# US 10,872,990 B2 · Electronic devices comprising two encapsulant films

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- Number: US 10,872,990 B2
- Document ID: US10872990B2
- Status: Granted
- Kind: B2
- Application number: 16/222,112
- Filed: 2018-12-17
- Published: 2019-05-09
- Granted: 2020-12-22
- Earliest claimed: 2013-04-22
- Assignees: Dow Global Technologies LLC
- Applicants: Dow Global Technologies LLC
- Inventors: Kumar Nanjundiah; John A. Naumovitz; Michael D. White
- Web page: https://patentgrep.com/patent/US10872990B2

## CPC

- H10F 19/804: {Materials of encapsulations}
- H10F 19/85: Protective back sheets
- Y02E 10/50: Photovoltaic [PV] energy
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

An electronic device comprises a first encapsulating film in direct contact with a light-receiving and transmitting film and a second encapsulating film in direct contact with a back sheet. The first encapsulating film has a zero shear viscosity greater than that of the second encapsulating film. The back sheet of the electronic device contains fewer bumps than the back sheet of a comparable electronic device having a first encapsulating film with a zero shear viscosity less than or equal to that of the second encapsulating film.

## Claims

### Claim 1

An electronic device comprising:
a top sheet;
a front encapsulant film in direct contact with the top sheet, the front encapsulant film composed of a first ethylene/alpha-olefin copolymer composition having a first zero shear viscosity (ZSV) value;
a photovoltaic module having a top surface in direct contact with the front encapsulant film, the photovoltaic cell having ribbons extending therefrom;
a rear encapsulant film in direct contact with a bottom surface of the photovoltaic module, the rear encapsulant film composed of a second ethylene/alpha-olefin copolymer composition having a second ZSV value, the second ZSV value is from 700 Pa·s to 860 Pa·s and the first ZSV value is 4065 Pa·s;
a backsheet in direct contact with the rear encapsulant film, the backsheet having an unshrunken pre-lamination state and a shrunken post-laminated state, the backsheet imparting a shear stress upon the rear encapsulant film when the backsheet is subject to lamination conditions and moves from the pre-lamination state to the post-lamination state; and
the second ethylene/alpha olefin composition disperses the shear stress such that the shear stress does not reach the photovoltaic module.

### Claim 2 (depends on 1)

The electronic device of claim 1 wherein the electronic device exhibits no bumps.

### Claim 3 (depends on 2)

The electronic device of claim 2 wherein the ribbons are not buckled.

### Claim 4 (depends on 3)

The electronic device of claim 3 wherein the backsheet comprises a layer composed of polyethylene terephthalate.

### Claim 5 (depends on 4)

The electronic device of claim 4 wherein a portion of the front encapsulant film is in direct contact with a portion of the rear encapsulant film.

### Claim 6 (depends on 5)

The electronic device of claim 5 wherein the first ethylene/alpha-olefin copolymer composition is a blend of ethylene/alpha-olefin copolymers;
the second ethylene/alpha-olefin copolymer composition is a blend of ethylene/alpha-olefin copolymers; and
first ethylene/alpha-olefin copolymer composition includes at least one ethylene/alpha-olefin copolymer that is different than the ethylene/alpha-olefin copolymers present in the second ethylene/alpha-olefin copolymer composition.

### Claim 7 (depends on 1)

The electronic device of claim 1, wherein the second ethylene/alpha-olefin copolymer composition has a ZSV value of 860 Pa·s.

### Claim 8 (depends on 7)

The electronic device of claim 7, wherein the first ZSV value is from 3,205 to 3,365 Pa·s greater than the second ZSV value.

### Claim 9 (depends on 1)

The electronic device of claim 1, wherein the second ethylene/alpha-olefin copolymer composition has a ZSV value of 700 Pa·s.

### Claim 10

A process comprising:
providing an assembly in the following order (i) a top sheet, (ii) a front encapsulant film, (iii) a photovoltaic module, the photovoltaic module having ribbons extending therefrom, (iv) a rear encapsulant film, and (v) a backsheet;
providing a first ethylene/alpha-olefin copolymer composition having a first zero shear viscosity (ZSV) value for the front encapsulant film and providing a second ethylene/alpha-olefin copolymer composition having a second ZSV value for the rear encapsulant film such that the second ZSV value is from 700 Pa·s to 860 Pa·s and the first ZSV value is 4065 Pa·s;
subjecting the assembly to lamination conditions;
shrinking, under the lamination conditions, the backsheet;
imparting, with the shrinking, a shear stress onto the rear encapsulant film;
dispersing the shear stress with second ethylene/alpha-olefin copolymer such that the shear stress does not reach the photovoltaic module; and
forming an electronic device.

### Claim 11 (depends on 10)

The process of claim 10 comprising
preventing, with the dispersing, the ribbons from buckling; and
forming an electronic device exhibiting no bumps.

### Claim 12 (depends on 11)

The process of claim 11 comprising
providing a backsheet comprising a layer composed of polyethylene terephthalate.

### Claim 13 (depends on 12)

The process of claim 12 comprising
subjecting the assembly to lamination conditions including a lamination temperature from 120° C. to 170° C.

### Claim 14 (depends on 10)

The process of claim 10, wherein the second ZSV value is 700 Pa·s.

### Claim 15 (depends on 14)

The process of claim 14, wherein the first ZSV value is from 3,205 to 3,365 Pa·s greater than the second ZSV value.