Solar cell module and method of manufacturing the same

Abstract

The application relates to a solar cell module and a manufacturing method thereof. The method comprises the following steps: matching a cell string to be welded, and providing a rotatable carrier; the cell string to be welded comprises a plurality of cell pieces arranged in sequence in a first direction, and a plurality of first grid lines are arranged on the cell pieces, the plurality of first grid lines extend along the first direction and are arranged at intervals in a second direction, and the second direction is orthogonal to the first direction; the circumferential dimension of the rotatable carrier is obtained, and based on the circumferential dimension and the interval between two adjacent target first grid lines in the cell pieces, a target placing angle of the cell pieces when placed along the circumference of the rotatable carrier is determined; the cell pieces are placed on the rotatable carrier according to the target placing angle; a conductive wire is spirally wound on the first grid lines of each cell piece along the circumference of the rotatable carrier; and the conductive wire and the first grid lines are welded to form the cell string. The application is used for realizing a high-precision, low-resistance and low-cost cell interconnection process.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, and in particular to a solar cell module and its manufacturing method. Background Technology

[0002] In recent years, with the continuous depletion of traditional energy sources, people's environmental awareness has been constantly improving. Solar energy, as a clean energy source, has attracted much attention by directly converting solar radiation into electrical energy through solar cells.

[0003] Back-contact (BC) cells are positioned as a "high-efficiency platform" in the crystalline silicon cell technology spectrum. All metal electrodes in a back-contact cell, such as the busbar, finger, and pads, are located on the back of the cell, ensuring no metal obstruction on the front and thus increasing the effective light-receiving area. The metal electrodes in a back-contact cell are typically arranged in an interdigitated pattern, and current paths are formed through corresponding soldering between the electrodes and solder ribbons.

[0004] However, as the photovoltaic industry continues to pursue high efficiency and low resistance loss in solar cells, the spacing between metal electrodes and the width of the solder strip in back contact cells are constantly shrinking, which places higher demands on the precision welding of the solder strip. Summary of the Invention

[0005] Based on this, embodiments of this application provide a solar cell module and its manufacturing method, which facilitates increasing the number of grid lines, reducing the spacing between grid lines, and improving welding accuracy, thereby achieving a high-precision, low-resistance, and low-cost cell interconnection process, and ensuring and improving the production yield and long-term reliability of the solar cell module.

[0006] To achieve the above objectives, some embodiments of this application provide a method for manufacturing a solar cell module, which may include the following steps:

[0007] A rotatable carrier is provided for matching the battery string to be welded; wherein the battery string to be welded includes: a plurality of battery cells arranged sequentially in a first direction; a plurality of first grid lines are provided on the battery cells; the plurality of first grid lines extend along the first direction and are spaced apart in a second direction; the second direction is orthogonal to the first direction;

[0008] Obtain the circumferential dimensions of the rotatable carrier, and based on the circumferential dimensions and the spacing between two adjacent target first grid lines in the battery cell, determine the target placement angle when the battery cell is placed along the circumference of the rotatable carrier.

[0009] Place the battery cells on the rotatable vehicle according to the target placement angle;

[0010] The conductive wire is spirally wound around the first grid line of each battery cell along the circumference of the rotatable carrier.

[0011] The conductive wires and the first grid line are welded together to form a battery string.

[0012] In some embodiments of this application, the rotatable carrier includes a cylindrical roller.

[0013] Accordingly, determining the target placement angle of the battery cell when it is placed along the circumference of the rotatable carrier, based on the circumferential dimension and the spacing between two adjacent target first grid lines in the battery cell, may include the following steps:

[0014] Define the spacing between two adjacent target first grid lines as X, the circumferential dimension as Y, and the first included angle as θ1;

[0015] Determine the first included angle using the formula: θ1 = arcsin(X / Y);

[0016] The target placement angle is equal to the first included angle.

[0017] In some embodiments of this application, the spacing between two adjacent target first gate lines ranges from 1.5mm ± 0.1mm to 8mm ± 0.1mm.

[0018] In some embodiments of this application, the width of the conductive wire is ≥0.1mm.

[0019] In some embodiments of this application, the product of the spacing between two adjacent target first grid lines in the same battery cell and the number of first grid lines in the battery cell minus one is no greater than 230mm.

[0020] In some embodiments of this application, each cell in the battery string to be welded has the same number of first grid lines, and the number of first grid lines in each cell ranges from 30 to 120.

[0021] In some embodiments of this application, 0° ≤ the absolute value of the target placement angle ≤ 1°.

[0022] Optionally, the absolute value of the target placement angle can range from 0.051° to 0.638°.

[0023] In some embodiments of this application, the battery cell is provided with a first mark point and a second mark point spaced apart along a first direction. Determining the target placement angle of each battery cell when it is placed along the circumference of a rotatable carrier, based on the circumferential dimension and the spacing between two adjacent target first grid lines in the battery cell, may include the following steps:

[0024] Define the spacing between two adjacent target first grid lines as X, the circumferential dimension as Y, and the first included angle as θ1; determine the first included angle according to the formula: θ1=arcsin(X / Y);

[0025] The battery cells are placed on the rotatable carrier at the first included angle;

[0026] The first distance from the first marker point to the reference baseline, the second distance from the second marker point to the reference baseline, and the third distance between the first marker point and the second marker point are obtained respectively, and the first correction angle is determined based on the first distance, the second distance, and the third distance.

[0027] The target placement angle is determined based on the first included angle and the first correction angle.

[0028] In some embodiments of this application, determining the first correction angle based on the first distance, the second distance, and the third distance may include the following steps:

[0029] Define the first distance as d1, the second distance as d2, the third distance as d3, the second included angle as θ2, and the first correction angle as Δθ1;

[0030] Determine the second included angle using the formula θ2 = arcsin [(d1-d2) / d3];

[0031] The first correction angle is determined according to the formula Δθ1=θ1 - θ2;

[0032] The target placement angle is equal to the sum of the first included angle and the first correction angle.

[0033] In some embodiments of this application, the solar cell is provided with a plurality of second grid lines respectively connected to each first grid line. The plurality of second grid lines extend along a second direction and are spaced apart in a first direction. After welding conductive wires and first grid lines to form a cell string, the method for manufacturing a solar cell module may further include the following steps:

[0034] Determine the first grid line to be tested, and select two target second grid lines from the second grid lines connected to the first grid line to be tested;

[0035] Obtain the endpoint positions of the two target second gate lines located on the same side of the corresponding conductive wire, and define them as the first endpoint position and the second endpoint position, respectively;

[0036] The fourth distance from the first endpoint position to the corresponding conductive wire, the fifth distance from the second endpoint position to the corresponding conductive wire, and the sixth distance between the first endpoint position and the second endpoint position are obtained respectively, and the second correction angle is determined based on the fourth distance, the fifth distance and the sixth distance;

[0037] The target placement angle of the cells in the next battery string to be welded is updated based on the second correction angle.

[0038] In some embodiments of this application, determining the second correction angle based on the fourth distance, the fifth distance, and the sixth distance may include the following steps:

[0039] Define the fourth distance as d4, the fifth distance as d5, the sixth distance as d6, and the second correction angle as Δθ2;

[0040] The second correction angle is determined using the formula Δθ2 = arcsin [(d5-d4) / d6].

[0041] The target placement angle of the cells in the next battery string to be welded is equal to the sum of the target placement angle of the cells in the current battery string to be welded and the second correction angle.

[0042] In some embodiments of this application, determining the first gate line to be tested may include the following steps:

[0043] Multiple detection areas are divided on the solar cell.

[0044] Within each detection area, a preset number of first grid lines are randomly selected or selected according to preset rules as the first grid lines to be tested.

[0045] Accordingly, updating the target placement angle of the cells in the next battery string to be welded based on the second correction angle includes: updating the target placement angle of the cells in the next battery string to be welded based on the average value of the second correction angle corresponding to each first grid line to be tested.

[0046] In some embodiments of this application, determining the first grid line to be tested includes: selecting the first grid line to be tested in a critical region of the battery cell; wherein, the critical region includes: the starting region or the middle region of the arrangement of each first grid line along the winding direction of the conductive wire.

[0047] In some embodiments of this application, matching the battery string to be welded and providing a rotatable carrier may include the following steps:

[0048] Obtain the unfolded length of the battery string to be welded in the first direction;

[0049] The target perimeter is determined based on the unfolded length; the target perimeter is greater than or equal to the unfolded length;

[0050] Provides a rotatable vehicle with a perimeter equal to the target perimeter.

[0051] In some embodiments of this application, after the conductive wire is spirally wound around the first grid line of each solar cell and before the conductive wire and the first grid line are welded, the method for manufacturing a solar cell module further includes the following steps:

[0052] A curable adhesive is applied to multiple areas of the structure obtained after winding the conductive wire; wherein the areas to be coated extend along a second direction, and the multiple areas to be coated are spaced apart in a first direction.

[0053] The curable adhesive is cured to form a cured adhesive strip; the cured adhesive strip is used to fix and connect the conductive wire and the battery cell.

[0054] In some embodiments of this application, the curing process of the curable adhesive includes a photocuring process or a thermocuring process.

[0055] In some embodiments of this application, the curing process of the curable adhesive is a thermosetting process; wherein, the heating temperature of the thermosetting process ranges from 100°C to 300°C; and the heating time of the thermosetting process ranges from 1 min to 60 min.

[0056] In some embodiments of this application, welding conductive wires and first grid lines to form a battery string includes: placing the resulting structure after winding the conductive wires in a heating environment; and heating the conductive wires based on the heating environment to weld the conductive wires to the first grid lines to form a battery string.

[0057] In some embodiments of this application, the heating temperature provided by the heating environment ranges from 100°C to 500°C.

[0058] In some embodiments of this application, the conductive wire includes photovoltaic ribbon.

[0059] In some embodiments of this application, the method for manufacturing a solar cell module further includes: patterning conductive wires to form a plurality of sub-conductive wires.

[0060] In some embodiments of this application, the method for manufacturing a solar cell module further includes: coating an encapsulating adhesive layer to encapsulate the cell string.

[0061] Optionally, the solar cell has multiple second grid lines connected to each of the first grid lines. The multiple second grid lines extend along a second direction and are spaced apart in a first direction; wherein the sub-conductive wires are isolated from the second grid lines connected to adjacent first grid lines by an encapsulating adhesive layer or by an air gap.

[0062] In some embodiments of this application, the maximum offset between the center line of the conductive wire and the center line of the first gate line is no greater than 0.15 mm.

[0063] On the other hand, some embodiments of this application also provide a solar cell module, which can be prepared using the manufacturing method of the solar cell module described in the above embodiments. The solar cell module includes: a cell string and a plurality of sub-conductive wires. The cell string includes: a plurality of cells arranged sequentially in a first direction. A plurality of first grid lines are provided on the cells. The plurality of first grid lines extend along the first direction and are spaced apart in a second direction, the second direction being orthogonal to the first direction. Sub-conductive wires are welded to the first grid lines covered by the sub-conductive wires.

[0064] In some embodiments of this application, the solar cell has multiple second grid lines connected to each first grid line. The multiple second grid lines extend along a second direction and are spaced apart in a first direction. The solar cell module further includes an encapsulating layer for encapsulating the cell string. Sub-conducting filaments are isolated from adjacent first grid lines connected to second grid lines by the encapsulating layer or by an air gap.

[0065] In some embodiments of this application, the maximum offset between the center line of the sub-conductive wire and the center line of the first gate line is no greater than 0.15 mm.

[0066] In some embodiments of this application, the spacing between adjacent first grid lines in the same battery cell ranges from 1.5mm ± 0.1mm to 8mm ± 0.1mm.

[0067] In some embodiments of this application, the width of the sub-conductive filament is ≥0.1mm.

[0068] In some embodiments of this application, the product of the spacing between adjacent first grid lines in the same battery cell and the number of first grid lines in the battery cell minus one is no greater than 230mm.

[0069] In some embodiments of this application, each battery cell in the battery string has the same number of first grid lines, and the number of first grid lines in each battery cell ranges from 30 to 120.

[0070] In some embodiments of this application, the battery cell is provided with multiple second grid lines respectively connected to each first grid line. The multiple second grid lines extend along a second direction and are spaced apart in a first direction. In the same battery cell, the second grid lines connected to any two adjacent first grid lines are staggered in the first direction. A second grid line connected to any first grid line is designated as a first group of grid lines, and the second grid lines corresponding to two adjacent first grid lines are designated as a second group of grid lines and a third group of grid lines, respectively. The second grid lines in the second group and the second grid lines in the third group are aligned in the first direction, and the spacing between any two relative second grid lines in the second and third groups is ≥0.2 mm.

[0071] The embodiments of this application may have, or at least have, the following advantages:

[0072] In this embodiment, a rotatable carrier is provided to match the battery string to be welded. The target placement angle of the battery cells when they are placed along the circumference of the rotatable carrier is determined based on the circumferential dimensions of the rotatable carrier and the spacing between two adjacent target first grid lines in the battery cells. Then, the battery cells are placed on the rotatable carrier according to the target placement angle. A single conductive wire can be spirally wound around the first grid line of each battery cell along the circumference of the rotatable carrier to achieve the alignment of the conductive wire and the first grid line, so as to facilitate the subsequent welding of the conductive wire and the first grid line to obtain the battery string. This application embodiment can establish a reference coordinate system based on a rotatable carrier, and achieve welding between the conductive wire and the first grid line by pre-determining the target placement angle, placing the battery cells according to the target placement angle, and self-aligning and winding the conductive wire. This facilitates sub-millimeter-level dimensional alignment of the conductive wire relative to the first grid line, effectively eliminating the inertial offset caused by the high-speed back-and-forth placement of multiple conductive wires by the robotic arm, and eliminating the need for insulating adhesive isolation and metal solder compensation. This allows for increasing the number of first grid lines, reducing the spacing between the first grid lines, and improving welding accuracy, thereby enabling high-precision, low-resistance, and low-cost battery interconnection processes, and ensuring and improving the production yield and long-term reliability of solar cell modules.

[0073] Details of one or more embodiments of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0074] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0075] Figure 1 This is a schematic flowchart illustrating a method for manufacturing a solar cell module provided in some embodiments;

[0076] Figure 2 This is a schematic flowchart illustrating another method for manufacturing a solar cell module provided in some embodiments;

[0077] Figure 3 This is a schematic diagram of the structure of an automatic string welding device provided in some embodiments;

[0078] Figure 4 This is a schematic diagram of the structure obtained after a rotatable carrier adsorbs a battery cell, as provided in some embodiments.

[0079] Figure 5 This is a schematic diagram of the structure of a battery cell provided in some embodiments;

[0080] Figure 6 This is a schematic diagram showing the target placement angle of the battery cells after the rotatable carrier is circumferentially deployed, as provided in some embodiments.

[0081] Figure 7 This is a schematic diagram of a robotic arm placing battery cells in some embodiments;

[0082] Figure 8 This is a schematic diagram of a second included angle provided in some embodiments;

[0083] Figure 9 This is a schematic diagram of a state when a conductive wire is wound, as provided in some embodiments;

[0084] Figure 10 This is a schematic diagram illustrating a state when applying a curable adhesive, as provided in some embodiments.

[0085] Figure 11 This is a schematic diagram illustrating the state of a curable adhesive during curing, as provided in some embodiments.

[0086] Figure 12 This is a schematic diagram showing the distribution of a curing adhesive strip provided in some embodiments;

[0087] Figure 13 This is a schematic diagram of a state during welding of a conductive wire and a first grid line, provided in some embodiments;

[0088] Figure 14 This is a schematic diagram of the structure of another battery cell provided in some embodiments;

[0089] Figure 15 This is a partial cross-sectional schematic diagram of a solar cell module provided in some embodiments;

[0090] Figure 16 This is a partial cross-sectional schematic diagram of another solar cell module provided in some embodiments;

[0091] Figure 17 This is a schematic diagram of a second correction angle provided in some embodiments.

[0092] Explanation of reference numerals in the attached figures:

[0093] 10-Battery string to be welded, 11-Battery cell, 111-First grid line, 112-Second grid line, 12-Conductive wire, 121-Sub-conductive wire, 13-Encapsulating adhesive layer, G-Air gap, 20-Rotating carrier, 31-Robot arm, 40-Guiding mechanism, 50-Glue application mechanism, 51-Curing adhesive strip, 60-Curing light box, 70-Infrared light box, U1-First group of grid lines, U2-Second group of grid lines, U3-Third group of grid lines. Detailed Implementation

[0094] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the application. However, this application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0095] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0096] It should be understood that when an element or layer is referred to as being "on," "adjacent to," or "connected to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, regions, layers, doping types, and / or portions, these elements, components, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, doping type, or portion from another element, component, region, layer, doping type, or portion. Therefore, without departing from the teachings of this application, the first element, component, region, layer, doping type, or portion discussed below may be referred to as a second element, component, region, layer, or portion.

[0097] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that when the terms “comprise” and / or “comprising” are used in this specification, the presence of the stated feature, integer, step, operation, element, and / or part is established, but the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups is not excluded. Meanwhile, when used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0098] Currently, as the photovoltaic industry continues to pursue high efficiency and low resistance loss in solar cells, the spacing between metal electrodes and the width of the solder strip in back contact cells are constantly shrinking, which places higher demands on the precision welding of the solder strip.

[0099] For example, the metal electrodes of the back-contact battery include: multiple main grids distributed in parallel intervals, and multiple fine grids distributed in a herringbone pattern on both sides of the main grids, with the fine grids connected to adjacent main grids alternating in a staggered manner along their distribution direction. In this way, current can be injected vertically into the main grids from the fine grids, thereby shortening the lateral transmission distance (i.e., shortening the current collection path) and reducing series resistance losses. Optionally, adjacent main grids are opposite-polarity main grids, and the fine grids connected to them are opposite-polarity fine grids, i.e., positive and negative electrode fine grids, respectively. Based on this, during the component interconnection stage of the back-contact battery, if the solder ribbon experiences a slight lateral drift during placement, it may cross the opposite-polarity fine grids connecting the corresponding main grids, causing a short circuit in the opposite-polarity fine grids.

[0100] In some examples, automated stringing equipment often employs a three-step process of "hover-bonding-welding," specifically including the following steps: a robotic arm moves the solder strip horizontally to directly above the target main grid; a pressure mesh is placed to bond the solder strip to the battery busbar pads; and the bonding is maintained and heated to complete the alloying welding. Thus, in the high-speed reciprocating motion of the robotic arm, the solder strip is subjected to the coupling effect of both motion inertia (e.g., its lateral component) and bonding pressure (e.g., its vertical component) at the moment of downward pressure, causing a random offset in the landing position of the solder strip. Publicly available production data and the applicant's verification both indicate that even with servo closed-loop calibration of the automated stringing equipment, the placement error of the solder strip is not conducive to increasing the number of main grids and is prone to short-circuit risks when the center-to-center distance of the fine grids is small.

[0101] In other examples, a combination of "insulating adhesive isolation + metal solder compensation" can address the short-circuit risk in the aforementioned examples. For instance, depositing a solvent-based polymer insulating adhesive (e.g., acrylic or epoxy-based) approximately 30 μm thick on the non-polar fine grid via screen printing or inkjet printing can form a high-dielectric-strength barrier layer between the solder ribbon and the fine grid, thus preventing electrical short circuits. However, after curing, this insulating adhesive forms a step on the surface of the fine grid, meaning the height of the insulating adhesive exceeds that of the uncoated area. This disrupts the coplanar contact between the solder ribbon and the main grid, leading to subsequent problems such as solder gaps, increased contact resistance, and decreased solder joint reliability. Therefore, metal solder needs to be printed again in the soldering area and reflow soldering is required to fill the height difference caused by the insulating adhesive after the solder flows and solidifies, and to perform secondary alloying with the solder ribbon. While this restores the flat contact interface between the solder strip and the main grid, which helps ensure welding strength and electrical continuity, it also presents several problems. For example, it increases the cost of metal paste, as well as printing and reflow processes, which can significantly increase manufacturing cycle time and Bill of Material (BOM) costs. The interface compounds and pores remaining in the secondary heterogeneous solder joints can increase series resistance and easily cause thermal and mechanical fatigue. Solvent evaporation, solder shrinkage, and repeated heating cycles can easily lead to inclusions, voids, and odor emissions, posing risks to long-term reliability and environmental compliance.

[0102] Furthermore, it is understandable that increasing the number of main grids and reducing the grid spacing in back-contact cells can further reduce the current-carrying distance, significantly reduce series resistance losses within the cell, and improve the fill factor, thereby achieving low-loss output at high current densities. It also allows for the use of thinner or narrower solder strips to save metal usage and reduce thermal and mechanical stress. However, with the increase in the number of main grids and the reduction in grid spacing, existing stringing equipment will face hardware space bottlenecks, thus limiting the development of high-density grid technology.

[0103] Based on this, the present application provides a solar cell module and its manufacturing method, which is beneficial for increasing the number of grid lines, reducing the spacing between grid lines, and improving welding accuracy, thereby achieving a high-precision, low-resistance, and low-cost back-contact cell interconnection process, and ensuring and improving the production yield and long-term reliability of the solar cell module.

[0104] Please see Figure 1 Some embodiments of this application provide a method for manufacturing a solar cell module, which may include the following steps S100 to S500.

[0105] S100, matching the battery string to be welded, providing a rotatable carrier; wherein, the battery string to be welded includes: a plurality of battery cells arranged sequentially in a first direction; the battery cells are provided with a plurality of first grid lines; the plurality of first grid lines extend along the first direction and are spaced apart in a second direction; the second direction is orthogonal to the first direction.

[0106] S200: Obtain the circumferential dimension of the rotatable carrier, and based on the circumferential dimension and the distance between two adjacent target first grid lines in the battery cell, determine the target placement angle when the battery cell is placed along the circumference of the rotatable carrier.

[0107] Optionally, the rotatable carrier may include, but is not limited to, a cylindrical roller. The rotatable carrier is capable of rotating at a constant speed.

[0108] Optionally, each of the first grid lines is arranged at equal intervals in the second direction, and the target first grid line can be any first grid line.

[0109] Optionally, the spacing between at least some adjacent first grid lines is different, and the target first grid line can be selected from the first grid lines in the critical region to match the requirements. For example, the solar cell includes a main region and an edge region. The spacing between adjacent first grid lines in the main region is a first spacing, and the spacing between adjacent first grid lines in the edge region is a second spacing, and the first spacing and the second spacing are different; wherein, two adjacent target first grid lines can be any two first grid lines located in the main region.

[0110] The S300 places the battery cells on a rotatable vehicle according to the target placement angle.

[0111] Optionally, the target placement angle of each battery cell can be determined individually.

[0112] Optionally, each battery cell has the same structure, and the target placement angle of each battery cell can be determined according to the target placement angle of any one of the battery cells.

[0113] Optionally, the rotatable carrier can vacuum-adsorb the battery cells to achieve placement and fixation of the battery cells on the rotatable carrier.

[0114] S400, along the circumference of the rotatable carrier, the conductive wire is spirally wound onto the first grid line of each battery cell.

[0115] S500, welding conductive wires and the first grid line to form a battery string.

[0116] Optionally, the conductive wire includes, but is not limited to, photovoltaic solder ribbon.

[0117] In this embodiment, a rotatable carrier is provided to match the battery string to be welded. The target placement angle of the battery cells when they are placed along the circumference of the rotatable carrier is determined based on the circumferential dimensions of the rotatable carrier and the spacing between two adjacent target first grid lines in the battery cells. Then, the battery cells are placed on the rotatable carrier according to the target placement angle. A single conductive wire can be spirally wound around the first grid line of each battery cell along the circumference of the rotatable carrier to achieve the alignment of the conductive wire and the first grid line, so as to facilitate the subsequent welding of the conductive wire and the first grid line to obtain the battery string. This application embodiment can establish a reference coordinate system based on a rotatable carrier, and achieve welding between the conductive wire and the first grid line by pre-determining the target placement angle, placing the battery cells according to the target placement angle, and self-aligning and winding the conductive wire. This facilitates sub-millimeter-level dimensional alignment of the conductive wire relative to the first grid line, effectively eliminating the inertial offset caused by the high-speed back-and-forth placement of multiple conductive wires by the robotic arm, and eliminating the need for insulating adhesive isolation and metal solder compensation. This allows for increasing the number of first grid lines, reducing the spacing between the first grid lines, and improving welding accuracy, thereby enabling high-precision, low-resistance, and low-cost battery interconnection processes, and ensuring and improving the production yield and long-term reliability of solar cell modules.

[0118] Please refer to some embodiments of this application. Figure 2 The method for manufacturing solar cell modules also includes step S600.

[0119] S600, patterned conductive wires, forming multiple sub-conductive wires.

[0120] Here, the connection relationship between the matching sub-conductive wire and the first gate line can be used to pattern the conductive wire to divide the conductive wire into multiple sub-conductive wires.

[0121] For example, the patterning process of conductive wires includes, but is not limited to, cutting processes.

[0122] In this embodiment, after spirally winding a single conductive wire around the first grid line of each battery cell and welding the conductive wire to the corresponding first grid line, multiple sub-conductive wires are obtained by cutting the conductive wire. This avoids repeating the conductive wire alignment and welding process multiple times, which helps to improve production efficiency and production yield.

[0123] It should be added that, in some embodiments of this application, the matching of the battery string to be welded and the provision of a rotatable carrier in step S100 may include the following steps S110 to S130.

[0124] S110, Obtain the unfolded length of the battery string to be welded in the first direction.

[0125] Here, the component templates of the battery strings to be welded are different, and the unfolded length of the battery strings to be welded can be different.

[0126] Optionally, the unfolded length of the battery string to be welded can be in the range of 728mm to 1570mm, for example, the unfolded length can be 728mm, 1176mm or 1570mm.

[0127] S120, determine the target perimeter based on the unfolded length; the target perimeter is greater than or equal to the unfolded length.

[0128] S130 provides a rotatable vehicle with a circumference of the target circumference.

[0129] In this embodiment of the application, a rotatable carrier with a circumference greater than or equal to the unfolded length of the battery string to be welded is provided, which can unfold the battery string to be welded in one direction and lay it flat on the outer surface of the rotatable carrier so that the first grid line of each battery cell in a single battery string to be welded can be spirally wound around it by a single conductive wire.

[0130] In some examples, only one battery string to be welded can be placed on the rotatable carrier; or, if the axial dimension of the rotatable carrier is large, multiple battery strings to be welded can be placed at intervals along its axial direction, wherein the conductive wire corresponds one-to-one with the battery string to be welded.

[0131] It is worth mentioning that, in some embodiments, the material of the rotatable carrier is related to its moment of inertia. The aforementioned target perimeter can also be determined by combining the unfolded length of the battery string to be welded with the material of the rotatable carrier, in order to select the rotatable carrier more accurately.

[0132] Optionally, the rotatable carrier is a cylindrical roller with a material density greater than 7 g / cm³. 3 The material can be, for example, stainless steel or aluminum alloy. Furthermore, the cylindrical roller can be either a hollow roller or a solid roller.

[0133] In some examples, the radius of the cylindrical roller is defined as R, and the circumference as Y, then Y = 2πR, and R ≥ 115 mm.

[0134] To clearly illustrate the manufacturing method of the solar cell module provided in the embodiments of this application, Figure 3 An exemplary structural schematic diagram of an automatic string welding device is provided. The following embodiments incorporate... Figure 3 The apparatus shown provides a detailed description of the implementation of a method for manufacturing solar cell modules.

[0135] Please combine Figure 3 and Figure 4At the loading station, a rotatable carrier 20 is provided to match the battery string 10 to be welded. After determining the target placement angle θ corresponding to the battery cell 11, the battery cell 11 is placed on the rotatable carrier 20 according to the target placement angle θ. There are multiple ways to determine the target placement angle θ corresponding to the battery cell 11.

[0136] Please refer to some embodiments of this application. Figure 5 and Figure 6 In step S200, the target placement angle of the battery cell when it is placed along the circumference of the rotatable carrier is determined based on the circumferential dimension and the distance between two adjacent target first grid lines in the battery cell. This may include the following steps S210 and S220.

[0137] S210, define the spacing between the first grid lines of two adjacent targets as X, the circumferential dimension of the rotatable vehicle as Y, and the first included angle as θ1.

[0138] S220, according to the formula: θ1=arcsin(X / Y), determine the first included angle θ1; where the target placement angle θ is equal to the first included angle θ1, that is, θ=θ1.

[0139] In some examples, with Figure 5 Taking the battery cell 11 shown as an example, the battery cell 11 is provided with a plurality of first grid lines 111, which are arranged at equal intervals, for example, in the second direction. Assuming that each battery cell 11 in the battery string 10 to be welded has been sequentially placed on the circumferential surface of the rotatable carrier 20 according to the target placement angle θ, then as follows... Figure 6 As shown, after the circumferential surface of the rotatable carrier 20 is laid flat, the conductive wire 12 is spirally wound around the first grid line 111 of each battery cell 11. The conductive wire 12 can form a spiral trajectory with a pitch of X and a helix angle of θ on the circumferential surface of the rotatable carrier 20, that is, the winding pitch of the conductive wire 12 can be equal to the spacing between adjacent first grid lines in the same battery cell 11. Furthermore, Figure 6 The two points A shown are at the same location when the circumferential surface of the rotatable carrier 20 is a cylindrical surface. Based on this, when the spacing between two adjacent target first grid lines is defined as X, the circumferential dimension of the rotatable carrier 20 is Y, and the first included angle is θ1, then the first included angle θ1 = arcsin(X / Y). In this embodiment, setting the target placement angle θ equal to the first included angle θ1 ensures that a single conductive wire is aligned and wound between the first grid line 111 on each battery cell 11.

[0140] It is understood that in embodiments where the spacing between some adjacent first grid lines is different, after the battery cell 11 is placed according to the target placement angle θ, the conductive wire 12 can be spirally wound around each first grid line 111 aligned with the circumferential surface of the rotatable carrier 20.

[0141] For example, the spacing X between two adjacent target first gate lines 111 can range from 1.5mm ± 0.1mm to 8mm ± 0.1mm. For instance, the spacing X between two adjacent target first gate lines 111 can be 1.4mm, 1.5mm, 1.6mm, 1.9mm, 2.0mm, 2.1mm, 4.9mm, 5.0mm, 5.1mm, 7.9mm, 8.0mm, or 8.1mm, etc. This embodiment of the application can improve the manufacturing precision of the first gate line 111 to ±0.1mm, i.e., sub-millimeter level.

[0142] For example, 0° ≤ absolute value of the target placement angle ≤ 1°.

[0143] Here, the target placement angle matching the placement direction of the battery cell 11 relative to the edge of the rotatable carrier 20 end face can be positive or negative; for example, it can be positive when the battery cell 11 is placed clockwise relative to the edge of the rotatable carrier 20 end face, and negative when the battery cell 11 is placed counterclockwise relative to the edge of the rotatable carrier 20 end face.

[0144] In some examples, the absolute value of the target placement angle ranges from 0.051° to 0.638°. For example, the target placement angle could be 0.051°, 0.087°, 0.195°, 0.389°, or 0.638°.

[0145] In some examples, taking a rotatable carrier 20 as a cylindrical roller with a radius R = 375 mm, and a spacing X = 8 mm between two adjacent target first grid lines in the same solar cell 11, the target placement angle θ = θ1 = 0.389° can be calculated using the formula θ1 = arcsin(X / Y). Similarly, by matching different values ​​of the radius in the cylindrical roller and different values ​​of the spacing between two adjacent target first grid lines in the same solar cell 11, the target placement angle can be calculated based on the aforementioned formula.

[0146] In some embodiments of this application, the product of the spacing between two adjacent target first grid lines in the same battery cell and the number of first grid lines in the battery cell minus one is no greater than 230mm.

[0147] Optionally, each cell in the battery string to be welded has the same number of first grid lines, and the number of first grid lines in each cell ranges from 30 to 120; for example, it can be 30, 40, 50, 60, 80, 100 or 120.

[0148] In some embodiments, please combine Figure 3 and Figure 7Understandably, the battery cell 11 is typically placed onto the rotatable carrier 20 by the robot's manipulator 31. Specifically, the manipulator 31 generally places the battery cell 11 in the appropriate position based on the position data of the battery cell 11 obtained through visual positioning and the position of the rotatable carrier 20. Then, the rotatable carrier 20 adheres to and secures the battery cell 11.

[0149] Here, it can be understood that since there is usually a small angular deviation between the robotic arm 31 when picking up the piece and the rotatable carrier 20 when positioning, please refer to other embodiments of this application. Figure 8 A first marker point Mark1 and a second marker point Mark2 can be set at intervals along a first direction (i.e., the extension direction of the first grid line) on the battery cell 11. A first correction angle is determined based on the measurement of the first marker point Mark1 and the second marker point Mark2, thereby compensating for the angular deviation caused by the robot arm 31 picking up the cell and the rotatable carrier 20 positioning. The embodiments of this application do not limit the shape, material, and implementation of the first marker point Mark1 and the second marker point Mark2, but only require that they can be measured and identified.

[0150] Accordingly, in step S200, the target placement angle of the battery cell when it is placed along the circumference of the rotatable carrier is determined based on the circumferential dimension and the distance between two adjacent target first grid lines in the battery cell, which may include the following steps S210'~S240'.

[0151] S210' defines the spacing between the first grid lines of two adjacent targets as X, the circumferential dimension of the rotatable vehicle as Y, and the first included angle as θ1; and determines the first included angle θ1 according to the formula: θ1=arcsin(X / Y).

[0152] S220', the battery cells are placed on the rotatable carrier at the first included angle.

[0153] S230', respectively obtain the first distance from the first marker point to the reference baseline, the second distance from the second marker point to the reference baseline, and the third distance between the first marker point and the second marker point, and determine the first correction angle based on the first distance, the second distance and the third distance.

[0154] Optionally, the reference baseline is a virtual straight line, the extension direction of the reference baseline is parallel to the axis of the rotatable carrier, and the reference baseline, the first mark point Mark1, and the second mark point Mark2 can be located in the same plane parallel to the surface of the battery cell.

[0155] S240', determine the target placement angle based on the first included angle and the first correction angle.

[0156] For example, such as Figure 8As shown, the determination of the first correction angle based on the first distance, the second distance, and the third distance in step S230' may include the following steps S231 to S233.

[0157] S231, define the first distance as d1, the second distance as d2, the third distance as d3, the second included angle as θ2, and the first correction angle as Δθ1.

[0158] S232, according to the formula θ2 = arcsin [(d1-d2) / d3], determine the second included angle θ2.

[0159] S233, according to the formula Δθ1=θ1 - θ2, determine the first correction angle Δθ1.

[0160] Accordingly, in step S240', the target placement angle θ is equal to the sum of the first included angle θ1 and the first correction angle Δθ1; that is, θ = θ1 + Δθ1.

[0161] In this embodiment, after the battery cells are placed on the rotatable carrier at a first included angle, the actual placement angle of the battery cells (i.e., the second included angle θ2) can be measured based on the first marker point Mark1 and the second marker point Mark2. Therefore, the first correction angle Δθ1 can be determined based on Δθ1 = θ1 - θ2. Thus, after compensating the first included angle θ1 with the first correction angle Δθ1 to determine the target placement angle θ (i.e., θ = θ1 + Δθ1), when the robotic arm is controlled to place the battery cells at the target placement angle, the actual placement angle of the battery cells will be the first included angle θ1. This ensures that each conductive wire is aligned and wound between the battery cell 11 and the first grid line 111.

[0162] Optionally, the above-mentioned compensation correction of the target placement angle θ based on the first correction angle Δθ1 can be performed each time the robot arm adsorbs and places the battery cell.

[0163] Please combine Figure 3 and Figure 9 After the battery cells 11 are arranged at the loading station, the resulting structure can be sequentially transferred to the winding station. At the winding station, the welding strip grippers first pull and position each conductive wire 12 to the starting welding point of the rotatable carrier 20. Then, the rotatable carrier 20 is controlled to rotate at a uniform speed, and the welding strip wiring mechanism is controlled to move in a uniform linear motion. Under the guidance of the guide mechanism 40, the welding strip grippers pull the conductive wire 12 to wind around the first grid line of each battery cell 11. For example, the first grid lines 111 in each battery cell 11 are arranged at equal intervals in the second direction, and the conductive wire 12 can form a helical trajectory with a pitch of X and a helix angle of θ on the circumferential surface of the rotatable carrier 20.

[0164] In some embodiments of this application, after the conductive wire is spirally wound around the first grid line of each cell in step S400 and before the conductive wire and the first grid line are welded in step S500, the method for manufacturing a solar cell module may further include the following steps S410 and S420.

[0165] S410, a curable adhesive is applied to a plurality of adhesive-deposited areas of the structure obtained after winding the conductive wire; wherein the adhesive-deposited areas extend along a second direction, and the plurality of adhesive-deposited areas are spaced apart in a first direction.

[0166] Here, the quantity, location, and application process of the area to be glued can all be matched to the requirements and set by adjusting the parameters.

[0167] For example, please combine Figure 3 and Figure 10 After the conductive wire 12 is wound, the resulting structure can be sequentially conveyed to the adhesive application station. At the adhesive application station, a curable adhesive is applied to each area to be coated by the adhesive application mechanism 50. The curable adhesive is a polymer fixing adhesive used to fix the conductive wire after curing, to prevent the conductive wire from shifting its position before welding.

[0168] S420 cures the curable adhesive to form a cured adhesive strip; the cured adhesive strip securely connects the conductive wire and the battery cell.

[0169] Alternatively, the curing process of the curable adhesive may include a photocuring process or a thermocuring process.

[0170] In some examples, please combine Figure 3 and Figure 11 It is understood that after applying the adhesive, the resulting structure can be sequentially transferred to the curing station. At the curing station, ultraviolet light is applied through the curing light box 60, causing the curable adhesive to form a cured strip after curing.

[0171] In other examples, the curing process of the curable adhesive is a thermosetting process, such as heating with infrared radiation.

[0172] Optionally, the heating temperature range for the thermosetting process includes 100℃ to 300℃, for example, 100℃, 150℃, 200℃ or 300℃.

[0173] In some examples, the heating temperature range for the thermosetting process includes 120℃ to 150℃, such as 120℃, 130℃, 140℃ or 150℃.

[0174] Optionally, the heating time of the thermosetting process can range from 1 min to 60 min, for example, it can be 1 min, 5 min, 10 min, 30 min, 40 min, 50 min or 60 min, etc.

[0175] In some examples, the heating time for the thermosetting process ranges from 10 min to 30 min, for example, it can be 10 min, 15 min, 20 min, 25 min or 30 min.

[0176] For example, such as Figure 12 As shown, the curing strip 51 extends perpendicularly to the extension direction of the conductive wire 12. At least two curing strips 51 can be coated on each turn of the conductive wire 12.

[0177] In some embodiments of this application, the welding of conductive wires and first grid lines in step S500 to form a battery string may include the following steps S510 and S520.

[0178] S510, the resulting structure after the conductive wire is wound is placed in a heated environment.

[0179] For example, please combine Figure 3 and Figure 13 It is understood that after fixing the conductive wire 12, the resulting structure can be sequentially transferred to the welding station. At the welding station, a heating environment can be provided by controlling the heating of the infrared lamp box 70.

[0180] S520 heats the conductive wires in a heating environment to weld the conductive wires to the first grid line to form a battery string.

[0181] Here, it can be understood that both the conductive wire and the first grid line are made of metallic materials. By heating the conductive wire, a metallized connection (i.e., welding) can be achieved between the conductive wire and the first grid line.

[0182] Optionally, the heating temperature provided by the heating environment can range from 100℃ to 500℃, for example, 100℃, 120℃, 150℃, 250℃, 300℃, 400℃ or 500℃.

[0183] In some examples, the heating environment provides a heating temperature range of 150℃ to 250℃, such as 150℃, 180℃, 200℃, 220℃ or 250℃.

[0184] Optionally, when the curing process of the curable adhesive is a thermosetting process, the heating structure used for the curable adhesive can be the same infrared lamp box as the heating structure used for welding the conductive wire and the first grid line.

[0185] Based on the above, please combine Figure 3 It is understood that after welding the conductive wires and the first grid line, the resulting structure can be sequentially conveyed to the unloading station to remove the battery string.

[0186] Therefore, the method for manufacturing solar cell modules provided in this application embodiment can be based on... Figure 3 The automated string welding equipment shown completes the process cyclically from station to station. Once the worktable in the automated string welding equipment rotates to the designated station, it will automatically trigger the corresponding structure to perform the operation.

[0187] In some embodiments, the patterning process of the conductive wires is performed after the battery string is removed from the unloading station.

[0188] In some embodiments, please refer to Figure 2 The method for manufacturing solar cell modules also includes the following step S700.

[0189] S700, coated with encapsulating adhesive layer, encapsulates the battery string.

[0190] Optionally, please combine Figure 14 and Figure 15 It is understood that the battery cell 11 has multiple second grid lines 112 connected to each of the first grid lines 111. The multiple second grid lines 112 extend along a second direction and are spaced apart in a first direction. The sub-conductive wires 121 after the conductive wires are patterned are isolated from the second grid lines 112 connected to the adjacent first grid lines 111 by an encapsulating adhesive layer 13.

[0191] Optionally, please combine Figure 14 and Figure 16 It is understood that the sub-conductive wire 121 after the conductive wire is patterned is isolated from the second gate line 112 connected to the adjacent first gate line 111 by an air gap G.

[0192] It should be added that after welding the conductive wires and the first grid lines in step S500 to form the battery string, a stable system angle deviation can easily be introduced into the battery string due to the coating on the surface of the rotatable carrier (e.g., Teflon tape) and the positional tolerances between different mechanisms inside the automatic stringing equipment. This system angle deviation is related to the target placement angle of the battery cells; that is, at the same battery cell placement position, the system angle deviation is relatively stable. Based on this, please refer to some embodiments of this application. Figure 14 The solar cell 11 has multiple second grid lines 112 connected to each of the first grid lines 111. The multiple second grid lines 112 extend along a second direction (i.e., the second grid lines 112 are perpendicular to the first grid lines 111) and are spaced apart in a first direction, for example, arranged at equal intervals. Each second grid line 112 can be, for example, a grid line of equal length. The method for manufacturing the solar cell module may further include the following steps S710 to S740.

[0193] S710, determine the first grid line to be tested, and select two target second grid lines from the second grid lines connected to the first grid line to be tested.

[0194] S720, obtain the endpoint positions of the two target second gate lines located on the same side of the corresponding conductive wire, and define them as the first endpoint position and the second endpoint position, respectively. For example... Figure 17 Endpoint 1 and Endpoint 2 are shown in the diagram.

[0195] S730, respectively obtain the fourth distance from the first endpoint position to the corresponding conductive wire, the fifth distance from the second endpoint position to the corresponding conductive wire, and the sixth distance between the first endpoint position and the second endpoint position, and determine the second correction angle based on the fourth distance, the fifth distance and the sixth distance.

[0196] S740 updates the target placement angle of the cells in the next battery string to be welded based on the second correction angle.

[0197] Please refer to some embodiments of this application. Figure 17 The determination of the second correction angle based on the fourth distance, the fifth distance, and the sixth distance in step S730 may include the following steps S731 and S732.

[0198] S731, define the fourth distance as d4, the fifth distance as d5, the sixth distance as d6, and the second correction angle as Δθ2.

[0199] S732, according to the formula Δθ2= arcsin [(d5-d4) / d6], determine the second correction angle Δθ2.

[0200] Accordingly, in step S740, the target placement angle θ' of the battery cells in the next battery string to be welded is equal to the sum of the target placement angle θ of the battery cells in the current battery string to be welded and the second correction angle Δθ2; that is, θ' = θ + Δθ2.

[0201] It is understood that, based on the relevant descriptions in some of the foregoing embodiments, when the target placement angle θ = θ1 of the battery cells in the current battery string to be welded, the target placement angle θ' = θ1 + Δθ2 of the battery cells in the next battery string to be welded. Similarly, when the target placement angle θ = θ1 + Δθ1 of the battery cells in the current battery string to be welded, the target placement angle θ' = θ1 + Δθ1 + Δθ2 of the battery cells in the next battery string to be welded.

[0202] In this embodiment of the application, after welding is completed and the first grid line to be tested and two target second grid lines are determined, the second correction angle Δθ2 can be determined based on the positions of the endpoints of the two target second grid lines located on the same side of the corresponding conductive wire, i.e., the distances from endpoint 1 and endpoint 2 to the conductive wire. Please refer to... Figure 17It is understood that the second correction angle Δθ2 can effectively characterize the relative deflection between the first grid line 111 and the conductive wire 12 under the influence of system angle deviation. Thus, by compensating for the target placement angle θ' of the battery cells in the next battery string to be welded according to the second correction angle Δθ2, the system angle deviation can be effectively compensated in the manufacturing process of the next battery string to be welded, thereby further improving the alignment accuracy between the conductive wire and the first grid line 111.

[0203] Optionally, the above-mentioned compensation and correction of the target placement angle θ' of the battery cells in the next battery string to be welded based on the second correction angle Δθ2 can be performed on the first battery string to be welded in each batch, or on a preset number of battery strings to be welded. In other words, for the same batch of battery strings to be welded, the system angle deviation can be fully compensated by correcting the angle of one or a few battery strings to be welded.

[0204] Furthermore, the determination of the first gate line to be tested in step S710 above can be achieved using the following two implementation methods.

[0205] In some embodiments of this application, the region averaging method can be used to determine the first grid line to be tested. For example, determining the first grid line to be tested in step S710 may include the following steps S711 and S712.

[0206] S711 divides the solar cell into multiple detection areas.

[0207] S712, in each detection area, a preset number of first grid lines are randomly selected or selected according to preset rules as the first grid lines to be tested.

[0208] Accordingly, in step S740, updating the target placement angle of the battery cells in the next battery string to be welded based on the second correction angle can be expressed as: updating the target placement angle of the battery cells in the next battery string to be welded based on the average value of the second correction angle corresponding to each of the first grid lines to be tested. That is, in embodiments where there are multiple first grid lines to be tested, the second correction angle corresponding to each first grid line to be tested can be obtained one by one, and then the average value of each second correction angle can be calculated to update the target placement angle of the battery cells in the next battery string to be welded based on the average value of each second correction angle.

[0209] In other embodiments of this application, a specific location method can be used to determine the first grid line to be tested. For example, determining the first grid line to be tested in step S710 can be manifested as: selecting the first grid line to be tested in a key area of ​​the battery cell; wherein, the key area includes: the starting area or the middle area of ​​the arrangement of each first grid line along the winding direction of the conductive wire. That is, along the winding direction of the conductive wire, the starting first grid line can be used as the first grid line to be tested, or one or more first grid lines located in the middle area can be used as the first grid line to be tested. It can be understood that in the example where there are multiple first grid lines, the second correction angle can be the average value of the second correction angle corresponding to each first grid line to be tested.

[0210] Therefore, the embodiments of this application, through dynamic iterative correction of the target placement angle of the battery cell, can reduce the landing point error of the conductive wire to within ±0.15 mm. That is, the maximum offset between the center line of the conductive wire and the center line of the first grid line is no greater than 0.15 mm.

[0211] In some examples, the landing point error of the conductive wire can be reduced to within ±0.10 mm; that is, the maximum offset between the center line of the conductive wire and the center line of the first grid line is no greater than 0.10 mm.

[0212] In some examples, the landing point error of the conductive wire can be reduced to within ±0.05 mm; that is, the maximum offset between the center line of the conductive wire and the center line of the first grid line is no greater than 0.05 mm.

[0213] Furthermore, in some embodiments of this application, the width of the conductive wire is ≥0.1mm; for example, it can be 0.1mm, 0.2mm, 0.3mm, 0.5mm, 0.6mm or 1.0mm, etc.

[0214] In summary, the manufacturing method of the solar cell module provided in this application has the following technical advantages (1) to (7).

[0215] (1) Significantly improves the alignment accuracy between the conductive wire and the first grid line. For example, in the embodiments of this application, the conductive wire is spirally wound and the target placement angle of the battery cell is dynamically corrected, which can reduce the landing point error of the conductive wire to within ±0.15mm, or even within ±0.05mm.

[0216] (2) The number of main grids is not limited. For example, in the embodiments of this application, a single conductive wire can be wound to cover all the first grid lines. There are no physical constraints on the width of the solder head and the supply channel of the conductive wire. It can easily support a high-density grid line design with ≥30 first grid lines, so as to leave enough room for improving the efficiency of solar cell modules.

[0217] (3) Effectively reduces series resistance and power loss. For example, in the embodiments of this application, there is no need for insulating adhesive isolation and metal solder backfilling, which can ensure that the solder joint interface between the conductive wire and the first gate line is single and dense, thereby reducing series resistance and power loss.

[0218] (4) The welding process is simplified and the production cycle is improved. The embodiments of this application reduce the production process from three steps of "printing adhesive-curing-solder reflow" to one step of continuous wire winding welding, which can improve the production cycle and reduce BOM cost and energy consumption at the same time.

[0219] (5) No need for insulating adhesive isolation and metal solder compensation. For example, in the embodiments of this application, the conductive wire can be wound above the first grid line with high precision, which effectively reduces or eliminates the risk of cross-contact of the conductive wire, eliminating the need for printing polymer insulating adhesive and eliminating the need for a secondary metal solder backfilling process due to the step difference of the insulating adhesive.

[0220] (6) Enhanced long-term reliability of the battery string. In this embodiment, there is no organic adhesive volatilization or secondary heterogeneous solder joints, resulting in better thermo-mechanical matching of the welding interface. Furthermore, the current density of the conductive wire can be reduced due to the increased number of first grid lines, thus reducing the risk of hot spots.

[0221] (7) More environmentally friendly and safer. In the embodiments of this application, solvent-based insulating adhesive is not required, which can avoid the emission pollution of volatile organic compounds (VOCs) and the treatment of workshop odor; no metal solder compensation is required, which reduces the amount of solder used and can reduce the potential exposure of metals such as lead and bismuth.

[0222] Based on the same inventive concept, some embodiments of this application also provide a solar cell module, which can be prepared using the manufacturing methods for solar cell modules described in the above embodiments. This solar cell module also possesses all the technical advantages of the aforementioned manufacturing methods for solar cell modules.

[0223] In some embodiments of this application, please refer to Figure 5 and Figure 6 The solar cell module includes a cell string and multiple sub-conductive wires. The cell string includes multiple solar cells 11 arranged sequentially in a first direction. Each solar cell 11 has multiple first grid lines 111. The multiple first grid lines 111 extend along the first direction and are spaced apart in a second direction, which is orthogonal to the first direction. Sub-conductive wires are welded to the first grid lines 111 covered by the sub-conductive wires.

[0224] Here, the sub-conductive wire is formed by cutting the conductive wire 12; that is, the sub-conductive wire is the pattern-retained portion of the conductive wire 12. Furthermore, the sub-conductive wire and the first gate line 111 are metallized and welded together by heating, without the need for additional metal solder.

[0225] In some embodiments of this application, the maximum offset between the center line of the sub-conductive wire and the center line of the first gate line 111 is no greater than 0.05 mm.

[0226] In some embodiments of this application, multiple first grid lines 111 in the same battery cell 11 are arranged at equal intervals in a second direction.

[0227] Optionally, the spacing X between adjacent first grid lines 111 in the same solar cell 11 can range from 1.5mm ± 0.1mm to 8mm ± 0.1mm. This embodiment of the application can improve the manufacturing precision of the first grid line 111 to ±0.1mm, i.e., sub-millimeter level.

[0228] In some embodiments of this application, the width of the sub-conductive wire is ≥0.1mm; for example, it can be 0.1mm, 0.2mm, 0.3mm, 0.5mm, 0.6mm or 1.0mm, etc.

[0229] In some embodiments of this application, the product of the spacing X between adjacent first grid lines 111 in the same battery cell 11 and the number of first grid lines 111 in the battery cell 11 minus one is no greater than 230mm.

[0230] In some embodiments of this application, each battery cell 11 in the battery string has the same number of first grid lines 111, and the number of first grid lines 111 in each battery cell 11 ranges from 30 to 120; for example, it can be 30, 40, 50, 60, 80, 100 or 120.

[0231] In some embodiments of this application, please refer to Figure 14 It is understood that the solar cell 11 is provided with multiple second grid lines 112 connected to each first grid line 111. The multiple second grid lines 112 extend along a second direction and are arranged at intervals in a first direction, for example, they can be arranged at equal intervals. In the same solar cell 11, the second grid lines 112 connected to any two adjacent first grid lines 111 are staggered in the first direction. Taking the second grid line 112 connected to any first grid line 111 as a first group of grid lines U1, and the second grid lines 112 connected to two adjacent first grid lines 111 as a second group of grid lines U2 and a third group of grid lines U3, respectively, the second grid lines 112 in the second group of grid lines U2 and the second grid lines 112 in the third group of grid lines U3 are aligned in the first direction, and the spacing D between two relative second grid lines 112 in the second group of grid lines U2 and the third group of grid lines U3 is ≥0.2mm.

[0232] For example, the second group of grid lines U2 and the third group of grid lines U3 are grid lines of the same polarity. Both the second group of grid lines U2 and the third group of grid lines U3 are grid lines of opposite polarity to the first group of grid lines U1. In this embodiment, the spacing D between the two relative second grid lines 112 in the second group of grid lines U2 and the third group of grid lines U3 is ≥0.2mm, which can balance the current carrying capacity of the battery string with the insulation isolation capability between the sub-conductive wires and the opposite polarity second grid lines.

[0233] For example, the cell 11 is a back-contact (BC) cell, the first grid line 111 is the main grid (busbar), and the second grid line 112 is the fine grid (finger).

[0234] For example, the cell 11 is also provided with a plurality of bus pads (PADs) for connecting the first grid line 111 and / or the second grid line 112, respectively.

[0235] Please refer to some embodiments of this application. Figures 14-16 The solar cell 11 has multiple second grid lines 112 connected to each of the first grid lines 111. The multiple second grid lines 112 extend along a second direction and are spaced apart in the first direction. The solar cell module also includes an encapsulating adhesive layer 13 for encapsulating the cell string.

[0236] Optionally, the sub-conductive filament 121 is isolated from the second gate line 112 connected to the adjacent first gate line 111 by an encapsulating adhesive layer 13.

[0237] Optionally, the sub-conducting wire 121 is isolated from the second gate line 112 connected to the adjacent first gate line 111 by an air gap G.

[0238] As can be understood from the above, the sub-conducting wire 121 is only connected to the first gate line 111 of the same pole. No polymer insulating layer is required between the sub-conducting wire 121 and the adjacent second gate line 112 of the opposite pole; they can be isolated by the encapsulation layer 13 or the air gap G after encapsulation.

[0239] In the description of this specification, references to terms such as "some embodiments," "some examples," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0240] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0241] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application.

Claims

1. A method for manufacturing a solar cell module, characterized in that, include: A rotatable carrier is provided for matching a battery string to be welded; wherein the battery string to be welded includes: a plurality of battery cells arranged sequentially in a first direction; the battery cells are provided with a plurality of first grid lines; the plurality of first grid lines extend along the first direction and are spaced apart in a second direction; the second direction is orthogonal to the first direction; The circumferential dimension of the rotatable carrier is obtained, and based on the circumferential dimension and the distance between two adjacent target first grid lines in the battery cell, the target placement angle of the battery cell when it is placed along the circumference of the rotatable carrier is determined. The battery cells are placed on the rotatable carrier at the target placement angle; The conductive wire is spirally wound around the first grid line of each of the battery cells along the circumference of the rotatable carrier. The conductive wire and the first grid line are welded together to form a battery string.

2. The method for manufacturing a solar cell module according to claim 1, characterized in that, The rotatable carrier includes a cylindrical roller; determining the target placement angle of the battery cell when it is placed along the circumference of the rotatable carrier, based on the circumferential dimension and the spacing between two adjacent target first grid lines in the battery cell, includes: The spacing between two adjacent target first grid lines is defined as X, the circumferential dimension is Y, and the first included angle is θ1; The first included angle is determined according to the formula: θ1=arcsin(X / Y); Wherein, the target placement angle is equal to the first included angle.

3. The method for manufacturing a solar cell module according to claim 2, characterized in that, The spacing between two adjacent target first grid lines ranges from 1.5mm ± 0.1mm to 8mm ± 0.1mm.

4. The method for manufacturing a solar cell module according to claim 3, characterized in that, The width of the conductive wire is ≥0.1mm.

5. The method for manufacturing a solar cell module according to claim 2, characterized in that, The product of the spacing between two adjacent target first grid lines in the same battery cell and the number of first grid lines in the battery cell minus one is not greater than 230mm.

6. The method for manufacturing a solar cell module according to claim 2, characterized in that, The number of first grid lines in each of the battery cells in the battery string to be welded is the same, and the number of first grid lines in each of the battery cells ranges from 30 to 120.

7. The method for manufacturing a solar cell module according to claim 2, characterized in that, 0° ≤ absolute value of the target placement angle ≤ 1°; Alternatively, the absolute value of the target placement angle may range from 0.051° to 0.638°.

8. The method for manufacturing a solar cell module according to claim 1, characterized in that, The battery cell is provided with a first mark point and a second mark point spaced apart along the first direction; determining the target placement angle of each battery cell when it is placed along the circumference of the rotatable carrier based on the circumferential dimension and the spacing between two adjacent target first grid lines in the battery cell includes: The spacing between two adjacent target first grid lines is defined as X, the circumferential dimension as Y, and the first included angle as θ1; the first included angle is determined according to the formula: θ1=arcsin(X / Y); The battery cells are placed on the rotatable carrier at the first included angle; The first distance from the first marker point to the reference baseline, the second distance from the second marker point to the reference baseline, and the third distance between the first marker point and the second marker point are obtained respectively, and a first correction angle is determined based on the first distance, the second distance, and the third distance; The target placement angle is determined based on the first included angle and the first correction angle.

9. The method for manufacturing a solar cell module according to claim 8, characterized in that, Determining the first correction angle based on the first distance, the second distance, and the third distance includes: Define the first distance as d1, the second distance as d2, the third distance as d3, the second included angle as θ2, and the first correction angle as Δθ1; Determine the second included angle using the formula θ2 = arcsin [(d1-d2) / d3]; The first correction angle is determined according to the formula Δθ1=θ1 - θ2; Wherein, the target placement angle is equal to the sum of the first included angle and the first correction angle.

10. The method for manufacturing a solar cell module according to claim 1, characterized in that, The battery cell is provided with a plurality of second grid lines that are respectively connected to each of the first grid lines; the plurality of second grid lines extend along the second direction and are arranged at intervals in the first direction; After welding the conductive wire and the first grid line to form a battery string, the manufacturing method of the solar cell module further includes: Determine the first gate line to be tested, and select two target second gate lines from each of the second gate lines connected to the first gate line to be tested; The endpoint positions of the two target second gate lines located on the same side of the corresponding conductive wire are obtained and defined as the first endpoint position and the second endpoint position, respectively. The fourth distance from the first endpoint position to the corresponding conductive wire, the fifth distance from the second endpoint position to the corresponding conductive wire, and the sixth distance between the first endpoint position and the second endpoint position are obtained respectively, and a second correction angle is determined based on the fourth distance, the fifth distance, and the sixth distance; The target placement angle of the cells in the next battery string to be welded is updated based on the second correction angle.

11. The method for manufacturing a solar cell module according to claim 10, characterized in that, Determining the second correction angle based on the fourth distance, the fifth distance, and the sixth distance includes: The fourth distance is defined as d4, the fifth distance as d5, the sixth distance as d6, and the second correction angle as Δθ2; The second correction angle is determined according to the formula Δθ2 = arcsin [(d5-d4) / d6]. Wherein, the target placement angle of the battery cells in the next battery string to be welded is equal to the sum of the target placement angle of the battery cells in the current battery string to be welded and the second correction angle.

12. The method for manufacturing a solar cell module according to claim 10, characterized in that, The determination of the first gate line to be tested includes: Multiple detection areas are divided on the battery cell. Within each detection area, a preset number of the first grid lines are randomly selected or selected according to a preset rule as the first grid lines to be tested. The step of updating the target placement angle of the battery cells in the next battery string to be welded based on the second correction angle includes: updating the target placement angle of the battery cells in the next battery string to be welded based on the average value of the second correction angle corresponding to each of the first grid lines to be tested.

13. The method for manufacturing a solar cell module according to claim 10, characterized in that, The step of determining the first grid line to be tested includes: selecting the first grid line to be tested in a key area of ​​the battery cell; wherein, the key area includes: the starting area or the middle area of ​​the arrangement of each first grid line along the winding direction of the conductive wire.

14. The method for manufacturing a solar cell module according to claim 1, characterized in that, The matching battery string to be welded is provided with a rotatable carrier, including: Obtain the unfolded length of the battery string to be welded in the first direction; The target perimeter is determined based on the unfolded length; the target perimeter is greater than or equal to the unfolded length; A rotatable vehicle with a perimeter equal to the target perimeter is provided.

15. A method for manufacturing a solar cell module according to any one of claims 1 to 14, characterized in that, After the conductive wire is spirally wound around the first grid line of each of the solar cells, and before the conductive wire and the first grid line are welded, the method for manufacturing the solar cell module further includes: A curable adhesive is applied to multiple areas of the structure obtained after winding the conductive wire; wherein the areas to be coated extend along the second direction, and the multiple areas to be coated are spaced apart in the first direction; The curable adhesive is cured to form a cured adhesive strip; the cured adhesive strip is used to fix the conductive wire and the battery cell.

16. The method for manufacturing a solar cell module according to claim 15, characterized in that, The curing process of the curable adhesive includes photocuring or thermocuring.

17. The method for manufacturing a solar cell module according to claim 16, characterized in that, The curing process of the curable adhesive is a thermosetting process; wherein, The heating temperature range for the thermosetting process includes 100℃ to 300℃. The heating time for the thermosetting process ranges from 1 min to 60 min.

18. A method for manufacturing a solar cell module according to any one of claims 1 to 14, characterized in that, The welding of the conductive wire and the first grid line to form a battery string includes: The resulting structure after the conductive wire is wound around it is placed in a heating environment; The conductive wire is heated in the heating environment to weld it to the first grid line to form the battery string.

19. The method for manufacturing a solar cell module according to claim 18, characterized in that, The heating environment provides a heating temperature range of 100℃ to 500℃.

20. The method for manufacturing a solar cell module according to claim 18, characterized in that, The conductive wire includes photovoltaic solder ribbon.

21. A method for manufacturing a solar cell module according to any one of claims 1 to 14, characterized in that, Also includes: The conductive wire is patterned to form multiple sub-conductive wires.

22. The method for manufacturing a solar cell module according to claim 21, characterized in that, Also includes: The battery string is encapsulated by applying an encapsulating adhesive layer. The battery cell has multiple second grid lines that are respectively connected to each of the first grid lines; the multiple second grid lines extend along the second direction and are spaced apart in the first direction; the sub-conductive wires are isolated from the second grid lines connected to the adjacent first grid lines by the encapsulating adhesive layer or by an air gap.

23. The method for manufacturing a solar cell module according to any one of claims 1 to 14, characterized in that, The maximum offset between the centerline of the conductive wire and the centerline of the first gate line is no greater than 0.15 mm.

24. A solar cell module, characterized in that, include: A battery string includes: a plurality of battery cells arranged sequentially in a first direction; each battery cell has a plurality of first grid lines; the plurality of first grid lines extend along the first direction and are spaced apart in a second direction; the second direction is orthogonal to the first direction; Multiple sub-conductive wires; the sub-conductive wires are welded to the first grid line covered by the sub-conductive wires; The battery cell is provided with a plurality of second grid lines that are respectively connected to each of the first grid lines; the plurality of second grid lines extend along the second direction and are arranged at intervals in the first direction; In the same solar cell, the second grid lines connected to any two adjacent first grid lines are staggered in the first direction; the second grid lines connected to any first grid line are the first group of grid lines, and the second grid lines connected to the two adjacent first grid lines are the second group of grid lines and the third group of grid lines, respectively. The second grid lines in the second group of grid lines and the second grid lines in the third group of grid lines are aligned in the first direction, and the spacing between two relative second grid lines in the second group of grid lines and the third group of grid lines is ≥0.2mm.

25. The solar cell module according to claim 24, characterized in that, The solar cell module further includes: an encapsulating adhesive layer for encapsulating the solar cells; the sub-conductive wire is isolated from the second grid line connected to the adjacent first grid line by the encapsulating adhesive layer or by an air gap.

26. The solar cell module according to claim 24, characterized in that, The maximum offset between the centerline of the sub-conductive wire and the centerline of the first gate line is no greater than 0.15 mm.

27. The solar cell module according to claim 24, characterized in that, The spacing between adjacent first grid lines in the same solar cell ranges from 1.5mm ± 0.1mm to 8mm ± 0.1mm.

28. The solar cell module according to claim 26 or 27, characterized in that, The width of the sub-conductive wire is ≥0.1mm.

29. The solar cell module according to claim 24, characterized in that, The product of the spacing between adjacent first grid lines in the same battery cell and the number of first grid lines in the battery cell minus one is not greater than 230 mm.

30. The solar cell module according to claim 24, characterized in that, The number of first grid lines in each of the battery cells in the battery string is the same, and the number of first grid lines in each of the battery cells ranges from 30 to 120.

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