Abstract:
An electrical-connection device, particularly for photovoltaic-cell panels, has: a first electrical terminal, designed to be connected to apparatuses for generation or use of electrical energy and to extend in a fixed position through a wall for support of the connection device; a seal for fluid-tight coupling of the first electrical terminal to the supporting wall; a second electrical terminal connected to the first electrical terminal and to an electrical wiring external to the supporting wall; and an electrically insulated liquid-tight chamber, housing at least partially the first electrical terminal and the second electrical terminal.

Description:
The present invention relates to an electrical-connection device, particularly for photovoltaic-cell solar panels, to which the ensuing treatment will make explicit reference, without this implying any loss in generality. 
   BACKGROUND OF THE INVENTION 
   In general, the present invention finds advantageous application in all those cases where it becomes necessary to provide an electrical connection between two environments, which must be kept electrically insulated and in at least one of which there may be envisaged the presence of a liquid. 
   In the specific field of photovoltaic-cell solar panels it is known to use panels comprising an external fluid-tight casing permeable to light, housed in which is a plurality of photovoltaic cells immersed in a liquid. 
   Following upon exposure of the panel to solar radiation and to the normal activity of the photovoltaic cells, the photovoltaic cells themselves convert part of the incident solar energy into electrical energy that is transferred on the outside via different electrical-connection devices, which, in some cases, prove to be relatively complex and costly and, in others, decidedly simpler but with an unsatisfactory level of efficiency, reliability, and safety over time. 
   SUMMARY OF THE INVENTION 
   The aim of the present invention is to provide an electrical-connection device, particularly for solar panels, which will present a high and invariant efficiency and functional reliability and a particularly contained cost. 
   Provided according to the present invention is an electrical-connection device, particularly for photovoltaic-cell panels, comprising a first electrical terminal, designed to be connected to means for generation or use of electrical energy and to extend in a fixed position through a wall for support of the connection device; sealing means for fluid-tight coupling of said first electrical terminal to said supporting wall; a second electrical terminal, connected to said first electrical terminal and to an electrical wiring external to said supporting wall; and an electrically insulated fluid-tight chamber, housing at least partially said first and second electrical terminals. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described with reference to the annexed plates of drawings, which illustrate a non-limiting example of embodiment thereof, and in which: 
       FIG. 1  is a cross-sectional illustration of a preferred embodiment of the electrical-connection device according to the present invention coupled to an external casing of a solar panel; and 
       FIG. 2  is an exploded perspective view of the device of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   In  FIGS. 1 and 2 , designated by  1  is a fluid-tight electrical-connection device, particularly, but not exclusively, for a photovoltaic-cell solar panel  2 , to which the ensuing treatment will make explicit reference, without this implying any loss in generality. 
   In the particular example described, the photovoltaic solar panel  2  ( FIG. 1 ) comprises a shell or external casing  3 , which in turn comprises a rear wall or tray  4 , a front wall  5  facing the wall  4  and made of a material permeable to light, for example glass, and two terminal closing elements, not visible in the attached figures. 
   The front wall  5  and rear wall  4 , and the terminal closing elements delimit between them a fluid-tight chamber  6 , which houses a plurality of photovoltaic cells  7  supported in fixed and pre-set positions by an attachment and supporting plate  9 , which is also housed in the fluid-tight chamber  6  and made at least in part of metal material. Within the chamber  6 , the photovoltaic cells are at least partially embedded in a cooling liquid, which is made to circulate inside the chamber  6  itself via a hydraulic circuit connected to a heat exchanger (not illustrated) external to the chamber  6 . 
   The photovoltaic cells  7  are connected to an external electrical wiring  10 , terminating with a cable lug or eyelet  11  via the device  1 , which comprises a screw  12  made of metal material that forms a terminal for electrical connection of the photovoltaic cells  7  with the outside. The screw  12  comprises a head  13  housed in the chamber  6 , set bearing upon a shoulder  14  provided on the plate  9  and on the wall  4  and blocked in an angularly fixed position with respect to the plate  9 . The screw  12  comprises, then, an externally threaded stem  15  extending through two through holes  16  and  17 , which are made in the plate  9  and, respectively, in the rear wall  4 , coaxially to an axis  12   a  of the screw  12 . Fitted on the stem  15  is an annular seal  19  comprising, starting from its free end facing the head  13  of the screw  12 , a cylindrical end stretch  20  extending through the hole  16  and set bearing upon the head  13  of the screw, an intermediate cylindrical stretch  21  extending through the hole  17  and having an outer diameter larger than that of the cylindrical stretch  20 , and a terminal flange  22  set bearing upon an outer surface  4   a  of the rear portion  4 . Screwed on the stem  15  of the screw  12  is an internally threaded blind cylindrical portion  24  of a cap nut  25  made of metal material, a milled external terminal flange  26  of which tightens the flange  22  against the rear wall  4   a  to form a fluid-tight seal. Fitted on the blind cylindrical portion  24  is the cable lug  11 , which extends, together with a terminal stretch of the wiring  10 , within a pipe-like body  27  made of insulating material for electrical insulation from outside of the cable lug  11  and the cap nut  25 . 
   The pipe-like body  27 , which, together with the cap nut  25 , the seal  19 , and the cable lug  11 , forms part of the electrical-connection device  1 , comprises a barrel-shaped hollow portion  28 , which surrounds the cable lug  11 , the cap nut  25 , and the flange  22  of the seal  19 . The pipe-like body  27  moreover comprises a hollow appendage  30 , which radially and integrally extends from the barrel-shaped portion  28  and envelops the electrical wiring  10  and part of the cable lug  11  in a fluid-tight manner. The barrel-shaped portion  28  is set bearing upon the surface  4   a  of the wall  4  and is coupled to the surface  4   a  itself in a fluid-tight manner via two concentric front sealing projections  32  made in a single piece with the barrel-shaped portion  28  itself. The portion  28  partially houses a mushroom-shaped body  33 , which forms part of the pipe-like body  27  and closes the portion  28  in a fluid-tight manner. The body  33  comprises a head  34  with a slot for a screw-driver set bearing upon a front surface of the barrel-shaped portion  28  and coupled to the front surface itself in a fluid-tight manner by a front annular sealing projection  35  made in a single piece with the barrel-shaped portion  28  itself. The body  33  moreover comprises a hollow stem  36 , which terminates bearing upon the cable lug  11  and delimits a blind hole  37 , housing, with radial play, the blind cylindrical portion  24  of the cap nut  25 . Blocked in the stem  36  in a fixed position and coaxially to the axis  12   a  is a tightening nut  38 , which is screwed on an externally threaded terminal stretch  39  of the blind cylindrical portion  24  for gripping the cable lug  11  between the cap nut  25  and the flange  26  and forcing in a fluid-tight way the projections  32  against the surface  4   a  of the rear wall  4  and the projection  35  against its head  34 . 
   Installation of the device  1  is performed as defined in what follows. During assembly of the solar panel  2 , the screw  12  is coupled to the plate  9 , and then the seal  19  is inserted in the holes  16  and  17  and the flange  22  brought to bear upon the surface  4   a . At this point, the cap nut  25  is screwed on the stem  15  until it forces the flange  22  against said part and insulates the chamber  6  from the outside in a fluid-tight manner, after which the cable lug  11 , previously housed in the barrel-shaped body  28  is fitted on the portion  24 , brought to bear upon the flange  26  and tightened against the flange itself via the lid  33 , the nut  38  of which is screwed on the portion  24  itself and gripped by pack-tightening together the plate  9 , the tubular portion  28 , and the cable lug  11 , to form in this way an external fluid-tight chamber  40  insulated from the chamber  6 . 
   From the foregoing, it appears evident how the characteristics of implementation of the device  1  described, on the one hand, render the chamber housing the photovoltaic cells fluid-tight preventing any leakage of liquid or entry of external agents into the chamber itself and, on the other, insulate electrically from outside the cable lug  11 , part of the corresponding electrical wiring and the stem of the screw  12  for electrical connection through the casing by enclosing them in a dedicated chamber. Since the chamber  40  is fluid-tight, it receives and withholds any possible leakage of fluid from the chamber  6 , preventing the fluid from being dispersed into the surrounding environment, thus contaminating it, once again, however, without ever jeopardizing the electrical functionality of the solar panel. It is therefore evident that the device  1  described presents an efficiency and reliability that are not only high but are practically invariant over time. 
   From the foregoing, it appears evident that modifications and variations may be made to the device  1  described herein, without thereby departing from the scope of protection defined by the claims. 
   In particular, the screw  12  could be different from the one indicated and, for example, of the stud-screw type with a terminal or intermediate portion screwed in a threaded through hole of the plate  9 . 
   Finally, from the foregoing it appears evident that the device  1  described can find applications different from the one indicated and, in particular, in all the cases in which is it becomes necessary to make a fluid-tight electrical connection through a wall separating two environments, at least one of which houses or is traversed by a liquid.