Preparation method of photovoltaic module, battery string and photovoltaic module

Abstract

The invention discloses a preparation method of a photovoltaic module, a battery string and the photovoltaic module, and belongs to the technical field of photovoltaic modules. The preparation method of the photovoltaic module comprises the following steps: providing a battery piece, wherein a welding spot is arranged on the surface of the battery piece; providing a connecting line, laying the connecting line on the surface of the battery piece, and enabling the connecting line to at least partially cover the welding spot; and irradiating the welding spot through a laser welding device so as to weld the connecting line on the surface of the battery piece.

Description

[0001] This application claims the priority of a Chinese patent application with the application number 202311621867.4 and the title "Preparation Method of Photovoltaic Module, Battery String and Photovoltaic Module" filed with the Chinese Patent Office on November 29, 2023, the entire content of which is incorporated herein by reference. Technical Field

[0002] This application relates to the technical field of photovoltaic modules, and specifically relates to a preparation method of photovoltaic modules, a battery string and a photovoltaic module. Background Art

[0003] As the core component of a photovoltaic module, a battery string can convert solar energy into electrical energy. A battery string usually includes a plurality of battery cells arranged at intervals, and adjacent two battery cells are connected in series by welding wires to form a battery string.

[0004] In the prior art, an infrared welding method is usually adopted, one end of a welding wire is welded to the surface of a battery cell, and the other end of the welding wire is welded to the surface of another adjacent battery cell to connect the adjacent two battery cells in series. In the existing infrared welding method, the welding wire and the battery cell are usually transported into a heating device, and the welding wire and the battery cell are heated by the heating device to weld the welding wire to the surface of the battery cell.

[0005] However, in the existing infrared welding method, the welding wire expands at high temperature during the welding process, and after the welding is completed, the welding wire cools and shrinks. During the shrinking process of the welding wire, the welding wire will pull on the battery cell, causing the battery cell to bend or even break, affecting the process yield of the photovoltaic module. Summary of the Invention

[0006] This application discloses a preparation method of a photovoltaic module, a battery string and a photovoltaic module to solve or at least partially solve the problem in the prior art that when welding a welding wire to the surface of a battery cell by an infrared welding method, it is easy to cause the battery cell to bend or even break, affecting the process yield of the photovoltaic module.

[0007] To solve the above technical problems, this application is implemented as follows:

[0008] In a first aspect, this application discloses a preparation method of a photovoltaic module, the method includes: providing a battery cell, on the surface of which there are welding points; providing a connecting wire, laying the connecting wire on the surface of the battery cell so that the connecting wire at least partially covers the welding points; irradiating the area where the welding points are located with a laser to weld the connecting wire to the surface of the battery cell.

[0009] Optionally, at least one fine grid line extending in a first direction is provided on the surface of the cell, and the projection of the solder joint on the cell at least partially overlaps the projection of the fine grid line on the cell; the method of laying the connection line on the surface of the cell includes: laying the connection line on the surface of the cell along a second direction, the second direction intersecting the first direction; welding the connection line to the surface of the cell by laser irradiating the area where the solder joint is located includes: welding the connection line to the solder joint by laser irradiating the area where the solder joint is located, so that the connection line is electrically connected to the fine grid line through the solder joint.

[0010] Optionally, the connection line includes a connection line matrix and a bonding layer coated on the connection line matrix, and the method of welding the connection line to the solder joint by laser irradiating the solder joint includes: welding the connection line to the solder joint by laser irradiating the solder joint, so that the bonding layer of the connection line fuses with the solder joint to form a laser welding area, thereby welding the connection line to the solder joint.

[0011] Optionally, there are multiple fine grid lines, and the multiple fine grid lines are arranged at intervals along the second direction, the solder joints include at least two, and the at least two solder joints are arranged at intervals along the second direction. The projection of each solder joint on the cell at least partially overlaps the projection of one of the fine grid lines on the cell; the method of welding the connection line to the solder joint by laser irradiating the solder joint further includes: identifying the at least two solder joints to plan the light irradiation path of the laser; controlling the laser to run along the light irradiation path, and respectively irradiating the areas where the at least two solder joints are located by the laser to weld the connection line to the at least two solder joints.

[0012] Optionally, the laser includes at least two laser beams; alternatively, the method of welding the connection line to the solder joint by laser irradiating the solder joint further includes: identifying the positions of the at least two solder joints, moving the at least two laser beams so that each laser beam is oppositely arranged with a solder joint; irradiating the areas where the corresponding solder joints are located by each laser beam to weld the connection line to the solder joint.

[0013] Optionally, the instantaneous temperature when the laser irradiates the area where the solder joint is located is greater than or equal to 135 degrees and less than or equal to 185 degrees.

[0014] Optionally, along the direction perpendicular to the plane where the cell is located, the projection of the laser welding area on the cell falls within the projection of the solder joint on the cell, and the area of the laser welding area accounts for 10% to 70% of the area of the solder joint.

[0015] Second aspect, the present application discloses a battery string, the battery string includes: battery cells, solder joints are provided on the surface of the battery cells; connection lines, the connection lines are laid on the surface of the battery cells and at least partially cover the solder joints, at the position where the solder joints are located, the connection lines are welded to the surface of the battery cells by laser welding.

[0016] Optionally, at least one fine grid line extending in a first direction is provided on the surface of the battery cell, and at least a part of the projection of the solder joint on the battery cell overlaps with the projection of the fine grid line on the battery cell; the connection line extends in a second direction, and at the position where the solder joint is located, the connection line is welded to the solder joint by laser welding, so that the connection line is electrically connected to the fine grid line through the solder joint; wherein, the second direction intersects the first direction.

[0017] Optionally, the connection line includes a connection line matrix and a bonding layer coated on the connection line matrix, the bonding layer melts with the solder joint to form a laser welding area, and the connection line is welded to the solder joint through the laser welding area.

[0018] Optionally, the laser welding area includes a fusion area of the bonding layer and the solder joint.

[0019] Optionally, along the direction perpendicular to the plane where the battery cell is located, the shape of the laser welding area includes at least one of a circle, a triangle, a square, and a rectangle; and the projection of the laser welding area on the battery cell falls within the projection of the solder joint on the battery cell.

[0020] Optionally, along the direction perpendicular to the plane where the battery cell is located, the area of the laser welding area accounts for 10% to 70% of the area of the solder joint.

[0021] Optionally, along the first direction, the width of the solder joint is greater than the width of the connection line; along the second direction, the length of the solder joint is greater than the width of the fine grid line.

[0022] Optionally, there are multiple fine grid lines, and the multiple fine grid lines are arranged at intervals along the second direction, the solder joints include at least two, the at least two solder joints are arranged at intervals along the second direction, and the projection of each solder joint on the battery cell at least partially overlaps with the projection of one of the fine grid lines on the battery cell; wherein, at the positions where the at least two solder joints are located, the connection line is welded to the corresponding solder joint by laser welding.

[0023] Optionally, the number of the solder joints is 2 to 8, and the 2 to 8 solder joints are arranged at intervals along the second direction.

[0024] Optionally, the solder joints include five or six, and the five or six solder joints are arranged at intervals along the second direction.

[0025] Optionally, the bonding layer includes one of a tin-lead layer, a tin-lead-bismuth layer, and a tin-bismuth layer.

[0026] Optionally, the solar cell includes a first surface and a second surface arranged opposite to each other. A first solder joint is provided on the first surface, and a second solder joint is provided on the second surface; the connection line includes a first connection line and a second connection line. The first connection line is laid on the first surface and at least partially covers the first solder joint. At the position where the first solder joint is located, the first connection line is welded to the first surface by laser welding; the second connection line is laid on the second surface and at least partially covers the second solder joint. At the position where the second solder joint is located, the second connection line is welded to the second surface by laser welding.

[0027] In a third aspect, the present application also discloses a photovoltaic module, which includes at least two of the battery strings in the second direction, and the at least two battery strings are arranged at intervals.

[0028] Optionally, the photovoltaic module further includes: a bus bar, the bus bar is provided between two adjacent battery strings, or the bus bar is provided on one side of the battery string away from another adjacent battery string; the connection line extends to the surface of the bus bar and is welded to the surface of the bus bar by laser welding.

[0029] Optionally, the projection area of the connection line on the plane where the bus bar is located is the welding area. Along the extension direction of the connection line, the length of the welding area is greater than or equal to 0.1 mm and less than or equal to 7 mm; along the length direction of the bus bar, the width of the welding area is greater than or equal to 0.1 mm and less than or equal to 0.6 mm.

[0030] The present application discloses a method for manufacturing a photovoltaic module, a battery string, and a photovoltaic module. The method for manufacturing the photovoltaic module includes: providing a solar cell, and solder joints are provided on the surface of the solar cell; providing a connection line, laying the connection line on the surface of the solar cell so that the connection line at least partially covers the solder joints; irradiating the area where the solder joints are located by laser to weld the connection line to the surface of the solar cell. In the method for manufacturing a photovoltaic module disclosed in the present application, the connection line is welded to the surface of the solar cell by irradiating the area where the solder joints are located with laser. By using the method for manufacturing a photovoltaic module disclosed in the present application to manufacture a photovoltaic module, the connection line is not prone to thermal expansion and contraction, and the process yield of the photovoltaic module is relatively high. Description of the Drawings

[0031] Figure 1Shows the process flow of the method for manufacturing the photovoltaic module described in the embodiments of the present application Figure 1 ;

[0032] Figure 2 Shows the process flow of the method for manufacturing the photovoltaic module described in the embodiments of the present application Figure 2 ;

[0033] Figure 3 Shows the process flow of the method for manufacturing the photovoltaic module described in the embodiments of the present application Figure 3 ;

[0034] Figure 4 Shows the schematic diagram of the manufacturing process of the photovoltaic module described in the embodiments of the present application Figure 1 ;

[0035] Figure 5 Shows the schematic diagram of the manufacturing process of the photovoltaic module described in the embodiments of the present application Figure 2 ;

[0036] Figure 6 Shows the top view of the battery string described in the embodiments of the present application;

[0037] Figure 7 Shows the cross-sectional view of the battery string described in the embodiments of the present application;

[0038] Figure 8 Shows the schematic structural diagram of the solder joint described in the embodiments of the present application;

[0039] Figure 9 Shows the schematic structural diagram of the bus bar described in the embodiments of the present application;

[0040] Figure 10 Shows the schematic structural diagram of the solder joint described in the embodiments of the present application.

[0041] Reference numerals:

[0042] 10: cell; 11: solder joint; 12: fine grid line;

[0043] 20: connection line; 21: connection line base; 22: bonding layer;

[0044] 30: laser welding area;

[0045] 40: laser welding device; 41: laser head; 42: CCD camera; 43: shutter; 44: optical fiber;

[0046] 50: bus bar;

[0047] A: first direction; B: second direction. Detailed implementation manners

[0048] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of the present invention.

[0049] It should be understood that the "one embodiment" or "an embodiment" mentioned throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of the present invention. Therefore, the "in one embodiment" or "in an embodiment" that appears throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures, or characteristics can be combined in one or more embodiments in any suitable manner.

[0050] Referring to Figure 1 , the flow of the preparation method of the photovoltaic module described in the embodiment of the present application is shown Figure 1 ; referring to Figure 2 , the flow of the preparation method of the photovoltaic module described in the embodiment of the present application is shown Figure 2 ; referring to Figure 3 , the flow of the preparation method of the photovoltaic module described in the embodiment of the present application is shown Figure 3 ; referring to Figure 4 , the schematic diagram of the preparation process of the photovoltaic module described in the embodiment of the present application is shown Figure 1 ; referring to Figure 5 , the schematic diagram of the preparation process of the photovoltaic module described in the embodiment of the present application is shown Figure 2 .

[0051] Next, the preparation method of the photovoltaic module disclosed in the present application will be described in detail with reference to the accompanying drawings through specific embodiments.

[0052] As Figure 1 shown, the preparation method of the photovoltaic module in an embodiment of the present application is shown, and the method includes:

[0053] Step 101, provide a battery cell 10, and solder joints 11 are provided on the surface of the battery cell 10.

[0054] The battery cell 10 in the embodiment of the present application is the core component of the photovoltaic module, which can convert solar energy into electrical energy. Among them, solder joints 11 are provided on the surface of the battery cell 10, and the connection line 20 is welded to the surface of the battery cell 10 through the area where the solder joints 11 are located.

[0055] It should be noted that, in the embodiments of the present application, the metal paste can be printed on the surface of the battery cell 10 by screen printing to form the solder joints 11. Among them, the metal paste can be silver paste, can be aluminum paste, or other metal pastes. In the embodiments of the present application, there is no specific limitation on the specific type of the metal paste. In actual use, those skilled in the art can select according to needs. In addition, electroplating, laser transfer printing and other methods can also be used to form the solder joints 11.

[0056] Exemplarily, in the embodiments of the present application, at least one fine grid line 12 extending along the first direction A can be arranged on the surface of the battery cell 10, so that at least part of the projection of the solder joint 11 on the battery cell 10 overlaps with the projection of the fine grid line 12 on the battery cell 10.

[0057] That is to say, in the embodiments of the present application, at least one fine grid line 12 extending along the first direction A is arranged on the surface of the battery cell 10, and the current generated by the battery cell 10 is collected through the fine grid line 12. Specifically, the metal paste can also be printed on the surface of the battery cell 10 by screen printing to form the fine grid line 12 on the surface of the battery cell 10. Among them, at least part of the projection of the solder joint 11 on the battery cell 10 overlaps with the projection of the fine grid line 12 on the battery cell 10. So as to weld the connection line 20 to the fine grid line 12 through the area where the solder joint 11 is located, and make the connection line 20 electrically connected to the fine grid line 12 through the solder joint 11, so that the current collected by the fine grid line 12 can be collected through the connection line 20.

[0058] It should be noted that the connection line 20 in the embodiments of the present application has conductivity. It can collect the current collected by the fine grid line 12. Specifically, the connection line 20 can be a welding tape or a welding wire. There is no excessive limitation on the specific type of the connection line 20 in the present application. In actual use, those skilled in the art can select according to needs.

[0059] Step 102: Provide the connection line 20, lay the connection line 20 on the surface of the battery cell 10, so that the connection line 20 at least partially covers the solder joint 11.

[0060] Specifically, the connection line 20 can be laid on the surface of the battery cell 10 along the second direction B, so that the connection line 20 at least partially covers the solder joint 11. Among them, the second direction B intersects the first direction A. Exemplarily, the second direction B can be perpendicular to the first direction A.

[0061] Step 103: Irradiate the area where the solder joint 11 is located by laser to weld the connection line 20 to the surface of the battery cell 10.

[0062] Specifically, the area where the solder joint 11 is located can be irradiated with a laser to weld the connection line 20 to the solder joint 11, so that the connection line 20 is electrically connected to the fine grid line 12 through the solder joint 11.

[0063] Among them, the connection line 20 in the embodiment of the present application may include a connection line substrate 21 and a bonding layer 22 coated on the connection line substrate 21. Exemplarily, the connection line substrate 21 may be a copper wire, and the bonding layer 22 may be one of a tin-lead layer, a tin-lead-bismuth layer, and a tin-bismuth layer.

[0064] In the embodiment of the present application, the area where the solder joint 11 is located can be irradiated with a laser to fuse the bonding layer 22 of the connection line 20 with the solder joint 11 to form a laser welding area 30, thereby welding the connection line 20 to the solder joint 11 and enabling the connection line 20 to be electrically connected to the fine grid line 12 through the solder joint 11.

[0065] It should be noted that in the embodiment of the present application, the instantaneous temperature of the area where the solder joint 11 is irradiated with a laser is greater than or equal to 135 degrees and less than or equal to 185 degrees. Exemplarily, the instantaneous temperature of the area where the solder joint 11 is irradiated with a laser can be 135 degrees, 145 degrees, 155 degrees, 165 degrees, 175 degrees, 185 degrees, etc. In this regard, the embodiment of the present application does not make specific limitations, and in actual applications, those skilled in the art can set it as needed.

[0066] The method for preparing a photovoltaic module disclosed in the embodiment of the present application welds the connection line 20 to the surface of the battery cell 10 by irradiating the area where the solder joint 11 is located with a laser. By using the method for preparing a photovoltaic module disclosed in the embodiment of the present application to prepare a photovoltaic module, the connection line 20 is not prone to thermal expansion and contraction, and the process yield of the photovoltaic module is relatively high.

[0067] As Figure 2 shown, a method for preparing a photovoltaic module according to another embodiment of the present application is shown, and the method includes:

[0068] Step 201, providing a battery cell 10, on the surface of the battery cell 10, at least two solder joints 11 and a plurality of fine grid lines 12 extending along a first direction A are provided, the plurality of fine grid lines 12 are arranged at intervals along a second direction B, the at least two solder joints 11 are arranged at intervals along the second direction B, and the projection of each solder joint 11 on the battery cell 10 at least partially overlaps the projection of one fine grid line 12 on the battery cell 10.

[0069] On the surface of the cell 10 in the embodiment of the present application, a plurality of fine grid lines 12 extending along the first direction A and spaced apart along the second direction B are provided to collect the current generated in different regions of the cell 10 through the plurality of fine grid lines 12. Moreover, at least two solder joints 11 are also provided on the surface of the cell 10. The at least two solder joints 11 are spaced apart along the second direction B, and the projection of each solder joint 11 on the cell 10 at least partially overlaps the projection of one fine grid line 11 on the cell 10.

[0070] Step 202: Provide a connection line 20, lay the connection line 20 on the surface of the cell 10 along the second direction B, so that the connection line 20 at least partially covers the solder joints 11, wherein the connection line 20 includes a connection line matrix 21 and a bonding layer 11 coated on the connection line matrix 21.

[0071] In the embodiment of the present application, the connection line 20 can be laid on the surface of the cell 10 along the second direction B, so that the connection line 20 covers at least two solder joints 11. Among them, the second direction B intersects the first direction A. Exemplarily, the second direction B can be perpendicular to the first direction A.

[0072] Step 203: Identify at least two solder joints 11 to plan the illumination path of the laser.

[0073] As Figure 4 and Figure 5 shown, the laser welding device 40 in the embodiment of the present application includes a laser, a laser head 41, a CCD camera 42, a shutter 43 and an optical fiber 44. Among them, a beam shaper is installed in the laser, and the beam shaper is connected to the shutter 43 through the optical fiber 44. The laser head 41 is connected to the shutter 43 through the optical fiber 44. A galvanometer is provided in the laser head 41. After the laser emits laser light, the scattered light beam can be integrated into a focused light beam through the beam shaper, and the focused light beam is transmitted to the laser head 41 through the optical fiber 44. The laser head 41 uses the galvanometer to change the irradiation angle of the focused light beam, so that the solder joints 11 on one cell 10 can be welded through a single optical path. The CCD camera 42 is electrically connected to the laser.

[0074] In the embodiment of the present application, the CCD camera 42 can be arranged above the cell 10 to take pictures of the cell 10 through the CCD camera 42. The taken pictures by the CCD camera 42 are transmitted to the laser, and the laser identifies the solder joints 11 on the surface of the cell 10 and plans the starting irradiation area to the ending irradiation area of the laser, so as to form the illumination path of the laser.

[0075] Step 204: Control the laser to run along the illumination path, and irradiate at least two solder joints 11 respectively through the laser to weld the connection line 20 to at least two solder joints 11.

[0076] After planning the illumination path of the laser, the galvanometer in the laser head 41 can be controlled by the laser to swing, so as to change the emission angle of the focused light along the illumination path, so that the focused light irradiates the areas where at least two solder joints 11 are located respectively, so as to weld the connecting wire 20 to the solder joints 11, so that the connecting wire 20 is electrically connected to the fine grid line 12 through the solder joints 11, and thus the current generated by the fine grid line 12 can be collected through the connecting wire 20.

[0077] It should be noted that in the embodiment of the present application, the wavelength of the laser emitted by the laser is 10 nm to 1080 nm, the average power of the laser is 10 W to 2000 W, and the laser performs laser heating welding along the illumination path at a uniform speed with a laser emission time of 5 ms / cm to 30 ms / cm. Exemplarily, the laser performs laser heating welding along the illumination path at a uniform speed with a laser emission time of 10 ms / cm.

[0078] As Figure 3 shown, a preparation method of a photovoltaic module according to another embodiment of the present application is shown, and the method includes:

[0079] Step 301: Provide a battery chip 10, on the surface of which at least two solder joints 11 and a plurality of fine grid lines 12 extending along the first direction A are arranged. The plurality of fine grid lines 12 are arranged at intervals along the second direction B, and the at least two solder joints 11 are arranged at intervals along the second direction B. The projection of each solder joint 11 on the battery chip 10 at least partially overlaps the projection of one fine grid line 12 on the battery chip 10.

[0080] Step 301 in the embodiment of the present application is the same as step 201 in the above embodiment, and will not be described in detail here.

[0081] Step 302: Provide a connecting wire 20, lay the connecting wire 20 on the surface of the battery chip 10 along the second direction B, so that the connecting wire 20 at least partially covers the solder joints 11, wherein the connecting wire 20 includes a connecting wire matrix 21 and a bonding layer 22 coated on the connecting wire matrix 21.

[0082] Step 302 in the embodiment of the present application is the same as step 202 in the above embodiment, and will not be described in detail here.

[0083] Step 303: The laser includes at least two laser beams. Identify the positions of the at least two solder joints 11, and move the at least two laser beams so that each laser beam is oppositely arranged with a solder joint 11.

[0084] The laser welding device 40 in the embodiment of the present application includes a laser, at least two laser heads 41, a CCD camera 42, a shutter 43, and an optical fiber 44. Among them, a beam shaper is installed in the laser, and the beam shaper is connected to the shutter 43 through the optical fiber 44. Each laser head 41 is connected to the shutter 43 through a corresponding optical fiber 44. After the laser emits laser light, the scattered light beams can be integrated into convergent light by the beam shaper, and the convergent light is transmitted to the shutter 43 through the optical fiber 44, and the shutter 43 divides the convergent light into at least two beams. Each beam of convergent light is transmitted to the corresponding laser head 41 through the corresponding optical fiber 44. The CCD camera 42 is electrically connected to the laser.

[0085] It should be noted that the laser welding device 40 in the embodiment of the present application includes at least two laser heads 41. Each laser head 41 is connected to the shutter 43 through an optical fiber 44. Specifically, the number of laser heads 41 is the same as the number of solder joints 11, and each laser head 41 is correspondingly arranged with a solder joint 11, so that the convergent light in each laser head 41 is correspondingly arranged with a solder joint 11.

[0086] In the embodiment of the present application, the CCD camera 42 can be arranged above the battery cell 10 to take pictures of the battery cell 10 through the CCD camera 42. The pictures taken by the CCD camera 42 are transmitted to the laser, and the laser identifies the positions of the solder joints 11 on the surface of the battery cell 10 and moves at least two laser heads 41 so that each laser head 41 is oppositely arranged with a solder joint 11, so that each laser beam is oppositely arranged with a solder joint.

[0087] Step 304, irradiate the area where the corresponding solder joint 11 is located through each laser beam to weld the connecting wire 20 to the solder joint 11.

[0088] In the embodiment of the present application, the connecting wire 20 is welded to the solder joint 11 by irradiating the area where the corresponding solder joint 11 is located through the laser beam emitted by each laser head 41, so that the connecting wire 20 is electrically connected to the fine grid line 12 through the solder joint 11, and the current collected by the fine grid line 12 is collected through the connecting wire 20.

[0089] It should be noted that in the embodiment of the present application, the wavelength of the laser emitted by each laser head 41 is 10 nm to 1080 nm. The average power of the laser is 10 W to 2000 W. The laser emission time of the laser is 5 ms to 20 ms. Specifically, the laser emission time of the laser is 10 ms.

[0090] Exemplarily, when the laser is violet light, the wavelength range is 10 nm to 400 nm. When the laser is blue light or green light, the wavelength range is 400 nm to 700 nm, preferably 532 nm. When the laser is red light, the wavelength range is 1060 nm to 1080 nm, preferably 1064 nm.

[0091] As shown Figure 8 in the figure, in the embodiment of the present application, along the direction perpendicular to the plane where the battery cell 10 is located, the projection of the laser welding area 30 on the battery cell 10 falls within the projection of the solder joint 11 on the battery cell 10, and the area of the laser welding area 30 accounts for 10% to 70% of the area of the solder joint 11.

[0092] As shown Figure 8 in the figure, along the direction perpendicular to the plane where the battery cell 10 is located, the projection of the laser welding area 30 on the battery cell 10 falls within the projection of the solder joint 11 on the battery cell 10. To avoid direct irradiation of the converged light onto the surface of the battery cell 10 during the laser welding process, resulting in damage to the battery cell 10.

[0093] Moreover, in the embodiment of the present application, the area of the laser welding area 30 is set to account for 10% to 70% of the area of the solder joint 11. The internal stress after welding the solder joint 11 and the connecting wire 20 decreases as the area of the laser welding area 30 increases. Therefore, the larger the area of the laser welding area 30, the stronger the welding between the connecting wire 20 and the solder joint 11. However, when the laser welding area 30 appears at the edge of the solder joint 11, due to precision errors, when the converged light irradiates the solder joint 11, it may irradiate onto the battery cell 10. To avoid the converged light irradiating onto the battery cell 10 and causing damage to the battery cell 10. In the embodiment of the present application, the area of the laser welding area 30 is set to account for 10% to 70% of the area of the solder joint 11.

[0094] Exemplarily, in the case where the solder joint 11 is a rectangular solder joint, when the size of the solder joint 11 is 0.6mm * 0.8mm, the area of the laser welding area 30 can be set to 0.2mm 2 , and the area of the laser welding area 30 accounts for 25% of the area of the solder joint 11. When the size of the solder joint 11 is 0.8mm * 1mm, the area of the laser welding area 30 can be set to 0.28mm 2 , and the area of the laser welding area 30 accounts for 35% of the area of the solder joint 11. When the size of the solder joint 11 is 1mm * 1.2mm, the area of the laser welding area 30 can be set to 0.35mm 2 , and the area of the laser welding area 30 accounts for 65% of the area of the solder joint 11. When the size of the solder joint 11 is 1.2mm * 1.4mm, the area of the laser welding area 30 can be set to 1.13mm 2 , and the area of the laser welding area 30 accounts for 67% of the area of the solder joint 11.

[0095] It should be noted that in the embodiments of the present application, before providing the solar cell 10, the solar cell 10 needs to be subjected to PL detection to detect the solar cell 10 with internal defects. After welding the connection line 20 to the surface of the solar cell 10 to form a battery string, the battery string needs to be subjected to EL test to detect the battery string with defects such as hidden cracks, fragments, and poor soldering.

[0096] Referring to Figure 6 , a top view of the battery string described in the embodiments of the present application is shown; referring to Figure 7 , a cross-sectional view of the battery string described in the embodiments of the present application is shown; referring to Figure 8 , a schematic structural view of the solder joint described in the embodiments of the present application is shown.

[0097] Next, the battery string disclosed in the present application will be described in detail through specific embodiments with reference to the drawings.

[0098] As Figure 6 shown, the embodiments of the present application disclose a battery string, which includes: a solar cell 10, and a solder joint 11 is provided on the surface of the solar cell 10; a connection line 20, the connection line 20 is laid on the surface of the solar cell 10 and at least partially covers the solder joint 11, and at the position where the solder joint 11 is located, the connection line 20 is welded to the surface of the solar cell 10 by laser welding.

[0099] The battery string disclosed in the embodiments of the present application includes a solar cell 10 and a connection line 20. Among them, the solar cell 10 is the core component of the photovoltaic module, and it can convert solar energy into electrical energy. A solder joint 11 is provided on the surface of the solar cell 10, and the position where the solder joint 11 is located is the position where the connection line 20 is welded to the surface of the solar cell 10.

[0100] In the embodiments of the present application, the connection line 20 is laid on the surface of the solar cell 10 and covers the solder joint 11. Then, by laser welding, at the position where the solder joint 11 is located, the connection line 20 is welded to the surface of the solar cell 10. Thus, the connection line 20 is welded to the surface of the solar cell 10 by laser welding. So that during the preparation process of the photovoltaic module, the connection line 20 is not easily thermally expanded and contracted, and the process yield of the photovoltaic module is relatively high.

[0101] It should be noted that the connection line 20 in the embodiments of the present application has electrical conductivity. It can collect the current collected by the fine grid line 12. Specifically, the connection line 20 can be a solder tape or a welding wire. In the embodiments of the present application, there is no excessive limitation on the specific type of the connection line 20. In actual use, those skilled in the art can select according to needs.

[0102] Specifically, as Figure 6As shown in the figure, in the embodiment of the present application, at least one fine grid line 12 extending along the first direction A can be provided on the surface of the battery cell 10, and at least part of the projection of the solder joint 11 on the battery cell 10 overlaps with the projection of the fine grid line 12 on the battery cell 10; the connection line 20 extends along the second direction B, and at the position where the solder joint 11 is located, the connection line 20 is welded to the solder joint 11 by laser welding, so that the connection line 20 is electrically connected to the fine grid line 12 through the solder joint 11 to collect the current collected by the fine grid line 12. Wherein, the second direction B intersects the first direction A.

[0103] As Figure 6 shown in the figure, at least one fine grid line 12 extending along the first direction A is provided on the surface of the battery cell 10 in the embodiment of the present application to collect the current generated by the battery cell 10 through the fine grid line 12. Wherein, at least part of the projection of the solder joint 11 on the battery cell 10 overlaps with the projection of the fine grid line 12 on the battery cell 10.

[0104] In the embodiment of the present application, the connection line 20 is laid on the surface of the battery cell 10 along the second direction B, so that the connection line 20 extends along the second direction B and covers the solder joint 11. Then, by means of laser welding, at the position where the solder joint 11 is located, the connection line 20 is welded to the surface of the battery cell 10. Thus, the connection line 20 can be welded to the solder joint 11 by laser welding, so that the connection line 20 is electrically connected to the fine grid line 12 through the solder joint 11 to collect the current generated by the fine grid line 12 through the connection line 20. Further, in the process of manufacturing the battery string disclosed in the present application, the connection line 20 is not easily thermally expanded and contracted, and the manufacturing yield of the battery string is relatively high.

[0105] As Figure 7 shown in the figure, the connection line 20 in the embodiment of the present application includes a connection line base body 21 and a bonding layer 22 coated on the connection line base body 21. The bonding layer 22 melts with the solder joint 11 to form a laser welding area 30, and the connection line 20 is welded to the solder joint 11 through the laser welding area 30.

[0106] The connection line 20 in the embodiment of the present application includes a connection line base body 21 and a bonding layer 22 coated on the connection line base body 21. Exemplarily, the connection line base body 21 can be a copper wire, and the bonding layer 22 can be one of a tin-lead layer, a tin-lead-bismuth layer, and a tin-bismuth layer.

[0107] As Figure 7 shown in the figure, during the laser welding process, the bonding layer 22 melts and forms a laser welding area 30 with the solder joint 11. The connection line 20 is welded to the solder joint 11 through the laser welding area 30, so that the connection line 20 is electrically connected to the fine grid line 12 through the solder joint 11 to improve the connection reliability between the connection line 20 and the battery cell 10.

[0108] It can be understood that in the embodiment of the present application, the laser welding area 30 is irradiated by a laser to melt the bonding layer 22, so as to be bonded to the solder joint 11 to form the laser welding area 30. Therefore, the laser welding area 30 in the embodiment of the present application includes the fusion area of the bonding layer 22 and the solder joint 11.

[0109] It should be noted that in the embodiment of the present application, along the direction perpendicular to the plane where the battery cell 10 is located, the height of the solder joint 11 is greater than or equal to 0.006 mm and less than or equal to 0.015 mm. Exemplarily, the height of the solder joint 11 can be 0.006 mm, 0.009 mm, 0.012 mm, 0.015 mm. The height of the laser welding area 30 is also greater than or equal to 0.006 mm and less than or equal to 0.015 mm. Exemplarily, the height of the laser welding area 30 can be 0.006 mm, 0.009 mm, 0.012 mm, 0.015 mm.

[0110] Optionally, along the direction perpendicular to the plane where the battery cell 10 is located, the shape of the laser welding area 30 includes at least one of a circle, a triangle, a square, and a rectangle; and the projection of the laser welding area 30 on the battery cell 10 falls within the projection of the solder joint 11 on the battery cell 10.

[0111] As Figure 8 shown, along the direction perpendicular to the plane where the battery cell 10 is located, the projection of the laser welding area 30 on the battery cell 10 falls within the projection of the solder joint 11 on the battery cell 10. To avoid the aggregated light directly irradiating the surface of the battery cell 10 during the laser welding process, resulting in damage to the battery cell 10.

[0112] It should be noted that in the embodiment of the present application, along the direction perpendicular to the plane where the battery cell 10 is located, the shape of the laser welding area 30 can be set to a circle, a triangle, a square, a rectangle, etc.

[0113] Along the direction perpendicular to the plane where the battery cell 10 is located, the shape of the solder joint 11 can also be set to a circle, a triangle, a square, a rectangle, etc. In the embodiment of the present application, the shapes of the laser welding area 30 and the solder joint 11 are not specifically limited, and in actual applications, those skilled in the art can set them as needed.

[0114] Exemplarily, as Figure 10As shown, the solder joint 11 can be set as a special-shaped solder joint. The special-shaped solder joint includes a rectangular structure, a first protrusion, and a second protrusion. The rectangular structure includes a first side and a second side that are oppositely arranged along the first direction A. The first protrusion is connected to the first side, and the second protrusion is connected to the second side. Through the solder joint 11 with such a special-shaped structure, the connection line 20 can be more reliably connected to the fine grid line 12. Optionally, along the direction perpendicular to the plane where the battery cell 10 is located, the area of the laser welding area 30 accounts for 10% to 70% of the area of the solder joint 11.

[0115] In the embodiment of the present application, the area of the laser welding area 30 is set to account for 10% to 70% of the area of the solder joint 11. The internal stress after the solder joint 11 and the connection line 20 are welded decreases as the area of the laser welding area 30 increases. Therefore, the larger the area of the laser welding area 30, the firmer the welding between the connection line 20 and the solder joint 11. However, when the laser welding area 30 appears at the edge of the solder joint 11, due to the precision error, when the focused light irradiates the solder joint 11, it may irradiate onto the battery cell 10. To avoid the focused light irradiating onto the battery cell 10 and causing damage to the battery cell 10. In the embodiment of the present application, the area of the laser welding area 30 is set to account for 10% to 70% of the area of the solder joint 11.

[0116] Optionally, as Figure 6 and Figure 8 shown, along the first direction A, the width of the solder joint 11 is greater than the width of the connection line 20; along the second direction B, the length of the solder joint 11 is greater than the width of the fine grid line 12.

[0117] As Figure 6 and Figure 8 shown, in the embodiment of the present application, along the first direction A, the width of the solder joint 11 is set to be greater than the width of the connection line 20. And, along the second direction B, the length of the solder joint 11 is set to be greater than the width of the fine grid line 12. To further improve the reliability of the connection between the connection line 20 and the fine grid line 12.

[0118] Optionally, as Figure 6 shown, the fine grid line 12 includes multiple ones, and the multiple fine grid lines 12 are arranged at intervals along the second direction B. The solder joint 11 includes at least two, and the at least two solder joints 11 are arranged at intervals along the second direction B. The projection of each solder joint 11 on the battery cell 10 at least partially overlaps with the projection of one fine grid line 11 on the battery cell 10; wherein, at the positions where the at least two solder joints 11 are located, the connection line 20 is welded to the corresponding solder joint 11 by laser welding.

[0119] As Figure 6As shown in the figure, a plurality of fine grid lines 12 are arranged on the surface of the battery cell 10 in the embodiment of the present application. The plurality of fine grid lines 12 all extend along the first direction A and are arranged at intervals along the second direction B. The current generated in different regions of the battery cell 10 is collected by the plurality of fine grid lines 12.

[0120] In the embodiment of the present application, at least two solder joints 11 are further arranged on the surface of the battery cell 10. The at least two solder joints 11 are arranged at intervals along the second direction B, and the projection of each solder joint 11 on the battery cell 10 at least partially overlaps with the projection of one fine grid line 12 on the battery cell 10.

[0121] In the embodiment of the present application, the connection line 20 is laid on the surface of the battery cell 10 along the second direction B, so that the connection line 20 extends along the second direction and covers at least two solder joints 11. Then, by means of laser welding, the connection line 20 is welded to the solder joints 11 at the positions where the at least two solder joints 11 are located. Thus, the connection line 20 is electrically connected to the fine grid line 12 through the solder joints 11, so as to collect the current generated by the plurality of fine grid lines 12 through the connection line 20. Further, in the process of manufacturing the battery string disclosed in the present application, the connection line 20 is not prone to thermal expansion and contraction, and the manufacturing yield of the battery string is relatively high.

[0122] Optionally, the number of the solder joints 11 is 2 to 8, and the 2 to 8 solder joints 11 are arranged at intervals along the second direction B.

[0123] When the connection line 20 is welded to the battery cell 10, if there are many solder joints 11 between the connection line 20 and the battery cell 10, the solder joints 11 will block the battery cell 11, thereby affecting the photoelectric conversion efficiency of the battery cell 10. Therefore, in the embodiment of the present application, the number of the solder joints 11 is set to 2 to 8, so as to weld the connection line 20 to the surface of the battery cell 10 through the solder joints 11, and at the same time, avoid the influence of too many solder joints 11 on the photoelectric conversion efficiency of the battery cell 10.

[0124] Exemplarily, in the embodiment of the present application, the number of the solder joints 11 can be set to 2, 3, 4, 5, 6, 7, 8.

[0125] Preferably, the solder joints 11 can include 5 or 6, and the 5 or 6 solder joints 11 are arranged at intervals along the second direction B.

[0126] When only two solder joints 11 are provided between the connection line 20 and the solar cell 10, one solder joint 11 can be arranged at the head end of the connection line 20, and the other solder joint 11 can be arranged at the tail end of the connection line 20. During the lamination process of the photovoltaic module, since the lamination requires evacuating the photovoltaic module, evacuating is likely to cause the connection line 20 to deform, affecting the appearance of the photovoltaic module. Therefore, in the embodiments of the present application, the number of solder joints 11 is set to 5 or 6 to improve the appearance of the photovoltaic module while ensuring the photoelectric conversion efficiency of the solar cell 10.

[0127] Optionally, as Figure 5 shown, the solar cell 10 includes a first surface and a second surface arranged opposite to each other. A first solder joint is provided on the first surface, and a second solder joint is provided on the second surface; the connection line 20 includes a first connection line and a second connection line. The first connection line is laid on the first surface and at least partially covers the first solder joint. At the position where the first solder joint is located, the first connection line is welded to the first surface by laser welding; the second connection line is laid on the second surface and at least partially covers the second solder joint. At the position where the second solder joint is located, the second connection line is welded to the second surface by laser welding.

[0128] As Figure 5 shown, in the embodiments of the present application, the first connection line can be welded to the first solder joint on the first surface of the solar cell 10 by laser welding. At the same time, the second connection line can be welded to the second solder joint on the second surface of the solar cell 10 by laser welding.

[0129] It should be noted that in the battery string, there are usually multiple solar cells 10. The multiple solar cells 10 are arranged at intervals. One end of the connection line 20 is welded to the surface of one solar cell 10, and the other end of the connection line 20 is welded to the surface of another adjacent solar cell 10, so as to connect the multiple solar cells 10 in series to form a battery string.

[0130] Referring to Figure 9 , a schematic structural diagram of the bus bar in the embodiments of the present application is shown.

[0131] Next, the photovoltaic module disclosed in the present application will be described in detail through specific embodiments with reference to the accompanying drawings.

[0132] The embodiments of the present application also disclose a photovoltaic module, which includes at least two battery strings as described in the above embodiments, and the at least two battery strings are arranged at intervals.

[0133] It should be noted that in the embodiments of the present application, the battery strings included in the photovoltaic module have the same structure as the battery strings described in the above embodiments, and their beneficial effects are also similar, which will not be elaborated here.

[0134] Optionally, the photovoltaic module further includes a bus bar 50. As shown Figure 9 in the figure, the bus bar 50 is disposed between two adjacent battery strings, or the bus bar 50 is disposed on a side of the battery string away from another adjacent battery string. The connection line 20 is extended to the surface of the bus bar 20, and the connection line 20 is welded to the surface of the bus bar 50 by laser welding, so that the current collected by the battery string can be collected through the bus bar 50.

[0135] Specifically, in the embodiment of the present application, the width of the bus bar 50 located on a side of the battery string away from another adjacent battery string can be set to 3.5 mm to 4 mm. For example, the width of the bus bar 50 located on a side of the battery string away from another adjacent battery string can be set to 3.5 mm, 3.7 mm, 4 mm, etc. The width of the bus bar 50 disposed between two adjacent battery strings is set to 5 mm to 7 mm. For example, the width of the bus bar 50 located between two adjacent battery string groups can be set to 5 mm, 6 mm, 7 mm, etc.

[0136] It should be noted that the bus bar 50 in the embodiment of the present application also includes a bus bar substrate and a bonding layer coated on the surface of the bus bar substrate. The bonding layer can also be one of a tin-lead layer, a tin-lead-bismuth layer, and a tin-bismuth alloy layer. And the thickness of the bonding layer is 0.005 mm to 0.02 mm.

[0137] In addition, in the embodiment of the present application, the projection area of the connection line 20 on the plane where the bus bar 50 is located is a welding area. Along the extending direction of the connection line 20, the length of the welding area is set to be greater than or equal to 0.1 mm and less than or equal to 7 mm. Specifically, along the extending direction of the connection line 20, the length of the welding area can be set to 0.1 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, etc. Along the length direction of the bus bar 50, the width of the welding area is set to be greater than or equal to 0.1 mm and less than or equal to 0.6 mm. Specifically, along the length direction of the bus bar 50, the width of the welding area can be set to 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, etc.

[0138] It should be noted that each embodiment in this specification is described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0139] Although alternative embodiments of the embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include alternative embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0140] Finally, it should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity from another, and do not necessarily require or imply any such actual relationship or order between these entities. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that an article or terminal device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such article or terminal device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the article or terminal device comprising the element.

[0141] The technical solutions provided by the present invention have been introduced in detail above. Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. At the same time, for those of ordinary skill in the art, according to the principles and implementation manners of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation on the present invention.

Claims

1. A method for preparing a photovoltaic module, characterized in that: The method comprises: Providing a battery cell, wherein a welding spot is arranged on a surface of the battery cell; Providing a connecting wire, and laying the connecting wire on the surface of the battery cell so that the connecting wire at least partially covers the welding point; The connecting wire is welded to the surface of the battery cell by irradiating the area where the welding point is located with a laser.

2. The method for preparing a photovoltaic module according to claim 1, characterized in that: At least one thin grid line extending along a first direction is arranged on the surface of the battery cell, and the projection of the welding point on the battery cell at least partially overlaps with the projection of the thin grid line on the battery cell; The method of laying the connecting wire on the surface of the battery cell comprises: The connecting wire is laid on the surface of the battery sheet along a second direction, and the second direction intersects with the first direction.

3. The method for preparing a photovoltaic module according to claim 1, characterized in that: The connecting wire comprises a connecting wire substrate and a bonding layer coated on the connecting wire substrate. The method of welding the connecting wire to the welding point by irradiating the welding point with a laser comprises: The welding spot is irradiated with laser so that the bonding layer of the connecting wire is fused with the welding spot to form a laser welding area, thereby welding the connecting wire to the welding spot.

4. The method for preparing a photovoltaic module according to claim 2, characterized in that: The fine grid lines include a plurality of fine grid lines, which are arranged at intervals along the second direction; the welding points include at least two, which are arranged at intervals along the second direction; and the projection of each welding point on the battery cell at least partially overlaps with the projection of one of the fine grid lines on the battery cell; The method of welding the connecting wire to the welding point by irradiating the welding point with a laser also includes: Identifying the at least two welding points to plan a light path of the laser; The laser is controlled to run along the light path, and the laser is used to irradiate the areas where the at least two welding points are located respectively, so as to weld the connecting wire to the at least two welding points.

5. The method for preparing a photovoltaic module according to claim 4, characterized in that: The laser comprises at least two laser beams; Alternatively, the method of welding the connecting wire to the welding point by irradiating the welding point with a laser further comprises: Identifying the positions of the at least two welding spots, and moving the at least two laser beams so that each of the laser beams is disposed opposite to one of the welding spots; Each laser beam irradiates the area corresponding to the welding point so as to weld the connecting wire to the welding point.

6. The method for preparing a photovoltaic module according to claim 1, characterized in that: The instantaneous temperature of the area where the welding point is located when the laser irradiates is greater than or equal to 135 degrees and less than or equal to 185 degrees.

7. The method for preparing a photovoltaic module according to claim 3, characterized in that: Along a direction perpendicular to the plane where the battery cell is located, the projection of the laser welding area on the battery cell falls within the projection of the welding point on the battery cell, and the area of ​​the laser welding area occupies 10% to 70% of the area of ​​the welding point.

8. A battery string, characterized in that: include: A battery cell, wherein a welding spot is arranged on a surface of the battery cell; A connecting wire is laid on the surface of the battery cell and at least partially covers the welding point. At the location of the welding point, the connecting wire is welded to the surface of the battery cell by laser welding.

9. The battery string according to claim 8, characterized in that: At least one thin grid line extending along a first direction is arranged on the surface of the battery cell, and the projection of the welding point on the battery cell at least partially overlaps with the projection of the thin grid line on the battery cell; The connecting wire extends along the second direction, and at the location of the welding point, the connecting wire is welded to the welding point by laser welding, so that the connecting wire is electrically connected to the fine grid line through the welding point; The second direction intersects with the first direction.

10. The battery string according to claim 9, characterized in that: The connecting wire comprises a connecting wire substrate and a bonding layer coated on the connecting wire substrate. The joining layer melts and forms a laser welding area with the welding point, and the connecting line is welded to the welding point through the laser welding area.

11. The battery string according to claim 10, characterized in that: The laser welding area includes a fusion area of ​​the bonding layer and the welding point.

12. The battery string according to claim 10, characterized in that: Along the direction perpendicular to the plane where the battery cell is located, the shape of the laser welding area includes at least one of a circle, a triangle, a square, and a rectangle; And the projection of the laser welding area on the battery cell falls within the projection of the welding point on the battery cell.

13. The battery string according to claim 11, characterized in that: Along a direction perpendicular to the plane where the battery cell is located, the area of ​​the laser welding region accounts for 10% to 70% of the area of ​​the welding point.

14. The battery string according to claim 9, characterized in that: Along the first direction, the width of the welding spot is greater than the width of the connecting line; Along the second direction, the length of the welding spot is greater than the width of the thin gate line.

15. The battery string according to claim 9, characterized in that: The fine grid lines include a plurality of them, and the plurality of the fine grid lines are arranged at intervals along the second direction; the welding points include at least two, and the at least two welding points are arranged at intervals along the second direction, and the projection of each welding point on the battery cell at least partially overlaps with the projection of one of the fine grid lines on the battery cell; Wherein, at the locations of the at least two welding points, the connecting wire is welded to the corresponding welding points by laser welding.

16. The battery string according to claim 15, characterized in that: The number of the welding spots is 2 to 8, and the 2 to 8 welding spots are arranged at intervals along the second direction.

17. The battery string according to claim 15, characterized in that: The number of the welding spots is 5 or 6, and the 5 or 6 welding spots are arranged at intervals along the second direction.

18. The battery string according to claim 10, characterized in that: The bonding layer includes one of a tin-lead layer, a tin-lead-bismuth layer, and a tin-bismuth layer.

19. The battery string according to claim 8, characterized in that: The battery cell comprises a first surface and a second surface which are arranged opposite to each other, a first welding spot is arranged on the first surface, and a second welding spot is arranged on the second surface; The connecting wires include a first connecting wire and a second connecting wire, the first connecting wire is laid on the first surface and at least partially covers the first welding point, and the first connecting wire is welded to the first surface at the location of the first welding point by laser welding; The second connecting line is laid on the second surface and at least partially covers the second welding point. The second connecting line is welded to the second surface at the location of the second welding point by laser welding.

20. A photovoltaic module, characterized in that: The method comprises at least two battery strings according to any one of claims 8 to 19, wherein the at least two battery strings are arranged at intervals.

21. The photovoltaic module according to claim 20, characterized in that: The photovoltaic assembly further includes: a bus bar, the bus bar is arranged between two adjacent battery strings, or the bus bar is arranged on a side of the battery string away from another adjacent battery string; The connecting wire extends to the surface of the bus bar and is welded to the surface of the bus bar by laser welding.

22. The photovoltaic module according to claim 21, characterized in that: The projection area of ​​the connecting line on the plane where the busbar is located is a welding area, and along the extension direction of the connecting line, the length of the welding area is greater than or equal to 0.1 mm and less than or equal to 7 mm; Along the length direction of the bus bar, the width of the welding area is greater than or equal to 0.1 mm and less than or equal to 0.6 mm.

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