Soft contact printing method of photovoltaic cell grid line paste and soft contact printing mold

Abstract

This invention relates to the field of photovoltaic technology, and discloses a soft-contact printing method and a soft-contact printing mold for photovoltaic cell grid line paste. The soft-contact printing method includes: placing a silicon wafer under a mold; a driving component moving a printing head downwards until a gap is formed between the printing head and the silicon wafer surface, then stopping the downward movement of the printing head; a magnetic field generator driving a propeller via magnetic force to push the grid line paste in the paste filling cavity downwards and overflow from the bottom surface of the opening area; the printing head moving upwards, ensuring that the distance between the bottom surface of the opening area and the silicon wafer surface is less than the distance the propeller pushes the grid line paste downwards, so that the overflowing grid line paste detaches from the mold and contacts the silicon wafer surface; the magnetic field generator is turned off, and the printing head continues to move upwards, separating the grid line paste from the opening area, and after sintering, a trapezoidal metal grid line with a narrower top and wider bottom cross-section is formed on the silicon wafer surface. The metal grid line produced by this method has advantages in improving aspect ratio, reducing cost, improving light reflection utilization, and improving cell efficiency.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, specifically to a soft-contact printing method and a soft-contact printing mold for photovoltaic cell grid line paste. Background Technology

[0002] Currently, cost reduction and efficiency improvement have become the main focus for Topcon cells (Tunnel Oxide Passivating Contact, a type of photovoltaic cell that uses N-type silicon as a substrate and improves cell performance through tunneling oxide passivation contacts). Under current high cost pressures, reducing silver consumption (silver paste is mainly used to prepare metal grid lines or metal electrodes, but silver paste is expensive) has become one of the main means of cost reduction: mainly by reducing the number of grid lines (as shown in publication number CN220253256U) and reducing the grid line aspect ratio (as shown in publication number CN113212017A). However, these cost reduction methods will lead to a loss of cell efficiency. For example, if the number of grid lines is reduced from 180 to 170, although this can reduce the amount of silver paste used and lower the cost, it will also result in a loss of fill factor (FF), thus leading to a decrease in cell efficiency.

[0003] Furthermore, to control metallization costs, existing metallization methods for metal grids or metal electrodes typically involve first printing grid paste (such as silver paste) onto the metallization grid area on the silicon wafer surface, followed by high-temperature sintering to form patterned metal grids or metal electrodes. As shown in publication CN113212017A, the grid paste printing usually employs screen printing. Its basic principle is to transfer the grid paste onto the silicon wafer through the mesh or openings within the screen printing plate (i.e., the stencil). During screen printing, the stencil is placed at a predetermined position on the silicon wafer surface. Grid paste is poured into one end of the stencil, and a squeegee applies downward pressure to the grid paste area on the stencil, moving it towards the other end of the stencil, forcing the grid paste through the mesh or openings onto the silicon wafer.

[0004] However, during the process of applying downward pressure to the grid line paste area on the screen by the squeegee, the screen is prone to deformation and displacement, resulting in grid line paste widening (that is, the line width of the grid line paste on the silicon wafer surface is usually larger than the actual opening width of the screen). Therefore, it is difficult to further reduce the line width of the grid line paste produced by the screen printing method. Consequently, the grid line paste consumption and battery efficiency cannot be guaranteed simultaneously using the existing screen printing method, making it difficult to achieve both battery cost and efficiency. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a soft contact printing method and soft contact printing mold for photovoltaic cell grid line paste.

[0006] Based on this, the present invention discloses a soft-contact printing method for photovoltaic cell grid line paste, comprising the following steps:

[0007] S1. Mold making: The mold includes a printing head and a drive unit connected to the printing head, the drive unit driving the printing head to move up and down; the printing head includes a pusher, a magnetic field generator that drives the pusher to move downward, and a paste filling cavity for receiving gate line paste; the pusher is installed on the upper part of the paste filling cavity; the paste filling cavity includes a plurality of opening areas for the gate line paste to overflow from its bottom surface and be printed onto the silicon wafer surface, the cross-section of the opening area is a trapezoidal shape that is narrow at the top and wide at the bottom;

[0008] S2. Place the gate line paste into the paste filling cavity and place the silicon wafer below the mold, so that the metallized gate line area on the surface of the silicon wafer is aligned with the opening area.

[0009] S3. The driving component moves the printing head down to bring it closer to the silicon wafer surface. When the printing head moves down to a certain gap with the silicon wafer surface, the printing head stops moving down.

[0010] S4. The magnetic field generator drives the thruster downward by using magnetic force, so that the thruster pushes the grid slurry in the slurry filling cavity downward and overflows from the bottom surface of the opening area.

[0011] S5. The driving component moves the printing head upward and makes the distance between the bottom surface of the opening area and the silicon wafer surface less than the distance that the pusher pushes the grid line paste downward, so that the overflowing grid line paste leaves the mold and contacts the silicon wafer surface.

[0012] S6. Turn off the magnetic field generator. The drive unit continues to move the printing head up so that the grid line paste is completely separated from the opening area. After sintering, a metal grid line with a trapezoidal cross-section that is narrow at the top and wide at the bottom is formed on the silicon wafer surface.

[0013] Preferably, the number of opening regions is the same as the number of metal gate lines on the silicon wafer surface, and the number of opening regions is 150-320.

[0014] More preferably, the number of opening regions is 200-280.

[0015] Preferably, the upper side of the trapezoidal cross-section of the opening region has a length of 4-5 μm, the lower side has a length of 7-9 μm, and the height of the trapezoid is 4-12 μm.

[0016] Preferably, the magnetic field generator includes a wire, a fixing member mounted above the thruster, and a magnetic structure disposed on the thruster; the wire is connected to an external power source; the fixing member is fixedly connected to the wire so that the wire is mounted above the thruster through the fixing member, and the wire is located above the magnetic structure.

[0017] Preferably, the propeller is a rubber propeller that fits against the side wall of the slurry filling cavity.

[0018] Preferably, in step S6, the width of the metal grid line is 5-12 μm and its height is 3-10 μm.

[0019] More preferably, in step S3, the printing head stops moving downwards when the gap between the printing head and the silicon wafer surface is 2-3 μm.

[0020] More preferably, the distance by which the pusher moves the grid slurry downward is the height of the metal grid before sintering;

[0021] When the height of the metal grid line before sintering is 6-10 μm, the upward movement distance of the printing head in step S5 is 3-7 μm.

[0022] The present invention also discloses a soft contact printing mold for photovoltaic cell grid line paste, which is the mold used in the soft contact printing method for photovoltaic cell grid line paste described above in the present invention.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects:

[0024] Compared to existing screen printing (where the screen makes hard contact with the silicon wafer surface: the screen needs to be placed on the wafer surface, and the squeegee needs to apply downward pressure to the grid line paste area on the screen, which easily leads to screen deformation and displacement), the soft-contact printing method of this invention enables soft-contact printing of the grid line paste on the silicon wafer surface. During the printing process, the grid line paste does not expand, thus effectively avoiding the grid line paste widening phenomenon that occurs in existing screen printing. This allows for the printing of finer grid line paste on the silicon wafer surface, resulting in extremely fine and high-resolution metal grid lines after sintering, further improving the aspect ratio of the metal grid lines. This not only further reduces the amount of grid line paste used and the cost of the metal grid lines, but the finer metal grid lines also reduce light obstruction, increasing the absorption and utilization of sunlight by the battery, thus contributing to improved battery efficiency.

[0025] Moreover, compared with existing electrically propelled grid line paste printing methods, this invention uses a magnetic field force to push the grid line paste downwards, which can further save energy, reduce costs, improve thrust control accuracy and printing accuracy, and also improve propulsion efficiency and printing efficiency.

[0026] At the same time, the present invention also utilizes an opening area with a cross-section that is narrower at the top and wider at the bottom in a trapezoidal shape, so that the cross-section of the metal grid wire is also narrower at the top and wider at the bottom in a trapezoidal shape; therefore, it can also increase the reflection and reuse of sunlight on the side of the metal grid wire, collect more photocurrent, and further improve battery efficiency. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural schematic diagram of a soft contact printing device for photovoltaic cell grid line paste according to this embodiment.

[0028] Figure 2 This is a side view of the magnetic structure on the pusher in a soft contact printing device for photovoltaic cell grid line paste according to this embodiment.

[0029] Figure 3 This is a schematic diagram of the cross-sectional structure after step S5 in a soft contact printing method for photovoltaic cell grid line paste according to this embodiment.

[0030] Explanation of reference numerals: 1. Drive unit; 2. Print head; 21. Magnetic field generator; 211. Wire; 212. Fixing component; 213. Magnetic structure; 22. Pusher; 23. Slurry filling cavity; 231. Opening area; 3. Silicon wafer; 31. Metal grid line before sintering. Detailed Implementation

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example

[0033] This embodiment describes a soft-contact printing method for photovoltaic cell grid line paste. See also: Figure 1-3 It includes the following steps:

[0034] Step S1: Fabricate a soft-contact printing mold for photovoltaic cell grid line paste as shown in this embodiment:

[0035] The soft-contact printing mold includes a printing head 2 and a driving component 1; the driving component 1 is connected to the printing head 2 to drive the printing head 2 to move up and down, so that the printing head 2 can approach or move away from the surface of the silicon wafer 3. The driving component 1 is preferably a motor.

[0036] The printing head 2 includes a pusher 22, a magnetic field generator 21, and a paste filling cavity 23 for containing grid line paste. The magnetic field generator 21 is connected to the pusher 22 to drive the pusher 22 downward. The pusher 22 is mounted on the upper part of the paste filling cavity 23, and the paste filling cavity 23 includes a plurality of sequentially spaced opening regions 231 (e.g., ...). Figure 1 , 3(As shown); In this way, the pusher 22, under the action of the magnetic field, can push the grid line paste in the paste filling cavity 23 downward, so that the downwardly moving grid line paste overflows from the bottom surface of the opening region 231 and is printed onto the surface of the silicon wafer 3. Furthermore, the cross-section of the opening region 231 (this cross-section refers to the cross-section in the width direction of the opening region 231) is a trapezoidal shape that is narrower at the top and wider at the bottom, so that the cross-section of the printed and sintered metal grid lines is also a trapezoidal shape that is narrower at the top and wider at the bottom (as shown). Figure 3 (As shown).

[0037] In existing screen printing, the screen needs to be placed on the silicon wafer surface, and a squeegee needs to apply downward pressure to the grid line paste area on the screen, forcing the grid line paste through the mesh of the screen onto the silicon wafer surface. Therefore, in the existing screen printing process, the screen and silicon wafer surface are in hard contact. During the downward pressure applied by the squeegee to the grid line paste area, the screen is prone to deformation and displacement, leading to grid line paste widening (i.e., the line width of the grid line paste on the silicon wafer surface is usually larger than the actual opening width of the screen).

[0038] In this embodiment, the mold is formed by the cooperation of the aforementioned driving component 1, magnetic field generator 21, pusher 22, paste filling cavity 23 and opening area 231. During the printing process, the driving component 1 can first drive the printing head 2 to approach (but not contact) the surface of the silicon wafer 3. Then, the pusher 22 pushes the grid line paste in the paste filling cavity 23 downward under the action of magnetic field force and overflows from the bottom surface of the opening area 231. The driving component 1 then drives the printing head 2 upward, thereby causing the overflowing grid line paste to leave the mold and contact the surface of the silicon wafer 3. Thus, during the printing of grid line paste on the surface of silicon wafer 3 using this mold, the entire mold (such as the printing head 2) does not contact the surface of silicon wafer 3, and the mold does not need to apply pressure to the printed grid line paste. That is, using this mold enables soft contact printing of the grid line paste on the surface of silicon wafer 3, and the grid line paste will not expand during the printing process. Therefore, it can effectively avoid the grid line paste widening phenomenon that occurs in existing screen printing, and can print grid line paste with a finer width on the surface of silicon wafer 3. After sintering, extremely fine and high metal grid lines can be obtained, which can further improve the aspect ratio of the metal grid lines. In this way, it can further reduce the amount of grid line paste (such as silver paste) used, reduce the cost of metal grid lines, and increase the absorption and utilization of sunlight by the battery (because the width of the metal grid lines is finer, it can further reduce the shading of sunlight by the metal grid lines), which helps to improve the battery efficiency.

[0039] Moreover, compared with the existing electric propulsion grid line paste printing method, this embodiment uses the cooperation of magnetic field generator 21 and propeller 22 to make propeller 22 push grid line paste downward under the action of magnetic field force, which can further save energy, reduce costs, improve thrust control accuracy and printing accuracy, and also improve propulsion efficiency and printing efficiency.

[0040] At the same time, this embodiment also utilizes an opening region 231 with a cross-section that is narrower at the top and wider at the bottom in a trapezoidal shape, so that the cross-section of the printed and sintered metal grid lines is also narrower at the top and wider at the bottom in a trapezoidal shape; therefore, it can also increase the reflection and reuse of sunlight on the side of the metal grid lines, collect more photocurrent, and further improve battery efficiency.

[0041] In practice, a mold with the same number of opening regions 231 is made according to the number of metal grid lines on the surface of silicon wafer 3. The number of opening regions 231 can be 150-320.

[0042] In this embodiment, the number of opening regions 231 is preferably 200-280. Under the premise of fabricating extremely fine and high-density metal grid lines and reducing the cost of metal grid lines, the number of metal grid lines on the surface of the silicon wafer 3 can be appropriately increased to increase the metal grid line density on the surface of the silicon wafer 3. This extremely fine and high-density grid improves the fill factor of the battery and further enhances battery efficiency.

[0043] Specifically, the upper side length of the trapezoidal cross-section of the opening region 231 is 4-5 μm, the lower side length of the trapezoidal cross-section of the opening region 231 is 7-9 μm, and the height of the trapezoidal cross-section of the opening region 231 is 4-12 μm. This ensures that the metal grid lines printed and sintered by the soft-contact printing method of this embodiment have extremely fine and high characteristics; the width of the metal grid lines is 5-12 μm, and the height of the metal grid lines is 3-10 μm (preferably 6-10 μm).

[0044] After printing and sintering, due to factors such as gravity, the width of the metal grid lines is usually slightly larger than the width of the opening region 231, and the height of the metal grid lines is usually slightly smaller than the height of the opening region 231.

[0045] Specifically, see Figure 1-2 The magnetic field generator 21 includes a wire 211, a fixing member 212, and a magnetic structure 213 disposed on the thruster 22. For example, the magnetic structure 213 can be a layer of magnetic material disposed on the upper surface of the thruster 22 (such as...). Figure 2(As shown). A fixing member 212 is installed above the pusher 22, and the fixing member 212 is fixedly connected to the wire 211. Preferably, each end of the wire 211 can be fixedly connected to a fixing member 212, so that the wire 211 is firmly installed above the pusher 22 by the fixing member 212. There can be several wires 211, which are spaced apart above the pusher 22, and are electrically connected to an external power source after being connected in parallel and / or in series, so as to be powered by an external power source. Furthermore, the wires 211 are located above the magnetic structure 213. In this way, a constant magnetic field can be generated above the pusher 22 by a constantly changing current, enabling the pusher 22 to accurately and efficiently push the gate line paste in the paste filling cavity 23 downwards, overflow, and contact the surface of the silicon wafer 3 under the action of the constant magnetic field force, thereby enabling the gate line paste to achieve precise and efficient soft contact printing on the surface of the silicon wafer 3.

[0046] In actual operation, the magnetic structure 213 moves downward along with the pusher 22 and the grid line slurry in the slurry filling cavity 23, while the wire 211 and the fixing member 212 do not move downward along with the pusher 22 and the grid line slurry in the slurry filling cavity 23. The magnetic structure 213 is made of magnet or other materials containing permanent magnets (such as nickel magnets, nickel-iron magnets, etc.).

[0047] Specifically, the pusher 22 is preferably a rubber pusher 22 that fits against the side wall of the slurry filling cavity 23. The rubber pusher 22 can fit tightly against the side wall of the slurry filling cavity 23, which can ensure that the grid slurry in the slurry filling cavity 23 is fully and effectively squeezed to effectively ensure the downward movement of the grid slurry.

[0048] Step S2: Place the gate line paste into the paste filling cavity 23 and place the silicon wafer 3 below the mold, so that the metallized gate line area on the surface of the silicon wafer 3 is aligned with the opening area 231.

[0049] In step S3, the driving component 1 moves the printing head 2 downward to bring it closer to the surface of the silicon wafer 3. When the printing head 2 moves down to a certain gap with the surface of the silicon wafer 3, the printing head 2 stops moving downward. This gap between the printing head 2 and the surface of the silicon wafer 3 is necessary to allow the mold to be used to achieve soft contact printing of the grid line paste on the surface of the silicon wafer 3.

[0050] Specifically, in step S3, when the printing head 2 moves down to a gap of 2-3 μm with the surface of the silicon wafer 3, the printing head 2 stops moving down. The size of this gap should not be too large, so as to prevent the subsequent overflow of gate line paste from falling onto the surface of the silicon wafer 3 from a height and causing deformation; the size of this gap should also not be too small, so as to prevent the subsequent overflow of gate line paste from being squeezed between the pusher 22 and the surface of the silicon wafer 3, thus affecting the further improvement of the aspect ratio of the sintered metal gate lines.

[0051] Step S4: The magnetic field generator 21 drives the thruster 22 to move downward by generating a magnetic field, so that the thruster 22 pushes the grid slurry in the slurry filling cavity 23 downward and overflows from the bottom surface of the opening region 231.

[0052] Step S5: The driving component 1 moves the printing head 2 upward, making the distance between the bottom surface of the opening area 231 and the surface of the silicon wafer 3 less than the distance the pusher 22 pushes the grid line paste downward (the distance the pusher 22 pushes the grid line paste downward is the height of the metal grid line 31 before sintering, and the height of the metal grid line 31 before sintering is the height of the grid line paste printed onto the surface of the silicon wafer 3 in step S6 below), so as to ensure that the overflowing grid line paste can detach from the mold and contact the surface of the silicon wafer 3 (e.g., Figure 3 As shown in the figure, this allows the contact force between the silicon wafer 3 surface and the gate line paste to be greater than the sum of the frictional forces between the gate line pastes and between the gate line paste and the sidewall of the opening region 231, so that the gate line paste and the opening region 231 can be completely separated more quickly and efficiently.

[0053] When the height of the metal grid line 31 before sintering is preferably 6-10 μm, the upward movement distance of the printing head 2 in step S5 is preferably 3-7 μm.

[0054] Step S6: Turn off the magnetic field generator 21, and drive the printing head 2 to move upward, so that the grid line paste is completely separated from the opening area 231, so as to complete the soft contact printing of the grid line paste on the surface of the silicon wafer 3; after sintering, a metal grid line with a trapezoidal cross-section that is narrow at the top and wide at the bottom is formed on the surface of the silicon wafer 3.

[0055] In summary, the mold of this embodiment can perform soft-contact printing of photovoltaic cell grid line paste on the surface of silicon wafer 3 as described in steps S1-S6 above. This effectively avoids the grid line paste widening phenomenon that occurs in existing screen printing, and after sintering, it can obtain extremely fine and high metal grid lines, which can further improve the aspect ratio of the metal grid lines, thereby reducing the amount of grid line paste used and the cost of the metal grid lines. In addition, the thinner metal grid lines block less sunlight, which can increase the absorption and utilization of sunlight by the battery and help improve battery efficiency. Moreover, the pusher 22 of this mold uses magnetic force to push the grid line paste downward. Compared with the existing electric propulsion grid line paste printing method, it can further save energy, reduce costs, improve thrust control accuracy and printing accuracy, and improve propulsion efficiency and printing efficiency. At the same time, it can make the cross-section of the printed and sintered metal grid lines trapezoidal with a narrow top and a wide bottom, which can also increase the reflection and reuse of sunlight on the side of the metal grid lines, collect more photocurrent, and further improve battery efficiency.

[0056] Furthermore, while fabricating extremely fine and high-density metal grid lines and reducing their cost, the number of metal grid lines on the surface of silicon wafer 3 can be appropriately increased to enhance the grid line density. This extremely fine and high-density grid improves the fill factor of the cell, further enhancing cell efficiency. Additionally, by optimizing the gap in step S3 and the upward movement distance of the printhead 2 in step S5, the grid line paste can be printed more precisely and efficiently on the surface of silicon wafer 3, achieving better soft-contact printing and further improving the aspect ratio and quality of the metal grid lines.

[0057] Therefore, the metal grid lines produced by the soft contact printing mold and the soft contact printing method used in this embodiment have advantages in improving aspect ratio, reducing cost, improving light reflection and light utilization, improving printing accuracy and printing efficiency, and improving battery efficiency.

[0058] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0059] The technical solution provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A soft-contact printing method for photovoltaic cell grid line paste, characterized in that, The steps include the following: S1. Mold making: The mold includes a printing head and a drive unit connected to the printing head, the drive unit driving the printing head to move up and down; the printing head includes a pusher, a magnetic field generator that drives the pusher to move downward, and a paste filling cavity for receiving grid line paste; the pusher is installed on the upper part of the paste filling cavity; the paste filling cavity includes a number of opening areas for grid line paste to overflow from its bottom surface and be printed onto the silicon wafer surface, the cross-section of the opening area is a trapezoidal shape that is narrow at the top and wide at the bottom, and the number of opening areas is the same as the number of metal grid lines on the silicon wafer surface; S2. Place the gate line paste into the paste filling cavity and place the silicon wafer below the mold, so that the metallized gate line area on the surface of the silicon wafer is aligned with the opening area. S3. The driving component moves the printing head down to bring it closer to the silicon wafer surface. When the printing head moves down to a certain gap with the silicon wafer surface, the printing head stops moving down. S4. The magnetic field generator drives the thruster downward by using magnetic force, so that the thruster pushes the grid slurry in the slurry filling cavity downward and overflows from the bottom surface of the opening area. S5. The driving component moves the printing head upward and makes the distance between the bottom surface of the opening area and the silicon wafer surface less than the distance that the pusher pushes the grid line paste downward, so that the overflowing grid line paste leaves the mold and contacts the silicon wafer surface. S6. Turn off the magnetic field generator. The drive unit continues to move the printing head up so that the grid line paste is completely separated from the opening area. After sintering, a metal grid line with a trapezoidal cross-section that is narrow at the top and wide at the bottom is formed on the silicon wafer surface.

2. The soft-contact printing method for photovoltaic cell grid line paste according to claim 1, characterized in that, The number of opening regions is 150-320.

3. The soft-contact printing method for photovoltaic cell grid line paste according to claim 2, characterized in that, The number of opening regions is 200-280.

4. The soft-contact printing method for photovoltaic cell grid line paste according to claim 1, characterized in that, The cross-section of the opening region has a trapezoidal upper side length of 4-5 μm, a trapezoidal lower side length of 7-9 μm, and a trapezoidal height of 4-12 μm.

5. The soft-contact printing method for photovoltaic cell grid line paste according to claim 1, characterized in that, The magnetic field generator includes a wire, a fixture mounted above the thruster, and a magnetic structure disposed on the thruster; the wire is connected to an external power source; the fixture is fixedly connected to the wire so that the wire is mounted above the thruster and the wire is located above the magnetic structure.

6. The soft-contact printing method for photovoltaic cell grid line paste according to claim 1, characterized in that, The propeller is a rubber propeller that fits into the side wall of the slurry filling cavity.

7. The soft-contact printing method for photovoltaic cell grid line paste according to claim 1, characterized in that, In step S6, the width of the metal grid line is 5-12 μm and its height is 3-10 μm.

8. A soft-contact printing method for photovoltaic cell grid line paste according to claim 1 or 7, characterized in that, In step S3, the printing head stops moving downwards when the gap between the printing head and the silicon wafer surface is 2-3 μm.

9. A soft-contact printing method for photovoltaic cell grid line paste according to claim 1 or 7, characterized in that, The distance that the pusher pushes the grid slurry downward is the height of the metal grid before sintering; When the height of the metal grid line before sintering is 6-10 μm, the upward movement distance of the printing head in step S5 is 3-7 μm.

10. A soft-contact printing mold for photovoltaic cell grid line paste, characterized in that, It is a mold used in the soft contact printing method of photovoltaic cell grid line paste according to any one of claims 1-9.

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