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. A packaging adhesive film comprises a first adhesive film layer and a second adhesive film layer which are arranged in a staggered mode in the first direction and located on the same plane, and the first adhesive film layer and the second adhesive film layer are integrally formed. Wherein the adhesive film layers on the two sides are made of the same material. The packaging adhesive film is good in water blocking effect, achieves the water blocking effect of using pure POE, and is low in cost. In the production process of the packaging adhesive film, the white high-reflection filler is added into the POE adhesive film layer, so that the output power of the photovoltaic module can be improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of encapsulation films, and particularly to an encapsulation film, a preparation method thereof, and a photovoltaic module. Background Art

[0002] At present, the materials commonly used in the industry for photovoltaic module encapsulation films mainly include EVA, POE, and PVB. The encapsulation films have structures of pure A or B or AB co-extrusion, such as ABA, BAB, AB. Usually, A represents ethylene-vinyl acetate copolymer (abbreviated as EVA), and B represents polyolefin elastomer (POE). EVA exists in all these structures, and the water vapor transmission rate of EVA is as high as 20 g / ㎡*24h. When water vapor molecules reach the edge of the material, they will penetrate along the direction of the material body. During the process of encapsulating heterojunction HJT cells into photovoltaic modules, the water vapor transmission rate has a significant impact on the performance and lifespan of heterojunction photovoltaic modules.

[0003] Due to structures such as the TCO film layer and amorphous silicon film layer and low-temperature processes, heterojunction cells are highly sensitive to water vapor. Therefore, the water vapor transmission rate (WVTR) of the encapsulation material needs to be strictly controlled below 5 g / ㎡*24h to ensure that the product meets the reliability tests under the IEC61215 and IEC61730 international standards.

[0004] High water vapor penetration may lead to a decline in battery performance, an increase in battery attenuation, and affect the long-term stability and reliability of the battery. However, the current encapsulation film design cannot meet the requirements of heterojunction cells for the water vapor transmission rate. In addition, due to the low water vapor transmission rate of the POE material, which is as low as 2 g / ㎡*24h, if the POE material is used alone, the reliability of the fabricated photovoltaic product is guaranteed, but the cost is high, which is not conducive to enhancing the product competitiveness. Summary of the Invention

[0005] The present disclosure provides an encapsulation film, a preparation method thereof, and a photovoltaic module to solve at least one of the technical problems existing in the prior art.

[0006] According to a first aspect of the present disclosure, the present invention provides an encapsulation film, including a first film layer and a second film layer that are alternately arranged along a first direction and are in the same plane, and the first film layer and the second film layer are integrally formed; wherein, the materials of the film layers on both sides are the same.

[0007] In an implementable embodiment, the first film layer and the second film layer are co-extruded and formed;

[0008] Alternatively, the first film layer and the second film layer are thermally pressed and compounded to form the encapsulation film.

[0009] In one feasible embodiment, the first adhesive film layer is a POE adhesive film layer, the second adhesive film layer is an EVA adhesive film layer, and the adhesive film layers on both sides are POE adhesive film layers.

[0010] In one feasible embodiment, the width of the POE adhesive film layer is 5 - 30 mm; the width of the EVA adhesive film layer is 162 - 230 mm.

[0011] In one feasible embodiment, the width of the POE adhesive film layers on both sides is 5 - 30 mm, and the width of the POE adhesive film layer in the middle is 5 - 15 mm.

[0012] In one feasible embodiment, the width of the EVA adhesive film layer is 182 ± 20 mm; or the width of the EVA adhesive film layer is 210 ± 20 mm.

[0013] In one feasible embodiment, the crosslinking degree of the POE adhesive film layer is 15% - 45%.

[0014] According to the second aspect of the present disclosure, the present invention provides a method for preparing the encapsulation adhesive film, and the preparation method includes:

[0015] Prepare POE production raw materials, and then input the POE production raw materials into the second raw material pipeline in a vacuum environment;

[0016] Prepare EVA production raw materials, and then input the EVA production raw materials into the first raw material pipeline in a vacuum environment; wherein the first raw material pipeline and the second raw material pipeline are independent pipelines respectively;

[0017] The first raw material pipeline and the second raw material pipeline supply materials to the feed bin of the extruder respectively, and are cast and extruded into shape to obtain the encapsulation adhesive film;

[0018] Or, the preparation method includes:

[0019] Prepare POE production raw materials, and then vacuum transport the POE production raw materials to the feed bin of the extruder, and cast and extrude into shape to obtain the POE adhesive film layer;

[0020] Prepare EVA production raw materials, and then vacuum transport the EVA production raw materials to the feed bin of the extruder, and cast and extrude into shape to obtain the EVA adhesive film layer;

[0021] Thermally press and compound the POE adhesive film layer and the EVA adhesive film layer to form the encapsulation adhesive film.

[0022] In one feasible embodiment, it further includes: performing electron beam irradiation on the POE adhesive film layer of the encapsulation adhesive film, with the irradiation dose being 15 kGy - 130 kGy, and the irradiation dose is slowly accumulated and increased until the crosslinking degree of the POE adhesive film layer reaches 15% - 45%.

[0023] According to a third aspect of the present disclosure, there is provided a photovoltaic module including the encapsulation adhesive film described above, or the encapsulation adhesive film obtained by the preparation method described above.

[0024] Compared with the prior art, the advantages of the present application are as follows: 1) In the encapsulation adhesive film of the present application, the first adhesive film layer and the second adhesive film layer are arranged alternately. The first adhesive film layer is a POE adhesive film layer, and the second adhesive film layer is an EVA adhesive film layer, so that the encapsulation adhesive film of the present application has good water resistance, achieving the water resistance effect of using pure POE, and the cost is low. 2) During the production process of the encapsulation adhesive film of the present application, white high-reflection fillers are added to the POE adhesive film layer, which can improve the output power of the photovoltaic module. 3) White high-reflection fillers or black materials are added to the POE production raw materials of the present application, so that during the production process of the encapsulation adhesive film, it is convenient to identify and monitor the product quality, and it is convenient for the application side of the photovoltaic module to use. 4) When the encapsulation adhesive film of the present application is assembled into a photovoltaic module, under lamination, the encapsulation adhesive film of the present application can be well adhered to the glass, preventing water vapor from entering the interior of the photovoltaic module along the interface between the glass and the encapsulation adhesive film, and extending the service life of the photovoltaic module.

[0025] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present disclosure, nor is it used to limit the scope of the present disclosure. Other features of the present disclosure will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features, and advantages of the exemplary embodiments of the present disclosure will become easily understandable. In the drawings, several embodiments of the present disclosure are shown in an exemplary rather than restrictive manner, wherein:

[0027] In the drawings, the same or corresponding reference numerals represent the same or corresponding parts.

[0028] Figure 1 Shows the structural schematic of the first encapsulation adhesive film of the present disclosure Figure 1 ;

[0029] Figure 2 Shows the structural schematic of the first encapsulation adhesive film of the present disclosure Figure 2 ;

[0030] Figure 3 Shows the structural schematic of the second encapsulation adhesive film of the present disclosure Figure 1 ;

[0031] Figure 4 Shows the structural schematic of the second encapsulation adhesive film of the present disclosure Figure 2 ;

[0032] Figure 5 Shows the extrusion structure diagram of the encapsulation adhesive film of the first preparation method of the present disclosure;

[0033] Figure 6 Shows the extrusion structure diagram of the POE film layer of the second preparation method of the present disclosure;

[0034] Figure 7 Shows the schematic structural diagram during irradiation of the POE film layer of the second preparation method of the present disclosure;

[0035] Figure 8 Shows the extrusion structure diagram of the EVA film layer of the second preparation method of the present disclosure;

[0036] Figure 9 Shows the structural diagram during hot pressing and compounding of the encapsulation film of the second preparation method of the present disclosure;

[0037] Figure 10 Shows the schematic structural diagram of the photovoltaic module of the present disclosure.

[0038] Explanation of the reference numerals in the drawings: 1 - POE film layer, 2 - EVA film layer, 3 - first raw material pipeline, 4 - extrusion wheel, 5 - second raw material pipeline, 6 - electron beam, 7 - glass, 8 - encapsulation film, 9 - cell, 10 - third raw material pipeline, 11 - roller. Detailed implementation manners

[0039] To make the purpose, features, and advantages of the present disclosure more obvious and understandable, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present disclosure.

[0040] Currently, due to the relatively late large-scale industrialization of the heterojunction battery encapsulation technology, with the maturity of the technology and the intensification of competition, low-cost batteries adopt low-silver paste technology, etc., which have more stringent requirements for water resistance and higher requirements for controlling the product production cost.

[0041] Currently, the longitudinal PE, PEP, EPE, etc. structures adopted in the market are the main types of large-scale applications. In the transverse structure, the large-scale application in the market is very small. At the same time, in the application of the encapsulation film product in the photovoltaic module, the product is prone to delamination problems in the environmental test line. The main reason is that in the manufacturing process of the photovoltaic module, the crosslinking reaction rate of EVA is faster than that of POE. Therefore, in the manufacturing process of the same photovoltaic module product, the crosslinking degree of EVA has reached more than 85%, while the crosslinking degree of PEO has not reached 60%. The higher the crosslinking degree, the more sufficient the material reaction, the higher the formed bond energy, and the more solid the network structure formed by the material.

[0042] Therefore, we came up with the idea of using the horizontal combination of multiple POEs and EVA to achieve the water-blocking technology. By adopting the technology of directional local POE pre-crosslinking and fusion in EVA, the pain points at the application end are solved.

[0043] Based on this, according to an embodiment of the present disclosure, as Figures 1-4 shown, the present invention provides an encapsulation film, which includes a first film layer and a second film layer that are arranged alternately along a first direction and are in the same plane, and the first film layer and the second film layer are integrally formed; wherein, the materials of the film layers on both sides are the same.

[0044] In this embodiment, the so-called first direction is Figure 1 the X direction shown, and this X direction is a direction perpendicular to the winding direction of the encapsulation film. The second direction is Figure 1 the Y direction shown, and this Y direction is the winding direction of the encapsulation film.

[0045] In some embodiments, the first film layer and the second film layer are co-extruded and formed. Through co-extrusion molding, the encapsulation film can be prepared, and the process is simple and easy for large-scale production. Or, the first film layer and the second film layer are hot-pressed and compounded to form the encapsulation film. That is, the first film layer and the second film layer are respectively prepared first, and then according to the structure and size of the encapsulation film, the first film layer and the second film layer are cut and alternately stacked, and then formed into the encapsulation film through hot-pressing and compounding.

[0046] In some embodiments, the first film layer is a POE film layer 1, the second film layer is an EVA film layer 2, and the film layers on both sides are POE film layers 1.

[0047] The POE film layer 1 is a high water-blocking film layer. The POE film layer 1 with high water-blocking effect is distributed on both sides of the EVA film layer 2, which can effectively prevent water vapor from infiltrating, improve the water-blocking effect of the encapsulation film, ensure the safety of the photovoltaic module in high-temperature and high-humidity environments and long-term aging resistance, and extend the service life of the photovoltaic module. Thus, the encapsulation film of the present application has a good water-blocking effect, reaching the water-blocking effect of using pure POE, and has a low cost, improving the product competitiveness. The POE film layers of the present application are horizontally staggered, which has a multiple protection effect on the photovoltaic cells of the photovoltaic module. Even if water vapor penetrates in at the edge, it does not affect the power generation effect of other independent battery strings.

[0048] In some embodiments, the width of the POE film layer 1 is 5-30 mm; the width of the EVA film layer 2 is 162-230 mm.

[0049] For example, as Figure 2 、 Figure 4As shown, the width L1 of the POE film layers 1 on both sides is 5 - 30 mm, and the width L3 of the POE film layer 1 in the middle is 5 - 15 mm. Exemplarily, the widths of the POE film layers are 5 mm, 8 mm, 11 mm, 15 mm, 18 mm, 20 mm, 23 mm, 26 mm, 30 mm;

[0050] Preferably, the width L2 of the EVA film layer 2 is 182 ± 20 mm; or the width of the EVA film layer L2 is 210 ± 20 mm.

[0051] The width L1 of the POE film layers 1 at the two side edge positions is positively correlated with water resistance. The larger the edge width, the higher the water resistance coefficient. Therefore, in this application, the width L1 of the POE film layers 1 at the two side edges is limited to 5 - 30 mm, which can better achieve the water resistance effect.

[0052] The width L2 of the EVA film layer 2 is set according to the standard size of the photovoltaic cell. A reasonable size is the width of the cell, so as to minimize the cost. Therefore, when the width of the EVA film layer 2 is limited to 162 - 230 mm and combined with the width of the POE film layer 1, it can better achieve the water resistance effect while reducing the production cost.

[0053] For example, since the width of the EVA film layer is determined according to the width of the cell, the number of the POE film layers and the EVA film layers arranged alternately along the first direction is determined according to the width of the cell. Therefore, in this application, the number of the POE film layers and the EVA film layers is not particularly limited. Exemplarily, as Figures 1-2 shown, the number of the POE film layers is 6 and the number of the EVA film layers is 5; as Figures 3-4 shown, the number of the POE film layers is 7 and the number of the EVA film layers is 6.

[0054] In some embodiments, the crosslinking degree of the POE film layer 1 is 15 - 45%. In order to ensure low fluidity of the POE film layer, the POE film layer 1 is pre - crosslinked to make the crosslinking degree of the POE film layer reach 15 - 45%. In this application, the crosslinking degree of the POE film layer reaches 15% - 45% through the local material directional pre - crosslinking process, solving the problem of delamination of different films in the reliability test of photovoltaic modules and ensuring the life of the modules.

[0055] In some embodiments, the POE film layer 1 contains white high - reflectivity filler, or the POE film layer 1 contains black material.

[0056] The POE film layer contains white high-reflection fillers or black materials, which facilitates process monitoring and width identification, enhances the effect of light between solar cells, and increases the aesthetics of photovoltaic modules. In addition, using white high-reflection fillers can simultaneously increase the power of photovoltaic modules by 0.8% - 2.2%. Black materials are mainly used to produce black photovoltaic products and improve the aesthetics of the products.

[0057] When the POE film layer 1 contains white high-reflection fillers, the color of the POE film layer 1 is white. The white POE film layer 1 is arranged in a staggered manner along the first direction. Thus, the POE film layer with staggered white gaps along the first direction can block water while increasing the function of reflected light, replacing the existing enamel coating or reflective film, reducing production costs, and avoiding the risk of shedding caused by reflective materials such as existing enamel coatings or additional reflective films after long-term operation. If black is used, it is for enhancing the aesthetics of black products. The POE film layer arranged in a staggered manner as gaps along the first direction can achieve the effect of blocking water vapor, and at the same time has multiple protection effects on the photovoltaic cells inside the photovoltaic module. Even if water vapor penetrates from the edge, it does not affect the power generation effect of other independent battery strings.

[0058] For example, the white high-reflection filler is one or a mixture of titanium dioxide and calcium carbonate;

[0059] The black material is one or a mixture of iron oxide black, iron chromium black, and carbon black.

[0060] In a second aspect, according to an embodiment of the present disclosure, the present invention also provides a method for preparing the above encapsulation film, which includes:

[0061] Prepare POE production raw materials, where the POE production raw materials contain white high-reflection fillers or black materials; then input the POE production raw materials into the second raw material pipeline 5 in a vacuum environment;

[0062] Prepare EVA production raw materials, and then input the EVA production raw materials into the first raw material pipeline 3 in a vacuum environment; where the first raw material pipeline and the second raw material pipeline are independent pipelines;

[0063] Feed the extrusion machine feed bin at a feeding rate of 0.2 - 20 parts by weight per second and a feeding temperature of 80 - 105°C for the first raw material pipeline, and a feeding rate of 0.2 - 20 parts by weight per second and a feeding temperature of 80 - 105°C for the second raw material pipeline, and perform cast extrusion molding to obtain the encapsulation film.

[0064] Using the method of the present application, an encapsulation film with a uniform thickness can be obtained by cast extrusion. The thickness of the encapsulation film is 0.2 - 0.9 mm. The structure diagram is as Figures 1-4As shown in the figure. The width L1 of the POE film layers 1 located at both side edges is 5 mm to 30 mm, and the color of the POE film layer is white or black. The width L3 of the POE film layer 1 located in the middle is 5 mm to 15 mm, and the color of the film is white or black. The width L2 of the EVA film layer is 182 mm ± 20 mm or 210 mm ± 20 mm.

[0065] In the method of this application, POE and EVA will be intertwined and integrated in a molten state. According to the principle of similar compatibility, mainly due to their similar chemical compositions and similar molecular chain structures. Both POE and EVA are polymers mainly composed of olefin monomers. POE is mainly copolymerized from ethylene and α-olefins such as octene, while EVA is copolymerized from ethylene and vinyl acetate. They both contain ethylene units and have a certain similarity in molecular structure, which makes them easier to fuse with each other under heating conditions and can diffuse and mix with each other more easily when heated. At the same time, their molecular chains with similar structures are usually linear or slightly branched structures, which makes them easier to entangle and intertwine with each other when heated.

[0066] Therefore, in this application, the POE film layer and the EVA film layer are arranged alternately, with the POE film layer set on both sides. Due to the similar compatibility of the POE film layer and the EVA film layer, when the encapsulation film assembles a photovoltaic module, under lamination and heat sealing, the encapsulation film of this application can be perfectly bonded to the glass, preventing water vapor from entering the interior of the photovoltaic module along the interface between the glass and the encapsulation film, and extending the service life of the photovoltaic module.

[0067] In the method of this application, EVA reacts faster than POE during the thermal curing process. Mainly, the vinyl acetate groups on the EVA molecular chain can provide more reactive sites. During the cross-linking process, common cross-linking agents such as peroxides can react with the carbon-carbon double bonds (from VA groups) and other active hydrogen atoms on the EVA molecular chain. Since there are more active sites available for the cross-linking agent to attack, the cross-linking reaction can be quickly initiated and continue, thus accelerating the cross-linking speed. While the number of active sites on the POE molecular chain is relatively small. The main reactive sites are the carbon-carbon double bonds in the molecular chain, but the content of double bonds in the POE molecular chain is usually less than the active sites provided by the VA groups in EVA. This results in relatively fewer reaction opportunities for the cross-linking agent in POE, and the reaction speed is relatively slow.

[0068] Therefore, in this application, by setting multiple POE structures along the first direction (i.e., the transverse direction), and at the same time adding the pre-crosslinking process technology, it is possible to achieve that at the time point of sufficient cross-linking of EVA, POE can also reach sufficient cross-linking, which is an important innovation point of this application.

[0069] In the method of this application, a white high-reflection filler or a black material is added to the POE production raw materials. The purposes are as follows: First, it can increase the utilization of the reflected light in the gaps between the battery strings in the photovoltaic module, thereby improving the power and conversion efficiency of the photovoltaic module. Second, it can distinguish and control the widths of POE and EVA in terms of appearance. POE particles and EVA particles are transparent and colorless by themselves, and it is easy to control mass production using white or black.

[0070] In this embodiment, in order to extrude and form the POE production raw materials and the EVA production raw materials separately at the same time, the single raw material transfer pipeline in front of the screw extruder of the film production equipment is transformed into an independent branch feeding system. As Figure 5 shown, B1, B2, B3, B4, B5, Bn are independent branch pipelines of the B feeding pipeline (i.e., the second raw material pipeline 5, used to supply POE production raw materials), and A1, A2, A3, A4, An are independent branch pipelines of the A feeding pipeline (i.e., the first raw material pipeline 3, used to supply EVA production raw materials).

[0071] Preferably, the POE production raw materials include, by weight parts, 53.1 - 64.9 parts of ethylene, 25.2 - 30.8 parts of octene, 9 parts of white high-reflection filler or black material, 0.20 part of tris(2,4-di-tert-butylphenyl) phosphite, 0.10 part of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 0.3 part of light stabilizer, 0.0045 part of catalyst, and 0.2 part of auxiliary tackifier.

[0072] More preferably, the POE production raw materials include, by weight parts (phr), 59.0 parts of ethylene, 28.0 parts of octene, 9 parts of white high-reflection filler or black material, 0.20 part of tris(2,4-di-tert-butylphenyl) phosphite, 0.10 part of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 0.3 part of light stabilizer, 0.0045 part of catalyst, and 0.2 part of auxiliary tackifier. After mixing the above raw materials evenly, they are input into the second raw material pipeline through a vacuum transfer system, and the outlet of the second raw material pipeline is connected to the feed bin of the extruder.

[0073] Further, the light stabilizer is C 28 H 50 N 2 O 4 . The white high-reflection filler is titanium dioxide or calcium carbonate.

[0074] Preferably, the raw materials for EVA production include, by weight parts, 62.1 - 75.9 parts of ethylene, 27 - 33 parts of ethylene acetate, 0.5 part of tert-butyl peroxy-2-ethylhexyl carbonate, 0.5 part of γ-methacryloxypropyltrimethoxysilane, 0.2 part of 2,6-di-tert-butyl-p-cresol, 0.25 part of dimethylaminoethyl acrylate, and 0.25 part of dimethylaminoethyl methacrylate.

[0075] More preferably, the raw materials for EVA production include, by weight parts (phr), 69 parts of ethylene, 30 parts of ethylene acetate, 0.5 part of tert-butyl peroxy-2-ethylhexyl carbonate, 0.5 part of γ-methacryloxypropyltrimethoxysilane, 0.2 part of 2,6-di-tert-butyl-p-cresol, 0.25 part of dimethylaminoethyl acrylate, and 0.25 part of dimethylaminoethyl methacrylate. After mixing the above raw materials evenly, they are input into the first raw material pipeline through a vacuum transfer system, and the outlet of the first raw material pipeline is connected to the feed bin of the extruder.

[0076] Among them, in the preparation of the encapsulation film in this application, when the screw extruder is started, the feeding rate of the A branch pipeline is 0.2 - 20 weight parts / second, and the feeding rate of the B branch pipeline is 0.2 - 20 weight parts / second. According to the width of the equipment required, the supply rate and supply amount of the A and B branch pipelines are adjusted, and the extrusion temperature is 80 - 105°C. The material is extruded and formed through the extrusion wheel 4.

[0077] In some embodiments, the preparation method of this application further includes: irradiating the POE film layer 1 of the encapsulation film with an electron beam, with an irradiation dose of 15 kGy - 130 kGy, and the irradiation dose is slowly and cumulatively increased until the crosslinking degree of the POE film layer 1 reaches 15% - 45%.

[0078] After the irradiation of the encapsulation film is completed, it is cut according to the size, and then wound and packaged, and the production is completed.

[0079] Specifically, after the film roller with a uniform thickness of 0.2 mm - 0.9 mm formed by casting extrusion is embossed, it is irradiated with an electron beam (as shown in Figure 4 shown, electron beam 6), and the irradiation only covers the POE position of the film, that is, Figure 4 in, the marked widths are L1 and L3 positions. The irradiation coverage width L1 of the left / right POE film layer 1 is 5 mm - 30 mm. The irradiation coverage width L3 of the middle POE film layer position is 5 - 15 mm. The electron beam irradiation dose of all POE positions is 15 kGy - 130 kGy, and the irradiation dose is slowly and cumulatively increased until the crosslinking degree of the film POE reaches 15% - 45%.

[0080] In some embodiments, the encapsulation film of this application can also be prepared by a second method, which specifically includes:

[0081] Configure the raw materials for POE production, and then vacuum transport the POE production raw materials to the feed bin of the extruder, and obtain the POE film layer by casting and extrusion molding;

[0082] Configure the raw materials for EVA production, and then vacuum transport the EVA production raw materials to the feed bin of the extruder, and obtain the EVA film layer by casting and extrusion molding;

[0083] Thermally press and laminate the POE film layer and the EVA film layer to form the encapsulation film.

[0084] For example, configuring the raw materials for POE production, and then vacuum transporting the POE production raw materials to the feed bin of the extruder, and obtaining the POE film layer by casting and extrusion molding includes:

[0085] As shown in Figure 6, using a single screw extruder, after uniformly mixing the POE production raw materials, that is, C 2 H 4 (ethylene) 59.0 parts, C 8 H 16 (octene) 28.0 parts, white high-reflection filler or black material (such as titanium dioxide) 9 parts, tris(2,4-di-tert-butylphenyl) phosphite 0.20 parts, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] 0.10 part, light stabilizer C 28 H 50 N 2 O 4 0.3 part, catalyst 0.0045 part, auxiliary tackifier 0.2 part, mix evenly according to the precise ratio, and introduce it into the third raw material pipeline 10 through the vacuum transmission system. The discharge port of the third raw material pipeline 10 is connected to the feed bin of the extruder; start the screw extruder, the extrusion temperature is 80-105°C, and obtain the POE film layer 1 by casting and extrusion through the extrusion wheel 4. The thickness of the POE film layer is 0.2 mm - 0.9 mm.

[0086] Furthermore, before the thermal pressing and lamination, it also includes irradiating the POE film layer 1 with an electron beam of 6, as Figure 7 shown, the electron beam irradiation dose is 15 kGy - 130 kGy, and the irradiation dose increases slowly and cumulatively until the POE crosslinking degree reaches between 15% and 45%.

[0087] For example, configuring the raw materials for EVA production, and then vacuum transporting the EVA production raw materials to the feed bin of the extruder, and obtaining the EVA film includes:

[0088] As Figure 8 shown, using a single screw extruder, after uniformly mixing the EVA production raw materials, that is, C 2 H 4 (ethylene) 69 parts, C4 H 6 O 2 (Vinyl acetate) 30 parts, tert-butyl peroxy-2-ethylhexyl carbonate 0.5 part, γ-methacryloxypropyltrimethoxysilane 0.5 part, 2,6-di-tert-butyl-p-cresol 0.2 part, dimethylaminoethyl acrylate 0.25 part, dimethylaminoethyl methacrylate 0.25 part, are mixed evenly according to precise proportions. They are fed into the third raw material pipeline 10 through a vacuum transfer system, and the discharge port of the third raw material pipeline 10 is connected to the feed bin of an extruder; the screw extruder is started, and the extrusion temperature is 80-105 °C. It is extruded and formed by a casting wheel 4 to obtain an EVA film layer 2, and the thickness of the EVA film layer is 0.2 mm - 0.9 mm.

[0089] For example, laminating and hot-pressing the POE film layer and the EVA film layer to form the encapsulation film includes: cutting the POE film layer and the EVA film layer respectively according to the size and structure of the encapsulation film, and stacking the POE film layer and the EVA film layer alternately on an adsorption heating rolling platform according to the designed structure of the encapsulation film. The platform temperature is 80 - 120 °C. After they enter the molten state, the POE film layer 1 and the EVA film layer 2 are immediately compounded into one body by a roller 11, and finally the encapsulation film is obtained, as Figure 9 shown.

[0090] According to the third aspect of the present disclosure, as Figure 10 shown, the embodiments of the present disclosure provide a photovoltaic module, including an encapsulation film, or the encapsulation film obtained by the preparation method described above. The photovoltaic module with this encapsulation film can also achieve a better water blocking effect while increasing the output power of the photovoltaic module and reducing the production cost of the photovoltaic module. And during the assembly process of the photovoltaic module with the encapsulation film of the present application, when the encapsulation film, glass, and solar cell are laminated and heat-sealed, the encapsulation film can adhere well to the glass, preventing water vapor from entering the interior of the photovoltaic module from the interface and both sides of the two, and extending the service life of the photovoltaic module.

[0091] The encapsulation film of the present application is a segmented structure along the first direction (high water blocking film (POE) + conventional film (EVA) + high water blocking film (POE)) for internal encapsulation of photovoltaic modules. The encapsulation film is laid on the module, and each solar cell string forms an independent POE water blocking unit, and the POE width is 5 - 30 mm.

[0092] As Figure 10 shown, the photovoltaic module is a laminated structure, including glass 7, encapsulation film 8, solar cell 9, encapsulation film 8, and glass 7 stacked in sequence from top to bottom.

[0093] Since the encapsulation film of the present application has a high water barrier effect and can meet the requirements of different types of solar cells for water vapor transmission rate, the photovoltaic modules assembled from the encapsulation film of the present application and different types of solar cells also have a high water barrier effect, ensuring the stability of the performance of the photovoltaic modules and prolonging the service life of the photovoltaic modules. Among them, the so-called different types of solar cells include, but are not limited to, aluminum back surface field (BSF) solar cells, PERC solar cells, heterojunction cells, TOPCon cells, and IBC cells.

[0094] For example, when an encapsulation film and a heterojunction cell are assembled to obtain a heterojunction photovoltaic module, water vapor can be blocked outside, ensuring the stability and reliability of the long-term operation of the heterojunction photovoltaic module, prolonging its service life, and improving the core competitiveness of the product.

[0095] The following further describes the present application in detail with specific embodiments:

[0096] Example 1

[0097] (1) As Figures 1-2 shown, an encapsulation film 8 includes a POE film layer 1 and an EVA film layer 2 that are arranged alternately along the first direction (X direction) and are in the same plane. The POE film layer 1 and the EVA film layer 2 are co-extruded. Among them, the film layers on both sides are POE film layers 1; the width L1 of the POE film layers on both sides is 18 mm, the width L3 of the POE film layer in the middle is 5 mm; and the width L2 of the EVA film layer in the middle is 208 mm.

[0098] (2) The preparation method of the encapsulation film includes:

[0099] Step (1), configuring POE production raw materials: The POE production raw materials include, by weight, 59.0 parts of ethylene, 28.0 parts of octene, 9 parts of titanium dioxide, 0.20 part of tris(2,4-di-tert-butylphenyl) phosphite, 0.10 part of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], 0.3 part of light stabilizer C28H50N2O4, 0.0045 part of catalyst (methylaluminoxane), and 0.2 part of auxiliary tackifier (vinyltrimethoxysilane); after mixing evenly, the POE production raw materials are input into the second raw material pipeline through a vacuum transfer system, and the outlet of the second raw material pipeline is connected to the feed bin of the extruder.

[0100] Step (2), configure the raw materials for EVA production: The raw materials for EVA production include, by weight, 69 parts of ethylene, 30 parts of ethylene acetate, 0.5 part of tert-butyl peroxy-2-ethylhexyl carbonate, 0.5 part of γ-methacryloxypropyltrimethoxysilane, 0.2 part of 2,6-di-tert-butyl-p-cresol, 0.25 part of dimethylaminoethyl acrylate, and 0.25 part of dimethylaminoethyl methacrylate; after mixing evenly, the raw materials for EVA production are input into the first raw material pipeline through a vacuum transfer system, and the outlet of the first raw material pipeline is connected to the feed bin of the extruder.

[0101] Step (3), feed the feed bin of the extruder at a feeding rate of 0.2 - 20 parts by weight per second and a feeding temperature of 90°C for the first raw material pipeline, and a feeding rate of 0.2 - 20 parts by weight per second and a feeding temperature of 90°C for the second raw material pipeline, and perform cast extrusion molding to obtain the encapsulation film.

[0102] Step (4), perform electron beam irradiation on the POE film layer of the encapsulation film, with an irradiation dose of 15 kGy - 130 kGy, and the irradiation dose is slowly accumulated until the crosslinking degree of the POE film layer reaches 32%.

[0103] (III) Preparation of photovoltaic modules, including manufacturing photovoltaic modules by arranging the encapsulation film 8, glass 7, and solar cells 9 according to the Figure 10 structure shown.

[0104] (IV) Performance testing of photovoltaic modules:

[0105] Perform performance testing on the photovoltaic module prepared in Example 1 of the present invention and the photovoltaic module with a conventional film, and the results are shown in Table 1.

[0106] Table 1 Performance test results of the photovoltaic module in Example 1 of the present invention and the existing conventional photovoltaic modules

[0107]

[0108]

[0109] Among them, in Table 1, the serial number refers to the results obtained respectively after multiple parallel tests on the corresponding products. Pmpp represents the maximum power point, Isc represents the short-circuit current, Voc represents the open-circuit voltage, Impp represents the current at the maximum power point, Vmpp represents the voltage at the maximum power point, and FF represents the fill factor. Among them, the conventional photovoltaic module is the G12 series of photovoltaic modules with better performance on the current market.

[0110] As can be seen from Table 1 above, the maximum power point pmpp, short-circuit current isc, open-circuit voltage voc, maximum power point current impp, and fill factor ff of the photovoltaic module of this application are all greater than those of conventional photovoltaic modules. From the test data in Table 1, it is found that the encapsulation film of this application can increase the output power of the photovoltaic module product by 2.06%, and the average short-circuit current Isc of the photovoltaic module product increases by 1.45% on average. This shows that the encapsulation film of this application can achieve a certain improvement effect on the power of the photovoltaic module product.

[0111] It should be understood that various forms of the processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this disclosure can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solutions disclosed in this disclosure can be achieved. No limitation is imposed herein.

[0112] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of these features. In the description of this disclosure, "a plurality" means two or more unless otherwise specifically defined.

[0113] The orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of this application.

[0114] The description of terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this disclosure. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0115] As described above, this is only a specific implementation of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present disclosure can easily think of changes or substitutions, which should all be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claimed rights.

Claims

1. A packaging film, characterized in that: It comprises a first adhesive film layer and a second adhesive film layer which are staggered along a first direction and are located in the same plane, wherein the first adhesive film layer and the second adhesive film layer are integrally formed; wherein the adhesive film layers on both sides are made of the same material.

2. The packaging film according to claim 1, characterized in that: The first adhesive film layer and the second adhesive film layer are co-extruded; Alternatively, the first adhesive film layer and the second adhesive film layer are composited by hot pressing to form the packaging adhesive film.

3. The packaging film according to claim 1, characterized in that: The first adhesive film layer is a POE adhesive film layer, the second adhesive film layer is an EVA adhesive film layer, and the adhesive film layers on both sides are POE adhesive film layers.

4. The packaging film according to claim 3, characterized in that: The width of the POE film layer is 5 to 30 mm; the width of the EVA film layer is 162 to 230 mm.

5. The packaging film according to claim 4, characterized in that: The width of the POE film layers on both sides is 5 to 30 mm, and the width of the POE film layer in the middle is 5 to 15 mm.

6. The packaging film according to claim 4, characterized in that: The width of the EVA film layer is 182±20 mm; or the width of the EVA film layer is 210±20 mm.

7. The packaging film according to claim 3, characterized in that: The crosslinking degree of the POE film layer is 15-45%.

8. A method for preparing a packaging adhesive film according to any one of claims 3 to 7, characterized in that: The preparation method comprises: Prepare POE production raw materials, and then input the POE production raw materials into the second raw material pipeline under a vacuum environment; Prepare EVA production raw materials, and then input the EVA production raw materials into a first raw material pipeline under a vacuum environment; wherein the first raw material pipeline and the second raw material pipeline are independent pipelines; The first raw material pipeline and the second raw material pipeline respectively feed materials to the extruder feed bin, and cast extrusion is performed to obtain the packaging film; Or, the preparation method comprises: POE production raw materials are configured, and then the POE production raw materials are vacuum-transported to the extruder feed bin, and cast extrusion molding is performed to obtain the POE film layer; EVA raw materials are prepared, and then the EVA raw materials are vacuum-transported to a feed bin of an extruder, and cast extrusion molding is performed to obtain the EVA film layer; The POE adhesive film layer and the EVA adhesive film layer are composited by hot pressing to form the encapsulation adhesive film.

9. The preparation method according to claim 8, characterized in that: Also includes: The POE film layer of the packaging film is subjected to electron beam irradiation, the irradiation amount is 15 kGy to 130 kGy, and the irradiation amount is slowly and cumulatively increased until the cross-linking degree of the POE film layer reaches 15% to 45%.

10. A photovoltaic module, characterized in that: The invention comprises the encapsulation adhesive film according to any one of claims 1 to 7, or the encapsulation adhesive film obtained by the preparation method according to any one of claims 8 to 9.

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