WO2019058149A1

WO2019058149A1 - Roof covering element provided with a solar cell module

Info

Publication number: WO2019058149A1
Application number: PCT/HU2018/000011
Authority: WO
Inventors: Attila GÓDI
Original assignee: Individual
Current assignee: Individual
Priority date: 2017-09-19
Filing date: 2018-03-19
Publication date: 2019-03-28
Anticipated expiration: 2020-03-19
Also published as: AT17532U1; DE212018000327U1; HU5030U

Abstract

The invention is a roof covering element comprising a tile element (10), a solar cell module connected to a front surface (19) of the tile element (10), the front surface (19) facing outwards in case of built-in tile element (10), and an electric connection arrangement connected to the solar cell module, the solar cell module comprises solar cells (12a-12d) being connected in series, the electric connection arrangement comprises a first electric connection module (14a) and a second electric connection module (14b), each connected to a respective extreme solar cell of the solar cells being connected in series, and the front surface (19) of the tile element (10) being of flat configuration at least partially, and the solar cells (12a-12d) being connected to a part of the front surface (19) having flat configuration.

Description

ROOF COVERING ELEMENT PROVIDED WITH A SOLAR CELL MODULE

TECHNICAL FIELD

The invention relates to a roof covering element having a solar cell module. BACKGROUND ART

Nowadays, with the decreasing availability of fossil fuels, alternative energy sources are becoming more and more widely used. Of renewable energy sources, the application of solar energy is straightforward also for private use; accordingly, in addition to their application for large-scale energy generation installations (e.g. solar farms), apparatuses adapted for using solar energy are becoming more and more widespread for home use. This latter usually involves the use of devices mounted on the roofs of family houses.

Approaches wherein each roof covering element comprises a separate solar cell module are also known.

In JP 3609642 B2 a (roof) tile comprising a solar cell is disclosed wherein the tile is specifically configured for receiving the solar cell module. According to this approach a recessed receiving portion that has dimensions exactly corresponding to the dimensions of the solar cell module is formed in the tile. The electric connector is arranged on the side of the solar cell module (prepared for installation) that is inserted into the receiving portion of the tile. Therefore, a groove adapted for receiving the connector is formed in the receiving portion; to provide for the appropriate arrangement of the device this groove has to be formed in the receiving portion such that, if the solar cell module is fitted against the edges of the receiving portion, the connector is exactly received in the groove. By the help of the groove, the connector is led out to one of the tile's edges. In WO 2010/136021 A1 a (roof) tile provided with a solar cell is disclosed also wherein the tile prepared for receiving the solar cell module has a number of special configuration features to allow for receiving the solar cell. In this approach the solar cell module is arranged also in a recessed receiving portion of the tile. On the backside of the solar cell to be attached to the tile the electric connections are connected to a module located on the backside. In the receiving portion of the tile, and also beside the receiving portion thereof there is arranged a respective recess for arranging the backside module and for the sideways passing of the connectors.

An approach similar to the ones described above is disclosed in DE 1010429 A1 ; in this approach a specially configured recess is also formed in the tile for receiving the solar cell module. In a disadvantageous manner, the connector box (junction box) located at the back of the solar cell module can form an obstacle when installing the solar cell module, or can be seated against a tile situated under the tile fitted with the solar cell module (see Fig. 1 of the document). A great disadvantage of the approaches comprising specially configured recesses for receiving the solar cell module is that both the roofing tile and the solar cell module require extremely accurate manufacturing in order that the solar cell module can be properly fitted against the tile.

As with the above solutions, the (roof) tile shown in Figs. 15A-15B of US 6,294,724 B1 is recessed for receiving the solar cell module. The illustrated solar cell module has an undulating shape, i.e. follows the shape of the tile. The application of such a "shape following" solar cell module is described also in DE 29915196 U1. Although these "shape following" units can be applied with tiles having an undulating shape, their great disadvantage is that they are only capable of a much lower power output compared to flat panels.

The approach according to DE 29610674 U1 is illustrated schematically. In the document, a solar cell module attached to a (roof) tile is described. Connectors adapted for making connections to the adjacent solar cell modules start from the back portion of the solar cell module facing the tile, the connectors being passed through bores in the tile to the backside thereof. In the solution according to the document it is not a design consideration for the solar cell module that the tiles have to be installed in an overlapping manner. In Fig. 2 of the document the attachment of the solar cell module during installation is illustrated in a sectional view; in Fig. 2 it can be discerned that the solar cell module is placed (laid) on the most protruding points of a tile having an undulating shape, and is then fixed in that position. This configuration has the disadvantage that dirt (dust/mud) usually accumulates in the space between the solar cell module and the tile, into which space even leaves falling on the roof can be blown. Since this space is in a covered position it cannot become clean efficiently, which may lead to short circuits or defective contacts. The solar cell module is described as a single, integrated unit in the document; its structural details are not disclosed.

In light of the known solutions the need has arisen for a roof covering element having a solar cell module that has a relatively simple structure, and can be manufactured efficiently and at relatively low cost.

DESCRIPTION OF THE INVENTION

The primary object of the invention is to provide a roof covering element, which is free of disadvantages of prior art approaches to the greatest possible extent.

A further object of the invention is to provide a roof covering element having a solar cell module that has a relatively simple structure, so it can be manufactured efficiently and at relatively low cost, while at the same time it has a nearly identical electric power output in comparison to conventional approaches (i.e. which are mounted on a roof afterwards).

Thanks to its relatively simple structure, the roof covering element according to the invention can be manufactured in a simple manner, and is capable of being reproduced with identical results. With using the roof covering element according to the invention results in a more aesthetic roof surface compared to the application of large solar cell panels, while preserving the visual character of tile roofing. With the application of the roof covering element according to the invention there is no need for applying the support structures and solar cell frames applied with large solar cell panels. Furthermore, the application of the roof covering element according to the invention allows for various different roof shapes (for example, non-rectangular shapes), with better use of space compared to large solar panels. The roof covering element according to the invention can be easily integrated into conventional tile systems, by way of example, concrete tile systems. The application of clay tiles is also conceivable, i.e. the tile element of the roof covering element according to the invention can also be implemented as a clay tile. It is more preferable to apply concrete tiles because the generally used clay tile types are too thin for performing the function of a carrier tile (therefore it is conceivable that for such applications the generally used clay tiles should be made thicker). Concrete tiles can comply with the requirements of the standard EN 490 also together with the solar cell module placed thereon, while a different standard (EN 1304) is applicable for clay tiles, and most probable clay tiles together with a solar cell module mounted thereon comply with that standard only in case the widely applied thinned portions are not included in the clay tile. For covering a given roof portion the roof covering element according to the invention can be combined (and is interchangeable) with roof covering elements that have no solar cell modules mounted, and, of course have no wire pass- through openings. As a matter of course, at such locations where cut tiles have to be applied, tiles without a solar cell module are applied. The roof covering element according to the invention can be attached to a roof shell preferably in a watertight manner, in many cases without the application of further tinned components.

Compared to solutions applying adhesively bonded flexible solar cells, the roof covering element according to the invention preferably has better electric efficiency, its power output deteriorates slower, and the solar cells are secured to the roofing tile more reliably. Furthermore, by including the roof covering element (solar tile) fitted with a solar cell module in a series or parallel-connected system - complying with the electric specifications - an electric network of an arbitrary voltage and current level can be provided. In the case of partial shading, the reduction in power output is smaller because a unit is preferably constituted by a single roof covering element.

In contrast to the solutions wherein fixed connections are mounted on the tile, according to the invention the appropriate contacts are provided while applying a flat front surface. According to the invention, furthermore, the connector members and the wires leading up to them are situated in a covered space, under the roof shell, at a location protected from the environmental effects (rain, snow, UV radiation, wind, etc.) that - provided that a modern layer sequence is applied - is situated in a ventilated space between the roof foil and the tiles. The heat transfer characteristics of the roof covering element according to the invention are more favourable in comparison to conventional tiles, i.e. the solution does not raise the inside temperature of the tile element (and thus the temperature of the loft space). The application of the roof covering element according to the invention allows that any one of the roof covering elements (solar tiles) can be replaced individually in the case of a solar cell fault (or a diode fault).

The roof shell system produced applying the roof covering element according to the invention is preferably electrically insulated and provides a high IP rating. The roof covering element according to the invention complies with the applicable standards, among others thanks to the fact that in the roof covering element according to the invention the solar cell module is present as an additional component of the roof shell solution (the tile element of it is a conventional roofing tile of which the structure need not be modified).

The objects of the invention can be achieved by the roof covering element according to claim 1. Preferred embodiments of the invention are defined in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below by way of example with reference to the following drawings, where

Fig. 1 shows, in a spatial drawing, an embodiment of the roof covering element according to the invention from the direction of the front surface, Fig. 2 shows, in a spatial drawing, the embodiment of Fig. 1 from the direction of the back surface,

Fig. 3 shows the embodiment of Fig. 1 from the direction of the back surface,

Fig. 4 is a view depicting the embodiment of Fig. 1 ,

Fig. 5 is a front view of the embodiment shown in Fig. 1 ,

Fig. 6 is a top view of the embodiment of Fig. ,

Fig. 7 is a spatial drawing of a further embodiment of the roof covering element according to the invention, showing the roof covering element from the direction of the back surface, Fig. 8 shows the embodiment of Fig. 7 from the direction of the front surface,

Fig. 9 shows the embodiment of Fig. 7 in a sectional side view taken along the line A-A of Fig. 8,

Fig. 10 is a front view of the embodiment of Fig. 7, not showing the wiring and the electric connector unit,

Fig. 1 1 is the side view of a unit that is applicable to the tile element as shown in Fig. 7, and

Fig. 12 is a rear view of the unit shown in Fig. 11. MODES FOR CARRYING OUT THE INVENTION

In Fig. 1 an embodiment of the roof covering element (roofing element, roofer element) according to the invention is shown in a spatial drawing. In the illustrated embodiment, the roof covering element according to the invention comprises a tile element 10, a solar cell module (photovoltaic module, it can also be called a solar cell arrangement or photovoltaic arrangement) connected (mounted) to a front surface 19 of the tile element 10, the front surface 19 facing outwards in case of built-in tile element 10, and an electric connection arrangement connected to the solar cell module; in the embodiment shown in Fig 1 the electric connection arrangement is connected to the solar cell module through the tile element 10 (for another exemplary possibility for connection see Figs. 7-12). The tile element 10 is for example a concrete tile (roof tile) but can also be a clay tile (roof tile). Since according to the invention, the tile is modified only to a minimal extent (pass- through openings are formed for the interconnections of the solar cell module and the electric connection arrangement, or for example, an indentation is made in one edge, e.g. the upper edge, of the tile, see Fig. 7), the breaking strength of the applied tile is not essentially smaller than the breaking strength of conventional tiles, e.g. concrete tiles. The tile also remains as watertight as it was before the modifications, and thus it conforms to the standard EN 490.

In the embodiment of the invention shown in Fig. 1 the solar cell module comprises (preferably flat) solar cells 12a, 12b, 12c, 12d being connected in series, the electric connection arrangement comprises a first electric connection module 14a (unit) and a second electric connection module 14b (unit), each connected to a respective extreme (extreme-position, outer, outward) solar cells of the solar cells being connected in series (in the embodiment of Fig. 1 these are preferably connected (mounted) to a back surface 21 of the tile element 10 situated opposite the front surface 19 thereof), and the front surface 19 of the tile element 10 being of flat configuration at least partially, and the solar cells 12a, 12b, 12c, 12d being connected to a part of the front surface 19 having flat configuration. In the illustrated embodiment, therefore, the solar cell module (solar module, solar unit) comprises further subassemblies, i.e. solar cells. The solar cell is an independent (self-contained) unit that is capable of generating electricity when irradiated by light based on the operating principle of the crystal forming it and thanks to the electrodes arranged thereon. In the following the manufacturing method and the configuration of the solar cell module mounted on the tile element is presented in relation to an exemplary case wherein the solar cell module is made from the solar cells by lamination. In the arrangement according to the invention, in the embodiment of Fig. 1 the tile element 10 and the solar cells 12a, 12b, 12c, 12d are connected to each other over a large surface area (this also holds true for the embodiment according to Figs. 7-12, i.e. the below described advantages are present in that embodiment, too). This has the great advantage that the solar cell can transfer heat to the tile element over a large surface area, while the air in the ventilated air gap between the tile and the foil located behind it in the mounted state behaves as a high- volume cooling medium for the tile. As a result of that, the solar cells are not heated more than conventional solar arrays, so their power output is reduced to a lesser extent (the more a solar cell module is heated up the more its power output deteriorates). Our measurements indicated that, due to the thermal inertia of concrete the temperature of the laminated backside of the solar cell will be higher by at most 3-4 °C compared to the backside of conventional solar cell panels. According to the invention, therefore, the flat backside of the solar cell is preferably placed on the flat portion of the front surface of the tile element, providing that they are in contact over the largest possible surface area.

The invention can be realized applying any number of series-connected solar cells considering to the electric specifications, i.e. not only with the four solar cells applied in the illustrated embodiments. The term "electric connection arrangement" refers collectively to all electric connection modules, components, etc., i.e. it is a collective term for these. In the roof covering element according to the invention the electric connection arrangement comprises a(n) (first and second) electric connection module. These can be configured in a manner different from the illustrated electric connection modules 14a, 14b (wherein both units comprise a connection cable and a connector member at its end), for example such that one of them has a configuration similar to the electric connection modules 14a, 14b (having a connection cable/solar cable), while the other has, for example, a connector member secured directly onto the back surface of the tile element. It is possible to connect the connector member of the cable connector unit of the adjacent roof covering element to the electric connection module configured this way, i.e. applying a connector member. In relation to this see also Figs. 7-12.

The tile element 10 has a natural, obvious orientation (most tiles may only be built in according to a single orientation). Thereby the tile element 10 also has a well- defined front surface that is situated at the outside when it is built in, and the solar cells 12a, 12b, 12c, 12d are arranged over this surface according to the invention. The solar cells 12a, 12b, 12c, 12d preferably have a square shape (see Fig. 5), in Fig. 1 they are illustrated in a slightly perspective view. The back surface of tiles can have a number of different configurations; in case of the tile element 10 two support elements 22 (mounting tabs, holding members) are formed on its back surface 21 (see e.g. Fig. 3), in addition to that a number of different grooves and support surfaces are usually formed in the back surface of a tile (an exemplary configuration of the back surface is illustrated in Fig. 7, a similar configuration can be applied also for the embodiment of Figs. 1 -6). When the tile element 10 is installed, the two support elements 22 are supported on the tile batten. It is not necessary to provide the tile element applied in the invention with a coating either on the front or on the back surface (side); as adhesive is applied to the front surface for attaching the solar cells (the sides and the water groove can be coated).

The natural vertical orientation of the tile element 10 (and other similar tile elements) is also clear. A fundamental feature of tiles is that they have to be built in in an overlapping manner, i.e. the tiles in any particular row are arranged to overlap the tiles in the row below, that is, the higher-situated tiles slightly cover the ones situated below them. The degree of the overlap depends on the roof inclination angle: the lower the inclination angle, the larger the overlap. Accordingly, the front surface of the tile element will have a portion that will be covered by the corresponding tile in the next row. As it is the lower portion of each tile that covers another tile in a lower row in the roof plane, this overlap region is located in the upper part (as defined by the "natural" orientation of the tile built in the roof plane) of the front surface of any given tile element (see also further below), the height of the overlap region being, provided that the tile element is held in the "natural" upright orientation, is approximately 20-45%, preferably approximately 25-40% of the height of the front surface of the tile element.

In the embodiment of Fig. 1 , furthermore, the roof covering element comprises, arranged in a first row and in a second row, two solar cells in each row (a first and second solar cell 12a and 12b in the row that can be called the "upper row" according to the orientation of the tile element, and a third and a fourth solar cell 12c and 12d in the row that can be termed the "bottom row"). As it is illustrated in Fig. 1 , in this embodiment the two-row solar cell module comprises exactly four solar cells (in a two-by-two arrangement). In Fig. 1 it is also shown that the solar cells 12a, 12b, 12c are arranged in the lower part of the front surface 19 of the tile element 10 (according to the "natural" orientation). Embodiments wherein the solar cell module comprises more or less than four solar cells can also be conceived; however, as it is detailed below, the configuration with four solar cells is particularly preferable. In the embodiment according to Fig. 1 the solar cells 12a, 12b in the first row are connected in series with the respective adjacent solar cells 12c, 12d in the second row (it is shown in Fig. 1 that the solar cell 12a is connected in series with the solar cell 12c, and also solar cell 12b with solar cell 12d), the solar cells 12c, 12d of the second row are connected in series with one another, and (as shown in Fig. 1 , the solar cells 2c and 12d are connected in series by means of a wire element 17b), and the solar cells 2a, 12b of the first row (i.e. extreme solar cells of the series connection) are connected to the first electric connection module 14a and to the a second electric connection module 14b, respectively.

As shown in Fig. 1 , there are electrodes 13 passed (in a direction parallel with the edge of the solar cells) through the solar cells that are implemented utilizing silicon monocrystals or polycrystals. The electrodes 13 also run parallel with the longitudinal side of the tile element 10 and of the front surface thereof (as with the electrodes 33 according to Fig. 8 that run parallel with the longitudinal side of the tile element 30). The longitudinal side of the tile element is the side (edge) which extends vertically when the tile element is set in its natural orientation (there are two such sides or edges, typically these are the longer sides of the tile element; the sides extending horizontally in this orientation are typically the shorter sides that are perpendicular to the longitudinal sides), this side of the tile element is perpendicular to the tile batten applied therewith. The ends of the electrodes 13 are passed outside the cell, these ends are called "connection ends" (or "electrode connection ends"). These connection ends are interconnected between two adjacent solar cells (e.g. the solar cells 12a and 12c) to make the series connection. Likewise, these connection ends are passed into the first (junction) and third (junction) wire elements 17a, 17c arranged beside the first (top) row of the solar cells (essentially vertically oriented thin connection ends run into the wire elements shown in a horizontal orientation in the figure) and into the second wire element 17b arranged beside the second (bottom) row. The wire element 17b is adapted for making the series connection between the solar cells 12c and 12d of the bottom row, while the wire elements 17a and 17c are adapted for making connection to the electric connection modules 14a and 14b, respectively (see below for more details). The wire elements 17a and 17c are of course not interconnected at their adjacent ends but a bypass diode 15, the functionality of which is presented below, is connected to these ends. On both sides of the bypass diode 15 the wire elements 17a and 17c are connected by wire elements to the electric connection modules 14a and 14b, respectively. In the embodiment of Fig. 1 , therefore, the connection ends adapted for connecting the solar cells 12a, 12b, 12c, 12d to one another, to the first electric connection module 14a and to the second electric connection module 14b are arranged on the sides of the solar cells 12a, 12b, 12c, 12d that are perpendicular to its plane. The connection ends are preferably of the same configuration also in the embodiment according to Figs. 7-12. Certain connection ends may also be arranged in an alternative manner. It is also shown in Fig. 1 that in this embodiment the flat portion of the front surface 19 of the tile element 10, i.e. the flat portion covered by the solar cells 12a, 12b, 12c, 12d, has a rectangle (or optionally, preferably to a good approximation, square) shape. In Fig. 1 also the entire front surface 19 is of rectangle shape and has flat configuration. Accordingly, the part of the front surface 19 of the tile element 10 having flat configuration and being covered by solar cells 12a-12d has mutually parallel straight longitudinal edges on opposite sides thereof (this also holds true for the embodiment according to Figs. 7-12; in the natural orientation of the tile element those edges/sides are called the longitudinal edges/sides that connect the upper and bottom edges). As shown in Fig. 1 , a first grooved connection portion 20a and a second grooved connection portion 20b are arranged along the longitudinal sides of the tile element 10, i.e. along the sides interconnecting with the sidewise neighbour of the tile element 10 supported by the same tile batten (the front-facing grooved connection portion 20a is considered not to form part of the front surface). Disregarding such connection portions, and the optionally included other connection portions, the front surface, or the corresponding portion thereof, is rectangular in an embodiment. The rectangle shaped surface thus produced is particularly well suited for arranging solar cells thanks also to the fact that solar cells typically have rectangle or in special cases, square shape (or rectangle-like/square-like shape, see below), and thus can be preferably arranged over a rectangle shaped surface. None of the conventional approaches presented in the introduction applies for connecting the solar cell module a rectangle shape, flat (plane) surface lying in the same plane as the front side of the tile element.

According to an embodiment of the invention, the application of a tile element with such a large flat surface (preferably of a regular, rectangle shape) is also preferable from the aspect of manufacturing technology, because the flat solar cells can be efficiently attached to it, e.g. by adhesive bonding (applying for example a two-component epoxy adhesive). The prefabricated solar cell module (solar cell panel) is attached to the tile element by an intact, completely continuous adhesive bond, the bond running along and around the sides of the solar cell modules lying perpendicular to the flat surface, sealing these edges as well. Thereby it is ensured that moisture cannot enter the space between the two layers (i.e. the solar cells and the front surface of the tile element). The danger of frost damage can thus be avoided. The front surface of the tile element is completely smooth and flat, at least over a part thereof (disregarding naturally occurring surface irregularities; a water groove is optionally also included at the lower edge of the tile element).

In the embodiment illustrated in the drawings, the flat front portion of the tile element is completely covered by the solar glass that is applied for making the solar cell module from the solar cells. This can be observed for example in Figs. 2, 4 and 6 (as well as in Fig. 9); a glass plate 24 is arranged on the front surface of the tile element 10. The applied glass plate is transparent such that the Sun's rays can reach the solar cells. Both tinted and non-tinted glass can be applied. Therefore, a solar glass covering also the so-called overlap region in addition to the solar cells is preferably applied for the solar cells. The overlap region is that part of the flat front surface of the tile element over which no solar cells are arranged (see below in more detail). The lamination layer realized utilizing the preferably applied inner foil, described in detail later on, covers the entire side of the glass plate facing the tile element. The cells and their accompanying wiring are preferably very thin and are arranged between the lamination and the glass plate. The solar cell module thus obtained has a uniform thickness; in the regions with no cells or wiring the small volume remaining there between the lamination and the glass plate is filled up by the applied adhesive.

Therefore (because the solar glass has to be fitted onto the flat front plate) this solution makes manufacturing easier and facilitates waterproofing. If the solar glass covered only the region covered by the solar cells, then, because of the stepped surface shape, a so-called water barrier could be produced between the edges of the overlap region and the region covered by solar cells In a disadvantageous manner, the water barrier could be the starting location of a water intrusion or frost damage. However, according to the above, a uniform- thickness covering is formed by the solar glass on the front surface which is covered by it in its entirety.

Tiles with such a large flat surface is not widely applied, however this configuration has the advantage that the roof covering element fitted with a solar cell module according to the invention preserves its character as a tile and yet it is particularly preferably suitable for the attachment (connection) of the solar cells thereto.

In an embodiment, in the roof covering element, the solar cells are arranged at a distance of 0.1-0.5 cm from one another, and at a distance of 0.2-2 cm, preferably 0.5-2 cm, from the longitudinal edges of the flat portion of the front surface 19 of the tile element 10. An arrangement with proportionally identical dimensioning is shown also in Fig. 1 , and in the embodiment of Figs. 7-12. With such an arrangement the solar cells are arranged as close to one another as possible, i.e. the smallest possible place is used. According to the above, therefore, it is expedient to leave a somewhat greater distance (than the distance between the solar cells) between the edges of the solar cells and the edges of the rectangular front surface in order that the solar cell module can be laminated onto the tile element with sufficient efficiency, for that, however, a gap of 0.5-1 cm is typically sufficient. Keeping to these dimensions will ensure that a tile element with the smallest possible rectangular surface is required for arranging the solar cells. There will be a low amount of unused surface area, which is preferable because, although the roof covering element is as small as possible (an advantage when it is built in), the largest possible amount of its surface is covered with solar cells (as it is presented in detail below, at the top of the tile element it is expedient to include an overlap region not covered with solar cells).

The solar cell modules are typically manufactured in the following manner. First, thin slices (wafers) are cut from the appropriate crystalline base material (e.g. silicon or other monocrystal or polycrystal) that is typically bar-shaped. Then, etchings adapted to receive the electrodes (cf. Fig. 1 , electrodes 13) are made in the slices, and the electrodes, which are made for example of tinned copper strip wire, are soldered (by way of example, applying tin solder) into these etchings (recesses) to produce a solar cell. A plate that is typically made of glass (e.g. low-iron content glass) or a polymer material is then placed over the outside face of the sidewise arranged solar cells. The typical thickness of this plate is approximately 3.2 mm. A foil (e.g. Tedlar foil) is applied to the inside face of the crystals of mutually corresponding solar cells. Typically, a transparent foil (a so-called laminating foil made e.g. of EVA (ethyl vinyl acetate) which is adapted to melt under heat, functioning as an adhesive) is arranged between the solar cell and the foil, as well as between the solar cell and the plate, which however melts and functions as a bonding material when the solar cell module is being made (i.e. when it is subjected to heating in case of lamination). The side lengths of the crystal can be chosen arbitrarily, so the size of the solar cells can be freely chosen corresponding to the flat surface of the tile, and a solar cell module of the desired size can be made carrying out the above described steps. Rectangle, rectangle-like, square or square-like cells with arbitrary side lengths may be applied. Accordingly, in an embodiment of the roof covering element according to the invention the solar cells have square or square-like or rectangle or rectangle-like shape. In such embodiments, the length of the sides of the solar cells is preferably approximately between 120 mm and 160 mm, so their sides can be approximately 130 mm (5 inches) or 156 mm (6 inches) long, or particularly their side length can be between 130 mm and 156 mm. Therefore, if solar cells with a square or square-like shape are applied (as shown in Fig. 1), the side length of the cells is preferably in this range and, if solar cells with a rectangle or rectangle-like shape are applied (as shown in Fig. 8), the two different side length values are in this range. According to the above, therefore, in an embodiment the solar cells (made of an appropriate crystalline material), the inner foil laminated on the inside face (i.e. the side facing the tile element) of all the solar cells arranged on a tile element, and the (solar) glass laminated onto their outside surface are collectively called a solar cell module. In the present embodiment the solar cell module, and therefore the solar cells, are connected (e.g. by adhesion) to the tile element through (by means of) the inner foil (i.e. by means of the outside face thereof). The material of the inner foil is by way of example Tedlar, or other plastic material suitable for making a non-transparent foil. In this embodiment, therefore, the solar cell module further comprises a glass plate (preferably a solar glass plate) covering the entire flat portion of the front surface and the solar cells (in addition to that, the entire flat portion is also covered and bounded by the laminated inner foil). In this embodiment, therefore, in the solar cell module the inner foil, the solar cells and the glass plate are kept together by a lamination applied to them, with the resulting laminated unit being attached to the flat front portion of the tile element. According to the above a laminating foil has to be applied for lamination because the Tedlar foil cannot perform the function of an adhesive (cannot keep together the components). In this embodiment, therefore, the dimensions of the glass plate (and the lamination under it), i.e. its height and width, are the same as the dimensions of the flat portion (with a rectangular configuration their length and width are the same). Therefore, in an example the preferred layer sequence is: solar glass, solar cell (with interconnecting wiring), EVA foil, Tedlar foil; the unit thus obtained is then adhesively bonded to the tile element.

In an embodiment of the roof covering element according to the invention - such as in the embodiment of Fig. 1 - therefore the entire front surface of the tile element 10 has flat (plane) configuration (the grooved connection portions, for example the grooved connection portions 20a, 20b, are not comprised by the front surface). In this embodiment the solar cell module preferably further comprises a glass plate 24 covering the front surface of the tile element 10 and the solar cells 12a-12d arranged on the front surface 19. In this embodiment the solar cell module preferably further comprises an inner foil being laminated onto the glass plate 24 along the side of the glass plate 24 facing the front surface, covering the solar cells 12a, 12b, 12c, 12d, and the solar cell module is connected to the front surface of the tile element 10 by means of (through) the inner foil (an analogous configuration is applied in the embodiment of Figs. 7-12). An embodiment is also conceivable wherein the glass plate is mounted on the front surface of the tile element directly (without lamination), for example applying adhesive bonding such that the solar cells are located between the glass plate and the tile element, however, it is expedient to apply lamination (and thus an inner foil) in this structure, as described above. Lamination provides electrical insulation between the solar cells, the wiring, and the surface of the tile element. ln addition to that, simpler solar cell modules wherein the solar cell module is formed by only a few (e.g. four) solar cells that are directly glued (or otherwise fixed) to the tile element are also conceivable.

By a square-like (rectangle-like) shape it is meant that, when viewed straight on, the shape of the solar cell can be square (rectangle) or rounded/cut-corner square (rectangle). This shape is produced as follows: the crystalline wafers for the solar cells are typically cut from a cylindrical crystal, followed by cutting these circular wafers into square-like or rectangle-like shapes for more efficient use of space. In the case of rounded or cut corners the side length is defined in the same way, as the distance between the straight sections of mutually opposing sides.

It is expedient to apply square-like shaped solar cells with 6-inch-long sides in an embodiment of the invention because this is a standard size (it is a standard size with wide industrial application, and a standard non-flexible solar cell typically applied in systems with large solar panels) with which the manufacturing costs of the roof covering element according to the invention can be reduced further, but no significant manufacturing cost increase is induced by applying square (-like) or rectangle (-like) solar cells cut to a specific size. Arranging only one such cell on a tile would be very inefficient because then the total power output would be very low. In order to arrange four such solar cells with 6-inch sides requires a surface area that is near the standard size of tiles, so it is particularly preferable to arrange four solar cells on each tile. A non-square number of solar cells is may not be arranged on a single tile with efficient use of space. Nine of the above solar cells on a single tile would require so large a surface area with which it would be practically unfeasible to carry out the usual construction tasks. With a tile having a rectangular front surface it is expedient to apply a square number of solar cells also because in such a case the overlap region can be left free of solar cells, the most preferable number of solar cells being four because a tile with a size appropriate for accommodating this number of cells can be easily produced. As far as cells with a square or square-like shape with a side length of slightly less than 6 inches are concerned, the expedient number of such cells to be arranged on a single tile is also four; thus the roof covering element according to the invention can be advantageously applied even with standard-size tile elements. In order to expediently arrange solar cells with a side length of 6 inches (also reserving the appropriate overlap regions for tiles in rows above one another), a tile element 10 having a front surface area of 325^*420 mm is applied in an exemplary embodiment. In this example the horizontal and vertical distance between the solar cells is 2.3 mm and 2.2 mm, respectively, with a zone with a width of 5.7 mm being left free on both sides between cells and the edge of the front surface. In the example, the dimension of the overlap region measured perpendicular to the width direction of the tile is approximately 93-94 mm. In an example the connector units are passed out from the backside of the tile element at a distance of 1 13 mm from the upper edge, and at a distance of 1 15 and 83 mm of both longitudinal sides of the tile element. In an example the combined thickness of the tile element covered by the glass plate is 23 mm, of which 3 mm is the thickness of the glass covering.

Of course, it is expedient to choose an inter-cell distance between 0.1 and 0.5 cm and the distance from the longitudinal edge of the flat front surface 19 of the tile element 10 between 0.5-2 cm also with solar cells having sides with a length of 120-160 mm. Solar cells having a side length in this range can be applied in combination with all components and features presented in the present description.

As it was already mentioned and is also illustrated in Fig. 1 , in the present embodiment an overlap region 23 being arranged beside the region covered by the solar cells 12a, 12b, 12c, 12d and allowing for placing the roof covering elements in an overlapping manner is arranged on the front surface 9 of the tile element 10 arrangement of the overlap region 23 is necessary for overlapping arrangement of the roof covering elements. The size of this region can be adjusted for an ideal or a given application, or it can be adjusted based on the distance between the tile battens. In the most preferred case the covering tile element covers the entire overlap region, and thus, applying the system of roof covering elements provided by an embodiment of the invention it can be achieved that the combined surface area of the fully uncovered solar cells essentially reaches the combined area covered by the system of roof covering elements. The conventional approaches do not intend to achieve this because therein various frame structures are arranged around the solar cell module, or the overlap region is completely left out of consideration. With the four solar cells, the surface area exposed to solar radiation of the roof covering element provides maximal use of space on each roofing tile.

Thus, in the case of systems having the same number of cells and the same orientation the electric power output of the roof covering element according to the invention is only negligibly lower than (almost identical to) the output of the conventional solar panels. This is provided in a particularly preferable manner if the surface area of the tile element not affected by inter-tile overlaps is essentially fully covered by the solar cells (e.g. by applying solar cells with a side length of 6 inches).

Further, in the embodiment according to Fig. 1 the first electric connection module 14a and the second electric connection module 14b are each connected to a respective extreme solar cell of the solar cells being connected in series by means of (through) a first pass-through wire element and a second pass-through wire element passing through the tile element 10, respectively. In this embodiment, furthermore, the first pass-through wire element and the second pass-through wire element are passed through the tile element 10 in the overlap region 23. The overlap region may preferably comprise the region where the wiring connected to the solar cells runs, because this region is not required to be exposed to sunlight. The wiring gets through the tile element typically very close to the solar cells, somewhere near the boundary between the region covered by the solar cells and the overlap region, i.e. in an example the pass-through wire element is passed through the tile element 10 between the region covered by the solar cells 12a, 12b, 12c, 12d and the overlap region 23. In the illustrated embodiment an approach may be applied according to which the wire elements 17a, 17c form a part of the pass-through wire element. The wire elements 17a, 17c are connected to the extreme ones of the solar cells 12a, 12b, 12c, 12d (i.e. the solar cells 12a and 12b), their other ends is connected to another wire element section that is passed through the tile element 10 and connect the wire elements 17a, 17c to the electric connection modules 14a, 14b, respectively, that form a part of the electric connection arrangement. According to another approach, the (branching) wire elements 17a, 17c do not form a part of the pass-through wire element. In this approach the pass-through wire element is a non-branching (straight) wire, with one of its ends being connected to the corresponding electric connection module typically at the cable bushing (in general, at the insulating-mounting element), the other end being connected either to the (branching, junction) wire element 17a, 17c (this latter wire element is a branching one, as illustrated in the figures), or, if a branching is not required, directly to the corresponding solar cell. The pass- through wire element - and, if necessary, the branching wire element implemented either as a part thereof or separately - therefore extend(s) from the above described connection ends hanging out from the solar cells to the electric connection modules.

It is particularly preferable to interconnect the solar cells and the electric connection arrangement applying a pass-through wire element arranged in this manner because in this arrangement the pass-through wire element is not connected to the bottom surface of the solar cells (this preferably also holds true in the embodiment illustrated in Figs. 7-12 to be described in detailed below). Thereby in this embodiment of the invention it is not necessary to configure the tile in any special way in the region under the solar cell module (and thus under the solar cells); which special configuration is widely applied in the known approaches. This allows for the reduction of manufacturing costs, because it is not necessary to produce a tile element custom-configured for solar cell applications, i.e. the same tile element can be utilized as a tile in itself, without the solar cells. This configuration also facilitates assembly, because, in contrast to the known approaches it is not required to arrange the solar cells with high precision in a previously prepared recess. As shown in Fig. 1 , in this embodiment the roof covering element comprises a bypass diode 15 connected in parallel with the solar cells 12a, 12b, 12c, 12d being connected in series. The bypass diode protects the solar cell module of respective roof covering elements from excess current (and from overheating) that may occur in the event of the module being shaded. Inclusion of the bypass diode 15 can also provide protection against such a failure of the solar cell module (or a cell thereof) wherein the faulty cell essentially operates as a load. In case the solar cell module is locally shaded, the module can be overloaded and heated up (due to the current flowing through it). As a result of this, the voltage of the shaded solar cell module is reversed and the solar cell module can be damaged under the effect of the high reverse (closing direction) voltage. Therefore, in order to protect the solar cell modules of shaded roof covering elements a bypass diode, connected in parallel with the solar cell module, can be included. If the polarity of the solar cell module is reversed due to partial shading, the bypass diode becomes forward biased (being of opening direction) and so current flows through it.

By arranging a bypass diode 15, therefore, the interconnected system of roof covering elements according to the invention can be prevented from becoming inoperable due to one (or more) locally shaded or faulty roof covering element(s). Therefore, the system with such a configuration can be operated even until the faulty roof covering element is replaced with a functioning one. Accordingly, applying this embodiment of the invention an extremely efficient system can be made that is resistant against potential failures. The system can of course comprise standalone tiles that do not have a solar cell module arranged on them.

In Fig. 2 the embodiment shown in Fig. 1 is depicted in a spatial rear view. In this view the support elements 22 (protrusions) are shown, which in the installed state are supported against the tile batten. In Fig. 2 there is also shown how the electric connection modules 14a, 14b are connected to the back surface 21 of the tile element 10 in this embodiment. It is shown that in this embodiment the first electric connection module 14a and the second electric connection module 14b are connected to the back surface 21 of the tile element 10 by means of cable bushings 18a, 18b. In other embodiments other insulating-mounting element (e.g. connector box) can be applied that is adapted to provide electric insulation and mechanical attachment in a manner similar to cable bushings; the above described one is therefore an embodiment wherein the first electric connection module and/or the second electric connection module is mounted onto the back surface of the tile element by means of (through) an insulating-mounting element.

Attaching the electric connection module (cable) applying an adhesively bonded cable bushing provides electric insulation, high IP rating and mechanical attachment. In this embodiment, furthermore, it is not necessary to include a connector box, but embodiments applying an electric connector box (connection unit) are also conceivable (an appropriately arranged connector box would not form an obstacle on the backside of the tile element; see also the embodiment of Figs. 7-12). The cable bushings are arranged on the backside in two openings (having a size of, for example, 25 mm) arranged on the tile element by filling up the openings with resin, the openings being adapted for passing the wires through to the cable bushing. Apart from the openings, no additional shape modifications (recesses, grooves etc.) are required in the present embodiment (defined in Figs. 1-6) for arranging the solar cells on the tile element; if a large-sized bypass diode is applied, an additional recess may be required in the middle. In Fig. 2 the electric connection modules 14a, 14b are shown further apart than the pass-through locations of the wire elements leading to them from the front surface (the wire elements are passed through the tile near both ends of the bypass diode 15), but this is only an illustration detail, the wire elements are passed through the tile element typically perpendicularly to the surface of the tile element. The electric connection modules 14a, 14b can be standard cables routinely applied in solar systems, while the connector members 16a, 16b can be for example standard MC4-type solar connectors that are protected against slipping apart and have high IP rating (IP65). It is not absolutely necessary to achieve so high an IP rating because after installation the connector will not be located outdoors. It is more preferable to apply this or other type of connector member compared to conventional solar cell roof covering elements wherein the connector member adapted for interconnecting adjacent roof covering elements is arranged at the side of each roof covering element facing the next one. This contact usually gets dirty in a short time, so it does not provide appropriate connection (the connector element of the embodiment of Figs. 7-12 is also arranged in a covered manner, i.e. not arranged outdoors).

The distance between the electric connection modules 14a, 14b is therefore shown to be relatively large in Fig. 2 only for better comprehension. The wire element can also be passed through the tile element 10 obliquely, in which case such a distance can be achieved but it is not expedient. The electric connection modules 14a, 14b are therefore in most cases located (and attached to the back surface 21 of the tile element 10) much closer to each other. However, the distances between the cable bushings 18a, 18b and the support elements 22 are illustrated at real proportions in Fig. 2. Since the side length of the illustrated solar cells 12a, 12b, 12c, 12d is, by way of example, approximately (to a good approximation, i.e. +/- 1 mm) 156 mm (6 inches), contemplating the proportions it can be seen that a typically applied tile batten, having a width of 5 cm, can be fitted between the cable bushings 18a, 18b and the support elements 22, so no modification of the structure is required for the installation of the roof covering element as implemented according to this embodiment (this can also be the case with a solar cell side length smaller than 6 inches). Thus, thanks to their configuration all of the components can be fit into the space left by the tile batten even at the rafters, because the tiles are slightly spaced apart from the rafters by the tile batten, making room for passing the electric connection modules. Instead of cable bushings a connector box may also be applied (also in the case wherein all the other configuration features are the same as in Figs. 1-6), but in this configuration it is more preferable to apply cable bushings. In addition to providing contact protection, the cable bushings - adhesively bonded to the concrete surface - also prevent the electric connection module from being torn out.

In Fig. 3 the tile element 10 is shown in a rear view (the support elements 22 are shown in more detail). The first and second connector members 16a, 16b, also illustrated in the previous drawings, are clearly shown in Fig. 3. The grooved connection portion 20b adapted for being connected to the grooved connection portion 20a of an adjacent roof covering element is also shown. Thanks to the grooved configuration, the roof covering element in itself provides a fully watertight covering (watertightness is also a feature of the completed roof shell, not only of the individual roof covering elements). In addition to that, the roof covering element is also protected against storms, i.e. has wind uplift protection preferably without being secured by screws or storm clamps thanks to its own weight. Under a roof inclination angle of 45 degrees usually no screwing down or storm clamps are necessary in the inside of the roof field. Closer to the edges of the roof, however, it may become necessary to secure the roof covering elements even under a roof inclination angle of 45 degrees. Without boring a hole through the tile this can be provided applying roof clamps. ln Fig. 4 the embodiment of Fig. 1 is shown in side view. In Fig. 4 it is shown to what extent the support elements 22 protrude from the plane of the backside of the tile (to the extent that is usual with other tile types). In addition to that, the electric connection module 14a protruding from the back surface 21 and the glass plate 24 arranged over the front side is also shown.

In Figs. 5 and 6, the embodiment of Fig. 1 of the roof covering element is shown in front and top plan view, respectively. As with Fig. 1 , in Fig. 5 it is illustrated that, in contrast to a number of conventional approaches, in this embodiment of the invention the solar cells are attached to the tile independently, without a frame structure. As with Fig. 4, the glass plate 24 is also shown in Fig. 6. This also allows for the application of the simple wiring utilized in the illustrated embodiment of the invention.

In Figs. 7-12 a further embodiment of the roof covering element according to the invention is illustrated. The following components are also comprised in this embodiment of the roof covering element (it may have other features introduced above with which it is compatible). In the embodiment of Figs. 7-12 the roof covering element comprises a tile element 30, a solar cell module connected to a front surface 39 of the tile element 30 facing outwards in case of built-in tile element 30, and an electric connection arrangement connected to the solar cell module. In this embodiment the solar cell module comprises first, second, third, and fourth solar cells 32a, 32b, 32c, 32d being connected in series, the electric connection arrangement comprises a first electric connection module 34a and a second electric connection module 34b, each connected to a respective extreme solar cell of the solar cells connected in series, and the front surface 39 of the tile element 30 being of flat configuration at least partially, the solar cells 32a-32d being connected to a part of the front surface 39 having flat configuration. In the embodiment of Figs. 7-12 the entire front surface of the tile element 30 has flat configuration; in the illustrated embodiment an indentation 45 adapted for receiving a preferably applied electric connector unit 31 (electric junction unit) protrudes into the flat front surface.

The most significant feature of the embodiment of Figs. 7-12 differentiating it from the embodiment of Figs. 1-6 described above is the configuration of the connection arrangement. Accordingly, in the embodiment illustrated in Figs. 7-12 the first electric connection module 34a and the second electric connection module 34b are each connected to a respective extreme solar cell of the solar cells being connected in series by means of (through) a first interconnection wire element and a second interconnection wire element that being arranged along the front surface 39 of the tile element 30 (for a first interconnection wire element 48a and a second interconnection wire element 48b see Fig. 8). In this embodiment, therefore, the connections between the first electric connection module 34a, the second electric connection module 34b and the corresponding solar cells are provided by the interconnection wire elements that are run along the front surface 39 of the tile element 30. It is expedient to apply flat wires, for example, the ribbon (band) wires shown also in Fig. 8, as interconnection wire elements and as wire elements 37a- 37c. In certain embodiments (such as in the illustrated embodiment) the interconnection wire element runs between the tile element and the glass plate secured to its front surface (provided with lamination), which is another reason why ribbon wires are expedient. A distinction is made between the interconnection wire element and the (branching) wire elements 37a, 37c. The interconnection wire element is a non-branching (single) wire, with one of its ends being connected to the corresponding electric connection module (at the electric connector unit or directly), the other end being connected either to the (branching) wire element 37a, 37c (this latter wire element is a branching one, as illustrated in the figures), or, if a branching is not required, directly to the corresponding solar cell. The interconnection wire element - and, if required, the branching wire element - therefore extends from the above described connection ends hanging out from the solar cells 32a-32d to the electric connection modules.

As illustrated by Fig. 8, in the embodiment of Figs. 7-12 the first electric connection module 34a and the second electric connection module 34b are connected to the first interconnection wire element 48a and the second interconnection wire element 48b, respectively, by means of (through) an electric connector unit 31. In addition to that, in the embodiment of Figs. 7-12 an indentation 45 (notch, cut, recess) is formed along the edge (side) of the front surface 39 of the tile element 30, and the electric connector unit 31 (or, to use another term - also used to refer to the element providing connection applied in the configuration according to Figs. 7-12 - an electric connector [junction] box) is arranged in the indentation 45.

As illustrated also in Fig. 8, in an embodiment of the invention the indentation 45 is formed in the overlap region 43. This way, provided that the tiles are laid in an overlapping manner, the indentation 45 and the electric connector unit 31 therein are covered by a tile element in the next row. This is preferable from both a technological and an aesthetic aspect because the connection point (connection unit) is protected against the weather, dust and dirt, while the electric connector unit 31 is not visible even if a non-transparent lamination foil is not applied. In the embodiment illustrated in Figs. 7-12, furthermore, the indentation 45 is formed in the edge of the overlap region 43 being opposite the solar cells 32a-32d; it is thus arranged in the most protected place. According to the above, the overlap region is formed beside the region covered by the solar cells, i.e. its side lying opposite the solar cells is the side of the tile element located at the top in the figures (covered by the adjacent overlapping tile). The indentation is most expediently formed here.

The first electric connection module 34a and the second electric connection module 34b applied in the embodiment of Figs. 7-12 are therefore each connected to a respective extreme solar cell of the solar cells being connected in series by means of the electric connector unit 31 (see Fig. 8). The basic function of the electric connector unit 31 is to provide electric connection (by means of wires) between the electric connection modules 34a, 34b and the solar cells of the solar cell module. The features of the electric connector unit 31 are described in detail below. As shown in Fig. 7, a first connector member 36a and a second connector member 36b is arranged at the free end of the electric connection module 34a and 34b, respectively. The electric connection modules 34a, 34b have essentially the same configuration as the connector units 14a, 14b described above, but are connected to the wiring of the solar cell module in a different manner. In Fig. 7 support elements 42 (protrusions) are also shown that are formed on the backside of the tile element 30 and are adapted for supporting the tile element 30 on a tile batten. In Figs. 7 and 8, respectively, there are shown first and second grooved connection portions 40a, 40b being arranged along the longer sides of the tile element 30 and being configured in a similar manner as the grooved connection portions 20a and 20b (but in contrast to them do not extend all along the longer side of the tile element 30). In addition to that, on a back surface 41 (backside) of the tile element 30 - essentially in the region bounded by the grooved connection portion 40a, the support elements 42, the electric connector unit 31 , the grooved connection portion 40b and the bottom part of the tile element 30 - Fig. 7 shows a number of recesses, grooves, shapes and protrusions/thickenings (the latter defining the total thickness of the element) that are formed in the concrete tiles similar to the tile element 30 (usually clay tiles also have such features, but the ones shown in Fig. 7 are characteristic of concrete tiles): This is not relevant for the configuration details (solar cell module, connection arrangement, etc.) that are essential to the subject matter of the invention. Fig. 8 shows the embodiment of Fig. 7 from the direction of its front surface (i.e. the side of the tile element 30 facing outwards). Accordingly, in Fig. 8 there are shown solar cells 32a, 32b, 32c, 32d forming the solar cell module and being arranged on the front side of the tile element. As with the solar cells 12a, 12b, 12c, 12d, these are connected in series with each other (the solar cells 32a, 32b, 32c, 32d are connected one after the other, and the extreme solar cells 32a and 32b are directly connected to the connector units 34a, 34b); and first, second and third wire elements 37a, 37b and 37c are also arranged in an analogous manner with the wire elements 17a, 17b, 17c.

The solar cells 32a-32d are configured in a very similar way as the solar cells 12a- 12d. Unlike these, however, the solar cells 32a-32d do not have a square-like shape but a rectangular shape (their width dimension in the figure is greater than their height; for more information on that see the section below describing the exemplary dimensions). Accordingly, the corners of the solar cells 32a-32d are not cut off. Vertical electrodes 33 (or, in a technical term commonly used in the field, "bus bars") as well as horizontal components extending perpendicular thereto (called "fingers" in the jargon of the field) can also be observed on these. Fig. 8 is a front view showing certain components and the electric connector unit 31 located above the solar cells 32a-32d in dashed lines because they are obstructed from view in the illustrated embodiment (preferably by the foil laminated on the inside of the front glass plate fitted against the tile element 30). In Fig. 8 therefore it is shown that the arrangement of the indentation 45 adapted for receiving the electric connector unit 31 and the electric connector unit 31 itself inside the indentation 45. In Fig. 8 the front surface 39 of the tile element 30 and the overlap region 43 that is situated at the top part of the front surface 39 (in the "natural" orientation of the tile) and is adapted to allow for laying the tile elements 30 on a roof in an overlapping manner are indicated. As illustrated in Fig. 8, the rectangular indentation 45 shaped to match the arrangement of the electric connector unit 31 protrudes into the overlap region 43. It therefore reduces only the surface area that is to be covered by another tile but does not reduce the useful surface area of the tile. Forming the indentation 45 for the purpose of receiving the electric connector unit 31 thus does not have any disadvantage.

The function performed by the electric connector unit 31 can also be comprehended based on Fig. 8. Unlike the wire elements 17a and 17c illustrated in Figs. 1-6, the wire element 37a is arranged slightly further away from the solar cells 32a-32d than the wire element 37c (the function of the wire elements is not affected by this; in an example the wire elements are implemented as a 5-mm- wide strip [band] wire). The wire element 37b is arranged in a similar manner as the wire element 17b.

In Fig. 8 there is shown in dashed lines a first interconnection wire element 48a adapted for interconnecting the solar cell 32a and the electric connector unit 31 through the wire element 37a and a second interconnection wire element 48b adapted for interconnecting the solar cell 32b and the electric connector unit 31 through the wire element 37c that are both obstructed from view due to the application of the non-transparent foil, i.e. the electric connection between the solar cells 32a-32d and the electric connector unit 31 is illustrated. Due to being covered by the non-transparent foil these are not shown (not visible) in Fig. 10 that also shows a front view. Like the interconnection wire element 48a, 48b, the wire elements 37a-37c are also arranged along the front face of the tile element (a foil may be inserted under them), and have preferably flat configuration. Accordingly, the electric connector unit 31 is adapted for providing that the interconnection wire elements 48a, 48b and the electric connection modules 34a, 34b are electrically connected. In Fig. 8 there is not separately shown a bypass diode that is connected between the wire elements 37a and 37c and is arranged in a manner analogous to the bypass diode 15. This is because the bypass diode is inserted between the two outputs in the electric connector unit 31.

In Fig. 9 the roof covering element of Figs. 7-8 is shown in a side elevation sectional view. In Fig. 9 the glass plate 44 adapted for covering the entire front surface (fitted with the solar cells 32a-32d) is shown, and the tile element 30 bearing the glass plate. The section illustrated in Fig. 9 crosses the electric connector unit 31 (according to section A-A of Fig. 8), so the cross section of the unit can be seen behind the glass plate 44 in the top part of the figure. The wiring (i.e. the wire elements 37a, 37b, 37c and the interconnection wire elements 48a, 48b), the solar cells 32a-32d, and the lamination are located between the glass plate 44 and the tile element 30, these cannot be seen in side view. In an example, the thickness of the applied solar cells is approx. 0.2 mm, so they cannot be seen in the figure because they are much thinner than the glass plate. Accordingly, the wiring is lead out from the solar cells 32a-32d (more accurately, from the extreme solar cells 32a and 32b) to the electric connector unit 31 between the glass plate 44 and the tile element 30.

In Fig. 9 the support element 42 is also shown because it is not obstructed from view when the section is viewed from the appropriate direction. Like in Fig. 7, in Fig. 9 certain structural details of the tile element 30, i.e. grooves and recesses, are illustrated. As it was discussed in relation to Fig. 7, because they are formed/arranged on the backside of the tile element 30, these latter are not relevant for the arrangement of the solar cell module. As shown also in Fig. 9, the electric connector unit 31 essentially does not protrude from the back surface of the tile element 30, so the installation of the roof covering element on a tile batten is not affected by the electric connector unit 31. ln Fig. 10 an arrangement corresponding to the one shown in Fig. 8 is illustrated, not showing the wiring and the components of the electric connector unit that are preferably obstructed from view. The non-transparent foil that is laminated onto the backside of the solar cells preferably covers the entire front surface 39, so it obstructs the electric connector unit 31 from a front view (from the direction of the glass plate 44). The non-transparent foil laminated onto the backside of the solar cells is located behind the wiring from the glass plate 44; in order to conceal the wiring (the wire elements 37a, 37b, 37c and the interconnection wire elements) either the foil (that is appropriately oversized) is folded back or separate, appropriately dimensioned pieces of non-transparent foil are inserted between the glass plate and the wiring.

Accordingly, there can also be arranged a foil between the front surface of the tile element and the interconnection wire elements that are arranged along the front surface in the embodiment according to Figs. 7-12 (i.e. the inclusion of the foil does not change that the interconnection wire element is arranged along the front surface). The wires (in this case, the interconnection wire elements 48a, 48b) are preferably passed through the foil (that is laminated onto the backside of the solar cells) near the electric connector unit 31. On the side of the glass plate 44 facing the tile element 30 a preferably non-transparent plastic foil, for example Tedlar foil is applied (as the covering material), which can be preferably laminated onto the arrangement utilizing a laminating foil (e.g. EVA foil which also constitutes the adhesive material). Wiring can be preferably concealed also in the embodiment according to claims 1-6.

Using the arrangement of Figs. 7-12 in an example the solar cells 32a-32d have a height of 124 mm and a width of 143 mm, i.e. they have a rectangle shape (unlike the solar cells 12a-12d of Fig. 1 the corners of the solar cells 12a-12d are not cut off). In the example, the front side of the tile element (not counting the grooved connection portion 40a) has a width of 298 mm and a height of 420 mm, the solar cells 32a-32d being arranged at 2 mm from each other, i.e. the adjacent cells are spaced apart by this amount. In the example, the solar cells 32a-32d are preferably arranged at a distance of 5 mm from the longitudinal edges of the front side, and at a distance of 10 mm from the lower edge (not counting the water groove). As shown in the figure, the indentation adapted for receiving the electric connector unit 31 preferably has a rectangle shape, with a width of 72 mm and a length (i.e. the dimension taken along the longitudinal direction of the tile element 30) of 78 mm in the example. In the arrangement according to Fig. 8, which is asymmetrical with respect to the wire elements 37a, 37c, the wire elements 37a and 37c preferably extend at a distance of 15 mm and 5 mm, respectively, from the solar cells 32a and 32b. In an example, the grooved connection portions 40a protrude from the front surface to a distance of 32 mm, i.e. this is the width of their grooved connection surface. According to the example, the dimension of the overlap region is as measured perpendicular to the width direction of the tile is approximately 160 mm.

In an example the following thickness values are applied: the thickness of the tile element 30 (measured in a region with no groove or recess) is 15.3 mm, the total thickness of the roof covering element measured at the same location is 22.3 mm, the thickness of the glass plate 44 (plus the thickness of the adhesive layer, if it has a relevant thickness) is 7 mm; the thickness of the electric connector unit 31 being approximately the same as the thickness of the tile element 30 that in the example is 15.8 mm. In an example, the electric connector unit 31 is not placed symmetrically on the front surface 39 of the tile element 30, its centre line extending at 166 mm from the left edge of the tile element 30 as seen in the figure.

Figs. 1 1- 2 show a side and rear view, respectively, of the unit of the roof covering element that is applied to the tile element. The illustrated unit comprises the laminated structure (laminated unit) wherein the solar cells 32a-32d and the wiring are laminated with the glass plate 44 (covered by a non-transparent inner foil at the side that will face the tile element 30), and the electric connector unit 31 is attached (e.g. by adhesive bonding) and electrically connected to the completed laminated unit and to the interconnection wire elements passed out therefrom.

The unit of Figs. 1 1-12 therefore further comprises the electric connector unit 31 (making up a laminated unit provided with the electric connector unit), as well as the electric connection modules 34a, 34b that are connected therein and is fitted with respective connector members 36a, 36b. Accordingly, in Figs. 1 1-12 the connection of the electric connector unit 31 to the glass plate 44 (provided with solar cells laminated thereon) is illustrated (in Fig. 12 it is shown that the electric connector unit 31 is attached to the backside of the glass plate), the unit thus obtained can preferably be attached (e.g. by adhesive bonding) as a single piece to the tile element 30. In Fig. 1 1 the above described unit is shown in side view (which can also be a partial sectional view depending on the details shown). Like in Fig. 9, it can be observed in the figure that the solar cells and the foil laminated onto the backside of the glass plate 44 (the side facing the electric connector unit 31) form so thin a layer (relative to the thickness of the glass plate 44) that it cannot be discerned in the figure. The tile elements described in relation to the figures above are so-called flat- geometry, straight-cut tiles with side grooves.

The manner of the industrial applicability of the invention follows from the features of the invention described above. As it is apparent from the above description, the invention realizes the objects set before it in an extremely advantageous manner compared to the state of the art. The invention is, of course, not limited to the preferred embodiments described in details above, but further variants, modifications and developments are possible within the scope of protection determined by the claims.

Claims

A roof covering element comprising

- a tile element (10, 30),

- a solar cell module connected to a front surface (19, 39) of the tile element (10, 30), the front surface (19, 39) facing outwards in case of built-in tile element (10, 30), and

- an electric connection arrangement connected to the solar cell module, c h a r a c t e r i s e d in that

- the solar cell module comprises solar cells (12a-12d, 32a-32d) being connected in series,

- the electric connection arrangement comprises a first electric connection module (14a, 34a) and a second electric connection module (14b, 34b), each connected to a respective extreme solar cell of the solar cells (12a- 12d, 32a-32d) being connected in series, and

- the front surface (19, 39) of the tile element (10, 30) being of flat configuration at least partially, and the solar cells (12a-12d, 32a-32d) being connected to a part of the front surface (19, 39) having flat configuration.

The roof covering element according to claim 1 , characterised by comprising, arranged in a first row and in a second row, two solar cells (12a-12d, 32a-32d) in each row.

The roof covering element according to claim 2, characterised in that

- the solar cells (12a, 12b, 32a, 32b) of the first row are connected in series with the respective adjacent solar cells (12c, 12d, 32c, 32d) of the second row,

- the solar cells (12c, 12d, 32c, 32d) of the second row are connected in series with one another, and

- the solar cells (12a, 12b, 32a, 32b) of the first row are connected to the first electric connection module (14a, 34a) and to the second electric connection module (14b, 34b), respectively.

4. The roof covering element according to any of claims 1-3, characterised in that the connection ends adapted for connecting the solar cells (12a-12d, 32a-32d) to one another and/or to the first electric connection module (14a, 34a) and/or to the second electric connection module (14b, 34b) are arranged on the sides of the solar cells (12a-12d, 32a-32d) that are perpendicular to its plane.

5. The roof covering element according to any of claims 1-4, characterised in that

- the part of the front surface (19, 39) of the tile element (10, 30) having flat configuration and being covered by the solar cells (12a-12d, 32a- 32d) has mutually parallel straight longitudinal edges on opposite sides thereof, and

- the solar cells (12a- 2d, 32a-32d) are arranged at a distance of 0.1-0.5 cm from one another, and at a distance of 0.2-2 cm from the longitudinal edges.

6. The roof covering element according to any of claims 1-5, characterised in that the solar cells (12a-12d, 32a-32d) have square or square-like or rectangle or rectangle-like shape.

7. The roof covering element according to claim 6, characterised in that lengths of the sides of the solar cells (12a-12d, 32a-32d) are approximately between 120 mm and 160 mm.

8. The roof covering element according to any of claims 1-7, characterised by comprising a bypass diode (15, 35) connected in parallel with the solar cells (12a-12d) being connected in series.

9. The roof covering element according to any of claims 1-8, characterised in that the entire front surface (19, 39) of the tile element (10, 30) has flat configuration.

10. The roof covering element according to claim 9, characterised in that the solar cell module further comprises a glass plate (24, 44) covering the front surface (19, 39) of the tile element (10, 30) and the solar cells (12a-12d, 32a-32d) arranged on the front surface (19, 39).

11. The roof covering element according to claim 10, characterised in that the solar cell module further comprises an inner foil being laminated onto the glass plate (24, 44) along the side of the glass plate (24, 44) facing the front surface (19, 39), covering the solar cells (12a-12d, 32a-32d), and the solar cell module is connected to the front surface (19, 39) of the tile element (10, 30) by means of the inner foil. 2. The roof covering element according to any of claims 1-11 , characterised in that an overlap region (23, 43) being arranged beside the region covered by the solar cells (12a-12d) and allowing for placing the roof covering elements in an overlapping manner is arranged on the front surface ( 9, 39) of the tile element (10, 30).

13. The roof covering element according to any of claims 1-12, characterised in that

- the electric connection arrangement is connected to the solar cell module through the tile element (10), and

- the first electric connection module (14a) and the second electric connection module (14b) are connected to a back surface (21) of the tile element (10) being opposite the front surface (19) thereof.

14. The roof covering element according to claim 13, characterised in that the first electric connection module (14a) and the second electric connection module (14b) are each connected to a respective extreme solar cell of the solar cells being connected in series by means of a first pass-through wire element and a second pass-through wire element passing through the tile element (10), respectively.

15. The roof covering element according to claim 14 in combination with claim 12, characterised in that the first pass-through wire element and the second pass-through wire element are passed through the tile element (10) in the overlap region (23).

16. The roof covering element according to any of claims 13-15, characterised in that the first electric connection module (14a) and/or the second electric connection module (14b) is connected to the back surface (21 ) of the tile element (10) by means of an insulating-mounting element. 17. The roof covering element according to claim 16, characterised in that the insulating-mounting element is a cable bushing (18a, 18b) or a connector box.

18. The roof covering element according to any of claims 1-12, characterised in that the first electric connection module (34a) and the second electric connection module (34b) are each connected to a respective extreme solar cell of the solar cells being connected in series by means of a first interconnection wire element (48a) and a second interconnection wire element (48b) being arranged along the front surface (39) of the tile element (30). 19. The roof covering element according to claim 18, characterised in that the first electric connection module (34a) and the second electric connection module (34b) are connected to the first interconnection wire element (48a) and to the second interconnection wire element (48b) by means of an electric connector unit (31). 20. The roof covering element according to claim 19, characterised in that an indentation (45) is formed along the edge of the front surface (39) of the tile element (30), and the electric connector unit (31) is arranged in the indentation (45).

21. The roof covering element according to claim 20 in combination with claim 12, characterised in that the indentation (45) is formed in the overlap region

(43).

22. The roof covering element according to claim 21 , characterised in that the indentation (45) is formed in the edge of the overlap region (43) being opposite the solar cells (32a-32b).