WO2013136160A2

WO2013136160A2 - Photovoltaic panel

Info

Publication number: WO2013136160A2
Application number: PCT/IB2013/000377
Authority: WO
Inventors: Massimo Venturelli
Original assignee: Massimo Venturelli
Priority date: 2012-03-13
Filing date: 2013-03-13
Publication date: 2013-09-19
Also published as: ITMO20120063A1; WO2013136160A3

Abstract

A photovoltaic panel (1) comprising a frame (2) and a plurality of photovoltaic cells (3, 4) associated with the frame (2) and operatively connected to one another to convert the absorbed solar energy into electricity, each of the photovoltaic cells (3, 4) having a relative visible face turned to the outside, wherein the photovoltaic cells (3, 4) comprise one or more cells with a substantially parallelogram shape (3) and one or more cells with a substantially triangular shape (4).

Description

PHOTOVOLTAIC PANEL

Technical Field

The present invention relates to a photovoltaic panel.

Background Art

The photovoltaic panels known to date generally have a parallelogram shape and comprise a plurality of square- shaped cells connected together in series. The photovoltaic panels are today also widely used to cover roofs in order to exploit their large surfaces, which are constantly exposed to the sun and without other functional purposes besides that of covering, in order to obtain electricity. It follows therefore that the parallelogram shape of the photovoltaic panels does not allow precisely following the profile of the roofs and does not therefore permit covering their entire surface.

It therefore follows that the parallelogram-shaped photovoltaic panels do not allow fully exploiting the roofs on which they are fitted, thus considerably limiting the amount of energy that can be obtained. This limit of the parallelogram-shaped photovoltaic panels appears particularly evident in the case of prism-shaped roofs, i.e., having a plurality of adjacent and converging triangular faces, or in the case of roofs having one or more oblique sides.

For this reason, photovoltaic panels have also been developed having different shapes from those just mentioned.

In particular, the patent EP 2291863 describes a photovoltaic panel having a frame with a more or less triangular shape, in particular of the right-angled triangle type, where the vertexes connecting the sides to the hypotenuse are cut by means of straight lines. The triangular panels described by EP 2291863 comprise a plurality of square cells connected together in series.

This type of panels also has a number of drawbacks.

More in particular, the energy produced by these photovoltaic panels is considerably less than that which could be obtained by fully covering their available frame area.

This is due to the fact that the square cells that make it up do not manage to precisely reproduce the frame profile, inevitably leaving empty spaces between these and the frame itself. It follows therefore that this type of known panel is distinguished by low energy efficiency.

Description of the Invention

The main aim of the present invention is to provide a photovoltaic panel which allows to overcome the drawbacks of the state of the art.

Within this aim, one object of the present invention is to provide a photovoltaic panel which permits completely covering the surface of the roofs, by precisely following their profile, in particular in the cases of roofs having a triangular shape or oblique sides.

Another object of the present invention is to provide a photovoltaic panel which, besides having very flexible use, also has high energy efficiency.

Another object of the present invention is to provide a photovoltaic panel which allows to overcome the mentioned drawbacks of the state of the art in the ambit of a simple, rational, easy and effective to use as well as low cost solution.

The above objects are achieved by the present photovoltaic panel comprising a frame and a plurality of photovoltaic cells associated with said frame and operatively connected to one another to convert the absorbed solar energy into electricity, each of said photovoltaic cells having a relative visible face turned to the outside, characterized by the fact that said photovoltaic cells comprise one or more cells with a substantially parallelogram shape and one or more cells with a substantially triangular shape.

Brief Description of the Drawings

Other characteristics and advantages of the present invention will become more evident from the description of a preferred, but not sole, embodiment of a photovoltaic panel, illustrated purely as an example but not limited to the annexed drawings in which:

figure 1 is a top plan view of a photovoltaic panel according to the invention, in a first embodiment;

figure 2 is an enlargement of a detail of figure 1 ;

figure 3 is a top plan view of a photovoltaic panel according to the invention, in a second embodiment;

figure 4 is an enlargement of a detail of figure 3; figure 5 is an axonometric view of a photovoltaic panel according to the invention, in a third embodiment;

figure 6 is a top plan view of a covering made with the panels of figure 3.

Embodiments of the Invention

With particular reference to such figures, globally indicated by 1 is a photovoltaic panel according to the invention.

The panel 1 comprises a frame 2 and a plurality of photovoltaic cells 3, 4 associated with the frame 2 and electrically connected together to convert solar energy into electricity.

Advantageously, the frame 2 has a polygonal profile comprising a plurality of sides 2a, 2b, 2c of which at least one side 2c is oblique with respect to the others. More precisely, the frame 2 comprises at least two sides arranged substantially orthogonal to each other, identified in the illustrations by the reference numbers 2a and 2b, and at least one oblique side 2c with respect to the orthogonal sides 2a and 2b.

In the preferred embodiment shown in the figures 1 and 3, the frame 2 has a substantially right-angled triangle shape and, more in particular, an isosceles right-angled triangle. The orthogonal sides 2a and 2b and the oblique side 2c therefore correspond to the catheti and to the hypotenuse, respectively, of the frame 2 shaped this way.

Alternative embodiments cannot however be ruled out wherein the frame 2 is shaped like a right-angled trapezium or, as shown in the figure 5, wherein the frame 2 has four consecutive sides orthogonal to one another and one oblique side joining the two extremal sides of such orthogonal sides to define a closed profile.

The cells 3, 4 each have a relative visible face which is, during use, turned to the outside and therefore exposed to the rays of the sun. The cells 3, 4 can be of the single-crystalline or, preferably, of the poly-crystalline type.

According to the invention, the panel 1 comprises one or more cells with a substantially parallelogram shape 3 and one or more cells with a substantially triangular shape, identified in the illustrations by the reference number 4. By the term "substantially" used here is meant less the machining tolerances or slight shape variations which do not alter in any great way the geometry of the relative element. For example, the parallelogram cells 3 of the single-crystalline type have their respective vertexes rounded; in the same way, the triangular-shaped frame 2 can have two straight sections, of considerably smaller dimensions than those of the other sides, which connect the catheti of the frame itself to the hypotenuse.

Preferably, the panel 1 comprises a plurality of parallelogram cells 3 and a plurality of triangular cells 4 connected together electrically. More in detail, the triangular cells 4 are also shaped like a right-angled triangle and, preferably, like an isosceles right-angled triangle.

The catheti and the hypotenuse of the triangular cells 4 are identified in the illustrations by the reference numbers 4a, 4b and 4c, respectively.

Advantageously, the triangular cells 4 are arranged in correspondence to the oblique side 2c, i.e., to the hypotenuse of the frame 2 in the embodiment shown in the illustrations.

More in particular, the triangular cells 4 are arranged with their hypotenuse 4c substantially parallel to the oblique side 2c, i.e., to the hypotenuse of the frame 2 in the embodiment shown in the illustrations.

Preferably, all the triangular cells 4 are arranged adjacent to one another in correspondence to the oblique side 2c and in such a way that their hypotenuses 4c are substantially aligned with each other and parallel to the oblique side itself.

The triangular cells 4 are therefore arranged with their sides substantially parallel to the sides of the frame 2, i.e., with their catheti 4a and 4b parallel to the orthogonal sides 2a and 2b respectively, thus allowing the optimization of the available surface of the frame itself.

Suitably, the cells 3 and 4 are arranged along rows, identified in the illustrations with the reference number 5, which extend along a direction substantially parallel to one of the orthogonal sides 2a, 2b of the frame 2, in particular with the side identified in the illustrations by the number 2a. In the embodiments of the figures 1 and 3, the rows 5 therefore extend parallel to the cathetus 2a of the frame 2. The rows 5 are electrically connected in series to one another and each of them comprises at least one triangular cell 4.

More in detail, some of the rows 5 comprise one or more parallelogram cells 3 and, in such rows 5, the triangular cells 4 are arranged between the last parallelogram cell 3 (i.e., that arranged closer to the hypotenuse of the frame 2) and the oblique side 2c. The parallelogram cells 3 and the triangular cells 4 of each row 5 are therefore arranged aligned with each other in the direction of extension of the row itself. It therefore follows that the sides 3a of the parallelogram cells 3, substantially parallel to the direction of extension of the rows 5 are aligned with one another and one of such sides 3 a is also aligned with the cathetus 4a of the triangular cells 4 extending parallel to the row itself. Advantageously, the triangular cells 4- have the- same width as the parallelogram cells 3, i.e., their cathetus 4b, arranged orthogonal to the direction of extension of the rows 5, has the same length as the side 3 b of the parallelogram cells 3 which is also arranged orthogonal to the direction of extension of the rows 5. The attached illustrations show two alternative embodiments of the panel 1. In the first embodiment, shown in the figures 1 and 2, the parallelogram cells 3 have a substantially square shape and the area of their visible face is greater than the area of the visible face of the triangular cells 4. It therefore follows that the triangular cells 4 are able to generate and conduct an electrical current lower than that of the parallelogram cells 3.

In this first embodiment, the parallelogram cells 3 of each row 5 are connected in series to one another while the triangular cells 4 are connected in parallel to one or more of the other triangular cells 4 and are connected in series to the parallelogram cells 3 of the respective rows 5. More in particular, the number of triangular cells 4 connected in parallel the one to the other is a function of the area of their visible face, inasmuch as the electric current generated by the triangular cells 4 connected in parallel must be substantially the same as that of the parallelogram cells 3 connected in series to same.

In the embodiment shown in the figures 1 and 2, wherein the area of the visible faces of the triangular cells 4 corresponds to about half the area of the visible surfaces of the parallelogram cells 3, the triangular cells 4 are connected in parallel two by two.

Preferably, as shown in the illustrations, each row 5 comprises just one triangular cell 4 positioned in correspondence to the oblique side 2c of the frame 2. The triangular cells 4 of each row 5 are then connected in parallel to the triangular cell 4 of just one row 5 adjacent and in series with the parallelogram cells 3 of the relative rows 5.

The figure 2 shows in detail the reciprocal connections of the triangular cells 4 of the first two rows 5 of the panel 1 and the connections of same to the adjacent parallelogram cells 3. In particular, in figure 2, identified by the reference number 6 are the connections electrically connecting the negative electrodes of the triangular cells 4 (the illustrations show the "tracks" on the visible faces and suitable for collecting the negative electrical charges) to the positive electrode of the parallelogram cell 3 arranged downstream of same in the direction of current flow and, by the reference number 7, the connections electrically connecting the positive electrodes of the triangular cells 4 to each other (placed on their non-visible face) in turn connected to the negative electrode of the parallelogram cell 3 positioned upstream in the direction of current flow.

Both the connections 6 and the connections 7 are arranged on the non-visible face of the cells 3 and 4.

In the second embodiment shown in the figures 3 and 4, the parallelogram cells 3 have a substantially rectangular shape, where the cathetus 3a is about half as long as the cathetus 3b. In this second embodiment, therefore, the area of the visible face of the parallelogram cells 3 and that of the triangular cells 4 is substantially the same, and so the cells 3 and 4 are able to generate the same current.

In this second embodiment, the cells 3, 4 of each row 5 are connected together in series and are connected in series to the cells 3, 4 of the adjacent rows 5. Consequently, each cell 3, 4 is connected in series to the cells 3, 4 arranged upstream and downstream in the current flowing direction.

As in the case of the first embodiment therefore, the figure 4 shows, in detail, the reciprocal connections of the triangular cells 4 of two adjacent rows 5. In particular, in the figure 4, indicated by the reference number 8 are the connections that electrically connect the negative electrode of a triangular cell 4 to the positive electrode of the adjacent triangular cell 4.

For the technician in the sector, it is easy to appreciate that the connections shown in the figures 2 and 4 can be replaced with others arranged in a different but completely equivalent way from a functional viewpoint.

In a preferred but not sole embodiment, the catheti of the frame 2 have a length of around 133 cm, the distance of the cells 3 and 4 from the catheti of the frame 2 is around 2.5 cm and the distance of the hypotenuses of the triangular cells 4 from the hypotenuse of the frame 2 is around 2 cm. It therefore appears evident how the cells 3 and 4 making up the panel 1 substantially fully cover the area of the frame 2.

The figure 6 shows a photovoltaic system 10 comprising a plurality of photovoltaic panels with square base, identified in the illustration by the reference number 9, and a plurality of photovoltaic panels 1.

Suitably, the cells making up the panels 9 have the same dimensions and electrical characteristics (voltage, current and peak power) as the parallelogram cells of the panels 1. In particular, in the photovoltaic system 10 in figure 6, the panels 1 are of the type of the second embodiment described above, i.e., the relative parallelogram cells 3 have a rectangular shape and the area of their visible surface substantially corresponds to the area of the triangular cells 4. Preferably, the panels 9 comprise twice as many cells as the panels 1, in such a way that the generated current is substantially the same but the voltage of the panels 9 is substantially double that of the panels 1.

As can be clearly seen from such illustration, such photovoltaic system allows precisely covering a triangular-profile surface.

It has in fact been ascertained how the described invention achieves the proposed objects and in particular the fact is underlined that the photovoltaic panel according to the present invention, besides permitting the precise covering of the surfaces of roofs having oblique sides, has a high energy efficiency thanks to the use of triangular-shaped cells which permit fully exploiting the entire available surface of the panel itself. Furthermore, the device according to the invention allows making the rear wall of the panels in white colour, to reduce the heating temperatures of the panels themselves and consequently improve efficiency, without at the same time negatively affecting their aesthetic impact thanks to the complete coverage of the available surface.

Again, the device according to the invention permits connecting together identical strings in parallel, thus avoiding mismatching.

Claims

1) Photovoltaic panel (1) comprising a frame (2) and a plurality of photovoltaic cells (3, 4) associated with said frame (2) and operatively connected to one another to convert the absorbed solar energy into electricity, each of said photovoltaic cells (3, 4) having a relative visible face turned to the outside, characterized by the fact that said photovoltaic cells (3, 4) comprise one or more cells with a substantially parallelogram shape (3) and one or more cells with a substantially triangular shape (4).

2) Panel (1) according to claim 1, characterized by the fact that said frame has a plurality of sides of which at least an oblique side (2c) with respect to the others and that said triangular cells (4) are arranged in correspondence to said oblique side (2c).

3) Panel (1) according to claim 2, characterized by the fact that the hypotenuse of said triangular cells (4) is substantially parallel to said oblique side (2c). 4) Panel (1) according to one or more of the preceding claims, characterized by the fact that it comprises a plurality of said triangular cells (4) arranged adjacent to one another in correspondence to said oblique side (2c), the hypotenuses of said triangular cells (4) being substantially aligned together and parallel to said oblique side (2c).

5) Panel (1) according to one or more of the preceding claims, characterized by the fact that said frame (2) comprises at least two sides arranged substantially orthogonal (2a, 2b) to one another and that said triangular cells (4) are shaped like a right-angled triangle, said triangular cells (4) being arranged with their hypotenuses (4c) and their catheti (4a, 4b) substantially parallel to said oblique side (2c) and to said orthogonal sides (2a, 2b) respectively, of said frame (2).

6) Panel (1) according to one or more of the preceding claims, characterized by the fact that it comprises a plurality of rows (5) of said photovoltaic cells (3, 4) which extend along a direction substantially parallel to at least one of said orthogonal sides (2a, 2b), wherein said rows (5) are connected to one another in series and wherein each of them comprises at least one of said triangular cells (4)·

7) Panel (1) according to one or more of the preceding claims, characterized by the fact that at least one of said rows (5) comprises at least one of said parallelogram cells (3) and that said triangular cells (4) are placed between the parallelogram cell (3) closer to said oblique side (2c) and the oblique side itself.

8) Panel (1) according to claim 7, characterized by the fact that each parallelogram cell (3) arranged along one of said rows (5) has a side (3a) substantially parallel to the direction of extension of the row itself and substantially aligned with one side (4a) of at least a triangular cell (4) belonging to the same row (5).

9) Panel (1) according to one or more of the preceding claims, characterized by the fact that the area of the visible face of said triangular cells (4) substantially corresponds to the area of the visible face of each of said parallelogram cells (3), said cells (3, 4) being connected together in series.

10) Panel (1) according to one or more of the claims from 1 to 8, characterized by the fact that the area of the visible face of said triangular cells (4) is smaller than the area of the visible face of each of said parallelogram cells (3), said parallelogram cells (3) being connected together in series and said triangular cells (4) being connected in parallel to at least another triangular cell (4) and in series to the parallelogram cells (3) arranged upstream and downstream to them in the current flowing direction.

1 1) Panel (1) according to claim 10, characterized by the fact that each of said rows (5) comprises just one triangular cell (4) and by the fact that each of said triangular cells is connected in parallel to the triangular cell of an adjacent row and in series to the parallelogram cells of the same row, the area of the visible face of said triangular cells corresponding substantially to half the area of the visible face of said parallelogram cells.

12) Panel (1) according to one or more of the preceding claims, characterized by the fact that said frame (2) has a substantially triangular shape, said orthogonal sides (2a, 2b) and said oblique side (2c) corresponding to the catheti and hypothenuse respectively of the frame itself, said triangular cells (4) being arranged with their hypothenuses (4c) substantially aligned together and parallel to said oblique side (2c) and with their catheti (4a, 4b) substantially parallel to the catheti (2a, 2b) of said frame (2).