CN112409938A

CN112409938A - Photovoltaic back sheet, method for preparing photovoltaic back sheet and photovoltaic module

Info

Publication number: CN112409938A
Application number: CN202011251674.0A
Authority: CN
Inventors: 白玉清; 范云峰; 邸喜强; 孟丹; 张文静; 许宁; 梁宏陆; 王小记; 李华锋; 柳青
Original assignee: Lucky Film Co Ltd
Current assignee: Lucky Film Co Ltd
Priority date: 2020-11-11
Filing date: 2020-11-11
Publication date: 2021-02-26
Anticipated expiration: 2040-11-11
Also published as: CN112409938B

Abstract

The invention provides a photovoltaic back plate, a method for preparing the photovoltaic back plate and a photovoltaic module, which comprise the following steps: the weather-resistant layer is positioned on one side, far away from the bonding layer, of the core layer, and the material forming the weather-resistant layer contains not less than 5 parts by mass of polyamide polyether block copolymer. Therefore, the manufacturing cost of the photovoltaic back plate can be reduced, and the supporting and protecting performance of the photovoltaic back plate is improved.

Description

Photovoltaic back sheet, method for preparing photovoltaic back sheet and photovoltaic module

Technical Field

The invention relates to the field of photovoltaics, in particular to a photovoltaic back sheet, a method for preparing the photovoltaic back sheet and a photovoltaic module.

Background

Solar energy is the most abundant renewable energy in the nature, is converted into electric energy through a photovoltaic module, and has unique advantages and huge development and application potentials. The photovoltaic back plate is an important component of the photovoltaic module, is assembled on the back of the cell and plays a role in protecting and supporting the cell. The performance of a photovoltaic backsheet is directly related to the operating power and service life of the photovoltaic module. At present, three main process methods are adopted for producing the photovoltaic back plate: the coating process, the composite process and the multilayer co-extrusion process, wherein the multilayer co-extrusion process is an emerging technology in recent years and has attracted wide attention. In the prior art, polyamide is usually adopted as a main coextrusion material, but the polyamide is expensive, and the electricity consumption cost of the coextrusion photovoltaic back plate taking the polyamide as the main coextrusion material is higher, so that the coextrusion photovoltaic back plate is not beneficial to practical application and popularization.

Thus, current photovoltaic backsheets, methods of making photovoltaic backsheets, and photovoltaic modules remain to be improved.

Disclosure of Invention

The present application is directed to solving, to some extent, one of the technical problems in the related art.

In one aspect of the invention, the invention provides a photovoltaic backsheet comprising: the weather-resistant layer is positioned on one side, far away from the bonding layer, of the core layer, and the material forming the weather-resistant layer contains not less than 5 parts by mass of polyamide polyether block copolymer. Therefore, the manufacturing cost of the photovoltaic back plate can be reduced, and the supporting and protecting performance of the photovoltaic back plate is improved.

According to an embodiment of the invention, the material forming the bonding layer comprises: 30-40 parts by mass of polyethylene, 30-50 parts by mass of polypropylene, 10-20 parts by mass of polyolefin elastomer, 1-20 parts by mass of first inorganic filler and 0.1-5 parts by mass of anti-aging agent. Thus, the bonding ability of the photovoltaic backsheet can be improved.

According to an embodiment of the invention, the material forming the core layer comprises: 1-10 parts by mass of the polyethylene, 60-70 parts by mass of the polypropylene, 1-10 parts by mass of the polyolefin elastomer, 1-15 parts by mass of the first inorganic filler, 1-15 parts by mass of the second inorganic filler, and 0.1-5 parts by mass of the anti-aging agent.

According to an embodiment of the present invention, the material forming the weathering layer comprises: 5-25 parts by mass of polyamide polyether block copolymer, 20-50 parts by mass of polypropylene, 10-20 parts by mass of compatilizer, 1-30 parts by mass of first inorganic filler and 0.1-10 parts by mass of anti-aging agent. Therefore, the weather resistance of the photovoltaic back sheet can be improved.

According to an embodiment of the present invention, the first inorganic filler is at least one of alumina, titanium dioxide, magnesium carbonate, aluminum sulfate, barium sulfate, aluminum silicate, silica. Therefore, the reflectivity and the mechanical strength of the photovoltaic back sheet bonding layer and the weather-resistant layer can be improved.

According to an embodiment of the invention, the second inorganic filler is at least one of talc or calcium carbonate. Therefore, the stiffness of the photovoltaic back plate core layer can be improved.

According to an embodiment of the present invention, the aging resistor includes at least one of an ultraviolet absorber and a light stabilizer. Therefore, the light aging resistance of the photovoltaic back sheet can be further improved.

According to an embodiment of the present invention, the compatibilizer is a polyolefin polar group graft copolymer having polar groups chemically bonded to a polyamide. Thereby contributing to the improvement of the compatibility of the polyamide polyether block copolymer with the polyolefin in the weathering layer.

In another aspect of the present invention, the present invention provides a method of preparing the photovoltaic backsheet as described above, comprising: forming a photovoltaic back sheet by a co-extrusion process through a first polymeric composition, a second polymeric composition and a third polymeric composition, wherein the first polymeric composition forms a bonding layer of the photovoltaic back sheet, the second polymeric composition forms a core layer of the photovoltaic back sheet, and the third polymeric composition forms a weather-resistant layer of the photovoltaic back sheet, and the third polymeric composition contains not less than 5 parts by mass of a polyamide polyether block copolymer. The photovoltaic backsheet has all the features and advantages of the photovoltaic backsheet described above, and are not described herein again.

According to the embodiment of the invention, the temperature of the co-extrusion process is 160-260 ℃, and the rotating speed of the extrusion rod of the co-extrusion process is 200-300 r/min. Thereby, formation of a photovoltaic backsheet of suitable thickness is facilitated.

In yet another aspect of the present invention, the present invention provides a photovoltaic module comprising: the photovoltaic front plate comprises a photovoltaic front plate, a first hot-melt adhesive film layer, wherein the first hot-melt adhesive film layer is located on one side of the photovoltaic front plate, a cell piece is located on one side of the first hot-melt adhesive film layer away from the photovoltaic front plate, a second hot-melt adhesive film layer is located on one side of the second hot-melt adhesive film layer away from the cell piece, and a photovoltaic back plate is located on one side of the second hot-melt adhesive film layer away from the cell piece and is prepared by the method. Therefore, the photovoltaic module has all the characteristics and advantages of the photovoltaic back plate and the method for preparing the photovoltaic back plate, and the description is omitted.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 shows a schematic structural view of a photovoltaic backsheet according to one embodiment of the present invention.

Description of reference numerals: 1000: a photovoltaic backsheet; 100: a bonding layer; 200: a core layer; 300: and a weather-resistant layer.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

The present application is made based on the findings of the inventors on the following problems:

the weather-resistant layer taking polyamide as a main material has better weather resistance, and the material for forming the photovoltaic back plate in the prior art is mainly polyamide, but the cost of the polyamide material is higher, so that the weather-resistant layer is not beneficial to large-scale popularization and application of the photovoltaic back plate. The inventor finds that the photovoltaic back plate taking polyolefin as the main material has the characteristics of low cost and good weather resistance. The weather resistance of the weather-resistant layer can be further improved by adding the polyamide polyether block copolymer into the weather-resistant layer, the compatibility of the polyamide polyether block copolymer and polyolefin can be effectively improved by adding the compatilizer into the weather-resistant layer, and the effective adhesion of the weather-resistant layer and the core layer can be realized without additionally adding an adhesive film layer in a co-extrusion process.

In one aspect of the present invention, referring to fig. 1, the present invention provides a photovoltaic backsheet 1000 comprising: the weather-resistant layer 300 comprises a bonding layer 100 and a core layer 200, wherein the core layer 200 is positioned on one side of the bonding layer, and the weather-resistant layer 300 is positioned on one side of the core layer 200 far away from the bonding layer 100, and the material for forming the weather-resistant layer 300 contains not less than 5 parts by mass of polyamide polyether block copolymer. The photovoltaic backboard is connected with the cell through the bonding of the bonding layer of the photovoltaic backboard and the hot melt adhesive film layer, the mechanical property of the photovoltaic backboard is improved through the core layer of the photovoltaic backboard, and the weather resistance of the photovoltaic backboard is improved through the weather-resistant layer of the photovoltaic backboard. Therefore, the weather resistance of the photovoltaic backboard can be improved by utilizing the good weather resistance of the polyamide polyether block copolymer material, the manufacturing cost of the photovoltaic backboard is obviously reduced, and the photovoltaic backboard is further promoted and applied. Therefore, the weather-resistant layer adopts the polyamide polyether block copolymer containing not less than 5 parts by mass, so that the condition that a large amount of expensive polyamide is used in the weather-resistant layer can be avoided, and the obtained photovoltaic back plate can still have the mechanical property capable of meeting the requirements of photovoltaic modules.

According to some embodiments of the present invention, polyethylene may be included in both the materials forming the tie layer and the core layer. The polyethylene material can effectively improve the low temperature resistance and the electric insulation performance of the polypropylene material, and can improve the bonding performance between the material and the adjacent membrane layer. The type of polyethylene in the materials forming the tie layer and the core layer is not particularly limited, for example, the polyethylene in the materials forming the tie layer and the core layer may be one or more of high density polyethylene, low density polyethylene, linear low density polyethylene.

According to some embodiments of the present invention, the mass part of the polyethylene in the material forming the tie layer is not particularly limited, and for example, the mass part of the polyethylene in the material forming the tie layer may range from 30 to 40 mass parts. When the mass part of polyethylene in the material for forming the bonding layer is less than 30 parts, the bonding force between the bonding layer of the photovoltaic back plate and the second hot melt adhesive film layer is small, and the photovoltaic back plate is easy to fall off in the using process. When the polyethylene in the material forming the adhesive layer is more than 40 parts by mass, the adhesive layer has poor heat resistance and is likely to be crushed during lamination treatment, and excessive polyethylene causes poor adhesion between the adhesive layer and the core layer and weak adhesion.

According to some embodiments of the present invention, the mass part of the polyethylene in the material forming the core layer is not particularly limited, and for example, the mass part of the polyethylene in the material forming the core layer may range from 1 to 10 mass parts. When the mass part of the polyethylene in the material for forming the core layer is less than 1 mass part, the toughness of the core layer is poor, the low-temperature resistance is poor, and the use requirement of the photovoltaic back plate cannot be met. When the mass part of the polyethylene in the material forming the core layer is greater than 10 mass parts, the rigidity and stiffness of the core layer are both too high, which is not favorable for the practical application of the photovoltaic back sheet.

According to some embodiments of the present invention, polypropylene may be included in the materials forming the tie layer, the core layer, and the weatherable layer, because polyethylene has a low melting point, is easily crushed during lamination, and is not beneficial to maintaining the effective insulation thickness (DTI) of the backsheet, and thus the main material of the materials forming the tie layer, the core layer, and the weatherable layer should still be polypropylene. The kind of polypropylene in the materials forming the tie layer and the core layer is not particularly limited, and in particular, the polypropylene in the materials forming the tie layer and the core layer may be one or more of isotactic polypropylene, block polypropylene, and atactic polypropylene.

According to some embodiments of the present invention, the mass part of the polypropylene in the material forming the adhesive layer is not particularly limited, and for example, the mass part of the polypropylene in the material forming the adhesive layer may range from 30 to 50 mass parts. When the polypropylene is contained in an amount of less than 30 parts by mass in the material forming the adhesive layer, the adhesive layer has a low melting point and is likely to be crushed during lamination. When the mass part of the polypropylene in the material for forming the bonding layer is more than 50 parts, the bonding force between the bonding layer of the photovoltaic back plate and the second hot melt adhesive film layer is small, and the photovoltaic back plate is easy to fall off in the using process.

According to some embodiments of the present invention, the polypropylene is a rigid material, the core layer of the photovoltaic backsheet mainly plays a role of supporting and reinforcing, the mass part of the polypropylene in the core layer mainly affects the strength and stiffness of the photovoltaic backsheet, the mass part of the polypropylene in the material forming the core layer is not particularly limited, for example, the mass part of the polypropylene in the material forming the core layer may range from 60 to 70 mass parts. When the mass part of the polypropylene in the material for forming the core layer is less than 60 mass parts, the photovoltaic back plate has poor strength and cannot play a supporting role. When the mass part of the polypropylene in the material for forming the core layer is more than 70 parts, the low-temperature resistance of the photovoltaic back plate is poor, and the use requirement of the photovoltaic back plate cannot be met.

According to some embodiments of the present invention, a certain mass portion of polypropylene should be added to the material forming the weather-resistant layer to improve the adhesion between the weather-resistant layer and the core layer, so as to facilitate the formation of the co-extruded layer. The mass part of the polypropylene in the material forming the weather-resistant layer is not particularly limited, and for example, the mass part of the polypropylene in the material forming the weather-resistant layer may range from 20 to 50 mass parts. When the mass part of polypropylene in the material forming the weather-resistant layer is less than 20 mass parts, the adhesion force between the weather-resistant layer and the core layer is small, which is not favorable for forming the co-extrusion layer. When the mass part of the polypropylene in the material forming the weather-resistant layer is more than 50 mass parts, the content of other functional fillers, such as polyamide-polyether block copolymer, compatibilizer, etc., in the material forming the weather-resistant layer is correspondingly reduced, which will significantly reduce the weather resistance of the weather-resistant layer.

According to some embodiments of the present invention, the materials forming the tie layer, the core layer, and the weather-resistant layer may each include a first inorganic filler for improving reflectivity and mechanical strength, the kind of the first inorganic filler is not particularly limited, and in particular, the first inorganic filler in the materials forming the tie layer, the core layer, and the weather-resistant layer may be at least one of alumina, titanium dioxide, magnesium carbonate, aluminum sulfate, barium sulfate, aluminum silicate, and silica.

According to some embodiments of the present invention, the mass part of the first inorganic filler in the material forming the adhesive layer is not particularly limited. For example, the mass part of the first inorganic filler in the material forming the adhesive layer may range from 1 to 20 mass parts. When the mass part of the first inorganic filler in the material forming the adhesive layer is less than 1 mass part, the first inorganic filler is less dispersed in the adhesive layer, and a high reflection effect is not achieved. When the mass part of the first inorganic filler in the material forming the adhesive layer is greater than 20 mass parts, the reflectance of the adhesive layer can be improved within a certain addition amount range due to the first inorganic filler, and the mechanical strength of the adhesive layer can be reduced when the content of the first inorganic filler is too high, while the manufacturing cost is increased.

According to some embodiments of the present invention, the mass part of the first inorganic filler in the material forming the core layer is not particularly limited, and in particular, the mass part of the first inorganic filler in the material forming the core layer may range from 1 to 15 mass parts. When the mass part of the first inorganic filler in the material forming the core layer is less than 1 mass part, the first inorganic filler is less dispersed in the core layer, and a higher reflection effect cannot be achieved; when the mass part of the first inorganic filler in the material forming the core layer is greater than 15 mass parts, the reflectance of the core layer can be improved within a certain addition amount range due to the first inorganic filler, the mechanical strength of the core layer can be reduced when the content of the first inorganic filler is too high, and the manufacturing cost is increased.

According to some embodiments of the present invention, the mass part of the first inorganic filler in the material forming the weathering layer is not particularly limited, and in particular, the mass part of the first inorganic filler in the material forming the weathering layer may range from 1 to 30 mass parts. When the mass part of the first inorganic filler in the material forming the weathering layer is less than 1 mass part, the first inorganic filler is less dispersed in the weathering layer and does not achieve a high reflection effect; when the mass part of the first inorganic filler in the material forming the weathering layer is greater than 30 mass parts, since the first inorganic filler can increase the reflectance of the weathering layer within a certain addition amount range, the mechanical strength of the weathering layer is reduced when the content of the first inorganic filler is too high, and the manufacturing cost is increased.

According to some embodiments of the present invention, a second inorganic filler may be further included in the material forming the core layer, and the kind of the second inorganic filler is not particularly limited, for example, the second inorganic filler in the material forming the core layer may be at least one of talc or calcium carbonate. According to some embodiments of the invention, the second inorganic filler in the material forming the core layer is used to improve the support properties of the core layer. The mass part of the second inorganic filler in the material forming the core layer is not particularly limited, and for example, the mass part of the second inorganic filler in the material forming the core layer may range from 1 to 15 mass parts. When the mass part of the second inorganic filler in the material forming the core layer is less than 1 mass part, the dispersion of the second inorganic filler in the core layer is small, the rigidity of the core layer is insufficient, and the requirement of the support performance cannot be satisfied. When the mass part of the second inorganic filler in the material for forming the core layer is larger than 15 mass parts, the content of the second inorganic filler in the core layer is too much, the rigidity of the material for the core layer is too high, and the core layer can be broken after the photovoltaic backboard is bent at a certain radian in practical application, so that the use requirement cannot be met.

According to some embodiments of the present invention, an aging resistor may be included in each of materials forming the tie layer, the core layer, and the weathering layer, the kind of the aging resistor is not particularly limited, and in particular, the aging resistor may be at least one of an ultraviolet absorber and a light stabilizer. The ultraviolet absorbent can absorb the ultraviolet part in sunlight and a fluorescent light source, and the ultraviolet absorbent does not change, so that the light aging influence of ultraviolet on the photovoltaic backboard is reduced. When the anti-aging agent contains the ultraviolet absorbent and the light stabilizer, the ultraviolet absorbent effect which cannot be achieved by a single ultraviolet absorbent can be achieved. Namely, when the anti-aging agent contains the ultraviolet absorber and the light stabilizer, the ultraviolet absorption effect of the photovoltaic back plate can be effectively improved, the photodegradation is inhibited or weakened, the yellowing and the loss of the retardation physical property of the photovoltaic back plate are effectively prevented, and the light aging resistance is improved. Specifically, the ultraviolet absorbent can be 2-hydroxy-4-n-octoxybenzophenone, and the light stabilizer can be bis (2,2,6, 6-tetramethyl-4-piperidyl) sebacate.

According to some embodiments of the present invention, the kind of the aging resistor is not particularly limited, for example, the aging resistor may further include an acid absorbent, an antioxidant, and a radical quencher. According to an embodiment of the present invention, the kind of the acid absorbent is not particularly limited, and for example, the acid absorbent may be calcium stearate. According to some embodiments of the present invention, the kind of the antioxidant is not particularly limited, and for example, the antioxidant may be one or more of a hindered phenol type antioxidant, a phosphite type antioxidant and a thioester type antioxidant, and specifically, the antioxidant may be pentaerythritol [ β - (3 ', 5 ' -di-t-butyl-4 ' -hydroxyphenyl) propionate ] and tris (2, 4-di-t-butylphenyl) phosphite. According to an embodiment of the present invention, the kind of the radical quencher is not particularly limited, and for example, the radical quencher may be a hindered amine-type radical quencher.

According to some embodiments of the present invention, the anti-aging agent may delay aging of the photovoltaic backsheet, thereby extending the service life of the photovoltaic backsheet. The mass part of the antioxidant in the materials forming the tie layer and the core layer is not particularly limited, and specifically, the mass part of the antioxidant in the materials forming the tie layer and the core layer may range from 0.1 to 5 parts by mass. When the anti-aging agent in the materials forming the bonding layer and the core layer is less than 0.1 part by mass, the obtained photovoltaic back plate cannot meet the anti-aging requirement of daily use; when the anti-aging agent in the materials forming the bonding layer and the core layer is more than 5 parts by mass, the anti-aging performance of the bonding layer and the core layer can be improved in a certain addition proportion, when the anti-aging agent in the bonding layer and the core layer exceeds a certain proportion, the anti-aging effect of the anti-aging agent cannot be increased along with the increase of the content of the anti-aging agent, and the elasticity of the materials can be influenced by excessive anti-aging agent.

According to some embodiments of the present invention, the weather-resistant layer is located on the outermost layer of the photovoltaic back sheet, and is in direct contact with the external environment, so that the weather resistance of the weather-resistant layer is the highest requirement. The mass part of the antioxidant in the material forming the weather-resistant layer should be greater than the mass part of the antioxidant in the materials forming the tie layer and the core layer. The mass part of the antioxidant in the material forming the weathering layer is not particularly limited, and specifically, the mass part of the antioxidant in the material forming the weathering layer may range from 0.1 to 10 mass parts. When the mass part of the antioxidant in the material forming the weather-resistant layer is less than 1 mass part, the content of the antioxidant in the weather-resistant layer is too small, and the weather resistance of the weather-resistant layer cannot meet the use requirements. When the mass part of the anti-aging agent in the material for forming the weather-resistant layer is more than 10 mass parts, the anti-aging agent with high concentration can be separated out to the surface of the photovoltaic back plate due to small molecular weight of the anti-aging agent, so that the attractiveness and the use of the photovoltaic back plate are affected, the price of the anti-aging agent is high, and the manufacturing cost of the photovoltaic back plate can be obviously increased due to the excessive mass part of the anti-aging agent in the weather-resistant layer.

According to some embodiments of the present invention, the materials forming both the tie layer and the core layer may include an alpha olefin copolymer therein. The alpha olefin copolymer is an elastomer material, has the advantages of low softening point and good compatibility with polypropylene materials, has chain segment entanglement at the melt interface of the hot melt adhesive film layer in the lamination process, increases intermolecular acting force, and improves the bonding property with the hot melt adhesive film layer. The polyolefin elastomer in the materials forming the adhesive layer and the core layer is not particularly limited, and for example, the polyolefin elastomer in the materials forming the adhesive layer and the core layer may be one of an ethylene-alpha olefin copolymer, a propylene-alpha olefin copolymer, or a mixture of both.

According to some embodiments of the present invention, the polyolefin elastomer mainly serves as a compatibilizer for polyethylene and polypropylene, improving compatibility of the polyethylene and the polypropylene, and further increasing toughness of the adhesive layer and adhesion between the adhesive layer and the second hot melt adhesive film layer. The mass part of the polyolefin elastomer in the material forming the adhesive layer is not particularly limited, and for example, the mass part of the polyolefin elastomer in the material forming the adhesive layer may range from 10 to 20 mass parts. When the mass part of the polyolefin elastomer in the material forming the adhesive layer is less than 1 mass part, the compatibility of the polyethylene and the polypropylene in the adhesive layer is poor, which is not favorable for forming a layered structure. When the polyolefin elastomer in the material forming the adhesive layer is more than 20 parts by mass, the melting point of the material forming the adhesive layer is too low to satisfy the daily use requirements.

According to some embodiments of the present invention, the part by mass of the polyolefin elastomer in the material forming the core layer is not particularly limited, and for example, the part by mass of the polyolefin elastomer in the material forming the core layer may range from 1 to 10 parts by mass. When the mass part of the polyolefin elastomer in the material forming the core layer is less than 1 mass part, the compatibility of polyethylene and polypropylene in the core layer is poor, which is not favorable for forming a layered structure. When the polyolefin elastomer in the material forming the core layer is more than 10 parts by mass, the melting point of the material forming the core layer is too low to meet the daily use requirements.

According to some embodiments of the invention, a certain mass part of polypropylene should be added to the material forming the weather-resistant layer to improve the adhesion between the weather-resistant layer and the core layer, so as to facilitate the formation of the co-extrusion layer, but the weather resistance of the polypropylene material is poor, and the single polypropylene cannot meet the weather resistance requirement of the weather-resistant layer. The polyamide polyether block copolymer has good compatibility with polypropylene, has excellent weather resistance and low price, so that a layered structure with good weather resistance is favorably formed and the manufacturing cost of the photovoltaic back plate is favorably reduced by adding the polyamide polyether block copolymer into the weather-resistant layer. The material forming the weathering layer may include a polyamide polyether copolymer. The polyamide polyether block copolymer is used in the material for forming the weather-resistant layer, and the formed weather-resistant layer has good weather resistance and good compatibility with polypropylene. The weather-resistant layer and the core layer can be effectively bonded without using a bonding agent between the two layers in the coextrusion process, and the weather-resistant layer and the core layer can not be delaminated and fall off in the use process. According to some embodiments of the present invention, the part by mass of the polyamide-polyether block copolymer in the material forming the weathering layer is not particularly limited, for example the part by mass of the polyamide-polyether block copolymer in the material forming the weathering layer may range from 5 to 25 parts by mass. When the mass part of the polyamide-polyether block copolymer in the material forming the weathering layer is less than 5 mass parts, the polyamide-polyether block copolymer is less dispersed in the weathering layer and the weathering layer is inferior in weathering performance. When the mass part of the polyamide-polyether block copolymer in the material forming the weather-resistant layer is more than 25 mass parts, the content of the polyamide-polyether block copolymer in the weather-resistant layer is large, which is disadvantageous in forming a good bond between the weather-resistant layer and the core layer.

According to some embodiments of the present invention, a compatibilizer may be included in the material forming the weathering layer, and the compatibilizer in the material forming the weathering layer may improve the compatibility of the polyamide polyether block copolymer and the polyolefin in the weathering layer. The kind of the compatibilizing agent in the material forming the weather-resistant layer is not particularly limited, and for example, the compatibilizing agent may be a polyolefin polar group graft copolymer. Specifically, the polyolefin body of the polyolefin polar group graft copolymer may be at least one of polypropylene, ethylene- α -olefin copolymer, and propylene- α -olefin copolymer. According to some embodiments of the present invention, the polar group of the polyolefin polar group graft copolymer is not particularly limited as long as the polar group is chemically bonded to the polyamide. Specifically, the polar group of the polyolefin polar group graft copolymer may be at least one of an acid anhydride, an acid, an epoxide, a silane, and an isocyanate. According to some embodiments of the present invention, the mass part of the compatibilizer in the material forming the weathering layer is not particularly limited, for example, the mass part of the compatibilizer in the material forming the weathering layer may range from 10 to 20 mass parts. When the mass part of the compatilizer in the material for forming the weather-resistant layer is less than 10 mass parts, the content of the compatilizer is too low, the compatibility of the polyamide polyether block copolymer and the polyolefin in the weather-resistant layer cannot be effectively improved, and the layered structure of the weather-resistant layer is not favorably formed. When the mass part of the compatibilizer in the material forming the weather-resistant layer is more than 20 mass parts, the rigidity of the weather-resistant layer is too high, which is not favorable for the practical application of the photovoltaic back sheet.

In another aspect of the invention, the invention provides a method of making the photovoltaic backsheet described above, comprising: and (2) forming the photovoltaic back sheet by a co-extrusion process through a first polymerization composition, a second polymerization composition and a third polymerization composition, wherein the first polymerization composition forms a bonding layer of the photovoltaic back sheet, the second polymerization composition forms a core layer of the photovoltaic back sheet, and the third polymerization composition forms a weather-resistant layer of the photovoltaic back sheet, and the mass part of the polyamide-polyether block copolymer in the third polymerization composition is not less than 5 parts. Compared with the traditional backboard production process, such as a coating process and a composite process, the co-extrusion process has the advantages that: the co-extrusion process is to extrude the polymerization composition in a plurality of extruders at the same time, and the polymer composition is formed at one time without double-sided processing, thereby saving the working hours and the labor cost; in the production process of the coating process backboard, the composite adhesive and the coating layer are dissolved by the solvent, the solvent is volatilized in the production process to influence the environment, and the co-extrusion process is free of the solvent and is more environment-friendly; in the multilayer coextrusion, the thickness of each layer and the raw material formula can be flexibly adjusted according to the requirement, and the photovoltaic back plate with moderate thickness and adjustable components can be obtained. The photovoltaic backsheet has all the features and advantages of the previous photovoltaic backsheet, which are not described in detail herein.

According to some embodiments of the present invention, the temperature of the co-extrusion process is not particularly limited, and in particular, the temperature range of the co-extrusion process may be 160-260 degrees celsius. When the temperature of the co-extrusion process is less than 160 ℃, the materials forming the photovoltaic backsheet cannot be sufficiently melt blended, and a co-extruded film layer cannot be formed. When the temperature of the co-extrusion process is higher than 260 ℃, the melt flowability of the material for forming the photovoltaic back panel is too high, so that the co-extrusion film layer is not easy to form or the obtained co-extrusion film layer is not interpenetrated between layers, and the use requirement of the photovoltaic back panel cannot be met.

According to some embodiments of the present invention, the extrusion rod rotation speed of the co-extrusion process is not particularly limited, and in particular, the extrusion rod rotation speed of the co-extrusion process may range from 200-. When the rotating speed of an extrusion rod in the co-extrusion process is less than 200r/min, the rotating speed of the extrusion rod is too low, and the formed photovoltaic backboard is thin and cannot meet the requirement on weather resistance of the photovoltaic backboard in the using process. When the rotating speed of an extrusion rod of the co-extrusion process is more than 300r/min, the thickness of the formed photovoltaic back plate is thick, and raw materials are wasted.

In yet another aspect of the present invention, the present invention provides a photovoltaic module comprising: the photovoltaic front plate comprises a photovoltaic front plate body, a first hot melt adhesive film layer, a battery piece, a second hot melt adhesive film layer and a photovoltaic back plate, wherein the first hot melt adhesive film layer is located on one side of the photovoltaic front plate body, the battery piece is located on one side, away from the photovoltaic front plate, of the first hot melt adhesive film layer, the second hot melt adhesive film layer is located on one side, away from the first hot melt adhesive film layer, of the battery piece, and the photovoltaic back plate is located on one side, away from the battery piece, of the second hot melt adhesive film layer, and is prepared by the method or. Therefore, the photovoltaic module has all the characteristics and advantages of the photovoltaic back plate and the method for preparing the photovoltaic back plate, and the description is omitted.

The following embodiments are provided to illustrate the present application, and should not be construed as limiting the scope of the present application. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

The first, second and third polymeric compositions were melt extruded in an extruder to form three layer coextruded backsheets according to the formulations in the examples and comparative tables, respectively. The unit of each component in the table is part by mass.

Example 1:	first polymeric composition	Second polymeric composition	Third polymeric composition
				Polyamide polyether block copolymers	/	/	5
Compatilizer	/	/	10
				Polypropylene	50	68	50
Polyethylene	30	10	/
				Polyolefin elastomer	10	1	/
First inorganic filler	6	1	30
				Second inorganic filler	/	15	/
Anti-aging agent	4	5	5

Example 2:	first polymeric composition	Second polymeric composition	Third polymeric composition
				Polyamide polyether block copolymers	/	/	25
Compatilizer	/	/	15
				Polypropylene	30	68.9	49
Polyethylene	40	1	/
				Polyolefin elastomer	20	10	/
First noneMachine packing	8	10	1
				Second inorganic filler	/	10	/
Anti-aging agent	2	0.1	10

Example 3:	first polymeric composition	Second polymeric composition	Third polymeric composition
				Polyamide polyether block copolymers	/	/	14.9
Compatilizer	/	/	20
				Polypropylene	40	70	40
Polyethylene	39	9	/
				Polyolefin elastomer	15	6	/
First inorganic filler	1	15	25
				Second inorganic filler	/	1	/
Anti-aging agent	5	4	0.1

Example 4:	first polymeric composition	Second polymeric composition	Third polymeric composition
				Polyamide polyether block copolymers	/	/	15
Compatilizer	/	/	10
				Polypropylene	50	70	50
Polyethylene	30	1	/
				Polyolefin elastomer	10	10	/
First inorganic filler	5	5	15
				Second inorganic filler	/	10	/
Anti-aging agent	5	4	10

Example 5:	first polymeric composition	Second polymeric composition	Third polymeric composition
				Polyamide polyether block copolymers	/	/	14.9
Compatilizer	/	/	20
				Polypropylene	30	60	40
Polyethylene	40	10	/
				Polyolefin elastomer	20	10	/
First inorganic filler	6	5	15
				Second inorganic filler	/	5	/
Anti-aging agent	4	10	0.1

Example 6:	first polymeric composition	Second polymerizationComposition comprising a metal oxide and a metal oxide	Third polymeric composition
				Polyamide polyether block copolymers	/	/	15
Compatilizer	/	/	15
				Polypropylene	40	65	35
Polyethylene	35	5	/
				Polyolefin elastomer	15	5	/
First inorganic filler	6	10	25
				Second inorganic filler	/	11	/
Anti-aging agent	4	4	10

Comparative example 1:	first polymeric composition	Second polymeric composition	Third polymeric composition
				Polypropylene	35	64	/
Polyethylene	30	10	/
				Polyolefin elastomer	20	10	/
Polyamide	/	/	80
				First inorganic filler	10	10	12
Second inorganic filler	/	10	/
				Anti-aging agent	5	6	8

Comparative example 2:	first polymeric composition	Second polymeric composition	Third polymeric composition
				Polypropylene	35	64	60
Polyethylene	30	10	10
				Polyolefin elastomer	20	10	10
Polyamide	/	/	/
				First inorganic filler	10	10	12
Second inorganic filler	/	10	/
				Anti-aging agent	5	6	8

Comparative example 3:	first of allPolymeric compositions	Second polymeric composition	Third polymeric composition
				Polypropylene	35	64	35
Polyethylene	30	10	5
				Polyolefin elastomer	20	10	5
Polyamide	/	/	35
				First inorganic filler	10	10	12
Second inorganic filler	/	10	/
				Anti-aging agent	5	6	8

Comparative example 4:	first polymeric composition	Second polymeric composition	Third polymeric composition
				Polyamide polyether block copolymers	/	/	10
Compatilizer	/	/	10
				Polypropylene	55	75	55
Polyethylene	20	/	/
				Polyolefin elastomer	5	6	/
First inorganic filler	15	5	20
				Second inorganic filler	/	10	/
Anti-aging agent	5	4	5

Comparative example 5:	first polymeric composition	Second polymeric composition	Third polymeric composition
				Polyamide polyether block copolymers	/	/	25
Compatilizer	/	/	/
				Polypropylene	30	50	40
Polyethylene	50	20	/
				Polyolefin elastomer	5	6	/
First inorganic filler	10	9	25
				Second inorganic filler	/	11	/
Anti-aging agent	5	4	10

The performance test results are shown in the following table:

table 1:

table 2:

as can be seen from table 1, the weather-resistant layer of the photovoltaic back sheet is added with polyamide, so that the weather resistance is improved, but the compatibility between polyamide and polypropylene is poor, and blending modification cannot be performed, and the weather-resistant layer and the core layer cannot be bonded without using a binder. The problems can be effectively solved by adding the polyamide polyether copolymer into the weather-resistant layer, and the obtained photovoltaic back plate has the advantages of good weather resistance, tight interlayer adhesion and good appearance uniformity.

As can be seen from table 2, if the mass part of the polyethylene in the bonding layer of the photovoltaic back sheet is greater than 40 parts, the bonding layer is easily crushed during lamination, and if the mass part of the polyethylene in the bonding layer of the photovoltaic back sheet is less than 30 parts, the bonding force between the photovoltaic back sheet and the second hot melt adhesive film layer is low. The polyethylene in the core layer plays a toughening role, if the mass part of the polyethylene in the core layer is less than 1 part, the elongation at break of the photovoltaic back plate is reduced, and the influence is greater under the low-temperature condition; if the mass part of the polyethylene in the core layer is more than 10 parts, it will result in a decrease in the tensile strength of the backsheet. The compatibility of the polyamide polyether copolymer with the polypropylene in the weathering layer can be effectively improved by the addition of a compatibilizer in the weathering layer.

In the description of the present invention, the terms "upper", "lower", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of describing the present invention but do not require that the present invention must be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description herein, references to the description of "one embodiment," "another embodiment," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A photovoltaic backsheet, comprising:

an adhesive layer, a bonding layer,

a core layer on one side of the tie layer,

a weather-resistant layer positioned on a side of the core layer away from the bonding layer,

the material for forming the weather-resistant layer contains not less than 5 parts by mass of polyamide-polyether block copolymer.

2. The photovoltaic backsheet according to claim 1, wherein the material forming the tie layer comprises: 30-40 parts by mass of polyethylene, 30-50 parts by mass of polypropylene, 10-20 parts by mass of polyolefin elastomer, 1-20 parts by mass of first inorganic filler and 0.1-5 parts by mass of anti-aging agent.

3. The photovoltaic backsheet according to claim 1, wherein the material forming the core layer comprises: 1-10 parts by mass of the polyethylene, 60-70 parts by mass of the polypropylene, 1-10 parts by mass of the polyolefin elastomer, 1-15 parts by mass of the first inorganic filler, 1-15 parts by mass of the second inorganic filler, and 0.1-5 parts by mass of the anti-aging agent.

4. The photovoltaic backsheet according to claim 1, wherein the material forming the weatherable layer comprises: 5-25 parts by mass of polyamide polyether block copolymer, 20-50 parts by mass of polypropylene, 10-20 parts by mass of compatilizer, 1-30 parts by mass of first inorganic filler and 0.1-10 parts by mass of anti-aging agent.

5. The photovoltaic backsheet according to any one of claims 2 to 4, wherein the first inorganic filler is at least one of alumina, titanium dioxide, magnesium carbonate, aluminum sulfate, barium sulfate, aluminum silicate, silicon dioxide;

optionally, the second inorganic filler is at least one of talc or calcium carbonate.

6. The photovoltaic backsheet according to any one of claims 2-4, wherein the aging resistors comprise at least one of UV absorbers and light stabilizers.

7. The photovoltaic backsheet according to claim 4, wherein the compatibilizer is a polyolefin polar group graft copolymer having polar groups chemically bonded to a polyamide.

8. A method of making the photovoltaic backsheet of any one of claims 1-7 comprising:

forming the first, second, and third polymeric compositions into a photovoltaic backsheet via a coextrusion process,

the first polymeric composition forms a tie layer of the photovoltaic backsheet, the second polymeric composition forms a core layer of the photovoltaic backsheet, the third polymeric composition forms a weatherable layer of the photovoltaic backsheet,

wherein the third polymeric composition comprises not less than 5 parts by mass of a polyamide polyether block copolymer.

9. The method as claimed in claim 8, wherein the temperature of the co-extrusion process is 160-260 ℃, and the rotation speed of the extrusion rod of the co-extrusion process is 200-300 r/min.

10. A photovoltaic module, comprising:

a photovoltaic front-plate,

a first hot melt adhesive film layer positioned on one side of the photovoltaic front plate,

the cell piece is positioned on one side of the first hot melt adhesive film layer far away from the photovoltaic front plate,

a second hot melt adhesive film layer, wherein the second hot melt adhesive film layer is positioned on one side of the battery piece far away from the first hot melt adhesive film layer,

a photovoltaic backsheet on the side of the second hot melt adhesive film layer remote from the cell sheet, the photovoltaic backsheet being as claimed in any one of claims 1 to 7 or prepared by the process of claim 8 or 9.