Solar panel using back-contacted solar cells

Abstract

The invention relates to a solar panel comprising: a transparent plate. back-contacted solar cells adhered to the transparent plate. a back-contact foil (302) electrically and mechanically connected to the solar cells, the back-contact foil equipped with a metallisation pattern facing the solar cells, a laminate attached to the back-contact foil. characterized in that the back-contact foil shows one or more flaps (304), the end of the flaps more removed from the transparent plate than from the laminate. The back-contact foil is embedded in encapsulant. By adding flaps to the back-contact foil, it is possible to have the end of the flaps extending out of the encapsulant. This enables, for example, the use of connectors for making electric contact to the end of the flaps.

Claims

1. A solar panel comprising: a transparent plate, back-contacted solar cells adhered to the transparent plate, a back-contact foil electrically and mechanically connected to the solar cells, the back-contact foil equipped with a metallisation pattern facing the solar cells, a laminate attached to the back-contact foil, wherein the back-contact foil comprises one or more flaps, the end of the one or more flaps more removed from the transparent plate than from the laminate, and wherein the one or more flaps are folded over the laminate, and wherein the one or more flaps are folded over a folding line and in which the laminate comprises indents, and wherein at the location of the indents the periphery of the laminate is at a distance from the respective folding lines.

2. The solar panel of claim 1 in which the panel is at least locally curved in two directions.

3. The solar panel of claim 1 in which the transparent plate is a glass plate or a polycarbonate plate.

4. The solar panel of any of claim 1 in which the laminate comprises one or more layers of glass fibres and/or one or more layers of carbon fibres.

5. The solar panel of claim 1 in which wires or bus bars are soldered to the metallization of the one or more flaps.

6. The solar panel of claim 1 in which a layer of an encapsulant adheres the solar cells to the transparent plate.

7. The solar panel of claim 6 in which the encapsulant is EVA.

8. A vehicle equipped with a solar panel according claim 1.

9. The vehicle of claim 8 in which the solar panel is at least part of a bonnet and/or a roof and/or a trunk of the vehicle.

10. A yacht or boat equipped with a solar panel according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is now elucidated using figures, in which identical reference signs indicate corresponding features. To that end:

(2) FIG. 1 schematically shows a bottom view of back-contact foil according to the invention,

(3) FIG. 2 schematically shows a sandwich of a back-contact foil and a laminate according to the invention,

(4) FIG. 3 show schematically a cross section of a solar panel, and

(5) FIG. 4 schematically shows an alternative form of the back-contact foil according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(6) FIG. 1 schematically shows a bottom view of a back-contact foil 102 according to the invention, that is: a view at the side most removed from the transparent plate.

(7) The back-contact foil, or BCF, 102 is a roughly rectangular a substrate film, for example PET, with a patterned conductive layer, typically a copper layer with a thickness of between 50 and 100 m at the top. The foil shows flaps 104 that can be folded downwards along folding lines 106 (away from the transparent plate). A flap can comprise one copper track, or it may comprise several tracks.

(8) It is noted that also another substrate material than PET can be used, such as a polyimide or a polyester film. For the conductive layer normally copper is used, but also (alloys of) aluminium, nickel, gold and silver etc. are known to be used.

(9) FIG. 2 schematically shows a sandwich of a back-contact foil 102 and a laminate 202 according to the invention.

(10) FIG. 2 also shows a view form the bottom side, but now the laminate 202 is placed on the BCF 102. The flaps 104 are folded downwards (towards the viewer). The laminate 202 shows indents 204 to locally increase the distance between BCF and laminate and thereby avoid any of the fibres of the laminate (glass fibres or carbon fibres) to pierce through the flaps of the BCF. Especially carbon fibres can otherwise cause problems, as they are conductive and thus may cause shorts.

(11) FIG. 3 schematically shows a cross section of a solar panel 100 having a transparent plate 401, back-contacted solar cells 301 adhered to the transparent plate 401, a back-contact foil 102 electrically and mechanically connected to the solar cells 301, the back-contact foil 102 equipped with a metallisation pattern facing the solar cells 301, and a laminate 202 attached to the back-contact foil 102. The back-contact foil 102 shows flaps 104, the end of the flaps 104 more removed from the transparent plate 401 than from the laminate 202.

(12) In this embodiment, the flaps 104 are folded along folding lines 106 away from the transparent plate 401. The folding lines 106 are shown as sharp folds. In practice, the folding may also be more gradually. The laminate 202 shows indents 204 to locally increase the distance between BCF 102 and laminate 202, at least at the locations of the folding lines 106 of the flaps 104 and thereby avoid any of the fibres of the laminate (glass fibres or carbon fibres) to pierce through the flaps 104 of the BCF 102. Thus, at the location of the indents 204 the periphery of the laminate 202 is at a distance from the respective folding lines 106, as also shown in FIG. 2.

(13) The indents 204 may be formed in the laminate 202 during creation of the laminate 202 or formed later, for example by cutting the indents 204 into the laminate 202.

(14) The solar panel 100 of FIG. 3 is flat, but in alternative embodiments the solar panel 100 may be curved in one or more directions.

(15) FIG. 4 schematically shows an alternative form of the back-contact foil according to the invention.

(16) Here the flaps 304 do not extend from the BCF 302 but are arranged parallel to the sides of the BCF. As a result thereof the flaps need not be folded so acute, and the stiffness of, for example, PET is of less importance. A slight bend is started at line 306, and extends to the end of the flap 304. The end of the flap is preferably more or less parallel to the BCF 302 and the laminate (not shown in this drawing) and a connector can be clamped on it.

(17) It is noted that, although in FIGS. 1, 2, 3 and 4 the flaps are formed at two opposite sides of the BCF, the flaps can be formed at one, two, three of four sides, and need not oppose each other.

(18) The BCF can have metallization on one side (as normally is the case), but also two sided metallization is known. This enables the use of connectors for two-sided metallization,

(19) Although it is most convenient to place the flap or flaps at the circumference of the BCF, even a flap in the middle of the BCF can be imagined, although this would also imply that a cut-out is made in the laminate.

(20) The different components of the solar panel are encapsulated by cured layers of encapsulant, such as EVA. The transparent plate can be a (flat or curved) plate of glass, polycarbonate, coated polycarbonate, Plexiglass, acrylic, etc.

(21) Electric contacts between the electrodes of the solar cells and the BCF are made by, for example, (cured) conductive glue or by solder, although also laser welding is known to be used.

(22) Electric contact between the flaps and wires and/or bus bars is typically made by (cured) conductive glue, solder or connectors, although also spot welding, laser welding and other techniques may be used.

(23) Many types of photovoltaic cells are known, most based on silicon (monocrystalline and polycrystalline), but also PV cells comprising Gallium, CadmiumTelluride, CopperIndium-diSelenide, perovskites, multi-junction, etc. are known, and many others are expected to follow.