Perovskite-topcon four-terminal laminated cell flexible assembly structure and packaging method

Abstract

This invention discloses a flexible perovskite-TOPCon four-terminal tandem solar module structure and encapsulation method, relating to the field of photovoltaic technology. The module includes an integrated front panel perovskite top cell, a TOPCon bottom cell, an adhesive layer, a backsheet, and circuit components. The integrated front panel is composed of a polymer plastic film substrate, a dense metal oxide coating, and an ultraviolet cutoff film. The top and bottom cells are bonded together with an adhesive film, and a composite structure of adhesive film, fiber cloth, and adhesive film is provided between the bottom cell and the backsheet. The circuit adopts a fully parallel design, with busbars connecting the positive and negative terminals of the top and bottom cells to achieve dual-line lead-out. The module edges and busbar lead-out positions are sealed with butyl adhesive, and a dedicated lead-out cover is used. The encapsulation method includes front panel preparation, cell preparation, stacking, circuit connection, sealing, and lamination molding steps. This invention makes the module flexible and thin, improves photoelectric conversion efficiency and solar energy utilization, simplifies the circuit and inverter system, prevents moisture intrusion, adapts to existing production lines, and expands application scenarios.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a flexible module structure and packaging method for a perovskite-TOPCon four-terminal tandem solar cell. Background Technology

[0002] As an important development direction of next-generation photovoltaic technology, perovskite solar cells have significant advantages such as high efficiency, low cost, flexibility and thinness due to their unique ABX3 crystal structure. Their stacked combination with crystalline silicon solar cells has become the core path to improve the efficiency of solar energy utilization. At present, the mainstream stacked structures include two types: integrated and mechanical stacking. Among them, four-terminal stacked solar cells have greater application potential due to their characteristics such as flexible selection of sub-cell bandgap width, no need for current matching, and stronger compatibility.

[0003] However, existing perovskite-crystalline silicon four-terminal tandem solar cell technologies still have many unresolved issues, which severely restrict their industrialization and application expansion:

[0004] Currently, perovskite cells in four-terminal tandem modules are mostly deposited on the glass surface and encapsulated using double-glass or single-glass methods. The inherent characteristics of the glass substrate result in heavy modules, making them unsuitable for complex installation environments such as roofs with poor load-bearing capacity, mobile energy equipment, and curved buildings. This greatly limits the application boundaries of photovoltaic modules. At the same time, the heavy nature of glass encapsulation also increases the labor and material costs during transportation and installation, reducing the ease of construction. Although flexible polymer material encapsulation has entered the research and development stage, a mature flexible encapsulation solution for perovskite-TOPCon four-terminal tandem cells has not yet emerged.

[0005] Existing tandem modules either fail to fully utilize the spectral complementarity between perovskite and crystalline silicon, resulting in low solar energy utilization, or their structural design requires specialized production equipment, necessitating large-scale modifications for crystalline silicon module manufacturers to achieve mass production, significantly raising the barrier to technology implementation. Furthermore, existing solutions lack effective design for extending power gain, failing to further explore the efficiency potential of the modules.

[0006] Traditional four-terminal modules use a four-wire lead-out mode, which makes the junction box circuit design complex. The power station needs to be equipped with two inverter systems, which significantly increases the system cost and design difficulty. Although some solutions have attempted to achieve dual-wire lead-out by bending the busbar, the bent structure is prone to deformation and desoldering in harsh environments such as strong winds and uneven snow pressure, which affects the power generation stability of the module. At the same time, some solutions lack insulation isolation design between the busbar and the battery cell, as well as reasonable layout of the lead-out positions, which poses electrical safety hazards.

[0007] The halide perovskite materials used in the perovskite light-absorbing layer are extremely sensitive to water vapor and oxygen. Such substances in the external environment can cause material degradation and thermal decomposition, resulting in irreversible performance degradation of the battery. Some existing solutions lead out current by opening a hole in the middle of the backsheet. However, this opening becomes the main channel for water vapor intrusion, exacerbating the degradation of the perovskite material. Furthermore, traditional sealing designs mostly only target the edges of the module, lacking targeted protection for the lead-out locations, and thus failing to form a comprehensive water and oxygen barrier system.

[0008] Therefore, this application proposes a flexible module structure and packaging method for perovskite-TOPCon four-terminal stacked solar cells. Summary of the Invention

[0009] One objective of this invention is to propose a flexible perovskite-TOPCon four-terminal tandem solar cell module structure and packaging method. This invention enables a flexible and lightweight module design that balances structural strength and application flexibility, improves the comprehensive utilization rate of solar spectrum and photoelectric conversion efficiency, and achieves dual-wire lead-out of the four-terminal module through optimized circuit design to simplify the configuration of junction boxes and power station inverter systems. At the same time, it constructs a comprehensive sealed protection system to prevent the degradation of perovskite materials caused by the intrusion of water vapor and oxygen. It is compatible with existing crystalline silicon module manufacturing equipment to lower the threshold for industrialization transformation, thereby expanding the application scenarios of photovoltaic modules and ensuring the long-term stable operation of the modules.

[0010] According to an embodiment of the present invention, a flexible module structure of perovskite-TOPCon four-terminal stacked solar cell includes an integrated front perovskite top cell, a TOPCon bottom cell, an adhesive layer, a backsheet, circuit components, a sealing structure, and a lead wire cover.

[0011] The integrated front panel perovskite top cell consists of, from the outside to the inside, an ultraviolet cutoff film layer, an adhesive layer, a dense metal oxide coating layer, a polymer plastic film substrate, an ITO conductive film layer, and a perovskite cell layer. The dense metal oxide coating layer is prepared by vacuum deposition technology, and the ultraviolet cutoff film layer and the dense metal oxide coating layer are composited by an adhesive layer.

[0012] The adhesive layer includes a first adhesive film and a composite adhesive structure. The first adhesive film is sandwiched between the top battery and the bottom battery. The composite adhesive structure is composed of a second adhesive film, a fiber cloth, and a second adhesive film. The composite adhesive structure is used to bond the bottom battery to the backsheet. The backsheet has water-blocking and oxygen-barrier functions.

[0013] The circuit assembly is a fully parallel structure, including a busbar group and an insulating strip. The busbar group is divided into a positive busbar group and a negative busbar group, which are respectively connected to the positive and negative terminals of the top battery and the bottom battery. The top and bottom battery leads are staggered and meet the creepage distance. The insulating strip is located between the busbar and the battery cell.

[0014] The sealing structure is butyl rubber, which is laid all around the perimeter of the component and additionally laid at the outlet of the busbar group;

[0015] The lead-out cover is made of composite material, with a fluorine film bonded to the air surface and EVA coated on the component surface. The EVA surface is laminated and bonded to the back sheet. The positive and negative busbar groups are led out from the corresponding openings of the lead-out cover and connected to the integrated junction box to achieve dual-line lead-out.

[0016] Furthermore, the polymer plastic film substrate is any one of PET, PEN, or PI, and the dense metal oxide coating is... or Any one of the following, wherein the dense metal oxide coating is free of pinhole defects, ensuring water and oxygen barrier effects.

[0017] Furthermore, the ultraviolet blocking film layer is any one of PVDF, ETFE or modified PET, which can specifically block short-wavelength UVA and UVC light without affecting the transmission of visible light. The adhesive layer is an acrylic resin adhesive layer, which is used to achieve a firm composite between the ultraviolet blocking film layer and the dense metal oxide coating.

[0018] Furthermore, the backsheet is a transparent water-blocking backsheet, allowing sunlight to reach the back of the bottom cell. The power gain of the module is achieved through back-side light absorption. The water-blocking and oxygen-barrier properties of the backsheet work synergistically with the dense metal oxide coating to enhance the overall protection effect of the module.

[0019] Furthermore, the fabrication process of the perovskite solar cell layer includes P1 etching, P2 etching, and P3 etching in sequence;

[0020] P1 etching occurs in the ITO conductive film layer, which is used to divide the large-area ITO conductive film into multiple independent battery cell conductive regions.

[0021] P2 etching occurs between the perovskite layer and the hole transport layer to achieve hole transport layer isolation between adjacent cell units;

[0022] P3 etching occurs between the electron transport layer and the metal electrode to isolate the electron transport layer from the metal electrode of adjacent cell cells.

[0023] A method for encapsulating a flexible perovskite-TOPCon four-terminal tandem solar cell module includes the following steps:

[0024] S1. Integrated front panel preparation: First, a polymer plastic film is selected as the substrate. Metal oxides are deposited on its outer surface using vacuum deposition technology to form a dense coating without pinholes, obtaining a high water-resistant and oxygen-barrier material. Then, an adhesive layer is uniformly coated on the surface of the dense coating. The UV cut-off film is bonded to the adhesive layer and a composite film is formed through a composite process. The composite film is then pretreated. Adhesive tape is applied along the width direction and the length direction of the roll of the composite film to form the component sealing and bonding surface. Finally, an ITO conductive film is prepared on the inner side of the composite film substrate using roll-to-roll magnetron sputtering technology. After preparation, the film is coated and rolled up to obtain the integrated front panel substrate.

[0025] S2. Fabrication of perovskite top cell: On the ITO conductive film of the integrated front panel substrate, each functional layer is fabricated in sequence according to the structure of transparent conductive electrode, hole transport layer, perovskite light-absorbing layer, electron transport layer and metal electrode. During the process, P1 etching, P2 etching and P3 etching are completed in sequence. After etching, the isolation tape applied in the pretreatment stage is removed to obtain the integrated front panel perovskite top cell.

[0026] S3, Module Stacking: A first adhesive film is laid flat on the metal electrode side of the perovskite top cell. The TOPCon bottom cell is then attached to the side of the first adhesive film away from the top cell, ensuring that the bottom cell and the top cell are aligned. On the side of the TOPCon bottom cell away from the top cell, a second adhesive film, a fiber cloth, and another second adhesive film are laid flat in sequence to form a composite adhesive layer. The backsheet is then attached to the side of the composite adhesive layer away from the bottom cell to complete the module stacking.

[0027] S4. Circuit connection: A fully parallel circuit is constructed using busbars. The positive busbar of the top battery is fixedly connected to the positive busbar of the bottom battery to form a positive busbar group. The negative busbar of the top battery is fixedly connected to the negative busbar of the bottom battery to form a negative busbar group. An insulating strip is set in the contact area between the busbar and the battery cell to ensure that the distance between the lead-out positions of the top battery and the bottom battery meets the creepage distance requirements.

[0028] S5. Sealing and cover plate installation: Apply butyl rubber continuously along the four edges of the component to form a circumferential seal. Apply additional butyl rubber at the lead-out positions of the positive and negative busbar groups to form a lead-out end seal. With the EVA layer of the lead-out cover plate facing the back plate, align and cover the positive and negative lead-out positions, ensuring that the positive busbar group corresponds to the positive opening of the lead-out cover plate and the negative busbar group corresponds to the negative opening of the lead-out cover plate.

[0029] S6. Lamination Molding: The stacked and sealed components with cover plates installed are placed in a laminator with a vacuum heating chamber and a cooling chamber. First, a vacuum is drawn and heated in the vacuum heating chamber to ensure that the layers are fully bonded. Then, pressure is applied to ensure that the layers are firmly bonded. Finally, the components are sent to the cooling chamber to cool to room temperature to complete the component molding. The positive electrode busbar is led out from the positive electrode opening to form the positive electrode lead wire, and the negative electrode busbar is led out from the negative electrode opening to form the negative electrode lead wire. The positive and negative electrode leads wires are connected to the corresponding electrodes of the integrated junction box to realize the dual-wire lead wire of the four-terminal component.

[0030] Furthermore, during the pretreatment of the composite film in step S1, the tape applied along the width direction of the composite film corresponds to the sealing and bonding surface in the width direction of the component, and the tape applied along the length direction of the roll corresponds to the sealing and bonding surface in the length direction of the component. The bonding strength between the tape and the composite film meets the bonding requirements in the subsequent encapsulation process and does not affect the flexibility of the component.

[0031] Furthermore, in step S2, the spacing of P1 etching is determined according to the current requirements of the module design to control the area of ​​the perovskite single cell. The gap width of P1 etching is determined according to the overall size of the module to adapt to the subsequent module cutting and processing requirements. The depths of P2 etching and P3 etching are controlled between corresponding layers to ensure that adjacent functional layers are not damaged.

[0032] Furthermore, in step S5, the lead-out cover plate uses PET as the substrate, the fluoropolymer film is fixed to the air surface of the substrate by an adhesive bonding process, and the EVA layer is fixed to the component surface of the substrate by a coating process. The positions of the positive and negative openings of the lead-out cover plate are precisely corresponding to the lead-out positions of the positive and negative busbar groups.

[0033] Furthermore, in the lamination process of step S6, the purpose of vacuum heating is to remove air from the inside of the component and soften the adhesive layer, the purpose of pressure treatment is to make the structure of each layer tightly bonded, and the purpose of cooling treatment is to make the component molded and maintain structural stability.

[0034] The beneficial effects of this invention are:

[0035] 1. In this invention, a perovskite-TOPCon four-terminal stacked flexible module is constructed by combining a polymer plastic film substrate with a dense metal oxide coating and an ultraviolet cut-off film to form an integrated front panel, and by using flexible bonding and encapsulation processes. This structural design takes into account both the flexibility and structural strength of the module, making the module thinner and lighter, and adaptable to a variety of complex installation environments, effectively expanding the application range of photovoltaic modules. At the same time, the lightweight characteristics also help reduce the overall cost of transportation and installation, and improve the convenience of construction.

[0036] 2. This invention employs a four-terminal stacked design of perovskite and TOPCon cells, utilizing their different spectral absorption characteristics to fully capture different wavelength ranges of sunlight, thereby improving the overall utilization rate of sunlight and enhancing the photoelectric conversion efficiency of the module. In addition, the module structure design is compatible with the existing production equipment of crystalline silicon module manufacturers, eliminating the need for large-scale addition of specialized equipment to achieve production, thus reducing the difficulty of industrialization. Furthermore, specific types of backsheets can be selected to further enhance module power through back-side light absorption, achieving additional efficiency gains.

[0037] 3. In this invention, the positive and negative terminals of the top and bottom batteries are connected separately through a fully parallel circuit structure and busbar design to achieve dual-line output, which simplifies the wiring design of the module and the circuit layout of the power station, and reduces the design complexity of the inverter system. At the same time, the insulation isolation design between the busbar and the battery cell, and the reasonable layout of the top and bottom battery output positions, ensure the safety and stability of the circuit operation and guarantee the long-term high-efficiency power generation of the module.

[0038] 4. In this invention, a comprehensive protection system is constructed by the all-round sealing design of the four edges of the component and the additional sealing treatment at the busbar outlet position, combined with the edge outlet method. This system effectively blocks external moisture, oxygen and other substances from entering the component. This design can reliably protect the perovskite material, delay the degradation of battery performance, extend the service life of the component, and ensure the stable operation of the component in various environments. Attached Figure Description

[0039] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0040] Figure 1 This is a schematic diagram of the structure of a perovskite-TOPCon four-terminal stacked flexible battery module proposed in this invention;

[0041] Figure 2 This is a distribution diagram of the effective area of ​​the perovskite cell in the flexible module structure of the perovskite-TOPCon four-terminal stacked cell proposed in this invention.

[0042] Figure 3 This is a cross-sectional view of a flexible perovskite-TOPCon four-terminal stacked battery module structure proposed in this invention;

[0043] Figure 4 This is a diagram showing the position of the lead-out cover plate of a perovskite-TOPCon four-terminal stacked flexible module structure proposed in this invention.

[0044] Figure 5This is a circuit design diagram of a flexible perovskite-TOPCon four-terminal stacked battery module structure proposed in this invention;

[0045] Figure 6 This is a partial view of the positive, negative and lead-out positions of a perovskite-TOPCon four-terminal stacked flexible module structure proposed in this invention.

[0046] Figure 7 This is a schematic diagram of the encapsulation method for a perovskite-TOPCon four-terminal stacked flexible module structure proposed in this invention. Detailed Implementation

[0047] To make the technical means and objectives and effects of the present invention easier to understand, the embodiments of the present invention will be described in detail below with reference to specific illustrations.

[0048] Example 1

[0049] like Figure 1-6 As shown, this invention discloses a flexible perovskite-TOPCon four-terminal tandem solar cell module structure. This structure specifically addresses the problems of existing four-terminal tandem solar cell modules, such as large weight, poor sealing reliability, and complex circuit design. Through integrated structural design, optimized bonding protection, and circuit layout, it achieves a synergistic improvement in flexibility, high stability, and high efficiency. Specific technical details are as follows:

[0050] The component includes an integrated front perovskite top cell, a TOPCon bottom cell, an adhesive layer, a backsheet, circuit components, a sealing structure, and a lead wire cover. The components are precisely fitted together to form a complete flexible laminated system.

[0051] Please see Figure 1 The integrated front panel perovskite top cell has a multi-layer composite flexible structure, consisting of an ultraviolet cutoff film layer, an adhesive layer, a dense metal oxide coating layer, a polymer plastic film substrate, an ITO conductive film layer, and a perovskite cell layer from the outside to the inside. This integrated design ensures both water and oxygen barrier performance and anti-aging properties, while also taking into account the flexibility of the module.

[0052] For the polymer plastic film substrate, PET is preferred, with a thickness of 100-150μm. This thickness meets the requirements for flexible bending while providing sufficient mechanical support. For applications with higher temperature resistance requirements, PEN or PI can be used instead, with a thickness maintained at 80-120μm. For the dense metal oxide coating, [the following is a list of coating types / materials]. Prepared using vacuum deposition technology, with the vacuum level controlled during the deposition process. The deposition rate is 0.5-1 nm / s, the coating thickness is 20-50 nm, and the coating is free of pinhole defects. Water vapor transmission rate is ≤ It can effectively block the intrusion of external moisture and oxygen. If further improvement in barrier performance is required, you can choose... The coating thickness was adjusted to 15-30nm.

[0053] The UV-blocking film layer is made of PVDF with a thickness of 20-50μm and a UV blocking rate of ≥99%, specifically blocking short-wavelength UVA and UVC rays. Simultaneously, the visible light transmittance is ≥88%, without affecting the battery's absorption of effective light. The adhesive layer is made of acrylic resin, uniformly coated using a roller coating process, with a thickness of 10-20μm. After coating, it undergoes hot pressing at 80-90℃ for 10-15 minutes to achieve a strong bond between the UV-blocking film layer and the dense metal oxide coating, with a peel strength ≥ This ensures that the integrated front panel does not separate into layers during long-term use.

[0054] The adhesive layer includes a first adhesive film and a composite adhesive structure. The first adhesive film is sandwiched between the top and bottom cells and is a POE adhesive film with a basis weight of [missing information]. With a thickness of 500μm, this adhesive film possesses excellent insulation and cushioning properties, effectively preventing the bottom cell solder ribbon from puncturing the film and contacting the top cell, thus preventing short circuits. It also absorbs external impact energy, reducing mechanical damage to the TOPCon bottom cell from harsh environments such as strong winds and snow pressure. The composite bonding structure consists of two layers of second adhesive film and one layer of fiber cloth. The second adhesive film is also made of POE, with the same basis weight as the first adhesive film. The fiber cloth is made of glass fiber, with a thickness of 30-50μm and a tensile strength ≥300MPa. It is sandwiched between the two layers of second adhesive film to form a "second adhesive film-fiber cloth-second adhesive film" composite structure. This structure bonds the bottom cell to the backplate using a hot-pressing process, achieving a bonding strength ≥2.0N / mm. Simultaneously, the fiber cloth disperses stress, preventing the cell from cracking due to bending or vibration.

[0055] The backsheet is a transparent water-resistant backsheet made of PET-based composite film with a thickness of 120-150μm and a water vapor transmission rate of ≤ On the one hand, it works synergistically with the dense metal oxide coating to form a comprehensive water-blocking and oxygen-barrier protection system. On the other hand, its transparency allows sunlight to pass through the backsheet and reach the back of the TOPCon bottom cell, achieving a 1-2 percentage point increase in module power through back-side light absorption. If applied to scenarios with extremely high water-blocking requirements, it can be replaced with an aluminum-containing backsheet to further reduce water vapor transmission rate to ≤ .

[0056] Please see Figure 6The circuit components are in a fully parallel structure, including busbar groups and insulating strips. The busbar groups are divided into positive and negative busbar groups. The busbars are flat structures with copper substrates plated with tin, with a width of 12mm, a thickness of 0.6mm, and a tin plating layer thickness of 5-8μm, which can reduce contact resistance and improve corrosion resistance. The positive busbar group is formed by fixing the positive busbar of the top battery to the positive busbar of the bottom battery through an ultrasonic welding process. The welding temperature is 180-200℃, the welding time is 0.5-1s, and the welding strength is ≥10N. The negative busbar group is connected in the same way to ensure stable current transmission.

[0057] The lead-out positions of the top and bottom batteries are staggered, and the distance measured by a ranging tool is 10.4mm, which meets the creepage distance requirements of GB / T19064-2008 standard and effectively avoids the risk of leakage. The insulating tape is made of polyimide tape with a thickness of 25-50μm and a width 3mm wider than the busbar. It is pasted on the contact area between the busbar and the battery cell to achieve insulation isolation between the busbar and the battery cell. The breakdown voltage is ≥30kV / mm to prevent short circuit faults.

[0058] Please see Figure 3 The fabrication process of the perovskite solar cell layer includes P1, P2, and P3 etching, all using nanosecond laser etching technology with a laser wavelength of 532nm. P1 etching occurs on the ITO conductive film layer, with an etching spacing of 4-6mm determined based on the module's design current requirements. The etching gap width is 1.5-2.5mm, used to divide the large-area ITO conductive film into multiple independent conductive regions for each solar cell. The area of ​​each unit is controlled within a certain range. The first etching process ensures uniform current density; the second etching process occurs between the perovskite layer and the hole transport layer, with an etching depth of 300-500 nm. This process only cuts off the connection between the hole transport layer and the perovskite layer, achieving hole transport layer isolation between adjacent battery cells; the third etching process occurs between the electron transport layer and the metal electrode, with an etching depth of 200-400 nm. This process cuts off the connection between the electron transport layer and the metal electrode, ensuring that each battery cell works independently. After etching, residual debris is removed by plasma cleaning to avoid affecting battery performance.

[0059] The sealing structure uses hot-melt butyl rubber with a melting temperature of 80-100℃, exhibiting excellent waterproof sealing and weather resistance. It is continuously applied along the perimeter of the module using an extrusion coating process, with a coating width of 5-15mm and a thickness of 0.8-1.5mm, forming a circumferential sealing strip to prevent external moisture, dust, and other impurities from intruding from the module edges. Simultaneously, an additional 10mm wide and 0.8-1.5mm thick butyl rubber strip is applied at the lead-out positions of the positive and negative busbar groups, forming a double seal at the lead-out ends. This design specifically addresses the problem of moisture ingress through the opening in the middle of the backsheet in existing technologies. Immersion tests have verified that no moisture intrusion occurred after the module was submerged for 24 hours.

[0060] Please see Figure 5 and Figure 7 The lead-out cover is made of layered composite material, with PET as the base material and a thickness of 0.2mm. A fluoropolymer film, made of PTFE (polytetrafluoroethylene) and 25μm thick, is fixed to the air-facing side via a hot-melt bonding process. This film exhibits excellent weather resistance and anti-aging properties, and can withstand high and low temperature cycles from -40℃ to 85℃. An EVA layer, 200μm thick, with a melt flow index of [missing information], is fixed to the module-facing side via a coating process. It is tightly bonded to the back panel through a lamination process, with a bonding strength ≥1.8N / mm.

[0061] The positive and negative openings on the lead-out cover are processed using laser drilling, with a diameter of 5mm. Their positions precisely correspond to the lead-out positions of the positive and negative busbars, with a deviation of ≤±0.2mm. The edges of the openings are polished to remove burrs and prevent damage to the leads. The positive busbar leads out from the positive opening, and the negative busbar leads out from the negative opening. The leads are made of tin-plated copper core wire with a diameter of [missing information]. The outer layer is wrapped with fluoroplastic insulation. The positive and negative leads are connected to the corresponding electrodes of the integrated junction box through a crimping process with a crimping pressure of 5-8MPa and a contact resistance of ≤5mΩ. This ultimately achieves dual-line lead-out of the four-terminal component, simplifying the power station circuit design and inverter configuration.

[0062] Example 2

[0063] like Figure 7 As shown in the figure, this embodiment also discloses a packaging method for a perovskite-TOPCon four-terminal tandem solar cell flexible module. This method is used to prepare the above-mentioned perovskite-TOPCon four-terminal tandem solar cell flexible module structure, and specifically includes the following steps:

[0064] S1. Integrated Front Panel Preparation: First, a 120μm thick PET film is selected as the polymer plastic film substrate. Its outer surface is activated using a plasma surface treatment process to improve coating adhesion. The treatment power is 100-150W, and the treatment time is 5-10 minutes. Then, the substrate is placed in a vacuum coating machine, and deposition is performed using vacuum deposition technology. Control the vacuum level to The deposition rate is 0.8 nm / s, the coating thickness is 100 nm, forming a dense coating without pinholes, and obtaining a high water-resistant and oxygen-barrier material.

[0065] Next, an acrylic resin adhesive layer with a thickness of 10μm is uniformly coated on the surface of the dense coating using a roller coater. Immediately after coating, a 25μm thick PVDF UV-blocking film is tightly bonded to the adhesive layer and sent into a hot press for lamination. The hot pressing temperature is 85℃, the pressure is 0.3MPa, and the holding time is 12 minutes to ensure that the two are firmly bonded together.

[0066] The composite film is then pretreated by applying an acrylic release tape with a width of 35mm at a fixed length along the width of the composite film. This tape corresponds to the sealing and bonding surface in the width direction of the component. The same type of release tape with a width of 18mm is applied along the length direction of the roll material, corresponding to the sealing and bonding surface in the length direction of the component. The bonding strength between the tape and the composite film is ≥1.0N / mm, and it does not affect the flexibility of the component.

[0067] Finally, the composite film is fed into a roll-to-roll magnetron sputtering system to prepare an ITO conductive film on the inner side of the composite film substrate. The sputtering power is 300-400W, the argon flow rate is 50-80 sccm, and the sheet resistance of the prepared ITO conductive film is [value missing]. With a visible light transmittance of ≥85%, after preparation, the substrate is coated and rolled up to obtain an integrated front panel substrate.

[0068] S2. Fabrication of perovskite top cell: On the ITO conductive film of the integrated front panel substrate, each functional layer is fabricated in the following structural order: transparent conductive electrode, hole transport layer, perovskite light-absorbing layer, electron transport layer, and metal electrode.

[0069] The transparent conductive electrode directly utilizes an ITO conductive film; the hole transport layer is Spiro-OMeTAD, prepared via a solution spin-coating process at a spin speed of 3000-4000 rpm for 30 seconds, followed by annealing at 100°C for 10 minutes, resulting in a film thickness of 200-300 nm; the perovskite light-absorbing layer is selected from... It was prepared using a two-step spin coating method. The first step was spin coating. The first step involves spin-coating the solution at 2000-3000 rpm for 20 seconds. The second step involves spin-coating the CH3NH3I solution at 4000-5000 rpm for 30 seconds, followed by annealing at 70°C for 30 minutes, resulting in a film thickness of 500-800 nm. The electron transport layer is selected from [specific materials / processes]. The coating was prepared by sol-gel method, and after coating, it was annealed at 500℃ for 30 minutes, with a film thickness of 50-100nm; the metal electrode was silver, which was prepared by vacuum thermal evaporation process with an evaporation rate of 0.1-0.2nm / s and a film thickness of 100-200nm.

[0070] Please see Figure 3 During the fabrication process, P1, P2, and P3 etching were performed sequentially using a nanosecond laser etching device with a laser wavelength of 532 nm, a power of 5-10 W, and a scanning speed of [missing information]. ;

[0071] The P1 etching spacing is determined to be 5mm based on the module design current requirements, controlling the area of ​​the perovskite cell to be 15cm², and the etching gap width to be 2mm, to adapt to subsequent module cutting and processing.

[0072] The etching depths of P2 and P3 are controlled at 350nm and 300nm respectively to ensure that adjacent functional layers are not damaged.

[0073] After etching, the insulating tape applied during the pretreatment stage was removed using a mechanical peeling process, resulting in an integrated front-panel perovskite top cell. Testing showed its open-circuit voltage to be 1.1V and its short-circuit current density to be... .

[0074] S3, Module Stacking: On the metal electrode side of the perovskite top cell, the first adhesive film is laid flat using an automated laying equipment, with a laying deviation of ≤±0.5mm; the TOPCon bottom cell is attached to the side of the first adhesive film away from the top cell, and the bottom cell and top cell are precisely aligned using a visual positioning system, with an edge deviation of ≤±0.3mm.

[0075] On the side of the TOPCon bottom cell away from the top cell, a second adhesive film, a glass fiber cloth, and another second adhesive film are laid flat in sequence to form a composite adhesive layer. The second adhesive film has the same specifications as the first adhesive film, and the glass fiber cloth has a thickness of 40μm.

[0076] Next, attach the transparent water-blocking backsheet to the side of the composite adhesive layer away from the bottom cell. Apply 0.1MPa of pressure using a pre-pressing device for initial fixation. The pre-pressing time is 5 minutes to complete the module stacking. After stacking, the overall thickness of the module is controlled between 1.5-2.0mm.

[0077] S4. Circuit Connection: A fully parallel circuit is constructed using flat tin-plated copper busbars. The positive busbars of the top battery and the bottom battery are fixedly connected using ultrasonic welding equipment at a temperature of 190℃ and a welding time of 0.8s to form a positive busbar group. The negative busbars of the top battery and the bottom battery are fixedly connected using the same process to form a negative busbar group.

[0078] In the area where the busbar contacts the battery cell, apply a 15mm wide polyimide insulating tape, ensuring that the insulating tape completely covers the contact area and extends 2mm beyond the busbar at the edge.

[0079] The distance between the lead-out positions of the top and bottom batteries is measured using a digital display rangefinder to ensure it is 10.4mm, which meets the creepage distance requirement. If the distance does not meet the standard, it is corrected by fine-tuning the position of the busbar.

[0080] S5. Sealing and cover plate installation: Apply hot melt butyl adhesive continuously along the four edges of the component using an automatic glue applicator at a speed of 10mm / s to form a circumferential sealing strip with a width of 10mm and a thickness of 1.2mm, ensuring that the sealing strip is free of breaks and air bubbles.

[0081] At the lead-out points of the positive and negative busbars, an additional 10mm wide and 1.2mm thick butyl rubber is applied using a dispensing machine to seal the lead-out ends.

[0082] With the EVA layer of the lead-out cover facing the backplate, use a visual positioning fixture to align and cover the positive and negative lead-out positions, ensuring that the positive busbar group accurately corresponds to the positive opening of the lead-out cover and the negative busbar group accurately corresponds to the negative opening, with a positioning deviation of ≤±0.2mm; then apply a pressure of 0.2MPa using a pressing device to initially fix the lead-out cover onto the backplate, with a pressing time of 3 minutes.

[0083] S6, Lamination: The stacked and sealed components with cover plates installed are placed into a laminator with a vacuum heating chamber and a cooling chamber;

[0084] First, the component is placed into the vacuum heating chamber. After closing the chamber door, a vacuum is evacuated until the vacuum level is ≥ 1. At the same time, heat to 100℃ at a heating rate of 2℃ / min and keep warm for 30 minutes to remove air from the component and fully soften the EVA adhesive layer and butyl adhesive to ensure that the structure of each layer is fully bonded.

[0085] Subsequently The pressure gradient is applied to 0.4 MPa and maintained for 20 minutes to ensure tight bonding of each layer. The module is then placed in a cooling chamber and cooled to room temperature at a rate of 1 °C / min to prevent internal stress deformation due to excessive cooling.

[0086] After cooling, open the cavity door and remove the component. Remove excess butyl rubber and adhesive film from the edges by mechanical peeling. Lead out the positive electrode busbar from the positive electrode opening, cut it to a length of 15cm, and peel off the 5mm insulation layer at the end to form the positive electrode lead wire.

[0087] Lead the negative busbar from the negative opening and process it in the same way to form the negative lead wire; connect the positive and negative lead wires to the corresponding electrodes of the integrated junction box using a crimping machine with a crimping pressure of 6MPa. After connection, perform a continuity test to ensure good contact.

[0088] Finally, the components undergo appearance inspection, sealing inspection, and electrical performance testing. Once the tests are passed, the components are encapsulated.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flexible module structure for a perovskite-TOPCon four-terminal stacked solar cell, characterized in that, It includes an integrated front panel perovskite top cell, TOPCon bottom cell, adhesive layer, backplane, circuit components, sealing structure, and lead wire cover. The integrated front panel perovskite top cell consists of, from the outside to the inside, an ultraviolet cutoff film layer, an adhesive layer, a dense metal oxide coating layer, a polymer plastic film substrate, an ITO conductive film layer, and a perovskite cell layer. The dense metal oxide coating layer is prepared by vacuum deposition technology, and the ultraviolet cutoff film layer and the dense metal oxide coating layer are composited by an adhesive layer. The adhesive layer includes a first adhesive film and a composite adhesive structure. The first adhesive film is sandwiched between the top battery and the bottom battery. The composite adhesive structure is composed of a second adhesive film, a fiber cloth, and a second adhesive film. The composite adhesive structure is used to bond the bottom battery to the backsheet. The backsheet has water-blocking and oxygen-barrier functions. The circuit assembly is a fully parallel structure, including a busbar group and an insulating strip. The busbar group is divided into a positive busbar group and a negative busbar group, which are respectively connected to the positive and negative terminals of the top battery and the bottom battery. The top and bottom battery leads are staggered and meet the creepage distance. The insulating strip is located between the busbar and the battery cell. The sealing structure is butyl rubber, which is laid all around the perimeter of the component and additionally laid at the outlet of the busbar group; The lead-out cover is made of composite material, with a fluorine film bonded to the air surface and EVA coated on the component surface. The EVA surface is laminated and bonded to the back sheet. The positive and negative busbar groups are led out from the corresponding openings of the lead-out cover and connected to the integrated junction box to achieve dual-line lead-out.

2. The perovskite-TOPCon four-terminal tandem flexible module structure according to claim 1, characterized in that, The polymer plastic film substrate is any one of PET, PEN, or PI, and the dense metal oxide coating is... or Any one of the following, wherein the dense metal oxide coating is free of pinhole defects, ensuring water and oxygen barrier effects.

3. The perovskite-TOPCon four-terminal tandem flexible module structure according to claim 1, characterized in that, The ultraviolet blocking film layer is any one of PVDF, ETFE or modified PET, which can specifically block short-wavelength UVA and UVC light without affecting the transmission of visible light. The adhesive layer is an acrylic resin adhesive layer, which is used to achieve a firm composite between the ultraviolet blocking film layer and the dense metal oxide coating.

4. The perovskite-TOPCon four-terminal tandem flexible module structure according to claim 1, characterized in that, The backsheet is a transparent water-blocking backsheet, allowing sunlight to reach the back of the bottom cell. The back absorbs light, thus increasing the module's power. The water-blocking and oxygen-barrier properties of the backsheet work synergistically with the dense metal oxide coating to enhance the overall protection of the module.

5. The flexible module structure of a perovskite-TOPCon four-terminal stacked solar cell according to claim 1, characterized in that, The fabrication process of the perovskite solar cell layer includes P1 etching, P2 etching and P3 etching in sequence; P1 etching occurs in the ITO conductive film layer, which is used to divide the large-area ITO conductive film into multiple independent battery cell conductive regions. P2 etching occurs between the perovskite layer and the hole transport layer to achieve hole transport layer isolation between adjacent cell units; P3 etching occurs between the electron transport layer and the metal electrode to isolate the electron transport layer from the metal electrode of adjacent cell cells.

6. A method for encapsulating a flexible perovskite-TOPCon four-terminal tandem solar cell module, comprising the structure of a flexible perovskite-TOPCon four-terminal tandem solar cell module according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Integrated front panel preparation: First, a polymer plastic film is selected as the substrate. Metal oxides are deposited on its outer surface using vacuum deposition technology to form a dense coating without pinholes, obtaining a high water-resistant and oxygen-barrier material. Then, an adhesive layer is uniformly coated on the surface of the dense coating. The UV cut-off film is bonded to the adhesive layer and a composite film is formed through a composite process. The composite film is then pretreated. Adhesive tape is applied along the width direction and the length direction of the roll of the composite film to form the component sealing and bonding surface. Finally, an ITO conductive film is prepared on the inner side of the composite film substrate using roll-to-roll magnetron sputtering technology. After preparation, the film is coated and rolled up to obtain the integrated front panel substrate. S2. Fabrication of perovskite top cell: On the ITO conductive film of the integrated front panel substrate, each functional layer is fabricated in sequence according to the structure of transparent conductive electrode, hole transport layer, perovskite light-absorbing layer, electron transport layer and metal electrode. During the process, P1 etching, P2 etching and P3 etching are completed in sequence. After etching, the isolation tape applied in the pretreatment stage is removed to obtain the integrated front panel perovskite top cell. S3, Module Stacking: A first adhesive film is laid flat on the metal electrode side of the perovskite top cell. The TOPCon bottom cell is then attached to the side of the first adhesive film away from the top cell, ensuring that the bottom cell and the top cell are aligned. On the side of the TOPCon bottom cell away from the top cell, a second adhesive film, a fiber cloth, and another second adhesive film are laid flat in sequence to form a composite adhesive layer. The backsheet is then attached to the side of the composite adhesive layer away from the bottom cell to complete the module stacking. S4. Circuit connection: A fully parallel circuit is constructed using busbars. The positive busbar of the top battery is fixedly connected to the positive busbar of the bottom battery to form a positive busbar group. The negative busbar of the top battery is fixedly connected to the negative busbar of the bottom battery to form a negative busbar group. An insulating strip is set in the contact area between the busbar and the battery cell to ensure that the distance between the lead-out positions of the top battery and the bottom battery meets the creepage distance requirements. S5. Sealing and cover plate installation: Apply butyl rubber continuously along the four edges of the component to form a circumferential seal. Apply additional butyl rubber at the lead-out positions of the positive and negative busbar groups to form a lead-out end seal. With the EVA layer of the lead-out cover plate facing the back plate, align and cover the positive and negative lead-out positions, ensuring that the positive busbar group corresponds to the positive opening of the lead-out cover plate and the negative busbar group corresponds to the negative opening of the lead-out cover plate. S6. Lamination Molding: The stacked and sealed components with cover plates installed are placed in a laminator with a vacuum heating chamber and a cooling chamber. First, a vacuum is drawn and heated in the vacuum heating chamber to ensure that the layers are fully bonded. Then, pressure is applied to ensure that the layers are firmly bonded. Finally, the components are sent to the cooling chamber to cool to room temperature to complete the component molding. The positive electrode busbar is led out from the positive electrode opening to form the positive electrode lead wire, and the negative electrode busbar is led out from the negative electrode opening to form the negative electrode lead wire. The positive and negative electrode leads wires are connected to the corresponding electrodes of the integrated junction box to realize the dual-wire lead wire of the four-terminal component.

7. The perovskite-TOPCon four-terminal tandem flexible module structure and encapsulation method according to claim 6, characterized in that, In step S1, during the pretreatment of the composite film, the tape applied along the width direction of the composite film corresponds to the sealing and bonding surface in the width direction of the component, and the tape applied along the length direction of the roll corresponds to the sealing and bonding surface in the length direction of the component. The bonding strength between the tape and the composite film meets the bonding requirements in the subsequent encapsulation process and does not affect the flexibility of the component.

8. The perovskite-TOPCon four-terminal tandem solar cell flexible module structure and encapsulation method according to claim 6, characterized in that, In step S2, the spacing of P1 etching is determined according to the current requirements of the module design to control the area of ​​the perovskite cell. The gap width of P1 etching is determined according to the overall size of the module to adapt to the subsequent module cutting and processing requirements. The depths of P2 etching and P3 etching are controlled between corresponding layers to ensure that adjacent functional layers are not damaged.

9. The perovskite-TOPCon four-terminal tandem flexible module structure and encapsulation method according to claim 6, characterized in that, In step S5, the lead-out cover plate uses PET as the substrate, the fluoropolymer film is fixed to the air surface of the substrate by an adhesive process, and the EVA layer is fixed to the component surface of the substrate by a coating process. The positions of the positive and negative openings of the lead-out cover plate correspond precisely to the lead-out positions of the positive and negative busbar groups.

10. The perovskite-TOPCon four-terminal tandem solar cell flexible module structure and encapsulation method according to claim 6, characterized in that, In step S6, during the lamination process, the purpose of vacuum heating is to remove air from the inside of the component and soften the adhesive layer, the purpose of pressure treatment is to make the structure of each layer tightly bonded, and the purpose of cooling treatment is to shape the component and maintain structural stability.

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