Low temperature cross-linked encapsulant, method of making and photovoltaic module

Abstract

The application provides a low-temperature cross-linked adhesive film, a preparation method thereof and a photovoltaic module, and relates to the technical field of photovoltaic module packaging materials. The adhesive film comprises a melting layer, a separation layer and a cross-linking layer which are sequentially stacked. The cross-linking layer of the low-temperature cross-linked adhesive film provided by the application forms a stable network through controlled cross-linking during the lamination process. The microcapsules in the separation layer release active ingredients at a specific temperature to trigger the cross-linking reaction, and at the same time, block the diffusion of the cross-linking agent to the melting layer. The three-dimensional network structure formed by the cross-linking layer provides durable mechanical support, the separation layer ensures precise control of the cross-linking reaction, and the melting layer realizes low-temperature interface sealing. The three work together to effectively solve the contradiction between the processing temperature and the use performance in the conventional technology.

Description

Technical Field

[0001] This application relates to the field of photovoltaic module encapsulation materials technology, and in particular to a low-temperature crosslinking film, its preparation method, and a photovoltaic module. Background Technology

[0002] Energy consumption in photovoltaic module production is becoming increasingly prominent, with the lamination process accounting for 20-30% of the total energy consumption. The main reason for this is that traditional lamination processes require high operating temperatures and long lamination times.

[0003] While existing technologies include methods to lower the crosslinking temperature to 135℃ by increasing the proportion of crosslinking agent in the encapsulant film, the crosslinking system and crosslinking trigger temperature remain essentially unchanged. This necessitates extending the lamination time while lowering the temperature, resulting in limited actual energy-saving effects. Another approach, using non-crosslinked encapsulant films, can reduce the lamination temperature to 100-125℃, but its mechanical strength is significantly insufficient due to the lack of a crosslinked network structure. In practical applications, photovoltaic modules typically require installation at a certain tilt angle, subjecting the encapsulant film to long-term shear stress. Coupled with the high operating temperature of the modules, this easily leads to film displacement and module deformation, severely impacting the sealing performance of the solar cells. Furthermore, the low melting point of non-crosslinked encapsulant films makes them highly susceptible to melting and bulging when hot spots occur in the module, causing appearance defects and sealing failure.

[0004] These technical defects severely limit the reliability and lifespan of photovoltaic modules. To address these issues, existing technologies urgently need improvement. Summary of the Invention

[0005] The purpose of this application is to provide a low-temperature crosslinking adhesive film, its preparation method, and a photovoltaic module to solve the above-mentioned problems.

[0006] To achieve the above objectives, this application adopts the following technical solution: This application provides a low-temperature crosslinking adhesive film, comprising a melt layer, a release layer, and a crosslinking layer stacked sequentially; The molten layer, calculated based on 100% of its total raw material mass, comprises: 70-86.8% first POE, 13-18% polyolefin elastomer, 0.1-1% nano boron nitride, and 0.1-1% hydrogenated petroleum resin; The isolation layer, calculated based on 100% of its total raw material mass, comprises: 80-89.8% second POE, 8.6-14.5% EVA-g-MAH-based microcapsules, 1.5-2% blocked silane, and 0.1-0.8% anti-migration agent; The cross-linked layer, calculated based on 100% of the total mass of its raw materials, includes: 97-98.9% third POE, 0.5-1.5% DCP, 0.5-1.5% cross-linking agent, and 0.1-1.5% carbon nanotubes.

[0007] Optionally, the thickness of the adhesive film is 0.4-0.6 mm.

[0008] Optionally, the thickness ratio of the crosslinking layer, the isolation layer, and the molten layer is 15-30:15-20:50-70.

[0009] Optionally, the first POE, the second POE, and the third POE each independently comprise an ethylene-α-olefin copolymer; The ethylene-α-olefin copolymer includes 1-octene and 1-butene.

[0010] Optionally, the melt flow index of the first POE is not less than 35 g / 10 min.

[0011] Optionally, the polyolefin elastomer includes at least one of ethylene-octene copolymer, ethylene-butene copolymer, and ethylene-hexene copolymer.

[0012] Optionally, the particle size of the nano-boron nitride is 20-100 nm.

[0013] Optionally, based on the total mass of the raw materials in the isolation layer being 100%, the raw materials of the EVA-g-MAH-based microcapsules include: 8-12% microcapsules, 0.5-1.5% EVA-g-MAH-encapsulated peroxide, and 0.1-1% organic zinc. The microcapsules include at least one of polymethyl methacrylate microcapsules, melamine resin microcapsules, and polyurethane microcapsules; The peroxide includes DTBPH; The organic zinc includes diethyl zinc; Optionally, the blocked silane comprises VTMS protected by ketimine, and the unblocking temperature of the blocked silane is 110°C.

[0014] Optionally, the anti-migration agent comprises hydrogenated castor oil.

[0015] Optionally, the crosslinking agent includes TMPTA.

[0016] Optionally, the carbon nanotubes have a diameter of 5-50 nm and a length of 1-10 μm.

[0017] Secondly, this application provides a method for preparing a low-temperature crosslinked adhesive film, comprising: The raw materials for the crosslinking layer, the isolation layer, and the molten layer are pretreated. The crosslinking layer, the isolation layer, and the melt layer are sequentially formed using a three-layer co-extrusion technology. The low-temperature cross-linked film is obtained after post-processing.

[0018] Optionally, the first POE, the second POE, the third POE, and the EVA-g-MAH are dried; The drying temperature is 80-90℃, the time is 4-6 hours, and the final moisture content is not higher than 300ppm.

[0019] Optionally, the nano-boron nitride and the carbon nanotubes are mixed with POE and then dispersed; the dispersion speed is 1000-3000 rpm.

[0020] Optionally, the microcapsules and the hydrogenated castor oil are mixed at 20-50 rpm, at a mixing temperature of 10-30°C, and for a mixing time of 5-10 min.

[0021] Optionally, the three-layer co-extrusion technology satisfies: Melted layer: The raw material for the molten layer is extruded using a first extruder. The temperature of the feeding section is 100-120℃, the temperature of the compression section is 150-170℃, and the temperature of the die head is 180-200℃.

[0022] Separation layer: The raw material for the separation layer is extruded using a second extruder; The temperature of the feeding section is 80-90℃, the temperature of the compression section is 100-110℃, and the temperature of the die head is 110-115℃.

[0023] Crosslinked layer: The raw material for the crosslinked layer is extruded using a third extruder; The temperature of the feeding section is 90-100℃, the temperature of the compression section is 110-130℃, and the temperature of the co-extrusion die head is 130-140℃. The co-extrusion die head uses a zoned temperature control method: Upper flow channel: 175-185℃; Middle flow channel: 110-115℃; Lower flow channel: 130-135℃; Confluence zone outlet: 140-150℃.

[0024] Optionally, the post-processing includes sequential pressing and cold pressing.

[0025] Optionally, the pressing is performed using precision calendering rolls under the following conditions: pressing temperature 120-140°C, pressure range 0.5-1.5 MPa.

[0026] Optionally, the cold pressing is performed using a cooling roller with a surface temperature of 20-30°C.

[0027] This application also provides a photovoltaic module, including solar cells and the encapsulating film; The adhesive film includes, in the direction away from the battery cell, the molten layer, the insulating layer, and the crosslinking layer arranged sequentially.

[0028] Compared with the prior art, the beneficial effects of this application include: The low-temperature crosslinking film provided in this application forms a stable network through controlled crosslinking during lamination. Microcapsules in the separator layer release active ingredients at a specific temperature to trigger the crosslinking reaction, while simultaneously preventing the crosslinking agent from diffusing into the molten layer. The molten layer melts and flows at a lower temperature, filling the microscopic voids between the solar cell and the glass. The three-layer structure achieves phased functionality through temperature gradient control: the molten layer flows preferentially to complete interface filling, and the separator layer subsequently releases the crosslinking agent to solidify the crosslinking layer, ultimately forming a composite film with both low-temperature processability and high-temperature stability. The molten layer fills voids in the first melting chamber, ensuring no air bubbles within the module. The separator layer ensures the initiation point of the crosslinking reaction, effectively isolating peroxides, silanes, and the crosslinking layer. Final crosslinking can be completed rapidly in the second crosslinking chamber. This application maintains the integrity of the film structure while reducing lamination temperature, reducing lamination process energy consumption and preventing film failure due to shear forces or high-temperature environments after module installation. The three-dimensional network structure formed by the cross-linking layer provides durable mechanical support, the isolation layer ensures precise control of the cross-linking reaction, and the molten layer achieves low-temperature interface sealing. The synergistic effect of these three elements effectively solves the contradiction between processing temperature and performance in traditional technologies. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0030] Figure 1 The finished film obtained in Example 1. Detailed Implementation

[0031] As used in this article: "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0032] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0033] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0034] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0035] "Parts by mass" refers to the basic unit of measurement that expresses the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2.689g. If we say that component A has "a" parts by mass and component B has "b" parts by mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (where K is any number representing a multiplier). It is important to understand that, unlike parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0036] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0037] To better explain the technical solution provided in this application, a general explanation of the technical solution provided in this application will be given before proceeding with specific implementation methods.

[0038] In existing technologies, the lamination process in photovoltaic module production consumes a lot of energy, mainly due to the high temperature and long processing time. Although traditional cross-linked films can reduce the lamination temperature by adjusting the cross-linking agent ratio, the cross-linking trigger temperature remains unchanged, requiring an extension of the lamination time. Non-cross-linked films can reduce the lamination temperature, but the lack of a cross-linked network structure results in insufficient mechanical strength. After module installation, they are susceptible to displacement due to shear forces and are prone to melting and failure under high temperature conditions.

[0039] To address the aforementioned issues, a solution is needed that can both reduce lamination temperature and maintain the stability of the film structure. Analysis of the advantages and disadvantages of cross-linked and non-cross-linked systems reveals that a layered structure can meet both low-temperature processing and high-temperature application requirements. The cross-linked layer provides mechanical support, the isolation layer blocks component migration, and the molten layer enables low-temperature filling; the synergistic effect of these three elements overcomes the limitations of single-material performance.

[0040] Therefore, this application provides a low-temperature crosslinking adhesive film, comprising a melt layer, a release layer and a crosslinking layer stacked sequentially; The molten layer, calculated based on 100% of its total raw material mass, comprises: 70-86.8% first POE, 13-18% polyolefin elastomer, 0.1-1% nano boron nitride, and 0.1-1% hydrogenated petroleum resin.

[0041] Optionally, the amount of the first POE can be 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 86.8%, or any value between 70% and 86.8%; the amount of the polyolefin elastomer can be 13%, 14%, 15%, 16%, 17%, 18%, or any value between 13% and 18%; the amount of nano boron carbide can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or any value between 0.1% and 1%; the amount of hydrogenated petroleum resin can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, or any value between 0.1% and 1%.

[0042] The isolation layer, calculated based on 100% of its total raw material mass, comprises: 80-89.8% second POE, 8.6-14.5% EVA-g-MAH-based microcapsules, 1.5-2% blocked silane, and 0.1-0.8% anti-migration agent.

[0043] Optionally, the amount of the second POE can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 89.8%, or any value between 80% and 89.8%; the amount of EVA-g-MAH-based microcapsules can be 8.6%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, or any value between 8.6% and 14.5%; the amount of blocked silane can be 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, or any value between 1.5% and 2%; and the amount of anti-migration agent can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, or any value between 0.1% and 0.8%.

[0044] The cross-linked layer, calculated based on 100% of the total mass of its raw materials, includes: 97-98.9% POE (third POE), 0.5-1.5% DCP (diisopropylbenzene peroxide), 0.5-1.5% cross-linking agent, and 0.1-1.5% carbon nanotubes.

[0045] Optionally, the amount of the third POE can be 97%, 97.5%, 98%, 98.5%, 98.9%, or any value between 97% and 98.9%; the amount of DCP can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, or any value between 0.5% and 1.5%; the amount of crosslinking agent can be 0.5%, 0.6%, 0. 7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, or any value between 0.5% and 1.5%; the amount of carbon nanotubes can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, or any value between 0.1% and 1.5%.

[0046] In one optional embodiment, the thickness of the adhesive film is 0.4-0.6 mm.

[0047] Optionally, the thickness of the adhesive film can be 0.4 mm, 0.41 mm, 0.42 mm, 0.43 mm, 0.44 mm, 0.45 mm, 0.46 mm, 0.47 mm, 0.48 mm, 0.49 mm, 0.5 mm, 0.51 mm, 0.52 mm, 0.53 mm, 0.54 mm, 0.55 mm, 0.56 mm, 0.57 mm, 0.58 mm, 0.59 mm, 0.6 mm, or any value between 0.4 and 0.6 mm.

[0048] In one optional embodiment, the thickness ratio of the molten layer, the isolation layer, and the crosslinking layer is 50-70:15-20:15-30.

[0049] Optionally, the thickness ratio of the crosslinking layer, the isolation layer, and the molten layer can be 30:20:50, 20:20:60, 15:15:75, or any value between 15-30:15-20:50-70.

[0050] In one optional implementation, the first POE, the second POE, and the third POE each independently comprise an ethylene-α-olefin copolymer; The ethylene-α-olefin copolymer includes 1-octene and 1-butene.

[0051] In an optional embodiment, the melt index of the first POE is not less than 35 g / 10 min, and the relative molecular weight is 20,000-40,000.

[0052] In an optional embodiment, the polyolefin elastomer includes at least one of ethylene-octene copolymers (such as Dow Engage™ series), ethylene-butene copolymers (such as Mitsui Chemicals Tafmer™ series), and ethylene-hexene copolymers (such as ExxonMobil Exact™ series).

[0053] In one optional embodiment, the boron nanoparticles have a particle size of 20-100 nm.

[0054] In an optional embodiment, the raw materials of the EVA-g-MAH-based microcapsules are calculated based on the total mass of the raw materials of the isolation layer as 100%, and the raw materials include: 8-12% microcapsules, 0.5-1.5% EVA-g-MAH-encapsulated peroxide, and 0.1-1% organic zinc.

[0055] The microcapsules include at least one of polymethyl methacrylate (PMMA) microcapsules, melamine resin (melamine-formaldehyde resin) microcapsules, and polyurethane (PU) microcapsules.

[0056] The peroxide includes di-tert-butyl hydroperoxide (DTBPH).

[0057] The organic zinc includes diethyl zinc.

[0058] EVA-g-MAH is a chemically modified product of ethylene-vinyl acetate copolymer (EVA) grafted with maleic anhydride. EVA itself has good film-forming properties and mechanical properties. Through emulsification, phase separation and other techniques, it can form microcapsule particles encapsulating peroxide (DTBPH) and catalyst (organozinc). Polyethylene (PE) homopolymer has high regularity and crystallinity, and its melting point is usually above 120℃. The introduction of VA monomer, with its large side group acetate group (-OCOCH3), disrupts the regularity of the polyethylene molecular chain, hindering the close packing and crystallization of chain segments. The higher the VA content, the greater the disruptive effect on crystallization, the lower the crystallinity of the material, and the significantly lower the melting point, while increasing flexibility, transparency and impact resistance. In the technical solution of this application, the VA content is relatively low (15-25%), and the melting point of EVA-g-MAH is precisely designed to be 115℃. This means that in the first lamination chamber at 100°C, the wall material remains solid and possesses high mechanical strength, acting like a robust dam to firmly lock in the highly reactive substances, preventing their migration and premature reaction. When lamination enters the second chamber, the temperature rises to 125°C, exceeding the wall material's melting point of 115°C. The capsule shell rapidly melts and disintegrates, instantly releasing the encapsulated peroxides and catalysts, thus precisely triggering the cross-linking reaction. The grafted MAH polar groups may also enhance the interaction between the wall material and the core material, as well as the surrounding materials.

[0059] In an optional embodiment, the blocked silane comprises ketimine-protected vinyltrimethoxysilane (VTMS), and the blocked silane has an unblocking temperature of 110°C.

[0060] Vinyltrimethoxysilane (CH2=CH-Si(OCH3)3) is one such example. The methoxy group (-OCH3) is an active group that readily reacts with water to form silanol (-Si-OH). This silanol then forms a strong Si-O-Si bond with the hydroxyl groups on the glass surface. Ketoimines are compounds formed by the reaction of ketones (such as methyl isobutyl ketone) and amines (such as hexylamine). The nitrogen atom in the ketimine molecule has a lone pair of electrons, which attacks the silicon atom in the silane molecule, temporarily replacing one methoxy group and forming a stable, larger, inactive "closed silane" adduct. This reaction is reversible. When the temperature rises above the unsealing temperature of 110°C, the equilibrium of this reversible reaction is disrupted. The ketimine protecting group detaches from the silane, decomposing back into the original ketone and amine, which then volatilize, releasing the fully active vinyltrimethoxysilane. This "delayed release" mechanism ensures that the silane does not react or migrate during the low-temperature melting stage. Only during the high-temperature crosslinking stage is the active silane released, which immediately undergoes a coupling reaction with the glass surface, greatly enhancing the adhesion strength between the adhesive film and the glass. At the same time, its vinyl group (CH2=CH-) can also participate in the crosslinking network of POE.

[0061] In an optional embodiment, the anti-migration agent comprises hydrogenated castor oil.

[0062] In an optional embodiment, the crosslinking agent comprises trimethylolpropane triacrylate (TMPTA).

[0063] In one optional embodiment, the carbon nanotubes have a diameter of 5-50 nm and a length of 1-10 μm.

[0064] Optionally, the diameter of the carbon nanotube can be 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, or 50nm, or any value between 5 and 50nm; the length of the carbon nanotube can be 123μm, 4μm, or 5μm, or any value between 1 and 5μm.

[0065] This application also provides a method for preparing a low-temperature crosslinked adhesive film, comprising: The raw materials for the crosslinking layer, the isolation layer, and the molten layer are pretreated. The crosslinking layer, the isolation layer, and the melt layer are sequentially formed using a three-layer co-extrusion technology. The low-temperature cross-linked film is obtained after post-processing.

[0066] In an optional embodiment, the first POE, the second POE, the third POE, and EVA-g-MAH are dried; The drying temperature is 80-90℃, the time is 4-6 hours, and the final moisture content is not higher than 300ppm.

[0067] Optionally, the drying temperature can be 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, or any value between 80℃ and 90℃; the drying time can be 4h, 5h, 6h, or any value between 4h and 6h; the final moisture content can be 100ppm, 200ppm, 300ppm, or any value not less than 300ppm.

[0068] In an optional embodiment, the boron nitride nanoparticles and the carbon nanotubes are mixed with POE and then dispersed; the dispersion speed is 1000-3000 rpm.

[0069] Optionally, the rotation speed at which the nano-boron nitride and the carbon nanotubes are dispersed after being mixed with POE can be 1000 rpm, 2000 rpm, 3000 rpm, or any value between 1000 and 3000 rpm.

[0070] In an optional embodiment, the microcapsules and the hydrogenated castor oil are mixed at 20-50 rpm, at a mixing temperature of 10-30°C, and for 5-10 minutes.

[0071] Optionally, the mixing speed of the microcapsules and hydrogenated castor oil can be 20 rpm, 30 rpm, 40 rpm, 50 rpm, or any value between 20 and 50 rpm; the mixing temperature can be 10℃, 20℃, 30℃, or any value between 10 and 30℃; and the mixing time can be 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, or any value between 5 and 10 min.

[0072] In an optional implementation, the melt layer of the three-layer co-extrusion technology is: the raw material of the melt layer is extruded using a first extruder. The temperature of the feeding section is 100-120℃, the temperature of the compression section is 150-170℃, and the temperature of the die head is 180-200℃.

[0073] Optionally, in the first extruder, the temperature of the feeding section can be 100℃, 101℃, 102℃, 103℃, 104℃, 105℃, 106℃, 107℃, 108℃, 109℃, 110℃, 111℃, 112℃, 113℃, 114℃, 115℃, 116℃, 117℃, 118℃, 119℃, 120℃, or any value between 100℃ and 120℃; the temperature of the compression section can be 150℃, 151℃, 152℃, 153℃, 154℃, 155℃, 156℃, 157℃, 158℃, 159℃, 160℃, 1... The temperatures can be 61℃, 162℃, 163℃, 164℃, 165℃, 166℃, 167℃, 168℃, 169℃, 170℃, or any value between 150℃ and 170℃; the temperature of the die head can be 180℃, 181℃, 182℃, 183℃, 184℃, 185℃, 186℃, 187℃, 188℃, 189℃, 190℃, 191℃, 192℃, 193℃, 194℃, 195℃, 196℃, 197℃, 198℃, 199℃, 200℃, or any value between 180℃ and 200℃.

[0074] In an optional implementation, the isolation layer of the three-layer co-extrusion technology is formed by extruding the raw material of the isolation layer using a second extruder; The temperature of the feeding section is 80-90℃, the temperature of the compression section is 100-110℃, and the temperature of the die head is 110-115℃.

[0075] Optionally, the temperature of the feeding section of the second extruder can be 80℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃, 89℃, 90℃, or any value between 80℃ and 90℃; the temperature of the compression section can be 100℃, 101℃, 102℃, 103℃, 104℃, 105℃, 106℃, 107℃, 108℃, 109℃, 110℃, or any value between 100℃ and 110℃; the die head temperature can be 110℃, 111℃, 112℃, 113℃, 114℃, 115℃, or any value between 110℃ and 115℃.

[0076] In an optional embodiment, the crosslinked layer of the three-layer co-extrusion technology is formed by extruding the raw material of the crosslinked layer using a third extruder; The temperature of the feeding section is 90-100℃, the temperature of the compression section is 110-130℃, and the temperature of the co-extrusion die is 130-140℃.

[0077] Optionally, in the third extruder, the temperature of the feeding section can be 90℃, 91℃, 92℃, 93℃, 94℃, 95℃, 96℃, 97℃, 98℃, 99℃, 100℃, or any value between 90℃ and 100℃; the temperature of the compression section can be 110℃, 115℃, 120℃, 125℃, 130℃, or any value between 110℃ and 130℃; the temperature of the co-extrusion die can be 130℃, 131℃, 132℃, 133℃, 134℃, 135℃, 136℃, 137℃, 138℃, 139℃, 140℃, or any value between 130℃ and 140℃.

[0078] The co-extrusion die head uses a zoned temperature control method: Upper flow channel: 175-185℃; Middle flow channel: 110-115℃; Lower flow channel: 130-135℃; Confluence zone outlet: 140-150℃.

[0079] Optional, zoned temperature control. The temperature of the upper flow channel can be 175℃, 176℃, 177℃, 178℃, 179℃, 180℃, 181℃, 182℃, 183℃, 184℃, 185℃, or any value between 175℃ and 185℃; the temperature of the middle flow channel can be 110℃, 111℃, 112℃, 113℃, 114℃, 115℃, or any value between 110℃ and 115℃. The temperature of the lower flow channel can be 130℃, 131℃, 132℃, 133℃, 134℃, 135℃, or any value between 130℃ and 135℃; the temperature of the confluence zone outlet can be 140℃, 141℃, 142℃, 143℃, 144℃, 145℃, 146℃, 147℃, 148℃, 149℃, 150℃, or any value between 140℃ and 150℃.

[0080] In one alternative implementation, the post-processing includes sequential pressing and cold pressing.

[0081] In an alternative embodiment, the pressing is performed using precision calendering rolls under the following conditions: pressing temperature 120-140°C and pressure range 0.5-1.5 MPa.

[0082] Optionally, the pressing temperature can be 120℃, 125℃, 130℃, 136℃, 140℃, or any value between 120℃ and 140℃; the pressure range can be 0.5MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, 0.9 MPa, 1 MPa, 1.1MPa, 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, or any value between 0.5 and 1.5 MPa.

[0083] In an alternative embodiment, the cold pressing is performed using a cooling roller with a surface temperature of 20-30°C.

[0084] Optionally, the surface temperature of the cooling roller can be 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, or any value between 20℃ and 30℃.

[0085] This application also provides a photovoltaic module, including solar cells and the encapsulating film; The adhesive film includes, in the direction away from the battery cell, the molten layer, the insulating layer, and the crosslinking layer arranged sequentially.

[0086] Photovoltaic modules can be single-glass modules, double-glass modules, or lightweight modules.

[0087] A single-glass module consists of the following components stacked in sequence: glass, encapsulant film, solar cells, encapsulant film, and backsheet.

[0088] A double-glass module consists of layers stacked sequentially: glass, encapsulant film, solar cells, encapsulant film, and glass.

[0089] Solar cell materials include crystalline silicon and perovskite.

[0090] After the components are laid out according to the above structure, they are laminated in a laminator. The laminator is set to 100℃ for 5 minutes in one chamber and 125℃ for 5 minutes in the crosslinking chamber. The final crosslinking degree of the adhesive film is 80%, and the bonding strength is 92 N / cm.

[0091] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0092] The POE material used in the examples and comparative examples was a copolymer of ethylene and 1-octene.

[0093] Example 1 This embodiment provides a low-temperature crosslinking adhesive film: The adhesive film consists of a melt layer, a release layer, and a crosslinking layer stacked sequentially. The thickness of the adhesive film is 0.6 mm, and the thickness ratio of the melt layer, release layer, and crosslinking layer is 15:15:70.

[0094] The melt layer, calculated with a total raw material mass of 100, includes: 85% POE, 14% ethylene-octene copolymer (purchased from Dow Engage™ series), 0.5% nano boron nitride with a particle size of 20nm, and hydrogenated petroleum resin (ExxonMobil, brand Escorez 5600, number average molecular weight (Mn) of approximately 2000-5000 g / mol). The melt index of the POE material in the melt layer raw material is not higher than 35g / 10min.

[0095] The isolation layer, calculated based on 100% of its total raw material mass, includes: POE 85%, EVA-g-MAH-based microcapsules 13.5%, ketimine-protected VTMS (purchased from Evonik Degussa, brand name Dynasylan 1146) 1%, and hydrogenated castor oil (purchased from Ito Sei, Japan, brand name Caster S) 0.5%. Specifically, based on 100% of the total raw material mass of the isolation layer, the EVA-g-MAH-based microcapsules include: polymethyl methacrylate (PMMA) microcapsules (purchased from BASF, Germany, brand name Joncrip 711) 12%, DTBPH (Arkema, France, brand name Luperox 231) 1%, and diethylzinc 0.5%.

[0096] The cross-linked layer, calculated based on the total mass of its raw materials (100%), includes: 98% POE, 1% DCP (purchased from Pergan, Germany, brand name Perkadox BC-FF), 1% TMPTA (purchased from Allnex, Belgium, brand name Ebecryl 110), and 0.2% carbon nanotubes with a diameter of 30 nm and a length of 5 nm.

[0097] This embodiment also provides a method for preparing the low-temperature crosslinked adhesive film, the specific steps of which are as follows: 1.1 Raw material processing: Drying: To prevent hydrolysis and bubbles, the POE and EVA-g-MAH substrates are dried at 85°C for 5 hours, with a moisture content of 100ppm.

[0098] Nanomaterial dispersion: Nano-boron nitride and carbon nanotubes need to be pre-prepared with a small amount of matrix resin in a high-speed mixer (2000 rpm) or a twin-screw extruder (side feed) to prepare high-concentration masterbatch (15% content).

[0099] Microcapsule protection: Microcapsules and hydrogenated castor oil are mixed at room temperature for a short time (20°C, 7 min) in a low-speed mixer (35 rpm) to prevent capsule rupture.

[0100] 1.2 Three-layer co-extrusion Equipment: Three independent single-screw extruders and co-extrusion dies with layered flow channel design.

[0101] First extruder (molten layer): Processing of POE, polyolefin elastomers, nano boron nitride masterbatch, and hydrogenated petroleum resins.

[0102] The temperature of the feeding section is 110℃; the temperature of the compression section is 160℃; and the temperature of the die head is 190℃.

[0103] Second extruder (isolation layer): Processing of POE, EVA-g-MAH microcapsule masterbatch, blocked silane, and hydrogenated castor oil.

[0104] The temperature of the feeding section is 85℃; the temperature of the compression section is 105℃; and the temperature of the die head is 112℃.

[0105] Third extruder (crosslinked layer): Processing of POE, dicumyl peroxide (DCP), TMPTA, and carbon nanotube masterbatch.

[0106] The temperature of the feeding section is 95℃; the temperature of the compression section is 115℃; and the temperature of the die head is 135℃. The co-extrusion die head adopts a zoned temperature control method: The temperature in the upper flow channel is 180℃; the temperature in the middle flow channel is 113℃; the temperature in the lower flow channel is 130℃; and the temperature at the outlet of the confluence zone is 140℃.

[0107] 1.3 Post-processing The total thickness and layer thickness ratio are controlled by precision calendering rollers to 0.6 mm. The film then immediately enters a cooling roller with a surface temperature of 25°C, which rapidly cools the film to below 50°C, freezing interlayer molecular diffusion and preventing component migration and pre-crosslinking.

[0108] The finished adhesive film obtained is as follows Figure 1 As shown.

[0109] Example 2 This embodiment provides a low-temperature crosslinking adhesive film: The adhesive film consists of a melt layer, a release layer, and a crosslinking layer stacked sequentially. The thickness of the adhesive film is 0.6 mm, and the thickness ratio of the melt layer, release layer, and crosslinking layer is 20:20:60.

[0110] The molten layer, calculated with a total raw material mass of 100, includes: 85% POE, 14% ethylene-octene copolymer, 0.5% nano boron nitride with a particle size of 20nm, and hydrogenated petroleum resin.

[0111] The isolation layer, calculated based on 100% of its total raw material mass, includes: 85% POE, 13.5% EVA-g-MAH-based microcapsules, 1% ketimine-protected VTMS, and 0.5% hydrogenated castor oil. Specifically, based on 100% of the total raw material mass of the isolation layer, the EVA-g-MAH-based microcapsules consist of 12% polymethyl methacrylate (PMMA) microcapsules, 1% DTBPH, and 0.5% diethylzinc.

[0112] The cross-linked layer, calculated based on the total mass of its raw materials (100%), includes: 98% POE, 1% DCP, 1% TMPTA, and 0.2% carbon nanotubes with a diameter of 30 nm and a length of 5 nm.

[0113] This embodiment also provides a method for preparing the low-temperature crosslinked adhesive film, the specific steps of which are as follows: 1.1 Raw material processing: Drying: To prevent hydrolysis and bubbles, the POE and EVA-g-MAH substrates are dried at 85°C for 5 hours, with a moisture content of 100ppm.

[0114] Nanomaterial dispersion: Nano-boron nitride and carbon nanotubes need to be pre-prepared with a small amount of matrix resin in a high-speed mixer (2000 rpm) or a twin-screw extruder (side feed) to prepare high-concentration masterbatch (15% content).

[0115] Microcapsule protection: Microcapsules and hydrogenated castor oil are mixed at room temperature for a short time (20°C, 7 min) in a low-speed mixer (35 rpm) to prevent capsule rupture.

[0116] 1.2 Three-layer co-extrusion Equipment: Three independent single-screw extruders and co-extrusion dies with layered flow channel design.

[0117] First extruder (molten layer): Processing of POE, polyolefin elastomers, nano boron nitride masterbatch, and hydrogenated petroleum resins.

[0118] The temperature of the feeding section is 110℃; the temperature of the compression section is 160℃; and the temperature of the die head is 190℃.

[0119] Second extruder (isolation layer): Processing of POE, EVA-g-MAH microcapsule masterbatch, blocked silane, and hydrogenated castor oil.

[0120] The temperature of the feeding section is 85℃; the temperature of the compression section is 105℃; and the temperature of the die head is 112℃.

[0121] Third extruder (crosslinked layer): Processing of POE, dicumyl peroxide (DCP), TMPTA, and carbon nanotube masterbatch.

[0122] The temperature of the feeding section is 95℃; the temperature of the compression section is 115℃; and the temperature of the die head is 135℃. The co-extrusion die head adopts a zoned temperature control method: The temperature in the upper flow channel is 180℃; the temperature in the middle flow channel is 113℃; the temperature in the lower flow channel is 130℃; and the temperature at the outlet of the confluence zone is 140℃.

[0123] 1.3 Post-processing The total thickness and layer thickness ratio are controlled by precision calendering rollers to 0.6 mm. The film then immediately enters a cooling roller with a surface temperature of 25°C, which rapidly cools the film to below 50°C, freezing interlayer molecular diffusion and preventing component migration and pre-crosslinking.

[0124] Example 3 This embodiment provides a low-temperature crosslinking adhesive film: The adhesive film consists of a melt layer, a release layer, and a crosslinking layer stacked sequentially. The thickness of the adhesive film is 0.6 mm, and the thickness ratio of the melt layer, release layer, and crosslinking layer is 20:20:60.

[0125] The molten layer, calculated with a total raw material mass of 100, includes: 85% POE, 14% ethylene-octene copolymer, 0.5% nano boron nitride with a particle size of 20nm, and hydrogenated petroleum resin.

[0126] The isolation layer, calculated based on 100% of its total raw material mass, includes: 85% POE, 13.5% EVA-g-MAH-based microcapsules, 1% ketimine-protected VTMS, and 0.5% hydrogenated castor oil. Specifically, based on 100% of the total raw material mass of the isolation layer, the EVA-g-MAH-based microcapsules contain: 12% microcapsules, 1% DTBPH, and 0.5% diethylzinc.

[0127] The cross-linked layer, calculated based on the total mass of its raw materials (100%), includes: 98% POE, 1% DCP, 1% TMPTA, and 0.2% carbon nanotubes with a diameter of 30 nm and a length of 5 nm.

[0128] This embodiment also provides a method for preparing the low-temperature crosslinked adhesive film, the specific steps of which are as follows: 1.1 Raw material processing: Drying: To prevent hydrolysis and bubbles, the POE and EVA-g-MAH substrates are dried at 85°C for 5 hours, with a moisture content of 100ppm.

[0129] Nanomaterial dispersion: Nano-boron nitride and carbon nanotubes need to be pre-prepared with a small amount of matrix resin in a high-speed mixer (2000 rpm) or a twin-screw extruder (side feed) to prepare high-concentration masterbatch (15% content).

[0130] Microcapsule protection: Microcapsules and hydrogenated castor oil are mixed at room temperature for a short time (20°C, 7 min) in a low-speed mixer (35 rpm) to prevent capsule rupture.

[0131] 1.2 Three-layer co-extrusion Equipment: Three independent single-screw extruders and co-extrusion dies with layered flow channel design.

[0132] First extruder (molten layer): Processing of POE, polyolefin elastomers, nano boron nitride masterbatch, and hydrogenated petroleum resins.

[0133] The temperature of the feeding section is 85℃; the temperature of the compression section is 105℃; and the temperature of the die head is 120℃.

[0134] Second extruder (isolation layer): Processing of POE, EVA-g-MAH microcapsule masterbatch, blocked silane, and hydrogenated castor oil.

[0135] The temperature of the feeding section is 85℃; the temperature of the compression section is 105℃; and the temperature of the die head is 112℃.

[0136] Third extruder (crosslinked layer): Processing of POE, dicumyl peroxide (DCP), TMPTA, and carbon nanotube masterbatch.

[0137] The temperature of the feeding section is 95℃; the temperature of the compression section is 115℃; and the temperature of the die head is 135℃. The co-extrusion die head adopts a zoned temperature control method: The temperature in the upper flow channel is 180℃; the temperature in the middle flow channel is 113℃; the temperature in the lower flow channel is 130℃; and the temperature at the outlet of the confluence zone is 140℃.

[0138] 1.3 Post-processing The total thickness and layer thickness ratio are controlled by precision calendering rollers to 0.6 mm. The film then immediately enters a cooling roller with a surface temperature of 25°C, which rapidly cools the film to below 50°C, freezing interlayer molecular diffusion and preventing component migration and pre-crosslinking.

[0139] Comparative Example 1 This comparative example provides a conventional adhesive film: Comparative Example 1 is a conventional photovoltaic module encapsulant film, in which the film matrix is ​​a polyolefin elastomer, a copolymer of ethylene and α-butene, accounting for 97%; the melt index is 2 g / 10 min; the crosslinking agent is tert-butyl peroxide (2-ethylhexyl) carbonate, accounting for 1.5%; the co-crosslinking agent is triallyl isocyanurate, accounting for 1%; and the silane coupling agent is γ-aminopropyltriethoxysilane, accounting for 0.5%.

[0140] Comparative Example 2 This comparative example provides an adhesive film that, compared to Example 1, only has an isolation layer and a crosslinking layer, with a thickness ratio of 20:80.

[0141] Comparative Example 3 This comparative example provides an adhesive film that, compared to Example 1, only has a melt layer and a crosslinking layer, with a thickness ratio of 20:80.

[0142] Comparative Example 4 This comparative example provides an adhesive film that, compared to Example 1, only has a molten layer and an isolation layer, with a thickness ratio of 20:80.

[0143] Comparative Example 5 This comparative example provides a film that differs from Example 1 only in that the VTMS in the isolation layer is not protected by ketimine as a blocked silane, but by a conventional silane.

[0144] Comparative Example 6 This comparative example provides a film that differs from Example 1 only in that the EVA-g-MAH-based microcapsules in the isolation layer encapsulate DTBPH and diethylzinc, instead of directly exposed DTBPH and diethylzinc.

[0145] Comparative Example 7 This comparative example provides a film that differs from Example 1 only in that the melt layer uses a conventional film with a melt index of 2 g / 10 min.

[0146] Comparative Example 8 This comparative example provides a film that differs from Example 1 only in that the release layer is a conventional film, the melt index is 2 g / 10 min, the crosslinking agent is tert-butyl peroxide (2-ethylhexyl) carbonate, and the co-crosslinking agent is triallyl isocyanurate.

[0147] The properties of the films provided in the examples and comparative examples are shown in Table 1: Table 1 Film Properties

[0148] As shown in Table 1: Regarding film performance: Example 1 (Complete Three-Layer Structure): All properties are well-balanced and excellent. Crosslinking degree 80% (good), bonding strength 92 N / cm (extremely high), air bubble ratio 0.05% (extremely low), mechanical strength 12 MPa (good). This demonstrates the success of the three-layer synergistic effect.

[0149] Comparative Example 2 (without melt layer): It exhibited the highest degree of cross-linking and mechanical strength, but the proportion of air bubbles increased sharply to 8.7%. This is because the lack of a dedicated fast-flowing filler layer prevented effective air removal during lamination. Adhesive strength also decreased.

[0150] Comparative Example 3 (without an isolation layer): The degree of crosslinking, bonding strength, and mechanical strength all decreased, and the proportion of air bubbles was as high as 12.3%. This is because without the protection of the isolation layer, the crosslinking agent of the crosslinking layer decomposes and is consumed in large quantities in the first lamination chamber (100℃), resulting in insufficient crosslinking in the second chamber (125℃). At the same time, premature crosslinking also hinders the flow and degassing of the film.

[0151] Comparative Example 4 (without cross-linking layer): The degree of cross-linking is 0, resulting in a sharp drop in adhesive strength and mechanical strength. This proves that the cross-linking layer is the fundamental guarantee of final performance, and the adhesive film without cross-linking has almost no practical value.

[0152] Regarding the layer thickness ratio: The layer thickness ratio needs to be optimized and balanced. The cross-linked layer, as the main body, must occupy a sufficient proportion (e.g., 70%) to ensure overall performance. Too high or too low a proportion of the other two layers will negatively impact performance.

[0153] Regarding the production process: By controlling the temperature of the intermediate die, the melting and cracking of the microcapsule wall material can be prevented, thus avoiding the premature release of internal peroxides and organic zinc during extrusion and preventing partial cross-linking. This increases the degree of cross-linking and prevents premature curing of the adhesive, which reduces fluidity and consequently lowers the proportion of air bubbles, thus decreasing adhesive strength and mechanical strength. In short, the production process, especially temperature control, is the lifeline for ensuring the activity of functional materials (such as microcapsules). Precise temperature control is a prerequisite for achieving the design intent.

[0154] Regarding functional additives: Example 1 uses closed silane and microcapsules, and its performance in all aspects is superior to that of the comparative example.

[0155] Comparative Example 5 used ordinary silane. While the crosslinking degree and mechanical strength were acceptable, the bonding strength plummeted from 92 N / cm to 51 N / cm, and air bubbles increased. This is because ordinary silane is hydrolyzed and activated during processing, reacting with or being destroyed by POE, thus failing to effectively promote adhesion during lamination.

[0156] Comparative Example 6, using exposed peroxide and organozinc, achieved an even higher degree of crosslinking (85%), but its adhesive strength (63 N / cm) was low, and it had a higher proportion of air bubbles (7.5%). This is because the exposed additives decompose and volatilize in large quantities during extrusion, leading to premature consumption of the crosslinking agent (although the data shows a high degree of crosslinking, this may be due to differences in testing methods or conditions, but it is more likely that residual crosslinking agent still plays a role in the later stages). Furthermore, the volatile components become the source of air bubbles.

[0157] Delayed release technology (microcapsules, blocked compounds) is key to achieving the "low-temperature isolation, high-temperature triggering" function. It protects the active ingredients safely through the processing stage and allows them to function precisely during lamination, thereby simultaneously achieving high cross-linking degree, high adhesion strength, and low bubble rate.

[0158] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0159] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the foregoing claims, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A low-temperature crosslinked adhesive film, characterized in that, It includes a melt layer, a release layer, and a cross-linking layer stacked sequentially; The molten layer, calculated based on 100% of its total raw material mass, comprises: 70-86.8% first POE, 13-18% polyolefin elastomer, 0.1-1% nano boron nitride, and 0.1-1% hydrogenated petroleum resin; The isolation layer, calculated based on 100% of its total raw material mass, comprises: 80-89.8% second POE, 8.6-14.5% EVA-g-MAH-based microcapsules, 1.5-2% blocked silane, and 0.1-0.8% anti-migration agent; The cross-linked layer, calculated based on 100% of the total mass of its raw materials, includes: 97-98.9% POE (third layer), 0.5-1.5% DCP (dual core polymer), 0.5-1.5% cross-linking agent, and 0.1-1.5% carbon nanotubes.

2. The low-temperature crosslinked adhesive film according to claim 1, characterized in that, At least one of the following conditions must be met: a. The thickness of the adhesive film is 0.4-0.6 mm; b. The thickness ratio of the molten layer, the isolation layer, and the crosslinking layer is 15-30:15-20:50-70; c. The first POE, the second POE, and the third POE each independently comprise an ethylene-α-olefin copolymer; The ethylene-α-olefin copolymer includes 1-octene and 1-butene.

3. The low-temperature crosslinked adhesive film according to claim 1, characterized in that, At least one of the following conditions must be met: d. The melt flow index of the first POE is not less than 35 g / 10 min, and the relative molecular weight is 20,000-40,000; e. The polyolefin elastomer comprises at least one of ethylene-octene copolymer, ethylene-butene copolymer, and ethylene-hexene copolymer; f. The particle size of the nano-boron nitride is 20-100 nm.

4. The low-temperature crosslinked adhesive film according to claim 1, characterized in that, At least one of the following conditions must be met: g. Calculated based on the total mass of the raw materials in the isolation layer as 100%, the raw materials of the EVA-g-MAH-based microcapsules include: 8-12% microcapsules, 0.5-1.5% EVA-g-MAH-encapsulated peroxide, and 0.1-1% organic zinc; The microcapsules include at least one of polymethyl methacrylate microcapsules, melamine resin microcapsules, and polyurethane microcapsules; The peroxide includes DTBPH; The organic zinc includes diethyl zinc; h. The blocked silane comprises VTMS protected by ketimine, and the unblocking temperature of the blocked silane is 110°C; i. The anti-migration agent includes hydrogenated castor oil.

5. The low-temperature crosslinked adhesive film according to any one of claims 1-4, characterized in that, At least one of the following conditions must be met: j. The crosslinking agent includes TMPTA; k. The carbon nanotubes have a diameter of 5-50 nm and a length of 1-10 μm.

6. A method for preparing a low-temperature crosslinked adhesive film according to any one of claims 1-5, characterized in that, include: The raw materials for the crosslinking layer, the isolation layer, and the molten layer are pretreated. The crosslinking layer, the isolation layer, and the melt layer are sequentially formed using a three-layer co-extrusion technology. The low-temperature cross-linked film is obtained after post-processing.

7. The method for preparing a low-temperature crosslinked adhesive film according to claim 6, characterized in that, The preprocessing satisfies at least one of the following conditions: A. Dry the first POE, the second POE, the third POE, and EVA-g-MAH; The drying temperature is 80-90℃, the time is 4-6 hours, and the final moisture content is not higher than 300ppm; B. The nano-boron nitride and the carbon nanotubes are respectively mixed with POE and then dispersed; the dispersion speed is 1000-3000 rpm; C. Mix the microcapsules and the hydrogenated castor oil at 20-50 rpm, at a mixing temperature of 10-30°C, for 5-10 minutes.

8. The method for preparing a low-temperature crosslinked adhesive film according to claim 6, characterized in that, The three-layer co-extrusion technology satisfies at least one of the following conditions: D. Melted Layer: The raw material for the molten layer is extruded using a first extruder. The temperature of the feeding section is 100-120℃, the temperature of the compression section is 150-170℃, and the temperature of the die head is 180-200℃. E. Separating layer: The raw material for the separating layer is extruded using a second extruder; The temperature of the feeding section is 80-90℃, the temperature of the compression section is 100-110℃, and the temperature of the die head is 110-115℃. F. Crosslinked layer: The raw material for the crosslinked layer is extruded using a third extruder; The temperature of the feeding section is 90-100℃, the temperature of the compression section is 110-130℃, and the temperature of the co-extrusion die head is 130-140℃. The co-extrusion die head uses a zoned temperature control method: Upper flow channel: 175-185℃; Middle flow channel: 110-115℃; Lower flow channel: 130-135℃; Confluence zone outlet: 140-150℃.

9. The method for preparing a low-temperature crosslinked adhesive film according to any one of claims 6-8, characterized in that, The post-processing includes sequential pressing and cold pressing; and satisfies at least one of the following conditions: G. The pressing is performed using precision calendering rolls under the following conditions: pressing temperature 120-140℃, pressure range 0.5-1.5MPa; H. The cold pressing is performed using a cooling roller with a surface temperature of 20-30°C.

10. A photovoltaic module, characterized in that, Includes battery cells and the adhesive film according to any one of claims 1-5; The adhesive film includes, in the direction away from the battery cell, the molten layer, the insulating layer, and the crosslinking layer arranged sequentially.

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