Encapsulation adhesive film, method for preparing the same, and photovoltaic module

Abstract

The application relates to a packaging adhesive film and a preparation method thereof and a photovoltaic module. The packaging adhesive film comprises, in parts by mass, 100 parts of an adhesive film base and 12-18 parts of a modified mesoporous material; the modified mesoporous material comprises a mesoporous material and a modifier grafted on the mesoporous material, and the modifier comprises one or more of a crown ether and a polycyclic compound. A certain amount of the modified mesoporous material is added to the packaging adhesive film, the modifier in the modified mesoporous material comprises the crown ether and / or the polycyclic compound, the modifier is grafted on the surface of the mesoporous material, the unique ring structure can accurately match and identify Na + , and the capturing effect on Na + is strong. The specific surface area of the mesoporous material is large, a plurality of small pores exist, Na + captured after the modification agent can be adsorbed in the pores, and the migration of Na + under voltage is blocked, so that the anti-PID performance is improved.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and in particular to encapsulating films, their preparation methods, and photovoltaic modules. Background Technology

[0002] Photovoltaic modules consist of glass, encapsulant film, solar cells, backsheet, junction box, frame, silicone sealant, interconnect strips, etc. Among these, the encapsulant film protects the solar cells and improves the reliability of the module. During outdoor operation, modules are subjected to high temperature and humidity conditions, as well as high bias voltage in the module array, which can lead to power degradation, a phenomenon known as PID (potential-induced degradation).

[0003] Therefore, in order to reduce the risk of component PID failure, it is necessary to provide an adhesive film with good anti-PID properties. Summary of the Invention

[0004] Based on this, some embodiments of this application provide an encapsulating film and a method for preparing the same, which has improved anti-PID performance.

[0005] In addition, some other embodiments of this application also provide a photovoltaic module.

[0006] An encapsulating film, by weight, comprises: 100 parts of film substrate and 12 to 18 parts of modified mesoporous material;

[0007] The modified mesoporous material includes a mesoporous material and a modifier grafted onto the mesoporous material, wherein the modifier includes one or more crown ethers and polycyclic compounds.

[0008] In some embodiments, the raw materials for preparing the modified mesoporous material include a mesoporous material, a modifier, and a silane coupling agent. The mesoporous material has silanol groups, the modifier contains reactive groups, and the silane coupling agent has the general structural formula: X-(CH2). n -Si(OR)3, where X is an organic functional group and OR is a hydrolyzable group, and the X group in the silane coupling agent can react with the reactive group in the modifier.

[0009] In some embodiments, the modified mesoporous material satisfies one or more of the following conditions:

[0010] (1) The mass ratio of the modifier to the mesoporous material is 1:(5~10);

[0011] (2) The reactive groups include one or more of amino, hydroxyl, carboxyl and thiol groups;

[0012] (3) The X group includes one or more of amino, epoxy, mercapto and alkenyl groups;

[0013] (4) The molar ratio of the silane coupling agent to the modifier is (1~1.2):1.

[0014] In some embodiments, the silane coupling agent includes one or more of aminopropyltriethoxysilane, epoxypropoxytrimethoxysilane, mercaptopropyltrimethoxysilane, and vinyltriethoxysilane; and / or,

[0015] The modifier includes one or more of amino-modified crown ethers, amino-modified calixarenes, hydroxyl-modified calixarenes, cyclodextrins, and azacrown ethers.

[0016] In some embodiments, the modifier includes one or more of amino-modified 18-crown-6, amino-modified 15-crown-5, amino-modified 12-crown-4, amino-modified dibenzo-18-crown-6, amino-modified calix[4]arene, hydroxyl-modified calix[4]arene, cyclodextrin, and azacrown ether.

[0017] In some embodiments, the mesoporous material satisfies one or more of the following conditions:

[0018] (1) The mesoporous material includes one or more of mesoporous silica and mesoporous molecular sieve; optionally, the mesoporous material includes one or more of SBA-15, MCM-41 and STMS;

[0019] (2) The specific surface area of ​​the mesoporous material is 500 m². 2 / g~1000m 2 / g;

[0020] (3) The pore size of the mesoporous material is 2nm~10nm.

[0021] In some embodiments, the encapsulating film further includes 1 to 2 parts of a UV light absorber, optionally, the UV light absorber being loaded within the pores of the modified mesoporous material; and / or,

[0022] The film substrate includes one or more of EVA, POE, and EPE; and / or,

[0023] The encapsulating film further includes one or more of the following: 1 to 3 parts crosslinking agent, 2 to 3 parts crosslinking aid, 1 to 3 parts coupling agent, and 1 to 3 parts filler.

[0024] A method for preparing an encapsulating film, comprising the following steps:

[0025] By weight, 100 parts of the adhesive film matrix and 12 to 18 parts of the modified mesoporous material are mixed and extruded into a film to prepare an encapsulating adhesive film.

[0026] The modified mesoporous material includes a mesoporous material and a modifier grafted onto the mesoporous material, wherein the modifier includes one or more crown ethers and polycyclic compounds.

[0027] In some embodiments, the modified mesoporous material is prepared by the following method:

[0028] The modifier, the mesoporous material, and at least partially hydrolyzed silane coupling agent are mixed and reacted under a protective atmosphere at 50°C to 70°C for 4 to 12 hours to obtain the modified mesoporous material.

[0029] In some embodiments, prior to the step of mixing the modifier, the mesoporous material, and the at least partially hydrolyzed silane coupling agent, the method further includes: vacuum drying the mesoporous material at 100°C to 150°C for 2 to 4 hours; and / or,

[0030] The at least partially hydrolyzed silane coupling agent is obtained by dissolving the silane coupling agent in an organic solvent and then mixing it with water for 0.5 h to 1 h, wherein the molar ratio of water to the silane coupling agent is 1:(1~2).

[0031] A photovoltaic module includes a solar cell and an encapsulation structure, the encapsulation structure being used to encapsulate the solar cell, the encapsulation structure including the encapsulating film described above or including an encapsulating film prepared by the preparation method described above.

[0032] In some embodiments, the solar cell includes a back-contact solar cell; and / or,

[0033] The encapsulation structure also includes glass, the encapsulation film is disposed on both sides of the solar cell, and the glass is disposed on the side of the encapsulation film away from the solar cell.

[0034] Studies have shown that Na + Migration is a major cause of PID failure in photovoltaic modules. Based on this, some embodiments of this application provide an encapsulating film in which a certain amount of modified mesoporous material is added to the film matrix. The modifier in the modified mesoporous material includes crown ethers and / or polycyclic compounds, which are grafted onto the surface of the mesoporous material. The cyclic structure of the modifier can accurately match and recognize Na+. + , to Na + The trapping effect is strong. Mesoporous materials have a large specific surface area and contain multiple micropores, which can trap Na after the modifier. + It adsorbs in the pores, preventing its migration under voltage, thereby improving anti-PID performance. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of a process flow for preparing modified mesoporous materials according to some embodiments of this application. Detailed Implementation

[0037] To facilitate understanding of this application, a more comprehensive description of the application will be provided below in conjunction with specific embodiments. Preferred embodiments of the application are given in the specific embodiments. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] Unless otherwise stated or in case of conflict, the terms or phrases used in this application shall have the following meanings:

[0040] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include at least one of those features.

[0041] In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise expressly and specifically limited.

[0042] In this application, "one or more" refers to any one, two, or more of the listed items. "Multiple" refers to any two or more of the listed items.

[0043] Unless otherwise specified, all percentage concentrations mentioned in this application refer to the final concentration. The final concentration refers to the proportion of the added component in the system after the addition of that component.

[0044] In this application, terms such as "further," "even more," "particularly," "for example," "like," "example," and "exemplary" are used for descriptive purposes to indicate a connection in the coverage of different technical solutions presented earlier and later, but should not be construed as limiting the preceding technical solution or restricting the scope of protection herein. Unless otherwise specified herein, A (e.g., B) indicates that B is a non-limiting example of A, and it can be understood that A is not limited to B.

[0045] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it is selected from either "present" or "absent." If multiple "options" appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "option" is independent. In this application, descriptions such as "optionally contains" and "optionally includes" indicate "contains or does not contain." "Optional component X" indicates whether component X exists or does not exist, or whether component X is contained or not.

[0046] When a numerical range is disclosed in this application, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed in this application should be understood to include any and all subranges to which they are included.

[0047] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0048] The terms "comprising" and "having," and any variations thereof, used in the embodiments of this application, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or components inherent to such processes, methods, products, or devices.

[0049] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0050] In the flowchart of this application, although the steps are shown sequentially according to the arrows, these steps are not necessarily performed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps. They can be executed in other orders. Moreover, at least some of the steps in the diagram may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times. Their execution order is not necessarily sequential, but can be performed alternately or in turn with at least some of other steps or other sub-steps or stages.

[0051] PID is mainly caused by high temperature, high humidity, and system bias. Currently, the PID effect is classified into three types: PID-s (shunting), PID-p (polarization), and PID-c (corrosion). Among them, PID-s is mainly caused by Na... + The migration from the glass to the solar cell causes current shunting at the PN junction, which manifests as a shunt resistance (R). sh The decrease in fill factor (FF) and PID-p is due to the positive charge (Na) in the dielectric / passivation layer. + The accumulation of negative charges leads to a high degree of surface recombination, affecting the performance of the PN junction and resulting in a faster overall degradation rate. However, the performance loss is fully recoverable. PID-c is often caused by environmental aging of materials such as adhesive films and sealants. x O y Silicon nitride (Si) x The Na layer and metal components suffered irreversible damage due to electrochemical corrosion. Therefore, Na... + Migration is the main cause of PID failure in photovoltaic modules.

[0052] Based on this, the first aspect of this application provides an encapsulating film, comprising, by weight parts: 100 parts of film substrate and 12 to 18 parts of modified mesoporous material;

[0053] Modified mesoporous materials include mesoporous materials and modifiers grafted onto the mesoporous materials. Modifiers include one or more of crown ethers and polycyclic compounds.

[0054] Some embodiments of this application provide an encapsulating film in which a certain amount of modified mesoporous material is added to the film matrix. The modifier in the modified mesoporous material includes crown ethers and / or polycyclic compounds, which are grafted onto the surface of the mesoporous material. The unique cyclic structure can accurately match and recognize Na. + , to Na + The trapping effect is strong. Mesoporous materials have a large specific surface area and contain multiple micropores, which can trap Na after the modifier. +Adsorbed in the pores, it prevents Na from migrating under voltage. + This improves the anti-PID performance.

[0055] Furthermore, adding a certain amount of the aforementioned modified mesoporous material to the encapsulating film has minimal impact on the film's mechanical and optical properties. Specifically, if the amount of modified mesoporous material in the encapsulating film is too small, there will be insufficient adsorption sites for sodium ions, resulting in substandard anti-PID performance. If the amount of modified mesoporous material is too large, it may lead to decreased flexibility and increased brittleness of the encapsulating film, affecting its processing performance.

[0056] In some embodiments of this application, mesoporous materials and modifiers are added to the encapsulating film, and the two are grafted together. This allows the modifier to accurately recognize sodium ions, and the mesoporous material to fix the sodium ions recognized by the modifier in its pores, thereby significantly improving the anti-PID performance. However, if only mesoporous materials or crown ethers are added to the encapsulating film, although the mesoporous material fixes sodium ions in its pores, its ability to capture sodium ions is weak, resulting in insufficient anti-PID performance. While crown ethers can capture sodium ions, they are difficult to fix, and the problem of sodium ion migration still exists, resulting in insufficient anti-PID performance. This application achieves this by covalently grafting and hybridizing the inorganic framework of the mesoporous material with the modifier (such as crown ethers or polycyclic compounds), thus achieving a significant improvement in anti-PID performance. + ")" and "fixed (mesoporous material confined retention of Na)" + ")" is coupled to the same particle and its encapsulating film is placed on the side close to the glass. At a high total dosage, it maintains low migration, low haze and stable cross-linking / adhesion, achieving synergistic effect without side effects.

[0057] In some embodiments, the mass ratio of the modifier to the mesoporous material is 1:(5~10). For example, the mass ratio of the modifier to the mesoporous material may be, but is not limited to, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, or any range of these values. Using the above setting is beneficial for further improving the anti-PID effect. If the amount of modifier is too large, it may cause the modifier to excessively accumulate on the surface of the mesoporous material, clogging the pores and reducing the resistance to Na+. + This reduces the adsorption capacity and rate, while increasing cost and potentially affecting the transparency and mechanical properties of the film. If the modifier dosage is too low, insufficient coverage of the mesoporous surface will negatively impact the adsorption of Na+. + Its identification and capture capabilities are weak, and its anti-PID effect is insufficient.

[0058] In this application, mesoporous materials refer to a class of porous materials with an average pore size between 2nm and 50nm, such as 2nm to 10nm, which have characteristics such as extremely high specific surface area, regular and ordered pore structure, narrow pore size distribution, and continuously adjustable pore size.

[0059] In some embodiments, the mesoporous material includes a silicon-based mesoporous material. Specifically, the mesoporous material includes one or more of mesoporous silica and mesoporous molecular sieves. In some embodiments, the mesoporous material includes one or more of SBA-15, MCM-41, and STMS (star-shaped mesoporous silica).

[0060] In some embodiments, the specific surface area of ​​the mesoporous material is 500 m². 2 / g~1000 m 2 / g. Mesoporous materials have a large specific surface area.

[0061] In some embodiments, the specific surface area of ​​SBA-15 is 600 m². 2 / g ~900m 2 / g. The specific surface area of ​​MCM-41 is 800 m². 2 / g~1000 m 2 / g. The specific surface area of ​​STMS is 500 m². 2 / g ~800 m 2 / g.

[0062] In some embodiments, the average pore size of the mesoporous material is 2 nm to 10 nm. Specifically, the average pore size of MCM-41 is 2 nm to 3 nm (uniform pores). The average pore size of SBA-15 is 5 nm to 10 nm. SBA-15 has a larger pore size, making it easier to load UV absorbers. The average pore size of STMS is 3-6 nm. STMS has a star-shaped structure and a large pore volume.

[0063] In some embodiments, a crown ether refers to a macrocyclic polyether containing multiple -oxy-methylene-structural units in its molecule. The carbon atom in the crown ether may also be substituted with a heteroatom such as a nitrogen atom, and it may be called a azeotropic crown ether. In some embodiments, the crown ether includes one or more of unsubstituted or nitrogen-substituted 18-crown-6, unsubstituted or nitrogen-substituted 15-crown-5, unsubstituted or nitrogen-substituted 12-crown-4, and unsubstituted or nitrogen-substituted dibenzo-18-crown-6.

[0064] In some embodiments, polycyclic compounds refer to macrocyclic compounds having a polycyclic structure, which can be used in Na + Identification. Specifically, polycyclic compounds include one or more of calixarenes and cyclodextrins. Calcineurins, for example, calix[4]arenes, can have reactive groups introduced by sulfonation or amino modification. Cyclodextrins (such as β-cyclodextrin) have multiple reactive hydroxyl groups.

[0065] In some embodiments, the raw materials for preparing the modified mesoporous material include a mesoporous material, a modifier, and a silane coupling agent. The mesoporous material has silanol groups, the modifier contains reactive groups, and the general structural formula of the silane coupling agent is: X-(CH2). n -Si(OR)3, where X is an organic functional group and OR is a hydrolyzable group, the X group in the silane coupling agent can react with the reactive group in the modifier. Mesoporous materials possess silanols, which can undergo condensation reactions with the hydrolysis products of the silane coupling agent (such as silanols) to form stable Si-O-Si covalent bonds. The X group in the silane coupling agent reacts with the reactive group in the modifier, using the silane coupling agent to graft the modifier onto the mesoporous material. One end of the silane coupling agent is connected to the mesoporous material, and the other end is connected to the modifier.

[0066] Specifically, the modified mesoporous material is prepared through the following steps:

[0067] The modifier, mesoporous material, and at least partially hydrolyzed silane coupling agent are mixed and reacted under a protective atmosphere at 50°C to 70°C for 4 to 12 hours to obtain the modified mesoporous material.

[0068] Specifically, the above-mentioned reaction temperature and time conditions are advantageous for increasing the reaction rate while reducing side reactions. Specifically, excessively high reaction temperatures may lead to the decomposition of silane coupling agents or the degradation of crown ethers, while excessively low temperatures result in a slow reaction rate. Too short a reaction time may lead to incomplete reactions, while too long a reaction time may lead to side reactions or aggregation.

[0069] In some embodiments, the process further includes: activating the mesoporous material. Specifically, the mesoporous material is vacuum dried at 100°C to 150°C for 2 to 4 hours. This activation treatment removes surface-adsorbed water, activates silanol groups (-SiOH), and increases the density of silanol groups on the surface of the mesoporous material.

[0070] In some embodiments, the at least partially hydrolyzed silane coupling agent is obtained by dissolving the silane coupling agent in an organic solvent and then mixing it with water for 0.5 h to 1 h, wherein the molar ratio of water to silane coupling agent is 1:(1 to 2).

[0071] Specifically, the silane coupling agent is dissolved in anhydrous ethanol. The volume ratio of solvent to silane coupling agent is 10:1. It should be understood that the above is only one relatively specific dissolution method, but it is not a limitation; any method that can dissolve the silane coupling agent is acceptable.

[0072] In some embodiments, after the reaction is complete, the process further includes: solid-liquid separation of the reaction system, and washing and drying of the solid product. Specifically, solid-liquid separation is performed by centrifugation or filtration. In the washing step, ethanol is used for washing. In the drying step, vacuum drying is carried out at 60°C to 80°C for 4 to 8 hours.

[0073] In some embodiments, please refer to Figure 1 The preparation method of modified mesoporous materials includes the following steps:

[0074] Step S110: Vacuum dry the mesoporous material at 100℃~150℃ for 2h~4h.

[0075] Step S120: Dissolve the silane coupling agent in an organic solvent, then mix it with water and react for 0.5h~1h to obtain at least partially hydrolyzed silane coupling agent. The molar ratio of water to silane coupling agent is 1:(1~2).

[0076] Step S130: Mix the modifier, mesoporous material and at least partially hydrolyzed silane coupling agent, and react them under a protective atmosphere at 50℃~70℃ for 4h~12h to obtain the modified mesoporous material. The mass ratio of the modifier to the mesoporous material is 1:(5~10), and the molar ratio of the modifier to the silane coupling agent is 1:(1~1.2).

[0077] In some embodiments, the molar ratio of silane coupling agent to modifier is (1~1.2):1. This setting helps ensure complete reaction and further improves the anti-PID effect. If the amount of silane coupling agent is too large, it may cause self-polymerization of the coupling agent, forming a gel that covers the mesoporous surface, affecting the grafting of the modifier and the pore structure of the mesoporous material. If the amount of silane coupling agent is too small, the grafting rate of the modifier is low, and the modification effect is insufficient.

[0078] In some embodiments, the general molecular formula of the silane coupling agent is: X-(CH2) n -Si(OR)3, where X is an organic functional group and OR is a hydrolyzable group. Specifically, R is a C1-C3 alkyl group. Specifically, OR is a methoxy or ethoxy group.

[0079] Specifically, X includes one or more of amino, epoxy, mercapto, isocyanate, and alkenyl groups. X is -NH2 and can react with hydroxyl, carboxyl, or epoxy groups in the modifier. X is epoxy and can react with amino, hydroxyl, or mercapto groups in the modifier. X is -SH and can react with alkenyl or epoxy groups in the modifier. X is alkenyl and can react with mercapto groups in the modifier. X is isocyanate and can react with amino groups in the modifier.

[0080] In some embodiments, the silane coupling agent includes one or more of KH550 (aminopropyltriethoxysilane), KH560 (epoxypropoxytrimethoxysilane), KH590 (mercaptopropyltrimethoxysilane), and vinyltriethoxysilane.

[0081] In some embodiments, the modifier has a group that can react with the organic functional group of the silane coupling agent. Specifically, the reactive group includes one or more of amino (-NH2), hydroxyl (-OH), carboxyl (-COOH), epoxy, and mercapto (-SH).

[0082] Specifically, the modifiers include one or more of amino-modified crown ethers, amino-modified calixarenes, hydroxyl-modified calixarenes, cyclodextrins, and azacrown ethers. Specifically, the modifiers include one or more of amino-modified 18-crown-6, amino-modified 15-crown-5, amino-modified 12-crown-4, amino-modified dibenzo-18-crown-6, amino-modified calix[4]arenes, hydroxyl-modified calix[4]arenes, cyclodextrins, and azacrown ethers. All of the above modifiers have groups that can react with silane coupling agents and exhibit good selectivity for sodium ions.

[0083] Mesoporous materials contain silanol groups (-SiOH) on their surface. These groups can undergo condensation reactions with the hydrolysis products of silane coupling agents (such as silanols) to form stable Si-O-Si covalent bonds. Therefore, mesoporous materials do not require additional modification, but the density of surface silanol groups can be further increased through activation treatment.

[0084] In some embodiments, the film substrate includes one or more of EVA, POE, and EPE. In some embodiments, the film substrate includes EVA. The volume resistivity relationship of the films is as follows: POE > EPE > EVA, and the higher the volume resistivity, the higher the Na... + The better the barrier effect, the higher the risk of PID in the EVA film. Including EVA in the film matrix is ​​beneficial to improving its anti-PID performance. It is understood that in other embodiments, the film matrix may also be POE or EPE, and the modified mesoporous material of this application can be added thereto, which can also improve the anti-PID performance compared to the film without the added modified mesoporous material.

[0085] In some embodiments, in the encapsulating film, the mass fraction of the film substrate is 100 parts, and the mass fraction of the modified mesoporous material may be, but is not limited to, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, or any combination of these values.

[0086] In some embodiments, the encapsulating film further includes 1 to 2 parts of a UV light absorber. Specifically, the UV light absorber includes one or more of benzotriazole and hindered amines. Adding a UV light absorber to the film matrix is ​​beneficial for improving the UV resistance of the encapsulating film. However, in conventional methods, after adding a UV light absorber, there is a problem that the UV absorber migrates in the film, leading to UV failure. With the encapsulating film of some embodiments of this application, the UV absorber can be fixed in the pores of the modified mesoporous material, reducing the risk of migration and failure. This allows the encapsulating film to have both good anti-PID performance and good UV resistance.

[0087] In some embodiments, the encapsulating film further includes one or more of the following: 1 to 3 parts of crosslinking agent, 2 to 3 parts of crosslinking aid, 1 to 3 parts of coupling agent, and 1 to 3 parts of filler.

[0088] Specifically, the crosslinking agent includes one or more of dicumyl peroxide (DCP), tert-butyl peroxycarbonate-2-ethylhexyl (TBEC), and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (DBPH). The crosslinking aid includes one or more of triallyl cyanurate (TAIC) and acrylate monomers. The coupling agent includes one or more of KH550, KH560, and KH590. The filler includes one or more of SiO2, CaCO3, and Al2O3.

[0089] In some embodiments, the encapsulating film comprises, by weight, 100 parts of film matrix, 12 to 18 parts of modified mesoporous material, 1 to 2 parts of UV light absorber, 1 to 3 parts of crosslinking agent, 2 to 3 parts of crosslinking aid, 1 to 3 parts of coupling agent, and 1 to 3 parts of filler.

[0090] In some embodiments, the thickness of the encapsulating film is 300μm to 600μm.

[0091] The second aspect of this application provides a method for preparing an encapsulating film, comprising the following steps:

[0092] By weight, 100 parts of the adhesive film matrix and 12 to 18 parts of the modified mesoporous material are mixed and extruded into a film to prepare an encapsulating adhesive film.

[0093] The modified mesoporous material includes a mesoporous material and a modifier grafted onto the mesoporous material. The modifier includes one or more crown ethers and polycyclic compounds.

[0094] Specifically, the modified mesoporous materials and their preparation are the same as those described in the first aspect above, and will not be repeated here.

[0095] Specifically, the extrusion film formation step is not particularly limited and can be any commonly used method in the field.

[0096] A third aspect of this application provides a photovoltaic module, including a solar cell and an encapsulation structure. The encapsulation structure is used to encapsulate the solar cell and includes the encapsulation film of the first aspect or the encapsulation film prepared by the preparation method of the second aspect.

[0097] In some embodiments, the encapsulation structure further includes glass, with the encapsulating film disposed on both sides of the solar cell, and the glass disposed on the side of the encapsulating film away from the solar cell. It is understood that in other embodiments, the encapsulation structure may also include a backplate disposed on the side of the encapsulating film away from the solar cell.

[0098] In some embodiments, the encapsulating film of this application is disposed between the glass and the solar cell. The encapsulating film between the solar cell and the backsheet can be the encapsulating film of this application, or a conventional encapsulating film.

[0099] In some embodiments, the solar cell includes a back-contact solar cell.

[0100] Back-contact (BC) cells are a novel battery technology where both the positive and negative electrodes are located on the back of the cell, leaving the front unobstructed and significantly improving photoelectric conversion efficiency. The positive and negative electrodes consist of fine grid lines for collecting current and pads (PADs) for interconnecting the cells. The grid lines are arranged in an interdigitated pattern, and the PADs are divided into positive and negative terminals. The positive PAD is connected to the positive grid lines, and the negative PAD is connected to the negative grid lines. During the cell-to-module interconnection process, solder ribbons are bonded to the PADs, and the ribbons are then bonded to busbars for current transmission.

[0101] The unique cell structure of BC modules, with the PN junction located on the back of the cell, makes the risk of PID-s (Potential Ingress and Degradation) greater for double-glass modules. However, encapsulation using the encapsulating film of some embodiments of this application helps reduce the risk of PID failure in BC double-glass modules and blocks Na... + The migration.

[0102] It is understood that in other embodiments, the solar cell is not limited to a back-contact solar cell, but may also be other commonly used solar cells.

[0103] To make the objectives and advantages of this application clearer, the encapsulating film and its effects are further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining this application and should not be used to limit this application. Unless otherwise specified, the following embodiments do not include components other than unavoidable impurities. Unless otherwise specified, the drugs and instruments used in the embodiments are conventional choices in the art. Experimental methods in the embodiments that do not specify specific conditions are implemented according to conventional conditions, such as those described in literature, books, or methods recommended by the manufacturer.

[0104] Example 1

[0105] This embodiment provides an encapsulating film, comprising, by weight parts: 100 parts EVA particles, 16 parts modified mesoporous material, 1 part UV light absorber, 1 part crosslinking agent, 2 parts crosslinking aid, 2 parts coupling agent, and 2 parts filler. The modified mesoporous material is amino-modified 18-crown-6 modified SBA15. The UV light absorber is benzotriazole, the crosslinking agent is DCP, the crosslinking aid is TAIC, the coupling agent is KH550, and the filler is SiO2. The preparation method is as follows: The components are mixed according to the above proportions and extruded into a film to obtain an encapsulating film with a thickness of 450 μm.

[0106] The preparation method of modified mesoporous materials is as follows:

[0107] (1) The mesoporous material, silane coupling agent and modifier are prepared according to the following ratio: the mass ratio of mesoporous material SBA15 and amino-modified 18-crown-6 modifier is 10:1, and the molar ratio of silane coupling agent to modifier is 1.1:1.

[0108] (2) The mesoporous material was vacuum dried at 120°C for 3 hours to remove surface adsorbed water and activate silanol groups (-SiOH).

[0109] (3) Dissolve the silane coupling agent in anhydrous ethanol (the volume ratio of solvent to silane coupling agent is about 10:1), add a small amount of deionized water (the molar ratio of water to silane coupling agent is 1.5:1), and stir at room temperature for 0.5 hours to partially hydrolyze the silane coupling agent.

[0110] (4) The dried mesoporous material was added to the above hydrolysate, and then amino-modified 18-crown-6 was added. The mixture was stirred at 60°C for 8 hours under nitrogen protection. After the reaction, the solid product was collected by centrifugation or filtration and washed repeatedly with ethanol to remove unreacted substances. Finally, the product was vacuum dried at 70°C for 6 hours to obtain the modified mesoporous material.

[0111] Example 2

[0112] This embodiment provides an encapsulating film, which is similar to the encapsulating film in Example 1, except that the modified mesoporous material is different. The modified mesoporous material in this embodiment is hydroxyl-modified calixarene-modified MCM-41[4].

[0113] The preparation method of the modified mesoporous material in this embodiment is as follows:

[0114] (1) The mesoporous material, silane coupling agent and modifier are prepared according to the following ratio: the mass ratio of mesoporous material MCM-41 and hydroxyl-modified calixarene modifier is 5:1, and the molar ratio of silane coupling agent to modifier is 1.2:1.

[0115] (2) The mesoporous material was vacuum dried at 100°C for 4 hours to remove surface adsorbed water and activate silanol groups (-SiOH).

[0116] (3) Dissolve the silane coupling agent in toluene (the volume ratio of solvent to silane coupling agent is about 10:1), add a small amount of deionized water (the molar ratio of water to silane coupling agent is 1:1), and stir at room temperature for 0.5 hours to partially hydrolyze the silane coupling agent.

[0117] (4) The dried mesoporous material was added to the above hydrolysate, and then hydroxyl-modified calix[4]arene was added. The mixture was stirred at 50°C for 12 hours under nitrogen protection. After the reaction, the solid product was collected by centrifugation or filtration and washed with ethanol several times to remove unreacted substances. Finally, the product was vacuum dried at 60°C for 8 hours to obtain the modified mesoporous material.

[0118] Example 3

[0119] This embodiment provides an encapsulating film similar to the encapsulating film in Embodiment 1, except that the modified mesoporous material is different. The modified mesoporous material in this embodiment is cyclodextrin-modified STMS.

[0120] The preparation method of the modified mesoporous material in this embodiment is as follows:

[0121] (1) The mesoporous material, silane coupling agent and modifier are prepared according to the following ratio: the mass ratio of mesoporous material STMS and modifier cyclodextrin is 8:1, and the molar ratio of silane coupling agent to modifier is 1.2:1.

[0122] (2) The mesoporous material was vacuum dried at 150°C for 2 hours to remove surface adsorbed water and activate silanol groups (-SiOH).

[0123] (3) Dissolve the silane coupling agent in anhydrous ethanol (the volume ratio of solvent to silane coupling agent is about 10:1), add a small amount of deionized water (the molar ratio of water to silane coupling agent is 2:1), and stir at room temperature for 1 hour to partially hydrolyze the silane coupling agent.

[0124] (4) Add the dried mesoporous material to the above hydrolysate, then add cyclodextrin, and stir the mixture at 70°C for 4 hours under nitrogen protection. After the reaction, collect the solid product by centrifugation or filtration, and wash it repeatedly with ethanol to remove unreacted substances. Finally, dry it under vacuum at 80°C for 4 hours to obtain the modified mesoporous material.

[0125] Example 4

[0126] This embodiment provides an encapsulating film similar to the encapsulating film of Example 1, except that the mass ratio of the modifier to the mesoporous material is different in the preparation of the modified mesoporous material. In this embodiment, the mass ratio of the modifier to the mesoporous material is 1:12.

[0127] Example 5

[0128] This embodiment provides an encapsulating film similar to the encapsulating film of Embodiment 1, except that the mass ratio of the modifier to the mesoporous material is different in the preparation of the modified mesoporous material. In this embodiment, the mass ratio of the modifier to the mesoporous material is 1:2.

[0129] Example 6

[0130] This embodiment provides an encapsulating film, which is similar to the encapsulating film in Embodiment 1, except that the mesoporous material is not activated during the preparation of the modified mesoporous material.

[0131] Comparative Example 1

[0132] Comparative Example 1 provides an encapsulating film, which is a conventional POE film. Specifically, by weight, it comprises: 100 parts of POE film matrix, 1 part of UV light absorber, 1 part of crosslinking agent, 2 parts of crosslinking aid, 2 parts of coupling agent, and 2 parts of filler. The UV light absorber is benzotriazole, the crosslinking agent is DCP, the crosslinking aid is TAIC, the coupling agent is KH550, and the filler is SiO2.

[0133] Comparative Example 2

[0134] Comparative Example 2 provides an encapsulating film similar to that of Example 1, except that the modified mesoporous material in Example 1 is replaced with an unmodified mesoporous material.

[0135] Comparative Example 3

[0136] Comparative Example 3 provides an encapsulating film similar to that of Example 1, except that a mixture of crown ether and mesoporous material SBA15 at a mass ratio of 1:10 is used to replace the modified mesoporous material in Example 1. Specifically, the encapsulating film of Comparative Example 3 comprises: 100 parts of EVA particles, 16 parts of modified mesoporous material, 1 part of UV light absorber, 1 part of crosslinking agent, 2 parts of crosslinking aid, 2 parts of coupling agent, and 2 parts of filler. The UV light absorber is benzotriazole, the crosslinking agent is DCP, the crosslinking aid is TAIC, the coupling agent is KH550, and the filler is SiO2.

[0137] Comparative Example 4

[0138] A comparative example provides an encapsulating film similar to that of Example 1, except that the mass fraction of the modified mesoporous material is different. In Comparative Example 4, the mass fraction of the modified mesoporous material is 5 parts.

[0139] The initial tack, volume resistivity, and thermal aging / yellowing stability of the encapsulating films in the above embodiments and comparative examples were tested. The encapsulating films were then used to fabricate photovoltaic modules, and the PID288 performance of the photovoltaic modules was tested. The test results are shown in Table 1 below.

[0140] The testing method is as follows:

[0141] (1) Initial adhesion test of encapsulating film to glass: At 25℃, the initial adhesion of encapsulating film to glass is tested by the 180° peel test method. If the test result is ≥70N / cm, the initial adhesion of encapsulating film is qualified.

[0142] (2) Electrical insulation test: Under a certain breakdown voltage, test the resistivity of the encapsulating film. If the breakdown voltage is ≥3kV, the resistivity is >10. 15 If the value is Ω·cm, then the electrical insulation is qualified.

[0143] (3) Heat aging / yellowing stability test: Place the encapsulating film at 85℃ for 1000 h and observe the color change before and after. If ΔE ≤3, the heat aging / yellowing stability is qualified.

[0144] (4) PID288 test: Place the photovoltaic module under double 85 conditions for 288 hours. If the power attenuation value of the photovoltaic module before and after the test is less than 5%, then the anti-PID performance is good.

[0145] Table 1

[0146] project Initial tack (to glass) Electrical insulation Thermal aging / yellowing stability PID288 Example 1 90N / cm <![CDATA[5kV,8.9×10 16 Ohm cm]]> △E=2 3.2% Example 2 88 N / cm <![CDATA[4.5kV,8.5×10 16 Ohm cm]]> △E=2.5 3.8% Example 3 89 N / cm <![CDATA[4.3kV,8.2×10 16 Ohm cm]]> △E=2.6 3.5% Example 4 87 N / cm <![CDATA[4.3kV,7.5×10 16 Ohm cm]]> △E=2.8 3.4% Example 5 85 N / cm <![CDATA[4.5kV,6.9×10 16 Ohm cm]]> △E=2.7 3.4% Example 6 86 N / cm <![CDATA[4.5kV,7.8×10 16 Ohm cm]]> △E=2.9 3.4% Comparative Example 1 78 N / cm <![CDATA[2.5kV,3.8×10 15 Ohm cm]]> △E=3.4 6.9% Comparative Example 2 79 N / cm <![CDATA[3.5kV,5.8×10 15 Ohm cm]]> △E=3.5 6.5% Comparative Example 3 80 N / cm <![CDATA[3.5kV,5.8×10 15 Ohm cm]]> △E=3.2 6.3% Comparative Example 4 76 N / cm <![CDATA[3.5kV,5.8×10 15 Ohm cm]]> △E=3.6 5.5%

[0147] As can be seen from Table 1 above, by adding a certain amount of modified mesoporous material to the encapsulating film, the various properties of the prepared encapsulating film meet the requirements, and the photovoltaic module exhibits excellent PID288 test performance with power attenuation far less than that of conventional POE encapsulating film.

[0148] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0149] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. An encapsulating film, characterized in that, By weight, it includes: 100 parts of film matrix and 12 to 18 parts of modified mesoporous material; The modified mesoporous material includes a mesoporous material and a modifier grafted onto the mesoporous material, wherein the modifier includes one or more crown ethers and polycyclic compounds.

2. The encapsulating film according to claim 1, characterized in that, The raw materials for preparing the modified mesoporous material include a mesoporous material, a modifier, and a silane coupling agent. The mesoporous material has silanol groups, the modifier contains reactive groups, and the general structural formula of the silane coupling agent is: X-(CH2). n -Si(OR)3, where X is an organic functional group and OR is a hydrolyzable group, and the X group in the silane coupling agent can react with the reactive group in the modifier.

3. The encapsulating film according to claim 2, characterized in that, The modified mesoporous material satisfies one or more of the following conditions: (1) The mass ratio of the modifier to the mesoporous material is 1:(5~10); (2) The reactive groups include one or more of amino, hydroxyl, carboxyl and thiol groups; (3) The X group includes one or more of amino, epoxy, mercapto and alkenyl groups; (4) The molar ratio of the silane coupling agent to the modifier is (1~1.2):

1.

4. The encapsulating film according to claim 3, characterized in that, The silane coupling agent comprises one or more of aminopropyltriethoxysilane, epoxypropoxytrimethoxysilane, mercaptopropyltrimethoxysilane, and vinyltriethoxysilane; and / or, The modifier includes one or more of amino-modified crown ethers, amino-modified calixarenes, hydroxyl-modified calixarenes, cyclodextrins, and azacrown ethers.

5. The encapsulating film according to any one of claims 1 to 4, characterized in that, The mesoporous material satisfies one or more of the following conditions: (1) The mesoporous material includes one or more of mesoporous silica and mesoporous molecular sieve; optionally, the mesoporous material includes one or more of SBA-15, MCM-41 and STMS; (2) The specific surface area of ​​the mesoporous material is 500 m². 2 / g~1000m 2 / g; (3) The average pore size of the mesoporous material is 2nm~10nm.

6. The encapsulating film according to any one of claims 1 to 4, characterized in that, The encapsulating film further includes: 1 to 2 parts of a UV light absorber, optionally, the UV light absorber is loaded within the pores of the modified mesoporous material; and / or, The film substrate includes one or more of EVA, POE, and EPE; and / or, The encapsulating film further includes one or more of the following: 1 to 3 parts crosslinking agent, 2 to 3 parts crosslinking aid, 1 to 3 parts coupling agent, and 1 to 3 parts filler.

7. A method for preparing an encapsulating film, characterized in that, Includes the following steps: By weight, 100 parts of the adhesive film matrix and 12 to 18 parts of the modified mesoporous material are mixed and extruded into a film to prepare an encapsulating adhesive film. The modified mesoporous material includes a mesoporous material and a modifier grafted onto the mesoporous material, wherein the modifier includes one or more crown ethers and polycyclic compounds.

8. The method for preparing the encapsulating film according to claim 7, characterized in that, The modified mesoporous material is prepared by the following method: The modifier, the mesoporous material, and at least partially hydrolyzed silane coupling agent are mixed and reacted under a protective atmosphere at 50°C to 70°C for 4 to 12 hours to obtain the modified mesoporous material.

9. The method for preparing the encapsulating film according to claim 8, characterized in that, Prior to the step of mixing the modifier, the mesoporous material, and the at least partially hydrolyzed silane coupling agent, the method further includes: vacuum drying the mesoporous material at 100°C to 150°C for 2 to 4 hours; and / or, The at least partially hydrolyzed silane coupling agent is obtained by dissolving the silane coupling agent in an organic solvent and then mixing it with water for 0.5 h to 1 h, wherein the molar ratio of water to the silane coupling agent is 1:(1~2).

10. A photovoltaic module, characterized in that, The invention includes a solar cell and an encapsulation structure, wherein the encapsulation structure is used to encapsulate the solar cell, and the encapsulation structure includes the encapsulation film according to any one of claims 1 to 6 or includes an encapsulation film prepared by the method for preparing the encapsulation film according to any one of claims 7 to 9. Optionally, the solar cell includes a back-contact solar cell; Optionally, the encapsulation structure further includes glass, the encapsulation film is disposed on both sides of the solar cell, and the glass is disposed on the side of the encapsulation film away from the solar cell.

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