A method and machine to assist recycling of photovoltaic panels

The present patent application for industrial invention relates to a method to assist recycling of photovoltaic panels and a machine for implementation of said method.

As it is known, photovoltaic panels (sometimes defined as photovoltaic modules) are obtained as a multi-layer panel comprising two external sides made of glass, for example tempered glass, inside which at least one layer of photovoltaic cells is contained and electrically connected with suitable electric connectors.

The presence of the external glass layer is required to provide a rigid support with low sensitivity to temperature change, on which photovoltaic cells are positioned and glued, being normally obtained with mutually interconnected silicon wafers.

The very large diffusion of photovoltaic panels requires the provision of a disposal method in order to recycle the various components. In fact, the glass of the external layer could be advantageously recycled with the known methods.

However, problems are encountered because of the configuration of panels: in order to be recycled, the glass must be separated from the internal silicon modules.

This operation is extremely difficult because of the adhesives (normally

EVA-based adhesives) used to fix the silicon modules to the glass, which make separation very difficult.

The object of the present invention is a method to assist the recycling of photovoltaic panels, which comprises a separation phase of the external glass layer from the layer of silicon photovoltaic modules that is at least partially obtained by crushing part of said glass layer in an operating area comprised between two opposite counter-rotating toothed rolls.

A further object of the present invention is a machine to assist recycling of photovoltaic panels, which comprises at least one pair of opposite counter-rotating toothed rolls, between which an operating area is defined, and a conveyor belt afferent to said operating area, to convey a photovoltaic panel to said operating area.

The glass of the external layers of the photovoltaic panels is crushed, separated from the underlying layer of silicon modules and collected in order to be advantageously recycled.

Ameliorative variants are also provided, wherein the number of pairs of toothed rolls is two, three or a higher number.

A particularly advantageous embodiment of the present invention comprises three pairs of opposite counter-rotating toothed rolls, wherein the height of the teeth of each pair of rolls decreases along the forward travel direction of the panel. In this way, the first rolls through which the photovoltaic panel passes, have teeth with highest height, and the last rolls have teeth with lowest height.

Advantageous characteristics are the object of the attached dependent claims.

For explanatory reasons, the description of the method and of the machine according to the present invention continues with reference to the attached drawings, which only have illustrative, not limiting value, wherein:

Figure 1 is a side view of a machine to assist the recycling of photovoltaic panels according to the present invention;

Figure 1 A is a side view of Fig. 1 ;

Figure 2 is a top view of the machine of Fig. 1 ;

Figure 3 is a side view of the machine of the preceding figures in working condition;

Figures 4, 5 and 6 are detailed views of the machine of the preceding figures.

Referring to Figs. 1 and 2, a machine (1 ) to assist the recycling of photovoltaic panels according to the present invention is disclosed.

According to the example, the machine (1 ) comprises a conveyor belt (2) and an optional loading arm (3) adapted to load a photovoltaic panel (not shown in Figs. 1 and 2) on the conveyor belt (2).

Said loading arm (3) supports a dish provided with suction caps (3a), which is physically responsible for taking one photovoltaic panel at a time from a basket (C) of panels and transferring it onto said conveyor belt (2).

In this example, said conveyor belt (2) is a roller conveyor belt, comprising a series of parallel rotating cylinders, but generally speaking it may also be of a different type, according to the specific requirements.

The conveyor belt (2) feeds the operating area of the machine (1 ) that is provided with three pairs of crushing rolls (4,5,6) in aligned configuration, as shown in detail in working condition in Fig. 4.

Obviously, it must be noted that any number of pairs of crushing rolls (4,5,6) can be used, it being necessary to provide at least one pair to realize the invention.

Going back to the figures, a particularly advantageous embodiment of the machine (1 ) provided with three pairs of rolls is disclosed.

Each pair of crushing rolls (4,5,6) comprises a first and a second opposite counter-rotating roll (4A,4B; 5A,5B;6A,6B) provided with parallel axes of rotation, which are spaced in such manner that teeth are never in mutual contact: an operating area is defined between the two rolls (4A,4B; 5A,5B;6A,6B) of each pair (4,5,6), through which the photovoltaic panel (PF) passes, as schematically shown in Fig. 4.

Moreover, the machine comprises adjustments means of the distance of said axes of rotation of the rolls (4A,4B; 5A,5B;6A,6B) of each pair (4,5,6), in such a way to determine the mutual approach and/or removal of said rolls, thus changing the space (L) as desired in correspondence of the operating area between two rolls of the same pair (4,5,6), in order to adjust it to the thickness (s) and characteristics of the photovoltaic panel (PF), it being evident that said thickness (s) must always be higher than said space (L) in order for the toothed rolls to bite and crush the glass layers of the photovoltaic panel (PF) .

Part of a pair of crushing rolls (viz. 4A and 4B) is shown in Fig. 5, wherein the teeth of the roll have a sharp edge and a V-notch between two consecutive teeth, in such a way to easily crushing the glass layer of the panel.

With reference to the teeth, the applicant has noted that, in case of a plurality of pairs of rolls (4,5,6) in aligned configuration, teeth (h) with different height between the various pairs of rolls (4,5,6) must be provided to guarantee the best crushing, separation and detachment of glass from the covering layer of the panel (PF).

More specifically, the applicant has noted that the optimal height of the teeth for the first pair (4) is approximately 4 mm, for the second pair (5) is approximately 2 mm and for the third pair (6) is approximately 1 mm.

The terms "first", "second" and "third" as used herein refer to the progressive forward travel of a photovoltaic panel (PF) in the machine: therefore, in the first example, the first pair (4) is the pair that is initially encountered by the panel (PF), whereas the third pair (6) is the pair that is encountered by the panel (PF) last.

As shown in Fig. 6, the third pair of rolls (6) is provided with teeth with height (hi ) and space (L1 ) lower than height (h) and space (L) of the first pair (4).

The pairs of rolls (4,5,6) are mounted on a frame (10) with basically portal-like shape in the present embodiment (it being empty in the lower portion), in such a way to provide the forward travel of the panel (PF) disposed with larger dimensions on a horizontal plane parallel to the axes of rotation of the rolls (4A,4B; 5A,5B;6A,6B).

According to additional embodiments, which are not shown herein, the axes of rotation of the rolls (4A,4B; 5A,5B;6A,6B) are disposed vertically and the panel (PF) travels forward with larger dimensions on a vertical plane.

Moreover, in other additional embodiments, the reference planes are inclined by any angle.

The machine (1 ) also comprises a collection conveyor belt (8), adapted to collect the glass scraps (SV) and disposed at least under every pair of rolls (4,5,6), as shown in the working condition of Fig. 3.

As shown in this example, the glass of the covering layers of the panel (PF) falls by gravity on the collection conveyor belt (8) and is conveyed towards a collection container (12), such as a basket, a tank, or the like, in order to be sent to a recycling operation.

In order to simplify the handling of said container (12), the container (12) is not provided under the pairs of rolls (4,5 and 6) and at the end of the conveyor belt (8), but in external lateral position to said frame (10), in such manner that a second conveyor belt (8a) is provided, being fed by the first conveyor belt (8) and oriented orthogonal to it.

The layer of photovoltaic cells with electric connections, deprived of the external glass layers, comes out of the last pair of rolls (6) and is collected by a collection basket (1 1 ) situated downstream the third and last pair (6) .

The operation of the machine (1 ) appears evident from the aforementioned description.

Specifically, a panel (PF) is fed by the loading arm (3) on the conveyor belt (2) and is taken to the operating area comprised between the two rolls

(4A,4B) of the first pair (4) of rolls.

The two rolls (4A,4B) are counter-rotating and therefore, as soon as the end of the panel (PF) is inserted in the operating area, the rolls (4A,4B) drag the entire panel (PF) into the operating area, where the teeth of the pair of rolls (4) make a first crushing and separation of the external glass layer of the panel (PF), thus removing approximately 25-30% of the glass.

Then, the panel (PF) is transferred by the first pair of rolls (4) to the operating area of the second pair of rolls (5): also in this case, the rolls (5A,5B) drag the entire panel (PF) into the operating area, thus causing a second crushing and separation of the external glass layer of the panel (PF) and removing approximately 70% of the glass.

Finally, the panel (PF) is transferred by the second pair of rolls (5) to the operating area of the third pair of rolls (6): also in this case, the rolls (6A,6B) drag the entire panel (PF) into the operating area, thus causing a third crushing and separation of the external glass layer of the panel (PF) and removing the remaining glass. In order to summarize the aforementioned description, generally speaking, the method to assist recycling of photovoltaic panels (PF) according to the present invention comprises a separation phase of the external glass layer from the layer of silicon photovoltaic modules of the panel (PF), wherein said separation phase is obtained at least partially by crushing part of said glass layer in an operating area comprised between two opposite counter-rotating toothed rolls (4A,4B; 5A,5B; 6A,6B) of a pair of rolls (4,5,6).

More specifically, the method comprises at least two, preferably three, separation phases obtained at least partially by crushing part of said glass layer in operating areas comprised between two opposite counter-rotating toothed rolls (4A, 4B; 5A, 5B; 6A, 6B) of corresponding pairs of rolls (4, 5, 6).

According to an advantageous characteristic, the method also provides for dragging said panel (PF) forward to said operating areas comprised between two rolls (4A, 4B; 5A, 5B; 6A, 6B), said operating areas being aligned and provided with spaces (L) with decreasing height along the forward travel direction of said panel (PF).

Obviously, operation is analogous in case of more than three pairs of rolls, thus omitting details.

Therefore, the aforementioned purposes are achieved.

Additional variants to the aforementioned description are possible and must be considered within the reach of an expert of the field in the light of the precepts provided herein.