Reflective film and solar cell panel

Abstract

The invention discloses a reflective film and a solar cell panel, and relates to the technical field of solar photovoltaic power generation. The reflective film comprises an adhesive film layer and a reflective layer, the microstructure layer is arranged on the adhesive film layer; the reflective layer is arranged on the microstructure layer; wherein the reflective layer, the microstructure layer and the adhesive film layer are sequentially arranged from top to bottom, so that the reflective film with the thin structure is formed. The problems that a traditional reflective film adopts a multi-layer structure, so that the thickness of a reflective film product is high, space assembly with smaller gaps is not facilitated, and a multi-layer attaching structure also causes light energy attenuation are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar photovoltaic power generation, and particularly to a reflective film and a solar panel. Background Art

[0002] Solar photovoltaic power generation is one of the important forms of using solar energy, which can reduce the dependence on and consumption of non-renewable fossil fuels and reduce environmental pollution. At present, solar power generation battery modules based on the photovoltaic effect principle have been relatively mature. Conventional solar modules mainly consist of an encapsulation adhesive layer, a cell array, a backsheet, and glass, etc. A single cell is not sufficient to be used as a power source, and current conduction must be achieved through series connection of solder tapes to reach the power output of the module. However, the presence of solder tapes causes some sunlight to be unable to be absorbed and utilized by the cells, resulting in waste of light energy. In order to improve the photoelectric conversion efficiency of solar modules, the prior art uses a reflective film attached to the solder tapes to utilize the originally wasted sunlight.

[0003] Traditional reflective films usually consist of an aluminum layer, a prismatic micro-structure layer, a PET film layer, and an EVA adhesive film layer, etc. Among them, the prismatic structure provides an appropriate reflection angle, the aluminum layer provides the reflection function, the substrate provides the mechanical strength such as the load-bearing capacity and stiffness of the reflective film, and the EVA adhesive film provides adhesiveness for easy attachment and use. Such a multi-layer structure results in a relatively high thickness of the reflective film product, which is not conducive to assembly in a smaller gap space, and the multi-layer attachment structure also causes attenuation of light energy. For the above problems, no effective solution has been proposed yet. Summary of the Invention

[0004] Object of the Invention: To provide a reflective film and a solar panel to at least solve one of the problems existing in the above prior art.

[0005] Technical Solution: A reflective film includes: An adhesive film layer; A micro-structure layer disposed on the adhesive film layer; and A reflective layer disposed on the micro-structure layer; Wherein, the reflective layer, the micro-structure layer, and the adhesive film layer are sequentially and orderly arranged from top to bottom to form a thin-structured reflective film.

[0006] Preferably, the adhesive film layer is a TPU adhesive film layer or an SCA hot-melt adhesive film layer.

[0007] Preferably, the thickness of the adhesive film layer is 10 - 80 um.

[0008] Preferably, the micro-structure layer is an orderly array of a number of triangular cross-section structures, and the micro-structure layer is formed by curing UV-type acrylic glue.

[0009] Preferably, the apex angle of the triangle is 30 - 160°, and its height is 5 - 30 um.

[0010] Preferably, the microstructure layer is formed by one or more of nanoimprinting, laser processing, microstructured roll transfer printing, die forming, 3D printing, or hot pressing.

[0011] Preferably, the reflective layer is a metal coating, and the metal coating is one of aluminum or silver.

[0012] Preferably, the thickness of the reflective layer is 10 nm - 500 nm.

[0013] Preferably, the reflective layer is coated with a micro-nano scale thickness by one or more of magnetron sputtering, vacuum evaporation, chemical vapor deposition, or electroplating.

[0014] To achieve the above object, according to another aspect of the present application, a solar panel is also provided.

[0015] The solar panel according to the present application includes the reflective film described above; It further includes: a backsheet and a photovoltaic glass. The adhesive film layer of the reflective film is directly adhered to the backsheet, and the photovoltaic glass covers the reflective film.

[0016] Beneficial effects: In the embodiments of the present application, by optimizing the interlayer structure, the reflective layer, the microstructure layer, and the adhesive film layer are sequentially arranged from top to bottom in an orderly manner to form a thin-structured reflective film, achieving the purpose of significantly reducing the overall thickness of the gap reflective film product, thereby realizing the technical effects of reducing the product thickness and improving the optical performance. Furthermore, it solves the technical problems that traditional reflective films are usually composed of an aluminum layer, a prism-type microstructure layer, a PET film layer, an EVA adhesive film layer, etc. Among them, the prism structure provides an appropriate reflection angle, the aluminum layer provides the reflection function, the substrate provides the mechanical strength such as the load-bearing capacity and stiffness of the reflective film, and the EVA adhesive film provides adhesiveness for convenient attachment and use. Such a multi-layer structure results in a relatively high thickness of the reflective film product, which is not conducive to the space assembly of smaller gaps, and the multi-layer attachment structure also causes light energy attenuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic plan view of the reflective film of the present invention.

[0018] Reference numerals are: 10. Adhesive film layer; 20. Microstructure layer; 30. Reflective layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To enable those skilled in the art to better understand the solution of this application, the following will clearly and completely describe the technical solution in the embodiments of this application in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of this application.

[0020] It should be noted that the terms "first", "second", etc. in the specification, claims and above-mentioned drawings of this application are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances for the embodiments of this application described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0021] In addition, the terms "installed", "set up", "provided with", "connected", "connected together", "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can also be internal communication between two devices, components or parts. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will detail this application with reference to the drawings and in conjunction with the embodiments.

[0023] As Figure 1 shown, this application relates to a reflective film and a solar panel. The reflective film includes: a glue film layer 10; which can achieve the effect of direct adhesion, thereby achieving the effect of reducing the product thickness. At the same time, it can also enhance the structural stability and protection.

[0024] A microstructure layer 20, disposed on the glue film layer 10; which can control the light propagation path and achieve directional reflection. By adjusting the reflection angle, the light can be accurately and directionally reflected onto the photovoltaic module, improving the energy capture under morning / evening or diffused light conditions.

[0025] A reflective layer 30, disposed on the microstructure layer 20; which directly reflects the incident light and is the core optical medium; the reflective layer 30 achieves a high reflectivity through specular reflection.

[0026] Among them, the reflective layer 30, the microstructural layer 20, and the adhesive film layer 10 are sequentially arranged in order from top to bottom to form a thin-structured reflective film. It can achieve a good product forming effect, can also greatly reduce the thickness of the product, and at the same time, it is also easy to achieve and convenient to operate.

[0027] Specifically, this application can solve the problem that existing reflective film products all have a PET substrate layer, and the thickness of the PET substrate layer is 20 - 38 um. A prism microstructure is made on the front side, and then an EVA back coating adhesive layer with a thickness of 70 - 80 um is paired. The total thickness is 100 - 150 um. The new type of thin-gap reflective film product proposed by the present invention uses a hot-melt type or thermo-pressing type adhesive film with good film-forming properties and mechanical strength as the substrate. The thickness of its adhesive layer is 10 - 80 um, which can replace the combination of the PET substrate and the EVA adhesive layer in the original reflective film design, and has a thinner base layer than traditional gap film products. Therefore, the overall thickness of the gap reflective film product can be greatly reduced to 20 - 90 um.

[0028] When the overall thickness is reduced, the space can be further given to the reflective microstructure layer 20 to make the microstructure larger, increasing the effective area of the reflective layer 30 to further increase the reflection efficiency.

[0029] This application prepares a substrate-free solar reflective film product. A triangular microstructure is directly transferred on the surface of a hot-melt adhesive film or a thermoplastic optical adhesive film, and then a thin aluminum or silver metal layer is plated to prepare an ultra-thin new type of solar reflective film product.

[0030] Of course, the structure of this application can also be arranged on both sides according to the usage requirements.

[0031] From the above description, it can be seen that this application has achieved the following technical effects: In the embodiment of this application, by optimizing the interlayer structure, through the sequential arrangement of the reflective layer 30, the microstructural layer 20, and the adhesive film layer 10 from top to bottom to form a thin-structured reflective film, the purpose of greatly reducing the overall thickness of the gap reflective film product is achieved, thus realizing the technical effects of reducing the product thickness and improving the optical performance. Furthermore, it solves the technical problem that traditional reflective films are usually composed of an aluminum layer, a prism-type microstructural layer 20, a PET film layer, an EVA adhesive film layer 10, etc. Among them, the prism structure provides an appropriate reflection angle, the aluminum layer provides the reflection function, the substrate provides the mechanical strength such as the load-bearing property and stiffness of the reflective film, and the EVA adhesive film provides adhesiveness for easy attachment and use. Such a multi-layer structure results in a relatively high thickness of the reflective film product, which is not conducive to the space assembly of smaller gaps, and the multi-layer attachment structure also causes light energy attenuation.

[0032] Further, the adhesive film layer 10 is a TPU adhesive film layer 10 or an SCA hot-melt adhesive film layer 10. It can be understood that the TPU adhesive film refers to thermoplastic polyurethane, which has a high elastic modulus (Shore hardness 70A - 95A) and is resistant to low temperatures. It has a high-elasticity buffer microstructure layer 20 to stress, prevent the reflective layer 30 from cracking (especially in the case of curved surface fitting). At the same time, the light transmittance is greater than 90%, avoiding light scattering loss in the adhesive layer.

[0033] The SCA hot-melt adhesive film layer 10 has a fast heat activation characteristic, and the hot-melt bonding speed ≤ 3 seconds (TPU requires 5 - 10 seconds), which improves the production line efficiency. Therefore, the above two adhesive film layers 10 have good adhesiveness, thus ensuring a good bonding effect.

[0034] Further, the thickness of the adhesive film layer 10 is 10 - 80um. It can be understood that by adopting, including but not limited to: precision coating or casting process to control the thickness tolerance of ±2μm, good optical performance can be ensured, and at the same time, good processing efficiency can be achieved.

[0035] Specifically, when the thickness of the adhesive film layer 10 is 10 - 30μm, the ultra-thin design reduces the optical path loss (the light penetration loss through the adhesive layer < 3%), and the brightness is increased by 15%; When the thickness of the adhesive film layer 10 is 30 - 60μm, the bonding strength and flexibility are balanced (the peel strength ≥ 8N / cm); When the thickness of the adhesive film layer 10 is 60 - 80μm, the thickened buffer layer protects the microstructure from impact.

[0036] It should be noted that the above range all has good adhesiveness, thus ensuring the stability of the structure.

[0037] Further, the microstructure layer 20 is an orderly array of several triangular cross-section structures, and the microstructure layer 20 is formed by curing UV-type acrylic glue. It can be understood that the microstructure layer 20 is an array structure formed by tiny structures with a triangular cross-section and arranged according to a certain rule. The arrangement is usually a periodic repeated arrangement, which helps to achieve specific optical or mechanical properties (such as enhanced reflection, anti-adhesion, or light and heat conduction, etc.).

[0038] By curing with UV-type acrylic glue, the microstructure is made of an acrylic glue cured by ultraviolet (UV) light. The UV-type acrylic glue is a photosensitive resin that rapidly undergoes a polymerization reaction and cures into shape under ultraviolet light irradiation. It has the advantages of high processing efficiency, good forming accuracy, and high transparency.

[0039] Therefore, the microstructure layer 20 has a stable structural morphology and good mechanical strength, and at the same time, rapid manufacturing can be achieved, which is suitable for batch processes.

[0040] Furthermore, the microstructure layer 20 can be a regular prism structure or an irregular prism structure, which can meet the requirements of various usage scenarios and thus achieve the effect of flexible use.

[0041] Furthermore, the apex angle of the triangle is 30 - 160°, and its height is 5 - 30 μm. It can be understood that the apex angle (i.e., the included angle) of each triangular pyramid or wedge in the microstructure is limited between 30 - 160 degrees. The angles within this range can achieve a balance between optical properties (such as reflection, refraction, and scattering) and the difficulty of manufacturing processes. At the same time, its height is 5 - 30 micrometers, which can effectively cause optical interference with visible light or near-infrared light or enhance the reflection effect. Preferably, the apex angle of the triangle is 120°.

[0042] Therefore, the design parameters of the triangular structure are optimized, which is beneficial to enhancing the reflection effect, improving the light utilization efficiency, and also taking into account the feasibility of manufacturing.

[0043] Furthermore, the microstructure layer 20 is fabricated by one or more of nanoimprinting, laser processing, microstructured roll-to-roll printing, mold forming, 3D printing, or hot pressing. It can be understood that nanoimprinting uses a mold to transfer patterns onto the material surface at the micro-nano scale and is suitable for large-scale manufacturing.

[0044] Laser processing uses a laser beam to achieve high-precision microstructure etching or ablation.

[0045] Microstructured roll-to-roll printing fabricates the structural pattern on the surface of a roller and transfers it to the adhesive layer by rolling.

[0046] Mold forming is a traditional thermoplastic material processing method and is suitable for high replication accuracy.

[0047] 3D printing is suitable for prototype development or small-batch manufacturing of complex structures.

[0048] Hot pressing means forming the structure under heating and pressure.

[0049] Therefore, the microstructure layer 20 can be prepared by a variety of mature micro-nano processing technologies, with technical diversity and mass production feasibility.

[0050] Furthermore, the reflective layer 30 is a metal coating, and the metal coating is one of aluminum or silver. It can be understood that the reflective layer 30 is the key functional layer of the entire film, and a metal coating is used to enhance the light reflection effect. Preferably, the metal coating is an aluminum layer.

[0051] Aluminum: It has good reflectivity, low cost, and mature processes.

[0052] Silver: It has extremely high reflectivity, especially excellent performance in the visible and infrared regions.

[0053] Therefore, selecting aluminum or silver as the material of the reflective layer 30 can effectively improve the light reflection efficiency of the film layer, thereby enhancing the photoelectric conversion efficiency of the solar panel.

[0054] Furthermore, the thickness of the reflective layer 30 is 10nm - 500nm. It can be understood that this thickness range belongs to the nano-scale coating, which can form an effective light reflection interface without affecting the flexibility or transparency of the overall film layer (depending on the specific design). Preferably, the thickness of the reflective layer 30 is 90nm.

[0055] A lower limit of 10nm can ensure the formation of a continuous film, while 500nm is the upper limit for most metal reflective layers. Exceeding this limit may cause stress cracking or peeling.

[0056] Therefore, this thickness range not only ensures good light reflection performance but also takes into account material stability and process operability.

[0057] Furthermore, the reflective layer 30 is coated with a micro-nano scale thickness by one or more of magnetron sputtering, vacuum evaporation, chemical vapor deposition, or electroplating. It can be understood that magnetron sputtering refers to guiding plasma to sputter metal atoms through a magnetic field, with uniform deposition and being suitable for large-area film formation.

[0058] Vacuum evaporation is to heat the metal to evaporation and deposit it on the substrate in a vacuum, resulting in a high-quality film layer.

[0059] Chemical vapor deposition (CVD) refers to generating a solid thin film through a gas-phase reaction and is suitable for complex morphologies.

[0060] Electroplating refers to depositing metal on the surface through an electrochemical method and is commonly used in scenarios such as thick films or conductive enhancement.

[0061] Therefore, multiple preparation methods can be selected and used according to production requirements and performance goals, providing flexible process options.

[0062] Specifically, it is further illustrated by the following examples: Example 1 The UV-type acrylic glue is coated and cured on a 25um TPU adhesive substrate layer by micro-structure transfer printing to form an isosceles triangle micro-structure array with a vertex angle of 120 degrees and a height of 10um. Then, a metal aluminum layer with a thickness of 90nm is fabricated on the triangular micro-structure by magnetron sputtering to obtain a new type of metal-gap reflective film product without a PET substrate.

[0063] Example 2 The UV-type acrylic glue is coated and cured on the surface of a 30-μm SCA hot melt adhesive film by means of micro-structure transfer printing to form an isosceles triangle micro-structure array with a vertex angle of 120 degrees and a height of 8 μm. Then, a 90-nm-thick aluminum metal layer is fabricated on the triangular micro-structures by means of magnetron sputtering to obtain a new type of metal-gap reflective film product without a PET substrate and with an ultra-thin structure.

[0064] In summary, for the new metal-gap reflective film without a PET substrate, a single-layer TPU adhesive film or SCA hot melt adhesive film with adhesive properties is used to replace the original PET plus EVA adhesive layer structure. Micro-structures are directly fabricated on the surface of the TPU or SCA adhesive film and a metal layer is deposited thereon, so as to greatly reduce the total thickness of the product and achieve a thin design.

[0065] This application also relates to a solar panel, including the above-mentioned reflective film; It further includes: a backplane and a photovoltaic glass. The adhesive film layer 10 of the reflective film is directly pasted on the backplane, and the photovoltaic glass covers the reflective film.

[0066] Specifically, by pasting on the backplane through the adhesive film layer 10, the reflection of light is enhanced and introduced into the battery cells, improving the reuse rate of light. At the same time, the photovoltaic glass serves as the protection and light-incident interface on the surface of the battery and covers the reflective film. Therefore, the above structure can optimize the light-capturing ability of the solar panel and effectively improve the photoelectric conversion efficiency.

[0067] This application has the following beneficial effects: 1. The new structure has no traditional substrate layer, and a single adhesive layer is used to replace the combination of the substrate and the adhesive layer, greatly reducing the overall thickness of the gap reflective film product. 2. On the premise of the same total thickness, the size of the reflective prism structure can be increased, thereby increasing the effective area of the reflective layer and improving the light reflection efficiency.

[0068] In summary, for the metal-gap reflective film product of the present invention, a single adhesive film layer 10 is used to replace the structure of the PET substrate layer plus the back-coated EVA adhesive layer. The reflective micro-structures are directly prepared on the adhesive layer, reducing the total thickness of the gap reflective film and expanding the new application scenarios of the gap reflective film product in a narrower space. At the same time, on the premise of the same total thickness, the size of the reflective micro-structures of the metal-type reflective film product of this application can be increased to further increase the effective area of the reflective layer and improve the light energy utilization rate of the gap reflective film product.

[0069] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations can be made to the technical solutions of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A reflective film, characterized in that, Comprising: A film layer (10); A microstructure layer (20), disposed on the film layer (10); And A reflective layer (30), disposed on the microstructure layer (20); Wherein, the reflective layer (30), the microstructure layer (20) and the film layer (10) are sequentially arranged from top to bottom in order to form a thin - structured reflective film.

2. The reflective film according to claim 1, characterized in that, The film layer (10) is a TPU film layer (10) or an SCA hot - melt film layer (10).

3. The reflective film according to claim 1, wherein The thickness of the film layer (10) is 10 - 80 um.

4. The reflective film according to claim 1, characterized in that, The microstructure layer (20) is formed by sequentially and orderly arraying a number of triangular - cross - section structures, and the microstructure layer (20) is cured and formed by a UV - type acrylic glue.

5. The reflective film according to claim 4, characterized in that, The apex angle of the triangle is 30 - 160°, and its height is 5 - 30 um.

6. The reflective film according to claim 1, wherein The microstructure layer (20) is formed by using one or more of nano - imprinting, laser processing, microstructure roll - transfer printing, mold forming, 3D printing or hot - pressing.

7. The reflective film according to claim 1, characterized in that, The reflective layer (30) is a metal coating, and the metal coating is one of aluminum or silver.

8. The reflective film according to claim 1, wherein The thickness of the reflective layer (30) is 10 nm - 500 nm.

9. The reflective film according to claim 1, wherein The reflective layer (30) is coated with a micro - nano - scale thickness by using one or more of magnetron sputtering, vacuum evaporation, chemical vapor deposition or electroplating.

10. A solar panel, characterized in that, Including the reflective film according to any one of claims 1 - 9; Further comprising: a backplane and a photovoltaic glass, the film layer (10) of the reflective film is directly pasted on the backplane, and the photovoltaic glass covers the reflective film.

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