A special-shaped scraper structure for realizing silk screen secondary printing

Abstract

The present application relates to the technical field of photovoltaic cell manufacturing, and discloses a special-shaped scraper structure for realizing secondary screen printing, comprising: a scraper provided with a scraping strip, two impression areas formed on the working surface of the scraping strip, and the two impression areas arranged in sequence in the movement direction of the scraper; wherein the two impression areas form a first distance in the thickness direction, the two impression areas form a second distance in the height direction, and the ratio of the first distance to the second distance corresponds to the tangent value of the installation angle of the scraper. The present application improves the quality of printed grid lines, so that the scraper contacts the screen plate through the two impression areas and applies pressure in one scraping stroke, thereby realizing multiple effective transfers of paste in a single stroke, significantly increasing the metal load, height and width-height ratio of the printed grid lines, and thus obtaining a more full and larger-conducting-section grid line appearance; the special-shaped scraper structure maintains the advantages of production efficiency and cost, the manufacturing cost is controllable, and the economic efficiency is high.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell manufacturing technology, and more specifically, to a special-shaped scraper structure for realizing secondary screen printing. Background Technology

[0002] In the screen printing process of photovoltaic cell manufacturing, the squeegee's role is to apply pressure and speed to make silver or aluminum paste pass through the mesh of the screen and be precisely printed onto the silicon wafer to form grid electrodes. The state of the squeegee directly affects the height, width, cross-sectional shape, and uniformity of the grid lines, thereby affecting the cell's conductivity, light-blocking loss, and series resistance.

[0003] Currently, in the screen printing process of crystalline silicon solar cells, the morphology of the metal grid lines (especially the height and aspect ratio) is a key factor determining their conductivity, series resistance, and cell conversion efficiency. To obtain better electrical performance, taller and fuller grid lines need to be printed. However, existing technologies still have the following problems: 1. Limited performance of grid lines printed in a single pass. Traditional squeegees have a simple structure with a single hardness and a single working surface. In a single printing stroke, only one paste transfer can be performed, which may result in insufficient height, fullness and cross-sectional shape of the printed grid line electrodes. This affects the conductivity of the grid lines and the contact quality with the silicon wafer, thus limiting the further improvement of cell conversion efficiency. 2. Trade-off between efficiency and performance: In order to improve grid line performance, the industry may need to adopt a multi-printing process, but this will significantly increase the printing time of a single cell, reduce production efficiency, and increase production costs.

[0004] Therefore, it is necessary to propose a non-standard squeegee structure for secondary screen printing, which can improve the height and fullness of the grid lines obtained in a single printing without increasing the printing stroke or reducing production efficiency, so as to solve the problems existing in the prior art. Summary of the Invention

[0005] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] To at least partially solve the above problems, the present invention provides a special-shaped squeegee structure for realizing secondary screen printing, comprising: a squeegee with a squeegee strip, wherein two imprinting areas are formed on the working surface of the squeegee strip, and the two imprinting areas are arranged sequentially in the direction of movement of the squeegee; The two imprinting areas form a first distance in the thickness direction and a second distance in the height direction. The ratio of the first distance to the second distance corresponds to the tangent of the installation angle of the scraper.

[0007] Preferably, the scraper includes a first scraper unit and a second scraper unit, and two imprinting areas are respectively formed at the leading edge of the bottom of the first scraper unit and the second scraper unit; The first scraper unit and the second scraper unit are located on the same side of the scraper. Alternatively, the first scraper unit and the second scraper unit may be respectively located on both sides of the scraper.

[0008] Preferably, the first scraper unit and the second scraper unit are stacked on the front side of the scraper, with the first scraper unit positioned close to the scraper and the second scraper unit positioned away from the scraper, and the bottom of the first scraper unit being lower than the bottom of the second scraper unit.

[0009] Preferably, the scraper has an installation opening at the bottom front side, the first scraper unit is disposed at the installation opening, and the second scraper unit is disposed on the front side of the scraper and above the installation opening.

[0010] Preferably, the first scraper unit is disposed on the rear side of the scraper, the second scraper unit is disposed on the front side of the scraper, the bottom of the first scraper unit is lower than the bottom of the second scraper unit, and the bottom of the scraper forms an inclined surface.

[0011] Preferably, the scraper includes a third scraper unit disposed on the front side of the scraper, and a concave arc surface is formed on the working surface of the third scraper unit, with two imprinting areas formed at the front and rear edges of the concave arc surface, respectively.

[0012] Preferably, the first scraper unit and the second scraper unit are made of elastic materials with different hardness.

[0013] Preferably, the hardness of the first scraper unit is greater than the hardness of the second scraper unit.

[0014] Preferably, the connection between the first scraper unit, the second scraper unit, and the scraper blade is riveted or adhesive.

[0015] Preferably, the installation angle of the scraper is the angle between the scraper and the horizontal plane.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: The irregular squeegee structure for secondary screen printing described in this invention improves the quality of the printed grid lines. It allows the squeegee to contact the screen and apply pressure through two printing zones during a single printing stroke, thereby achieving multiple effective transfers of paste in a single stroke. This significantly increases the metal load, height, and aspect ratio of the printed grid lines, resulting in a fuller grid line morphology with a larger conductive cross-section. The improvement in the grid line morphology directly translates into lower grid line series resistance and higher fill factor, providing a key guarantee for ultimately improving the photoelectric conversion efficiency of the battery. The irregular squeegee structure design also maintains the advantages of production efficiency and cost. All performance improvements are completed within one squeegee stroke, maintaining the original production capacity and overcoming the fatal defect of traditional secondary printing process that leads to a halving of production capacity. At the same time, this design does not increase the consumption of precious metal paste, and the manufacturing cost is controllable, making it highly economical. The irregular squeegee structure of the present invention can be flexibly adapted to various existing screen printing machines, different squeegee installation angles, and diverse paste characteristics by adjusting the material hardness, stacking method, and morphological parameters of the working surface, making it easy to promote and implement on existing production lines.

[0017] The irregular squeegee structure for achieving secondary screen printing described in this invention, along with other advantages, objectives, and features of this invention, will be partly apparent from the following description and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 A schematic diagram of a conventional scraper structure with a single-sided design in the prior art; Figure 2 A schematic diagram of a conventional scraper structure with double-sided design in the prior art; Figure 3 This is a schematic diagram showing the positional structure of the two imprinting zones in the irregular squeegee structure for achieving secondary screen printing as described in this invention. Figure 4 This is a schematic diagram of the first structure of the scraper bar in the irregular squeegee structure for achieving secondary screen printing according to the present invention; Figure 5 This is a schematic diagram of the second structure of the scraper bar in the irregular squeegee structure for achieving secondary screen printing according to the present invention; Figure 6 This is a schematic diagram of the third structure of the scraper bar in the irregular squeegee structure for achieving secondary screen printing as described in this invention. Figure 7This is a schematic diagram of the fourth structure of the scraper bar in the irregular squeegee structure for achieving secondary screen printing as described in this invention; Figure 8 This is a schematic diagram showing the contact between the squeegee bar and the screen in the irregular squeegee structure for achieving secondary screen printing as described in this invention. Figure 9 This is a schematic diagram showing the contact between the squeegee bar and the screen in the irregular squeegee structure for achieving secondary screen printing as described in this invention.

[0019] In the attached diagram: 1 is the scraper, 2 is the printing area, 3 is the first scraper unit, 4 is the second scraper unit, 5 is the third scraper unit, 51 is the concave arc surface, 6 is the screen, and 7 is the scraper body. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, so that those skilled in the art can implement it based on the description.

[0021] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0022] like Figure 1 and Figure 2 As shown, this is a conventional scraper structure. The scraper body 7 is a single-sided or double-sided design. When the scraper body 7 is working, it achieves single printing through one edge at its bottom.

[0023] like Figures 3-9 As shown, the present invention provides a special-shaped squeegee structure for realizing secondary screen printing, including: a squeegee 1, on which a squeegee strip is provided, and two imprinting areas 2 are formed on the working surface of the squeegee strip, and the two imprinting areas 2 are arranged sequentially in the movement direction of the squeegee 1. The two imprinting areas 2 form a first distance in the thickness direction and a second distance in the height direction. The ratio of the first distance to the second distance corresponds to the tangent of the installation angle of the scraper 1.

[0024] The installation angle of the scraper 1 is the angle between the scraper 1 and the horizontal plane.

[0025] The working surface of the squeegee has an irregular shape, forming two printing areas 2 for contacting the screen 6 along the movement direction of the squeegee 1. This allows the squeegee to make two contacts with the screen 6 in a single stroke of the squeegee 1, thus enabling repeated printing.

[0026] To ensure that the two imprinting zones 2 can work in an orderly and continuous manner, the first distance, the second distance, and the installation angle of the scraper 1 must satisfy the following relationship: ,in, The installation angle of scraper 1 The tangent value, The first distance, This is the second distance; The positional relationship between the two imprinting areas 2 is designed based on the installation angle of the squeegee 1, allowing the irregularly shaped squeegee structure to be adapted to any installation angle of the squeegee 1 in the prior art, such as compatible squeegee 1 installation angles of 55°, 60°, 65°, etc. Figure 8 and Figure 9 The diagram shows the installation angle of scraper 1 at 55°.

[0027] Through the above design, the irregular squeegee structure improves the quality of the printed grid lines, so that the squeegee 1 contacts the screen 6 and applies pressure through the two printing zones 2 in one printing stroke, thereby achieving multiple effective transfers of paste in a single stroke, significantly increasing the metal load, height and aspect ratio of the printed grid lines, thus obtaining a fuller grid line morphology with a larger conductive cross section. The improvement in the grid line morphology directly translates into lower grid line series resistance and higher fill factor, providing a key guarantee for ultimately improving the photoelectric conversion efficiency of the battery. The irregularly shaped scraper structure design also maintains the advantages of production efficiency and cost. All performance improvements are completed within a single scraping stroke, maintaining the original production capacity and overcoming the fatal flaw of traditional secondary printing processes that result in a halving of production capacity. At the same time, this design does not increase the consumption of precious metal paste, and the manufacturing cost is controllable, making it highly economical.

[0028] like Figures 3-6 As shown, in one embodiment, the squeegee includes a first squeegee unit 3 and a second squeegee unit 4, and two imprinting areas 2 are respectively formed at the leading edges of the bottom of the first squeegee unit 3 and the second squeegee unit 4; The first scraper unit 3 and the second scraper unit 4 are disposed on the same side of the scraper 1; Alternatively, the first scraper unit 3 and the second scraper unit 4 are respectively disposed on both sides of the scraper 1.

[0029] The bottom of the first scraper unit 3 and the second scraper unit 4 form a stepped working surface. During printing, the stepped working surface contacts the screen 6, and repeated printing is achieved through the two printing areas 2.

[0030] The first scraper unit 3 and the second scraper unit 4 are made of elastic materials with different hardness. Preferably, the hardness of the first scraper unit 3 is greater than the hardness of the second scraper unit 4.

[0031] To ensure that even with minor errors in the installation angle, the printing area 2 on the first scraper unit 3 and the printing area 2 on the second scraper unit 4 can always be in effective contact with the screen 6, thus guaranteeing the printing effect.

[0032] The first scraper unit 3 and the second scraper unit 4 can be selected from any type of elastic material with any hardness in the existing technology. For example, the hardness of commonly used elastic materials is 65A, 70A, and 75A. The hardness unit is A, which represents Shore A hardness. The larger the number, the harder the material.

[0033] The irregular squeegee structure of the present invention can be flexibly adapted to various existing screen printing machines, different squeegee 1 installation angles, and diverse paste characteristics by adjusting the material hardness, stacking method, and working surface morphology parameters, making it easy to promote and implement on existing production lines.

[0034] like Figure 4 As shown, in one embodiment, the first scraper unit 3 and the second scraper unit 4 are stacked on the front side of the scraper 1. The first scraper unit 3 is disposed close to the scraper 1, and the second scraper unit 4 is disposed away from the scraper 1. The bottom of the first scraper unit 3 is lower than the bottom of the second scraper unit 4.

[0035] This embodiment represents the first structure of the scraper. The first scraper unit 3 and the second scraper unit 4 are stacked on the same side of the scraper plate 1. The thickness of the first scraper unit 3 is W1, the thickness of the second scraper unit 4 is W2, and the height is H2. The height difference between the bottom of the first scraper unit 3 and the second scraper unit 4 is H1. Therefore, the first distance between the two imprinting areas 2 in the thickness direction is W2, and the second distance in the height direction is H1. The relationship between the installation angle of the scraper plate 1 and the first and second distances can be expressed as: .

[0036] This embodiment provides a design hardness and size for the scraper blade. The design hardness of the first scraper blade unit 3 is 75A, the design hardness of the second scraper blade unit 4 is 70A, W1=W2=3.8mm, H1=2.66mm, H2=12.85mm, and the scraper angle α=55°.

[0037] like Figure 5 As shown, in one embodiment, the scraper 1 has an installation port at the bottom front side, the first scraper unit 3 is disposed at the installation port, and the second scraper unit 4 is disposed on the front side of the scraper 1 and above the installation port.

[0038] This embodiment represents a second structure for the scraper. The first scraper unit 3 and the second scraper unit 4 are located on the same side of the scraper 1 and are connected to the scraper 1 respectively. The thickness of the first scraper unit 3 is W5 and the height is H5. The thickness of the second scraper unit 4 is W6 and the height is H6. The bottom of the second scraper unit 4 is flush with the top of the first scraper unit 3. Therefore, the first distance between the two imprinting areas 2 in the thickness direction is W6, and the second distance in the height direction is H5. The relationship between the installation angle of the scraper 1 and the first and second distances can be expressed as follows: .

[0039] This embodiment provides a design hardness and size for the scraper blade. The design hardness of the first scraper blade unit 3 is 75A, the design hardness of the second scraper blade unit 4 is 70A, W5=1.6mm, W6=6mm, H5=4.2mm, H6=15.2mm, and the scraper angle α=55°.

[0040] like Figure 6 As shown, in one embodiment, the first scraper unit 3 is disposed on the rear side of the scraper 1, the second scraper unit 4 is disposed on the front side of the scraper 1, the bottom of the first scraper unit 3 is lower than the bottom of the second scraper unit 4, and the bottom of the scraper 1 forms a slope.

[0041] This embodiment represents the third structure of the scraper. The first scraper unit 3 and the second scraper unit 4 are located on both sides of the scraper 1. The thickness of the first scraper unit 3 is W8, and its height is H8. The thickness of the second scraper unit 4 is W7, and its height is H7. The thickness of the scraper 1 is W0. The height difference between the bottom of the first scraper unit 3 and the second scraper unit 4 is H9. Therefore, the first distance between the two imprinting areas 2 in the thickness direction is W7 + W0, and the second distance in the height direction is H9. The relationship between the installation angle of the scraper 1 and the first and second distances can be expressed as follows: .

[0042] This embodiment provides a design hardness and size for the scraper blade. The design hardness of the first scraper blade unit 3 is 75A, the design hardness of the second scraper blade unit 4 is 70A, W8=3.8mm, W0=1.6mm, H7=15.5mm, H8=15.5mm, H9=3.78mm, and the scraper angle α=55°.

[0043] like Figure 7 As shown, in one embodiment, the scraper includes a third scraper unit 5, which is disposed on the front side of the scraper 1. A concave arc surface 51 is formed on the working surface of the third scraper unit 5, and two imprinting areas 2 are respectively formed at the front edge and the rear edge of the concave arc surface 51.

[0044] This embodiment is the fourth structure of the squeegee. The third squeegee unit 5 is located on the front side of the squeegee 1 and is formed by processing a single elastic material block. Its working surface is processed into a concave arc surface 51. During squeegee printing, two printing areas 2 are formed at the front and rear edges of the concave arc surface 51 for contacting the screen 6, thereby achieving repeated printing. The thickness of the third scraper unit 5 is W3, the height of the concave arc surface 51 is H3, and the thickness of the concave arc surface 51 is W4. Therefore, the first distance between the two imprinting areas 2 in the thickness direction is W4, and the second distance in the height direction is H3. The relationship between the installation angle of the scraper 1 and the first and second distances can be expressed as: .

[0045] This embodiment provides a design hardness and size for the scraper. The design hardness of the third scraper unit 5 is 70A, W3=7.6mm, W4=3.8mm, H3=2.66mm, H4=12.85mm, and the scraper angle α=55°.

[0046] The above four structures of scraper blades, such as Figures 4-7 As shown in the figure, the dimensions marked in the figure are one of the available dimensions (in millimeters) calculated when the installation angle of scraper 1 is 55°. Of course, the present invention is not limited to the dimensions marked in the figure, and the first distance and the second distance can be adjusted according to actual needs.

[0047] In one embodiment, the connection between the first scraper unit 3, the second scraper unit 4, and the scraper 1 is riveted or adhesive.

[0048] Preferably, in the second structure of the scraper, the first scraper unit 3, the second scraper unit 4 and the scraper 1 are riveted together; in the third structure of the scraper, the first scraper unit 3, the second scraper unit 4 and the scraper 1 are adhesively connected.

[0049] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the present invention, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A non-circular squeegee structure for achieving secondary screen printing, characterized in that, include: A scraper (1) is provided with a scraper strip, and two imprinting areas (2) are formed on the working surface of the scraper strip. The two imprinting areas (2) are arranged sequentially in the direction of movement of the scraper (1). Among them, the two imprinting areas (2) form a first distance in the thickness direction and a second distance in the height direction. The ratio of the first distance and the second distance corresponds to the tangent of the installation angle of the scraper (1).

2. The irregularly shaped squeegee structure for achieving secondary screen printing according to claim 1, characterized in that, The scraper includes a first scraper unit (3) and a second scraper unit (4), and two imprinting areas (2) are respectively formed at the leading edge of the bottom of the first scraper unit (3) and the second scraper unit (4); The first scraper unit (3) and the second scraper unit (4) are located on the same side of the scraper (1); Alternatively, the first scraper unit (3) and the second scraper unit (4) are respectively arranged on both sides of the scraper (1).

3. The irregularly shaped squeegee structure for achieving secondary screen printing according to claim 2, characterized in that, The first scraper unit (3) and the second scraper unit (4) are stacked on the front side of the scraper (1). The first scraper unit (3) is located close to the scraper (1), and the second scraper unit (4) is located away from the scraper (1). The bottom of the first scraper unit (3) is lower than the bottom of the second scraper unit (4).

4. The irregularly shaped squeegee structure for achieving secondary screen printing according to claim 2, characterized in that, The scraper (1) has an installation port at the bottom front side, the first scraper unit (3) is located at the installation port, and the second scraper unit (4) is located on the front side of the scraper (1) and above the installation port.

5. The irregularly shaped squeegee structure for achieving secondary screen printing according to claim 2, characterized in that, The first scraper unit (3) is located on the rear side of the scraper (1), and the second scraper unit (4) is located on the front side of the scraper (1). The bottom of the first scraper unit (3) is lower than the bottom of the second scraper unit (4), and the bottom of the scraper (1) forms an inclined surface.

6. The irregularly shaped squeegee structure for achieving secondary screen printing according to claim 1, characterized in that, The scraper includes a third scraper unit (5), which is disposed on the front side of the scraper (1). A concave arc surface (51) is formed on the working surface of the third scraper unit (5), and two imprinting areas (2) are formed at the front and rear edges of the concave arc surface (51), respectively.

7. The irregularly shaped squeegee structure for achieving secondary screen printing according to claim 2, characterized in that, The first scraper unit (3) and the second scraper unit (4) are made of elastic materials with different hardness.

8. The irregularly shaped squeegee structure for achieving secondary screen printing according to claim 7, characterized in that, The hardness of the first scraper unit (3) is greater than that of the second scraper unit (4).

9. The irregularly shaped squeegee structure for achieving secondary screen printing according to claim 2, characterized in that, The connection between the first scraper unit (3), the second scraper unit (4) and the scraper (1) is riveted or glued.

10. The irregularly shaped squeegee structure for achieving secondary screen printing according to claim 1, characterized in that, The installation angle of the scraper (1) is the angle between the scraper (1) and the horizontal plane.

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