Flexible interconnection structure of battery string, preparation method of flexible interconnection structure and photovoltaic module

Abstract

The invention discloses a flexible interconnection structure of a battery string, a preparation method thereof and a photovoltaic module, the flexible interconnection structure comprises a plurality of battery pieces which are electrically connected through a metal interconnection belt, and each battery piece comprises a first light receiving surface and a second light receiving surface; the metal electrode of the first light-receiving surface and the metal electrode of the second light-receiving surface correspondingly form a flexible electrical connection structure with the first metal interconnection band and the second metal interconnection band through strip-shaped flexible transparent glue. According to the invention, the reliability of the flexible photovoltaic module is obviously improved, the process of large-scale popularization and application of the flexible photovoltaic module is further promoted, and the flexible crystalline silicon photovoltaic module is especially suitable for application of the flexible crystalline silicon photovoltaic module which is easy to break.

Description

Technical Field

[0001] The present invention relates to a flexible photovoltaic module manufacturing technology, and in particular to a flexible interconnection structure of a battery string and a preparation method thereof. The present invention also relates to a photovoltaic module prepared by using the battery string. Background Art

[0002] With the development of economy and society, the demand for electricity is increasing. Solar energy is ubiquitous, inexhaustible, clean and pollution-free. It is the most ideal and sustainable renewable energy. Solar cells directly convert light energy into electrical energy, which is an important way to utilize solar energy.

[0003] At present, there are many types of solar cells, including crystalline silicon solar cells, perovskite solar cells, copper indium gallium selenide thin film solar cells, cadmium telluride thin film solar cells, gallium arsenide solar cells, etc. Affected by the material properties, the output voltage of these single solar cells is relatively low. In order to facilitate use, it is necessary to combine the single solar cells in series and parallel to form a photovoltaic module with a specific output current and voltage. At the same time, since solar cells are composed of a variety of semiconductor materials, PN junctions and various coatings are easily affected by harsh environments, especially silicon heterojunction solar cells (HJT) and perovskite solar cells (PSC) are more sensitive to water vapor. In order to enhance the ability of solar cells to resist the influence of harsh environments and increase their reliability in various environments, it is necessary to encapsulate and protect solar cells, that is, use encapsulation films, glass, backplanes and other encapsulation materials to encapsulate the series-parallel solar cells inside to form a protection device and improve the reliability of solar cells.

[0004] With the development of photovoltaic technology, there are more and more application scenarios, which puts forward clear requirements for the bendability of solar cells. At present, crystalline silicon solar cells occupy the absolute mainstream in the market. In order to achieve the flexible and bendable effect of mainstream crystalline silicon solar cells, the prior published patent applications CN202211090758X, CN202310136324.7, and CN202310175757.3 disclose methods for changing single crystal silicon from brittle to flexible, so that single crystal silicon solar cells have good flexibility. With the implementation and application of flexible crystalline silicon solar cells, it is found that there are still some technical difficulties, specifically: Crystalline silicon (especially single crystal silicon) solar cells have multiple functional layers, among which the metal electrode is the extraction channel for photogenerated carriers. During the use of solar cells, metal wires need to be connected to the metal electrodes of the solar cells to lead out the photogenerated carriers. Most existing technologies use copper-wrapped tin-lead, tin-lead-bismuth, and tin-bismuth-silver alloy welding strips to complete the interconnection of solar cells and then lead out the photogenerated carriers. During the welding process, the surface alloy of the welding strip forms an alloy layer with the metal electrode of the solar cell and adheres to the surface of the metal electrode to form a mechanical and electrical connection. However, due to the difference in mechanical properties between the welding strip and the crystalline silicon solar cell, the crystalline silicon solar cell is easily broken during the bending process of the flexible crystalline silicon solar cell.

[0005] Therefore, in the process of preparing and using flexible crystalline silicon solar cells and modules, how to avoid the stress concentration caused by bending during use and damage to crystalline silicon solar cells (that is, crystalline silicon photovoltaic modules) is a difficult problem that needs to be solved urgently. At the same time, in order to meet the welding requirements, crystalline silicon solar cells need to prepare large areas of silver main grid welding points, which wastes precious metal silver and increases production costs.

[0006] To this end, the applicant decided to seek a technical solution to solve the above technical problems based on the inventor's many years of dedicated research experience in this field. Summary of the invention

[0007] In view of this, the purpose of the present invention is to provide a flexible interconnection structure of a battery string and a preparation method thereof, and a photovoltaic module, which significantly improves the reliability of the flexible photovoltaic module, further promotes the process of large-scale promotion and application of flexible photovoltaic modules, and is particularly suitable for flexible crystalline silicon photovoltaic modules that are prone to breakage.

[0008] The technical solution adopted by the present invention is as follows: A flexible interconnection structure of a battery string includes a plurality of battery cells electrically connected by a metal interconnection strip, each battery cell including a first light-receiving surface and a second light-receiving surface; wherein the metal electrodes of the first light-receiving surface and the metal electrodes of the second light-receiving surface are respectively connected to the first metal interconnection strip and the second metal interconnection strip via strips of flexible transparent glue to form a flexible electrical connection structure.

[0009] Preferably, the first light-receiving surface is provided with a plurality of first fine grid metal wires distributed in parallel and at intervals, and the first fine grid metal wires serve as metal electrodes of the first light-receiving surface, and the first light-receiving surface is provided with or without a first main grid; and / or the second light-receiving surface is provided with a plurality of second fine grid metal wires distributed in parallel and at intervals, and the second fine grid metal wires serve as metal electrodes of the second light-receiving surface, and the second light-receiving surface is provided with or without a second main grid.

[0010] Preferably, the number of the first main gates is several, and they are intersecting with each first fine gate metal wire, wherein the first main gate uses one fine metal gate wire or multiple fine metal gate wires, and is continuous or discontinuous; the number of the second main gates is several, and they are intersecting with each second fine gate metal wire, wherein the second main gate uses one fine metal gate wire or multiple fine metal gate wires, and is continuous or discontinuous.

[0011] Preferably, the cell is a crystalline silicon solar cell or a copper indium gallium selenide thin-film solar cell or a cadmium telluride thin-film solar cell or a perovskite solar cell or a crystalline silicon-perovskite laminated solar cell or a gallium arsenide solar cell; preferably, a flexible crystalline silicon solar cell is used, and more preferably, a flexible monocrystalline silicon solar cell is used; wherein, the edge portion of the flexible monocrystalline silicon solar cell is selectively rounded so that the radius of curvature of the pyramid valley on the front, back and side of the edge is greater than 50nm; the radius of curvature of the edges, protrusions and grooves on the side is greater than 25nm, and the distance from the area where the edge is rounded to the edge of the flexible monocrystalline silicon solar cell is not greater than 5mm; for more preferred schemes of the flexible monocrystalline silicon solar cell involved in the present application, please directly refer to the relevant records of the prior published patent applications CN202211090758X, CN202310136324.7, and CN202310175757.3. This part is not the innovative content of the present invention, so it will not be explained in detail.

[0012] Preferably, the metal interconnection ribbon comprises a metal ribbon substrate and an anti-oxidation conductive coating coated on the outer periphery of the metal ribbon substrate; and / or the metal interconnection ribbon is flat or round, preferably flat.

[0013] Preferably, the metal strip substrate is made of a conductive metal, preferably Cu or Al; the anti-oxidation conductive coating has a melting point greater than 200° C., preferably Ag, Ni or Sn.

[0014] Preferably, the strip-shaped flexible transparent glue is usually non-conductive and can be any one or a mixture of epoxy resin glue, acrylic resin glue, silicone resin glue and modified silicone resin glue; after the strip-shaped flexible transparent glue is cured, a flexible electrical connection structure is formed between the metal electrode and its corresponding metal interconnection belt.

[0015] Preferably, a method for preparing the flexible interconnection structure of the battery string described above comprises the following steps: S1. A strip-shaped flexible transparent glue-metal interconnect tape adhesive is respectively arranged on the first light-receiving surface and the second light-receiving surface of a battery cell, wherein the strip-shaped flexible transparent glue-metal interconnect tape adhesive comprises a strip-shaped flexible transparent glue arranged on the corresponding light-receiving surface and a metal interconnect tape arranged on the strip-shaped flexible transparent glue; preferably, the strip-shaped flexible transparent glue can be printed or coated on the corresponding light-receiving surface by screen printing, inkjet printing or other known methods.

[0016] S2, applying pressure to the battery cell that has completed the above step S1), so as to squeeze the strip of flexible transparent glue located on the metal interconnection belt and its corresponding light-receiving surface, so as to form a point-shaped electrical connection between the metal interconnection belt and the metal electrode of its corresponding light-receiving surface; S3, performing the above steps S1) and S2) on other battery cells until the number of battery cells required for the battery string is connected to form a battery string; S4, heating the battery string obtained in the above step S3) so that at least part of the flexible transparent glue in the battery string is cured (the cured flexible transparent glue has the characteristics of flexibility, transparency and strong adhesion), so that the metal electrode of the first light-receiving surface and the metal electrode of the second light-receiving surface respectively form a flexible electrical connection with the first metal interconnection belt and the second metal interconnection belt; preferably, in this step S4), in order to facilitate the curing effect of the glue, the heating temperature is 50-250°C and the heating time is 1-30s. Specifically, the appropriate curing heating conditions can be selected according to the actual selected glue composition, and the present application does not impose any special restrictions on this; Preferably, a photovoltaic module comprises a first light-receiving surface packaging portion (usually comprising a first light-receiving surface packaging protective layer material and an adhesive film), a cell string layer and a second light-receiving surface packaging portion (usually comprising an adhesive film and a second light-receiving surface packaging protective layer material) laminated together, wherein the cell string layer adopts the cell string as described above or a cell string prepared by the preparation method of the flexible interconnection structure of the cell string as described above.

[0017] Preferably, the photovoltaic module has the property of being bendable and windable, and the bending radius is less than 30 cm.

[0018] It should be specially explained that the first light-receiving surface involved in the present invention may also be commonly referred to as the front surface, and the second light-receiving surface may also be commonly referred to as the back surface.

[0019] In order to further illustrate the lamination process of the photovoltaic module, the present application also particularly preferably proposes a method for preparing the photovoltaic module, comprising the following steps: (a1) laying a back side encapsulation protective layer material, an adhesive film, the battery string as described above, an adhesive film, and a front side encapsulation protective layer material on a rigid substrate in sequence; Further, the rigid substrate can be a rigid substrate of tempered glass, stainless steel plate, aluminum plate or other known materials; the back packaging protective layer material is preferably a single layer or composite layer material that is flexible and rollable and has high environmental tolerance, and is preferably ETFE, PVDF, a known photovoltaic back sheet, etc.; the adhesive film is preferably various known packaging adhesive films such as EVA, POE, EPE, etc.; the front packaging protective layer material is preferably a flexible and rollable, highly transparent, and environmentally tolerant material, and is preferably ETFE, PET, a known transparent photovoltaic composite board, etc.; (a2) placing the laid multi-layer flexible stacking material together with the rigid substrate into a laminator for lamination; (a3) After lamination is completed, the flexible photovoltaic module is removed from the rigid substrate and a junction box is installed to complete the preparation of the flexible photovoltaic module. Furthermore, various types of photovoltaic modules (also called "solar cells") can be produced according to the type of cells selected for the battery string, such as crystalline silicon solar cells, copper indium gallium selenide thin-film solar cells, cadmium telluride thin-film solar cells, perovskite solar cells, crystalline silicon / perovskite stacked solar cells, gallium arsenide solar cells, etc.

[0020] It should be noted that ETFE involved in the present invention is the abbreviation of ethylene-tetra-fluoro-ethylene, which means ethylene-tetrafluoroethylene copolymer in Chinese; PVDF is the abbreviation of polyvinylidene difluoride, which means polyvinylidene fluoride in Chinese; EVA is the abbreviation of ethylene-vinyl acetate copolymer, which means ethylene-vinyl acetate copolymer in Chinese; POE is the abbreviation of Polyolefin elastomer, which means polyolefin elastomer in Chinese; EPE film is a multilayer film made of POE and EVA through a co-extrusion process; PET is the abbreviation of Polyethylene terephthalate, which means polyethylene terephthalate in Chinese.

[0021] Compared with the output of photogenerated carriers of solar cells in the prior art, a metal welding strip is used to melt the metal of the welding strip coating at high temperature and weld it on the metal electrode of the solar cell, and an alloy is formed between the welding strip and the metal electrode (i.e., a hard connection structure). Due to the mechanical mismatch between the welding strip and the solar cell, during the bending process of the solar cell (especially the crystalline silicon solar cell), the stress of the solar cell is concentrated and fragmentation occurs, which affects the current output of the solar cell and the reliability of the component. To this end, the present invention creatively proposes to form a flexible electrical connection structure by correspondingly forming a strip of flexible transparent glue with the first metal interconnection strip and the second metal interconnection strip, that is, to establish an electrical connection relationship without molten metal alloy, and no hard connection is generated. The solidified strip of flexible transparent glue provides a stress release function for the solar cell (i.e., photovoltaic module), avoiding stress concentration caused by the difference in mechanical properties between the metal interconnection strip and the battery cell during the bending process of the photovoltaic module, which ultimately causes the battery cell to fragment, significantly improving the reliability of the flexible photovoltaic module, and further promoting the scale promotion and application of the flexible photovoltaic module, and is particularly suitable for the application of flexible crystalline silicon photovoltaic modules that are prone to fragmentation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a top view of a battery cell without a main grid in Example 1 of the present invention, where the following are marked: 1-silicon wafer, 2-fine grid metal wire; Figure 2 This is a top view of a cell in which the main grid is a thin metal grid line in Example 3 of the present invention, and the markings in the figure are: 1-silicon wafer, 201-thin grid metal line, 202-main grid; Figure 3 This is a top view of a cell in which the main grid is two thin metal grid lines spaced apart in Example 4 of the present invention, with the following marks: 1-silicon wafer, 201-thin grid metal line, 202-main grid; Figure 4 This is a top view of a cell in which the main grid is a discontinuous thin metal grid line in Example 5 of the present invention, and the markings in the figure are: 1-silicon wafer, 201-thin grid metal line, 202-main grid; Figure 5 It is a top view of a battery cell printed with a strip of flexible transparent glue in Example 1 of the present invention, and the markings in the figure are: 3-strip of flexible transparent glue; Figure 6 yes Figure 5 Cross-section of some structures; Figure 7 It is a top view of the first light-receiving surface and the second light-receiving surface of the battery cell in Example 1 of the present invention, in which the first metal interconnection belt and the second metal interconnection belt are placed correspondingly, and the mark in the figure is: 4-metal interconnection belt; Figure 8 yes Figure 7 Cross-section of some structures; Fig. 9 Yes Figure 7 A cross-sectional view of a portion of the structure after being placed in a press to extrude the metal interconnection ribbon; Fig.10 yes Fig. 9 Cross-sectional view in the AA direction; Fig.11 It is a cross-sectional view of the flexible photovoltaic prepared in Example 1 of the present invention (only a partial structural cross-section of the battery string layer is shown), and the markings in the figure are: 5-adhesive film on the back; 6-back packaging protective layer material. DETAILED DESCRIPTION

[0023] The present embodiment proposes a flexible interconnection structure of a battery string, including a plurality of battery cells electrically connected by a metal interconnection strip, each battery cell including a first light-receiving surface and a second light-receiving surface; wherein the metal electrode of the first light-receiving surface and the metal electrode of the second light-receiving surface are respectively connected to the first metal interconnection strip and the second metal interconnection strip via strips of flexible transparent glue to form a flexible electrical connection structure.

[0024] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] Embodiment 1: This embodiment 1 provides a method for preparing a flexible interconnection structure of a battery string. First, a number of flexible solar cells without a main grid (hereinafter referred to as "solar cells" or "cells") are prepared: This embodiment 1 specifically selects ultra-thin flexible crystalline silicon heterojunction solar cells, the thickness of the cell is in the range of 30-120μm, and the edge of the silicon wafer is processed by a brittle-to-flexible method (see the relevant implementation contents of the prior published patent applications: CN202211090758X, CN202310136324.7, CN202310175757.3) to make the solar cell flexible and bendable. The first light-receiving surface (front side) and the second light-receiving surface (back side) of the solar cell both have metal electrodes, and the metal electrodes are specifically fine grid metal wires. There is no main grid structure, please refer to Figure 1 As shown, 1 is a silicon wafer, and 2 is a fine gate metal line; In this embodiment 1, the method for preparing the flexible interconnection structure of the battery string includes the following implementation process: Print strips of flexible transparent glue on both sides of the solar cell: By screen printing, a strip of flexible transparent glue is printed on the first light-receiving surface and the second light-receiving surface of the solar cell respectively. The strip of flexible transparent glue is perpendicular to the direction of the fine grid metal wire on the solar cell. The glue is a non-conductive epoxy resin system thermosetting material. The width of the strip of flexible transparent glue is greater than the width of the fine grid metal wire, covering the fine grid metal wire and extending to cover the rest of the surface of the solar cell. The width of the strip of flexible transparent glue ranges from 10 to 500 μm and the height ranges from 1 to 100 μm. For details, please refer to Figure 5 and Figure 6 As shown; Place the first metal interconnection belt on the interconnection table, place the solar cell sheet printed with the strip of flexible transparent glue on the first metal interconnection belt, and use the positioning device to align the first metal interconnection belt with the center of the strip of flexible transparent glue on the first light-receiving surface of the solar cell; place the second metal interconnection belt on the second light-receiving surface of the solar cell sheet, and use the positioning device to align the second metal interconnection belt with the center of the strip of flexible transparent glue on the second light-receiving surface of the solar cell; The first metal interconnection belt and the second metal interconnection belt use the same metal interconnection belt. The metal interconnection belt is specifically a copper core coated with metal silver (i.e., a silver coating). The thickness of the silver coating ranges from 1 to 50 μm. The metal interconnection belt is flat in shape, with a width range of 0.1 to 1 mm and a thickness range of 0.05 to 0.25 mm. There can be a certain deviation between the position of the metal interconnection belt and the corresponding strip of flexible transparent glue. The maximum deviation is to ensure that the metal interconnection strip and the strip of flexible transparent glue have a minimum overlap of 10 to 50 μm. Please refer to the structure after placement. Figure 7 and Figure 8 As shown; placing a press to press the metal interconnection tape; A press is used to apply pressure to the solar cell sheet and the metal interconnection ribbon, so as to squeeze the glue (i.e., the strip-shaped flexible transparent glue) between the metal interconnection ribbon and the solar cell, and squeeze out the glue to form a point-shaped electrical connection between the metal interconnection ribbon and the metal electrode of the solar cell. At the same time, glue still exists in the glue area originally located between the metal electrode grid lines and between the metal interconnection ribbon and the solar cell sheet, so the metal interconnection ribbon is still firmly bonded. Please refer to Fig. 9 and Fig.10 shown.

[0026] The above steps (1), (2) and (3) are performed on other battery cells until the number of battery cells required for the battery string is connected, thereby obtaining a battery string (with a press) that achieves preliminary flexible interconnection; The solar cell string with the press obtained in step (3) above is placed in a heating furnace to heat and cure the glue, wherein the heating temperature is 200°C and the heating time is 10 seconds; the metal interconnection tape is bonded to the solar cell sheet, and the glue has flexibility, transparency and bonding ability after curing, so that a stable and reliable flexible electrical connection is formed between the metal interconnection tape and the metal electrode of the solar cell, thereby completing the battery string with a flexible interconnection structure.

[0027] Embodiment 2: This embodiment 2 provides a method for preparing a flexible photovoltaic module, comprising the following steps: (1) Using the battery string with a flexible interconnection structure provided in Example 1; (2) Laying the back packaging protective layer material (specifically using a transparent CPC photovoltaic composite back sheet), POE packaging film, flexible interconnected battery string, POE film, and front packaging protective layer material (specifically using a PVDF composite front sheet) on the rigid glass substrate in sequence, wherein the thickness of the composite back sheet is in the range of 50-500 μm, the thickness of the POE film is in the range of 50-600 μm, and the thickness of the composite front sheet is in the range of 50-500 μm; (3) The laid multi-layer flexible stacking material and the rigid substrate are placed into a laminator for lamination at a lamination temperature of 150°C and a lamination time of 30 minutes.

[0028] (4) After lamination, remove the flexible photovoltaic module from the rigid substrate and install the junction box to complete the preparation of the flexible photovoltaic module. For the cross-sectional structure of the flexible photovoltaic module, please refer to Fig.11 As shown; the flexible component has the characteristics of being bendable and windable, and the bending radius is less than 5cm.

[0029] Embodiment 3: The difference between Embodiment 3 and Embodiment 1 is that in Embodiment 3, the selected cell is provided with a main grid, wherein the main grid is a thin metal grid line, for details, see Figure 2 As shown, 201 is a fine gate metal line, and 202 is a main gate.

[0030] Embodiment 4: The difference between Embodiment 4 and Embodiment 1 is that in Embodiment 4, the selected cell is provided with a main grid, wherein the main grid is two thin metal grid lines spaced apart. For details, see Figure 3 As shown, 201 is a fine gate metal line, and 202 is a main gate.

[0031] Embodiment 5: The difference between Embodiment 5 and Embodiment 1 is that in Embodiment 5, the selected cell is provided with a main grid, wherein the main grid is a discontinuous thin metal grid line, and the adjacent main grid lines are staggered, so as to enhance the metal interconnection belt's ability to collect metal grid line carriers. For details, please refer to Figure 4 As shown, 201 is a fine gate metal line, and 202 is a main gate.

[0032] Example 6: The difference between Example 6 and Example 1 is that in Example 6, the selected solar cells are flexible gallium arsenide solar cells; printed strips of flexible transparent glue are respectively arranged on the first light-receiving surface and the second light-receiving surface of the solar cell by coating; the metal interconnection belt is a copper core coated with metal tin (i.e., a tin coating), the thickness of the tin coating ranges from 1-50μm, and the metal interconnection belt is circular, with a diameter width range of 0.1-0.3mm.

[0033] Example 7: The difference between Example 7 and Example 2 is that in Example 7, step (2) in the preparation of the flexible photovoltaic module is replaced by: using a back packaging protective layer material (specifically a transparent CPC photovoltaic composite back panel), an EVA packaging film, a flexible interconnected battery string, an EVA film, and a front packaging protective layer material (specifically an ETFE front panel), wherein the thickness of the composite back panel is in the range of 50-500 μm, the thickness of the EVA film is in the range of 50-600 μm, and the thickness of the front panel is in the range of 10-100 μm.

[0034] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0035] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A flexible interconnection structure of a battery string, comprising a plurality of battery cells electrically connected by a metal interconnection strip, characterized in that: Each battery cell includes a first light-receiving surface and a second light-receiving surface; wherein the metal electrode of the first light-receiving surface and the metal electrode of the second light-receiving surface respectively form a flexible electrical connection structure with the first metal interconnection belt and the second metal interconnection belt through strip-shaped flexible transparent glue.

2. The flexible interconnection structure of a battery string according to claim 1, characterized in that: The first light-receiving surface is provided with a plurality of first fine grid metal wires distributed in parallel and at intervals, and the first fine grid metal wires serve as metal electrodes of the first light-receiving surface, and the first light-receiving surface is provided with or without a first main grid; and / or the second light-receiving surface is provided with a plurality of second fine grid metal wires distributed in parallel and at intervals, and the second fine grid metal wires serve as metal electrodes of the second light-receiving surface, and the second light-receiving surface is provided with or without a second main grid.

3. The flexible interconnection structure of a battery string according to claim 2, characterized in that: The number of the first main gates is several, and they are intersecting with each first fine gate metal wire, wherein the first main gate uses one fine metal gate wire or multiple fine metal gate wires, and is continuous or discontinuous; the number of the second main gates is several, and they are intersecting with each second fine gate metal wire, wherein the second main gate uses one fine metal gate wire or multiple fine metal gate wires, and is continuous or discontinuous.

4. The flexible interconnection structure of a battery string according to claim 1, characterized in that: The solar cell is a crystalline silicon solar cell, a copper indium gallium selenide thin film solar cell, a cadmium telluride thin film solar cell, a perovskite solar cell, a crystalline silicon-perovskite stacked solar cell, or a gallium arsenide solar cell; preferably, a flexible crystalline silicon solar cell is used, and more preferably, a flexible single crystal silicon solar cell is used.

5. The flexible interconnection structure of a battery string according to claim 1, characterized in that: The metal interconnection ribbon comprises a metal ribbon substrate and an anti-oxidation conductive coating coated on the outer periphery of the metal ribbon substrate; and / or the metal interconnection ribbon is flat or round, preferably flat.

6. The flexible interconnection structure of a battery string according to claim 5, characterized in that: The metal strip substrate is made of conductive metal, preferably Cu or Al; the anti-oxidation conductive coating has a melting point greater than 200° C., preferably Ag, Ni or Sn.

7. The flexible interconnection structure of a battery string according to claim 1, characterized in that: The strip-shaped flexible transparent glue is non-conductive and is made of any one or a mixture of epoxy resin glue, acrylic resin glue, silicone resin glue and modified silicone resin glue; after the strip-shaped flexible transparent glue is cured, a flexible electrical connection structure is formed between the metal electrode and its corresponding metal interconnection belt.

8. A method for preparing a flexible interconnection structure of a battery string according to any one of claims 1 to 7, characterized in that: The steps include: S1. Arranging a strip-shaped flexible transparent glue-metal interconnection tape adhesive body on a first light-receiving surface and a second light-receiving surface of a battery cell, respectively, wherein the strip-shaped flexible transparent glue-metal interconnection tape adhesive body comprises a strip-shaped flexible transparent glue arranged on the corresponding light-receiving surface and a metal interconnection tape arranged on the strip-shaped flexible transparent glue; S2, applying pressure to the battery cell that has completed the above step S1), so as to squeeze the strip of flexible transparent glue located on the metal interconnection belt and its corresponding light-receiving surface, so as to form a point-shaped electrical connection between the metal interconnection belt and the metal electrode of its corresponding light-receiving surface; S3, performing the above steps S1) and S2) on other battery cells until the number of battery cells required for the battery string is connected to form a battery string; S4, heating the battery string obtained in the above step S3) to solidify at least part of the flexible transparent glue in the battery string, so that the metal electrode on the first light-receiving surface and the metal electrode on the second light-receiving surface form flexible electrical connections with the first metal interconnection belt and the second metal interconnection belt respectively.

9. A photovoltaic module, comprising a first light-receiving surface encapsulation portion, a battery string layer and a second light-receiving surface encapsulation portion laminated together, characterized in that: The battery string layer is a battery string prepared by using the battery string as claimed in any one of claims 1 to 7 or a battery string prepared by using the method for preparing a flexible interconnection structure of a battery string as claimed in claim 8.

10. The photovoltaic module according to claim 9, characterized in that: The photovoltaic module has the characteristic of being bendable and windable, and the bending radius is less than 30 cm.

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