Screen plate for solar cell electrode printing

Abstract

The utility model relates to the field of solar cell printing, and discloses a screen plate for solar cell electrode printing, which comprises an outer frame and at least one printing area, the outer frame is internally provided with at least one printing area, and each printing area comprises a screen plate and a porous membrane arranged below the screen plate; the mesh wire plate is composed of a grid array, a plurality of through holes vertically penetrating through the porous membrane are formed in the porous membrane, the through holes are composed of upper through holes with the top end width larger than the bottom end width and lower through holes with the top end width smaller than the bottom end width, and the bottom ends of the upper through holes are communicated with and matched with the top ends of the lower through holes. Through the design of the through hole structure and arrangement of the porous film in the printing area, the printed metal electrodes are of a structure with the top end being a sharp corner and the side face being a bevel edge, reasonable distances are kept between the metal electrodes, light refraction is facilitated, meanwhile, the light receiving area is increased, the light receiving rate of the metal electrodes is increased, and the service life of the metal electrodes is prolonged. And the photoelectric conversion efficiency of the cell is improved.

Description

Technical Field

[0001] The utility model relates to the field of solar cell printing, in particular to a screen plate used for printing solar cell electrodes. Background Art

[0002] Solar cells can directly convert sunlight into electrical energy, and are an effective means of solving the problem of energy shortage. In the production process of solar cells, screen printing is an important process to achieve energy conversion. Metal electrodes are printed on semiconductor materials through printing screens. Semiconductor materials printed with metal electrodes will produce photovoltaic effects under the irradiation of sunlight, thereby converting natural light energy into electrical energy that can be used by people.

[0003] The top surface of the metal electrode printed by the screen used in the industry is mostly flat. The metal electrode with a flat top surface is not conducive to light refraction, which causes the metal electrode to lose light receiving rate, resulting in low photoelectric conversion efficiency of the cell. At present, we are in the era of dense grids, and the number of fine grids on the surface of the cell increases, which will further reduce the light receiving area of ​​the cell. Therefore, finding a screen that can increase the light receiving rate of the metal electrode is a problem that needs to be solved at present. Utility Model Content

[0004] In order to solve the technical problem of low light receiving rate of the above-mentioned metal electrodes, the utility model provides a screen for printing solar cell electrodes. By designing the through holes of the porous membrane in the printing area, the top of the printed metal electrode is sharp, which increases the light receiving rate of the metal electrode and improves the photoelectric conversion efficiency of the battery cell.

[0005] The specific technical scheme of the utility model is: a screen plate for printing solar cell electrodes, comprising an outer frame and a printing area, at least one printing area is arranged in the outer frame, the printing area comprises a mesh plate and a porous membrane arranged below the mesh plate; the mesh plate is composed of a grid array; a plurality of through holes are arranged in the porous membrane vertically penetrating the porous membrane, the through holes are composed of an upper through hole with a top width greater than a bottom width and a lower through hole with a top width less than a bottom width, the bottom end of the upper through hole is connected and adapted to the top end of the lower through hole.

[0006] The upper through hole is contracted inward, the lower through hole is expanded outward, and the upper and lower through holes are connected. This structure enables the slurry to contact the battery cell through the porous membrane. Because the width of the lower through hole varies, the inner wall of the porous membrane can give the slurry a downward extrusion force to adhere it to the battery cell. After printing is completed, the slurry is semi-solidified, and the printing area is lifted upward. The slurry in the upper through hole and the slurry in the lower through hole will be separated due to the tearing force. The slurry on the separation surface will produce an upward sharp corner due to ductility, and after sintering, an electrode with a triangular cross-section is formed. Multiple printing areas can be set in the outer frame to process multiple battery cells and improve processing efficiency. The material of the porous membrane is PI.

[0007] Preferably, the ratio of the bottom width to the top width of the upper through hole is 1 / 3 to 2 / 3; the bottom of the upper through hole coincides with the top of the lower through hole, and the upper through hole and the lower through hole are symmetrically arranged about the bottom of the upper through hole.

[0008] The upper through hole and the lower through hole are symmetrically arranged, and the through hole is hourglass-shaped as a whole. The ratio of the bottom width to the top width of the upper through hole is in the range of 1 / 3 to 2 / 3, which is conducive to the entry and separation of the slurry; the ratio of the top width to the bottom width of the lower through hole is 1 / 3 to 2 / 3, which is conducive to the adhesion of the slurry to the battery cell.

[0009] Preferably, the ratio of the bottom width to the top width of the upper through hole is 1 / 2, the bottom surface of the upper through hole coincides with the top surface of the lower through hole, and the upper through hole and the lower through hole are symmetrically arranged with respect to the bottom surface of the upper through hole.

[0010] Preferably, the through holes are arranged at equal intervals along the side of the porous membrane and horizontally penetrate the porous membrane or are arranged at equal intervals to form queues, and each queue is arranged at equal intervals along the side of the porous membrane.

[0011] The plurality of through holes are arranged at equal intervals along the side of the porous membrane (1.4) and horizontally penetrate the porous membrane (1.4); or, the plurality of through holes include a plurality of queues arranged at equal intervals along the side of the porous membrane (1.4), and the through holes in each queue are arranged at equal intervals.

[0012] The electrodes made from the above structure are arranged at equal intervals, which is beneficial to the refraction of light and increases the light receiving rate of the electrodes.

[0013] Preferably, the bottom width of the upper through hole is 0.5-1.5 mm.

[0014] The electrodes need to maintain a certain distance. If the through hole is too small or too large, it will affect the density of the grid lines formed by the electrode, and then affect the light receiving rate of the electrode. At the same time, the reasonable setting of the number and width of electrodes can improve the printing quality.

[0015] Preferably, the angle between the side edge and the bottom end of the lower through hole is 45-75°.

[0016] The electrode bevel produced in this way has high light refraction efficiency.

[0017] Preferably, the angle between the side and the bottom of the lower through hole is 60°.

[0018] Preferably, the distance between adjacent queues is not less than the bottom width of the lower through hole.

[0019] If the electrode spacing is too narrow, the density of the grid lines formed will be high, resulting in a reduction in the light receiving area of ​​the cell. The spacing between adjacent queues and the spacing between adjacent through holes in the queue do not have to be equal.

[0020] Preferably, the thickness of the porous membrane is greater than the thickness of the mesh plate.

[0021] Preferably, the mesh plate is composed of square grids arranged at equal intervals, and the grid width is 0.3 to 0.7 mm.

[0022] Through this design, the amount of ink passing through the printing area can be more uniform and reasonable, so that the linear saturation of the printing is higher and the photoelectric conversion efficiency of the screen is improved.

[0023] Preferably, the mesh plate is composed of square grids arranged at equal intervals, and the grid width is 0.5 mm.

[0024] Preferably, the mesh plate is made of stainless steel.

[0025] During printing, the mesh plate needs to rub against the scraper. The use of stainless steel can improve the wear resistance of the printing area.

[0026] Preferably, two printing areas are provided in parallel in the outer frame, with a gap between the two printing areas.

[0027] There is a gap between each printing area to improve the printing quality when multiple cells are printed at the same time.

[0028] Compared with the prior art, the utility model has the following advantages:

[0029] The utility model designs the through-hole structure and arrangement of the porous membrane in the printing area so that the printed metal electrode has a structure with a sharp top and a beveled side. A reasonable spacing is maintained between the metal electrodes, which is beneficial to light refraction. The grid line density formed by the metal electrodes is reasonable, and the light-receiving area of ​​the battery cell is large, which helps to improve the light-receiving rate of the metal electrode, thereby improving the photoelectric conversion efficiency of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall structure of the screen plate in Example 1.

[0031] Figure 2 It is a schematic diagram of the structure of the printing area in Example 1.

[0032] Figure 3 Schematic diagram of the electrode prepared in Example 1.

[0033] Figure 4 It is a schematic diagram of the use state of the utility model.

[0034] The figures are marked as follows: 1-printing area, 1.3-mesh plate, 1.4-porous membrane, 1.4.1-upper through hole, 1.4.2-lower through hole, 4-battery cell, 5-scraper, 6-slurry, 7-working table, 8-outer frame, 9-electrode. DETAILED DESCRIPTION

[0035] The present invention is further described below in conjunction with the embodiments. The devices, connection structures and methods involved in the present invention are all devices, connection structures and methods known in the art unless otherwise specified.

[0036] Example 1

[0037] like Figures 1 to 4 As shown, the utility model provides a screen for printing solar cell electrodes, including an outer frame 8 and a printing area 1. The outer frame 8 is rectangular in top view, and two rectangular printing areas 1 are arranged inside. The printing areas 1 are arranged parallel to the frame edge of the outer frame 8. The long sides of the two printing areas 1 are opposite, with a gap in the middle, and the four sides of the printing areas 1 are spaced from the outer frame 8. The printing area 1 is a double-layer structure, with a mesh plate 1.3 on the upper layer and a porous membrane 1.4 on the lower layer. The mesh plate 1.3 is composed of an array of square grids with equal spacing. A plurality of through holes are arranged in the porous membrane 1.4. The through holes penetrate the porous membrane 1.4 from top to bottom, and are composed of an upper through hole 1.4.1 and a lower through hole 1.4.2. The width of the top of the upper through hole 1.4.1 is greater than the width of the bottom, and the width of the top of the lower through hole 1.4.2 is less than the width of the bottom. The bottom of the upper through hole 1.4.1 coincides with and is connected to the top of the lower through hole 1.4.2, and the two have the same area and size. The upper through hole 1.4.1 and the lower through hole 1.4.2 are symmetrically arranged about the bottom of the upper through hole 1.4.1, and the through holes are equally spaced. The porous membrane cross section 1.4 between the through holes forms a hexagonal structure.

[0038] In the present embodiment, a plurality of through holes penetrate the porous membrane 1.4 from front to back, and are arranged equidistantly along the short side of the porous membrane 1.4, the distance between adjacent through holes is the same as the bottom width of the lower through hole 1.4.2, and the porous membrane cross section 1.4 between adjacent through holes forms a regular hexagonal structure. The bottom width of the upper through hole 1.4.1 is half of the top width, the bottom width of the upper through hole 1.4.1 is 1.0mm, and the top width is 2.0mm. The bottom width of the lower through hole 1.4.2 is 2.0mm, the top width is 1.0mm, and the angle between the side of the lower through hole and the bottom is 60°. The material of the porous membrane 1.4 is PI. The square grid width in the mesh plate 1.3 is 0.5mm, and there is no corresponding relationship between the grid and the top 1.4 of the upper through hole. The mesh plate 1.3 is made of stainless steel, and the thickness of the mesh plate 1.3 is less than the thickness of the porous membrane 1.4.

[0039] In this embodiment, the upper through hole 1.4.1 is inwardly contracted, the lower through hole 1.4.2 is outwardly expanded, the upper and lower through holes are connected and centrally symmetrical, so that the through hole is hourglass-shaped as a whole. The electrode 9 made by this structure has a bevel, which helps to refract light to increase the light receiving rate of the electrode 9. At the same time, due to the width variation between the upper and lower end faces and the waist of the through hole, during printing, the inner wall of the porous membrane 1.4 can give the slurry 6 in the lower through hole 1.4.2 a downward extrusion force to make it adhere to the battery cell; after printing is completed, the screen is lifted, and this structure helps to generate a tearing force inside the semi-solidified slurry 6, so that the slurry 6 in the upper through hole 1.4.1 and the slurry 6 in the lower through hole 1.4.2 are separated, and the slurry on the separation surface will produce an upward sharp corner due to ductility, and after sintering, an electrode 9 with a triangular cross section will be formed. In addition, the ratio of the width of the upper and lower end faces of the through hole to the width of the waist is kept within a certain range, which is conducive to the entry and separation of the slurry 6. By controlling the size of the through holes and setting the spacing, the electrodes 9 are kept at a certain distance, so that the grid line density formed by the electrodes 9 is reasonable, which is not only conducive to light refraction, but also increases the light receiving area of ​​the cell and improves the photoelectric conversion efficiency of the cell.

[0040] The operation process of the screen in this embodiment is as follows. Figure 3 and 4 First, place the cell 4 on the workbench 7, and the cell 4 is fixed on the workbench 7 by adsorption. Then, press the screen down to a height of 50-100um from the cell 4, align the printing area 1 with the cell, pour the slurry 6 on the printing area 1, and scraper 5 scrapes the slurry 6 into the mesh plate 1.3. Driven by the scraper 5, the slurry 6 flows into the upper through hole 1.4.1 through the mesh plate 1.3. Then, the slurry 6 in the upper through hole 1.4.1 is squeezed by the upper slurry 6 and flows into the lower through hole 1.4.2. The slurry 6 in the lower through hole 1.4.2 is squeezed by the upper slurry 6 and the inner wall of the porous membrane 1.4, and adheres to the cell 4. After printing is completed, the scraper 5 and the screen are lifted upwards. At this time, the slurry 6 is semi-solidified. The slurry 6 in the lower through hole 1.4.2 adheres to the battery cell due to extrusion and its own adhesion. The slurry 6 in the upper through hole 1.4.1 and the slurry 6 in the lower through hole 1.4.2 will be separated due to the tearing force. The slurry 6 on the separation surface will produce an upward sharp corner due to its ductility. The slurry 6 adhered to the battery cell 4 is sintered to form an electrode 9 with a triangular cross-section.

[0041] Example 2

[0042] The utility model provides a screen for printing solar cell electrodes, comprising an outer frame 8 and a printing area 1. The outer frame 8 is rectangular in top view, and a rectangular printing area 1 is provided in the inner central area. The printing area 1 is arranged parallel to the frame edge of the outer frame 8, and the four sides of the printing area 1 are spaced from the outer frame 8. The printing area 1 is a double-layer structure, with a mesh plate 1.3 on the upper layer and a porous membrane 1.4 on the lower layer. The mesh plate 1.3 is composed of an array of diamond grids with equal spacing. A number of through holes are arranged in the porous membrane 1.4. The through holes penetrate the porous membrane 1.4 from top to bottom, and are composed of an upper through hole 1.4.1 and a lower through hole 1.4.2. The width of the top of the upper through hole 1.4.1 is greater than the width of the bottom, and the width of the top of the lower through hole 1.4.2 is less than the width of the bottom. The bottom of the upper through hole 1.4.1 coincides with the top of the lower through hole 1.4.2 and is connected. The two have the same area and size. The upper through hole 1.4.1 and the lower through hole 1.4.2 are symmetrically arranged about the bottom of the upper through hole 1.4.1. The through holes are arranged at a certain interval, and the porous membrane cross-section 1.4 between the through holes forms a hexagonal structure.

[0043] In the present embodiment, a number of through holes are arranged at equal intervals along the long side of the porous membrane 1.4 to form a queue, and each queue is arranged at equal intervals along the short side of the porous membrane 1.4, and the spacing between adjacent queues is greater than the spacing between adjacent through holes in the queue, and the spacing between adjacent queues is greater than the bottom width of the lower through hole 1.4.2, and the porous membrane cross section 1.4 between adjacent through holes is a hexagonal structure. The bottom width of the upper through hole 1.4.1 is 1 / 3 of the top width, and the bottom width of the upper through hole 1.4.1 is 0.5mm, and the top width is 1.5mm. The bottom width of the lower through hole 1.4.2 is 1.5mm, the top width is 0.5mm, and the angle between the side of the lower through hole and the bottom is 75°. The material of the porous membrane 1.4 is PI. The width of the diamond grid in the mesh plate 1.3 is 0.3mm, and there is no corresponding relationship between the grid and the top 1.4 of the upper through hole. The mesh plate 1.3 is made of stainless steel, and the thickness of the mesh plate 1.3 is less than the thickness of the porous membrane 1.4.

[0044] In this embodiment, the upper through hole 1.4.1 is inwardly contracted, the lower through hole 1.4.2 is outwardly expanded, the upper and lower through holes are connected and centrally symmetrical, so that the through hole is hourglass-shaped as a whole. The electrode 9 made by this structure has a bevel, which helps to refract light to increase the light receiving rate of the electrode 9. At the same time, due to the width variation between the upper and lower end faces and the waist of the through hole, during printing, the inner wall of the porous membrane 1.4 can give the slurry 6 in the lower through hole 1.4.2 a downward extrusion force to make it adhere to the battery cell; after printing is completed, the screen is lifted, and this structure helps to generate a tearing force inside the semi-solidified slurry 6, so that the slurry 6 in the upper through hole 1.4.1 and the slurry 6 in the lower through hole 1.4.2 are separated, and the slurry on the separation surface will produce an upward sharp corner due to ductility, and after sintering, an electrode 9 with a triangular cross section will be formed. In addition, the ratio of the width of the upper and lower end faces of the through hole to the width of the waist is kept within a certain range, which is conducive to the entry and separation of the slurry 6. By controlling the size of the through holes and setting the spacing, the electrodes 9 are kept at a certain distance, so that the grid line density formed by the electrodes 9 is reasonable, which is not only conducive to light refraction, but also increases the light receiving area of ​​the cell and improves the photoelectric conversion efficiency of the cell.

[0045] The operation process of the screen in this embodiment is as follows. Figure 4 First, place the cell 4 on the workbench 7, and the cell 4 is fixed on the workbench 7 by adsorption. Then, press the screen down to a height of 50-100um from the cell 4, align the printing area 1 with the cell, pour the slurry 6 on the printing area 1, and scraper 5 scrapes the slurry 6 into the mesh plate 1.3. Driven by the scraper 5, the slurry 6 flows into the upper through hole 1.4.1 through the mesh plate 1.3. Then, the slurry 6 in the upper through hole 1.4.1 is squeezed by the upper slurry 6 and flows into the lower through hole 1.4.2. The slurry 6 in the lower through hole 1.4.2 is squeezed by the upper slurry 6 and the inner wall of the porous membrane 1.4, and adheres to the cell 4. After printing is completed, the scraper 5 and the screen are lifted upwards. At this time, the slurry 6 is semi-solidified. The slurry 6 in the lower through hole 1.4.2 adheres to the battery cell due to extrusion and its own adhesion. The slurry 6 in the upper through hole 1.4.1 and the slurry 6 in the lower through hole 1.4.2 will be separated due to the tearing force. The slurry 6 on the separation surface will produce an upward sharp corner due to its ductility. The slurry 6 adhered to the battery cell 4 is sintered to form an electrode 9 with a triangular cross-section.

[0046] Example 3

[0047] The utility model provides a screen for printing solar cell electrodes, comprising an outer frame 8 and a printing area 1. The outer frame 8 is rectangular in top view, and a square printing area 1 is provided in the inner central area. The printing area 1 is parallel to the frame edge of the outer frame 8, and the four sides of the printing area 1 are spaced from the outer frame 8. The printing area 1 is a double-layer structure, with a mesh plate 1.3 on the upper layer and a porous membrane 1.4 on the lower layer. The mesh plate 1.3 is composed of an array of square grids at equal intervals. The porous membrane 1.4 is provided with a plurality of through holes, which penetrate the porous membrane 1.4 from top to bottom and are composed of an upper through hole 1.4.1 and a lower through hole 1.4.2. The width of the top of the upper through hole 1.4.1 is greater than the width of the bottom, and the width of the top of the lower through hole 1.4.2 is less than the width of the bottom. The bottom of the upper through hole 1.4.1 overlaps and is connected with the top of the lower through hole 1.4.2, and the two have the same area and size. The width of the top of the upper through hole 1.4.1 is less than the width of the bottom of the lower through hole 1.4.2, and the distance from the top of the upper through hole 1.4.1 to the bottom is less than the distance from the top of the lower through hole 1.4.2 to the bottom. The through holes are equally spaced, and the porous membrane cross section 1.4 between the through holes forms a hexagonal structure.

[0048] In the present embodiment, the through holes penetrate the porous membrane 1.4 from front to back, and are arranged equidistantly along the side of the porous membrane 1.4, and the spacing distance is greater than the bottom width of the lower through hole 1.4.2, and the porous membrane cross section 1.4 between adjacent through holes is a hexagonal structure. The bottom width of the upper through hole 1.4.1 is 2 / 3 of the top width, the bottom width of the upper through hole 1.4.1 is 2.0mm, and the top width is 3.0mm. The bottom width of the lower through hole 1.4.2 is 3.8mm, the top width is 2.0mm, and the angle between the side of the lower through hole and the bottom is 45°. The material of the porous membrane 1.4 is PI. The square grid width in the mesh plate 1.3 is 0.7mm, and there is no corresponding relationship between the grid and the top 1.4 of the upper through hole. The mesh plate 1.3 is made of stainless steel, and the thickness of the mesh plate 1.3 is less than the thickness of the porous membrane 1.4.

[0049] In this embodiment, the upper through hole 1.4.1 is inwardly contracted, the lower through hole 1.4.2 is outwardly expanded, the upper and lower through holes are connected and centrally symmetrical, so that the through hole is hourglass-shaped as a whole. The electrode 9 made by this structure has a bevel, which helps to refract light to increase the light receiving rate of the electrode 9. At the same time, due to the width variation between the upper and lower end faces and the waist of the through hole, during printing, the inner wall of the porous membrane 1.4 can give the slurry 6 in the lower through hole 1.4.2 a downward extrusion force to make it adhere to the battery cell; after printing is completed, the screen is lifted, and this structure helps to generate a tearing force inside the semi-solidified slurry 6, so that the slurry 6 in the upper through hole 1.4.1 and the slurry 6 in the lower through hole 1.4.2 are separated, and the slurry on the separation surface will produce an upward sharp corner due to ductility, and after sintering, an electrode 9 with a triangular cross section will be formed. In addition, the ratio of the width of the upper and lower end faces of the through hole to the width of the waist is kept within a certain range, which is conducive to the entry and separation of the slurry 6. By controlling the size of the through holes and setting the spacing, the electrodes 9 are kept at a certain distance, so that the grid line density formed by the electrodes 9 is reasonable, which is not only conducive to light refraction, but also increases the light receiving area of ​​the cell and improves the photoelectric conversion efficiency of the cell.

[0050] The operation process of the screen in this embodiment is as follows. Figure 4 First, place the cell 4 on the workbench 7, and the cell 4 is fixed on the workbench 7 by adsorption. Then, press the screen down to a height of 50-100um from the cell 4, align the printing area 1 with the cell, pour the slurry 6 on the printing area 1, and scraper 5 scrapes the slurry 6 into the mesh plate 1.3. Driven by the scraper 5, the slurry 6 flows into the upper through hole 1.4.1 through the mesh plate 1.3. Then, the slurry 6 in the upper through hole 1.4.1 is squeezed by the upper slurry 6 and flows into the lower through hole 1.4.2. The slurry 6 in the lower through hole 1.4.2 is squeezed by the upper slurry 6 and the inner wall of the porous membrane 1.4, and adheres to the cell 4. After printing is completed, the scraper 5 and the screen are lifted upwards. At this time, the slurry 6 is semi-solidified. The slurry 6 in the lower through hole 1.4.2 adheres to the battery cell due to extrusion and its own adhesion. The slurry 6 in the upper through hole 1.4.1 and the slurry 6 in the lower through hole 1.4.2 will be separated due to the tearing force. The slurry 6 on the separation surface will produce an upward sharp corner due to its ductility. The slurry 6 adhered to the battery cell 4 is sintered to form an electrode 9 with a triangular cross-section.

[0051] The above description is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Any simple modification, change and equivalent structural transformation made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A screen for printing solar cell electrodes, comprising an outer frame (8) and a printing area (1), characterized in that: At least one printing area (1) is arranged in the outer frame (8), and the printing area (1) comprises a mesh plate (1.3) and a porous membrane (1.4) arranged below the mesh plate (1.3); the mesh plate (1.3) is composed of a grid array; a plurality of through holes are arranged in the porous membrane (1.4) and vertically penetrate the porous membrane (1.4), and the through holes are composed of an upper through hole (1.4.1) whose top width is greater than that of the bottom end, and a lower through hole (1.4.2) whose top width is less than that of the bottom end, and the bottom end of the upper through hole (1.4.1) is connected and matched with the top end of the lower through hole (1.4.2).

2. A screen for printing solar cell electrodes according to claim 1, characterized in that: The ratio of the bottom width to the top width of the upper through hole (1.4.1) is 1 / 3 to 2 / 3; the bottom of the upper through hole (1.4.1) coincides with the top of the lower through hole (1.4.2), and the upper through hole (1.4.1) and the lower through hole (1.4.2) are symmetrically arranged about the bottom of the upper through hole (1.4.1).

3. A screen for printing solar cell electrodes according to claim 1 or 2, characterized in that: The plurality of through holes are arranged at equal intervals along the side of the porous membrane (1.4) and horizontally penetrate the porous membrane (1.4); or, the plurality of through holes include a plurality of queues arranged at equal intervals along the side of the porous membrane (1.4), and the through holes in each queue are arranged at equal intervals.

4. The screen for printing solar cell electrodes according to claim 2, characterized in that: The bottom width of the upper through hole (1.4.1) is 0.5 to 2.0 mm.

5. The screen for printing solar cell electrodes according to claim 2, characterized in that: The angle between the side and the bottom of the lower through hole (1.4.2) is 45-75 degrees.

6. The screen for printing solar cell electrodes according to claim 3, characterized in that: The distance between adjacent queues is not less than the bottom width of the lower through hole (1.4.2).

7. The screen for printing solar cell electrodes according to claim 1, characterized in that: The thickness of the porous membrane (1.4) is greater than the thickness of the mesh plate (1.3).

8. A screen for printing solar cell electrodes according to claim 1 or 4, characterized in that: The mesh plate (1.3) is composed of square grids arranged at equal intervals, and the grid width is 0.3-0.7 mm.

9. The screen for printing solar cell electrodes according to claim 1, characterized in that: The mesh plate (1.3) is made of stainless steel.

10. The screen for printing solar cell electrodes according to claim 1, characterized in that: Two printing areas (1) are arranged in parallel in the outer frame (8), and a gap is left between the two printing areas (1).

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