Flexible thin film solar cell shingle interconnection structure, fabrication process and module

Abstract

This invention relates to a flexible thin-film solar cell shingled interconnect structure, fabrication process, and module. The structure includes multiple sub-cells, each comprising a substrate layer, a first electrode layer, a device layer, a second electrode layer, a bus layer, and an interconnection layer. On one hand, this invention addresses the low internal loss and high conversion efficiency of shingled interconnects for non-conductive flexible substrate thin-film solar cells. It not only avoids short circuits or leakage between electrode layers but also eliminates the effects of deformation and flatness caused by the flexible substrate. Furthermore, based on increased current, reduced interconnect resistance, and lower power loss, it perfectly matches the output characteristics of current mainstream modules, significantly reducing module costs. Simultaneously, the larger interconnection contact area at the bends creates better ohmic contacts, improving collection efficiency and significantly increasing the fill factor. On the other hand, for modules of the same size, the shingled interconnect structure allows for a larger effective area, directly increasing the module photocurrent and thus significantly improving module efficiency.

Description

Technical Field

[0001] This invention belongs to the field of solar cells, specifically relating to a flexible thin-film solar cell shingled interconnection structure, as well as a fabrication process for the flexible thin-film solar cell shingled interconnection structure and a flexible thin-film solar cell shingled module. Background Technology

[0002] Currently, most flexible thin-film solar cells are fabricated on substrates of ultra-thin flexible glass and polymer-based materials. Because these substrates are non-conductive, it is difficult to achieve interconnection via top-to-bottom bonding like traditional crystalline silicon solar cells during module manufacturing. Therefore, for flexible thin-film solar cells on non-conductive substrates, a three-stage scribing interconnection process is generally required to meet practical application needs. The modules are interconnected after large-area cells are divided into several sub-cell units using laser or mechanical scribing. The specific interconnection process is as follows: First, the transparent conductive oxide (TCO) layer on the substrate is scribed into several small sections, forming the P1 scribing; then, a P / N type functional layer, an intrinsic absorption layer, and an N / P type functional layer are deposited to form the device layer for photoelectric conversion. Next, the device layer is scribed parallel to the P1 scribing at the same distance as possible, forming the P2 scribing; finally, after depositing the TCO / metal electrode layer, the device layer is scribed parallel to the P2 scribing at the same distance as possible, forming the P3 scribing. This completes the series connection of several sub-cells.

[0003] However, this method of segmented interconnection has the following problems:

[0004] 1) The scribing process is complex and requires high processing precision. In addition to the control of the equipment itself, the deformation and flatness of the substrate itself also have high requirements. However, due to the characteristics of flexible substrates, it is difficult to achieve stability in these requirements as with rigid glass substrates. Therefore, the scribing process is very challenging to use in the preparation of flexible thin-film solar cells.

[0005] 2) The limited contact interconnect current flux cross section and the Schottky barrier of the gold-metal interface of TCO / metal at the P2 line will inevitably result in a high contact resistance (i.e., the internal resistance of the sub-cell string). Therefore, it is necessary to control the sub-cell area and minimize the cell string current to reduce internal losses. This will limit the overall electrical output characteristics and application scenarios of the module.

[0006] 3) The scribing process will cause a certain degree of damage to the film layer, leaving unreleased stress at the scribing point. When the flexible battery is bent, under the influence of external strain, the stress release will cause irreversible damage to the film layer.

[0007] 4) The area removed by laser scribing and the adjacent scribing areas constitute a "dead zone," which reduces the effective power generation area of ​​the module, thereby reducing the overall output power and the conversion efficiency of the entire area of ​​the module. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an improved flexible thin-film solar cell shingled interconnect structure.

[0009] It also relates to a fabrication process for a flexible thin-film solar cell shingled interconnect structure, and a flexible thin-film solar cell shingled module.

[0010] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0011] A flexible thin-film solar cell shingled interconnect structure includes multiple sub-cells. Each sub-cell includes a substrate layer, a first electrode layer, a device layer, a second electrode layer, and a busbar layer. A first interconnection portion and a second interconnection portion are formed on opposite sides of each sub-cell. The substrate layer, first electrode layer, device layer, second electrode layer, and busbar layer of each sub-cell are aligned with one interconnection side to form the first interconnection portion. Taking the other interconnection side of the busbar layer as a reference, the other interconnection side of the second electrode layer, device layer, first electrode layer, and substrate layer extends outward layer by layer from top to bottom to form interconnection side edges. The interconnection sides of the first electrode layer and the substrate layer are bent downward and inward and attached to the bottom of the substrate layer to form a folded portion. The reference side, the interconnection side, and the folded portion constitute a second interconnection portion. The sub-cell also includes an interconnection layer covering the entire surface of the first electrode layer of the folded portion. The interconnection layer and the bus layer are insulated from each other. Each sub-cell is tilted upward from the second interconnection portion. The interconnection layer extending from the bottom of the second interconnection portion of the previous sub-cell overlaps the top interconnection side of the bus layer of the first interconnection portion of the next sub-cell to form a battery string through a shingled interconnection.

[0012] Preferably, the epitaxial side of the second electrode layer is aligned with the epitaxial side of the device layer; more preferably, the first electrode layer, the substrate layer, and the interconnect layer are aligned from the inner epitaxial side of the bend. Here, based on the design of the first interconnect portion and the second interconnect portion, not only is interconnect assembly convenient, but short circuits caused by the connection between the first electrode layer and the second electrode layer can also be avoided.

[0013] According to a specific embodiment and preferred aspect of the invention, the inner width of the folded portion is greater than the width of the interconnect side of the second electrode layer. This avoids an excessively narrow inner width leading to a small interconnect contact area, thereby forming a better ohmic contact based on a larger interconnect contact area, improving collection efficiency, significantly increasing the fill factor, and further increasing the stability of the interconnection between the two battery strings.

[0014] According to another specific embodiment and preferred aspect of the invention, the bus layer includes a cover segment located on the interconnect side and covering the corresponding side of the second electrode layer, and multiple bus bars arranged side-by-side on the second electrode layer and communicating with the cover segment. The ends of the multiple bus bars away from the cover segment are aligned, and the aligned end faces constitute a reference side surface. The extensional width formed by the second electrode layer is the insulation width between the interconnect layer and the bus layer. Based on the larger interconnect contact area formed by the cover segment, the collection efficiency is improved, and the fill factor is significantly increased.

[0015] In some specific implementations, the width of the covering section is greater than or equal to the inner extension width of the bend. This satisfies the required interconnection contact area while also facilitating the implementation of the shingled structure.

[0016] In some specific embodiments, the tilt angles of each sub-cell are the same, and in the shingled interconnection, the interconnection layer at the bottom of the bent portion is connected to the top interconnection side of the bus layer of the first interconnection portion based on conductive adhesive. The conductive adhesive forms a conductive circuit and provides positioning bonding, maintaining the formed cell string in a shingled arrangement for sequential assembly.

[0017] Another technical solution of the present invention: a fabrication process for a flexible thin-film solar cell shingled interconnect structure, comprising the following steps:

[0018] S1, Preparation of Sub-cells

[0019] First, a flexible substrate is selected as the substrate layer, and a first electrode layer, a device layer, and a second electrode layer are sequentially formed on the surface of the substrate layer. Second, with the opposite sides of the resulting structural layer as interconnect sides, and taking one interconnect side as a reference, the film layer on the upper part of the first electrode layer is removed by edge cutting, and the first electrode layer and the substrate layer are epitaxially formed to form interconnect sides. Next, an interconnect connection layer is deposited to fully cover the interconnect side of the first electrode layer, and a bus layer is formed on the second electrode layer. The cut sides of the second electrode layer and the device layer are epitaxially formed relative to the bus layer to form interconnect sides. The interconnect connection layer and the bus layer are insulated and staggered. The uncut substrate layer, the first electrode layer, the device layer, the second electrode layer, and the bus layer are aligned from the interconnect side to form a first interconnect portion. Finally, based on the first electrode layer, the substrate layer, and the interconnect connection layer, a bent-over portion is formed by bending downward and inward from the corresponding interconnect side to form a bent-over portion that adheres to the substrate layer. The bent-over portion, the interconnect side of the device layer and the second electrode layer, and the spaced side of the bus layer form a second interconnect portion.

[0020] S2, Shingled Interconnect

[0021] In step S1, the sub-cell is tilted upward from the second interconnection section, and the interconnection layer extending from the bottom of the second interconnection section of the previous sub-cell overlaps with the top interconnection side of the busbar layer of the first interconnection section of the next sub-cell to form a battery string through a shingled interconnection.

[0022] Preferably, the structural layer is a single unit, or it is based on a full-size battery cut into several sub-units, and then each sub-unit is formed with a first interconnection portion and a second interconnection portion. Cutting from a full-size battery can form the required individual sub-cells, and each sub-cell can be cut and processed to form the required second interconnection portion. Therefore, the processing efficiency is increased exponentially. At the same time, the cutting method includes, but is not limited to, any one of laser, scribing knife, gate knife, scissors, etc., and the cutting must ensure that the damage to the battery is minimized and that the connection between the first electrode layer and the second electrode layer at the edge is not short-circuited.

[0023] Preferably, in step S1, the flexible substrate is made of ultrathin flexible glass or a polymer, wherein the polymer is any one or more of polyethylene terephthalate, polyethylene naphthalate, polyimide, poly(p-xylylene), and polycarbonate; if the surface of the substrate layer formed by the flexible substrate is the light-receiving surface of the battery, the first electrode layer is a transparent conductive oxide; if the surface of the substrate layer is not used as the light-receiving surface of the battery, the first electrode layer is a transparent conductive oxide, a metal, or a composite stack of a metal and a transparent conductive oxide.

[0024] In some specific embodiments, the transparent conductive oxide includes, but is not limited to, any one or more of fluorine-doped tin oxide, tin-doped indium oxide, zinc-doped indium oxide, aluminum-doped zinc oxide, indium oxide with tungsten, titanium-doped tin indium oxide, boron-doped zinc oxide, and cerium-doped indium oxide; and / or, the metal includes, but is not limited to, one or more of copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, and manganese.

[0025] In short, the substrate material is a non-conductive flexible substrate, including but not limited to ultra-thin flexible glass (UTG) and polymers, wherein the polymer is any one or a combination of at least two of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), parylene, and polycarbonate (PC). If one side of the substrate material is the light-receiving surface of the battery, the first electrode layer is a transparent conductive oxide (TCO), including but not limited to any one or a combination of at least two of FTO (fluorine-doped tin oxide), ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), AZO (aluminum-doped zinc oxide), IWO (indium tungsten oxide), ITIO (titanium-doped tin indium oxide), BZO (boron-doped zinc oxide), or ICO (cerium-doped indium oxide). If the substrate material side is not used as the light-receiving surface of the battery, the first electrode layer, in addition to the aforementioned transparent conductive oxide, may also be any one or at least two combinations or alloys of high-conductivity metals and alloys such as copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, and manganese, or a composite stacked structure of metal and TCO.

[0026] According to another specific embodiment and preferred aspect of the present invention, in step S1, the deposition method of the first electrode layer includes, but is not limited to, any one of vacuum evaporation, magnetron sputtering, reactive plasma deposition, chemical vapor deposition, screen printing, electroplating, and transfer printing; and the thickness of the formed first electrode layer is 10-1000 nm; and / or, in step S1, the material of the device layer is amorphous silicon germanium, copper indium gallium selenide, cadmium telluride, gallium arsenide, or perovskite; and / or, the deposition method of the device layer includes, but is not limited to, any one of vacuum evaporation, magnetron sputtering, reactive plasma deposition, chemical vapor deposition, screen printing, electroplating, coating, spraying, printing, near-space sublimation deposition, and vapor transport deposition. One method; and / or, in step S1, the cutting method is laser and / or mechanical scribing, and the upper film layer is removed based on the surface of the first electrode layer to form a corresponding interconnect side, wherein the first electrode layer and the substrate layer are aligned, and the width of the corresponding interconnect side is at least 50 μm, and the interconnect connection layer fully covers the corresponding interconnect side; and / or, the second electrode layer and the interconnect side of the device layer are aligned, and the width of the formed interconnect side is at least 50 μm; and / or, the bus layer and the interconnect connection layer are both metallized patterned layers, wherein the metallized patterned layer includes a gate layer and / or a cover plate layer, and the material used for the metallized patterned layer includes, but is not limited to, one or more of copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, and manganese.

[0027] In short, all film layers above the first electrode layer are removed to obtain the electrode connection area. The width of the removed area should be minimized, but the width of the area serving as the electrode interconnect should be considered to allow for sufficient flux, generally ≥50μm. The larger the cell area, i.e., the larger the string current, the larger the electrode connection area should theoretically be. The removal methods include, but are not limited to, any one or at least a combination of two of laser and mechanical scribing. The insulation width between the interconnect layer and the bus layer should generally be ≥50μm, i.e., the risk of leakage between electrodes should be completely avoided, and determined according to the process conditions and the electrical output characteristics of the interconnected product. In short, the width, number, and spacing of the grid lines are designed based on the light reception requirements of the product on that surface. If the surface does not require light reception, it can be a gapless, completely covered film layer. Metallic materials include, but are not limited to, any one or at least a combination of two of high-conductivity metals and alloys such as copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, and manganese. Meanwhile, the grid line structure is patterned using a mask or stencil according to the component packaging design. The deposition method of the back electrode leading grid line includes, but is not limited to, any one of vacuum evaporation, magnetron sputtering, reactive plasma deposition, chemical vapor deposition, screen printing, electroplating, and transfer printing.

[0028] Another technical solution of the present invention: a flexible thin-film solar cell shingled module, comprising the above-mentioned cell strings and guide strips, wherein there are multiple cell strings, and a gap is formed between each two adjacent cell strings, and the gap width is ≥50μm. The guide strips connect the first interconnection part and the second interconnection part of the multiple cell strings located on the same side respectively, wherein the connection method is parallel or series.

[0029] Due to the implementation of the above technical solutions, the present invention has the following advantages compared with the prior art:

[0030] In existing flexible thin-film solar cells, the scribing and segmentation interconnection process presents several challenges. First, the scribing process is complex and requires high precision. Besides equipment control, the substrate's deformation and flatness are also critical. However, the inherent characteristics of flexible substrates make it difficult to maintain stability in these aspects compared to rigid glass substrates. Therefore, applying the scribing process to flexible thin-film solar cell fabrication presents significant challenges. Second, the limited contact interconnect current flux cross-section at the P2 scribing point and the Schottky barrier at the TCO / metal interface inevitably result in high contact resistance (i.e., sub-cell string internal resistance), necessitating careful control of the scribing process. The design of the sub-cell area aims to minimize the cell string current and reduce internal losses, which limits the overall electrical output characteristics and application scenarios of the module. Furthermore, the laser marking process causes some damage to the film layer, leaving unreleased stress at the marking points. When the flexible cell is bent, the stress release under external strain causes irreversible damage to the film layer. In addition, the area removed by laser marking and adjacent areas constitute "dead zones," reducing the effective power generation area of ​​the module, thereby reducing the overall output power and overall conversion efficiency. This invention addresses these shortcomings by comprehensively designing the flexible thin-film solar cell shingled interconnect structure. This invention cleverly addresses the shortcomings and defects of existing technologies. By adopting this flexible thin-film solar cell shingled interconnect structure, based on the design of the first and second interconnect portions formed by the flexible thin-film solar cell itself, and with the interconnection layer extending from the bottom of the second interconnect portion of the preceding sub-cell overlapping the top interconnection side of the busbar layer of the first interconnect portion of the following sub-cell, a battery string is formed through shingled interconnection. Therefore, this invention addresses the low internal loss and high conversion efficiency of shingled interconnection for non-conductive flexible substrate thin-film solar cells, not only avoiding short circuits or leakage between electrode layers but also eliminating the deformation and flatness issues caused by the flexible substrate. The flexible thin-film solar cell module is not only less affected by temperature, but also achieves better ohmic contact due to increased current, reduced interconnect resistance and power loss, fully matching the output characteristics of current mainstream modules, significantly reducing module costs. At the same time, the larger interconnect contact area of ​​the shingled section forms a better ohmic contact, improving collection efficiency and significantly increasing the fill factor. On the other hand, for modules of the same size, the shingled interconnect can obtain a larger effective area, directly increasing the module photocurrent and thus greatly improving module efficiency. In addition, the cell and module sizes can be freely and flexibly customized according to needs, with a uniform and beautiful appearance, greatly expanding the application fields of flexible thin-film solar cell modules. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the sub-cell structure of the flexible thin-film solar cell shingled interconnection structure in Example 1;

[0032] Figure 2 for Figure 1 Front view diagram;

[0033] Figure 3 for Figure 2 A top-down view;

[0034] Figure 4 for Figure 1 Schematic diagram of a neutron cell forming process;

[0035] Figure 5 for Figure 4 Front view schematic diagram of a neutron cell after molding;

[0036] Figure 6 This is a front view schematic diagram of the interconnected two sub-cells in Example 1;

[0037] Figure 7 This is a front view schematic diagram of the flexible thin-film solar cell shingled module of Example 2;

[0038] Figure 8 for Figure 7 A top-down view;

[0039] Figure 9 This is a front view schematic diagram of the flexible thin-film solar cell shingled assembly of Example 3;

[0040] Wherein: G, sub-cell; g1, first interconnect; g2, second interconnect; 1, substrate layer; 2, first electrode layer; 3, device layer; 4, second electrode layer; 5, bus layer; 50, cover plate layer; 51, grid line; 6, interconnection layer; W, bend; s, current guide. Detailed Implementation

[0041] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0042] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0044] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0046] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation. Example 1

[0047] like Figures 1 to 6 As shown, the flexible thin-film solar cell shingled interconnect structure involved in this embodiment includes multiple sub-cells G, each sub-cell G including a substrate layer 1, a first electrode layer 2, a device layer 3, a second electrode layer 4, a bus layer 5, and an interconnection layer 6.

[0048] Specifically, a first interconnection portion g1 and a second interconnection portion g2 are formed on opposite sides of the sub-cell G, respectively. The substrate layer 1, the first electrode layer 2, the device layer 3, the second electrode layer 4, and the bus layer 5 are aligned on one interconnection side (left side) to form the first interconnection portion g1. Taking the other interconnection side (right side) of the bus layer 5 as a reference, the second electrode layer 4, the device layer 3, the first electrode layer 2, and the other interconnection side (right side) of the substrate layer 1 extend outwards layer by layer from top to bottom to form interconnection sidewalls. The interconnection sidewalls of the first electrode layer 2 and the substrate layer 1 are bent downwards and inwards and adhere to the bottom of the substrate layer to form a bent portion W. The reference sidewall, the interconnection sidewalls, and the bent portion constitute the second interconnection portion g2. An interconnection layer 6 covers the entire surface of the first electrode layer 2 in the bent portion W, and the interconnection layer 6 and the bus layer 5 are insulated from each other.

[0049] In this example, the epitaxial side of the second electrode layer 4 is aligned with the epitaxial side of the device layer 3, and the width of the interconnect side formed by the two is the insulation width between the interconnect layer 6 and the bus layer 5, which is at least 50 μm. The first electrode layer 2, the substrate layer 1, and the interconnect layer 6 are aligned with the inner epitaxial side of the bend.

[0050] In some specific embodiments, the inner width of the bent portion W is greater than the width of the interconnect side of the second electrode layer 4, and is separated from the inner side of the reference side and the top and bottom of the bus layer 5. This avoids the interconnect contact area being too small due to an excessively narrow inner width, thereby forming a better ohmic contact based on a larger interconnect contact area, improving collection efficiency, significantly increasing the fill factor, and further increasing the stability of the interconnection between the two battery strings.

[0051] Bus layer 5 is a metallized patterned layer, which includes a cover layer 50 located on the interconnect side and covering the corresponding side of the second electrode layer 4, and multiple gate lines 51 arranged side-by-side on the second electrode layer 4 and connected to the cover layer 50. The multiple gate lines 51 extend in alignment away from the end of the cover layer 50, and the aligned end faces constitute the reference side faces. The outer width formed by the second electrode layer 4 is the insulation width between the interconnect connection layer 6 and the bus layer 5. Based on the larger interconnect contact area formed by the cover layer 50, the collection efficiency is improved and the fill factor is significantly improved. At the same time, the width of the cover layer 50 is equal to the inner width of the bend W. This satisfies the required interconnect contact area and also facilitates the implementation of shingling. Furthermore, the interconnect connection layer 6 is also a metallized patterned layer, and in this example, it is formed on the surface of the first electrode layer 2 in a fully covering manner.

[0052] In some specific embodiments, the fabrication process of the flexible thin-film solar cell shingled interconnect structure includes the following steps:

[0053] S1, Preparation of sub-cells

[0054] First, a flexible substrate is selected as the substrate layer 1, and a first electrode layer 2, a device layer 3, and a second electrode layer 4 are sequentially formed on the surface of the substrate layer 1. Second, using the opposite sides of the resulting structural layers as interconnect sides, and taking one interconnect side as a reference, edge cutting is performed to remove the film layer on top of the first electrode layer 2, thus forming interconnect sides between the first electrode layer 2 and the substrate layer 1. Next, an interconnect connection layer 6 is deposited to fully cover the interconnect sides of the first electrode layer 2, while a bus layer 5 is formed on the second electrode layer 4, wherein the cut sides of the second electrode layer 4 and the device layer 3 are adjacent to each other. Interconnect sides are formed on the epitaxial side of bus layer 5. Interconnect layer 6 and bus layer 5 are insulated and staggered. Uncut substrate layer 1, first electrode layer 2, device layer 3, second electrode layer 4 and bus layer 5 are aligned from the interconnect side to form first interconnect portion g1. Finally, based on the first electrode layer 2, substrate layer 1 and interconnect layer 6, bend downward and inward from the corresponding interconnect side to form a bent portion W that is attached to the substrate layer. The bent portion W, the interconnect side of device layer 3 and second electrode layer 4 and the spacer side of bus layer 5 form second interconnect portion g2.

[0055] S2, Shingled Interconnect

[0056] In step S1, the sub-battery G is tilted upward from the second interconnection part g2, and the interconnection layer 6 extending from the bottom of the second interconnection part g2 of the previous sub-battery G overlaps the top interconnection side of the bus layer 5 of the first interconnection part g1 of the subsequent sub-battery G to form a battery string through a shingled interconnection.

[0057] In some specific embodiments, each sub-cell G has the same tilt angle, and in the shingled interconnection, the interconnection layer 6 at the bottom of the bent portion is connected to the top interconnection side of the bus layer 5 of the first interconnection portion g1 based on conductive adhesive. The conductive adhesive forms a conductive circuit and provides positioning bonding, maintaining the formed battery string in a shingled arrangement for sequential assembly. Simultaneously, the structural layer is a single unit, or it can be based on a full-size battery cut into several sub-units, and then the first and second interconnection portions are formed on each sub-unit. Cutting from a full-size battery allows for the formation of the required individual sub-cells, thereby cutting and processing each sub-cell to form the required second interconnection portion. Therefore, the processing efficiency is increased exponentially. The cutting methods include, but are not limited to, any one of laser, scribing knife, gate blade, scissors, etc., and the cutting must ensure minimal damage to the battery and avoid short-circuiting the connection between the first and second electrode layers at the edges.

[0058] In this example, in step S1, the flexible substrate is made of ultrathin flexible glass or a polymer, wherein the polymer is any one or more of polyethylene terephthalate, polyethylene naphthalate, polyimide, poly(p-xylylene), and polycarbonate; the surface of the substrate layer 1 formed based on the flexible substrate is the light-receiving surface of the battery, and the first electrode layer 2 is a transparent conductive oxide; the surface of the substrate layer 1 is not used as the light-receiving surface of the battery, and the first electrode layer 2 is a transparent conductive oxide, a metal, or a composite stack of a metal and a transparent conductive oxide. In some specific embodiments, the transparent conductive oxide includes, but is not limited to, any one or more of fluorine-doped tin oxide, tin-doped indium oxide, zinc-doped indium oxide, aluminum-doped zinc oxide, indium oxide with tungsten, titanium-doped tin indium oxide, boron-doped zinc oxide, or cerium-doped indium oxide; and / or, the metal includes, but is not limited to, one or more of copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, and manganese. In short, the substrate material is a non-conductive flexible substrate, including but not limited to ultra-thin flexible glass (UTG) or polymers, wherein the polymer is any one or a combination of at least two of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), parylene, polycarbonate (PC), etc. If one side of the substrate material is the light-receiving surface of the battery, the first electrode layer 2 is a transparent conductive oxide (TCO), including but not limited to any one or a combination of at least two of FTO (fluorine-doped tin oxide), ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), AZO (aluminum-doped zinc oxide), IWO (indium tungsten oxide), ITIO (titanium-doped tin indium oxide), BZO (boron-doped zinc oxide), or ICO (cerium-doped indium oxide). If the substrate material side is not used as the light-receiving surface of the battery, the first electrode layer 2, in addition to the aforementioned transparent conductive oxide, can also be any one or a combination of at least two of high-conductivity metals and alloys, including but not limited to metals such as copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, and manganese, or a composite stacked structure of metal and TCO. The deposition method of the first electrode layer 2 includes, but is not limited to, vacuum evaporation, magnetron sputtering, reactive plasma deposition, chemical vapor deposition, screen printing, electroplating, and transfer printing; and the thickness of the formed first electrode layer 2 is 10-1000 nm.

[0059] In step S1, the material of device layer 3 is amorphous silicon germanium, copper indium gallium selenide, cadmium telluride, gallium arsenide, or perovskite; and / or, the deposition method of device layer 3 includes, but is not limited to, any one of vacuum evaporation, magnetron sputtering, reactive plasma deposition, chemical vapor deposition, screen printing, electroplating, coating, spraying, printing, near-space sublimation deposition, and vapor transport deposition.

[0060] In step S1, the cutting method is laser and / or mechanical scribing, and the upper film layer is removed based on the surface of the first electrode layer 2 to form the corresponding interconnect side. The first electrode layer 2 is aligned with the substrate layer 1, and the width of the corresponding interconnect side is at least 50 μm. The interconnect connection layer 6 fully covers the corresponding interconnect side. The second electrode layer is aligned with the interconnect side of the device layer, and the width of the formed interconnect side is at least 50 μm. Both the bus layer 5 and the interconnect connection layer 6 are metallized patterned layers, which include gate line layers and / or cover plates. The materials used for the metallized patterned layers include, but are not limited to, one or more of copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, and manganese. In short, all film layers above the first electrode layer 2 are removed to obtain the electrode connection area. The width of the removed area should be minimized, but the width of the area as the electrode interconnect should be considered to obtain sufficient flux. Generally, the width is ≥50 μm. The larger the area of ​​the battery, i.e., the larger the string current, the larger the electrode connection area should theoretically be. The removal method includes, but is not limited to, any one or a combination of at least two of laser and mechanical scribing. The insulation width between interconnect layer 6 and bus layer 5 should generally be ≥50μm, meaning that the risk of leakage between electrodes should be completely avoided. This width is also determined based on the process conditions and the electrical output characteristics of the interconnected product. In short, the width, number, and spacing of the gate lines are designed according to the light reception requirements of the product on that surface. If the surface does not require light reception, it can be a gapless, completely covered film layer. Metal materials include, but are not limited to, any one or at least two combinations or alloys of high-conductivity metals and alloys such as copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, and manganese. The metallization pattern layer is patterned using a mask or stencil according to the component packaging design. The deposition method for the back electrode leading gate lines includes, but is not limited to, any one of vacuum evaporation, magnetron sputtering, reactive plasma deposition, chemical vapor deposition, screen printing, electroplating, and transfer printing. Example 2

[0061] Combination Figure 7 and Figure 8 As shown, this embodiment relates to a flexible thin-film solar cell shingled module, which includes the battery strings and the current guide strips s involved in Embodiment 1. There are multiple battery strings, and a gap is formed between each two adjacent battery strings, with a gap width ≥ 50 μm. The current guide strips s connect the first interconnection part g1 and the second interconnection part g2 of the multiple battery strings located on the same side, respectively, wherein the connection method is parallel or series.

[0062] Specifically, the interconnection structure of Example 1 is adopted, with sub-cell size: 190*107.5mm (effective cell area 190*97.5mm), number of sub-cells: 36, module size: 1200*600mm, and the preparation steps are as follows:

[0063] S1, Preparation of sub-cells

[0064] First, a flexible substrate is selected as the substrate layer 1, and a first electrode layer 2, a device layer 3, and a second electrode layer 4 are sequentially formed on the surface of the substrate layer 1. Second, using the opposite sides of the resulting structural layers as interconnect sides, and taking one interconnect side as a reference, edge cutting is performed to remove the film layer on top of the first electrode layer 2. The first electrode layer 2 and the substrate layer 1 are epitaxially formed to form interconnect sides. That is, the electrode connection area is obtained by etching the film surface using a picosecond green laser, wherein the width of the electrode connection area is the width of the interconnect side, and the width is 10 mm. Next, an interconnect connection layer 6 is deposited to fully cover the interconnect side of the first electrode layer 2, while simultaneously depositing an interconnect connection layer 6 on the second electrode layer 4. A bus layer 5 is formed, wherein the cut sides of the second electrode layer 4 and the device layer 3 extend outward relative to the bus layer 5 to form interconnect sides. The interconnect connection layer 6 is insulated from and staggered from the bus layer 5. The uncut substrate layer 1, the first electrode layer 2, the device layer 3, the second electrode layer 4, and the bus layer 5 are aligned from the interconnect side to form a first interconnect portion g1. Finally, based on the first electrode layer 2, the substrate layer 1, and the interconnect connection layer 6, a bent portion W is formed by bending downward and inward from the corresponding interconnect side to form a bent portion W attached to the substrate layer. The bent portion W, the interconnect side of the device layer 3 and the second electrode layer 4, and the spaced side of the bus layer 5 form a second interconnect portion g2.

[0065] S2, Shingled Interconnect

[0066] In step S1, the sub-battery G is tilted upward from the second interconnection part g2, and the interconnection connection layer 6 extending from the bottom of the second interconnection part g2 of the previous sub-battery G is fixed to the top interconnection side of the bus layer 5 of the first interconnection part g1 of the next sub-battery G based on conductive adhesive to form a battery string through a shingled interconnection.

[0067] S3, Component Assembly

[0068] First, the sub-cells are grouped into strings of 12, and three strings are laid in parallel with a 100μm gap between adjacent strings. Then, a guide strip s is used to connect and lead out the first interconnection g1 of the three sub-cells G on one side of the three strings, and another guide strip s is used to connect and lead out the second interconnection g2 of the three sub-cells G. The contact points are ultrasonically welded, and the three series-connected battery strings are connected in parallel. Second, a POE film is laid, and butyl rubber strips are laid at the edges. Finally, the flexible PET barrier front panel and back panel are laminated together to obtain a flexible perovskite module. Example 3

[0069] Combination Figure 9As shown, this embodiment relates to a flexible thin-film solar cell shingled module, which has a structure that is basically the same as that of embodiment 3. The difference is that the width of the electrode connection area obtained by the picosecond green laser film surface etching during the formation of the sub-cell is different. In this example, the width of the electrode connection area is 200μm.

[0070] Comparative Example 1

[0071] This comparative example uses a laser scribing interconnect process to fabricate a flexible perovskite thin-film solar cell module with dimensions of 1200*600mm and 93 sub-cells. The fabrication steps are as follows:

[0072] 1) An ITO layer is deposited on a full-size flexible PET substrate to form the first electrode layer;

[0073] 2) The first electrode layer is divided into 93 regions along its long side using infrared laser P1 technology;

[0074] 3) The intermediate layer was prepared using a reverse structure process;

[0075] 4) Using the picosecond green laser P2 process, scribing is performed along the parallel side of P1 to the ITO electrode;

[0076] 5) ITO / Cu composite back electrode is deposited by magnetron sputtering;

[0077] 6) Using the picosecond green laser P3 process, scribing along the parallel side of P2 to the perovskite layer, completely severing the back electrode;

[0078] 7) An infrared laser edge-cleaning process is used to remove 10mm of the full-size edge for edge sealing;

[0079] 8) Lay the runoff and diversion strips;

[0080] 9) Lay the POE film;

[0081] 10) Lay butyl rubber strips along the edges;

[0082] 11) The flexible PET barrier front panel and back panel are laminated together to obtain a flexible perovskite module.

[0083] In summary, the solar cell module interconnection structures of Examples 2 and 3 and the comparative example were tested using an IV tester under simulated solar light source conditions with standard illumination power to determine the cell photoelectric conversion efficiency and related electrical performance parameters. Specific test results are shown in Table 1.

[0084] Table 1

[0085] Serial Number Open circuit voltage (unit: V) Short-circuit current (unit: A) Fill factor (unit: %) Output power (unit: Wp) Conversion efficiency (unit: %) Example 2 13.3 13.05 75.2 130.5 18.13% Example 3 13.2 12.85 74.8 126.9 17.62% Comparative Example 102.8 1.55 71.4 113.8 15.80%

[0086] Based on the results in Table 1, it can be seen that the shingled modules formed using this interconnection structure can achieve greater power generation with the same module area. Moreover, compared with products using laser-etched interconnection technology, it has the following main technical advantages:

[0087] 1) Larger interconnect contact area for better ohmic contact, improving collection efficiency and significantly increasing fill factor.

[0088] 2) A larger effective area can be obtained with the same size module, which directly increases the photocurrent of the module, thereby greatly improving the module efficiency.

[0089] 3) The battery current can be significantly increased. Due to the smaller interconnect resistance, the power loss is smaller, which can fully match the output characteristics of the current mainstream crystalline silicon modules and significantly reduce the system cost of thin-film photovoltaic module installation.

[0090] 4) Compared to non-shingled connections, it can also achieve larger photocurrent and higher fill factor, thus achieving higher module efficiency.

[0091] The present invention has been described in detail above, with the aim of enabling those skilled in the art to understand and implement the invention. However, this description should not be construed as limiting the scope of protection of the invention. All equivalent changes or modifications made in accordance with the spirit and essence of the invention should be included within the scope of protection of the invention.

Claims

1. A flexible thin-film solar cell shingle interconnection structure comprising a plurality of sub-cells, each sub-cell comprising a substrate layer, a first electrode layer, a device layer, a second electrode layer, and a busbar layer, opposite sides of each sub-cell forming a first interconnection portion and a second interconnection portion, respectively, characterized in that, The substrate layer, the first electrode layer, the device layer, the second electrode layer and the busbar layer of each sub-cell are aligned at the interconnection side to form a first interconnection part; the interconnection side of the second electrode layer, the device layer, the first electrode layer and the substrate layer is formed from the top to the bottom in an epitaxial manner based on the interconnection side of the busbar layer as a reference, and the interconnection side of the first electrode layer and the substrate layer is bent downward and inward to form a bent and folded part adhered to the bottom of the substrate layer, and the second interconnection part is formed between the side of the reference, the interconnection side and the bent and folded part, the sub-cell further comprises an interconnection connecting layer covering the entire surface of the first electrode layer of the bent and folded part, and the interconnection connecting layer is insulated and separated from the busbar layer, each sub-cell is raised upward from the second interconnection part, and the interconnection connecting layer extended inward from the bottom of the second interconnection part of the previous sub-cell is connected to the top of the busbar layer of the first interconnection part of the next sub-cell to form a cell string in a downward and upward tile-like interconnection.

2. The flexible thin-film solar cell shingled interconnection structure of claim 1, wherein, The epitaxial side of the second electrode layer is aligned with the epitaxial side of the device layer; and / or, the first electrode layer, the substrate layer and the interconnection connecting layer are aligned from the inward extension side of the bent and folded part.

3. The flexible thin-film solar cell shingled interconnection structure of claim 1, wherein, The inward extension width of the bent and folded part is greater than the width of the interconnection side of the second electrode layer.

4. The flexible thin-film solar cell shingled interconnection structure of claim 1, wherein, The busbar layer comprises a covering segment located at the interconnection side and covering the corresponding side of the second electrode layer, and a plurality of busbar strips distributed side by side on the second electrode layer and in communication with the covering segment, wherein the ends of the plurality of busbar strips away from the covering segment are aligned, and the aligned end surface constitutes the side of the reference, and the epitaxial width formed by the second electrode layer is the insulation width between the interconnection connecting layer and the busbar layer.

5. The flexible thin-film solar cell shingled interconnection structure of claim 4, wherein, The width of the covering segment is greater than or equal to the inward extension width of the bent and folded part.

6. The flexible thin-film solar cell shingling interconnection structure of claim 1, wherein, The inclination angles of each sub-cell are the same, and the interconnection connecting layer at the bottom of the bent and folded part is connected to the top of the interconnection side of the busbar layer of the first interconnection part in the downward and upward tile-like interconnection based on the conductive adhesive.

7. A process for preparing a flexible thin-film solar cell shingle interconnection structure as claimed in any one of claims 1 to 6, characterized in that, It comprises the following steps: S1, preparation of sub-cell Firstly, a flexible substrate is selected as the substrate layer, and a first electrode layer, a device layer and a second electrode layer are formed on the surface of the substrate layer in sequence; secondly, the opposite sides of the obtained structure layer are taken as the interconnection sides, and the film layer on the upper part of the first electrode layer is removed by edge cutting based on one interconnection side as a reference to form the interconnection side of the first electrode layer and the substrate layer in an epitaxial manner; then, the interconnection connecting layer is deposited on the interconnection side of the first electrode layer to form a busbar layer on the second electrode layer, wherein the cut side of the second electrode layer and the device layer forms the interconnection side in an epitaxial manner relative to the busbar layer, the interconnection connecting layer and the busbar layer are insulated and separated in a staggered manner, and the uncut substrate layer, the first electrode layer, the device layer, the second electrode layer and the busbar layer are aligned at the interconnection side to form a first interconnection part; finally, the first electrode layer, the substrate layer and the interconnection connecting layer are bent downward and inward simultaneously based on the corresponding interconnection side to form a bent and folded part adhered to the substrate layer, wherein the bent and folded part, the interconnection side of the device layer and the second electrode layer, and the interval side of the busbar layer form a second interconnection part; S2, tile interconnection The sub-cell in step S1 is raised upward from the second interconnection part, and the interconnection connecting layer extended inward from the bottom of the second interconnection part of the previous sub-cell is connected to the top of the busbar layer of the first interconnection part of the next sub-cell to form a cell string in a downward and upward tile-like interconnection.

8. The process for preparing a flexible thin film solar cell shingled interconnection structure according to claim 7, wherein In step S1, the structure layer is a single body or is cut into several sub-bodies based on a full-size battery, and then the first interconnection part and the second interconnection part are formed for each sub-body.

9. The process for preparing a flexible thin film solar cell shingled interconnection structure of claim 7, wherein, In step S1, the material of the flexible substrate is ultra-thin flexible glass or polymer, and the polymer is any one or more of polyethylene terephthalate, polyethylene naphthalate, polyimide, poly-p-xylylene, and polycarbonate; if the surface of the substrate layer formed by the flexible substrate is the light-receiving surface of the battery, the first electrode layer is a transparent conductive oxide; if the surface of the substrate layer is not the light-receiving surface of the battery, the first electrode layer is a transparent conductive oxide, a metal, or a composite stack of a metal and a transparent conductive oxide.

10. The process for preparing a flexible thin film solar cell shingled interconnection structure of claim 9, wherein: The transparent conductive oxide includes fluorine-doped tin oxide, tin-doped indium oxide, zinc-doped indium oxide, aluminum-doped zinc oxide, tungsten-doped indium oxide, titanium-doped tin indium oxide, boron-doped zinc oxide, and cerium-doped indium oxide, and the transparent conductive oxide is any one or more of the included materials; and / or, the metal includes copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, and manganese, and the metal is one or more of the included materials.

11. The process for preparing a flexible thin film solar cell shingled interconnection structure of claim 7, wherein: In step S1, the deposition method of the first electrode layer includes vacuum evaporation, magnetron sputtering, reactive plasma deposition, chemical vapor deposition, screen printing, electroplating, and transfer printing, and the deposition method is any one of the included methods; and the thickness of the formed first electrode layer is 10-1000 nm.

12. The process for preparing a flexible thin film solar cell shingled interconnection structure of claim 7, wherein: In step S1, the material of the device layer is amorphous silicon germanium, copper indium gallium selenide, cadmium telluride, gallium arsenide, or perovskite; and / or, the deposition method of the device layer includes vacuum evaporation, magnetron sputtering, reactive plasma deposition, chemical vapor deposition, screen printing, electroplating, coating, spraying, printing, near-space sublimation deposition, and gas-phase transport deposition, and the deposition method is any one of the included methods.

13. The process for preparing a flexible thin film solar cell shingled interconnection structure of claim 7, wherein: In step S1, the cutting method is laser and / or mechanical scribing, and the upper film layer is removed based on the surface of the first electrode layer to form a corresponding interconnection side edge, wherein the first electrode layer and the substrate layer are aligned, and the width of the corresponding interconnection side edge is at least 50 μm, and the interconnection connection layer fully covers the corresponding interconnection side edge; and / or, the second electrode layer and the device layer interconnection side are aligned, and the width of the formed interconnection side edge is at least 50 μm.

14. The process for preparing a flexible thin film solar cell shingled interconnection structure of claim 7, wherein: Both the busbar layer and the interconnection connection layer are metalized pattern layers, wherein the metalized pattern layer includes a grid line layer and / or a cover plate layer, and the material used by the metalized pattern layer includes copper, silver, iron, aluminum, tungsten, molybdenum, chromium, nickel, tantalum, vanadium, titanium, and manganese, and the material used by the metalized pattern layer is one or more of the included materials.

15. A flexible thin film solar cell shingle assembly, characterized by, It includes a battery string and a current lead strip made by the flexible thin-film solar cell tile interconnection structure preparation process of any one of claims 7 to 14, wherein the battery string has a plurality of gaps between each adjacent two battery strings, and the width of the gap is ≥50 μm, and the current lead strip respectively communicates the first interconnection part and the second interconnection part of the plurality of battery strings on the same side, and the communication method is parallel or series.

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