Composite packaging adhesive film and preparation method and application thereof

Abstract

The invention relates to a composite packaging adhesive film as well as a preparation method and application thereof. The composite packaging adhesive film comprises an upper adhesive film layer, a middle adhesive film layer and a lower adhesive film layer which are sequentially stacked, the cross-linking degree of the middle adhesive film layer is greater than that of the upper adhesive film layer, and the cross-linking degree of the middle adhesive film layer is greater than that of the lower adhesive film layer; the preparation raw materials of the upper adhesive film layer and the lower adhesive film layer respectively and independently comprise coupling agent modified resin master batch A and a polymerization inhibitor; the middle adhesive film layer is prepared from the following raw materials: coupling agent modified resin master batch B and a cross-linking accelerant. The composite packaging adhesive film provided by the invention can realize lamination packaging of a perovskite battery at 105 DEG C or below, and crosslinking can be effectively realized without introducing a peroxide crosslinking agent harmful to perovskite in the crosslinking process of the composite packaging adhesive film.

Description

Technical Field

[0001] This invention relates to the field of adhesive film technology, and in particular to a composite encapsulation film, its preparation method, and its application. Background Technology

[0002] Perovskite solar cells are a type of advanced solar photovoltaic product with high photoelectric conversion efficiency, but stability issues limit their large-scale commercial use. Therefore, the encapsulation of perovskite solar cells has more stringent requirements. However, since perovskite contains organic components such as methylamine and formamidinium, which are easily volatilized at high temperatures, the encapsulation temperature of the encapsulation film material cannot exceed 130°C.

[0003] Commonly used encapsulating films (such as EVA and PVB) typically require lamination operations at temperatures above 150°C, making them unsuitable for perovskite solar cell encapsulation. Existing thermoplastic encapsulating films can achieve encapsulation at 120°C (such as the encapsulating film provided by CN117736656A), but there is still a risk of damaging the perovskite solar cell. However, further lowering the encapsulation temperature would lead to longer encapsulation times and reduced production efficiency due to the high melting point of existing thermoplastic encapsulating films and insufficient resin melting during low-temperature encapsulation.

[0004] In recent years, perovskite solar cells have tended to use cross-linked encapsulating films, which can address the hot spot issue in crystalline silicon modules and reduce encapsulation temperature. However, cross-linked films use peroxides as cross-linking agents. Peroxide cross-linking agents suffer from low cross-linking degrees at relatively low lamination temperatures, and they also generate a large number of free radicals during use, which can damage the perovskite.

[0005] Therefore, how to provide an encapsulation film that can encapsulate perovskite cells at low temperatures without damaging the perovskite has become an urgent problem to be solved. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a composite encapsulating film, its preparation method, and its application. This method enables lamination and encapsulation of perovskite solar cells at temperatures below 105°C, and effectively achieves crosslinking without introducing peroxide crosslinking agents that are harmful to perovskite during the crosslinking process of the composite encapsulating film.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a composite encapsulating film, the composite encapsulating film comprising an upper encapsulating film layer, an intermediate encapsulating film layer and a lower encapsulating film layer stacked sequentially.

[0009] The degree of crosslinking of the intermediate adhesive film layer is greater than that of the upper adhesive film layer, and the degree of crosslinking of the intermediate adhesive film layer is greater than that of the lower adhesive film layer;

[0010] The raw materials for preparing the upper and lower adhesive film layers each independently include coupling agent-modified resin masterbatch A and a polymerization inhibitor;

[0011] The raw materials for preparing the intermediate film layer include coupling agent-modified resin masterbatch B and crosslinking accelerator.

[0012] This invention provides a composite encapsulating film with pre-crosslinking before lamination by designing its structure. This avoids the use of peroxide crosslinking agents, satisfying both the low-temperature lamination requirements of perovskite batteries and the crosslinking needs of crystalline silicon modules. The invention pre-designs upper and lower encapsulating film layers with low crosslinking degrees, ensuring sufficient active groups in both layers to enhance adhesion between the film and the substrate or solar cell. The higher crosslinking degree of the intermediate encapsulating film layer improves the overall mechanical properties and stability of the composite encapsulating film, preventing deformation during lamination. This invention uses coupling agent-modified resin masterbatch as the raw material for the encapsulating film layers. By introducing self-reactive groups, effective crosslinking can be achieved without further addition of peroxide crosslinking agents during the crosslinking process, avoiding damage to perovskite solar cells caused by peroxide crosslinking agents. Furthermore, introducing polymerization inhibitors into the raw materials for the upper and lower encapsulating film layers effectively regulates the degree of crosslinking.

[0013] Preferably, the degree of crosslinking of the adhesive film layer is 0-30%, for example, it can be 0%, 5%, 10%, 15%, 20%, 25% or 30%, etc.

[0014] Preferably, the degree of crosslinking of the intermediate adhesive film layer is 30-90%, for example, it can be 30%, 40%, 50%, 60%, 70%, 80% or 90%, etc.

[0015] Preferably, the degree of crosslinking of the lower adhesive film layer is 0-30%, for example, it can be 0%, 5%, 10%, 15%, 20%, 25% or 30%, etc.

[0016] Preferably, the thickness of the adhesive film layer is 30-150 μm, for example, it can be 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm or 150 μm, etc.

[0017] Preferably, the thickness of the intermediate adhesive film layer is 150-450 μm, for example, it can be 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm or 450 μm.

[0018] Preferably, the thickness of the lower adhesive film layer is 30-150 μm, for example, it can be 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm or 150 μm, etc.

[0019] Preferably, the top adhesive film layer has a multi-layer adhesive film structure.

[0020] Preferably, when the upper adhesive film layer is a multilayer adhesive film structure, the degree of crosslinking of the multilayer adhesive film structure increases sequentially along the direction from the upper adhesive film layer to the lower adhesive film layer.

[0021] Preferably, the lower adhesive film layer has a multilayer adhesive film structure.

[0022] Preferably, when the lower adhesive film layer is a multilayer adhesive film structure, the degree of crosslinking of the multilayer adhesive film structure increases sequentially along the direction from the lower adhesive film layer to the upper adhesive film layer.

[0023] The composite encapsulation film provided by this invention can be configured with an upper and lower encapsulation film layer having a multi-layered structure. By adjusting the raw material formulation in each of the upper and lower encapsulation film layers, the crosslinking degree of the encapsulation film layer can be controlled, forming upper and lower encapsulation film layers with a gradient degree of crosslinking. The outer layer of the encapsulation film has a lower degree of crosslinking, high peel strength to the battery cell and glass, and excellent wettability, which can reduce the adverse effects such as bubbles formed during the lamination process. The composite encapsulation film with this structure has excellent creep resistance and heat spot resistance.

[0024] Preferably, the raw materials for preparing the upper adhesive film layer and the raw materials for preparing the lower adhesive film layer each independently include 95-105 parts of coupling agent modified resin masterbatch A and 0.3-2 parts of polymerization inhibitor by weight.

[0025] Among them, 95-100 portions can be, for example, 95 portions, 96 portions, 98 portions, 100 portions, 102 portions, 104 portions, or 105 portions; 0.3-2 portions can be, for example, 0.3 portions, 0.5 portions, 1 portion, 1.5 portions, or 2 portions.

[0026] The upper and lower adhesive layers of the composite encapsulating film provided by this invention can use the same or different raw material formulations. Specifically, the raw material formulation can be adjusted according to the bonding performance between the film and the substrate or battery cell, so that the provided composite encapsulating film can meet different application production needs.

[0027] Preferably, the polymerization inhibitor includes organic polymerization inhibitors and / or inorganic polymerization inhibitors.

[0028] Preferably, the organic polymerization inhibitor includes any one or a combination of at least two of the following: free radical polymerization inhibitors, phenolic polymerization inhibitors, ether polymerization inhibitors, quinone polymerization inhibitors, or aromatic amine polymerization inhibitors.

[0029] Preferably, the free radical polymerization inhibitor comprises any one or a combination of at least two of the following: bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate nitroxide free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxo free radical, or 4-oxo-2,2,6,6-tetramethylpiperidin-1-oxo free radical.

[0030] Preferably, the phenolic polymerization inhibitor includes any one or a combination of at least two of hydroquinone, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butylhydroquinone, or 2-tert-butylhydroquinone.

[0031] Preferably, the quinone polymerization inhibitor includes p-benzoquinone and / or methylhydroquinone.

[0032] Preferably, the inorganic polymerization inhibitor comprises any one or a combination of at least two of ferric chloride, cuprous chloride, copper sulfate, titanium trichloride, sodium sulfate, or ammonium thiocyanate.

[0033] The present invention preferably uses 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy radical inhibitor as a polymerization inhibitor. The composite encapsulation film using this inhibitor shows the least change in crosslinking degree during subsequent irradiation and lamination processes, and is easier to effectively control the degree of crosslinking.

[0034] Preferably, the raw materials for preparing the upper adhesive film layer and the raw materials for preparing the lower adhesive film layer each independently include 0.1-1 parts of anti-aging additive and / or 0.05-0.5 parts of adhesion promoter by weight.

[0035] Among them, 0.1-1 parts can be, for example, 0.1 parts, 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts or 1 part, etc.; 0.05-0.5 parts can be, for example, 0.05 parts, 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts or 0.5 parts, etc.

[0036] Preferably, each of the bonding promoters independently comprises any one or a combination of at least two of the following: 3-isocyanopropyltrimethoxysilane, 3-isocyanopropyltriethoxysilane, 3-isocyanopropylmethyldimethoxysilane, 1,3,5-tris(trimethoxysilylpropyl)isocyanurate, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-diethylenetriaminopropyltrimethoxysilane, γ-diethylaminomethyltriethoxysilane, or N-phenylaminomethyltriethoxysilane.

[0037] Preferably, the raw materials for preparing the intermediate film layer include 95-100 parts of coupling agent-modified resin masterbatch B and 0.1-2 parts of crosslinking accelerator by weight.

[0038] Among them, 95-105 portions can be, for example, 95 portions, 96 portions, 98 portions, 100 portions, 102 portions, 104 portions, or 105 portions; 0.1-2 portions can be, for example, 0.1 portions, 0.5 portions, 0.1 portions, 1.5 portions, or 2 portions.

[0039] Preferably, the raw materials for preparing the intermediate adhesive film layer further include 0.1-1 parts by weight of an anti-aging agent, such as 0.1 parts, 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.8 parts, or 1 part, etc.

[0040] Preferably, the crosslinking accelerator comprises any one or a combination of at least two of the following: trimethylolpropane acetal acrylate, 3-ethoxytrimethylolpropane triacrylate, pentaerythritol triacrylate, methoxy polyethylene glycol monomethacrylate, 3-propanetriol triacrylate, 3-propanetrimethylolpropane triacrylate, tetrahydrofuran methacrylate, triallyl isocyanurate, or triallyl cyanurate.

[0041] The anti-aging additives used in the upper adhesive film layer, lower adhesive film layer and intermediate adhesive film layer of this invention can be selected from commercially available antioxidants and / or commercially available light stabilizers.

[0042] Preferably, the raw materials for preparing the coupling agent modified resin masterbatch A and the coupling agent modified resin masterbatch B each independently include 95-100 parts of matrix resin, 0.1-0.4 parts of initiator and 0.5-5 parts of coupling agent by weight.

[0043] Among them, 95-99 portions can be, for example, 95 portions, 96 portions, 97 portions, 98 portions, 99 portions, or 100 portions; 0.1-0.4 portions can be, for example, 0.1 portions, 0.2 portions, 0.3 portions, or 0.4 portions; 0.5-5 portions can be, for example, 0.5 portions, 1 portion, 2 portions, 3 portions, 4 portions, or 5 portions.

[0044] In this invention, the coupling agent modified resin masterbatch A and the coupling agent modified resin masterbatch B can use the same raw material formula or different raw material formulas.

[0045] Preferably, the matrix resin comprises an ethylene copolymer.

[0046] Preferably, the ethylene copolymer includes any one or a combination of at least two of POE, EVA, EBA, or EMMA.

[0047] Preferably, the melting point of the matrix resin is ≤100℃, for example, it can be 100℃, 90℃, 80℃ or 70℃, etc.

[0048] The base resin used in this invention has a melting point of ≤100℃ to meet the requirement that the resin can be fully melted during low-temperature encapsulation.

[0049] Preferably, the initiator comprises any one or a combination of at least two of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butylperoxycarbonate-2-ethylhexyl ester, tert-2-ethylhexyl peroxycarbonate-2-pentyl ester, benzoyl peroxide, dicumyl peroxide, or di(tert-butylperoxyisopropyl)benzene.

[0050] Preferably, the coupling agent comprises any one or a combination of at least two of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltriisopropylsilane, methylvinyldimethoxysilane, vinyltriacetoxysilane, γ-methacryloyloxypropyltriisopropoxysilane, γ-methacryloyloxypropylmethyldimethylsilane, 3-methacryloyloxypropyltriethoxysilane, or γ-methacryloyloxypropyltri(trimethylsilyl)silane.

[0051] In a second aspect, the present invention provides a method for preparing a composite encapsulating film as described in the first aspect, the method comprising the following steps:

[0052] The raw materials for preparing the upper adhesive film layer, lower adhesive film layer and middle adhesive film layer are mixed separately, and the composite encapsulation film is obtained by extrusion casting and curing.

[0053] Preferably, the extrusion casting temperature is ≤120℃, for example, it can be 120℃, 110℃, 100℃, 90℃ or 80℃, etc.

[0054] Preferably, the curing includes EB irradiation curing.

[0055] Preferably, the irradiation dose for EB irradiation curing is 10-80 KGy, for example, it can be 10 KGy, 20 KGy, 30 KGy, 40 KGy, 50 KGy, 60 KGy, 70 KGy or 80 KGy, etc.

[0056] Preferably, the EB irradiation curing time is 0.3-5 s, for example, it can be 0.3 s, 0.5 s, 1 s, 2 s, 3 s, 4 s or 5 s, etc.

[0057] Thirdly, the present invention provides an application of the composite encapsulating film as described in the first aspect in perovskite components.

[0058] Compared with the prior art, the present invention has at least the following beneficial effects:

[0059] (1) The composite encapsulation film provided by the present invention can achieve lamination and encapsulation of perovskite batteries at temperatures below 105°C, and crosslinking can be effectively achieved without introducing peroxide crosslinking agents that are harmful to perovskite during the crosslinking process of the composite encapsulation film.

[0060] (2) The composite encapsulation film provided by the present invention achieves the function of regulating the crosslinking degree of the film by adding a polymerization inhibitor, and sets up a multi-layer structure so that the film has both excellent adhesion and mechanical properties. Furthermore, the technical effect of regulating the crosslinking degree of the film layer can be achieved by adjusting the preparation raw material formulation in each layer of the upper and lower film layers, forming upper and lower film layers with gradient crosslinking degree to meet the diverse needs of different application scenarios for film performance.

[0061] (3) The composite encapsulation film provided by the present invention has a good appearance after lamination, and there are no defects such as bubbles, unmelted material, or delamination caused by poor adhesion. The component can withstand high temperature, can pass the hot spot test, and has excellent reliability.

[0062] (4) Through formula adjustment and structural design, the present invention can achieve the technical effect of low temperature lamination and heat resistance of the module. The peel force with the perovskite cell can reach 42-62 N / cm, and the peel force with the glass can reach 137-183 N / cm. The creep-resistant glass misalignment is only 0.3-1.7 mm, the heat spot resistance is good, and the power decay after the heat spot is only 1.21-3.21%. Attached Figure Description

[0063] Figure 1 A cross-sectional structural diagram of the composite encapsulating film provided by the present invention;

[0064] Among them, 1-upper adhesive film layer, 2-middle adhesive film layer, 3-lower adhesive film layer. Detailed Implementation

[0065] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0066] The specific information of the materials used in the following specific embodiments of the present invention is as follows:

[0067] POE, 8660, purchased from DOW;

[0068] POE, 8480, purchased from DOW;

[0069] EVA, E282PV, purchased from Hanwha;

[0070] The following are methods for preparing the coupling agent-modified resin masterbatch used in the embodiments and comparative examples of the present invention:

[0071] Modified POE masterbatch: 70 parts by weight of POE (8660), 30 parts by weight of POE (8480), 0.2 parts by weight of tert-butyl peroxycarbonate-2-ethylhexyl ester and 2 parts by weight of vinyltrimethoxysilane were mixed and reacted (reaction temperature was 250℃, reaction time was 2 min), and the modified POE masterbatch was obtained by extrusion granulation.

[0072] Modified EVA masterbatch: 95 parts by weight of EVA (E282PV), 0.4 parts by weight of benzoyl peroxide and 5 parts by weight of 3-methacryloyloxypropyltriethoxysilane were mixed and reacted (reaction temperature was 250℃, reaction time was 2 min), and the modified EVA masterbatch was obtained by extrusion granulation.

[0073] Example 1

[0074] This embodiment provides a composite encapsulating film and its preparation method. The composite encapsulating film includes an upper encapsulating film layer, an intermediate encapsulating film layer, and a lower encapsulating film layer stacked sequentially.

[0075] The raw materials for preparing the upper adhesive film layer include, by weight, 100 parts of modified POE masterbatch, 1 part of polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical, 0.5 parts of light stabilizer (770), and 0.5 parts of 3-isocyanate-propyltrimethoxysilane. The raw material formulation for the lower adhesive film layer is the same as that for the upper adhesive film layer. The degree of crosslinking of the upper and lower adhesive film layers is 5%, and the thickness is 100 μm.

[0076] The raw materials for preparing the intermediate film layer include, by weight, 100 parts of modified POE masterbatch, 0.5 parts of light stabilizer (770) and 2 parts of trimethylolpropane acetal acrylate. The crosslinking degree of the intermediate layer is 80% and the thickness is 350 μm.

[0077] The preparation method includes the following steps:

[0078] The raw materials for preparing the upper adhesive film layer, lower adhesive film layer and middle adhesive film layer are mixed separately, extruded and cast at a temperature of 100°C, and then cured by EB irradiation at a dose of 50 KGy for a curing time of 2 s to obtain the composite encapsulation film.

[0079] Example 2

[0080] This embodiment provides a composite encapsulating film and its preparation method. The composite encapsulating film includes an upper encapsulating film layer, an intermediate encapsulating film layer, and a lower encapsulating film layer stacked sequentially.

[0081] The raw materials for preparing the upper adhesive film layer include, by weight, 100 parts of modified EVA masterbatch, 0.5 parts of p-benzoquinone, 1 part of light stabilizer (770), and 0.2 parts of γ-aminopropylmethyldiethoxysilane. The raw material formulation for the lower adhesive film layer is the same as that for the upper adhesive film layer. The degree of crosslinking of the upper and lower adhesive film layers is 10%, and the thickness is 80 μm.

[0082] The raw materials for preparing the intermediate film layer include 100 parts of modified EVA masterbatch, 1 part of light stabilizer (770) and 1 part of trimethylolpropane acetal acrylate by weight. The crosslinking degree of the intermediate film layer is 90% and the thickness is 400 μm.

[0083] The preparation method is the same as in Example 1.

[0084] Example 3

[0085] This embodiment provides a composite encapsulating film and its preparation method. The composite encapsulating film includes an upper encapsulating film layer, an intermediate encapsulating film layer, and a lower encapsulating film layer stacked sequentially.

[0086] The raw materials for preparing the upper adhesive film layer include, by weight, 100 parts of modified POE masterbatch, 2 parts of cuprous chloride, and 0.05 parts of 1,3,5-tris(trimethoxysilylpropyl)isocyanurate. The preparation formula for the lower adhesive film layer is the same as that for the upper adhesive film layer. The degree of crosslinking of the upper and lower adhesive film layers is 10%, and the thickness is 80 μm.

[0087] The raw materials for preparing the intermediate film layer include 100 parts of modified POE masterbatch and 0.22 parts of trimethylolpropane formal acrylate by weight. The degree of crosslinking of the intermediate film layer is 50%, and the thickness is 400 μm.

[0088] The preparation method is the same as in Example 1.

[0089] Example 4

[0090] This embodiment provides a composite encapsulating film and its preparation method. The composite encapsulating film includes a first upper adhesive film layer, a second upper adhesive film layer, an intermediate adhesive film layer, a first lower adhesive film layer, and a second lower adhesive film layer stacked sequentially.

[0091] The raw materials for preparing the first topcoat layer include, by weight, 100 parts of modified POE masterbatch, 1 part of polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical, 0.5 parts of light stabilizer (770) and 0.5 parts of 3-isocyanate-propyltrimethoxysilane. The degree of crosslinking of the first topcoat layer is 5%, and the thickness is 50 μm.

[0092] The raw materials for preparing the second topcoat layer include, by weight, 100 parts of modified POE masterbatch, 0.5 parts of polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical, 0.5 parts of light stabilizer (770) and 0.2 parts of 3-isocyanate-propyltrimethoxysilane. The degree of crosslinking of the second topcoat layer is 25%, and the thickness is 50 μm.

[0093] The raw materials for preparing the intermediate film layer include 100 parts of modified POE masterbatch, 1 part of trimethylolpropane acetal acrylate and 0.5 parts of light stabilizer (770) by weight. The crosslinking degree of the intermediate film layer is 80% and the thickness is 350 μm.

[0094] The raw materials for preparing the first lower adhesive film layer include, by weight, 100 parts of modified POE masterbatch, 0.5 parts of polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical, 0.5 parts of light stabilizer (770) and 0.2 parts of 3-isocyanate-propyltrimethoxysilane. The degree of crosslinking of the first lower adhesive film layer is 25%, and the thickness is 50 μm.

[0095] The raw materials for preparing the second lower adhesive film layer include, by weight, 100 parts of modified POE masterbatch, 1 part of polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical, 0.5 parts of light stabilizer (770) and 0.5 parts of 3-isocyanate-propyltrimethoxysilane. The degree of crosslinking of the first lower adhesive film layer is 5%, and the thickness is 50 μm.

[0096] The preparation method includes the following steps:

[0097] The raw materials for preparing the first top adhesive film layer, the second top adhesive film layer, the first bottom adhesive film layer, the second bottom adhesive film layer, and the intermediate adhesive film layer are mixed, and then extruded, cast, and cured by EB irradiation with an irradiation dose of 50 KGy and a curing time of 2 s to obtain the composite encapsulation film.

[0098] Example 5

[0099] This embodiment provides a composite encapsulating film and its preparation method. The composite encapsulating film includes a first upper adhesive film layer, a second upper adhesive film layer, an intermediate adhesive film layer, a first lower adhesive film layer, and a second lower adhesive film layer stacked sequentially.

[0100] The raw materials for preparing the first topcoat layer include, by weight, 100 parts of modified POE masterbatch, 1 part of polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical, 0.5 parts of light stabilizer (770) and 0.5 parts of 3-isocyanate-propyltrimethoxysilane. The degree of crosslinking of the first topcoat layer is 0%, and the thickness is 50 μm.

[0101] The raw materials for preparing the second topcoat layer include, by weight, 100 parts of modified POE masterbatch, 2 parts of polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical, 0.5 parts of light stabilizer (770) and 0.2 parts of 3-isocyanate-propyltrimethoxysilane. The degree of crosslinking of the second topcoat layer is 5%, and the thickness is 50 μm.

[0102] The raw materials for preparing the intermediate film layer include 100 parts of modified POE masterbatch, 1 part of trimethylolpropane acetal acrylate and 0.5 parts of light stabilizer (770) by weight. The crosslinking degree of the intermediate film layer is 80% and the thickness is 350 μm.

[0103] The raw materials for preparing the first lower adhesive film layer include, by weight, 100 parts of modified POE masterbatch, 1 part of polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical, 0.5 parts of light stabilizer (770) and 0.5 parts of 3-isocyanate-propyltrimethoxysilane. The degree of crosslinking of the first lower adhesive film layer is 5%, and the thickness is 50 μm.

[0104] The raw materials for preparing the second lower adhesive film layer include, by weight, 100 parts of modified POE masterbatch, 2 parts of polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical, 0.5 parts of light stabilizer (770), and 0.2 parts of 3-isocyanate-propyltrimethoxysilane. The crosslinking degree of the first lower adhesive film layer is 0%, and the thickness is 50 μm.

[0105] The preparation method includes the following steps:

[0106] The raw materials for preparing the first top adhesive film layer, the second top adhesive film layer, the first bottom adhesive film layer, the second bottom adhesive film layer and the intermediate adhesive film layer are mixed, and then extruded and cast, cured by EB irradiation with an irradiation dose of 50 KGy and a curing time of 2s to obtain the composite encapsulation film.

[0107] Example 6

[0108] This embodiment provides a composite encapsulating film and its preparation method. The difference from Embodiment 1 is that the amount of polymerization inhibitor in the raw materials for preparing the upper and lower adhesive film layers is adjusted to 2 parts by weight.

[0109] Example 7

[0110] This embodiment provides a composite encapsulating film and its preparation method. The difference from Embodiment 1 is that the amount of polymerization inhibitor in the raw materials for preparing the upper and lower adhesive film layers is adjusted to 0.3 parts by weight.

[0111] Example 8

[0112] This embodiment provides a composite encapsulating film and its preparation method. The difference from Embodiment 1 is that the polymerization inhibitor is replaced with p-benzoquinone in the raw materials for preparing the upper and lower adhesive film layers.

[0113] Comparative Example 1

[0114] This comparative example provides a composite encapsulating film and its preparation method. The difference from Example 1 is that the raw materials used to prepare the upper and lower encapsulating film layers do not contain polymerization inhibitors.

[0115] Comparative Example 2

[0116] This comparative example provides an encapsulating film and its preparation method. The raw materials for preparing the encapsulating film include, by weight, 100 parts of modified POE masterbatch, 1 part of polymerization inhibitor 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical, 0.5 parts of light stabilizer (770), and 0.5 parts of 3-isocyanate-propyltrimethoxysilane. The degree of crosslinking of the film is 5%, and the thickness is 550 μm.

[0117] The preparation method includes the following steps:

[0118] The raw materials for preparing the composite encapsulating film are mixed, extruded and cast, and then cured by EB irradiation with an irradiation dose of 50 KGy and a curing time of 2 s to obtain the composite encapsulating film.

[0119] Comparative Example 3

[0120] This comparative example provides a composite encapsulating film and its preparation method. The difference from Example 1 is that the modified POE coupling agent-modified resin masterbatch in the raw materials for preparing the upper, lower, and intermediate encapsulating film layers is replaced with unmodified POE resin (8660).

[0121] Comparative Example 4

[0122] This comparative example provides a composite encapsulating film and its preparation method. The difference from Example 1 is that the amount of polymerization inhibitor in the raw materials for preparing the upper and lower encapsulating film layers is adjusted to 5 parts by weight.

[0123] Comparative Example 5

[0124] This comparative example provides a composite encapsulating film and its preparation method. The difference from Example 1 is that the amount of polymerization inhibitor in the raw materials for preparing the upper and lower encapsulating film layers is adjusted to 0.1 parts by weight.

[0125] Test methods

[0126] The composite encapsulating films and encapsulating films prepared in Examples 1-8 and Comparative Examples 1-5 were laminated with glass and perovskite solar cells at 105°C for 20 min to obtain the corresponding photovoltaic modules.

[0127] The composite encapsulating films prepared in Examples 1-8 and Comparative Examples 1-5, and their corresponding photovoltaic modules, were subjected to the following performance tests:

[0128] (1) Peel strength: Test the peel strength between the composite encapsulation film and the battery cell and glass;

[0129] Peel force from perovskite solar cells: Tested according to GB / T 29848-2018;

[0130] Peel strength from glass: Tested according to GB / T 29848-2018;

[0131] (2) Degree of crosslinking: Tested according to GB / T 29848-2018;

[0132] (3) Creep resistance: Glass, the composite encapsulating film prepared in Examples 1-8 and Comparative Examples 1-5, and glass were laminated to form a photovoltaic module. The lamination process conditions were: vacuum lamination at 120°C for 10 min. The junction box was fixed to one side of the glass with glue. The photovoltaic module was then vertically suspended in an environmental chamber at 110°C for 7 days. The misalignment distance between the two glass panes was tested.

[0133] (4) Heat spot resistance: Tested according to IEC 61215:2021.

[0134] The composite encapsulating films, encapsulating films, and their corresponding photovoltaic modules provided in Examples 1-8 and Comparative Examples 1-5 were tested according to the above test methods. The test results are shown in Table 1.

[0135] Table 1

[0136]

[0137] According to the data in Table 1:

[0138] (1) As can be seen from Examples 1 to 8, the present invention can achieve the technical effect of low-temperature lamination and heat-resistant modules through formula adjustment and structural design. The peel force with perovskite solar cells can reach 42-62 N / cm, and the peel force with glass can reach 137-183 N / cm. Moreover, the creep-resistant glass misalignment is only 0.3-1.7 mm, the heat spot resistance is good, and the power decay after the heat spot is only 1.21-3.21%.

[0139] (2) As can be seen from Examples 1 and 4-5, the present invention further sets up an upper adhesive film layer and a lower adhesive film layer with a multi-layer structure, and achieves the technical effect of controlling the crosslinking degree of the adhesive film layer by adjusting the raw material formulation in each adhesive film layer of the upper and lower adhesive film layers, forming an upper and lower adhesive film layer with a gradient crosslinking degree, which can reduce the adverse effects such as bubbles formed during the lamination process, and the composite encapsulation adhesive film has better creep resistance and heat resistance.

[0140] (3) As can be seen from Examples 1, 6-7 and Comparative Examples 4-5, by further controlling the amount of polymerization inhibitor in the film layer, the present invention increases the amount of polymerization inhibitor, which corresponds to a decrease in the degree of crosslinking of the film layer and a higher peel force with the perovskite solar cell and glass, but the creep resistance and heat spot resistance of the film deteriorate.

[0141] (4) As can be seen from Examples 1 and 10, the present invention preferably uses 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxy free radical inhibitor. The crosslinking degree of the composite encapsulation film using the modified inhibitor changes the least during subsequent irradiation and lamination processes, and it is easier to achieve effective control of the crosslinking degree.

[0142] (5) As can be seen from Example 1 and Comparative Example 1, the present invention can achieve the technical effect of cross-linking of the adhesive film before lamination through multi-layer structure design. However, when no cross-linking inhibitor is used or lacks cross-linking, it cannot achieve the technical effect of controlling the cross-linking of the adhesive film. The degree of cross-linking of the adhesive film is large, and the peeling force with the perovskite solar cell and glass is severely deteriorated.

[0143] (6) As can be seen from Example 1 and Comparative Example 2, when the adhesive film is a single-layer structure, although it has good adhesion performance, the overall mechanical properties of the adhesive film are poor due to the lack of an intermediate layer with a high degree of cross-linking, and it does not have the properties of creep resistance and heat spot resistance.

[0144] (7) As can be seen from Example 1 and Comparative Example 3, when the resin masterbatch used in this invention is unmodified POE resin, the film cannot be pre-crosslinked and cannot be effectively formed without the addition of an extra crosslinking agent.

[0145] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A composite encapsulating film, characterized in that, The composite encapsulating film includes an upper adhesive film layer, an intermediate adhesive film layer, and a lower adhesive film layer stacked sequentially. The degree of crosslinking of the intermediate adhesive film layer is greater than that of the upper adhesive film layer, and the degree of crosslinking of the intermediate adhesive film layer is greater than that of the lower adhesive film layer; The raw materials for preparing the upper and lower adhesive film layers each independently include coupling agent-modified resin masterbatch A and a polymerization inhibitor; The raw materials for preparing the intermediate film layer include coupling agent-modified resin masterbatch B and crosslinking accelerator.

2. The composite encapsulating film according to claim 1, characterized in that, The degree of crosslinking of the adhesive film layer is 0-30%; Preferably, the degree of crosslinking of the intermediate adhesive film layer is 30-90%; Preferably, the degree of crosslinking of the lower adhesive film layer is 0-30%; Preferably, the thickness of the adhesive film layer is 30-150 μm; Preferably, the thickness of the intermediate adhesive film layer is 150-450 μm; Preferably, the thickness of the lower adhesive film layer is 30-150 μm.

3. The composite encapsulating film according to claim 1 or 2, characterized in that, The adhesive film layer has a multi-layer adhesive film structure; Preferably, when the upper adhesive film layer is a multilayer adhesive film structure, the degree of crosslinking of the multilayer adhesive film structure increases sequentially along the direction from the upper adhesive film layer to the lower adhesive film layer; Preferably, the lower adhesive film layer has a multilayer adhesive film structure; Preferably, when the lower adhesive film layer is a multilayer adhesive film structure, the degree of crosslinking of the multilayer adhesive film structure increases sequentially along the direction from the lower adhesive film layer to the upper adhesive film layer.

4. The composite encapsulating film according to any one of claims 1-3, characterized in that, The raw materials for preparing the upper adhesive film layer and the raw materials for preparing the lower adhesive film layer each independently include, by weight, 95-105 parts of coupling agent modified resin masterbatch A and 0.3-2 parts of polymerization inhibitor; Preferably, the polymerization inhibitor includes organic polymerization inhibitors and / or inorganic polymerization inhibitors; Preferably, the organic polymerization inhibitor includes any one or a combination of at least two of the following: free radical polymerization inhibitors, phenolic polymerization inhibitors, ether polymerization inhibitors, quinone polymerization inhibitors, or aromatic amine polymerization inhibitors; Preferably, the free radical polymerization inhibitor comprises any one or a combination of at least two of the following: bis(2,2,6,6-tetramethyl-4-piperidinyl) sebacate nitroxide free radical, 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxo free radical, or 4-oxo-2,2,6,6-tetramethylpiperidin-1-oxo free radical. Preferably, the phenolic polymerization inhibitor includes any one or a combination of at least two of hydroquinone, p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 2,5-di-tert-butylhydroquinone, or 2-tert-butylhydroquinone. Preferably, the quinone polymerization inhibitor includes p-benzoquinone and / or methylhydroquinone; Preferably, the inorganic polymerization inhibitor comprises any one or a combination of at least two of ferric chloride, cuprous chloride, copper sulfate, titanium trichloride, sodium sulfate, or ammonium thiocyanate.

5. The composite encapsulating film according to any one of claims 1-4, characterized in that, The raw materials for preparing the upper adhesive film layer and the raw materials for preparing the lower adhesive film layer each independently include, by weight, 0.1-1 parts of anti-aging additive and / or 0.05-0.5 parts of adhesion promoter; Preferably, each of the bonding promoters independently comprises any one or a combination of at least two of the following: 3-isocyanopropyltrimethoxysilane, 3-isocyanopropyltriethoxysilane, 3-isocyanopropylmethyldimethoxysilane, 1,3,5-tris(trimethoxysilylpropyl)isocyanurate, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-diethylenetriaminopropyltrimethoxysilane, γ-diethylaminomethyltriethoxysilane, or N-phenylaminomethyltriethoxysilane.

6. The composite encapsulating film according to any one of claims 1-5, characterized in that, The raw materials for preparing the intermediate film layer include, by weight, 95-100 parts of coupling agent modified resin masterbatch B and 0.1-2 parts of crosslinking accelerator; Preferably, the raw materials for preparing the intermediate adhesive film layer further include 0.1-1 parts by weight of an anti-aging additive; Preferably, the crosslinking accelerator comprises any one or a combination of at least two of the following: trimethylolpropane acetal acrylate, 3-ethoxytrimethylolpropane triacrylate, pentaerythritol triacrylate, methoxy polyethylene glycol monomethacrylate, 3-propanetriol triacrylate, 3-propanetrimethylolpropane triacrylate, tetrahydrofuran methacrylate, triallyl isocyanurate, or triallyl cyanurate.

7. The composite encapsulating film according to any one of claims 1-6, characterized in that, The raw materials for preparing the coupling agent modified resin masterbatch A and the coupling agent modified resin masterbatch B, by weight, each independently include 95-105 parts of matrix resin, 0.1-0.4 parts of initiator and 0.5-5 parts of coupling agent. Preferably, the matrix resin comprises an ethylene copolymer; Preferably, the ethylene copolymer includes any one or a combination of at least two of POE, EVA, EBA or EMMA; Preferably, the melting point of the matrix resin is ≤100℃; Preferably, the initiator comprises any one or a combination of at least two of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butylperoxycarbonate-2-ethylhexyl ester, tert-2-ethylhexyl peroxycarbonate-2-pentyl ester, benzoyl peroxide, dicumyl peroxide or di(tert-butylperoxyisopropyl)benzene. Preferably, the coupling agent comprises any one or a combination of at least two of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri(2-methoxyethoxy)silane, vinyltriisopropylsilane, methylvinyldimethoxysilane, vinyltriacetoxysilane, γ-methacryloyloxypropyltriisopropoxysilane, γ-methacryloyloxypropylmethyldimethylsilane, 3-methacryloyloxypropyltriethoxysilane, or γ-methacryloyloxypropyltri(trimethylsilyl)silane.

8. A method for preparing a composite encapsulating film as described in any one of claims 1-7, characterized in that, The preparation method includes the following steps: The raw materials for preparing the upper adhesive film layer, lower adhesive film layer and middle adhesive film layer are mixed separately, and the composite encapsulation film is obtained by extrusion casting and curing.

9. The method for preparing the composite encapsulating film according to claim 8, characterized in that, The extrusion casting temperature is ≤120℃; Preferably, the curing includes EB irradiation curing; Preferably, the irradiation dose for EB irradiation curing is 10-80 KGy; Preferably, the EB irradiation curing time is 0.3-5 s.

10. The application of a composite encapsulating film as described in any one of claims 1-7 in a perovskite module.

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