Grid line forming device, forming method and screen printing equipment

Abstract

The invention provides a grid line forming device, a grid line forming method and screen printing equipment, relates to the technical field of photovoltaics, and aims to solve the technical problem that the height-width ratio of a grid line of a photovoltaic cell is difficult to increase in a screen printing process. The grid line forming device comprises a first linear motion mechanism, a frame structure and at least one group of silk threads, wherein the frame structure comprises two opposite frames; each group of silk threads comprises two silk threads, two ends of each silk thread are respectively arranged on the two frames in a sliding manner, and the two silk threads in the same group of silk threads move in opposite directions; the frame structure is connected with the first linear motion mechanism, and the motion direction of the first linear motion mechanism is perpendicular to the plane where at least one set of silk threads are located. The grid line forming device is used for regulating and controlling the shape of the grid line of the photovoltaic battery piece, the height-width ratio of the grid line can be improved, the influence of the front grid line of the photovoltaic battery piece on light absorption is reduced, the line resistance is reduced, and the performance of the photovoltaic battery piece is optimized.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a grid line forming device, a forming method and a screen printing device. Background Art

[0002] The statements in this section merely provide background art related to the present invention and do not necessarily constitute prior art.

[0003] For the grid lines (electrodes) on the light-receiving surface of the photovoltaic cell, it is necessary to reduce the line resistance of the grid lines while ensuring light absorption. Since the front of the photovoltaic cell requires a fixed length of grid lines, in order not to reduce the conductivity of the grid lines, it is necessary to increase the height of the grid lines and reduce the width, that is, increase the height-to-width ratio of the grid lines, so as to reduce the shading effect while maintaining or reducing the line resistance of the grid lines.

[0004] Photovoltaic cells usually use screen printing to prepare grid lines on the surface. Through a screen with a specific ink-permeable pattern, the slurry that forms the grid lines leaks ink in the hollows of the ink-permeable pattern, and the required grid line pattern is obtained on the substrate of the photovoltaic cell. However, in order to obtain grid lines with a large aspect ratio, the screen printing screen will reduce the life of the screen and may cause poor grid line patterns. Summary of the invention

[0005] The object of the present invention is to provide a grid line forming device, a forming method and a screen printing device to solve the technical problem that it is difficult to increase the aspect ratio of the grid line of a photovoltaic cell in the screen printing process.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a grid line forming device for adjusting the grid line shape of a photovoltaic cell, the forming device comprising a first linear motion mechanism, a frame structure and at least one group of wires, the frame structure comprising two opposite frames;

[0008] Each group of the silk threads includes two silk threads, and the two ends of each silk thread are slidably arranged on the two frame frames respectively, and the movement directions of the two silk threads in the same group of the silk threads are opposite;

[0009] The frame structure is connected to the first linear motion mechanism, and a motion direction of the first linear motion mechanism is perpendicular to a plane where the at least one group of wires is located.

[0010] According to at least one embodiment of the present invention, the forming device further comprises two first driving mechanisms arranged on the frame, one of the wires in the same group is transmission connected to one of the first driving mechanisms, and the other wire is transmission connected to the other first driving mechanism.

[0011] According to at least one embodiment of the present invention, the wire has a tension greater than a preset tension.

[0012] According to at least one embodiment of the present invention, the material of the wire includes one of polyimide, nylon or alloy steel.

[0013] In a second aspect, the present invention further provides a screen printing device, comprising a screen and the forming device described in the first aspect;

[0014] When the printing device is in a forming mode, the frame structure of the forming device is located in a target area, and the target area refers to the area between the screen and the photovoltaic cell sheet;

[0015] When the printing device is in a printing mode, the frame structure of the forming device is located in other areas except the target area.

[0016] According to at least one embodiment of the present invention, the number of the first linear motion mechanisms is at least one group, each group of the first linear motion mechanisms includes two first linear motion mechanisms, and the two first linear motion mechanisms in the same group are respectively arranged on opposite sides of the screen;

[0017] One end of the first linear motion mechanism is rotatably connected to the screen, and the other end of the first linear motion mechanism is hinged to the frame structure.

[0018] According to at least one embodiment of the present invention, the first linear motion mechanism includes one of a hydraulic cylinder, an electric cylinder or a pneumatic cylinder.

[0019] According to at least one embodiment of the present invention, the screen printing device further comprises an image acquisition device and a control device in communication with the image acquisition device, wherein the image acquisition device is used to acquire position information of the grid lines on the screen;

[0020] The control device is used to control each of the wires of the frame structure to move to the side and below the corresponding grid line based on the position information of the grid line.

[0021] In a third aspect, the present invention further provides a grid line forming method, using the screen printing device described in the second aspect to form the grid line on the photovoltaic cell sheet, the forming method comprising:

[0022] Printing the grid lines on the photovoltaic cell sheet by screen printing;

[0023] Attaching the frame structure to the surface of the photovoltaic cell;

[0024] The frame structure is lifted while two of the wires in the same group of wires are moved toward each other.

[0025] According to at least one embodiment of the present invention, the moving speed of the frame structure away from the photovoltaic cell sheet in a direction perpendicular to the plane where the at least one group of wires is located ranges from 2 μm / s to 5 μm / s; and / or,

[0026] The moving speed of the wire ranges from 1 μm / s to 8 μm / s.

[0027] Among the one or more technical solutions provided in the exemplary embodiments of the present invention, at least one of the following beneficial effects can be achieved.

[0028] The grid line shaping device of the exemplary embodiment of the present invention is used for the shape control of the grid line of screen printing to improve the aspect ratio of the grid line morphology. The grid line shaping device includes a frame structure and at least one group of wires located on the frame structure, each group of wires corresponds to a grid line (paste) screen-printed on a substrate, that is, two wires will shape a corresponding grid line. Specifically, the frame structure is connected to the first linear motion mechanism. Since the movement direction of the first linear motion mechanism is perpendicular to the plane where at least one group of wires is located, the frame structure can be attached to the photovoltaic cell sheet, and the two wires are located at the bottom of the side of the grid line on the surface of the photovoltaic cell sheet. When the frame structure is driven by the first linear motion mechanism and lifted in a direction away from the surface of the photovoltaic cell sheet, the corresponding group of wires located on both sides of the grid line move in a direction close to each other, so that the grid line (paste) is subjected to a pulling effect. Based on this, the slurry width of the grid line printed on the photovoltaic cell sheet can be narrowed while the height is increased, that is, the aspect ratio of the grid line is improved, and the influence of the front grid line on light absorption can be minimized while reducing the line resistance, thereby achieving the purpose of optimizing the performance of the photovoltaic cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings illustrate exemplary embodiments of the present invention and together with the description serve to explain the principles of the present invention, and these drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification;

[0030] Figure 1 is a schematic structural diagram of a molding device according to an embodiment of the present invention;

[0031] Figure 2 is a schematic diagram of the principle of a grid line forming process according to an embodiment of the present invention;

[0032] Figure 3 is a schematic structural diagram of a forming device and a screen according to an embodiment of the present invention;

[0033] Figure 4 is a schematic structural diagram of a first linear motion mechanism according to an embodiment of the present invention;

[0034] Figure 5 A schematic flow chart of the steps of a gate line forming method according to an embodiment of the present invention.

[0035] Figure numerals: 11, frame; 12, wire; 13, slider; 20, screen; 30, photovoltaic cell; 40, grid line; 50, first linear motion mechanism; 51, fixing part; 52, telescopic part. DETAILED DESCRIPTION

[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] The grid lines (electrodes) of photovoltaic cells play a key role in collecting current. For the light-receiving side (front) of the photovoltaic cell, the grid lines need to reduce the line resistance of the grid lines while ensuring light absorption (try not to block light). According to the resistance law formula:

[0038] R l =(ρ*L) / S Formula 1

[0039] Where R l is the line resistance of the gate line itself, in ohms (Ω); ρ—the resistivity of the gate line material, in ohm·meter (Ω·m) in the international system. Generally, the resistivity of a specific gate line material is a fixed value; L—the length of the gate line, in meters (m) in the international system; S—the cross-sectional area of ​​the gate line, in square meters (m 2 ).

[0040] According to Formula 1, when a fixed-length electrode is prepared using a specific grid line material on the front of a photovoltaic cell, in order not to reduce the conductivity of the grid line material, the height of the grid line can only be increased and the width of the grid line can be reduced, that is, the aspect ratio of the grid line can be increased, so as to maintain or reduce the line resistance of the grid line while minimizing light blocking.

[0041] Photovoltaic cells usually use screen printing to prepare grid line electrodes. The screen printing process requires the use of a screen, which has a specific ink-permeable pattern that allows the paste (such as silver paste) that forms the grid line to leak onto the photovoltaic cell at the hollow pattern, thereby forming a grid line pattern on the photovoltaic cell.

[0042] Specifically, the screen is woven by mesh, and a net with different mesh numbers can be obtained, and then an organic film is laid on the net, and the organic film is processed using photosensitive etching to obtain the required grid line pattern. Wherein, the wire diameter of the mesh can affect the size of the mesh number, and the film thickness of the organic film can determine the height of the grid line in the printing process to the greatest extent. If you want to print a higher and narrower electrode, you can only use a screen with fine yarn, high mesh number, and low film thickness. However, this will cause the life of the screen to reduce, thereby increasing the manufacturing cost. In addition, the screen also needs to consider the particle size of the material in the slurry, so as not to cause the mesh to be too small to cause the leakage failure, causing the grid line to be bad.

[0043] In the related art, alloy steel is sometimes used to replace the above-mentioned organic film to prepare the screen, but the steel screen window pattern is not good enough, the hole wall is not smooth, the template size should not be too large, the cost is high, and the production cycle is long.

[0044] In response to the above problems, the grid line forming device of the exemplary embodiment of the present invention can be a simple improvement on the photovoltaic cell screen printing machine. After the screen printing machine forms the grid line pattern on the photovoltaic cell sheet, it moves upward and toward the middle from the bottom on both sides of the grid line through the pulling action of two silk threads, thereby obtaining a higher and narrower grid line morphology, improving the aspect ratio of the grid line, and maximizing the performance of the photovoltaic cell.

[0045] It should be noted that the grid line shaping device can adjust the shape of the thin grid lines on the photovoltaic cell sheet, and can also adjust the shape of the main grid lines on the photovoltaic cell sheet according to actual needs.

[0046] Figure 1 Schematic diagram of the structure of a molding device according to an embodiment of the present invention. Figure 1 As shown, the grid line forming device provided by the exemplary embodiment of the present invention includes a first linear motion mechanism 50, a frame structure and at least one group of wires 12, the frame structure includes two opposite frame frames 11; each group of wires 12 includes two wires 12, the two ends of each wire 12 are respectively slidably arranged on the two opposite frame frames 11, and the movement directions of the two wires 12 in the same group of wires 12 are opposite; the frame structure is connected to the first linear motion mechanism 50, and the movement direction of the first linear motion mechanism 50 is perpendicular to the plane where the at least one group of wires 12 is located, and the grid line forming device is used for shape control of the grid lines 40 screen-printed on the photovoltaic cell 30.

[0047] In practical applications, refer to Figure 2 As shown, Figure 22 is a schematic diagram of the principle of the grid line forming process according to an embodiment of the present invention. After the photovoltaic cell 30 set on the machine table of the screen printer has the grid line pattern printed on its surface through the screen 20, the photovoltaic cell 30 remains stationary on the machine table, and the frame structure is placed on the surface of the photovoltaic cell 30. Since each group of wires 12 of the frame structure corresponds to a grid line 40, there is a wire 12 at the bottom of both sides of each grid line 40, such as Figure 2 The contact pattern in the figure; driven by the first linear motion mechanism 50, the frame structure can move away from the photovoltaic cell 30, that is, the frame structure is lifted. At the same time, the two wires 12 of the same wire 12 move towards each other, that is, relative to the grid line 40, the two wires 12 of the same group of wires 12 are pulled upward and contracted in the middle, as shown in FIG. Figure 2 When the shrinkage and pulling are completed, the grid line 40 on the photovoltaic cell 30 has a higher and narrower appearance and a higher aspect ratio, such as Figure 2 The molding graphics in .

[0048] It should be noted that before placing the frame structure on the surface of the photovoltaic cell 30, the two wires 12 of the same group of wires 12 are first moved away from each other so as to match the bottom width of the grid line 40 to be shaped, and then the frame structure is driven to be placed on the surface of the photovoltaic cell 30 through the descending process of the first linear motion mechanism 50.

[0049] Figure 3 Schematic diagram of the structure of the forming device and the screen according to the embodiment of the present invention. Figure 3 As shown, the molding device provided by the exemplary embodiment of the present invention also includes two first driving mechanisms arranged on the frame 11, one wire 12 in the same group of wires 12 is transmission connected to one first driving mechanism, and the other wire 12 is transmission connected to the other first driving mechanism.

[0050] Exemplarily, two frames 11 on the frame structure have slide rails, and two ends of each wire 12 are respectively provided with sliders 13, and the two ends of each wire 12 are slidably provided on the corresponding slide rails through the corresponding sliders 13. The first driving mechanism can be a motor, a cylinder, a hydraulic cylinder, etc., and the motor is used as an example for explanation. Each wire 12 with the same movement direction is provided with a first synchronous wheel on the first end, and the same motor is used to form a transmission connection with each first synchronous wheel through a synchronous belt. The motor is arranged on one of the two frames 11 (the frame 11 where the first end of each wire 12 is located); another motor is arranged on the other frame 11 (the frame 11 where the second end of each wire 12 is located), and other wires 12 with the same movement direction are provided with a second synchronous wheel on the second end of the other frame 11, and the other motor is used to form a transmission connection with each second synchronous wheel through another synchronous belt. Thus, the movement of two wires 12 of the same group of wires 12 to move closer to or away from each other is achieved by the forward and reverse rotation of the two motors.

[0051] In some embodiments, the material of the wire 12 includes one of polyimide, nylon or alloy steel. The material of the wire 12 can be the same or similar to the material of the organic film on the screen 20 in the screen printer, so that the slurry on the grid line 40 will not be contaminated due to the re-contact process between the wire 12 and the grid line 40.

[0052] In some embodiments, the tension of the wire 12 is greater than the preset tension. The wire 12 has a certain tension that can squeeze the slurry on the gate line 40 , thereby ensuring the shaping of the morphology of the gate line 40 .

[0053] For example, the tension of the wire 12 may be 2N to 4N greater than the tension of the wire of the screen 20 .

[0054] In some embodiments, the distance between two wires 12 of the same group of wires 12 is the actual width of the grid line 40 to be adjusted, and the actual width of the grid line 40 is determined according to the line width of the screen 20 and the widening caused by the ductility of the slurry.

[0055] Figure 4 Schematic diagram of the structure of the first linear motion mechanism according to an embodiment of the present invention. Figure 3 and Figure 4 As shown, an exemplary embodiment of the present invention also provides a screen printing device, including a screen 20 and a molding device of the above-mentioned embodiment; when the printing device is in a molding mode, the frame structure of the molding device is located in a target area, and the target area refers to the area between the screen 20 and the photovoltaic cell 30; when the printing device is in a printing mode, the frame structure of the molding device is located in other areas except the target area.

[0056] In practical applications, the existing screen printing equipment for the grid lines 40 of the photovoltaic cell 30 can be used to shape the grid lines 40 of the photovoltaic cell 30 by simply adding a molding device. This is simple and quick, and a grid line 40 with a higher aspect ratio can be obtained without significantly increasing the cost of use.

[0057] When the printing device is in the printing mode, the screen printing device prints the grid line 40 pattern on the surface of the photovoltaic cell 30 through the screen 20 and the paste.

[0058] When the printing device is in the forming mode, on the basis of the above-mentioned printing mode, the photovoltaic cell 30 does not move temporarily, and remains at the original ink station position, maintaining vacuum suction. The screen 20 rises to form a gap between the photovoltaic cell 30, that is, the target area. Subsequently, the frame structure of the forming device moves to the target area through the motion mechanism, and the two threads 12 in each group of threads move away from each other to match the actual width of the grid line 40 of the photovoltaic cell 30. The frame structure is driven by the first linear motion mechanism 50 to descend to the surface of the photovoltaic cell 30. Next, the frame structure rises under the drive of the first linear motion mechanism 50. At the same time, the two threads 12 in each group of threads 12 move in a direction close to each other, so that the grid line 40 shrinks and pulls upward to the middle. When the frame structure finishes moving, each thread 12 moves away from the grid line 40 of the photovoltaic cell 30, and the frame structure begins to return to its original position, completing a cycle of the printing mode-circulation mode.

[0059] There are various ways to switch the frame structure of the forming device between the target area and other areas outside the target area.

[0060] For example, a second linear motion mechanism is provided on the screen printing machine to accurately enable the frame structure to enter and exit the target area. The second linear motion mechanism can be a hydraulic cylinder, an electric cylinder, or a cylinder. The second linear motion mechanism is described below as an example of a second cylinder. The first linear motion mechanism 50 can also be a hydraulic cylinder, an electric cylinder, or a cylinder. The first linear motion mechanism 50 is described below as an example of a first cylinder.

[0061] Exemplarily, the cylinder barrel of the second cylinder is fixedly arranged on the machine platform where the photovoltaic cell 30 is placed, for example, located behind the photovoltaic cell 30, the telescopic portion 52 of the second cylinder is fixedly connected to the cylinder barrel of the first cylinder, the movement direction of the telescopic portion 52 of the second cylinder is parallel to the direction of the photovoltaic cell 30, and the telescopic portion 52 of the second cylinder is located between the screen 20 and the photovoltaic cell 30 in the vertical direction. The telescopic portion 52 of the first cylinder is fixedly connected to the frame structure.

[0062] When the screen printing device is in the printing mode, the telescopic part 52 of the second cylinder retracts, and the frame structure is driven to move out of the target area through the first cylinder; when the screen printing device prints the grid line 40 pattern on the surface of the photovoltaic cell 30 through the screen 20 and the slurry, the telescopic part 52 of the second cylinder extends, and the frame structure is driven to enter the target area through the first cylinder, and the telescopic part 52 of the first cylinder is extended, so that the frame structure fits on the surface of the photovoltaic cell 30, and the two wires 12 of the same group are respectively located on the side and below the corresponding grid line 40; the telescopic part 52 of the first cylinder retracts, and the frame structure moves upward while the two wires 12 of the same group of wires 12 approach each other, so that the grid line 40 becomes narrower and higher until the shaping is completed, and then the telescopic part 52 of the second cylinder retracts to move the frame structure out of the target area, completing the printing and shaping process. In this process, the wire 12 will adhere to and carry away some of the slurry of the grid line 40. In the next molding process, when the wire 12 contacts the grid line 40 of the next photovoltaic cell 30, it will adhere to the slurry of the new grid line 40, thereby avoiding wasting slurry.

[0063] Exemplarily, the number of the first linear motion mechanisms 50 is one group, and each group of the first linear motion mechanisms 50 includes two first linear motion mechanisms 50, and the two first linear motion mechanisms 50 in the same group are respectively connected to the opposite sides of the frame structure. Specifically, the frame structure is surrounded by four frames 11, and the two opposite frames 11 parallel to the wire 12 are respectively connected to the telescopic parts 52 of the two first cylinders, and the cylinder barrels of the two first cylinders are fixed on the telescopic parts 52 of the second cylinder through connecting rods. In this way, the stability of the frame structure and the accuracy of the relative position between the wire 12 and the grid wire 40 can be guaranteed during the movement.

[0064] Through the telescopic action of the first cylinder and the second cylinder, the telescopic part 52 of the first cylinder and the telescopic part 52 of the second cylinder can be set to be fixed-length telescopic, thereby ensuring that each group of wires 12 of the frame structure can be accurately aligned with the grid lines 40 on the photovoltaic cell 30 during each molding process, so as to ensure that each grid line 40 can be accurately molded, improve the aspect ratio, and the structure is relatively simple and effective.

[0065] Exemplarily, the size of the frame structure is consistent with that of the screen 20, and the gap formed by the two grid lines 40 in each group of wires 12 corresponds to the hollow structure on the organic film of the screen 20, that is, it precisely corresponds to the slurry grid lines 40 formed on the photovoltaic cell 30, thereby completing the shaping of each grid line 40 to achieve the purpose of improving the aspect ratio.

[0066] Considering that the deviation caused by the movement of the screen 20 may cause the grid lines 40 on the photovoltaic cell 30 to have deviations, in order to ensure that the frame structure can be accurately aligned with the corresponding grid lines 40 during the movement.

[0067] In some embodiments, the number of the first linear motion mechanism 50 is at least one group, and each group of the first linear motion mechanism 50 includes two first linear motion mechanisms 50, and the two first linear motion mechanisms 50 in the same group are respectively arranged on opposite sides of the screen 20; the fixed part 51 (cylinder) of the first linear motion mechanism 50 is rotatably connected to the screen 20, and the telescopic part 52 of the first linear motion mechanism 50 is hinged to the frame structure. The first linear motion mechanism 50 can be one of a hydraulic cylinder, an electric cylinder, and a cylinder. The following description takes the first linear motion mechanism 50 as an example of a first cylinder. The structure of the first cylinder is as follows: Figure 4 shown.

[0068] Exemplarily, the screen 20 and the frame structure are both rectangular structures, and the first cylinder can be a group, that is, two, the fixed parts 51 of the two first cylinders are rotatably connected to the middle part of the relative screen frame (the screen frame parallel to the wire 12) of the screen 20, and the telescopic parts 52 of the two first cylinders are hingedly connected to the two relative frame frames 11 of the frame structure.

[0069] When the screen printing device is in the forming mode, the fixing portion 51 of the first cylinder is rotated from a state parallel to the plane where the screen 20 is located to a state perpendicular to the plane where the screen 20 is located through a corresponding driving mechanism, such as a cylinder, so as to drive the frame structure to enter the target area, and then the frame structure is driven up and down by the expansion and contraction of the first cylinder to complete the forming of the grid line 40. When the grid line 40 is formed, the fixing portion 51 of the first cylinder is rotated from a state perpendicular to the plane where the screen 20 is located to a state parallel to the plane where the screen 20 is located, driving the frame structure to move out of the target area.

[0070] During the movement of the above-mentioned frame structure, since the frame structure is directly set on the screen 20, the silk wires 12 in the frame structure correspond completely and accurately to the hollow structure of the organic film on the screen 20. Therefore, even if the grid lines 40 formed by the screen 20 on the photovoltaic cell 30 have deviations, the silk wires 12 in the frame structure can also completely correspond to the grid lines 40 formed by the photovoltaic cell 30, thereby completing the shaping of the grid lines 40.

[0071] Exemplarily, there may be four first cylinders, the fixed parts 51 of the four first cylinders are rotatably arranged at the four corners of the screen 20, and the telescopic parts 52 of the four first cylinders are hingedly connected to the four corners of the frame structure to enable the frame structure to maintain positioning accuracy and stability in the target area.

[0072] In some embodiments, when the molding device is disposed on the machine platform of the screen printer instead of on the screen 20 , a positioning structure needs to be provided to determine the accurate target area to which the frame structure needs to be moved.

[0073] Exemplarily, the screen printing equipment also includes an image acquisition device and a control device communicatively connected to the image acquisition device, the image acquisition device is used to acquire position information of the grid lines 40 on the screen 20; the control device is used to control each wire 12 of the frame structure to move to the side and below the corresponding grid lines 40 based on the position information of the grid lines 40.

[0074] Since the screen 20 is located above the photovoltaic cell 30, it is not practical to set up an image acquisition device, such as a camera, in the target area. Therefore, the image acquisition device can be set on the frame above the screen 20, and the camera can be used to collect the position information of the grid lines 40 on the screen 20, and the information is sent to the control device, such as a PLC. The PLC controls the motion mechanism of the grid line forming device to accurately move the frame structure to the corresponding position in the target area, thereby completing the narrowing and heightening of the grid lines 40.

[0075] Figure 5 A schematic flow chart of the steps of the method for forming the gate line 40 according to an embodiment of the present invention. Figure 5 As shown, the exemplary embodiment of the present invention further provides a grid line forming method, using the screen printing device in the above embodiment to form a grid line 40 on the photovoltaic cell 30, the forming method comprising:

[0076] Step 501 : Printing grid lines 40 on the photovoltaic cell 30 using a screen 20 .

[0077] The existing screen printing equipment in the photovoltaic cell field can be used. When the photovoltaic cell 30 moves to the ink pad position, it is kept vacuum-fixed, and the screen 20 located above the photovoltaic cell 30 is lowered to the surface of the photovoltaic cell 30 and silver paste is coated on the screen 20. A scraper is used to print the silver paste onto the surface of the photovoltaic cell 30 through the grid line 40 pattern (hollow structure) on the screen 20 to form the grid line 40.

[0078] The screen 20 is lifted and the photovoltaic cell 30 is kept stationary, so as to form a target area between the screen 20 and the photovoltaic cell 30 .

[0079] Step 502 : attach the frame structure to the surface of the photovoltaic cell 30 .

[0080] The telescopic part 52 of the second cylinder is extended, and the frame structure is driven into the target area by the first cylinder located on the telescopic part 52 of the second cylinder. The telescopic part 52 of the first cylinder is controlled to extend to fit the frame structure to the surface of the photovoltaic cell 30, wherein each group of wires 12 is located at the bottom of both sides of the corresponding grid line 40 on the photovoltaic cell 30.

[0081] Step 503 , while lifting the frame structure, move two wires 12 of the same group of wires 12 toward each other.

[0082] The telescopic part 52 of the first cylinder is controlled to retract and the frame structure is lifted while the two wires 12 in each group of wires 12 are controlled to move toward each other. Since the wires 12 have a certain tension, the slurry of the grid wires 40 can be squeezed so that the slurry of the grid wires 40 gathers upward and toward the middle. When the lifting of the frame structure is completed, the frame structure is driven by the telescopic part 52 of the second cylinder to move out of the target area, completing a grid wire 40 forming cycle.

[0083] In some embodiments, the moving speed of the frame structure ranges from 2 μm / s to 5 μm / s, and can be 3 μm / s or 4 μm / s, and the moving speed of the frame structure refers to the rising speed in the vertical direction during the pulling process of the grid line 40; the moving speed of the wire 12 ranges from 1 μm / s to 8 μm / s, and can be 2 μm / s, 3 μm / s, 4 μm / s, 5 μm / s, 6 μm / s or 7 μm / s. The moving speed of the wire 12 refers to the moving speed in the horizontal direction during the pulling process of the grid line 40.

[0084] It should be noted that the moving speeds of the frame structure and the wire 12 are exemplary speeds, and the specific moving speeds are adjusted according to the actual required grid line height and width.

[0085] The technical advantages of the above-mentioned grid line forming method over the prior art are the same as the advantages of the above-mentioned grid line forming device, which will not be described in detail here.

[0086] It should be understood by those skilled in the art that the above embodiments are only for the purpose of clearly illustrating the present invention, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and these changes or modifications are still within the scope of the present invention.

Claims

1. A grid line forming device, characterized in that: Used for adjusting the grid line shape of photovoltaic cells, the forming device comprises a first linear motion mechanism, a frame structure and at least one group of wires, the frame structure comprises two opposite frames; Each group of the silk threads includes two silk threads, and the two ends of each silk thread are slidably arranged on the two frame frames respectively, and the movement directions of the two silk threads in the same group of the silk threads are opposite; The frame structure is connected to the first linear motion mechanism, and a motion direction of the first linear motion mechanism is perpendicular to a plane where the at least one group of wires is located.

2. The molding device according to claim 1, characterized in that: The forming device further comprises two first driving mechanisms arranged on the frame, one of the silk threads in the same group is drivingly connected to one of the first driving mechanisms, and the other silk thread is drivingly connected to the other first driving mechanism.

3. The molding device according to claim 1, characterized in that: The wire has a tension greater than a preset tension.

4. The molding device according to claim 1, characterized in that: The material of the wire includes one of polyimide, nylon or alloy steel.

5. A screen printing device, characterized in that: It comprises a screen and a forming device according to any one of claims 1 to 4; When the printing device is in a forming mode, the frame structure of the forming device is located in a target area, and the target area refers to the area between the screen and the photovoltaic cell sheet; When the printing device is in a printing mode, the frame structure of the forming device is located in other areas except the target area.

6. The screen printing device according to claim 5, characterized in that: The number of the first linear motion mechanisms is at least one group, each group of the first linear motion mechanisms includes two first linear motion mechanisms, and the two first linear motion mechanisms in the same group are respectively arranged on opposite sides of the screen; One end of the first linear motion mechanism is rotatably connected to the screen, and the other end of the first linear motion mechanism is hinged to the frame structure.

7. The screen printing device according to claim 6, characterized in that: The first linear motion mechanism includes one of a hydraulic cylinder, an electric cylinder or a pneumatic cylinder.

8. The screen printing device according to claim 5, characterized in that: The screen printing device further comprises an image acquisition device and a control device in communication with the image acquisition device, wherein the image acquisition device is used to acquire position information of the grid lines on the screen; The control device is used to control each of the wires of the frame structure to move to the side and below the corresponding grid line based on the position information of the grid line.

9. A grid line forming method, characterized in that: The grid lines are formed on the photovoltaic cell sheet using the screen printing device according to any one of claims 5 to 8, wherein the forming method comprises: Printing the grid lines on the photovoltaic cell sheet by screen printing; Attaching the frame structure to the surface of the photovoltaic cell; The frame structure is lifted while two of the wires in the same group of wires are moved toward each other.

10. The grid line forming method according to claim 9, characterized in that: In a direction perpendicular to the plane where the at least one group of wires is located, the speed at which the frame structure moves away from the photovoltaic cell sheet is in a range of 2 μm / s to 5 μm / s; and / or, The moving speed of the wire ranges from 1 μm / s to 8 μm / s.

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