Abstract:
A connection and junction box for a photovoltaic solar module having flexible flat conductor bands protruding from the surface of the solar module, wherein the connection and junction box has an insertion mouth at its side in mounting state facing the solar module, for at least one of the flexible flat conductor bands of the solar module, as well as comprising a housing for attaching to the solar module, and a connection device for the flexible flat conductor band, positioned in the housing, the connection device has a deflection arm and an electrical contact clamp, which is actuated when attaching the box to the solar module for bending and contacting the flat conductor band.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a connection and junction box for a photovoltaic solar module having flexible flat conductor bands protruding from the surface of the solar module, and to a method for connecting a connection and junction box to a solar module. 
       BACKGROUND OF THE INVENTION 
       [0002]    Over the past years, producing photovoltaic solar modules has literally been booming, inter alia due to the increased demand on environmentally sound energy production. The direct conversion of sunlight into electric current by means of photovoltaic solar modules is entirely emission-free, and no risks for humans and the environment are almost involved. For example, complete roofs of new buildings are therefore recently overlaid with solar modules, and even “solar power plants” are built. Due to the technical development of photovoltaics, using solar modules more and more becomes efficient even in more unfavourable latitudes such as Middle Europe and Northern America so that especially in these regions there is a great demand. Due to the continuous progress of the efficiency of solar modules due to technical further development on the one hand as well as increasing costs of energy production with other energy carriers as fossil fuels or nuclear energy, photovoltaic power generation becomes more and more competitive. 
         [0003]    It is apparent that the success of solar modules in economic competition with other energy carriers depends on the costs of producing and mounting the solar modules. 
         [0004]    Typically, solar modules consist of a plurality of solar cells based on semiconductor technique, which cells are interconnected to large-scale solar panels. A typical solar module has a glass plate on its side facing the sun, and a transparent plastics layer on the rear side, in which layer the solar cells are embedded. Typically, the rear side of the solar module is covered with a weather-resistant plastics compound foil, for example polyvinyl fluoride and polyester. The mono- or polycrystalline solar cells are electrically interconnected to each other by means of small solder wires. Typically, the solar module is furthermore mounted in a metal profile frame for fixing and stiffening the compound. Therefore, a solar module basically is a two-dimensional entity, similar to a glass plate. 
         [0005]    Typically, solar modules have thin flexible conductor bands on the side facing away from the sun. These bands are mostly made of copper and vertically protrude from the rear side of the solar module. These flexible conductor bands are very sensitive and therefore difficult to contact. Additionally, a mechanical charge for fixing an electrical connector is also difficult because of the disk-like form of the solar module. Therefore, a special kind of electrical connectors has evolved for such solar modules, which kind is called connection box or connection and junction box. Typically, the connection and junction box is glued on the rearward surface of the solar module, and has electrical connection devices inside for contacting the flexible flat conductor bands of the solar module. Furthermore, if needed, the connection and junction box has an apparatus for connecting an electrical connection cable, which is connected with the flexible flat conductor band of the solar module by means of the connection and junction box for conducting the electrical current generated by the solar module. 
         [0006]    Furthermore, several solar modules are typically operated in series connection, wherein a so-called bypass diode or free-wheeling diode is anti-parallel connected to each module. Inside the connection and junction box, the free-wheeling diode is connected to the electrical connection device. If a module is shaded or does not produce electricity because of a defect, this module would lower the power of the solar modules in series connection or even suffers damage without bypass diode. This is avoided by the bypass diode, because the current flows through the diode and is sustained. 
         [0007]    It is apparent that due to the mechanical conditions, particularly the form of the solar module and the sensitiveness of the flexible flat conductor bands, a number of difficulties occur, when constructing the connection and junction box. Up to now, connection boxes are known, which are put over the flexible flat conductor bands. When doing so, the flexible flat conductor band is manually bent and contacted by means of a contact clamp or a soldered connection. The connection box is closed in a further process step. Such connection arrangements or connection boxes respectively are described in DE 10 2005 025 632 A1 and DE 20 2005 018 884 U1. It is apparent that mounting such connection devices or connection boxes respectively is laborious, and is badly suited for automated mass production. 
         [0008]    An electrical connection and junction box for a solar module is known from DE 103 58 140 B4, which box has a guiding arrangement at its lower side. The thin conductor band is guided in this guiding arrangement in lateral direction with low slackness in order to avoid buckling or folding the conductor bands, when inserting into the clamp apparatus. At this, it is disadvantageous that the conductor band has to be threaded into the narrow guiding arrangement, and the clamping force of the clamp arrangement may nevertheless be relatively low to be able to insert the thin conductor band into the clamp arrangement. 
         [0009]    After all this, there is need for improvements in this regard, due to the high pressure to innovate in producing solar modules. 
       SUMMARY OF THE INVENTION 
       [0010]    Therefore, it is an object of the present invention to provide a connection and junction box for a photovoltaic solar module, which box can automatedly, for example by means of a robot, be connected to the solar module, and offers high contact reliability and long-life cycle. 
         [0011]    It is a further object of the invention to provide such a connection and junction box, which has a kind of tolerance concerning the lateral positioning on the solar module. 
         [0012]    It is a further object of the invention to provide such a connection and junction box, which avoids, or at least lowers the disadvantages of the state of the art, and may cost-effectively be produced as well as be mounted. 
         [0013]    According to the invention, a connection and junction box with flexible flat conductor bands protruding from the surface of the solar module is provided. At its side facing the solar module in mounting state (hereinafter referred to as lower side), the connection and junction box has an insertion mouth for at least one flexible flat conductor band of the solar module as well as a housing for attaching to the solar module. In the housing there is a connection device for the flexible flat conductor band. 
         [0014]    The connection device has an electrical contact clamp for establishing a clamp contact with the flexible flat conductor band, wherein the contact clamp may be in at least two defined stable states, namely an opened mounting state, in which an open or free insertion area is defined, into which is the flat conductor band is substantially resistance-less insertable, and a closed contact state, in which a clamp contact is established with the flat conductor band clamped between the two clamp elements of the contact clamp. Furthermore, the connection and junction box comprises a deflection arm inside the housing, which arm bends the flexible flat conductor band into the open insertion area of the contact clamp after inserting through the insertion mouth into the connection and junction box such that the flexible flat conductor band is gripped by the contact clamp and electrically contactable only after insertion. 
         [0015]    The connection and junction box according to the invention may easily be mounted, particularly by means of a robot arm. It is advantageous that the flexible flat conductor band is inserted in a resistance-less, and even contactless manner, if needed, into the insertion mouth besides the contact clamp, and therewith outside the contact or insertion area so that damaging the sensitive flat conductor band is avoided. Particularly, the insertion mouth may be chosen relatively large so that there is a kind of tolerance concerning the lateral arrangement of the connection and junction box on the solar module, and that it is avoided that the conductor band abuts against parts of the connection and junction box. 
         [0016]    Furthermore, due to bending the flat conductor band may course diagonally or even parallelly to the surface of the solar module at the clamp position so that the clamping force of the contact clamp may act diagonally or even perpendicularly to the surface of the solar module. Furthermore, bending causes some movability of the flat conductor band, what may contribute to long-life cycle. 
         [0017]    Operating the deflection arm is preferably effected by a first actuation element, which is mounted at the housing, and is built in one piece with the housing, if needed. Purposefully, the first actuation element is constructed in the form of a cam, which applies a force to the deflection arm. For this, the housing and the connection device are two-parts and movable with respect to each other. In response to a movement of the housing relatively to the connection device, the cam actuates the deflection arm, in order to thus automatically cause bending the flexible flat conductor band. 
         [0018]    Preferably, the housing has a second actuation element, which also automatically closes the contact clamp in response to the movement of the housing relatively to the connection device in order to establish the electrical contact with the flat conductor band, after this was bent off by the deflection arm into the insertion area still being open during bending. For example, the second actuation element is constructed as actuation pin, protruding into the housing and is formed integrally with the housing. But also the housing cap itself may serve as first and/or second actuation element, if this is permitted by the spatial arrangement. Thus, the contact clamp is actively closed by means of the second actuation element not until the flat conductor band is inserted into the contact clamp so that the sensitive flat conductor band does not need to press open the contact clamp, as it is the case with other connection and junction boxes. 
         [0019]    The relative movement of the housing and the connection device is preferably implemented as linear shifting, i.e. that a sliding arrangement is provided between the housing and the connection device. Furthermore, actuating the deflection arm and the contact clamp takes place after each other so that with the attaching process in response to the relative movement, the first actuation element firstly actuates the deflection arm, and then the second actuation element closes the contact clamp in order to finally establish the electric contact with the flat conductor band. In the closed contact state, the flat conductor band is clamped in the contact clamp with a predefined clamping force. 
         [0020]    According to a simple arrangement, the sliding arrangement comprises a guide sleeve at the connection device and an alignment pin at the housing, or vice versa. Alignment pin and guide sleeve are self-locking, wherein the locking or gripping may be overcome by a predefined application of force so that the housing may be taken by a robot arm, and attached to the solar module from above. But when doing so, the connection device in the housing is secured against falling off. In this first or mounting state, the connection device protrudes from the housing so that firstly, only the connection device engages the solar module, when being attached. In a further continuation of the mounting process, a force is applied to the housing in a direction orthogonal to the solar module, wherein the connection device supports itself on the solar module. By applying a force, the gripping between the housing and the connection device is overcome so that with the housing moving relatively to the connection device, the housing is shifted till it engages the solar module. Due to the relative movement, the deflection arm is actuated and the contact clamp is closed one after the other inside the housing. 
         [0021]    This has the advantage that in case of an automated mounting of the connection and junction box on the solar module, only one work step with a linear movement has to be carried out. This is particularly easy for a mounting robot. 
         [0022]    The deflection arm purposefully comprises a holding section, which is attached to the connection device, and a bending arm bending off the flexible flat conductor band. The holding section and the bending arm are one-piece connected with each other by means of a notch hinge so that the bending arm can be pivoted with respect to the holding section. 
         [0023]    Preferably, the contact clamp has a clamp spring and a counter clamp element, of which at least one of the two has electric contact section, and wherein the electric contact with the float conductor band is closed by means of an active movement of the clamp spring or the counter clamp element, in response to actuation by means of the second actuation element. For this, it may easily be implemented to pivotably mount the clamp spring at the connection device, and to close the electric contact with the flat conductor band by means of pivoting the clamp spring, in response to the actuation by means of the second actuation element. At this, a clamp section of the clamp spring covers the catch area between the clamp spring and the counter clamp element for catching the bent flat conductor band. Thereby, the catch area is preferably relatively large during bending. It is free of resistance and barriers so that the danger of damaging the flat conductor band is avoided during bending. 
         [0024]    In a preferable manner, a high and predefined clamp and contact force may be generated by means of actively closing the contact clamp after inserting and bending the flat conductor band. 
         [0025]    According to one preferred embodiment of the invention, the leaf spring-like clamp spring has an actuation section, by mean of which the second actuation element of the housing acts together for closing the contact clamp, wherein the actuation section comprises a curved and an substantially linear section of the clamp spring. Hereby, a constant clamp and contact force is ensured so that contacting has a permanent quality. 
         [0026]    Purposefully, the contact clamp has s metallic and generally U-shaped holding frame, in which the clamp spring is pivotably mounted in bearing openings by means of bearing studs. The holding frame is slotted towards the bearing openings so that the bearing studs can be inserted through the slots during pre-mounting the connection and junction box, Preferably, a cable connection clamp is additionally provided at the holding frame for connecting the connection cable, i.e. preferable a stripped round conductor. Preferably, the cable connection clamp has a second clamp spring for closing the electric contact with the connection cable. 
         [0027]    Furthermore preferably, the contact clamp has a latching mechanism, by means of which the clamp spring is latched in the contact state, for example by latching notches of the clamp spring in the holding frame. In the closed and latched state, the contact clamp is under a predefined tension. Furthermore preferably, the contact clamp has a clamp mechanism holding the contact clamp in the open position. For closing the contact clamp, the gripping of the clamp mechanism is overcome by applying a force by means of the second actuation element. 
         [0028]    Preferably, the connection device has a dielectric carrier, at which the guide sleeves are preferably one-piece are fastened, and in which carrier the holding frame is latched by means of reciprocal snap-fits. Thus, the dielectric carrier forms the bottom of the connection and junction box. 
         [0029]    In the following, the invention is described in more detail on the basis of exemplary embodiments, and with reference to the figures, wherein same and similar elements are partially provided with the same reference numerals. Furthermore, it is apparent that orientation specifications like “below” or “lower side” are not to be understood in the sense of absolute orientation in space, but relatively with respect to the solar module, because the connection and junction box is mounted on the averted “rear” side when operating the solar module. Therefore, the lower side indicates the side facing the solar module, when mounted. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    It is shown: 
           [0031]      FIG. 1  a perspective view from above onto the housing of the connection and junction box, 
           [0032]      FIG. 2  a perspective vied from below onto and into the housing of the connection and junction box, 
           [0033]      FIG. 3  a cross-section of the connection and junction box with the electric connection device in open mounting state, across the solar module, 
           [0034]      FIG. 4  a cross-section of the connection and junction box with the electric connection device in intermediate state, across the solar module, 
           [0035]      FIG. 5  a cross-section of the connection and junction box with the electric connection device in closed contact state, across the solar module, and 
           [0036]      FIG. 6  a perspective, partially sectional view of the connection device. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]    With reference to  FIGS. 1 and 2 , the connection and junction box has a housing made from plastic. The housing  2  is provided by an substantially rectangular frame consisting of four side walls  2   a  to  2   d , and a closed cap  2   e , which connects the four side walls and proceeds parallelly to the solar module. The five-sided, closed housing  2  being open downwards is die cast in one piece, for example. The connection cable (not shown) is guided outwards through connection cable feedthroughs  4 . 
         [0038]    With reference to  FIG. 2 , the housing  2  is open downwards, and has a protruding holding frame  8  with a circular glue notch  10  so that the housing  2  has a hat-like form. The housing is permanently glued on the solar module, and sealed by means of the glue brought into the glue notch  10 . The hat-like or pan-like form of the housing defines an internal hollow space  12 , in which the connection device not being shown in  FIG. 2  is substantially waterproof housed in mounting state. The connection device may, but does not need to, additionally be glued on the solar module by means of a thin glue layer. 
         [0039]    Alignment pins  14  protrude from the lower side of the housing cap  2   e  into the hollow space  12 . Furthermore, the lower side of the housing cap  12   e  has a first actuation arrangement  16  in the form of lateral cam for actuating the deflection arm (not shown in  FIG. 2 , see hereunto  FIGS. 3-5 ). Furthermore, actuation pins  18  for actuating the contact clamp protrude from the housing cap  12   e  into the internal space  12 . In this embodiment, the actuation arrangements  16  and  18  are integrally formed with the housing. 
         [0040]    With reference to  FIGS. 3-5 , the connection device  20  of the connection and junction box  1  is arranged in the housing  2 .  FIG. 3  shows the connection and junction box, after it was put over the flat conductor band. When being put over, the connection and junction box in a first state, the mounting state, in which the deflection arm is in a first position. The insertion area  30  over the insertion opening  26  is kept free, and the contact clamp  22  is open, in the mounting state, in which the connection and junction box is preferably delivered. 
         [0041]    The connection device  20  has guide sleeves  15 , into which the alignment pins  14  are inserted. The alignment pins  14  clamp in the associated guide sleeves  15  such that when putting the connection and junction box  1  on the solar module  24 , the connection device  20  is fixed in the housing  2  by gripping so that the housing may be caught and automatedly put on top by a robot, without the connection device falling off. On the other hand, the gripping between the alignment pins  14  and the guide sleeves  15  may be overcome by applying a force for shifting the housing  2  with respect to the connection device  20  to be possible. In this example, the guide sleeve has slots for improving the gripping interaction with the alignment pin  14 . 
         [0042]    In the mounting state shown in  FIG. 3 , the connection device  20  is not yet completely inserted into the housing  2 , i.e. it protrudes a little (some millimetres) downwards from the housing  2 , i.e. at the side facing the solar module. In the mounting state, therefore, there is an offset between the lower side  20   a  of the connection device  20  and the holding frame  8  of the housing  2  so that when putting on the connection and junction box  1 , firstly the connection device  20  comes in contact with the solar module  24 . In this state being shown in  3 , the holding frame  8  is still spaced apart from the surface  241  of the solar module  24 . 
         [0043]    The connection and junction box  1  has a relatively large insertion opening  26  at its lower side facing the solar module  24 . In the mounting state, this makes sure that the sensitive, flexible flat conductor band  28 , the so-called “ribbon”, is barrier-free and resistance-less inserted from below into the connection and junction box  20 . The danger of damaging the flat conductor band  28  is hereby reduced. In this state, the connection and junction box  1  defines an open insertion area  30  being between the contact clamp  22  and the deflection arm  21 , into which area the flat conductor band  28  resistance-less immerges from below, when putting on the connection and junction box. Preferably, the contact clamp  22  or the deflection arm  21  do still not touch the flat conductor band  28 , in this state. 
         [0044]    Now a force is applied to the housing  2  against the solar module  24  for contacting the flat conductor band, wherein the connection device supports itself at the solar module  24 . Hereby, a linear movement of the housing  2  with respect to the connection device  20  is caused to that effect that the housing  2  is slided over the connection device till the holding frame  8  with the glue (not shown) in the glue notch  10  engages the surface of the solar module  24 , and till the lower side of connection device  20  and the housing  2  shortly abuts on the solar module  24 . This closed state is the final or operating state, and is shown in  FIG. 5 . In the operating state, the housing  2  is glued on the solar module by means of the glue being in the glue notch  10 . 
         [0045]    But before the connection and junction box  1  reaches the final state, it passes through the intermediate state being shown in  FIG. 4 , in which state the flat conductor band  28  is already bent, and the contact clamp  22  is still open. When attaching the connection and junction box  1 , first of all the flat conductor band  28  is inserted into the insertion area  30 . After the lower side  20   a  of the connection device  20  has engaged on the solar module  24 , the flat conductor band  28  is successively bent into the catch area  31  of the contact clamp  22  by means of the deflection arm  21 . Further successively, the contact clamp  22  is actively closed by means of the second actuation element  18 . Therefore, the connection and junction box  1  defines three predefined states, namely the mounting state ( FIG. 3 ), in which the deflection arm  21  is in a first position so that the insertion area is free, and the contact clamp  22  is open; the intermediate state ( FIG. 4 ), in which the flat conductor band  28  is bent by the deflection arm  21  into to the catch area  31  of the still open contact clamp  22 ; and the final or operating state ( FIG. 5 ), in which the contact clamp  22  is closed, and the electric contact with the flat conductor band  29  is established by means of clamp contacting. 
         [0046]    With the shift of the housing  2  with respect to the connection device, the first actuation element  16 , in this example an actuation cam, therefore interact with the deflection arm  21 , and successively, the second actuation element, in this example an actuation pin, interacts with the clamp spring  32 . Due to this successive actuation, firstly the bending section  21   a  of the deflection arm  21  is deflected in response to actuating by means of the cam  16 . Successively, the contact clamp  22  is closed by pivoting the clamp spring  32 . In this example, the cam  16  is formed as lug of the side wall of the housing  2 , integrally form with the latter. Thereby, the clamp section  34  of the clamp spring  32  covers the catch area  31  of the contact clamp, and clamps and contacts the free end of the flat conductor band  28  between the clamp section  34  of the clamp spring  32  and the two-was clamp element  35 . The bending section  21   a  of the deflection arm  21  is one-piece connected with a holding section  21   c  by means of a fold hinge  21   b . The holding section  21   c  is attached to the connection device  20 . 
         [0047]    The clamp spring  32  has an actuation section  38 , which is divided into a curved section  40 , and a substantially linear section  42 . When closing, the actuation element  18  firstly acts on the curved section  40  (see  FIG. 4 ), and tightens against the linear section  42  in the closed contact state (shown in  FIG. 5 ) of the connection and junction box  1 . I.e. when closing, the actuation element  18  covers the actuation section  38  of clamp spring  32 . 
         [0048]    With reference to  FIG. 6 , in this example, the connection device  20  comprises two contact clamps  22  and two cable connection clamps  46  for the respective electric connection cable not being shown. In this example, the cable connection clamp  46  is also provided with a clamp spring  48 . Here, also other connection types such as screwing terminals may be used. It is apparent that the invention can also be provided with only one contact clamp, or with more than two contact clamps. 
         [0049]    Furthermore, the connection device has a dielectric carrier  50 , preferably made from plastic, which carrier has a base plate  50   a , whose lower side defines the primary joint surface to the solar module  54 , and to which plate the contact clamps are attached. The contact clamp has a substantially U-shaped, metallic holding frame  51  preferably made from copper, which frame is locked at the carrier  50  bay means of snap-fits. 
         [0050]      FIG. 6  shows the contact clamp  22  in the open state. The clamp spring  32  has two latching studs  54 , which are resolvably clamped in recesses  53  in the metallic holding frame  51 , in the open mounting state. In the contact state, the contact spring  32  is pretensioned against the counter clamp  36 , and the latching studs  54  are latched behind corresponding lugs  55  in the metallic holding frame  51  (see  FIG. 5 ). This provides for a permanent and secure electric contact. 
         [0051]    Furthermore, the clamp spring  32  is mounted in slotted bearing openings  58  by means of bearing studs  56 . Therefore, the clamp spring  32  may easily be inserting, when mounting the connection and junction box, and is secured due to the position of the flat bearing stud  56 , which position is rotated with respect to the slot  60  in the mounting state and in the contact state. The clamp spring  32  is punched from sheet steel, and substantially U-shaped curved. 
         [0052]    The metallic holding frame  51  may furthermore have a dielectric connection element for the bypass-diode. 
         [0053]    Referring again to  FIGS. 3-5 , the bending section  21   a  of the deflection arm  21  and the clamp spring  32  are consecutively caused to pivot because of the housing  2  and the connection device  20  acting together by means of the actuation elements  16  and  18 . At the end of the pivoting, the clamp spring latches with its latching studs in the metallic holding frame  51 , when in contact state or in operating state. By pretensioning the clamp spring  32 , a permanent and predefined pressing force between the flat conductor band  28  and the conducting counter clamp element  16  is established. 
         [0054]    It is apparent to the person skilled in the art that the above described embodiments should be understood as examples, and that the invention is not limited to them, but can be varied in a variety of ways without leaving the scope of the invention. E.g., the connection and junction box may have a plurality of contact clamps for contacting a plurality of flat conductor bands in one box. Furthermore, it is apparent that the features also individually define essential parts of the invention, even if they are commonly described together with other features, not depending, whether they are disclosed in the description, the figures, or otherwise.