A solar cell string and a battery module

Abstract

This utility model relates to the field of solar photovoltaic technology, and particularly to a solar cell string and a solar cell module. In the solar cell string, adjacent cells are connected by multiple conductive connectors; at least one side of each cell has multiple grid lines; each conductive connector includes at least one first sub-connector and multiple second sub-connectors, spaced apart along the extension direction of the conductive connector, each second sub-connector being electrically connected to multiple grid lines; the first sub-connector is disposed between two adjacent second sub-connectors and is electrically connected to each of the two adjacent second sub-connectors. When each second sub-connector is electrically connected to multiple grid lines, the second sub-connector does not generate metallic stress, or the metallic stress generated by the second sub-connector is small and does not accumulate in the same direction as the metallic stress generated by the other second sub-connectors, thus avoiding inward stretching of the cell by metallic stress and preventing cell warping.

Description

Technical Field

[0001] This utility model relates to the field of solar photovoltaic technology, and in particular to a solar cell string and a battery module. Background Technology

[0002] During the production of solar cell modules, the metal stress generated by the welding ribbon after being heated and cooled during the welding process can cause the cell to stretch inward, which can easily lead to cell warping and seriously affect the yield and reliability of solar cell modules. Utility Model Content

[0003] In view of this, the present invention proposes a solar cell string and a battery module, which aims to at least partially solve the technical problem that the existing solder strip generates metal stress after being heated and cooled during the welding process, causing the battery cells to warp.

[0004] To achieve the above objectives, the technical solution of this utility model is implemented as follows:

[0005] In a first aspect, this utility model provides a solar cell string, which includes multiple solar cells and multiple conductive connectors, wherein two adjacent solar cells are connected through the multiple conductive connectors.

[0006] At least one side of the battery cell is provided with a plurality of grid lines;

[0007] The conductive connector includes at least one first sub-connector and a plurality of second sub-connectors. In the extending direction of the conductive connector, the plurality of second sub-connectors are spaced apart, and each second sub-connector is electrically connected to a plurality of the gate lines.

[0008] The first sub-connector is disposed between two adjacent second sub-connectors and is electrically connected to each of the two adjacent second sub-connectors.

[0009] In some possible implementations, the length of the second sub-connector ranges from 3mm to 10mm; and / or the spacing between two adjacent second sub-connectors ranges from 0.5mm to 2mm.

[0010] In some possible implementations, the second sub-connector has a plurality of protrusions on its surface facing the battery cell, the protrusions being electrically connected to the grid lines, and / or the protrusions being spaced apart from the grid lines.

[0011] In some possible implementations, the protrusion is at least one of a hemispherical structure, a columnar structure, or a frustum structure.

[0012] In some possible implementations, the height of the protrusion ranges from 20µm to 50µm.

[0013] In some possible implementations, the second sub-connector is a welding strip.

[0014] In some possible implementations, the first sub-connector is a first conductive printed piece, and the first sub-connector is disposed at the top of at least one of the gate lines.

[0015] In some possible implementations, the solar cell further includes an insulating element and a conductive element, the insulating element and the conductive element being respectively connected to the top end of the grid line; the grid line includes a first grid line and a second grid line, the first grid line and the second grid line are disposed on the back surface of the solar cell, the first grid line and the second grid line are alternately disposed along a first direction; the second sub-connector is directly connected to one of the first grid line and the second grid line through the conductive element and the first sub-connector; the first sub-connector and the second sub-connector are respectively insulated from the other of the first grid line and the second grid line through the insulating element.

[0016] In some possible implementations, the second sub-connector is a second conductive printed piece, which is electrically connected to a plurality of grid lines of the same electrical polarity on one of the solar cells.

[0017] In some possible implementations, the battery cell further includes an insulating member connected to the top end of the grid line; the grid line includes a first grid line and a second grid line; a first portion of the second sub-connector extends toward the battery cell and is connected to one of the first grid line and the second grid line; a second portion of the second sub-connector is insulated from the other of the first grid line and the second grid line via the insulating member.

[0018] In some possible implementations, the first sub-connector is a conductive sheet, a first end of which is connected to at least one of the grid lines on the edge of one of the battery cells, and a second end of which is connected to at least one of the grid lines on the edge of another adjacent battery cell; wherein the conductive sheet is connected to the top end of the grid line, or the conductive sheet is connected to the grid line through the insulating member, or the conductive sheet is connected to the grid line through a conductive member.

[0019] Secondly, this utility model embodiment also provides a battery assembly, which includes a plurality of solar cell strings as described above.

[0020] Compared with prior art, the present invention has the following advantages:

[0021] In this embodiment of the solar cell string, the conductive connector has a segmented structure. Multiple second sub-connectors are spaced apart along the direction of the conductive connector. A first sub-connector is provided between two adjacent second sub-connectors, and the two adjacent second sub-connectors are connected through the first sub-connector to ensure the continuity of current transmission and not affect the electrical performance of the battery module. In this way, each conductive connector is formed as a component that can transmit current, equivalent to a whole welding strip.

[0022] Each conductive connector includes multiple second sub-connectors. When each second sub-connector is electrically connected to multiple grid lines, the second sub-connector does not generate metallic stress, or the metallic stress generated by the second sub-connector is small and does not accumulate in the same direction with the metallic stress generated by the other second sub-connectors. In this way, the metallic stress can be prevented from causing the solar cell to be stretched inward, thus avoiding solar cell warping. When multiple solar cell strings form a solar module, the absence of solar cell warping can also improve the yield and reliability of the solar module.

[0023] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this utility model more obvious and understandable, specific embodiments of this utility model are given below. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0025] Figure 1 This is a schematic diagram of the structure of the battery assembly described in the embodiments of this application;

[0026] Figure 2 This is a partial structural diagram of the solar cell string according to the first embodiment of this application;

[0027] Figure 3 This is a partial structural diagram of the solar cell string according to the second embodiment of this application;

[0028] Figure 4 This is a partial structural diagram of the solar cell string according to the third embodiment of this application;

[0029] Figure 5 This is a partial structural diagram of the solar cell string according to the fourth embodiment of this application;

[0030] Figure 6 This is a partial structural diagram of the solar cell string according to the fifth embodiment of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] 10. Solar cell; 11. Grid line; 111. First grid line; 112. Second grid line; 13. Insulator; 14. Conductor;

[0033] 20. Conductive connector; 21. First sub-connector; 22. Second sub-connector;

[0034] X - First direction; Y - Second direction; Z - Third direction. Detailed Implementation

[0035] Exemplary embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0036] In the production of solar cell modules, electrical connections between cells are typically achieved using a single solder strip. During welding, the solder strip expands due to heat and contracts upon cooling, generating metallic stress. This stress accumulates in the same direction, causing the cells to stretch inwards and warp. Cell warping not only affects the module's appearance but also leads to quality issues such as microcracks and delamination, reducing power output and long-term reliability, severely impacting yield and reliability. This is particularly problematic for back-contact cells, where the light-receiving surface is unobstructed by any grid lines, with all grid lines located on the back side. While this design improves module conversion efficiency, cell warping is a significant issue. Current technologies mitigate warping by adjusting welding temperature and changing solder strip materials; however, the problem persists.

[0037] Reference Figures 1 to 6 As shown, this application provides a solar cell string and a battery module that can prevent cell warping and improve the yield and reliability of the battery module.

[0038] The solar cell strings and battery modules provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0039] In some embodiments, refer to Figure 1 As shown, the solar cell string includes multiple solar cells 10 and multiple conductive connectors 20, with adjacent solar cells 10 connected by the multiple conductive connectors 20; at least one side of each solar cell 10 is provided with multiple grid lines 11; further refer to Figure 2As shown, the conductive connector 20 includes at least one first sub-connector 21 and a plurality of second sub-connectors 22. In the extending direction of the conductive connector 20, the plurality of second sub-connectors 22 are spaced apart, and each second sub-connector 22 is electrically connected to a plurality of grid lines 11. The first sub-connector 21 is disposed between two adjacent second sub-connectors 22 and is electrically connected to the two adjacent second sub-connectors 22 respectively.

[0040] The solar cell string is composed of multiple solar cells 10 connected in series by conductive connectors 20. The solar cell string achieves the effective energy output of the photovoltaic power generation system by increasing the voltage.

[0041] In battery cell 10, refer to Figure 1 As shown, multiple grid lines 11 are spaced apart along a first direction X; multiple conductive connectors 20 are spaced apart along a second direction Y, and each conductive connector 20 is electrically connected to multiple grid lines 11 with the same electrical properties. It is understood that the first direction X and the second direction Y can be configured according to usage requirements. For example, the first direction X and the second direction Y may intersect; for example, the first direction X may be the width direction of the battery cell 10, and the second direction Y may be the length direction of the battery cell 10; or, for example, the first direction X and the second direction Y may be perpendicular. In the case where the first direction X and the second direction Y are perpendicular, the grid lines 11 extend along the second direction Y, the conductive connectors 20 extend along the first direction X, and multiple second sub-connectors 22 are spaced apart along the first direction X.

[0042] The solar cell 10 includes a light-receiving surface and a back-lighting surface. When multiple grid lines 11 are provided on both the light-receiving and back-lighting surfaces of the solar cell 10, the solar cell 10 is a bifacial solar cell 10. In this case, the conductive connector 20 connects the grid lines 11 (for example, positive grid lines 11) on the back-lighting surface of the preceding solar cell 10 to the grid lines 11 (for example, negative grid lines 11) on the light-receiving surface of the following solar cell 10, forming a continuous current path. When multiple grid lines 11 are provided only on the back-lighting surface of the solar cell 10, the solar cell 10 is a back-contact solar cell 10. In this case, the conductive connector 20 connects the positive grid lines 11 on the back-lighting surface of the preceding solar cell 10 to the positive grid lines 11 on the back-lighting surface of the following solar cell 10, and also connects the negative grid lines 11 on the back-lighting surface of the preceding solar cell 10 to the negative grid lines 11 on the back-lighting surface of the following solar cell 10, forming a continuous current path.

[0043] In this embodiment of the solar cell string, the conductive connector 20 has a segmented structure. Multiple second sub-connectors 22 are spaced apart along the setting direction of the conductive connector 20. A first sub-connector 21 is set between two adjacent second sub-connectors 22, and the two adjacent second sub-connectors 22 are connected through the first sub-connector 21 to ensure the continuity of current transmission and not affect the electrical performance of the battery module. In this way, each conductive connector 20 is formed as a component that can transmit current, equivalent to a whole welding strip.

[0044] Each conductive connector 20 includes multiple second sub-connectors 22. When each second sub-connector 22 is electrically connected to multiple grid lines 11, the second sub-connector 22 does not generate metallic stress, or the metallic stress generated by the second sub-connector 22 is small and does not accumulate in the same direction with the metallic stress generated by the other second sub-connectors 22. In this way, the metallic stress can be avoided from causing the solar cell 10 to be stretched inward, thus preventing the solar cell 10 from warping. When multiple solar cell strings form a solar module, the fact that the solar cell 10 does not warp can also improve the yield and reliability of the solar module.

[0045] In some possible implementations, the length of the second sub-connector 22 ranges from 3mm to 10mm. It is understood that the specific length of the second sub-connector 22 is set according to usage requirements to avoid the accumulation of metal stress in the same direction, which could cause warping of the battery cell 10. For example, the length of the second sub-connector 22 may be one of 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm.

[0046] In some possible implementations, the spacing between two adjacent second sub-connectors 22 can vary. It is understood that the specific spacing between two adjacent second sub-connectors 22 is set according to usage requirements, and it is necessary to avoid the accumulation of metal stress in the same direction, which could cause warping of the battery cell 10. For example, the spacing can be one of 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.7mm, or 2mm.

[0047] The length of the second sub-connector 22 and the spacing between two adjacent second sub-connectors 22 need to be adjusted according to the size of the battery cell 10 and the material properties of the second sub-connector 22, so as to avoid warping of the battery cell 10 and adapt to different battery cells 10 and battery modules.

[0048] In some possible implementations, the second sub-connector 22 has a plurality of protrusions on the surface of the battery cell 10 facing the protrusions, the protrusions being electrically connected to the grid lines 11, and / or the protrusions being spaced apart from the grid lines 11.

[0049] In this embodiment, the protrusion can serve as a stress buffer structure to prevent the second sub-connector 22 from bending and stretching the battery cell 10 in a direction away from the battery cell 10, so as to avoid warping of the battery cell 10.

[0050] In this embodiment, during the connection process between the second sub-connector 22 and the grid line 11 on the battery cell 10, the protrusion can be electrically connected to the grid line 11 or spaced apart from the grid line 11. This embodiment does not limit the positional relationship between the protrusion and the grid line 11.

[0051] In some possible implementations, the shape of the protrusion can also be set according to the usage requirements. For example, the protrusion may be at least one of a hemispherical structure, a columnar structure, or a frustum structure.

[0052] In some possible implementations, the height of the protrusion ranges from 20µm to 50µm. In the embodiments of this application, when the height of the protrusion is within the above range, the protrusion is a micro-protrusion structure disposed on the surface of the second sub-connector 22. The micro-protrusion structure can reduce the impact on the connection between the second sub-connector 22 and the gate line 11 while achieving stress buffering. That is, the second sub-connector 22 can be connected to the gate line 11 in a conventional manner, and the protrusion can be connected to the gate line 11 or spaced apart from the gate line 11.

[0053] It is understood that the embodiments of this application do not specifically limit the height of the protrusion, as long as it meets the usage requirements. For example, the height of the protrusion is one of 20um, 25um, 30um, 35um, 40um, 45um, and 50um.

[0054] In some possible implementations, the second sub-connector 22 is a welding strip.

[0055] In this embodiment, the solder strips and grid lines 11 are welded together. The welding is performed at a relatively high temperature, so the solder strips are heated during the connection process. Each conductive connector 20 includes multiple solder strips, which are shorter than the entire solder strip connecting two adjacent battery cells 10. During the electrical connection of each solder strip with multiple grid lines 11, each solder strip is independently heated and cooled, resulting in relatively small metal stress, especially compared to the metal stress generated after heating and cooling during the electrical connection of the entire solder strip with multiple grid lines 11. This effectively avoids warping of the battery cells 10 and improves the yield and reliability of the battery module.

[0056] Understandably, the material of the solder strip can be selected according to the application requirements. For example, the solder strip adopts a composite structure of copper core-tin plating-surface nano-coating, in which the nano-coating can be graphene or carbon nanotube materials to improve the thermal conductivity, electrical conductivity and mechanical strength of the solder strip.

[0057] In this embodiment of the application, the solder ribbon can connect multiple grid lines 11 on one battery cell 10, or it can connect multiple grid lines 11 on two battery cells 10.

[0058] In some possible implementations, the first sub-connector 21 is a first conductive printed piece, and the first sub-connector 21 is disposed within the battery cell 10. In the embodiments of this application, the first conductive printed piece is used to electrically connect two adjacent second sub-connectors 22, which has the advantage of simple structure; moreover, the first conductive printed piece on the battery cell 10 is current technology, that is, the first conductive printed piece in the embodiments of this application can be set using current technology.

[0059] In some possible implementations, the first sub-connector 21 is disposed at the top of at least one gate line 11.

[0060] In this embodiment, the second sub-connector 22 is connected to the top of the gate line 11, and the first sub-connector 21 is also disposed at the top of at least one gate line 11. In this way, the height difference between the second sub-connector 22 and the first sub-connector 21 can be avoided, as well as the connection problems caused by the height difference.

[0061] In some possible embodiments, the battery cell 10 further includes an insulating element 13 and a conductive element 14, which are respectively connected to the top end of the grid line 11; the grid line 11 includes a first grid line 111 and a second grid line 112, and the first grid line 111 and the second grid line 112 are disposed on the back surface of the battery cell 10, and the first grid line 111 and the second grid line 112 are alternately disposed along a first direction; the first grid line 111 and the second grid line 112 are electrically opposite.

[0062] When the conductive connector 20 is electrically connected to the battery cell 10, each conductive connector 20 needs to be electrically connected to a plurality of grid lines 11 with the same electrical properties. Thus, the conductive connector 20 can be connected to one of the first grid line 111 and the second grid line 112 through the conductive member 14, and the conductive connector 20 is insulated from the other of the first grid line 111 and the second grid line 112 through the insulating member 13.

[0063] In this embodiment, the conductive connector 20 includes a first sub-connector 21 and a second sub-connector 22. The second sub-connector 22 is connected to one of the first gate line 111 and the second gate line 112 through the conductive member 14, and the first sub-connector 21 is directly connected to one of the first gate line 111 and the second gate line 112. The first sub-connector 21 and the second sub-connector 22 are respectively insulated from the other of the first gate line 111 and the second gate line 112 through the insulating member 13.

[0064] Reference Figure 2As shown, the first sub-connector 21 is disposed at the top of the three grid lines 11 and spans across the middle second grid line 112. An insulating member 13 is disposed between the first sub-connector 21 and the middle second grid line 112 to achieve insulation. It is electrically connected to the two first grid lines 111 on both sides through a conductive member 14.

[0065] Reference Figure 3 As shown, the first sub-connector 21 is disposed at the top of the four grid lines 11, and an insulating member 13 is disposed between it and the two first grid lines 111 to achieve insulation, and it is electrically connected to the two second grid lines 112 through a conductive member 14.

[0066] In some possible implementations, the connection of the solar cell string includes the following steps:

[0067] The current technology divides the entire welding strip into multiple welding strip segments, with each segment serving as a second sub-connector 22.

[0068] A first conductive printout is printed in the space between two adjacent second sub-connectors 22, and the first conductive printout serves as the first sub-connector 21. The first conductive printout is printed using a conductive material, which may be a silver-containing conductive paste, copper-based conductive adhesive, or other highly conductive composite material.

[0069] Each second sub-connector 22 is independently welded, thereby electrically connecting the second sub-connector 22 to multiple grid lines 11. In the actual welding process, pulse welding technology can be used to independently weld each second sub-connector 22, controlling the welding temperature within an appropriate range (e.g., 200℃-250℃) and the welding time for each second sub-connector 22 within an appropriate range (e.g., 0.3 seconds-0.8 seconds). This ensures a strong weld on the second sub-connectors 22 while reducing heat input. Furthermore, using pulse welding technology reduces the heat-affected zone and lowers the risk of thermal deformation of the second sub-connectors 22.

[0070] In this embodiment, the solar cell string employs a segmented solder strip and printed welding method. The conductive material is supplemented by a first conductive printed component. The segmented solder strip welding disperses stress, reducing stress concentration along the entire solder strip as in current technologies, thereby preventing stress warping of the solar cell 10. The production of the solar cell string is compatible with existing production lines, reducing modification costs and facilitating implementation.

[0071] The solar cell strings of this application embodiment can be adapted to various sizes of solar cells in practical applications.

[0072] In the first specific example, for a 156mm × 156mm back-contact solar cell, a 5mm long second sub-connector 22 is used, with a 1mm gap between adjacent second sub-connectors 22. A first sub-connector 21 is formed by filling the gap area with a conductive paste containing 85% silver, and the printing thickness of the first sub-connector 21 is controlled at 30μm. The second sub-connectors 22 are soldered to the grid lines 11 using pulse soldering parameters of 220℃ and 0.5 seconds. Testing showed that the warpage of this solar cell is 0.3mm or less.

[0073] In the second specific example, for a large-size 182mm × 182mm back-contact solar cell, an 8mm long second sub-connector 22 is used, with a 1.5mm gap between adjacent second sub-connectors 22. Copper-based conductive adhesive is used as the first sub-connector 21, and 1% carbon nanotubes are added to enhance the conductivity of the first sub-connector 21. The welding of the second sub-connector 22 to the grid line 11 uses pulse welding parameters of 235℃ and 0.6 seconds. Testing showed that the uniformity of thermal stress distribution of the second sub-connector 22 was improved by 40%, and the warping problem of the solar cell 10 was essentially eliminated.

[0074] In the third specific example, for a large-size 166mm × 166mm back-contact solar cell, a 7mm long second sub-connector 22 is used, with a 1.2mm interval between adjacent second sub-connectors 22. The second sub-connector 22 is a solder ribbon with a copper core (0.15mm thick), tin plating (5μm thick), and a graphene coating (200nm thick). A conductive paste containing 88% silver and 1.5% carbon nanotubes is used as the printing paste for the first sub-connector 21. The welding of the second sub-connector 22 to the grid line 11 uses pulse welding parameters of 230℃ and 0.55 seconds. Testing showed that the warpage of the solar cell 10 was <0.2mm, and the tensile strength of the second sub-connector 22 was >3N / mm, indicating good results in both warpage and tensile strength tests.

[0075] In some other possible implementations, the second sub-connector 22 is a second conductive printed piece, which is electrically connected to a plurality of grid lines 11 with the same electrical properties on a cell 10.

[0076] In this embodiment, the second sub-connector 22 is a second conductive printed part. The structure of the solder ribbon connecting multiple grid lines 11 in the solar cell string is completely eliminated. The connection of multiple grid lines 11 on the cell 10 is achieved by printing the second sub-connector 22. Thus, the influence of solder ribbon stress is completely eliminated, the cell 10 will not warp, and a good electrical connection can be guaranteed.

[0077] In some possible embodiments, the battery cell 10 further includes an insulator 13 connected to the top end of the grid line 11; the grid line 11 includes a first grid line 111 and a second grid line 112; a first portion of the second sub-connector 22 extends toward the battery cell 10 and is connected to one of the first grid line 111 and the second grid line 112; a second portion of the second sub-connector 22 is insulated from the other of the first grid line 111 and the second grid line 112 by the insulator 13.

[0078] Reference Figure 4 As shown, the second sub-connector 22 is electrically connected to a plurality of gate lines 11 with the same electrical properties. The first gate line 111 and the second gate line 112 have opposite electrical properties. Thus, the second sub-connector 22 is electrically connected to one of the first gate line 111 and the second gate line 112, and needs to be insulated from the other of the first gate line 111 and the second gate line 112.

[0079] In this embodiment, the first part of the second sub-connector 22 extends toward the battery cell 10 and is connected to one of the first grid line 111 and the second grid line 112. The second sub-connector 22 can be electrically connected to one of the first grid line 111 and the second grid line 112 without the need for the conductive member 14, which can reduce the steps of setting the conductive member 14 and reduce the height of the battery cell 10 in the third direction Z after it is connected to the second sub-connector 22.

[0080] An insulating member 13 is provided between the second sub-connector 22 and the other of the first grid line 111 and the second grid line 112. The insulating member 13 can achieve insulation between the second sub-connector 22 and the other of the first grid line 111 and the second grid line 112. Furthermore, the insulating member 13 can be provided using current technology to better adapt to the current production line.

[0081] In some possible implementations, the first sub-connector 21 is a conductive sheet, with a first end connected to at least one grid line 11 on the edge of one battery cell 10, and a second end connected to at least one grid line 11 on the edge of another adjacent battery cell 10. In this way, the conductive sheet can effectively connect to two battery cells 10 respectively, thus enabling current transfer between the battery cells.

[0082] The conductive sheet needs to be electrically connected to the second sub-connector 22 connected to it on the gate line 11 with the same electrical properties. Thus, there can be various connection structures between the conductive sheet and the gate line 11.

[0083] Reference Figure 4 As shown, the first sub-connector 21 is directly connected to the top end of the first grid line 111, and the second sub-connector 22 is also directly connected to the top end of the first grid line 111; an insulating member 13 is provided between the second sub-connector 22 and the second grid line 112.

[0084] Reference Figure 5 As shown, an insulating member 13 is provided between the first sub-connector 21 and the first grid line 111, and an insulating member 13 is also provided between the second sub-connector 22 and the first grid line 111; the second sub-connector 22 is directly connected to the top end of the second grid line 112.

[0085] Reference Figure 6 As shown, an insulating member 13 is provided between the first sub-connector 21 and the first gate line 111, a conductive member 14 is provided between the first sub-connector 21 and the second gate line 112, and an insulating member 13 is also provided between the second sub-connector 22 and the first gate line 111; the top end of the second sub-connector 22 is directly connected to the second gate line 112.

[0086] The number of grid lines 11 connecting the conductive sheet to the edge of each battery cell 10 is not specifically limited; for example, referring to... Figure 4 and Figure 5 As shown, the conductive sheet is connected to a grid line 11 on the edge of each battery cell 10. For example, see reference... Figure 6 As shown, the conductive sheet is connected to two grid lines 11 on the edge of each battery cell 10. Of course, the conductive sheet can also be connected to three, four, five, or other grid lines 11 on the edge of each battery cell 10, depending on the specific application requirements.

[0087] In some possible implementations, the first sub-connector 21 has elastic deformation capability to absorb stress from the battery cell 10, grid line 11, etc.

[0088] Understandably, the material of the conductive sheet can be selected according to the application requirements. For example, the conductive sheet is made of copper alloy plated with tin, or it is made of conductive polymer composite material. The conductive sheet has good elastic deformation ability and good conductivity.

[0089] In some possible implementations, the connection of the solar cell string includes the following steps:

[0090] A conductive pattern is printed on one side of the battery cell 10 as a second sub-connector 22. The conductive paste used for printing is a highly conductive, low-shrinkage nano-silver paste or copper paste, with an organic carrier added to improve printing performance. Printing methods can include high-precision screen printing or inkjet printing.

[0091] The use of low-temperature curing conductive paste, with the curing temperature controlled at, for example, 150℃-180℃, is far lower than the welding temperature in current technology. This significantly reduces the thermal stress generated in the solar cell 10, conductive patterns, etc., and protects the performance of the solar cell 10.

[0092] The conductive sheet is connected to the grid line 11 at the edge of the battery cell 10, and the conductive sheet is connected to the end of the conductive pattern.

[0093] The solar cell string of this embodiment does not use solder ribbon, completely eliminating the stress of the metal solder ribbon and thoroughly solving the warping problem of the solar cell 10. Furthermore, the printed second sub-connector 22 allows for more flexible design and optimized current harvesting. The conductive sheet connects two adjacent solar cells 10; the conductive sheet has a certain degree of elasticity, which can provide appropriate stress buffering and improve the reliability of the solar module.

[0094] In this embodiment, the conductive element 14 can be omitted, and the second sub-connector 22 is printed. The second sub-connector 22 can be made thinner, thus reducing the height of the second sub-connector 22 after it is connected to the solar cell 10, making it suitable for use in thinner solar cell strings.

[0095] The solar cell strings of this application embodiment have various uses in practical applications.

[0096] In the first specific example, for a conventional back-contact solar cell, the back surface uses 325-mesh screen-printed nano-silver paste lines with a silver content of 92%. After drying, the line width of the second sub-connector 22 is 0.8 mm and the thickness is 60 μm. The conductive sheet is made of phosphor bronze material with a 3 μm tin layer plated on the surface. Conductive adhesive is applied to the connection points and cured at 150°C for 30 minutes.

[0097] In the second specific example, for the high-efficiency (more efficient than conventional) back-contact solar cell, inkjet printing technology is used to form fine conductive patterns, reducing the linewidth of the second sub-connector 22 to 0.3 mm. The conductive sheet is replaced with a carbon nanotube-reinforced conductive composite material, exhibiting anisotropic conductivity. The curing process is optimized to 170°C for 20 minutes.

[0098] In the second specific example, for flexible back-contact solar cells (bendable and foldable cells), conductive ink on a polyimide substrate is used to form 0.25mm wide conductive lines via inkjet printing. The conductive sheets utilize shape memory alloy materials, allowing for adaptive tension adjustment within a 40-80°C range. Anisotropic conductive film (ACF) is used at the joints to achieve mechanical and electrical connections.

[0099] The solar cell string of this application embodiment, using segmented solder strips as the second sub-connector 22 and printed first sub-connector 21, and using conductive sheets as the first sub-connector 21 with printed second sub-connector 22, effectively solves the problem of cell warpage 10 in the manufacturing of back-contact solar cell modules. This not only improves product yield and reliability but also reduces production costs and enhances market competitiveness, demonstrating significant economic and social benefits. Moreover, the two structures described above can be combined to accommodate more solar cell strings.

[0100] In some embodiments, this application also provides a battery assembly comprising a plurality of solar cell strings as described above. Because the solar cells 10 in the solar cell strings are relatively flat and do not have warping issues, the battery assembly has the advantages of high yield and good reliability.

[0101] In some embodiments, this application also provides a photovoltaic power generation system, which includes the aforementioned plurality of battery modules.

[0102] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0103] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. For embodiments of devices, electronic devices, computer-readable storage media, and computer program products containing instructions, the descriptions are relatively simple because they are basically similar to the method embodiments; relevant parts can be referred to the descriptions of the method embodiments.

[0104] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model are included within the scope of protection of this utility model.

Claims

1. A solar cell string, characterized by, It includes multiple battery cells (10) and multiple conductive connectors (20), with two adjacent battery cells (10) connected by the multiple conductive connectors (20); At least one side of the battery cell (10) is provided with a plurality of grid lines (11); The conductive connector (20) includes at least one first sub-connector (21) and a plurality of second sub-connectors (22). In the extending direction of the conductive connector (20), the plurality of second sub-connectors (22) are spaced apart, and each second sub-connector (22) is electrically connected to a plurality of the gate lines (11). The first sub-connector (21) is disposed between two adjacent second sub-connectors (22) and is electrically connected to the two adjacent second sub-connectors (22) respectively.

2. The solar cell string according to claim 1, characterized in that, The length of the second sub-connector (22) ranges from 3mm to 10mm; and / or the spacing between two adjacent second sub-connectors (22) ranges from 0.5mm to 2mm.

3. The solar cell string according to claim 1, characterized in that, The second sub-connector (22) has a plurality of protrusions on the surface facing the battery cell (10), the protrusions being electrically connected to the grid line (11), and / or the protrusions being spaced apart from the grid line (11).

4. The solar cell string according to claim 3, characterized in that, The protrusion is at least one of a hemispherical structure, a columnar structure, or a frustum structure.

5. The solar cell string according to claim 3, characterized in that, The height of the protrusion ranges from 20um to 50um.

6. The solar cell string according to claim 1, characterized in that, The second sub-connector (22) is a welding strip.

7. The solar cell string according to claim 1, characterized in that, The first sub-connector (21) is a first conductive printed piece, and the first sub-connector (21) is disposed at the top of at least one of the gate lines (11).

8. The solar cell string according to any one of claims 1-7, characterized in that, The battery cell (10) also includes an insulating element (13) and a conductive element (14), the insulating element (13) and the conductive element (14) being connected to the top end of the grid line (11), respectively; The grid line (11) includes a first grid line (111) and a second grid line (112). The back surface of the battery cell (10) is provided with the first grid line (111) and the second grid line (112). The first grid line (111) and the second grid line (112) are alternately arranged along a first direction. The second sub-connector (22) is directly connected to one of the first gate line (111) and the second gate line (112) via the conductive member (14) and the first sub-connector (21); the first sub-connector (21) and the second sub-connector (22) are respectively insulated from the other of the first gate line (111) and the second gate line (112) via the insulating member (13).

9. The solar cell string according to claim 1, characterized in that, The second sub-connector (22) is a second conductive printed piece, and the second sub-connector (22) is electrically connected to a plurality of grid lines (11) with the same electrical properties on a single battery cell (10).

10. The solar cell string according to claim 8, characterized in that, The battery cell (10) also includes an insulating member (13), which is connected to the top end of the grid line (11); the grid line (11) includes a first grid line (111) and a second grid line (112); The first portion of the second sub-connector (22) extends toward the battery cell (10) and is connected to one of the first grid line (111) and the second grid line (112); the second portion of the second sub-connector (22) is insulated from the other of the first grid line (111) and the second grid line (112) by the insulator (13).

11. The solar cell string according to claim 10, characterized in that, The first sub-connector (21) is a conductive sheet, the first end of which is connected to at least one of the grid lines (11) on the edge of one of the battery cells (10), and the second end of which is connected to at least one of the grid lines (11) on the edge of another adjacent battery cell (10); wherein, The conductive sheet is connected to the top end of the gate line (11), or the conductive sheet is connected to the gate line (11) through the insulating member (13), or the conductive sheet is connected to the gate line (11) through the conductive member (14).

12. A battery assembly, characterized in that, It includes multiple solar cell strings as described in any one of claims 1-11.

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