Frame packaging adhesive, frame-packaged photovoltaic module and preparation method of frame-packaged photovoltaic module

Abstract

The invention relates to the technical field of photovoltaics, in particular to a frame packaging adhesive, a frame-packaged photovoltaic module and a preparation method of the frame-packaged photovoltaic module. The frame packaging adhesive comprises a frame bonding layer, a skeleton layer and a photovoltaic bonding layer, the ML value of the frame bonding layer at a first temperature is not lower than 0.15, and the forming raw material of the frame bonding layer comprises first matrix resin; the ML value of the photovoltaic bonding layer at the first temperature is not lower than 0.10, the ML value of the photovoltaic bonding layer is lower than the ML value of the frame bonding layer, and the forming raw material of the photovoltaic bonding layer comprises second matrix resin; the first temperature is not lower than 140 DEG C; the forming raw material of the skeleton layer comprises third matrix resin; the melting point of the first matrix resin and the melting point of the second matrix resin are both lower than the melting point of the third matrix resin. According to the frame packaging adhesive disclosed by the invention, through a three-layer structure of the relatively low-melting-point low-fluidity photovoltaic bonding layer, the relatively high-melting-point framework layer and the relatively low-melting-point lower-fluidity frame bonding layer, the problem of adhesive overflow in a hot-pressing process of a frame packaging photovoltaic module is solved.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a frame encapsulation adhesive, a frame-encapsulated photovoltaic component and a preparation method thereof. Background Art

[0002] Photovoltaic modules, also known as solar panels, are one of the core components of solar power generation systems. They are primarily composed of glass, photovoltaic film, and solar cell arrays. Because the cell arrays used in photovoltaic modules are relatively fragile, they are typically surrounded by a frame to effectively protect the central cell array.

[0003] In the prior art, the frame installation method is usually: after the photovoltaic modules are laminated and formed, silicone is applied to the frame for extrusion installation, and then cured by moisture. This method has certain disadvantages, such as (1) glue overflow problem. During extrusion installation, silicone is easy to overflow, which is not conducive to the packaging of small-sized structural parts; (2) poor water barrier performance problem. The water vapor transmission rate of 1mm silicone reaches 40g / (m 2 ·24h), high water vapor transmission rate; (3) manufacturing inconvenience and cost issues. Since this installation method requires lamination and framing before moisture curing, it will lead to an increase in production space and an increase in the inventory of work-in-progress products, which will ultimately lead to an increase in costs.

[0004] At present, some existing technologies have developed some new frame packaging structures, but they have not been able to solve the above problems well. For example, the patent document with publication number CN114584059A discloses a frame-encapsulated solar panel. In some embodiments, the remaining part of the encapsulation adhesive layer of the first encapsulation frame is bonded to the remaining part of the encapsulation adhesive layer of the second encapsulation frame at the periphery of the solar panel, thereby wrapping the outer side of the solar panel; in other embodiments, the remaining part of the encapsulation adhesive layer of the encapsulation frame is bonded to the extended area of ​​the adhesive layer in the solar panel at the periphery of the solar panel, thereby wrapping the outer side of the solar panel. For example, the materials of the adhesive layer and the adhesive layer are independently selected from any one or a combination of at least two of EVA, POE or PVB. In this prior art, whether the encapsulation adhesive layer is bonded to the encapsulation adhesive layer or the encapsulation adhesive layer is bonded to the adhesive layer in the solar panel, conventional adhesives are bonded to conventional adhesives. The melting point of these conventional adhesives is relatively low. At relatively high hot pressing temperatures, the fluidity of the adhesive is enhanced, and the problem of adhesive overflow is still prone to occur. At the same time, the bonding of conventional adhesives alone does not improve the water barrier effect. Furthermore, in the prior art, the adhesive layer needs to be extended circumferentially to form an extended area for bonding, which results in a poor appearance.

[0005] To address the issue of adhesive overflow, patent publication CN113698877A discloses a pair of encapsulating films for photovoltaic module encapsulation. The films comprise at least a first encapsulating film and a second encapsulating film, with the absolute difference in ML values ​​between them ranging from 0 to 0.35 dN·m. The first encapsulating film is positioned on the light-receiving side, while the second encapsulating film is positioned on the backlight side. The ML values ​​of the first encapsulating film range from 0.08 to 0.5 dN·m, while those of the second encapsulating film range from 0.08 to 0.85 dN·m, with the ML values ​​measured at a temperature of 145°C. This prior art is primarily suitable for bonding glass or TPT backsheets to solar cells in photovoltaic modules. However, its bonding and anti-overflow properties are limited when applied between a frame (typically metal or plastic) and a photovoltaic module. Summary of the Invention

[0006] The present invention aims to solve the above problems and provide a frame encapsulation glue, a frame-encapsulated photovoltaic module and a preparation method thereof that is suitable for bonding between frames and photovoltaic modules, has good adhesion, is not easy to overflow, has a regular appearance, and in some embodiments also has a good water-blocking effect.

[0007] The technical solution to solve the problem of the present invention is: First aspect , provides a frame encapsulation glue, including a frame adhesive layer for bonding to a frame and a photovoltaic adhesive layer for bonding to a photovoltaic module, the ML value of the frame adhesive layer at a first temperature is not less than 0.15, and the raw material for forming the frame adhesive layer includes a first matrix resin; the ML value of the photovoltaic adhesive layer at the first temperature is not less than 0.10, and the ML value of the photovoltaic adhesive layer is lower than the ML value of the frame adhesive layer, and the raw material for forming the photovoltaic adhesive layer includes a second matrix resin; the first temperature is not less than 140°C; the frame encapsulation glue also includes a skeleton layer arranged between the frame adhesive layer and the photovoltaic adhesive layer, and the raw material for forming the skeleton layer includes a third matrix resin; the melting point of the first matrix resin is lower than the melting point of the third matrix resin, and the melting point of the second matrix resin is lower than the melting point of the third matrix resin.

[0008] Among them, ML value refers to Mooney viscosity. The higher the ML value, the worse the fluidity.

[0009] In the present application, a frame encapsulation adhesive with a three-layer structure, specifically a frame adhesive layer + a skeleton layer + a photovoltaic adhesive layer, is provided. The adhesive layer has asymmetric low fluidity and a relatively low melting point on both sides, and a relatively high melting point skeleton layer in the middle. This prevents the problem of adhesive overflow when used for frame encapsulation of photovoltaic modules without affecting the bonding strength.

[0010] The principle can be specifically speculated as follows: the vacuum hot pressing temperature of the frame encapsulation photovoltaic module is approximately 140~160℃, and the frame adhesive layer and photovoltaic adhesive layer of the present application have low fluidity at the vacuum hot pressing temperature to avoid glue overflow. At the same time, the melting point of the third matrix resin of the skeleton layer is higher than the melting point of the first matrix resin of the frame adhesive layer and the second matrix resin of the photovoltaic adhesive layer. When the frame adhesive layer and the photovoltaic adhesive layer melt and flow for bonding, the skeleton layer is still in a stable rigid support state, thereby being able to restrain (the adhesive layer with a lower melting point begins to melt first to form a liquid film with relatively better fluidity. This liquid film can fill the tiny gaps and unevenness between the adhesive layer and the skeleton layer, and even wet and penetrate into the skeleton layer with a higher melting point, increasing the contact area and interaction force between the two layers, and even forming a micro-cross-linked state, which is restraining) the flow of the frame adhesive layer and the photovoltaic adhesive layer, further reducing the risk of glue overflow, and improving the integrity of the frame encapsulation glue so that it has better mechanical structural strength, especially tensile strength. When the skeleton layer is melted, although its own ML value is not restricted, the low-fluidity frame adhesive layer and photovoltaic adhesive layer on both sides of the skeleton layer will reversely restrict the flow of the skeleton layer to prevent glue overflow. In addition, the frame adhesive layer and the photovoltaic adhesive layer have different fluidities at the same temperature. On the one hand, they are adapted to their bonding objects: the thermal expansion coefficient of the frame is usually higher than that of the photovoltaic module. The relatively high-fluidity photovoltaic adhesive layer can better adapt to the slight deformation of the photovoltaic module and avoid being squeezed out. The relatively low-fluidity frame adhesive layer can still maintain a high viscosity when the frame expands due to heat, reducing the colloid extrusion caused by the expansion of the frame; on the other hand, asymmetric flow resistance is formed on both sides of the skeleton layer, forming a fluidity gradient in the vertical direction. The relatively high-fluidity photovoltaic adhesive layer has a tendency to penetrate through the skeleton layer to the relatively low-fluidity frame adhesive layer, which increases the integrity of the encapsulation glue, and the overall fluidity is relatively moderate, slowing down the speed of the overall migration of the colloid to the edge, thereby suppressing glue overflow.

[0011] In particular, based on the condition that the vacuum hot pressing temperature for the frame-encapsulated photovoltaic module is approximately 140-160°C, in some preferred embodiments, the first temperature can be 140°C. The higher the first temperature, the higher the requirement for low fluidity of the frame adhesive layer and the photovoltaic adhesive layer. Low fluidity of the frame adhesive layer and the photovoltaic adhesive layer can solve the problem of adhesive overflow, but the lower the fluidity, the better. When the fluidity is too low, it will affect the bonding effect of the frame encapsulation adhesive between the frame and the photovoltaic module.

[0012] In some preferred embodiments, the ML value of the frame adhesive layer at 140°C is not less than 0.15; the ML value of the photovoltaic adhesive layer at 140°C is not less than 0.10, and the ML value of the photovoltaic adhesive layer at 140°C is lower than the ML value of the frame adhesive layer at 140°C; so as to achieve the effect of preventing glue overflow when it is used for frame encapsulation of photovoltaic components without affecting the bonding force.

[0013] Preferably, the ML value of the frame adhesive layer at 140°C is 0.15~30; the ML value of the photovoltaic adhesive layer at 140°C is 0.10~30, and the ML value of the photovoltaic adhesive layer at 140°C is lower than the ML value of the frame adhesive layer at 140°C.

[0014] For the frame adhesive layer In principle, the selection of the first matrix resin in the forming raw materials is not restricted, as long as it has a suitable melting point, can make the frame adhesive layer reach the corresponding ML value at the first temperature, and has adhesive properties.

[0015] In some preferred embodiments, the melt index of the first matrix resin at 190°C and 2.16 kg load is less than 20 g / 10 min, and the melt index directly reflects the fluidity. "190°C and 2.16 kg load" are international standard test parameters.

[0016] Preferably, the first matrix resin is selected from at least one of a polyolefin resin and a modified polyolefin resin. Using a polyolefin-based resin facilitates control of its melt index by controlling its molecular weight, crystallinity, or copolymer segment length, while also better meeting the requirements of the present invention in terms of adhesion and fluidity. Preferably, the polyolefin resin is selected from at least one of polyethylene (PE), ethylene-vinyl acetate copolymer (EVA), polyethylene-octene co-elastomer (POE), and modified POE; the modified POE may be grafted POE, blended POE, radiation-crosslinked POE, or chemically crosslinked POE. The modified polyolefin resin comprises a main chain and side chains, the main chain being the polyolefin resin; preferably, the side chains are acrylates with 4 to 18 carbon atoms, and / or the surface energy of the modified polyolefin resin is 45 to 55 mN / m.

[0017] Further preferably, the first matrix resin is POE, which has good water-blocking properties. At the same time, in an embodiment using a metal frame, POE is less susceptible to aging than EVA and will not decompose acetic acid to corrode the frame.

[0018] The difference in melting points between the first matrix resin and the third matrix resin is not limited. For example, the difference in melting points between the first matrix resin and the third matrix resin is 10-100°C, preferably 20-90°C, and more preferably 30-80°C.

[0019] The amount of the first matrix resin is not limited. For example, the raw materials for forming the frame adhesive layer include 90wt%~100wt% of the first matrix resin, such as 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, and 100wt%.

[0020] In some preferred embodiments, the raw materials for forming the frame adhesive layer further include an additive to compensate for any deficiencies in the first base resin. The choice of additive is not limited and can be appropriately selected based on considerations such as crosslinking, antioxidant properties, and light stability. Preferably, the first additive includes at least one of a crosslinking agent, a co-crosslinking agent, a silane coupling agent, an antioxidant, and a light stabilizer.

[0021] For example, the crosslinking agent can be selected from tert-butyl peroxy isopropyl carbonate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert-butyl peroxy-2-ethylhexyl carbonate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, At least one of (tert-amylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-amylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, 2,2-bis(tert-butylperoxy)butane, tert-amyl peroxy-2-ethylhexyl carbonate, 2,5-dimethyl-2,5-bis(benzoyl peroxide)-hexane, tert-amyl peroxy-(2-ethylhexyl) carbonate, and tert-butyl peroxy-3,5,5-trimethylhexanoate.

[0022] The auxiliary cross-linking agent may be selected from at least one of triallyl cyanurate, trimethylolpropane trimethacrylate, triallyl isocyanurate, ethoxy pentaerythritol tetraacrylate, ethoxylated trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and pentaerythritol triacrylate.

[0023] The silane coupling agent can be selected from at least one of γ-glycidoxypropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltri(2-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and N-(β-aminoethyl)-γ-aminopropyltriethoxysilane.

[0024] The antioxidant can be selected from at least one of didodecenyl p-cresol, 3,5-di-tert-butyl-4-hydroxyphenylpropionate, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, N,N'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine, 2,6-di-tert-butyl-p-cresol, tris(2,4-di-tert-butylphenyl)phosphite, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid.

[0025] The light stabilizer can be selected from at least one of 3,5-di-tert-butyl-4-hydroxy-benzoic acid hexadecyl ester, tris(1,2,2,6,6-pentamethyl-4-piperidinyl)phosphite, bis-2,2,6,6-tetramethylpiperidinol sebacate, bis-1-decyloxy-2,2,6,6-tetramethylpiperidin-4-ol sebacate, a polymer of succinic acid and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol, N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine, and a polymer of morpholine-2,4,6-trichloro-1,3,5-triazine.

[0026] The amount of the additive is not limited and can be added in an appropriate amount based on actual needs. For example, the raw materials for forming the frame adhesive layer include 0.01wt% to 10wt% of the additive, such as 0.01wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, and 10wt%.

[0027] In principle, the thickness ratio of the frame adhesive layer to the frame encapsulant is not limited, but an appropriate thickness ratio can balance the frame encapsulant's anti-overflow performance and its adhesion to the frame. In some preferred embodiments, the thickness of the frame adhesive layer accounts for 10% to 50% of the thickness of the frame encapsulant; for example, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%. Preferably, the thickness of the frame adhesive layer accounts for 20% to 40% of the thickness of the frame encapsulant.

[0028] For photovoltaic bonding layersIn principle, the selection of the second matrix resin in the forming raw materials is not restricted, as long as it has a suitable melting point, can make the photovoltaic bonding layer reach the corresponding ML value at the first temperature, and has bonding properties.

[0029] In some preferred embodiments, the melt index of the second matrix resin at 190°C and 2.16 kg load is less than 20 g / 10 min, and the melt index directly reflects the fluidity. "190°C and 2.16 kg load" are international standard test parameters.

[0030] Preferably, the second matrix resin is selected from a polyolefin resin, which facilitates control of its melt index by controlling the molecular weight, crystallinity, or length of the copolymer segments, while also better meeting the requirements of this application in terms of adhesion and fluidity. Preferably, the second matrix resin is selected from at least one of polyethylene (PE), ethylene-vinyl acetate copolymer (EVA), polyethylene-octene co-elastomer (POE), and modified POE; the modified POE may be grafted POE, blended POE, radiation-crosslinked POE, chemically crosslinked POE, etc.

[0031] Further preferably, the second matrix resin is POE, which has better water barrier properties and adhesion.

[0032] The difference in melting points between the second matrix resin and the third matrix resin is not limited. For example, the difference in melting points between the second matrix resin and the third matrix resin is 10-100°C, preferably 20-90°C, and more preferably 30-80°C.

[0033] The amount of the second matrix resin is not limited. For example, the raw materials for forming the photovoltaic bonding layer include 90wt% to 100wt% of the second matrix resin, such as 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, and 100wt%.

[0034] In some preferred embodiments, the raw materials of the photovoltaic bonding layer further include an auxiliary agent to compensate for possible deficiencies in the second matrix resin. The selection of the auxiliary agent is not limited and can be appropriately selected based on considerations such as cross-linking, anti-oxidation, and light stability. For example, the auxiliary agent includes at least one of a cross-linking agent, a co-cross-linking agent, a silane coupling agent, an antioxidant, and a light stabilizer. The specific selection of the cross-linking agent, the co-cross-linking agent, the silane coupling agent, the antioxidant, and the light stabilizer can refer to the selection of the auxiliary agent in the above-mentioned frame bonding layer.

[0035] The amount of the additive is not limited and can be added in an appropriate amount based on actual needs. For example, the raw materials for forming the photovoltaic adhesive layer include 0.01wt% to 10wt% of the additive, such as 0.01wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, and 10wt%.

[0036] The thickness of the photovoltaic adhesive layer in the frame encapsulant is generally unrestricted, but an appropriate ratio can balance the frame encapsulant's anti-overflow properties with its adhesion to the photovoltaic module. In some preferred embodiments, the thickness of the photovoltaic adhesive layer accounts for 10% to 50% of the frame encapsulant's thickness; illustratively, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, or 50%. Preferably, the thickness of the photovoltaic adhesive layer accounts for 20% to 40% of the frame encapsulant's thickness.

[0037] In addition, in some preferred embodiments, at least one of the frame adhesive layer and the photovoltaic adhesive layer has a certain degree of pre-crosslinking, which helps to further control the fluidity of the encapsulation glue and prevent glue overflow when the frame encapsulates the photovoltaic module, while slowing down the shrinkage and stress during the curing process, shortening the curing time and improving production efficiency.

[0038] Preferably, the frame adhesive layer and the photovoltaic adhesive layer each have a pre-crosslinking degree.

[0039] Further preferably, the pre-crosslinking degree of the frame adhesive layer is 0-30%, and / or the pre-crosslinking degree of the photovoltaic adhesive layer is 0-30%.

[0040] For the skeleton layer In some preferred embodiments, the melting point of the third matrix resin is 110-150°C, which is suitable for the vacuum hot pressing temperature during the frame encapsulation process of photovoltaic modules. If the melting point of the third matrix resin is too low, it will melt too quickly, affecting its function as a rigid support frame to prevent glue overflow. If the melting point of the third matrix resin is too high, it will affect the bonding effect and the integrity of the frame encapsulation glue, resulting in poor mechanical strength and bonding. Preferably, the melting point of the third matrix resin is 120-140°C, more preferably 125-135°C.

[0041] In principle, the choice of the third matrix resin is not limited, as long as it has a suitable melting point and has adhesive properties.

[0042] In some preferred embodiments, the third matrix resin is selected from at least one of polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). These materials can be controlled to a more suitable melting point and, due to their inherent hydrophobicity, improve the water barrier properties of the frame encapsulant.

[0043] Preferably, the polymer material is polyethylene (PE). Compared to other materials, PE has a more suitable melting point and can further improve the mechanical properties of the three-layer structure. It also avoids corrosion of the metal frame by the acidic segments and the impact of the hydrophilic segments on the water barrier properties of the encapsulant, further improving the water barrier properties of the frame encapsulant.

[0044] The amount of the third matrix resin is not limited. For example, the raw materials for forming the skeleton layer include 90wt%~100wt% of the third matrix resin, such as 90wt%, 91wt%, 92wt%, 93wt%, 94wt%, 95wt%, 96wt%, 97wt%, 98wt%, 99wt%, and 100wt%.

[0045] In some preferred embodiments, the raw materials of the skeleton layer also include an auxiliary agent to make up for the possible deficiencies of the third matrix resin. The selection of the auxiliary agent is not limited and can be appropriately selected based on considerations such as cross-linking, anti-oxidation, and light stability. For example, the auxiliary agent includes at least one of a cross-linking agent, a co-cross-linking agent, a silane coupling agent, an antioxidant, and a light stabilizer. Among them, the specific selection of the cross-linking agent, the co-cross-linking agent, the silane coupling agent, the antioxidant, and the light stabilizer can refer to the selection of the auxiliary agent in the above-mentioned frame adhesive layer.

[0046] The amount of the additive is not limited and can be added in an appropriate amount based on actual needs. For example, the raw materials for forming the skeleton layer include 0.01wt% to 10wt% of the additive, such as 0.01wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, and 10wt%.

[0047] In some preferred embodiments, the raw materials of the skeleton layer further include fillers to further enhance the supporting structural strength of the skeleton layer. For example, the filler may be at least one of fumed silica, carbon black, white carbon black, talc, mica, magnesium silicate, aluminum oxide, and calcium carbonate.

[0048] The amount of filler is not limited and can be added in an appropriate amount based on actual needs. For example, the skeleton layer includes 0.01wt% to 5wt% filler, such as 0.01wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, and 5wt%.

[0049] The thickness of the skeleton layer in the frame encapsulant is generally not limited, but an appropriate thickness ratio can balance the frame encapsulant's anti-overflow properties and its adhesion to the frame and photovoltaic modules. In some preferred embodiments, the skeleton layer's thickness accounts for 10% to 70% of the frame encapsulant's thickness; for example, it can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%.

[0050] Preferably, the thickness of the skeleton layer accounts for 10% to 60% of the thickness of the frame encapsulation glue; Further preferably, the thickness of the skeleton layer accounts for 20-40% of the thickness of the frame encapsulation glue.

[0051] For frame encapsulation glue In some preferred embodiments, the raw materials forming at least one of the frame adhesive layer, the skeleton layer, and the photovoltaic adhesive layer further include a pigment to provide a color for the frame encapsulant. The color is generally not limited and can be, for example, transparent, white, black, or a color.

[0052] Preferably, the pigment is selected from at least one of titanium dioxide, carbon black, azo pigments, phthalocyanine pigments, perylene pigments, isoindolinone pigments and quinacridone pigments.

[0053] More preferably, white or black pigment is used. White has a higher reflectivity and provides a power gain effect; black is used in photovoltaic modules used in black buildings to cover up the ugly effect.

[0054] Preferably, the raw material for forming the skeleton layer includes the pigment; and the pigment is arranged on the skeleton layer without affecting the bonding effect between the frame bonding layer and the photovoltaic bonding layer.

[0055] Second aspect Another object of the present invention is to provide a method for preparing the above-mentioned frame encapsulation glue, comprising the following steps: co-extruding the raw materials for forming the frame adhesive layer, the raw materials for forming the skeleton layer, and the raw materials for forming the photovoltaic adhesive layer by cast casting; or laminating the frame adhesive layer and the photovoltaic adhesive layer on the skeleton layer.

[0056] The frame encapsulation adhesive of the present application can be obtained by cast co-extrusion or lamination after selecting the appropriate material and gram weight, and the preparation method is simple.

[0057] The third aspect Another object of the present invention is to provide a frame-encapsulated photovoltaic module, including a photovoltaic module pre-pressed part, a frame, and the above-mentioned frame encapsulation glue.

[0058] Photovoltaic module pre-pressed parts The structure and materials are not limited and can be any photovoltaic module pre-pressing structure in the prior art. For example, the photovoltaic module pre-pressing parts include a glass plate, a photovoltaic film, and a battery cell group. The glass plate is used to bond with the photovoltaic adhesive layer in the frame encapsulation glue. In some embodiments, the photovoltaic film can also be bonded with the photovoltaic adhesive layer in the frame encapsulation glue. As a preferred embodiment of the present invention, the raw materials for forming the photovoltaic film include the raw materials for forming the photovoltaic adhesive layer, so that the frame encapsulation glue and the photovoltaic film are integrally formed. As a preferred embodiment of the present invention, the raw materials for forming the photovoltaic film include at least one of EVA, PE, POE or modified POE.

[0059] frame The material is not limited and can be any frame in the prior art. For example, it can be a metal frame, such as a zinc-magnesium-aluminum-steel frame, or a plastic frame.

[0060] Preferably, the bonding strength between the frame and the frame encapsulation adhesive is greater than 30 N / cm (under DH1000 test).

[0061] The structure of the frame is not limited, and for example, it can be an L-shaped frame, a Z-shaped frame, etc. As a preferred embodiment of the present invention, the frame is an L-shaped frame, which is connected to the side and bottom of the photovoltaic module respectively to improve the packaging effect.

[0062] As a preferred embodiment of the present invention, the frame-encapsulated photovoltaic module further includes a packaging tape, which is connected to the frame, the frame packaging adhesive, and the photovoltaic module to improve the packaging effect. The choice of packaging tape is not limited, and is preferably a material with good water-blocking properties, such as aluminum tape.

[0063] The fourth aspect Another object of the present invention is to provide a method for preparing the above-mentioned frame-encapsulated photovoltaic module, comprising the following steps: stacking the photovoltaic module pre-press, the frame encapsulation glue, and the frame in sequence, and then vacuum hot pressing them.

[0064] During the lamination process, the frame encapsulation glue is formed with the frame and photovoltaic module at one time, and there is no glue overflow. There is no need for secondary curing and no need to provide a moisture curing site, which improves production efficiency and reduces production costs.

[0065] The vacuum hot pressing conditions are not limited and can be consistent with the conditions used in conventional photovoltaic module molding. For example, the vacuum hot pressing temperature is 140-160°C, such as 140°C, 145°C, 150°C, 155°C, or 160°C; and the vacuum hot pressing time is 10-20 minutes, such as 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes, or 20 minutes.

[0066] Beneficial effects of the present invention: 1. The present application provides a frame encapsulation adhesive having a three-layer structure of a relatively low melting point and low fluidity photovoltaic adhesive layer + a relatively high melting point skeleton layer + a relatively low melting point and lower fluidity frame adhesive layer, which can prevent the adhesive from overflowing when used for frame encapsulation of photovoltaic modules.

[0067] In some preferred embodiments, the water-blocking performance and mechanical structure strength are improved by further controlling the first matrix resin of the photovoltaic adhesive layer to be POE, the second matrix resin of the frame adhesive layer to be POE, and the third matrix resin of the skeleton layer to be PE.

[0068] In some preferred embodiments, by further controlling the thickness ratio of the skeleton layer, the anti-overflow performance and the bonding performance of the frame encapsulation adhesive are effectively balanced, thereby improving the practicality of the frame encapsulation adhesive.

[0069] 2. The present application provides a method for preparing the above-mentioned frame encapsulation glue, which can be directly obtained by cast co-extrusion or lamination, and the preparation method is simple.

[0070] 3. The present application provides a photovoltaic module that uses the above-mentioned frame encapsulation glue for frame encapsulation. The encapsulated photovoltaic module has no glue overflow problem and thus has a regular appearance; in some preferred embodiments, it also has better water-blocking performance.

[0071] 4. The present application provides a method for preparing the above-mentioned frame-encapsulated photovoltaic module. The frame encapsulation glue can be integrally formed with the frame and photovoltaic module during the lamination process. There is no need for secondary curing molding and no need to provide a moisture curing site, which improves production efficiency and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 is a schematic structural diagram of the frame encapsulation adhesive in Example 1; Figure 2 is a schematic structural diagram of a frame-encapsulated photovoltaic module in Application Example 1; Figure 3 is a schematic structural diagram of a frame-encapsulated photovoltaic module in Application Example 2; In the figure: frame encapsulation glue 1, frame adhesive layer 11, skeleton layer 12, photovoltaic adhesive layer 13, photovoltaic module 2, frame 3. DETAILED DESCRIPTION

[0073] The following are specific embodiments of the present invention and further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0074] Example 1 A frame encapsulation adhesive, such as Figure 1 As shown, it includes, in sequence, a frame adhesive layer 11 for bonding with the frame, a skeleton layer 12, and a photovoltaic adhesive layer 13 for bonding with the photovoltaic module.

[0075] Among them, the frame adhesive layer 11 is formed by POE, which is Dow POE 8130 from the United States. The melt index at 190°C and 2.16kg load is 13g / 10min, and the melting point is 56°C; the ML value of the frame adhesive layer at 140°C is 1, and the pre-crosslinking degree is 0; the thickness of the frame adhesive layer is 200um.

[0076] The photovoltaic adhesive layer 13 is formed of POE, which is Dow POE 8411 from the United States. The melt index at 190°C and 2.16kg load is 18g / 10min, and the melting point is 76°C. The ML value of the photovoltaic adhesive layer at 140°C is 0.5, and the pre-crosslinking degree is 0. The thickness of the photovoltaic adhesive layer is 200um.

[0077] The skeleton layer 12 is formed of PE, which is white and has a melting point of 135° C. The skeleton layer has a thickness of 100 μm and accounts for 20% of the overall thickness of the frame encapsulation adhesive.

[0078] The frame encapsulation adhesive is prepared by the following steps: POE is extruded by an extruder for lamination, so that both sides of PE are respectively compounded with POE to prepare the frame encapsulation adhesive.

[0079] Example 2 A frame packaging adhesive sequentially comprises a frame bonding layer for bonding with a frame, a skeleton layer, and a photovoltaic bonding layer for bonding with a photovoltaic module.

[0080] The frame adhesive layer consists of 93wt% POE, 2wt% tert-butyl peroxyisopropyl carbonate as a crosslinker, 2wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, and 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer. The POE is Dow POE 8540, with a melt index of 1g / 10min and a melting point of 104°C at 190°C and a load of 2.16kg. The frame adhesive layer is obtained by mixing the components and then extruding them. The ML value of the frame adhesive layer at 140°C is 6.5, and the pre-crosslinking degree is 10%. The thickness of the frame adhesive layer is 200µm.

[0081] The photovoltaic adhesive layer consists of 95wt% POE, 1wt% tert-butyl isopropyl peroxycarbonate as a crosslinker, 1wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, and 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer. The POE is Dow POE 8540, with a melt index of 1g / 10min and a melting point of 104°C at 190°C and a load of 2.16kg. The photovoltaic adhesive layer is obtained by mixing the components and then extruding them. The ML value of the photovoltaic adhesive layer at 140°C is 6, and the pre-crosslinking degree is 5%. The thickness of the photovoltaic adhesive layer is 200μm.

[0082] The skeleton layer consists of 90wt% PE, 1wt% tert-butyl isopropyl peroxycarbonate as a crosslinker, 1wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer, 2wt% calcium carbonate as a filler, and 3wt% titanium dioxide as a pigment. PE has a melting point of 135°C. The skeleton layer is obtained by mixing all components and then extruding them. The skeleton layer is 100µm thick and accounts for 20% of the overall thickness of the frame encapsulant.

[0083] The frame encapsulation adhesive is prepared by the following steps: a frame adhesive layer, a skeleton layer, and a photovoltaic adhesive layer are co-extruded to obtain the frame encapsulation adhesive.

[0084] Example 3 This embodiment is basically the same as embodiment 2, with the only difference being that the first base resin of the frame adhesive layer is EVA.

[0085] The frame adhesive layer specifically comprises 93wt% EVA, 2wt% tert-butyl peroxyisopropyl carbonate as a crosslinker, 2wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, and 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer. The EVA is DuPont 11D625, with a melt index of 7.3g / 10min and a melting point of 94°C at 190°C and a load of 2.16kg. The frame adhesive layer is obtained by mixing the components and then extruding them. The ML value of the frame adhesive layer at 140°C is 7, and the pre-crosslinking degree is 10%. The thickness of the frame adhesive layer is 200µm.

[0086] Example 4 This embodiment is basically the same as the embodiment 2, with the only difference being that the first base resin of the frame adhesive layer is ethyl acrylate grafted POE, and the surface energy is 50.8 mN / m.

[0087] The frame adhesive layer specifically comprises 93wt% ethyl acrylate grafted poly(ethylene glycol) ether (POE), 2wt% tert-butyl peroxyisopropyl carbonate (crosslinking agent), 2wt% trimethylolpropane trimethacrylate (co-crosslinking agent), 2wt% γ-aminopropyltriethoxysilane (silane coupling agent), and 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate (light stabilizer). The ethyl acrylate grafted poly(ethylene glycol) ether (POE) has a melt index of 10g / 10min and a melting point of 70°C at 190°C and a load of 2.16kg. The frame adhesive layer is obtained by uniformly mixing the components and then extruding them. The ML value of the frame adhesive layer at 140°C is 6.8, and the pre-crosslinking degree is 10%. The thickness of the frame adhesive layer is 200µm.

[0088] Example 5 This embodiment is basically the same as embodiment 2, with the only difference being that the second matrix resin of the photovoltaic adhesive layer is EVA.

[0089] The photovoltaic adhesive layer specifically comprises 95wt% EVA, 1wt% tert-butyl isopropyl peroxycarbonate as a crosslinker, 1wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, and 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer. The EVA is DuPont 11D625, with a melt index of 7.3g / 10min and a melting point of 94°C at 190°C and a load of 2.16kg. The photovoltaic adhesive layer is obtained by mixing the components and then extruding them. The ML value of the photovoltaic adhesive layer at 140°C is 6.2, and the pre-crosslinking degree is 5%. The thickness of the photovoltaic adhesive layer is 200µm.

[0090] Example 6 This embodiment is basically the same as embodiment 2, with the only difference being that the third matrix resin of the skeleton layer is PP.

[0091] The skeleton layer specifically comprises 90wt% PP, 1wt% tert-butyl peroxyisopropyl carbonate as a crosslinker, 1wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer, 2wt% calcium carbonate as a filler, and 3wt% titanium dioxide as a pigment. The PP is a random copolymer with a melting point of 150°C. The skeleton layer is obtained by mixing the components and then extruding them. The skeleton layer is 100µm thick and accounts for 20% of the overall thickness of the frame encapsulant.

[0092] Example 7 This embodiment is basically the same as embodiment 2, and the only difference is that the thicknesses of the frame adhesive layer, the photovoltaic adhesive layer, and the skeleton layer are different.

[0093] The thickness of the frame adhesive layer is 225um; the thickness of the photovoltaic adhesive layer is 225um; the thickness of the skeleton layer is 50um; and the proportion of the skeleton layer to the overall thickness of the frame encapsulation glue is 10%.

[0094] Example 8 This embodiment is basically the same as embodiment 2, and the only difference is that the thicknesses of the frame adhesive layer, the photovoltaic adhesive layer, and the skeleton layer are different.

[0095] The thickness of the frame adhesive layer is 100um; the thickness of the photovoltaic adhesive layer is 100um; the thickness of the skeleton layer is 300um; and the proportion of the skeleton layer to the overall thickness of the frame encapsulation glue is 60%.

[0096] Example 9 This embodiment is basically the same as embodiment 2, and the only difference is that the thicknesses of the frame adhesive layer, the photovoltaic adhesive layer, and the skeleton layer are different.

[0097] The thickness of the frame adhesive layer is 150um; the thickness of the photovoltaic adhesive layer is 150um; the thickness of the skeleton layer is 200um; and the proportion of the skeleton layer to the overall thickness of the frame encapsulation glue is 40%.

[0098] Application Example 1 A frame-encapsulated photovoltaic module, such as Figure 2 As shown, it includes a photovoltaic component 2, a frame 3, and the frame packaging glue 1 prepared in Example 2.

[0099] The photovoltaic module 2 includes the first glass plate, POE film, battery group, POE film (the POE film, battery group, and POE film are shown as a whole in the figure) and the second glass plate in sequence; the frame 3 is an L-shaped zinc-magnesium-aluminum steel frame; and the frame encapsulation glue 1 is L-shaped. Figure 2 In the direction of , the vertical part of the frame 3, the vertical part of the frame encapsulation glue 1, and the side of the photovoltaic module 2 are connected in sequence, and the horizontal part of the frame 3, the horizontal part of the frame encapsulation glue 1, and the outer side of the second glass plate of the photovoltaic module 2 are connected in sequence.

[0100] This frame-encapsulated photovoltaic module is prepared by the following steps: After laminating the components of the photovoltaic module 2, the frame encapsulant 1, and the frame 3 in the above-described structure, the components were vacuum-heated at 145°C for 5 minutes and then maintained at 1 atmosphere for 12 minutes. Dimensional changes before and after lamination were measured.

[0101] Application Example 2 This application example is basically the same as application example 2, the only difference is that: Figure 3 As shown, it also includes packaging tape. In this application example, the packaging tape uses aluminum tape. Figure 3 In the direction of the frame, the vertical part of the aluminum tape is connected to the outer side of the frame 3, and the horizontal part is connected to the end face of the frame 3, the end face of the frame encapsulation glue 1, and the outer side of the first glass plate of the photovoltaic module 2 in sequence to further seal the end face of the frame encapsulation glue 1.

[0102] This frame-encapsulated photovoltaic module is prepared by the following steps: After the various components of the photovoltaic module 2, the frame encapsulation glue 1, and the frame 3 are stacked in sequence according to the above structure, vacuum heat is applied at 145°C for 5 minutes, and pressure is maintained for 12 minutes at a pressure of 1 atmosphere to obtain a packaging system; then, aluminum tape is used to perform a secondary packaging of the packaging system according to the above structure.

[0103] Comparative Example 1 This comparative example is basically the same as Example 2, the only difference being that it does not have a skeleton layer.

[0104] Specifically, the frame adhesive layer and the photovoltaic adhesive layer in Example 2 are co-extruded to obtain the frame encapsulation adhesive.

[0105] Comparative Example 2 This comparative example is substantially the same as Example 2, except that the melting point of the third matrix resin is not higher than the melting points of the first matrix resin and the second matrix resin.

[0106] Specifically, the skeleton layer is adjusted to include 90wt% PE, 1wt% tert-butyl isopropyl peroxycarbonate as a crosslinker, 1wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer, 2wt% calcium carbonate as a filler, and 3wt% titanium dioxide as a pigment. The PE used is Evolue SP0540 LLDPE with a melting point of 98°C. The skeleton layer is obtained by mixing all components and then extruding. The skeleton layer is 100µm thick and accounts for 20% of the overall thickness of the frame encapsulant.

[0107] Comparative Example 3 This comparative example is basically the same as Example 2, except that the ML value of the frame adhesive layer at 140° C. is lower than 0.15, and the ML value of the photovoltaic adhesive layer at the first temperature is lower than 0.10.

[0108] Specifically, the frame adhesive layer comprises 93wt% POE, 2wt% tert-butyl peroxyisopropyl carbonate as a crosslinker, 2wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, and 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer. The POE is LG Chem's LC-875-4c, which has a melt index of 33g / 10min and a melting point of 57°C at 190°C and a load of 2.16kg. The frame adhesive layer is obtained by mixing the components and then extruding them. The mixture has an ML value of 0.1 at 140°C.

[0109] The photovoltaic adhesive layer consists of 95wt% POE, 1wt% tert-butyl isopropyl peroxycarbonate as a crosslinker, 1wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, and 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer. The POE is LG Chem's LC-875-4c, which has a melt index of 33g / 10min and a melting point of 57°C at 190°C and a load of 2.16kg. The photovoltaic adhesive layer is obtained by mixing the components and extruding them. The mixture has an ML value of 0.08 at 140°C.

[0110] Comparative Example 4 This comparative example is basically the same as Example 2, except that the ML value of the photovoltaic adhesive layer is higher than the ML value of the frame adhesive layer.

[0111] Specifically, the frame adhesive layer comprises 95wt% POE, 1wt% tert-butyl peroxyisopropyl carbonate as a crosslinker, 1wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, and 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer. The POE is Dow POE 8540, with a melt index of 1g / 10min and a melting point of 104°C at 190°C and a load of 2.16kg. The frame adhesive layer is obtained by mixing the components and then extruding them. The ML value of the frame adhesive layer at 140°C is 6, and the pre-crosslinking degree is 5%. The thickness of the frame adhesive layer is 200µm.

[0112] The photovoltaic adhesive layer consists of 93wt% POE, 2wt% tert-butyl isopropyl peroxycarbonate as a crosslinker, 2wt% trimethylolpropane trimethacrylate as a co-crosslinker, 2wt% γ-aminopropyltriethoxysilane as a silane coupling agent, and 1wt% hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate as a light stabilizer. The POE is Dow POE 8540, with a melt index of 1g / 10min and a melting point of 104°C at 190°C and a load of 2.16kg. The photovoltaic adhesive layer is obtained by mixing the components and then extruding them. The ML value of the photovoltaic adhesive layer at 140°C is 6.5, and the pre-crosslinking degree is 10%. The thickness of the photovoltaic adhesive layer is 200µm.

[0113] Performance testing The performance of the frame encapsulation adhesives obtained in Examples 1 to 9 and Comparative Examples 1 to 4 was tested: Tensile strength: The force required to produce tensile deformation of the frame encapsulation adhesive at 120°C was tested. The test results are shown in Table 1 below.

[0114] Water vapor transmission rate: The water vapor transmission rate of the frame encapsulation glue was tested. The test results are shown in Table 1 below.

[0115] The frame encapsulant obtained in Examples 1 to 9 and Comparative Examples 1 to 4, and two layers of 250 μm transparent PET in the proofing mode were used to make photovoltaic modules according to the method in Application Example 1, and performance tests were performed: Glue overflow: Check whether the photovoltaic modules have glue overflow problems and measure the amount of glue overflow. The test results are shown in Table 1 below.

[0116] Adhesion performance: The adhesion strength (DH1000) between the frame encapsulation adhesive and the frame and photovoltaic module was tested. The test results are shown in Table 1 below.

[0117] Table 1. As shown in Table 1, by comparing the examples and the comparative examples, it can be seen that the frame encapsulation adhesive of the present application has suitable tensile strength and is not prone to overflow due to its three-layer structure of a relatively low melting point and low fluidity photovoltaic adhesive layer + a relatively high melting point skeleton layer + a relatively low melting point and lower fluidity frame adhesive layer.

[0118] Specifically: Comparing Example 2 and Comparative Example 1, Comparative Example 1 adopts a double-layer structure, lacks the support and restraint of the middle skeleton layer, and has problems such as insufficient mechanical strength and relatively high fluidity when used between the frame and the photovoltaic module, easy stretching between 75~120℃, severe thermal deformation, and easy glue overflow.

[0119] Comparing Example 2 and Comparative Example 2, although a skeleton layer is set in Comparative Example 2, the melting point of the third matrix resin of the skeleton layer is lower than the melting points of the second matrix resin of the photovoltaic bonding layer and the first matrix resin of the frame bonding layer. This makes the skeleton layer melt and flow before the photovoltaic bonding layer and the frame bonding layer during the hot pressing process, and the fluidity of the skeleton layer is not restricted, so it is easy to cause glue overflow; at the same time, after the photovoltaic bonding layer and the frame bonding layer melt and flow, they cannot be restrained by the skeleton layer, and further glue overflows; at the same time, there is still the problem of easy stretching and serious thermal deformation between 75~120℃.

[0120] Comparing Example 2 and Comparative Example 3, the photovoltaic adhesive layer and the frame adhesive layer in Comparative Example 3 have smaller ML values, higher fluidity, and lower molecular weight, making them easier to completely cross-link. This results in a higher degree of cross-linking of the adhesive film obtained after the photovoltaic adhesive layer and the frame adhesive layer are cured and formed, and the material loses its thermoplasticity. Although it can reduce the problem of glue overflow, it cannot be produced and processed to encapsulate frames and photovoltaic modules.

[0121] Comparing Example 2 and Comparative Example 4, the fluidity of the frame adhesive layer in Comparative Example 4 is greater than the fluidity of the photovoltaic adhesive layer, which makes the thermal expansion coefficients of the two and the frame and photovoltaic components mismatched, not only causing serious glue overflow, but also causing uneven thickness.

[0122] From the above, it can be seen that in the present application, at least: there is a three-layer structure with a skeleton layer, the photovoltaic bonding layer and the frame bonding layer have a lower melting point than the skeleton layer, the photovoltaic bonding layer and the frame bonding layer have low fluidity, and the fluidity of the frame bonding layer is lower than that of the photovoltaic bonding layer. This is an overall technical solution, which is indispensable for the frame encapsulation glue to achieve the bonding and packaging effect while solving the problem of glue overflow.

[0123] On the basis of solving the glue overflow problem, it can be seen from the comparison in the embodiment that by optimizing the raw materials and thickness of the bonding layer and the skeleton layer, a technical solution with better water barrier performance and bonding strength can be obtained.

[0124] Specifically: Comparing Example 1 and Example 2, in Example 2, the pre-crosslinking degree of the frame adhesive layer and the photovoltaic adhesive layer is increased by a crosslinking agent, a co-crosslinking agent, etc., which can increase the crosslinking network density of the frame encapsulation glue, thereby improving the adhesion and anti-aging performance. Comparing Example 2 with Examples 3 and 5, Examples 3 and 5 use EVA, which has a high water vapor permeability, resulting in poor water barrier performance of the frame encapsulation glue and poor performance in anti-aging. Comparing Example 2 with Example 6, Example 6 performs poorly in terms of water barrier, which may be due to the relatively poor tightness of PP, the poor compatibility of PP and POE, and the easy formation of discontinuous areas at the interface, which allows water vapor to penetrate. Comparing Example 2 with Examples 7, 8, and 9, it can be seen that a higher thickness ratio of the skeleton layer has a positive effect on the tensile properties of the frame encapsulation glue, and a higher thickness ratio of the frame adhesive layer and the photovoltaic adhesive layer has a positive effect on the adhesion of the frame encapsulation glue. When the skeleton layer thickness accounts for 20% to 40%, the frame encapsulation glue has both good anti-overflow glue and adhesion.

[0125] In summary, in this application, the frame encapsulation glue including a relatively low melting point and low fluidity pre-cross-linked photovoltaic adhesive layer of POE + a relatively high melting point skeleton layer of PE with a thickness of 20% to 40% + a relatively low melting point and lower fluidity pre-cross-linked frame adhesive layer including POE has good anti-overflow, water-blocking, and bonding properties.

[0126] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A frame encapsulation adhesive, comprising a frame adhesive layer for bonding to a frame and a photovoltaic adhesive layer for bonding to a photovoltaic module, characterized in that: The ML value of the frame adhesive layer at the first temperature is not less than 0.15; the raw material for forming the frame adhesive layer includes a first matrix resin; The ML value of the photovoltaic adhesive layer at the first temperature is not less than 0.10, and the ML value of the photovoltaic adhesive layer is lower than the ML value of the frame adhesive layer; the raw material for forming the photovoltaic adhesive layer includes a second matrix resin; The first temperature is not less than 140°C; The frame encapsulation glue further comprises a skeleton layer disposed between the frame adhesive layer and the photovoltaic adhesive layer; the raw material for forming the skeleton layer comprises a third matrix resin; The melting point of the first matrix resin is lower than that of the third matrix resin, and the melting point of the second matrix resin is lower than that of the third matrix resin.

2. The frame encapsulation adhesive according to claim 1, characterized in that: The first matrix resin has a melt index of less than 20 g / 10 min at 190° C. and a load of 2.16 kg; Preferably, the first matrix resin is selected from at least one of polyolefin resin and modified polyolefin resin; Preferably, the polyolefin resin is selected from at least one of EVA, PE, POE, and modified POE; Preferably, the side carbon of the modified polyolefin resin is an acrylate having 4 to 18 chain carbon atoms, and / or the surface energy of the modified polyolefin resin is 45 to 55 mN / m.

3. The frame encapsulation adhesive according to claim 1, characterized in that: The second matrix resin has a melt index of less than 20 g / 10 min at 190° C. and a load of 2.16 kg; Preferably, the second matrix resin is selected from at least one of EVA, PE, POE, and modified POE; Preferably, the second matrix resin is POE.

4. The frame encapsulation adhesive according to claim 1, characterized in that: The melting point of the third matrix resin is 110-150°C; Preferably, the third matrix resin is selected from at least one of PE, PP, and PET; Preferably, the third matrix resin is PE.

5. The frame encapsulation adhesive according to claim 1, characterized in that: The raw materials for forming the frame adhesive layer, the skeleton layer, and the photovoltaic adhesive layer independently further include auxiliary agents, and the auxiliary agents include at least one of a cross-linking agent, a co-cross-linking agent, a silane coupling agent, an antioxidant, and a light stabilizer.

6. The frame encapsulation adhesive according to claim 1, characterized in that: The pre-crosslinking degree of the frame adhesive layer is 0-30%, and / or the pre-crosslinking degree of the photovoltaic adhesive layer is 0-30%.

7. The frame encapsulation adhesive according to claim 1, characterized in that: The thickness of the skeleton layer accounts for 10% to 70% of the thickness of the frame encapsulation glue; Preferably, the thickness of the skeleton layer accounts for 10% to 60% of the thickness of the frame encapsulation glue; Preferably, the thickness of the skeleton layer accounts for 20-40% of the thickness of the frame encapsulation glue.

8. The frame encapsulation adhesive according to claim 1, characterized in that: The raw materials for forming at least one of the frame adhesive layer, the skeleton layer, and the photovoltaic adhesive layer further include pigments; Preferably, the pigment is selected from at least one of titanium dioxide, carbon black, azo pigments, phthalocyanine pigments, perylene pigments, isoindolinone pigments and quinacridone pigments.

9. A frame-encapsulated photovoltaic module, comprising a frame, a frame encapsulation adhesive, and a photovoltaic module pre-press, characterized in that: The frame encapsulation adhesive is the frame encapsulation adhesive according to any one of claims 1 to 8; Preferably, the bonding strength between the frame and the frame packaging adhesive is greater than 30 N / cm.

10. A method for preparing a frame-encapsulated photovoltaic module according to claim 9, characterized in that: The method comprises the following steps: stacking the photovoltaic component pre-press, the frame packaging glue and the frame in sequence, and then performing vacuum hot pressing to form the pre-pressed photovoltaic component.

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