Solar cell module and manufacturing method thereof

Abstract

The invention relates to a solar cell module and a manufacturing method thereof. The method comprises the steps that a to-be-welded battery string is matched, and a rotatable carrier is provided; the battery string to be welded comprises a plurality of battery pieces which are sequentially arranged in the first direction, a plurality of first grid lines are arranged on the battery pieces, the first grid lines extend in the first direction and are arranged at intervals in the second direction, and the second direction is orthogonal to the first direction; acquiring the circumferential size of the rotatable carrier, and determining a target placement angle when the battery piece is placed along the circumferential direction of the rotatable carrier based on the circumferential size and the distance between two adjacent target first grid lines in the battery piece; placing the battery piece on a rotatable carrier according to the target placing angle; spirally winding a conductive wire on the first grid line of each battery piece along the circumferential direction of the rotatable carrier; and welding the conductive wires and the first grid lines to form a battery string. The method is used for realizing a high-precision, low-resistance and low-cost battery interconnection process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a solar cell module and a manufacturing method thereof. BACKGROUND

[0002] In recent years, with the continuous consumption of traditional energy, people's environmental awareness is also improving. As a clean energy, solar energy is attracting attention by directly converting light radiation into electrical energy through solar cells.

[0003] Back-contact (BC) cells are positioned as a "high-efficiency platform" route in the technical spectrum of crystalline silicon cells. All metal electrodes of the back-contact cell, such as busbars, fingers, and pads, are distributed on the back of the cell, which can ensure that the front of the cell is not blocked by metal, thereby increasing the effective light receiving area of the cell. The metal electrodes of the back-contact cell are usually arranged in an interdigital manner, and the current path can be formed by corresponding welding between the solder strip and the metal electrode.

[0004] However, with the continuous pursuit of solar cells in the photovoltaic industry in terms of high efficiency and low resistance loss, the spacing between the metal electrodes in the back-contact cell and the width of the solder strip are continuously reduced, which puts higher requirements on the precise welding of the solder strip. SUMMARY

[0005] Based on this, the embodiments of the present application provide a solar cell module and a manufacturing method thereof, which are beneficial to increase the number of grid lines, reduce the spacing between the grid lines, and improve the welding precision, thereby realizing 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 purpose, in one aspect, some embodiments of the present application provide a manufacturing method of a solar cell module, which can include the following steps:

[0007] Matching a to-be-welded cell string, and providing a rotatable carrier; wherein the to-be-welded cell string includes a plurality of cell pieces arranged in sequence in a first direction; the cell piece is provided with a plurality of first grid lines; the plurality of first grid lines extend along the first direction and are arranged at intervals in a second direction; the second direction is orthogonal to the first direction;

[0008] Obtaining the circumferential dimension of the rotatable carrier, and determining a target placement angle of the cell piece when 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 cell piece;

[0009] Placing the cell piece on the rotatable carrier according to the target placement angle;

[0010] The conductive wire is spirally wound on the first grid lines of each battery piece along a circumferential direction of the rotatable carrier.

[0011] The conductive wire and the first grid lines are welded to form the battery string.

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

[0013] Correspondingly, based on the circumferential dimension and the interval between the two adjacent target first grid lines in the battery piece, the target placement angle of the battery piece when placed along the circumferential direction of the rotatable carrier can be determined, which can comprise the following steps:

[0014] The interval between the two adjacent target first grid lines is defined as X, the circumferential dimension is Y, and the first included angle is θ1;

[0015] According to the formula: θ1=arcsin(X / Y), the first included angle is determined.

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

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

[0018] In some embodiments of the present application, the width of the conductive wire is greater than or equal to 0.1mm.

[0019] In some embodiments of the present application, the product of the interval between the two adjacent target first grid lines in the same battery piece and the number of first grid lines in the battery piece minus one is not greater than 230mm.

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

[0021] In some embodiments of the present application, the absolute value of the target placement angle ranges from 0° to 1°.

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

[0023] In some embodiments of the present application, the battery piece is provided with a first mark point and a second mark point arranged at intervals along a first direction. Based on the circumferential dimension and the interval between the two adjacent target first grid lines in the battery piece, the target placement angle of each battery piece when placed along the circumferential direction of the rotatable carrier can be determined, which can comprise the following steps:

[0024] Define the interval 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] Place the battery piece on the rotatable carrier according to the first included angle;

[0026] respectively obtain a first distance from the first mark point to the reference reference line, a second distance from the second mark point to the reference reference line, and a third distance between the first mark point and the second mark point, and determine a first correction angle based on the first distance, the second distance and the third distance;

[0027] Determine the target placement angle according to the first included angle and the first correction angle.

[0028] In some embodiments of the present application, determining the first correction angle based on the first distance, the second distance and the third distance can 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 according to the formula θ2 = arcsin [(d1-d2) / d3];

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

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

[0033] In some embodiments of the present application, a plurality of second grid lines are provided on the battery piece, each connected to a first grid line. The plurality of second grid lines extend in a second direction and are arranged at intervals in the first direction. After the soldering of the conductive wire and the first grid line to form the battery string, the method for manufacturing the solar cell module can further include the following steps:

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

[0035] Obtain the end point positions of the two target second grid lines on the same side of the corresponding conductive wire, respectively defined as the first end point position and the second end point position;

[0036] respectively obtain a fourth distance from the first end point position to the corresponding conductive wire, a fifth distance from the second end point position to the corresponding conductive wire, and a sixth distance between the first end point position and the second end point position, and determine a second correction angle based on the fourth distance, the fifth distance and the sixth distance;

[0037] Update the target placement angle of the cell tab in the next to-be-welded cell string based on the second correction angle.

[0038] In some embodiments of the present application, determining the second correction angle based on the fourth distance, the fifth distance and the sixth distance can 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] Determine the second correction angle according to the formula Δθ2= arcsin [(d5-d4) / d6];

[0041] Wherein, the target placement angle of the cell tab in the next to-be-welded cell string is equal to the sum of the target placement angle of the cell tab in the current to-be-welded cell string and the second correction angle.

[0042] In some embodiments of the present application, determining the to-be-tested first grid line can include the following steps:

[0043] Divide the cell tab into a plurality of detection areas,

[0044] Randomly or according to a preset rule, select a preset number of first grid lines in each detection area as to-be-tested first grid lines.

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

[0046] In some embodiments of the present application, determining the to-be-tested first grid line includes: selecting the to-be-tested first grid line in the key area of the cell tab; 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.

[0047] In some embodiments of the present application, matching the to-be-welded cell string, providing a rotatable carrier can include the following steps:

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

[0049] Determine the target circumference based on the unfolded length; the target circumference is greater than or equal to the unfolded length;

[0050] Provide a rotatable carrier with a circumference of the target circumference.

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

[0052] The obtained structure after winding the conductive wire is coated with a plurality of areas to be coated with curable glue; wherein, the areas to be coated with curable glue extend along the second direction, and the plurality of areas to be coated with curable glue are distributed at intervals in the first direction;

[0053] The curable glue is cured to form a cured glue strip; the cured glue strip is fixedly connected with the conductive wire and the battery piece.

[0054] In some embodiments of the present application, the curing process of the curable glue includes a light curing process or a thermal curing process.

[0055] In some embodiments of the present application, the curing process of the curable glue is a thermal curing process; wherein, the heating temperature of the thermal curing process ranges from 100℃ to 300℃; and the heating time of the thermal curing process ranges from 1min to 60min.

[0056] In some embodiments of the present application, the welding of the conductive wire and the first grid line to form the battery string includes: placing the obtained structure after winding the conductive wire in a heating environment; and heating the conductive wire based on the heating environment to weld the conductive wire with the first grid line to form the battery string.

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

[0058] In some embodiments of the present application, the conductive wire includes a photovoltaic solder strip.

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

[0060] In some embodiments of the present application, the manufacturing method of the solar cell module further includes: coating an encapsulation glue layer to encapsulate the battery string.

[0061] Optionally, the battery piece is provided with a plurality of second grid lines respectively connected with each first grid line. The plurality of second grid lines extend along the second direction and are arranged at intervals in the first direction; wherein, the sub-conductive wire and the second grid line connected with the adjacent first grid line are isolated by the encapsulation glue layer or by an air gap.

[0062] In some embodiments of the present application, the maximum offset between the center line of the conductive wire and the center line of the first grid line is not greater than 0.15mm.

[0063] In some embodiments of the present application, the solar cell module further comprises a plurality of second busbars on each cell piece, each second busbar being connected to a first busbar. The second busbars extend along the second direction and are arranged in the first direction with a spacing. The sub-conductive wire is isolated from the second busbars connected to the adjacent first busbars by the encapsulation layer or by an air gap.

[0064] In some embodiments of the present application, the solar cell module further comprises a plurality of second busbars on each cell piece, each second busbar being connected to a first busbar. The second busbars extend along the second direction and are arranged in the first direction with a spacing. The sub-conductive wire is isolated from the second busbars connected to the adjacent first busbars by the encapsulation layer or by an air gap.

[0065] In some embodiments of the present application, the maximum offset between the center line of the sub-conductive wire and the center line of the first busbar is not greater than 0.15 mm.

[0066] In some embodiments of the present application, the spacing between the adjacent first busbars in the same cell piece is in the range of 1.5 mm ± 0.1 mm to 8 mm ± 0.1 mm.

[0067] In some embodiments of the present application, the width of the sub-conductive wire is greater than or equal to 0.1 mm.

[0068] In some embodiments of the present application, the product of the spacing between the adjacent first busbars in the same cell piece and the number of first busbars in the cell piece minus one is not greater than 230 mm.

[0069] In some embodiments of the present application, the number of first busbars in each cell piece in the cell string is the same, and the number of first busbars in each cell piece is in the range of 30 to 120.

[0070] In some embodiments of the present application, the solar cell module further comprises a plurality of second busbars on each cell piece, each second busbar being connected to a first busbar. The second busbars extend along the second direction and are arranged in the first direction with a spacing. The sub-conductive wire is isolated from the second busbars connected to the adjacent first busbars by the encapsulation layer or by an air gap.

[0071] The embodiments of the present application can have / 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 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 A schematic view of a battery piece structure provided in some embodiments;

[0080] Figure 6 A schematic view of a target angle of a battery piece after circumferential expansion of a rotatable carrier provided in some embodiments;

[0081] Figure 7 A schematic view of a state of a robot placing a battery piece provided in some embodiments;

[0082] Figure 8 A schematic view of a second angle provided in some embodiments;

[0083] Figure 9 A schematic view of a state of winding a conductive wire provided in some embodiments;

[0084] Figure 10 A schematic view of a state of applying a curable adhesive provided in some embodiments;

[0085] Figure 11 A schematic view of a state of curing a curable adhesive provided in some embodiments;

[0086] Figure 12 A schematic view of a distribution of a cured adhesive strip provided in some embodiments;

[0087] Figure 13 A schematic view of a state of welding a conductive wire and a first grid line provided in some embodiments;

[0088] Figure 14 A schematic view of another battery piece structure provided in some embodiments;

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

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

[0091] Figure 17 A schematic view of a second correction angle provided in some embodiments.

[0092] BRIEF DESCRIPTION OF THE DRAWINGS

[0093] 10 - battery string to be welded, 11 - battery sheet, 111 - first grid line, 112 - second grid line, 12 - conductive wire, 121 - sub-conductive wire, 13 - encapsulation glue layer, G - air gap, 20 - rotatable carrier, 31 - mechanical hand, 40 - guiding mechanism, 50 - glue coating mechanism, 51 - cured glue 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 DESCRIPTION

[0094] For the purposes of this application, reference will be made to the accompanying drawings in which preferred embodiments of the application are shown. The application may, however, be carried out in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art.

[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 in the description of the application herein is for 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" or "connected to" another element or layer, it can be directly on or connected to the other element or layer or intervening elements or layers can be present. In addition, it should be understood that, when a term is used in the singular, it also includes the plural unless explicitly stated otherwise. Furthermore, to the extent that the terms "including", "includes", "having", "has", "with", or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term "comprising" as an open transition term without precluding any additional or other elements.

[0097] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It should also be understood that, unless clearly indicated to the contrary, the word "comprise", and variations such as "comprises" or "comprising", will be understood to include the words "consist of" or "consisting of".

[0098] Currently, with the continuous pursuit of high efficiency and low resistance loss of solar cells in the photovoltaic industry, the spacing between metal electrodes and the width of the solder strip in back contact cells are constantly shrinking, which puts higher requirements on the precision welding of the solder strip.

[0099] For example, each metal electrode of the back contact cell includes a plurality of main grids distributed in parallel and a plurality of fine grids distributed in a fishbone shape on both sides of the main grid, and the corresponding connected fine grids of adjacent main grids are staggered along the distribution direction. In this way, the current can be vertically injected from the fine grid to the main grid to shorten the horizontal transmission distance (i.e. shorten the current collection path) and reduce the series resistance loss. Optionally, adjacent main grids are opposite main grids, and the corresponding connected fine grids are opposite fine grids, i.e. positive fine grids and negative fine grids. On this basis, during the assembly interconnection stage of the back contact cell, once the solder strip has a slight horizontal drift when placed, it is likely to cross the opposite fine grids connected to the corresponding main grids on both sides, resulting in short circuit of the opposite fine grids.

[0100] In some examples, the automatic string welding equipment usually adopts a three-step method of "hovering-fitting-welding", which specifically includes the following steps: the robot moves the solder strip horizontally to the top of the target main grid; place the pressure net to realize the fitting of the solder strip and the cell bus pad; maintain the pressure and heating to complete the alloying welding. In this way, under the high-speed motion mode of the robot, the solder strip will be subjected to the coupling effect of the motion inertia (e.g. its horizontal component) and the fitting pressure (e.g. its vertical component) at the moment of pressing down, resulting in random deviation of the landing position of the solder strip. The existing production data and the applicant's verification have shown that even if the automatic string welding equipment is calibrated by servo closed loop, the placement error of the solder strip is not conducive to increasing the number of main grids, and there is a risk of short circuit when the center distance of the fine grid is small.

[0101] In some examples, the short circuit risk in the foregoing examples can be solved by adopting a combination scheme of "insulating adhesive isolation + metal solder compensation". For example, about 30 μm thick solvent-containing polymer insulating adhesive (such as an acrylic or epoxy system insulating adhesive) is deposited on the heteropolar fine grid by screen printing or inkjet deposition, so as to form a high dielectric strength barrier layer between the solder strip and the fine grid, thereby avoiding electrical short circuit. However, after curing, the insulating adhesive forms a step on the surface of the fine grid, that is, the height of the insulating adhesive is higher than the area not coated with the insulating adhesive, which destroys the coplanar contact of the solder strip and the main grid, and causes subsequent problems such as soldering gap, increased contact resistance, and decreased solder joint reliability. Therefore, the metal solder needs to be printed again in the soldering area and reflow soldering is performed, so that the solder fills the height difference caused by the insulating adhesive after flowing and solidifying, and is alloyed with the solder strip again. Although this restores the flat contact interface between the solder strip and the main grid, which is beneficial to ensure the soldering strength and electrical continuity, it also has many problems, such as: increasing the cost of metal paste and printing process, reflow process, and easily causing significant increase in manufacturing rhythm and bill of material (BOM cost); the residual interfacial compounds and pores of the second heterogeneous solder joint easily increase the series resistance and are prone to cause thermal fatigue and mechanical fatigue; solvent evaporation, solder shrinkage and multiple heating cycles easily cause inclusions, voids and odor emission, which bring risks of long-term reliability and environmental compliance.

[0102] In addition, it can be understood that increasing the number of main grids and reducing the distance between the main grids in the back contact cell can further reduce the current-carrying distance, significantly reduce the series resistance loss in the cell and improve the fill factor, so as to realize low-loss output under high current density and allow the use of thinner or narrower solder strips to save metal consumption and reduce thermal stress and mechanical stress. However, with the increase in the number of main grids and the reduction in the distance between the main grids, the existing series connection equipment will face a hardware space bottleneck, thereby limiting the development of high-density main grid technology.

[0103] Based on this, the embodiments of the present application provide a solar cell module and a manufacturing method thereof, which are beneficial to increase the number of grid lines, reduce the distance between the grid lines, and improve the soldering precision, so as to realize a high-precision, low-resistance and low-cost back contact cell interconnection process, and ensure and improve the production yield and long-term reliability of the solar cell module.

[0104] Please refer to Figure 1 Some embodiments of the present application provide a manufacturing method of a solar cell module, which can include the following steps S100-S500.

[0105] S100, matching a battery string to be welded, and providing a rotatable carrier; wherein the battery string to be welded comprises: a plurality of battery pieces arranged in sequence in a first direction; a plurality of first grid lines provided on the battery pieces; the plurality of first grid lines extend along the first direction and are arranged at intervals in a second direction; the second direction is orthogonal to the first direction.

[0106] S200, obtaining a circumferential dimension of the rotatable carrier, and determining a target placement angle of the battery pieces when placed along the circumference of the rotatable carrier based on the circumferential dimension and a spacing between two adjacent target first grid lines in the battery pieces.

[0107] Optionally, the rotatable carrier includes but is not limited to a cylindrical roller. The rotatable carrier can rotate at a uniform speed.

[0108] Optionally, the first grid lines are arranged at equal intervals in the second direction, and the target first grid lines 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 lines can be selected from the first grid lines in the key area according to requirements. For example, the battery piece includes a main area and an edge area, the spacing between adjacent first grid lines located in the main area is a first spacing, the spacing between adjacent first grid lines located in the edge area is a second spacing, and the first spacing and the second spacing are different; wherein the two adjacent target first grid lines can be any two first grid lines located in the main area.

[0110] S300, placing the battery pieces on the rotatable carrier according to the target placement angle.

[0111] Optionally, the target placement angle of each battery piece can be determined one by one.

[0112] Optionally, the structures of the battery pieces are the same, and the target placement angle of each battery piece can be placed according to the target placement angle of any one battery piece.

[0113] Optionally, the rotatable carrier can vacuum adsorb the battery pieces to realize the placement and fixation of the battery pieces on the rotatable carrier.

[0114] S400, spirally winding a conductive wire on the first grid lines of each battery piece along the circumference of the rotatable carrier.

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

[0116] Optionally, the conductive wire includes but is not limited to a photovoltaic welding strip.

[0117] In the embodiments of the present application, the rotatable carrier capable of matching the battery string to be welded is provided, and the target placement angle of the battery piece when placed along the circumference of the rotatable carrier is determined according to the circumferential size of the rotatable carrier and the spacing between the two adjacent target first grid lines in the battery piece. Then, the battery piece is placed on the rotatable carrier according to the target placement angle, so that the single conductive wire can be spirally wound on the first grid line of each battery piece along the circumference of the rotatable carrier, the alignment of the conductive wire and the first grid line is realized, and the subsequent welding of the conductive wire and the first grid line is performed, so as to obtain the battery string. The embodiments of the present application can establish a reference coordinate system based on the rotatable carrier, and realize the welding between the conductive wire and the first grid line by the way of pre-determining the target placement angle, placing the battery piece according to the target placement angle, and self-aligning and winding the conductive wire, which is beneficial to realize the size alignment of the conductive wire relative to the first grid line in the sub-millimeter level, effectively eliminate the inertial deviation caused by the high-speed back-and-forth placement of the mechanical hand for multiple conductive wires, and does not need to be isolated by the insulating glue and compensated by the metal solder, thereby being beneficial to increase the number of the first grid lines, reduce the spacing between the first grid lines, improve the welding precision, and further realize the high-precision, low-resistance and low-cost battery interconnection process, and ensure and improve the production yield and long-term reliability of the solar cell module.

[0118] In some embodiments of the present application, referring to Figure 2 , the manufacturing method of the solar cell module further includes step S600.

[0119] S600, patterning the conductive wire to form a plurality of sub-conductive wires.

[0120] Here, the connection relationship between the sub-conductive wire and the first grid line can be patterned to divide the conductive wire into a plurality of sub-conductive wires.

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

[0122] In the embodiments of the present application, after the single conductive wire is spirally wound on the first grid line of each battery piece and the conductive wire is welded with the first grid line, the plurality of sub-conductive wires can be obtained by cutting the conductive wire, which can avoid repeated conductive wire alignment and placement and welding procedures, and is beneficial to improve the production efficiency and production yield.

[0123] It should be noted that in some embodiments of the present application, the matching of the battery string to be welded in step S100 and the provision of the rotatable carrier can include steps S110-S130.

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

[0125] Here, the unfolded length of the battery string to be welded can be different due to different component types of the battery string to be welded.

[0126] Optionally, the unwound length of the battery string to be welded ranges from 728 mm to 1570 mm, for example, the unwound length can be 728 mm, 1176 mm or 1570 mm, etc.

[0127] In S120, a target circumference is determined based on the unwound length; the target circumference is greater than or equal to the unwound length.

[0128] In S130, a rotatable carrier with a circumference equal to the target circumference is provided.

[0129] In the embodiments of the present application, the rotatable carrier with a circumference greater than or equal to the unwound length of the battery string to be welded can be used to unwind and lay the battery string to be welded on the outer surface of the rotatable carrier in one direction, so that the first grid lines of each battery piece in the single battery string to be welded can be spirally wound by a single conductive wire.

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

[0131] It is worth mentioning that, in some embodiments, the material of the rotatable carrier is related to its moment of inertia. The above-mentioned target circumference can also be determined in combination with the unwound length of the battery string to be welded and the material of the rotatable carrier to more accurately select the rotatable carrier.

[0132] Optionally, the rotatable carrier is a cylindrical roller, and the material density of the cylindrical roller is greater than 7 g / cm 3 , for example, the material can be metal material such as stainless steel or aluminum alloy. In addition, the cylindrical roller can be a hollow roller or a solid roller.

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

[0134] In order to clearly show the manufacturing method of the solar cell module provided in the embodiments of the present application, Figure 3 an exemplary structural diagram of an automatic string welding device is provided. The implementation of the manufacturing method of the solar cell module is described in detail in some embodiments in combination with the device shown. Figure 3

[0135] Please refer to Figure 3 and Figure 4 ​At the loading station, the battery string 10 to be welded can be matched, the rotatable carrier 20 is provided, and after the target placement angle θ of the battery sheet 11 is determined, the battery sheet 11 is placed on the rotatable carrier 20 according to the target placement angle θ. The target placement angle θ of the battery sheet 11 can be determined in various ways.

[0136] In some embodiments of the present application, referring to Figure 5 and Figure 6 , the target placement angle of the battery sheet when placed along the circumference of the rotatable carrier can be determined based on the circumferential dimension and the spacing between the two adjacent target first grid lines in the battery sheet in step S200. It can include the following steps S210 and S220.

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

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

[0139] In some examples, as shown in the battery sheet 11, Figure 5 , the battery sheet 11 is provided with a plurality of first grid lines 111, which are arranged at equal intervals in the second direction, for example. Assuming that each battery sheet 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, as shown in Figure 6 , after the circumferential surface of the rotatable carrier 20 is unfolded, the conductive wire 12 is spirally wound on the first grid lines 111 of each battery sheet 11, and the conductive wire 12 can form a helical trajectory on the circumferential surface of the rotatable carrier 20 with a pitch X and an angle of rise θ, i.e. the winding pitch of the conductive wire 12 can be equal to the spacing between the adjacent first grid lines in the same battery sheet 11. And, Figure 6 , the positions of the two A points on the circumferential surface of the rotatable carrier 20 are the same when the circumferential surface is a cylindrical surface. Based on this, when the spacing between the 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 the present embodiment, the target placement angle θ is set to be equal to the first included angle θ1, which can ensure that a single conductive wire is aligned and wound between the first grid lines 111 on each battery sheet 11.

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

[0141] For example, the interval X between two adjacent target first grid lines 111 can be 1.4 mm, 1.5 mm, 1.6 mm, 1.9 mm, 2.0 mm, 2.1 mm, 4.9 mm, 5.0 mm, 5.1 mm, 7.9 mm, 8.0 mm, or 8.1 mm, etc. The manufacturing precision of the first grid lines 111 can be improved to ±0.1 mm, i.e., sub-millimeter level.

[0142] For example, the absolute value of the target placement angle can be in the range of 0° to 1°.

[0143] Here, the target placement angle can be positive or negative, depending on the placement direction of the battery piece 11 relative to the end face edge of the rotatable carrier 20. For example, the target placement angle can be positive when the battery piece 11 is placed clockwise relative to the end face edge of the rotatable carrier 20, and negative when the battery piece 11 is placed counterclockwise relative to the end face edge of the rotatable carrier 20.

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

[0145] In some examples, the rotatable carrier 20 is a cylindrical roller with a radius R = 375 mm, and the interval X between two adjacent target first grid lines in the same battery piece 11 is 8 mm. The target placement angle θ = θ1 = 0.389° can be calculated by the formula θ1 = arcsin (X / Y). Similarly, the target placement angle can be calculated based on the above formula for different values of the radius and the interval between two adjacent target first grid lines in the same battery piece 11.

[0146] In some embodiments of the present application, the product of the interval between two adjacent target first grid lines in the same battery piece and the number of first grid lines in the battery piece minus one is not greater than 230 mm.

[0147] Optionally, the number of first grid lines in each battery piece in the battery string to be welded is the same, and the number of first grid lines in each battery piece is in the range of 30 to 120, for example, 30, 40, 50, 60, 80, 100, or 120.

[0148] In some embodiments, please refer to Figure 3 and Figure 7It is understood that the battery piece 11 is usually placed on the rotatable carrier 20 by the robot mechanical arm 31. Specifically, the mechanical arm 31 generally places the battery piece 11 at the corresponding position by the position data of the visually positioned battery piece 11 and the position of the rotatable carrier 20. Then, the battery piece 11 is fixed by the rotatable carrier 20.

[0149] Here, it can be understood that, since the mechanical arm 31 and the rotatable carrier 20 usually have a small angle deviation when the battery piece is taken and positioned, in some embodiments of the present application, please refer to Figure 8 The first mark point Mark1 and the second mark point Mark2 can be arranged on the battery piece 11 along the first direction (i.e. the first grid line extension direction) to measure and determine the first correction angle based on the first mark point Mark1 and the second mark point Mark2, so as to compensate for the angle deviation when the mechanical arm 31 takes the battery piece and the rotatable carrier 20 is positioned. The shape, material and implementation form of the first mark point Mark1 and the second mark point Mark2 are not limited in the embodiments of the present application, and any shape, material and implementation form that can be measured and recognized is acceptable.

[0150] Correspondingly, the step S200 of determining the target placement angle of the battery piece when placed along the circumference of the rotatable carrier based on the circumferential dimension and the interval between the two adjacent target first grid lines in the battery piece can include the following steps S210'~S240'.

[0151] S210', define the interval between the two adjacent target first grid lines as X, the circumferential dimension of the rotatable carrier as Y, and the first included angle as θ1; and determine the first included angle θ1 according to the formula: θ1=arcsin(X / Y).

[0152] S220', place the battery piece on the rotatable carrier according to the first included angle.

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

[0154] Optionally, the reference reference line is a virtual straight line, the extension direction of the reference reference line is parallel to the axis of the rotatable carrier, and the reference reference line and 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 piece.

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

[0156] For example, as Figure 8As shown in FIG. 6, the step S230' of determining the first correction angle based on the first distance, the second distance and the third distance can include steps S231-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, determine the second included angle θ2 according to the formula θ2 = arcsin [(d1-d2) / d3].

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

[0160] Correspondingly, in the 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 the embodiment, after the solar cell is placed on the rotatable carrier according to the first included angle, the actual placement angle (i.e., the second included angle θ2) of the solar cell can be measured based on the first mark Mark1 and the second mark Mark2, so that the first correction angle Δθ1 can be determined based on Δθ1 = θ1- θ2. Thus, after the target placement angle θ is determined by compensating the first included angle θ1 according to the first correction angle Δθ1 (i.e., θ = θ1+ Δθ1), the actual placement angle of the solar cell can be the first included angle θ1 when the robot places the solar cell according to the target placement angle, so that the alignment between the single conductive wire and the first busbar 111 on each solar cell 11 can be ensured.

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

[0163] Please refer to Figure 3 and Figure 9 After the solar cells 11 are placed in the loading station, the obtained structure can be sequentially conveyed to the wire winding station. In the wire winding station, the single conductive wire 12 is first positioned at the starting point of the busbar of the rotatable carrier 20 by the solder strip clamping jaw, then the rotatable carrier 20 is controlled to rotate at a constant speed, the solder strip winding mechanism is controlled to move at a constant speed, and the conductive wire 12 can be wound on the first busbar of each solar cell 11 by the solder strip clamping jaw under the guidance of the guide mechanism 40. For example, the first busbars 111 in each solar cell 11 are arranged at equal intervals in the second direction, and the conductive wire 12 can form a helical trajectory with a pitch X and an angle θ on the circumferential surface of the rotatable carrier 20.

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

[0165] S410, after winding the conductive wire, the plurality of areas to be glued of the resulting structure are coated with a solidifiable glue; wherein the areas to be glued extend in the second direction, and the plurality of areas to be glued are distributed in the first direction.

[0166] Here, the number, position and gluing process of the areas to be glued can be matched with the requirements and set by adjusting the parameters.

[0167] For example, in combination with Figure 3 and Figure 10 It is understood that after the winding of the conductive wire 12 is completed, the resulting structure can be sequentially conveyed to the gluing station. At the gluing station, the solidifiable glue is applied to each area to be glued by the gluing mechanism 50. The solidifiable glue is a high-molecular fixed glue, which is used to fix the conductive wire after solidification to prevent the conductive wire from shifting position before welding.

[0168] S420, solidify the solidifiable glue to form a solidified glue strip; the solidified glue strip fixedly connects the conductive wire and the cell.

[0169] Optionally, the solidification process of the solidifiable glue includes a light solidification process or a heat solidification process.

[0170] In some examples, in combination with Figure 3 and Figure 11 It is understood that after gluing, the resulting structure can be sequentially conveyed to the light solidification station. At the light solidification station, the solidifiable glue is solidified to form a solidified glue strip by applying ultraviolet light through the curing lamp box 60.

[0171] In other examples, the solidification process of the solidifiable glue is a heat solidification process, which can be heated by infrared light, for example.

[0172] Optionally, the heating temperature of the heat solidification process ranges from 100°C to 300°C, for example, it can be 100°C, 150°C, 200°C or 300°C, etc.

[0173] In some examples, the heating temperature of the heat solidification process ranges from 120°C to 150°C, for example, it can be 120°C, 130°C, 140°C or 150°C, etc.

[0174] Optionally, the heating time of the heat solidification process ranges from 1 minute to 60 minutes, for example, it can be 1 minute, 5 minutes, 10 minutes, 30 minutes, 40 minutes, 50 minutes or 60 minutes, etc.

[0175] In some examples, the heating duration of the heat curing process can range from 10 minutes to 30 minutes, for example, can be 10 minutes, 15 minutes, 20 minutes, 25 minutes or 30 minutes, etc.

[0176] For example, as shown in Figure 12 The extension direction of the cured adhesive strip 51 is perpendicular to the extension direction of the conductive wire 12. At least two cured adhesive strips 51 can be formed on each coil of the conductive wire 12.

[0177] In some embodiments of the present application, the step S500 of welding the conductive wire and the first grid line to form the battery string can include the following steps S510 and S520.

[0178] S510, placing the resulting structure after winding the conductive wire in a heating environment.

[0179] For example, please understand Figure 3 and Figure 13 After fixing the conductive wire 12, the resulting structure can be sequentially conveyed to the welding station. In the welding station, the heating environment can be provided by controlling the infrared lamp box 70 to heat.

[0180] S520, heating the conductive wire based on the heating environment to weld the conductive wire and the first grid line to form the battery string.

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

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

[0183] In some examples, the heating temperature provided by the heating environment can range from 150°C to 250°C, for example, can be 150°C, 180°C, 200°C, 220°C or 250°C, etc.

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

[0185] From the above, please understand Figure 3 After welding the conductive wire and the first grid line, the resulting structure can be sequentially conveyed to the discharging station to remove the battery string in the discharging station.

[0186] Based on the above, the manufacturing method of the solar cell module provided by the embodiments of the present application can be based on Figure 3 The automatic string welding equipment shown in the figure is completed by station circulation. After the workbench in the automatic string welding equipment is rotated to the designated station, the corresponding structure is automatically triggered to perform the work.

[0187] In some embodiments, the patterning process of the conductive wire is performed after the cell string is taken out at the cutting station.

[0188] In some embodiments, referring to Figure 2 , the manufacturing method of the solar cell module further includes the following step S700.

[0189] S700, coating an encapsulation adhesive layer to encapsulate the cell string.

[0190] Optionally, in combination with Figure 14 and Figure 15 , it is understood that the solar cell sheet 11 is provided with a plurality of second grid lines 112 connected to each first grid line 111 respectively. The plurality of second grid lines 112 extend in the second direction and are arranged at intervals in the first direction. The sub-conductive wire 121 after the patterning of the conductive wire is isolated from the second grid line 112 connected to the adjacent first grid line 111 by the encapsulation adhesive layer 13.

[0191] Optionally, in combination with Figure 14 and Figure 16 , it is understood that the sub-conductive wire 121 after the patterning of the conductive wire is isolated from the second grid line 112 connected to the adjacent first grid line 111 by the air gap G.

[0192] It should be noted that after the welding of the conductive wire and the first grid line to form the cell string in step S500, due to the position tolerance between the surface coating (such as Teflon tape) of the rotatable carrier and different mechanisms inside the automatic string welding equipment, a stable system angle deviation is easily introduced in the cell string, and the system angle deviation is related to the target placement angle of the solar cell sheet, that is, the system angle deviation is relatively stable at the same solar cell sheet placement position. Based on this, in some embodiments of the present application, referring to Figure 14 , the solar cell sheet 11 is provided with a plurality of second grid lines 112 connected to each first grid line 111 respectively. The plurality of second grid lines 112 extend in the second direction (i.e., the second grid line 112 is perpendicular to the first grid line 111), and are arranged at intervals in the first direction, for example, at equal intervals. Each second grid line 112 can be, for example, an equal-length grid line. The manufacturing method of the solar cell module can further include the following steps S710-S740.

[0193] S710, determining a to-be-tested first grid line, and selecting two target second grid lines from the second grid lines connected to the to-be-tested first grid line.

[0194] S720, obtaining end point positions of the two target second grid lines on the same side of the corresponding conductive wire, which are defined as a first end point position and a second end point position, for example Figure 17 end point 1 and end point 2 shown in FIG. 7B.

[0195] S730, obtaining a fourth distance from the first end point position to the corresponding conductive wire, a fifth distance from the second end point position to the corresponding conductive wire, and a sixth distance between the first end point position and the second end point position, and determining a second correction angle based on the fourth distance, the fifth distance, and the sixth distance.

[0196] S740, updating the target placement angle of the cell tab in the next to-be-welded cell string based on the second correction angle.

[0197] In some embodiments of the present application, referring to Figure 17 , the step S730 of determining the second correction angle based on the fourth distance, the fifth distance, and the sixth distance can include the following steps S731 and S732.

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

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

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

[0201] It can be understood that, in combination with the related descriptions in some of the foregoing embodiments, when the target placement angle θ of the cell tab in the current to-be-welded cell string is θ1, the target placement angle θ' of the cell tab in the next to-be-welded cell string is θ1+ Δθ2. When the target placement angle θ of the cell tab in the current to-be-welded cell string is θ1+ Δθ1, the target placement angle θ' of the cell tab in the next to-be-welded cell string is θ1+ Δθ1+ Δθ2.

[0202] In the embodiments of the present application, after the welding is completed and the to-be-measured first grid line and the two target second grid lines are determined, the second correction angle Δθ2 can be determined based on the distances from the end point positions of the two target second grid lines on the same side of the corresponding conductive wire, that is, end point 1 and end point 2 to the conductive wire. Please refer to Figure 17It is understood that the second correction angle Δθ2 can effectively represent the relative deflection between the first grid line 111 and the conductive wire 12 under the influence of the system angle deviation. Thus, according to the second correction angle Δθ2, the target placement angle θ' of the cell in the next to be welded cell string is compensated, which can effectively compensate the system angle deviation in the process of the next to be welded cell string, thereby further improving the alignment accuracy between the conductive wire and the first grid line 111.

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

[0204] In addition, the determination of the to-be-measured first grid line in the step S710 can be implemented by the following two implementation manners.

[0205] In some embodiments of the present application, the area average method can be used to determine the to-be-measured first grid line. For example, the determination of the to-be-measured first grid line in the step S710 can include the following steps S711 and S712.

[0206] S711, dividing a plurality of detection areas on the cell.

[0207] S712, selecting a preset number of first grid lines in each detection area as to-be-measured first grid lines at random or according to a preset rule.

[0208] Correspondingly, in the step S740, updating the target placement angle of the cell in the next to be welded cell string based on the second correction angle can be manifested as: updating the target placement angle of the cell in the next to be welded cell string based on the average value of the second correction angle corresponding to each to-be-measured first grid line. That is, in the embodiment in which the to-be-measured first grid line is multiple, the second correction angle corresponding to each to-be-measured first grid line can be obtained one by one, and then the average value of each second correction angle is calculated to update the target placement angle of the cell in the next to be welded cell string based on the average value of each second correction angle.

[0209] In some embodiments of the present application, the first grid line to be measured can be determined by a specific position method. For example, in step S710, the first grid line to be measured can be determined by selecting the first grid line to be measured in a key area of the battery piece. The key area includes a starting area or a middle area of the first grid lines arranged along the winding direction of the conductive wire. That is, along the winding direction of the conductive wire, the first grid line at the starting area or one or more first grid lines at the middle area can be selected as the first grid line to be measured. It can be understood that in the example where the first grid line is multiple, the second correction angle can be the average of the second correction angles corresponding to each first grid line to be measured.

[0210] From the above, the embodiments of the present application can converge the landing point error of the conductive wire to within ±0.15 mm by dynamically iterating the target placement angle of the battery piece. That is, the maximum offset between the center line of the conductive wire and the center line of the first grid line is not greater than 0.15 mm.

[0211] In some examples, the landing point error of the conductive wire can be converged 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 not greater than 0.10 mm.

[0212] In some examples, the landing point error of the conductive wire can be converged 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 not greater than 0.05 mm.

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

[0214] In summary, the manufacturing method of the solar cell module provided by the embodiments of the present application can have the following technical advantages (1)~(7).

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

[0216] (2) The number of main grids is not limited. For example, in the embodiments of the present application, a single conductive wire can be wound to cover all the first grid lines, without the physical constraints of the width of the solder head and the conductive wire supply channel, which can easily support a high-density grid line design of ≥30 first grid lines, leaving enough space for the efficiency improvement of the solar cell module.

[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 the present application, the maximum offset between the center line of the sub-conductive wire and the center line of the first grid line 111 is not greater than 0.05 mm.

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

[0227] Optionally, the interval X between adjacent first grid lines 111 in the same cell 11 is in the range of 1.5 mm ± 0.1 mm to 8 mm ± 0.1 mm. The embodiments of the present application can improve the manufacturing precision of the first grid line 111 to ± 0.1 mm, i.e., sub-millimeter level.

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

[0229] In some embodiments of the present application, the product of the interval X between adjacent first grid lines 111 in the same cell 11 and the number of first grid lines 111 in the cell 11 minus one is not greater than 230 mm.

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

[0231] In some embodiments of the present application, please refer to Figure 14 It is understood that the cell 11 is provided with a plurality of second grid lines 112 connected to each first grid line 111 respectively. The plurality of second grid lines 112 extend in the second direction and are arranged at intervals in the first direction, for example, at equal intervals. Among them, in the same cell 11, each second grid line 112 connected by any two adjacent first grid lines 111 is arranged in staggered arrangement in the first direction. The second grid line 112 connected by any first grid line 111 is the first group of grid lines U1, and the second grid lines 112 connected by the two first grid lines 111 adjacent to the first grid line 111 are the second group of grid lines U2 and the 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 arranged in alignment in the first direction, and the interval D between the two second grid lines 112 in the second group of grid lines U2 and the third group of grid lines U3 is ≥ 0.2 mm.

[0232] For example, the second group of grid lines U2 and the third group of grid lines U3 are homopolar grid lines. The second group of grid lines U2 and the third group of grid lines U3 are all heteropolar grid lines with the first group of grid lines U1. In the embodiment of the present application, the distance D between the opposite two second grid lines 112 in the second group of grid lines U2 and the third group of grid lines U3 is greater than or equal to 0.2 mm, which can take into account the current carrying capacity of the battery string and the insulation isolation capacity between the sub-conductive wires and the heteropolar second grid lines.

[0233] For example, the battery piece 11 is a back contact (BC for short) battery piece, the first grid line 111 is a busbar, and the second grid line 112 is a finger.

[0234] For example, the battery piece 11 is further provided with a plurality of pad welding pads for connecting the first grid line 111 and / or the second grid line 112.

[0235] In some embodiments of the present application, referring to Figures 14-16 The battery piece 11 is provided with a plurality of second grid lines 112 connected with each first grid line 111. The plurality of second grid lines 112 extend along the second direction and are arranged at intervals in the first direction. The solar cell module further comprises an encapsulation adhesive layer 13 encapsulating the battery string.

[0236] Optionally, the sub-conductive wire 121 and the second grid line 112 connected with the adjacent first grid line 111 are isolated by the encapsulation adhesive layer 13.

[0237] Optionally, the sub-conductive wire 121 and the second grid line 112 connected with the adjacent first grid line 111 are isolated by the air gap G.

[0238] From the above, it can be understood that the sub-conductive wire 121 is only in contact with the homopolar first grid line 111. The sub-conductive wire 121 and the adjacent heteropolar second grid line 112 do not need to be provided with any polymer insulating adhesive layer, and can be isolated by the encapsulation adhesive layer 13 or the air gap G after encapsulation.

[0239] In the description of the specification, the description of the terms "some embodiments", "some examples", "exemplarily", and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are contained in at least one embodiment or example of the present application. In the specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example.

[0240] The technical features of the above embodiments can be combined in any manner. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the present application.

[0241] The above embodiments only express several implementation ways of the present application, and the description is more specific and detailed, but it should not be understood as a limitation to the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the scope of protection of the present 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 as Y, and the first included angle as 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 battery cell 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.

25. The solar cell module according to claim 24, characterized in that, The battery cell has multiple second grid lines 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; wherein, The solar cell module further includes: an encapsulating adhesive layer that encapsulates the solar cells; The sub-conductive wire is isolated from the second gate line connected to the adjacent first gate 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.

31. The solar cell module according to claim 24, 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; 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.

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