Packaging adhesive film, preparation method thereof and photovoltaic module

Abstract

The invention provides a packaging adhesive film, a preparation method thereof and a photovoltaic module, and particularly relates to the technical field of photovoltaic module packaging. The packaging adhesive film comprises a central area and an edge area which are mutually bordered along the width direction; and the edge area is made of a water vapor barrier material. The packaging adhesive film provided by the invention is divided into the central area and the edge area which are mutually bordered in the width direction, and the edge area is made of the water vapor barrier material, so that the water vapor barrier performance of the packaging adhesive film is enhanced, permeation of water vapor from the edge of the module is effectively reduced, and more comprehensive protection is provided for a battery piece in the photovoltaic module. Meanwhile, the water vapor barrier material can limit permeation of water molecules, so that hydrolysis reaction and ion migration are reduced, the PID effect is reduced, and the performance of the battery piece is protected.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic module packaging, and in particular to a packaging adhesive film and a preparation method thereof, and a photovoltaic module. Background Art

[0002] In the development of photovoltaic modules, N-type cells have gradually replaced PERC cells due to their higher power generation efficiency and become the mainstream of the market. However, N-type cells are more sensitive to water vapor, which makes the selection of packaging materials for photovoltaic modules particularly important. In order to improve the reliability of modules, most photovoltaic module manufacturers choose to produce double-glass modules because double-glass modules have better water resistance than single-glass modules.

[0003] Despite the use of double-glass modules, the EVA film will still hydrolyze under high temperature conditions to produce acetic acid, which will corrode the cells. Over time, the EVA film will turn seriously yellow, affecting the photovoltaic conversion efficiency of the module. In addition, the EVA film also has PID (potential induced degradation), which will further reduce the performance of the module.

[0004] In order to solve these problems, polyolefin elastomer (POE) film came into being. POE film does not contain unsaturated bonds, has a stable structure, and has better heat resistance than EVA film. It will not hydrolyze to produce acetic acid, thus avoiding corrosion to the battery cells. More importantly, POE film does not have PID phenomenon and has lower leakage current performance. These advantages make EPE / POE film containing POE components more popular in the market.

[0005] Although POE film has many advantages, it is a non-polar material with low crystallinity and a high proportion of amorphous phase, which still causes a small amount of water vapor to penetrate the edge of the double-glass module. This is especially critical for HJT and perovskite cells, which are extremely sensitive to water vapor, because the penetration of water vapor will affect the long-term reliability of the module. At present, in order to solve the problem of edge water vapor penetration, there is a method of using butyl adhesive products to separately encapsulate the edge of the module, but this method has a general water vapor barrier effect, high cost, and adds new process steps, which has certain limitations.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] One of the objectives of the present invention is to provide a packaging adhesive film, aiming to solve at least one of the above-mentioned technical problems in the prior art.

[0008] A second object of the present invention is to provide a method for preparing a packaging film.

[0009] A third object of the present invention is to provide a photovoltaic module.

[0010] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted: A first aspect of the present invention provides a packaging adhesive film, comprising a central area and an edge area bordering each other along a width direction; The material of the edge area is a water vapor barrier material.

[0011] Furthermore, the water vapor barrier material includes polyolefin, modified polyolefin, fluorine-containing polymer or chlorine-containing polymer.

[0012] The polyolefin includes polyethylene, polypropylene or polybutylene.

[0013] The modified polyolefin includes silane-modified polyolefin or acid anhydride-modified polyolefin.

[0014] The polyethylene includes linear low-density polyethylene, linear medium-density polyethylene or linear high-density polyethylene.

[0015] The fluorine-containing polymer includes polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer.

[0016] The chlorine-containing polymer includes polyvinylidene chloride.

[0017] Furthermore, the material of the central area includes EVA, EPE or POE.

[0018] Furthermore, the edge region includes a first edge region and a second edge region.

[0019] The first edge region and the second edge region do not border each other.

[0020] Furthermore, the packaging film includes a first edge region, a center region and a second edge region which are sequentially arranged along the width direction.

[0021] The width of the first edge region and / or the second edge region is 0.05-10 mm, preferably 0.1-5 mm.

[0022] The second aspect of the present invention provides a method for preparing the encapsulating adhesive film, wherein the central area and the edge area are integrated by hot pressing to obtain the encapsulating adhesive film.

[0023] or, The central area and the edge area are co-extruded to obtain a packaging film.

[0024] Further, the heat pressing is performed by a heat laminator.

[0025] The temperature of the hot pressing is 140-160° C., and the pressure is -100--10 KPa.

[0026] Further, the multi-zone co-extrusion process is: The raw materials of the central area and the raw materials of the edge area are respectively added into different feeding chambers of the screw extruder, and then co-extruded through the T-shaped die mouth, and the materials of different areas are melted together to obtain the packaging film.

[0027] A third aspect of the present invention provides a photovoltaic module, comprising the above-mentioned packaging film.

[0028] Furthermore, the packaging film includes a first packaging film and a second packaging film.

[0029] The first packaging film and the second packaging film are arranged vertically.

[0030] Compared with the prior art, the present invention has at least the following beneficial effects: The encapsulation film provided by the present invention is divided into a central area and an edge area that border each other in the width direction, wherein the edge area adopts a water vapor barrier material. This design enhances the water vapor barrier performance of the encapsulation film, effectively reduces the penetration of water vapor from the edge of the module, and provides more comprehensive protection for the cells inside the photovoltaic module. At the same time, the water vapor barrier material can limit the penetration of water molecules, thereby reducing hydrolysis reactions and ion migration, reducing PID effects, and protecting the performance of the cells.

[0031] The preparation method provided by the present invention effectively combines the materials of the central area and the edge area through hot pressing or multi-zone co-extrusion process to form an integrated packaging film. This method not only improves production efficiency and simplifies the production process, but also optimizes material properties and ensures the integrity and stability of the packaging film.

[0032] The photovoltaic module provided by the present invention, in view of the advantages of the above-mentioned encapsulation film, reduces the damage of water vapor to the battery cell, helps to maintain the photoelectric conversion efficiency of the photovoltaic module, reduces performance degradation, and prolongs the service life. At the same time, by reducing the risk of electrochemical corrosion caused by water vapor, the overall reliability of the module is improved, the long-term maintenance cost is reduced, and the environmental adaptability of the photovoltaic module is enhanced, so that it can better adapt to high humidity and rainy areas, and the market competitiveness of the photovoltaic system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1A schematic diagram of the structure of a packaging film provided by the present invention; Figure 2 It is a schematic diagram of the structure of the T-type die; Figure 3 Schematic diagram of the placement of packaging films in photovoltaic modules. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0036] Hereinafter, the terms "including", "having" and their cognates, which may be used in various embodiments of the present invention, are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the existence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or adding the possibility of one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0037] A first aspect of the present invention provides a packaging adhesive film, comprising a central area and an edge area bordering each other along a width direction; The material of the edge area is a water vapor barrier material.

[0038] The encapsulation film provided by the present invention is divided into a central area and an edge area that border each other in the width direction, wherein the edge area adopts a water vapor barrier material. This design enhances the water vapor barrier performance of the encapsulation film, effectively reduces the penetration of water vapor from the edge of the module, and provides more comprehensive protection for the cells inside the photovoltaic module. At the same time, the water vapor barrier material can limit the penetration of water molecules, thereby reducing hydrolysis reactions and ion migration, reducing PID effects, and protecting the performance of the cells.

[0039] Specifically, the technical effects of the present invention mainly include the following points: Enhanced water vapor barrier performance: By using water vapor barrier materials on the edge of the encapsulation film, the water vapor barrier performance of the edge of the module is significantly improved. This design effectively reduces the possibility of water vapor penetration from the edge of the module, thereby protecting the cells inside the photovoltaic module from water vapor erosion and extending the service life of the module.

[0040] Improve module reliability: The water vapor barrier material in the edge area can provide an additional protective layer for the photovoltaic module, reduce the electrochemical corrosion caused by water vapor, and thus improve the overall reliability of the module. This is especially important for photovoltaic modules working in harsh environments.

[0041] Reducing PID effect: The use of water vapor barrier materials helps to reduce the PID (potential induced degradation) effect. This is because water vapor barrier materials can reduce the penetration of water molecules through the encapsulation film, thereby reducing hydrolysis reactions and ion migration, and protecting the performance of the battery cell.

[0042] Reduced maintenance costs: Due to improved module reliability and durability, this encapsulant film can reduce failures and maintenance requirements caused by moisture in the long run, thereby reducing the maintenance costs of photovoltaic systems.

[0043] Enhanced environmental adaptability: The design of this encapsulation film enables photovoltaic modules to better adapt to various environmental conditions, including high humidity and rainy areas, improving the environmental adaptability and market competitiveness of photovoltaic systems.

[0044] Improve photoelectric conversion efficiency: By reducing the damage of water vapor to the battery cells, the encapsulation film helps maintain the photoelectric conversion efficiency of photovoltaic modules and reduce the performance degradation caused by water vapor.

[0045] Furthermore, the water vapor barrier material includes polyolefin, modified polyolefin, fluorine-containing polymer or chlorine-containing polymer.

[0046] The polyolefin includes polyethylene, polypropylene or polybutylene.

[0047] The modified polyolefin includes silane-modified polyolefin or acid anhydride-modified polyolefin.

[0048] The polyethylene includes linear low-density polyethylene, linear medium-density polyethylene or linear high-density polyethylene.

[0049] The fluorine-containing polymer includes polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer.

[0050] The chlorine-containing polymer includes polyvinylidene chloride.

[0051] When choosing suitable vapor barrier materials, medium-density polyethylene (MDPE) and high-density polyethylene (HDPE) are the first choice due to their excellent performance. These materials have excellent compatibility with the EVA, EPE or POE materials commonly used in the core area, and can achieve strong adhesion during the hot melt process. In addition, they also provide excellent vapor barrier performance and high temperature resistance, which is critical in batteries or other components that need protection. The molecular chain structure of high-density polyethylene has fewer branches and is more regular, which not only enhances its weather resistance, but also helps to maintain its performance stable under various environmental conditions. Therefore, medium-density polyethylene or high-density polyethylene as vapor barrier materials can not only provide effective vapor protection, but also ensure compatibility with the core area material and long-term stability.

[0052] Furthermore, the material of the central area includes EVA, EPE or POE.

[0053] Furthermore, the edge region includes a first edge region and a second edge region.

[0054] The first edge region and the second edge region do not border each other.

[0055] In one embodiment of the present invention, Figure 1 As shown, the packaging film includes a central area 10 and an edge area 20; the packaging film includes a first edge area 22, a central area 10 and a second edge area 24 arranged in sequence along the width direction.

[0056] The width of the first edge region and / or the second edge region is 0.05-10 mm, preferably 0.1-5 mm.

[0057] Typically but not restrictively, the width of the first edge zone and / or the second edge zone can be 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 1mm, 2mm, 3mm, 4mm, 5mm, or any value in the range of 0.05mm to 10mm. Preferably, it can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, i.e. any value in the range of 0.1mm to 5mm.

[0058] The second aspect of the present invention provides a method for preparing the encapsulating adhesive film, wherein the central area and the edge area are integrated by hot pressing to obtain the encapsulating adhesive film.

[0059] or, The central area and the edge area are co-extruded to obtain a packaging film.

[0060] The preparation method provided by the present invention effectively combines the materials of the central area and the edge area through hot pressing or multi-zone co-extrusion process to form an integrated packaging film. This method not only improves production efficiency and simplifies the production process, but also optimizes material properties and ensures the integrity and stability of the packaging film.

[0061] Through hot pressing or multi-zone co-extrusion process, the materials of the center zone and the edge zone are effectively combined to form an integrated encapsulation film. This structure ensures the integrity and stability of the encapsulation film. Hot pressing or multi-zone co-extrusion process can simplify the production process of encapsulation film, reduce production steps, and thus improve production efficiency. Multi-zone co-extrusion process is particularly suitable for continuous production and can achieve efficient large-scale manufacturing. The encapsulation film prepared by hot pressing or co-extrusion process has a more uniform structure, which helps to improve the durability and anti-aging performance of the film, thereby extending the service life of photovoltaic modules.

[0062] Further, the heat pressing is performed by a heat laminator.

[0063] The temperature of the hot pressing is 140-160° C., and the pressure is -100--10 KPa.

[0064] Typically but not limitatively, the temperature of the hot pressing may be 140°C, 145°C, 150°C, 155°C or 160°C, or any value within the range of 140°C to 160°C; the pressure of the hot pressing may be -100KPa, -90KPa, -80KPa, -70KPa, -60KPa, -50KPa, -40KPa, -30KPa, -20KPa or -10KPa, or any value within the range of -100KPa to -10KPa.

[0065] Further, the multi-zone co-extrusion process is: The raw materials of the central area and the raw materials of the edge area are respectively added into different feeding chambers of the screw extruder, and then co-extruded through the T-shaped die mouth, and the materials of different areas are melted together to obtain the packaging film.

[0066] In some embodiments of the present invention, the edge zone raw material is fed into the satellite single screw extruder for extrusion, and the center zone raw material is extruded in the main extruder. Figure 2 As shown in the figure, in the structure of the T-die, the main channel is responsible for guiding the material to various parts of the die, while the satellite extruders are located on both sides of the die and connected to the main channel through the satellite manifold flow channel to ensure that the material can be evenly distributed to each extruder. The design of the center area and the edge area allows the material to be extruded simultaneously in the center and edge areas to form a product with a specific cross-sectional shape. This design not only improves production efficiency, but also ensures the edge quality and overall consistency of the product.

[0067] Optimized edge processing is achieved by using edge wrapping technology while extruding the film in the center. In this method, the two sides of the narrow slot die are equipped with separate "satellite manifold cavities" that feed the material through independent extrusion control units.

[0068] Specifically, the melt delivery pipes and die manifolds are independent of the low-temperature extruded central area material to avoid mutual interference. This independence ensures the stability and quality of the material during the extrusion process. At the die lip of the T-type or narrow slot die, the layers of material are compounded together to form the final product.

[0069] A third aspect of the present invention provides a photovoltaic module, comprising the above-mentioned packaging film.

[0070] The photovoltaic module provided by the present invention, in view of the advantages of the above-mentioned encapsulation film, reduces the damage of water vapor to the battery cell, helps to maintain the photoelectric conversion efficiency of the photovoltaic module, reduces performance degradation, and prolongs the service life. At the same time, by reducing the risk of electrochemical corrosion caused by water vapor, the overall reliability of the module is improved, the long-term maintenance cost is reduced, and the environmental adaptability of the photovoltaic module is enhanced, so that it can better adapt to high humidity and rainy areas, and the market competitiveness of the photovoltaic system is improved.

[0071] Furthermore, the packaging film includes a first packaging film and a second packaging film.

[0072] The first packaging film and the second packaging film are arranged vertically.

[0073] The present invention is further described below by specific examples and comparative examples, but it should be understood that these examples are only used for more detailed description and should not be understood as limiting the present invention in any form. The raw materials used in the examples and comparative examples of the present invention, if no specific conditions are specified, are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially.

[0074] Example 1 This embodiment provides a packaging film, and the preparation process is as follows: 1. Marginal Area 98 parts of SK Orevac® PE 18507 (maleic anhydride grafted high-density polyethylene, melting point 128°C), 1 part of UV absorber Chimassorb 81, 0.5 parts of Tinuvin® 770, and 0.5 parts of Irganox® B 225 were mixed and granulated. The granules were then injected into a single-screw extruder at an extrusion temperature of 180-220°C and cast into a film with a film thickness of 400μm. The film was cut into narrow strips with a width of 3mm as the edge zone film strips.

[0075] 2. Central Area The finished EPE film is cut into 1128mm wide strips as the center film strips.

[0076] 3. Hot pressing Place edge zone mold tapes on both sides of the central zone film tape, and use a hot laminator (temperature 140°C, roller cylinder pressure 6Mpa) to hot-press the edge zone film tape and the central zone film tape together to form an edge-wrapped structure with a total width of 1134mm and a length of 2384mm to obtain a packaging film.

[0077] Example 2 This embodiment provides a packaging film, and the preparation process is as follows: 1. Marginal Area 20 parts of Dow Fusabond M603 (maleic anhydride copolymerized polyethylene, melting point 108°C), 78 parts of JPE HF560 (high-density polyethylene, melting point 134°C), 1 part of ultraviolet absorber Chimassorb 81, 0.5 parts of Tinuvin® 770, and 0.5 parts of Irganox® B 225 were mixed and granulated to obtain maleic anhydride copolymerized high-density polyethylene particles.

[0078] 2. Central Area Use EVA particles as the material of the central area.

[0079] 3. Multi-zone co-extrusion In the satellite single-screw extruder, maleic anhydride copolymer high-density polyethylene particles are added to the satellite extruders on both sides. The extrusion temperature of the satellite extruder is 160°C, and two separate manifolds penetrate into the T-die mouth. EVA particles are added to the main extruder, the extrusion temperature is 95°C, and the mold temperature is 98°C. At the narrow slit T-die mouth, the two materials melt and bond together at the moment of exiting the die. The width of the central area is 1128mm, and the width of the edge areas on both sides is 3mm respectively, to obtain a packaging film.

[0080] The packaging film is cut into sheets with a width of 1134 mm.

[0081] Example 3 This embodiment provides a packaging film, and the preparation process is as follows: 1. Marginal Area 98 parts of SK Orevac® PE 18507 (maleic anhydride grafted high-density polyethylene, melting point 128°C), 1 part of UV absorber Chimassorb 81, 0.5 parts of Tinuvin® 770, and 0.5 parts of Irganox® B 225 were mixed and granulated to obtain maleic anhydride copolymer high-density polyethylene particles.

[0082] 2. Central Area EPE particles are used as the material of the central area.

[0083] 3. Multi-zone co-extrusion In the satellite single-screw extruder, maleic anhydride copolymer high-density polyethylene particles are added to the satellite extruders on both sides. The extrusion temperature of the satellite extruder is 160°C, and two separate manifolds penetrate into the T-die mouth. EPE particles are added to the main extruder, the extrusion temperature is 80°C, the mold temperature is 98°C, and the mold edge is 180°C (water-cooled cavities can be set in the middle and edge of the mold to isolate the temperature difference on both sides). At the narrow T-die mouth, the two materials melt and bond together at the moment of exiting the mold. The width of the center area is 1128mm, and the width of the edge areas on both sides is 3mm respectively, to obtain a packaging film.

[0084] The packaging film is cut into sheets with a width of 1134 mm.

[0085] Example 4 This embodiment provides a packaging film. The difference from Embodiment 2 is that the material of the central area is POE, the extrusion temperature is 95°C during multi-zone co-extrusion, the mold temperature is 100°C, and the remaining raw materials and preparation methods are the same as those in Embodiment 2 and will not be repeated here.

[0086] Example 5 This embodiment provides a packaging film, and the preparation process is as follows: 1. Marginal Area 98 parts of JPE HF560 (high-density polyethylene, melting point 134°C), 1 part of UV absorber Chimassorb 81, 0.5 parts of Tinuvin® 770, and 0.5 parts of Irganox® B 225 were mixed and granulated to obtain high-density polyethylene particles.

[0087] 2. Central Area Use EVA particles as the material of the central area.

[0088] 3. Multi-zone co-extrusion In the satellite single screw extruder, high-density polyethylene particles are added to the satellite extruders on both sides. The extrusion temperature of the satellite extruder is 140°C, and two separate manifolds penetrate into the T-die mouth. EVA particles are added to the main extruder, the extrusion temperature is 95°C, and the mold temperature is 98°C. At the narrow slit T-die mouth, the two materials melt and bond together at the moment of exiting the die. The width of the center area is 1128mm, and the width of the edge areas on both sides is 3mm respectively, to obtain a packaging film.

[0089] The packaging film is cut into sheets with a width of 1134 mm.

[0090] Example 6 This embodiment provides a packaging film. The difference from Embodiment 2 is that the width of the edge areas on both sides is controlled to be 0.05 mm by adjusting the T-shaped mold opening to obtain a packaging film with a width of 1134 mm. The remaining raw materials and preparation methods are the same as those in Embodiment 2 and will not be repeated here.

[0091] Example 7 This embodiment provides a packaging film. The difference from Embodiment 2 is that the width of the edge areas on both sides is controlled to be 10 mm by adjusting the T-shaped mold opening to obtain a packaging film with a width of 1134 mm. The remaining raw materials and preparation methods are the same as those in Embodiment 2 and will not be repeated here.

[0092] Comparative Example 1 This comparative example provides a commercially available packaging film, model number of which is POE cross-linked film TF4.

[0093] Comparative Example 2 This comparative example provides a commercially available packaging film, model number of which is EVA film F406.

[0094] Examples 8-14 and Comparative Examples 3 and 4 These embodiments and comparative examples provide a photovoltaic module, including a front plate, a first packaging film, a solar cell, a second packaging film and a back plate, which are arranged in order from the top layer to the bottom layer.

[0095] The front plate and the back plate are both made of glass, and the first packaging film and the second packaging film are made of the same material, corresponding to the packaging films provided in Example 1-7 and Comparative Example 1-2.

[0096] like Figure 3 As shown, the first packaging film and the second packaging film of Examples 8-14 are arranged at 90 degrees relative to each other in their respective MD directions, and edge areas are provided around the solar cell.

[0097] Comparative Example 5 The present comparative example provides a photovoltaic module, comprising a front plate, a first packaging film, a solar cell, a second packaging film and a back plate which are arranged in sequence from the top layer to the bottom layer.

[0098] Among them, the front plate and the back plate are both made of glass, the first packaging film and the second packaging film are made of the same material, which is the packaging film provided in Comparative Example 1, and finally the photovoltaic module is packaged on the four sides with butyl glue.

[0099] Test Example 1 The photovoltaic modules obtained in the embodiments and comparative examples were subjected to performance tests.

[0100] Damp heat test: The test conditions are 85°C and 85% relative humidity, and the duration is 2000 hours.

[0101] The obtained data are shown in Table 1 below.

[0102] Table 1

[0103] In comparison with Comparative Examples 3 and 4, Examples 8 and 9 show significant advantages. Comparative Examples 3 and 4 are easily corroded by water vapor at the edges, which negatively affects the power generation efficiency of the battery and makes it unable to maintain the best state.

[0104] Compared with Comparative Example 5, Examples 8 and 9 also show better performance. The process of Comparative Example 5 is relatively complicated, the cost is relatively high, and its water vapor barrier effect is not ideal. In long-term use, the edges around Comparative Example 5 are also easily corroded by water vapor, which also reduces the power generation efficiency of the battery.

[0105] Without changing the existing component assembly lamination process, Examples 8 and 9 effectively prevent water vapor from invading from the edges by wrapping and filling the four edges of the component with high-density polyethylene material with extremely strong water-blocking properties, thereby protecting the battery and maintaining its power generation efficiency.

[0106] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A packaging film, characterized in that: It includes a central area and an edge area bordering each other in the width direction; The material of the edge area is a water vapor barrier material; The water vapor barrier material includes polyolefin, modified polyolefin, fluorine-containing polymer or chlorine-containing polymer; The material of the central area includes EVA, EPE or POE.

2. The packaging film according to claim 1, characterized in that: The polyolefin includes polyethylene, polypropylene or polybutylene; The modified polyolefin includes silane-modified polyolefin or anhydride-modified polyolefin; The polyethylene includes linear low-density polyethylene, linear medium-density polyethylene or linear high-density polyethylene.

3. The packaging film according to claim 1, characterized in that: The fluorine-containing polymer includes polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer; The chlorine-containing polymer includes polyvinylidene chloride.

4. The encapsulation film according to any one of claims 1 to 3, characterized in that: The edge region includes a first edge region and a second edge region; The first edge region and the second edge region do not border each other.

5. The packaging film according to claim 4, characterized in that: The packaging film comprises a first edge region, a center region and a second edge region sequentially arranged along the width direction; The width of the first edge region and / or the second edge region is 0.05-10 mm.

6. A method for preparing the encapsulation film according to any one of claims 1 to 5, characterized in that: The central area and the edge area are integrated by heat pressing to obtain a packaging film; or, The central area and the edge area are co-extruded to obtain a packaging film.

7. The preparation method according to claim 6, characterized in that: The heat pressing is performed by a heat laminator; The temperature of the hot pressing is 140-160° C., and the pressure is -100--10 KPa.

8. The preparation method according to claim 6, characterized in that: The process of multi-zone co-extrusion is: The raw materials of the central area and the raw materials of the edge area are respectively added into different feeding chambers of the screw extruder, and then co-extruded through the T-shaped die mouth, and the materials of different areas are melted together to obtain the packaging film.

9. A photovoltaic module, characterized in that: The encapsulation film comprises the encapsulation film according to any one of claims 1 to 5.

10. The photovoltaic module according to claim 9, characterized in that: The packaging film includes a first packaging film and a second packaging film; The first packaging film and the second packaging film are arranged vertically.

Images