Filament plate for solar cell grid line printing and printing equipment

Abstract

The utility model relates to the technical field of solar cell manufacturing, and particularly discloses a filament plate for solar cell grid line printing and printing equipment. The filament plate for solar cell grid line printing comprises an installation frame and a plurality of filaments. The plurality of filaments are sequentially arranged along the transverse direction or the longitudinal direction, and the diameter of each filament is smaller than or equal to 22 microns, so that each filament can print the metal slurry dipped on the surface of the filament on the surface of a battery silicon wafer to form a grid line with the width within 22 microns; the mounting frame comprises a first fixing plate and a second fixing plate; and the two end parts of the filament are fixedly mounted on the first fixing plate and the second fixing plate respectively. The filament plate for printing the solar cell grid line can reduce the number of filaments, simplify the structure of the filament plate, reduce the cost, ensure the printing efficiency of the grid line, greatly improve the height-width ratio of the printed grid line, reduce the consumption of metal slurry, and improve the photoelectric conversion efficiency of the cell.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cell manufacturing, in particular to a thin wire plate and printing equipment for printing solar cell grid lines. Background Art

[0002] Generally, the higher the height of the electrode grid line (grid line for short) of a solar cell, the lower the transmission resistance of the grid line; moreover, the grid line will block the light on the surface of the solar cell, so the narrower the width of the grid line, the larger the light receiving area on the surface of the solar cell. Therefore, in order to improve the photoelectric conversion efficiency of the solar cell, it is often necessary to make the grid line on the surface of the solar cell thin and high.

[0003] The prior art, as shown in publication numbers CN208698161U and CN117227314A, usually uses screen printing technology to prepare grid lines on the surface of solar cells: specifically, a scraper or a scraper is used to scrape liquid metal to the hollow area of ​​the screen printing screen, and under the downward pressure of the scraper or the scraper, the liquid metal is squeezed into the hollow area and adheres to the surface of the substrate such as the battery silicon wafer, and then the liquid metal is sintered to form electrode grid lines on the surface of the battery silicon wafer. The hollow area of ​​the mesh cloth of the existing screen printing screen, as shown in CN117227314A, is usually formed by crisscrossing silk threads (such as steel wires) to form a number of mesh holes (also called openings). Therefore, the size of the opening of the screen printing screen determines the width of the grid line.

[0004] At present, the particle size of most of the silver powder and glass powder in the liquid metal (also called metal paste, such as silver paste) used to make the electrode grid lines of solar cells can reach more than 6μm, and the silver paste itself has agglomeration phenomenon, which is more obvious under the action of a scraper or a scraper; therefore, in order to ensure the ink permeability of the opening of the screen printing screen to prevent the opening from being blocked by the silver paste, it is difficult to make the opening of the screen printing screen smaller to meet the needs of narrow line width grid lines. Moreover, during the screen printing process, the downward pressure of the scraper or scraper easily causes the mesh of the screen printing screen to contact the surface of the substrate such as the battery silicon wafer, which is also difficult to meet the higher height requirements of the grid line, resulting in the grid line being easily broken. Furthermore, it is difficult to ensure that the grid line has a better aspect ratio using the existing screen printing screen. In addition, the production of the screen printing screen requires a large number of cross-threaded silk threads, which also leads to high production costs of the screen printing screen, which in turn affects the production cost of the grid line. Utility Model Content

[0005] The utility model aims to overcome the shortcomings of the prior art and provide a thin wire plate and printing equipment for printing solar cell grid lines.

[0006] Based on this, the utility model discloses a thin wire plate for printing solar cell grid lines, including a mounting frame and a plurality of thin wires;

[0007] The plurality of filaments are arranged in sequence in the transverse or longitudinal direction, and the diameter of the filaments is less than or equal to 22 μm, so that each filament can print the metal paste dipped on its surface on the surface of the battery silicon wafer to form a gate line with a width of less than 22 μm;

[0008] The mounting frame comprises a first fixing plate and a second fixing plate; two ends of the filament are fixedly mounted on the first fixing plate and the second fixing plate respectively.

[0009] Preferably, the diameter of the filament is 5-20 μm.

[0010] Further preferably, the filament is a high-strength tungsten steel wire, stainless steel wire or carbon fiber wire, and the yield strength of the filament is 1000-10000 MPa;

[0011] The number of the filaments is consistent with the number of gate lines required on the surface of the battery silicon wafer.

[0012] Preferably, the first fixing plate and the second fixing plate each include a fixing sheet for fixing the end of the filament and a mounting plate for inserting the fixing sheet; a mounting groove with an upward opening is provided in the mounting plate for inserting the fixing sheet; a clamping groove for clamping the filament and communicating with the mounting groove is provided on one side of the mounting plate close to the filament;

[0013] The number of the slots is consistent with the number of the filaments, and the slots are arranged on the surface of the mounting plate at intervals.

[0014] Further preferably, a fastener for fastening the fixing plate is provided on a side of the first fixing plate and / or the second fixing plate away from the filament;

[0015] The fastener is a threaded fastener, one end of which is screwed into the mounting plate and contacts a side of the fixing plate away from the filament, so as to press the fixing plate between the inner side wall of the mounting groove and the threaded fastener.

[0016] Preferably, the mounting frame further comprises a mounting bracket for mounting the filament plate on an external printing device, and one end of the first fixing plate and the second fixing plate are both connected to the mounting bracket.

[0017] The utility model also discloses a solar cell grid line printing device, comprising a rotating worktable and a filament plate installed above the rotating worktable; the rotating worktable surface is provided with a slurry tank for loading metal slurry and a station for placing battery silicon wafers; the filament plate is a filament plate for printing solar cell grid lines described above in the utility model;

[0018] The side of the rotating workbench is equipped with a lifting device, a positioning device for positioning the battery silicon wafer on the rotating workbench surface, and a plane offset device for driving the filament plate to offset along the plane to align with the surface of the battery silicon wafer on the rotating workbench; the filament plate is installed on the side of the lifting device close to the rotating workbench, so that the lifting device drives the filament plate to move up and down.

[0019] Preferably, the slurry tank includes a slurry plate, which is provided with a plurality of strip grooves arranged in sequence along the horizontal or vertical direction; the number of the strip grooves is consistent with the number of filaments in the filament plate, so that each filament can be immersed in the corresponding strip groove to dip the metal slurry.

[0020] Preferably, the lifting device comprises a lifting drive member, a lifting rod and a lifting platform, and the lower end and the upper end of the lifting rod are respectively connected to the lifting drive member and the lifting platform;

[0021] The plane offset device is installed on the lifting platform, and one side of the plane offset device is connected to the filament plate, so that the plane offset device drives the filament plate to move along the X-axis and Y-axis directions of the plane, and drives the filament plate to rotate along the plane.

[0022] Further preferably, the plane offset device comprises an offset driving member, a rotating member, an arc guide rail, two screw rods and an X-axis moving member;

[0023] The offset driving member is installed on the lifting platform, and the two ends of the driving rod of the offset driving member are respectively connected to one end of the two screw rods, and the other ends of the two screw rods are connected to the filament plate, so that the offset driving member drives the two screw rods to move along the Y axis through the driving rod, thereby driving the filament plate to move along the Y axis;

[0024] One end of the rotating member is connected to the driving rod of the offset driving member, and the other end of the rotating member is located on the arc guide rail. The offset driving member drives the rotating member to rotate along the arc guide rail, so that the rotating member drives the two lead screws to rotate through the driving rod, thereby driving the filament plate to rotate;

[0025] The two ends of the X-axis moving member are respectively connected to two screw rods, and the X-axis moving member drives the two screw rods to move along the X-axis, so that the two screw rods drive the filament plate to move along the X-axis.

[0026] Preferably, the solar cell grid line printing device of the utility model further comprises a conveyor belt installed on the side of the rotating worktable and used for conveying the cell silicon wafers.

[0027] Compared with the prior art, the utility model has at least the following beneficial effects:

[0028] The utility model of the thin wire plate for printing grid lines of solar cells can save at least half of the investment of thin wires, greatly reduce the raw material cost of the thin wire plate, and the thin wire plate has a simple structure and low production cost, thereby reducing the production cost of the grid lines. The thin wire plate can directly print the metal slurry dipped on the surface of a plurality of thin wires on the surface of the battery silicon wafer, and one thin wire is correspondingly printed for one grid line, so that a plurality of corresponding grid lines can be formed on the surface of the battery silicon wafer synchronously, and the printing efficiency of the grid lines can be ensured; and then through the cooperation of thin wires with smaller diameters, narrower grid lines can be obtained, which effectively reduces the light blocking of the solar cell surface by the grid lines, and can obtain higher grid lines by overprinting the thin wire plates; in this way, the aspect ratio of the printed grid lines can be greatly improved (the width of the grid lines can be controlled within 22μm, and the aspect ratio of the grid lines is above 50%), so as to further improve the photoelectric conversion efficiency of the solar cell.

[0029] The solar cell grid line printing device of the utility model can print metal paste on the surface of the cell silicon wafer with high accuracy through the cooperation of a rotating workbench, a filament plate, a lifting device, a positioning device and a plane offset device to prevent the grid line from being printed off-center. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a schematic diagram of the structure of a solar cell grid line printing device according to the embodiment.

[0031] Figure 2 for Figure 1 Schematic diagram of the enlarged structure of the slurry tank.

[0032] Figure 3 It is a schematic structural diagram of another perspective of a solar cell grid line printing device of this embodiment.

[0033] Figure 4 It is a schematic structural diagram of a thin wire plate for printing solar cell grid lines according to the present embodiment.

[0034] Figure 5 It is a schematic diagram of the partial decomposition structure of a filament plate for printing solar cell grid lines according to this embodiment.

[0035] Figure 6 for Figure 5 Schematic diagram of the enlarged structure of the mounting plate in.

[0036] Figure 7 It is a partial structural schematic diagram of another viewing angle of a thin wire plate for printing grid lines of a solar cell according to the present embodiment.

[0037] Figure 8 It is a schematic diagram of the cross-sectional structure of the battery silicon wafer after obtaining the metal paste printed for the first time according to the printing method of this embodiment.

[0038] Fig. 9 This is a schematic diagram of the cross-sectional structure of a cell silicon wafer after obtaining the metal paste dried for the first time according to the printing method of this embodiment.

[0039] Fig.10 It is a schematic diagram of the cross-sectional structure of the battery silicon wafer after obtaining the metal paste printed for the second time according to the printing method of this embodiment.

[0040] Fig.11 This is a schematic diagram of the cross-sectional structure of a cell silicon wafer after obtaining the metal paste dried for the second time according to the printing method of this embodiment.

[0041] Fig.12 It is a schematic diagram of the cross-sectional structure of the battery silicon wafer after sintering to form the gate lines by the printing method of this embodiment.

[0042] Explanation of the accompanying drawings: filament version 10; filament 11; mounting frame 12; first fixing plate 121; second fixing plate 122; fixing sheet 123; mounting plate 124; mounting groove 1241; slot 1242; fastener 1243; mounting bracket 125; connecting plate 126; rotating worktable 20; slurry groove 21; slurry plate 211; strip groove 2111; workstation 22; lifting device 30; lifting drive member 31; lifting rod 32; lifting platform 33; positioning device 40; plane offset device 50; offset drive member 51; rotating member 52; arc guide rail 53; screw rod 54; X-axis moving member 55; conveyor belt 60; battery silicon wafer 70; metal slurry printed for the first time 71; metal slurry dried for the first time 72; metal slurry printed for the second time 73; metal slurry dried for the second time 74; grid line 75. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0044] Example

[0045] A solar cell grid line printing device of this embodiment, see Figure 1-3 , including a rotating workbench 20, a filament plate 10 and a conveyor belt 60. The filament plate 10 is used to print the metal paste dipped on its surface directly on the surface of the battery silicon wafer 70, and then form a grid line 75 (such as a silver paste) on the surface of the battery silicon wafer 70 for conducting current by sintering the metal paste (such as silver paste). Fig.12 shown).

[0046] The filament plate 10 is installed above the rotating table 20. The rotating table 20 is provided with a slurry tank 21 for loading metal slurry and a station 22 for placing the battery silicon wafer 70. The rotating table 20 rotates itself to make the slurry tank 21 and the station 22 rotate alternately to the bottom of the filament plate 10, so as to respectively realize the following two working processes: the filament plate 10 dips the metal slurry in the slurry tank 21 and the filament plate 10 directly prints the metal slurry dipped on its surface on the surface of the battery silicon wafer 70.

[0047] In order to improve the printing efficiency of the metal paste required to form the gate line, Figure 1-3 As shown, two or more slurry tanks 21 can be arranged on the surface of the rotating worktable 20, and two or more workstations 22 can also be arranged on the surface of the rotating worktable 20, and the slurry tanks 21 and the workstations 22 are arranged alternately.

[0048] Specifically, see Figure 3 The slurry tank 21 includes a slurry plate 211, and the slurry plate 211 is provided with a plurality of strip grooves 2111; these plurality of strip grooves 2111 are arranged in sequence in the horizontal direction or in the vertical direction on the slurry plate 211. The strip grooves 2111 are filled with metal slurry, and the number of the strip grooves 2111 is consistent with the number of filaments 11 of the filament plate 10, so that each filament 11 of the filament plate 10 can be immersed in the corresponding strip groove 2111 to dip in the metal slurry. A plurality of strip grooves 2111 are arranged on the slurry plate 211, and the amount of metal slurry contained in each strip groove 2111 is small, so that the fluctuation of the metal slurry in the strip groove 2111 caused by the rotation of the rotary worktable 20 can be effectively reduced, so as to avoid unnecessary waste caused by splashing of the metal slurry, and make the loading of the metal slurry more stable.

[0049] The conveyor belt 60 is installed on the side of the rotating table 20. Before printing the gate lines, the cell silicon wafer 70 can be transported to the station 22 of the rotating table 20 by the conveyor belt 60; and after printing the gate lines, the cell silicon wafer 70 can be sent away from the rotating table 20 by the conveyor belt 60 to complete the subsequent process (such as the drying process).

[0050] The side of the rotating table 20 is also equipped with a lifting device 30, a positioning device 40 for positioning the battery silicon wafer 70 on the surface of the rotating table 20, and a positioning device 40 for driving the filament plate 10 along a plane (such as Figure 1 The plane offset device 50 is used to offset the surface of the cell silicon wafer 70 aligned with the rotating table 20. The filament plate 10 is installed on the side of the lifting device 30 close to the rotating table 20 so that the lifting device 30 can drive the filament plate 10 along the rotating table 20. Figure 1 The Z-axis direction shown is for up and down movement.

[0051] In practice, the positioning device 40 is preferably a camera positioning device 40; the camera positioning device 40, the lifting device 30 and the plane offset device 50 are all equipped with controllers. The camera is installed above the rotating table 20. The camera is used to collect the position information of the battery silicon wafer 70 on the workstation 22 of the rotating table 20, and the camera positioning device 40 transmits the collected position information to the lifting device 30 and the plane offset device 50; according to the position information, the lifting device 30 moves downward to drive the filament plate 10 to move downward to the surface close to the battery silicon wafer 70, and the plane offset device 50 is offset along the plane to drive the filament plate 10 to offset along the plane to the position of the required grid line aligned with the surface of the battery silicon wafer 70. In this way, the accuracy of the metal paste printed on the surface of the battery silicon wafer 70 can be ensured to prevent the grid line from being printed off.

[0052] The camera positioning device 40 is preferably a Dahua industrial camera A5201MG50; the lifting device 30 is preferably a brand: OMRON, model: R88M-ZL75030H-BS2; the rotating worktable 20 is preferably FLW003987; the offset drive 51 of the offset device 50 is preferably a printing axis motor of Kronwe: FLW-C12689-01.

[0053] Specifically, the lifting device 30 includes a lifting drive member 31, a lifting rod 32 and a lifting platform 33 (such as Figure 3 As shown), the lower end of the lifting rod 32 is connected to the lifting drive member 31, and the upper end of the lifting rod 32 is connected to the lifting platform 33. Figure 1 The plane offset device 50 is installed on the lifting platform 33, and one side of the plane offset device 50 is connected to the filament plate 10; the plane offset device 50 can drive the filament plate 10 to reciprocate along the X-axis direction and the Y-axis direction of the plane, and the plane offset device 50 can drive the filament plate 10 to rotate along the T-axis direction of the plane.

[0054] In one example of this embodiment, see Figure 3 The plane offset device 50 includes an offset drive member 51, a rotating member 52, an arc-shaped guide rail 53, two screw rods 54 and an X-axis moving member 55. The offset drive member 51 is installed on the surface of the lifting platform 33, and the two ends of the driving rod of the offset drive member 51 are respectively connected to one end of the two screw rods 54, and the other ends of the two screw rods 54 are connected to the filament plate 10; in this way, the offset drive member 51 can drive the two screw rods 54 to reciprocate along the Y-axis through the driving rod, so that the two screw rods 54 can drive the filament plate 10 to reciprocate along the Y-axis. One end of the rotating member 52 is connected to the driving rod of the offset drive member 51, and the other end of the rotating member 52 is located on the arc-shaped guide rail 53; in this way, the offset drive member 51 drives the rotating member 52 to rotate along the arc-shaped guide rail 53 (such as Figure 1The two ends of the X-axis moving member 55 are respectively connected to the middle of the two screw rods 54, and the X-axis moving member 55 drives the two screw rods 54 to reciprocate along the X-axis direction, so that the two screw rods 54 drive the filament plate 10 to reciprocate along the X-axis direction.

[0055] Among them, see Figure 4-7 The thin wire plate 10 is a thin wire plate 10 for printing solar cell grid lines as described below in this embodiment:

[0056] A filament plate 10 for printing solar cell grid lines of the present embodiment includes a mounting frame 12 and a plurality of filaments 11. Among them, the plurality of filaments 11 are arranged in sequence along the horizontal direction (in this case, the filament plate 10 does not contain a plurality of filaments 11 arranged along the vertical direction); or the plurality of filaments 11 are arranged in sequence along the vertical direction (in this case, the filament plate 10 does not contain a plurality of filaments 11 arranged along the horizontal direction). In this way, compared with the existing screen printing screen, the filament plate 10 of the present embodiment can save at least more than half of the investment in filaments 11, which can greatly reduce the raw material cost of the filament plate 10. The filament plate 10 has a simple structure and low production cost, which can further reduce the production cost of the grid lines.

[0057] Furthermore, the diameter of the filament 11 is less than or equal to 22 μm, so that each filament 11 can directly print the metal paste dipped on its surface on the surface of the battery silicon wafer 70, so as to form a grid line with a width of less than 22 μm on the surface of the battery silicon wafer 70. Specifically, the diameter of the filament 11 is preferably 5-20 μm (such as 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm or 20 μm). The number of filaments 11 is consistent with the number of grid lines required on the surface of the battery silicon wafer 70, that is, each filament 11 is printed with one grid line. The filament plate 10 does not print the metal paste through openings or meshes, so there is no need to consider the ink permeability of the openings of the existing screen printing screen. The filament plate 10 uses filaments 11 with smaller diameters to obtain grid lines with narrower widths, so as to effectively reduce the light blocking of the solar cell surface by the grid lines. Moreover, the plurality of filaments 11 of the filament plate 10 can simultaneously print a plurality of corresponding gate lines on the surface of the battery silicon wafer 70 to ensure the printing efficiency of the gate lines.

[0058] The filament 11 is a high-strength, corrosion-resistant and uniformly sized tungsten steel wire, stainless steel wire or carbon fiber wire; the yield strength of the filament 11 is 1000-10000MPa (such as 1000MPa, 5000MPa, 8000MPa or 10000MPa). The use of high-strength, uniformly sized filaments 11, on the one hand, prevents the filaments 11 from bending and deforming during the printing process, and can strictly control the size of the printed grid lines, improve the accuracy and quality of the grid line printing, and on the other hand, prevents the filaments 11 from breaking due to their small diameter, which affects the printing of the grid lines. Moreover, the filaments 11 are corrosion-resistant and can increase the service life of the filament plate 10.

[0059] The mounting frame 12 includes a first fixing plate 121, a second fixing plate 122, a mounting bracket 125 and a connecting plate 126. The mounting bracket 125 is used to mount the filament plate 10 on the plane offset device 50 of the solar cell grid line printing device described above in this embodiment, so that the filament plate 10 is connected to the two screw rods 54 of the plane offset device 50 through the mounting bracket 125. One end of the first fixing plate 121 and the second fixing plate 122 are connected to the mounting bracket 125, and the other end of the first fixing plate 121 and the second fixing plate 122 are connected to the connecting plate 126. In this way, the first fixing plate 121, the connecting plate 126, the second fixing plate 122 and the mounting bracket 125 are connected in sequence to form a square mounting frame 12 to ensure the structural stability of the mounting frame 12.

[0060] Furthermore, one end of the plurality of filaments 11 is fixedly mounted on the first fixing plate 121 , and the other end of the plurality of filaments 11 is fixedly mounted on the second fixing plate 122 , so that a filament plate 10 with a simple structure and a stable overall structure can be obtained.

[0061] In practice, the end of the filament 11 may be fixedly mounted by laser spot welding, glue bonding or other fixing methods.

[0062] To ensure that the filament 11 is not broken due to excessive stretching of the first fixing plate 121 and the second fixing plate 122, the distance between the first fixing plate 121 and the second fixing plate 122 can be slightly smaller than the length of the filament 11. For example, the distance between the first fixing plate 121 and the second fixing plate 122 is 0-3 mm (such as 0.05 mm, 0.5 mm, 1 mm, 2 mm or 3 mm) smaller than the length of the filament 11.

[0063] Specifically, see Figure 5-7 The first fixing plate 121 and the second fixing plate 122 each include a fixing sheet 123 for fixing the end of the filament 11 and a mounting plate 124 for inserting and installing the fixing sheet 123. The mounting plate 124 is provided with a mounting groove 1241 (such as Figure 6Further, a side of the mounting plate 124 close to the filament 11 is provided with a slot 1242 (as shown in FIG. Figure 6 As shown in the figure, the card slot 1242 is connected to the installation slot 1241. Moreover, the number of the card slots 1242 is consistent with the number of the filaments 11, and each card slot 1242 is arranged on the surface of the installation plate 124 at intervals. Therefore, when the fixing plate 123 is inserted into the installation slot 1241, the filament 11 can also be snapped into the card slot 1242; in this way, the structural design of the filament board 10 is reasonable, the installation process is simple, and the filament 11 is snapped into the card slot 1242, which can also fix and position the filament 11, so as to prevent the filament 11 from shaking and causing the grid line to be printed off, so as to improve the accuracy and quality of the grid line printing.

[0064] Further, a fastener 1243 for fastening the fixing plate 123 is provided on one side of the first fixing plate 121 and / or the second fixing plate 122 away from the filament 11. Specifically, the fastener 1243 is preferably a threaded fastener, and one end of the threaded fastener is screwed into the mounting groove 1241 of the mounting plate 124, so that the end of the threaded fastener contacts the side of the fixing plate 123 away from the filament 11, and then the fixing plate 123 is pressed between the inner side wall of the mounting groove 1241 and the threaded fastener. In this way, the distance between the two fixing plates 123 can be controlled by fastening the two fixing plates 123, and then the spacing between the two ends of the filament 11 can be strictly controlled to avoid the filament 11 shaking or unnecessary movement to affect the accuracy of the grid line printing, so the quality of the printed grid line can be further improved; moreover, the spacing between the two ends of the filament 11 can also be strictly controlled to avoid the filament 11 from being overstretched and causing breakage, thereby improving the structural stability and service life of the filament version 10.

[0065] In summary, the filament plate 10 of the present embodiment prints the metal paste dipped on its surface directly onto the surface of the battery silicon wafer 70; unlike the existing screen printing screen, there is no need to use a scraper or a scraper to scrape the metal paste into the opening, and then use the downward pressure of the scraper or the scraper to print the metal paste in the opening onto the surface of the battery silicon wafer.

[0066] Therefore, compared with the existing silk screen printing screen, the filament plate 10 does not print the metal paste through openings or meshes, and naturally there is no need to consider the ink permeability of the openings of the existing silk screen printing screen. The filament plate 10 uses filaments 11 with smaller diameters to greatly reduce the width of the printed metal paste, thereby obtaining a narrower grid line, so as to effectively reduce the grid line from blocking the light on the surface of the solar cell.

[0067] Moreover, compared with the existing silk screen printing screen, the fine wire plate 10 can complete the printing of metal paste without the aid of a scraper or a scraper, so there will be no scraper or a scraper pressing down to cause the mesh of the silk screen to contact the surface of the battery silicon wafer. Therefore, the fine wire plate 10 can be used to print metal paste with a larger height, thereby obtaining a grid line with a larger height.

[0068] Therefore, the filament board 10 of this embodiment can also greatly improve the aspect ratio of the printed grid lines, so as to further improve the photoelectric conversion efficiency of the solar cell. The test found that the width of the grid lines printed by the filament board 10 of this embodiment can be controlled within 22 μm, and the aspect ratio of the grid lines is above 50%.

[0069] A method for printing a solar cell grid line in this embodiment, see Figure 1-3 , which uses the solar cell grid line printing equipment described above in this embodiment to complete the printing of metal paste on the surface of the cell silicon wafer 70. This printing method, see Figure 8-12 , which includes the following printing steps:

[0070] Step 1: The rotating workbench 20 rotates to drive the slurry tank 21 to rotate to the bottom of the filament plate 10.

[0071] Step 2, the lifting device 30 drives the filament plate 10 to move downward so that a plurality of filaments 11 are dipped into the metal slurry (such as silver slurry) for making the grid lines 75 in the slurry tank 21, and then the lifting device 30 drives the filament plate 10 to move upward.

[0072] Step 3: The rotating workbench 20 rotates to drive the battery silicon wafer 70 at the workstation 22 to rotate to the bottom of the filament plate 10.

[0073] In practice, before step 3, the conveyor belt 60 can be used to transport the battery silicon wafer 70 to the station 22. After the station 22 rotates to the corresponding position of the conveyor belt 60, the encoder under the rotating workbench 20 (specifically started at the corresponding position of the conveyor belt 60) senses the rotation angle, and the motor under the station 22 rotates the table paper on the station 22 to transport the battery silicon wafer 70 to the middle position of the station 22. During the rotation process, there is always vacuum adsorption to ensure that the battery silicon wafer 70 will not deviate. The left and right ends of the table paper on the station 22 are fixed by a hollow tube (such as a PVC tube), and the two ends of the hollow tube are inserted into the two screws of the motor under the station 22 for fixing, so that the motor can drive the hollow tube to rotate through the two screws, so that the forward and backward displacement of the table paper above the station 22 can be realized. The encoder under the rotating workbench 20, the motor under the station 22, the table paper on the station 22, and the fixing structure of the table paper are all prior art, so they are not expanded in detail.

[0074] Step 4: The positioning device 40 collects the position information of the battery silicon wafer 70 at the workstation 22 , and the plane offset device 50 drives the filament plate 10 to offset along the plane according to the position information to align with the surface of the battery silicon wafer 70 on the rotating worktable 20 .

[0075] Step 5: The lifting device 30 drives the filament plate 10 to move downward to make the plurality of filaments 11 contact the surface of the battery silicon wafer 70, so as to directly print the metal paste on the lower surface of the plurality of filaments 11 on the surface of the battery silicon wafer 70, so as to form a plurality of first printed metal pastes 71 (such as Figure 8 shown).

[0076] Step 6: The lifting device 30 drives the filament plate 10 to move upward, and the rotating workbench 20 rotates to transfer the cell silicon wafer 70 to the conveyor belt 60. The table paper on the workstation 22 rotates to transfer the cell silicon wafer 70 from the workstation 22 table to the conveyor belt. The cell silicon wafer 70 is transported away by the conveyor belt 60 and then enters a drying device (such as an oven) to dry the first printed metal paste 71 on the surface of the cell silicon wafer 70 to form a first dried metal paste 72 (such as Fig. 9 As shown), thus, one printing of the metal paste is completed.

[0077] Step 7: Use the conveyor belt 60 to convey the cell silicon wafer 70 with the metal paste 72 dried for the first time to the workstation 22, and repeat steps 1-6 to continue to overprint the metal paste 73 printed for the second time (such as Fig.10 ), and then drying the second printed metal paste 73 to form a second dried metal paste 74 (as shown in FIG. Fig.11 As shown), in this way, the metal paste on the surface of the battery silicon wafer 70 is piled up. The number of times the metal paste is printed on the surface of the battery silicon wafer 70 is preferably 2-5 times, and multiple overprinting can also effectively prevent the problem of broken grid.

[0078] Step 8: Finally, a subsequent metal slurry sintering process is performed to form a gate line 75 (eg, Fig.12 shown).

[0079] The above-mentioned printing method of this embodiment does not have the printing problem caused by the ink permeability of the openings of the existing screen printing screen, and has a lower requirement for the viscosity of the metal slurry; it only needs to ensure that the metal slurry itself has a certain viscosity characteristic, and the filament 11 will not fall off during the lifting process, thereby ensuring the straightness of the grid line 75. Moreover, the width of the grid line 75 printed by the printing method mainly depends on the diameter size of the filament 11, and there is basically no widening effect.

[0080] During the printing process, the height of the metal paste printed each time is preferably 2-5μm (such as 2μm, 3μm or 5μm), that is, the height of the metal paste 71 printed for the first time is controlled at 2-5μm, and the height of the metal paste 73 printed for the second time is also controlled at 2-5μm; this can not only effectively prevent gate breakage, but also save metal paste, reduce metal paste consumption, and reduce the cost of gate line 75.

[0081] The process is carried out by drying in an oven, and the oven temperature is controlled at 100-400°C (such as 180°C, 200°C or 300°C); after the first drying, the metal paste 72 of the first drying is formed; the thin wire 11 is repeatedly dipped in the metal paste to continue to be overprinted on the metal paste 72 of the first drying to a certain height, and the above operation is repeated 2-5 times, and finally sintered to form the gate line 75, so that the gate line 75 forms an ohmic contact with the battery silicon wafer 70, and a thin and high gate line 75 can be obtained. Therefore, the printing method of this embodiment can realize the printing of the gate line 75 with a narrower line width, obtain the gate line 75 with a better aspect ratio (the width of the gate line 75 can be controlled within 22μm, and the aspect ratio of the gate line 75 is above 50%), reduce the silver paste consumption of the solar cell grid line 75, and improve the photoelectric conversion efficiency of the battery, and ensure the efficiency and accuracy of the printing of the grid line 75. Moreover, the cost of the thin wire version 10 is lower than that of the existing screen printing screen.

[0082] Although the preferred embodiments of the utility model embodiments have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the utility model embodiments.

[0083] The technical solution provided by the utility model is introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation mode of the utility model. The description of the above embodiments is only used to help understand the method and core idea of ​​the utility model. At the same time, for general technicians in this field, according to the idea of ​​the utility model, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as a limitation on the utility model.

Claims

1. A thin wire plate for printing solar cell grid lines, characterized in that: It includes a mounting frame and a number of filaments; The plurality of filaments are arranged in sequence in the transverse or longitudinal direction, and the diameter of the filaments is less than or equal to 22 μm, so that each filament can print the metal paste dipped on its surface on the surface of the battery silicon wafer to form a gate line with a width of less than 22 μm; The mounting frame comprises a first fixing plate and a second fixing plate; two ends of the filament are fixedly mounted on the first fixing plate and the second fixing plate respectively.

2. The thin wire plate for printing solar cell grid lines according to claim 1, characterized in that: The diameter of the filaments is 5-20 μm.

3. A thin wire plate for printing solar cell grid lines according to claim 1 or 2, characterized in that: The filaments are tungsten steel wires, stainless steel wires or carbon fiber wires; the number of the filaments is consistent with the number of grid lines required on the surface of the battery silicon wafer.

4. The thin wire plate for printing solar cell grid lines according to claim 1, characterized in that: The first fixing plate and the second fixing plate each include a fixing plate for fixing the end of the filament and a mounting plate for inserting the fixing plate; a mounting groove with an upward opening is provided in the mounting plate for inserting the fixing plate; a clamping groove for clamping the filament and communicating with the mounting groove is provided on one side of the mounting plate close to the filament; The number of the slots is consistent with the number of the filaments, and the slots are arranged on the surface of the mounting plate at intervals.

5. The thin wire plate for printing solar cell grid lines according to claim 4, characterized in that: A fastener for fastening the fixing plate is provided on a side of the first fixing plate and / or the second fixing plate away from the filament; The fastener is a threaded fastener, one end of which is screwed into the mounting plate and contacts a side of the fixing plate away from the filament, so as to press the fixing plate between the inner side wall of the mounting groove and the threaded fastener.

6. The thin wire plate for printing solar cell grid lines according to claim 1, characterized in that: The mounting frame also includes a mounting bracket for mounting the filament plate on an external printing device, and one end of the first fixing plate and the second fixing plate are both connected to the mounting bracket.

7. A solar cell grid line printing device, characterized in that: It comprises a rotating worktable and a filament plate installed above the rotating worktable; the rotating worktable surface is provided with a slurry tank for loading metal slurry and a station for placing battery silicon wafers; the filament plate is a filament plate for printing solar cell grid lines according to any one of claims 1 to 6; The side of the rotating workbench is equipped with a lifting device, a positioning device for positioning the battery silicon wafer on the rotating workbench surface, and a plane offset device for driving the filament plate to offset along the plane to align with the surface of the battery silicon wafer on the rotating workbench; the filament plate is installed on the side of the lifting device close to the rotating workbench, so that the lifting device drives the filament plate to move up and down.

8. The solar cell grid line printing device according to claim 7, characterized in that: The slurry tank includes a slurry plate, which is provided with a plurality of strip grooves arranged in sequence along the horizontal or vertical direction; the number of the strip grooves is consistent with the number of filaments on the filament plate, so that each filament can be immersed in the corresponding strip groove to dip the metal slurry.

9. The solar cell grid line printing device according to claim 7, characterized in that: The lifting device comprises a lifting drive member, a lifting rod and a lifting platform, wherein the lower end and the upper end of the lifting rod are respectively connected to the lifting drive member and the lifting platform; The plane offset device is installed on the lifting platform, and one side of the plane offset device is connected to the filament plate, so that the plane offset device drives the filament plate to move along the X-axis and Y-axis directions of the plane, and drives the filament plate to rotate along the plane.

10. The solar cell grid line printing device according to claim 9, characterized in that: The plane offset device includes an offset driving member, a rotating member, an arc guide rail, two lead screws and an X-axis moving member; The offset driving member is installed on the lifting platform, and the two ends of the driving rod of the offset driving member are respectively connected to one end of the two screw rods, and the other ends of the two screw rods are connected to the filament plate, so that the offset driving member drives the two screw rods to move along the Y axis through the driving rod, thereby driving the filament plate to move along the Y axis; One end of the rotating member is connected to the driving rod of the offset driving member, and the other end of the rotating member is located on the arc guide rail. The offset driving member drives the rotating member to rotate along the arc guide rail, so that the rotating member drives the two lead screws to rotate through the driving rod, thereby driving the filament plate to rotate; The two ends of the X-axis moving member are respectively connected to two screw rods, and the X-axis moving member drives the two screw rods to move along the X-axis, so that the two screw rods drive the filament plate to move along the X-axis.

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