DESCRIPTION The present invention concerns a device for soldering the interconnections of photovoltaic panels.

The invention is applicable in the industrial field, in particular in the sector of the production of photovoltaic panels.

Photovoltaic panels generally comprise a plurality of cells (usually sixty or seventy-two), which are connected to each other through the use of first ribbon filaments, constituting bus bars, which are in turn soldered to second ribbon filaments, called “header” ribbons, orthogonal to the former and usually wider than them.

To connect the bus bars to the header ribbons, a soldering is normally carried out between them, melting the tin that covers the header ribbon after positioning the latter on the ribbons of the bus bar.

Usually, the soldering is carried out using numerical control equipment equipped with induction or laser soldering devices, which carry out a punctual soldering by melting the header ribbon in correspondence with each single bus bar ribbon, creating the joint once solidification has occurred.

The state of the art has some disadvantages.

Normally, the device for such solders has:

- either a terminal with a single induction point that moves along the header ribbon, between the successive bus bars, with a pitch corresponding to the distance between them; however, this determines a long and uncomfortable production method and the need to reprogram the pitch in the event of a variation in panel format and therefore in the distance between the bus bars,

- or a terminal with a plurality of induction points, generally between five and ten, positioned at a distance corresponding to the distance between the bus bars, which moves step-wise between successive groups of bus bars; however, this determines the need to replace the terminal in the event of a variation in the format of the panel to be made, and therefore in the distance between the bus bars, with a consequent reduction in production due to the downtimes necessary for the replacement of the terminal and the reprogramming of the equipment,

- or a terminal equipped with a laser source directed toward the point of intersection between the header ribbon and a bus bar ribbon, which moves along the header ribbon, between the successive bus bars, with a pitch corresponding to the distance between them; however, this determines a long and uncomfortable production method and the need to reprogram the pitch in the event of a variation in the panel format and therefore in the distance between the bus bars.

The aim of the present invention is to provide a device for soldering the interconnections of photovoltaic panels which is able to improve the state of the art in one or more of the aspects indicated above.

Within this aim, one purpose of the invention is to provide a device for soldering the interconnections of photovoltaic panels which can be used for any format of photovoltaic panel whatsoever, and which allows soldering for any format of photovoltaic panel whatsoever, regardless of the distance between the bus bars.

Another purpose of the invention is to provide a device for soldering the interconnections of photovoltaic panels which does not require the need to replace the terminal in the event of a variation in the format of the panel to be made, simultaneously increasing the productivity of the equipment with which it is associated, given the same time, compared to similar devices of a known type.

Furthermore, the present invention aims to overcome the disadvantages of the state of the art in an alternative way to possible existing solutions.

Not the last purpose of the invention is to provide a device for soldering the interconnections of photovoltaic panels which is highly reliable, relatively easy to manufacture and at competitive costs.

This task, as well as these and other purposes that will be clearer below, are achieved by a device for soldering the interconnections of photovoltaic panels, characterized in that it comprises:

- an inductor, which in turn comprises a filament, which substantially develops so as to form two parallel branches: a first branch and a second branch,

- an insert, which has a longitudinal development, which is at least partly surrounded longitudinally by the filament and is interposed between the two branches. Other characteristics and advantages of the invention will become more apparent from the description of a preferred but not exclusive embodiment of the device for soldering the interconnections of photovoltaic panels according to the invention, which is shown, by way of a non-limiting example, in the attached drawings, wherein:

- figs la and lb each show a different view of a device for soldering the interconnections of photovoltaic panels according to the invention;

- fig. 2 shows an exploded view of the device of figs la and lb;

- fig. 3 shows an enlarged portion of the device of fig. la; - fig. 4 shows the internal components of the device for soldering the interconnections of photovoltaic panels according to the invention;

- fig. 5 shows a perspective view of an application of use of the device for soldering the interconnections of photovoltaic panels according to the invention.

With reference to the drawings above, a device for soldering the interconnections of photovoltaic panels, according to the invention, is indicated as a whole with reference number 10.

With particular reference to fig. 5, the device 10 operates on a photovoltaic panel 1, heating the header ribbon 2.

Advantageously, the soldering equipment comprises a plurality of aligned devices 10.

The device 10 comprises:

- an inductor 11, which in turn comprises a filament 12, which substantially develops so as to form two parallel branches 13a, 13b: a first branch 13a and a second branch 13b, - an insert 14, which has a longitudinal development, which is at least partly surrounded longitudinally by the filament 12 and is interposed between the two branches 13 a, 13b of the latter.

In practice, the filament 12 almost completely surrounds the insert 14 in its longitudinal direction, on a plane parallel to the lying plane of the photovoltaic panel 1.

In particular, the insert 14 is made of glass-ceramics material, preferably the one known by the trade name of “Macor” of the US company Coming Inc.

The inductor 11 develops from a heating head 15 of a per se known type. The inductor 11 comprises a pair of electrodes 16a, 16b.

Each branch 13a, 13b of the filament 12 develops starting from a respective one of the electrodes 16a, 16b toward a U-shaped reciprocal connection portion 17.

In particular, each branch 13a, 13b of the filament 12 comprises between the respective electrode 16a, 16b and the connection portion 17, in the following order:

- an arc-like segment 18a, 18b, for connection to the electrode 16a, 16b,

- a first substantially rectilinear segment 19a, 19b,

- a substantially U-shaped curvilinear segment 20a, 20b,

- a second substantially rectilinear segment 21a, 21b, parallel to the first substantially rectilinear segment 19a, 19b.

The lying plane of the first branch 13a of the filament 12 is parallel to the lying plane of the second branch 13b of the filament 12.

Specifically, the second substantially rectilinear segment 21a, 21b is parallel to the first substantially rectilinear segment 19a, 19b, but has a greater extension than it.

Furthermore:

- the second substantially rectilinear segment 21a of the first branch 13a is parallel to the second substantially rectilinear segment 21b of the second branch 13b,

- the first substantially rectilinear segment 19a of the first branch 13a is parallel to the first substantially rectilinear segment 19b of the second branch 13b.

The filament 12 is advantageously made of copper and has a tubular section with a square contour for the flow of cooling water.

The electrodes 16a, 16b have a substantially triangular profile and are symmetrical with respect to the plane of symmetry of the device 10 that is parallel to the lying plane of a branch 13a, 13b of the filament 12.

Each electrode 16a, 16b has a duct 22a, 22b for the flow of cooling water, which is in fluidic connection with the respective branch 13a, 13b of the filament 12.

The device 10 comprises a support 23 of the insert 14, which has a longitudinal development and an extension that is substantially equal to the extension of the latter and of the second substantially rectilinear segment 21a, 21b of the branches 13a, 13b of the filament 12.

The support 23 is interposed between the first substantially rectilinear segment 19a, 19b and the second substantially rectilinear segment 21a, 21b of the branches 13a, 13b of the filament 12.

The inductor 11 is contained, at least partly, in a substantially flat shell 24 consisting of two half-shells 25a, 25b, which are symmetrical with respect to the plane of symmetry of the device 10 which is parallel to the lying plane of a branch 13a, 13b of the filament 12.

The half-shells are respectively:

- a first half-shell 25a, which is substantially parallel to the lying plane of the first branch 13a of the filament 12, and is proximate to the first branch 13a,

- a second half-shell 25b, which is substantially parallel to the lying plane of the second branch 13b of the filament 12, and is proximate to the second branch 13b.

In particular, the support 23 has two opposite lateral grooves 26a, 26b with a longitudinal development, for the same shape coupling to a corresponding relief 27a, 27b of the half-shell 25a, 25b, respectively:

- a first lateral groove 26a, parallel to the lying plane of the first branch 13a of the filament 12, for the same shape coupling to a relief 27a of the first half-shell 25a,

- a second lateral groove 26b, parallel to the lying plane of the second branch 13b of the filament 12, for the same shape coupling to a relief 27b of the second half-shell 25b.

Each half-shell 25a, 25b is complementary and counter-contoured to the corresponding:

- electrode 16a, 16b,

- branch 13a, 13b of the filament 12,

- lateral groove 26a, 26b of the support 23.

The support 23 is at least partly protruding from the shell 24 and has a face 28 protruding from the shell 24, able to be facing and substantially parallel to the panel 1, during the operating phase of the device 10. The support 23 has, on the face 28, a seating 30 with a longitudinal development, which is defined by two opposite walls 29a, 29b that are reciprocally parallel and orthogonal to the lying plane of the face 28.

The following are inserted in the seating 30: - the second substantially rectilinear segment 21a, 21b of the branch 13a, 13b of the filament 12, in contact with a corresponding one of the walls 29a, 29b so that it is contained within the overall size of the support 23 and does not protrude from the face 28,

- the insert 14, so that it partly protrudes from the support 23 beyond the face 28 thereof.

In particular, the seating 30 of the support 23 has a housing 31 for the insert 14, which is contoured for the same shape coupling to a first end portion 32 of the insert 14, opposite to a second end portion 33 able to contact the header ribbon 2. The housing 31 is interposed between the first branch 13a and the second branch 13b of the filament 12.

Specifically, the insert 14 has a substantially T-shaped section, with:

- the first end portion 32, widened, corresponding to the wing of the T-shaped section, - the second end portion 33, corresponding to the base of the core of the T- shaped section, which is protruding from the face 28 of the support 23.

Between the insert 14 and the branches 13a, 13b of the filament 12, the support 23 comprises two longitudinal appendices, respectively:

- a first longitudinal appendix 34a between the core of the T-shaped section of the insert 14 and the second substantially rectilinear segment 21a of the first branch 13 a,

- a second longitudinal appendix 34b between the core of the T-shaped section of the insert 14 and the second substantially rectilinear segment 21b of the second branch 13b. Specifically, the insert 14 protrudes by approximately 0.7 mm from the support 23 and this allows to prevent a direct contact between the filament 12 and the header ribbon 2 during the soldering phase, which could cause a short circuit of the solder. The support 23 is made of plastic material such as, for example, polyoxymethylene (POM).

The operation of the device 10 according to the invention is as follows.

To proceed with the soldering between the header ribbon 2 and the bus bar ribbons (not shown in the drawings) of panel 1 :

- the device 10 is moved toward the panel 1, putting the insert 14 in contact, for a few seconds, with the header ribbon 2, previously positioned in contact with the bus bar ribbons,

- while the insert 14 presses the header ribbon 2, keeping said header ribbon 2 in contact with the bus bar ribbons for its entire length, an electric current is made to flow along the filament 12, generating a magnetic field between the two branches 13a, 13b, which heats and melts the tin that covers the header ribbon 2,

- at the same time, cold water is made to flow inside the filament 12, through the ducts 22a, 22b, in order to cool the branches 13a, 13b of the filament 12,

- due to the melting and crushing of the tin that covers the header ribbon 2 onto the bus bar ribbons, the first ribbon binds to the latter, creating, once solidification has occurred, the connection joints in correspondence with the reciprocal intersection points.

It should be noted that a similar device allows to heat the header ribbon homogeneously for the entire length of the insert, regardless of where the bus bar ribbons are positioned, and this makes the device according to the invention able to be used for any format whatsoever of photovoltaic panel.

In practice, it has been found that the invention achieves the intended aim and purposes, providing a device for soldering the interconnections of photovoltaic panels which can be used for any format whatsoever of photovoltaic panel and allows soldering for any format whatsoever of photovoltaic panel, regardless of the distance between the bus bars.

With the invention, we have perfected a device for soldering the interconnections of photovoltaic panels which does not require the need to replace the terminal in the event of a change in format of the panel to be produced, simultaneously increasing the productivity of the equipment with which it is associated, for the same amount of time, compared to similar devices of a known type. The invention thus conceived is susceptible to numerous modifications and variations, all of which are within the scope of the inventive concept; moreover, all the details can be replaced by other technically equivalent elements.

In practice, any materials, as well as contingent shapes and sizes, can be used according to requirements and to the state of the art, as long as they are compatible with the specific use.

Where the characteristics and techniques mentioned in any claim are followed by reference marks, such marks have been used for the sole purpose of increasing the intelligibility of the claims and consequently such reference marks do not in any way limit the interpretation of each element identified by way of example by such reference marks.