Process of preparing colored solar cells
A process for the preparation of colored solar cells or colored solar cell modules containing a colored polymer film with oriented effect pigments, and colored solar cells or colored solar cell modules prepared by this process.
1. A process of preparing a colored solar cell or colored solar cell module comprising the following steps:
a) a first lamination step of lamination of a polymer film containing one or more effect pigments to a front sheet forming a laminated bilayer,
wherein the polymer film containing the effect pigments has been prepared by melt extrusion of an organic polymer material, wherein the effect pigments are added to the polymer melt before extrusion,
wherein the effect pigments are transparent or semi-transparent, colorless, flake-form substrates, which have been coated with one or more layers of transparent or semi-transparent, colorless materials, and
which effect pigments are reflecting only a part of the incident visible light,
b) optionally cooling down said laminated bilayer,
c) providing a stack of layers comprising the following layers:
C1) optionally one or more front encapsulant films,
C2) one or more solar cells, or an array of solar cells which are electrically interconnected by conducting parts,
C3) optionally one or more rear encapsulant films,
C4) a rear sheet,
on top of said laminated bilayer,
or
providing said laminated bilayer on top of said stack of layers,
d) a second distinct lamination step of laminating said stack of layers to said laminated bilayer.
2. The process according to claim 1 , wherein said stack of layers comprises a front encapsulant film between the polymer film containing the effect pigments and the solar cell(s) or solar cell array, wherein said front encapsulant film does not contain effect pigments.
3. The process according to claim 1 , wherein the rear sheet has a black or dark color and/or said stack of layers comprises an additional sheet or an encapsulant film provided between the solar cell(s) or solar cell array and the rear sheet, wherein said additional sheet or encapsulant film is black or has dark color.
4. The process according to claim 1 , wherein the conducting parts interconnecting the solar cells are colored black or in a dark color prior to the application of the polymer film with the effect pigments.
5. The process according to claim 1 , wherein a grid of dark color is incorporated into the solar cell(s) or solar cell array, said grid covering bright areas including but not limited to the space between the solar cells and the conducting parts.
6. The process according to claim 1 , wherein the polymer film containing the effect pigments and the front and back encapsulant films are selected from the group consisting of polyolefin films, polyethylene copolymer films, EVA films, EBA films, EMA films, EEA films, POE films, BPO films, PVB films, and TPU films.
7. The process according to claim 1 , wherein the front sheet and/or the back sheet is a glass sheet.
8. The process according to claim 1 , wherein the front sheet and/or the back sheet is a polymer sheet.
9. The process according to claim 1 , wherein the solar cells or solar cell modules are selected from the group consisting of amorphous silicon solar cells, mono-silicon solar cells, multi crystalline silicon solar cells, CIGS-solar cells, CdTe-solar cells, III/V-solar cells, II/VI-solar cells, perovskite solar cells, quantum dot solar cells, organic solar cells and dye sensitized solar cells.
10. The process according to claim 1 , wherein the lamination steps a) and d) are carried out by applying heat and/or pressure, or using an adhesive or a binding agent or layer optionally in a vacuum press.
11. The process according to claim 1 , wherein in the lamination steps a) and d) the heating temperature is 130° C. to 160° C.
12. The process according to claim 1 , wherein the effect pigments and/or the polymer film containing the effect pigments have a selective reflection maximum in the visible range of the solar spectrum.
13. The process according to claim 1 , wherein the effect pigments and/or the polymer film containing the effect pigments have an overall transparency of at least 60% for radiation in the range of 260 to 1200 nm.
14. The process according to claim 1 , wherein the effect pigments and/or the polymer film containing the effect pigments have an overall reflectance of <40% for radiation in the range of 260 to 1200 nm.
15. The process according to claim 1 , wherein the effect pigments are selected from the group consisting of pearlescent pigments, interference pigments and multi-layer pigments.
16. The process according to claim 1 , wherein the effect pigments are based on synthetic or natural mica, flake-form glass substrates, flake-form SiO 2 substrates or flake-form Al 2 O 3 substrates.
17. The process according to claim 16 , wherein the effect pigments are based on flake-form substrates, which are coated with one or more layers of metal oxides and/or metal oxide hydrates of Ti, Sn, Si, Al, Zr and/or Zn.
18. The process according to claim 1 , wherein the amount of effect pigments in the polymer film is 0.2 to 40% by weight.
19. The process according to claim 1 , wherein the thickness of the polymer film containing the effect pigments is 5 to 1000 μm.
20. The process according to claim 1 , wherein the polymer film containing the effect pigments is a co-extruded film of two or more layers, one of which contains the effect pigments.
21. A colored solar cell or colored solar cell module prepared by a process according to claim 1 .
22. The process according to claim 1 , wherein the polymer film containing the effect pigments is a co-extruded film of two or more layers, one of which contains the effect pigments, and wherein the stack of layers does not contain a front encapsulant film.