A high temperature and corrosion resistant photovoltaic reflective film and preparation method thereof

Abstract

The present invention discloses a high-temperature resistant and corrosion-resistant photovoltaic reflective film and a preparation method thereof, belonging to the technical field of reflective film. The high-temperature resistant and corrosion-resistant photovoltaic reflective film of the present invention is composed of an adhesive layer, a PET substrate layer, a prism structure layer and a reflective layer. The material of the adhesive layer is any one of silane-modified waterborne polyurethane adhesive, EVA hot melt adhesive or POE hot melt adhesive; the PET substrate layer is a PET film modified with titanium dioxide; the prism structure layer is composed of closely and continuously arranged regular triangular pyramids, the height of the regular triangular pyramid is 0.025 mm, and the side length of the equilateral triangle is 0.06 mm; the reflective layer is Al 0.75 Ti 0.12 Y 0.04 B x N 0.09‑x composite film. The photovoltaic reflective film provided by the present invention has a simple structure and an easy-to-operate preparation method, can effectively solve problems such as easy fading at high temperatures and easy oxidation and corrosion on the surface of existing PET photovoltaic reflective films, improves the wear resistance and aging resistance of the photovoltaic reflective film at the same time, and has a better light reflection effect, improves the light energy utilization rate, and prolongs the service life of the photovoltaic reflective film.

Description

Technical Field

[0001] The invention belongs to the technical field of reflective film preparation, and in particular relates to a high temperature and corrosion resistant photovoltaic reflective film and a preparation method thereof. Background Art

[0002] Photovoltaic reflective film is a reflective material used to improve the power generation efficiency of photovoltaic modules. It is usually applied to the surface of the welding tape (about 2-4% of the surface of the battery cell is blocked by the welding tape and cannot receive light) or the gap between the battery cells, effectively converging the light energy on the surface of the welding tape and the gap between the cells, improving the utilization rate of light energy, especially in low-light environments.

[0003] The existing photovoltaic reflective film is mainly composed of a base layer, a microstructure layer and a reflective layer. Commonly used materials for the base layer include PET base material, PA base material, PVC base material and PC base material. The PET base material has excellent weather resistance and chemical corrosion resistance, can prevent ultraviolet rays and heat energy from damaging the battery cell, and has a high light transmittance and a low refractive index, but it will fade in a high temperature environment, thereby affecting the reflective effect of the reflective film; the PA base material has high weather resistance and high temperature resistance, but the reflective effect is not good, not as good as the PET base material; the PVC base material has low cost, high hardness, light weight, strong sound insulation and heat insulation, but its weather resistance is poor, it is sensitive to ultraviolet rays, oxidation and microorganisms, and cannot be used for a long time in high temperature and humid environments; the PC base material has strong wear resistance, corrosion resistance, UV resistance and strength, and has good optical transparency, but the cost is high and the scope of application is small. Referring to factors such as application scenarios, technical indicators and costs, the technical personnel of the present invention select PET as the base material of the photovoltaic reflective film, and modify it to improve the high temperature resistance, reflectivity and other properties of the PET base material to achieve the best reflection effect and economic effect.

[0004] At present, the commonly used structure of the microstructure layer is the micro-angle prism type. The different materials, shapes, heights, angles, etc. of the prisms have a huge impact on the reflective effect of the reflective film. The reflective efficiency of the existing triangular micro-angle prism structure can generally reach about 70%.

[0005] The reflective layer is generally a metal aluminum coating, which has a simple production process and a low price. However, it is easily oxidized when coated on the surface of the microstructure layer, is not resistant to acid, alkali and salt corrosion, has insufficient light reflectivity, and the aluminum metal layer is easily scratched during use, which affects the use effect and service life of the photovoltaic reflective film.

[0006] Invention patent CN201910914802.6 discloses a corrosion-resistant aluminum alloy target for photovoltaic reflective film, which adds transition metal elements to the aluminum target to improve the corrosion resistance of the aluminum film, and introduces trace elements to further improve the adhesion and corrosion resistance of the aluminum alloy film. However, the introduction of other elements will affect the reflectivity of the aluminum alloy film, thereby affecting the light energy utilization rate of the photovoltaic reflective film, and the scratch resistance of the aluminum alloy film is general. The patent does not consider these two aspects. Patent CN202222334264.3 discloses a high-temperature resistant laser film, which has an insulation film attached to the upper end surface of the base PET material, and a PTFE heat-resistant layer attached to the upper end surface of the insulation film to improve the high-temperature resistance of the laser film. However, although the PTFE film we know has better heat resistance, it has outstanding non-stickiness and is difficult to bond to the surface of the light reflective film, thereby affecting the use efficiency and service life of the product. Summary of the invention

[0007] The main purpose of the present invention is to provide a high temperature resistant and corrosion resistant photovoltaic reflective film, which has a simple structure and an easy-to-operate preparation method. It can effectively solve the problems of the existing PET photovoltaic reflective film that is easy to fade at high temperatures and easy to oxidize and corrode on the surface. At the same time, it improves the wear resistance and aging resistance of the photovoltaic reflective film, has a better light reflection effect, improves the utilization rate of light energy, and prolongs the service life of the photovoltaic reflective film.

[0008] In order to achieve the purpose of the present invention, the present invention provides a high temperature resistant and corrosion resistant photovoltaic reflective film, comprising an adhesive layer, a PET substrate layer, a prism structure layer and a reflective layer, wherein the PET substrate layer is bonded to the front surface of the photovoltaic module cell sheet through the adhesive layer, the prism structure layer is arranged on the surface of the PET substrate layer away from the adhesive layer, and the reflective layer is clad on the upper surface of the prism structure layer away from the PET substrate layer;

[0009] The material of the bonding layer is any one of silane-modified water-based polyurethane adhesive, EVA hot melt adhesive or POE hot melt adhesive, the PET substrate layer is a high-temperature resistant modified PET film, and the reflective layer is a corrosion-resistant and wear-resistant aluminum alloy film.

[0010] The prism structure layer is a triangular micro-angle prism structure, which is composed of closely and continuously arranged regular triangular pyramids. The base of the regular triangular pyramid is an equilateral triangle, the side is an isosceles right triangle, and the three side surfaces are perpendicular to each other; the height of the regular triangular pyramid is 0.025mm, and the side length of the equilateral triangle is 0.06mm.

[0011] The triangular micro-angle prism structure of the present invention realizes directional reflection of light by utilizing the principle of total reflection of light on mutually perpendicular planes, thereby improving the light energy utilization rate of the cell. Through the appropriate height of the regular triangular pyramid and the length of the bottom surface, the receiving angle range of the incident light can be effectively expanded, and the reflected light can be reflected in a directional manner, thereby improving the reflection efficiency of the photovoltaic reflective film.

[0012] Furthermore, the material of the bonding layer is silane-modified waterborne polyurethane adhesive with a thickness of 30-60 μm. The silane-modified waterborne polyurethane adhesive has good wettability and adhesion to the surface of the cell, and reduces the pH value, protecting the cell from corrosion by the alkaline adhesive, thereby improving the reflective effect and service life of the present invention.

[0013] Furthermore, the high temperature resistant modified PET film is a PET film modified by titanium dioxide, and has a thickness of 60-120 μm.

[0014] Furthermore, the preparation method of the high temperature resistant modified PET film specifically comprises the following steps:

[0015] S1. PET film pretreatment: soak the PET film in acetone, ultrasonicate for 10 min, and then rinse with anhydrous ethanol and deionized water in sequence to obtain a pretreated PET film;

[0016] S2. Preparation of TiO2 precursor sol: add isopropyl titanate to anhydrous ethanol and stir evenly, then mix an appropriate amount of deionized water and diethanolamine evenly, then add an appropriate amount of sodium silicate and stir evenly to obtain a TiO2 precursor sol;

[0017] S3. Add 40wt% acetic acid solution to the above-mentioned TiO2 precursor sol, stir at 50±5℃ for 0.5-1h to obtain a mixed sol; apply the mixed sol on the upper surface of the above-mentioned pretreated PET film (i.e., the side of the pretreated PET film away from the bonding layer), the coating times are not less than three times (to ensure that the thickness of the TiO2 film on the surface of the PET film is 10-20μm), so that the surface of the pretreated PET film is evenly coated, and then place it at 150-170℃ for 8-10h, cool to room temperature, wash with ethanol, and dry to obtain a high temperature resistant modified PET film.

[0018] Furthermore, the mass ratio of isopropyl titanate, anhydrous ethanol, deionized water and diethanolamine is 1:(6-8):(0.2-0.3):(0.5-0.7); the mass ratio of isopropyl titanate to the sodium silicate is 1:(0.1-0.2); and the amount of the 40wt% acetic acid solution added is 0.3-0.5 times the mass of the TiO2 precursor sol.

[0019] The present invention adopts a sol-gel method to prepare a transparent nano-TiO2 film on a PET film, which not only improves the reflection efficiency of incident light and reduces the loss of incident light, but also forms a protective layer on the surface of the PET film, has an excellent heat insulation effect, and significantly improves the high temperature resistance, corrosion resistance and weather resistance of the PET film.

[0020] Furthermore, the PET film is selected from PET A4300 of Japan's Toyobo TOYOBO. This type of PET film has excellent heat resistance, water resistance and chemical resistance, and has good light transmittance, which ensures that the reflective film of the present invention has excellent high temperature resistance and corrosion resistance, and also has excellent reflection effect, further improving the reflection efficiency of the present invention and improving the utilization rate of solar energy by the battery. Preferably, the thickness of the PET film is 0.075 mm (75 μm).

[0021] Furthermore, the corrosion-resistant and wear-resistant aluminum alloy film is Al 0.75 Ti 0.12 Y 0.04 B x N 0.09-x Composite film, wherein 0.09>x>0.05, the Al 0.75 Ti 0.12 Y 0.04 B x N 0.09-x The thickness of the composite film is 90-120nm.

[0022] Furthermore, the preparation process of the corrosion-resistant and wear-resistant aluminum alloy film is as follows:

[0023] Weigh Al by atomic percentage 0.75 Ti 0.12 Y 0.04 B x N 0.09-x The Al, Ti, Y, B and BN powders in the composite film are placed in a ball mill for ball milling at a ball milling rate of 480 r / min, a ball-to-material ratio of 9:1, and a ball milling time of 4 h. The ball-milled powder is then mixed with anhydrous ethanol at a mass ratio of 12:1, stirred until viscous, and applied to the upper surface of the prism structure layer (i.e., the side of the prism structure layer away from the PET substrate layer), and dried at 100°C for 2 h. A semiconductor laser is then used for cladding to remove surface impurities to obtain the desired corrosion-resistant and wear-resistant aluminum alloy film.

[0024] The present invention uses laser to 0.75 Ti 0.12 Y 0.04 B x N 0.09-x The composite film is clad on the upper surface of the prism structure layer. The aluminum alloy film is made by introducing Ti, Y, B and N elements. 0.75Ti 0.12 Y 0.04 B x N 0.09-x The composite film has high strength, high hardness, high wear resistance and corrosion resistance, and high reflectivity. Y is doped in the aluminum alloy film, so that the hardness, wear resistance and corrosion resistance of the reflective layer are improved, and the reflective layer is guaranteed to still have a high reflectivity; Ti doping further ensures the high strength of the reflective layer, while improving the corrosion resistance of the reflective layer, so that the light reflectivity of the reflective layer is significantly improved; BN powder is added as a whole, which not only improves the light reflectivity of the reflective layer, but also reduces the temperature of the reflective film of the present invention during the illumination process, and prolongs the service life of the reflective film of the present invention; B doping increases the hardness, wear resistance and corrosion resistance of the reflective layer, reduces the roughness of the reflective layer, and then improves the light reflectivity of the reflective layer. The present invention not only improves the strength, wear resistance and corrosion resistance and thermal conductivity of the aluminum alloy film by doping the aluminum alloy with multiple elements in appropriate proportions and components, but also ensures that the light reflectivity of the aluminum alloy film will not be reduced. On the contrary, the light reflectivity of the aluminum alloy film is greatly improved, and the cost is reduced.

[0025] The present invention also provides a method for preparing a high temperature resistant and corrosion resistant photovoltaic reflective film, which specifically comprises the following steps:

[0026] P1. Evenly drip UV glue on the surface of the PET substrate layer on the transmission device, pre-cured, and then embossed with a mold roller with a triangular micro-angle prism structure, and then cured with ultraviolet light to obtain a prism structure layer with a triangular micro-angle prism structure. Preferably, the material of the prism structure layer is PMMA.

[0027] P2. The prism structure layer obtained in step P1 is placed at 80-90°C for 20-30 minutes to obtain a pre-treated micro-prism layer. The micro-prism layer is pre-treated to ensure that there are no impurities on the surface of the micro-prism layer and to improve the adhesion of the reflective layer on the surface of the micro-prism layer.

[0028] P3. In an argon environment, a reflective layer is clad on the upper surface of the preheated microprism layer. The laser power is 1200 W, the cladding rate is 3 mm / s, the spot diameter is 3 mm, and the overlap rate is 35%.

[0029] P4. Coat the lower surface of the PET substrate layer with an adhesive layer so that it is tightly bonded to the welding strip on the front side of the photovoltaic module cell, and finally obtain the required high temperature and corrosion resistant photovoltaic reflective film on the front side of the photovoltaic module cell.

[0030] The present invention has achieved the following beneficial effects:

[0031] 1. The photovoltaic reflective film of the present invention uses PET film as the substrate layer, performs high temperature sensitization on the PET film, and then bonds the PET film to the solar cell through a silane-modified water-based polyurethane adhesive. A UV curing embossing process is used to form a prism structure layer on a layer of the high temperature modified PET film, and then Al is clad on the prism structure layer. 0.75 Ti 0.12 Y 0.04 B x N 0.09-x The composite film is obtained. The structure of the invention is simple, the preparation process is conventional and easy to operate, and the material of the photovoltaic reflective film is set to ensure that the invention has good high temperature resistance and can withstand solar radiation in a high temperature environment; the light transmittance is high to avoid light pollution caused by excessive reflection; the reflectivity is relatively high, which can reach more than 95%, and the reflection is uniform and stable; the wear resistance, corrosion resistance and aging resistance are excellent, and it is not easy to fade or age in a light environment, thereby extending the service life of the photovoltaic reflective film.

[0032] 2. The present invention strictly controls Al 0.75 Ti 0.12 Y 0.04 B x N 0.09-x The content of each element in the composite film not only significantly improves the strength, wear resistance, corrosion resistance and thermal conductivity of the aluminum alloy film, but also significantly improves the light reflectivity of the reflective layer, further ensuring the high reflectivity of the reflective film of the present invention.

[0033] 3. The present invention is composed of an adhesive layer, a PET substrate layer, a prism structure layer and a reflective layer. The layers have good bonding properties and are not easy to crack. The layers interact with each other, thereby ensuring the high temperature resistance, high wear resistance, corrosion resistance and high reflectivity of the photovoltaic reflective film of the present invention, improving the utilization rate of light energy and extending the service life of the photovoltaic reflective film. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic structural diagram of the high temperature and corrosion resistant photovoltaic reflective film of the present invention.

[0035] Figure symbols: 1. Adhesive layer; 2. PET substrate layer; 3. Prism structure layer; 4. Reflective layer. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] like Figure 1As shown, the present invention provides a method for preparing a high temperature resistant and corrosion resistant photovoltaic reflective film, which specifically comprises the following steps:

[0038] P1. The UV glue is evenly dripped on the surface of the PET substrate layer 2 on the transmission device. After pre-curing, the microstructure is embossed by a mold roller with a triangular micro-corner prism structure (the temperature of the mold roller is 140°C, and the rolling rate is 1.0m / min), and then cured by ultraviolet light to obtain a prism structure layer 3 with a triangular micro-corner prism structure with a thickness of 20-30μm. Among them, the triangular micro-corner prism structure is composed of closely and continuously arranged regular triangular pyramids, the base of which is an equilateral triangle, the side is an isosceles right triangle, and the three side surfaces are perpendicular to each other; the height of the regular triangular pyramid is 0.025mm, and the side length of the equilateral triangle is 0.06mm.

[0039] Preferably, the triangular micro-corner prism is customized by Jiangxi Oute Optics Co., Ltd. according to requirements and is made of PMMA.

[0040] P2. Place the prismatic structure layer 3 obtained in step P1 at 80-90°C for 20-30 minutes to obtain a pretreated micro-prismatic layer.

[0041] P3. Under argon environment, the reflective layer 4 is clad on the upper surface of the micro-prism layer after preheating (i.e., the upper surface of the prism structure layer 3 away from the PET substrate layer 2), the laser power is 1200W, the cladding rate is 3mm / s, the spot diameter is 3mm, and the overlap rate is 35%.

[0042] The above-mentioned reflective layer is a corrosion-resistant and wear-resistant aluminum alloy film, and the corrosion-resistant and wear-resistant aluminum alloy film is Al 0.75 Ti 0.12 Y 0.04 B x N 0.09-x Composite film, where 0.09>x>0.05, Al 0.75 Ti 0.12 Y 0.04 B x N 0.09-x The thickness of the composite film is 90-120nm. 0.75 Ti 0.12 Y 0.04 B x N 0.09-x The preparation process of the composite membrane is:

[0043] Weigh Al by atomic percentage 0.75 Ti 0.12 Y 0.04 B x N 0.09-xThe Al, Ti, Y, B and BN powders in the composite film are placed in a ball mill for ball milling at a ball milling rate of 480 r / min, a ball-to-material ratio of 9:1, and a ball milling time of 4 h. The ball-milled powder is then mixed with anhydrous ethanol at a mass ratio of 12:1, stirred until viscous, applied to the upper surface of the prism structure layer, and dried at 100 ° C for 2 h. A semiconductor laser is then used for cladding to remove surface impurities to obtain the desired corrosion-resistant and wear-resistant aluminum alloy film.

[0044] P4. Coat the lower surface of the PET substrate layer 2 with an adhesive layer 1 so that it is tightly bonded to the welding strip on the front side of the photovoltaic module cell, and finally obtain the required high temperature and corrosion resistant photovoltaic reflective film on the front side of the photovoltaic module cell.

[0045] The material of the bonding layer 1 is any one of silane-modified waterborne polyurethane adhesive, EVA hot melt adhesive or POE hot melt adhesive. Preferably, the bonding layer has a thickness of 30-60 μm and is made of silane-modified waterborne polyurethane adhesive, selected from KONISHI's waterborne silanized polyurethane adhesive SU500.

[0046] The PET substrate layer 2 is a high temperature resistant modified PET film, and its preparation method specifically comprises the following steps:

[0047] S1. PET film pretreatment: soak the PET film in acetone, ultrasonicate for 10 minutes, and then rinse with anhydrous ethanol and deionized water in sequence to obtain a pretreated PET film. The PET film is selected from PET A4300 of Toyobo, Japan, with a thickness of 0.075 mm.

[0048] S2. Preparation of TiO2 precursor sol: Add isopropyl titanate to anhydrous ethanol and stir evenly, then mix appropriate amounts of deionized water and diethanolamine evenly, then add appropriate amount of sodium silicate and stir evenly to obtain TiO2 precursor sol.

[0049] S3. Add 40wt% acetic acid solution to the above-mentioned TiO2 precursor sol, stir at 50±5℃ for 0.5-1h to obtain a mixed sol; apply the mixed sol on the upper surface of the above-mentioned pretreated PET film (i.e., the side of the pretreated PET film away from the bonding layer), the coating number is not less than three times, so that the surface of the pretreated PET film is evenly coated, and then place it at 150-170℃ for 8-10h, cool to room temperature, wash with ethanol, and dry to obtain a high temperature resistant modified PET film.

[0050] Among them, the mass ratio of isopropyl titanate, anhydrous ethanol, deionized water and diethanolamine is 1: (6-8): (0.2-0.3): (0.5-0.7); the mass ratio of isopropyl titanate and sodium silicate is 1: (0.1-0.2); the amount of 40wt% acetic acid solution added is 0.3-0.5 times the mass of TiO2 precursor sol.

[0051] The high temperature resistant modified PET film and the corrosion resistant and wear resistant aluminum alloy film of the present invention are described below in conjunction with specific embodiments.

[0052] Example 1 High temperature resistant modified PET film

[0053] The preparation method of the high temperature resistant modified PET film of this embodiment is as follows:

[0054] S1. PET film pretreatment: The PET film was immersed in acetone, ultrasonicated for 10 min, and then rinsed with anhydrous ethanol and deionized water in sequence to obtain a pretreated PET film.

[0055] S2. Preparation of TiO2 precursor sol: Add 100 parts of isopropyl titanate into 700 parts of anhydrous ethanol and stir evenly, then mix 25 parts of deionized water and 60 parts of diethanolamine evenly, then add 15 parts of sodium silicate, stir at a rate of 1200r / mi for 2h to obtain TiO2 precursor sol.

[0056] S3. Add 360 parts of 40wt% acetic acid solution to the above-mentioned TiO2 precursor sol, stir at 50±5℃ for 11h to obtain a mixed sol; apply the mixed sol on the upper surface of the above-mentioned pretreated PET film (i.e., the side of the pretreated PET film away from the bonding layer), apply it three times to make the surface of the pretreated PET film evenly coated, then keep it at 160℃ for 10h, cool to room temperature, wash with ethanol, and dry to obtain a high-temperature resistant modified PET film with a thickness of 0.1±0.01mm.

[0057] After testing, the reflectivity of Example 1 in the 632.8nm band is 95.3%; the thermal shrinkage under the conditions of 180℃×30min is 0.6%; after being placed at 300℃ for 1h, the surface of the modified PET film (i.e. the side coated with TiO2) has no color spots and no yellowing.

[0058] Comparative Example 1

[0059] The PET film in Comparative Example 1 was not subjected to high temperature modification and was selected from PET A4300 produced by TOYOBO of Japan, with a thickness of 0.1 mm.

[0060] After testing, the reflectivity of Comparative Example 1 in the 632.8nm band was 16.8%; the thermal shrinkage under the condition of 180°C×30min was 3.5%; and the surface of the PET film was severely yellowed after being placed at 300°C for 1h.

[0061] Comparative Example 2

[0062] The modified PET film in Comparative Example 2 is prepared in the same manner as in Example 1, with specific reference to Example 1, except that sodium silicate is not added in Comparative Example 2.

[0063] After testing, the reflectivity of Comparative Example 2 in the 632.8nm band was 92.6%; the thermal shrinkage under the conditions of 180°C×30min was 1.2%; and after being placed at 300°C for 1h, the surface of the PET film turned slightly yellow.

[0064] Corrosion-resistant and wear-resistant aluminum alloy film: Al 0.75 Ti 0.12 Y 0.04 B x N 0.09-x Composite film

[0065] Example 2

[0066] The Al in Example 2 0.75 Ti 0.12 Y 0.04 B x N 0.09-x The preparation process of the composite membrane is:

[0067] Weigh Al by atomic percentage 0.75 Ti 0.12 Y 0.04 B 0.06 N 0.03 The Al, Ti, Y, B and BN powders in the composite film, namely 75at.% Al powder, 12at.% Ti powder, 4at.% Y powder, 6at.% B powder and 3at.% BN powder, were placed in a ball mill for ball milling, with a ball milling rate of 480r / min, a ball-to-material ratio of 9:1, and a ball milling time of 4h; then the ball-milled powder was mixed with anhydrous ethanol at a mass ratio of 12:1, stirred until viscous, applied on the upper surface of the prism structure layer, and dried at 100°C for 2h; then a semiconductor laser was used for cladding, and the cladding process parameters were: laser power of 1200W, cladding rate of 3mm / s, spot diameter of 3mm, and overlap rate of 35%; surface impurities were removed to obtain Al 0.75 Ti 0.12 Y 0.04 B x N 0.09-x Composite membrane.

[0068] Example 3

[0069] The Al in this embodiment 3 0.75 Ti 0.12 Y 0.04 B 0.07 N 0.02 The preparation process of the composite membrane is:

[0070] Weigh Al by atomic percentage 0.75 Ti 0.12 Y 0.04 B 0.07 N 0.02 The Al, Ti, Y, B and BN powders in the composite film, namely 75at.% Al powder, 12at.% Ti powder, 4at.% Y powder, 7at.% B powder and 2at.% BN powder, were placed in a ball mill for ball milling at a ball milling rate of 480r / min, a ball-to-material ratio of 9:1, and a ball milling time of 4h; then the ball-milled powder was mixed with anhydrous ethanol at a mass ratio of 12:1, stirred until viscous, applied to the upper surface of the prism structure layer, and dried at 100°C for 2h; then a semiconductor laser was used for cladding, and the cladding process parameters were: laser power of 1200W, cladding rate of 3mm / s, spot diameter of 3mm, overlap rate of 35%; surface impurities were removed to obtain Al 0.75 Ti 0.12 Y 0.04 B 0.07 N 0.02 Composite membrane.

[0071] Example 4

[0072] The Al of this embodiment 4 0.75 Ti 0.12 Y 0.04 B 0.08 N 0.01 The preparation process of the composite film is the same as that in Example 2, and specific reference is made to Example 2. The difference is that the percentages of the powders weighed in Example 4 are: 75 at.% Al powder, 12 at.% Ti powder, 4 at.% Y powder, 8 at.% B powder and 1 at.% BN.

[0073] Comparative Example 3

[0074] The corrosion-resistant and wear-resistant aluminum alloy film in this comparative example 3 is a 6061 aluminum alloy film.

[0075] Comparative Example 4

[0076] The preparation process of the aluminum alloy composite film in this comparative example 4 is the same as that in Example 2, and specific reference is made to Example 2. The difference is that the percentages of the powders weighed in this example 4 are: 75 at.% Al powder, 12 at.% Ti powder, 4 at.% Y powder, and 9 at.% B powder.

[0077] Comparative Example 5

[0078] The preparation process of the aluminum alloy composite film in this comparative example 5 is the same as that in Example 2, and specific reference is made to Example 2. The difference is that the percentages of the powders weighed in this example 5 are: 75 at.% Al powder, 12 at.% Ti powder, 4 at.% Y powder, and 9 at.% BN powder.

[0079] The aluminum alloy composite films of the above-mentioned embodiments 2-4 and comparative examples 3-5 are clad on the upper surface of the prism structure layer to form a whole, and the thickness of the prism structure layer is 30 μm, and the thickness of the aluminum alloy composite film is 100±5 nm.

[0080] The samples were made by cladding the aluminum alloy composite film on the surface of the prism structure layer obtained by the preparation process of the above-mentioned Examples 2-4 and Comparative Examples 3-5, and their mechanical properties, wear resistance, corrosion resistance and reflectivity were tested. The test results are shown in Table 1 below.

[0081] Table 1 Aluminum alloy composite film performance test results

[0082]

[0083]

[0084] Note: Acid corrosion resistance refers to preparing a 5% hydrochloric acid solution to locally corrode the surface of the sample, observing whether bubbles appear on the surface, and recording the time when the bubbles appear;

[0085] Alkali corrosion resistance refers to preparing a 5% sodium hydroxide solution to locally corrode the surface of the sample, observing whether bubbles appear on the surface, and recording the time when the bubbles appear;

[0086] Reflectivity refers to the reflectivity in the 632.8nm band.

[0087] It can be seen from the experimental results in Table 1 above that the aluminum alloy composite film of the present invention has better mechanical strength, wear resistance, corrosion resistance and reflectivity.

[0088] Application Examples

[0089] The photovoltaic reflective film is prepared by the above-mentioned preparation method with an adhesive layer 1, a PET substrate layer 2, a prism structure layer 3 and a reflective layer 4, wherein the PET substrate layer 2 is a high temperature resistant modified PET film prepared by the method of Example 1; the reflective layer 4 is an Al2O3 film prepared by the method of Example 2. 0.75 Ti 0.12 Y 0.04 B x N 0.09-x Composite film. According to the test, the reflectivity of the photovoltaic reflective film in the 632.8nm band is 99.6%.

[0090] Application comparison

[0091] The photovoltaic reflective film was prepared by using the above-mentioned preparation method with the adhesive layer 1, the PET substrate layer 2, the prism structure layer 3 and the reflective layer 4, wherein the PET substrate layer 2 was the PET film prepared by the method of comparative example 1; and the reflective layer 4 was the 6061 aluminum alloy film prepared by the method of comparative example 3. After testing, the reflectivity of the photovoltaic reflective film in the 632.8nm band was 82.5%.

[0092] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0093] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A high temperature and corrosion resistant photovoltaic reflective film, comprising an adhesive layer, a PET substrate layer, a prism structure layer and a reflective layer, wherein the PET substrate layer is bonded to the front of the photovoltaic module cell sheet through the adhesive layer, the prism structure layer is arranged on the surface of the PET substrate layer away from the adhesive layer, and the reflective layer is clad on the upper surface of the prism structure layer away from the PET substrate layer, characterized in that: The material of the bonding layer is any one of silane-modified water-based polyurethane adhesive, EVA hot melt adhesive or POE hot melt adhesive; The PET substrate layer is a high temperature resistant modified PET film; The prism structure layer is a triangular micro-angle prism structure, which is composed of closely and continuously arranged regular triangular pyramids, the base of which is an equilateral triangle, the side is an isosceles right triangle, and the three side surfaces are perpendicular to each other; the height of the regular triangular pyramid is 0.025 mm, and the side length of the equilateral triangle is 0.06 mm; The reflective layer is a corrosion-resistant and wear-resistant aluminum alloy film; The corrosion-resistant and wear-resistant aluminum alloy film is Al 0.75 Ti 0.12 Y 0.04 B x N 0.09-x Composite membrane, wherein 0.09>x>0.

05.

2. The high temperature and corrosion resistant photovoltaic reflective film according to claim 1, characterized in that: The material of the bonding layer is silane-modified water-based polyurethane adhesive, and the thickness is 30-60 μm.

3. The high temperature and corrosion resistant photovoltaic reflective film according to claim 1, characterized in that: The high temperature resistant modified PET film is a PET film modified by titanium dioxide, and has a thickness of 60-120 μm.

4. The high temperature and corrosion resistant photovoltaic reflective film according to claim 3, characterized in that: The preparation method of the high temperature resistant modified PET film specifically comprises the following steps: S1. PET film pretreatment: soak the PET film in acetone, ultrasonicate for 10 min, and then rinse with anhydrous ethanol and deionized water in sequence to obtain a pretreated PET film; S2. Preparation of TiO2 precursor sol: add isopropyl titanate to anhydrous ethanol and stir evenly, then mix an appropriate amount of deionized water and diethanolamine evenly, then add an appropriate amount of sodium silicate and stir evenly to obtain a TiO2 precursor sol; S3. Add 40wt% acetic acid solution to the above-mentioned TiO2 precursor sol, stir at 50±5℃ for 0.5-1h to obtain a mixed sol; apply the mixed sol on the upper surface of the above-mentioned pretreated PET film (i.e., the side of the pretreated PET film away from the bonding layer), the coating number is not less than three times, so that the surface of the pretreated PET film is evenly coated, and then place it at 150-170℃ for 8-10h, cool to room temperature, wash with ethanol, and dry to obtain a high temperature resistant modified PET film.

5. The high temperature and corrosion resistant photovoltaic reflective film according to claim 4, characterized in that: The mass ratio of isopropyl titanate, anhydrous ethanol, deionized water and diethanolamine is 1: (6-8): (0.2-0.3): (0.5-0.7); the mass ratio of isopropyl titanate to the sodium silicate is 1: (0.1-0.2); the amount of the 40wt% acetic acid solution added is 0.3-0.5 times the mass of the TiO2 precursor sol.

6. The high temperature and corrosion resistant photovoltaic reflective film according to claim 4, characterized in that: The PET film is selected from PET A4300 produced by Japan's Toyobo Co., Ltd.

7. The high temperature and corrosion resistant photovoltaic reflective film according to claim 1, characterized in that: The preparation process of the corrosion-resistant and wear-resistant aluminum alloy film is as follows: Weigh Al by atomic percentage 0.75 Ti 0.12 Y 0.04 B x N 0.09-x The Al, Ti, Y, B and BN powders in the composite film were placed in a ball mill for ball milling at a ball milling rate of 480 r / min, a ball-to-material ratio of 9:1, and a ball milling time of 4 h. The ball-milled powders were then mixed with anhydrous ethanol at a mass ratio of 12:1, stirred until viscous, applied to the upper surface of the prism structure layer, and dried at 100°C for 2 h. Then use a semiconductor laser for cladding to remove surface impurities and obtain the required corrosion-resistant and wear-resistant aluminum alloy film.

8. The high temperature and corrosion resistant photovoltaic reflective film according to claim 1, characterized in that: The Al 0.75 Ti 0.12 Y 0.04 B x N 0.09-x The thickness of the composite film is 90-120nm 9. A method for preparing a high temperature and corrosion resistant photovoltaic reflective film according to any one of claims 1 to 8, characterized in that: The specific steps include: P1. The UV glue is evenly dripped onto the surface of the PET substrate layer on the transmission device. After pre-curing, the microstructure is embossed by a mold roller with a triangular micro-corner prism structure, and then cured by ultraviolet light to obtain a prism structure layer with a triangular micro-corner prism structure. P2. The prismatic structure layer obtained in step P1 is placed at 80-90°C for 20-30min to obtain a pretreated micro-prismatic layer; P3. In an argon environment, a reflective layer was clad on the upper surface of the preheated microprism layer. The laser power was 1200W, the cladding rate was 3mm / s, the spot diameter was 3mm, and the overlap rate was 35%; P4. Coat the lower surface of the PET substrate layer with an adhesive layer so that it is tightly bonded to the welding strip on the front side of the photovoltaic module cell, and finally obtain the required high temperature and corrosion resistant photovoltaic reflective film on the front side of the photovoltaic module cell.

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