CZTSSe solar cell string and solar cell module comprising same

Abstract

The utility model provides a CZTSSe solar cell string with a series connection structure and a CZTSSe solar cell module. The CZTSSe solar cell string comprises at least two CZTSSe solar sub-cells which are connected in series, and each CZTSSe solar sub-cell comprises a bottom electrode, a CZTSSe light absorption layer, a buffer layer, a transparent conductive layer and a top electrode which are sequentially stacked from bottom to top. The bottom electrode has a double-sided conductive structure. Every two adjacent CZTSSe solar sub-cells are connected in series through a flexible solid-state conductive adhesive connecting layer, and the two opposite surfaces of each flexible solid-state conductive adhesive connecting layer are connected with the bottom electrode of the previous CZTSSe solar sub-cell and the top electrode of the next CZTSSe solar sub-cell respectively. And the flexible solid conductive adhesive connecting layer is used as a conductive material between the sub-cells, so that the high-efficiency low-cost large-area flexible photovoltaic module is realized.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of copper zinc tin sulfur selenium solar cell module, in particular to a kind of CZTSSe solar cell string with series structure and the CZTSSe solar cell module comprising the CZTSSe solar cell string of this. BACKGROUND

[0002] With the high-speed development of human society, people's demand for energy increases day by day. However, the current global energy structure is still dominated by high-pollution and high-carbon emission fossil energy, leading to global warming and abnormal climate in recent years. Therefore, developing clean energy has become the only way. Solar cells can directly convert solar energy into electricity, which is an ideal form of energy utilization. Copper zinc tin sulfur selenium (Cu2ZnSn(S, Se)4, abbreviated as CZTSSe) solar cell, as a new type of thin film solar cell, has the advantages of low preparation cost, high abundance of constituent elements on earth and high process compatibility, and has attracted more and more attention. After the development of the last twenty years, the highest power conversion efficiency (PCE) of CZTSSe solar cell has reached nearly 15%, showing the potential for industrialization.

[0003] However, most of the current CZTSSe solar cell technologies are based on small-area devices, which cannot adapt to large-scale module production. The module technology widely used in the field of thin film solar cells is laser scribing technology. Such module technology requires single large-area thin film to have very high uniformity. In addition, since the CZTSSe thin film thickness reaches microns, there will be obvious thermal effects in the laser etching process, which requires very high precision for laser etching, which will also greatly increase the cost of equipment and process repeatability. Therefore, it is crucial to develop a photovoltaic module technology more suitable for CZTSSe solar cells. UTILITY MODEL CONTENTS

[0004] In view of the above problems, the utility model provides a CZTSSe solar cell string with series structure and a CZTSSe solar cell module comprising the CZTSSe solar cell string, which overcomes the above problems or at least partially solves the above problems.

[0005] One object of the utility model is to provide a CZTSSe solar cell string and a CZTSSe solar cell module with high preparation efficiency.

[0006] Another object of the utility model is to reduce the uniformity requirement of the module for large-area thin film and increase the yield.

[0007] Another purpose of the utility model lies in greatly reducing the weight of photovoltaic module.

[0008] Still another purpose of the utility model lies in realizing flexible and bendable solar cell.

[0009] In particular, according to one aspect of the utility model, a CZTSSe solar cell string with series structure is provided, which comprises at least two CZTSSe solar sub-cells connected in series, each of the CZTSSe solar sub-cells comprises, from bottom to top, a bottom electrode, a CZTSSe light absorption layer, a buffer layer, a transparent conductive layer and a top electrode; wherein the bottom electrode has a double-sided conductive structure; each two adjacent CZTSSe solar sub-cells are connected in series through a flexible solid-state conductive adhesive connecting layer, and the opposite two surfaces of the flexible solid-state conductive adhesive connecting layer are connected with the bottom electrode of the previous CZTSSe solar sub-cell and the top electrode of the next CZTSSe solar sub-cell respectively.

[0010] Optionally, the flexible solid-state conductive adhesive connecting layer is in strip shape, comprising a flexible conductive strip and two conductive adhesive layers respectively coated on the two surfaces of the flexible conductive strip, and the two conductive adhesive layers are connected with the bottom electrode of the previous CZTSSe solar sub-cell and the top electrode of the next CZTSSe solar sub-cell respectively.

[0011] Optionally, the thickness of the flexible conductive strip is less than 100 μm.

[0012] Optionally, the thickness of each conductive adhesive layer is less than 100 μm.

[0013] Optionally, the bottom electrode is a double-sided conductive metal foil substrate.

[0014] The thickness of the metal foil is 10-200 μm.

[0015] Optionally, the at least two CZTSSe solar sub-cells are arranged in a shingle pattern.

[0016] According to another aspect of the utility model, a CZTSSe solar cell module is also provided, which comprises, from top to bottom, a first encapsulating film, a first encapsulating adhesive, a CZTSSe solar cell module, a second encapsulating adhesive and a second encapsulating film; wherein

[0017] The CZTSSe solar cell module is composed of a single aforementioned CZTSSe solar cell string; or

[0018] The CZTSSe solar cell module is composed of at least two aforementioned CZTSSe solar cell strings connected in parallel.

[0019] Optionally, each of the CZTSSe solar cell strings is provided with a first wire extending outward from the top electrode of the CZTSSe solar sub-cell at the head end of the string and a second wire extending outward from the bottom electrode of the CZTSSe solar sub-cell at the tail end of the string.

[0020] In the case where the CZTSSe solar cell module is formed by connecting at least two of the CZTSSe solar cell strings in parallel, the parallel connection is achieved by welding the first wires of each two adjacent CZTSSe solar cell strings together and welding the second wires of each two adjacent CZTSSe solar cell strings together.

[0021] Optionally,

[0022] The first wire and the second wire are double-sided conductive metal strips or metal wires.

[0023] Optionally, the first encapsulation film is a transparent organic encapsulation layer.

[0024] The second encapsulation film is an organic encapsulation layer.

[0025] In the CZTSSe solar cell string and the CZTSSe solar module provided by the utility model, at least two CZTSSe solar sub-cells are connected in series to form a CZTSSe solar cell string, and the adjacent CZTSSe solar sub-cells are connected in series through a flexible solid-state conductive adhesive connecting layer. Compared with the traditional thermosetting conductive adhesive, the use of the flexible solid-state conductive adhesive connecting layer as the conductive material between the sub-cells can greatly reduce the difficulty of cell series connection and shorten the silver adhesive curing period, and can also avoid the damage of the high-temperature annealing process to the CZTSSe solar cell, thereby greatly improving the preparation efficiency. Moreover, the use of the flexible solid-state conductive adhesive connecting layer can also be beneficial to the realization of the splicable flexible photovoltaic module.

[0026] Further, the flexible solid-state conductive adhesive connecting layer comprises a flexible conductive strip and two conductive adhesive layers respectively coated on the two surfaces of the flexible conductive strip. By using low-cost flexible conductive strip materials and conductive adhesive layer materials, the cost of the cell string and the module can be reduced.

[0027] Further, the bottom electrode of each CZTSSe solar sub-cell is a double-sided conductive metal foil substrate. Compared with the traditional glass substrate, the use of the metal foil substrate can greatly reduce the weight of the photovoltaic module.

[0028] Further, by adopting the flexible solid-state conductive adhesive connecting layer to connect at least two CZTSSe solar sub-cells in series to form a CZTSSe solar cell string, and further connecting at least two CZTSSe solar cell strings in parallel to form a CZTSSe solar cell module, and finally forming a CZTSSe solar cell assembly, the uniformity requirement of the assembly on a large-area thin film is reduced, and the yield is increased.

[0029] Further, the structure of connecting the CZTSSe solar sub-cells in series through the flexible solid-state conductive adhesive connecting layer and the structure of connecting the CZTSSe solar cell strings in parallel through wire welding realize the flexible and bendable solar cell.

[0030] The above description is only a summary of the technical scheme of the present application, in order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented according to the content of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described.

[0031] According to the detailed description of the specific embodiments of the present application in the following text combined with the drawings, those skilled in the art will understand the above and other purposes, advantages and features of the present application more clearly. BRIEF DESCRIPTION OF DRAWINGS

[0032] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those skilled in the art. The drawings are only for the purpose of illustrating the preferred embodiments and are not considered as limiting the present application. Moreover, the same reference numerals are used to represent the same parts throughout the drawings. In the drawings:

[0033] Figure 1 is a structural schematic view of a CZTSSe solar cell string with a series structure according to an embodiment of the present application;

[0034] Figure 2 is a structural schematic view of a flexible solid-state conductive adhesive connecting layer according to an embodiment of the present application;

[0035] Figure 3 is a structural schematic view of a CZTSSe solar cell assembly according to an embodiment of the present application;

[0036] Figure 4 is a structural schematic view of a CZTSSe solar cell module in a CZTSSe solar cell assembly according to an embodiment of the present application. DETAILED DESCRIPTION

[0037] Exemplary embodiments of the present disclosure will be described in greater detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly understood, and so that the scope of the present disclosure can be conveyed to those skilled in the art.

[0038] In view of the foregoing problems, the utility model provides a kind of CZTSSe solar cell string 100 with series structure.

[0039] Figure 1 For the structural schematic diagram of the structural schematic diagram of the CZTSSe solar cell string 100 with series structure according to an embodiment of the utility model.

[0040] Referring to Figure 1 As shown in the drawings, in one embodiment, the CZTSSe solar cell string 100 of the utility model includes at least two CZTSSe solar sub-cells 110 connected in series. Each CZTSSe solar sub-cell 110 includes, from bottom to top, a bottom electrode 111, a CZTSSe light absorption layer 112, a buffer layer 113, a transparent conductive layer 114 (also referred to as a window layer), and a top electrode 115. The bottom electrode 111 has a double-sided conductive structure. Each two adjacent CZTSSe solar sub-cells 110 are connected in series by a flexible solid-state conductive adhesive connecting layer 116. Specifically, the opposite surfaces of the flexible solid-state conductive adhesive connecting layer 116 are connected to the bottom electrode 111 of the previous CZTSSe solar sub-cell 110 and the top electrode 115 of the subsequent CZTSSe solar sub-cell 110, respectively, thereby connecting the two CZTSSe solar sub-cells 110 in series.

[0041] In the CZTSSe solar cell string 100 provided by the embodiment of the utility model, at least two CZTSSe solar sub-cells 110 are connected in series to form the CZTSSe solar cell string 100, and the adjacent CZTSSe solar sub-cells 110 are connected in series by the flexible solid-state conductive adhesive connecting layer 116. Compared with the traditional thermosetting conductive adhesive, using the flexible solid-state conductive adhesive connecting layer 116 as the conductive material between the sub-cells can greatly reduce the difficulty of connecting the cells in series and shorten the silver adhesive curing period, and can also avoid the damage to the CZTSSe solar cell caused by the high-temperature annealing process, thereby greatly improving the preparation efficiency. Moreover, the use of the flexible solid-state conductive adhesive connecting layer 116 can also facilitate the realization of a splicable flexible photovoltaic module.

[0042] In some embodiments, the flexible solid-state conductive adhesive connecting layer 116 is in the form of a strip, so as to more conveniently fit the bottom electrode 111 and the top electrode 115 of the CZTSSe solar sub-cell 110.

[0043] Figure 2 This is a schematic diagram of the structure of the flexible solid conductive adhesive bonding layer 116 according to an embodiment of the present invention. Figure 2 As shown, in some embodiments, the flexible solid conductive adhesive connecting layer 116 includes a flexible conductive strip 1161 and two conductive adhesive layers 1162 respectively coated on the two surfaces of the flexible conductive strip 1161. That is, the flexible solid conductive adhesive connecting layer 116 has a conductive adhesive / flexible conductive strip / conductive adhesive structure. The two conductive adhesive layers 1162 are respectively connected to the bottom electrode 111 of the preceding CZTSSe solar sub-cell 110 and the top electrode 115 of the following CZTSSe solar sub-cell 110, thereby realizing convenient series connection of CZTSSe solar sub-cells 110 while achieving flexible series connection with low electrical loss between sub-cells.

[0044] In some embodiments, the thickness of the flexible conductive strip 1161 is less than 100 μm, for example, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, or 10 μm.

[0045] In some embodiments, the material of the flexible conductive strip 1161 may be Cu, Ag, Al or graphite, thereby better balancing conductivity and flexibility.

[0046] In some embodiments, the conductive adhesive layer 1162 may be made of an adhesive mixed with conductive nanoparticles. The adhesive may include at least one selected from epoxy resins, silicone rubbers, acrylates, etc. The conductive nanoparticles may include at least one selected from silver nanoparticles, aluminum nanoparticles, copper nanoparticles, etc.

[0047] Specifically, the materials of the conductive adhesive layer 1162 include, but are not limited to, epoxy resin adhesive mixed with silver nanoparticles, epoxy resin adhesive mixed with aluminum nanoparticles, silicone adhesive mixed with silver nanoparticles, and acrylate mixed with copper nanoparticles.

[0048] By using low-cost flexible conductive strip 1161 material and conductive adhesive layer 1162 material, the cost of battery strings and modules can be reduced.

[0049] In some embodiments, the thickness of each conductive adhesive layer 1162 may be less than 100 μm, for example, 90 μm, 80 μm, 70 μm, 60 μm, 50 μm, 40 μm, 30 μm, 20 μm, or 10 μm. This ensures the flexibility of the entire flexible solid conductive adhesive bonding layer 116.

[0050] In some embodiments, the bottom electrode 111 is a double-sided conductive metal foil substrate. Compared with conventional glass substrates, the use of metal foil substrates can significantly reduce the weight of photovoltaic modules.

[0051] In some embodiments, the metal foil can be molybdenum foil, titanium foil, or stainless steel foil sputtered with molybdenum, etc.

[0052] In some embodiments, the thickness of the metal foil is 10-200 μm, such as 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, etc.

[0053] Preferably, the thickness of the metal foil is 50-100 μm.

[0054] In some embodiments, the thickness of the CZTSSe light absorption layer 112 is 0.5-5 μm, such as 1 μm, 2 μm, 3 μm, 4 μm, etc.

[0055] In some alternative embodiments, the precursor of the CZTSSe light absorption layer 112 can be prepared by solution method, sputtering method, multi-step co-evaporation method, electrochemical deposition method, etc. The CZTSSe light absorption layer 112 can be prepared by post-selenization method, co-evaporation method (such as multi-step co-evaporation method), or single crystal method.

[0056] In some embodiments, the material of the buffer layer 113 can include, but is not limited to, cadmium sulfide (CdS), zinc oxygen sulfide (Zn(O,S)), zinc tin oxide (ZnSnO3), zinc cadmium sulfide (ZnCdS), etc. x Cd 1-x S).

[0057] In some embodiments, the thickness of the buffer layer 113 is 10-100 nm, such as 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm.

[0058] In some alternative embodiments, the buffer layer 113 can be prepared by chemical water bath deposition method, magnetron sputtering method, thermal evaporation method, or atomic layer deposition method.

[0059] In some embodiments, the transparent conductive layer 114 can adopt a double-layer structure (not shown in the figure) including a high-resistance anti-leakage layer connected with the buffer layer 113 and a low-resistance conductive transmission layer connected with the top electrode 115.

[0060] Alternatively, the transparent conductive layer 114 can be prepared by magnetron sputtering method.

[0061] In some embodiments, the material of the high-resistance anti-leakage layer includes, but is not limited to, zinc oxide (ZnO), zinc magnesium oxide (Zn x Mg 1-x O), tin oxide (SnO2), etc. The thickness of the high-resistance anti-leakage layer is 5-100 nm, such as 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm.

[0062] In some embodiments, the low-resistance conductive transport layer can be an aluminum-doped zinc oxide (AZO) layer, an indium-tin oxide (ITO) layer, or an indium-zinc oxide (IZO) layer. The low-resistance conductive transport layer has a thickness of 50-1500 nm, such as 100 nm, 300 nm, 500 nm, 800 nm, 1000 nm, 1200 nm, 1300 nm, 1400 nm.

[0063] In some embodiments, the material of the top electrode 115 includes, but is not limited to, Ag, Ni / Al, Ni / Cu, Au, etc.

[0064] In some optional embodiments, the top electrode 115 can be prepared by a thermal evaporation deposition method or an electroplating method.

[0065] In a specific embodiment, the top electrode 115 is a Ni / Al electrode, in which the thickness of the Ni layer is 5-100 nm, and the thickness of the Al layer is 0.1-10 μm.

[0066] Continuing to refer to Figure 1 In some embodiments, each CZTSSe solar sub-cell 110 can further include an anti-reflection layer 117 disposed on top of the transparent conductive layer 114.

[0067] The material of the anti-reflection layer 117 can include, but is not limited to, magnesium fluoride (MgF2), lithium fluoride (LiF), silicon dioxide (SiO2), silicon nitride (Si3N4), etc.

[0068] In some embodiments, the at least two CZTSSe solar sub-cells 110 in the solar cell string 100 are arranged in a shingled manner. This arrangement structure facilitates the series connection between the sub-cells while ensuring the maximum light-receiving area of each sub-cell.

[0069] Based on the same technical concept, the utility model further provides a CZTSSe solar cell module 10, which can be prepared based on the aforementioned CZTSSe solar cell string 100.

[0070] Figure 3 FIG. 1 is a structural schematic diagram of a CZTSSe solar cell module 140 in a CZTSSe solar cell assembly 10 according to an embodiment of the utility model. Figure 4 FIG. 1 is a structural schematic diagram of a CZTSSe solar cell module 140 in a CZTSSe solar cell assembly 10 according to an embodiment of the utility model.

[0071] Continuing to refer to Figure 3As shown, the CZTSSe solar cell module 10 generally comprises, from top to bottom, a first encapsulation film 120, a first encapsulation adhesive 130, a CZTSSe solar cell module 140, a second encapsulation adhesive 150, and a second encapsulation film 160.

[0072] The first encapsulation film 120 can be a transparent organic encapsulation layer formed using a transparent organic encapsulation material, to ensure its light transmittance.

[0073] In some embodiments, the material of the first encapsulation film 120 can include, but is not limited to, at least one of polyethylene terephthalate (PET), ethylene-tetrafluoroethylene copolymer (ETFE), polyethylene naphthalate (PEN), polyimide (PI), etc.

[0074] Since the second encapsulation film 160 is located at the back of the solar cell module 10, the second encapsulation film 160 has no specific requirement on the light transmittance of its material, and can be an organic encapsulation layer formed using a general organic encapsulation material.

[0075] In some embodiments, the material of the second encapsulation film 160 can include, but is not limited to, at least one of PET, ETFE, PEN, PI, polyvinylidene fluoride (PVF), etc.

[0076] The first encapsulation adhesive 130 and the second encapsulation adhesive 150 can use the same or different transparent encapsulation materials.

[0077] In some embodiments, the material of the first encapsulation adhesive 130 and the second encapsulation adhesive 150 can include at least one of ethylene-vinyl acetate copolymer (EVA), polyolefin thermoplastic elastomer (POE), EPE (EVA-POE-EVA) three-layer adhesive film, etc.

[0078] In some embodiments, the CZTSSe solar cell module 140 is composed of a single aforementioned CZTSSe solar cell string 100, as shown in FIG. 2. Figure 3

[0079] In other embodiments, the CZTSSe solar cell module 140 is composed of at least two aforementioned CZTSSe solar cell strings 100 in parallel. For example, as shown in FIG. 3, in a specific embodiment, the CZTSSe solar cell module 140 is composed of 3 CZTSSe solar cell strings 100 in parallel. Figure 4

[0080] ​​By adopting the flexible solid-state conductive adhesive connecting layer 116 to connect at least two CZTSSe solar sub-cells 110 in series to form a CZTSSe solar cell string 100, and further connecting at least two CZTSSe solar cell strings 100 in parallel to form a CZTSSe solar cell module 140, a CZTSSe solar cell assembly 10 is finally formed, which reduces the uniformity requirement of the assembly on a large-area thin film and increases the yield.

[0081] Further, each CZTSSe solar cell string 100 is provided with a first wire 170 extending outward from the top electrode 115 of the CZTSSe solar sub-cell 110 at the head end thereof, and a second wire 180 extending outward from the bottom electrode 111 of the CZTSSe solar sub-cell 110 at the tail end thereof.

[0082] In the case where the CZTSSe solar cell module 140 is composed of a single CZTSSe solar cell string 100, the first wire 170 and the second wire 180 directly serve as the lead-out wires of the CZTSSe solar cell assembly 10.

[0083] In the case where the CZTSSe solar cell module 140 is composed of at least two CZTSSe solar cell strings 100 in parallel, the CZTSSe solar cell strings 100 can also be connected in parallel by welding the first wires 170 and the second wires 180 respectively. For example, as shown in Figure 4 each two adjacent CZTSSe solar cell strings 100 are welded together by the first wires 170, and the second wires 180 of the two CZTSSe solar cell strings 100 are also welded together.

[0084] The structure of connecting the CZTSSe solar sub-cells 110 in series by the flexible solid-state conductive adhesive connecting layer 116 and the structure of connecting the CZTSSe solar cell strings 100 in parallel by welding the wires realize the flexible and bendable solar cell.

[0085] The first wire 170 and the second wire 180 can be made of the same or different materials.

[0086] In some embodiments, the first wire 170 and the second wire 180 are double-sided conductive metal strips or metal wires.

[0087] Specifically, the metal strip can be an Ag strip, an Al strip, a Cu strip, a conductive adhesive tape, or a graphite strip, etc.

[0088] The metal wire can be an Ag wire, a Cu wire, or an Al wire, etc.

[0089] The utility model uses low-cost CZTSSe photovoltaic cell materials, which can reduce the cost of raw materials.

[0090] The technical features in the above embodiments can be combined in any manner. To simplify the description, all possible combinations in the above embodiments are not described in detail. However, as long as the combinations of the technical features do not exist contradictions, they should be considered as belonging to the scope of the present specification.

[0091] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some examples, well-known methods, structures and techniques are not shown in detail in order not to obscure the understanding of the present specification.

[0092] So far, those skilled in the art should recognize that although the present application has been shown and described in detail in the above embodiments, many other variations or modifications can be directly determined or deduced according to the disclosure of the present application without departing from the spirit and scope of the present application, which conform to the principles of the present application. Therefore, the scope of the present application should be understood and recognized as covering all these other variations or modifications.

Claims

1. A CZTSSe solar cell string with a series structure, comprising at least two CZTSSe solar sub-cells connected in series, each of the CZTSSe solar sub-cells comprising, from bottom to top, a bottom electrode, a CZTSSe light-absorbing layer, a buffer layer, a transparent conductive layer, and a top electrode stacked sequentially; characterized in that, The bottom electrode has a double-sided conductive structure; each pair of adjacent CZTSSe solar sub-cells are connected in series by a flexible solid conductive adhesive connecting layer, and the two opposite surfaces of the flexible solid conductive adhesive connecting layer are respectively connected to the bottom electrode of the previous CZTSSe solar sub-cell and the top electrode of the next CZTSSe solar sub-cell.

2. The CZTSSe solar cell string according to claim 1, characterized in that, The flexible solid conductive adhesive bonding layer is strip-shaped, including a flexible conductive strip and two conductive adhesive layers respectively coated on two surfaces of the flexible conductive strip. The two conductive adhesive layers are respectively connected to the bottom electrode of the previous CZTSSe solar sub-cell and the top electrode of the next CZTSSe solar sub-cell.

3. The CZTSSe solar cell string according to claim 2, characterized in that, The thickness of the flexible conductive strip is less than 100 μm.

4. The CZTSSe solar cell string according to claim 2, characterized in that, The thickness of each conductive adhesive layer is less than 100 μm.

5. The CZTSSe solar cell string according to claim 1, characterized in that, The bottom electrode is a double-sided conductive metal foil substrate; The thickness of the metal foil is 10–200 μm.

6. The CZTSSe solar cell string according to any one of claims 1-5, characterized in that, The at least two CZTSSe solar sub-cells are arranged in a shingled configuration.

7. A CZTSSe solar cell module, characterized in that, It includes, from top to bottom, a first encapsulation film, a first encapsulating adhesive, a CZTSSe solar cell module, a second encapsulating adhesive, and a second encapsulation film; wherein The CZTSSe solar cell module consists of a single CZTSSe solar cell string according to any one of claims 1-6; or The CZTSSe solar cell module is composed of at least two CZTSSe solar cells connected in series and parallel according to any one of claims 1-6.

8. The CZTSSe solar cell module according to claim 7, characterized in that, Each of the CZTSSe solar cell strings is provided with a first wire extending outward from the top electrode of the CZTSSe solar cell at its first end and a second wire extending outward from the bottom electrode of the CZTSSe solar cell at its last end. In the case where the CZTSSe solar cell module is composed of at least two CZTSSe solar cell strings connected in parallel, the parallel connection is achieved by welding the first wires of every two adjacent CZTSSe solar cell strings together and welding their second wires together.

9. The CZTSSe solar cell module according to claim 8, characterized in that, The first and second conductors are double-sided conductive metal strips or metal wires.

10. The CZTSSe solar cell module according to claim 7, characterized in that, The first encapsulation film is a transparent organic encapsulation layer; The second encapsulation film is an organic encapsulation layer.

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