Photovoltaic solder strip, battery string and photovoltaic module preparation method

Abstract

The invention discloses a photovoltaic solder strip, a battery string and a photovoltaic module preparation method, and belongs to the technical field of photovoltaic modules. The photovoltaic welding strip is characterized in that a first conductive electromagnetic attraction contact is arranged on the welding surface of a conductive base strip; the welding surface is the surface of one side, used for being welded with a grid line of a battery piece, of the conductive base band, and the first conductive magnetic attraction contacts are used for connecting the conductive base band to the surface of the battery piece in a magnetic attraction mode and enabling the conductive base band to be electrically connected with the grid line. Compared with a traditional welding mode, the magnetic attraction method adopted by the invention has the advantages that no influence is caused on the battery piece, grid breaking cannot be caused, shading or EL detection shadow cannot be caused, and the attraction force of magnetic attraction is larger than that of a film covering scheme and an adhesive dispensing scheme. Before welding, the photovoltaic welding strip is accurately fixed on the battery piece through magnetic attraction, and the bad problems of deviation, warping and the like of the welding strip under the high-temperature effect of a series welding machine in the welding process can be prevented.

Description

Technical Field

[0001] This application relates to the field of photovoltaic module technology, and in particular to a photovoltaic ribbon, a battery string, and a method for preparing a photovoltaic module. Background Technology

[0002] In the process of connecting solar cells into photovoltaic modules, welding strips are required to connect the solar cells in series or in parallel. The commonly used welding methods are: (1) Coating method: The welding strip and the solar cell are pressed together by a copper wire composite film with embedded copper welding strips, and then the welding strip and the solar cell are alloyed. (2) Dispensing method: The welding strip is cured on the solar cell by dispensing adhesive, and then the welding strip and the solar cell are alloyed. (3) Welding and dispensing method: The welding strip is first welded to the solar cell for initial fixation, and then the welding strip is further glued to the solar cell by dispensing adhesive, and then the welding strip and the solar cell are alloyed. Among them, the coating method and the dispensing method are used to fix the welding strip and the solar cell before welding. However, due to the insufficient bonding force between the welding strip and the solar cell in the two methods, the welding strip is prone to deviation and warping under the high temperature of the string welding machine during the subsequent welding process. Moreover, the coating method will also bring problems such as increased cost and optical shading; the dispensing method will have shadows under the welding strip during EL testing. While the welding and adhesive bonding method adds a welding step and enhances adhesion, the solder strip can shrink and easily break the fine grid during the initial fixation process at high temperatures. Therefore, preventing solder strip misalignment and warping during welding is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0003] The purpose of this application is to provide a method for preparing photovoltaic solder ribbons, battery strings, and photovoltaic modules, thereby preventing defects such as solder ribbon displacement and warping during the welding process.

[0004] To achieve the above objectives, this application provides a photovoltaic bonding strip, comprising: a conductive base strip; a first conductive electromagnetic attraction contact is provided on the welding surface of the conductive base strip; the welding surface is one side surface of the conductive base strip used for bonding with the grid lines of a solar cell, and the first conductive electromagnetic attraction contact is used to magnetically connect the conductive base strip to the surface of the solar cell, thereby electrically connecting the conductive base strip with the grid lines.

[0005] Optionally, the first electromagnetic attraction contact is embedded in the welding surface; the height of the surface of the first electromagnetic attraction contact near the grid line is higher than that of the welding surface.

[0006] Optionally, the conductive base strip is a flat conductive base strip; the conductive base strip includes a copper substrate and a tin layer covering the periphery of the copper substrate.

[0007] Optionally, the welding surface of the conductive base strip is provided with a plurality of first conductive electromagnetic attraction points along the extension direction of the conductive base strip; the first conductive electromagnetic attraction points are located on the centerline of the welding surface parallel to the extension direction.

[0008] To achieve the above objectives, this application also provides a battery string, comprising: a plurality of battery cells and a photovoltaic ribbon connecting adjacent battery cells, wherein the photovoltaic ribbon includes a conductive base strip, and the welding surface of the conductive base strip is provided with a first electromagnetic attraction point; the battery cell includes a substrate, and the surface of the substrate is provided with grid lines and a second electromagnetic attraction point; the second electromagnetic attraction point of the battery cell contacts the first electromagnetic attraction point of the photovoltaic ribbon, for magnetically connecting the photovoltaic ribbon to the surface of adjacent battery cells, and making the photovoltaic ribbon electrically connected to the grid lines of the battery cells.

[0009] Optionally, the second conductive magnetic attraction contact is disposed on the surface of the grid line or connected to the grid line.

[0010] Optionally, the grid line includes a main grid and a sub-grid, and the surface of the main grid is provided with a plurality of second electromagnetic attraction points along its extension direction; the second electromagnetic attraction points correspond one-to-one with the first electromagnetic attraction points of the photovoltaic ribbon.

[0011] Optionally, the second conductive magnetic attraction contact is a nickel-plated pad.

[0012] Optionally, the gate line includes a positive electrode main gate and a negative electrode main gate; both the positive electrode main gate and the negative electrode main gate are disposed on the back side of the substrate, the back side being the surface of the substrate facing away from sunlight; the positive electrode main gate and the negative electrode main gate extend along a first direction and are alternately arranged along a second direction; the positive electrode main gate is in electrical contact with a plurality of positive electrode sub-gates, and the negative electrode main gate is in electrical contact with a plurality of negative electrode sub-gates; the positive electrode sub-gates and the negative electrode sub-gates extend along the second direction and are alternately arranged along the first direction;

[0013] The positive electrode main grid surface is provided with the second electromagnetic attraction point; the negative electrode main grid surface is provided with the second electromagnetic attraction point.

[0014] To achieve the above objectives, this application also provides a method for manufacturing a photovoltaic module, comprising:

[0015] Multiple photovoltaic ribbons are magnetically connected to the first electromagnetic attraction points of multiple solar cells to form a battery string.

[0016] After the photovoltaic ribbon is magnetically pre-fixed to the battery cell, the photovoltaic ribbon is welded to obtain the welded battery string;

[0017] The photovoltaic module is prepared based on the welded battery string.

[0018] Optionally, when the solar cell is a back-contact solar cell, the step of magnetically connecting the first electromagnetic attraction points of multiple photovoltaic ribbons with the second electromagnetic attraction points of multiple solar cells to form a battery string includes:

[0019] Multiple photovoltaic ribbons are placed in ribbon placement slots on a mold; the ribbon placement slots are provided with air blowing holes inside.

[0020] After placement, multiple back-contact solar cells are placed on the mold in the solar cell placement position surrounded by solar cell limiting posts, so that the second electromagnetic attraction point of the back-contact solar cell is magnetically connected to the first electromagnetic attraction point of the photovoltaic ribbon to form the battery string.

[0021] Accordingly, the welding of the photovoltaic strips to obtain the welded battery string includes:

[0022] Hot air is blown into the air blowing hole to perform hot air welding on the photovoltaic welding strip, thereby obtaining the welded battery string.

[0023] Clearly, this application incorporates conductive magnetic attraction contacts on the photovoltaic ribbon and solar cell, securing them together via magnetic attraction. Compared to traditional coating, dispensing, or welding-dispensing methods, the magnetic attraction method offers advantages such as no impact on the solar cell, no grid breakage, no shading or EL detection shadows, and stronger magnetic attraction than coating and dispensing methods. Precisely fixing the photovoltaic ribbon to the solar cell using magnetic attraction before welding prevents issues like ribbon misalignment and warping caused by the high temperatures of the string welding machine during the welding process. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a photovoltaic welding strip provided in an embodiment of this application;

[0026] Figure 2 This is a partial schematic diagram of a photovoltaic ribbon and a solar cell after magnetic attraction, provided as an embodiment of this application.

[0027] Figure 3 This is a schematic diagram of the structure of a battery cell provided in an embodiment of this application;

[0028] Figure 4 A flowchart illustrating a photovoltaic module fabrication method provided in this application embodiment;

[0029] Figure 5 A schematic diagram of the structure of a mold provided in an embodiment of this application.

[0030] Figure 6 This is a schematic diagram of the structure of a photovoltaic module provided in an embodiment of this application.

[0031] The annotations in the attached figures are explained as follows:

[0032] 1-Photovoltaic solder ribbon; 11-First conductive electromagnetic attraction contact; 12-Copper substrate; 13-Tin layer;

[0033] 2-Solar cell; 20-Substrate; 21-Second conductive magnetic attraction contact; 22-Positive electrode main grid; 221-Positive electrode secondary grid; 23-Negative electrode main grid; 231-Negative electrode secondary grid;

[0034] 3-Mold; 31-Strip placement groove; 32-Blowout hole; 33-Cell cell limiting post; 34-Cell cell placement position;

[0035] 41-Encapsulation backplate; 42-First layer of adhesive film; 43-Battery matrix; 44-Second layer of adhesive film; 45-Front panel glass. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] The photovoltaic industry is currently highly competitive. With companies aggressively expanding production, the supply of photovoltaic modules has gradually exceeded demand. As module prices continue to fall, technological breakthroughs, process improvements, and cost reductions are essential for achieving advanced production capacity and are the ultimate goals of photovoltaic module technology advancement. Currently, grid-less back-contact cells, where all electrodes are distributed in a crisscross pattern on the back of the cell, completely eliminate optical losses on the front side and increase short-circuit current. Their significant advantages, such as the absence of grid lines and silver paste points on the front side, have made them a popular technology.

[0038] Due to the close proximity of the electrodes, precision welding is required, and the special structure will cause welding stress concentration. The commonly used welding methods for solder strips in traditional photovoltaic module processes are: (1) Coating scheme: First, an organic thin film (copper wire composite film) with embedded copper solder strips is made, and then laminated to achieve alloying between the solder strip and the cell. The biggest difference between this scheme and other schemes is that it requires a copper wire composite film. (2) Dispensing scheme: First, apply adhesive dots to cure the entire solder strip on the cell using a UV lamp, and then laminate to achieve alloying between the solder strip and the cell. The difference between this scheme and the welding dispensing scheme is that welding is not required, and dispensing can achieve fixation. (3) Welding dispensing scheme: First, the solder strip is welded to the cell, and then adhesive is dispensed to further adhere the solder strip to the cell, and then laminated to achieve alloying. The difference between this scheme and the welding dispensing scheme is that welding is required to achieve initial fixation, and dispensing is required to further fixation.

[0039] In summary, each of the three methods has its advantages and disadvantages: the welding and dispensing method adds a welding step, which enhances the bonding strength, but the fine grid is prone to breakage during the shrinkage of the solder ribbon. The coating method is unique in that it uses a copper wire composite film, which improves the bonding strength between the solder ribbon and the cell, but brings problems such as increased cost and optical obstruction. The dispensing method has a simple procedure and strong equipment stability, but there is shadow under the solder ribbon during EL testing, and the bonding strength between the solder ribbon and the cell is insufficient. In addition, both the coating and dispensing methods fix the solder ribbon and the cell before welding, but due to the insufficient bonding strength between the solder ribbon and the cell in both methods, the solder ribbon is prone to misalignment and warping during subsequent welding. These problems will further lead to cell warping, increased breakage rate, and poor soldering. These defects will result in slow production cycle and low production efficiency in the workshop, becoming one of the bottlenecks for the large-scale development of back contact technology.

[0040] Therefore, this application provides a method for manufacturing photovoltaic ribbons, cell strings, and photovoltaic modules. Conductive electromagnetic attraction contacts are set on the photovoltaic ribbons and cell sheets, and the photovoltaic ribbons and cell sheets are fixed by magnetic attraction. Precisely fixing the photovoltaic ribbons to the cell sheets via magnetic attraction before welding prevents defects such as ribbon misalignment and warping caused by the high temperature of the string welding machine during the welding process. This simplifies the process flow, improves process yield, reduces production costs, and solves bottleneck problems.

[0041] The photovoltaic welding strip provided in this application embodiment may include: a conductive base strip; the welding surface of the conductive base strip is provided with a first conductive electromagnetic attraction contact 11; the welding surface is the side surface of the conductive base strip used for welding with the grid lines of the solar cell 2, and the first conductive electromagnetic attraction contact 11 is used to magnetically connect the conductive base strip to the surface of the solar cell 2, so that the conductive base strip is electrically connected to the grid lines.

[0042] This embodiment does not limit the specific type of conductive baseband, as long as it is conductive enough to ensure electrical connection with the grid lines. For example, the conductive baseband may include a copper substrate 12 and a tin layer 13 covering the outer periphery of the copper substrate 12. It should be noted that the tin layer 13 coated on the surface of the copper substrate 12 can be achieved through special processes such as electroplating, vacuum deposition, spraying, or hot-dip coating. During the coating process, it is difficult to guarantee that the thickness of the tin layer 13 is completely uniformly covered on the copper substrate 12; generally, it is sufficient to ensure that the average thickness of the tin layer 13 on the copper substrate 12 meets the standard. The specific average thickness of the tin layer 13 can be determined based on the actual selected copper substrate 12 and the coating method. This embodiment does not limit the specific shape of the conductive baseband, and it may include, but is not limited to, a flat conductive baseband; the width of the flat conductive baseband can be 0.2mm to 0.3mm, including the values ​​at both ends. This embodiment does not limit the specific type of the battery cell 2, and it may include, but is not limited to, a back contact battery cell 2.

[0043] This embodiment does not limit the specific type of the first conductive magnetic contact 11. Any conductive magnetic material can be used, as long as it ensures that when the first conductive magnetic contact 11 contacts the second conductive magnetic contact 21, magnetic and electrical connections between the photovoltaic ribbon 1 and the solar cell 2 can be achieved. This embodiment does not limit the specific shape of the first conductive magnetic contact 11, and it can be, but is not limited to, a cylindrical conductive magnetic contact. The diameter of the cylindrical conductive magnetic contact can be 0.1mm to 0.15mm, including the values ​​at both ends; the height of the cylindrical conductive magnetic contact can be 0.5mm to 0.8mm, including the values ​​at both ends.

[0044] This embodiment does not limit the specific connection method between the first electromagnetic absorbing contact 11 and the conductive baseband. For example, the first electromagnetic absorbing contact 11 can be embedded in the soldering surface; the first electromagnetic absorbing contact 11 can also be directly fixed to the soldering surface without embedding. It should be noted that when the first electromagnetic absorbing contact 11 is embedded in the soldering surface, in order to better connect the solder strip to the battery cell 2, the height of the surface of the first electromagnetic absorbing contact 11 near the grid line can be higher than the soldering surface. In addition, it should be noted that when the conductive baseband includes a copper substrate 12 and a tin layer 13 covering the copper substrate 12, the first electromagnetic absorbing contact 11 can be embedded in the copper substrate 12 from the soldering surface.

[0045] Furthermore, in order to achieve more precise fixation of the photovoltaic ribbon 1 and the solar cell 2, while avoiding uneven suction that could cause the solar cell 2 to break, such as... Figure 1 As shown in this embodiment, the welding surface of the conductive base strip can be provided with multiple first conductive electromagnetic attraction points 11 along the extension direction of the conductive base strip. For example... Figure 2As shown, the first electromagnetic attraction point 11 on the photovoltaic ribbon 1 corresponds to the second electromagnetic attraction point 21 on the solar cell 2, achieving precise docking between the photovoltaic ribbon 1 and the solar cell 2. This embodiment does not limit the specific spacing between adjacent first electromagnetic attraction points 11, as long as the specific spacing between adjacent first electromagnetic attraction points 11 matches the specific interval between adjacent second electromagnetic attraction points 21, to ensure that the first electromagnetic attraction points 11 and the second electromagnetic attraction points 21 can be magnetically connected one-to-one. Furthermore, to better connect the ribbon and the solar cell 2, in this embodiment, the first electromagnetic attraction point 11 can be located on the centerline of the welding surface parallel to the extension direction.

[0046] Based on the above embodiments, this application provides conductive electromagnetic attraction contacts on the photovoltaic ribbon 1 and the solar cell 2, fixing the photovoltaic ribbon 1 and the solar cell 2 by magnetic attraction. Compared with traditional coating, dispensing, or welding dispensing methods, the magnetic attraction method has the advantage of having no impact on the solar cell 2, not causing grid breakage, not causing shading or EL detection shadows, and the magnetic attraction force is greater than that of coating and dispensing methods. Precisely fixing the photovoltaic ribbon 1 to the solar cell 2 by magnetic attraction before welding can prevent problems such as ribbon misalignment and warping due to the high temperature of the string welding machine during welding.

[0047] The battery string provided in this application embodiment may include: a plurality of battery cells 2 and a photovoltaic ribbon 1 connecting adjacent battery cells 2. The photovoltaic ribbon 1 includes a conductive base strip, and the welding surface of the conductive base strip is provided with a first electromagnetic attraction point 11. The battery cell 2 includes a substrate 20, and the surface of the substrate 20 is provided with grid lines and a second electromagnetic attraction point 21. The second electromagnetic attraction point 21 of the battery cell 2 contacts the first electromagnetic attraction point 11 of the photovoltaic ribbon 1, for magnetically connecting the photovoltaic ribbon 1 to the surface of the adjacent battery cell 2, and making the photovoltaic ribbon 1 electrically connected to the grid lines of the battery cell 2.

[0048] This embodiment does not limit the specific type of substrate 20, which may include, but is not limited to, silicon wafers.

[0049] This embodiment does not limit the specific location of the second conductive electromagnetic contact point. For example, it can be set on the surface of the grid line or connected to the grid line. It should be noted that when the surface of the battery cell 2 has a main grid and a sub-grid, the second conductive electromagnetic contact point 21 can be directly set on the surface of the main grid; when the battery cell 2 has a sub-grid but no main grid, the second conductive electromagnetic contact point 21 can be set between adjacent sub-grids.

[0050] This embodiment does not limit the specific type of the second electromagnetic attraction contact 21, as long as it ensures that when the first electromagnetic attraction contact 11 and the second electromagnetic attraction contact 21 are in contact, magnetic and electrical connections between the photovoltaic ribbon 1 and the solar cell 2 can be achieved. For example, the second electromagnetic attraction contact 21 can be a nickel-plated pad. A nickel layer is directly plated on the surface of the pad, and the nickel layer can attract the electromagnetic attraction contact in the photovoltaic ribbon 1, reducing costs and solving welding problems. This embodiment does not limit the specific shape of the second electromagnetic attraction contact 21, and it can include, but is not limited to, a square electromagnetic attraction contact; the side length of the square electromagnetic attraction contact can be 0.1mm to 0.2mm, including the values ​​at both ends.

[0051] Furthermore, to achieve more precise fixation of the photovoltaic ribbon 1 and the solar cell 2, and to avoid uneven attraction leading to breakage of the solar cell 2, the grid lines in this embodiment may include a main grid and a sub-grid. Multiple second electromagnetic attraction points 21 are provided on the surface of the main grid along its extension direction. Each second electromagnetic attraction point 21 corresponds one-to-one with a first electromagnetic attraction point 11 of the photovoltaic ribbon 1. This embodiment does not limit the specific spacing between adjacent second electromagnetic attraction points 21, as long as the specific spacing between adjacent second electromagnetic attraction points 21 matches the specific interval of adjacent first electromagnetic attraction points 11, to ensure that the first electromagnetic attraction points 11 and the second electromagnetic attraction points 21 can be magnetically connected one-to-one.

[0052] This embodiment does not limit the specific structure of the grid lines. The grid line structure varies depending on the type of battery cell. For example, in a back-contact battery, both the positive and negative electrode grid lines are distributed on the back side of the substrate 20, which is the surface of the substrate 20 facing away from sunlight. In an emitter-back passivated battery, the positive and negative electrode grid lines are distributed on the front and back sides of the substrate 20, respectively. Furthermore, to improve the efficiency of carrier collection, such as... Figure 3 In this embodiment, the gate lines may include a positive electrode main gate 22 and a negative electrode main gate 23; both the positive electrode main gate 22 and the negative electrode main gate 23 are disposed on the back side of the substrate 20; the positive electrode main gate 22 and the negative electrode main gate 23 extend along a first direction and are alternately arranged along a second direction; a positive electrode sub-gate 221 is disposed on the positive electrode main gate 22, and a negative electrode sub-gate 231 is disposed on the negative electrode main gate 23; the positive electrode sub-gate 221 and the negative electrode sub-gate 231 extend along the second direction and are alternately arranged along the first direction; a second conductive electromagnetic attraction point 21 is disposed on the surface of the positive electrode main gate 22; a second conductive electromagnetic attraction point 21 is disposed on the surface of the negative electrode main gate 23.

[0053] Based on the above embodiments, this application provides conductive electromagnetic attraction contacts on the photovoltaic ribbon and the solar cell, fixing the photovoltaic ribbon and the solar cell by magnetic attraction. Compared with traditional coating, dispensing, or welding-dispensing methods, the magnetic attraction method has the advantages of having no impact on the solar cell, not causing grid breakage, not causing shading or EL detection shadows, and the magnetic attraction force is greater than that of coating and dispensing methods. Precisely fixing the photovoltaic ribbon to the solar cell by magnetic attraction before welding can prevent problems such as ribbon displacement and warping caused by the high temperature of the string welding machine during the welding process.

[0054] Please refer to Figure 4 , Figure 4 A flowchart of a photovoltaic module fabrication method provided in this application embodiment, the method may include:

[0055] S101: The first electromagnetic attraction point of multiple photovoltaic ribbons is magnetically connected to the second electromagnetic attraction point of multiple solar cells to form a battery string.

[0056] This embodiment does not limit the specific method of forming the battery string; the specific method of forming the battery string is determined according to the specific type of battery cell 2.

[0057] Please refer to Figure 5 , Figure 5 This is a schematic diagram of the structure of a mold 3 provided in an embodiment of this application. In this embodiment, when the battery cell 2 is in back contact with the battery cell 2, step S101 may include:

[0058] Multiple photovoltaic welding ribbons 1 are placed in the welding ribbon placement groove 31 on the mold 3; the inside of the welding ribbon placement groove 31 is provided with air blowing holes 32;

[0059] After placement, multiple back-contact solar cells 2 are placed on the mold 3 and the solar cell placement position 34 formed by the solar cell limiting post 33 is formed, so that the second electromagnetic attraction point 21 of the back-contact solar cell 2 is magnetically connected to the first electromagnetic attraction point 11 of the photovoltaic welding ribbon 1 to form a battery string.

[0060] Accordingly, step S102 may include:

[0061] Hot air is blown into the air vent 32 to perform hot air welding on the photovoltaic welding strip 1, resulting in a welded battery string.

[0062] It should be noted that this embodiment uses mold 3 for integral heating, achieving integrated welding of the battery string, which simplifies the process. Furthermore, the battery cells 2 are heated uniformly throughout, effectively reducing their warpage and improving yield. This embodiment uses a magnetic method to fix the solder ribbon before welding, eliminating the need to consider ribbon alignment during the welding process; comprehensive welding can be performed directly. In contrast, conventional battery string welding requires positioning and pulling the solder ribbon from each battery cell 2, pressing it onto the silver paste points with a clamp, and then welding it individually. The integrated design allows for faster and more convenient battery string welding.

[0063] This embodiment does not limit the specific method of placing the photovoltaic welding ribbon 1, as long as it can be placed in the welding ribbon placement groove 31. For example, multiple photovoltaic welding ribbons 1 of target length can be pulled out by a welding ribbon clamping machine and placed in the welding ribbon placement groove 31 on the mold 3.

[0064] This embodiment does not limit the specific method of placing the battery cell 2, as long as it can be placed in the battery cell placement position 34. For example, multiple back-contact battery cells 2 can be transported to the battery cell placement position 34 formed by the battery cell limiting post 33 on the mold 3 according to the component layout diagram by a mechanical gripper.

[0065] This embodiment does not limit the specific type and size of mold 3. For example, high temperature resistant mold 3 such as aluminum mold 3 can be used. The size of mold 3 can be consistent with the size of mainstream products on the market, such as 2278mm×1134mm, 2465mm×1134mm, 2382mm×1303mm, etc.

[0066] This embodiment does not limit the specific dimensions of the solder strip placement groove 31. For example, the depth of the solder strip placement groove 31 can be 0.3mm to 0.35mm, including the values ​​at both ends; the width of the solder strip placement groove 31 can be 0.3mm to 0.4mm, including the values ​​at both ends. This embodiment does not limit the specific number of solder strip placement grooves 31. The specific number of solder strip placement grooves 31 can be determined according to the actual number of battery strings required and the specific number of grid lines on each battery cell 2.

[0067] This embodiment does not limit the specific dimensions of the battery cell limiting post 33. For example, the diameter of the battery cell limiting post 33 can be 0.5mm to 1.5mm, including the values ​​at both ends; the height of the battery cell limiting post 33 can be 0.2mm to 0.4mm.

[0068] This embodiment does not limit the specific temperature and time of hot air welding. For example, the temperature of the hot air can be 150℃ to 260℃, including the values ​​at both ends; the welding time can be 1s to 3s, including the values ​​at both ends.

[0069] S102: After the photovoltaic ribbon is magnetically pre-fixed to the solar cell, the photovoltaic ribbon is welded to obtain a welded solar cell string.

[0070] S103: Photovoltaic modules are prepared based on welded battery strings.

[0071] This embodiment does not limit the specific method of preparing back-contact battery modules based on back-contact battery strings. The specific method of preparing photovoltaic modules can be determined according to the actual photovoltaic module structure. For example, the welded battery strings can be placed on the encapsulation backplate 41 with a layer of adhesive film 42 laid on it by a mechanical gripper and sent into a stacking welding machine for stacking welding. After the stacking welding is completed, two layers of adhesive film 44 and front glass 45 are laid on the front side of the battery strings in sequence and sent into a laminator for lamination and subsequent processes to prepare photovoltaic modules.

[0072] Based on the above embodiments, this application provides conductive electromagnetic attraction contacts on the photovoltaic ribbon and the solar cell, fixing the photovoltaic ribbon and the solar cell by magnetic attraction. Compared with traditional coating, dispensing, or welding-dispensing methods, the magnetic attraction method has the advantages of having no impact on the solar cell, not causing grid breakage, not causing shading or EL detection shadows, and the magnetic attraction force is greater than that of coating and dispensing methods. Precisely fixing the photovoltaic ribbon to the solar cell by magnetic attraction before welding can prevent problems such as ribbon displacement and warping caused by the high temperature of the string welding machine during the welding process.

[0073] The following example illustrates the photovoltaic module manufacturing process, which is as follows:

[0074] 1. Using a welding strip clamping machine, pull out the photovoltaic welding strip 1 to a suitable length and place it in a suitable location. Figure 5 In the aluminum mold 3 shown for integrated welding, the photovoltaic welding ribbon 1 is adjusted so that the magnetic contact can correspond to the nickel-plated pad on the back of the battery cell 2 in the welding ribbon placement groove 31.

[0075] 2. The battery cell 2 is transported onto the aluminum mold 3 according to the component layout diagram using a mechanical gripper. The battery cell limiting post 33 is used to fix the position of the battery cell 2 horizontally to prevent displacement.

[0076] 3. After the positions of the solar cell 2 and photovoltaic ribbon 1 are in place, the solar cell 2 and photovoltaic ribbon 1 are fixed by magnetic attraction. At this time, check the attraction.

[0077] 4. After ensuring that the magnetic adsorption is completed, turn on the heating module and blow hot air into the air blowing hole 32 of the aluminum mold 3 for overall heating and welding. The temperature is adjustable from 150℃ to 260℃ (including the values ​​at both ends), and the welding time is 1s to 3s (including the values ​​at both ends).

[0078] 5. After welding, the welded battery matrix 43 (including multiple battery strings) is placed on the encapsulation backplate 41 with a layer of adhesive film 42 laid on it by a mechanical gripper and sent to the stacking welding machine for stacking welding.

[0079] 6. The second layer of adhesive film 44 and the front glass 45 are laid in two layers and then fed into a laminator for lamination and subsequent processes to prepare the desired product. Figure 6 The photovoltaic module shown.

[0080] This document uses specific examples to illustrate the principles and implementation methods of this application. The various embodiments are progressive, with each embodiment focusing on its differences from others. Similar or identical parts between embodiments can be referred to interchangeably. The descriptions of the embodiments above are merely illustrative of the method and core ideas of this application. For those skilled in the art, various improvements and modifications can be made to this application without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this application.

[0081] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

Claims

1. A photovoltaic welding strip, characterized in that, include: Conductive base strip; the welding surface of the conductive base strip is provided with a first electromagnetic attraction point; The welding surface is the side surface of the conductive baseband used for welding with the grid lines of the battery cell. The first conductive magnetic attraction contact is used to magnetically connect the conductive baseband to the surface of the battery cell, and to make the conductive baseband electrically connected to the grid lines.

2. The photovoltaic welding strip according to claim 1, characterized in that, The first electromagnetic attraction contact is embedded in the welding surface; the height of the surface of the first electromagnetic attraction contact near the grid line is higher than that of the welding surface.

3. The photovoltaic welding strip according to claim 1, characterized in that, The conductive baseband is a flat conductive baseband; the conductive baseband includes a copper substrate and a tin layer covering the periphery of the copper substrate.

4. The photovoltaic welding strip according to any one of claims 1 to 3, characterized in that, The welding surface of the conductive base strip is provided with a plurality of first electromagnetic attraction points along the extension direction of the conductive base strip; the first electromagnetic attraction points are located on the center line of the welding surface parallel to the extension direction.

5. A battery string, characterized in that, include: The present invention comprises multiple solar cells and photovoltaic ribbons connecting adjacent solar cells. The photovoltaic ribbons include a conductive base strip, and the welding surface of the conductive base strip is provided with a first electromagnetic attraction point. Each solar cell includes a substrate, and the surface of the substrate is provided with grid lines and a second electromagnetic attraction point. The second electromagnetic attraction point of the solar cell contacts the first electromagnetic attraction point of the photovoltaic ribbon, for magnetically connecting the photovoltaic ribbon to the surface of adjacent solar cells, and making the photovoltaic ribbon electrically connected to the grid lines of the solar cells.

6. The battery string according to claim 5, characterized in that, The second conductive electromagnetic attraction contact is disposed on the surface of the grid line or connected to the grid line.

7. The battery string according to claim 6, characterized in that, The grid line includes a main grid and a sub-grid. The surface of the main grid is provided with a plurality of second electromagnetic attraction points along its extension direction. The second electromagnetic attraction points correspond one-to-one with the first electromagnetic attraction points of the photovoltaic ribbon.

8. The battery string according to claim 5, characterized in that, The second conductive electromagnetic attraction contact is a nickel-plated pad.

9. The battery string according to claim 6, characterized in that, The grid line includes a positive electrode main grid and a negative electrode main grid; both the positive electrode main grid and the negative electrode main grid are disposed on the back side of the substrate, which is the side of the substrate that faces away from sunlight; The positive electrode main gate and the negative electrode main gate extend along a first direction and are alternately arranged along a second direction; the positive electrode main gate is in electrical contact with a plurality of positive electrode sub-gates, and the negative electrode main gate is in electrical contact with a plurality of negative electrode sub-gates; The positive electrode sub-gate and the negative electrode sub-gate extend along the second direction and are alternately arranged along the first direction; The positive electrode main grid surface is provided with the second electromagnetic attraction point; the negative electrode main grid surface is provided with the second electromagnetic attraction point.

10. A method for manufacturing a photovoltaic module, characterized in that, include: Multiple photovoltaic ribbons are magnetically connected to the first electromagnetic attraction points of multiple solar cells to form a battery string. After the photovoltaic ribbon is magnetically pre-fixed to the battery cell, the photovoltaic ribbon is welded to obtain the welded battery string; The photovoltaic module is prepared based on the welded battery string.

11. The method for preparing a photovoltaic module according to claim 10, characterized in that, When the solar cell is a back-contact solar cell, the step of magnetically connecting the first electromagnetic attraction points of multiple photovoltaic ribbons with the second electromagnetic attraction points of multiple solar cells to form a battery string includes: Multiple photovoltaic ribbons are placed in ribbon placement slots on a mold; the ribbon placement slots are provided with air blowing holes inside. After placement, multiple back-contact solar cells are placed on the mold in the solar cell placement position surrounded by solar cell limiting posts, so that the second electromagnetic attraction point of the back-contact solar cell is magnetically connected to the first electromagnetic attraction point of the photovoltaic ribbon to form the battery string. Accordingly, the welding of the photovoltaic strips to obtain the welded battery string includes: Hot air is blown into the air blowing hole to perform hot air welding on the photovoltaic welding strip, thereby obtaining the welded battery string.

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