Patent Publication Number: US-2012043986-A1

Title: Junction box with test contact

Description:
RELATED APPLICATIONS 
     This patent application claims priority from and incorporates by reference German patent application 10 2010 034 633.0-55 filed on Aug. 17, 1010 
     FIELD OF THE INVENTION 
     The invention relates to a junction box, in particular for a solar module, including a base that is parallel to an assembly surface at the module and an inner cavity formed by a housing and closed by a cover, wherein a solar module contact is connected within the housing with a connecting conductor for putting out electricity that is being generated, wherein the conductor exiting the inner cavity is provided with a plug connector which is arranged in a support device at the junction box. 
     BACKGROUND OF THE INVENTION 
     Junction boxes of this type are known, for example, from DE 10 2007 023 210 B3 DE 10 2007 027 861 A1 and DE 10 2007 060 023 A1. 
     The need to support plug connectors of the connecting conductors through a support device at the housing substantially originates from the requirements of automatically producing solar modules. In order to produce solar modules in a fully automated manner the junction boxes to be mounted at the solar modules have to be deliverable in storage stacks in order to be machine feed able. Thus, the junction box is typically preassembled at the junction box manufacturer and provided with connecting conductors. In order to be able to deliver a neatly arranged stack the connecting conductors are directly secured at the junction box through plug-in connectors. 
     The defined arrangement of the plug connectors at the junction box is additionally used according to DE 10 2007 060 023 A1 to perform a functional check of the junction box. Thus, a test device contacts the contacts of the plug connectors and feeds electricity. Thus, various test procedures can be used to determine whether the connection between the plug connectors, connecting conductors and the functional components arranged within the junction boxes like, for example, bypass diodes are provided correctly. 
     However, it has become apparent that the position of the plug connectors and in particular of their connecting contacts as a function of their support devices at the junction box, the length of the connecting conductors and the weight load on the support devices resulting there from and as a function of additional influences has a certain tolerance. This necessitates complex control logics for the test robot which contacts the connection contacts of the plug connectors in order to perform a functional check of the junction box. 
     BRIEF SUMMARY OF THE INVENTION 
     Thus, it is an object of the invention to provide a junction box for fully automated production which provides a defined position of the contacts to be used by a testing device and a simplification of the test procedure. 
     The object is achieved by a junction box with a base that is parallel to a mounting surface for the solar module, an inner cavity formed by a housing and closed by a cover, a connecting conductor for putting out electricity generated by the solar module and connected in the inner cavity with a contact for the solar module, and a test contact that is accessible in a direction substantially perpendicular to the base, wherein the connecting conductor exits the inner cavity and is provided with a plug connector that is arranged in a support device at the junction box, the test contact is electrically connected with a connecting contact of the plug connector of the connecting conductor, and in a function of the junction box is testable through feeding an electrical voltage into the test contact, in particular with the characterizing features according to which a test contact that is essentially accessible in a perpendicular direction relative to the basis is provided which is electrically connected with a connection contact of the plug connector of the connecting conductor and through which the function of the junction box is testable through feeding an electrical voltage. 
     Differently from the known prior art test procedure through contacting the connection contacts of the plug connectors arranged in the support device at the junction box by moving horizontally parallel to a base, the invention provides a test contact that is contacted in a perpendicular direction relative to the base, thus in a perpendicular direction relative to the mounting surface of the solar module. This has significant advantages with respect to the test routine. This way mounting the junction box and functionally testing it through contacting the connection conductors and the solar module conductors can be provided in one process step and in particular in one movement. 
     While it was required in the prior art to connect the junction box at the solar module through a movement oriented perpendicular to the mounting surface of the solar module and to establish the connection between solar module connector and the connecting conductor mechanically through welding or soldering, and parallel thereto, or in a separate process step to contact the connecting contact of the plug connectors for testing through the testing tools, thus in a movement oriented parallel to the mounting surface of the solar module, both processes can now be combined. The tool head which attaches the junction box according to the invention at the solar module initially includes assembly tools for connecting the connecting conductor and the solar module conductor. The tool head furthermore includes the necessary test pins which engage the vertically accessible test contacts. Thus, a functional test of the junction box can be performed through the test contacts in parallel with the assembly process. 
     Since the junction boxes typically include a higher number of contacts for solar module conductors in their interiors compared to the number of outgoing connecting conductors which in turn are connected with one another, in particular through bypass diodes, a very precise functional check can already be performed when assembling the junction box. When the test contacts and thus also the connecting conductors and also the contacts arranged within the junction box are engaged by a test device, respective circuits can simulate any option of electrical current flow when operating a solar module. 
     In an exemplary embodiment it is provided that the connection contact of the plug connector and the test contact form separate components in particular that the test contact is arranged at the junction box housing. 
     The separate configuration of the test contact and its separate arrangement at the junction box housing provides a defined position of the test contact which is independent from the dimensional and production tolerances of the support device and the plug connectors or from weight influences of the cables arranged at the plug connector. 
     Thus, it is furthermore provided that the test contact based on the arrangement of the plug connector at the support device is in electrical contact with the connecting contact of the plug connector. Thus, it is provided that the connection between the connecting contact of the plug connector and the test contact is established through inserting the plug connector into the support device and no separate manipulations are required. 
     An embodiment that is advantageous is one in which the junction box housing forms a plug-in mechanism that is complementary to the plug connector and serves as a support device, wherein the plug connector is arranged at the plug-in mechanism. 
     Contrary to the prior art support clamps and similar support devices, using the original plug connector mechanism for supporting the plug connector at the junction box has a substantial advantage in that a secure support with defined position is provided. 
     Thus, it is being considered that the complementary plug-in mechanism supports the test contact which is electrically connected with its connecting contact when the plug connector is arranged and the test contact is accessible through an opening that is oriented substantially perpendicular to the base. 
     The invention furthermore relates to junction boxes in which the connecting contact of the plug connector is essentially only accessible in horizontal direction due to its arrangement in the support device. 
     For a correct positional arrangement of the junction box with respect to the assembly and test tools it is provided that the junction box includes centering mechanisms through which it can be centered relative to a test tool. 
     An alternative embodiment of the junction box provides that the test contact is formed by the connecting contact of the plug connector which is accessible through an opening in the plug connector which is oriented substantially perpendicular to the base. 
     This provides in particular an alternative to a separate test contact which is arranged according to the invention at the junction box. However, it is necessary to assure before feeding electricity that the opening for test tapping is closed. This can be provided, for example, through the tool for mounting the junction box after testing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is described in more detail based on an exemplary embodiment with reference to drawings, wherein: 
         FIG. 1  illustrates a junction box according to the invention in a perspective view; 
         FIG. 2  illustrates the junction box according to  FIG. 1  in a top view; and 
         FIG. 3  illustrates a sectional view of the junction box according to  FIG. 2  along the section line III-III with the plug connector arranged at the junction box. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The drawings illustrate a junction box for solar modules that is designated overall with the reference numeral  10 . 
     It is apparent from the perspective view in  FIG. 1  and the top view in  FIG. 2  of the junction box  10  according to the invention that the junction box includes a housing  11  which configures an inner cavity  12 . Soldering or welding contacts  13  are arranged in the cavity  12 , wherein the soldering or welding contacts  13  are electrically connected with the functional components embedded in the housing material, in particular with bypass diodes. The soldering or welding contacts  13  are attached at the solar module conductors (not illustrated) during assembly. 
     Connecting conductors  14  exiting the interior  12  of the housing are also electrically connected with the soldering or welding contacts  13 , wherein the connecting conductors put out the electrical energy generated by the solar module. At their free ends the connecting conductors  14  are respectively provided with a plug connector  15 . The visual separation of connecting conductors  14  illustrated in the drawings is only caused by the drawing technique. In fact the connecting conductors  14  form a non-interrupted strand which extends from the interior  12  of the housing to the plug connector  15 . 
     The base  16  of the junction box  10  is formed by its bottom side. The junction box  10  is arranged with its bottom side at the solar module which is not illustrated. 
     The housing  11  of the junction box  10  forms respective support devices  17  for the plug connectors  15 , wherein the support devices are arranged at the housing laterally adjacent to the inner cavity  12 . It is of particular importance that each support device  17  forms a shape complementary plug-in mechanism with the associated plug connector  15 . This means that the support device  17  forms the plug-in mechanism of a complementary plug for a plug connector  15  configured as a plug socket. The support device  17  includes a socket shaped plug-in mechanism for a plug connector  15  configured as a plug. 
     In addition to the plug-in mechanism complementary to the respective plug connector  15 , the support devices  17  respectively include a test contact  18  (cf.  FIG. 2 ) which is in turn configured plug-in complementary to the connecting contact  20  (c.f.  FIG. 3 ) of the respective plug connector  15 . A test tool can engage the test contacts  18  through vertically accessible openings  19  of the support devices  17 . 
       FIG. 3  illustrates a sectional view according the sectional line III-III in  FIG. 2 , wherein the plug connector illustrated in  FIG. 2  is inserted in  FIG. 3  into its associated support device  17 . 
     The illustration in  FIG. 3  shows how the connecting contact  20  of the plug connector  15  contacts the plug complimentary test contact  18  when the plug connector  15  is inserted into the support device  17 . 
     The junction box  10  according to the invention essentially has the following advantages. 
     Initially a junction box  10  is provided which forms a novel support device  17  for preassembled connecting conductors  14  and in particular their plug connectors  15 . Through configuring the support device  17  according to the invention as a plug-in mechanism that is complementary to the associated plug connector  15  the plug connector  15  is safely and precisely positioned at the junction box. This is important in particular in order to provide preassembled junction boxes  10  in stacks or magazines for the fully automated production of solar modules, wherein the junction boxes can be retrieved by production robots in a simple manner. 
     In conjunction with the recited advantage assembly and functional checking of the junction box  10  according to the invention is simplified considerably. The support device  17  is not only plug-in compatible with respect to the plug connector  15 . It is furthermore provided with a test contact which contacts the connecting contact  20  of the plug connector  15  when the plug connector  15  is applied to the support device  17 . 
     An opening  19  of the support device  17 , wherein the opening is oriented perpendicular with respect to the base  16  facilitates an access to the test contact  18  through a respective test tool. The base  16  is oriented parallel to the mounting surface of the solar module. 
     When mounting the junction box  10  on a solar module that is not illustrated the junction box is applied to the solar module in a perpendicular direction to the base  16  or in a perpendicular direction to the mounting surface of the solar module and attached. The tools engage the soldering or welding contacts  13  also in the perpendicular direction in order to connect them with solar module connecting conductors. Alternatively the contacts not illustrated herein are mechanically connected with solar module conductors through clamping in the same tool movement direction. 
     The junction box  10  according to the invention with its vertically accessible openings  19  and vertically accessible test contacts  18  now facilitates for the first time a purely vertical movement of the test tool for functional testing of the junction box  10  which is not possible in the prior art. The horizontal engagement of the connecting contacts of the plug connectors  15 , wherein the connecting contacts are not completely defined with respect to their positions, which was required in the prior art, thus can be omitted. This also yields another substantial advantage. The test contacts are configured in a clearly defined position as components of the junction box  10 . Contrary to the plug connectors  15  supported with a certain clearance tolerance in the support devices  17  according to the prior art the junction box according to the invention does not provide any position tolerance for the test contacts  18 . 
     Consequently the assembly tool for the junction boxes  10  can integrate all tools for assembling the junction boxes  10 , the solder/weld contacts  13  and for functional testing in an assembly line for solar modules so that assembly and functional testing can be combined into one process step. 
     In case it is required for assembly, centering bosses at the tools can engage the centering openings  21  at the junction boxes. Centering bars  22  with slanted surfaces  23  oriented towards the centering boss support the centering function. 
     The centering aids  21 - 23  can be used on the one hand side for centering the junction box  10  relative to the assembly tool when it is received in the assembly tool. The centering aids, however, can be used during an assembly process performed in plural steps and by plural tools for readjusting the junction boxes  10  on the solar panels when switching from one assembly tool to another. Thus, care only has to be taken that the attachment device between the junction box  10  and the solar module, typically a gluing device cures respectively slowly and facilitates re-centering the junction box  10  during the particular assembly steps. 
     REFERENCE NUMERALS AND DESIGNATIONS 
     
         
           10  junction box 
           11  housing of  10   
           12  inner cavity 
           13  solar module soldering/welding contact 
           14  connecting conductor 
           15  plug connector 
           16  base 
           17  support device 
           18  test contact 
           19  opening 
           20  connecting contact of  15   
           21  centering opening 
           22  centering bar 
           23  slanted surfaces