CN118493984A - Super Bai Juzhi base film for high-reflection black backboard, preparation method and application thereof - Google Patents

Abstract

The present application discloses an ultra-white polyester base film for a high-reflective black backplane, comprising a first surface layer, an ultra-white support layer, and a second surface layer, wherein the ultra-white support layer is made of PET and PP, a second reflective filler is dispersed in the second surface layer, and the second reflective filler is nano-silicon dioxide, and a first reflective filler is dispersed in the first surface layer, and the first reflective filler is ZIF-8 confined metal particles. The ultra-white polyester base film for a high-reflective black backplane of the present application can improve the infrared light reflection performance and anti-yellowing performance of the polyester base film, and is used in a photovoltaic backplane.

Description

Ultra-white polyester base film for high-reflective black backboard, preparation method and application thereof

Technical Field

The present application relates to the field of new material technology, and specifically to an ultra-white polyester base film for a high-reflective black backplane, a preparation method and an application thereof.

Background Art

Photovoltaic cell modules mainly include stacked EVA, adhesive layer, cell, adhesive layer and back sheet, which are encapsulated by frames on all sides, and the photovoltaic back sheet is mainly used to support and fix the cell and isolate it from environmental erosion. Black solar cell back sheet is a special type of photovoltaic module. Its main advantage is that the black appearance is more suitable for occasions such as roofs and buildings that require aesthetics.

The black surface of the black photovoltaic backplane easily absorbs sunlight and converts it into heat energy. On the one hand, it causes the photovoltaic backplane to heat up seriously, which will reduce the service life of the photovoltaic backplane. On the other hand, the black photovoltaic backplane absorbs sunlight, and this part of the light cannot be effectively used, thereby greatly reducing the photoelectric conversion efficiency of the component.

Summary of the invention

The purpose of this application is to improve the infrared light reflection performance of the ultra-white polyester base film for photovoltaic backplanes.

In order to achieve the above objectives, the technical solution adopted in the present application is: to provide an ultra-white polyester base film for a high-reflective black backplane, comprising a first surface layer, an ultra-white support layer and a second surface layer, the ultra-white support layer is made of PET and PP, a second reflective filler is dispersed in the second surface layer, and the second reflective filler is nano-silicon dioxide, and a first reflective filler is dispersed in the first surface layer, and the first reflective filler is ZIF-8 confined metal particles.

As a preference, the content of the first reflective filler is 1% to 3%.

As another preference, the content of the first reflective filler is 1%.

As another preference, the first reflective filler is metal particles confined inside ZIF-8, and the metal particles are any one or more combinations of platinum, nickel, palladium and silver.

As another preferred embodiment, the first reflective filler is metal particles confined inside ZIF-8, and the metal particles are nickel and silver; or, the first reflective filler is metal particles confined inside ZIF-8, and the metal particles are platinum and silver; or, the first reflective filler is metal particles confined inside ZIF-8, and the metal particles are platinum and nickel; or, the first reflective filler is metal particles confined inside ZIF-8, and the metal particles are palladium and silver.

As another preference, the particle size of the nano-silicon dioxide is 40 to 50 nm.

As another preference, the thickness of the first surface layer is 60-80 μm, the thickness of the ultra-white support layer is 250-350 μm, and the thickness of the second surface layer is 25-35 μm.

Provided is a method for preparing an ultra-white polyester base film for a high-reflective black backplane, comprising the following preparation steps: S1: using zinc nitrate and 2-methylimidazole to prepare ZIF-8, then adding the ZIF-8 to a salt solution of metal particles and uniformly mixing to obtain a mixed solution, adding a reducing agent to the mixed solution to reduce metal ions to metal elements, and obtaining a first reflective filler after precipitation, filtering, drying and washing, wherein the salt solution of the metal particles is any one or more combinations of platinum salts, nickel salts, palladium salts and silver salts;

S2: The first reflective filler is mixed with PET masterbatch and then injection molded to obtain a first surface layer; S3: The PET masterbatch and PP masterbatch are mixed and then injection molded to obtain an ultra-white support layer; the nanoporous silica is mixed with PET masterbatch and then injection molded to obtain a second surface layer; S4: The first surface layer, the ultra-white support layer and the second surface layer are co-extruded to obtain the ultra-white polyester base film for the high-reflective black backplane.

As another preference, the salt solution of the metal particles is a mixture of nickel salt and silver salt, wherein the molar ratio of nickel ions to silver ions is 1:1; or, the salt solution of the metal particles is a mixture of platinum salt and silver salt, wherein the molar ratio of platinum ions to silver ions is 1:1; or, the salt solution of the metal particles is a mixture of platinum salt and nickel salt, wherein the molar ratio of platinum ions to nickel ions is 1:1; or, the salt solution of the metal particles is a mixture of palladium salt and silver salt, wherein the molar ratio of palladium ions to silver ions is 1:1.

Provided is a photovoltaic cell, comprising, from top to bottom, a photovoltaic backplane, a packaging material, a battery cell, a packaging material and a packaging glass, wherein the photovoltaic backplane comprises any of the above-mentioned ultra-white polyester base films for a high-reflective black backplane, or is prepared by any of the above-mentioned preparation methods, and the first surface layer is arranged on a side away from the battery cell.

Compared with the prior art, the beneficial effects of this application are:

(1) The present application uses ZIF-8 confined metal particles as the first reflective filler added to PET to improve the infrared light reflection performance of the polyester base film;

(2) The present application uses ZIF-8 confined metal particles as the first reflective filler added to PET, which can enhance the anti-yellowing ability of the polyester base film.

DETAILED DESCRIPTION

Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

The terms "including" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

The present application provides an ultra-white polyester base film for a high-reflective black backplane and a preparation method thereof, which comprises a first surface layer, an ultra-white support layer and a second surface layer, wherein the first surface layer, the ultra-white support layer and the second surface layer are all white.

The first surface layer is PET uniformly dispersed with a first reflective filler.

The first reflective filler is ZIF-8 confined metal particles.

Metal organic frameworks (MOFs) are a new type of material, also known as metal organic complex polymers. They are a type of porous functional material with a periodic network structure formed by inorganic structural units (such as metal ions or clusters) and organic ligands (such as carboxylic acids, phosphates or nitrogen-containing ligands, etc.) connected by coordination bonds. Compared with traditional inorganic porous materials, MOFs materials have incomparable excellent properties of inorganic porous materials such as zeolites, activated carbon, and carbon nanotubes. Their micropore volume is several times higher than that of the above-mentioned porous materials, and they have the characteristics of variable pores and stable chemical structures. These excellent properties make MOFs materials have great application prospects in gas storage, adsorption and separation of water pollutants, gas catalysis, etc.

As a popular organic-inorganic hybrid material, MOFs are usually synthesized by solvothermal method or microwave-assisted synthesis method, which can efficiently construct MOFs with specific structures under mild conditions. The structure of MOFs can be precisely controlled by selecting different metal ions and organic ligands, thereby achieving fine adjustment of material properties. For example, by changing the type of metal ions or the connection method of organic ligands, the pore size, topological structure and surface functionalization degree of MOFs can be adjusted.

Zeolitic imidazolate frameworks (ZIFs) are an important subclass of metal-organic frameworks (MOFs). They have a structure similar to that of aluminosilicate zeolites, combining the advantages of both zeolites and MOFs. They not only have strong thermal and chemical stability, but also have high specific surface area and high pore volume. ZIFs are ordered porous materials formed by metal zinc ions and 2-methylimidazole connected by coordination bonds. They are widely used in many fields, including gas adsorption and separation, catalytic reactions, sensors, microelectronic devices, drug carriers, 3D printing, and fluorescence detection.

ZIF-8 is a porous crystalline material formed by the self-assembly of Zn(II) and 2-methylimidazole, and belongs to the family of zeolitic imidazolate frameworks (ZIFs). ZIF-8 has the characteristics of tunable pore size, highly stable structure and catalytic activity. It can be synthesized by solvothermal method using zinc nitrate hexahydrate as zinc source and 2-methylimidazole as organic ligand. The crystal structure of ZIF-8 is based on seven different aluminosilicate zeolite networks, in which tetrahedral Si(Al) and bridging O are replaced by transition metal ions and imidazole framework, respectively.

ZIF-8 exhibits excellent chemical and thermal stability and can resist boiling alkaline water and organic solvents. In addition, ZIF-8 also has permanent porosity (Langmuir specific surface area is ^1810m2 /g) and high thermal stability (up to 550℃). These characteristics make ZIF-8 have a wide range of application potentials in gas adsorption, separation, catalysis, biomedicine and other fields.

The infrared reflectivity of a material is affected by many factors, including but not limited to the material's composition, density, doping elements, particle size and morphology, surface treatment, and microstructure.

The infrared reflectivity of metal particles is affected by many factors, including particle size, shape, matrix refractive index, coating form, and particle arrangement. First, the size and shape of the particles have a significant effect on their infrared reflectivity.

First, the size and shape of the particles have a significant effect on the infrared reflectivity. Small metal particles absorb more strongly in the infrared region than large metal particles, which is related to surface plasmon resonance. In addition, the optical cross-section and scattering intensity of metal particles in different refractive index matrices will be affected, so the refractive index of the matrix is an important factor affecting the infrared reflectivity of metal particles.

The arrangement of metal particles also affects their infrared reflectivity. For example, a coating containing parallel-arranged flake metal ions has a lower emissivity, and this arrangement is affected by the solid content, size, coating thickness and resin absorption characteristics of the particles.

ZIF-8 has a diameter of approximately The hole and the six-ring window Taking advantage of the interconnected characteristics of the four-ring windows, nanometal particles can be evenly dispersed in the ZIF-8 carrier through liquid phase impregnation combined with in situ reduction. Moreover, the loading of metal particles does not change the morphology and size of ZIF-8, nor does it change the stability of ZIF-8.

ZIF-8 confined metal particles can effectively solve the problem of metal particle dispersion in PET without affecting the infrared reflection performance of metal particles. Evenly dispersing ZIF-8 with hollow confined metal particles in PET can solve the problem of metal particle agglomeration in PET. The evenly dispersed first reflective filler makes the first surface layer have good infrared reflection ability. When used in the photovoltaic backplane base film, a photovoltaic backplane with strong infrared reflection can be obtained, thereby avoiding the heating of the photovoltaic backplane and improving its photoelectric conversion efficiency.

In the ultra-white polyester base film for high-reflective black backplane of the present application, the reflective filler is ZIF-8 confined metal particles, wherein the metal particles include but are not limited to platinum, nickel, palladium, and silver.

In some preferred embodiments, ZIF-8 confines two different metal particles, using a diameter of Holes and six-ring windows It is beneficial to increase the loading rate of metal particles, and two different metal particles can be compounded to improve the infrared reflectivity of the first surface.

In some preferred embodiments, the content of the first reflective filler is 1% to 3%.

The ultra-white support layer is a mixture of PET and PP. When PET is used outdoors for a long time, the water vapor and oxygen in the environment will corrode the back sheet, causing it to lose its protection and support functions for the solar cells. PP resin has excellent barrier properties to water vapor and has a good barrier effect on the hydrolysis of PET.

The second surface layer of the ultra-white polyester base film for the high-reflective black backboard of the present application is PET in which a second reflective filler is uniformly dispersed. The second reflective filler is nano-silicon dioxide, and the particle size of the nano-silicon dioxide is 40 to 50 nm.

The second surface layer is usually arranged on the side of the photovoltaic backplane base film facing the ground. Arranging a second reflective filler in the second surface layer can prevent the infrared rays reflected by the ground from causing the photovoltaic backplane to heat up. However, the infrared rays reflected by the ground are small after all. Therefore, a relatively cheap second reflective filler is selected, which is both practical and cost-effective.

In some preferred embodiments, the first reflective filler is a ZIF-8 material that simultaneously confines two metal particles.

In a preferred embodiment, the first reflective filler is Ni, Ag@ZIF-8 or Pt, Ag@ZIF-8 or Ni, Pt@ZIF-8 or Pd, Ag@ZIF-8.

By using different pores of ZIF-8, two kinds of metal particles can be confined, which can improve the infrared reflection effect of the polyester base film.

In some preferred embodiments, the thickness of the first surface layer is 60-80 μm, the thickness of the ultra-white support layer is 250-350 μm, and the thickness of the second surface layer is 25-35 μm.

The present application provides a method for preparing an ultra-white polyester base film for a high-reflective black backplane, comprising the following preparation steps:

S1: ZIF-8 is prepared by using zinc nitrate and 2-methylimidazole, and then ZIF-8 is added to a metal salt solution and mixed evenly to obtain a mixed solution, a reducing agent is added to the mixed solution to reduce the metal ions to a metal element, and the precipitate is filtered, dried and washed to obtain a first reflective filler;

S2: The first reflective filler is mixed with the PET masterbatch and then injection molded to obtain the first surface layer;

S3: Mixing the PET masterbatch with the PP masterbatch and then performing injection molding to obtain an ultra-white support layer; mixing the nanoporous silica with the PET masterbatch and then performing injection molding to obtain a second surface layer;

S4: The first surface layer, the ultra-white support layer and the second surface layer are co-extruded to obtain the ultra-white polyester base film for the high-reflective black backplane of the present application.

The present application also provides a photovoltaic cell, which includes, from top to bottom, a photovoltaic backplane, a packaging material, a battery cell, a packaging material and a packaging glass, wherein the photovoltaic backplane is made of the above-mentioned ultra-white polyester base film for the high-reflective black backplane, and the first surface layer of the ultra-white polyester base film for the high-reflective black backplane is arranged on the side away from the battery cell.

Example 1

The present application prepares an ultra-white polyester base film for a high-reflective black backplane, wherein the content of the first reflective filler is 1%, and the first reflective filler is Ni@ZIF-8, and the preparation steps are as follows:

S1: 4.94 mmol of Zn(NO ₃ ) ₂ ·6H ₂ O was dissolved in 100 mL of methanol to obtain solution a, 39.62 mmol of 2-methylimidazole was dissolved in 100 mL of methanol to obtain solution b, solution a was quickly poured into solution b, and stirred at room temperature for 1 h. The generated precipitate was centrifuged and washed with methanol for 3 times. The washed precipitate was dried at 60°C for 12 h to obtain a white powder, which was ZIF-8;

49.52 mg of Ni(NO ₃ ) ₂ ·6H ₂ O was dissolved in 20 mL of deionized water, and then 22.58 mg of polyvinyl alcohol (PVA) was added. After stirring at room temperature for 1 h, 200 mg of activated ZIF-8 was added to the solution and stirred for 2 h. Under ice-water bath conditions, 4.8 mL of NaBH ₄ was added dropwise to the solution. After the addition was completed, the solution was stirred for 5 h. The generated precipitate was centrifuged and washed with deionized water for 3 times, and dried at 60°C for 12 h to obtain Ni@ZIF-8 material as the first reflective filler.

S2: The first reflective filler and the PET masterbatch are mixed at a high speed, the mass proportion of the first reflective filler being 1%, and injection molded into a sheet sample by an injection molding machine at a pressure of 50 MPa and a temperature of 268°C to obtain a first surface layer, and the thickness of the first surface layer is controlled to be 60 to 80 μm.

S3: melt-blending the PET masterbatch and the PP masterbatch in a mass ratio of 2:1, and feeding the mixture into an injection molding machine for injection molding into a sheet sample at a pressure of 50 MPa and a temperature of 200° C. to obtain an ultra-white support layer, and controlling the thickness of the ultra-white support layer to be 250 to 350 μm;

Nano-silicon dioxide with a particle size of 40 nm is mixed with PET masterbatch at high speed, wherein the mass proportion of nano-silicon dioxide is 1%, and is sent to an injection molding machine and injection molded into a sheet pattern at a pressure of 50 MPa and a temperature of 250°C to obtain a second surface layer, and the thickness of the second surface layer is controlled to be 25 to 35 μm.

S4: The first surface layer, the ultra-white support layer and the second surface layer are transported to the backboard co-extrusion production line and extruded through a mold to obtain a sheet melt. The sheet melt is cooled and shaped by a cooling roller, and then rolled or cut to obtain the ultra-white polyester base film for the high-reflective black backboard of the present application.

Example 2

In this embodiment, an ultra-white polyester base film for a high-reflective black backplane is prepared, wherein the content of the first reflective filler is 2%, and the first reflective filler is Ni@ZIF-8.

The difference from the preparation method in Example 1 is that the mass proportion of the first reflective filler in step S2 is 2%.

Example 3

In this embodiment, an ultra-white polyester base film for a high-reflective black backplane is prepared, wherein the content of the first reflective filler is 3%, and the first reflective filler is Ni@ZIF-8.

The difference from the preparation method in Example 1 is that the mass proportion of the first reflective filler in step S2 is 3%.

Example 4

In this embodiment, an ultra-white polyester base film for a high-reflective black backplane is prepared, wherein the content of the first reflective filler is 1%, and the first reflective filler is Ag@ZIF-8.

The difference from the preparation method in Example 1 is that in step S1, the nickel salt is replaced by a silver salt.

Example 5

In this embodiment, an ultra-white polyester base film for a high-reflective black backplane is prepared, wherein the content of the first reflective filler is 1%, and the first reflective filler is Pt@ZIF-8.

The difference from the preparation method in Example 1 is that in step S1, the nickel salt is replaced by a platinum salt.

Example 6

In this embodiment, an ultra-white polyester base film for a high-reflective black backplane is prepared, wherein the content of the first reflective filler is 1%, and the first reflective filler is Ni, Ag@ZIF-8.

The difference from the preparation method in Example 1 is that in step S1, the nickel salt is replaced by a mixture of nickel salt and silver salt, wherein the molar ratio of nickel ions to silver ions is 1:1.

Example 7

In this embodiment, an ultra-white polyester base film for a high-reflective black backplane is prepared, wherein the content of the first reflective filler is 1%, and the first reflective filler is Pt, Ag@ZIF-8.

The difference from the preparation method in Example 1 is that in step S1, the nickel salt is replaced by a mixture of platinum salt and silver salt, wherein the molar ratio of platinum ions to silver ions is 1:1.

Comparative Example 1

A polyester base film was prepared. The difference from Example 1 was that white ZIF-8 powder was prepared and added into PET as a reflective filler to prepare the first surface layer of Comparative Example 1. The content of ZIF-8 was 1%.

Comparative Example 2

A polyester base film was prepared. The difference from Example 1 was that nano nickel was added as a reflective filler into PET to prepare the first surface layer of Comparative Example 2, and the content of nano nickel was 1%.

Performance Testing

The base films prepared in Examples 1 to 7 and Comparative Examples 1 to 2 were subjected to the following performance tests, and the test results are recorded in Table 1.

1. Reflectivity

The test method refers to the spectrophotometer method with an integrating sphere in the standard GB/T 29848 "Ethylene-vinyl acetate copolymer (EVA) film for photovoltaic module encapsulation", the test instrument: UV-visible spectrophotometer, test conditions: 780 ~ 1100nm.

2. Yellowing index

The test method refers to the standard GB/T2409 "Plastic Yellowing Index Test Method"; sample size: 100x100mm; test conditions: 25℃, 50%RH.

Table 1 Performance test results of each embodiment and each comparative example

Category Infrared light reflectivity/% Yellowing Index Example 1 75% 1.55 Example 2 78% 1.46 Example 3 77% 1.27 Example 4 80% 1.65 Example 5 82% 1.38 Example 6 84% 1.05 Example 7 83% 1.26 Comparative Example 1 6% 5.31 Comparative Example 2 47% 3.79

From the analysis of the above performance test results, it can be seen that using ZIF-8 confined metal particles as the first reflective filler added to PET to prepare the first surface layer can enable the material to obtain a better infrared reflection effect of 780 to 1100 nm.

In a more preferred solution, ZIF-8 simultaneously confines two metal particles, which can further enhance the infrared light reflection ability of the base film material and prevent yellowing. Among them, ZIF-8 confines metal nickel and metal silver to enable the base film to obtain the best infrared light reflection ability and the lowest yellowing performance, and the infrared light emissivity of the polyester base film prepared by it reaches 84%.

In summary, the present application creatively adds ZIF-8 confined metal particles to PET as the first reflective filler, which can effectively improve the infrared light reflection performance of the polyester base film. Further exploration found that when ZIF-8 simultaneously confines metal nickel and metal silver materials as the first reflective filler of PET, the polyester base film obtained has the highest infrared light reflectivity and the lower the degree of yellowing.

The ultra-white polyester base film for high-reflective black backboard and the preparation method thereof of the present application are clear and easy to operate, and can obtain a polyester base film with good infrared reflection properties and anti-yellowing properties, which has practical significance.

The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments. The above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application. These changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims (10)

1. An ultra-white polyester base film for a high-reflective black backplane, characterized in that it comprises a first surface layer, an ultra-white support layer and a second surface layer, the ultra-white support layer is made of PET and PP, a second reflective filler is dispersed in the second surface layer, and the second reflective filler is nano-silicon dioxide, and a first reflective filler is dispersed in the first surface layer, and the first reflective filler is ZIF-8 confined metal particles. 2 . The ultra-white polyester base film for high-reflective black backboard according to claim 1 , wherein the content of the first reflective filler is 1% to 3%. 3 . The ultra-white polyester base film for high-reflective black backboard according to claim 2 , wherein the content of the first reflective filler is 1%. 4. The ultra-white polyester base film for high-reflective black backboard according to claim 1, characterized in that the first reflective filler is ZIF-8 internal confined metal particles, and the metal particles are any one or more combinations of platinum, nickel, palladium, and silver. 5. The ultra-white polyester base film for high-reflective black backsheet according to claim 4, characterized in that the first reflective filler is ZIF-8 internal confined metal particles, and the metal particles are nickel and silver; Or, the first reflective filler is metal particles confined inside ZIF-8, and the metal particles are platinum and silver; Or, the first reflective filler is metal particles confined inside ZIF-8, and the metal particles are platinum and nickel; Alternatively, the first reflective filler is metal particles confined inside ZIF-8, and the metal particles are palladium and silver. 6 . The ultra-white polyester base film for high-reflective black backboard according to claim 1 , wherein the particle size of the nano-silicon dioxide is 40 to 50 nm. 7. The ultra-white polyester base film for high-reflective black backboard according to claim 1, characterized in that the thickness of the first surface layer is 60-80 μm, the thickness of the ultra-white support layer is 250-350 μm, and the thickness of the second surface layer is 25-35 μm. 8. A method for preparing an ultra-white polyester base film for a high-reflective black back sheet, characterized in that it comprises the following preparation steps: S1: ZIF-8 is prepared using zinc nitrate and 2-methylimidazole, and then the ZIF-8 is added to a salt solution of metal particles and uniformly mixed to obtain a mixed solution, a reducing agent is added to the mixed solution to reduce the metal ions to metal elements, and a first reflective filler is obtained after precipitation, filtration, drying and washing, wherein the salt solution of the metal particles is any one or more combinations of platinum salt, nickel salt, palladium salt and silver salt; S2: The first reflective filler is mixed with the PET masterbatch and then injection molded to obtain a first surface layer; S3: Mixing the PET masterbatch with the PP masterbatch and then performing injection molding to obtain an ultra-white support layer; mixing the nanoporous silica with the PET masterbatch and then performing injection molding to obtain a second surface layer; S4: co-extrude the first surface layer, the ultra-white support layer and the second surface layer to obtain the ultra-white polyester base film for the high-reflective black backplane. 9. The method for preparing an ultra-white polyester base film for a high-reflective black back sheet according to claim 8, characterized in that the salt solution of the metal particles is a mixture of a nickel salt and a silver salt, wherein the molar ratio of nickel ions to silver ions is 1:1; Or, the salt solution of the metal particles is a mixture of platinum salt and silver salt, wherein the molar ratio of platinum ions to silver ions is 1:1; or, the salt solution of the metal particles is a mixture of platinum salt and nickel salt, wherein the molar ratio of platinum ions to nickel ions is 1:1; or, the salt solution of the metal particles is a mixture of palladium salt and silver salt, wherein the molar ratio of palladium ions to silver ions is 1:1. 10. A photovoltaic cell, comprising, from top to bottom, a photovoltaic backplane, a packaging material, a battery cell, a packaging material and a packaging glass, characterized in that the photovoltaic backplane comprises the ultra-white polyester base film for a high-reflective black backplane as described in any one of claims 1 to 7, or is prepared by any preparation method of claim 8 or 9, and the first surface layer is arranged on a side away from the battery cell.