# US 9,040,811 B2 · Solar-cell sealant and solar-cell module using same

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- Number: US 9,040,811 B2
- Document ID: US9040811B2
- Status: Granted
- Kind: B2
- Application number: 13/885,863
- Filed: 2011-11-17
- Published: 2013-09-12
- Granted: 2015-05-26
- Earliest claimed: 2010-11-17
- Assignees: Mitsui Chemicals Tohcello, Inc.
- Applicants: Shigenobu Ikenaga; Fumito Takeuchi; Keiji Watanabe; Tomoaki Ito
- Inventors: Shigenobu Ikenaga; Fumito Takeuchi; Keiji Watanabe; Tomoaki Ito
- Web page: https://patentgrep.com/patent/US9040811B2

## CPC

- H10F 19/804: {Materials of encapsulations}
- C08F 4/65908: {in combination with an ionising compound other than alumoxane, e.g. (C6F5)4B-X+}
- C08F 4/65912: {in combination with an organoaluminium compound}
- C08F 210/18: with non-conjugated dienes, e.g. EPT rubbers
- C09K 3/10: {Materials in mouldable or extrudable form} for sealing or packing joints or covers (filling pastes C09D5/34)
- H10F 77/50: Encapsulations or containers (for photovoltaic modules H10F19/80)
- C09K 2200/0642: Copolymers containing at least three different monomers
- Y02E 10/50: Photovoltaic [PV] energy
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A solar-cell sealant that has excellent properties such as transparency, flexibility, adhesiveness, heat resistance, appearance, cross-linking characteristics, electrical characteristics, and calenderability. A solar-cell sealant that contains an ethylene/α-olefin/unconjugated-polyene copolymer satisfying requirements (a1) through (a3). Requirement (a1) is that constituent units derived from ethylene constitute 80-90 mol %, constituent units derived from C3-20 α-olefin constitute 9.99-19.99 mol %, and constituent units derived from an unconjugated polyene constitute 0.01-5.0 mol % of said copolymer. Requirement (a2) is that the MFR of said copolymer, as measured in accordance with ASTM D1238 at 190° C. under a 2.16 kg load, be at least 2 g/10 min. and less than 10 g/10 min. Requirement (a3) is that the Shore A hardness of said copolymer, as measured in accordance with ASTM D2240, be 60 to 85.

## Claims

### Claim 1

A solar cell encapsulant comprising an ethylene/α-olefin/non-conjugated polyene copolymer which satisfies the following requirements a1) to a3):
a1) a structural unit derived from ethylene is present in an amount of 80-90mol %, a structural unit derived from a C3-20 α-olefin is present in an amount of 9.99-19.99mol %, and a structural unit derived from a non-conjugated polyene is present in an amount of 0.01-5.0 mol %;
a2) a melt flow rate measured in accordance with ASTM D1238 at 190° C. under a load of 2.16 kg is 2 g/10 min to 10 g/10 min; and
a3) a Shore A hardness measured in accordance with ASTM D2240 is 60-85.

### Claim 2 (depends on 1)

The solar cell encapsulant according to claim 1, wherein the solar cell encapsulant satisfies the following requirement a4):
a4) a volume resistivity measured at 100° C. and applied voltage of 500V in accordance with JIS K6911 is 1.0×1013-1.0×1018 Ω·cm.

### Claim 3 (depends on 1)

The solar cell encapsulant according to claim 1, further comprising 0.1-5.0 parts by weight of a silane coupling agent and 0.1-2.5 parts by weight of a crosslinking agent per 100 parts by weight of the ethylene/α-olefin/non-conjugated polyene copolymer.

### Claim 4 (depends on 3)

The solar cell encapsulant according to claim 3, wherein the crosslinking agent is an organic peroxide having a 1 minute half-life temperature of 100-170° C.

### Claim 5 (depends on 3)

The solar cell encapsulant according to claim 3, further comprising 0.05-5 parts by weight of at least one agent selected from the group consisting of a UV absorber, a thermal stabilizer, and a hindered amine light stabilizer, per 100 parts by weight of the ethylene/α-olefin/non-conjugated polyene copolymer.

### Claim 6 (depends on 3)

The solar cell encapsulant according to claim 3, further comprising 0.05-5 parts by weight of a crosslinking aid per 100 parts by weight of the ethylene/α-olefin/non-conjugated polyene copolymer.

### Claim 7 (depends on 1)

The solar cell encapsulant according to claim 1, wherein the ethylene/α-olefin/non-conjugated polyene copolymer further satisfies the following requirement a5):
a5) a B value calculated from a 13C-NMR spectrum and the following formula (1) is 0.9-1.3:
B=(c+d)/(2×a×(e+f)) (1)
where a denotes a ratio of the structural unit derived from ethylene (molar fraction of ethylene) in the ethylene/α-olefin/non-conjugated polyene copolymer;
c denotes a ratio of a structural unit of ethylene/α-olefin chain (molar fraction of ethylene/α-olefin dyad sequence);
d denotes a ratio of a structural unit of ethylene/non-conjugated polyene chain (molar fraction of ethylene/non-conjugated polyene dyad sequence);
e denotes a ratio of the structural unit derived from the α-olefin (molar fraction of α-olefin); and
f denotes a ratio of the structural unit derived from the non-conjugated polyene (molar fraction of non-conjugated polyene).

### Claim 8 (depends on 1)

The solar cell encapsulant according to claim 1, wherein the ethylene/α-olefin/non-conjugated polyene copolymer further satisfies the following requirement a6):
a6) a maximum value Pmax and a minimum value Pmin of an ethylene distribution parameter P measured by GPC-offline-FTIR satisfy the following formula (2):
Pmax/Pmin≦1.4 (2)

### Claim 9 (depends on 1)

The solar cell encapsulant according to claim 1, wherein the ethylene/α-olefin/non-conjugated polyene copolymer further satisfies the following requirement a7):
a7) an activation energy (Ea) of fluidization is 28-45 kJ/mol.

### Claim 10 (depends on 1)

The solar cell encapsulant according to claim 1, wherein the ethylene/α-olefin/non-conjugated polyene copolymer further satisfies the following requirement a8):
a8) a molecular weight distribution Mw/Mn based on gel permeation chromatography (GPC) is 1.2-3.5.

### Claim 11 (depends on 1)

The solar cell encapsulant according to claim 1, wherein the ethylene/α-olefin/non-conjugated polyene copolymer further satisfies the following requirement a9):
a9) a chlorine ion content in an eluate from solid-phase-extraction as detected by ion chromatography is 2 ppm or less.

### Claim 12 (depends on 1)

The solar cell encapsulant according to claim 1, wherein the ethylene/α-olefin/non-conjugated polyene copolymer further satisfies the following requirement a10):
a10) an amount of the ethylene/α-olefin/non-conjugated polyene copolymer extracted into methyl acetate is 5.0 wt % or less.

### Claim 13 (depends on 1)

The solar cell encapsulant according to claim 1, wherein the solar cell encapsulant is in sheet form.

### Claim 14 (depends on 1)

A solar cell module comprising:
a transparent front protection member;
a back protection member;
a solar cell sandwiched between the front protection member and the back protection member; and
an encapsulant that encapsulates the solar cell between the transparent front protection member and back protection member,
wherein the encapsulant is a cured material of the solar cell encapsulant according to claim 1.

### Claim 15 (depends on 1)

The solar cell encapsulant according to claim 1, wherein the solar cell encapsulant is prepared by calendaring a melt-kneaded material into sheet, the melt-kneaded material comprising the ethylene/α-olefin/non-conjugated polyene copolymer and an additive.