A kind of photovoltaic backplane film and its preparation method

Abstract

The present application discloses a photovoltaic backsheet film and a preparation method thereof. The photovoltaic backsheet film includes a surface layer, a support layer, and a bottom layer. The preparation raw materials of the surface layer include a first reflective filler, the preparation raw materials of the support layer include PET and PTFE, and the first reflective filler is a ZIF-8 confined metal particle material obtained by high-temperature calcination. The photovoltaic backsheet film of the present application has a good reflection effect on infrared light, and also has good anti-yellowing effect and anti-water vapor permeation effect, can better adapt to the harsh outdoor environment, and effectively extends the service life of photovoltaic modules.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cells, and specifically to a photovoltaic backsheet film and a preparation method thereof. Background Art

[0002] Photovoltaic cells, as a key technology for directly converting solar energy into electrical energy, are playing an increasingly important role in the global energy structure. With the growing global demand for renewable energy, photovoltaic cells have been valued for their clean and renewable characteristics. They not only help reduce dependence on fossil fuels and lower greenhouse gas emissions, but also provide power solutions in remote areas and places where the power grid cannot reach. Photovoltaic cells have a wide range of applications, from large-scale ground photovoltaic power stations to residential rooftops and then to portable electronic devices, and their environmental and economic benefits are becoming increasingly significant. In addition, with the progress of technology, the efficiency and cost-effectiveness of photovoltaic cells are also continuously improving, making them an important driving force for the global energy transformation.

[0003] Photovoltaic cells mainly absorb visible light and part of ultraviolet light in sunlight and convert light energy into electrical energy. However, sunlight also contains infrared light, which has low energy and a long wavelength, and makes limited contribution to the electrical energy conversion efficiency of photovoltaic cells. Due to the bandgap width limitation of photovoltaic cell materials, infrared light with a wavelength exceeding 1100 nm cannot effectively excite electrons and thus cannot be directly converted into electrical energy. In addition, infrared light will cause the temperature of the battery panel to rise, affecting the battery performance and lifespan. Therefore, photovoltaic cells need to reflect infrared light to reduce heat loss, keep the battery panel in a cooled state, and thus improve the overall photoelectric conversion efficiency and stability.

[0004] The technical difficulties in the infrared light reflection technology of photovoltaic cells mainly focus on how to effectively manage and utilize infrared light energy. On the one hand, it is necessary to develop materials or coatings with high reflectivity to reduce the thermal impact of infrared light on the battery panel without significantly reducing the absorption of visible light and ultraviolet light. On the other hand, it is necessary to precisely control the temperature of the battery panel to maintain the optimal working state. In addition, the infrared light reflection technology also needs to consider cost-effectiveness and the complexity of the manufacturing process. Summary of the Invention

[0005] The purpose of this application is to provide a material with infrared light reflection performance, anti-yellowing performance, and good water vapor transmission barrier property.

[0006] To achieve the above object, the technical solution adopted in this application is: to provide a photovoltaic backsheet film, including a surface layer, a support layer, and a bottom layer. The preparation raw materials of the surface layer include a first reflective filler, the preparation raw materials of the support layer include PET and PTFE, and the first reflective filler is a high-temperature calcined ZIF-8 confined metal particle material.

[0007] As a preference, the mass ratio of the first reflective filler in the surface layer is 2% - 5%.

[0008] As another preference, the metal particles in the high-temperature calcined ZIF-8 confined metal particle material are any one or a combination of silver, gold, copper, nickel, palladium, and platinum.

[0009] As another preference, the metal particles are any one of silver and nickel, copper and nickel, silver and platinum, and platinum and nickel.

[0010] As another preference, the preparation method of the first reflective filler is as follows: prepare ZIF-8 powder by the hydrothermal method, immerse the ZIF-8 powder in a metal salt solution, add a reducing agent to reduce metal ions, and obtain the ZIF-8 confined metal particle material after drying. Then, perform high-temperature calcination on the ZIF-8 confined metal particle material in an inert gas atmosphere, cool the product and grind it to obtain the first reflective filler.

[0011] As another preference, the raw materials for preparing the support layer are PET and PTFE, and the mass ratio of PET to PTFE is (1:1) - (2:1).

[0012] As another preference, the raw materials for preparing the bottom layer include nano-silica and anti-ultraviolet filler.

[0013] This application also provides a preparation method of a photovoltaic backsheet film, including the following preparation steps: S1: Prepare ZIF-8 powder by the hydrothermal method, immerse the ZIF-8 powder in a metal salt solution, add a reducing agent to reduce metal ions, and obtain the ZIF-8 confined metal particle material after drying. Then, perform high-temperature calcination on the ZIF-8 confined metal particle material in an inert gas atmosphere, cool the product and grind it to obtain the first reflective filler; S2: Mix the first reflective filler, antioxidant, hydrolysis-resistant agent, and PET masterbatch and extrude them in a screw to obtain the surface layer; S3: Mix the PET masterbatch and PTFE masterbatch and extrude them in a screw to obtain the support layer; Mix oxides, the antioxidant, the hydrolysis-resistant agent, anti-ultraviolet filler, and the PET masterbatch and extrude them in a screw to obtain the bottom layer; Melt, shape, and cool the surface layer, the support layer, and the bottom layer on a co-extrusion production line to obtain the photovoltaic backsheet film.

[0014] Further preferably, the temperature of the high-temperature calcination in step S1 is 900 - 1300 °C.

[0015] Further preferably, by mass fraction, the raw materials for preparing the surface layer include: 2% - 5% of the first reflective filler, 1% - 3% of the antioxidant, 1% - 5% of the hydrolysis-resistant agent, and the balance of the PET masterbatch.

[0016] Compared with the prior art, the beneficial effects of the present application are as follows:

[0017] (1) The photovoltaic backsheet film of the present application adds a first reflective filler to the surface layer raw material, and can obtain a good infrared light reflectivity;

[0018] (2) In the photovoltaic backsheet film of the present application, the support layer is selected as a composite of PET and PFTE materials, and can obtain good yellowing resistance and excellent water vapor permeability;

[0019] (3) The photovoltaic backsheet film of the present application adds nano-silicon dioxide oxide and anti-ultraviolet filler to the preparation raw material of the bottom layer, endows the photovoltaic backsheet with excellent anti-ultraviolet effect and yellowing resistance, and prolongs the service life of the photovoltaic backsheet film. Specific Embodiments

[0020] Next, in combination with specific embodiments, the present application will be further described. It should be noted that, on the premise of no conflict, any combination can be formed between the following described embodiments or technical features to form a new embodiment.

[0021] The terms "comprising" and "having" in the specification and claims of the present application and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units is not necessarily 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.

[0022] The present application provides a photovoltaic backsheet film, which includes a surface layer, a support layer and a bottom layer, and both the upper surface layer and the lower surface layer are white, so that the photovoltaic backsheet film of the present application as a whole presents white, which is convenient for subsequently stacking any outer layer film to obtain a photovoltaic backsheet of any color.

[0023] The preparation raw material of the surface layer of the photovoltaic backsheet film of the present application includes a first reflective filler, the first reflective filler is a ZIF-8 confined metal particle material calcined at high temperature, and the support layer is a composite material of PET and PTFE. The preparation raw material of the bottom layer of the photovoltaic backsheet film of the present application includes an oxide and an anti-ultraviolet filler.

[0024] ZIF-8 has pores with a diameter of about 11.6 Å and is characterized by being interconnected through six-ring windows (3.5 Å) and four-ring windows. By the method of liquid phase impregnation combined with in-situ reduction, nano-metal particles can be uniformly dispersed in the ZIF-8 carrier, and the loading of metal particles does not change the morphology and size of ZIF-8, and does not change the stability of ZIF-8.

[0025] The ZIF-8-confined metal particles can better solve the problem of the dispersion of metal particles in PET and do not affect the infrared reflection performance of the metal particles. Dispersing the ZIF-8 with cavity-confined metal particles uniformly in PET can solve the agglomeration problem of metal particles in PET. When applied to the base film of a photovoltaic backplane, a photovoltaic backplane with strong infrared reflectivity can be obtained, thereby avoiding the temperature rise of the photovoltaic backplane and improving its photoelectric conversion efficiency.

[0026] After high-temperature calcination of the ZIF-8-confined metal particle material, a porous carbon material containing metal particles is obtained, which has a good specific surface area and excellent electrochemical, adsorption, and photocatalytic properties.

[0027] The photovoltaic backplane film of this application has a good reflection effect on infrared light, and has good anti-yellowing and anti-water vapor permeation effects, can better adapt to the harsh outdoor environment, and effectively extends the service life of photovoltaic modules.

[0028] In some embodiments, in the surface layer raw material, by mass fraction, the addition amount of the first reflection filler is 2% - 5%.

[0029] In some embodiments, the metal particles confined in the internal pores of ZIF-8 are any one or a combination of silver, gold, copper, nickel, palladium, and platinum.

[0030] In some embodiments, two metal particles are simultaneously confined in the internal pores of ZIF-8, which can be any one group of silver and nickel, copper and nickel, silver and platinum, and platinum and nickel.

[0031] In some embodiments, the preparation method of the first reflection filler is: preparing ZIF-8 material by the hydrothermal method, then impregnating the ZIF-8 material in a metal salt solution, stirring for a period of time, and then reducing the metal particles with a reducing agent to obtain the ZIF-8-confined metal particle material, and calcining this material at high temperature in an inert atmosphere to obtain the ZIF-8-confined metal particle material after high-temperature calcination.

[0032] In some embodiments, the temperature of high-temperature calcination is 900 - 1300 °C.

[0033] In some embodiments, the preparation raw materials of the surface layer include: the first reflection filler, antioxidant, anti-hydrolysis agent, and PET.

[0034] In some embodiments, the preparation raw materials of the support layer are PET and PTFE, and the mass ratio of PET to PTFE is (1:1) - (2:1).

[0035] In some embodiments, the raw materials for preparing the bottom layer include: nano silicon dioxide, antioxidant, anti-hydrolysis agent, anti-ultraviolet filler and PET. In some preferred embodiments, the particle size of the nano silicon dioxide is 30-60 nm.

[0036] In some embodiments, the anti-hydrolysis agent is any one or more combinations of oxazoline compounds, epoxy compounds, aromatic carbodiimide, aliphatic carbodiimide, and polycarbodiimide.

[0037] In a more preferred embodiment, the anti-hydrolysis agent is an aromatic carbodiimide. Aromatic carbodiimide anti-hydrolysis stabilizers react chemically with hydrolysis products such as carboxylic acid or water to inhibit catalytic hydrolysis degradation and extend service life. In addition, aromatic carbodiimide also has excellent antioxidant, heat resistance and flame resistance, greatly improving the weather resistance and aging resistance of the backsheet film, thereby ensuring a higher reflectivity of the photovoltaic backsheet to sunlight.

[0038] In some embodiments, the antioxidant is an antioxidant that is any one or more of an amine antioxidant, a quinoline derivative antioxidant, a hindered phenol antioxidant, a phosphite antioxidant, a thioester antioxidant, a hydroperoxide decomposer, and a heavy metal ion passivator.

[0039] In a more preferred embodiment, the antioxidant is a hindered phenol and a phosphite antioxidant, and the combination of the two produces a synergistic effect to improve the weather resistance and discoloration resistance of the backsheet film.

[0040] In some embodiments, the anti-ultraviolet filler is any one or a combination of titanium dioxide, benzophenone, salicylate, benzotriazole, triazine, benzoic acid, amino acid, benzoimide and nano zinc oxide.

[0041] The present application also provides a method for preparing a photovoltaic backplane film, comprising the following preparation steps:

[0042] S1: preparing ZIF-8 powder by hydration method, immersing the ZIF-8 powder in a metal salt solution, adding a reducing agent to reduce metal ions to metal elements, and obtaining ZIF-8 confined metal particle material after drying; calcining the ZIF-8 confined metal particle material at high temperature under an inert gas atmosphere, cooling the product and grinding it to obtain a first reflective filler;

[0043] S2: mixing the first reflective filler, the antioxidant, the anti-hydrolysis agent and the PET masterbatch and extruding the mixture in a screw rod to obtain a surface layer;

[0044] S3: Mix the PET masterbatch and the PTFE masterbatch and extrude them in a screw rod to obtain a support layer; mix the oxide, antioxidant, hydrolysis inhibitor, ultraviolet light resistant filler and PET masterbatch and extrude them in a screw rod to obtain a bottom layer; melt, shape and cool the surface layer, the support layer and the bottom layer on a coextrusion production line to obtain the photovoltaic backsheet film of the present application.

[0045] In some embodiments, the temperature of the high-temperature calcination in step S1 is 900-1300 °C.

[0046] In some embodiments, by mass fraction, the raw materials for preparing the surface layer include: 2%-5% first reflective filler, 1%-3% antioxidant, 1%-5% hydrolysis inhibitor and the balance PET masterbatch. In some embodiments, the raw materials for preparing the support layer are PET masterbatch and PTFE masterbatch, and the mass ratio of PET masterbatch to PTFE masterbatch is (1:1)-(2:1). In some embodiments, by mass fraction, the raw materials for preparing the bottom layer include: 1%-3% oxide, 1%-3% antioxidant, 1%-5% hydrolysis inhibitor, 1%-2% ultraviolet light resistant filler and the balance PET masterbatch.

[0047] The preparation method of the photovoltaic backsheet film of the present application is simple, with a high success rate, and the prepared photovoltaic backsheet has good performance and a long service life, and has certain economic adaptability.

[0048] Example 1

[0049] Prepare a photovoltaic backsheet film according to the following preparation steps:

[0050] S1: Dissolve 4.94 mmol of Zn(NO3)2·6H2O in 100 mL of methanol to obtain solution a, dissolve 39.62 mmol of 2-methylimidazole in 100 mL of methanol to obtain solution b, quickly pour solution a into solution b, stir at room temperature for 1 h, centrifuge the generated precipitate and wash it with methanol 3 times, dry the washed precipitate at 60 °C for 12 h to obtain a white powder, and the white powder is ZIF-8;

[0051] Dissolve 49.52 mg of AgNO3 in 20 mL of deionized water, then add 22.58 mg of polyvinyl alcohol (PVA), stir at room temperature for 1 h, then add 200 mg of activated ZIF-8 to the solution, continue to stir for 2 h, under the condition of an ice-water bath, add 4.8 mL of NaBH4 dropwise to the solution, continue to stir the solution for 5 h after the addition is completed, centrifuge the generated precipitate and wash it with deionized water 3 times, and dry it at 60 °C for 12 h to obtain the Ag@ZIF-8 material;

[0052] The Ag@ZIF-8 material is ground and calcined at a high temperature under the protection of an inert gas. The calcination temperature is set at 900 - 1300 °C. After cooling to room temperature, the product is taken out, washed, dried and ground to obtain the Ag / Zn@C material, which is the first reflective filler;

[0053] S2: By mass, 5% of the first reflective filler, 0.5% of the antioxidant, 1% of the hydrolysis inhibitor and the balance of PET masterbatch are mixed in a high-speed mixer and extruded through a screw extruder. The temperature of the extruder is set at 220 °C, and the rotation speed of the screw extruder is set at 15 r / min. After melting, extruding and plasticizing the raw materials, the surface layer is obtained;

[0054] S3: The PET masterbatch and the PTFE masterbatch are melt-blended in a mass ratio of 2:1 and sent into an injection molding machine to be injection molded into a sheet-shaped specimen under a pressure of 50 MPa and a temperature of 200 °C to obtain the support layer;

[0055] By mass, 3% of nano-silica, 0.5% of the antioxidant, 1% of the hydrolysis inhibitor, 1% of the ultraviolet-resistant filler and the balance of PET masterbatch are mixed in a high-speed mixer and extruded through a screw extruder. The temperature of the extruder is set at 220 °C, and the rotation speed of the screw extruder is set at 15 r / min. After melting, extruding and plasticizing the raw materials, the bottom layer is obtained;

[0056] The surface layer, the support layer and the bottom layer are transported to a co-extrusion production line of the backplane and extruded through a die to obtain a sheet-shaped melt. The sheet-shaped melt is cooled and shaped by a cooling roller and then wound or cut to obtain the photovoltaic backplane film of the present application.

[0057] Example 2

[0058] In step S1, the silver salt is replaced with a corresponding mass of copper salt. After synthesizing the Cu@ZIF-8 material, it is calcined to obtain the Cu / Zn@C material as the first reflective material. Other preparation methods are the same as those in Example 1.

[0059] Example 3

[0060] In step S1, the silver salt is replaced with a corresponding mass of nickel salt. After synthesizing the Ni@ZIF-8 material, it is calcined to obtain the Ni / Zn@C material as the first reflective material. Other preparation methods are the same as those in Example 1.

[0061] Example 4

[0062] In step S1, the silver salt is replaced with a corresponding mass of nickel salt and silver salt. After synthesizing the Ag / Ni@ZIF-8 material, it is calcined to obtain the Ag / Ni / Zn@C material as the first reflective material. Other preparation methods are the same as those in Example 1.

[0063] Example 5

[0064] In step S1, the silver salt is replaced with corresponding masses of nickel salt and copper salt. After synthesizing the Ni / Cu@ZIF-8 material, it is calcined to obtain the Ni / Cu / Zn@C material as the first reflective material, and other preparation methods are kept consistent with the preparation steps in Example 1.

[0065] Comparative Example 1

[0066] The ZIF-8 material is prepared in step S1. After calcining the ZIF-8, it is mixed with silver powder to obtain Zn@C+Ag as the reflective filler. This reflective filler is added to the surface layer material instead of the first reflective material of this application, and other preparation steps are kept consistent with the steps in Example 1 to prepare the photovoltaic backsheet film of Comparative Example 1.

[0067] Comparative Example 2

[0068] The ZIF-8 material is prepared in step S1. After calcining the ZIF-8, it is mixed with copper powder to obtain Zn@C+Cu as the reflective filler. This reflective filler is added to the surface layer material instead of the first reflective material of this application, and other preparation steps are kept consistent with the steps in Example 1 to prepare the photovoltaic backsheet film of Comparative Example 2.

[0069] Comparative Example 3

[0070] In step S3, the PET masterbatch and PTFE masterbatch are no longer used in combination. Instead, all PET masterbatch is used for melting to prepare the support layer, and other preparation steps are kept consistent with the preparation steps in Example 1 to prepare the photovoltaic backsheet film of Comparative Example 3.

[0071] Comparative Example 4

[0072] The ZIF-8 material is prepared in step S1. After calcining the ZIF-8, it is mixed with nickel powder and copper powder together to obtain Zn@C+Ni+Cu as the reflective filler. This reflective filler is added to the surface layer material instead of the first reflective material of this application, and other preparation steps are kept consistent with the steps in Example 1 to prepare the photovoltaic backsheet film of Comparative Example 4.

[0073] Comparative Example 5

[0074] The ZIF-8 material is prepared in step S1, and silver and nickel are confined in the ZIF-8 material to prepare the Ag / Ni@ZIF-8 material. The Ag / Ni@ZIF-8 material is not subjected to high-temperature calcination, and it is used as the reflective filler to be added to the surface layer material instead of the first reflective material of this application. Other preparation steps are kept consistent with the steps in Example 4 to prepare the photovoltaic backsheet film of Comparative Example 5.

[0075] Performance Detection

[0076] The base films prepared in Examples 1 to 5 and Comparative Examples 1 to 4 were subjected to the following performance tests, and the test results were recorded in Table 1.

[0077] 1. Reflectance

[0078] The test method refers to the spectrophotometer method with an integrating sphere in Standard GB / T 29848, "Ethylene-vinyl acetate copolymer (EVA) film for encapsulation of photovoltaic modules". The test instrument is an ultraviolet-visible spectrophotometer, and the test conditions are 780 - 1100 nm.

[0079] 2. Yellowing index

[0080] The test method refers to Standard GB / T 2409, "Test method for yellowing index of plastics"; the specimen size is 100 x 100 mm; the test conditions are 25 °C and 50% RH.

[0081] 3. Water vapor transmission rate test

[0082] After hydrolysis treatment under the condition of 85% relative humidity, the water vapor transmission test was carried out according to the test method in BG / T 26253-2010.

[0083] Table 1 Performance test results of each example and each comparative example

[0084]

[0085] Analyzing the performance test results in Table 1, it can be seen that the photovoltaic backplane films prepared in each example of this application all have good infrared light reflectance, low yellowing index, and poor water vapor permeability, and can better protect photovoltaic modules outdoors and extend the service life of photovoltaic modules.

[0086] Analyzing the performance test results of Examples 1 to 5, the reflectance effect of confining two metal particles simultaneously in the ZIF-8 channels after high-temperature calcination is better than that of confining only one metal particle. Among them, the material obtained by confining silver and nickel in ZIF-8 and then calcining at high temperature has the best infrared light reflectivity, and has good anti-yellowing performance and anti-water vapor transmission rate.

[0087] Analyzing the performance test results of Example 1 and Comparative Examples 1, 2, and 4, when metal particles are confined in the pore structure of ZIF-8 to obtain a supported material and then the material is calcined, the infrared reflectance effect of the prepared photovoltaic backplane film is better than that of the mixture of calcined ZIF-8 material and metal powder.

[0088] Similarly, Comparative Example 5 uses ZIF-8 to confine both silver and nickel metal particles at the same time, but does not perform calcination and directly adds them to the preparation of the photovoltaic backsheet film material. The obtained infrared reflectivity effect is not as good as that of Example 4 after loading and calcination.

[0089] Therefore, high-temperature calcination after loading metal particles in the ZIF-8 channels is an important step, which has a good promoting effect on the infrared light reflectivity. It is speculated that the reason may be that the internal channels of ZIF-8 are loaded with metal particles, which can better improve the dispersion of metal particles. After high-temperature calcination, ZIF-8 decomposes and carbonizes. ZIF-8 may be carbonized into porous carbon with a graphite phase structure, and metal particles are dispersed in the structure. Therefore, it can better improve the infrared light reflectivity, anti-yellowing performance and water vapor permeability of the photovoltaic backsheet film.

[0090] Analyze the performance test results of Example 1 and Comparative Example 3. The raw materials for preparing the support layer are changed, which significantly reduces the anti-yellowing performance and water vapor permeability of the photovoltaic backsheet film. Therefore, when using the material obtained by calcining after loading metal particles with ZIF-8 as the first reflective filler, a PET and PTFE composite material needs to be used as the intermediate barrier layer in the intermediate support layer to block the water vapor from passing through and extend the service life of the photovoltaic module.

[0091] In summary, for the photovoltaic backsheet film of the present application, a first reflective filler is added to the preparation raw materials of the surface layer, a PET and PTFE composite material is used in the support layer, and oxides and anti-ultraviolet fillers are added to the preparation raw materials of the bottom layer. The prepared photovoltaic backsheet film can obtain good infrared light reflectivity, anti-yellowing and water vapor permeability resistance.

[0092] The basic principles, main features and advantages of the present application have been described above. Those skilled in the art of this industry should understand that the present application is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of the present application. Without departing from the spirit and scope of the present application, the present application will have various changes and improvements, and these changes and improvements all fall within the scope of the present application claimed. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. A photovoltaic backsheet film, characterized in that: It includes a surface layer, a support layer and a bottom layer, wherein the raw material for preparing the surface layer includes a first reflective filler, the raw material for preparing the support layer includes PET and PTFE, the first reflective filler is a ZIF-8 confined metal particle material calcined at a high temperature of 900-1300°C in an inert gas atmosphere; the mass proportion of the first reflective filler in the surface layer is 2%-5%; the metal particles in the ZIF-8 confined metal particle material calcined at a high temperature are any one of silver, gold, copper, nickel, palladium and platinum, or a combination of more than one thereof.

2. The photovoltaic backsheet film according to claim 1, characterized in that: The metal particles are any one of silver and nickel, copper and nickel, silver and platinum, and platinum and nickel.

3. The photovoltaic backsheet film according to claim 1, characterized in that: The preparation method of the first reflective filler is: prepare ZIF-8 powder by hydration method, immerse the ZIF-8 powder in a metal salt solution, add a reducing agent to reduce the metal ions, obtain ZIF-8 confined metal particle material after drying, calcine the ZIF-8 confined metal particle material at high temperature under an inert gas atmosphere, cool the product and grind it to obtain the first reflective filler.

4. The photovoltaic backsheet film according to claim 1, characterized in that: The supporting layer is prepared from PET and PTFE, and the mass ratio of the PET to the PTFE is (1:1) to (2:1).

5. The photovoltaic backsheet film according to claim 1, characterized in that: The raw materials for preparing the bottom layer include nano silicon dioxide and anti-ultraviolet filler.

6. A method for preparing a photovoltaic backplane film, characterized in that: The method comprises the following preparation steps: S1: preparing ZIF-8 powder by hydration method, immersing the ZIF-8 powder in a metal salt solution, adding a reducing agent to reduce metal ions, and obtaining a ZIF-8 confined metal particle material after drying; calcining the ZIF-8 confined metal particle material at high temperature under an inert gas atmosphere, cooling the product and grinding it to obtain a first reflective filler; the metal particles in the ZIF-8 confined metal particle material calcined at high temperature are any one or a combination of multiple of silver, gold, copper, nickel, palladium, and platinum; the temperature of the high temperature calcination is 900-1300°C; S2: mixing the first reflective filler, antioxidant, anti-hydrolysis agent and PET masterbatch and extruding the mixture in a screw to obtain a surface layer; S3: The PET masterbatch and the PTFE masterbatch are mixed and extruded in a screw rod to obtain a support layer; the oxide, the antioxidant, the anti-hydrolysis agent, the anti-ultraviolet filler and the PET masterbatch are mixed and extruded in a screw rod to obtain a bottom layer; the surface layer, the support layer and the bottom layer are melted, shaped and cooled on a co-extrusion production line to obtain the photovoltaic backplane film.

7. The preparation method according to claim 6, characterized in that: Calculated by mass fraction, the raw materials for preparing the surface layer include: 2% to 5% of the first reflective filler, 1% to 3% of the antioxidant, 1% to 5% of the anti-hydrolysis agent and the balance of the PET masterbatch.

Images