阅读说明：本技术 一种高反射率聚酯薄膜、一种高反射型光伏组件背板及一种光伏组件及其应用 (High-reflectivity polyester film, high-reflection type photovoltaic module backboard, photovoltaic module and application of photovoltaic module backboard ) 是由 金亚东 杨承翰 祝炬烨 周玉波 朱正平 于 2020-05-11 设计创作，主要内容包括：本发明涉及一种光伏组件背板用聚酯薄膜,尤其是一种高反射率聚酯薄膜、高反射型光伏组件背板及一种光伏组件及其应用。为了解决现有光伏背板用聚酯薄膜反射率低的问题,本发明提供一种高反射率聚酯薄膜、一种高反射型光伏组件背板及一种光伏组件及其应用。所述的高反射率聚酯薄膜为ABA三层结构,所述的A层包括聚酯、无机粒子a,所述的B层包括聚酯、无机粒子b、聚烯烃和耐水解剂。所述的高反射率聚酯薄膜在波长400nm-1200nm的平均反射率为94.5％-96.5％。所述的高反射率聚酯薄膜应用在光伏组件中,能够提高光伏组件的短路电流密度,提高输出功率。(The invention relates to a polyester film for a photovoltaic module backboard, in particular to a high-reflectivity polyester film, a high-reflectivity photovoltaic module backboard, a photovoltaic module and application thereof. In order to solve the problem of low reflectivity of the existing polyester film for the photovoltaic back plate, the invention provides a high-reflectivity polyester film, a high-reflectivity photovoltaic module back plate, a photovoltaic module and application thereof. The high-reflectivity polyester film is of an ABA three-layer structure, the layer A comprises polyester and inorganic particles a, and the layer B comprises polyester, inorganic particles B, polyolefin and a hydrolysis-resistant agent. The average reflectivity of the high-reflectivity polyester film at the wavelength of 400nm-1200nm is 94.5% -96.5%. The high-reflectivity polyester film is applied to the photovoltaic module, so that the short-circuit current density of the photovoltaic module can be improved, and the output power is improved.)

1. The high-reflectivity polyester film is characterized in that the high-reflectivity polyester film is an ABA three-layer structure, the layer A comprises polyester and inorganic particles a, and the layer B comprises polyester, inorganic particles B, polyolefin and a hydrolysis-resistant agent.

2. The high-reflectivity polyester film of claim 1, wherein the high-reflectivity polyester film has an average reflectivity of 94.5-96.5% in a wavelength band of 400-1200 nm, a breakdown voltage (oil) of 20-29kV, and an elongation at break of 85-130%; the high-reflectivity polyester film is subjected to a high-pressure accelerated humid heat aging test (PCT) for 48 hours, the breaking elongation is 46-88%, and the change of the yellow index is less than 1.

3. The high-reflectivity polyester film according to claim 1, wherein the layer a comprises 97.75-99.55% of polyester selected from polyethylene terephthalate (PET), 0.45-2.25% of inorganic particles a, and the inorganic particles a are titanium dioxide; the B layer comprises 75-89% of polyester, the polyester is selected from polyethylene terephthalate, 5-15% of inorganic particles B, the inorganic particles B are one or the combination of two of titanium dioxide and calcium carbonate, 5-10% of polyolefin, the polyolefin is selected from one or the combination of at least two of polyethylene, polypropylene and poly 4-methylpentene, and 0.1-2% of hydrolysis resistance agent, and the hydrolysis resistance agent is selected from one or the combination of at least two of carbodiimide, dicyclohexylcarbodiimide, N' -diisopropylcarbodiimide and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride.

4. The high-reflectivity polyester film as claimed in claim 3, wherein the layer B comprises 77.4-88.2% of polyester selected from polyethylene terephthalate, 5-13% of inorganic particles B, the inorganic particles B are one or a combination of two of titanium dioxide and calcium carbonate, 5-10% of polyolefin selected from one or a combination of at least two of polyethylene, polypropylene and poly-4-methylpentene, and 0.3-2% of hydrolysis resistance agent selected from one or a combination of at least two of carbodiimide, dicyclohexylcarbodiimide, N' -diisopropylcarbodiimide and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride.

5. The high-reflectivity polyester film according to claim 1, wherein the layer a comprises 97.75-99.55% of polyester selected from polyethylene terephthalate (PET), 0.45-2.25% of inorganic particles a, and the inorganic particles a are titanium dioxide; the layer B comprises 80-84.6% of polyester, the polyester is selected from polyethylene terephthalate, 6-10% of inorganic particles B, the inorganic particles B are titanium dioxide, 7-10% of polyolefin, the polyolefin is the combination of polypropylene and poly-4-methylpentene, 0.3-2% of hydrolysis resistance agent, and the hydrolysis resistance agent is carbodiimide; the polyolefin comprises 3-5% of polypropylene and 3-7% of poly 4-methylpentene; the total thickness of the high-reflectivity polyester film is 150-300 mu m, the thickness of the two A layers accounts for 8-11% of the total thickness, and the thickness of the B layer accounts for 89-92% of the total thickness.

6. The high-reflectance polyester film according to any one of claims 3 to 5, wherein the inorganic particles a have a particle size of 0.1 to 0.3 μm, and the inorganic particles b have a particle size of 0.1 to 0.3 μm.

7. A highly reflective photovoltaic module backsheet, wherein said backsheet comprises the highly reflective polyester film of any one of claims 1 to 6.

8. The highly reflective photovoltaic module backsheet according to claim 7, comprising in order an upper layer, an intermediate layer and a lower layer; the middle layer is selected from the high-reflectivity polyester film of any one of claims 1-6, and the upper and lower layers are respectively selected from one or a combination of at least two of a fluorine film, a fluorine coating layer or a Polyolefin (PO) film.

9. A photovoltaic module comprising glass, solar cells, EVA, frame, junction box, and the highly reflective photovoltaic module backsheet of claim 7 or 8.

10. The photovoltaic module of claim 9 applied to a 1500V power plant.

Technical Field

The invention relates to a polyester film for a photovoltaic module backboard, in particular to a high-reflectivity polyester film, a high-reflectivity photovoltaic module backboard, a photovoltaic module and application thereof.

Background

In recent years, the conversion efficiency of solar cells is increasing, and it is more and more important to improve the conversion efficiency of modules, wherein improving the reflectivity of the back surface of the module is an important measure.

The improvement of the reflectivity of the back of the module can be realized by using white EVA, but the white EVA needs a large amount of white filler to be added, the white filler can migrate to pollute the cell, the cost is increased, the ageing resistance of the EVA is reduced, and the service life of the module is shortened. The improvement of the reflectivity of the back of the assembly can also be realized by improving the reflectivity of the back plate, the titanium dioxide filler is mainly added for improving the reflectivity of the back plate at present, and the back plate becomes brittle and has poor damp-heat aging performance due to excessive addition of the titanium dioxide.

In addition, with the trend of photovoltaic flat-price internet access, power stations gradually shift from 1000V to 1500V in order to improve efficiency and reduce cost, and therefore the back plate is required to have better electrical insulation performance.

Disclosure of Invention

In order to solve the problem of low reflectivity of the existing polyester film for the photovoltaic back plate, the invention provides a high-reflectivity polyester film, a high-reflectivity photovoltaic module back plate, a photovoltaic module and application thereof. The high-reflectivity polyester film provided by the invention has high reflectivity, excellent damp-heat aging performance and excellent electrical insulation performance, can be well applied to photovoltaic modules of 1500V power stations, and enables the photovoltaic modules to have higher output power, better weather resistance and breakdown voltage resistance.

In order to solve the above technical problems, the present invention adopts the following technical solutions.

The invention provides a high-reflectivity polyester film, which is an ABA three-layer structure, wherein an A layer comprises polyester and inorganic particles a; the layer B comprises polyester, inorganic particles B, polyolefin and hydrolysis resistance agent.

Further, high reflectance means reflectance higher than 90%. Further, high reflectance means reflectance higher than 94%.

Further, the high reflectance means that the average reflectance at a wavelength band of 400nm to 1200nm is higher than 90%. Further, high reflectance means that the average reflectance at a wavelength band of 400nm to 1200nm is higher than 94%.

Furthermore, the average reflectivity of the high-reflectivity polyester film in a wave band with the wavelength of 400nm-1200nm is 94.5% -96.5%.

Further, the total thickness of the high-reflectivity polyester film is 150-300 mu m, the thickness of the two A layers accounts for 8-12% of the total thickness, and the thickness of the B layer accounts for 88-92% of the total thickness. The breakdown voltage (oil) is 20-29kV, and the elongation at break is 85-130%.

Further, the high-reflectivity polyester film is subjected to a high-pressure accelerated humid heat aging test (PCT) for 48 hours, the breaking elongation is 46% -88%, and the change of the yellow index is less than 1.

Further, the layer A comprises 97.75-99.55% of polyester, the polyester is selected from polyethylene terephthalate (PET), 0.45-2.25% of inorganic particles a, and the inorganic particles a are titanium dioxide;

the B layer comprises 75-89% of polyester, the polyester is selected from polyethylene terephthalate, 5-15% of inorganic particles B, the inorganic particles B are one or the combination of two of titanium dioxide and calcium carbonate, 5-10% of polyolefin, the polyolefin is selected from one or the combination of at least two of polyethylene, polypropylene and poly 4-methylpentene, and 0.1-2% of hydrolysis resistance agent, and the hydrolysis resistance agent is selected from one or the combination of at least two of carbodiimide, dicyclohexylcarbodiimide, N' -diisopropylcarbodiimide and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride.

Further, the layer B comprises 77.4% -88.2% of polyester, the polyester is selected from polyethylene terephthalate, 5% -13% of inorganic particles B, the inorganic particles B are one or a combination of two of titanium dioxide (namely titanium dioxide) and calcium carbonate, 5% -10% of polyolefin, the polyolefin is selected from one or a combination of at least two of polyethylene, polypropylene and poly-4-methylpentene, and 0.3% -2% of hydrolysis resistance agent, and the hydrolysis resistance agent is selected from one or a combination of at least two of carbodiimide, dicyclohexylcarbodiimide, N' -diisopropylcarbodiimide and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride.

Further, the layer A comprises 97.75-99.55% of polyester, the polyester is selected from polyethylene terephthalate (PET), 0.45-2.25% of inorganic particles a, and the inorganic particles a are titanium dioxide; the layer B comprises 80-84.6% of polyester, the polyester is selected from polyethylene terephthalate, 6-10% of inorganic particles B, the inorganic particles B are titanium dioxide, 7-10% of polyolefin, the polyolefin is the combination of polypropylene and poly-4-methylpentene, 0.3-2% of hydrolysis resistance agent, and the hydrolysis resistance agent is carbodiimide. Further, the polyolefin comprises 3% -5% of polypropylene and 3% -7% of poly 4-methylpentene. Further, the total thickness of the high-reflectivity polyester film is 150-300 mu m, the thickness of the two A layers accounts for 8-11% of the total thickness, and the thickness of the B layer accounts for 89-92% of the total thickness. The foregoing technical solutions include embodiment 3, embodiment 10, and embodiment 13.

Further, the particle diameter of the inorganic particles a is 0.1 to 0.3. mu.m.

Further, the particle diameter of the inorganic particles b is 0.1 to 0.3 μm.

The invention also provides a method for preparing the high-reflectivity polyester film, which comprises the following steps:

(1) adding polyester chips and polyester chips containing inorganic particles a into an extruder A according to the proportion;

(2) adding polyester chips, polyester chips containing inorganic particles B, polyester chips containing polyolefin and polyester chips containing hydrolysis resistance agent into a B extruder according to the proportion;

(3) the melt of the extruder in the layer A and the melt of the extruder in the layer B enter a coat hanger type die head through a filter, a metering pump and a distribution block, and the casting sheets are cast;

(4) and (3) longitudinally stretching, transversely stretching, heat setting, rolling and slitting the casting sheet to obtain the high-reflectivity polyester film.

The high-reflectivity polyester film is applied to the photovoltaic module backboard. The high-reflectivity polyester film is also called as a high-reflectivity polyester film for a photovoltaic module backboard.

The invention also provides a high-reflection photovoltaic module back plate, which comprises the high-reflection polyester film.

Further, the high-reflection photovoltaic module backboard sequentially comprises an upper layer, a middle layer and a lower layer; the middle layer is selected from the high-reflectivity polyester film, and the upper layer and the lower layer are respectively selected from one or a combination of at least two of a fluorine film, a fluorine coating or a Polyolefin (PO) film.

The invention also provides a photovoltaic module which comprises glass, a solar cell, EVA, a frame, a junction box and the high-reflection photovoltaic module backboard.

Further, the photovoltaic module can be applied to 1500V power stations.

Compared with the prior art, the high-reflectivity polyester film (reflective polyester film for short) has higher reflectivity, can increase the short-circuit current density and the output power of the photovoltaic module, has low cost and simple preparation, has excellent aging performance and electrical insulation performance, and is suitable for 1500V power stations. The high-reflection photovoltaic module back plate is high in reflectivity, good in weather resistance and high in breakdown voltage resistance. The photovoltaic module provided by the invention has high output power, better weather resistance and breakdown voltage resistance, and can be applied to 1500V power stations.

Drawings

FIG. 1 is a schematic structural diagram of a high-reflectivity polyester film according to the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific examples. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The performance test method of the reflective polyester film provided by the invention comprises the following steps:

measurement of reflectance: the reflectance of the sample was measured using a Lambda 950 spectrophotometer from Perkin-Elmer, according to GB/T3979-.

Determination of yellow index: the yellowness index of the samples was measured according to GB/T2409-1980 standard using an UltraScanVIS colorimeter from Hunterlab.

Determination of elongation at break: the elongation at break of the sample was measured according to GB/T1040-.

Determination of breakdown voltage: the breakdown voltage (oil) of the sample was measured using an IBV-50 type breakdown voltage tester from Kinco in accordance with GB/T507-.

High pressure accelerated humid heat aging test (PCT)48 h: using a high-pressure accelerated humid heat aging test box, and aging conditions are as follows: aging the sample at 121 deg.C and 100% RH under 0.2MPa for 48 h.