Copolymer grafted with light conversion agent, adhesive film containing copolymer and application of adhesive film

Abstract

The invention belongs to the field of solar cell materials, and provides a copolymer grafted with a light conversion agent, a light conversion adhesive film containing the copolymer, a preparation method of the light conversion adhesive film, a solar cell module containing the light conversion adhesive film and a method for improving the power and / or reliability of the solar cell module. The copolymer grafted with the light conversion agent can be used for a light conversion adhesive film, the absorption wavelength and the emission wavelength of the light conversion adhesive film are regulated and controlled, and meanwhile, the light conversion agent can be prevented from migrating, so that power attenuation and reliability reduction of an actual assembly are avoided. The copolymer grafted with the light conversion agent comprises a repetitive unit A, a repetitive unit B and a repetitive unit C, wherein the definitions of groups in the repetitive unit B and the repetitive unit C are described in the specification.

Description

Technical Field

[0001] This invention belongs to the field of solar cell materials, specifically relating to a copolymer grafted with a light-converting agent, a light-converting film containing the copolymer and its preparation method, a solar cell module containing the light-converting film, and a method for improving the power and / or reliability of the solar cell module. Background Technology

[0002] As the core carrier of photovoltaic technology, solar cells' photoelectric conversion efficiency and long-term stability are crucial to the industry's development. However, both mainstream crystalline silicon cells and emerging perovskite tandem cells face challenges from ultraviolet (UV) radiation. For crystalline silicon cells, especially heterojunction cells, UV radiation damages silicon-hydrogen bonds, affecting module power. Perovskite cells are even more sensitive to UV radiation: UV irradiation accelerates ion migration within the perovskite layer, triggering material degradation and increasing interface defects, severely weakening the cell's long-term stability. Against this backdrop, introducing light-converting agents into the encapsulation film of solar cells to obtain light-converting films with both UV protection and light energy conversion functions has become a breakthrough direction. These films protect the cells from UV damage while improving the utilization rate of long-wavelength light in crystalline silicon or perovskite cells, thus achieving the dual functions of "light management" and "material protection" in the encapsulation layer.

[0003] To save costs, the common encapsulation scheme for photovoltaic modules currently uses a light-converting agent film on the front of the cell and a high-transparency film on the back. The dispersion of the light-converting agent in the light-converting agent film is usually a physical dispersion. Under heating conditions, due to the concentration difference of the light-converting agent between the front and back films, the light-converting agent will migrate from the front of the cell to the back, resulting in a decrease in the concentration of the light-converting agent on the front of the cell, which cannot effectively protect the cell.

[0004] Current methods for preventing migration involve introducing groups into the light-converting agent molecules that can participate in the cross-linking reaction of the film. These groups participate in the cross-linking reaction during the lamination and heating process, grafting the light-converting agent into the cross-linking network. However, this approach of introducing cross-linkable groups into the light-converting agent molecules still has shortcomings. On the one hand, since the degree of cross-linking will not reach 100%, it is difficult for all light-converting agent molecules to participate in the reaction, resulting in free light-converting agent. On the other hand, polyolefin elastomer (POE) films have become an upgraded choice for encapsulation materials due to their low water vapor permeability and anti-PID properties. Compared to silicon solar cells, perovskite modules are more sensitive to ultraviolet light, but thermoplastic POE is typically used as the encapsulation material for perovskite modules. Thermoplastic POE lacks a cross-linking system, making it impossible to prepare anti-migration light-converting films using the aforementioned mechanism.

[0005] Patent application CN117700442A introduces trimethyl(oxy)silicon at the N position of benzotriazole, but this method has low reaction efficiency and cannot be used for thermoplastic POE. Patent application CN117700442A also introduces unsaturated carbon-carbon double bonds into benzotriazole and uses lamination crosslinking to achieve migration prevention, but this also suffers from low reaction efficiency and cannot be used for thermoplastic POE. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention proposes a copolymer grafted with a light-converting agent, a light-converting film containing the copolymer grafted with the light-converting agent, a method for preparing the same, a solar cell module containing the light-converting film, and a method for improving the power and / or reliability of the solar cell module.

[0007] Specifically, the present invention provides a copolymer grafted with a light-converting agent, the copolymer comprising repeating unit A. Repeating unit B and repeating unit C The ratio of the number of repeating units A, B and C is x:y:z, and x, y and z satisfy: y / (x+y) is 0.05~0.1, z / (x+y) is 0.0001~0.0008;

[0008] In repeating unit B, R3 is selected from C2-C6 alkyl groups;

[0009] In the repeating unit C, R1 and R2 are each independently selected from hydrogen atoms, C1-C5 alkyl, C1-C5 alkoxy, halogen atoms, trifluoromethyl, cyano and nitro; L is selected from C6-C10 alkylene; Ar1 ​​and Ar2 are each independently selected from unsubstituted C6-C20 aryl, substituted C6-C20 aryl, unsubstituted five- to twenty-membered heteroaryl and substituted five- to twenty-membered heteroaryl;

[0010] The copolymer has a weight-average molecular weight of 20,000 to 60,000.

[0011] In one or more implementations, x and y satisfy the condition that y / (x+y) is 0.05~0.07.

[0012] In one or more embodiments, x, y, and z satisfy: z / (x+y) is 0.0001~0.0005; preferably, z / (x+y) is 0.0001~0.0002.

[0013] In one or more embodiments, the copolymer has a weight-average molecular weight of 40,000 to 60,000, preferably 45,000 to 55,000, and more preferably 46,000 to 51,000.

[0014] In one or more embodiments, the molecular weight distribution index of the copolymer is ≤5, preferably ≤3, for example 1 to 3.

[0015] In one or more embodiments, in repeating unit B, R3 is selected from C2-C6 straight-chain alkyl groups, preferably from ethyl, n-butyl and n-hexyl, and more preferably n-hexyl.

[0016] In one or more embodiments, in the repeating unit C, R1 and R2 are each independently selected from hydrogen atoms and C1-C5 alkyl groups, preferably from hydrogen atoms and methyl groups.

[0017] In one or more embodiments, in the repeating unit C, L is selected from C6-C10 straight-chain alkylene groups, preferably from 1,6-hexene, 1,7-heptene, 1,8-octene, 1,9-nonene, and 1,10-decene.

[0018] In one or more embodiments, in repeating unit C, the substituents on the substituted C6-C20 aryl group and the substituents on the substituted five- to twenty-membered heteroaryl group are each independently 1-5 substituents selected from C1-C5 alkyl, C1-C5 alkoxy, halogen atom, trifluoromethyl, cyano, nitro, -NR a R b , C6-C10 aryl and five- to twenty-membered heteroaryl groups, R a R b and R c Each is independently selected from H, C1-C5 alkyl and C6-C10 aryl.

[0019] In one or more embodiments, in repeating unit C, Ar1 and Ar2 are each independently substituted phenyl groups, preferably phenyl groups substituted with 1-5 C1-C5 alkyl groups, more preferably phenyl groups substituted with 1 C1-C5 alkyl group at the para position, and preferably 4-tert-butyl-phenyl.

[0020] In one or more embodiments, in the repeating unit C, Ar1 and Ar2 are each independently selected from groups represented by Formulas 1 to 12:

[0021] .

[0022] The present invention also provides a method for preparing the copolymer described in any embodiment herein, the method comprising: reacting ethylene, a compound of formula III... Compounds of Formula II A copolymerization reaction occurs to obtain the copolymer;

[0023] R3 in Formula III is the same as R3 in repeating unit B in claim 1, and R1, R2, L, Ar1, and Ar2 in Formula II are the same as R1, R2, L, Ar1, and Ar2 in repeating unit C in the copolymer of the present invention.

[0024] In one or more embodiments, the catalyst used in the copolymerization reaction includes a main catalyst, said main catalyst being... .

[0025] In one or more embodiments, the amount of the main catalyst is 0.5-5 μmol relative to 70 mL of the compound of formula III.

[0026] In one or more embodiments, the catalyst used in the copolymerization reaction further includes a co-catalyst, wherein the co-catalyst is methylaluminoxane.

[0027] In one or more embodiments, the molar ratio of the co-catalyst to the main catalyst is (200-5000):1.

[0028] In one or more embodiments, the copolymerization reaction is carried out at a pressure of 1.5-5 MPa and at a temperature of 50-160 °C.

[0029] The present invention also provides a light-converting adhesive film, wherein the light-converting adhesive film comprises the copolymer described in any embodiment herein.

[0030] In one or more embodiments, the thickness of the light-converting film is 300-600 μm.

[0031] The present invention also provides a solar cell module, the solar cell module comprising solar cells and a light-converting adhesive film as described in any embodiment herein.

[0032] In one or more embodiments, the solar cell includes a perovskite light-absorbing layer.

[0033] In one or more embodiments, the solar cell module further includes a front glass, with the light-converting adhesive film located between the front glass and the solar cell.

[0034] The present invention also provides a method for improving the power and / or reliability of a solar cell module, the method comprising: introducing a light-converting adhesive film as described in any embodiment of the present invention between the front glass of the solar cell module and the solar cell.

[0035] This invention designs a copolymer grafted with a light-converting agent (also known as a light-converting POE). By introducing a polymerization-participating carbon-carbon double bond into a benzotriazole-based light-converting agent, the agent containing the carbon-carbon double bond is directly introduced into the copolymer as a comonomer during the polymerization process. The light-converting film prepared using this POE avoids the migration of the light-converting agent within the film. In this invention, alkyl, alkoxy, halogen, trifluoromethyl, cyano, or nitro groups can be introduced at positions 5 and 6 of the benzotriazole to control the absorption and emission bands of the light-converting agent. The absorption and emission bands can also be controlled by adjusting the size of the aryl conjugated system. This invention controls the insertion rate of the light-converting agent by varying the proportions of different comonomers, thereby controlling the UV shielding capability. Furthermore, this invention can control the performance of the POE by adjusting the ratio of ethylene to a compound of formula III, ultimately achieving the preparation of a light-converting POE.

[0036] Compared to current POE light-converting films, the POE light-converting film prepared using light-converting POE in this invention does not have the problem of light-converting agent migration, and the absorption and emission spectra can be effectively controlled. The copolymer of the grafted light-converting agent in this invention has a stable structure and can be used to prepare thermoplastic POE light-converting films. The copolymer of the grafted light-converting agent in this invention can be directly used as POE light-converting granules, saving steps. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of a battery module migration experiment. Detailed Implementation

[0038] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used herein are explained and defined in general terms below. Unless otherwise specified, all technical and scientific terms used herein have the common meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0039] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0040] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0041] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0042] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0043] In this article, the sum of the percentages of all components in the composition is 100%.

[0044] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope of this invention.

[0045] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0046] In this invention, alkyl refers to a monovalent saturated group composed of carbon atoms and hydrogen atoms, having a straight-chain or branched structure. In this invention, the number of carbon atoms preceding the group indicates the number of carbon atoms contained in the group; for example, C1 alkyl represents an alkyl group containing one carbon atom, i.e., methyl. Alkyl groups suitable for this invention can be C1-C5 alkyl groups, such as C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, and C5 alkyl.

[0047] In this invention, alkoxy refers to "alkyl-O-". Alkoxy groups suitable for use in this invention can be C1-C5 alkoxy groups, such as C1 alkoxy, C2 alkoxy, C3 alkoxy, C4 alkoxy, and C5 alkoxy.

[0048] In this invention, halogen atoms include F, Cl, Br, and I.

[0049] In this invention, trifluoromethyl refers to "-CF3".

[0050] In this invention, cyano refers to "-CN".

[0051] In this invention, nitro refers to "-NO2".

[0052] In this invention, alkylene refers to a divalent saturated group consisting of carbon atoms and hydrogen atoms, having a straight-chain or branched structure. Preferably, the alkylene is a straight-chain alkylene. Alkylenes suitable for use in this invention can be C6-C10 alkylenes, such as C6 alkylene, C7 alkylene, C8 alkylene, C9 alkylene, and C10 alkylene.

[0053] In this invention, aryl refers to a monovalent group with an aromatic ring structure composed of carbon atoms and hydrogen atoms, and the aryl group is connected to other parts of the molecule through the carbon atoms on the aromatic ring. The aryl groups suitable for this invention can be C6-C20 aryl groups, including but not limited to C6 aryl (e.g., phenyl), C10 aryl (e.g., naphthyl), and C14 aryl (e.g., anthraceneyl, phenanthrene).

[0054] In this invention, a heteroaryl group refers to a monovalent group with an aromatic ring structure composed of carbon atoms, hydrogen atoms, and heteroatoms, wherein the heteroaryl group is connected to other parts of the molecule through carbon atoms or heteroatoms on the aromatic ring. The heteroatoms in the heteroaryl group can be one or more selected from N, P, O, S, Si, and B. The number of heteroatoms in the heteroaryl group can be 1-5. In this invention, a pentagonal to twentieth aryl group refers to a heteroaryl group whose total number of carbon atoms and heteroatoms in the aromatic ring can be 5-20.

[0055] The light-converting POE molecules in the light-converting film of this invention are copolymers of grafted light-converting agents. Using the copolymer of grafted light-converting agents selected in this invention in the light-converting film is beneficial for improving the migration distance of the light-converting agent in solar cell modules, as well as the module power and reliability.

[0056] copolymers of grafted light-converting agents

[0057] In this invention, the copolymer of grafted light-converting agent (hereinafter referred to as copolymer) can be used as the light-converting POE molecule, and the copolymer includes repeating unit A. Repeating unit B and repeating unit C The ratio of the number of repeating units A, B, and C is x:y:z, where x, y, and z satisfy the following: y / (x+y) is 0.05~0.1, for example, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1; z / (x+y) is 0.0001~0.0008, for example, 0.0001, 0.0002, 0.0003, 0.0004, 0.0005, 0.0006, 0.0007, 0.0008.

[0058] In repeating unit B, R3 is selected from C2-C6 alkyl groups;

[0059] In the repeating unit C, R1 and R2 are each independently selected from hydrogen atoms, C1-C5 alkyl, C1-C5 alkoxy, halogen atoms, trifluoromethyl, cyano and nitro; L is selected from C6-C10 alkylene; Ar1 ​​and Ar2 are each independently selected from unsubstituted C6-C20 aryl, substituted C6-C20 aryl, unsubstituted five- to twenty-membered heteroaryl and substituted five- to twenty-membered heteroaryl.

[0060] In some preferred embodiments, y / (x+y) is 0.05~0.07. In some preferred embodiments, x, y, and z satisfy: z / (x+y) is 0.0001~0.0005; more preferably, z / (x+y) is 0.0001~0.0002.

[0061] In this invention, the weight-average molecular weight of the copolymer can be 20,000 to 60,000, preferably 40,000 to 60,000, for example 40,000, 41,000, 42,000, 43,000, 44,000, 45,000, 46,000, 47,000, 48,000, 49,000, 50,000, 51,000, 52,000, 53,000, 54,000, 55,000, 56,000, 57,000, 58,000, 59,000, and 60,000.

[0062] In this invention, the molecular weight fraction index of the copolymer can be ≤, preferably ≤3, for example 1, 1.5, 2, 2.5, 3 or any two of the aforementioned values.

[0063] In this invention, in repeating unit B, R3 is preferably selected from C2-C6 straight-chain alkyl groups, more preferably from ethyl, n-butyl and n-hexyl groups, and even more preferably n-hexyl groups.

[0064] In some embodiments, in the repeating unit C, R1 and R2 are each independently selected from hydrogen atoms and C1-C5 alkyl groups, preferably from hydrogen atoms and methyl groups.

[0065] In some embodiments, in the repeating unit C, L is selected from C6-C10 straight-chain alkylene groups, preferably from 1,6-hexene, 1,7-heptene, 1,8-octene, 1,9-nonene, and 1,10-decene.

[0066] In some embodiments, in the repeating unit C, the substituents on the C6-C20 aryl groups that replace Ar1 and Ar2, and the substituents on the substituted five- to twenty-membered heteroaryl groups, are each independently 1-5 substituents selected from C1-C5 alkyl, C1-C5 alkoxy, halogen atom, trifluoromethyl, cyano, nitro, -NR a R b , C6-C10 aryl and five- to twenty-membered heteroaryl groups, R a R b and R c Each is independently selected from H, C1-C5 alkyl and C6-C10 aryl.

[0067] In some embodiments, Ar1 and Ar2 in repeating unit C are each independently substituted phenyl groups, preferably phenyl groups substituted with 1-5 C1-C5 alkyl groups, more preferably phenyl groups substituted with 1 C1-C5 alkyl group at the para position, preferably 4-tert-butyl-phenyl.

[0068] In some embodiments, Ar1 and Ar2 are each independently selected from the groups shown in Formulas 1 to 12:

[0069] ;

[0070] In Formulas 1 to 12, * indicates the position where the group is attached to the benzene ring of the repeating unit C.

[0071] The copolymer of the grafted light-converting agent of the present invention can be used to prepare light-converting films.

[0072] Preparation of copolymers grafted with light-converting agents

[0073] The copolymer of the present invention comprises ethylene and a compound of formula III. Compounds of Formula II It is prepared by copolymerization. R3 in Formula III is the same as R3 in the repeating unit B mentioned above, and R1, R2, L, Ar1, and Ar2 in Formula II are the same as R1, R2, L, Ar1, and Ar2 in the repeating unit C mentioned above.

[0074] In this invention, the compound of formula III is preferably 1-octene.

[0075] In this invention, the catalyst used in the copolymerization reaction includes a main catalyst, which is... The term "primary catalyst" is well-known to those skilled in the art; it refers to the catalyst that enables the polymerization reaction to proceed normally. This invention discovers the use of... As the main catalyst, it can successfully catalyze the copolymerization of ethylene, compound III, and compound II to obtain the copolymer of the present invention. However, it is difficult to catalyze the copolymerization of ethylene, compound III, and compound II using other main catalysts, such as those using… The copolymer of the present invention cannot be prepared by using a blend with a Ziegler-Natta catalyst as the main catalyst.

[0076] The copolymerization reaction system of the present invention may also include a co-catalyst, such as methylaluminoxane (MMAO). The term "co-catalyst" is well known to those skilled in the art; it refers to a catalyst used to enhance the activity of the main catalyst.

[0077] In some embodiments, the copolymers of the present invention are synthesized via the following route:

[0078] Ethylene, compound III, compound II, solvent, and co-catalyst are added to the reactor. The ethylene pressure is controlled at 0.1-0.4 MPa, and the temperature is raised to 50-160 °C. Then, the ethylene pressure is adjusted to 1.5-5 MPa, and the main catalyst is added. The reaction was carried out for 10-15 minutes to obtain the copolymer.

[0079] When preparing copolymers, n-heptane can be used as the solvent.

[0080] The feed amounts of ethylene, Formula III compound, and Formula II compound can be adjusted based on the x, y, z values ​​and molecular weight of the copolymer.

[0081] In this invention, the compound of formula II can be dissolved in a solvent (e.g., n-heptane) before being added to the reaction system.

[0082] In this invention, the main catalyst can be dissolved in toluene first, and then added to the reaction system.

[0083] In this invention, relative to 70 mL of 1-octene, the main catalyst The dosage can be 0.5-5 μmol, for example 0.6 μmol, 0.8 μmol, 1 μmol, 2 μmol, 3 μmol, 4 μmol.

[0084] In this invention, the amount of co-catalyst (e.g., methylaluminoxane) used relative to 70 mL of 1-octene can be 0.25-25 mmol, for example 0.4 mmol, 0.5 mmol, 0.6 mmol, 0.8 mmol, 1 mmol, 2 mmol, 5 mmol, 10 mmol, 15 mmol, or 20 mmol.

[0085] The amount of co-catalyst can be adjusted according to the amount of main catalyst. The molar ratio of co-catalyst to main catalyst can be (200-5000):1, for example 300:1, 400:1, 500:1, 600:1, 800:1, 1000:1, 2000:1, 3000:1, 4000:1.

[0086] In this invention, the pressure of the copolymerization reaction can be 1.5-5 MPa, for example 2 MPa, 3 MPa, or 4 MPa. The temperature of the copolymerization reaction is 50-160 °C, preferably 100-160 °C, for example 110 °C, 120 °C, 130 °C, 140 °C, or 150 °C.

[0087] Synthesis of Compound II

[0088] In this invention, the structure of compound II is as follows:

[0089] .

[0090] It is understood that R1, R2, L, Ar1 and Ar2 in Formula II are the same as R1, R2, L, Ar1 and Ar2 in repeating unit C of the copolymer of the present invention.

[0091] In this invention, the compound of formula II can be synthesized via the following route:

[0092] ;

[0093] Step 1: Dissolve 0.1 mol of compound III in 50 mL of acetic acid. Under ice bath conditions, add a total of 0.25 mol of N-succinimide bromide, heat to 100 °C and reflux for 6 h. After the reaction is complete, allow the reaction system to cool to room temperature, pour it into a saturated sodium bisulfite solution and stir for 30 min. Then filter and collect the filter cake, and purify by recrystallization from methanol to obtain intermediate product 1.

[0094] Step 2: Under an inert gas atmosphere, add 0.1 mol of intermediate product 1 and 0.12 mol of... (X is a halogen) 0.3 mol potassium carbonate was added to 200 mL dimethylformamide. The reaction mixture was heated and stirred at 40 °C for 24 h under an inert atmosphere, then poured into ice water and stirred for 30 min. It was then extracted with sufficient dichloromethane, dried with anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. Finally, it was purified by column chromatography to obtain intermediate product 2.

[0095] Step 3: Under an inert gas atmosphere, 0.1 mol of intermediate product 2 and 0.25 mol of Ar-boronic acid were dissolved in 100 mL of toluene. 20 mmol of tetrakis(triphenylphosphine)palladium(0), 0.2 mol of sodium carbonate and 10 mL of deionized water were added. The mixture was heated to 120 °C and refluxed for 24 h. After cooling to room temperature, 200 mL of water was added to the reaction flask to quench the reaction. The mixture was extracted three times with dichloromethane, dried with anhydrous magnesium sulfate, and the solvent was evaporated. The target product was purified by column chromatography to finally obtain compound II.

[0096] Preparation of optical transfer film

[0097] The light-converting film of the present invention can be prepared by laminating a copolymer of the grafted light-converting agent of the present invention.

[0098] The lamination temperature can be 120 ℃-150 ℃, for example 120 ℃, 130 ℃, 140 ℃, 150 ℃. The lamination time can be 10-20 min, for example 10 min, 11 min, 12 min, 13 min, 14 min, 15 min, 16 min, 17 min, 18 min, 19 min, 20 min.

[0099] In some embodiments, the thickness of the light-converting adhesive film of the present invention is 300-600 μm, for example 300 μm, 350 μm, 380 μm, 400 μm, 450 μm, 480 μm, 500 μm, 550 μm, 600 μm.

[0100] Solar cell modules

[0101] The module is obtained by arranging the front glass, light-converting film, solar cell, high-transparency film and back glass in sequence. The side of the light-converting film of the present invention is the front of the solar cell. The module is placed in a laminator for lamination (for example, first vacuuming at 145 ℃ for 6 min, then maintaining 145 ℃, and then holding at -80 kPa for 60 s, -60 kPa for 60 s, and -20 kPa for 600 s in sequence). After lamination, it is taken out and cooled to room temperature (25 ℃) to obtain the solar cell module.

[0102] The light-converting film of the present invention, made from a copolymer of grafted light-converting agents, reduces the migration distance of the light-converting agent in solar cell modules, thereby improving the power and reliability of solar cell modules.

[0103] The present invention has the following beneficial effects:

[0104] This invention designs a copolymer grafted with a light-converting agent (also known as a light-converting POE). By introducing a polymerization-participating carbon-carbon double bond into a benzotriazole-based light-converting agent, the agent containing the carbon-carbon double bond is directly introduced into the copolymer as a comonomer during the polymerization process. The light-converting film prepared using this POE avoids the migration of the light-converting agent within the film. In this invention, alkyl, alkoxy, halogen, trifluoromethyl, cyano, or nitro groups can be introduced at positions 5 and 6 of the benzotriazole to control the absorption and emission bands of the light-converting agent. The absorption and emission bands can also be controlled by adjusting the size of the aryl conjugated system. This invention controls the insertion rate of the light-converting agent by varying the proportions of different comonomers, thereby controlling the UV shielding capability. Furthermore, this invention can control the performance of the POE by adjusting the ratio of ethylene to a compound of formula III, ultimately achieving the preparation of a light-converting POE.

[0105] This invention is based on a copolymer of grafted light-converting agents designed with benzotriazole. While controlling spectral absorption and emission, it can prevent the migration of light-converting agents, thereby avoiding power decay and reduced reliability of actual components.

[0106] Compared to current POE light-converting films, the POE light-converting film prepared using light-converting POE in this invention does not have the problem of light-converting agent migration, and the absorption and emission spectra can be effectively controlled. The copolymer of the grafted light-converting agent in this invention has a stable structure and can be used to prepare thermoplastic POE light-converting films. The copolymer of the grafted light-converting agent in this invention can be directly used as POE light-converting granules, saving steps.

[0107] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments and comparative examples are conventional methods, reagents, and materials in the art, unless otherwise stated. The starting material compounds in the embodiments and comparative examples are all commercially available.

[0108] Example 1

[0109] Example 1 provides a light-converting adhesive film and a corresponding device using copolymer 1 as the light-converting POE molecule. Copolymer 1 includes repeating unit A. Repeating unit B1 and repeating unit C1 The ratio of the number of repeating units A, B1 and C1 is x:y:z, where x, y and z are 0.93, 0.07 and 0.0001, respectively.

[0110] The synthetic route for copolymer 1 is as follows:

[0111] ;

[0112] Step 1: Dissolve 0.1 mol of 2H-benzo[d][1,2,3]triazole in 50 mL of acetic acid. Add 0.25 mol of N-succinimide bromide under ice bath conditions, then heat to reflux temperature of 100 °C and react for 6 h. After the reaction is complete, allow the reaction system to cool to room temperature, then pour it into a saturated sodium bisulfite solution and stir for 30 min. Filter and collect the filter cake, then recrystallize from methanol to obtain intermediate product 1.

[0113] Step 2: Under an inert gas atmosphere, 0.1 mol of intermediate product 1, 0.12 mol of 8-bromo-1-octene, and 0.3 mol of potassium carbonate were added to 200 mL of dimethylformamide. The reaction mixture was heated and stirred at 40 °C for 24 h under an inert atmosphere, then poured into ice water and stirred for 30 min. It was then extracted with sufficient dichloromethane, dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. Finally, intermediate product 2 was purified by column chromatography.

[0114] Step 3: Under an inert gas atmosphere, 0.1 mol of intermediate product 2 and 0.25 mol of 4-tert-butylphenylboronic acid were dissolved in 100 mL of toluene. 20 mmol of tetrakis(triphenylphosphine)palladium (0), 0.2 mol of sodium carbonate, and 10 mL of deionized water were added. The mixture was heated to 120 °C and refluxed for 24 h. After cooling to room temperature, 200 mL of water was added to the reaction flask to quench the reaction. The mixture was extracted three times with dichloromethane, dried over anhydrous magnesium sulfate, and the solvent was evaporated. The mixture was purified by column chromatography to obtain intermediate product 3, which is a light-converting agent a containing carbon-carbon double bonds. ). The light-converting agent a 1 ¹H NMR (400 MHz, deuterated chloroform): δ=7.99(d, J=7.7Hz, 4H), 7.55(s, 2H), 7.05(d, J=7.6Hz, 4H), 5.04-4.86(m, 3H), 4.43(t, J=7.3Hz, 2H), 2.17-2.08(m, 2H), 2.02-1.93(m, 2H), 1.38-1.28(m, 24H); MALDI-TOF result was 493.7.

[0115] Step 4: The 500 mL high-pressure reactor was pre-vacuum dried for 2 h. The reactor temperature was adjusted to the polymerization temperature of 140 °C, and the ethylene gas pressure was set to 0.3 MPa. First, 200 mL of n-heptane, 70 mL of 1-octene, and 0.05 g of the n-heptane solvent containing the light-converting agent a were added. Then, 0.5 mmol of methylaluminoxane (MMAO) was added, and the reactor temperature was raised to 140 °C. After reaching 140 °C, the ethylene pressure was adjusted to 2.5 MPa, and 2 μmol of the main catalyst was injected. The toluene solution was polymerized for 10 min, and then ethanol was added to quench the polymerization. After depressurization, the compound was discharged from the bottom of the reactor. The resulting polymer solution was poured into 500 mL of ethanol and stirred to obtain a white solid. The solid was filtered and dried in a vacuum oven to constant weight to obtain a white polymer.

[0116] Example 1: A POE light-converting film was prepared in the following manner:

[0117] The obtained copolymer 1 was laminated using a laminator (150 ℃, 600 s) to obtain a POE light-converting film with a thickness of 450 μm.

[0118] In this embodiment 1, the battery assembly is prepared in the following manner:

[0119] The module is obtained by arranging the patterned glass, POE light-converting film, TOPCon solar cell, high-transparency film, and patterned glass in that order, with the side of the POE light-converting film facing the front of the solar cell. The module is then placed in a laminator for lamination (first, vacuuming at 145 ℃ for 6 min, then maintaining 145 ℃ and sequentially holding at -80 kPa for 60 s, -60 kPa for 60 s, and -20 kPa for 600 s). After the process, the module is removed and cooled to room temperature (25 ℃) to obtain the solar cell module of Example 1.

[0120] In the copolymer 1 prepared in Example 1, the amount of light-converting agent a added was 0.05 g. The weight-average molecular weight and molecular weight distribution index of copolymer 1 were 51,000 and 2.1, respectively. In terms of mechanical properties, the tensile strength of the prepared POE light-converting film was 3.3 MPa. In terms of optical properties, the maximum absorption wavelength of the prepared POE light-converting film was 345 nm, the maximum emission wavelength was 420 nm, the quantum yield was 92%, the transmittance in the 280-380 nm range was 2.2%, the maximum migration distance of the light-converting agent was 0, and the power attenuation rate of the module after 60 kWh of UV irradiation was 0.9%.

[0121] Example 2

[0122] Example 2 provides a light-converting adhesive film and a corresponding device using copolymer 2 as the light-converting POE molecule, wherein copolymer 2 includes repeating unit A. Repeating unit B1 and repeating unit C1 The ratio of the number of repeating units A, B1 and C1 is x:y:z, where x, y and z are 0.93, 0.07 and 0.0002, respectively.

[0123] The synthesis methods of copolymer 2 and copolymer 1 are basically the same, except that the 0.05 g of light-converting agent a in step 4 is replaced with 0.1 g of light-converting agent a.

[0124] The POE light-converting film of Example 2 was prepared according to the method of Example 1, except that copolymer 1 was replaced with copolymer 2. The POE light-converting film with a thickness of 450 μm was obtained.

[0125] The battery module of Example 2 was prepared according to the method of Example 1, except that the POE light-converting film prepared in Example 1 was replaced with the POE light-converting film prepared in Example 2.

[0126] In copolymer 2 prepared in Example 2, the amount of light-converting agent a added was 0.1 g. The weight-average molecular weight and molecular weight distribution index of copolymer 2 were 48,000 and 3.0, respectively. In terms of mechanical properties, the tensile strength of the prepared POE light-converting film was 3.2 MPa. In terms of optical properties, the maximum absorption wavelength of the prepared POE light-converting film was 345 nm, the maximum emission wavelength was 420 nm, the quantum yield was 94%, the transmittance in the 280-380 nm range was 1.6%, the maximum migration distance of the light-converting agent was 0, and the power attenuation rate of the module after 60 kWh of UV irradiation was 0.8%.

[0127] Example 3

[0128] Example 3 provides a light-converting adhesive film and a corresponding device using copolymer 3 as the light-converting POE molecule, wherein copolymer 3 includes repeating unit A. Repeating unit B1 and repeating unit C2 The ratio of the number of repeating units A, B1 and C2 is x:y:z, where x, y and z are 0.93, 0.07 and 0.0002, respectively.

[0129] The first to third steps of the copolymer synthesis in Example 3 are basically the same as those in Example 1, except that the 2H-benzo[d][1,2,3]triazole in the first step is replaced with 6-methyl-2H-benzo[d][1,2,3]triazole.

[0130] The intermediate product 3 obtained in the third step of Example 3 is a light-converting agent b containing carbon-carbon double bonds. ), light-converting agent b 1¹H NMR (400 MHz, deuterated chloroform): δ = 7.90 (s, 1H), 7.40 (d, J = 7.5 Hz, 4H), 7.30 (d, J = 7.5 Hz, 4H), 5.04–4.86 (m, 3H), 4.43 (t, J = 7.3 Hz, 2H), 2.42 (s, 3H), 2.17–2.08 (m, 2H), 2.02–1.93 (m, 2H), 1.38–1.28 (m, 24H); MALDI-TOF result: 507.8.

[0131] Copolymer 3 was prepared according to step 4 of Example 1, except that 0.05 g of light-converting agent a was replaced with 0.1 g of light-converting agent b, and copolymer 3 was obtained after the reaction.

[0132] The POE light-converting film of Example 3 was prepared according to the method of Example 1, except that copolymer 1 was replaced with copolymer 3. The POE light-converting film with a thickness of 450 μm was obtained.

[0133] The battery module of Example 3 was prepared according to the method of Example 1, except that the POE light transfer film prepared in Example 1 was replaced with the POE light transfer film prepared in Example 3.

[0134] In the copolymer 3 prepared in Example 3, the amount of light-converting agent b added was 0.1 g. The weight-average molecular weight and molecular weight distribution index of copolymer 3 were 49,000 and 2.6, respectively. Regarding mechanical properties, the tensile strength of the prepared POE light-converting film was 3.2 MPa. Regarding optical properties, the maximum absorption wavelength of the prepared POE light-converting film was 325 nm, the maximum emission wavelength was 400 nm, the quantum yield was 93%, the transmittance in the 280-360 nm range was 1.5%, the maximum migration distance of the light-converting agent was 0, and the power decay rate of the module after 60 kWh of UV irradiation was 1.1%.

[0135] Example 4

[0136] Example 4 provides a light-converting adhesive film and a corresponding device using copolymer 4 as the light-converting POE molecule, wherein copolymer 4 includes repeating unit A. Repeating unit B1 and repeating unit C3 The ratio of the number of repeating units A, B1 and C3 is x:y:z, where x, y and z are 0.93, 0.07 and 0.0005 respectively.

[0137] The first to third steps of copolymer 4 are basically the same as the synthesis method in Example 1, except that 8-bromo-1-octene in the second step is replaced with 11-bromo-1-undecene.

[0138] The intermediate product 3 obtained in the third step of Example 4 is a light-converting agent c containing carbon-carbon double bonds. ), light-converting agent C 1 ¹H NMR (400 MHz, deuterated chloroform): δ=7.99(d, J=7.7Hz, 4H), 7.55(s, 2H), 7.05(d, J=7.6Hz, 4H), 5.04-4.86(m, 3H), 4.43(t, J=7.3Hz, 2H), 2.17-2.08(m, 2H), 2.02-1.93(m, 2H), 1.38-1.28(m, 30H); MALDI-TOF result was 535.8.

[0139] Copolymer 4 was prepared according to step 4 of Example 1, except that 0.05 g of light-converting agent a was replaced with 0.3 g of light-converting agent c, and copolymer 4 was obtained after the reaction.

[0140] The POE light-converting film of Example 4 was prepared according to the method of Example 1, except that copolymer 1 was replaced with copolymer 4. The POE light-converting film with a thickness of 450 μm was obtained.

[0141] The battery module of Example 4 was prepared according to the method of Example 1, except that the POE light-converting film prepared in Example 1 was replaced with the POE light-converting film prepared in Example 4.

[0142] In the copolymer 4 prepared in Example 4, the amount of light-converting agent c added was 0.3 g. The weight-average molecular weight and molecular weight distribution index of copolymer 4 were 46,000 and 2.7, respectively. Regarding mechanical properties, the tensile strength of the prepared POE light-converting film was 3.1 MPa. Regarding optical properties, the maximum absorption wavelength of the prepared POE light-converting film was 345 nm, the maximum emission wavelength was 420 nm, the quantum yield was 95%, the transmittance in the 280-380 nm range was 1.7%, the maximum migration distance of the light-converting agent was 0, and the power attenuation rate of the module after 60 kWh of UV irradiation was 0.8%.

[0143] Example 5

[0144] Example 5 provides a light-converting adhesive film and a corresponding device using copolymer 5 as the light-converting POE molecule, wherein copolymer 5 includes repeating unit A. Repeating unit B1 and repeating unit C1 The ratio of the number of repeating units A, B1 and C1 is x:y:z, where x, y and z are 0.93, 0.07 and 0.0008 respectively.

[0145] The synthesis methods of copolymer 5 and copolymer 1 are basically the same, except that the 0.05 g of light-converting agent a in the fourth step is replaced with 0.4 g of light-converting agent a.

[0146] The POE light-converting film of Example 5 was prepared according to the method of Example 1, except that copolymer 1 was replaced with copolymer 5. The POE light-converting film with a thickness of 450 μm was obtained.

[0147] The battery module of Example 5 was prepared according to the method of Example 1, except that the POE light-converting film prepared in Example 1 was replaced with the POE light-converting film prepared in Example 5.

[0148] In the copolymer 5 prepared in Example 5, the amount of light-converting agent a added was 0.4 g. The weight-average molecular weight and molecular weight distribution index of copolymer 5 were 20,000 and 2.6, respectively. Regarding mechanical properties, the tensile strength of the prepared POE light-converting film was 1.2 MPa. Regarding optical properties, the maximum absorption wavelength of the prepared POE light-converting film was 345 nm, the maximum emission wavelength was 420 nm, the quantum yield was 93%, the transmittance in the 280-380 nm range was 1.5%, the maximum migration distance of the light-converting agent was 0, and the power attenuation rate of the module after 60 kWh of UV irradiation was 0.8%.

[0149] Comparative Example 1

[0150] Comparative Example 1 provides a light-converting film and a corresponding device using copolymer 6 as the light-converting POE molecule, wherein copolymer 6 includes repeating unit A. Repeating unit B1 and repeating unit C1 The ratio of the number of repeating units A, B1 and C1 is x:y:z, where x, y and z are 0.93, 0.07 and 0.00005 respectively.

[0151] The synthesis methods of copolymer 6 and copolymer 1 are basically the same, except that the 0.05 g of light-converting agent a in step 4 is replaced with 0.025 g of light-converting agent a.

[0152] The POE light-converting film of Comparative Example 1 was prepared according to the method of Example 1, except that copolymer 1 was replaced with copolymer 6. The POE light-converting film with a thickness of 450 μm was obtained.

[0153] The battery module of Comparative Example 1 was prepared according to the method of Example 1, except that the POE light-converting film prepared in Example 1 was replaced with the POE light-converting film prepared in Comparative Example 1.

[0154] In copolymer 6 prepared in Comparative Example 1, the amount of light-converting agent a added was 0.025 g. The weight-average molecular weight and molecular weight distribution index of copolymer 6 were 58,000 and 2.1, respectively. Regarding mechanical properties, the tensile strength of the prepared POE light-converting film was 3.3 MPa. Regarding optical properties, the maximum absorption wavelength of the prepared POE light-converting film was 345 nm, the maximum emission wavelength was 420 nm, the quantum yield was 90%, the transmittance in the 280-380 nm range was 16.8%, the maximum migration distance of the light-converting agent was 0, and the power decay rate of the module after 60 kWh of UV irradiation was 1.6%.

[0155] Comparative Example 2

[0156] The objective of Comparative Example 2 is to prepare copolymer 7, which includes repeating unit A. Repeating unit B1 and repeating unit C1 The ratio of the number of repeating units A, B1 and C1 is x:y:z, where x, y and z are 0.93, 0.07 and 0.001 respectively.

[0157] The synthesis method of copolymer 7 is basically the same as that of copolymer 1, except that the 0.05 g of light-converting agent a in the fourth step is replaced with 0.5 g of light-converting agent a. After the reaction, copolymer 7 cannot be obtained.

[0158] Comparative Example 3

[0159] The objective of Comparative Example 3 is to prepare copolymer 8, which includes repeating unit A. Repeating unit B1 and repeating unit C4 The ratio of the number of repeating units A, B1 and C4 is x:y:z.

[0160] The first to third steps of the preparation process of copolymer 8 are basically the same as the synthesis method of Example 1, except that 8-bromo-1-octene in the second step is replaced with 4-bromo-1-butene.

[0161] In the third step of Comparative Example 3, intermediate product 3 was obtained, which was a light-converting agent d containing carbon-carbon double bonds. ), light-converting agent d 1¹H NMR (400 MHz, deuterated chloroform): δ = 7.99 (d, J = 7.7 Hz, 4H), 7.55 (s, 2H), 7.05 (d, J = 7.6 Hz, 4H), 5.04–4.86 (m, 3H), 4.43 (t, J = 7.3 Hz, 2H), 2.17–2.08 (m, 2H), 2.02–1.93 (m, 2H), 1.33 (s, 18H); MALDI-TOF result was 437.6.

[0162] Copolymer 8 was prepared according to step 4 of Example 1, except that 0.05 g of light-converting agent a was replaced with 0.1 g of light-converting agent d. After the reaction, copolymer 8 could not be obtained.

[0163] Comparative Example 4

[0164] The first to fourth steps of Comparative Example 4 are basically the same as the synthesis method of Example 1, except that the main catalyst in the fourth step is changed from... Replace with The blended catalytic system with Ziegler-Natta catalyst (brand name TH-1, purchased from Hainan Yulin Enterprise Management Service Co., Ltd.) showed that an optimal mass ratio of 10:1 to 1:10 was used. The copolymer could not be obtained when the blended catalytic system with Ziegler-Natta catalyst was used as the main catalyst.

[0165] Comparative Example 5

[0166] Comparative Example 5 provides a compound 9 ( ( ) Light-converting adhesive film and corresponding devices using light-converting agent.

[0167] The preparation process of compound 9 is as follows:

[0168] ;

[0169] Step 1: Under an inert gas atmosphere, 0.1 mol of 2H-benzo[d][1,2,3]triazole, 0.12 mol of isobutane iodo, and 0.3 mol of potassium carbonate were added to 200 mL of dimethylformamide and mixed thoroughly. The reaction mixture was heated and stirred at 40 °C for 24 h under an inert gas atmosphere, then poured into ice water and stirred for 30 min. The mixture was then extracted with sufficient dichloromethane, dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. Finally, the product was purified by column chromatography to obtain intermediate 1.

[0170] Step 2: Dissolve 0.1 mol of intermediate 1 obtained in Step 1 in 50 mL of acetic acid. Add 0.25 mol of N-succinimide bromide in three equal portions under ice bath conditions, then heat to reflux temperature and react for 6 h. After the reaction system cools to room temperature, pour the reactants into a saturated sodium bisulfite solution and stir for 30 min. Then extract with sufficient dichloromethane, dry with anhydrous magnesium sulfate, remove the solvent under reduced pressure, and finally purify by column chromatography to obtain intermediate 2.

[0171] Step 3: Under an inert gas atmosphere, 0.1 mol of intermediate product 2 and 0.25 mol of 4-tert-butylphenylboronic acid were dissolved in 100 mL of toluene. Then, 20 mmol of tetrakis(triphenylphosphine)palladium(0), 0.2 mol of sodium carbonate, and 10 mL of deionized water were added. The mixture was heated to 120 °C and refluxed for 24 h. After the reaction was completed, it was cooled to room temperature, quenched with 200 mL of deionized water, extracted three times with dichloromethane, dried over anhydrous magnesium sulfate, and the solvent was evaporated. The target product was purified by column chromatography, yielding compound 9. 1 ¹H NMR (400 MHz, deuterated chloroform): δ = 7.99 (d, J = 7.7 Hz, 4H), 7.55 (s, 2H), 7.05 (d, J = 7.6 Hz, 4H), 4.41 (d, J = 7.3 Hz, 2H), 2.05–1.95 (m, 1H), 1.40 (s, 9H), 1.33 (s, 18H), 0.91 (d, J = 7.3 Hz, 6H). MALDI-TOF result: 439.6.

[0172] Compound 9 prepared in Comparative Example 5 and POE particles were simultaneously added to a mixer (100 °C, 10 min) at a mass ratio of 0.15:100. After lamination with a laminator (150 °C, 600 s), a light-converting film with a thickness of 450 μm was obtained.

[0173] The battery module of Comparative Example 5 was prepared according to the preparation method of Example 1, except that the POE light-converting film prepared in Example 1 was replaced with the POE light-converting film prepared in Comparative Example 5.

[0174] In terms of mechanical properties, the tensile strength of the POE light-converting film prepared in Comparative Example 5 is 3.2 MPa. In terms of optical properties, the maximum absorption wavelength of the POE light-converting film prepared in Comparative Example 5 is 345 nm, the maximum emission wavelength is 420 nm, the quantum yield is 93%, the transmittance in the 280-380 nm range is 1.8%, the maximum migration distance of the light-converting agent is 2.8 cm, and the power decay rate of the module after 60 kWh of UV irradiation is 0.9%.

[0175] Test case

[0176] I. Molecular parameter testing of optically converted POE

[0177] The molecular weight and molecular weight distribution index of the optically converted POE molecules in all examples and comparative examples were determined by dissolving the optically converted POE molecules in 1,2,4-trichlorobenzene at 150 °C using PL-GPC 220 high-temperature gel permeation chromatography.

[0178] The methods for testing the content of x, y, and z in the structure of the optically converted POE molecule in all examples and comparative examples were as follows: the proton and carbon spectra were tested using a Bruker 400 MHz NMR spectrometer at a high temperature of 120 °C, and the results were calculated. The solvent used was C2D2Cl4.

[0179] II. Photophysical property testing

[0180] The test method for the absorption wavelength of POE light-converting films in all examples and comparative examples: The POE light-converting films laminated by a laminator (150 °C, 600 s) were tested using a UV spectrophotometer.

[0181] The quantum yield and emission wavelength in all examples and comparative examples were tested using an Edinburgh FLS 1000 fluorescence spectrometer on the POE phototransfer film laminated using a laminator (150 °C, 600 s).

[0182] The transmittance test method in all examples and comparative examples was as follows: the transmittance of the POE light-converting film after lamination by a laminator (150 °C, 600 s) was tested using a fiber optic spectrometer.

[0183] III. Tensile Strength Test

[0184] The testing methods for the tensile strength of POE light-converting adhesive films in all examples and comparative examples were as follows: The copolymers from Examples 1-5 and Comparative Example 1 were laminated using a laminator (150 °C, 600 s) to prepare a film with a thickness of 450 μm. Alternatively, Compound 9 prepared in Comparative Example 5 and POE particles were simultaneously added to a mixer (100 °C, 10 min) at a mass ratio of 0.15:100 and mixed uniformly. The mixture was then laminated using a laminator (150 °C, 600 s) to obtain a film with a thickness of 450 μm. Standard dumbbell-shaped specimens were then prepared from the film using a mold, and tensile tests were performed using a universal testing machine to read the tensile strength values.

[0185] IV. Migration Resistance Test

[0186] The battery module was baked in an oven at 105 °C for 200 h. Some of the light-converting agent migrated from the light-converting film containing the agent to the light-converting film without the agent, and gradually migrated towards the center of the light-converting film without the agent. After the battery module was removed and cooled to room temperature (25 °C), it was irradiated with 365 nm ultraviolet light from the back of the battery module. The light-converting agent emitted fluorescence. Then, the farthest distance the light-converting agent migrated towards the center was measured, starting from the edge of the battery cell.

[0187] V. Aging Resistance Test

[0188] After the battery assembly was connected to the junction box, it was placed in an ultraviolet chamber for aging testing. The ultraviolet chamber conditions were: using a UV2000 ultraviolet aging chamber from Shanghai Eryuan Testing Equipment Co., Ltd. at 60℃ and an irradiation power of 180 W / m². 2 Irradiation dose 60 kWh / m 2 Irradiation was carried out under specific conditions. After irradiation, the power difference before and after irradiation was compared to determine the degradation ratio. The power of the solar cell module was tested using a Pasan IV tester. The power degradation ratio was calculated using the formula: (Power after irradiation - Initial power) / Initial power * 100%, and the power degradation after aging was tested.

[0189] The test results of Examples 1-5 and Comparative Examples 1-5 are shown in Table 1.

[0190] A schematic diagram of the battery module migration experiment is shown below. Figure 1 As shown.

[0191] Table 1: Performance test results of POE light-converting adhesive films and modules in Examples 1-5 and Comparative Examples 1-5

[0192] Example x, y, z ratio weight average molecular weight Molecular weight distribution index Tensile strength Maximum absorption wavelength Maximum emission wavelength Quantum yield transmittance of the cutoff region Maximum migration distance <![CDATA[UV60KWh / m 2 Post-power attenuation ratio]]> Example 1 0.93: 0.07:0.0001 51 k 2.1 3.3MPa 345 nm 420 nm 92 % 2.2 % 0 0.9 % Example 2 0.93: 0.07:0.0002 48 k 3.0 3.2MPa 345 nm 420 nm 94 % 1.6 % 0 0.8 % Example 3 0.93: 0.07:0.0002 49 k 2.6 3.2MPa 325 nm 400 nm 93 % 1.5 % 0 1.1 % Example 4 0.93: 0.07:0.0005 46 k 2.7 3.1MPa 345 nm 420 nm 95 % 1.7 % 0 0.8 % Example 5 0.93: 0.07:0.0008 20 k 2.6 1.2MPa 345 nm 420 nm 93 % 1.5 % 0 0.8 % Comparative Example 1 0.93: 0.07:0.00005 58 k 2.1 3.3MPa 345 nm 420 nm 90 % 16.8 % 0 1.6 % Comparative Example 2 0.93: 0.07: 0.001 (Cannot be prepared) / / / / / / / / / Comparative Example 3 / / / / / / / / / / Comparative Example 4 / / / / / / / / / / Comparative Example 5 / / / 3.2MPa 345 nm 420 nm 93 % 1.8 % 2.8 cm 0.9 %

[0193] As can be seen from Examples 1-2 and Comparative Example 1 in Table 1, when too few light-converting agent molecules are added, the UV shielding effect will be reduced, thereby increasing the transmittance in the UV region and affecting the UV reliability of the component.

[0194] As can be seen from Examples 1-2 and Comparative Example 2 in Table 1, when too many light-converting agent molecules are added, the light-converting molecules themselves are polar molecules, which are not conducive to the polymerization reaction. Therefore, the addition of too many light-converting agent molecules will result in the inability to prepare copolymers.

[0195] As can be seen from Examples 1-4 and Example 5 in Table 1, when the content of comonomer gradually increases, the molecular weight will decrease, and the tensile strength of the corresponding POE copolymer will decrease.

[0196] As can be seen from Examples 1-5 and Comparative Example 3 in Table 1, when the side chains connected to the nitrogen atoms on the comonomer benzotriazole are short, the polymerization reaction will be severely affected, causing catalyst deactivation and making it impossible to obtain the copolymer.

[0197] Furthermore, as can be seen from Examples 1-5 and Comparative Example 4 in Table 1, different catalytic systems exhibit different tolerances to the light-converting agent monomer. The blended catalytic system of CGC catalyst and Ziegler-Natta catalyst, both commonly used in POE polymerization, is not suitable for the polymerization of light-converting POE molecules.

[0198] Furthermore, as can be seen from Examples 1-5 and Comparative Example 5, the traditional anti-migration method involves modifying the light-converting agent molecules and using the free radical cross-linking reaction in the later lamination process to prevent migration. The light-converting film prepared by this method does not have the problem of reaction efficiency, which leads to the residue of the light-converting agent. The residue of the light-converting agent has a significant impact on the encapsulation of perovskite solar cells. The preparation of light-converting POE significantly improves this defect and is of great significance for the encapsulation of perovskite solar cells.

Claims

1. A copolymer grafted with a light-converting agent, characterized in that, The copolymer includes repeating unit A. Repeating unit B and repeating unit C The ratio of the number of repeating units A, B and C is x:y:z, and x, y and z satisfy: y / (x+y) is 0.05~0.1, z / (x+y) is 0.0001~0.0008; In repeating unit B, R3 is selected from C2-C6 alkyl groups; In the repeating unit C, R1 and R2 are each independently selected from hydrogen atoms, C1-C5 alkyl, C1-C5 alkoxy, halogen atoms, trifluoromethyl, cyano and nitro; L is selected from C6-C10 alkylene; Ar1 ​​and Ar2 are each independently selected from unsubstituted C6-C20 aryl, substituted C6-C20 aryl, unsubstituted five- to twenty-membered heteroaryl and substituted five- to twenty-membered heteroaryl; The copolymer has a weight-average molecular weight of 20,000 to 60,000.

2. The copolymer according to claim 1, characterized in that, x and y satisfy the condition that y / (x+y) is 0.05~0.

07.

3. The copolymer according to claim 1, characterized in that, x, y, and z satisfy the following: z / (x+y) is 0.0001~0.0005; preferably, z / (x+y) is 0.0001~0.0002.

4. The copolymer according to claim 1, characterized in that, The copolymer has a weight-average molecular weight of 40,000 to 60,000, preferably 45,000 to 55,000, and more preferably 46,000 to 51,000.

5. The copolymer according to claim 1, characterized in that, The molecular weight distribution index of the copolymer is ≤5, preferably ≤3, for example 1~3.

6. The copolymer according to claim 1, characterized in that, In repeating unit B, R3 is selected from C2-C6 straight-chain alkyl groups, preferably from ethyl, n-butyl and n-hexyl, and more preferably n-hexyl.

7. The copolymer according to claim 1, characterized in that, In the repeating unit C, R1 and R2 are each independently selected from hydrogen atoms and C1-C5 alkyl groups, preferably from hydrogen atoms and methyl groups.

8. The copolymer according to claim 1, characterized in that, In the repeating unit C, L is selected from C6-C10 straight-chain alkylene groups, preferably from 1,6-hexene, 1,7-heptene, 1,8-octene, 1,9-nonene, and 1,10-decene.

9. The copolymer according to claim 1, characterized in that, In repeating unit C, the substituents on the substituted C6-C20 aryl group and the substituents on the substituted five- to twenty-membered heteroaryl group are each independently selected from C1-C5 alkyl, C1-C5 alkoxy, halogen atom, trifluoromethyl, cyano, nitro, -NR a R b , C6-C10 aryl and five- to twenty-membered heteroaryl groups, R a R b and R c Each is independently selected from H, C1-C5 alkyl and C6-C10 aryl.

10. The copolymer according to claim 1, characterized in that, In repeating unit C, Ar1 and Ar2 are each independently substituted phenyl groups, preferably phenyl groups substituted by 1-5 C1-C5 alkyl groups, more preferably phenyl groups substituted by 1 C1-C5 alkyl group at the para position, and preferably 4-tert-butyl-phenyl.

11. The copolymer according to claim 1, characterized in that, In repeating unit C, Ar1 and Ar2 are each independently selected from groups shown in Formulas 1 to 12: 。 12. A method for preparing the copolymer of claim 1, characterized in that, The method includes: reacting ethylene, a compound of formula III... Compounds of Formula II A copolymerization reaction occurs to obtain the copolymer; In Formula III, R3 is the same as R3 in repeating unit B in claim 1, and in Formula II, R1, R2, L, Ar1, and Ar2 are the same as R1, R2, L, Ar1, and Ar2 in repeating unit C in claim 1, respectively.

13. The method as described in claim 12, characterized in that, The catalyst used in the copolymerization reaction includes a main catalyst, which is... .

14. The method as described in claim 13, characterized in that, The amount of the main catalyst used is 0.5-5 μmol relative to 70 mL of compound of formula III.

15. The method as described in claim 13, characterized in that, The catalyst used in the copolymerization reaction also includes a co-catalyst, which is methylaluminoxane.

16. The method as described in claim 15, characterized in that, The molar ratio of the co-catalyst to the main catalyst is (200-5000):

1.

17. The method as described in claim 12, characterized in that, The copolymerization reaction is carried out at a pressure of 1.5-5 MPa and a temperature of 50-160 °C.

18. A light-converting adhesive film, characterized in that, The light-converting film comprises any one of claims 1-11.

19. The light-converting adhesive film as described in claim 18, characterized in that, The thickness of the light-converting film is 300-600 μm.

20. A solar cell module, characterized in that, The solar cell module includes solar cells and the light-converting adhesive film as described in claim 18 or 19.

21. The solar cell module as described in claim 20, characterized in that, The solar cell includes a perovskite light-absorbing layer.

22. The solar cell module as described in claim 20, characterized in that, The solar cell module also includes a front glass, and the light-converting adhesive film is located between the front glass and the solar cell.

23. A method for improving the power and / or reliability of a solar cell module, characterized in that, The method includes introducing the light-converting adhesive film of claim 18 or 19 between the front glass of the solar cell module and the cell.

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