Photovoltaic module comprising polyethylene encapsulating material

Abstract

The present invention relates to an encapsulated solar cell assembly comprising a solar cell between a first encapsulation layer and a second encapsulation layer, where the solar cell is positioned such that the first and second encapsulation layers are joined to fully encapsulate the solar cell, wherein each of the first and second sealant layers comprises or consists of a film or sheet of a polymer composition comprising: a) an ethylene-based copolymer; b) > = 0.1 wt% and < = 5.0 wt%, preferably > = 0.1 wt% and < = 1.0 wt%, of a crosslinking agent; c) > = 0.05 wt% and < = 5.0 wt%, preferably > = 0.05 wt% and < = 0.5 wt%, of a coupling agent, preferably a silane coupling agent; d) > = 0.05% and < = 5.0% by weight, preferably > = 0.05 and < = 1.0% by weight, of an auxiliary agent, preferably an auxiliary agent containing a phosphate moiety, an isocyanurate moiety or a cyanurate moiety; wherein all wt% are based on the total weight of the polymer composition; and wherein the ethylene-based copolymer has a vinyl unsaturation content of > = 6.0 / 105 carbon atoms, preferably > = 7.0 / 105 carbon atoms, preferably > = 12.0 / 105 carbon atoms, more preferably > = 12.0 and < = 20.0 / 105 carbon atoms, even more preferably > = 12.0 and < = 15.0 / 105 carbon atoms, when determined according to ASTM D6248-98 (2012). Such a solar cell module can be manufactured by a manufacturing method in which a desirably long initial stage in curing is achieved, thereby allowing flexibility of thermoplastic molding, desirably short curing time, thus reducing the cycle in the production of the packaged solar cell module while also resulting in a high degree of crosslinking of the packaging material.

Description

[0001] The present invention relates to a photovoltaic module comprising a solar cell encapsulated with a polymer composition. The present invention also relates to a method of manufacturing such a solar cell assembly.

[0002] The increasing use of photovoltaic systems as elements of a hybrid for sustainable energy generation solutions, particularly electricity generation systems, has created a need for high-quality, durable, and economically producible solar cell systems. Since these systems typically undergo relatively harsh climatic conditions and are continuously exposed to elements, it is important to provide the system with a suitably durable protective device.

[0003] In the sense of actually generating electricity upon exposure to sunlight, the photovoltaic elements, which are the functional part of such solar cell systems, are typically relatively fragile elements. To ensure that these elements are not damaged during the manufacture, transportation, installation, and ultimately operation of the solar cell, protective measures are typically employed, such as in the form of encapsulation that provides for the battery. Such encapsulation needs to provide proper adhesion to both the solar cell itself and to any front cover, which may be a glass cover sheet or a cover sheet of a polymeric material, such as a thermoplastic sheet, and to the rear protective or frame member. In addition, the encapsulation material needs to provide protection against moisture, air, mechanical shock, and vibration, and needs to provide good electrical isolation and heat creep resistance. In addition, there are also some requirements to be addressed related to the manufacture of solar cell systems, including the need for easy processing and short curing times.

[0004] Such encapsulation materials are typically provided in the form of a composition of thermoplastic materials, which can be applied to the solar cell as an encapsulation material, for example in the form of one or more films, which together encapsulate the solar cell, which then undergoes some curing or fixing process. Through such a curing process, the thermoplastic nature of the composition ceases to occur, and crosslinking occurs between the polymer molecules. Thus, such cured compositions will meet the above requirements related to providing durable protection for the solar cell assembly.

[0005] A particularly suitable class of thermoplastic materials for such encapsulation compositions is ethylene-based polymers. Ethylene-based polymers, particularly ethylene-based copolymers, are thermoplastic materials with a wide range of general uses and are among the most ubiquitous thermoplastic materials in the world. Also for encapsulation material solutions for solar cells, ethylene-based polymers can be a very suitable option, especially because of their inert nature.

[0006] However, there are still some needs for the ethylene-based polymer compositions described in the prior art. Specifically, in the manufacture of encapsulated solar cells, it is relevant that the curing or crosslinking of the encapsulant material composition (which involves heat treatment over a period of time) allows the initial stage of exposure of the composition to the curing temperature (which is the stage where the material absorbs the supplied heat but remains thermoplastically moldable) not to be too short to allow an appropriate window for thermoplastic forming; while on the other hand, the curing stage itself (which is the stage where crosslinking occurs) should preferably be short to allow for economical processing, which is defined by, for example, a desirably short cycle time. In addition, the degree of crosslinking should be desirably high.

[0007] According to the present invention, this can now be achieved by an encapsulated solar cell assembly comprising a solar cell located between a first sealing layer and a second sealing layer, wherein the solar cell is positioned such that the first sealing layer and the second sealing layer are joined to completely encapsulate the solar cell,

[0008] wherein each of the first sealing layer and the second sealing layer comprises or consists of a film or sheet of a polymer composition, the polymer composition comprising:

[0009] a) an ethylene-based copolymer;

[0010] b) a crosslinking agent in an amount of ≥ 0.1 wt% and ≤ 5.0 wt%, preferably ≥ 0.1 wt% and ≤ 1.0 wt%;

[0011] c) a coupling agent in an amount of ≥ 0.05 wt% and ≤ 5.0 wt%, preferably ≥ 0.05 wt% and ≤ 0.5 wt%, preferably a silane coupling agent;

[0012] d) an auxiliary agent in an amount of ≥ 0.05 wt% and ≤ 5.0 wt%, preferably ≥ 0.05 and ≤ 1.0 wt%, preferably an auxiliary agent containing a phosphate ester moiety, an isocyanurate moiety or a cyanurate moiety;

[0013] wherein all wt% are based on the total weight of the polymer composition; and

[0014] wherein the ethylene-based copolymer has an ethylenic unsaturation content of ≥ 6.0 / 10 5 carbon atoms, preferably ≥ 7.0 / 10 5 carbon atoms, preferably ≥ 12.0 / 10 5 carbon atoms, more preferably ≥ 12.0 and ≤ 20.0 / 10 5 carbon atoms, even more preferably ≥ 12.0 and ≤ 15.0 / 10 5 carbon atoms when determined according to ASTM D6248-98(2012).

[0015] Such a solar cell module can be produced by the following method, which allows for a desirably long initial stage during curing, thereby allowing flexibility in thermoplastic molding, a desirably short curing time, thus reducing the cycle in the production of the encapsulated solar cell module, and also resulting in a high degree of crosslinking of the encapsulation material.

[0016] Preferably, each of a), b), c) and d) is a different compound.

[0017] When measured according to ASTM D6248-98(2012), the ethylene-based polymer can have, for example, ≥5.0 / 10 5 carbon atoms, preferably ≥5.0 and ≤15.0 / 10 5 carbon atoms, more preferably ≥5.0 and ≤10.0 / 10 5 carbon atoms of vinylidene unsaturation content.

[0018] For example, when measured according to ASTM D6248-98(2012), when expressed as unsaturation / 10 5 carbon atoms, the vinylidene unsaturation content in the ethylene-based polymer can be greater than its vinylidene unsaturation content.

[0019] The ethylene-based polymer can have, for example, a unimodal chemical composition distribution. In the context of the present invention, a unimodal chemical composition distribution is understood as an elution profile showing a single peak in HPLC analysis.

[0020] Preferably, the ethylene-based copolymer is a non-polar polymer, such as a polymer that does not contain heteroatoms (especially oxygen) in its polymer structure.

[0021] Preferably, the polymer composition comprises ≥90.0 wt% of an ethylene-based copolymer, preferably ≥95.0 wt%, more preferably ≥98.0 wt%, based on the total weight of the polymer composition.

[0022] The ethylene-based polymer can have, for example, a density of ≥850 and ≤900 kg / m 3 measured according to ASTM D792(2008), preferably ≥860 and ≤890 kg / m 3 more preferably ≥865 and ≤885 kg / m 3 even more preferably ≥865 and ≤880 kg / m 3 of density.

[0023] The ethylene-based polymer is preferably a copolymer of ethylene and one or more α-olefins selected from the group consisting of 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene, with 1-octene being particularly preferred. The ethylene-based polymer preferably contains ≥55.0 wt% and ≤80.0 wt%, more preferably ≥60.0 and ≤70.0 wt%, of polymer structural parts derived from ethylene. The ethylene-based polymer preferably contains ≥20.0 and ≤45.0 wt%, more preferably ≥30.0 and ≤40.0 wt%, based on the total weight of the ethylene-based polymer, of polymer structural parts derived from 1-butene, 1-hexene, 4-methyl-1-pentene, or 1-octene, preferably 1-octene.

[0024] The ethylene-based polymer may, for example, have a melt mass flow rate of ≥2.0 and ≤25.0 g / 10 min, preferably ≥4.0 and ≤20.0 g / 10 min, more preferably ≥4.0 and ≤15.0 g / 10 min, as measured according to ASTM D1238 (2013) at 190 °C under a load of 2.16 kg.

[0025] The crosslinking agent may, for example, be selected from 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 3-di-tert-butyl peroxide, tert-cumyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne, dicumyl peroxide, α,α'-bis(tert-butylperoxyisopropyl)benzene, n-butyl-4,4-bis(tert-butylperoxy)butane, 2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butylperoxy)cyclohexane, tert-amylperoxy-2-ethylhexyl carbonate, tert-butylperoxy-2-ethylhexyl carbonate, tert-butylperoxybenzoate, 1,6-bis(tert-butylperoxycarbonyl)hexane, and combinations thereof, preferably selected from dicumyl peroxide, tert-amylperoxy-2-ethylhexyl carbonate, and tert-butylperoxy-2-ethylhexyl carbonate, more preferably selected from tert-amylperoxy-2-ethylhexyl carbonate and tert-butylperoxy-2-ethylhexyl carbonate.

[0026] The coupling agent may, for example, contain a silane structural part and at least one alkoxy structural part, preferably where the alkoxy structural part contains 1-5 carbon atoms; preferably the coupling agent contains three alkoxy structural parts, each of which contains 1-5 carbon atoms; more preferably, the coupling agent further contains a (meth)acrylate structural part.

[0027] For example, the coupling agent may be selected from γ-chloropropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl-tris-(p-methoxyphenyl)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-ethoxy-cyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-aminopropyltrimethoxysilane, preferably selected from vinyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane, more preferably γ-methacryloxypropyltrimethoxysilane.

[0028] The auxiliary agent may for example be a compound according to formula I:

[0029]

[0030]

[0031] wherein:

[0032] ● R1 is a trivalent structural moiety which is bonded to each R2 structural moiety via a heteroatom, preferably N or O; and

[0033] ● Each R2 is a structural moiety containing terminal vinyl unsaturation, preferably each R2 is a structural moiety containing 1 - 10 carbon atoms, more preferably each R2 is a linear structural moiety;

[0034] Preferably, each R2 is the same.

[0035] More preferably, each R2 is the same and is selected from vinyl, 2-propenyl, 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, and 7-octenyl.

[0036] Preferably, the compound of formula I is selected from:

[0037]

[0038] wherein each R3 is a structural moiety containing 1 - 5 carbon atoms, preferably wherein each R3 is a methyl, ethyl, n-propyl, isopropyl, n-butyl, or tert-butyl structural moiety, more preferably wherein each R3 is the same.

[0039] Particularly preferably, the auxiliary agent is selected from triallyl cyanurate, triallyl phosphate, triallyl isocyanurate, and 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane.

[0040] The polymer composition for use in the sealing layer of a solar cell module according to the present invention may for example be prepared by a method comprising the following steps:

[0041] ● Provide a composition comprising the following components to a mixing device, such as a melt extruder

[0042] o An ethylene-based polymer;

[0043] o A crosslinking agent in an amount of ≥ 0.1 wt% and ≤ 5.0 wt%, preferably ≥ 0.1 wt% and ≤ 1.0 wt%;

[0044] o A coupling agent in an amount of ≥ 0.05 wt% and ≤ 5.0 wt%, preferably ≥ 0.05 wt% and ≤ 0.5 wt%, preferably a silane coupling agent; and

[0045] o An additive in an amount of ≥ 0.05 wt% and ≤ 5.0 wt%, preferably ≥ 0.05 and ≤ 1.0 wt%, preferably an additive containing a phosphate structural moiety, an isocyanurate structural moiety or a cyanurate structural moiety;

[0046] And

[0047] ● Mix, such as extrude, the components at a melting temperature of ≤ 100 °C, preferably ≥ 80 °C and ≤ 100 °C to form a polymer composition.

[0048] A film for use as a sealing layer in a solar cell module according to the present invention can be prepared, for example, by a method comprising the following steps:

[0049] ● Provide a composition comprising the following components to a melt extruder

[0050] ● An ethylene-based polymer;

[0051] ● A crosslinking agent in an amount of ≥ 0.1 wt% and ≤ 5.0 wt%, preferably ≥ 0.1 wt% and ≤ 1.0 wt%;

[0052] ● A coupling agent in an amount of ≥ 0.05 wt% and ≤ 5.0 wt%, preferably ≥ 0.05 wt% and ≤ 0.5 wt%, preferably a silane coupling agent; and

[0053] ● An additive in an amount of ≥ 0.05 wt% and ≤ 5.0 wt%, preferably ≥ 0.05 and ≤ 1.0 wt%, preferably an additive containing a phosphate structural moiety, an isocyanurate structural moiety or a cyanurate structural moiety;

[0054] ● Extrude the components at a melting temperature of ≤ 100 °C to form an extrudate;

[0055] And

[0056] ● Cast the extrudate at a temperature of ≤ 100 °C to form a film.

[0057] The present invention also relates, in embodiments, to a cured solar cell module obtained by subjecting the encapsulated solar cell module of the present invention to conditions sufficient to cure the first and second sealing layers. Such conditions sufficient to cure the first and second sealing layers can be, for example, a temperature between 100 °C and 160 °C, preferably between 120 °C and 150 °C, for a period of time of ≥ 5 and ≤ 30 min, preferably ≥ 10 and ≤ 20 min.

[0058] The present invention also relates to a method for manufacturing a cured solar cell module, the method comprising the following steps:

[0059] a) providing a first sealing layer and a second sealing layer, and a solar cell, each of the first and second sealing layers comprising or consisting of a film that comprises a polymer composition, the polymer composition comprising:

[0060] ● an ethylene-based copolymer;

[0061] ● a crosslinking agent in an amount of ≥ 0.1 wt% and ≤ 5.0 wt%, preferably ≥ 0.1 wt% and ≤ 1.0 wt%;

[0062] ● a coupling agent in an amount of ≥ 0.05 wt% and ≤ 5.0 wt%, preferably ≥ 0.05 wt% and ≤ 0.5 wt%, preferably a silane coupling agent;

[0063] ● an auxiliary agent in an amount of ≥ 0.05 wt% and ≤ 5.0 wt%, preferably ≥ 0.05 and ≤ 1.0 wt%, preferably an auxiliary agent containing a phosphate moiety, an isocyanurate moiety or a cyanurate moiety;

[0064] wherein all wt% are based on the total weight of the polymer composition; and

[0065] wherein the ethylene-based copolymer has an ethylenic unsaturation content of ≥ 6.0 / 10 5 carbon atoms, preferably ≥ 7.0 / 10 5 carbon atoms, preferably ≥ 12.0 / 10 5 carbon atoms, more preferably ≥ 12.0 and ≤ 20.0 / 10 5 carbon atoms, even more preferably ≥ 12.0 and ≤ 15.0 / 10 5 carbon atoms when determined according to ASTM D6248-98(2012);

[0066] b) assembling the first sealing layer, the solar cell and the second sealing layer in such a way that the solar cell is completely encapsulated by the first and second sealing layers; and

[0067] c) Under conditions sufficient to cure the first and second encapsulation layers, preferably at a temperature between 100 °C and 160 °C, more preferably between 120 °C and 150 °C, for a period of ≥5 and ≤30 min, preferably ≥10 and ≤20 min, to cure the encapsulated solar cell module.

[0068] The present invention also relates to a photovoltaic module, comprising:

[0069] a) a front protective member;

[0070] b) a rear protective member; and

[0071] c) a cured solar cell module according to the present invention, wherein the cured solar cell module is located between the front protective member and the rear protective member.

[0072] The front protective member may be a transparent sheet, such as a glass sheet or a polymer sheet, which allows the required radiation to reach the solar cells in the solar cell module. The rear protective member may be formed by a frame structure for the photovoltaic module.

[0073] Figure 1 and 2 An example of a cross-section of a photovoltaic module is provided, which may be according to the present invention in its encapsulation material layer, where (1) represents the solar cell layer, each (2) represents the encapsulation material layer, (3) represents the front protective member, and (4) represents the rear protective member. In Figure 3 a decomposition view of such a photovoltaic module is provided, where each of the reference numerals (1)-(4) is identical to Figure 1 and Figure 2 the same.

[0074] The present invention will now be illustrated by the following non-limiting examples.

[0075] Material

[0076] In an embodiment according to the present invention, a polymer composition is prepared using the materials listed in Table 1 below.

[0077] Table 1: Materials

[0078] PE1 Ethylene-based polymer SABIC Fortify C13075DP PE2 Ethylene-based polymer SABIC Fortify C5075DP PE3 Ethylene-based polymer Dow Engage PV 8669 PE4 Ethylene-based polymer Dow Engage PV 8660 TBEC Crosslinking agent tert-Butyl peroxy 2-ethylhexyl carbonate, CAS Registry Number 3443-12-4 TAEC Crosslinking agent tert-Amyl peroxy 2-ethylhexyl carbonate, CAS Registry Number 70833-40-8 KH570 Coupling agent γ-Methacryloxypropyltrimethoxysilane, CAS Registry Number 2530-85-0 TAIC Auxiliary agent Triallyl isocyanurate, CAS Registry Number 1025-15-6

[0079] Ethylene-based polymers PE1-PE4 were analyzed to determine the properties and performance of the materials, and the results are provided in Table 2 below.

[0080] Table 2: Properties and characteristics of ethylene-based polymers

[0081] Performance PE1 PE2 PE3 PE4 Density 874 872 869 872 MFR2 14.6 4.9 13.7 4.6 C8 content 33.8 34.4 35.5 35.3 <![CDATA[M w > 67 87 70 91 <![CDATA[M n > 26 36 26 36 <![CDATA[M w / M n > 2.6 2.4 2.7 2.5 <![CDATA[M z > 120 155 135 175 <![CDATA[M z / M w > 1.8 1.8 1.9 1.9 <![CDATA[T p,m > 68.3 65.6 75.7 75.9 <![CDATA[T c > 49.2 48.4 53.9 53.2 Vinyl content 14 14 1 1 Vinylidene content 8 8 1 1

[0082] Wherein:

[0083] ● The density is determined according to ASTM D792 (2008) and is expressed in kg / m 3 ;

[0084] ● MFR2 is the melt mass flow rate, which is determined according to ASTM D1238 (2013) at 190 °C under a load of 2.16 kg and is expressed in g / 10 min;

[0085] ● The C8 content is the weight percentage of polymer units derived from 1-octene in the ethylene-based polymer, which is determined by 13 13C nuclear magnetic resonance on a Bruker Avance500 spectrometer equipped with a low-temperature cooling probe operating at 125 °C. Thus, the sample is dissolved in C2D2Cl4 containing DBPC as a stabilizer at 130 °C;

[0086] ● T p,m is the peak melting temperature determined by differential scanning calorimetry (DSC) according to ASTM D3418 (2008) and is expressed in °C;

[0087] ● T c is the crystallization temperature determined by differential scanning calorimetry (DSC) according to ASTM D3418 (2008) and is expressed in °C;

[0088] ● M n is the number-average molecular weight, M w is the weight-average molecular weight, and M z is the z-average molecular weight, where M n 、M w and M z are each expressed in kg / mol and are determined according to ASTM D6474 (2012);

[0089] ● The vinyl content and the vinylidene content are the amounts of each of vinyl unsaturation and vinylidene unsaturation, expressed in number of unsaturations / 100,000 chain carbon atoms, and are determined by 13 13C NMR on a Bruker Avance 500 spectrometer equipped with a low-temperature cooling probe operating at 125 °C. Thus, the sample is dissolved in C2D2Cl4 containing DBPC as a stabilizer at 130 °C.

[0090] In PE1-3, Figure 4Shows the elution profile obtained by HPLC analysis at 160 °C. Using a PolymerChar 2D-LC instrument, which has a Polymer Labs PL ELS1000 light scattering detector. HPLC elution was carried out at 160 °C at a flow rate of 1 mL / min. Using a Thermofischer Hypercarb column with a particle size of 7 μm, a length of 100 mm and an inner diameter of 4.6 mm. From this figure, it can be observed that PE1 and PE2 have a unimodal chemical composition distribution, as shown by the unimodal peak in this figure, while PE3 has a bimodal chemical composition distribution, as shown by the presence of two peaks in this figure.

[0091] Composition

[0092] Using the materials listed above, the compositions according to the following formulations were produced as follows: Mix the materials in a glass container, keep the mixture at room temperature for 12 hours, and then compress each composition into a polymer sheet with a thickness of 2 - 3 mm at 90 °C.

[0093] Table 3: Compositions

[0094] Example PE1 PE2 PE3 PE4 TBEC TAEC KH570 TAIC 1 50.0g 0.375g 0.15g 0.25g 2 50.0g 0.375g 0.15g 0.25g 3 50.0g 0.375g 0.15g 0.25g 4 50.0g 0.375g 0.15g 0.25g 5 50.0g 0.375g 0.15g 0.25g 6 50.0g 0.375g 0.15g 0.25g 7 50.0g 0.375g 0.15g 0.25g 8 50.0g 0.375g 0.15g 0.25g

[0095] For each of Examples 1 - 4, a curing test was carried out to obtain information on the crosslinking behavior of the composition. The compression-molded sheets obtained via the above method were subjected to curing at 145 °C for a period of 30 min, where the curing performance was determined according to ASTM D6601-12. This resulted in the torque performance shown in Table 4 below:

[0096] Table 4: Torque performance of compression-molded samples

[0097]

[0098]

[0099] In the table above, Examples 1 and 3 and 2 and 4 are particularly relevant to each other because the properties typically defining these products are similar for these combinations; in Examples 1 and 3, ethylene-based polymers of PE1 and PE3 were used respectively, and in Examples 2 and 4, ethylene-based polymers of PE2 and PE4 were used respectively. PE1 and PE3 have comparable MFR2 of about 14 g / 10 min and comparable M w , but they have different vinyl and vinylidene contents. The same applies to PE2 and PE4; they have similar MFR2 (about 5) and M w (about 90), but different vinyl and vinylidene contents.

[0100] The torque measurement results for each of Examples 1-4 are presented in Figure 5 .

[0101] From the results in Table 4, it can be observed that at the start of curing, as reflected by the value at 5 minutes, the torque value of Composition 1 was lower than that of Composition 3; the same applies to the comparison between Composition 2 and Composition 4. It can thus be concluded that the period of thermoplastic behavior at the start of curing according to the embodiments of the present invention is longer than that of the comparative examples. This is beneficial for the manufacturing process of encapsulated solar cell modules as it allows a longer period to have the flexibility to apply the encapsulating material to the solar cells.

[0102] Furthermore, it can be observed that at a curing time of 10 minutes, the torque value of Example 1 exceeded that of its equivalent Example 3, and the torque value of Example 2 exceeded that of its equivalent Example 4. It can thus be concluded that by using the compositions of Examples 1 and 2, the desired degree of curing or crosslinking can be achieved much faster at a given curing temperature, which is beneficial for the process efficiency of manufacturing solar cell modules; the production time can be reduced by using the compositions according to the present invention.

[0103] This can also be observed by measuring the gel content of the cured samples. Samples of the materials for each of Examples 1-4 were subjected to Soxhlet extraction to determine the gel content of the samples after being cured at 145 °C for 15 minutes. The values are listed in Table 5 below.

[0104] Table 5: Gel content of cured samples

[0105] Example 1 2 3 4 5 6 7 8 Gel content (%) 81 89 80 87 82 89 77 85

[0106] From Table 5, it can be observed that for both the group of examples (1-4) using TBEC as the crosslinking agent and the group of examples (5-8) using TAEC as the crosslinking agent, the gel content values of the compositions according to the present invention exceeded those of their corresponding comparative compositions.

Claims

1. An encapsulated solar cell module, said module comprising a solar cell located between a first sealing layer and a second sealing layer, wherein the solar cell is positioned such that the first sealing layer and the second sealing layer are joined to completely encapsulate the solar cell, wherein each of the first sealing layer and the second sealing layer comprises or consists of a film or sheet of a polymer composition, the polymer composition comprising: a) An ethylene-based copolymer; b) A crosslinking agent of ≥0.1% by weight and ≤5.0% by weight, preferably ≥0.1% by weight and ≤1.0% by weight; c) A coupling agent of ≥0.05% by weight and ≤5.0% by weight, preferably ≥0.05% by weight and ≤0.5% by weight, preferably a silane coupling agent; d) An auxiliary agent of ≥0.05% by weight and ≤5.0% by weight, preferably ≥0.05 and ≤1.0% by weight, preferably an auxiliary agent containing a phosphate structural moiety, an isocyanurate structural moiety or a cyanurate structural moiety; wherein all percentages by weight are based on the total weight of the polymer composition; and wherein when measured according to ASTM D6248-98(2012), the ethylene-based copolymer has a vinyl unsaturation content of ≥6.0 / 10 5 carbon atoms, preferably ≥7.0 / 10 5 carbon atoms, preferably ≥12.0 / 10 5 carbon atoms, more preferably ≥12.0 and ≤20.0 / 10 5 carbon atoms, even more preferably ≥12.0 and ≤15.0 / 10 5 carbon atoms.

2. The solar cell module according to claim 1, wherein when measured according to ASTM D6248-98(2012), the ethylene-based polymer has a vinylidene unsaturation content of ≥5.0 / 10 5 carbon atoms, preferably ≥5.0 and ≤15.0 / 10 5 carbon atoms, more preferably ≥5.0 and ≤10.0 / 10 5 carbon atoms.

3. The solar cell module according to any one of claims 1-2, wherein when measured according to ASTM D6248-98(2012), when expressed as the degree of unsaturation / 10 5 carbon atoms, the vinyl unsaturation content of the ethylene-based polymer is greater than its vinylene unsaturation content.

4. The solar cell module according to any one of claims 1-3, wherein ● The ethylene-based polymer has a unimodal chemical composition distribution; and / or ● The ethylene-based copolymer is a non-polar polymer; and / or ● The composition comprises ≥90.0% by weight of the ethylene-based copolymer based on the total weight of the polymer composition; and / or ● The ethylene-based polymer has a density of ≥ 850 and ≤ 900 kg / m3 as measured according to ASTM D792 (2008), 3 preferably ≥ 865 and ≤ 885 kg / m3. 3 ​ 5. The solar cell module according to any one of claims 1-4, wherein ● The ethylene-based polymer is a copolymer of ethylene and one or more α-olefins selected from: 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene, preferably 1-octene; and / or ● The ethylene-based polymer comprises ≥55.0% by weight and ≤80.0% by weight, preferably ≥60.0 and ≤70.0% by weight of polymer structural moieties derived from ethylene, and / or wherein the ethylene-based polymer comprises ≥20.0 and ≤45.0% by weight, preferably ≥30.0 and ≤40.0% by weight based on the total weight of the ethylene-based polymer of polymer structural moieties derived from 1-butene, 1-hexene, 4-methyl-1-pentene or 1-octene, preferably 1-octene; and / or ● The ethylene-based polymer has a melt mass flow rate of ≥2.0 and ≤25.0 g / 10 min, preferably ≥4.0 and ≤20.0 g / 10 min, more preferably ≥4.0 and ≤15.0 g / 10 min as measured at 190 °C under a load of 2.16 kg according to ASTM D1238 (2013).

6. The solar cell module according to any one of claims 1-5, wherein the crosslinking agent is selected from 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 3-di-tert-butyl peroxide, tert-butyl cumyl peroxide, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne, dicumyl peroxide, α,α'-bis(tert-butylperoxyisopropyl)benzene, n-butyl-4,4-bis(tert-butylperoxy)butane, 2,2-bis(tert-butylperoxy)butane, 1,1-bis(tert-butylperoxy)cyclohexane, tert-amylperoxy-2-ethylhexyl carbonate, tert-butylperoxy-2-ethylhexyl carbonate, tert-butylperoxybenzoate, 1,6-bis(tert-butylperoxycarbonyl)hexane, and combinations thereof, preferably selected from dicumyl peroxide, tert-amylperoxy-2-ethylhexyl carbonate, and tert-butylperoxy-2-ethylhexyl carbonate, more preferably selected from tert-amylperoxy-2-ethylhexyl carbonate and tert-butylperoxy-2-ethylhexyl carbonate.

7. The solar cell module according to any one of claims 1-6, wherein the coupling agent comprises a silane structural moiety and at least one alkoxy structural moiety, preferably wherein the alkoxy structural moiety contains 1-5 carbon atoms; preferably wherein the coupling agent comprises three alkoxy structural moieties, each of which contains 1-5 carbon atoms; more preferably, wherein the coupling agent further comprises a (meth)acrylate structural moiety.

8. The solar cell module according to any one of claims 1-7, wherein the coupling agent is selected from γ-chloropropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyl-tris(p-methoxyphenyl)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-ethoxy-cyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and γ-aminopropyltrimethoxysilane, preferably selected from vinyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane, more preferably γ-methacryloxypropyltrimethoxysilane.

9. The solar cell module according to any one of claims 1-8, wherein the auxiliary agent is a compound according to formula I: Wherein: ● R1 is a trivalent structural moiety that is bonded to each R2 structural moiety via a heteroatom, preferably N or O; and ● Each R2 is a structural moiety containing terminal vinyl unsaturation, preferably each R2 is a structural moiety containing 1-10 carbon atoms, more preferably each R2 is a linear structural moiety; Preferably wherein each R2 is the same, more preferably wherein each R2 is the same and is selected from vinyl, 2-propenyl, 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, and 7-octenyl.

10. The solar cell module according to claim 9, wherein the compound of formula I is selected from: Each R3 is a structural moiety containing 1 to 5 carbon atoms, preferably each R3 is a methyl, ethyl, n-propyl, isopropyl, n-butyl or tert-butyl structural moiety, more preferably each R3 is the same.

11. The solar cell module according to any one of claims 1-10, wherein the auxiliary agent is selected from triallyl cyanurate, triallyl phosphate, triallyl isocyanurate, and 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane.

12. A cured solar cell module obtained by subjecting the encapsulated solar cell module according to any one of claims 1-11 to conditions sufficient to cure the first sealing layer and the second sealing layer.

13. The cured solar cell module according to claim 12, wherein the conditions sufficient to cure the first sealing layer and the second sealing layer are a temperature between 100 °C and 160 °C, preferably between 120 °C and 150 °C, for a period of ≥5 and ≤30 min, preferably ≥10 and ≤20 min.

14. A method for manufacturing a cured solar cell module, the method comprising the following steps: a) providing a first sealing layer and a second sealing layer, and a solar cell, each of the first sealing layer and the second sealing layer comprising or consisting of a film, the film comprising a polymer composition, the polymer composition comprising: ● an ethylene-based copolymer; ● a crosslinking agent in an amount of ≥0.1 wt% and ≤5.0 wt%, preferably ≥0.1 wt% and ≤1.0 wt%; ● a coupling agent in an amount of ≥0.05 wt% and ≤5.0 wt%, preferably ≥0.05 wt% and ≤0.5 wt%, preferably a silane coupling agent; ● an auxiliary agent in an amount of ≥0.05 wt% and ≤5.0 wt%, preferably ≥0.05 and ≤1.0 wt%, preferably an auxiliary agent containing a phosphate structure moiety, an isocyanurate structure moiety or a cyanurate structure moiety; wherein all weight percentages are based on the total weight of the polymer composition; and wherein when measured according to ASTM D6248-98(2012), the ethylene-based copolymer has a vinyl unsaturation content of ≥6.0 / 10 5 carbon atoms, preferably ≥7.0 / 10 5 carbon atoms, preferably ≥12.0 / 10 5 carbon atoms, more preferably ≥12.0 and ≤20.0 / 10 5 carbon atoms, even more preferably ≥12.0 and ≤15.0 / 10 5 carbon atoms; b) assembling the first sealing layer, the solar cell and the second sealing layer such that the solar cell is completely encapsulated by the first sealing layer and the second sealing layer; and c) curing the encapsulated solar cell module under conditions sufficient to cure the first sealing layer and the second sealing layer, preferably at a temperature between 100 °C and 160 °C, more preferably between 120 °C and 150 °C, for a period of ≥5 and ≤30 min, preferably ≥10 and ≤20 min.

15. A photovoltaic module comprising: a) a front protective member; b) a rear protective member; and c) the cured solar cell module according to any one of claims 12-13, wherein the cured solar cell module is located between the front protective member and the rear protective member.

Images