The present invention relates to an improved photovoltaic panel.

It is known that a photovoltaic panel is an optoelectronic device comprising a matrix of photovoltaic cells capable of converting the incident solar energy into electrical energy by means of a photovoltaic effect.

Traditional photovoltaic panels are not completely satisfactory as they are quite expensive and complicated to install, as well as generally need dedicated external equipment (for example inverters) which must be properly connected to the electricity network.

Furthermore, the aesthetic yield of traditional photovoltaic panels is low and, therefore, their diffusion, particularly in the urban domestic context, is rather limited. In particular, currently, there are regulations, guidelines and/or regulations (generally proposed by local administrations) that limit the installation of these panels in areas of landscape and/or cultural interest, such as historic centers, or in the vicinity of monuments.

Currently, solar panels are installed only in a vertical or inclined position, generally on roofs, on walls of buildings or on support bases, thus limiting the possibility of using the panels themselves.

US 2015/0121780 describes a walkable photovoltaic panel comprising a series of solar cells encapsulated between a pair of layers of encapsulant, in turn inserted between two layers of laminated glass. In particular, in the described photovoltaic panel the encapsulating material can be colored.

WO2017/107783 describes a method for the preparation of a self cleaning film.

The object of the present invention is to propose a photovoltaic panel capable of solving, at least in part, the drawbacks of traditional solutions.

Another object of the invention is to propose a panel which can be installed in a horizontal or substantially horizontal position. Another object of the invention is to propose a panel which can be used as floor.

Another object of the invention is to propose a panel that can be walked on.

Another object of the invention is to propose a panel, configured to be walked on, which is optimized from a constructive and functional point of view.

Another object of the invention is to propose a photovoltaic panel, configured to be walked on, which provides the pedestrian with the sensation of walking on a traditional floor, and not on a photovoltaic panel.

Another object of the invention is to propose a photovoltaic panel, configured to be walked on, which provides the observer with the optical effect of a traditional floor, and not of a photovoltaic panel.

Another object of the invention is to propose a panel which presents a remarkable simplicity of installation.

Another object of the invention is to propose a panel which constitutes the optimal solution, in terms of simplicity of construction, for modifying the aesthetic aspect of a traditional photovoltaic panel.

Another object of the invention is to propose a panel with low aesthetic impact and/or which in any case can be easily integrated in an urban context, or in the context of the home or building, without in any way disfiguring the surrounding territory.

Another object of the invention is to propose a panel that can also be installed in areas where current legislation or regulations prohibit, for landscape, architectural or aesthetic reasons in general, the installation of panels.

Another object of the invention is to propose a panel that is highly customizable and aesthetically pleasing and suitable for providing the user with the feeling of being in front of a high quality product, both aesthetically and functionally. Another object of the invention is to propose a panel that can be safely stepped on even in rain and/or snow and/or ice conditions.

Another object of the invention is to propose a panel that can be used to define an illuminated path.

Another object of the invention is to propose a panel which is resistant and durable.

Another object of the invention is to propose a panel that can be either autonomous and independent from the national electricity grid (i.e. "off-grid") or connected to the electricity grid (i.e. "on-grid").

Another object of the invention is to propose a panel which can be mass- produced quickly and efficiently.

Another object of the invention is to propose a panel which presents an alternative characterization, both in construction and functional terms, with respect to the traditional ones.

Another object of the invention is to propose a panel which is visually different from the traditional ones, without changing the efficiency of the panel itself.

Another object of the invention is to propose a panel which is particularly compact and which integrates a large part or all of the elements necessary for its operation.

Another object of the invention is to propose a panel which results in high standards, both functional and aesthetic, thus allowing the possibility of its diffusion on a large scale.

All these purposes, whether considered alone or in any combination thereof, and others which will result from the following description are achieved, according to the invention, with an improved photovoltaic panel with the characteristics indicated in claim 1 and with a floor installation with the characteristics indicated in claim 24. The present invention is further clarified below in a preferred form of practical embodiment thereof, given by way of non-limiting example only, with reference to the attached drawings, in which:

Figure 1 shows in exploded perspective view of a photovoltaic panel according to the invention,

Figure 2 shows it in perspective view from behind,

Figure 3 shows it in section,

Figure 4 shows a front view of the internal surface of the rear sheet,

Figure 5 shows a front view of the photovoltaic cells applied on the back sheet of fig. 4,

Figure 6a shows a front view of a photovoltaic panel without coloring the internal surface of the rear sheet,

Figure 6b shows an enlarged detail of fig. 6a,

Figure 6c shows a front view of the panel of fig. 6a wherein the internal surface of the rear sheet has been suitably colored the same color as the photovoltaic cells,

Figure 7a shows a front view of a photovoltaic panel according to the invention in which the photovoltaic cells, the rear sheet and the upper/front sheet are been properly decorated,

Figure 7b shows a front view of a photovoltaic panel in which the photovoltaic cells, the back sheet and the upper/front sheet have been suitably decorated in a different way than in fig. 7a,

Figure 7c shows an enlarged detail of fig. 7b,

Figures 8 a-f show various textures of the upper/front sheet,

Figure 9 shows the panel in rear view with the laminar element of rear closure,

Figure 10 shows a top view of a floor installation according to the invention, Figure 1 1 shows a section of a first embodiment of the floor installation, Figure 12 shows it in a second embodiment, Figure 13 shows a perspective view of a detail of a floor installation according to the invention, and

Figure 14 shows a perspective view of an example of the floor installation according to the invention.

As can be seen from the figures, the photovoltaic panel 2 according to the invention is of the type intended to be installed horizontally, or inclined with respect to the horizontal, so as to define an outdoor floor or, in general, a coating of a surface of trampling.

Photovoltaic panel 2 includes:

- an assembly 10 comprising an array 3 of photovoltaic cells 4 interposed and laminated between two layers 8’ and 8" of encapsulating material,

- at least one upper/front sheet of transparent and/or translucent material 20 associated with the upper/front surface, intended to be visible, of said assembly 10,

- a rear/lower sheet 12 of electrically insulating material associated with the rear/lower surface of said assembly 10.

Preferably, the photovoltaic panel 2 has a substantially flat development.

Preferably, the panel substantially comprises sixty photovoltaic cells 4 having conversion efficiency of about 15-18%.

Suitably, the photovoltaic cells 4 can be made of silicon, and preferably of monocrystalline silicon. Alternatively, the photovoltaic cells 4 can be made of polycrystalline or amorphous silicon or CIGS (“Copper Indium Gallium Selenide” i.e. Indium Gallium Selenide and copper) or CIS (Copper Indium Selenide, i.e. Indium Selenide and copper). Alternatively, the cells 4 can be made from organic materials, for example from polymers (e.g. poly (3,4-ethylene dioxythiophene): poly (4-styrenesulfonate), PEDOT: PSS) or from molecules (e.g. phthalocyanines or fullerenes). Suitably, said photovoltaic cells 4 are blue and/or black in color of crystalline or amorphous silicon. Suitably, the photovoltaic cells 4 - and in particular their exposed surfaces - can be configured to be of a different color from the traditional blue and/or black, that is to reflect mainly the light of a certain color, which can be gray for example metallic, green, violet, golden, or brick red. Advantageously, the coloring of each cell 4 can be obtained by engineering the various layers which form the cell itself, as for example described in EP2154727.

Preferably, each cell 4 comprises an external anti-reflective layer which is generally made of S1O2, SiNx, optionally added with hydrogen or ZnS. Suitably, the cell 4 is configured so as to have a final efficiency of between 15 and 20%, and preferably between 16 and 19%.

The photovoltaic cells 4 of the array 3 are electrically connected to each other by connection bands 6, defined as ribbons, which are preferably made of copper covered with a tin alloy. Suitably, the connection bands 6 are provided frontally on the cells 4, however they could also be provided on the back of the cells themselves, as provided by the " back-contact " technology.

The array 3 of photovoltaic cells 4 is interposed between two layers of encapsulating material - respectively 8’ (the upper/front one) and 8" (the rear/lower one) - preferably EVA (ethylene-vinyl acetate).

Preferably, the photovoltaic panel 2 is of the laminated type. In particular, suitably, the array 3 of photovoltaic cells 4 interposed between the two layers of encapsulating material 8’ and 8", the upper/front sheet 20 and the rear/lower sheet 12 are subjected to a lamination process so as to join and glue the various sheets and layers to the array 3, thus creating a single and compact body. In more detail, this process is of the thermal type and provides that, through vacuum cooking (lamination), the two layers of encapsulating material 8’ and 8" are transformed into a gel which goes to incorporate the photovoltaic cells 4 and substantially to glue the upper/front 20 and rear/lower sheets 12. Preferably the process can take place at about 140-150°C under vacuum in a suitable oven (laminator) so as to remove the air inside the panel.

The upper/front layer of encapsulating material 8’ is associated with at least one upper/front sheet 20 which is made of transparent and/or translucent material of a structural type and suitable for being walked on (i.e. suitable for withstanding the passage of a plurality of subjects without getting damaged). In particular, in the panel 2 according to the invention, only said upper/front sheet is made of a material of a structural type and suitable for being walked on, so as to carry out substantially the structural functions of the panel itself. In essence, said upper/front sheet of panel 2 is the only structural element/component of the panel itself.

Suitably, below, in line with the provisions of EEC Directive 89/106, "structural" material/component means a material/component that allows the work/product (i.e. panel 2) in which it is incorporated to satisfy the requirement for mechanical strength and stability, as well as the requirement for durability. In more detail, the requirement of mechanical strength and stability is satisfied if it allows to avoid the collapse of the work/product or part of it, inadmissible deformations and/or damages.

Conveniently, in other words, the upper/front sheet 20 can be configured to absorb substantially by itself the load/weight applied on the solar panel 2.

Preferably, the upper/front sheet 20 is made of structural glass. Conveniently, the upper/front sheet 20 has the function of protecting and guaranteeing strength, substantially alone, to the entire photovoltaic panel 2 while maintaining high transparency.

Preferably, the upper/front sheet 20 is preferably made of prismatic solar glass with high light transmittance, so as not to substantially reduce the efficiency of the photovoltaic panel 2.

Preferably, the upper/front sheet 20 is made of a single piece/sheet of structural glass. Preferably, the upper/front sheet 20 is tempered.

Advantageously, the upper/front sheet 20 has a thickness of at least 2- 10 mm, and preferably of at least about 8-10 mm to guarantee the appropriate structural properties. Preferably, the upper/front sheet 20 can have a thickness of about 10 mm. Preferably, the upper/front sheet 20 can have a thickness greater than about 10 mm.

Advantageously, the upper/front sheet 20 is configured to support a load equal to or greater than about 2000 N/m ² , preferably of at least about 7000 N/m ² .

Advantageously, the upper/front sheet 20 can have a weight of about

20kg/m ² - 25kg/m ² .

Advantageously, in a possible embodiment (not shown), said panel 2 can comprise a further upper/front sheet (not shown), which is positioned above said upper/front sheet 20, in order to improve stability and the mechanical strength of the panel 2. Advantageously, said further upper/front sheet can be laminated together with the other layers or mechanically fixed to the other layers. Advantageously, said upper/front sheet 20 and said further upper/front sheet can be joined mechanically or by interposing a layer of encapsulating material which can be the same or different than that used for the layers 8, 8’.

Advantageously, the capturing surface (which is suitably defined by the external face 29) of the upper/front sheet 20 can be treated with a nanotechnological process which gives the surface itself the property of concentrating dirt or powder, without limiting the yield of the panel 2 and promoting periodic cleaning of the same.

Preferably, the external face 29 of the upper/front sheet 20 can be treated in such a way as to make it super hydrophobic, so as to avoid the accumulation of water, and allow it to slide outside the surface of the glass itself, also allowing to remove any dirt and/or powder from the glass surface. Suitably, these treatments can be carried out chemically, by depositing a super hydrophobic layer by spray coating or by chemical vapor deposition (in English "Chemical Vapor Deposition"), or they can be carried out physically, for example by means of nano-structuring the surface.

Advantageously, moreover, the external face 29 of the upper/front sheet 20 can be treated with non-slip treatments and/or can include a suitable texture

60. Conveniently, said texture is defined by a plurality of reliefs and/or incisions which are obtained, preferably chemically and permanently, on the external face 29 of said sheet.

Suitably, the textures 60 can be defined on the basis of the anti-slip and/or transparency characteristics required of the sheet itself. In particular, one or more of the following textures can be defined on the external face 29 of the upper/front sheet 20:

- a texture consisting of small ovals (see fig. 8a),

- a texture consisting of meso-pores with a substantially random arrangement obtained for example by means of controlled chemical etching, which make it possible to roughen and/or render opaque the entire structure of the glass front sheet 20 (see fig. 8b),

- a circular grid texture in relief (see fig. 8c),

- a texture made up of raised lines spaced and parallel to each other (see fig.

8d); suitably, the lines can be parallel to one of the two sides of the panel 2 or have an appropriate angle with the latter,

- a texture consisting of a matrix of squares in slight protrusion (see fig. 8e),

- a texture consisting of circular points in relief and arranged in a cross (see fig. 8f);

Advantageously, the texture can be configured to define a decoration, a writing, an image or any other ornamental motif.

Preferably, the raised tops of said textures 60 are opaque and roughened, while the background is bright. Suitably, the different textures 60 allow to obtain different anti-slip levels, preferably higher than 0.4 according to the BCRA-Tortus (British Ceramic Research Association) method which measures the dynamic friction coefficient between the sample to be tested and a sliding element at constant speed.

Advantageously, the non-slip effect of the external face 29 of the upper/front sheet 20 - measured according to DIN 51 130 with the ramp method - has a value greater than 9 and preferably is greater than 1 1 , and more preferably 13, corresponding to a instability angle greater than 6°, 19° and 35°. Suitably, this allows to walk on it even in wet conditions.

Suitably, the external face 29 of the upper/front sheet 20 can have a slip resistance greater than 0.42, according to the AINSI A 137-1 : 2012 standard and using the criteria for tiles that can be walked on with hard materials.

Advantageously, the upper/front sheet 20 of the photovoltaic panel 2 can have at least one decoration 24 which can be a writing, an image, a coloring and/or a color coupling, etc. Conveniently, the decoration is obtained with any glass processing technique, such as laser engraving, screen printing, sandblasting, etc. Alternatively, the decoration 24 can be made by painting, or printing, preferably with fluorescent inks capable of absorbing ultraviolet radiation, so as to absorb less visible light, and therefore allow greater efficiency of the solar panel 2, or even for enamelling, or with other methods.

In particular, the sheet 20 in transparent and/or translucent material, which is made of structural material and suitable for being walked on, includes decorations 24 which are obtained by at least a processing carried out directly on the surface of said sheet 20 and/or inside the thickness of said sheet 20.

Preferably, the upper/front sheet 20 can be suitably worked and/or treated according to what is provided in WO2018025249, the content of which is intended herein to be incorporated entirely by reference. Advantageously, a further sheet, or even more additional sheets, of particularly reduced thickness and of identical or different color with respect to the underlying glass sheet, can also be placed on the upper/front sheet 20.

Conveniently, above the upper/front layer of encapsulating material 8', a multilayer consisting of a plurality of sheets 20, superimposed on each other, in transparent and/or translucent structural material suitable for being walked on can be positioned.

Conveniently, above the upper/front sheet 20, an additional sheet in electrochromic material can be positioned and, preferably, it can use the energy generated by the solar panel 2 to be put in and/or kept in operation. For example, said additional sheet in electrochromic material can pass between an opaque and colored configuration (for example of an opaque white color) in which the photovoltaic cell array 3 is, at least partially obscured, and a transparent configuration in which the photovoltaic cell array 3 is, at least partially, capable of receiving electromagnetic radiation from the outside.

In an embodiment not shown, a film comprising a plurality of light sources (preferably LEDs) can be associated with the upper/front sheet 20, and in particular with its external and/or internal surface, which for example can be used to compose a static or moving image (i.e. a movie). Basically, in this way it is possible to transform the photovoltaic panel 2 into a monitor.

Additionally, a rear/lower sheet 12 is associated with the rear layer of encapsulating material 8” which can be made of transparent and/or translucent material, or can be made of opaque material.

Suitably, the rear sheet 12 can be made of a material which is not structural, i.e. not suitable for supporting high mechanical stresses and/or is not suitable for withstanding the passage of a plurality of subjects without being damaged, such as for example polymeric materials, such as example EVA, or PMMA. Substantially, therefore, the rear sheet 12 has no structural function and, in particular, it is not a structural component of the panel itself. In other words, the load/weight possibly exerted on the panel 2 can be supported/absorbed substantially exclusively by the upper/front sheet 20.

Conveniently, the rear/lower sheet 12 is made of a material, preferably plastic, which has the function of insulating electrically, protect and shield the array 3 of photovoltaic cells 4 from external agents (rain and humidity). Preferably, the rear/lower sheet 12 is made of a polyester-based laminate which guarantees high sealing of the photovoltaic panel itself, constituting a barrier in particular against oxygen and humidity.

Conveniently, the rear/lower sheet 12 can comprise colored or decorated portions 28 (see fig. 4) obtained in correspondence with its internal surface 27, i.e. that destined to face the rear layer 8” of encapsulating material.

Preferably, for this purpose, the internal surface 27 of the rear sheet 12 is colored, at least partially, so as to make it substantially of the same color as the photovoltaic cells 4 or of another desired color. Suitably, the entire internal surface 27 of the rear sheet 12 can be colored. Conveniently, the internal surface 27 of the rear/lower sheet 12 is colored and/or decorated in such a way as to present a specific ornamental motif, for example with drawings, images, writings, shapes and/or other elements, preferably recurrent and serial.

Suitably, the colored or decorated portions 28 of the internal surface 27 of the rear sheet 12 are obtained by painting, printing, or by other methods.

Advantageously, the colored or decorated portions 28 of the rear/lower sheet 12 are positioned and configured in such a way as to define a homogeneous background color at least, and preferably only, in correspondence with the spaces present between the photovoltaic cells 4 of the array 3 and/or of the spaces between the perimeter cells and the edges of the panel. Preferably, the colored or decorated portions 28 of the rear/lower sheet 12 are positioned and configured only in correspondence with the spaces present between the photovoltaic cells 4 of the array 3 and/or the spaces present between the perimeter cells and the edges of the panel. In particular, for this purpose, the colored or decorated portions comprise colored sections or strips 28 obtained on the internal surface 27 of the rear sheet 12 and of a color substantially corresponding to that of the photovoltaic cells 4 or of another desired color (see fig. 4 and 5).

Conveniently, the colored strips 28 are defined on the internal surface

27 of the rear sheet 12 in a manner substantially corresponding, from a dimensional, shape and position point of view, to the spaces that are provided between the photovoltaic cells 4 and/or the spaces present between the cells and the edges of the panel. In other words, the colored stripes 28 are defined in correspondence with the areas of the internal surface 27 of the rear sheet 12 which are not covered by the photovoltaic cells 4 and which are crossed at the top by the connection bands 6 between the various photovoltaic cells 4. Advantageously, in this way, by covering the background spaces between the photovoltaic cells 4 by means of colored or decorated portions 28 of the rear sheet 12 having the same color as the said cells, the overall effect of a full and homogeneous base of a single color is obtained on the panel 2 (i.e. that of the cells), as shown for example in Figure 6c.

Preferably, in particular in the case of front connection bands 6 between the photovoltaic cells 4, said bands can be suitably treated, that is, they are darkened, so as to make them substantially the same color as the cells 4 or another desired color; in essence, this allows to have a homogeneous colored background for the decoration 24 of the front glass sheet 20. Preferably, this treatment is carried out by applying a suitable paint directly on the connection bands 6 between the photovoltaic cells 4.

Alternatively and/or in addition to the above, the decorations 24 of the front glass sheet 20 are positioned and configured in such a way as to cover and/or obscure the connection bands 6 between the photovoltaic cells 4. In particular, for this purpose, the decorations 24 comprise colored and/or decorated sections/strips obtained on the front glass sheet 20 and of a color substantially corresponding to that of the photovoltaic cells 4 or another desired color. Suitably, the colored strips are defined on the front sheet 20 in a way substantially corresponding, from a dimensional, shape and position point of view, to the connection bands 6 between the photovoltaic cells 4. Basically, covering the connection bands 6 by decorations 24 of the front glass sheet 20 having the same color as the cells 4, the overall effect of a full and homogeneous base of a single color (i.e. that of the cells) is obtained on the panel 2.

Advantageously, the decorations 24 of the front glass sheet 20 are positioned and configured in such a way as to also cover and/or obscure the scratches which are present on each photovoltaic cell 4 and which substantially correspond to the spaces present between the modules that make up each cell and they can comprise the electrical contacts between the different modules defining each photovoltaic cell 4. In particular, for this purpose, the decorations 24 comprise colored strips obtained on the front glass sheet 20 so as to cover the grooves of the photovoltaic cells 4 and, suitably, they are of a color substantially corresponding to that of the modules defining each photovoltaic cell 4, or of another desired color.

In this way it is possible to create panels 2 with high and highly customizable aesthetic standards, thus allowing the use even in situations/contexts in which traditional panels could not be used, such as historical centers, or other areas of landscape interest.

Advantageously, the panel 2 comprises an energy storage unit 13, which is preferably mounted on and/or housed in the panel itself, and which can be connected to the electrical network and/or to the array 3 of photovoltaic cells 4.

Advantageously to the rear sheet 12, which constitutes the back of the photovoltaic panel 2, can be associated with a box-like body 14, preferably a single box-like body 14, for containing the means for controlling and managing the panel itself.

Conveniently, the panel can comprise said energy storage unit 13, configured to store, at least partially, the electrical energy produced by the panel.

Advantageously, the panel 2 can be provided with an electric cable 16 for the connection of the panel itself to the domestic and/or national electrical network and/or to at least one electrical appliance (for example a lamppost) so as to supply it with electricity generated by said array 3 of photovoltaic cells 4.

Conveniently, the panel 2 can operate on grid, that is, be connected to the national electricity grid and in this way the energy produced by the photovoltaic cells 4, and possibly stored in the storage unit 13, can be fed into the national electricity grid. Conveniently, in this case, the electrical equipment to be powered can be connected to the electrical network

Advantageously, the panel 2 can operate off grid, that is, be self- sufficient and isolated from the national electricity grid. Conveniently, in this case, the electrical equipment is powered by the energy that is produced by the array 3 of photovoltaic cells, directly and/or after being stored in the storage unit 13.

In particular, therefore, the electrical equipment to be used can be electrically connected directly with the array 3 of photovoltaic cells 4 so that it can be powered directly by the electricity generated by the latters. Preferably, all or part of the energy produced by the array 3 of photovoltaic cells can be stored at all inside the storage unit 13, which can then be electrically connected to the electrical equipment to be powered. Advantageously, in this way the electrical equipment can be powered directly by the energy generated by the array 3 of photovoltaic cells 4 when the latter are illuminated by sunlight (and therefore generate electricity), while it can be powered by the energy stored in the inside the storage unit 13 when the photovoltaic cells are not illuminated by sunlight (and therefore do not generate electricity).

Suitably, the box-like body 14 can be closed on all its sides, and preferably only the electric cable 16 comes out, provided at its end with an electric connector 18 for the connection of the panel 2 to the domestic and/or national electric network and/or at least one electrical appliance to be powered.

Alternatively, the panel 2 can be considered as completely self- sufficient (i.e. used in an "off-grid" configuration), and substantially use the energy generated by the photovoltaic cells 4 only to supply suitable lighting means (not shown) associated with the panel itself, as will be described below; suitably, in this case, the electric cable 16 may not be present.

Advantageously, if the panel 2 is connected to the electrical network, the control and command system of the photovoltaic panel itself, which can be contained in the box-like body 14, can comprise an inverter and/or a transformer (not shown) to provide an alternating current at the output of the panel itself, that is at the electric connector 18 of the electric cable 16.

Advantageously, said unit 13 for storing electricity, preferably constituted from at least one electric battery, can be associated with the rear sheet 12, which constitutes the back of the photovoltaic panel 2, and a regulator to control the charge/discharge of the electrical energy of the unit 13. Advantageously if the panel is self-sufficient, the electric energy storage unit 13 can be at least partially charged with the electricity generated by cells 4 during the periods in which the panel receives solar lighting, and then is consumed - at least partially - to power the electrical equipment.

Advantageously, the energy storage unit 13 and the charge controller, any inverter and/or transformer are all integrated and housed inside the photovoltaic panel 2. Preferably, the charge controller is housed in the inside of the box-like body 14. Advantageously, the photovoltaic panel 2 comprises an external frame 22. Conveniently, this frame 22 can be defined by the edge of the front sheet 20, or it can be defined by a profile which is supported or associated with said sheet 20 and which, advantageously, can be configured to hold together the various layers and/or sheets that make up the panel itself. Preferably, the frame 22 is made of metal or its alloys (for example aluminum) and also has the function of guaranteeing strength and defining a practical attachment for the photovoltaic panel 2.

Preferably, said frame 22 has an edge which is substantially flush with the external surface of the upper/front sheet 20 and this in order both to improve the insolation (and therefore reduce the perimeter shadow areas) and the aesthetic impact, and to avoid defining tripping steps for the subjects who pass through it walking over it.

Advantageously, the frame 22 can also have surface decorations, preferably obtained by etching. Preferably, the frame 22 has chamfered edges.

Furthermore, a rear closure element 35 can be associated to the frame 22 and/or to the rear/lower sheet 12, preferably made of metal or of the same material as the frame 22, if present. Preferably, said rear closure element 35 comprises a plurality of micro-holes to allow the passage of air, and thus prevent overheating of the panel itself. Conveniently, the rear closure element 35 can affect most or almost entirely the surface development of the rear/lower sheet 12 (see fig. 9).

Alternatively, the frame 22 may not be present, since the upper/front sheet 20 can be sufficiently resistant to maintain the structural integrity of the panel 2.

Preferably the cables connecting the apparatus can be passed inside the frame 22 connection to the energy storage unit 13. Advantageously, supports can be attached to the frame 22 or to the rear/lower sheet 12 to fix the panel to the ground or to an underlying structure/surface.

Advantageously, according to the invention, the panel 2 consists exclusively of the assembly 10, the upper/front sheet 20 and the rear sheet 12 in electrically insulating material, that is, without providing for the presence of further layers, films or coatings.

Advantageously, the overall dimensions of the panel 2 in plan are defined by the dimensions of the array 3 of photovoltaic cells 4. Preferably, the panel 2, and in particular the upper/front sheet 20, has dimensions in length and width corresponding to those of the array 3 of photovoltaic cells 4.

The panel 2 according to the invention can comprise lighting means which, preferably, can be associated with at least one edge of said panel 2 to illuminate the upper/front sheet 20 and/or the areas around the perimeter of the panel itself. Suitably, the lighting means are associated with the edges of the panel 2, i.e. the edges of the upper/front sheet 20 and/or of the back sheet 12, and therefore are not incorporated within the layers 8 of encapsulating material.

Preferably, lighting means, preferably LED strips, can be associated with a part or the whole frame 22. In particular, the LED strips can be associated with the frame 22 along a single side, along two sides, preferably opposite to each other, or along all its four sides, both for the entire length of the sides or even for a single one part of these.

Suitably, the lighting means can be associated with the frame 22 so as to illuminate the decoration 24 of the upper/front sheet 20. In particular, for this purpose, the lighting means can be arranged and oriented so as to illuminate the front portion (i.e. view) and inside the panel itself.

Suitably, the lighting means can be associated with the frame 22 so as to illuminate the rear face of the panel and/or the external areas around the frame itself. Preferably, the lighting means can be configured and arranged so as to generate a diffused light, which expands outwards, in correspondence with the rear face of the panel.

Advantageously, the lighting means are electrically connected with the storage unit 13 so that they can be powered by the electricity stored in the latter. Advantageously, the lighting means are electrically connected directly with the array 3 of photovoltaic cells 4 so that they can be powered directly by the electrical energy generated by them. Suitably, said lighting means can be connected to the electric connector 18 to allow its power supply by means of the network electricity.

The panel according to the invention can be installed and used individually, but it could also be suitably connected and combined with other panels according to the invention. In the latter case, the individual photovoltaic panels 2 according to the invention can be suitably brought together so as to define a floor installation 50 for outdoor environments. Preferably, the floor installation 50 can define for example a walkable path.

Conveniently, the adjacent photovoltaic panels 2 can be positioned above a supporting structure 52, of a superelevation and support, which is supported on an underlying ground 55 (or on another underlying structure/surface). Suitably, said supporting structure 52 is configured to support the photovoltaic panels 2 spaced from the ground below, thus creating a cavity 54 between the panels 2 and the ground for the passage of air. Preferably, the panels 2 are placed side by side and supported so as to define a floating or raised floor. Preferably, the panels 2 are removably mounted on said supporting structure 52.

Preferably, the floor installation 50, comprising a plurality of panels 2 suitably placed side by side, can be used to define a walkway which, advantageously during the night or in conditions of low illumination, it can be illuminated by the lighting means present on one or more panels 2 of said structure. Conveniently, the box-like bodies 14 of one or more of the overlying photovoltaic panels 2 and/or the other components contained in said body can be housed inside the cavity 54 obtained by means of the supporting structure 52 which separates the panels 2 from the ground 55 below box-like, such as the energy storage unit 13, the control and command system of the photovoltaic panel 2, the charge regulator, the electric cable 16 and/or the electric connector 18.

Advantageously, the individual photovoltaic panels 2 according to the invention they can be suitably combined so that the combination of the decorations 24 and/or the lighting means of each panel 2 defines a single overall aesthetic effect of the floor installation 50.

Preferably, said supporting structure 52 can comprise and/or be constituted only by a plurality/assembly of support elements 53, which preferably are separate and independent from each other. Conveniently, said support elements 53 are positioned so as to support at least one photovoltaic panel 2, preferably two, three or four photovoltaic panels 2 having substantially rectangular surface development. Conveniently, said support elements 53 support, in an elevated position with respect to the ground below, at least one photovoltaic panel. Conveniently, each photovoltaic panel rests at its corners (and preferably at all its angles) and/or at an internal area on corresponding support elements 53.

Conveniently, the support elements 53 are distinct and separate elements with respect to the panels 2, and are removably associated/associable with each other for support and/or mechanical fixing, in particular for interlocking. Advantageously, the photovoltaic panels 2 can rest directly on said support elements 53. In particular, the lower rear sheet 12 of each panel 2 can rest directly on said support elements 53.

Advantageously, said supporting structure 52 is configured to support at least two photovoltaic panels 2, adjacent to each other and side by side, so that they are laterally spaced (i.e. not in contact) and so that the respective edges delimit an opening 59 communicating with the underlying cavity 54 defined between the panels 2 and the ground 55. Advantageously this allows a better air exchange inside the cavity 54, thus ensuring optimal ventilation of the photovoltaic panels, and in particular of the relative electronics, thus avoiding overheating problems. In particular, advantageously, the cavity 54 can extend substantially continuously, between the various support elements 53, below the whole structure 50.

Advantageously, the support elements 53 can comprise one or more appendages 56, preferably of laminar development, for positioning and/or lateral spacing of the photovoltaic panels 2. In particular, said appendages 56 act as lateral containment sides. Conveniently, each panel can be embedded between the appendages 56 of several support elements 53 which support the panel, or it can be positioned between the appendages 56 so as to leave a minimum play.

Preferably, said support elements 53 can be adjustable in height.

Preferably, said supporting structure 52 can comprise support elements 53 and a frame and/or a bracket for mounting the photovoltaic panels 2.

Conveniently, moreover, in the case of multiple photovoltaic panels 2, these can be electrically connected to each other so as to share the same storage unit 13 for electricity and/or so as to be associated with the same control and command system.

Advantageously, at least two photovoltaic panels 2 that make up the floor installation 50 can be electronically connected to each other and, preferably, so as to share the same command and control unit which allows their management in a synchronized manner. Suitably, said command and control unit can be mounted on board of one of said at least two panels 2, or it can be physically separated from these although electronically connected. Advantageously, said command and control unit can comprise an electronics configured (at software and/or hardware level) to implement an MPPT (i.e. " Maximum Power Point Tracker ") type control, which allows to extract the maximum power from the photovoltaic panels 2, and this also on the basis of the shadows that can be projected by any clouds, or by the passage of a user who walks above the structure itself. Advantageously, the calculation for implementing the MPPT type control can be carried out in real time. Suitably, said calculation for implementing the MPPT type control can be carried out for pairs of photovoltaic panels 2. Preferably, said electronics is configured so that, when a decrease in the electrical energy produced by at least one panel is detected (preferably by a pair of panels) of the floor installation, and this, for example against the shadow caused by the passage and/or the presence of a subject (or other element) which causes a decrease in the sunlight incident on the array 3 of photovoltaic cells 4, then it commands the other panels of the installation, which are connected to each other, to operate according to an MPPT control strategy.

The operation of the photovoltaic panel 2 according to the invention is clear from what has been described. In particular, the array 3 of photovoltaic cells 4 transforms, by means of a photovoltaic effect, the incident solar light into direct current which is then stored in the storage unit 13 via the charge controller or is sent directly to the inverter which transforms into alternating current for immediate self-consumption by a user external to the panel itself.

Advantageously, the electrical energy generated in the panel itself and stored in the storage unit 13 can be used to supply the associated lighting means and integrated in the panel itself. Advantageously, the electrical energy generated in the panel itself is used, without being stored in the storage unit 13, to directly supply the associated lighting means and integrated in the panel itself. Alternatively, at least a part of the electrical energy produced by the panel 2 can be fed into the network by means of the electric cable 16.

It is also understood that, in an alternative embodiment of the panel 2 according to the invention, this can be without means of connection to a user and that the electrical energy generated by the array 3 of photovoltaic cells 4, possibly stored in the storage unit 13, can only be used to power the lighting means provided in the panel itself. In particular, in this circumstance, the panel 2 has only an ornamental function and/or illumination of the environment or installation area, i.e. without any function of energy supply to the users.

From what has been said it is clear that the improved panel according to the invention is much more advantageous than the traditional ones in that:

- it allows a high aesthetic result since it can be suitably decorated and/or illuminated;

- has a highly pleasing aesthetic appearance even in the absence of natural lighting,

- has a prestigious aesthetic aspect, which allows it to be classified as a quality or luxury product,

- can be produced in an industrial way,

- allows the creation of an autonomous system ("on-grid" or "off-grid") for the supply of electricity; this is particularly useful for the supply of electricity to isolated users or in situations where it is difficult or impossible to connect to the electricity network being taken,

- it can be easily and quickly connected via its outlet to the domestic electricity network,

- it has excellent characteristics of ease of use and installation since it can be positioned both vertically and inclined,

- it is independent and compact since all its components are suitably integrated within the overall the same, - it requires a reduced installation space and it does not require external equipment, and

- it is flexible, modular and scalable as needed.

In particular, the panel according to the invention is particularly advantageous in that it can be used to define a floor installation or a covering suitable for being walked on, thus allowing to expand the possibilities and contexts for its installation.