Photovoltaic composite material and preparation method and application thereof

Abstract

The invention belongs to the technical field of photovoltaic textile compounding, and provides a photovoltaic composite material and a preparation method and application thereof. The photovoltaic composite material comprises a flexible conductive textile substrate, an integrated membrane material and a transparent protective layer which are integrally formed through hot pressing, the flexible conductive textile substrate is a conductive network woven by warp yarns and weft yarns, and the warp yarns and / or the weft yarns are conductive yarns; the integrated film material comprises a lower packaging film, a photovoltaic adhesive film and an upper packaging film which are formed by co-extrusion; the photovoltaic adhesive film material comprises a base material and an optical active substance, the lower packaging film and the upper packaging film are made of thermoplastic packaging materials which are the same as and / or compatible with the base material; the upper packaging film and the lower packaging film make contact with and package the transparent protection layer and the flexible conductive textile substrate respectively, and the photovoltaic adhesive film permeates into the flexible conductive textile substrate through hot pressing and makes ohmic contact with the conductive network. The photovoltaic composite material has the advantages of good flexibility, stable photoelectric conversion efficiency, good durability, firm combination with a conductive network and the like, and can be applied to various flexible products for power supply.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photovoltaic textile composite technology, in particular to a photovoltaic composite material and a preparation method and application thereof. BACKGROUND

[0002] With the development of cross and mutual benefit of multiple technical fields in the industry, the combination of photovoltaic technology and textile technology has gradually become a research hotspot. There are currently several technical paths for the combination of photovoltaic technology and textile technology:

[0003] 1. Fiber-like solar cell weaving technology: solar cells are made into fiber-like and directly woven into textiles. For example, the Powerweave European research team developed a solar photovoltaic cell technology based on dye-sensitized fiber materials, which realizes the dual functions of flexible solar photovoltaic power generation and storage textiles through knitting or weaving. This technology faces problems such as easy breakage of photovoltaic fibers, low photoelectric conversion efficiency (usually less than 1%), and easy short circuit during weaving process. The weaving process is complex and difficult to scale.

[0004] 2. Coating treatment technology: coating a photovoltaic material layer on the surface of the fabric. Researchers from the Fraunhofer Institute in Germany applied conductive polyester fiber electrodes and photovoltaic layers to glass fiber fabric through transfer printing. However, the photoelectric conversion efficiency of the photovoltaic layer prepared by this method is only between 0.1-0.3%, and the coating has poor adhesion to the fabric and insufficient washing resistance. This technology often requires special fabric substrates (such as glass fibers).

[0005] 3. External attachment technology: attaching flexible solar cell components to the surface of the fabric. For example, the "flexible solar cell component" developed by Wuhan Textile University connects several solar cell pieces with flexible bottom materials such as textile fabric. However, this technology has problems such as insufficient flexibility, affecting the original mechanical properties and comfort of the textile, and the connection between the battery pieces is prone to failure under repeated bending.

[0006] In addition, the publication CN119953068A discloses a fabric treatment device for thin-film photovoltaic coating attachment, which reduces the occurrence of wrinkles caused by the rebound of chemical fiber fabric through a lamination piece and a smoothing assembly, but does not solve the problem of interface adhesion decay of the photovoltaic layer and the fabric during long-term use.

[0007] Therefore, there is an urgent need to develop a new photovoltaic composite material that has good flexibility, high and stable photoelectric conversion efficiency, good durability, and firm combination with the textile, as well as a preparation method thereof. SUMMARY

[0008] The present application aims at solving the problems of the prior art, and provides a photovoltaic composite material, a preparation method and application thereof by combining photovoltaic technology with textile technology.

[0009] Based on this, the present application discloses a photovoltaic composite material, which comprises a flexible conductive textile substrate, an integrated film material and a transparent protective layer which are sequentially stacked and integrally formed by hot pressing.

[0010] The flexible conductive textile substrate is a conductive network formed by interweaving warp yarns and weft yarns, and the warp yarns and / or weft yarns are conductive yarns.

[0011] The integrated film material comprises a lower encapsulation film, a photovoltaic adhesive film and an upper encapsulation film which are sequentially stacked and integrally formed by co-extrusion; the material used for the photovoltaic adhesive film comprises a base material and a photoactive substance dispersed in the base material; the material used for the lower encapsulation film and the upper encapsulation film is a thermoplastic encapsulation material which is the same as and / or compatible with the base material of the photovoltaic adhesive film.

[0012] The lower encapsulation film contacts and encapsulates the flexible conductive textile substrate, and the upper encapsulation film contacts and encapsulates the transparent protective layer, while the photovoltaic adhesive film penetrates into the flexible conductive textile substrate during the process of integrally forming by hot pressing to form ohmic contact with the conductive network.

[0013] Preferably, the conductive yarns are at least one of silver-plated polyamide fibers, stainless steel metal fibers and conductive polymer coated fibers; the resistivity of the conductive yarns is lower than 10^-2Ω·m, and the diameter thereof is between 0.05-0.5mm.

[0014] The conductive yarns are woven into a conductive network having a plurality of parallel and / or series conductive loops in one of plain weave, twill weave and satin weave; the thickness of the flexible conductive textile substrate is 0.05-5mm.

[0015] Preferably, the base material is at least one of ethylene-vinyl acetate copolymer, polyethylene-octene copolymer and thermoplastic polyurethane.

[0016] The photoactive substance is organic photovoltaic material and / or perovskite quantum dots.

[0017] Further preferably, the mass percentage content of the photoactive substance is 5-30%, and the thickness of the photovoltaic adhesive film is 50-500μm.

[0018] More preferably, the photoactive substance takes organic photovoltaic material as the main active material, and introduces perovskite quantum dots as a performance enhancer.

[0019] The mass percentage content of the organic photovoltaic material is 7-14%, and the organic photovoltaic material is at least one of PM6:Y6, PM6:L8-BO;

[0020] The mass percentage content of the perovskite quantum dots is 5-10%, and the perovskite quantum dots are at least one of CsPbI3 quantum dots, CsPbI2Br quantum dots and CsPbBr3 quantum dots. The light active substance can effectively improve the photoelectric conversion efficiency by constructing a system in which the organic photovoltaic material is used as a main active material layer and the perovskite quantum dots are used as a performance enhancer.

[0021] Preferably, the materials used for the lower encapsulation film and the upper encapsulation film are at least one of ethylene-vinyl acetate copolymer, polyethylene-octene copolymer and thermoplastic polyurethane; and the thicknesses of the lower encapsulation film and the upper encapsulation film are both 50-200 mu m.

[0022] Preferably, the transparent protective layer is a transparent film material made of fluorocarbon resin and / or polyethylene terephthalate, preferably a transparent film material with ultraviolet resistance and self-cleaning function; and the thickness of the transparent protective layer is 0.01-0.5 mm.

[0023] The average light transmittance of the photovoltaic composite material after hot-pressing integrated forming is not less than 75% in the visible light range.

[0024] The application also discloses a preparation method of the photovoltaic composite material, which comprises the following preparation steps:

[0025] S1, preparation of a flexible conductive textile base: using conductive yarn as warp and / or weft, a conductive network is formed by interweaving the warp and weft, and the flexible conductive textile base is obtained.

[0026] S2, preparation of an integrated film material: uniformly dispersing the light active substance in a base material to obtain a material for a photovoltaic adhesive film; melting the materials for the lower encapsulation film, the photovoltaic adhesive film and the upper encapsulation film respectively, and then preparing an integrated film material through a three-layer co-extrusion flow casting process;

[0027] S3, hot-pressing integrated forming: sequentially stacking the flexible conductive textile base, the integrated film material and the transparent protective layer, and then performing hot-pressing integrated forming, so that the lower encapsulation film melts and penetrates into the flexible conductive textile base under the action of hot pressure, the photovoltaic adhesive film forms ohmic contact with the conductive network of the flexible conductive textile base, and the lower encapsulation film and the upper encapsulation film encapsulate the whole structure by hot-pressing melting, and the photovoltaic composite material is obtained.

[0028] Preferably, in step S3, the hot-pressing temperature of the hot-pressing integrated forming is controlled to be 80-150 DEG C, the pressure is 0.5-5 MPa, and the time is 1-10 minutes.

[0029] The application further discloses an application of the photovoltaic composite material, and the photovoltaic composite material is applied to building integrated photovoltaic products, photovoltaic clothes, wearable devices, tents or curtains to provide a portable power supply.

[0030] Compared with the prior art, the application has at least the following beneficial effects:

[0031] The photovoltaic composite material of the application utilizes a flexible conductive textile substrate as an electrode, and the flexible conductive textile substrate is firmly combined with an integrated film material and a transparent protective layer (especially a photovoltaic adhesive film of the flexible conductive textile substrate and the integrated film material) through a hot-pressing integrated forming process. In this way, (1) when light transmits through the transparent protective layer and the photovoltaic adhesive film, photoactive substances in the photovoltaic adhesive film absorb photons to generate electron-hole pairs, and the electron-hole pairs are separated under the action of a built-in electric field, and the electrons are collected by a conductive network of the flexible conductive textile substrate to form an electric current; at this time, the photovoltaic adhesive film not only serves as a photoelectric conversion medium, but also serves as a bonding layer to ensure that the interface with the flexible conductive textile substrate is tightly combined, thereby avoiding the interface resistance problem in the prior art and realizing a photoelectric conversion efficiency of 7-18% of the photovoltaic composite material; and the upper encapsulating film and the lower encapsulating film on the upper and lower sides of the photovoltaic adhesive film are fused through hot pressing, thereby encapsulating the whole photovoltaic composite material, forming a whole sealing structure after the photovoltaic composite material is cooled, and isolating the photoactive substances from the external environment (water vapor and oxygen), and at the same time, ensuring that the electric current generated by the photovoltaic adhesive film can be efficiently and stably conducted to the conductive network of the flexible conductive textile substrate. (2) Moreover, the photovoltaic composite material of the application has a good photoelectric conversion efficiency retention rate (as high as more than 97%) after 10,000 bending cycles under the condition of a bending radius of 5 mm, and a power attenuation of less than 2% after 1,000 hours of irradiation under standard light source irradiation; therefore, the photovoltaic composite material of the application not only has stable photoelectric conversion efficiency, but also has good durability. (3) The photovoltaic composite material also has good flexibility, and can be applied to various scenes such as photovoltaic clothes, building integrated photovoltaic products (such as flexible building products), wearable devices, tents, curtains, etc., and can provide a portable power supply solution for areas far from power supply. DETAILED DESCRIPTION

[0032] In order to make the above-mentioned objects, features and advantages of the application more apparent and easy to understand, the application will be further described in detail below with specific embodiments.

[0033] Embodiment 1

[0034] The preparation method of the photovoltaic composite material of the embodiment includes the following preparation steps:

[0035] a) Preparation of the flexible conductive textile substrate: silver-plated polyamide fibers (with a diameter of 0.1 mm and a resistivity of 3.8^-2Ω·m) were used as conductive yarns, and were woven according to a twill weave, with a warp density of 50 threads / cm and a weft density of 40 threads / cm, to form a conductive network, thereby obtaining the flexible conductive textile substrate (with a thickness of 0.2 mm).

[0036] b) Preparation of the integrated film material: the integrated film material comprises a lower encapsulation film, a photovoltaic adhesive film and an upper encapsulation film which are sequentially stacked and co-extruded; the materials used for the lower encapsulation film and the upper encapsulation film are both thermoplastic polyurethane (TPU); the material used for the photovoltaic adhesive film is obtained by adding and dispersing 7% (by mass percentage, the same below) of PM6:Y6 and 5% of perovskite quantum dots CsPbBr3 into TPU as the base material to serve as the light-active substance of the photovoltaic adhesive film; the materials used for the three layers of the lower encapsulation film, the photovoltaic adhesive film and the upper encapsulation film are melted at 180°C through a three-layer co-extrusion device, and after three-layer co-extrusion, the integrated film material with a thickness of 300 μm is obtained by casting, wherein the thickness of the lower encapsulation film and the upper encapsulation film is 50 μm, and the thickness of the photovoltaic adhesive film is 200 μm.

[0037] c) Hot-pressing integrated molding: after the integrated film material is cut to the desired size, the cut integrated film material is placed on the upper surface of the flexible conductive textile substrate, and the upper surface of the integrated film material is covered with a fluorocarbon resin transparent protective layer (with a thickness of 0.1 mm); the flexible conductive textile substrate, the integrated film material and the fluorocarbon resin transparent protective layer are placed in a hot press, and are subjected to hot-pressing integrated molding treatment at 120°C and a pressure of 2 MPa for 5 minutes, so that the lower encapsulation film melts and penetrates into the flexible conductive textile substrate under the action of the hot pressing force, to form ohmic contact between the photovoltaic adhesive film and the conductive network of the flexible conductive textile substrate, and the lower encapsulation film and the upper encapsulation film melt to encapsulate the overall structure by hot-pressing, and after cooling, a photovoltaic composite material of the present embodiment is obtained.

[0038] The photovoltaic composite material of the present embodiment comprises a flexible conductive textile substrate, an integrated film material and a transparent protective layer which are sequentially stacked and hot-pressing integrated molded; the flexible conductive textile substrate is a conductive network formed by interweaving warp yarns and weft yarns, and the warp yarns and / or the weft yarns are conductive yarns; the integrated film material comprises a lower encapsulation film, a photovoltaic adhesive film and an upper encapsulation film which are sequentially stacked and co-extruded; the lower encapsulation film contacts and encapsulates the flexible conductive textile substrate, and the upper encapsulation film contacts and encapsulates the transparent protective layer; the photovoltaic adhesive film penetrates into the flexible conductive textile substrate during hot-pressing integrated molding, to form ohmic contact with the conductive network in the flexible conductive textile substrate.

[0039] The application of the photovoltaic composite material of the embodiment can be applied to various scenes such as building integrated photovoltaic products, photovoltaic clothing, wearable devices, tents, curtains and the like, and can provide a portable power supply solution for areas far from power supply.

[0040] Embodiment 2

[0041] The photovoltaic composite material, the preparation method and the application thereof of the embodiment refer to embodiment 1, and the difference between the embodiment and embodiment 1 is that:

[0042] In the embodiment, the conductive yarn of step a) is woven according to plain weave, and the rest refers to embodiment 1.

[0043] Embodiment 3

[0044] The photovoltaic composite material, the preparation method and the application thereof of the embodiment refer to embodiment 1, and the difference between the embodiment and embodiment 1 is that:

[0045] In the embodiment, the materials of the lower encapsulation film and the upper encapsulation film of step b) are both polyethylene-octene copolymer (POE), and the photovoltaic adhesive film is made of POE as a base material, and the rest refers to embodiment 1.

[0046] Embodiment 4

[0047] The photovoltaic composite material, the preparation method and the application thereof of the embodiment refer to embodiment 1, and the difference between the embodiment and embodiment 1 is that:

[0048] In the embodiment, 14% of PM6:Y6 and 10% of perovskite quantum dots CsPbBr3 are added and dispersed in the photovoltaic adhesive film of step b) as light active substances, and the rest refers to embodiment 1.

[0049] Comparative Example 1

[0050] The photovoltaic composite material, the preparation method and the application thereof of the comparative example refer to embodiment 1, and the difference between the comparative example and embodiment 1 is that:

[0051] In the comparative example, no light active substance is added in the photovoltaic adhesive film of step b), and the rest refers to embodiment 1.

[0052] Comparative Example 2

[0053] The photovoltaic composite material, the preparation method and the application thereof of the comparative example refer to embodiment 1, and the difference between the comparative example and embodiment 1 is that:

[0054] In the comparative example, the hot-pressing integration forming treatment is performed in a hot press at 120℃ and 2MPa pressure for 30 seconds, and the rest refers to embodiment 1.

[0055] Performance test

[0056] The photovoltaic composite materials prepared in Examples 1-4 and Comparative Examples 1-2 were tested for performance, and the test results are shown in Table 1 below:

[0057] Table 1

[0058]

[0059] Based on the data in Table 1, it can be seen that:

[0060] By comparing the preparation methods of the photovoltaic composite materials of Example 1, Example 2 and Example 3, it can be seen that: the weaving method of the flexible conductive textile substrate and the proper adjustment of the materials of the lower encapsulation film and the upper encapsulation film and the matrix material of the photovoltaic adhesive film basically do not have a significant impact on the visible light transmittance, volume resistance, photoelectric conversion efficiency and other performances, and the photoelectric conversion efficiency retention rate after bending and the anti-power decay of Examples 1-3 are all good, so the photovoltaic composite materials of Examples 1-3 have good durability.

[0061] By comparing the photovoltaic composite materials of Example 1, Example 4 and Comparative Example 1, it can be seen that: as the addition amount of the photoactive substance in the photovoltaic adhesive film increases, the photoelectric conversion efficiency is significantly improved. However, it should be noted that if the addition amount of the photoactive substance in the photovoltaic adhesive film is too much (such as more than 30%), it will greatly affect the visible light transmittance of the photovoltaic composite material, making the visible light transmittance significantly decrease, and thus the light absorption and utilization rate of the photovoltaic composite material will decrease, and therefore the photoelectric conversion efficiency will decrease.

[0062] By comparing the preparation methods of the photovoltaic composite materials of Example 1 and Comparative Example 2, it can be seen that: when the time of hot-pressing integrated forming treatment is too short (such as Comparative Example 2), the interlayer peeling strength of the flexible conductive textile substrate and the photovoltaic adhesive film is significantly decreased, and the adhesion is insufficient; and under the condition of a bending radius of 5 mm, the photoelectric conversion efficiency retention rate of Comparative Example 2 is also decreased after 10,000 bending cycles; and the power decay after irradiation for 1,000 hours under standard light source irradiation is also increased. It shows that the adhesion degree of the flexible conductive textile substrate and the photovoltaic adhesive film has a great influence on the overall performance of the photovoltaic composite material, and the hot-pressing integrated forming process needs to be strictly controlled in actual operation.

[0063] In addition, it should be noted that if the time of hot-pressing integrated forming treatment is too long, it will increase the process time of preparing the photovoltaic composite material, reduce the production efficiency, and at the same time, increase the flowability of the molten lower encapsulation film and upper encapsulation film during lamination, which is easy to cause phenomena such as glue overflow, fiber displacement in the flexible conductive textile substrate and material aggregation in the photovoltaic adhesive film, and thus will have adverse effects on the overall material structure and performance of the photovoltaic composite material.

[0064] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0065] The technical solution provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A photovoltaic composite material, characterized in that, It includes a flexible conductive textile substrate, an integrated film material, and a transparent protective layer that are sequentially stacked and hot-pressed into a single unit; The flexible conductive textile substrate is a conductive network formed by interlacing and weft yarns, and the warp yarns and / or weft yarns are conductive yarns; The integrated film material includes a lower encapsulation film, a photovoltaic encapsulation film, and an upper encapsulation film that are sequentially stacked and co-extruded; the photovoltaic encapsulation film uses a matrix material and photoactive substances dispersed in the matrix material; the lower encapsulation film and the upper encapsulation film use thermoplastic encapsulation materials that are the same as and / or compatible with the matrix material of the photovoltaic encapsulation film. The lower encapsulation film contacts and encapsulates the flexible conductive textile substrate, while the upper encapsulation film contacts and encapsulates the transparent protective layer. The photovoltaic film is infiltrated into the flexible conductive textile substrate during the thermo-pressing integrated molding process to form an ohmic contact with the conductive network.

2. The photovoltaic composite material according to claim 1, characterized in that, The conductive yarn is at least one of silver-plated nylon fiber, stainless steel metal fiber, and conductive polymer-coated fiber; the resistivity of the conductive yarn is less than 10^-2 Ω·m, and its diameter is between 0.05 and 0.5 mm. The conductive yarn is woven in one of the following weave patterns: plain weave, twill weave, or satin weave to form a conductive network with multiple parallel and / or series conductive circuits; the thickness of the flexible conductive textile substrate is 0.05mm-5mm.

3. The photovoltaic composite material according to claim 1, characterized in that, The matrix material is at least one of ethylene-vinyl acetate copolymer, polyethylene-octene copolymer, and thermoplastic polyurethane; The photoactive material is an organic photovoltaic material and / or perovskite quantum dots.

4. A photovoltaic composite material according to claim 3, characterized in that, The photoactive material is added at a mass percentage of 5-30%; the thickness of the photovoltaic film is 50-500 μm.

5. A photovoltaic composite material according to claim 4, characterized in that, The photoactive material uses organic photovoltaic materials as the main active material and introduces perovskite quantum dots as performance enhancers. The organic photovoltaic material is added at a mass percentage of 7-14%, and the organic photovoltaic material is selected from at least one of PM6:Y6 and PM6:L8-BO. The perovskite quantum dots added are 5-10% by mass, and the perovskite quantum dots are selected from at least one of CsPbI3 quantum dots, CsPbI2Br quantum dots, and CsPbBr3 quantum dots.

6. A photovoltaic composite material according to claim 1, characterized in that, The materials used for the lower and upper encapsulation films are at least one of ethylene-vinyl acetate copolymer, polyethylene-octene copolymer, and thermoplastic polyurethane; the thickness of both the lower and upper encapsulation films is 50-200 μm.

7. A photovoltaic composite material according to claim 1, characterized in that, The transparent protective layer is a transparent film material made of fluorocarbon resin and / or polyethylene terephthalate; the thickness of the transparent protective layer is 0.01-0.5 mm; The average transmittance of the photovoltaic composite material after hot-pressing integrated molding is not less than 75% in the visible light range.

8. A method for preparing a photovoltaic composite material according to any one of claims 1-7, characterized in that, The preparation steps include the following: S1. Preparation of flexible conductive textile substrate: The flexible conductive textile substrate is obtained by using conductive yarn as warp and / or weft yarn, and forming a conductive network through the interlacing of warp and weft yarns. S2. Preparation of integrated film material: Photoactive substances are uniformly dispersed in the matrix material to obtain the material used for photovoltaic encapsulant film; The materials used for the three-layer structure of lower encapsulation film, photovoltaic encapsulant film and upper encapsulation film are melted separately and then processed by three-layer co-extrusion casting process to obtain integrated film material; S3. Hot-press integrated molding: The flexible conductive textile substrate, integrated film material and transparent protective layer are stacked in sequence and then hot-pressed to form an integrated structure. Under the action of hot pressure, the lower encapsulation film melts and penetrates into the flexible conductive textile substrate, so that the photovoltaic film and the conductive network of the flexible conductive textile substrate form an ohmic contact. The lower encapsulation film and the upper encapsulation film are encapsulated by hot-pressing and melting to obtain the photovoltaic composite material.

9. A photovoltaic composite material according to claim 1, characterized in that, In step S3, the hot pressing temperature for the integrated hot pressing molding is controlled at 80-150℃, the pressure is 0.5-5MPa, and the time is 1-10 minutes.

10. The application of a photovoltaic composite material according to any one of claims 1-7, characterized in that, The photovoltaic composite material can be applied to building-integrated photovoltaic products, photovoltaic clothing, wearable devices, tents or curtains to provide portable power.

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