A composite flexible solar cell and a method for manufacturing the same

Abstract

This invention discloses a composite flexible solar cell and its fabrication method. The cell assembly comprises, from bottom to top, a rigid substrate, an adhesive film layer, and a flexible solar cell layer. An elastomer protective layer is also attached to the upper surface of the composite flexible solar cell. The thickness of the rigid substrate is less than 500 μm. The fabrication method includes: (1) setting an adhesive film layer on the surface of the rigid substrate; (2) arranging flexible solar cells on the surface of the adhesive film layer; (3) connecting the positive and negative electrodes of the flexible solar cell using electrode output lines; and (4) attaching the elastomer protective layer to the upper surface of the intermediate product and forming it by vacuum hot pressing. The composite flexible solar cell of this invention combines flexibility (low bending radius), mechanical strength (deformation resistance, long-term reliability), and weather resistance. Compared with the traditional roll-to-roll process for flexible substrates, it has higher production efficiency and better product quality.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a flexible solar cell with a composite structure that possesses high mechanical strength and a small bending radius, and a method for its fabrication. Background Technology

[0002] Flexible solar cells, due to their lightweight, bendability, and ease of integration, have shown great application potential in building-integrated photovoltaics, wearable devices, and mobile energy. Currently, mainstream technologies typically use polymers, metal foils, or ultra-thin glass as flexible substrates, combined with perovskite, organic, or CIGS thin-film cells, and encapsulated through roll-to-roll lamination or vacuum hot-pressing processes. However, the structural strength of the flexible substrates used in existing technologies is relatively poor, failing to provide effective mechanical support for the cell modules. Therefore, the resulting cell modules exhibit certain deficiencies in deformation resistance, long-term reliability, and weather resistance. Furthermore, production can only be achieved using flexible roll-to-roll processes, and the production efficiency cannot fully meet market demands. These structural and technological shortcomings limit and constrain the development and application scenarios of flexible electrodes. Summary of the Invention

[0003] This invention provides a composite flexible solar cell and its preparation method, which solves the technical problems mentioned in the background art, such as poor structural strength and low production efficiency of existing flexible solar cells.

[0004] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A composite flexible solar cell comprises, from bottom to top, a rigid substrate, an adhesive film layer, and a flexible solar cell layer, wherein an elastomer protective layer is also attached to the upper surface of the composite flexible solar cell; the thickness of the rigid substrate is less than 500 μm.

[0005] The design concept of the above technical solution lies in the fact that the present invention adopts a synergistic design of materials and structure, and uses an innovative composite structure, namely a combination of "rigid substrate + flexible battery + elastomer protective film". The rigid substrate is combined with the flexible battery and protected by an elastomer protective film layer on the outer layer. When the thickness of the rigid substrate is reduced to the extremely thin thickness range defined by the present invention, it will exhibit a certain degree of flexibility while retaining its mechanical properties. Therefore, the combination of the rigid substrate and the flexible battery forms a "rigid-flexible coupling" interface, which ensures high mechanical strength during battery life while achieving a low bending radius of curvature, significantly enhancing the deformation resistance and long-term reliability of the component. At the same time, the elastomer protective film layer attached to the surface of the battery device can fill the micro gaps in the flexible battery layer with its high-temperature fluidity, which not only enhances the interface bonding force, but also absorbs bending stress and external impact through elastic deformation, and improves weather resistance.

[0006] As a further preferred embodiment of the above technical solution, the rigid substrate includes any one of glass fiber board, carbon fiber board, quartz fiber board, and resin plywood. The rigid substrate is preferably a glass fiber board or carbon fiber board with a thickness of less than 500 micrometers, whose tensile modulus (approximately 70 GPa for glass fiber and approximately 230 GPa for carbon fiber) is much higher than that of traditional plastic boards (approximately 3.0 GPa), providing metal-like mechanical support, effectively resisting external deformation stress, and preventing the battery layer from failing due to substrate deformation.

[0007] As a further preferred embodiment of the above technical solution, the adhesive film layer is a hot-melt adhesive film layer, which includes any one of polyolefin elastomer, ethylene-vinyl acetate copolymer, polyurethane, and polyimide. The hot-melt material used as an adhesive between the rigid substrate and the flexible solar cell layer is crucial. This material not only acts as an adhesive but also fills gaps, prevents voids, relieves stress, and prevents material fatigue or damage.

[0008] As a further preferred embodiment of the above technical solution, the thickness of the adhesive film layer is less than 200 μm.

[0009] As a further preferred embodiment of the above technical solution, the elastomer protective film includes any one of polyethylene phthalate, thermoplastic polyurethane, polyolefin elastomer, and ethylene-vinyl acetate copolymer.

[0010] As a further preferred embodiment of the above technical solution, the thickness of the elastomeric protective film is less than 300 μm, and the light transmittance is greater than 80%. In the design process of the elastomeric protective film, the primary focus is on the material's high light transmittance, as this ensures that the photoelectric conversion efficiency is not impaired by the elastomeric protective film. Secondly, considering that the quality of UV resistance directly determines whether the elastomeric protective film will yellow under long-term UV irradiation and directly affects the stability of light transmittance, the aforementioned material with excellent UV resistance was specifically selected. Furthermore, the aforementioned elastomeric material was chosen as the protective film because it can meet the deformation requirements during flexible bending and can also play a role in absorption and buffering, thereby effectively protecting the flexible solar cell in the middle and preventing it from breaking due to impact.

[0011] As a further preferred embodiment of the above technical solution, the composite flexible solar cell has a thickness of less than 800 micrometers and a bending radius of less than 20 mm.

[0012] As a further preferred embodiment of the above technical solution, the flexible solar cell layer includes any one of perovskite solar cells, organic solar cells, perovskite / perovskite tandem solar cells, and perovskite / organic tandem solar cells.

[0013] Based on the same technical concept, the present invention also provides a method for preparing the composite flexible solar cell described above, comprising the following steps: (1) An adhesive film layer is formed on the surface of the rigid substrate; (2) Arrange flexible solar cells on the surface of the adhesive film layer to form a flexible solar cell layer; (3) Connect the positive and negative electrodes of the flexible solar cell using electrode output lines to obtain intermediate products; (4) The elastomer protective layer is attached to the upper surface of the intermediate product and vacuum hot-pressed to form the composite flexible solar cell.

[0014] Through a unique structural design, the rigid substrate in the battery device enables the device to meet the production requirements of the vacuum hot pressing process. Compared with the traditional roll-to-roll process for flexible devices, the vacuum hot pressing process undoubtedly has higher production efficiency and higher yield when encapsulating large-area modules, which can effectively reduce the production cost of flexible solar cells and improve economic benefits.

[0015] As a further preferred embodiment of the above technical solution, in step (3), the electrode output line is connected to the flexible solar cell by welding or conductive adhesive, and the welding material is selected from gold, silver, copper, tungsten and their alloys.

[0016] As a further preferred embodiment of the above technical solution, in step (4), during the vacuum hot pressing molding process, the vacuum degree is ≤0.1MPa, the temperature is 80~150℃, and the molding time is 10~20min. Perovskite solar cells are organic-inorganic materials. Excessive temperature and excessively long molding time will cause the material to decompose and lose its photoelectric conversion efficiency.

[0017] The present invention has the following beneficial effects: (1) The composite flexible solar cell of the present invention breaks through the limitation of "either rigid or flexible" in traditional material design. It adopts the synergistic design of materials and structure to obtain a unique structure of "rigid substrate + flexible cell + elastomer protective film", which makes the battery device flexible (low bending radius) and mechanical strength (deformation resistance, long-term reliability) and weather resistance, meeting the application standards of consumer photovoltaic products. Moreover, it surpasses the organic photovoltaic (OPV) and copper indium gallium selenide (CIGS) technology products on the current market in terms of performance. (2) The composite flexible solar cell of the present invention is produced by vacuum hot pressing bonding process, which has higher production efficiency and better product quality compared with the traditional roll-to-roll process of flexible substrate. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the composite flexible solar cell of Example 1.

[0019] Figure 2 This is a physical image of the composite flexible solar cell module of Example 1.

[0020] Figure 3 This is a schematic diagram of the electrode of the flexible solar cell connected by the electrode output line in step (3) of the preparation method. Detailed Implementation

[0021] The present invention will be described in detail below with reference to embodiments and accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0022] Example 1: like Figure 1-2 As shown, the composite flexible solar cell of this embodiment includes, from bottom to top, a rigid glass fiber substrate (200 μm thick, 10 mm bending radius), a hot-melt polyolefin elastomer (POE) film layer (100 μm thick), and a perovskite flexible solar cell layer. The upper surface of the composite flexible solar cell is also covered with a thermoplastic polyurethane (TPU) elastomer protective layer (88% light transmittance, 150 μm thick).

[0023] The composite flexible solar cell of this embodiment is prepared by the following method: (1) After rinsing the hard substrate with high pressure water and ultrasonically cleaning it in IPA solvent, the substrate is dried. A hot melt film polyolefin elastomer (POE) with a thickness of 100.0 μm is coated on the surface of the dried hard substrate.

[0024] (2) At room temperature, three perovskite flexible solar cells are arranged in a 1*3 matrix on a hot melt adhesive film.

[0025] (3) such as Figure 3 As shown, the positive and negative electrodes of the perovskite flexible solar cell are connected to the electrode output lines (positive and negative output lines) of the module by welding gold wires to obtain an intermediate product.

[0026] (4) A thermoplastic polyurethane (TPU) elastomer protective film with a thickness of 150.0 μm and a light transmittance of 88.0% is bonded to the surface of the intermediate product and formed by vacuum hot pressing. During the forming process, the vacuum degree is maintained at 0.1 MPa, the temperature is controlled at 100.0℃, and the forming time is 10 min, thus obtaining the composite flexible solar cell of this embodiment.

[0027] The composite flexible solar cell module of this embodiment was tested. The module's thickness was less than 620.0 μm, its bending radius was less than 15.0 mm, and after being repeatedly bent 1000 times, its photoelectric conversion efficiency remained above 94.9%. A 100-gram steel ball was dropped freely from a height of 1 meter onto the perovskite solar cell area of ​​the composite flexible solar cell module. After three repeated drops, the module remained undamaged. In contrast, solar cell modules without a thermoplastic polyurethane (TPU) elastomer protective layer failed to function properly.

[0028] Example 2: The composite flexible solar cell of this embodiment includes, from bottom to top, a carbon fiber rigid substrate (thickness of 500 μm and bending radius of 20 mm), a hot-melt ethylene-vinyl acetate copolymer (EVA) film layer (thickness of 200 μm), and an organic flexible solar cell layer. The upper surface of the composite flexible solar cell is also covered with a polyolefin elastomer (POE) elastomer protective layer (transmittance of 80% and thickness of 100 μm).

[0029] The composite flexible solar cell of this embodiment is prepared by the following method: (1) After rinsing the hard substrate with high pressure water and ultrasonically cleaning it in IPA solvent, the substrate is dried. A 200.0 μm thick hot melt ethylene-vinyl acetate copolymer (EVA) is then coated on the surface of the dried hard substrate.

[0030] (2) At room temperature, nine organic flexible solar cells are arranged in a 3*3 matrix on a hot melt adhesive film.

[0031] (3) Connect the positive and negative electrodes of the organic flexible solar cell to the electrode output lines (positive output line and negative output line) of the module by welding gold wire to obtain an intermediate product.

[0032] (4) A polyolefin elastomer (POE) protective film with a thickness of 100.0 μm and a light transmittance of 80.0% is bonded to the surface of the intermediate product and formed by vacuum hot pressing. During the forming process, the vacuum degree is maintained at 0.08 MPa, the temperature is controlled at 80.0℃, and the forming time is 15 min, thus obtaining the composite flexible solar cell of this embodiment.

[0033] The composite flexible solar cell module of this embodiment was tested. The module's thickness was less than 780.0 μm, its bending radius was less than 20.0 mm, and after 1000 repeated bending cycles, its photoelectric conversion efficiency remained above 96.2%. A 100-gram steel ball was dropped freely from a height of 1 meter onto the perovskite solar cell area of ​​the composite flexible solar cell module; after three repeated drops, it remained undamaged. In contrast, solar cell modules without a polyolefin elastomer (POE) elastomer protective layer failed to function properly.

[0034] Example 3: The composite flexible solar cell of this embodiment includes, from bottom to top, a rigid quartz fiberboard substrate (thickness of 300 μm and bending radius of 17 mm), a hot-melt polyurethane (PU) film layer (thickness of 80 μm), and a perovskite / organic tandem flexible solar cell layer. The upper surface of the composite flexible solar cell is also covered with a polyethylene terephthalate (PET) elastomer protective layer (transmittance of 84% and thickness of 300 μm).

[0035] The composite flexible solar cell of this embodiment is prepared by the following method: (1) After rinsing the hard substrate with high pressure water and ultrasonically cleaning it in IPA solvent, dry it and coat the surface of the dried hard substrate with a hot melt polyurethane (PU) with a thickness of 80.0 μm.

[0036] (2) At room temperature, nine perovskite / organic tandem flexible solar cells are arranged in a 3*3 matrix on a hot melt adhesive film.

[0037] (3) Connect the positive and negative electrodes of the perovskite / organic tandem flexible solar cell to the electrode output lines (positive output line and negative output line) of the module by welding gold wire to obtain an intermediate product.

[0038] (4) A polyethylene terephthalate (PET) elastomer protective film with a thickness of 300.0 μm and a light transmittance of 84.0% is bonded to the surface of the intermediate product and formed by vacuum hot pressing. During the forming process, the vacuum degree is maintained at 0.1 MPa, the temperature is controlled at 150.0℃, and the forming time is 20 min, thus obtaining the composite flexible solar cell of this embodiment.

[0039] The composite flexible solar cell module of this embodiment was tested. The module's thickness was less than 710.0 μm, its bending radius was less than 16.0 mm, and after being repeatedly bent 1000 times, its photoelectric conversion efficiency remained above 95.1%. A 100-gram steel ball was dropped freely from a height of 1 meter onto the perovskite solar cell area of ​​the composite flexible solar cell module. After three repeated drops, the module remained undamaged. In contrast, the solar cell module without a polyethylene terephthalate (PET) elastomer protective film failed to function properly.

[0040] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. For those skilled in the art, improvements and modifications obtained without departing from the inventive concept should also be considered within the scope of protection of the present invention.

[0041] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A composite flexible solar cell, characterized in that, From bottom to top, the composite flexible solar cell comprises a rigid substrate, an adhesive film layer, and a flexible solar cell layer. The upper surface of the composite flexible solar cell is also covered with an elastomer protective layer. The thickness of the rigid substrate is less than 500 μm.

2. The composite flexible solar cell according to claim 1, characterized in that, The rigid substrate includes any one of glass fiber board, carbon fiber board, quartz fiber board and resin plywood.

3. The composite flexible solar cell according to claim 1, characterized in that, The adhesive film layer is a hot-melt adhesive film layer, which includes any one of polyolefin elastomer, ethylene-vinyl acetate copolymer, polyurethane and polyimide.

4. The composite flexible solar cell according to claim 3, characterized in that, The thickness of the adhesive film layer is less than 200 μm.

5. The composite flexible solar cell according to claim 1, characterized in that, The elastomeric protective film includes any one of polyethylene phthalate, thermoplastic polyurethane, polyolefin elastomer, and ethylene-vinyl acetate copolymer.

6. The composite flexible solar cell according to claim 5, characterized in that, The thickness of the elastomer protective film is less than 300 μm, and the light transmittance is greater than 80%.

7. The composite flexible solar cell according to any one of claims 1-6, characterized in that, The composite flexible solar cell has a thickness of less than 800 micrometers and a bending radius of less than 20 mm.

8. A method for preparing a composite flexible solar cell according to any one of claims 1-7, characterized in that, Includes the following steps: (1) An adhesive film layer is formed on the surface of the rigid substrate; (2) Arrange flexible solar cells on the surface of the adhesive film layer to form a flexible solar cell layer; (3) Connect the positive and negative electrodes of the flexible solar cell using electrode output lines to obtain intermediate products; (4) The elastomer protective layer is attached to the upper surface of the intermediate product and vacuum hot-pressed to form the composite flexible solar cell.

9. The method for preparing a composite flexible solar cell according to claim 8, characterized in that, In step (3), the electrode output line is connected to the flexible solar cell by welding or conductive adhesive, and the welding material is selected from gold, silver, copper, tungsten and their alloys.

10. The method for preparing a composite flexible solar cell according to claim 8, characterized in that, In step (4), during the vacuum hot pressing molding process, the vacuum degree is ≤0.1MPa, the temperature is 80~150℃, and the molding time is 10~20min.

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