Photovoltaic module processing method and photovoltaic module processing equipment

Abstract

The invention relates to a photovoltaic module processing method and photovoltaic module processing equipment. The photovoltaic module processing method comprises the following steps that a solar cell and a welding strip are provided, the solar cell comprises a cell piece, a positive electrode grid line and a negative electrode grid line, and the positive electrode grid line and the negative electrode grid line are located on the surface of the cell piece. And applying a reverse voltage to the solar cell through the positive grid line and the negative grid line. And welding the welding strip on the solar cell by adopting laser welding. In the processing method of the photovoltaic module, reverse voltage is applied to the solar cell and laser welding is adopted, so that charge carriers in the solar cell can be excited to generate several amperes of current, and free carriers are forced to pass through a grid line to be in contact with a cell piece, so that the contact resistance between the grid line and the cell piece can be reduced; ohmic resistance between the grid line and the battery piece is improved, and the photoelectric conversion efficiency of the photovoltaic module is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, in particular to a photovoltaic module processing method and a photovoltaic module processing device. BACKGROUND

[0002] In the preparation process of a solar cell, metal paste is usually coated on the surface of a cell sheet, and then sintering treatment is performed to form positive and negative grid lines on the cell sheet, and then a plurality of solar cells are welded together by a welding strip. In the formation process of the positive and negative grid lines, the grid lines are in contact with the cell sheet to form ohmic contact, thereby improving the open circuit voltage and fill factor of the solar cell. However, after sintering treatment, there are still under-sintered contact points in the solar cell, which makes the series resistance of the solar cell larger, thereby restricting the improvement of the photoelectric conversion efficiency of the photovoltaic module. SUMMARY

[0003] Therefore, it is necessary to provide a photovoltaic module processing method and a photovoltaic module processing device. The photovoltaic module processing method can improve the ohmic contact between the grid lines and the cell sheet, and promote the improvement of the photoelectric conversion efficiency of the photovoltaic module.

[0004] A photovoltaic module processing method, comprising the following steps: providing a solar cell and a welding strip, the solar cell comprising a cell sheet, a positive grid line and a negative grid line, the positive grid line and the negative grid line being located on the surface of the cell sheet; applying a reverse voltage to the solar cell through the positive grid line and the negative grid line; and welding the welding strip on the solar cell by laser welding.

[0005] In some embodiments, the reverse voltage has a magnitude of 10V-24V.

[0006] In some embodiments, the reverse voltage has a duration of 1s-3s.

[0007] In some embodiments, the reverse voltage is a constant reverse voltage.

[0008] In some embodiments, the laser welding uses a pulsed laser.

[0009] In some embodiments, the pulsed laser has a pulse power of 55W-62W.

[0010] In some embodiments, the pulsed laser has a welding temperature of 180℃-240℃.

[0011] In some embodiments, the pulsed laser has a welding time of 300ms-500ms.

[0012] In some embodiments, the pulse laser has a waveform including one or more of a square wave and a sine wave.

[0013] In some embodiments, the positive grid lines and the negative grid lines are located on the same surface of the cell.

[0014] In some embodiments, the positive grid lines include one of silver grid lines, copper grid lines, and gold grid lines.

[0015] In some embodiments, the negative grid lines include one of silver grid lines, copper grid lines, and gold grid lines.

[0016] In some embodiments, the cell includes a silicon-based cell.

[0017] A photovoltaic module processing device includes a frame, a transmission member, a power source, and a laser welder; the transmission member is connected to the frame for transmitting a solar cell and a solder strip; the power source is used to apply a reverse voltage to the solar cell; and the laser welder is used to weld the solder strip on the solar cell.

[0018] In some embodiments, the photovoltaic module processing device further includes a conductive pressure net connected to the frame; the conductive pressure net is located upstream of the laser welder in the transmission direction of the transmission member; the conductive pressure net is electrically connected to the power source, and the conductive pressure net is used to press the solder strip on the solar cell and apply the reverse voltage to the solar cell by the power source.

[0019] In some embodiments, the photovoltaic module processing device further includes a position detector connected to the frame; the position detector is located upstream of the conductive pressure net in the transmission direction of the transmission member; and the position detector is used to detect the position of the solar cell on the transmission member.

[0020] In some embodiments, the photovoltaic module processing device further includes a heating member; the heating member is connected to the transmission member for heating the solar cell.

[0021] In some embodiments, the photovoltaic module processing device further includes a scanning member connected to the frame; the scanning member is located upstream of the laser welder in the transmission direction of the transmission member; and the scanning member is used to scan the pad information of the surface of the solar cell, thereby providing the laser welder with welding information.

[0022] The reverse voltage is applied to the solar cell and the laser welding is adopted in the photovoltaic module processing method, so that the charge carriers in the solar cell are excited to generate several amperes of current, and the free carriers are forced to pass through the grid lines (positive grid lines and negative grid lines) and the solar cell, so that the contact resistance between the grid lines and the solar cell is reduced, the ohmic resistance between the grid lines and the solar cell is improved, and the photoelectric conversion efficiency of the photovoltaic module is improved.

[0023] Further, the laser welding can effectively fix the connection structure between the grid lines and the solar cell, which is conducive to enhancing the stability of the welding structure and improving the structural stability of the photovoltaic module.

[0024] Further, the laser welding facilitates precise energy control, which can reduce the thermal damage to the solar cell during welding, reduce the risk of burning and breaking of the grid lines, improve the consistency and reliability of welding, and further improve the production yield of the photovoltaic module.

[0025] Further, the laser welding is a non-contact welding. The laser welding can reduce the fragment rate of the solar cell and reduce the production cost of the photovoltaic module.

[0026] When the photovoltaic module is processed by using the photovoltaic module processing device, the solar cell and the solder strip can be placed on the transmission member, and the reverse voltage is applied to the solar cell by the power supply. Then the solar cell and the solder strip are transmitted to the laser welder, and the solder strip is welded on the solar cell by the laser welder. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structure schematic diagram of the solar cell in an embodiment of the present application.

[0028] Figure 2 It is a structure schematic diagram of the photovoltaic module processing device in an embodiment of the present application.

[0029] MARKED DESCRIPTION IN THE DRAWING:

[0030] 10, solar cell; 101, solar cell piece; 102, grid line; 103, solder pad; 104, tin paste; 20, photovoltaic module processing device; 201, rack; 202, transmission member; 203, laser welder; 204, conductive mesh; 205, position detector; 206, heating member; 207, scanning member; 208, first driving member; 209, second driving member; 210, bearing table. DETAILED DESCRIPTION

[0031] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, a detailed description of specific embodiments of this application is provided below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0032] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] One embodiment of this application provides a method for processing a photovoltaic module. The method includes the following steps: providing a solar cell and solder ribbon; the solar cell includes a cell sheet, positive grid lines, and negative grid lines, the positive and negative grid lines being located on the surface of the cell sheet; applying a reverse voltage to the solar cell through the positive and negative grid lines; and welding the solder ribbon onto the solar cell using laser welding.

[0036] Understandably, in the fabrication process of solar cells, a metal paste is typically first coated onto the surface of the cell, then positive and negative grid lines are formed on the cell through sintering, and finally multiple solar cells are welded together using solder ribbons. During the formation of the positive and negative grid lines, the grid lines contact the cell to form an ohmic contact, thereby improving the open-circuit voltage and fill factor of the solar cell. However, after sintering, under-sintered contact points still exist in the solar cell, resulting in a relatively high series resistance and limiting the improvement of the photovoltaic module's photoelectric conversion efficiency. In the photovoltaic module processing method of this embodiment, applying a reverse voltage to the solar cell and using laser welding can excite charge carriers in the solar cell, generating a current of several amperes. Free charge carriers are forced to contact the cell through the grid lines, thus reducing the contact resistance between the grid lines and the cell, improving the ohmic resistance between the grid lines and the cell, and thereby improving the photoelectric conversion efficiency of the photovoltaic module.

[0037] Furthermore, laser welding can effectively fix the connection structure between the grid lines and the solar cells, which helps to enhance the stability of the welded structure and thus improve the structural stability of the photovoltaic module.

[0038] Furthermore, laser welding facilitates precise energy control, which can reduce thermal damage to the cells during the welding process, lower the risk of grid lines burning through or breaking, improve the consistency and reliability of the welding, and thus improve the production yield of photovoltaic modules.

[0039] Furthermore, laser welding is a non-contact welding method. Using laser welding can reduce the breakage rate of solar cells and lower the production cost of photovoltaic modules.

[0040] Understandably, when applying a reverse voltage to a solar cell through the positive and negative grid lines, an external power supply can be used. For example, the positive grid line can be electrically connected to the negative terminal of the power supply, and the negative grid line can be electrically connected to the positive terminal of the power supply. This allows a reverse voltage to be applied to the solar cell through the positive and negative grid lines.

[0041] In some implementations, the reverse voltage is between 10V and 24V. If the reverse voltage is too low, fewer charge carriers are excited in the solar cell, resulting in a poor improvement in the ohmic contact between the grid lines and the cell. If the reverse voltage is too high, it may cause excessive damage to the solar cell structure, affecting its performance and consequently negatively impacting the performance of the photovoltaic module. Optionally, the reverse voltage can be 10V, 11V, 12V, 13V, 14V, 15V, 16V, 17V, 18V, 19V, 20V, 21V, 22V, 23V, 24V, etc. It is understood that other suitable choices can be made within the 10V to 24V range for the reverse voltage.

[0042] In some implementations, the duration of the reverse voltage is 1 to 3 seconds. If the duration of the reverse voltage is too short, it is difficult to adequately improve the ohmic contact between the grid lines and the solar cells, resulting in poor improvement. If the duration of the reverse voltage is too long, it may cause excessive damage to the solar cell structure, affecting the performance of the solar cell and consequently adversely affecting the performance of the photovoltaic module. Optionally, the duration of the reverse voltage can be 1 second, 1.2 seconds, 1.5 seconds, 1.8 seconds, 2 seconds, 2.2 seconds, 2.5 seconds, 2.8 seconds, 3 seconds, etc. It is understood that other suitable choices can be made within the range of 1 to 3 seconds for the duration of the reverse voltage.

[0043] In some implementations, applying a reverse voltage means applying a constant reverse voltage. This can stabilize and improve the ohmic contact between the grid lines and the solar cells, further improving the ohmic contact between the grid lines and the solar cells. It is understood that applying a constant reverse voltage means applying a constant voltage to the solar cell while applying a reverse voltage.

[0044] In some implementations, the laser type used in laser welding includes pulsed lasers. Pulsed lasers have low thermal stress, which is beneficial for improving weld quality.

[0045] Optionally, the pulse power of the pulsed laser is 55W to 62W. For example, the pulse power of the pulsed laser is 55W, 56W, 57W, 58W, 59W, 60W, 61W, 62W, etc. Understandably, other suitable choices can be made within the range of 55W to 62W for the pulsed laser.

[0046] Optionally, the welding temperature of the pulsed laser is 180℃~240℃. For example, the welding temperatures of the pulsed laser are 180℃, 190℃, 200℃, 210℃, 220℃, 230℃, 240℃, etc. Understandably, other suitable choices can be made within the range of 180℃~240℃ for the pulsed laser welding temperature.

[0047] Optionally, the pulsed laser welding time can be between 300ms and 500ms. For example, pulsed laser welding times can be 300ms, 320ms, 350ms, 380ms, 400ms, 420ms, 450ms, 480ms, and 500ms. Understandably, other suitable options can be selected within the 300ms to 500ms range for the pulsed laser welding time.

[0048] Optionally, the waveform of the pulsed laser includes one or more of square waves and sine waves.

[0049] In some implementations, the positive and negative grid lines are located on the same surface of the solar cell. In this case, there are no positive and negative grid lines on one surface of the solar cell, which reduces the shading of sunlight by the grid lines, improves the utilization rate of sunlight by the photovoltaic module, and enhances the photoelectric conversion efficiency of the photovoltaic module. It is understood that the positive and negative grid lines are located on the back side of the solar cell.

[0050] Please see Figure 1 The structure of a solar cell 10 according to one embodiment of this application is shown. The solar cell 10 includes a cell 101, grid lines 102, and pads 103 (PADs). The grid lines 102 are located on the back side of the cell 101; there are no grid lines 102 on the front side of the cell 101. It is understood that the grid lines 102 include positive and negative grid lines. The grid lines 102 are distributed in an interdigitated pattern. The pads 103 indicate the positions where the cell 101 contacts the solder ribbon. Solder paste 104 is provided on the pads 103, allowing the solder ribbon to be soldered onto the solar cell 10 during laser soldering.

[0051] In some embodiments, the positive electrode grid line includes one of silver grid lines, copper grid lines, and gold grid lines. Silver grid lines, copper grid lines, and gold grid lines have good conductivity, which can improve charge transfer efficiency and improve the photoelectric conversion efficiency of photovoltaic modules.

[0052] In some embodiments, the negative electrode grid line includes one of silver grid lines, copper grid lines, and gold grid lines. Silver grid lines, copper grid lines, and gold grid lines have good conductivity, which can improve charge transfer efficiency and improve the photoelectric conversion efficiency of photovoltaic modules.

[0053] In some embodiments, the solar cell includes a silicon-based solar cell. Silicon-based solar cells can be obtained using silicon-based solar cells as raw materials.

[0054] Please see Figure 2 This application provides a photovoltaic module processing apparatus 20 according to one embodiment. The photovoltaic module processing apparatus 20 includes a frame 201, a transmission component 202, a power supply (not shown), and a laser welder 203. The transmission component 202 is connected to the frame 201 for transporting solar cells and solder strips. The power supply is used to apply a reverse voltage to the solar cells. The laser welder 203 is used to weld solder strips onto the solar cells.

[0055] When processing photovoltaic modules using the photovoltaic module processing equipment 20 in this embodiment, solar cells and solder ribbons can be placed on the transport member 202, and a reverse voltage can be applied to the solar cells using a power source. The solar cells and solder ribbons are then transported to the laser welder 203, where the solder ribbons are welded onto the solar cells.

[0056] Optionally, a power supply is connected to the rack 201. The laser welder 203 is connected to the rack 201.

[0057] It is understood that a solar cell includes a solar cell, positive grid lines, and negative grid lines, with the positive and negative grid lines located on the surface of the solar cell. By using the photovoltaic module processing equipment 20 of this embodiment to process the photovoltaic module, charge carriers in the solar cell can be excited, generating a current of several amperes. Free charge carriers are forced to contact the solar cell through the grid lines, thus reducing the contact resistance between the grid lines and the solar cell, improving the ohmic resistance between them, and thereby increasing the photoelectric conversion efficiency of the photovoltaic module.

[0058] It is also understood that when the solar cell and solder ribbon are placed on the transport member 202, the solder ribbon is positioned above the solar cell, and the relative position of the solder ribbon and the solar cell can be set according to the structural design and welding requirements of the photovoltaic module. For photovoltaic modules, the solder ribbon being positioned above the solar cell and the relative position of the solder ribbon and the solar cell can be configured according to conventional practices in the art, and will not be elaborated further here.

[0059] It is also understood that the photovoltaic module processing equipment 20 further includes a first driving component 208, which is connected to the frame 201, and the driving end of the first driving component 208 is connected to the laser welder 203. The driving action of the first driving component 208 can adjust the position of the laser welder 203, thereby adjusting the relative position between the laser welder 203 and the solar cells and welding strips on the transmission component 202, to promote efficient welding processing.

[0060] It is also understandable that when a reverse voltage is applied to the solar cell via a power source, the magnitude and duration of the reverse voltage can be selected accordingly in the aforementioned photovoltaic module processing method, and will not be elaborated here. When welding is performed using the laser welder 203, the laser type, pulse energy, pulse density, pulse waveform, and other parameters of the laser welder 203 can be selected accordingly in the aforementioned photovoltaic module processing method, and will not be elaborated here.

[0061] In some embodiments, the transmission member 202 may be a belt conveyor 202. Optionally, the photovoltaic module processing equipment 20 further includes a second drive member 209. The second drive member 209 is connected to the frame 201, and the drive end of the second drive member 209 is connected to the transmission member 202. The driving action of the second drive member 209 can drive the transmission member 202 to move, thereby efficiently transmitting solar cells and welding strips.

[0062] Please refer to it again. Figure 2In some embodiments, the photovoltaic module processing equipment 20 further includes a voltage-conducting grid 204 connected to the frame 201. In the transmission direction of the transmission member 202, the voltage-conducting grid 204 is located upstream of the laser welder 203. The voltage-conducting grid 204 is electrically connected to a power source and is used to press the solder ribbon onto the solar cell and apply a reverse voltage to the solar cell via the power source. By providing the voltage-conducting grid 204, the position of the solder ribbon on the solar cell can be fixed while applying a reverse voltage, reducing the risk of solder ribbon misalignment during processing.

[0063] Please refer to it again. Figure 2 In some embodiments, the photovoltaic module processing equipment 20 further includes a position detector 205 connected to the frame 201. The position detector 205 is located upstream of the conductive grid 204 in the transmission direction of the transmission member 202. The position detector 205 is used to detect the position of the solar cells on the transmission member 202. By setting the position detector 205, the position of the solar cells can be detected, and it can be determined whether the solar cells are transmitted to the conductive grid 204 according to a preset position, thereby improving the processing accuracy of the photovoltaic modules. It is understood that when the position detector 205 detects that the position of the solar cell is not the preset position, a controller (not shown in the figure) can control a return member (not shown in the figure) to adjust the position of the solar cell so that the solar cell is transmitted to the conductive grid 204 according to the preset position. Optionally, the position detector 205 can be an ultra-high-speed profile detector.

[0064] Please refer to it again. Figure 2 In some embodiments, the photovoltaic module processing equipment 20 further includes a heating element 206. The heating element 206 is connected to the transmission element 202 for heating the solar cells. By heating the solar cells through the heating element 206, the temperature of the solar cells can be controlled, ensuring that the solar cells have a suitable temperature during the welding process. This reduces the risk of incomplete soldering due to excessive cooling of the solar cells, improves the quality of laser welding, and ultimately increases the production yield of photovoltaic modules.

[0065] Optionally, in Figure 2 In the structure shown, there are two heating elements 206. Along the transmission direction of the transmission element 202, the two heating elements 206 are located on opposite sides of the laser welder 203. This allows for convenient temperature control of the solar cells before and after laser welding, ensuring good welding quality of the photovoltaic module. Optionally, the heating element 206 can be a heating base plate.

[0066] Please refer to it again. Figure 2In some embodiments, the photovoltaic module processing equipment 20 further includes a scanner 207 connected to the frame 201. The scanner 207 is located upstream of the laser welder 203 in the transmission direction of the transmission member 202. The scanner 207 is used to scan the pad information on the surface of the solar cell, thereby providing welding information to the laser welder 203. The location of the pads on the solar cell can be scanned by the scanner 207, facilitating the laser welder 203 to weld the solder strip at the pad location. It is understood that solder paste is provided on the pads, and during laser welding, the solder strip can be welded to the solar cell using the solder paste. Optionally, the scanner 207 is a camera. The laser welder 203 welds the solder strip using the pad information recorded by the camera.

[0067] It is understandable that when the photovoltaic module processing equipment 20 includes a voltage conduction network 204, the scanning element 207 is located between the voltage conduction network 204 and the laser welder 203 in the transmission direction of the transmission element 202.

[0068] Please refer to it again. Figure 2 In some embodiments, the photovoltaic module processing equipment 20 further includes a support platform 210. In the transmission direction of the transmission member 202, the support platform 210 is located upstream of the position detector 205. The support platform 210 can support solar cells and temporarily store them.

[0069] Another embodiment of this application provides a photovoltaic module processing method. This photovoltaic module processing method uses the aforementioned photovoltaic module processing equipment 20. The photovoltaic module processing method includes the following steps: placing a solar cell and a solder ribbon on a transport member 202, and applying a reverse voltage to the solar cell using a power source. Then, the solar cell and solder ribbon are transported to a laser welder 203, where the solder ribbon is welded to the solar cell using the laser welder 203.

[0070] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0071] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.

Claims

1. A method for processing photovoltaic modules, characterized in that, Includes the following steps: A solar cell and a solder ribbon are provided, the solar cell comprising a cell, a positive grid line and a negative grid line, the positive grid line and the negative grid line being located on the surface of the cell; A reverse voltage is applied to the solar cell through the positive grid line and the negative grid line; The welding strip is welded onto the solar cell using laser welding.

2. The photovoltaic module processing method according to claim 1, characterized in that, The magnitude of the reverse voltage is 10V~24V; and / or, The duration of the reverse voltage is 1s to 3s; and / or, Applying a reverse voltage means applying a constant reverse voltage.

3. The photovoltaic module processing method according to claim 1, characterized in that, The laser type used in the laser welding includes pulsed laser.

4. The photovoltaic module processing method according to claim 3, characterized in that, The pulsed laser has a pulse power of 55W~62W; and / or, The welding temperature of the pulsed laser is 180℃~240℃; and / or, The welding time of the pulsed laser is 300ms~500ms; and / or, The waveform of the pulsed laser includes one or more of square waves and sine waves.

5. The photovoltaic module processing method according to any one of claims 1 to 4, characterized in that, The positive grid line and the negative grid line are located on the same surface of the battery cell.

6. The photovoltaic module processing method according to any one of claims 1 to 4, characterized in that, The positive electrode grid line includes one of silver grid lines, copper grid lines, and gold grid lines; and / or, The negative electrode grid line includes one of silver grid lines, copper grid lines, and gold grid lines; and / or, The solar cells include silicon-based solar cells.

7. A photovoltaic module processing equipment, characterized in that, The device includes a frame, a transmission component, a power supply, and a laser welder; the transmission component is connected to the frame for transporting solar cells and solder strips; the power supply is used to apply a reverse voltage to the solar cells; and the laser welder is used to weld the solder strips onto the solar cells.

8. The photovoltaic module processing equipment according to claim 7, characterized in that, The photovoltaic module processing equipment also includes a voltage-conducting grid connected to the frame; in the transmission direction of the transmission component, the voltage-conducting grid is located upstream of the laser welder; the voltage-conducting grid is electrically connected to the power supply, and the voltage-conducting grid is used to press the welding strip onto the solar cell and apply the reverse voltage to the solar cell through the power supply.

9. The photovoltaic module processing equipment according to claim 8, characterized in that, The photovoltaic module processing equipment also includes a position detector connected to the frame; in the transmission direction of the transmission component, the position detector is located upstream of the conductive grid; the position detector is used to detect the position of the solar cell on the transmission component.

10. The photovoltaic module processing equipment according to any one of claims 7 to 9, characterized in that, The photovoltaic module processing equipment further includes a heating element; the heating element is connected to the transmission element for heating the solar cells; and / or... The photovoltaic module processing equipment also includes a scanning element connected to the frame; in the transmission direction of the transmission element, the scanning element is located upstream of the laser welder; the scanning element is used to scan the pad information on the surface of the solar cell, thereby providing welding information to the laser welder.

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