Polymer composition for solar cell modules

Abstract

The present invention relates to 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) more than or equal to 0.05 wt% and less than or equal to 5.0 wt%, preferably more than or equal to 0.05 wt% and less than or equal to 1.0 wt% 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 ASTMD6248-98 (2012). Such a polymer composition allows a desirably long initial stage in curing, thereby allowing flexibility in thermoplastic molding, desirably short curing period, thereby reducing the cycle in the production of packaged solar cell modules while also achieving high degree of crosslinking of the packaging material.

Description

[0001] The present invention relates to a polymer composition which is suitable for use in a solar cell module, in particular for use in an encapsulation material system for solar cells in such a module. Specifically, the present invention relates to a polymer composition comprising an ethylene-based polymer which can be used in such an encapsulation material system.

[0002] The increasing use of photovoltaic systems as elements of a hybrid for sustainable energy generation solutions, in particular for electricity generation systems, has created a need for high-quality, durable and economically producible solar cell systems. Since these systems are typically subjected to 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 generally relatively fragile elements. To ensure that these elements are not damaged during the manufacture, transportation, installation and ultimately the operation of the solar cells, protective measures are typically employed, such as in the form of encapsulation provided for the cells. Such encapsulation needs to provide suitable adhesion to both the solar cell itself and to any front cover, which can be a glass cover sheet or a cover sheet of polymeric material, such as a thermoplastic sheet, and 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 insulation and heat creep resistance. Furthermore, there are certain requirements to be addressed in relation 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 cells as an encapsulation material, for example in the form of one or more films which together encapsulate the solar cells and which subsequently undergo certain curing or fixing processes. 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 solar cell modules.

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

[0006] However, there are still certain 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 encapsulating 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) to not be too short to allow for 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] This can now be achieved by applying the polymer composition of the present invention, which comprises:

[0008] a) An ethylene-based copolymer;

[0009] b) A crosslinking agent in an amount of ≥0.1 wt% and ≤5.0 wt%, preferably ≥0.1 wt% and ≤1.0 wt%;

[0010] 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;

[0011] d) An auxiliary agent in an amount of ≥0.05 wt% and ≤5.0 wt%, preferably ≥0.05 wt% and ≤1.0 wt%, preferably an auxiliary agent containing a phosphate structural moiety, an isocyanurate structural moiety or a cyanurate structural moiety;

[0012] wherein all wt% are based on the total weight of the polymer composition; and

[0013] wherein when determined according to ASTM D6248-98(2012), the vinyl unsaturation content of the ethylene-based copolymer is ≥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.

[0014] Such a polymer composition allows for a desirably long initial stage during curing, thus allowing flexibility in thermoplastic molding, a desirably short curing period, thereby reducing the cycle in the production of encapsulated solar cell modules, while also achieving a high degree of crosslinking of the encapsulating material.

[0015] When measured according to ASTM D6248-98(2012), the vinylidene unsaturation content of an ethylene-based polymer can be ≥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.

[0016] For example, when measured according to ASTM D6248-98(2012), when expressed as unsaturation / 10 5 carbon atoms, the vinyl unsaturation content in the ethylene-based polymer can be greater than its vinylidene unsaturation content.

[0017] In certain embodiments, when measured according to ASTM D6248-98(2012), the vinyl unsaturation content of the ethylene-based copolymer is ≥12.0 and ≤20.0 / 10 5 carbon atoms, preferably ≥12.0 and ≤15.0 / 10 5 carbon atoms. Using such an ethylene-based copolymer in a polymer composition provides the desired curing behavior of the encapsulating material and the desired high degree of crosslinking of the phase combination, while reducing undesired degradation during the service life of the final product.

[0018] The ethylene-based polymer can, for example, have a unimodal chemical composition distribution. In the context of the present invention, a unimodal chemical composition distribution is understood to mean that in HPLC analysis, the elution profile shows a single peak.

[0019] Preferably, the ethylene-based copolymer is a non-polar polymer, for example a polymer that does not contain heteroatoms, especially oxygen, in its polymerization structure.

[0020] 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.

[0021] When measured according to ASTM D792(2008), the density of the ethylene-based polymer is, for example, ≥850 and ≤900 kg / m 3 , preferably ≥860 and ≤890 kg / m 3 , more preferably ≥865 and ≤885 kg / m 3 , even more preferably ≥865 and ≤880 kg / m 3 .

[0022] The ethylene-based polymer is preferably a copolymer of ethylene and one or more α-olefins selected from the following: 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene, particularly preferably 1-octene. 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% of polymer structural parts derived from 1-butene, 1-hexene, 4-methyl-1-pentene, or 1-octene, preferably derived from 1-octene, based on the total weight of the ethylene-based polymer.

[0023] As determined according to ASTM D1238 (2013) at 190 °C and a load of 2.16 kg, the melt mass flow rate of the ethylene-based polymer, for example, is ≥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.

[0024] The crosslinking agent can be selected, for example, from 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 3-di-tert-butyl peroxide, tert-butylcumyl peroxide, 2,5-dimethyl-2,5-bis(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.

[0025] The coupling agent can, 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 containing 1-5 carbon atoms; more preferably the coupling agent further contains a (meth)acrylate structural part.

[0026] 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.

[0027] The auxiliary agent may be, for example, a compound according to formula I:

[0028]

[0029] wherein:

[0030] · R1 is a trivalent structural moiety that is bonded to each R2 structural moiety via a heteroatom, preferably N or O; and

[0031] · 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 straight-chain structural moiety;

[0032] Preferably, each R2 is the same.

[0033] 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.

[0034] Preferably, the compound of formula I is selected from:

[0035]

[0036] 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.

[0037] Particularly preferably, the auxiliary agent is selected from triallyl cyanurate, triallyl phosphate, triallyl isocyanurate, and 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane.

[0038] The polymer composition according to the present invention can be prepared, for example, by a method comprising the following steps:

[0039] ● Providing a component group containing the following components to a mixing device such as a melt extruder:

[0040] ○ An ethylene-based polymer;

[0041] ○ A crosslinking agent of ≥ 0.1 wt% and ≤ 5.0 wt%, preferably ≥ 0.1 wt% and ≤ 1.0 wt%;

[0042] ○ A coupling agent of ≥ 0.05 wt% and ≤ 5.0 wt%, preferably ≥ 0.05 wt% and ≤ 0.5 wt%, preferably a silane coupling agent; and

[0043] ○ An auxiliary agent 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;

[0044] and

[0045] ● Mix the component group at a melting temperature of ≤ 100 °C, preferably ≥ 80 °C and ≤ 100 °C, for example, by extrusion, to form the polymer composition.

[0046] The present invention also relates to a film comprising the polymer composition according to the present invention. Such a film can be prepared, for example, by a method comprising the following steps:

[0047] ● Provide a component group containing the following components to a melt extruder:

[0048] ○ An ethylene-based polymer;

[0049] ○ A crosslinking agent of ≥ 0.1 wt% and ≤ 5.0 wt%, preferably ≥ 0.1 wt% and ≤ 1.0 wt%;

[0050] ○ A coupling agent of ≥ 0.05 wt% and ≤ 5.0 wt%, preferably ≥ 0.05 wt% and ≤ 0.5 wt%, preferably a silane coupling agent; and

[0051] ○ An auxiliary agent 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;

[0052] ● Extrude the component group at a melting temperature of ≤ 100 °C, preferably ≥ 80 °C and ≤ 100 °C, to form an extrudate;

[0053] and

[0054] ● Cast the extrudate at a temperature of ≤ 100 °C to form the film.

[0055] In another embodiment, the present invention also relates to an encapsulated solar cell module, which comprises a solar cell located between a first and a second sealing layer, wherein each of the first and second sealing layers comprises or consists of a film according to the present invention, and wherein the solar cell is arranged such that the first and second sealing layers are joined to completely encapsulate the solar cell.

[0056] Such an encapsulated solar cell module can be subjected to conditions sufficient to cure the first and second sealing layers, thereby obtaining a cured solar cell module. A method of manufacturing such a cured solar cell module can, for example, comprise the following steps:

[0057] a) providing a first and a second sealing layer, each of which comprises or consists of a film according to the present invention, and a solar cell;

[0058] 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 and second sealing layers; and

[0059] c) curing the encapsulated solar cell module under conditions sufficient to cure the first and second sealing layers.

[0060] Such conditions sufficient to cure the first and second sealing layers are preferably a temperature of 100 °C - 160 °C, preferably 120 °C - 150 °C, and a duration of ≥ 5 and ≤ 30 minutes, preferably ≥ 10 and ≤ 20 minutes.

[0061] In one embodiment, the present invention also relates to a photovoltaic module, which comprises:

[0062] a) a front protective member;

[0063] b) a rear protective member; and

[0064] 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.

[0065] The front protective member can 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 can be formed by a frame structure for the photovoltaic module.

[0066] Furthermore, the present invention also relates to the use of a polymer composition according to the present invention or a film according to the present invention for reducing the curing time of a solar cell module during the production of a photovoltaic module.

[0067] Figure 1 and 2Examples of cross-sections of photovoltaic modules are provided, which may include the polymer composition according to the present invention in its encapsulant material layer, where (1) represents the solar cell layer, each (2) is an encapsulant material layer, (3) is a front protective member, and (4) is a rear protective member. In Figure 3 a exploded view of such a photovoltaic module is provided, where each of the reference numerals (1)-(4) corresponds to Figure 1 and Figure 2 is the same.

[0068] The present invention will now be illustrated by the following non-limiting examples.

[0069] Material

[0070] In an embodiment according to the present invention, the materials listed in Table 1 below are used to prepare the polymer composition.

[0071] Table 1: Materials

[0072] 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

[0073] 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.

[0074] Table 2: Properties and characteristics of ethylene-based polymers

[0075] 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

[0076] Wherein:

[0077] ● The density is determined according to ASTM D792 (2008) and is expressed in kg / m 3 ;

[0078] ● MFR2 is the melt mass flow rate, determined according to ASTM D1238 (2013) at 190 °C and a load of 2.16 kg, and is expressed in g / 10 min;

[0079] ● The C8 content is the wt% of polymer units derived from 1-octene in the ethylene-based polymer, which is determined by 13 13C nuclear magnetic resonance on a Bruker Avance 500 spectrometer equipped with a low-temperature cooling probe operating at 125 °C, whereby the sample is dissolved in C2D2Cl4 containing DBPC as a stabilizer at 130 °C;

[0080] ● T p,m is the peak melting temperature determined by differential scanning calorimetry (DSC) according to ASTM D3418 (2008) and is expressed in °C;

[0081] ● Tc is the crystallization temperature determined by differential scanning calorimetry (DSC) in accordance with ASTM D3418 (2008), expressed in °C;

[0082] ●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 each is expressed in kg / mol and determined in accordance with ASTM D6474 (2012);

[0083] ● The vinyl content and the vinylidene content are the amounts of each of vinyl unsaturation and vinylidene unsaturation, expressed as the number of unsaturations per 100,000 chain carbon atoms, and determined by 13 13C NMR on a Bruker Avance 500 spectrometer equipped with a cryogenic cooling probe operating at 125 °C, whereby the sample is dissolved in C2D2Cl4 containing DBPC as a stabilizer at 130 °C.

[0084] In PE1 - 3, Figure 4 the elution profiles obtained by HPLC analysis at 160 °C are shown. A PolymerChar 2D-LC instrument is used, which has a Polymer Labs PL ELS 1000 light scattering detector. The HPLC elution is carried out at 160 °C at a flow rate of 1 mL / min. A Thermofischer Hypercarb column with a particle size of 7 μm, a length of 100 mm, and an inner diameter of 4.6 mm is used. It can be observed from this figure that PE1 and PE2 have a unimodal chemical composition distribution, indicated by the single peak in the figure, while PE3 has a bimodal chemical composition distribution, indicated by the presence of two peaks in the figure.

[0085] Composition

[0086] Using the materials listed above, the following compositions are produced according to the following formulation: Mix the materials in a glass container, keep the mixture at room temperature for 12 hours, and then press each composition at 90 °C into a polymer sheet with a thickness of 2 - 3 mm.

[0087] Table 3: Compositions

[0088] 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

[0089] For each of Examples 1 - 4, a curing test was conducted to obtain information on the crosslinking behavior of the composition. The compression - molded sheet obtained by the above - mentioned method was cured at 145 °C for 30 minutes, and the curing performance was determined according to ASTM D6601 - 12. This resulted in the torque performance shown in Table 4 below:

[0090] Table 4: Torque Performance of Compression - Molded Samples

[0091]

[0092] In the table above, Examples 1 and 3, and 2 and 4 are particularly relevant when compared to each other because the properties that generally define these products are similar for these combinations; in Examples 1 and 3, ethylene - based polymers of PE1 and PE3 are used respectively, and in Examples 2 and 4, ethylene - based polymers of PE2 and PE4 are used. 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.

[0093] The torque measurement results for each of Examples 1 - 4 are shown in Figure 5 .

[0094] From the results in Table 4, it can be observed that at the beginning of curing, as reflected by the value at 5 minutes, the torque value of Composition 1 is 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 beginning of curing for the examples according to the present invention is longer than that of the comparative examples. This is beneficial for the manufacturing process of encapsulated solar cell modules because it allows a longer period of time to have the flexibility to apply the encapsulation material to the solar cells.

[0095] Furthermore, it can be observed that at a curing time of 10 minutes, the torque value of Example 1 exceeds that of its equivalent Example 3, and the torque value of Example 2 exceeds 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 significantly 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.

[0096] This can also be observed by measuring the gel content of the cured samples. Samples of the materials in 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. Their values are listed in Table 5 below.

[0097] Table 5: Gel content of the cured samples

[0098] Example 1 2 3 4 5 6 7 8 Gel content (%) 81 89 80 87 82 89 77 85

[0099] As can be observed from Table 5, for the example groups (1-4) using TBEC as the crosslinking agent and for the example groups (5-8) using TAEC as the crosslinking agent, the gel content values of the compositions according to the present invention exceed those of their corresponding comparative compositions.

Claims

1. A polymer composition, comprising: a) an ethylene-based copolymer; b) a crosslinking agent in an amount of ≥ 0.1 wt% and ≤ 5.0 wt%, preferably ≥ 0.1 wt% and ≤ 1.0 wt%; 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; 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 structural moiety, an isocyanurate structural moiety or a cyanurate structural moiety; wherein all wt% are based on the total weight of the polymer composition; and wherein when measured according to ASTM D6248-98(2012), the vinyl unsaturation content of the ethylene-based copolymer is ≥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 polymer composition according to claim 1, wherein when measured according to ASTM D6248-98(2012), the vinylidene unsaturation content of the ethylene-based polymer is ≥ 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 polymer composition according to any one of claims 1-2, wherein when measured according to ASTM D6248-98(2012), when expressed as the unsaturation / 10 5 carbon atoms, the vinyl unsaturation content of the ethylene-based polymer is greater than its vinylidene unsaturation content.

4. The polymer composition 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 wt% of the ethylene-based copolymer based on the total weight of the polymer composition; and / or ● the density of the ethylene-based polymer measured according to ASTM D792(2008) is ≥ 850 and ≤ 900 kg / m 3 , preferably ≥ 865 and ≤ 885 kg / m 3 .

5. The polymer composition 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 the following: 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene, preferably 1-octene; and / or ● The ethylene-based polymer contains ≥55.0 wt% and ≤80.0 wt%, preferably ≥60.0 and ≤70.0 wt%, of polymer structural parts derived from ethylene, and / or wherein the ethylene-based polymer contains ≥20.0 and ≤45.0 wt%, preferably ≥30.0 and ≤40.0 wt%, of polymer structural parts derived from 1-butene, 1-hexene, 4-methyl-1-pentene, or 1-octene, preferably 1-octene, based on the total weight of the ethylene-based polymer; and / or ● The melt mass flow rate of the ethylene-based polymer is ≥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, measured according to ASTM D1238 (2013) at 190 °C and a load of 2.16 kg.

6. The polymer composition 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-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-di(tert-butylperoxy)butane, 1,1-bis(tert-butylperoxy)cyclohexane, tert-amylperoxy-2-ethylhexyl carbonate, tert-butylperoxy-2-ethylhexyl carbonate, tert-butylperoxybenzoate, 1,6-di(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 polymer composition according to any one of claims 1-6, wherein the coupling agent contains a silane structural part and at least one alkoxy structural part, preferably wherein the alkoxy structural part contains 1-5 carbon atoms; preferably wherein the coupling agent contains three alkoxy structural parts, each of which contains 1-5 carbon atoms; more preferably wherein the coupling agent further contains a (meth)acrylate structural part.

8. The polymer composition 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 polymer composition 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 to 10 carbon atoms, more preferably each R2 is a straight-chain 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 polymer composition according to claim 9, wherein the compound of Formula I is selected from: where each R3 is a structural moiety containing 1-5 carbon atoms, preferably where each R3 is a methyl, ethyl, n-propyl, isopropyl, n-butyl, or tert-butyl structural moiety, more preferably where each R3 is the same.

11. The polymer composition 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 method for preparing the polymer composition according to any one of claims 1-11, comprising the following steps: ● Providing a component group containing the following components to a melt extruder: ○ The ethylene-based polymer; ○ The crosslinking agent in an amount of ≥0.1 wt% and ≤5.0 wt%, preferably ≥0.1 wt% and ≤1.0 wt%; ○ The 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 ○ The 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 structural moiety, an isocyanurate structural moiety, or a cyanurate structural moiety; and ● The polymer composition is formed by extruding the component group at a melting temperature of ≤ 100 °C, preferably ≥ 80 °C and ≤ 100 °C.

13. A film comprising the polymer composition according to any one of claims 1-11.

14. A method for preparing the film according to claim 13, comprising the following steps: ● Providing a component group containing the following components to a melt extruder: ○ The ethylene-based polymer; ○ The crosslinking agent in an amount of ≥ 0.1 wt% and ≤ 5.0 wt%, preferably ≥ 0.1 wt% and ≤ 1.0 wt%; ○ The 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 ○ The 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; ● Extruding the component group at a melting temperature of ≤ 100 °C, preferably ≥ 80 °C and ≤ 100 °C to form an extrudate; and ● Casting the extrudate at a temperature of ≤ 100 °C to form the film.

15. Use of the polymer composition according to any one of claims 1-11 or the film according to claim 13 for reducing the curing time of solar cell assemblies during the production of photovoltaic modules.

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