Encapsulating composition and encapsulating film comprising same and electronic component assembly

Abstract

The present invention discloses an encapsulation composition, an encapsulation film including the encapsulation composition, and an electronic device module. The encapsulation composition includes a polymer matrix, a tackifier and a free radical initiator. Based on 100 parts by weight of the polymer matrix, the polymer matrix includes 5 to 100 parts by weight of highly branched polyethylene (P1), 0 to 95 parts by weight of an ethylene-α-olefin copolymer, and 0 to 70 parts by weight of an ethylene-polar monomer copolymer. The highly branched polyethylene (P1) is an ethylene homopolymer having a branch structure and has a degree of branching of not less than 40 branches/1,000 carbon atoms. A density of the ethylene-α-olefin copolymer is not higher than 0.91 g/cm.sup.3. The encapsulation composition provided by the present invention has good volume resistivity, aging resistance, processability and low cost.

Claims

1. An encapsulation composition, comprising a polymer matrix, a tackifier and a free radical initiator, wherein based on 100 parts by weight of the polymer matrix, the polymer matrix comprises 5 to 100 parts by weight of highly branched polyethylene (P1) and 0 to 95 parts by weight of an ethylene-α-olefin copolymer, and the highly branched polyethylene (P1) is an ethylene homopolymer having a branch structure and has a degree of branching of not less than 60 branches/1,000 carbon atoms.

2. The encapsulation composition according to claim 1, wherein the highly branched polyethylene (P1) is synthetised by catalyzing ethylene homopolymerization by a late transition metal catalyst and has a weight average molecular weight of 100,000 to 220,000.

3. The encapsulation composition according to claim 1, wherein an α-olefin in the ethylene-α-olefin copolymer has 3 to 30 carbon atoms and is selected from at least one of propylene, 1-butylene, 1-pentene, 3-methyl-1-butylene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-octylene, 1-decene, 1-dodecene, 1-tetradecene, 1-cetene, 1-octadecene, 1-eicosene, 1-docosene, 1-tetracosene, 1-cerotene, 1-octacosene or 1-triacontene, and a density of the ethylene-α-olefin copolymer is not higher than 0.91 g/cm.sup.3.

4. The encapsulation composition according to claim 1, wherein a melting point of the P1 and the ethylene-α-olefin copolymer is not higher than 90° C.

5. The encapsulation composition according to claim 1, wherein based on 100 parts by weight of the polymer matrix, an amount of the tackifier contained in the encapsulation composition is not less than 0.1 part by weight.

6. The encapsulation composition according to claim 1, wherein the tackifier is a polar monomer comprising at least one olefinic degree of unsaturation and one polar group, and the polar group comprises at least one of a carbonyl group, a carboxylic ester group, a carboxylic anhydride group, a siloxane group, a titanyl alkyl group or an epoxidized group.

7. The encapsulation composition according to claim 1, wherein the tackifier is a silane coupling agent and is selected from at least one of vinyl trimethoxysilane, vinyl triethoxysilane, vinyltri(methoxyethoxy)silane, vinyltriacetoxysilane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane or γ-acryloxypropyltrimethoxysilane.

8. The encapsulation composition according to claim 1, wherein based on 100 parts by weight of the polymer matrix, an amount of the free radical initiator contained in the encapsulation composition is not less than 0.1 part by weight.

9. The encapsulation composition according to claim 8, wherein the free radical initiator comprises at least one of a peroxide, an azo-initiator or a photo-initiator, and the peroxide is selected from at least one of di-tert-butyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, 1,1-di(tert-butylperoxide)-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)-hexyne-3, 1,4-bis-tert-butylperoxycumene, tert-butyl peroxybenzoate, tert-butylperoxy-2-ethylhexyl carbonate, benzoyl peroxide, tert-butyl peroxyneodecanoate, tert-butyl peroxyacetate, tert-butyl percaprylate or methyl ethyl ketone peroxide.

10. The encapsulation composition according to claim 1, wherein the encapsulation composition also comprises at least one of a free radical activator, an ultraviolet absorbent, a light stabilizer, an antioxidant, a glass fiber, a plasticizer, a nucleator, a chain extender, a flame retardant, an inorganic filler, a scorch retarder, a heat conduction filler, a metal ion trapping agent, a colorant, a brightener, a bonding additive or an anti-reflection modifier.

11. The encapsulation composition according to claim 1, wherein based on 100 parts by weight of the polymer matrix, the encapsulation composition further comprises: 0.05 to 10 parts of a free radical activator, 0 to 2 parts by weight of an ultraviolet absorbent, 0 to 5 parts by weight of an antioxidant, 0 to 5 parts by weight of a light stabilizer, and 0 to 2 parts by weight of a scorch retarder, wherein the ultraviolet absorbent is selected from at least one of a benzophenone compound, a benzotriazole compound or a salicylate compound, and the light stabilizer is selected from at least one of a hindered amine compound or a piperidine compound.

12. The encapsulation composition according to claim 1, wherein the polymer matrix further comprises a polyolefin polymer grafted with an unsaturated organic compound, the unsaturated organic compound is a polar monomer comprising at least one olefinic degree of unsaturation and one polar group, and the polar group comprises at least one of a carbonyl group, a carboxylic ester group, a carboxylic anhydride group, a siloxane group, a titanyl alkyl group or an epoxidized group.

13. The encapsulation composition according to claim 12, wherein the unsaturated organic compound is a vinyl silane coupling agent or maleic anhydride, and the polyolefin polymer grafted with the unsaturated organic compound is selected from at least one of the P1 or the ethylene-α-olefin copolymer.

14. An encapsulation material, comprising the encapsulation composition according to claim 13 and having a sheet form or a film form.

15. An electronic device module, comprising an electronic device and an encapsulation material in intimate contact with a surface of the electronic device, wherein the encapsulation material comprises the encapsulation composition according to claim 13.

16. The electronic device module according to claim 15, wherein the electronic device is a solar cell.

17. The electronic device module according to claim 15, wherein the electronic device module further comprises at least one glass cover sheet.

Description

DETAILED DESCRIPTION

(1) The following embodiments are given to further illustrate the present invention, but are not intended to limit the scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art to the present invention according to the content of the present invention still fall within the protection scope of the present invention.

(2) A first embodiment of the present invention provides an encapsulation composition which includes a polymer matrix, a tackifier and a free radical initiator. Based on 100 parts by weight of the polymer matrix, the polymer matrix includes 5 to 100 parts by weight of highly branched polyethylene (P1) and 0 to 95 parts by weight of an ethylene-α-olefin copolymer. The highly branched polyethylene (P1) is an ethylene homopolymer having a branch structure and has a degree of branching of not less than 40 branches/1,000 carbon atoms. A density of the ethylene-α-olefin copolymer is not higher than 0.91 g/cm.sup.3.

(3) A second embodiment of the present invention provides an encapsulation composition which includes a polymer matrix, a free radical initiator and a tackifier. Every 100 parts by weight of the polymer matrix includes 5 to 100 parts by weight of highly branched polyethylene (P1), 0 to 30 parts by weight of crystalline polyethylene and polypropylene, 0 to 95 parts by weight of an ethylene-α-olefin copolymer, and 0 to 70 parts by weight of an ethylene-polar monomer copolymer. Based on 100 parts by weight of the polymer matrix, the amount of the free radical initiator is 0.1 to 5 parts by weight, and the amount of the tackifier is 0.1 to 5 parts by weight.

(4) A third embodiment of the present invention provides an encapsulation composition which includes a polymer matrix, a tackifier and a free radical initiator. The polymer matrix is highly branched polyethylene.

(5) The used highly branched polyethylene is synthetised by catalyzing ethylene homopolymerization through coordination polymerization by adopting a late transition metal catalyst. Preferably, the transition metal catalyst may be one of (α-diimine)nickel and (α-diimine)palladium catalysts. In terms of cost, the (α-diimine)nickel catalyst is preferred. The structure and the synthesis method of the used (α-diimine)nickel catalyst and the method for preparing branched polyethylene by the (α-diimine)nickel catalyst are disclosed in the prior art, the following literatures can be adopt, but are not limited to: CN102827312A, CN101812145A, CN101531725A, CN104926962A, U.S. Pat. Nos. 6,103,658, and 6,660,677. A cocatalyst can be selected from one or more of aluminum diethyl monochloride, aluminum ethyl dichloride, ethyl aluminum sesquichloride, methylaluminoxane and modified methylaluminoxane.

(6) The basic parameters, such as the degree of branching, the molecular weight and the melting point of the used highly branched polyethylene can be adjusted by adjusting the structure of the catalyst and polymerization conditions. The highly branched polyethylene adopted by the present invention has a degree of branching of not less than 40 branches/1,000 carbon atoms, further preferably 45 to 130 branches/1,000 carbon atoms, further preferably 60 to 116 branches/1,000 carbon atoms, and further preferably 62 to 83 branches/1,000 carbon atoms, has a weight average molecular weight of 50,000 to 500,000, further preferably 200,000 to 450,000, or 100,000 to 200,000, 102,000 to 213,000, or 114,000 to 175,000, and has a melting point of not higher than 125° C., further preferably −44 to 101° C., further preferably not higher than 90° C., further preferably −30 to 80° C., further preferably 40 to 80° C., or 55 to 65° C., or 70 to 80° C. A melt index measured at 190° C. and under a load of 2.16 kg may be 0.1 to 50 g/10 min, preferably 5 to 25 g/10 min, further preferably 10 to 20 g/10 min, or 5 to 10 g/10 min, or 10 to 15 g/10 min, or 15 to 20 g/10 min. In every 100 parts by weight of the polymer matrix, the amount of the highly branched polyethylene is 70 to 100 parts by weight preferably.

(7) The used ethylene-α-olefin copolymer is an ethylene-octylene copolymer (POE).

(8) The used ethylene-polar monomer copolymer is an ethylene-vinyl acetate copolymer (EVA).

(9) The used free radical initiator is a peroxide crosslinking agent, such as tert-butylperoxy-2-ethylhexyl carbonate.

(10) The used tackifier is a silane coupling agent, such as vinyl trimethoxysilane, vinyl triethoxysilane and vinyltri(methoxyethoxy)silane.

(11) In an embodiment, auxiliary components can be added to the encapsulation composition to obtain or improve various properties in a targeted manner.

(12) The auxiliary components include a free radical activator, an ultraviolet absorbent, a light stabilizer, an antioxidant, a glass fiber, a plasticizer, a nucleator, a chain extender, a flame retardant, an inorganic filler, a scorch retarder, a heat conduction filler, a metal ion trapping agent, a colorant, a brightener, an anti-reflection modifier, a bonding additive and the like, and the auxiliary components are used according to conventional amounts.

(13) A preparation method of an encapsulation film including the aforementioned encapsulation composition includes the following steps:

(14) (1) firstly, performing blending, grafting and extruding on a part of or all of a polymer matrix, all of a tackifier and a free radical initiator with a weight of 3% to 20% of that of the tackifier through an extruder to obtain a graft-modified polymer matrix A, wherein a temperature of the extruder is controlled at 50 to 210° C.; and

(15) (2) uniformly mixing the polymer matrix A with other components and then putting a mixture into the extruder for blending and extruding, casting an extrudate to form a film, cooling and pulling the film for shaping, and finally, performing a coiling process to obtain the encapsulation film, wherein the temperature of the extruder is controlled at 80 to 210° C.

(16) In order to more clearly describe the embodiments of the present invention, the materials involved in the embodiments of the present invention are defined as below.

(17) The highly branched polyethylene used in the embodiments has a degree of branching of 46 to 130 branches/1,000 carbon atoms, a weight average molecular weight of 66,000 to 471,000, and a melting point of −44 to 101° C., wherein the degree of branching is measured by nuclear magnetic resonance, the molecular weight and the molecular weight distribution are measured by PL-GPC220, and the melting point is measured by differential scanning calorimetry.

(18) The details are as follows:

(19) TABLE-US-00001 Number of highly Weight average Molecular branched Degree of molecular weight Melting polyethylene branching weight/10,000 distribution point/° C. PER-1 130 6.6 2.2 −44 PER-2 116 20.1 2.1 −30 PER-3 105 26.8 2.1 −17 PER-4 102 27.9 2.1 2 PER-5 98 28.3 1.8 16 PER-6 92 32.1 1.9 38 PER-7 82 35.6 1.7 52 PER-8 72 28.3 1.9 60 PER-9 70 39.6 2.0 71 PER-10 63 42.8 2.2 76 PER-11 52 31 1.8 85 PER-12 46 47.1 2.3 101 PER-13 62 21.3 2.1 84 PER-14 67 17.5 1.9 66 PER-15 70 13.6 2.0 63 PER-16 72 12.2 1.9 57 PER-17 75 11.4 2.1 56 PER-18 83 10.2 2.0 54

(20) Property Test Method:

(21) (1) Crosslinking degree and peel strength: the crosslinking degree and the peel strength were measured according to GB/T 29848-2013 standards.

(22) (2) Light transmittance: samples were tested by a spectrophotometer method according to GB/T 2410-2008. A wavelength range of the spectrophotometer was set to be 290 to 1,100 nm. Averages of the light transmittance in waveband ranges of 290 to 380 nm and 380 to 1,100 nm were respectively calculated. At least three samples were tested in each group, and the test results were averaged. The light transmittance described in the embodiments of the present invention was directed to a test result in the waveband range of 380 to 1,100 nm.

(23) (3) Volume resistivity: firstly, the samples were put in a laboratory at 23° C.±2° C. and 50%±5% RH for at least 48 h, then, the volume resistivity of the samples was tested under the conditions of 1,000 V±2 V and electrochemical time of 60 min according to requirements specified in GB/T 1410-2006, three samples were tested, and the results were averaged.

(24) (4) Humidity, heat and aging resistance and yellowing index: firstly, all samples were put into a high-temperature and high-humidity aging test box, and test conditions were set as follows: the temperature was 85° C.±2° C., and the relative humidity was 85%±5%; the test time was 1,000 h, the samples were taken out after the test and were restored for 2 to 4 h in an open environment with a relative humidity of less than 75% at 23° C.±5° C., then, an appearance inspection was performed, and no appearance defects were required; and finally, the yellowing indexes of laminate samples before and after the test were respectively measured according to ASTM E313, no less than three points were measured for each sample, the yellowing index of the sample was the average of the measured points, and the difference of change in yellowing indexes before and after aging was recorded.

(25) (5) PID resistance test: the test was performed at 85° C. and 85 RH % with a voltage of −1,000V.

Embodiments 1 to 8 and Comparative Example 1

(26) Encapsulation film and crosslinking speed test thereof:

(27) Encapsulation compositions of which the polymer matrixes were respectively DOW ENGAGE 8137 and PER-15 were compared, under the following formula, the optimum vulcanization time Tc90 of the test was performed according to the national standard GB/T16584-1996, the test was performed in a rotorless vulcanizer, the test temperature was 150° C., and the test duration was 30 min. The formula includes 100 parts by weight of polymer matrix, 1 part by weight of vinyl trimethoxysilane, 1 part by weight of tert-butylperoxy-2-ethylhexyl carbonate, 0.5 part by weight of triallyl isocyanurate, 0.25 part by weight of tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropanoate pentaerythritol ester, 0.15 part by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, and 0.15 part by weight of 2-hydroxy-4-n-octyloxybenzophenone. A polymer matrix and liquid components were soaked and mixed, a mixture and other components were blended and extruded in an extruder, the extrusion temperature was controlled at 90±1° C., the retention time of the mixture in the extruder was 4 min, an extrudate was cast to form a film, the film was cooled, split and coiled to obtain a transparent encapsulation film having a thickness of 0.5 mm, samples were cut and folded into about 5 g of samples to be tested, and then, the test was performed, wherein specific proportions of DOW ENGAGE 8137 and PER-15 in polymer matrixes and the corresponding Tc90 were shown in table 1:

(28) TABLE-US-00002 TABLE 1 Embodi- Embodi- Embodi- Embodi- Embodi- Embodi- Embodi- Embodi- Comparative Polymer matrix ment 1 ment 2 ment 3 ment 4 ment 5 ment 6 ment 7 ment 8 example 1 PER-15content 100 95 90 70 50 30 10 5 0 DOW ENGAGE 0 5 10 30 50 70 90 95 100 8137 content Tc90/s 429 447 471 542 633 721 782 805 820

(29) By comparing Embodiments 1 to 8 with Comparative Example 1, it can be clearly found that the crosslinking speed of the highly branched polyethylene with an appropriate degree of branching was significantly higher than that of a polyolefin copolymer commonly used in the prior art. When the polymer matrix of an encapsulation composition or an encapsulation material partially or completely adopts the highly branched polyethylene, under the same processing conditions, the crosslinking speed can be effectively increased to shorten the crosslinking and curing time required for modules during processing and shaping, so that on the one hand, the energy consumption can be effectively reduced and the production capacity can be increased, and on the other hand, electronic devices, such as solar cell sheets, can be protected to shorten the retention time thereof at high temperature and high pressure.

Embodiments 9 to 16 and Comparative Examples 1 and 2

(30) The formula components of Embodiments 9 to 16 and Comparative Examples 2 and 3 were shown in table 2: (based on every 100 parts by weight of the polymer matrix, parts by weight of all components were listed)

(31) TABLE-US-00003 TABLE 2 Compar- Compar- Embodi- Embodi- Embodi- Embodi- Embodi- Embodi- Embodi- Embodi- ative ative Component ment 9 ment 10 ment 11 ment 12 ment 13 ment 14 ment 15 ment 16 Example 1 Example 2 Number of PER PER-6 PER-15 PER-7 PER-7 PER-8 PER-2/ PER-6 PER-6 PER-10 PER amount 100 100 100 100 100 40/60 60 30 EVA(VA: 33%, 70 100 MI: 30) POE(octylene: 40%, 40 100 MI: 30) Silane coupling 1 1 2 5 1 1 1 0.1 1 0.1 agent: vinyl trimethoxysilane Peroxide: 1 1 2 5 1 1 1 1 1 1 tert-butylperoxy-2- ethylhexyl carbonate Auxiliary 0.5 0.5 0.5 2 0.5 0.5 0.5 0.5 0.5 0.5 crosslinking agent: triallyl isocyanurate Antioxidant: 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 tetrakis(3,5- di-tert-butyl-4- hydroxy)phenylpropanoate pentaerythritol ester Antioxidant: 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 bis(2,4-dicumylphenyl)penta- erythritol diphosphite Light stabilizer: 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 bis(2,2,6,6-tetramethyl- 4-piperidinyl)sebacate Ultraviolet absorbent: 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 2-(2′-hydroxy-3′,5′-di- tert-butylphenyl)- benzotriazole

(32) An encapsulation composition according to each of Embodiments 9 to 16 was mixed through an internal mixer and then calendered or extruded to form a film having a thickness of 0.5 mm, a flat glass and a TFT back board were respectively attached to two surfaces of the film, and then, the obtained laminates were laminated in a vacuum laminator.

(33) The property test data of each test sample was shown in table 3:

(34) TABLE-US-00004 TABLE 3 Embodi- Embodi- Embodi- Embodi- Embodi- Embodi- Embodi- Embodi- Comparative Comparative Property test ment 9 ment 10 ment 11 ment 12 ment 13 ment 14 ment 15 ment 16 Example 2 Example 3 Crosslinking 79 79 84 90 76 82 76 81 73 84 degree/% Light 92 91 92 92 88 90 90 91 89 91 transmittance/% Peel 134 121 138 145 118 129 131 112 124 128 strength with glass/(N/cm) Volume 18.5 25.2 18.6 14.1 22.7 20.2 13.3 4.2 8.2 2.8 resistivity/ (10{circumflex over ( )}15 Ω .Math. cm) After humidity, heat and aging resistance Peel 114 105 121 109 107 111 113 80 110 75 strength with glass/(N/cm) Yellowing 1.1 0.9 0.9 1 0.8 1 1 2.7 1 3.4 index (ΔΥI)

(35) By comparing Embodiment 8, Embodiment 15 and Comparative Example 2, it can be found that by adopting the highly branched polyethylene to partially or completely replace the POE in the prior art, an encapsulation film can be endowed with better crosslinking degree, light transmittance, volume resistivity and adhesion with glass.

(36) By comparing Embodiments 9 to 14 with Comparative Example 3, it can be found that an encapsulation film using the highly branched polyethylene as a polymer matrix has excellent transparency, which ensures that a solar cell using the encapsulation film has good power generation efficiency. Secondly, the encapsulation film using the highly branched polyethylene as the polymer matrix has good peel strength with glass, and after humidity, heat and aging resistance, the retention rate of the peel strength between the encapsulation film and the glass was much higher than the retention rate of the peel strength between an EVA encapsulation film in the Comparative Example and the glass, and the yellowing index of the encapsulation film was also much lower than the yellowing index of the EVA encapsulation film in the Comparative Example, thereby indicating that the encapsulation film using the highly branched polyethylene as the polymer matrix in the present invention has excellent adhesion and humidity, heat and aging resistance and can be better adapted to outdoor environments. The novel encapsulation film provided by the present invention adopts the highly branched polyethylene of which the molecular chain is of a completely saturated hydrocarbon structure, so that the novel encapsulation film has very high volume resistivity and has significant advantages relative to the EVA encapsulation film in terms of electrical insulation property.

(37) By comparing Embodiment 16 with Comparative Example 3, it can be found that by adopting the highly branched polyethylene to partially replace the EVA in the prior art, the humidity, heat and aging resistance of the EVA encapsulation film can be significantly improved, the yellowing index was reduced, the electrical insulation property was improved, the property defects of the existing EVA encapsulation film were well improved, and although the adhesion strength between the encapsulation film and the glass was reduced, it still meets the industry standard higher than 60 N/cm.

Embodiment 17

(38) Single-Glass Solar Cell Module:

(39) An encapsulation film having a thickness of 0.5 mm was prepared from an encapsulation composition including the following substances: 100 parts by weight of PER-13 (MI at 190° C. and under a load of 2.16 kg was 1 g/10 min), 1 part by weight of vinyl trimethoxysilane, 1 part by weight of tert-butylperoxy-2-ethylhexyl carbonate, 0.5 part by weight of triallyl isocyanurate, 0.05 part by weight of 4-hydroxy-TEMPO, 0.25 part by weight of tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropanoate pentaerythritol ester, 0.15 part by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, and 0.15 part by weight of 2-hydroxy-4-n-octyloxybenzophenone. A polymer matrix and liquid components were soaked and mixed, a mixture and other components were blended and extruded in an extruder, the extrusion temperature was controlled at 90±1° C., the retention time of the mixture in the extruder was 4 min, an extrudate was cast to form a film, and the film was cooled, split and coiled to obtain an encapsulation film having a thickness of 0.5 mm. A solar cell module was prepared by a laminating method at 145° C., wherein the encapsulation film was located between a glass cover plate and a solar cell and also located between a TPT back board and the solar cell. PID resistance test: after 192 h of testing, the output power attenuation degree was 0.82%.

Embodiment 18

(40) Single-Glass Solar Cell Module:

(41) An encapsulation film having a thickness of 0.5 mm was prepared from an encapsulation composition including the following substances: 90 parts by weight of PER-14 (MI at 190° C. and under a load of 2.16 kg was 5 g/10 min), 10 parts by weight of a maleic anhydride modified ethylene-1-octylene copolymer (grafting content of MAH is 1 wt %, MI:1.5 g/10 min), 1 part by weight of vinyl trimethoxysilane, 1 part by weight of tert-butylperoxy-2-ethylhexyl carbonate, 0.5 part by weight of triallyl isocyanurate, 0.05 part by weight of 4-hydroxy-TEMPO, 0.25 part by weight of tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropanoate pentaerythritol ester, 0.15 part by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, and 0.15 part by weight of 2-hydroxy-4-n-octyloxybenzophenone. A polymer matrix and liquid components were soaked and mixed, a mixture and other components were blended and extruded in an extruder, the extrusion temperature was controlled at 90±1° C., the retention time of the mixture in the extruder was 4 min, an extrudate was cast to form a film, and the film was cooled, split and coiled to obtain an encapsulation film having a thickness of 0.5 mm. A solar cell module was prepared by a laminating method at 145° C., wherein the encapsulation film was located between a glass cover plate and a solar cell and also located between a TPT back board and the solar cell. PID resistance test: after 192 h of testing, the output power attenuation degree was 0.88%.

Embodiment 19

(42) Single-Glass Solar Cell Module:

(43) An encapsulation film having a thickness of 0.5 mm was prepared from an encapsulation composition including the following substances: 70 parts by weight of PER-15 (MI at 190° C. and under a load of 2.16 kg was 13 g/10 min), 30 parts by weight of Dow POE8137, 1 part by weight of vinyl trimethoxysilane, 1 part by weight of tert-butylperoxy-2-ethylhexyl carbonate, 0.5 part by weight of triallyl isocyanurate, 0.25 part by weight of tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropanoate pentaerythritol ester, 0.15 part by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, and 0.15 part by weight of 2-hydroxy-4-n-octyloxybenzophenone. A polymer matrix and liquid components were soaked and mixed, a mixture and other components were blended and extruded in an extruder, the extrusion temperature was controlled at 90±1° C., the retention time of the mixture in the extruder was 4 min, an extrudate was cast to form a film, and the film was cooled, split and coiled to obtain an encapsulation film having a thickness of 0.5 mm. A solar cell module was prepared by a laminating method at 145° C., wherein the encapsulation film was located between a glass cover plate and a solar cell and also located between a TPT back board and the solar cell. PID resistance test: after 192 h of testing, the output power attenuation degree was 0.81%.

Embodiment 20

(44) Single-Glass Solar Cell Module:

(45) An encapsulation film having a thickness of 0.5 mm was prepared from an encapsulation composition including the following substances: 100 parts by weight of PER-18 (MI at 190° C. and under a load of 2.16 kg was 30 g/10 min), 1 part by weight of vinyl trimethoxysilane, 1 part by weight of tert-butylperoxy-2-ethylhexyl carbonate, 0.5 part by weight of triallyl isocyanurate, 0.05 part by weight of 4-hydroxy-TEMPO, 0.25 part by weight of tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropanoate pentaerythritol ester, 0.15 part by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, and 0.15 part by weight of 2-hydroxy-4-n-octyloxybenzophenone. A processing method was as follows: all polymer matrixes, all silane coupling agents and peroxides of which the weight was 10% of the weight of the silane coupling agents were mixed uniformly, and then, a mixture was added to a double screw extruder for blending and extruding; the temperature of a feed end of the double screw extruder was 50° C., the temperature of a reactor injected with nitrogen gas was 210° C., the temperature of an outlet after reaction was 140° C., and a graft-modified polymer matrix A was obtained; the graft-modified polymer matrix A and other components were mixed uniformly, and then, the mixture was extruded into a film in cooperation with a T-shaped mold through the double screw extruder; nitrogen gas was injected into the extruder, and the extrusion temperature was controlled at 110° C.; the retention time of the mixture in the extruder was 4 min; and an extrudate was cast to form a film, and the film was cooled, split and coiled to obtain an encapsulation film having a thickness of 0.5 mm. A solar cell module was prepared by a laminating method at 145° C., wherein the encapsulation film was located between a glass cover plate and a solar cell and also located between a TPT back board and the solar cell. PID resistance test: after 192 h of testing, the output power attenuation degree was 0.83%.

Embodiment 21

(46) Double-Glass Solar Cell Module in which Two Layers of Films were Transparent Films:

(47) An encapsulation film having a thickness of 0.5 mm was prepared from an encapsulation composition including the following substances: 100 parts by weight of PER-16 (MI at 190° C. and under a load of 2.16 kg was 13 g/10 min), 1 part by weight of vinyl trimethoxysilane, 1 part by weight of tert-butylperoxy-2-ethylhexyl carbonate, 0.5 part by weight of triallyl isocyanurate, 0.05 part by weight of 4-hydroxy-TEMPO, 0.25 part by weight of tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropanoate pentaerythritol ester, 0.15 part by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, and 0.15 part by weight of 2-hydroxy-4-n-octyloxybenzophenone. A polymer matrix and liquid components were soaked and mixed, a mixture and other components were blended and extruded in an extruder, the extrusion temperature was controlled at 90±1° C., the retention time of the mixture in the extruder was 4 min, an extrudate was cast to form a film, and the film was cooled, split and coiled to obtain an encapsulation film having a thickness of 0.5 mm. A solar cell module was prepared by a laminating method at 145° C., wherein the solar cell was an N-type cell sheet, and the encapsulation film was located between a glass cover plate and the solar cell and also located between another glass cover plate and the solar cell. PID resistance test: after 192 h of testing, the output power attenuation degree was 0.63%.

Embodiment 22

(48) Double-Glass Solar Cell Module in which an Upper Layer was a Transparent Film and a Lower Layer was a White Film:

(49) An upper-layer encapsulation film having a thickness of 0.5 mm was prepared from an encapsulation composition including the following substances: 100 parts by weight of PER-16 (MI at 190° C. and under a load of 2.16 kg was 13 g/10 min), 1 part by weight of vinyl trimethoxysilane, 1 part by weight of tert-butylperoxy-2-ethylhexyl carbonate, 0.5 part by weight of triallyl isocyanurate, 0.05 part by weight of 4-hydroxy-TEMPO, 0.25 part by weight of tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropanoate pentaerythritol ester, 0.15 part by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, and 0.15 part by weight of 2-hydroxy-4-n-octyloxybenzophenone. A polymer matrix and liquid components were soaked and mixed, a mixture and other components were blended and extruded in an extruder, the extrusion temperature was controlled at 90±1° C., the retention time of the mixture in the extruder was 4 min, an extrudate was cast to form a film, and the film was cooled, split and coiled to obtain a transparent encapsulation film having a thickness of 0.5 mm.

(50) A lower-layer encapsulation film having a thickness of 0.5 mm was prepared from an encapsulation composition including the following substances: 100 parts by weight of PER-16 (MI at 190° C. and under a load of 2.16 kg was 13 g/10 min), 10 parts by weight of titanium dioxide powder, 1 part by weight of vinyl trimethoxysilane, 1 part by weight of tert-butylperoxy-2-ethylhexyl carbonate, 0.5 part by weight of triallyl isocyanurate, 0.05 part by weight of 4-hydroxy-TEMPO, 0.25 part by weight of tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropanoate pentaerythritol ester, 0.15 part by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, and 0.15 part by weight of 2-hydroxy-4-n-octyloxybenzophenone. A polymer matrix and liquid components were soaked and mixed, a mixture and other components were blended and extruded in an extruder, the extrusion temperature was controlled at 90±1° C., the retention time of the mixture in the extruder was 4 min, an extrudate was cast to form a film, and the film was cooled, split and coiled to obtain a transparent encapsulation film having a thickness of 0.5 mm.

(51) A solar cell module was prepared by a laminating method at 145° C., wherein the solar cell was an N-type cell sheet, the transparent encapsulation film was located between an upper-layer glass cover plate and the solar cell, and the white film was located between a lower-layer glass cover plate and the solar cell. PID resistance test: after 192 h of testing, the output power attenuation degree was 0.68%.

Embodiment 23

(52) Double-Glass Solar N-Type Double-Sided Cell Module in which a Cell was an N-Type Double-Sided Cell and Two Layers of Films were Transparent Films:

(53) An encapsulation film having a thickness of 0.5 mm was prepared from an encapsulation composition including the following substances: 100 parts by weight of PER-16 (MI at 190° C. and under a load of 2.16 kg was 13 g/10 min), 1 part by weight of vinyl trimethoxysilane, 1 part by weight of tert-butylperoxy-2-ethylhexyl carbonate, 0.5 part by weight of triallyl isocyanurate, 0.05 part by weight of 4-hydroxy-TEMPO, 0.25 part by weight of tetrakis(3,5-di-tert-butyl-4-hydroxy)phenylpropanoate pentaerythritol ester, 0.15 part by weight of bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, and 0.15 part by weight of 2-hydroxy-4-n-octyloxybenzophenone. A polymer matrix and liquid components were soaked and mixed, a mixture and other components were blended and extruded in an extruder, the extrusion temperature was controlled at 90±1° C., the retention time of the mixture in the extruder was 4 min, an extrudate was cast to form a film, and the film was cooled, split and coiled to obtain an encapsulation film having a thickness of 0.5 mm. A solar cell module was prepared by a laminating method at 145° C., wherein the solar cell was an N-type double-sided cell sheet, and the encapsulation film was located between a glass cover plate and a solar cell and also located between another glass cover plate and the solar cell. PID resistance test: after 192 h of testing, the output power attenuation degree was 1.52%.

(54) In general, under the condition that the content of the highly branched polyethylene is higher, the encapsulation film including the encapsulation composition of the present invention has excellent weather resistance, aging resistance, yellowing resistance and electrical insulation property and good optical properties and adhesion, and has obvious advantages compared with an existing EVA encapsulation film and an existing POE encapsulation film. Under the condition that the content of the highly branched polyethylene is lower, it is also expected to improve the property defects of the EVA encapsulation film and the POE encapsulation film. Theoretically, the production cost of the highly branched polyethylene is significantly lower than that of the POE, and the crosslinking speed of the highly branched polyethylene is higher than that of the POE, thereby reducing the time cost and increasing the production efficiency for photovoltaic module suppliers. Therefore, from the perspective of property and cost, the solution of the present invention has obvious advantages than the prior art.

(55) The above embodiments are merely preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any non-essential changes and replacements made by those skilled in the art on the basis of the present invention fall within the protection scope of the present invention.