Screen printing plate, solar cell and photovoltaic module

Abstract

The utility model relates to the technical field of slurry patterning, aims to solve the problem that the service life of a printing screen is affected due to the fact that a bottom layer of a known printing screen is easy to wear, and provides a printing screen, a solar cell and a photovoltaic module. The printing screen comprises a bottom plate layer, a gauze layer and a top plate layer, and the gauze layer is arranged between the bottom plate layer and the top plate layer. The bottom plate layer is a metal plate, and a bottom plate opening is formed in the bottom plate layer. The top plate layer is provided with a top plate opening. The bottom plate opening and the top plate opening correspond in position and are communicated. The gauze layer covers the area where the bottom plate opening and the top plate opening are located. The screen printing plate has the beneficial effects that the screen printing plate is not prone to being scratched and abraded in the printing process, and the service life of the screen printing plate is long. The three-layer overlapped screen printing plate is high in rigidity, not prone to abrasion and beneficial to ensuring that printing boundaries are flat.

Description

Technical Field

[0001] The present application relates to the field of slurry patterning technology, and in particular to a printing screen, a solar cell and a photovoltaic module. Background Art

[0002] The slurry patterning technology can print the slurry on the surface of the target part (such as a battery panel) through a screen with pattern openings to form a pattern composed of slurry materials on the surface of the target part. The slurry patterning technology has been applied to the back patterning of IBC (Interdigitated Back Contact) batteries or other application scenarios.

[0003] However, the known printing screen, whose bottom layer (the layer close to the target part) is made of emulsion film or PI (Polyimide) film, is easily punctured or worn by debris on the surface of the target part (such as solar silicon wafer) or dry slurry in the slurry, reducing the service life of the printing screen. Utility Model Content

[0004] The present application provides a printing screen, an application of the printing screen, a solar cell and a photovoltaic module to solve the problem that the bottom layer of the known printing screen is easily worn, which affects the service life of the printing screen.

[0005] In a first aspect, the present application provides a printing screen, comprising a bottom plate layer, a mesh layer and a top plate layer, wherein the mesh layer is arranged between the bottom plate layer and the top plate layer. The bottom plate layer is a metal plate, and the bottom plate layer is provided with a bottom plate opening. The top plate layer is provided with a top plate opening; the bottom plate opening corresponds to the top plate opening along the stacking direction of the bottom plate layer and the top plate layer and is interconnected. The mesh layer covers the area where the bottom plate opening and the top plate opening are located.

[0006] In the printing screen of the present application, the bottom plate layer is made of a metal plate, which has a high hardness and is not easily scratched or worn during printing, and the service life of the printing screen is relatively long. In addition, the printing screen obtained by superimposing the bottom plate layer, the mesh layer and the top plate layer has high rigidity, is not easily worn, and is conducive to ensuring a smooth printing boundary.

[0007] In a possible embodiment, the mesh layer includes a metal mesh and an electroplating layer, and the electroplating layer is plated on the outer surface of the metal mesh; the mesh layer has tensioning nodes, and the tensioning nodes of the mesh layer are located in the same horizontal plane. In the stacking direction of the bottom plate layer and the top plate layer, the thickness of the electroplating layer is greater than the height of the tensioning nodes of the mesh layer.

[0008] In this embodiment, the thickness of the electroplating layer is greater than the height of the stretching nodes, so that the stretching nodes are covered and the electroplating weakens the stretching nodes, which is beneficial to improving the quality of the printed pattern.

[0009] In a possible implementation, a recessed area is provided on the surface of the top plate layer away from the bottom plate layer.

[0010] In this embodiment, during printing, the scraper squeezes the barrier slurry, and the bubbles in the barrier slurry are squeezed and burst in the recessed area, which promotes the uniform spreading of the barrier slurry and facilitates the formation of a high-quality printed pattern. The greater the pressure of the scraper on the screen, the easier it is to eliminate the bubbles.

[0011] In a possible implementation, the recessed area includes a plurality of pits distributed at intervals, the depth of the pits is 1 to 5 micrometers, and / or the shape of the pits is circular, square, or polygonal with rounded corners.

[0012] In this embodiment, when printing, the scraper squeezes the barrier slurry, and the bubbles in the barrier slurry are squeezed and broken at the pits. Therefore, the surface of the top plate layer is set to a rough morphology with pits, which helps the scraper to squeeze the barrier slurry to break larger bubbles, promote the uniform spreading of the barrier slurry and facilitate the formation of high-quality printing patterns. The greater the pressure of the scraper on the screen, the easier it is to eliminate bubbles.

[0013] In a possible implementation, a functional layer is provided on a surface of the bottom plate layer away from the top plate layer, and the functional layer is a hydrophobic and oleophobic layer.

[0014] In this embodiment, the bottom plate layer has a hydrophobic and oleophobic functional layer on the side away from the top plate layer, which can reduce or avoid the spread of slurry and withstand a certain degree of debris and dry slurry friction, further extending the life of the printing screen and solving the yield problem related thereto. Therefore, the functional layer hinders the spreading of the slurry, and for the functional area requiring a certain thickness and a certain area, this functional layer can be retained or not retained.

[0015] In a possible implementation, the functional layer is a metal film layer, a silicon nitride layer, a fluoride film layer, a polytetrafluoroethylene film layer or an organic silicon film layer.

[0016] In this embodiment, possible constituent materials of the functional layer are given.

[0017] In a possible implementation, the printing screen is used to print the insulating paste.

[0018] In this embodiment, when printing the insulating paste, the bubbles in the paste can be squeezed out through the side walls of the pits, and the expansion of the insulating paste can be limited by the functional layer, thereby ensuring the quality of the printed pattern.

[0019] In a possible implementation, the bottom plate layer is made of a steel plate, the top plate layer is made of a steel plate, and the mesh layer is made of a steel wire mesh.

[0020] In this embodiment, the bottom plate layer and the top plate layer are made of steel plates, and the mesh layer is made of steel wire mesh, which further improves the overall rigidity of the printing screen and helps to improve the quality of the printed pattern.

[0021] In a possible embodiment, the bottom plate opening includes a first direction pattern bottom plate opening and a second direction pattern bottom plate opening; the top plate opening includes a first direction pattern top plate opening and a second direction pattern top plate opening, the first direction pattern bottom plate opening and the first direction pattern top plate opening are correspondingly connected, and the second direction pattern bottom plate opening and the second direction pattern top plate opening are correspondingly connected; the first direction is different from the second direction. The mesh layer includes a first direction pattern portion and a second direction pattern portion, the first direction pattern portion covers the area where the first direction pattern bottom plate opening and the first direction pattern top plate opening are located, and the second direction pattern portion covers the area where the second direction pattern bottom plate opening and the second direction pattern top plate opening are located.

[0022] In this embodiment, the connected first direction pattern bottom plate openings and the second direction pattern bottom plate openings can cross to form a mesh-like bottom plate openings, and the connected first direction pattern top plate openings and the second direction pattern top plate openings can cross to form a mesh-like top plate openings, so that the printing screen can be used to print a mesh pattern.

[0023] In a possible implementation, the printing screen further includes an outer frame. The bottom plate layer, the mesh layer and the top plate layer are connected inside the outer frame. The portion of the second direction pattern portion close to the outer frame includes an edge mesh knot, and the portion of the bottom plate layer and / or the top plate layer close to the outer frame is provided with a concave area toward the inside thereof, and the edge mesh knot is accommodated between the bottom plate layer and the top plate layer.

[0024] In this embodiment, the outer frame can improve the integrity of the printing screen. The edge knot is placed between the bottom plate layer and the top plate layer, which is conducive to hiding the edge knot, thereby ensuring the ink penetration and reducing the screen print.

[0025] In a possible embodiment, the netting mode of the second direction pattern portion is knotless netting, oblique netting or hexagonal netting; and / or, the netting mode of the second direction pattern portion is the same as or different from the netting mode of the first direction pattern portion.

[0026] In this embodiment, a variety of feasible net-stretching forms are provided.

[0027] In a possible embodiment, the first direction pattern bottom plate opening and the first direction pattern top plate opening both extend along the first direction, the second direction pattern bottom plate opening and the second direction pattern top plate opening both extend along the second direction, and the second direction intersects the first direction perpendicularly or obliquely. The width of the first direction pattern bottom plate opening and the first direction pattern top plate opening is greater than or equal to the width of the second direction pattern bottom plate opening and the second direction pattern top plate opening. The first direction pattern bottom plate opening is in a narrowing shape with a reduced width near a portion of the second direction pattern bottom plate opening, and the first direction pattern top plate opening is in a narrowing shape with a reduced width near a portion of the second direction pattern top plate opening; or, the first direction pattern portion is in a narrowing shape with a reduced width near a portion of the second direction pattern portion. Wherein, the width reduction is a gradual reduction or a sudden reduction.

[0028] In this embodiment, by adopting a constriction-shaped design, the degree of slurry overflow can be reduced, and the overflow part compensates the shrinkage area, so that the intersection of the compensated printing pattern forms a figure close to a right angle. Under optimal conditions, when the constriction with a gradually decreasing width is located at the fine grid, the constriction has a greater degree of gradual change toward the slurry printing direction and a smaller degree of gradual change away from the slurry printing direction (i.e., the ink return direction).

[0029] In a second aspect, the present application provides an application of a printing screen, and the printing screen is used for printing non-metallic slurry.

[0030] The printing screen of the present application can be used for printing non-metal slurries, such as insulating slurries, corrosion slurries, etc.

[0031] In a third aspect, the present application provides a solar cell, which includes a pattern printed by the aforementioned printing screen.

[0032] The solar cell of the present application adopts the aforementioned screen printing pattern, and the pattern printing boundary is smooth and the quality is high.

[0033] In a fourth aspect, the present application provides a photovoltaic assembly, which includes the aforementioned solar cell.

[0034] The photovoltaic module of the present application has a solar cell sheet using the aforementioned screen printing pattern, and the pattern printing boundary is smooth and of high quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0036] Figure 1A schematic diagram of the structure of a printing screen according to an embodiment of the present application;

[0037] Figure 2 for Figure 1 A bottom view of the printing screen;

[0038] Figure 3 for Figure 1 A top view of a printing screen;

[0039] Figure 4 It is a schematic diagram of the parallel net form;

[0040] Figure 5 It is a schematic diagram of the oblique net form;

[0041] Figure 6 It is a schematic diagram of the hexagonal network form;

[0042] Figure 7 for Figure 1 A schematic diagram of a first direction pattern portion shrinkage design of a printing screen;

[0043] Figure 8 for Figure 1 A schematic diagram of another implementation of a first direction pattern portion necking design for a printing screen;

[0044] Fig. 9 A schematic diagram of a printed pattern obtained by screen printing with a shrinking design;

[0045] Fig.10 This is a schematic structural diagram of a printing screen according to another embodiment of the present application.

[0046] Description of main component symbols:

[0047] Printing screen 100

[0048] Bottom layer 10

[0049] Functional layer 11

[0050] Mesh layer 20

[0051] First direction pattern portion 21

[0052] Second direction pattern portion 22

[0053] Top layer 30

[0054] Frame 40

[0055] Overflow part 201

[0056] Bottom plate opening K10

[0057] Top plate opening K30

[0058] First direction pattern bottom plate opening K1

[0059] Second direction pattern bottom plate opening K2

[0060] First direction pattern top plate opening K3

[0061] Second direction pattern top plate opening K4

[0062] Hole K5

[0063] First direction Y1

[0064] Second direction Y2 DETAILED DESCRIPTION

[0065] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with 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 of the embodiments.

[0066] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may also be a centered element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may also be a centered element. When an element is considered to be "set on" another element, it may be directly set on the other element or there may also be a centered element. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present application. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The term "or / and" used herein includes any and all combinations of one or more related listed items.

[0068] Some embodiments of the present application are described in detail. In the absence of conflict, the following embodiments and features of the embodiments can be combined with each other.

[0069] Example

[0070] See also Figure 1-Figure 3 The present embodiment provides a printing screen 100 for printing a desired pattern on a solar cell panel, for example, for printing a pattern consistent with a desired solar cell electrode on a solar cell panel. The printing paste may be an insulating paste (or barrier paste). The insulating paste may be used as an insulating barrier.

[0071] In this embodiment, the printing screen 100 includes a bottom plate layer 10, a mesh layer 20 and a top plate layer 30, and the mesh layer 20 is arranged between the bottom plate layer 10 and the top plate layer 30. The bottom plate layer 10 is provided with a bottom plate opening K10, and the top plate layer 30 is provided with a top plate opening K30, and the positions of the bottom plate opening K10 and the top plate opening K30 correspond to each other along the stacking direction of the bottom plate layer 10 and the top plate layer 30 and are interconnected. The mesh layer 20 covers the area where the bottom plate opening K10 and the top plate opening K30 are located. In this way, when printing, the printing paste (such as insulating paste) can be printed on the surface of the solar cell panel or other target parts after passing through the top plate opening K30, the holes of the mesh layer 20 and the bottom plate opening K10, forming a printing pattern consistent with the shape of the bottom plate opening K10.

[0072] In this embodiment, the bottom plate opening K10 includes a first direction pattern bottom plate opening K1 and a second direction pattern bottom plate opening K2 (see Figure 2 The top plate opening K30 includes a first direction pattern top plate opening K3 and a second direction pattern top plate opening K4 (see Figure 3 The first direction pattern top plate opening K3 is connected to the first direction pattern bottom plate opening K1, and the second direction pattern bottom plate opening K2 is connected to the second direction pattern top plate opening K4.

[0073] The mesh layer 20 includes a first directional pattern portion 21 and a second directional pattern portion 22. The first directional pattern portion 21 covers the first directional pattern bottom plate opening K1 and the first directional pattern top plate opening K3. The second directional pattern portion 22 covers the second directional pattern bottom plate opening K2 and the second directional pattern top plate opening K4.

[0074] The first direction pattern bottom plate opening K1, the first direction pattern top plate opening K3 and the first direction pattern portion 21 extend along the first direction Y1 respectively, and the second direction pattern bottom plate opening K2, the first direction pattern top plate opening K3 and the second direction pattern portion 22 extend along the second direction Y2 respectively.

[0075] In this embodiment, the bottom plate layer 10 is a metal plate, such as a steel plate, and its thickness can be determined according to the thickness of the pattern to be printed. The bottom plate layer 10 is a metal plate, which has high hardness and is not easily scratched and worn during printing, and the service life of the printing screen 100 is relatively long.

[0076] The bottom layer of the silk screen in some known technologies is an emulsion film or a PI film, which is easily scratched, punctured or worn by the surface debris of the silicon wafer of the solar panel to be printed or the dry slurry in the barrier slurry during the printing process, thereby reducing the life of the silk screen.

[0077] In this embodiment, the printing screen 100 further includes an outer frame 40, and the bottom plate layer 10, the mesh layer 20 and the top plate layer 30 are connected in the outer frame 40. The outer frame 40 can improve the integrity of the bottom plate layer 10, the mesh layer 20 and the top plate layer 30 and improve the overall structural strength.

[0078] In this embodiment, optionally, the mesh layer 20 and the top plate layer 30 are also made of metal materials, for example, the top plate layer 30 is also made of steel, and the mesh layer 20 is made of steel wire mesh. The top plate layer 30, the bottom plate layer 10 and the mesh layer 20 can be bonded by glue.

[0079] In other embodiments, the top plate layer 30, the bottom plate layer 10 and the mesh layer 20 may also be fixed together by stamping or other forms.

[0080] The printing screen 100 in the form of a steel mesh is obtained by stacking a bottom plate layer 10 and a top plate layer 30 made of metal such as steel, and a steel mesh layer 20. It has high rigidity, is not easy to wear, and is conducive to ensuring a smooth printing edge.

[0081] In contrast, some known screen structures are limited by their own strength, and the tension becomes poor after multiple printings or frequent disassembly and assembly, resulting in PT (point) distortion of the pattern. Cleaning of the barrier slurry will also accelerate the aging of the screen and increase the cost of using the screen.

[0082] In this embodiment, optionally, the mesh layer 20 includes a metal mesh and an electroplating layer, and the electroplating layer is plated on the outer surface of the metal mesh. The mesh layer 20 has a meshing node, and the meshing nodes of the mesh layer 20 are located in the same horizontal plane. In the stacking direction of the bottom plate layer 10 and the top plate layer 30, the thickness of the electroplating layer is greater than the height of the meshing nodes of the mesh layer. The meshing nodes of the mesh layer 20 are located in the same horizontal plane, and the electroplating thickness of the mesh layer 20 is greater than the height of the meshing nodes, so that the meshing nodes are covered, and the electroplating layer weakens the meshing nodes. The use of metal mesh (such as steel mesh) combined with electroplating technology can also improve the yield strength of the printing screen 100, so that the PT stability of the printed pattern is better.

[0083] In some embodiments, the mesh layer 20 is electroplated as a whole with the bottom plate layer 10 and the top plate layer 30, which has the effect of no corrugation mesh knot, and there is no need to consider the damage of the cleaning agent to the printing screen 100, and the PT stability is improved. The mesh layer 20 does not need to be pressed and the outer part of the intersection with the support surface is electroplated, and the mesh knot area is flat and can avoid damage from the cleaning agent.

[0084] In this embodiment, the mesh layer 20 can be an integral mesh and cover the entire surface of the bottom plate layer 10 and the top plate layer 30. The area of ​​the mesh layer 20 corresponding to the first direction pattern bottom plate opening K1 / the first direction pattern top plate opening K3 is designed as the first direction pattern part 21 according to the needs of the main grid. The area of ​​the mesh layer 20 corresponding to the second direction pattern bottom plate opening K2 / the second direction pattern top plate opening K4 is designed as the second direction pattern part 22 according to the needs of the secondary grid. The other parts of the mesh layer 20 are fixed between the top plate layer 30 and the bottom plate layer 10.

[0085] The mesh layer 20 may also only include the first direction pattern portion 21 and the second direction pattern portion 22, the first direction pattern portion 21 is fixed at a position corresponding to the first direction pattern bottom plate opening K1 and the first direction pattern top plate opening K3, and the second direction pattern portion 22 is fixed at a position corresponding to the second direction pattern bottom plate opening K2 and the second direction pattern top plate opening K4. In this embodiment, the portion of the second direction pattern portion 22 close to the outer frame 40 includes an edge mesh knot, and the portions of the bottom plate layer 10 and the top plate layer 30 close to the outer frame 40 are provided with a recessed area toward the inside thereof, and the edge mesh knot is sandwiched between the bottom plate layer 10 and the top plate layer 30, and the edge mesh knot of the second direction pattern portion 22 will be hidden in the top plate layer 30 and the bottom plate layer 10. The edge mesh knot of the second direction pattern portion 22 is hidden in the edge of the top plate layer 30 and the bottom plate layer 10 through the designed size and camera positioning, so that both the ink penetration amount and the absence of obvious reticulated printing are guaranteed. In order to accommodate the edge knots of the second direction pattern portion 22, the outer edge portion of the second direction pattern bottom plate opening K2 of the bottom plate layer 10 or the outer edge portion of the second direction pattern top plate opening K4 of the top plate layer 30 may be recessed by a certain distance to form a certain height difference for accommodating the edge knots of the second direction pattern portion 22. The edge knots of the second direction pattern portion 22 refer to the knots of the second direction pattern portion 22 sandwiched between the top plate layer 30 and the bottom plate layer 10 at the outer edges of the second direction pattern bottom plate opening K2 / the second direction pattern top plate opening K4.

[0086] In this embodiment, the first direction pattern portion 21 and the second direction pattern portion 22 can both be a knotless net (parallel openings, see Figure 4 ), oblique net (such as 22.5° net, 45° net, see Figure 5 ), hexagonal net (i.e. honeycomb net, see Figure 6 ), or other netting methods, which are not limited here. The netting method of the second direction pattern portion 22 and the netting method of the first direction pattern portion 21 can be the same or different. The netting form at the intersection of the first direction pattern portion 21 and the second direction pattern portion 22 can be the same as the first direction pattern portion 21, or the same as the second direction pattern portion 22, or a combination of the first direction pattern portion 21 and the second direction pattern portion 22.

[0087] In one embodiment, the second direction pattern portion 22 adopts a 45° oblique mesh, and the first direction pattern portion 21 adopts a 45° oblique mesh or a honeycomb mesh. This mesh form is relative to the knotless mesh form of the second direction pattern portion 22, which can avoid the collapse of the slurry after solidification at the same position. The intersection of the first direction pattern portion 21 and the second direction pattern portion 22 is replenished with slurry in four directions, which can avoid through holes after cleaning and improve the shaping quality.

[0088] In some known technologies, the slurry used for printing is a barrier slurry, which includes resin, thickener, oxide (filler) and various organic solvents. The barrier slurry may introduce bubbles during the production and storage process. Once these bubbles are squeezed out with the barrier slurry, they will cause the pattern to form a honeycomb structure, affecting the quality of the obtained printed pattern, and even causing the printed pattern to fail.

[0089] See also Figure 3 In this embodiment, a concave area is provided on the surface of the top plate layer 30 away from the bottom plate layer 10, and the concave area can be a plurality of pits K5 distributed at intervals. Figure 3 As shown in FIG. 1 , the pits K5 are arranged in a dot matrix. In this way, when printing, the scraper squeezes the blocking slurry, and the bubbles in the blocking slurry are squeezed and broken at the pits K5. Therefore, the surface of the top plate layer 30 is set to a rough morphology with pits K5, which helps the scraper to squeeze the blocking slurry and break larger bubbles, promotes the uniform spreading of the blocking slurry and is conducive to forming a high-quality printing pattern. The greater the pressure of the scraper on the screen, the easier it is to eliminate bubbles.

[0090] The shape and size of the pit K5 in this embodiment can be set as needed, for example, the depth of the pit K5 is 1 to 5 microns, for example, about 3 microns. The shape of the pit K5 can be circular, square, polygonal with rounded corners (such as honeycomb) or other shapes.

[0091] The top plate layer 30 in this embodiment may be made of a metal plate (such as a steel plate), and the process for forming the pits K5 distributed in a dot matrix on its surface may be laser processing or other processes.

[0092] The printed pattern in this embodiment can be designed as needed. For example, in some embodiments, the printed pattern is in a cross-net shape. To form the printed pattern, in this embodiment, the first direction pattern bottom plate opening K1 and the first direction pattern top plate opening K3 are both along the first direction Y1 ( Figure 2 or Figure 3 The second direction pattern bottom plate opening K2 and the second direction pattern top plate opening K4 are both along the second direction Y2 ( Figure 2 or Figure 3The second direction Y2 is perpendicular to the first direction Y1. In other embodiments, the first direction Y1 and the second direction Y2 can also be set to intersect obliquely as needed. There are multiple first direction pattern bottom plate openings K1 and multiple second direction pattern bottom plate openings K2, respectively, and multiple first direction pattern bottom plate openings K1 and multiple second direction pattern bottom plate openings K2 cross to form a mesh. There are multiple first direction pattern top plate openings K3 and multiple second direction pattern top plate openings K4, respectively, and multiple first direction pattern top plate openings K3 and multiple second direction pattern top plate openings K4 cross to form a mesh.

[0093] In this way, the slurry added on one side of the top plate layer 30 can pass through the first direction pattern top plate opening K3 and the second direction pattern top plate opening K4, the first direction pattern portion 21 and the second direction pattern portion 22 of the mesh layer 20, and the first direction pattern bottom plate opening K1 and the second direction pattern bottom plate opening K2, and adhere to the surface of the target solar substrate (such as a silicon wafer) to form a printed pattern.

[0094] See also Figure 7 or Figure 8 In this embodiment, the width of the first direction pattern bottom plate opening K1 and the first direction pattern top plate opening K3 are greater than the width of the second direction pattern bottom plate opening K2 and the second direction pattern top plate opening K4. The first direction pattern bottom plate opening K1 is in a narrowing shape with a gradually decreasing width near the second direction pattern bottom plate opening K2, and the first direction pattern top plate opening K3 is in a narrowing shape with a gradually decreasing width near the second direction pattern top plate opening K4.

[0095] Optionally, when the gradually changing necking is located at the second direction pattern bottom plate opening K2 and the second direction pattern top plate opening K4, the necking has a greater gradual change toward the slurry printing direction and a smaller gradual change away from the slurry printing direction (i.e., the ink return direction). In other embodiments, the width reduction may also be a sudden reduction, so that the area is in a step-like shape with a gradually decreasing width.

[0096] In other embodiments, due to different slurry properties or functions to be implemented, it can also be set as follows: the second direction pattern bottom plate opening K2 is in a narrowing shape with a reduced width near the first direction pattern bottom plate opening K1, and the second direction pattern top plate opening K4 is in a narrowing shape with a reduced width near the first direction pattern top plate opening K3, while the first direction pattern bottom plate opening K1 and the first direction pattern top plate opening K3 can also be designed with narrowing, or can still maintain a straight shape.

[0097] Figure 7 In the embodiment, the first direction pattern part 21 adopts a hexagonal mesh, and the second direction pattern part 22 adopts a parallel mesh; Figure 8 In the embodiment, the first direction pattern portion 21 adopts a hexagonal mesh, and the second direction pattern portion 22 adopts an oblique mesh.

[0098] In this embodiment, the first direction pattern opening (such as the first direction pattern bottom plate opening K1 and the first direction pattern top plate opening K3) and / or the second direction pattern opening (such as the second direction pattern bottom plate opening K2 and the second direction pattern top plate opening K4) are designed with a shrinkage design, which can effectively reduce the overflow of the blocking slurry at the intersection of the pattern and improve the alignment window of the subsequent patterning process. In this embodiment, the second direction pattern bottom plate opening K2 and the second direction pattern top plate opening K4 are not designed with a shrinkage design and still maintain a straight shape.

[0099] In some embodiments, during the printing process, due to inertia and the low viscosity of the slurry itself, the slurry will diffuse along the printing direction after leaving the printing screen 100, so the first direction pattern portion 21 itself has a certain amount of slurry overflow. Since the second direction pattern portion 22 itself continues to drop ink, its diffusion area needs to be superimposed with the influence of the diffusion on both sides of the second direction pattern portion 22, which is much larger than the diffusion area of ​​the single first direction pattern portion 21. In this embodiment, the first direction pattern bottom plate opening K1 and the first direction pattern top plate opening K3 and / or the second direction pattern bottom plate opening K2 and the second direction pattern top plate opening K4 at the intersection are in a shrinking shape, which can reduce the degree of slurry overflow. The overflow portion 201 compensates for the shrinking area, so that the intersection of the compensated printed pattern 200 forms a figure close to a right angle (see Fig. 9 ).

[0100] See also Fig.10 In another embodiment, the bottom plate layer 10 has a functional layer 11 on the surface away from the top plate layer 30. The functional layer 11 is a hydrophobic and oleophobic layer, such as an inorganic film layer such as a metal film layer, a silicon nitride layer, or a fluoride film layer, or an organic film layer such as a polytetrafluoroethylene film layer or an organic silicon film layer. The functional layer 11 can be formed by plating or coating.

[0101] When the printing screen 100 is used to print insulating slurry (or barrier slurry), the surface of the bottom plate layer 10 away from the top plate layer 30 has a hydrophobic and oleophobic functional layer 11, which can reduce or avoid the spread of slurry and can withstand a certain degree of debris and dry slurry friction. The life of the printing screen 100 is further extended and the yield problems related thereto are solved.

[0102] Of course, in some cases, such as when printing an area that requires a certain thickness, this functional layer can be eliminated to increase the overflow of the slurry after extrusion.

[0103] The method for making the printing screen 100 in this embodiment includes the following steps:

[0104] (1) The bottom plate layer 10 is manufactured.

[0105] A metal plate (such as a steel plate) of a certain thickness is provided, and a first direction pattern bottom plate opening K1 and a second direction pattern bottom plate opening K2 are opened on the metal plate to form a bottom plate opening K10.

[0106] The bottom plate opening K10 may be made by coating a shielding material on a non-opening area of ​​the metal plate and forming the bottom plate opening K10 by etching or laser processing.

[0107] For the implementation with the functional layer 11 , the bottom surface of the obtained bottom plate layer 10 may be plated or coated to obtain the desired hydrophobic and oleophobic functional layer 11 .

[0108] (2) Produce the top plate layer 30.

[0109] A metal plate (such as a steel plate) of a certain thickness is provided, and a first direction pattern top plate opening K3 and a second direction pattern top plate opening K4 are opened on the metal plate to form a top plate opening K30.

[0110] The top surface of the metal plate is processed by etching, laser or other methods to form a surface with distributed pits K5.

[0111] (3) Making the mesh layer 20.

[0112] The cross-pattern grid of the first direction pattern portion 21 and the second direction pattern portion 22 is manufactured according to the bottom plate opening K10 and the top plate opening K30 . The cross-pattern grid can be woven with steel wire and then electroplated.

[0113] (4) Three layers in one.

[0114] The bottom plate layer 10, the mesh layer 20 and the top plate layer 30 are combined into a printing screen 100 by a high-precision visual positioning system, for example, the three layers are tightly combined by a glue material. In the combined three-layer structure, the edge mesh knot of the second direction pattern part 22 is hidden in the bottom plate layer 10 and the top plate layer 30. The three-in-one plate is electroplated, and there is no relative height difference at the intersection of the mesh layer 20 after electroplating, that is, the opening area forms a steel mesh screen integrated with the non-opening support area.

[0115] (5) Detection.

[0116] Detect the PT, tension and other parameters of the printing screen 100.

[0117] According to the test, when the printing screen 100 of this embodiment is used to print insulating paste (or barrier paste), after 20 printings, the printed pattern PT only changes by 0.30, and does not affect the subsequent graphic process window. That is, the life of the printing screen 100 can reach 10 times that of the screen with the same pattern.

[0118] When the insulating paste (or barrier paste) is printed by the printing screen 100 of the present embodiment, the paste is difficult to gather on the surface of the printing screen 100 due to the hydrophobic and oleophobic functional layer 11 of the printing screen 100, and demolding is easier. Figure 7 or Figure 8 After the shrinkage design shown, the insulating paste expands outward to achieve a shaping compensation effect, forming a relatively neat edge morphology.

[0119] The printing screen 100 of this embodiment can also be used for printing other non-metallic pastes (such as etching paste) besides insulating paste.

[0120] For example, the etching slurry printed by the printing screen 100 of the present embodiment can be used for mask opening, passivation film opening or other graphic processes. The printing screen 100 of the present embodiment is suitable for situations where strict requirements are placed on the graphic boundaries and the slurry itself has high viscosity and poor thixotropy. For example, in the preparation process of a back-contact solar cell, a conductive type of doping layer is first formed in an area of ​​the silicon substrate, and then the printing screen 100 of the present embodiment is used to print the etching slurry of the corresponding image. The printed etching slurry corrodes the material in the corresponding area of ​​the doping layer, and the corroded area of ​​the doping layer can be formed into a doping layer of another doping type by the printing screen 100 of the present embodiment (or other methods), and then electrodes are formed on the two doping layers to obtain the desired back-contact solar cell.

[0121] In another embodiment, the printing screen 100 of this embodiment is used to print insulating paste, front surface protection layer printing, IBC component insulating layer and conductive paste printing.

[0122] In another embodiment, after improving the functional layer 11 on the back of the printing screen 100, it can be applied to main grid / aluminum back field printing of various batteries (including but not limited to PERC, TOPcon, IBC, HJT and other structures).

[0123] In another embodiment, the printing screen 100 of this embodiment can also be used to print doping paste to achieve doping of different regions of the solar cell to form an emitter, where the emitter can emit electrons or holes.

[0124] In another embodiment, the printing screen 100 of this embodiment can also be used to print an isolation film for preventing scratches between battery cells. The isolation film can be UV glue or other glue.

[0125] In another embodiment, a solar cell comprises a substrate and a dielectric layer disposed on the substrate, and an etching paste is printed on the dielectric layer to form an opening in the dielectric layer.

[0126] In another embodiment, the printing paste printed by the printing screen 100 may also be a metal paste, so that a metal electrode consistent with the pattern of the bottom plate opening K10 and the top plate opening K30 can be printed. At this time, the functional layer 11 of the printing screen 100 can be replaced with other suitable materials. Among them, the area corresponding to the second direction pattern bottom plate opening K2 and the second direction pattern top plate opening K4 is used to form a collector electrode (such as a fine grid) of the metal electrode. The area corresponding to the first direction pattern bottom plate opening K1 and the first direction pattern top plate opening K3 is used to form an interconnection. The interconnection can be a bus electrode, a pad provided on the bus electrode, a pad or a thickened section provided on a fine ridge, or a portion on the fine ridge for electrical connection to the interconnection. The printing screen 100 is also suitable for printing an interconnection alone.

[0127] The size of the interconnection part can be greater than or equal to the size of the collector electrode. When the size of the interconnection part is equal to the size of the collector grid line, a non-welding process such as a lamination process can be used to achieve the interconnection of the battery, wherein the lamination process refers to directly attaching the carrier film attached to the interconnection part to the battery surface and pressing it to form an electrical interconnection.

[0128] The embodiment of the present application further provides a solar cell, which includes a pattern composed of printing paste printed by a printing screen 100 .

[0129] In one embodiment, the solar cell comprises a cell body and an isolation film, the isolation film is arranged on any surface of the cell body, and the pattern serves as the isolation film.

[0130] In another embodiment, the solar cell comprises a cell body and an electrode structure, the electrode structure comprises an interconnection portion and a collecting electrode, and the pattern serves as the interconnection portion.

[0131] In another embodiment, a solar cell comprises a substrate and a doping layer, wherein the doping layer is formed with an opening, and the opening is obtained by etching a printing paste at a pattern.

[0132] In another embodiment, a solar cell comprises a substrate and a dielectric layer disposed on the substrate, wherein the dielectric layer has an opening, and the opening is obtained by etching a printed paste at a pattern.

[0133] The embodiment of the present application also provides a photovoltaic module, which includes the aforementioned solar cell. The cell includes a cell body and an electrode structure, and the photovoltaic module also includes an insulating layer disposed on the electrode structure, and the insulating layer is printed using the aforementioned printing screen 100.

[0134] The above implementation modes are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the above preferred implementation modes, a person skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A printing screen, characterized in that: It comprises a bottom plate layer, a mesh layer and a top plate layer, wherein the mesh layer is arranged between the bottom plate layer and the top plate layer; The bottom plate layer is a metal plate, and the bottom plate layer is provided with a bottom plate opening; The top plate layer is provided with a top plate opening; the bottom plate opening corresponds to the top plate opening along the stacking direction of the bottom plate layer and the top plate layer and is connected to each other; The mesh layer covers the area where the bottom plate opening and the top plate opening are located.

2. The printing screen according to claim 1, characterized in that: The mesh layer includes a metal mesh and an electroplating layer, wherein the electroplating layer is plated on the outer surface of the metal mesh; the mesh layer has mesh tensioning nodes, and the mesh tensioning nodes of the mesh layer are located in the same horizontal plane. In the stacking direction of the bottom plate layer and the top plate layer, the thickness of the electroplating layer is greater than the height of the mesh tensioning nodes of the mesh layer.

3. The printing screen according to claim 1, characterized in that: A concave area is arranged on the surface of the top plate layer away from the bottom plate layer.

4. The printing screen according to claim 3, characterized in that: The recessed area includes a plurality of pits distributed at intervals; The depth of the pit is 1 to 5 micrometers; and / or the shape of the pit is circular, square or polygonal with rounded corners.

5. The printing screen according to claim 1 or 3, characterized in that: A functional layer is disposed on a surface of the bottom plate layer on one side away from the top plate layer, and the functional layer is a hydrophobic and oleophobic layer.

6. The printing screen according to claim 5, characterized in that: The functional layer is a metal film layer, a silicon nitride layer, a fluoride film layer, a polytetrafluoroethylene film layer or an organic silicon film layer.

7. The printing screen according to claim 1, characterized in that: The bottom plate layer is made of a steel plate, the top plate layer is made of a steel plate, and the mesh layer is made of a steel wire mesh.

8. The printing screen according to claim 1, characterized in that: The bottom plate opening includes a first direction pattern bottom plate opening and a second direction pattern bottom plate opening; the top plate opening includes a first direction pattern top plate opening and a second direction pattern top plate opening, the first direction pattern bottom plate opening and the first direction pattern top plate opening are correspondingly connected, and the second direction pattern bottom plate opening and the second direction pattern top plate opening are correspondingly connected; the first direction is different from the second direction; The mesh layer includes a first directional pattern portion and a second directional pattern portion, the first directional pattern portion covers the area where the first directional pattern bottom plate opening and the first directional pattern top plate opening are located, and the second directional pattern portion covers the area where the second directional pattern bottom plate opening and the second directional pattern top plate opening are located.

9. The printing screen according to claim 8, characterized in that: The printing screen also includes an outer frame; The bottom plate layer, the mesh layer and the top plate layer are connected inside the outer frame; The portion of the second direction pattern portion close to the outer frame includes an edge knot, and the portion of the bottom plate layer and / or the top plate layer close to the outer frame is provided with a recessed area inwardly thereof, and the edge knot is accommodated between the bottom plate layer and the top plate layer.

10. The printing screen according to claim 8, characterized in that: The netting mode of the second directional pattern portion is knotless netting, oblique netting or hexagonal netting; and / or, the netting mode of the second directional pattern portion is the same as or different from the netting mode of the first directional pattern portion.

11. The printing screen according to claim 8, characterized in that: The first direction pattern bottom plate opening and the first direction pattern top plate opening both extend along a first direction, the second direction pattern bottom plate opening and the second direction pattern top plate opening both extend along a second direction, and the second direction intersects the first direction perpendicularly or obliquely; The width of the bottom plate opening of the first directional pattern and the top plate opening of the first directional pattern is greater than or equal to the width of the bottom plate opening of the second directional pattern and the top plate opening of the second directional pattern; A portion of the bottom plate opening of the first directional pattern is in a narrowed shape with a reduced width near the bottom plate opening of the second directional pattern, and a portion of the top plate opening of the first directional pattern is in a narrowed shape with a reduced width near the top plate opening of the second directional pattern; or a portion of the first directional pattern portion is in a narrowed shape with a reduced width near the second directional pattern portion; The width reduction is a gradual reduction or a sudden reduction.

12. A solar cell, characterized in that: The solar cell sheet comprises a pattern printed by the printing screen as claimed in any one of claims 1 to 11.

13. A photovoltaic module, characterized in that: Comprising the solar cell sheet as claimed in claim 12.

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