Functional photovoltaic adhesive film, preparation method thereof and photovoltaic module

Abstract

The application provides a functional photovoltaic adhesive film, a preparation method thereof and a photovoltaic module. The raw material formula of the functional photovoltaic adhesive film comprises a base resin, a light stabilizer, a main crosslinking agent, an auxiliary crosslinking agent, a coupling agent and a functional additive. The functional additive is rhodamine-polyether-silane. The formula of the functional photovoltaic adhesive film is simple, and the functional additive has multiple functions. The functional additive can stably endow the photovoltaic module with excellent ultraviolet aging resistance for a long time while improving the high PID resistance of the module, so that the module has excellent power generation and service life.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology and relates to a functional photovoltaic encapsulant film, particularly a functional photovoltaic encapsulant film with high resistance to PID, resistance to ultraviolet aging, long-term stability, simple additive formulation, and low addition amount, as well as its preparation method. Background Technology

[0002] Photovoltaic encapsulant film is one of the core materials of photovoltaic modules, mainly including ethylene-vinyl acetate (EVA) encapsulant film, ethylene-α-olefin copolymer (POE) encapsulant film, and EPE encapsulant film which integrates the characteristics of both. With continuous optimization by downstream manufacturers, modified photovoltaic encapsulant films incorporating a second or third component resin into the base resin have emerged in recent years. This is because when POE encapsulant film is used alone, its branched alkane chains, which mainly lack polar groups, result in poor absorption of additives, leading to problems such as additive precipitation, cell slippage, and slow cross-linking and vulcanization during use. Conversely, when EVA encapsulant film is used alone, the presence of hydrophilic polar groups and acidic substances after hydrolysis in its structure leads to problems such as high water vapor permeability, poor PID resistance of the module, and cell corrosion during use.

[0003] Therefore, various manufacturers and researchers have conducted a series of studies from different dimensions, including encapsulant composition, formulation, and processes. In particular, with the continuous development of battery technology in recent years, the industry has launched new types of batteries known for their high efficiency, such as TOPcon, HJT, and perovskite batteries. However, due to the characteristics of the battery cell's technical route and process, certain problems still exist, such as: TOPcon batteries have poor anti-PID performance on the front side; HJT batteries require high adhesive strength from the encapsulant film; both the battery cell and backsheet are easily damaged by UV light; and perovskite batteries require materials with high water vapor barrier properties for encapsulation. Therefore, downstream encapsulant film manufacturers need to continuously optimize and upgrade their encapsulant film formulations to adapt to the development of photovoltaic cells and encapsulation technologies.

[0004] Typically, encapsulant film formulations require the addition of basic additives such as crosslinking agents, co-crosslinking agents, light stabilizers, and coupling agents. To adapt to the characteristics of the aforementioned solar cells, some manufacturers also add additional additives such as anti-PID agents, anti-exudation agents, and light conversion agents. Patent CN114806422B adds the UV absorber p-dimethylaminocinnamoxypropyltrimethoxysilane and inorganic nano-oxides to the formulation to enhance the UV cutoff capability of the encapsulant film module. CN111662655A adds porous materials or cage-like compounds to the formulation to improve the anti-exudant exudation capability of the encapsulant film. CN116042134A proposes a multifunctional encapsulant film that combines UV light absorption, UV light conversion, and high film-cell adhesion; however, its formulation is complex, with additional additives such as UV light conversion agents, UV absorbers, polymerization inhibitors, and tackifiers. The more additives are added, the easier it is for them to precipitate in the matrix resin. At the same time, the introduction of a large amount of additives can plasticize the matrix resin material, which will also reduce the mechanical properties of the material to some extent.

[0005] Against this background, this invention proposes a method for preparing multifunctional photovoltaic encapsulant films based on the structure-activity relationship of formulation additives. This method simplifies the encapsulant film formulation and reduces the amount of additives required. While improving the high PID resistance performance of the module, the functional additives can provide the photovoltaic module with excellent UV aging resistance over a long period of time, resulting in excellent power generation and service life. Summary of the Invention

[0006] One objective of this invention is to propose a functional photovoltaic film that combines high resistance to PID, resistance to UV aging, long-term stability, simple additive formulation, and low addition amount.

[0007] Another object of the present invention is to provide a solar cell module comprising the adhesive film.

[0008] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0009] A functional photovoltaic encapsulant film comprises the following raw materials in parts by weight:

[0010]

[0011]

[0012] Preferably, the base resin is one or more of the following: ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-butyl acrylate copolymer (EBA), polyolefin elastomer (POE), polyvinyl butyral (PVB), and olefin block copolymer (OBC).

[0013] Preferably, the light stabilizer is selected from one or more combinations of 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol, bis(2,2,6,6,-tetramethyl-4-piperidinyl) sebacate or polysuccinate (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol);

[0014] Preferably, the main crosslinking agent is selected from one or any combination of several of the following: di(4-methylbenzoyl)peroxide, cumene peroxide, 2,2-bis(tert-butyl peroxide)butane, dicumene hydrogen peroxide, 2,5-dimethyl-2,5-di-tert-butyl peroxide, tert-butyl peroxyhexyl carbonate, benzoyl peroxide, cyclohexanone peroxide, tert-butyl peracetate, tert-butyl peroxybenzoate, and tert-butyl peroxide-3,5,5-trimethylhexanoate.

[0015] The crosslinking agent is selected from one or any combination of triallyl isocyanurate, trimethylolpropane triacrylate, triallyl cyanurate and trimethylolpropane trimethacrylate.

[0016] Preferably, the coupling agent is a silane coupling agent selected from one or more of the following: methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, vinyltriethoxysilane, vinyltriperoxytert-butylsilane, γ-methacryloyloxypropyltrimethoxysilane, 3-glycidylpropyltrimethoxysilane, 3-aminopropyltriethoxysilane, or vinylalkoxysilane oligomers.

[0017] Preferably, the functional additive is a low molecular weight polymer of rhodamine-polyether-silane (Rhodamine-PE-R-Silane) as shown below, with a weight-average molecular weight preferably of 1000-3000 g / mol. The polyether segment PE is selected from one or more combinations of polyethylene glycol segments, polypropylene glycol segments, or polybutane segments. The silane segment Silane is selected from one or more combinations of trimethoxysilane, triethoxysilane, triperoxytert-butylsilane, triacetoxysilane, and tris(β-methoxyethoxy)silane. The connecting segment R between the polyether segment PE and the silane segment Silane is selected from one or more combinations of epoxy, vinyl, acrylate, methacryloxy, mercapto, hydroxy, amino, alkynyl, or urea groups.

[0018]

[0019] A method for preparing the aforementioned functional photovoltaic encapsulant film includes the following preparation steps:

[0020] Step S1: Mix the base resin, light stabilizer, main crosslinking agent, co-crosslinking agent, coupling agent, and functional additives evenly to obtain the formulation mixture;

[0021] Step S2: The formula mixture is added to an extrusion device and cast extrusion is performed at a temperature of 70-120°C to obtain the functional photovoltaic film.

[0022] This invention also relates to the application of the aforementioned functional photovoltaic encapsulant film in the preparation of photovoltaic modules. For example, a photovoltaic module includes a front panel, a first encapsulant film, solar cells, a second encapsulant film, and a back panel stacked sequentially, wherein the first encapsulant film and / or the second encapsulant film are the aforementioned functional photovoltaic encapsulant films.

[0023] The beneficial effects of this invention are as follows:

[0024] The multifunctional photovoltaic encapsulant film of this invention, with its rhodamine-polyether-silane structure, has the following functions: ① The rhodamine structure can convert high-energy light that is destructive to the solar cell into low-energy light that can be absorbed and utilized by the solar cell, thus protecting the solar cell, extending the lifespan of the module, and generating higher power generation efficiency, achieving the effect of a light conversion additive; ② The polyether structure contains a large number of lone pairs of electrons, which can adsorb metal cations, allowing the metal cations to be conducted along the molecular chain under the action of potential difference. At the same time, the lone pairs of electrons form hydrogen bonds with water, thereby reducing the amount of water entering the surface of the solar cell, ultimately enabling the solar cell to have higher power generation, achieving the effect of anti-PID additive; ③ The silane structure allows this type of functional additive to exist permanently and reliably in the photovoltaic encapsulant film without migrating or precipitating, thus giving the photovoltaic encapsulant film a stable and long-lasting anti-PID and UV light conversion effect, while also achieving the effect of preventing the precipitation of additives;

[0025] The functional photovoltaic encapsulant film provided by this invention has a simple formulation and requires a small amount of additives. While improving the high anti-PID performance of the module, the functional additives provide the photovoltaic module with excellent resistance to ultraviolet aging in a long-term and stable manner, enabling the module to have excellent power generation and service life. Detailed Implementation

[0026] The present invention will be further described below through specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention. In this application, "parts" and "%" are by weight unless otherwise specified.

[0027] Main materials:

[0028] Base resins: POE resin, Dow, 8660; EVA resin, Sirbon, 2825;

[0029] Light stabilizers: bis(2,2,6,6,-tetramethyl-4-piperidinyl) sebacate, Tianjin Lianlong New Material Co., Ltd., purity 98%; 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol, Tianjin Zhongxin Kaitai Chemical Co., Ltd., purity 98%;

[0030] Main crosslinking agents: tert-butyl peroxide, Beijing Bailingwei Technology Co., Ltd., purity 98%; 2,2-bis(tert-butyl peroxide)butane, Beijing Bailingwei Technology Co., Ltd., purity 98%; tert-butyl peroxide, Beijing Bailingwei Technology Co., Ltd., purity 95%.

[0031] Crosslinking agent: triallyl isocyanurate, Shanghai Maclean Biochemical Technology Co., Ltd., purity 98%; trimethylolpropane triacrylate, Yantai Hengnuo New Materials Co., Ltd., purity 98%;

[0032] Coupling agents: Vinyltriethoxysilane, Shanghai Maclean Biochemical Technology Co., Ltd., purity 97%; 3-glycidylpropyltrimethoxysilane, Shanghai Mairui Biochemical Technology Co., Ltd., purity 97%; γ-(2,3-epoxypropoxy)propyltrimethoxysilane, Shanghai Aladdin Biochemical Technology Co., Ltd., purity 97%.

[0033] Functional additive: Rhodamine-polyethylene glycol-triethoxysilane, weight average molecular weight 1500 g / mol, Yusi Pharmaceutical, purity 90%, chemical structure shown below;

[0034]

[0035] UV light transfer agent: Rhodamine B, Inokai, purity > 95%;

[0036] PERC battery, Tongwei 182 bifacial battery.

[0037] Test instruments and methods:

[0038] The extruder is a single-screw extruder (L / D = 35), with a screw diameter of 30 mm;

[0039] PID equipment: Shanghai Quality and Health Environmental Chamber, model EW-EC03PID02-021220. The prepared double-glass photovoltaic modules were subjected to PID resistance tests under the conditions of 96h-85℃ / 85RH / -1500V.

[0040] Power testing equipment: Nanjing Lixite, model LXT-CELL;

[0041] UV aging chamber: Optoelectronics Aipei Technology, model AP-UV;

[0042] Universal Mechanical Testing Instrument: INSTRON, 5980;

[0043] The prepared adhesive film was tested for peel strength between the adhesive film and the backing plate under UV 60kw·h conditions using a universal testing instrument according to GB / T 29848-2018.

[0044] Light transmittance test:

[0045] The prepared films were tested according to the spectrophotometer method in GB / T 29848-2018, and the average transmittance in the wavelength ranges of 290nm~380nm and 380nm~1100nm was calculated respectively.

[0046] Examples and comparative examples:

[0047] Example 1

[0048] Add 9g of tert-butyl peroxide, 5g of triallyl isocyanurate, 2g of vinyltriethoxysilane, 2g of bis(2,2,6,6,-tetramethyl-4-piperidinyl) sebacate, and 10g of rhodamine-polyethylene glycol-triethoxysilane to 1000g of POE 8660. Heat the above raw materials to 50℃ and mix them evenly. Adjust the extruder parameters: the temperature from the feed nozzle to the die head is 80℃, 90℃, 90℃, 90℃, 90℃, 95℃, 95℃, 95℃; the screw speed is 45rpm; the traction speed is 0.7rpm; and the winding speed is 1.3rpm. After extrusion, casting, cooling, slitting, and winding processes, a photovoltaic module encapsulation film with a thickness of 0.6mm is prepared.

[0049] Tempered glass, encapsulating film, crystalline silicon solar cells, encapsulating film, and float glass are placed in the order from top to bottom and laminated at 145°C using a laminator to obtain a double-glass photovoltaic module.

[0050] Example 2

[0051] Add 8g of 2-ethylhexyl carbonate tert-butyl peroxide, 4g of trimethylolpropane triacrylate, 5g of 3-glycidylpropyltrimethoxysilane, 3g of 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol, and 12g of rhodamine-polyethylene glycol-triethoxysilane to 1000g of EVA 2825. Heat the above raw materials to 50°C and mix them evenly. Adjust the extruder parameters: the temperature from the feed nozzle to the die head is 80°C, 90°C, 90°C, 90°C, 90°C, 95°C, 95°C, 95°C; the screw speed is 48 rpm; the traction speed is 0.6 rpm; and the winding speed is 1.2 rpm. After extrusion, casting, cooling, slitting, and winding processes, a photovoltaic module encapsulation film with a thickness of 0.6 mm is prepared.

[0052] Double-glass photovoltaic modules were prepared using the same method as in Example 1.

[0053] Example 3

[0054] Add 15g of 2,2-bis(tert-butylperoxide)butane, 10g of triallyl isocyanurate, 4g of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, 4g of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and 15g of rhodamine-polyethylene glycol-triethoxysilane to 1000g of POE 8660. Heat the above raw materials to 50°C and mix them evenly. Adjust the extruder parameters as follows: the temperature from the feed nozzle to the die head is 80°C, 90°C, 90°C, 90°C, 90°C, 95°C, 95°C, 95°C; the screw speed is 48 rpm; the traction speed is 0.7 rpm; and the winding speed is 1.3 rpm. After extrusion, casting, cooling, slitting, and winding processes, a photovoltaic module encapsulation film with a thickness of 0.65mm is prepared.

[0055] Double-glass photovoltaic modules were prepared using the same method as in Example 1.

[0056] Comparative Example 1

[0057] Add 9g of tert-butyl peroxide, 5g of triallyl isocyanurate, 2g of vinyltriethoxysilane, and 2g of bis(2,2,6,6,-tetramethyl-4-piperidinyl) sebacate to 1000g of POE 8660.

[0058] The encapsulation film and double-glass photovoltaic module were prepared using the same method as in Example 1.

[0059] Comparative Example 2

[0060] Add 9g tert-butyl peroxide, 5g triallyl isocyanurate, 2g vinyltriethoxysilane, 2g bis(2,2,6,6,-tetramethyl-4-piperidinyl) sebacate, and 10g rhodamine B to 1000g POE 8660.

[0061] The encapsulation film and double-glass photovoltaic module were prepared using the same method as in Example 1.

[0062] Example and comparative test results:

[0063]

[0064] A comparison of the performance test data of the embodiments and comparative examples described in the table above shows that:

[0065] The functional photovoltaic encapsulating film of this invention, when used to manufacture photovoltaic modules, significantly improves the anti-PID performance of the encapsulated modules. Simultaneously, the addition of functional additives greatly enhances the backsheet's resistance to UV aging. In Comparative Example 1, since no light conversion additive was added, the transmittance was significantly increased in the 290-380nm wavelength range. Meanwhile, the peel strength values ​​after UV aging for Comparative Example 2 and Comparative Example 1 were similar, but significantly lower than those for Examples 1-3. This indicates that the light conversion agent Rhodamine B molecules in Comparative Example 2 did not remain permanently immobilized in the film, leading to photoaging of the backsheet under UV light and a decrease in peel strength.

[0066] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A functional photovoltaic encapsulant film, characterized in that, The ingredients include the following parts by weight: 85-100 parts of base resin, Light stabilizer 0.1 to 1 part, 0.1-2 parts of main crosslinking agent, Crosslinking agent 0.05-1 part, Coupling agent 0.05-1 part, Functional additives: 0.5–3 parts; in: The base resin is one or more of the following: ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methacrylic acid copolymer (EMAA), ethylene-butyl acrylate copolymer (EBA), polyolefin elastomer (POE), polyvinyl butyral (PVB), and olefin block copolymer (OBC). The functional additive is a low molecular weight polymer of rhodamine-polyether-silane as shown below, wherein PE is a polyether segment selected from one or more combinations of polyethylene glycol segments, polypropylene glycol segments, or polybutane segments; Silane is a silane segment selected from one or more combinations of trimethoxysilane, triethoxysilane, triperoxytert-butylsilane, triacetoxysilane, and tris(β-methoxyethoxy)silane; and the connecting segment R between the polyether segment PE and the silane segment Silane is selected from one or more combinations of epoxy, vinyl, acrylate, methacryloxy, mercapto, hydroxy, amino, alkynyl, or urea groups. 。 2. The functional photovoltaic encapsulant film according to claim 1, characterized in that, The weight-average molecular weight of the functional additive is 1000–3000 g / mol.

3. The functional photovoltaic encapsulant film according to claim 1, characterized in that, The light stabilizer is selected from one or more combinations of 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol, bis(2,2,6,6,-tetramethyl-4-piperidinyl) sebacate or polysuccinate (4-hydroxy-2,2,6,6-tetramethyl-1-piperidinol).

4. The functional photovoltaic encapsulant film according to claim 1, characterized in that, The main crosslinking agent is selected from one or any combination of several of the following: di(4-methylbenzoyl)peroxide, tert-butyl peroxide, cumene peroxide, 2,2-bis(tert-butyl peroxide)butane, dicumene hydrogen peroxide, 2,5-dimethyl-2,5-di-tert-butyl peroxide, tert-butyl peroxy-2-ethylhexyl carbonate, benzoyl peroxide, cyclohexanone peroxide, tert-butyl peracetate, and tert-butyl peroxide-3,5,5-trimethylhexanoate.

5. The functional photovoltaic encapsulant film according to claim 1, characterized in that, The crosslinking agent is selected from one or any combination of triallyl isocyanurate, trimethylolpropane triacrylate, triallyl cyanurate and trimethylolpropane trimethacrylate.

6. The functional photovoltaic encapsulant film according to claim 1, characterized in that, The coupling agent is a silane coupling agent.

7. A functional photovoltaic encapsulant film according to claim 6, characterized in that, The coupling agent is selected from one or more of the following: methacryloyloxypropyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, vinyltriethoxysilane, vinyltriperoxytert-butylsilane, γ-methacryloyloxypropyltrimethoxysilane, 3-glycidylpropyltrimethoxysilane, 3-aminopropyltriethoxysilane, or vinylalkoxysilane oligomers.

8. A method for preparing a functional photovoltaic encapsulant film according to any one of claims 1-7, characterized in that, The preparation steps include the following: Step S1: Mix the base resin, light stabilizer, main crosslinking agent, co-crosslinking agent, coupling agent, and functional additives evenly to obtain the formulation mixture; Step S2: The formula mixture is added to an extrusion device and cast extrusion is performed at a temperature of 70-120°C to obtain the functional photovoltaic film.

9. The application of a functional photovoltaic encapsulant film according to any one of claims 1-7 in the preparation of photovoltaic modules.

10. A photovoltaic module, comprising a front panel, a first encapsulating film, solar cells, a second encapsulating film, and a back panel stacked sequentially, characterized in that, The first encapsulating film and / or the second encapsulating film are functional photovoltaic encapsulating films as described in any one of claims 1-7.

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