A flexible perovskite / crystalline silicon tandem solar cell module and its fabrication method

Abstract

This invention provides a method for fabricating a flexible perovskite / crystalline silicon tandem solar cell module, mainly comprising: firstly, fabricating several semi-finished crystalline silicon cells; then, back-mounting them to obtain a bottom flexible crystalline silicon cell module; next, fabricating an intermediate connecting layer and a top layer of semi-finished perovskite cells on the bottom flexible crystalline silicon cell module; etching and cutting from top to bottom to obtain several vertically independent and separated perovskite / crystalline silicon tandem cells; finally, encapsulating the module to obtain the flexible perovskite / crystalline silicon tandem solar cell module. This invention integrates the fabrication processes of the bottom cell, the top cell, and the entire module, simplifying the fabrication process and significantly reducing the production cost of the flexible tandem module, making it suitable for industrialization. Furthermore, this invention also discloses a flexible perovskite / crystalline silicon tandem solar cell module fabricated using the above method.

Description

Technical Field

[0001] This invention belongs to the field of tandem solar cell module technology, specifically relating to a flexible perovskite / crystalline silicon tandem solar cell module and its preparation method. Background Technology

[0002] As research in the field of solar cells continues to deepen, the photoelectric conversion efficiency of single-junction solar cells (such as crystalline silicon cells, and thin-film cells made of cadmium telluride, copper indium gallium selenide, and perovskite) is constantly improving and approaching the Shockley-Queisser theoretical limit. By designing tandem solar cell structures using materials with different optical bandgap widths, the wavelength range of solar spectrum absorption and utilization by the cells can be comprehensively broadened, thereby enabling the cell efficiency to break through the Shockley-Queisser theoretical limit. In recent years, with the rapid development of the perovskite solar cell industry, crystalline silicon and perovskite have become the two most cost-effective materials for achieving high efficiency in single-junction cells, and the theoretical efficiency of tandem cells composed of these two materials can exceed 45%. Therefore, perovskite / crystalline silicon cells are the most promising technology route for next-generation industrialized photovoltaic cells. However, the current fabrication process of perovskite / crystalline silicon tandem cells is still relatively complex and costly, failing to meet the production cost requirements for industrialization. Further simplification of the fabrication process is needed to reduce its cost.

[0003] Flexible solar cells are solar cells fabricated on flexible material substrates. Their characteristics include bendability, foldability, lightweight applications, and wide range of uses. However, existing flexible solar cells are mainly single-junction cells, such as copper indium gallium selenide (CIGS) solar cells, perovskite solar cells, and organic solar cells, whose photoelectric conversion efficiency is not high enough, limiting their further applications. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a flexible perovskite / crystalline silicon tandem solar cell module and its fabrication method. The top layer of the flexible perovskite / crystalline silicon tandem solar cell module (hereinafter referred to as "flexible perovskite / crystalline silicon tandem cell module" or "flexible tandem module") has an optical bandgap (E) of [insert value here]. g The perovskite solar cell with a relatively wide bandgap primarily utilizes high-energy (short wavelength) and medium-energy (medium wavelength) photons from the solar spectrum; the underlying layer is a crystalline silicon solar cell with a narrower bandgap (E... g =1.12eV), primarily utilizing photons in the low-to-medium energy range of the solar spectrum, including the medium and long wavelengths. This allows for more comprehensive and efficient utilization of photons across the short, medium, and long wavelength ranges of the solar spectrum, enabling the cell efficiency to exceed the Shockley-Queisser theoretical limit and resulting in higher module power generation. The tandem solar module is a flexible solar cell, expanding the application scenarios for high-efficiency tandem solar cells.

[0005] The fabrication process of the flexible perovskite / crystalline silicon tandem solar cell module disclosed in this invention flexibly integrates the fabrication processes of crystalline silicon cells, perovskite cells, and modules, as summarized below: ① First, a semi-finished crystalline silicon cell (also called a "bottom-layer crystalline silicon sub-cell") is prepared; then, the periphery of the semi-finished crystalline silicon cell is laser-edged to make the periphery electrically insulating; then, combined with the fabrication process of crystalline silicon modules, the back side of the semi-finished crystalline silicon cell is encapsulated, including the preparation of electrode leads and a flexible back substrate layer, thereby forming a "bottom-layer flexible crystalline silicon cell module" composed of several semi-finished crystalline silicon cells. It is understood that the periphery of the cell in this invention includes a ring around the front edge, a ring around the back edge, and each sidewall. ② Based on the prepared bottom-layer flexible crystalline silicon cell module, a large-area intermediate connecting layer and a top-layer semi-finished perovskite cell (also called a "top-layer perovskite sub-cell") are prepared, the area of ​​which can completely cover the bottom-layer flexible crystalline silicon cell module. ③ The large-area top-layer semi-finished perovskite solar cell and intermediate connecting layer are etched and cut to form individual, separate small-area perovskite / crystalline silicon tandem solar cells in the vertical direction. ④ Finally, the tandem solar cells are interconnected and packaged to complete the fabrication of the flexible perovskite / crystalline silicon tandem solar cell module.

[0006] It is understood that the semi-finished crystalline silicon solar cell described in this invention refers to a crystalline silicon solar cell without a front surface (i.e., front electrode) fabricated. In other words, except for the front electrode, the basic structure of the crystalline silicon solar cell, such as the charge transport layer and the back surface (i.e., back electrode), is complete. Similarly, the back electrode of the semi-finished perovskite solar cell described in this invention is not fabricated.

[0007] The flexible perovskite / crystalline silicon tandem solar cell module provided by this invention is a series-connected type, which can be a 2-terminal (2T) series-connected type or a 3-terminal (3T) series-connected type. For the 2T series-connected tandem solar cell, the bottom semi-finished crystalline silicon cell only needs to export one of the photogenerated carriers, electrons and holes, while the other photogenerated carrier is exported from the top semi-finished perovskite cell. For the 3T series-connected tandem solar cell, the bottom semi-finished crystalline silicon cell needs to export both electrons and holes simultaneously, and the top semi-finished perovskite cell will also export one of the electrons and holes simultaneously.

[0008] Understandably, perovskite solar cells can be fabricated at significantly lower temperatures compared to crystalline silicon solar cells. Therefore, the fabrication of perovskite / crystalline silicon tandem solar cells typically begins with the fabrication of the bottom semi-finished crystalline silicon cell. Thus, for tandem flexible perovskite / crystalline silicon tandem solar cell modules, the polarity of the front and back surfaces of the top semi-finished perovskite cell (i.e., whether the photogenerated carriers drawn from the front and back surfaces are electrons or holes) needs to be determined based on the polarity of the front and back surfaces of the bottom semi-finished crystalline silicon cell, thereby forming a tandem solar cell.

[0009] Understandably, the fabrication process and corresponding material selection for the intermediate interconnect layer and the top layer semi-finished perovskite solar cell should be chosen and determined based on the materials of the already fabricated bottom flexible crystalline silicon solar cell module. Specifically, it is essential not to affect or damage any part of the already fabricated bottom flexible crystalline silicon solar cell module, primarily including the bottom semi-finished crystalline silicon solar cell, the metallized interconnect material, and the flexible back-side encapsulation material. The fabrication processes here include high-temperature heat treatment, physical bombardment and chemical reactions of vacuum-phase deposited thin films, wet chemistry, laser or plasma dry etching, etc. Based on meeting this general principle, the material selection and fabrication process for the intermediate interconnect layer and the top layer semi-finished perovskite solar cell are not limited.

[0010] The flexible tandem perovskite / crystalline silicon tandem solar cell module and corresponding fabrication method disclosed in this application are suitable not only for modules consisting of two sub-cells connected in series, but also for modules consisting of three or more sub-cells connected in series. For the latter, the bottom sub-cell uses a crystalline silicon cell, and the top two sub-cells use perovskite cells. It should be noted that an intermediate connecting layer is provided between adjacent perovskite cells. In terms of design, the Eabsorber of each sub-cell... g A well-designed system is needed to make more comprehensive and efficient use of photons in the short, medium, and long wavelength ranges of the solar spectrum.

[0011] The bottom cell of the flexible perovskite / crystalline silicon tandem solar cell module uses a crystalline silicon cell with a bandgap of 1.12 eV, primarily utilizing photons in the low-to-medium energy and long-wavelength bands of the solar spectrum. The silicon substrate can be monocrystalline or polycrystalline silicon, and the substrate doping type can be n-type (phosphorus-doped) or p-type (boron-doped or gallium-doped).

[0012] The specific structure of crystalline silicon solar cells is not limited, but it must be selected based on the overall terminal design of the tandem cell. For 2T series configurations, all-aluminum back surface field (SPF) cells, PERC (passivated emitter and rear cell) cells, passivated contact TOPCon (tunnel oxide and passivated contact) cells, silicon heterojunction (HJT) cells, etc., can be used, and they are not limited to these. For 3T series configurations, interdigitated back contact (IBC) cells, as well as MWT (Metal Wrap Through) or EWT (Emitter Wrap Through) cells, can be used.

[0013] The area and size of crystalline silicon solar cells are not limited. They can adopt the currently popular industrial side lengths of 156mm, 182mm, or 210mm, or these areas can be cut into smaller areas (depending on the application scenario), such as half a cell, one-third of a cell, ..., nth of a cell, etc. It should be emphasized that, since tandem modules need to be fabricated to be flexible, it is better to use smaller crystalline silicon solar cells here.

[0014] The fabrication process of the bottom-layer flexible crystalline silicon solar cell module mainly includes the following steps: ① Fabricating the charge (electron or hole) transport layer of the semi-finished crystalline silicon solar cell; ② The front surface of the semi-finished crystalline silicon solar cell does not need to be metallized, but the back surface needs to be metallized, meaning that only the back electrode of the semi-finished crystalline silicon solar cell needs to be fabricated; ③ Back-side encapsulating several semi-finished crystalline silicon solar cells, including fabricating the back electrode leads and the back flexible substrate layer.

[0015] It is important to note that in this application, the metallized interconnect material, i.e., the electrode leads, on the back of the bottom crystalline silicon cell module must be able to avoid oxidation during the subsequent fabrication of the intermediate interconnect layer and the top semi-finished perovskite cell, thereby ensuring the interconnect performance of the perovskite / crystalline silicon tandem cell module. Here, metal alloys with high conductivity and high-temperature oxidation resistance can be used, such as copper-chromium alloys, copper-chromium-zirconium alloys, copper-chromium-tellurium alloys, nickel-copper-silicon alloys, copper-nickel-chromium alloys, or nickel-chromium-iron alloys, copper-platinum alloys, etc. These alloys, which have good conductivity, also possess excellent high-temperature oxidation resistance.

[0016] Prepare the semi-finished crystalline silicon cells and, in conjunction with the manufacturing process of crystalline silicon modules, fabricate electrode leads and a flexible substrate layer on the back of the semi-finished crystalline silicon cells, i.e., back encapsulation. This forms the "bottom flexible crystalline silicon cell module" of the stacked cell module.

[0017] It is important to note that in this invention, the bottom flexible crystalline silicon cell module has two encapsulation layers. The first flexible encapsulation layer, also known as the "back flexible substrate layer," is formed after the back crystalline silicon semi-finished cell is manufactured. The back flexible substrate layer not only needs to possess good optical performance but also good reliability, including mechanical load performance, anti-degradation and anti-aging properties, UV resistance, and waterproof and moisture-proof performance. The back flexible substrate layer can be made of polymers, metals and alloys, flexible glass, etc. Specifically: organic polymers can be, for example, polyethylene terephthalate (PET), polyimide (PI), polyethylene naphthalate (PEN), polyvinyl alcohol (PVA), etc.; flexible metal or alloy substrates include stainless steel, metal foil, etc.; flexible glass can be a flexible glass substrate suitable for solar photovoltaics. Since the fabrication of the tandem cell module of this invention includes the bottom semi-finished crystalline silicon cell, the preparation of the intermediate connecting layer, the preparation of the top semi-finished perovskite cell, and module encapsulation, materials with good high-temperature resistance are preferentially selected for the back flexible substrate layer. Among the aforementioned flexible substrate materials, the maximum applicable temperature for flexible coated glass is 600℃, for PI (polyimide) it is 300℃, for polyethylene naphthalate (PEN) it is 180℃, for stainless steel it is 1000℃, and so on.

[0018] A certain number and pattern of vias need to be etched into the flexible substrate layer on the back side. These vias are divided into two categories based on their purpose: The first type is electrode lead vias, whose pattern is distributed within the lower vertical edge of the semi-finished crystalline silicon cell. The specific pattern distribution can be designed based on the electrode distribution on the back of the semi-finished crystalline silicon cell. The purpose of these electrode lead vias is to allow the electrode leads on the back of the semi-finished crystalline silicon cell to pass through them. The second type is interconnect vias, which are distributed in the area between two adjacent semi-finished crystalline silicon cells. These are used to interconnect cells of different unit areas in a tandem cell assembly. However, it is important to note that interconnect vias should avoid the centerline and adjacent sides of the area between two adjacent semi-finished crystalline silicon cells as much as possible. This is to prevent damage (etching) of these interconnect vias during the etching and cutting process after the top layer of the tandem cell is fabricated. The diameter range of electrode lead vias and interconnect vias is typically from 0.2 cm to 1 cm. The etching process for these vias can be laser etching, plasma etching, or mechanical etching.

[0019] The flexible back substrate layer secures the bottom semi-finished crystalline silicon cell and the back flexible substrate layer (which has electrode lead vias and interconnect vias) together using encapsulation materials such as crosslinking agents, forming a single unit. In this way, the electrode leads of the bottom flexible crystalline silicon cell module that pass through the back flexible substrate layer are "isolated" from the back flexible substrate layer. The advantage of this design is that it protects the electrode leads of the bottom flexible crystalline silicon cell module from being affected by the subsequent fabrication processes of the intermediate connecting layer and the top semi-finished perovskite cell. The crosslinking agent used here can be a common crosslinking agent for battery module encapsulation, and the encapsulation process can use conventional lamination, with no specific limitations.

[0020] The second flexible encapsulation film on the back, serving as the outermost encapsulation film on the back of the entire perovskite / crystalline silicon tandem solar cell module, is also known as the "back flexible encapsulation layer." This layer requires not only excellent optical performance but also high reliability, including mechanical load resistance, anti-degradation and anti-aging properties, UV resistance, and waterproof and moisture-proof performance. The specific encapsulation material is not limited and can be made from the same material as the back substrate layer. The second flexible encapsulation film is fabricated during the module encapsulation step after the top cell is manufactured, meaning it is produced together with the front encapsulation film.

[0021] The intermediate connecting layer of a perovskite / crystalline silicon tandem solar cell module must be selected in terms of material to ensure good optical and electrical coupling between the bottom crystalline silicon cell and the top perovskite cell, and its fabrication process must not affect or damage the already fabricated bottom flexible crystalline silicon cell module. While meeting these conditions, the specific material and fabrication process of the intermediate connecting layer are not limited. Typically, the material of the intermediate connecting layer can be a transparent conductive oxide, such as tin-doped indium oxide (ITO) or aluminum-doped zinc oxide (AZO), and the fabrication methods can include sputtering, atomic layer deposition (ALD), and rapid plasma deposition.

[0022] The top perovskite cell in a perovskite / crystalline silicon tandem solar module primarily utilizes high-energy (short wavelength) and medium-energy (medium wavelength) photons from the solar spectrum; therefore, the bandgap of the perovskite material must be designed to achieve this. The energy density (E) can be adjusted by modifying the chemical composition of the perovskite thin film. g The typical range is 1.5-2.0 eV, with a more optimized range of 1.6-1.8 eV. Furthermore, the polarity of the perovskite cell electrodes needs to be consistent with that of the underlying crystalline silicon cell to form a series-connected tandem cell module. Based on meeting the above requirements, the specific structure of the perovskite cell is not limited.

[0023] The bottom flexible crystalline silicon solar cell module and the top perovskite solar cell mainly consist of a perovskite absorption layer, an electron transport layer, a hole transport layer, an interface modification layer, an optical antireflection film, and electrodes. The selection of materials and corresponding fabrication processes for each functional layer are not specifically limited in this invention, but are briefly described below:

[0024] The perovskite absorber layer material can be either organic or inorganic halide perovskites, or it can be an inorganic perovskite material. Typically, organic perovskite thin film materials are used, specifically including methylamine lead halide perovskite (CH3NH3PbX3, abbreviated as MAPX), formamidinium lead halide perovskite (NH=CHNH3PbX3, abbreviated as FAPX), or a mixture of formamidinium and methylamine lead halides (chemical formula (NH=CHNH3)). t (CH3NH3) 1-t PbX3, abbreviated as FA t MA 1-t PbX3), etc. Where X is a halogen I, Br, or Cl. Eperovskite film g It can be adjusted according to its chemical composition.

[0025] The electron transport layer can be made of organic or inorganic materials. Typical organic electron transport materials include PCBMs (fullerenes and their derivatives), C... 60 (Fullerenes), BCP (bromocresol purple sodium salt), LiTFSI (lithium bis(trifluoromethanesulfonyl)imide), etc., and not limited to these; typical inorganic electron transport materials include tin oxide (SnO2), zinc oxide (ZnO), titanium dioxide (TiO2), zirconium oxide (ZrO2), etc.; in addition, double or multilayer films of the above materials can also be used to form a composite, such as PCBM / C 60 C 60 / SnO2, ZnO / SnO2, etc.

[0026] The hole transport layer can be made of organic or inorganic materials. Typical organic hole transport materials include Spiro-OMETAD (2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene), PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrene sulfonate), P3HT (polymer of 3-hexylthiophene), and DR3TBDTT (a conjugated small molecule oligothiophene derivative with benzothiophene as the core, dimer thiophene as the arm, and rhodin-terminated, chemical formula C). 102 H 128 N2O2S 14 Typical inorganic hole transport materials include nickel oxide (NiO). x ), molybdenum oxide (MoO) x ), Vanadium oxide (VO) xCopper oxides (CuO, Cu2O), cuprous iodide (CuI), cuprous thiocyanate (CuSCN), etc.

[0027] Sometimes, an interface modification layer is needed between the perovskite absorber layer and the charge (electron or hole) transport layer, or between the charge transport layer and the electrode that leads to the charge, in order to accelerate the extraction and transport of charge and reduce the recombination of photogenerated carriers.

[0028] The specific fabrication processes for the functional layers of semi-finished perovskite solar cells can employ low-temperature solution methods, such as spin-coating, slot-die coating, doctoral-blading, printing coating, spray-coating, meniscus-assisted solution printing, and inkjet printing. Vacuum deposition methods, such as sputtering, atomic layer deposition, and rapid plasma deposition, can also be used. For some functional layers (such as perovskite thin films), if annealing is required, laser annealing is preferred because it is a cold processing technique that will not affect or damage the already fabricated underlying semi-finished silicon module.

[0029] The front electrode (i.e., the front surface electrode) of the top-layer semi-finished perovskite solar cell can be made of metallic materials such as gold, silver, aluminum, or copper, or it can be made of graphene, carbon, or other materials. The electrode is typically fabricated using methods such as sputtering or screen printing.

[0030] After the aforementioned large-area intermediate connecting layer and top-layer semi-finished perovskite solar cell are fabricated, etching and cutting are required. During etching and cutting, care must be taken to preserve the underlying crystalline silicon module from being etched, especially avoiding damage to the flexible substrate layer on the back. This process etches and cuts the large-area semi-finished perovskite solar cell and intermediate connecting layer into smaller perovskite solar cell units and intermediate connecting units. Vertically, the centerlines of the top-layer perovskite solar cell units, intermediate connecting units, and the bottom crystalline silicon solar cell are completely aligned, thus forming independent and separate small-area perovskite / crystalline silicon tandem solar cells. Therefore, in actual etching and cutting, from a vertical perspective, etching and cutting can be performed along the centerline between two adjacent semi-finished crystalline silicon solar cells in the crystalline silicon solar cell module; however, etching and cutting at an appropriate distance from the centerline is also permissible.

[0031] It should be noted that in this etching and cutting process, the various functional thin films (including charge transport layer, interface modification layer, perovskite absorber layer, etc.) and intermediate interconnecting layer materials of the top perovskite solar cell need to be selectively etched away, while the etching and cutting process does not etch or cut the flexible substrate layer on the back of the bottom crystalline silicon solar cell. Therefore, the etching and cutting process needs to have a clear etching selectivity ratio for the materials to be etched and the materials to be retained, while also minimizing the cutting damage to the various parts of the prepared tandem solar cell assembly. It is also important to note that the etching and cutting process must not etch or destroy the previously prepared interconnecting vias. The etching and cutting process can employ techniques such as laser etching, plasma etching, or mechanical grooving.

[0032] Typically, laser etching technology can be used to achieve the selective etching described above by selecting appropriate laser etching parameters. Nd:YVO4 solid-state lasers are generally used, with wavelengths of 355nm, 532nm, or 1064nm, but not limited to these. Pulse widths are typically in the femtosecond, picosecond, or nanosecond range, but also not limited to these. To better achieve the selective etching described above, alternatively, two laser etching processes with identical patterns can be used. The first laser etching removes part of the functional layer of the perovskite solar cell, leaving another part of the functional layer and the intermediate interconnect layer unetched. The second laser etching removes the remaining functional layer and the intermediate interconnect layer, while leaving the flexible substrate layer on the back of the crystalline silicon module unetched. Regarding the selection of the two laser parameters, the process parameters of the second laser etching should allow for a faster etching rate on the material to be etched, while leaving the flexible substrate layer on the back unetched or with extremely weak etching capability.

[0033] After completing the fabrication of the bottom semi-finished crystalline silicon cells, the intermediate connecting layer, and the top semi-finished perovskite cells, the final step is to interconnect and encapsulate the tandem cells to complete the fabrication of the perovskite / crystalline silicon tandem cell module. It's important to note that this encapsulation can be referred to as "module encapsulation," which typically includes front-side encapsulation and back-side encapsulation to form flexible front and back encapsulation layers. Front-side encapsulation, which is the encapsulation of the front surface of the top semi-finished perovskite cells, requires materials that, in addition to flexibility, possess excellent optical anti-reflective properties, as well as good resistance to degradation and aging, UV radiation, mechanical load, water, moisture, and fire, and acid and alkali resistance, ensuring high reliability. The specific encapsulation material is not limited. Typically, flexible polymers such as PDMA (pyromellitic dianhydride), PDMS (polydimethylsiloxane), polyethylene terephthalate (PET), polyethylene dinaphthalate (PEN), POE (polyolefin elastomer), and POB (polyphenylene oxide) can be used. Flexible inorganic encapsulation films such as flexible coated glass can also be used.

[0034] For the crosslinking agent used in the encapsulation of the top-layer semi-finished perovskite solar cell, this application primarily uses silicone rubber. Silicone rubber possesses excellent light transmittance, electrical insulation properties, UV radiation resistance, high and low temperature resistance, chemical corrosion resistance, chemical stability, mechanical properties, and reliability. Silicone rubber also exhibits good crosslinking and sealing properties. This invention uses silicone rubber instead of traditional EVA crosslinking agent to encapsulate solar cell modules, resulting in excellent crosslinking, sealing, plasticity, UV radiation resistance, durability, and electrical insulation properties. Therefore, the photovoltaic module exhibits superior reliability and stable, efficient operation.

[0035] More importantly, encapsulating photovoltaic modules with silicone does not require a lamination process at 140-150℃; instead, it can be cured at room temperature and pressure. Therefore, it has no impact or damage on the already prepared perovskite cell section and the underlying semi-finished crystalline silicon module. The specific method is as follows: silicone is evenly laid between the encapsulation material on the front surface of the top-layer semi-finished perovskite cell and the perovskite cell using methods such as dispensing, coating, spraying, or spin coating. Then, deep curing is performed at room temperature and pressure. The curing process can also be accelerated by increasing the pressure during curing. Due to the good insulation properties of silicone, the silicone filling between the individual perovskite / crystalline silicon tandem cells cut by the aforementioned etching process also provides good electrical isolation between them.

[0036] For perovskite / crystalline silicon tandem solar cells, the leads of the front and back electrodes of each cell are interconnected. Specifically, the electrode leads on the back of the tandem cell are first passed through interconnection vias in the flexible substrate on the back side, and then interconnected. The specific interconnection method is not limited; it can be performed in series or parallel within the module depending on the application requirements. Finally, silicone is used to encapsulate the front encapsulation film of the top cell and the outermost encapsulation film on the back side.

[0037] Finally, conventional techniques are used to install the frame, seal, and install the junction box to ultimately form the flexible perovskite / crystalline silicon tandem solar cell module.

[0038] The present invention has the following beneficial effects:

[0039] 1) This invention integrates the fabrication processes of the bottom layer battery, the top layer battery, and the entire module, providing a new approach to the fabrication of flexible tandem solar cell modules. The fabrication process is simple, greatly reducing the production cost of tandem modules and making it suitable for industrialization.

[0040] 2) Flexible perovskite / crystalline silicon solar cells, which can be bent and folded, are lightweight and expand the application scenarios of high-efficiency tandem solar cells, making their applications more widespread and flexible. A typical application is in building-integrated photovoltaics (BIPV), where the curvature of the tandem cell modules can be designed to match the curvature of the building's shape.

[0041] 3) Flexible perovskite / crystalline silicon tandem solar cell modules consist of a top perovskite cell with a wide bandgap and a bottom crystalline silicon cell with a narrow bandgap. They can utilize photons in the short, medium and long wavelength range of the solar spectrum more comprehensively and efficiently, thereby achieving high cell conversion efficiency and module power generation.

[0042] 4) The structure and type of the top-layer perovskite solar cell are flexible. The bandgap width of the absorption layer can be designed to be optimized according to the needs of the application scenario. This bandgap width of the top-layer perovskite solar cell can be achieved by adjusting the composition of the perovskite thin film material of the absorption layer, so that it can be suitable for different application environments (climate, geography and environment, etc.).

[0043] 5) Flexible perovskite / crystalline silicon tandem solar cell modules can be flexibly fabricated into 2-terminal or 3-terminal types according to the needs of the application scenario. This design is achieved through the specific structure of the underlying crystalline silicon cell, which flexibly broadens the applicability and compatibility of the application scenarios. Attached Figure Description

[0044] Figure 1 A schematic diagram of a flexible perovskite / crystalline silicon tandem solar cell module is shown, illustrating the case where one crystalline silicon bottom cell is considered as one unit. In this diagram, 1 is the back encapsulation layer, 2 is the back flexible substrate layer, 3 is the back electrode of the bottom crystalline silicon cell, 4 is the electrode lead via, 5 is the electrode lead of the bottom crystalline silicon cell's back module, 6 is the electron (or hole) transport layer, 7 is the crystalline silicon substrate, 8 is the hole (or electron) transport layer, 9 is the intermediate connecting layer, 10 is the electron (or hole) transport layer, 11 is the perovskite absorber layer, 12 is the hole (or electron) transport layer, 13 is the front flexible encapsulation layer, 14 is the front electrode of the top perovskite cell, and 15 is the electrode lead of the top perovskite front module.

[0045] Figure 2 Flowchart of the fabrication process for flexible perovskite / crystalline silicon tandem solar cell modules.

[0046] Figure 3. Schematic diagrams before and after etching and cutting during the fabrication process of flexible perovskite / crystalline silicon tandem solar cell modules. The figure shows a schematic diagram of the flexible cell module laid out in a flat manner. Wherein: Figure 3-aThis is a schematic diagram before etching and cutting. In the diagram, 1 is a semi-finished crystalline silicon solar cell, 2 is a large-area intermediate connecting layer, 3 is a large-area top perovskite solar cell, and 4 is a flexible substrate layer on the back.

[0047] Figure 3-b This diagram illustrates the process of completing the front-side encapsulation of the module after etching and cutting. The diagram shows a flexible battery module laid out in a flat configuration. In the diagram, 1 is a semi-finished crystalline silicon cell, 2 is the intermediate connecting unit after etching and cutting, 3 is the top perovskite sub-cell unit after etching and cutting, 4 is the back flexible substrate layer, 5 is the front flexible encapsulation layer, 6 is the back flexible encapsulation layer, 7 is the electrode lead via, and 8 is the interconnect via. It should be noted that after the module encapsulation is completed, the space between adjacent cell sizes in the stacked cells is filled with the front encapsulation material and cross-linking agent. Since both the front encapsulation material and the cross-linking agent have good electrical insulation properties, they effectively provide insulation between cell sizes in the stacked cells. Detailed Implementation

[0048] To better understand the present invention, it will be further described below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0049] Combination Figure 1 As shown in Figure 3, Example 1 presents a method for fabricating a flexible perovskite / crystalline silicon tandem solar cell module. The bottom crystalline silicon cell uses a TOPCon cell, and the top perovskite cell has an absorber layer bandgap of 1.75 eV. The specific fabrication process mainly includes the following stages:

[0050] The first stage involves fabricating the underlying flexible TOPCon battery module. The specific process flow is as follows:

[0051] Step 1. Select a 156mm*156mm (100) crystal orientation n-type single crystal silicon wafer with a thickness of 170 micrometers and a resistivity of 1Ω·cm.

[0052] Step 2. A textured surface with a random pyramidal morphology is prepared on the surface of the n-type silicon wafer using an alkaline texturing method. The process conditions are: 2-3% potassium hydroxide by mass concentration, temperature of 70-75℃, and texturing time of 5-7 minutes.

[0053] Step 3. Fabricate a boron emitter on the front side of the n-type silicon wafer using a method of boron ion implantation combined with thermal annealing. The specific process is as follows. The boron ion implantation dose is 2.10. 15 -5·10 15 cm-2 The energy level is 5-10 keV, the furnace tube annealing temperature is 950-1000℃, the time is 30-60 minutes, and the atmosphere is a mixture of nitrogen and oxygen. After annealing, the surface concentration of the boron emitter junction on the front side of the silicon wafer is 9.10. 19 -1·10 20 cm -3 The sheet resistance is 50-200 Ω / □. After the front boron emitter is fabricated in this step, a layer of borosilicate glass is typically formed on the silicon wafer surface.

[0054] Step 4. Using a single-sided water-floating wet etching process, a small amount of doped borosilicate glass on the back side of the n-type silicon wafer is etched away, followed by polishing of the back side of the silicon wafer. Specifically: First, hydrofluoric acid is used to remove the borosilicate glass on the back side of the silicon wafer. The hydrofluoric acid concentration is 1%-5%, and the cleaning time is 2-7 minutes. Then, a mixed solution of hydrofluoric acid and nitric acid is used to polish the back side of the silicon wafer. In this mixed solution, the nitric acid mass concentration is 40%, the hydrofluoric acid mass concentration is 4%, the solution temperature is 7°C, and the etching time is 10-20 seconds. After chemical etching with the mixed solution of nitric acid and hydrofluoric acid, the textured surface on the back side of the silicon wafer is etched into an acid-polished surface.

[0055] Step 5. Prepare a passivation contact layer on the back side of the n-type silicon wafer. The passivation contact layer includes a tunneling silicon oxide layer and a phosphorus-doped polycrystalline silicon layer, prepared using a PECVD process. The plasma generation method is not limited and can be achieved through radio frequency or microwave discharge. Specifically, SiO2 is prepared... x The temperature for preparing phosphorus-doped amorphous silicon is 250-350℃, and the process gases are silane, nitrous oxide (N2O), and hydrogen. The temperature for preparing phosphorus-doped amorphous silicon is 400-500℃, and the process gases are phosphine, silane, and hydrogen. Then, furnace tube annealing is used to complete the crystallization from amorphous silicon to polycrystalline silicon, as well as the activation and redistribution of phosphorus doping. The annealing temperature is 850-875℃, and the annealing atmosphere is nitrogen. The thickness of the tunneling oxide layer obtained is 1.2-1.6 nm, and the thickness of the phosphorus-doped polycrystalline silicon layer is 75-100 nm; the phosphorus surface concentration of the phosphorus-doped polycrystalline silicon layer is 1.10. 20 cm -3 -3·10 20 cm -3 The sheet resistance is 30-100 Ω / □. In this step, the amount of phosphorus-doped amorphous silicon deposited onto the front side of the silicon wafer by PECVD is very small, and this effect can be eliminated subsequently by wet chemical etching.

[0056] Step 6. A silicon nitride film with a thickness of 100 nm and a refractive index of 2.0 is deposited on the back side of the n-type silicon wafer using a PECVD process. This silicon nitride layer not only serves as a buffer barrier layer for the screen-printed silver paste metallization in Step 8, ensuring that Ag is confined within the phosphorus-doped polycrystalline silicon layer after rapid thermal sintering, but also as a protective layer on the back side of the silicon wafer to effectively block alkaline solution etching in the subsequent Step 7.

[0057] Step 7. Chemically etch away the very small amount of phosphorus-doped amorphous silicon coated around the edge of the front side of the n-type silicon wafer and the borosilicate glass on the front side using wet etching. First, etch away the very small amount of phosphorus-doped amorphous silicon coated around the edge of the front side of the silicon wafer using NaOH solution. The NaOH solution concentration is 0.2%-0.5%, the temperature is 15-20℃, and the etching time is 30-60 seconds. In this alkaline solution etching step, the silicon nitride film deposited on the back side of the silicon wafer in step 6 provides excellent protection for the back side of the silicon wafer; furthermore, the low-concentration alkaline solution etching at room temperature for a short time will not affect the boron emitter junction and textured surface on the front side of the silicon wafer. Then, use a single-sided water-floating etching method to etch the borosilicate glass on the front side using hydrofluoric acid solution. The hydrofluoric acid concentration is 2-10%, and the cleaning time is 2-20 minutes.

[0058] Step 8. Metallize the back side of the n-type silicon wafer using a method combining screen-printed silver paste with rapid thermal processing (RTP). The back-side metallization employs a grid pattern design with a grid line width of 30 μm and a spacing of 1.5 mm between adjacent grid lines (between the center lines). The actual peak sintering temperature is 750℃, the time at peak temperature is 2-4 seconds, and the atmosphere is compressed air.

[0059] Step 9. Laser edge isolation is applied to the perimeter of the semi-finished TOPCon battery to make the perimeter of the battery electrically insulated.

[0060] Step 10. Perform back-side encapsulation on the bottom-layer semi-finished TOPCon battery, mainly including the fabrication of electrode leads and a flexible back substrate layer. Specifically, the back of the prepared bottom-layer semi-finished TOPCon battery is encapsulated. First, the prepared semi-finished TOPCon battery is cut into half pieces (i.e., 1 / 2 pieces) using low-loss laser cutting technology. Then, 144 semi-finished TOPCon half-piece batteries are arranged into a 12*12 module array.

[0061] 1) First, the back silver electrode assembly is wired with metal leads. Copper-chromium alloy, copper-chromium-zirconium alloy, or copper-nickel-chromium alloy can be used. These alloys have good electrical conductivity and excellent resistance to high-temperature oxidation, thus avoiding oxidation during the subsequent fabrication of the intermediate and top perovskite solar cells, thereby ensuring the interconnection performance of the tandem solar cell assembly.

[0062] 2) Flexible substrate encapsulation on the back

[0063] The flexible substrate layer on the back is made of flexible coated glass with good flexibility and mechanical properties. The following two processes are required: (1) A certain number and pattern distribution of electrode lead vias and interconnect vias are etched on the flexible coated glass using low-damage laser etching technology. The diameter of the electrode lead vias and interconnect vias is 0.8 cm. The pattern distribution of the electrode lead vias is within the lower edge of the longitudinal direction of the semi-finished TOPCon battery. The specific pattern distribution can be designed according to the metal electrode distribution on the back of the semi-finished TOPCon battery. The pattern distribution of the interconnect vias is in the lower longitudinal direction of the area between two adjacent semi-finished TOPCon batteries (but cannot be distributed on the center line of the area between two adjacent semi-finished TOPCon batteries or on the adjacent sides). The via etching can be completed using 355 nm nanosecond laser technology. 2) After completing the through-hole etching, the back flexible substrate layer, i.e. the flexible coated glass, is subjected to hydrofluoric acid cleaning treatment with HF mass fraction of 5%-10% for 30-60 minutes, followed by water rinsing and drying. The purpose is to further enhance the barrier ability against laser etching and cutting in step 16 (to prevent it from being etched).

[0064] Next, the metallized leads of the components on the back of the semi-finished TOPCon battery are passed through the electrode lead through-holes in the flexible substrate encapsulation film on the back. Dow Corning's silicone rubber, used in solar cell encapsulation, is used as the crosslinking agent. The prepared semi-finished TOPCon battery and the flexible substrate layer (flexible coated glass) are arranged and laid out at a certain spacing and in an array. The silicone rubber is then uniformly applied between the semi-finished TOPCon battery and the flexible coated glass using a dispensing method. Then, deep curing is performed at 25-50°C for 1-2 hours in a nitrogen atmosphere, allowing the silicone rubber to tightly bond the components together, ensuring full crosslinking, fixation, and sealing of the semi-finished TOPCon battery, silicone rubber, and flexible coated glass. Alternatively, a curing lamination method with slowly increasing pressure can be used to enhance the curing effect and accelerate the curing process. This completes the fabrication of the bottom flexible TOPCon battery module.

[0065] The second stage involves preparing a large-area intermediate connecting layer.

[0066] Step 11. Fabricate an intermediate connecting layer for the tandem battery on the bottom flexible TOPCon battery module. The area of ​​this intermediate layer is the same as that of the bottom flexible TOPCon battery module (Note: the fabrication process for the top perovskite battery is the same below). Indium-doped zinc oxide (IZO) is used as the intermediate layer material and fabricated by DC magnetron sputtering. An In / Zn alloy target (with Zn accounting for 36.79 wt%) with a purity higher than 99.99% is used. The target-substrate spacing is 90-100 mm, and the substrate temperature is room temperature (25°C). The base vacuum is 1.10. -3 The sputtering gas was a mixture of Ar and O2 (both with purities higher than 99.99%), and the sputtering pressure was stabilized at 0.15 Pa. The sputtering current was 100 mA, and the sputtering voltage was 400 V. The prepared IZO had a thickness of 100 nm, a sheet resistance of 50-100 Ω / □, and an average transmittance of ~87%.

[0067] The third stage involves the fabrication of a large-area top-layer semi-finished perovskite solar cell.

[0068] Step 12. Fabrication of the electron transport layer using magnetron sputtering of SnO2. First, a 10-minute pretreatment was performed using a single-sided water-floating ultraviolet ozone cleaner, followed by magnetron sputtering. A tin target with a purity higher than 99.99% was used, with a target-to-substrate spacing of 70-100 mm and a substrate temperature of 25°C. The sputtering gas was a mixture of Ar and O2 (both with a purity higher than 99.99%). The base vacuum was 8.10... -4 Pa, sputtering pressure was 0.3 Pa. First, pre-sputter for 5 minutes to remove oxides from the target surface; then SnO2 was prepared by sputtering at a power of 1000 W and a thickness of 30 nm.

[0069] Step 13. Prepare a perovskite absorber layer film using methylamine lead halide perovskite, i.e., CH3NH3Pb(I x Br 1-x )3, E gThe perovskite film was prepared in the range of 1.6-1.9 eV. It was prepared using spin coating, employing a perovskite precursor solution composed of PbI₂, PbBr₂, CH₃NH₃I, DMF (N,N-dimethylformamide), and DMSO (dimethyl sulfoxide). Chlorobenzene (as an anti-solvent to wash away DMF) was dropped onto the perovskite film during spin coating at a speed of 3000 rpm. After spin coating, the film was heated at 70-80°C for 30 minutes in a nitrogen atmosphere. Annealing was then performed using a femtosecond Nd:YVO₄ solid-state laser with a wavelength of 800 nm, a pulse width of 140 fs, and a repetition rate of 80 MHz, under a nitrogen atmosphere. After laser annealing, the perovskite film underwent a phase transformation. It should be noted that due to the localized heat treatment characteristics of laser "cold processing," only the perovskite film was subjected to laser heat treatment; the underlying layers beneath the perovskite absorber remained unaffected. The prepared perovskite thin film CH3NH3Pb(Br 0.4 I 0.6 )3 of E g It has a voltage of 1.75 eV and a thickness of 500 nm.

[0070] Step 14. Prepare the hole transport layer of the top perovskite solar cell using PTAA, i.e., bis(4-phenyl)(2,4,6-trimethylphenyl)amine. Spin-coating was used; the PTAA solution was spin-coated at 5000 rpm, then annealed at 80°C for 10 minutes under nitrogen atmosphere. After annealing, the layer was cooled to room temperature. The thickness of the PTAA layer was 50 nm.

[0071] Step 15. Metallize the front surface of the top-layer perovskite solar cell using magnetron sputtering of Ag to form grid-type Ag electrodes. A photomask sputtering process is used, with the photomask made of graphite. In the sputtering process, the solid portion of the photomask prevents sputtered Ag atoms from reaching the substrate, while the hollow portion allows sputtered Ag atoms to reach the substrate; therefore, the photomask pattern is the Ag grid pattern. The silver target purity is 99.99%, the substrate temperature is room temperature (25°C), the distance between the target and substrate is 50 mm, the sputtering gas is argon (99.99% purity), and the base vacuum is 5.10. -5 The sputtering power was 160W. The sputtered Ag layer thickness was 200nm, and the sheet resistance was 0.25Ω / □. Then, tin-plated silver or copper strips were used to draw out the front surface metal electrodes of the top perovskite cell. In this example, a two-terminal design was used, specifically, the electrodes of the top perovskite cell led out photogenerated holes, and the bottom TOPCon sub-cell led out photogenerated electrons.

[0072] Step 16. Perform laser etching to cut the large-area top-layer perovskite solar cell and intermediate connection layer. Selectively etch away the functional thin films (including charge transport layer, interface modification layer, perovskite absorber layer, etc.) and intermediate layer materials of the top-layer perovskite solar cell, leaving only the flexible substrate layer (flexible coated glass) on the back of the bottom flexible TOPCon solar cell module unetched. This process etches and cuts the large-area top-layer perovskite solar cell and intermediate connection layer into small-area perovskite solar cell units and intermediate connection units, forming independent and separate small-area perovskite / crystalline silicon tandem solar cells in the vertical direction. It is important to note that the laser etching process must not etch or damage the previously prepared interconnecting vias; this can be achieved through precise scanning techniques in laser etching.

[0073] The specific laser etching process is as follows: Using a flexible laser beam deflection, precise focusing, and a high-precision aligned camera system, the laser beam precisely scans and etches along a large area of ​​flexible stacked solar cells. Specifically, the laser etching cutting pattern, viewed vertically, is etched along the center line between every two adjacent TOPCon cells in the "bottom-layer semi-finished TOPCon cell module," thereby etching and cutting the large-area top-layer perovskite cell and intermediate connecting layer into small patterns with an area roughly equal to that of the bottom-layer TOPCon cell, such as... Figure 3-b As shown. Based on the laser etching pattern, two laser etching processes are employed. The first laser etching removes the hole transport layer PTAA, the perovskite absorber layer, and the electron transport layer SnO2 of the top perovskite solar cell; the second laser etching removes the intermediate interconnect layer IZO. The process parameters for the two laser etching processes are as follows: For the first process, an Nd:YVO4 solid-state laser is used with a wavelength of 532 nm, a pulse width of 10 ns, and a repetition frequency of 10-20 kHz. A nitrogen atmosphere is used during the laser process. For the second process, an Nd:YVO4 solid-state laser is used with a wavelength of 1064 nm, a pulse width of 10 ns, and a repetition frequency of 10-20 kHz. A nitrogen atmosphere is used during the laser process.

[0074] The fourth stage involves interconnecting and encapsulating the tandem solar cells to complete the fabrication of flexible perovskite / crystalline silicon tandem solar cell modules.

[0075] Step 17. Interconnect the leads of the front and back electrodes of each unit area of ​​the tandem cell. In the interconnection process, first, the electrode leads of the back of the tandem cell are passed through the previously prepared interconnect vias. Then, interconnection is performed between different small-area tandem cells. In this example, the bottom TOPCon cell module uses a 12*12 array composed of 144 half-cells. The interconnection method is that the small tandem cells in 12 rows are connected in series, and the cells in 12 columns are arranged in parallel. After interconnection, the front and back of the tandem cells are encapsulated, i.e., module encapsulation. The front encapsulation film uses PDMS (polydimethylsiloxane) and flexible coated glass (outermost layer of the front), and the outermost encapsulation film on the back uses polyimide (PI). The crosslinking agent is Dow Corning's silicone rubber used in solar cell encapsulation. Specifically, the encapsulation process involves uniformly laying the flexible coated glass, PDMS encapsulation film, the prepared perovskite / crystalline silicon tandem cell, and polyimide (PI), and then uniformly coating the silicone rubber between the layers using a dispensing method. Then, deep curing is performed at 25-50℃ for 1-2 hours in a nitrogen atmosphere, allowing the silicone to bond the components tightly together and ensuring full cross-linking, fixation, and sealing of the encapsulation film, silicone, and semi-finished tandem solar cells. Alternatively, a curing lamination method with slowly increasing pressure can be used to enhance the curing effect and accelerate the curing process. Because of its excellent insulating properties, the silicone filling the spaces between the discrete perovskite / crystalline silicon tandem solar cells, as cut by laser etching in step 16, also provides good electrical isolation between them.

[0076] Step 18. Install the frame, seal, and install the junction box using conventional techniques to form the final flexible perovskite / crystalline silicon tandem solar cell module. In specific applications, the tandem solar cell of this application can therefore be designed to have the same curvature (i.e., flexibility) as the application scenario's external shape.

[0077] Furthermore, Example 2 discloses a flexible perovskite / crystalline silicon tandem solar cell module, which is prepared using the method described in Example 1. The specific structure will not be described here.

[0078] Finally, it should be noted that although the embodiments of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments and application fields described above. The specific embodiments described above are merely illustrative and guiding, used to help understand the method and core ideas of the present invention, and are not restrictive. Those skilled in the art, under the guidance of this specification, can make many changes, improvements, and equivalent implementations in specific embodiments and application scope without departing from the principles and scope of protection of the claims, and these should also be considered within the scope of protection of the present invention.

Claims

1. A method for fabricating a flexible perovskite / crystalline silicon tandem solar cell module, characterized in that, Includes the following steps: Prepare several semi-finished crystalline silicon solar cells, wherein the semi-finished crystalline silicon solar cells only have a back electrode; Laser edge isolation is applied to the periphery of the semi-finished crystalline silicon cell to make the periphery electrically insulated. The semi-finished crystalline silicon cell is back-encapsulated to obtain a bottom flexible crystalline silicon cell module. The back-encapsulation includes preparing back electrode leads and a back flexible substrate layer. The back flexible substrate layer has several electrode lead through-holes located in the region below the longitudinal direction of the semi-finished crystalline silicon cell and several interconnecting through-holes located in the region between adjacent semi-finished crystalline silicon cells. The material of the back flexible substrate layer is any one of polyethylene terephthalate, polyimide, polyethylene naphthalate, and polyvinyl alcohol; or the flexible back substrate layer is any one of flexible stainless steel, flexible metal foil, and flexible coated glass. An intermediate connection layer is fabricated on the bottom flexible crystalline silicon battery module. The intermediate connection layer is used for optical coupling and electrical coupling between the semi-finished crystalline silicon battery and the semi-finished perovskite battery, and its area completely covers the bottom flexible crystalline silicon battery module. A top-layer semi-finished perovskite solar cell is prepared on the intermediate connecting layer. The area of ​​the semi-finished perovskite solar cell completely covers the intermediate connecting layer. The semi-finished perovskite solar cell has only a front electrode. The pattern and distribution of the front electrode match the back electrode of the bottom flexible crystalline silicon solar cell module. The semi-finished perovskite solar cells and intermediate connecting layers are etched and cut from top to bottom to obtain several perovskite solar cell units and intermediate connecting units that are the same number of semi-finished crystalline silicon solar cells in the bottom flexible crystalline silicon solar cell module. This forms several independent and separate perovskite / crystalline silicon stacked solar cells in the vertical direction. The perovskite / crystalline silicon tandem solar cell is encapsulated to obtain the flexible perovskite / crystalline silicon tandem solar cell module. The module encapsulation includes the preparation of front electrode leads, a front flexible encapsulation layer, and a back flexible encapsulation layer.

2. The preparation method according to claim 1, characterized in that, The semi-finished crystalline silicon solar cell is a cell of N-1, where N ≥ 2.

3. The preparation method according to claim 1, characterized in that, The back electrode lead of the semi-finished crystalline silicon solar cell is any one of copper-chromium alloy, copper-chromium-zirconium alloy, copper-chromium-tellurium alloy, nickel-copper-silicon alloy, copper-nickel-chromium alloy, nickel-chromium-iron alloy, and copper-platinum alloy.

4. The preparation method according to claim 1, characterized in that, The intermediate connecting layer is made of any one of tin-doped indium oxide, indium-doped zinc oxide, or aluminum-doped zinc oxide; the intermediate connecting layer is prepared by sputtering, atomic layer deposition, or rapid plasma deposition.

5. The preparation method according to claim 1, characterized in that, The preparation process of the semi-finished perovskite solar cell includes an annealing treatment, which is a laser annealing process.

6. The preparation method according to claim 1, characterized in that, When etching and cutting the semi-finished perovskite solar cells and intermediate interconnecting layers from top to bottom, the etching and cutting are performed along the center line of the adjacent semi-finished crystalline silicon solar cells in the bottom flexible crystalline silicon solar cell module; the interconnecting vias are located in areas that avoid the center line, and their diameter is 0.2 cm to 1 cm.

7. The preparation method according to claim 1, characterized in that, The etching and cutting process adopts any one of laser etching, plasma etching, or mechanical grooving. When the etching and cutting process adopts laser etching, the laser etching is completed in two steps. The first etching removes part of the functional layer of the semi-finished perovskite solar cell, and the second etching removes the remaining functional layer and intermediate connection layer of the semi-finished perovskite solar cell.

8. The preparation method according to claim 1, characterized in that, The front flexible encapsulation layer is fixedly connected to the semi-finished perovskite battery via silicone rubber, and the back flexible encapsulation layer is fixedly connected to the underlying flexible crystalline silicon battery module via silicone rubber; the silicone rubber is cured at room temperature and pressure.

9. The preparation method according to any one of claims 1 to 8, characterized in that, At least two sets of intermediate connecting layers and semi-finished perovskite cells are prepared on the bottom flexible crystalline silicon cell module, which are arranged alternately in the vertical direction. Except for the top layer, the semi-finished perovskite cells do not need to be fabricated with front electrodes.

10. A flexible perovskite / crystalline silicon tandem solar cell module, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 9.

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