Solar cell printing screen and solar cell printing method

Abstract

The present invention provides a solar cell printing screen and a printing method, which belongs to the technical field of solar cell preparation, including: setting a support cushion layer with a thickness lower than that of the cell at 1-5mm outside the printing pattern area; the P surface of the screen contacts the cell and the support cushion layer; thickening an emulsion strip of a certain width at 1-5mm outside the printing pattern area on the S surface of the screen; when a scraper scrapes the screen, both ends of the scraper scrape the smeared emulsion strip area and the support cushion layer area. The printing method of solar cells provided by the present invention reduces the height difference between the screen on the support cushion layer and the cell, can alleviate the wear of the cell edge on the screen P surface, protect the P surface of the printing screen, ensure the normal use of the screen, and increase the service life of the screen; at the same time, it avoids defective products caused by screen damage, leakage of slurry and explosion of the screen, and can improve the virtual printing of the edge of the printed pattern and the connection between the main and fine grids, thereby improving the printing effect of the cell.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cell preparation, and in particular relates to a solar cell printing screen and a solar cell printing method. Background Art

[0002] Solar cell screen printing is a printing method that uses a scraper to squeeze the screen cloth and then elastically deform it, and then prints the slurry on the coated silicon wafer. At the beginning of printing, the printing head drives the scraper down to squeeze the screen cloth. The S side of the screen cloth is pressed by the scraper and sticks to the surface of the cell to complete the printing. The scraper's reciprocating motion at the edges of the screen cloth and the cell will cause the emulsion on the top of the screen cloth to gradually become thinner, causing the screen cloth to wear. In addition, during the printing process, the edges of the cell will wear the P side of the screen cloth. If the screen cloth is printed for a long time, it will leak, crack or burst, which will affect the service life of the screen plate, increase the number of defective products, and ultimately increase production costs. Summary of the invention

[0003] The embodiments of the present invention provide a solar cell printing screen and a solar cell printing method, aiming to solve the problem that the screen is easily worn due to the friction of the reciprocating motion of a scraper, which affects the service life and increases the production cost.

[0004] In a first aspect, in order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: to provide a printing method for solar cell sheets, the method comprising:

[0005] A support cushion layer having a thickness lower than that of the battery cell is provided 1-5 mm around the outside of the printed pattern area;

[0006] The P surface of the screen contacts the battery sheet and the supporting cushion layer;

[0007] An emulsion band of a certain width is thickened on the S surface of the screen at a distance of 1-5 mm from the outside of the printing pattern area;

[0008] As the scraper passes over the screen, both ends of the scraper pass over the thickened emulsion belt area and the support pad area.

[0009] In combination with the first aspect, in a possible implementation, thickening the emulsion belt at 1-5 mm around the screen S surface outside the printing pattern area includes:

[0010] The width of the emulsion band applied is consistent with the width of the support cushion layer, and the positions of the emulsion band applied and the support cushion layer overlap vertically;

[0011] The thickness of the applied emulsion band gradually increases from the printed pattern area toward the periphery.

[0012] In combination with the first aspect, in a possible implementation, the thickness of the applied emulsion band is in the range of 1-5 μm.

[0013] In combination with the first aspect, in a possible implementation, the support cushion layer is formed by stacking multiple layers of tape; wherein the tape can be selectively bonded to a printing table supporting the battery cell, or bonded to a surface of a screen P, to form a quadrilateral frame surrounding the printed pattern area.

[0014] In combination with the first aspect, in a possible implementation manner, the quadrilateral frame is formed by stacking multiple layers of adhesive tape with a width of 10-50 mm.

[0015] In combination with the first aspect, in a possible implementation, the quadrilateral frame includes two first long tape layers and two second long tape layers, the first long tape layers are perpendicular to the battery cell main grid, and the second long tape layers are parallel to the battery cell main grid; wherein both ends of the first long tape layer exceed the outer sides of the second long tape layer, and the second long tape layer is located between the two first long tape layers.

[0016] In combination with the first aspect, in a possible implementation manner, the thickness of the first long tape layer and the second long tape layer is 20 μm-50 μm.

[0017] Compared with the prior art, the printing method for solar cell provided by the present invention has the following beneficial effects: a support cushion layer is arranged on the P surface of the screen and outside the printing pattern area, the height difference between the cell and the support cushion layer is reduced, and the emulsion belt is thickened, which can alleviate the wear of the scraper bar on the S surface of the screen when working, and can alleviate the wear of the edge of the cell on the P surface of the screen, thereby ensuring the normal use of the screen and greatly improving the service life of the screen; at the same time, it avoids defective products caused by screen damage, leakage of slurry and explosion of the screen, and can improve the virtual printing of the edge of the printed pattern and the connection between the main and fine grids, thereby improving the printing effect of the cell.

[0018] In a second aspect, an embodiment of the present invention further provides a solar cell printing screen, comprising:

[0019] Screen frame;

[0020] A polyester net is fixed in the net frame;

[0021] A steel wire mesh is fixedly arranged in the polyester mesh;

[0022] The support cushion layer is fixedly arranged on the side of the steel mesh contacting the battery cell. The support cushion layer is a quadrilateral frame. The inner frame size of the support cushion layer is larger than the printing pattern area, and its thickness is smaller than the thickness of the battery cell to be printed.

[0023] In combination with the second aspect, in a possible implementation manner, the hardness of the support cushion layer material is lower than the hardness of the wire mesh material.

[0024] In combination with the second aspect, in a possible implementation, the support cushion layer has a width of 10-50 mm.

[0025] The screen provided in this embodiment is used for printing battery cells. It can reduce the wear of the battery cell edge on the screen P surface, thereby increasing the service life of the screen, reducing the downtime for screen damage and replacement, and reducing production costs; it can also reduce defective products caused by screen leakage and screen explosion, and can improve the situation of virtual printing at the edge of the printed pattern and the connection between the main and fine grids, thereby increasing the printing qualification rate of the battery cells, reducing production costs, improving the printing effect of the battery cells, and improving the quality of battery cell printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the structure after the screen is laid according to an embodiment of the present invention;

[0027] Figure 2 It is a schematic diagram of the structure of the scraper and the screen when printing the battery sheet in the prior art;

[0028] Figure 3 A schematic diagram of the structure of a scraper and a screen during screen printing provided by an embodiment of the present invention;

[0029] Description of reference numerals:

[0030] 1. Screen; 2. Support cushion layer; 21. Second long tape layer; 22. First long tape layer; 3. Printing pattern area; 4. Battery cell; 5. Scraper; 6. Steel wire mesh; 7. Printing table. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0032] Please also read Figure 1 and Figure 3 Now, the printing method of the solar cell provided by the present invention is described. The printing method of the solar cell comprises:

[0033] Step 1: a support cushion layer 2 having a thickness lower than that of the battery cell 4 is provided at 1-5 mm around the outside of the printed pattern area 3;

[0034] Step 2: The screen P surface contacts the battery cell 4 and the support pad 2;

[0035] Step 3, thickening an emulsion strip of a certain width on the screen S surface 1-5 mm outside the printing pattern area 3;

[0036] Step 4: When the scraper 5 scrapes across the screen, both ends of the scraper 5 scrape across the coated emulsion band area and the support pad layer 2 area.

[0037] The solar cell printing method provided by the present invention provides a support cushion layer 2 on the screen P surface and outside the printing pattern area 3. The support cushion layer 2 supports the screen, reduces the height difference between the cell 4 and the printing table 7, and reduces the height difference between the screen on the support cushion layer 2 and the cell 4 after the screen is laid on the cell 4. When the scraper 5 scrapes, it can alleviate the wear of the edge of the cell 4 on the screen P surface, protect the P surface of the printing screen, ensure the normal use of the screen, and improve the service life of the screen; at the same time, it avoids defective products caused by screen damage, leakage and explosion, and can improve the virtual printing of the edge of the printing pattern and the connection between the main and fine grids, thereby improving the printing effect of the cell 4. Thickening the emulsion belt on the S surface of the screen can alleviate the wear of the scraper 5 on the S surface of the screen when working, and improve the service life of the screen.

[0038] pass Figure 2 and Figure 3 By comparison, we can see that Figure 2 Under the pressure of the scraper 5, the middle screen forms a large corner at the edge of the battery cell 4, and the edge of the battery cell 4 scratches the screen, causing wear to the screen; Figure 3 In the process, due to the support of the support cushion layer 2 on the screen, the screen is basically horizontal after being laid, and when the scraper 5 scrapes, the screen and the battery cell 4 remain basically horizontal, reducing the wear of the edge of the battery cell 4 on the screen, thereby improving the service life of the screen. The screen printing method of the solar cell 4 provided by the present invention can be used to improve the screen life of the TOPCon solar cell 4 (i.e., Tunnel Oxide Passivated Contact battery), and is also applicable to the use of screens for printing solar cells of other processes.

[0039] For ease of understanding, some of the terms in this article are explained as follows:

[0040] Screen: used to print metal electrodes on the surface of the battery cell 4.

[0041] Scraper 5: used to squeeze and apply silver paste through the screen and print it on the battery cell 4 to make a metal electrode.

[0042] P surface: screen printing surface, that is, the contact surface between the screen and the battery cell 4.

[0043] S surface: the contact surface between the screen and the scraper 5, that is, the side of the screen facing away from the battery cell 4.

[0044] In step three, if Figure 1 As shown, an emulsion strip is applied on the S surface of the screen 1-5 mm away from the printing pattern area 3. In other words, the emulsion is applied to thicken the four sides of the printing pattern area 3 on the S surface of the screen. When the scraper 5 scrapes, the wear of the scraper 5 on the S surface of the screen can be alleviated, the service life of the screen can be increased, the production cost can be reduced, and the printing effect can be improved. Specifically, it includes:

[0045] The width of the applied emulsion belt is consistent with the width of the supporting cushion layer 2, and the positions of the applied emulsion belt and the supporting cushion layer 2 overlap vertically; the thickness of the applied emulsion belt gradually increases from the printing pattern area 3 to the periphery.

[0046] Since the emulsion around the printed pattern area 3 on the S side of the screen is appropriately thickened, the wear resistance of the screen is also increased, which also plays a key role in extending the service life of the screen.

[0047] In some embodiments, the thickness of the applied emulsion band ranges from 1 to 5 μm. The emulsion is thickened by 1 to 5 μm in a gradient pattern around the printed pattern area 3 on the S surface of the screen, and its wear resistance is increased while ensuring the printing effect, so as to alleviate the wear of the screen caused by the reciprocating motion of the scraper 5 on the contact surface between the screen and the scraper 5 during the production process, thereby increasing the wear resistance of the screen and thus improving the service life of the screen.

[0048] In some embodiments, Figure 1 As shown, the support cushion layer 2 is formed by stacking multiple layers of adhesive tape; wherein the adhesive tape is bonded to the printing table 7 supporting the battery cell 4, or to the screen P surface, forming a quadrilateral frame surrounding the printed pattern area 3. The support cushion layer 2 formed by stacking multiple layers of adhesive tape has a certain buffer and elasticity, and the hardness is lower than that of the scraper 5 and the screen, and the scraper 5 will not cause wear to the screen when scraping the screen.

[0049] Optionally, the support cushion layer can be directly fixed on the screen, or fixed on the printing table, or made into an independent quadrilateral frame. When in use, the support cushion layer is placed on the printing table and surrounded by the battery cell. By reducing the height difference between the screen on the battery cell and the support cushion layer during printing, the screen is kept basically horizontal, the wear and tear of the battery cell on the screen is alleviated, and the problem of leakage of slurry affecting the printing pass rate of the battery cell when the wear is serious is avoided.

[0050] During the specific winding, the support cushion layer 2 can be pre-stacked on the screen with tape. The tape can have multiple layers (1 to 5), generally not more than 3 layers. According to the printing effect and the thickness of the battery cell 4, 3 layers of tapes of different thicknesses can be used to achieve the required thickness requirements.

[0051] Optionally, tape can be used at the chamfer position of the cell 4, pasted parallel to the chamfer, and matched with the support pad layer on the periphery of the cell to reduce the wear of the cell edge on the screen. For example, a layer of tape is pasted at the chamfer position of the cell, and three layers of tape are used for the support pad layer.

[0052] In some embodiments, Figure 1 As shown, multiple layers of adhesive tape with a width of 10-50 mm are stacked to form a quadrilateral frame, forming a support cushion layer 2 with a width of 10-50 mm. It is best to make the two ends of the scraper 5 located in the middle of the support cushion layer 2 on one side.

[0053] In some embodiments, Figure 1 As shown, the quadrilateral frame includes two first long tape layers 22 and two second long tape layers 21, the first long tape layer 22 is perpendicular to the main grid of the battery cell 4, and the second long tape layer 21 is parallel to the main grid of the battery cell 4; wherein, both ends of the first long tape layer 22 exceed the outer sides of the second long tape layer 21, and the second long tape layer 21 is located between the two first long tape layers 22.

[0054] As shown in the figure, the four sides around the printed pattern on the screen P surface are the locations for pasting tape. Among them, the two sides perpendicular to the main grid are pasted with a tape with a thickness of 20μm-50μm, and the length is the length of the printed pattern plus twice the width of the tape; the upper and lower positions parallel to the main grid are pasted with a tape with a thickness of 20μm-50μm. Both can adopt a multi-layer pasting mode to achieve the ideal printing effect. The pasted tape layer is equivalent to reducing the height difference between the screen and the battery cell 4. When the scraper 5 scrapes, it can reduce the wear of the edge of the battery cell 4 on the mesh cloth and protect the printed screen P surface. The thickness of the pasted tape can be tested on the production line. While ensuring the printing effect, increasing the thickness of the tape can not only improve the overall printing effect of the battery cell 4, but also increase the service life of the screen.

[0055] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0056] Based on the same inventive concept, the present application also provides a solar cell printing screen, such as Figure 1 and Figure 3As shown, it includes: a screen frame, a polyester screen and a steel mesh 6, the polyester screen is fixed in the screen frame; the steel mesh 6 is fixed in the polyester screen, and the steel mesh 6 is bonded and fixed to the polyester screen; the support cushion layer 2 is fixed on the side of the steel mesh 6 that contacts the battery cell 4, the support cushion layer 2 is a quadrilateral frame, the inner frame size of the support cushion layer 2 is larger than the printing pattern area 3, and its thickness is smaller than the thickness of the battery cell 4 to be printed, and the support cushion layer 2 has a supporting effect on both ends of the scraper 5 to reduce the height difference between the screen and the battery cell 4, thereby reducing the wear of the edge of the battery cell on the screen, avoiding screen damage and leakage, reducing the number of poorly printed sheets, increasing the service life of the screen, and improving the printing effect of the battery cell.

[0057] In some embodiments, the hardness of the material of the support cushion layer 2 is lower than that of the material of the steel mesh 6 to avoid wear on the steel mesh 6. Specifically, the support cushion layer 2 can be made of aluminum foil, PVC (PVC is a plastic material, i.e., polyvinyl chloride), PET (Polyethylene terephthalate, commonly known as polyester resin), PI (abbreviation for polyimide), and the like.

[0058] In some embodiments, the width of the support pad layer 2 is 10-50 mm, which is the width of the first long tape layer 22 and the second long tape layer 21 .

[0059] Specifically, the support cushion layer 2 is formed by stacking multiple layers of adhesive tape to form a quadrilateral frame. The screen is supported by the support cushion layer 2, which reduces the unevenness of the screen after laying, and avoids wear of the screen when the scraper 5 scrapes.

[0060] The screen provided in this embodiment is used for printing the battery cell 4, and can reduce the wear of the edge of the battery cell 4 on the screen P surface, thereby increasing the service life of the screen, reducing the downtime for screen damage and replacement, and reducing production costs; it can also reduce defective products caused by screen leakage and screen explosion, and can improve the situation of virtual printing at the edge of the printed pattern and the connection between the main and fine grids, thereby increasing the printing pass rate of the battery cell 4, reducing production costs, improving the printing effect of the battery cell 4, and improving the printing quality of the battery cell 4.

[0061] The experimental process and experimental results of the method of the present invention are as follows:

[0062] Experimental process design:

[0063] ① Run regular screens without tape and thickened emulsion on the normal production line of printing equipment, and track the batch use effect, including the number of screen printed pieces and the number of unqualified pieces;

[0064] ② The experimental screen of the present invention is put into production on the same printing production line, and the batch usage is tracked, and the number of mass production prints, unqualified output and battery efficiency changes are counted.

[0065] Experimental results:

[0066]

[0067] Since silver paste accounts for a large proportion of the production cost of solar cells, as the grid lines are required to be thinner and thinner, the cost of the screen has also increased. The present invention not only increases the service life of the screen, but also reduces the defective products and paste losses caused by false printing, leakage and explosion of the screen, which can bring great economic benefits.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for printing a solar cell, characterized in that: The method comprises: A support cushion layer (2) having a thickness lower than that of the battery cell (4) is provided at a distance of 1-5 mm from the outside of the printed pattern area (3); The screen P surface contacts the battery sheet (4) and the supporting cushion layer (2); A thickened emulsion strip of a certain width is added on the screen S surface at a position 1-5 mm outside the printing pattern area (3); When the scraper (5) scrapes across the screen (1), both ends of the scraper (5) scrape across the smeared emulsion band area and the support cushion layer (2) area; The thickened emulsion band on the screen S surface at a distance of 1-5 mm from the printing pattern area (3) comprises: The width of the emulsion band applied is consistent with the width of the support cushion layer (2), and the emulsion band applied and the support cushion layer (2) are stacked up and down; The thickness of the applied emulsion band gradually increases from the printed pattern area (3) toward the periphery; The thickness of the applied emulsion band ranges from 1 to 5 μm.

2. The method for printing a solar cell according to claim 1, wherein: The support cushion layer (2) is formed by stacking multiple layers of adhesive tape; wherein the adhesive tape can be selectively bonded to a printing table (7) supporting the battery sheet (4), or bonded to a screen P surface, to form a quadrilateral frame surrounding the printed pattern area (3).

3. The method for printing a solar cell according to claim 2, wherein: The quadrilateral frame is formed by stacking multiple layers of adhesive tape with a width of 10-50 mm.

4. The method for printing a solar cell according to claim 2, wherein: The quadrilateral frame comprises two first long tape layers (22) and two second long tape layers (21), wherein the first long tape layers (22) are perpendicular to the main grid of the battery cell (4), and the second long tape layers (21) are parallel to the main grid of the battery cell (4); wherein both ends of the first long tape layers (22) exceed the outer sides of the second long tape layers (21), and the second long tape layers (21) are located between the two first long tape layers (22); and the scraper (5) moves along the length direction of the first long tape layers (22).

5. The method for printing a solar cell according to claim 4, characterized in that: The thickness of the first long adhesive tape layer (22) and the second long adhesive tape layer (21) is 20 μm-50 μm.

6. A solar cell printing screen, used in the solar cell printing method according to any one of claims 1 to 5, characterized in that: include: Screen frame; A polyester net is fixed in the net frame; A steel wire mesh (6) is fixedly arranged in the polyester mesh; The support cushion layer (2) is fixedly arranged on the side of the steel wire mesh (6) contacting the battery cell (4), the support cushion layer (2) is a quadrilateral frame, the inner frame size of the support cushion layer (2) is larger than the printing pattern area (3), and the thickness thereof is smaller than the thickness of the battery cell (4) to be printed.

7. The solar cell printing screen as claimed in claim 6, characterized in that: The hardness of the material of the supporting cushion layer (2) is lower than the hardness of the material of the steel wire mesh (6).

8. The solar cell printing screen as claimed in claim 6, characterized in that: The width of the supporting cushion layer (2) is 10-50 mm.

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