.0mm, or 0.5mm-0.8mm, etc., for example, it can be 0.6mm, 0.8mm, or 1.2mm, etc.

[0240] When the main-grid overlap structure 224 is wrapped in the sub-grid overlap structure 225, by limiting the size of the main-grid overlap printing area 123 and the sub-grid overlap printing area 112 to a reasonable range, while preventing the printed main grid 223 from the sub-grid due to the huge difference in width and height during printing, it can prevent the printed grid from being broken, and at the same time, it can ensure sufficient area to meet the welding, prevent the molten tin from melting after welding to cause the sub-grid 221 to be broken, and prevent the phenomenon of broken grid from occurring.

[0241] It can be understood that the width of the main-grid overlap structure 224 and the sub-grid overlap structure 225 gradually changes in the second direction Y, and the control of the minimum width can ensure the stable connection of the sub-grid 221b and the main grid 223, avoid breaking, and the control of the maximum width can make the area larger for collecting current, so that the current converges to the maximum, and the purpose of reducing the conduction resistance is achieved, thereby facilitating the provision of effective contact and stable transmission of current. At the same time, the size of the main-grid overlap printing area is set to be compatible with the size of the sub-grid overlap printing area 112, so that when the sub-grid overlap structure 225 falls within the range of the main-grid overlap structure 224, a certain offset reserve can be provided, and the overall appearance of the overlap structure is not poor.

[0242] When the sub-grid overlap structure 225 is wrapped in the main-grid overlap structure 224, the maximum width L1 of the main-grid overlap structure 224 in the first direction X is 20μm-75μm. Alternatively, L1 can be 20μm-60μm, 20μm-50μm, 20μm-40μm, or 35μm-75μm, etc., for example, it can be 45μm, 55μm, or 65μm, etc.

[0243] The minimum width L2 of the main-grid overlap structure 224 in the first direction X is 15μm-75μm. Alternatively, L2 can be 5μm-20μm, 15μm-30μm, or 15μm-50μm, etc., for example, it can be 16μm, 17μm, or 18μm, etc.

[0244] The length L3 of the main-grid overlap structure 224 in the second direction Y is 0.55mm-1.6mm. Alternatively, L3 can be 0.55mm-1.4mm, 0.55mm-1.0mm, or 0.5mm-0.8mm, etc., for example, it can be 0.6mm, 0.8mm, or 1.2mm, etc.

[0245] The maximum width L4 of the sub-grid overlap structure 225 in the first direction X is 35-90 μm. Alternatively, L4 can be 35-80 μm, 35-70 μm, 35-60 μm, or 50-90 μm, for example, 60 μm, 70 μm, or 80 μm, etc.

[0246] The minimum width L5 of the sub-grid overlap structure 225 in the first direction X is 20-90 μm. Alternatively, L5 can be 20-30 μm, 20-50 μm, 20-60 μm, or 20-70 μm, etc., for example, 30 μm, 50 μm, or 80 μm, etc.

[0247] The length L6 of the sub-grid overlap structure 225 in the second direction Y is 0.65-1.7 mm. Alternatively, L6 can be 0.65-1.5 mm, 0.65-1.2 mm, or 0.65-1.0 mm, etc., for example, 0.7 mm, 1.0 mm, or 1.3 mm, etc.

[0248] When the sub-grid overlap structure 225 is wrapped around the main-grid overlap structure 224, by limiting the size of the sub-grid overlap printing area 112 and the main-grid overlap printing area 123 to a reasonable range, the printing can be prevented from being interrupted by the large difference in width and height between the main grid 223 and the sub-grid 221, while ensuring sufficient area to meet the welding requirements, and preventing the molten solder from melting the sub-grid 221 after welding to cause the grid interruption phenomenon.

[0249] In some other embodiments, when the sub-grid 221 is not provided with the break 221a and the battery structure is not provided with the connecting structure 222, the connection between the main grid 223 and the sub-grid 221 of the present application can also be provided with the main-grid overlap structure 224 and the sub-grid overlap structure 225 described above. The design of the main-grid overlap structure 224 and the sub-grid overlap structure 225 can be referred to the description above, which will not be repeated here.

[0250] In some embodiments, referring to Figure 13 The electrode structure 22 further includes a solder pad 226 and a fishhook 227. The solder pad 226 includes a first solder pad 226a and a second solder pad 226b. The first solder pad 226a is arranged at both ends of the main grid 223. The second solder pad 226b is arranged on the main grid 223 and located between the two first solder pads 226a. The fishhook 227 is arranged at both ends of each main grid 223 and connected to the first solder pad 226a. The area of the first solder pad 226a is larger than that of the second solder pad 226b, so that the first solder pad 226a is more conducive to connection with the fishhook 227.

[0251] Optionally, the first pad 226a and the second pad 226b can be in a strip structure extending along the second direction Y, of course, the first pad 226a and the second pad 226b can also be arranged obliquely, and the embodiments of the present application do not make a specific limitation in this regard.

[0252] It should be noted that the spear 227 in the embodiments of the present application can be printed synchronously when the main grid 223 is printed, and the spear 227 is arranged on the main grid 223. Since the silver paste solid content of the main grid 223 is generally low, the loss of the burn-through type silver paste can be reduced. Moreover, since the conductive paste solid content of the main grid 223 is lower than that of the sub-grid 221, and the low solid content is affected by the expansion of the solid content and the organic carrier thereof, under the condition of consistent ink transfer amount, the actual height after sintering is low, and then in the electrode printing structure of the present application, the structure 14 of the spear 227 is arranged on the main grid 223, which can also reduce the height of the spear 227, thereby reducing the passivation damage and improving the open circuit voltage, and then improving the photoelectric conversion efficiency.

[0253] The following will compare and illustrate the way of arranging the sub-grid printing area 111 on the substrate 110 and the way of forming the sub-grid printing area 111 by using the steel wire mesh plate.

[0254] Referring to FIGS. 11A, 11B and 11C, (a), (b) and (c) in FIG. 11A correspond to the three-dimensional topography diagram, the center line and the height profile curve diagram of the sub-grid 221 formed by arranging the sub-grid printing area 111 on the steel wire mesh plate at the cutting position 1. Figures 19 to 22 Referring to FIGS. 12A, 12B and 12C, (a), (b) and (c) in FIG. 12A correspond to the three-dimensional topography diagram, the center line and the height profile curve diagram of the sub-grid 221 formed by arranging the sub-grid printing area 111 on the steel wire mesh plate at the cutting position 2. Figure 19 Referring to FIGS. 13A, 13B and 13C, (a), (b) and (c) in FIG. 13A correspond to the three-dimensional topography diagram, the center line and the height profile curve diagram of the sub-grid 221 formed by arranging the sub-grid printing area 111 on the first screen plate 11 of the present application at the cutting position 1. Figure 20 Referring to FIGS. 14A, 14B and 14C, (a), (b) and (c) in FIG. 14A correspond to the three-dimensional topography diagram, the center line and the height profile curve diagram of the sub-grid 221 formed by arranging the sub-grid printing area 111 on the first screen plate 11 of the present application at the cutting position 2. Figure 21 Figure 22 Referring to FIGS. 13C and 14C, the height profile curve diagram shown in (c) is obtained by taking the center line in the width of the sub-grid as the selection line and referring to the surface of the solar cell as the reference, Referring to FIGS. 13C and 14C, the height profile curve diagram shown in (c) is obtained by taking the center line in the width of the sub-grid as the selection line and referring to the surface of the solar cell as the reference,

[0255] Referring to FIGS. 13C and 14C, the height profile curve diagram shown in (c) is obtained by taking the center line in the width of the sub-grid as the selection line and referring to the surface of the solar cell as the reference, Figures 19 to 22 Referring to FIGS. 13C and 14C, the height profile curve diagram shown in (c) is obtained by taking the center line in the width of the sub-grid as the selection line and referring to the surface of the solar cell as the reference, Figures 19 to 21 Referring to FIGS. 13C and 14C, the height profile curve diagram shown in (c) is obtained by taking the center line in the width of the sub-grid as the selection line and referring to the surface of the solar cell as the reference,

[0256] As can be seen from the figure, when printing the sub-grid 221 using a wire mesh screen, the paste exhibits severe concavity, causing the waveform of the height profile curve of the sub-grid 221 to dip at the corresponding positions, resulting in large fluctuations. In contrast, the sub-grid 221 formed using the sub-grid printing area 111 on the first screen 11 of this application has a smoother height profile curve. The sub-grid 221 exhibits a flatter shape in the height direction and a better narrowing effect in the width direction, resulting in superior overall smoothness.

[0257] Referring to Table 1, Table 1 shows any two positions (e.g., when printing with a wire mesh screen and when printing with the first screen of this application) of the formed sub-grid 221. Figures 19 to 22 The detection is performed on the sub-gate 221 area shown in the figure, and the center line passing through the width of the sub-gate 221 is selected as the selection line (see [reference]). Figures 19 to 22 In (b), the upper and lower straight lines represent the width profile of the sub-gate, and the straight line with the arrow is the selection line. The smoothing factor is calculated based on the height value of the sub-gate 221 obtained with the surface of the solar cell as the reference.

[0258] Specifically, refer to Figures 19 to 22 The height profile of the sub-grating 221 is measured using a 3D microscope at 50x magnification. Based on the height curve obtained from the height profile, height values ​​are derived from the height curve. For example, this application derives 1024 height point values, and calculates the variance of these 1024 height point values ​​using the concept of mathematical statistics. This variance is used to characterize the fluctuation of the height of the sub-grating 221, which is the smoothing factor described in this application. It should be noted that, depending on the system settings of different 3D microscope models, any number of height point values ​​can be derived. To reduce the impact of outlier data points on the error calculation of the smoothing factor, this application needs to remove outlier height point values. Outlier data points are defined as height data point values ​​that exceed 30% of the average height point values. For example, assuming the average of the 1024 height point values ​​is X... ave The outlier data point is X. i When |X i -X ave | / X ave The height data point value when it is >30% belongs to the abnormal height data point value described in this application.

[0259] When using a wire mesh screen for printing, the smoothing factors obtained at two different positions were 5.12 and 6.82, respectively. However, when using the first screen printing plate of this application, the smoothing factors obtained at the same two positions were 0.23 and 0.12, respectively. It is evident that the smoothing factor of the sub-grid formed when using the first screen printing plate is smaller. And combined with... Figures 19 to 22It can be obtained that the sub-grid printed by the first screen printing plate of the application is smoother and has a more even overall profile compared to the uneven sub-grid printed by a steel screen printing plate.

[0260] Table 1

[0261] Cut-off position 1 2 Wire mesh screen 5.12 6.82 First screen 0.23 0.12

[0262] See Figure 23 and Figure 24 wherein, Figure 23 (a), (b), (c) in FIG. 1 are respectively cross-sectional profile diagrams of the sub-grid 221 formed by a steel screen printing plate at different positions. Figure 24 (a), (b), (c) in FIG. 2 are respectively cross-sectional profile diagrams of the sub-grid 221 formed by the first screen printing plate 11 of the application at different positions. Wherein, Figure 23 and Figure 24 are cross-sectional profile diagrams of the sub-grid 221 printed with a width of 8 μm of the sub-grid printing hole 111a provided on the steel screen printing plate and the first screen printing plate 11.

[0263] Referring to Table 2, Table 2 shows comparative data of the width and height of the cross-sections taken at any three positions of the printed sub-grid 221 when printed by the steel screen printing plate and the first screen printing plate.

[0264] It can be seen that, considering the uncontrollable factors such as process fluctuation and slurry fluidity in actual printing, the actual width of the sub-grid formed by the steel screen printing plate is wider, and in comparison, the actual width of the sub-grid formed by the first screen printing plate is smaller than that of the sub-grid 221 formed by the steel screen printing plate, and a narrower sub-grid 221 line width can be obtained. In combination with Figures 19 to 22 It can be known that, since the steel screen printing plate is used for printing, the slurry infiltration at the position blocked by the steel wire is affected, resulting in uneven slurry infiltration at the position, causing a depression on the sub-grid 221 corresponding to the blocked position, and a protrusion at other positions, in a concave-convex uneven state, and causing greater fluctuation in the actual printing width. The way of printing the sub-grid 221 by the first screen printing plate 11 of the application can make the sub-grid printing more even, and can also make the difference between the design form and the actual form of the sub-grid 221 smaller, so that the printing process of the sub-grid 221 is more controllable, and is more conducive to narrowing the line width.

[0265] Table 2

[0266]

[0267] In a fourth aspect, the embodiments of the present application further include a photovoltaic module (not shown), which can include the solar cell 20 of the third aspect described above. Of course, it can also include a frame, photovoltaic glass, encapsulating material, etc., to collectively form the photovoltaic module, which is suitable for various outdoor environments, such as a roof, a building surface, etc., and is widely used in a solar photovoltaic system.

[0268] In a fifth aspect, the embodiments of the present application further disclose a method for printing the solar cell 20 using the screen structure 10 described above, which includes:

[0269] using the first screen 11 to print the solar cell semi-finished product 21 to obtain the sub-grid 221 with the fracture 221a;

[0270] using the second screen 12 to print the solar cell semi-finished product 21 to obtain the plurality of connection structures 222, so that the connection structures 222 are connected between the sub-grids 221 located on both sides of the fracture 221a.

[0271] Optionally, first, the second screen 12 can be used to print the solar cell semi-finished product 21 to obtain the plurality of connection structures 222; second, the first screen 11 is used again to print the solar cell semi-finished product 21 to obtain the sub-grid 221 with the fracture 221a, so that the connection structures 222 are located at the fracture 221a and connected between the sub-grids 221 located on both sides of the fracture 221a.

[0272] In the embodiments of the present application, the printing path of the electrode structure 22 can be: first printing the main grid 223 on the back of the solar cell semi-finished product 21, then printing the sub-grid 221 on the back, then printing the main grid 223 on the front, and finally printing the fine grid on the front. It can be understood that the sub-grid 221 is relatively thin, and if it is printed first, it is easy to scratch the sub-grid 221 when printing the main grid 223, which affects the current transmission.

[0273] It should be noted that the method for printing the solar cell using the screen structure described above in the embodiments of the present application is suitable for application in the field of solar cells, and can be applied in the preparation of various solar cells, such as bifacial cells, for example, heterojunction cells, passivated contact solar cells, etc.

[0274] The screen structure, the solar cell, the photovoltaic module, and the method for printing the solar cell disclosed in the embodiments of the present application are described in detail above, and specific examples are applied in this paper to describe the principles and implementation modes of the present application. The above description of the embodiments is only used to help understand the screen structure, the solar cell, the photovoltaic module, and the method for printing the solar cell and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, and the content of the specification should not be understood as a limitation of the present application.

Claims

1. A screen structure, characterized by, The application is applied to a solar cell, the solar cell comprises a solar cell semi-product, and the screen structure comprises: a first screen plate comprising a substrate provided with a plurality of sub-grid printing areas, the plurality of sub-grid printing areas are arranged at intervals in a first direction, each of the sub-grid printing areas comprises a plurality of sub-grid printing holes arranged at intervals in a second direction, and the plurality of sub-grid printing holes of each of the sub-grid printing areas are configured to form a sub-grid with a break on the solar cell semi-product; a second screen plate provided with a connecting printing area, the connecting printing area is configured to form a connecting structure on the solar cell semi-product at the break, and the connecting structure is configured to connect the sub-grids on both sides of the break in the second direction; wherein the first direction and the second direction intersect.

2. The screen structure of claim 1, wherein, The width D1 of the sub-grid printing hole in the first direction is 2 μm to 30 μm.

3. The screen structure of claim 1, wherein, In the second direction, a spacing area is formed between two adjacent sub-grid printing holes, the length D2 of the sub-grid printing hole in the second direction, and the width D3 of the spacing area in the second direction, and D2 / D3 is 35 to 240.

4. The screen structure of claim 3, wherein, The length D2 of the sub-grid printing hole in the second direction is 5 mm to 30 mm, and the width D3 of the spacing area in the second direction is 0.05 mm to 1.5 mm.

5. The screen structure of claim 1, wherein, The connecting printing area comprises a first connecting printing hole, a second connecting printing hole and an intermediate connecting printing hole, the intermediate connecting printing hole is communicated between the first connecting printing hole and the second connecting printing hole, the first connecting printing hole is configured to form a first connecting line on the solar cell semi-product, and the first connecting line is connected to the sub-grid on one side of the break in the second direction, the second connecting printing hole is configured to form a second connecting line on the solar cell semi-product, and the second connecting line is connected to the sub-grid on the other side of the break in the second direction, and the intermediate connecting printing hole is configured to form an intermediate connecting line on the solar cell semi-product, and the intermediate connecting line is connected between the first connecting line and the second connecting line.

6. The screen structure of claim 5, wherein, The width of the sub-grid printing hole in the first direction is D1, the shortest length of the first connecting printing hole and the second connecting printing hole in the first direction is D4, and D4≥D1.

7. The screen structure of claim 6, wherein, The length D5 of the connecting printing area in the second direction is 0.05 mm to 1.5 mm.

8. The screen structure of claim 7, wherein, The shortest length D4 of the first connecting printing hole and the second connecting printing hole in the first direction is 20 μm to 200 μm, and / or the width D6 of the first connecting printing hole and the second connecting printing hole in the second direction is 10 μm to 200 μm, and / or the width D7 of the intermediate connecting printing hole in the first direction is 10 μm to 200 μm.

9. The screen structure of claim 5, wherein, The shape of the connecting printing area comprises at least one of H type, N type or inverted 8 type.

10. The screen structure of claim 1, wherein, The second screen does not provide a main grid printing area, and in the second direction, a spacing area is formed between two adjacent sub-grid printing holes, the length of the sub-grid printing hole in the second direction is D2, the width of the spacing area in the second direction is D3, the number of the spacing area is M, the opening rate of the first screen is F, F=D2(M+1) / [D2(M+1)+D3*M], 90%≤F<100%.

11. The screen structure according to any one of claims 1 to 9, wherein The second screen also provides a main grid printing area, and the main grid printing area is configured to form a main grid on the solar cell semi-finished product; The main grid printing area is arranged apart from the connecting printing area in the second direction, and / or the connecting printing area at least partially communicates with the main grid printing area.

12. The screen structure of claim 11, wherein, The number of the main grid printing area is N, and in the second direction, a spacing area is formed between two adjacent sub-grid printing holes, and the number M of the spacing area of each sub-grid printing area is: 1 / 10N≤M≤20N; wherein N is an integer, and N≥1, and M is an integer.

13. The screen structure of claim 11, wherein, The main grid printing area includes a plurality of main grid printing areas, and the plurality of main grid printing areas are arranged apart in the second direction, and when the main grid printing area is arranged apart from the connecting printing area in the second direction, the connecting printing area is located between two adjacent main grid printing areas.

14. The screen structure of claim 11, wherein, When the main grid printing area is arranged apart from the connecting printing area in the second direction, the second screen also provides a main grid overlap printing area, the main grid overlap printing area is at least partially located on the main grid printing area and communicates with the main grid printing area, and the main grid overlap printing area is configured to form a main grid overlap structure at the intersection of the main grid and the sub-grid on the solar cell semi-finished product.

15. The screen structure of claim 14, wherein, The substrate also provides a sub-grid overlap printing area, the sub-grid overlap printing area is at least partially located on the sub-grid printing area and communicates with the sub-grid printing hole, the sub-grid overlap printing area is configured to form a sub-grid overlap structure on the solar cell semi-finished product, and the sub-grid overlap structure is arranged at least partially overlapped with the main grid overlap structure.

16. The screen structure of claim 15, wherein, The main grid overlap structure is wrapped in the sub-grid overlap structure; or, The sub-grid overlap structure is wrapped in the main grid overlap structure.

17. The screen structure according to claim 16, characterized in that, When the main grid overlap structure is wrapped in the sub-grid overlap structure, the maximum width T1 of the main grid overlap printing area in the first direction is 30μm-80μm, the minimum width T2 of the main grid overlap printing area in the first direction is 13μm-80μm, the length T3 of the main grid overlap printing area in the second direction is 0.6mm-1.6mm, the maximum width T4 of the sub-grid overlap printing area in the first direction is 15μm-70μm, the minimum width T5 of the sub-grid overlap printing area in the first direction is 10μm-70μm, and the length T6 of the sub-grid overlap printing area in the second direction is 0.5mm-1.5mm; or, When the sub-grid overlap structure is wrapped around the main-grid overlap structure, the maximum width T1 of the main-grid overlap printed area in the first direction is 15-70 μm, the minimum width T2 of the main-grid overlap printed area in the first direction is 10-70 μm, the length T3 of the main-grid overlap printed area in the second direction is 0.5-1.5 mm, the maximum width T4 of the sub-grid overlap printed area in the first direction is 30-80 μm, the minimum width T5 of the sub-grid overlap printed area in the first direction is 13-80 μm, and the length T6 of the sub-grid overlap printed area in the second direction is 0.6-1.6 mm.

18. A solar cell, characterized by It comprises: a solar cell semi-finished product; an electrode structure comprising a plurality of sub-grids and a connecting structure, the plurality of sub-grids being arranged at intervals in a first direction, each of the sub-grids comprising a plurality of sub-sub-grids arranged at intervals in a second direction to form a break between adjacent two of the sub-sub-grids, and the connecting structure being located at the break and connected to the adjacent two of the sub-sub-grids in the second direction; wherein the first direction and the second direction intersect.

19. The solar cell of claim 18, wherein, The width W1 of the sub-grid in the first direction is 4-30 μm.

20. The solar cell of claim 18, wherein, The height H of the cross section of the sub-grid is 1-10 μm, and / or the smoothness factor of the sub-grid in the height direction is less than or equal to 1.

21. The solar cell of claim 18, wherein, The connecting structure comprises a first connecting line, a second connecting line and an intermediate connecting line, the first connecting line being connected to one of the sub-sub-grids on one side of the break in the second direction, the second connecting line being connected to the other of the sub-sub-grids on the other side of the break in the second direction, and the intermediate connecting line being connected between the first connecting line and the second connecting line.

22. The solar cell of claim 21, wherein, The width of the sub-grid in the first direction is W1, and the shortest length of the first connecting line and the second connecting line in the first direction is W2, W2≥W1.

23. The solar cell of claim 22, wherein, The length W3 of the connecting structure in the second direction is 0.05-1.6 mm.

24. The solar cell of claim 23, wherein, The shortest length W2 of the first connecting line and the second connecting line in the first direction is 40-120 μm, and / or the width W4 of the first connecting line and the second connecting line in the second direction is 2-60 μm, and / or the width W5 of the intermediate connecting line in the first direction is 2-60 μm.

25. The solar cell of claim 21, wherein, The shape of the connecting structure comprises at least one of H type, N type or inverted 8 type.

26. The solar cell according to any one of claims 18 to 25, wherein The electrode structure further comprises a main grid arranged at intervals with the break in the second direction, and / or the break is located on the main grid.

27. The solar cell of claim 26, wherein, The main grid comprises a plurality of main grids arranged at intervals in the second direction, and when the main grid is arranged at intervals with the break in the second direction, the break is located between adjacent two of the main grids.

28. The solar cell of claim 26, wherein the back surface is textured. When the main grid is arranged apart from the fracture in the second direction, the electrode structure further comprises a main grid overlap structure connected to the main grid and located at the intersection of the main grid and the sub-sub grid.

29. The solar cell of claim 28, wherein, The electrode structure further comprises a sub-grid overlap structure connected to the sub-sub grid, and the sub-grid overlap structure is arranged at least partially overlapped with the main grid overlap structure.

30. The solar cell of claim 29, wherein, The main grid overlap structure is wrapped in the sub-grid overlap structure; or The sub-grid overlap structure is wrapped in the main grid overlap structure.

31. The solar cell according to claim 30, wherein, When the main grid overlap structure is wrapped in the sub-grid overlap structure, the maximum width L1 of the main grid overlap structure in the first direction is 35 μm to 90 μm, the minimum width L2 of the main grid overlap structure in the first direction is 20 μm to 90 μm, the length L3 of the main grid overlap structure in the second direction is 0.65 mm to 1.7 mm, the maximum width L4 of the sub-grid overlap structure in the first direction is 20 μm to 75 μm, the minimum width L5 of the sub-grid overlap structure in the first direction is 15 μm to 75 μm, and the length L6 of the sub-grid overlap structure in the second direction is 0.55 mm to 1.6 mm. When the main grid overlap structure is wrapped in the sub-grid overlap structure, the maximum width L1 of the main grid overlap structure in the first direction is 20 μm to 75 μm, the minimum width L2 of the main grid overlap structure in the first direction is 15 μm to 75 μm, the length L3 of the main grid overlap structure in the second direction is 0.55 mm to 1.6 mm, the maximum width L4 of the sub-grid overlap structure in the first direction is 35 μm to 90 μm, the minimum width L5 of the sub-grid overlap structure in the first direction is 20 μm to 90 μm, and the length L6 of the sub-grid overlap structure in the second direction is 0.65 mm to 1.7 mm. The electrode structure further comprises a solder pad and a fishhook, the solder pad comprises a first solder pad and a second solder pad, both ends of the main grid are provided with the first solder pad, the second solder pad is arranged on the main grid between the two first solder pads, and the fishhook is arranged at both ends of the main grid and connected to the first solder pad.

32. The solar cell according to any one of claims 26 to 31, characterized in that The area of the first solder pad is larger than the area of the second solder pad. The solar cell according to any one of claims 18 to 32.

33. A photovoltaic module, characterized by, The method comprises:

34. A method of printing a solar cell using the screen structure according to any one of claims 1 to 17, characterized by, printing a sub-grid with a fracture on a solar cell semi-finished product using a first screen plate; printing a plurality of connection structures on the solar cell semi-finished product using a second screen plate, so that the connection structures are connected between the sub-grids on both sides of the fracture. ​

Images