DE S CRI PT ION

FIELD OF THE INVENTION

The present invention refers to the field of the energy production devices and, particularly, it refers to a method for producing electric energy by harnessing the solar energy by the photovoltaic effect with an amorphous silicon thin film directly embedded inside a plastic fabric (preferably ETFE, ethylene tetra fluoroethylene) of the windable curtain or covering.

More speci ically, the object of the present invention consists of providing a windable curtain comprising a plurality of flexible thin film modules made of amorphous silicon in a single, or double or triple bonding, embedded in a plastic material thin film, having a high corrosion resistance in a wide range of temperatures; by ultrasonic welding it is possible to associate the edges of the plastic material in order to obtain a wide area of a windable flexible photovoltaic material on a suitable rotating tube which acts as a sun-shading curtain.

Therefore, the advantage consists of obtaining a covering which is used both as a sun-shield and for harnessing the solar energy incident on the curtain for producing electric energy. Said objects and advantages are all met by the windable curtain having a photovoltaic circuit, object of the present invention, which is characterized in the following claims.

BRIEF DESCRIPTION OF THE FIGURES

This and other characteristics will be better understood from the following description of some embodiments shown in an illustrative non limiting way, in the attached drawings :

- Figure 1 shows a windable photovoltaic curtain on a supporting structure, in an unwinded condition;

- Figure 1A shows a thin amorphous silicon photovoltaic module, embedded between a thin film of plastic materials with side projecting protrusions for the association to adjacent modules;

- Figure 2 shows both the outline of the curtain with a driving motor and the cross-section of the winding tube of the curtain with photovoltaic panels;

- Figure 3 shows the connections of the positive and negative poles to the inverter;

- Figure 4 shows a module junction box;

- Figure 5 shows, as a whole, the rotating tube housing the positive terminals of the curtain;

- Figure 6 shows a detail of the end area of the tube;

- Figure 7 shows a detail of a cross-section view of the end area of the rotating tube.

DESCRIPTION OF THE INVENTION

As is it shown in Figures 1 and 1A, for manufacturing a windable curtain 1 having a double function: as a sun- shield/for producing electric energy by photovoltaic technology, it is used, as it will be explained in the following, a plurality of panels or modules, indicated at 2, of a thin flexible film of photovoltaic amorphous silicon, with a single, double and triple junctions. Said film 2 is embedded between a plastic material thin film, indicated at 3, in this particular case EPFE (ethylene tetra fluoroethylene) .

For example, a module or panel has the following dimensions: width 460 mm, length 3399 mm and other models, thickness: 1 mm, weight 1.57 kg and a power of 92 Wp. The final dimensions of the photovoltaic curtain, with reference to the type having 11 panels, are: width 5060 mm and length 3399 mm.

The whole peak power of the reference curtain is of 1012 and the efficiency is equal to or greater than 50 W/mq.

The curtain is formed by the abovementioned modules 2 assembled one to the other by drawing them close along their major sides: the plastic covering material 3, ETFE in this case, is wider than the photovoltaic module of about 2-2.5 cm per side.

It is pointed out that said silicon modules 2 are integrated in the plastic material fabric 3.

The bonding is made with a specific ultrasonic equipment which, by a sonotrode, bonds the two plastic edges 3 which melt in this way one into the other.

Indeed, during the welding, the melt portion of ^' the plastic material is pressed for obtaining the welding of the two panels.

The bonded modules or panels form a sheet acting as a windable curtain when the modules are fixed to a suitable supporting structure.

On the inside, the structure is provided with an electric motor for winding and extending the curtain. Each module, or strip, of silicon is provided, at the ends, with two corresponding junction boxes, one for the positive pole and the other for the negative pole; the junction boxes are housed inside the curtain supporting structure.

Specifically, the positive pole of the modules/panels faces the supporting structure ("inner" portion) and can disappear inside a corresponding rotating tube, while the negative pole faces the "outer" portion of the photovoltaic curtain.

The assembled modules are parallelly connected; the cable connecting the positive poles (inner portion) is integral with the opening and closing movements of the curtain, in order to avoid tears and failures of the cable itself; the other side of the cable is instead fixed to the "outer" portion of the stationary structure, then it is connected to an outer inverter. Another illustrative connection variant of a model different from the one used as an example, consists of two positive and negative poles which exit from the same side of the photovoltaic curtain to be parallelly or serially connected.

A rotating connector, always in contact, enables to wind the curtain (because its positive cable moves/rotates upon each opening/closure) and its connection to the cable of the outer inverter, which is always stationary or in an helicoidal gathering system which automatically unwinds or winds the cable by allowing the output outer connector to remain stationary.

The negative pole is located, as said before, in the "outer" portion of the curtain; the cable having a negative polarity is taken towards the upper portion of the curtain, by following the path of the support arms of the curtain, by a suitable cable.

The inverters are of the 1 k and 2 kW type, for matching the characteristics of the thin film panel and the different dimensions of the curtain.

It is moreover provided a decoupling transformer for eliminating the eddy currents generated by the use of the amorphous thin film.