Back contact laminated solar cell string and manufacturing method, laminated solar cell module

Abstract

The present application discloses a back-contact laminated solar cell string and a manufacturing method, and a laminated solar cell assembly, comprising a plurality of back-contact solar cells arranged in series and overlapping in sequence, wherein the positive and negative electrodes of the back-contact solar cells are both arranged on the back of the back-contact solar cells, a plurality of through holes are arranged on one side edge of the back-contact solar cells, two adjacent back-contact solar cells have an overlapping area, the through holes of the lower back-contact solar cell are located in the overlapping area, and the two adjacent back-contact solar cells are connected in series through a conductive wire, and the conductive wire passes through the through holes, so as to realize the stacking arrangement of the plurality of back-contact solar cells.

Description

Technical Field

[0001] The present invention generally relates to the photovoltaic field, specifically to the field of back-contact solar cell modules, and in particular to a back-contact laminated solar cell string and a manufacturing method, and a laminated solar cell module. Background Art

[0002] The stacked module (also known as the shingled module) technology is a new module design scheme that stacks and arranges the cells, connects them into battery strings through conductive glue, solder paste and other materials, and then laminates them into modules after series-parallel layout. By improving the interconnection structure design of the cells, more cells can be arranged in a limited area, improving the utilization of the space area and the power generation of the module.

[0003] At present, back-contact solar cells (such as IBC, MWT, and EWT solar cells) have received widespread attention. Since there is no main grid line on the front side, or even any electrode pattern, the positive and negative electrodes are located on the back side of the cell, which reduces the shading of the cell, thereby effectively increasing the short-circuit current of the cell and improving the energy conversion efficiency of the cell.

[0004] The electrodes of existing back-contact solar cells are all arranged on the back of the cells, and it is impossible to directly stack the cells and connect the positive and negative electrodes of adjacent cells through conductive glue to form a cell string like traditional crystalline silicon solar cells. Summary of the invention

[0005] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a back-contact laminated solar cell string and a manufacturing method, and a laminated solar cell module that realize a laminated arrangement of back-contact solar cells.

[0006] In a first aspect, the back-contact stacked solar cell string of the present invention comprises a plurality of back-contact solar cells arranged in sequence and overlapped with each other and connected in series, wherein the positive and negative electrodes of the back-contact solar cell cells are both arranged on the back side of the back-contact solar cell cells, a plurality of through holes are arranged on one side edge of the back-contact solar cell cells, an overlapping area exists between two adjacent back-contact solar cell cells, the through holes of the lower back-contact solar cell cell are located in the overlapping area, and the two adjacent back-contact solar cell cells are connected in series via a conductive wire, and the conductive wire passes through the through holes.

[0007] In a second aspect, a back-contact stacked solar cell module of the present invention includes a plurality of electrically connected back-contact stacked solar cell strings.

[0008] In a third aspect, a method for manufacturing a back-contact laminated solar cell string of the present invention comprises the following steps:

[0009] A plurality of through holes are formed on one side edge of the back contact solar cell sheet, wherein the through holes penetrate the back contact solar cell sheet along the thickness direction of the back contact solar cell sheet;

[0010] Arrange a plurality of the back-contact solar cell sheets in an overlapping manner in sequence, so that two adjacent back-contact solar cell sheets have an overlapping area, and the through hole of the back-contact solar cell sheet located at the bottom is located in the overlapping area;

[0011] A conductive wire is passed through the through hole, and two ends of the conductive wire are respectively connected to electrodes of different polarities of two adjacent back-contact solar cells to obtain a back-contact stacked solar cell string.

[0012] According to the technical solution provided in the embodiment of the present application, by setting a plurality of through holes on one side edge of the back-contact solar cell sheet, there is an overlapping area between two adjacent back-contact solar cell sheets, and the two adjacent back-contact solar cell sheets are connected in series through a conductive wire, and the conductive wire passes through the through holes, thereby realizing a stacking arrangement of multiple back-contact solar cell sheets, which can solve the problem that it is difficult to achieve stacking arrangement of existing back-contact solar cell sheets. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0014] Figure 1 A schematic diagram of the structure of a back-contact laminated solar cell string according to an embodiment of the present invention;

[0015] Figure 2 A schematic structural diagram of a back-contact solar cell sheet of a back-contact stacked solar cell string according to an embodiment of the present invention that is a busbar-free back-contact solar cell sheet;

[0016] Figure 3 A schematic structural diagram of a back-contact solar cell sheet of a back-contact stacked solar cell string according to an embodiment of the present invention, which is a main-grid back-contact solar cell sheet;

[0017] Figure 4 A schematic diagram of the structure of the conductive wires, through holes and insulating medium of a back-contact laminated solar cell string according to an embodiment of the present invention;

[0018] Figure 5 It is a schematic structural diagram of a back-contact solar cell sheet of a back-contact stacked solar cell string according to an embodiment of the present invention that is not assembled by rotation;

[0019] Figure 6 It is a schematic structural diagram of the back-contact solar cell sheet of the back-contact stacked solar cell string of an embodiment of the present invention being rotated 180 degrees for assembly;

[0020] Figure 7 A schematic diagram of the structure of a back-contact solar cell sheet in a back-contact stacked solar cell module according to an embodiment of the present invention, wherein the back-contact solar cell sheet is a regular hexagonal back-contact solar cell sheet divided into two equal parts;

[0021] Figure 8 This is a schematic structural diagram of a back-contact solar cell sheet in a back-contact stacked solar cell module according to an embodiment of the present invention, in which a regular hexagonal back-contact solar cell sheet is divided into four equal parts. DETAILED DESCRIPTION

[0022] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0023] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0024] One embodiment of the present invention is, please refer to Figure 1-3 The back-contact stacked solar cell string of the present invention comprises a plurality of back-contact solar cell sheets 10 which are arranged in sequence and overlap each other and are connected in series. The positive and negative electrodes of the back-contact solar cell sheets 10 are both arranged on the back side of the back-contact solar cell sheets. A plurality of through holes 13 are arranged on one side edge of the back-contact solar cell sheets 10. There is an overlapping area between two adjacent back-contact solar cell sheets 10. The through holes 13 of the lower back-contact solar cell sheet are located in the overlapping area. The two adjacent back-contact solar cell sheets 10 are connected in series through a conductive wire 14, and the conductive wire 14 passes through the through holes 13.

[0025] In the embodiment of the present invention, the positive and negative electrodes of the back-contact solar cell are both arranged on the back side of the back-contact solar cell, and the light-receiving surface of the cell has no electrode to block the light, thereby improving the power of the back-contact stacked solar cell string.

[0026] Two adjacent back-contact solar cells are connected in series through a conductive wire. Specifically, when stacking back-contact solar cells, one end of the conductive wire can be electrically connected to the positive electrode of one back-contact solar cell, and the other end of the conductive wire can be electrically connected to the negative electrode of another back-contact solar cell; one end of the conductive wire can also be electrically connected to the negative electrode of one back-contact solar cell, and the other end of the conductive wire can be electrically connected to the positive electrode of another back-contact solar cell, so as to connect two adjacent back-contact solar cells in series. Back-contact stacked solar cell strings reduce series resistance and resistance loss, and significantly improve the power of stacked components.

[0027] Arrange multiple back-contact solar cells in sequence, and there are overlapping areas between adjacent back-contact solar cells, that is, arrange multiple back-contact solar cells in sequence and overlap, without gaps between back-contact solar cells, fully utilize the available area of ​​the string surface, and improve the conversion efficiency and output efficiency of the string. There is no electrode on the light-receiving surface of the back-contact solar cell to block the light, which can improve the efficiency of the module.

[0028] The conductive wire passes through the through hole at one side edge of the back-contact solar cell sheet. When stacking the solar cells, the through hole of the lower back-contact solar cell sheet is located in the overlapping area of ​​the two back-contact solar cells, which can reduce the shielding of the light-receiving surface of the back-contact solar cell sheet by the overlapping area, making the structure of the back-contact stacked solar cell string more reasonable. The conductive wire passes through the through hole, which can limit the conductive wire and facilitate fixing the relative position between the conductive wire and the back-contact solar cell sheet; at the same time, it can also facilitate stacking the back-contact solar cell sheets and reduce the thickness of the overlapping area; at the same time, it can also reduce the length of the conductive wire, reduce the power loss on the conductive wire, avoid excessive bending of the conductive wire, and improve the reliability of the conductive wire connection.

[0029] A plurality of back-contact solar cells connected in series form a stacked cell string. The back-contact stacked solar cell module can be one or more rows of stacked cell strings. The cells in each row of stacked cell strings are connected in series, and stacked cell strings in different rows are connected in parallel or in series.

[0030] When connecting back-contact solar cells, since the positive and negative electrodes on the back of the back-contact solar cells are arranged in an alternating manner, when connecting two adjacent back-contact solar cells in series through conductive wires, refer to Figure 6 , one of the back-contact solar cells can be rotated 180° so that the positive electrode of one back-contact solar cell is directly opposite to the negative electrode of the other back-contact solar cell, that is, the positive electrode of one back-contact solar cell and the negative electrode of the other back-contact solar cell are in the same plane perpendicular to the back of the back-contact solar cell. The conductive wire does not need to be bent on the back of the back-contact solar cell, and the distance of current transmission can be reduced, reducing the loss of the back-contact stacked solar cell string and improving the efficiency of the component.

[0031] refer to Figure 5 Of course, the back-contact solar cell panel does not need to be rotated 180°. The positive electrode of one back-contact solar cell panel and the negative electrode of another back-contact solar cell panel will be misaligned, and the conductive wire needs to be bent on the back of the back-contact solar cell panel to achieve series connection of two adjacent back-contact solar cells.

[0032] Further, the conductive wire 14 includes a first sub-conductive wire and a second sub-conductive wire, and the first sub-conductive wire is electrically connected to the second sub-conductive wire;

[0033] In two adjacent back-contact solar cells 10, the positive electrode of the lower back-contact solar cell 10 is electrically connected to the first sub-conductive line, and the negative electrode of the upper back-contact solar cell 10 is electrically connected to the second sub-conductive line; or,

[0034] The negative electrode of the back-contact solar cell 10 located at the bottom is electrically connected to the first sub-conductive line, and the positive electrode of the back-contact solar cell 10 located at the top is electrically connected to the second sub-conductive line.

[0035] In the embodiment of the present invention, a detailed description is given by taking the example that the first sub-conductive wire is electrically connected to the positive electrode of the back-contact solar cell sheet, and the second sub-conductive wire is electrically connected to the negative electrode of the back-contact solar cell sheet. The back-contact solar cell sheet may be a main-grid cell sheet, and the main-grid cell sheet may also be a case where there is only a positive main grid, a negative fine grid line, or a positive fine grid line and a negative main grid. The first sub-conductive wire may be electrically connected to the positive main grid or the positive fine grid line, and the second sub-conductive wire may be electrically connected to the negative main grid or the negative fine grid line. Figure 3 The schematic diagram of a back-contact solar cell sheet including a positive main grid and a negative main grid. The through hole can be set at the end of the first sub-conductive wire, the end of the main grid, or the bending junction of the first sub-conductive wire and the second sub-conductive wire. When the first sub-conductive wire and the second sub-conductive wire are connected to the fine grid wire of the back-contact solar cell sheet, the width of the back-contact solar cell sheet main grid can be reduced, and the distance of current transmission can be reduced, the loss of the back-contact laminated solar cell string can be reduced, and the efficiency of the component can be improved.

[0036] Back contact solar cells can also be busbar-free cells. Figure 2 The schematic diagram of a back-contact solar cell sheet includes a positive electrode fine grid line and a negative electrode fine grid line. The first sub-conductive wire is electrically connected to the positive electrode fine grid line, and the second sub-conductive wire is electrically connected to the negative electrode fine grid line. The first sub-conductive wire and the second sub-conductive wire can replace the main grid, saving the electrode slurry required for manufacturing the back-contact solar cell sheet electrode, and reducing the production cost of the back-contact solar cell sheet. Of course, the first sub-conductive wire and the second sub-conductive wire can also be replaced by using one conductive wire, and of course, they can also be replaced by using three or more sub-conductive wires.

[0037] Furthermore, one end of the first sub-conductive wire passes through the through hole 13 to be electrically connected to the second sub-conductive wire, which can reduce the difficulty of processing the back-contact laminated solar cell string.

[0038] Furthermore, the portion of the conductive wire 14 located in the overlapping area is a flat conductive wire. The flat conductive wire can be, but is not limited to, an elliptical conductive wire, a rectangular conductive wire, and an approximately rectangular conductive wire. The flat conductive wire is easier to form a good contact during electrical connection, which is convenient for electrical connection. Of course, the length direction of the flat conductive wire is parallel to the back-contact solar cell sheet, which can reduce the gap between two adjacent back-contact solar cell sheets, and can reduce the thickness of the back-contact laminated solar cell string. At the same time, the area of ​​the conductive wire facing the back-contact solar cell sheet is increased. When laminating the back-contact solar cell sheet, the pressure between the conductive wire and the back-contact solar cell sheet can be reduced, thereby reducing the breakage rate.

[0039] Furthermore, the through hole 13 is a through slot, which facilitates the conductive wire to pass through the through hole, reduces the processing difficulty of the back contact laminated solar cell string, and improves the processing speed of the back contact laminated solar cell string. The through slot is processed at the edge of the back contact solar cell sheet. Specifically, the through hole intersects with the edge of the back contact solar cell sheet to form the through slot.

[0040] Furthermore, an insulating medium 15 is filled between the hole wall of the through hole 13 and the conductive wire 14. The insulating medium can isolate the through hole 13 from the conductive wire and play a buffering role during the lamination process of the back-contact solar cell sheet, thereby reducing the stress between the conductive wire and the through hole and reducing the breakage rate. The insulating medium can also fix the conductive wire and the through hole and improve the connection strength between the conductive wire and the back-contact solar cell sheet.

[0041] Preferably, the insulating medium is insulating ink, insulating wax, epoxy resin, polyurethane resin, acrylic resin, silicone resin or solder resist ink.

[0042] Furthermore, an insulating adhesive layer 20 is provided between two adjacent back-contact solar cells 10, the insulating adhesive layer 20 is located in the overlapping area, and the conductive wire 14 passes through the insulating adhesive layer 20. The insulating adhesive layer can be provided between the conductive wires by screen printing or automatic dispensing, and the insulating adhesive layer is distributed in strips or lattices. The insulating adhesive layer can play a buffering role when laminating the back-contact laminated solar cell string, reduce the stress between the two adjacent back-contact solar cells in the overlapping area, and reduce the risk of back-contact solar cell fragments and hidden cracks. At the same time, the insulating adhesive layer can play a role in connecting the two adjacent back-contact solar cells, improve the connection strength between the back-contact solar cells, and improve the reliability of the back-contact laminated solar cell string. At the same time, the insulating adhesive layer can prevent the back-contact solar cell from short-circuiting, improve the stability and reliability of the back-contact laminated solar cell string, and ensure the power generation efficiency of the back-contact laminated solar cell module. The insulating adhesive layer is insulating ink, insulating wax, epoxy resin, polyurethane resin, acrylic resin, silicone resin or solder resist ink.

[0043] Furthermore, at least part of the surface of the conductive wire 14 is provided with a hot-melt conductive layer, and the material of the hot-melt conductive layer can be a metal or alloy with a melting point between 70-180 degrees. Specifically, the material of the hot-melt conductive layer includes a single substance or alloy of any one of Ag, Bi, Cd, Ga, In, Pb, Sn, Ti, and Zn; the material of the hot-melt conductive layer can also be a conductive resin with a softening temperature between 90-120 degrees. Further, the conductive resin includes a resin substrate and conductive particles arranged in the resin substrate, the resin substrate includes any one of cellulose acetate, fluororesin, polysulfone resin, polyester resin, polyamide resin, polyurethane resin and polyolefin resin, and the conductive particles include at least any one of gold, silver, copper, aluminum, zinc, nickel and graphite. The shape of the conductive particles can be granular and / or flaky. The thickness of the hot-melt conductive layer is between 1 micron and 10 microns. The hot-melt conductive layer acts as a solder or adhesive after melting and softening. The thickness thereof is within the above range, which can ensure that there is a sufficient amount of solder or adhesive after the hot-melt conductive layer softens and melts, but not too much to affect the conductive performance.

[0044] Furthermore, the conductive wire 14 is at least partially embedded in a thermoplastic polymer film, and the thermoplastic polymer film is one or a combination of polyvinyl butyral, polyolefin or ethylene-vinyl acetate copolymer. The thermoplastic polymer film is a commonly used component packaging material. The conductive wire is embedded in the thermoplastic polymer film to facilitate the connection between the conductive wire and the back electrode of the battery. The conductive wire is fixedly connected to the battery electrode through a hot pressing process, and finally a battery component is formed through lamination.

[0045] The thermoplastic polymer film can also be a composite structure of a base layer and an adhesive layer. That is, it includes a base layer and an adhesive layer arranged on the base layer, the conductive wire is fixed to the adhesive layer, and the top of the conductive wire protrudes from the adhesive layer so as to be connected to the electrode. The conductive wire is embedded in the thermoplastic polymer film to ensure the reliability of the connection between the conductive wire and the electrode. The material of the base layer can include at least any one of cellulose acetate, fluororesin, polysulfone resin, polyester resin, polyamide resin, polyurethane resin and polyolefin resin. The material of the adhesive layer can be selected from at least any one of acrylic resin, rubber resin, silicone resin, epoxy resin, polyvinyl ether, polyvinyl butyral, ethylene-vinyl acetate, polymethyl methacrylate, methyl methacrylate copolymer, methacrylic acid copolymer and acrylic acid copolymer. The thickness of the thermoplastic polymer film can be between 5 microns and 150 microns to ensure that the thermoplastic polymer film has sufficient stability under hot pressing, and the surface shrinkage of the polymer film is small after cooling, and the surface is flat.

[0046] refer to Figure 6Furthermore, two adjacent back-contact solar cell sheets 10 are placed in reverse order so that the positive electrode of any one of the two adjacent back-contact solar cell sheets 10 is in line with the negative electrode of the other back-contact solar cell sheet 10. This allows the positive and negative electrodes of the two adjacent back-contact solar cell sheets to face each other, reduces the bending of the conductive wire, and facilitates the electrical connection of the two adjacent back-contact solar cell sheets.

[0047] Furthermore, the width of the overlapping area is 0.1-3mm, which can ensure the stability of the connection between adjacent back-contact solar cells 10 through the through-electrode 11, and at the same time, avoid the loss caused by the through-electrode 11 excessively blocking the light-emitting surface of the solar cell, reduce the resistance loss, and improve the power of the back-contact stacked solar cell module. If the width of the overlapping area of ​​adjacent back-contact solar cells is less than 0.1mm, the through-hole processing is difficult, and the area of ​​the common electrode is small, which affects the transmission of current and the reliability of contact; if the width of the overlapping area of ​​adjacent back-contact solar cells 10 is greater than 3mm, due to the large area of ​​the overlapping area, the photovoltaic conversion efficiency of solar energy cannot be significantly improved, and the larger the area of ​​the overlapping area, the more ineffective area of ​​the cell. The width of the overlapping area of ​​adjacent cells can be, but not limited to, 0.5-2mm.

[0048] Furthermore, the back-contact solar cell is a whole cell or a sub-solar cell obtained by cutting the whole cell into equal parts. When the back-contact solar cell is a sub-solar cell obtained by cutting the whole cell into equal parts, it can be, but not limited to, a half solar cell, a third solar cell, a quarter solar cell, a fifth solar cell or a sixth solar cell formed by cutting the whole cell in a direction parallel to its fine grid lines. Cutting the whole cell to form multiple sub-solar cells can reduce the resistance of a single back-contact solar cell and the current of each battery string, thereby reducing the influence of electrode resistance loss and improving the output power of the battery module.

[0049] Another embodiment of the present invention is a back-contact stacked solar cell module, comprising a plurality of electrically connected back-contact stacked solar cell strings.

[0050] In the embodiment of the present invention, the back-contact solar cell stacking arrangement in the cell string has a simple structure and high reliability, and can reduce the series resistance and resistance loss, and improve the power of the component.

[0051] refer to Figure 7 and 8Furthermore, the component is square, and the square area 30 is filled with a plurality of back-contact solar cells 10, and the back-contact solar cells 10 are obtained by equally dividing a regular hexagonal back-contact solar cell.

[0052] In the embodiment of the present invention, the solar cell sheet is obtained by equally dividing the regular hexagonal back-contact solar cell sheet, and the light-receiving area of ​​each solar cell sheet is equal. The solar cell sheets can be directly connected in series, which simplifies the connection circuit, ensures that the current corresponding to the maximum power point of each solar cell group is the same, can avoid the bucket effect of the solar cell sheets connected in series, and improve the power generation efficiency of the solar cell module. At the same time, it can avoid the utilization rate of silicon rod raw materials, reduce the waste of raw materials, and reduce production costs compared to the traditional quadrilateral or nearly square solar cell sheet. At the same time, the frame is filled with solar cells. Compared with the traditional quadrilateral or nearly square solar cell sheet, there is no need to set chamfers at the corners, which avoids the waste of blank areas located in the chamfered area when the traditional chamfered nearly square cell sheet is laid, and can improve the light-receiving area, module power and power generation efficiency of the solar cell module.

[0053] like Figure 7 As shown, the solar cell sheet can be obtained by dividing the regular hexagonal back-contact solar cell sheet into two equal parts; Figure 8 As shown, the solar cell sheet can also be obtained by dividing the regular hexagonal back-contact solar cell sheet into four equal parts. It is only necessary to satisfy that the solar cell sheet fills the frame. The gap between the solar cell sheet and the frame is reduced, and the light receiving area of ​​the solar cell module is increased.

[0054] Of course, it is understandable that the battery cells of the assembly of the present invention may also be battery cells of conventional shapes and are not limited to special-shaped battery cells.

[0055] Another embodiment of the present invention is a method for manufacturing a back-contact laminated solar cell string, comprising the following steps:

[0056] A plurality of through holes 13 are formed on one side edge of the back contact solar cell sheet 10 , and the through holes 13 penetrate the back contact solar cell sheet 10 along the thickness direction of the back contact solar cell sheet 10 ;

[0057] Multiple back-contact solar cell sheets 10 are arranged in an overlapping manner in sequence, so that two adjacent back-contact solar cell sheets 10 have an overlapping area, and the through hole 13 of the lower back-contact solar cell sheet 2 is located in the overlapping area;

[0058] The conductive wire 14 is passed through the through hole 13, and the two ends of the conductive wire 14 are respectively connected to electrodes of different polarities of two adjacent back-contact solar cells 10 to obtain a back-contact stacked solar cell string.

[0059] In an embodiment of the present invention, a plurality of through holes are formed on one side edge of a back-contact solar cell sheet, a plurality of back-contact solar cells are arranged in an overlapping manner, a conductive wire is passed through the through holes, and both ends of the conductive wire are respectively connected to the positive and negative electrodes of two adjacent back-contact solar cells, so that two adjacent back-contact solar cells are connected in series, thereby reducing the series resistance and resistance loss, and significantly improving the power of the stacked assembly.

[0060] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A back contact laminated solar cell string, characterized in that: It comprises a plurality of back-contact solar cells arranged in sequence and overlapped and connected in series, wherein the positive electrode and the negative electrode of the back-contact solar cell are both arranged on the back side of the back-contact solar cell, a plurality of through holes are arranged on one side edge of the back-contact solar cell, two adjacent back-contact solar cells have an overlapping area, the through holes of the lower back-contact solar cell are located in the overlapping area, and the two adjacent back-contact solar cells are connected in series through a conductive wire, and the conductive wire passes through the through holes; Wherein, the conductive wire comprises a first sub-conductive wire and a second sub-conductive wire, and the first sub-conductive wire is electrically connected to the second sub-conductive wire; the back contact solar cell sheet comprises a main grid, and the through hole is arranged at an end of the main grid; In two adjacent back-contact solar cells, the positive electrode of the lower back-contact solar cell is electrically connected to the first sub-conductive line, and the negative electrode of the upper back-contact solar cell is electrically connected to the second sub-conductive line; or, The negative electrode of the back-contact solar cell sheet located at the bottom is electrically connected to the first sub-conductive line, and the positive electrode of the back-contact solar cell sheet located at the top is electrically connected to the second sub-conductive line.

2. The back contact laminated solar cell string according to claim 1, characterized in that: One end of the first sub-conductive line passes through the through hole and is electrically connected to the second sub-conductive line.

3. The back contact laminated solar cell string according to claim 1, characterized in that: The portion of the conductive wire located in the overlapping area is a flat conductive wire.

4. The back contact laminated solar cell string according to claim 1, characterized in that: The through hole is a through hole.

5. The back contact laminated solar cell string according to claim 1, characterized in that: An insulating medium is filled between the hole wall of the through hole and the conductive wire.

6. The back contact laminated solar cell string according to claim 1, characterized in that: An insulating adhesive layer is arranged between two adjacent back-contact solar cell sheets, and the insulating adhesive layer is located in the overlapping area; the conductive wire passes through the insulating adhesive layer.

7. The back-contact laminated solar cell string according to claim 1, characterized in that: At least a portion of the surface of the conductive wire is provided with a hot-melt conductive layer.

8. The back contact laminated solar cell string according to claim 1, characterized in that: The conductive lines are at least partially embedded in the thermoplastic polymer film.

9. A back-contact laminated solar cell module, characterized in that: A back-contact laminated solar cell string comprising a plurality of electrically connected back-contact laminated solar cell strings as claimed in any one of claims 1 to 8.

10. The back contact laminated solar cell module according to claim 9, characterized in that: The module is in a square shape, and the square area is filled with a plurality of back-contact solar cells, which are obtained by equally dividing a regular hexagonal back-contact solar cell.

11. A method for manufacturing a back-contact laminated solar cell string, characterized in that: The manufacturing method is used to obtain the back-contact laminated solar cell string according to any one of claims 1 to 8, and the manufacturing method comprises the following steps: A plurality of through holes are formed on one side edge of the back contact solar cell sheet, wherein the through holes penetrate the back contact solar cell sheet along the thickness direction of the back contact solar cell sheet; Arrange a plurality of the back-contact solar cell sheets in an overlapping manner in sequence, so that two adjacent back-contact solar cell sheets have an overlapping area, and the through hole of the back-contact solar cell sheet located at the bottom is located in the overlapping area; A conductive wire is passed through the through hole, and two ends of the conductive wire are respectively connected to electrodes of different polarities of two adjacent back-contact solar cells to obtain a back-contact stacked solar cell string.

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