Dark photovoltaic roof for vehicle

Abstract

The present invention is a dark photovoltaic roof for a vehicle having a dark appearance. It is comprised of a first UV transmissive glass layer, a photovoltaic arrangement layer and a second clear glass layer. The photovoltaic arrangement layer is bonded to the first and second glass layers by a first and a second bonding layers respectively. This photovoltaic arrangement goes through a low temperature soldering process and has a dark appearance given by the combination of the solar cell color and the color of the interconnection wires. Advantageously the second bonding layer is dark. This design reduces the dizziness effect and simplifies the roof stack.

Description

DARK PHOTOVOLTAIC ROOF FOR VEHICLEFIELD OF THE INVENTION

[0001] The present invention is part of the laminated glazing field, specifically for the automotive industry.BACKGROUND

[0002] In the last few decades glazing for vehicles has been designed in such a way to provide to the passengers inside the vehicle the feeling of connectivity to the exterior. In this sense, glazing is becoming larger and being important to the aesthetics of the vehicle.

[0003] With glazing increasing in size, technological devices that before were connected to the car body now must be integrated into the glazing. These devices include interior lighting, touch controls for car media, light blinds and variable light transmission films as well as other technologies.

[0004] Photovoltaic elements are another type of these devices that are taking up space in the automotive industry. The market is demanding transportation solutions that are more energyefficient. Not only hybrid and electric vehicles are on game, but the addition of photovoltaic elements also contributes to a greener solution.

[0005] Photovoltaic elements in general terms comprise any type of semiconductor elements that are sensitive to the photoelectric effect. Examples of photovoltaic elements are solar cells of the following types: Heterojunction (HJT), Interdigitated Back Contact (IBC), Passivated Emitter and Rear Contact (PERC), Tandem structures, Tunnel Oxide Passivated Contact (Topcon).

[0006] The individual photovoltaic elements need to be connected to each other forming photovoltaic strings and these strings when connected to each other form photovoltaic arrangements.

[0007] One of the problems with integrating photovoltaic elements to the roof of a vehicle is the appearance. The combination of the photovoltaic element color, the gridlines printed on theelements' surface, the silver wires used for electrical connection, and the spacing between one string and another, may cause dizziness when light reaches a moving vehicle.

[0008] Additionally, the current process of electrically connecting one photovoltaic element to another requires soldering of the electrical connector which increases the risk of damage of the element due to high temperature and mechanical stress. When ribbons, instead of wires, are used to electrically connect photovoltaic elements, they take up space of the surface and unavoidably reduces the active area of the element.

[0009] It would be advantageous to find a solution to the aforementioned problems.BRIEF DESCRIPTION

[0010] The present invention provides a solution to the aforementioned problems by providing a dark laminated roof for a vehicle. The dark laminated roof comprises two glass layers, a first glass layer and a second glass layer. Each one of the glass layers has an exterior surface oriented towards the outside of the laminated glazing, and an interior surface oriented towards the inside of the laminated glazing. A photovoltaic arrangement is disposed in at least one region between the interior surfaces of the first and second glass layers. At least one first bonding layer is arranged between the first glass layer and the photovoltaic arrangement, and at least one second bonding layer is arranged between the second glass layer and the photovoltaic arrangement. The laminated roof has at least one region with the photovoltaic arrangement having light transmission of less than or equal to 5 %, and the exterior color reflectance at an observation angle of 0 degrees has parameter L < 20. This combination of color reflectance range and light transmission results in a laminated roof with dark appearance.

[0011] In one inventive embodiment the dark appearance is achieved by having a photovoltaic arrangement comprised of a plurality of photovoltaic elements and providing black wires that serve to interconnect adjacent photovoltaic elements to each other.

[0012] In another inventive embodiment of the invention the photovoltaic elements are solar cells and wherein the first glass layer interior surface has at least one region having obscuration that is disposed in such a way that it overlaps with the spacing between adjacent electrically connected solar cells.

[0013] Yet in another embodiment of the invention the at least one second bonding layer is opaque, having visible light transmission (Tvis) equal to or lower than 2%, preferably lower than 1% and even more preferably substantially 0%.

[0014] Yet another aspect of the invention is a vehicle comprising the dark laminated roof of this invention.

[0015] The advantages of the present invention are:• Improved aesthetics and eliminated dizziness effect due to dark appearance.• Low temperature soldering process of electrical connector between adjacent photovoltaic elements which reduces thermal stress and therefore lowers the risk of thermal damage on the photovoltaic element.• Low temperature soldering happens before lamination, eliminating the risk of interconnection problems tied to the lamination parameters.• Simple laminated roof stack due to elimination of carrier film needed for low temperature process for photovoltaic elements electrical connection.• Lower risk of deairing issues during lamination of the glazing due to decreased number of encapsulant layers.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] These and other features and advantages of the invention shall be explained in more detail with reference to the embodiments shown in the attached drawings, the embodiments being provided only by way of illustrative and non-limiting examples. Herein,

[0017] FIG. 1 illustrates a schematic view of a vehicle having the laminated roof of the present invention.

[0018] FIG. 2A illustrates the cross section of a stack of layers of a laminated roof for a vehicle in accordance with a generic embodiment of the present invention.

[0019] FIG. 2B illustrates the cross section of a photovoltaic element comprising black wires.

[0020] FIG. 3A illustrates the cross section of a stack of layers of a laminated roof for a vehicle in accordance with one embodiment of the present invention, comprising obscuration.

[0021] FIG. 3B illustrates the cross section of a stack of layers of a laminated roof for a vehicle in accordance with another embodiment of the present invention, comprising obscuration.

[0022] FIG. 4 illustrates the cross section of a stack of layers of a laminated roof for a vehicle in accordance with one embodiment of the present invention, comprising an opaque interlayer .

[0023] FIG. 5A illustrates the cross section of layers of a laminated roof for a vehicle in accordance with one embodiment of the present invention, comprising a coating.

[0024] FIG. 5B illustrates the cross section of a stack of layers of a laminated roof for a vehicle in accordance with another embodiment of the present invention, comprising obscuration, an opaque layer, and a coating.LIST OF REFERENCE NUMERALS1 vehicle2 laminated roof4.1 first bonding layer4.2 second bonding layer6 obscuration8 photovoltaic arrangement10 photovoltaic element12 additional interlayer14 coating16 Spacing20 black wire22 black adhesive24 metal core101 exterior surface of first glass layer102 interior surface of first glass layer103 interior surface of second glass layer104 exterior surface of second glass layer201 first glass layer202 second glass layerDETAILED DESCRIPTION

[0025] As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a product.

[0026] The term “layer”, as used in this context, shall include the common definition of the word, i.e.: a sheet, quantity, or thickness, of material, typically of some homogeneous substance.

[0027] The term “stack” refers to the arrangement in a pile manner of a plurality of layers.

[0028] Laminates, in general, are articles comprised of multiple layers of thin, relative to their length and width, material, with each thin layer having two oppositely disposed major faces, typically of uniform thickness, which are permanently bonded to one and other across at least one major face of each layer. The layers of a laminate may alternately be described as sheets or plies. In addition, the glass layers of a glazing may be referred to as panes.

[0029] In an embodiment, the type of glass for the at least one glass layer or for both glass layers of a laminate that may be used include, but are not limited to, common soda-lime variety typical of automotive glazing as well as aluminosilicate, lithium aluminosilicate, borosilicate, glass ceramics, and various other inorganic solid amorphous compositions which undergo a glass transition and are classified as glass including those that are not transparent.

[0030] The term “glazing” should be understood as a product comprised of at least one layer of a transparent material, preferably glass, which serves to provide for the transmission of lightand / or to provide for viewing of the side opposite to the viewer and which is mounted in an opening in a building, vehicle, wall or roof or other framing member or enclosure.

[0031] Roof glazing is highly effective in this respect. Roof glazing, once limited to an area immediately above the front seat, has been getting larger and larger. We now see roof glazing that comprises a substantial portion of the vehicle roof. These large glazing are known as panoramic roofs.

[0032] The term “vehicle” in the present invention includes, but is not limited to, road vehicles (e.g. cars, busses, trucks, agricultural and construction vehicles, cabin motorbikes), railway vehicles (e.g. locomotives, coaches), aircraft (e.g. airplanes, helicopters), boats, ships, and the like. For instance, the vehicle may be a road vehicle and more particularly a car.

[0033] Photovoltaic elements are comprised of semiconductor elements that are sensitive to the photoelectric effect. A plurality of photoelectric elements is electrically connected to each other forming strings. The photovoltaic strings are also connected to each other forming photovoltaic arrangements. In one embodiment the photovoltaic elements have a size ranging from 100 mm to 210 mm in at least one of its dimensions.

[0034] In one embodiment the plurality of photovoltaic elements are solar cells selected from any of the following: Heterojunction (HJT), Interdigitated Back Contact (IBC), Passivated Emitter and Rear Contact (PERC), Tandem structures, Tunnel Oxide Passivated Contact (Topcon).

[0035] As the market has been demanding greener solutions for transportation, vehicle manufacturers have been facing the challenge of integrating photovoltaic elements, for example, into the vehicle. The challenge increases when the photovoltaic elements need to be embedded into a laminated roof. Current manufacturers are solving this problem by producing photovoltaic elements that are connected to each other either by conductive adhesives such as in the shingling method or by using thin wires forming interconnections among cells. When wires are used for interconnection, they need to be attached to photovoltaic element surface by either soldering at high temperature or by using a carrier film which in by itself comprises the wires.

[0036] Connection of the wires in the carrier film is done during lamination of the carrier film and any additional interlayer with the glass layers in the autoclave. As one may imagine, thecycling times for preparing the strings are high, and the amount of interlayer layers (bonding layers and carrier films) in the laminated glazing stack overcomplicates the assembly and may create problems such as air bubbles trapped between layers.

[0037] Normally, during lamination and autoclave, the interlayers are positioned in between the glass layers forming a stack. The stack is then enclosed into vacuum bags, or vacuum rings also known as channels that are attached to the edge of the stacks such as to provide low- pressure among all the layers of the stack with the intent to remove trapped air within the layers. This step is followed by an autoclave procedure where the stack is placed under low pressure and high temperature for a specific cycling time such as to promote bonding of the interlayers to the glass layers, forming a laminated glazing. When deairing within the layers of the stack is not performed accordingly, air bubbles may get trapped within the layers and problems such as visible bubbles and delamination of one of more layers of the stack may occur.

[0038] Furthermore, the electrical connection of the wires (soldering) to the photovoltaic elements happens during the lamination process, and the quality of the electrical connection is highly dependent to the lamination and autoclave processes i.e., any parameter modification in temperature, pressure, time and dearing parameters may affect the final result.

[0039] The present invention proposes a dark laminated roof 2 for a vehicle 1 comprising two glass layers, a first glass layer 201 and a second glass layer 202. Figure 1 illustrates a top view of a vehicle 1 with the dark laminated roof 2.

[0040] The first glass layer 201 has an exterior surface 101 oriented towards the outside of the laminated roof 2 and an interior surface 102 oriented toward the inside of the laminated roof 2. The second glass layer 202 has an interior surface 103 oriented towards the inside of the laminated roof 2 and an exterior surface 104 oriented towards the outside of the laminated roof 2. A photovoltaic arrangement 8 is disposed in at least one region between the first glass layer 201 and second glass layer 202. At least one first bonding layer 4.1 is arranged between the first glass layer 201 and the photovoltaic arrangement 8, and at least one second bonding layer 4.2 is arranged between the second glass layer 202 and the photovoltaic arrangement 8. This is illustrated in Figure 2 A. The roof has at least one region with photovoltaic arrangement wherein the visible light transmission is less than or equal to 5 %, and the exterior colorreflectance at an observation angle of 0 degrees has parameter L < 20. This combination of color reflectance range and light transmission results into a laminated roof with dark appearance.

[0041] Visible light transmission or transmittance (Tvis) is measured and calculated within the wavelength range of 380nm to 780nm according to the standard IS09050.

[0042] Color reflectance is also measured according to the standard IS09050. Color can be described mathematically. CIELAB is one of the many color spaces and is normally used in automotive and architectural industries. The advantage of the CIELAB color system is that color shifts on the CIELAB diagram are perceived proportionally by the human eye. The CIELAB L*, a*, b* color space mathematically describes all perceivable colors in three dimensions: L* for perceptual lightness, a* for green-red, and b* for blue-yellow. See Hunter Lab, Applications Note, "Insight on Color," Vol. 10, No. 7 (2008). In the CIELAB color space, the L* axis runs from top to bottom. The maximum L* value is 100, which indicates a perfect reflecting diffuser (i.e., the lightest white). The minimum L* value is 0, which indicates a perfect absorber (i.e., the darkest black).

[0043] In one advantageous embodiment the at least one second bonding layer has visible light transmission equal to or lower than 2%, preferably lower than 1% and even more preferably substantially 0%.

[0044] The photovoltaic arrangement 8 of the laminated roof 2 comprises a plurality of photovoltaic elements 10. In one inventive embodiment of the invention the adjacent photovoltaic elements 10 are interconnected to each other by means of black wires 20. The black wires 20 are comprised of a black adhesive 22 surrounding a metal core 24. The metal core may comprise a copper wire such as silver plated copper wire. The conductive adhesive may comprise carbon black. The thickness of the metal core may range from 0.07 to 0.50 mm. In one embodiment, the diameter of the metal core is 0.07, although it could also be 0.15, or 0.28 mm. The conductive coating for instance may range in thickness from 2 pm to 50 pm. Figure 2B illustrates the cross section of a photovoltaic element 10 comprising the black wires 20, wherein the black wires are connected to the back surface of one photovoltaic element 10 and to the front surface of an adjacent photovoltaic element forming at least one photovoltaic string. The photovoltaic strings may be configured to be connected to a junction box external tothe laminated roof 2. The black wires 20 interconnection provides a very homogeneous and dark appearance to the laminated roof and therefore eliminates the problem of dizziness. Additionally, the use of black wires optimizes the quality of the electrical connection among photovoltaic elements. This is because black wires require a low temperature soldering, which in turn decreases probability of mechanical stress and photovoltaic element breakage. The black wires are disposed near the photovoltaic element surface and with low temperature and pressure, the conductive adhesive softens and adheres to the surface of the photovoltaic element resulting in a reliable electrical connection. The conductive adhesive is dark in color, having a black appearance with color reflectance parameter L < 20.

[0045] In another inventive embodiment of the invention, the first glass layer interior surface 102 has at least one region having obscuration 6 disposed in such a way that it overlaps with the spacing 16 between adjacent electrically connected photovoltaic elements 10. This is illustrated in Figure 3 A. The obscuration 6 covering the spaces 16 between the photovoltaic elements 10 when looking from the exterior surface to the interior surface and contributing to a darker appearance of the glazing.

[0046] Alternatively, or additionally, obscuration 6 may also be provided in at least one region of the interior surface 103 of the second glass layer in such a way that the obscuration 6 overlaps with the spacing 16 between adjacent electrically connected photovoltaic elements 10. This is illustrated in Figure 3B. In this case, the laminated roof may have a more homogeneous and dark color when one is looking from inside of the vehicle cabin. Obscuration may be comprised of black enamel printed onto the glass surface or an opaque layer that is disposed in between the glass and the photovoltaic arrangement. This opaque layer could be a tinted layer that is opaque throughout its thickness, or it could be a layer that is printed with an opaque ink, both options of opaque layers serving as obscuration layers.

[0047] In another inventive embodiment of the invention the laminated roof 2 further comprises an additional interlayer 12 disposed in between the second glass layer 202 and the photovoltaic arrangement 8. This is illustrated in Figure 4A. The additional interlayer may comprise a performance film that includes but is not limited to solar control, variable light transmission, increased stiffness, increased structural integrity, improved penetration resistance, improved occupant retention, providing a barrier, tint, providing a sunshade, color correction, and as a substrate for functional and aesthetic graphics. In one inventiveembodiment the additional interlayer comprises a dark film, which helps to conceal the view of the back side of the photovoltaic elements. It results into a darker laminated roof when viewed from inside of the vehicle cabin.

[0048] In another advantageous embodiment the additional interlayer 12 has visible light transmission equal to or lower than 2%, preferably lower than 1% and even more preferably substantially 0%.

[0049] Figure 5A illustrated another embodiment of the invention wherein the external surface 104 of the second glass layer comprises a coating 14 selected from anti-reflection, image projection, anti-fingerprint, low-e, and a combination thereof.

[0050] Figure 5B illustrates an advantageous embodiment of a dark laminated roof comprising obscuration 6 on at least one region of the interior surface 102 of first glass layer 201 such that it overlaps with the spacing 16 in between photovoltaic elements 10 with the purpose of hiding these spaces. Furthermore, the roof comprises an additional interlayer 12 having visible light transmission lower than 2% disposed on the interior surface 103 of second glass layer 202.Additionally, the roof comprises an anti-reflection coating 14 disposed onto the exterior surface 104 of the second glass layer 202. This embodiment is not limiting. Additional features such as additional interlayers, performance films and inserts could be added to the roof without departing from the spirit of the invention. In this sense, in another embodiment the laminated roof of the invention further comprises a touch sensor control disposed on the exterior surface 104 of the second glass layer 202 (not shown in the figure).

[0051] Normally, photovoltaic elements such as solar cells comprise an electrically conductive coating on any one or both major surfaces that is comprised of ITO. ITO coating normally has a blue coloration. In another inventive embodiment of the invention the dark appearance of the laminated roof can be further enhanced by selecting solar cells with darker appearance. For that the plurality of photovoltaic elements 10 are comprised of an electrically conductive coating composed of dark ITO comprising a grey / black coloration.

[0052] The bonding layers have the primary function of bonding the major faces of adjacent layers to each other. The first and second bonding layers (4.1, 4.2) may be selected from any of the following polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), thermoplasticpolyurethane (TPU), polyolefin elastomers (POE), liquid optically clear adhesive (LOCA), or a combination thereof.

[0053] Preferably, the thickness of the bonding layers is comprised between 0.3 mm and 2.0 mm, such as between 0.5 mm and 1.0 mm, e.g., about 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1.0 mm.

[0054] When it is referred to “a glass layer” or “at least one glass layer”, it shall be understood that this shall encompass an arrangement of a single glass layer or multiple glass layers. Any of the first 201 and / or second 202 glass layers may be selected from any of the following soda-lime glass, aluminosilicate glass, borosilicate glass, lithium aluminosilicate glass, and glass ceramics.

[0055] Preferably, the thickness of the two glass layers may vary widely and thus be ideally adapted to the requirements of the individual cases. In an embodiment, the thickness of the two glass layers of the laminated roof of the invention is lower than 5.0 mm, preferably comprised between 0.3 mm and 5.0 mm, such as between 0.5 mm and 4.0 mm or between 1.0 mm and 3.0 mm. Possible examples of thicknesses of the two glass layers are about 1.5 mm, 1.6 mm, 1.7 mm,1.8 mm, 1.9 mm, 2.0 mm, 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm,2.9 mm or 3.0 mm.

[0056] Power generation is highly dependent on the amount of light that is received through the laminated roof and that reaches the photovoltaic arrangement. In other words, the more light reaches the photovoltaic arrangement, the more power it generates. Therefore, advantageously, the first bonding layer is ultraviolet (UV) transmissive and may allow for at least 50 % of light transmission in the wavelength range of 250 to 400 nm.

[0057] The roof comprises at least one region having a photovoltaic arrangement. A photovoltaic arrangement may be disposed such as it takes up less than 95 % of the total surface of the roof, leaving about 5 % or more of the surface without photovoltaic cells. In the regions without a photovoltaic arrangement, a compensation layer can be added comprising the same materials of the first or second bonding layers

[0058] In another aspect of the invention the dark laminated roof is intended to be mounted onto a vehicle. In one embodiment the vehicle comprises a light source illuminating the laminated roof of the invention. The roof is configured to provide illumination by comprising decoupling means onto the interior surface of the second glass layer, the exterior surface of thesecond glass layer, and / or the second bonding layer. These decoupling means act as scattering means. They decouple, scatter light to the interior of the vehicle and provide interior illumination.

[0059] It shall be noted that the purpose of the invention is not limited to the embodiments described above but may be implemented in an entirely different fashion in different embodiments.EXAMPLES

[0060] Example 1 is a dark photovoltaic automotive roof that is curved and comprised of a curved first glass layer (outer), a second glass layer (inner), a photovoltaic arrangement comprising solar cells and two bonding layers. The curved first glass layer is a UV transmissive glass layer (ultra clear soda-lime) that has a black frit enamel as obscuration on the interior surface 102 with a specific design that hides all the string-string interconnection and leaves only the solar cells’ active area visible. The first bonding layer is a UV transmissive PVB or POE. The solar cell arrangement is comprised of solar cell strings interconnected in series or in parallel by a tabbing wire. The strings interconnections are not visible because of the black frit obscuration on the interior surface of the first glass layer. The solar cell strings are comprised of any number of solar cells and busbar wires that connect each cell in series with the adjacent one. Heterojunction busbarless solar cells are used, with an improved darkened finger grid design. Interconnection in series, ie., in between cells, is done using thirty-six or less round thin black wires. These wires have a copper core with a black coating enamel that gives them a black appearance. The number of wires and spacing between them varies depending on the solar cell size and shape. Each cell string can be connected in series or in parallel with the rest of the strings of the roof, however a different connection configuration can be used. The electrical design includes bypass diodes to protect the solar cell arrangement against partial shading. The diodes are placed outside of the laminate in a junction box. The second bonding layer is comprised of PVB or POE and has visible light transmission of less than 2 %, and preferably 0 % that enhances the darker view of the glass to the interior of the vehicle. Finally, the second glass layer (inner) is a clear or solar green glass. The glass may or may not comprisea low-emissivity coating such as low emissivity and anti-reflective coating disposed on the exterior surface (towards the vehicle cabin).

[0061] Example 2 is similar to example 1, except that the first glass layer is 2.1 mm thick ultra clear glass layer. The first bonding layer is 0.76 mm PVB or POE. The photovoltaic arrangement is comprised of heterojunction busbarless solar cells with thickness of 0.2 mm. Rond copper wires with diameter of 0.28 mm and having a carbon enamel coating of between 0.02 mm and 0.04 mm of thickness are used to interconnect the solar cells of each string. A 0.2 mm tabbing wire made of copper with a tin alloy is used to interconnect each string and to transfer the electricity generated by the arrangement out of the laminated roof to the junction box. The second bonding layer is PVB or POE having a thickness of 0.76 mm and having visible light transmission of substantially 0%. The second glass layer (inner) is a curved 2.1 mm glass layer.

[0062] Example 3 is similar to examples 1 and 2 and describes a completely dark laminated roof. The heterojunction busbarless solar cells comprise a special dark ITO coating on the top surface and a special dark painting above the silver grid of the cell. The second glass layer (inner) is curved and is a clear or solar green 2. 1 mm glass layer having a low emissivity coating with anti-reflection properties disposed on the exterior surface 104 (facing the interior of the vehicle).

Claims

CLAIMSWhat is claimed is:

1. A dark laminated roof for a vehicle comprising: at least two glass layers comprising a first glass layer having an exterior surface oriented towards the outside of the laminated glazing, an interior surface oriented towards the inside of the laminated glazing, and a second glass layer having an interior surface oriented towards the inside of the laminated glazing, an exterior surface oriented towards the outside of the laminated glazing; a photovoltaic arrangement disposed in at least one region between the first and second glass layers; at least one first bonding layer, arranged between the first glass layer and the photovoltaic arrangement; at least one second bonding layer, arranged between the second glass layer and the photovoltaic arrangement; and wherein in the at least one region with the photovoltaic arrangement of said roof the light transmission is less than or equal to 5 %, and the exterior color reflectance at an observation angle of 0 degrees has parameter L < 20 .

2. The roof of claim 1, wherein the photovoltaic arrangement comprises a plurality of photovoltaic elements that are comprised of solar cells selected from any of the following Heterojunction (HJT), Interdigitated Back Contact (IBC), Passivated Emitter and Rear Contact (PERC), Tandem structures, Tunnel Oxide Passivated Contact (Topcon).

3. The roof of claim 1 or 2, wherein the photovoltaic arrangement comprises a plurality of photovoltaic elements, wherein adjacent elements are interconnected to each other by means of black wires.

4. The roof of any one of claims 2 to 3, wherein the first glass layer interior surface has at least one region having obscuration disposed in such a way that it overlaps with the spacing between adjacent electrically connected photovoltaic elements.

5. The roof of any one of claims 2 to 4, wherein the plurality of photovoltaic elements is comprised of an electrically conductive coating composed of dark ITO.

6. The roof of any one of claims 1 to 5, further comprising an additional interlayer disposed in between the second glass layer and the photovoltaic arrangement.

7. The roof of any one of claims 1 to 6, wherein said at least one second bonding layer has visible light transmission equal to or lower than 2%, preferably lower than 1% and even more preferably substantially 0%.

8. The roof of claim 6, wherein said additional interlayer has visible light transmission equal to or lower than 2%, preferably lower than 1% and even more preferably substantially 0%.

9. The roof of any one of claims 1 to 8, wherein said at least one first and second bonding layers are selected from any of the following polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), thermoplastic polyurethane (TPU), polyolefin elastomers (PoE), liquid optically clear adhesive (LOCA), or a combination thereof.

10. The roof of any one of claims 1 to 9, wherein the first bonding layer is UV transmissive allowing at least 50 % of light transmission in the wavelength range of 250 to 400 nm.

11. The roof of any one of claims 1 to 10, wherein any of the first and / or second glass layers is selected from any of the following soda-lime glass, aluminosilicate glass, and borosilicate glass.

12. The roof of any one of claims 1 to 11, wherein the external surface of the second glass layer comprises a coating selected from anti-reflection, image projection, anti-fingerprint, low-e, and a combination thereof.

13. The roof of any one of claims 1 to 12, further comprising touch sensor control disposed on the exterior surface of the second glass layer.

14. The roof of any one of claims 3 to 13, wherein the black wires comprise a black adhesive surrounding a metal core.

15. A vehicle comprising the roof of any one of claims 1 to 14.

16. A vehicle of claim 15, comprising a light source that illuminates the roof, wherein the roof is configured to provide illumination by comprising decoupling means onto the interior surface of the second glass layer, the exterior surface of the second glass layer, and / or the second bonding layer.

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