Connecting device for connecting an electrical conductor to a solar module and method for the production thereof, together with a solar module with such a connecting device

A connecting device that connects to at least one external electrical conductor of a photovoltaic solar module. The connecting device includes a plurality of busbars, a support element, a housing, a diode and a contact. The plurality of busbars are arranged next to one another, while the support element is attached to the plurality of busbars and includes a bottom face to be positioned on the solar module. The housing is positioned over the support element and the plurality of busbars and includes an edge surrounding the support element and the plurality of busbars when the overhousing is positioned on the solar module. The diode fits onto the plurality of busbars and includes diode leads that fit onto one of the plurality of busbars, such that the plurality of busbars are connected together through the diode.

FIELD OF THE INVENTION

The present invention relates to a connecting device and in particular to a connecting device for connecting at least one external electrical conductor to an electrical connection system of a photovoltaic solar module.

BACKGROUND

A photovoltaic solar module typically includes a panel-type multilayer arrangement with solar cells arranged therebetween, which generate electricity through a photovoltaic effect. For example, a multilayer arrangement of such a solar module includes a flat layer on the side exposed to light for instance in the form of a glass cover with low absorptivity and a flat second layer, which is arranged on the back of the solar module and takes the form for example of a rear glass cover. The solar cells are arranged in a corresponding space between these layers and are interconnected within the multilayer arrangement with an electrical connection system. Embodiments of solar modules are known, in which the electrical connection system of the solar cells on the rear of the solar module remote from the light-exposed side is connected on the outside by means of electrical conductors, for example in the form of connecting foils, for example to a consumer. These connecting foils are connected in a connecting device, for example in the form of a terminal box or a junction box, to one or more electrical conductors of a connecting lead, or “solar connecting lead”. Accordingly, such a connecting device includes a current-carrying arrangement disposed in a connector housing, to which are connected, on the one hand, one or more connecting foils of the solar module and, on the other hand, one or more electrical conductors of one or more connecting cables. In addition, one or more diodes are generally contained in such a connecting device, which are provided in order to prevent circulating currents between sunlight-exposed solar cells and shaded solar cells, which supply different solar currents and solar voltages. By means of such “bypass diodes”, it is possible to continue operating the module even when it is partially shaded and with corresponding reduced power.

A connection device for connecting external connecting cables to a solar panel is known, for example, as disclosed JP 2004 134 717 A. The connection device described therein includes a printed circuit board, on which a plurality of conductor tracks are arranged, in order to connect an electrical connection system of a solar panel to a respective connecting cable. Furthermore, a plurality of diodes are mounted on the printed circuit board, which in each case connect two of the conductor tracks together. The connecting cables to be connected to the printed circuit board are in each case positioned on one of the conductor tracks applied to the printed circuit board and connected thereto, before a housing is mounted on the arrangement and connected to the solar panel. The housing has a housing edge surrounding it, which is placed onto the solar module. A cavity formed between printed circuit board and housing is then filled with a potting material. The above-described connection device has a disadvantage in that a main body in the form of a printed circuit board is needed, on which the respective diodes are positioned with bent diode leads. In this way, a current-carrying arrangement is obtained in the housing which is comparatively inflexible to handle and which it is difficult or impossible to adapt to different requirements, such as for example to a different number of solar module solar cells to be connected.

EP 0 999 601 A1 describes a another known and comparable connection device, in which, however, a plurality of bypass diodes are connected in the upper housing to corresponding terminals, before the housing is fitted with its bottom opening over a lower connection arrangement on the solar panel, at which the individual conductors of the solar module lead out and are connected to corresponding terminals. On application of the upper housing, the terminals thereof are connected to respective terminals of the lower connection arrangement. In the event of a defect in one of the bypass diodes, the connection device is repaired by replacing the entire upper housing.

SUMMARY

It is an object of the present invention to provide a connecting device of the above-mentioned type which is comparatively simple and inexpensive to produce using the simplest possible components.

The connecting device connects to at least one external electrical conductor of a photovoltaic solar module. The connecting device includes a plurality of busbars, a support element, a housing, a diode and a contact. The plurality of busbars are arranged next to one another and include a first busbar and a second busbar. The support element is attached to the plurality of busbars and includes a bottom face to be positioned on the solar module. The housing is positioned over the support element and the plurality of busbars and includes an edge surrounding the support element and the busbars when the overhousing is positioned on the solar module. The diode is fitted onto the plurality of busbars and includes diode leads that fit onto one of the plurality of busbars, such that the first and second busbars are connected together via the diode. The contact is positioned with the first busbar for connection with a first contact zone of the first busbar and for connection with the external electrical conductor.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

With respect toFIG. 1, a photovoltaic solar module is shown provided with a connecting device in the form of a junction box or connecting box. The solar module100includes a multilayer arrangement with a flat first layer101on the light-exposed side, which may take the form of a glass sheet or a film-type layer. Furthermore, the solar module100includes a flat second layer103remote from the light-exposed side, which may likewise take the form of a glass sheet or a film-type layer. In the embodiment shown, layers101and103take the form of respective glass sheets. Between the two layers101and103there is located at least one solar cell102or an arrangement of a plurality of solar cells102, which supply electricity by means of a photovoltaic effect when exposed to light. The solar cell(s)102is/are connected to an electrical connection system104. The latter is indicated purely schematically inFIG. 1and serves in particular to interconnect the solar cell(s) electrically and to connect them to the outside world. The electrical connection system104includes for example a copper foil, which is on the one hand electrically contacted with the back of the solar cell(s)102and on the other hand develops into one or more electrical conductors3of the solar module or is connected to at least one electrical conductor3of the solar module, which takes the form for example of a connecting foil or of a connecting tape. By means of such a foil conductor3, the electrical connection system104of the solar module100may be connected to an external connecting lead2, for example in the form of a solar connecting cable.

As is also illustrated inFIG. 1, a connecting device200,300or400, as explained below in more detail, is attached to the back of the layer103, which forms an outer surface of the solar module, for example by adhesive bonding of a housing edge15or65(cf.FIGS. 2 to 19) by means of adhesive107. Furthermore, the layer103includes a lead-through opening105, through which the electrical conductor3, for instance in the form of a foil conductor may be passed to the connecting device.

With respect toFIG. 2, a connecting device200according to the invention is shown, having two main components, namely by a functional unit5and a housing10, which is fitted over the functional unit5. To this end, the housing10includes an edge15around it, which may be arranged on the solar module100by being placed thereon and may be sealingly connected to the solar module. For this purpose, the lower bearing surface of the edge15of the housing10has a substantially flat surface, which is suitable for placing on the likewise flat solar module100and may accordingly be secured. The surrounding edge15is connected by way of a vertical housing wall14, which forms the four side walls of the housing10, to a plate-shaped horizontal housing wall13, which is arranged substantially parallel to the solar module when the housing10is fitted to the solar module. In one of the side walls of the vertical housing wall14, inFIGS. 2 and 3, two connection bushings11are positioned in the side wall pointing to the front, which are provided with respective plug-and-socket connecting devices19for connecting the connecting cable2(not shown inFIGS. 2 and 3) to electrically conductive parts within the housing10.

The functional unit5arranged in the housing10here includes four busbars21to24, as will be explained in greater detail below. The arrangement of the busbars21to24is to be regarded as an example and may also vary as required. In particular, the number of busbars used may vary as required. In the embodiment shown, the outer two busbars21and24include a respective contact zone, which may be connected to an external conductor. The outer two busbars21and24may be connected to respective connecting cables2by way of the connection bushings11arranged on the housing10. The two busbars22and23located in the middle are connected in their end regions merely with a corresponding foil conductor of the solar module connection system. In this context, it is possible for the busbars21and24and the connection bushings11to be arranged in the middle of the housing10, while the busbars22and23may be arranged in the right and left-hand peripheral areas of the housing10. In other embodiments, it is possible, if needed and as required, for just two of the busbars21to24to be provided in the housing10, to form a functional unit5. The busbars21to24are held on a support element40, which includes a bottom face41, by way of which the support element may be arranged on the solar module100by being placed thereon.

Production of a connecting device200according to the invention, as shown inFIG. 2, will be explained in greater detail below with reference toFIGS. 4 to 7.

As is clear in greater detail fromFIG. 4, firstly a support element40is provided, which comprises a substantially flat bottom face41, such that the support element40may be placed by way of the bottom face41on the solar module100, which is likewise of substantially flat construction. On the support element40there are provided supports42for the busbars21to24, and supports44for the diodes31to33, which are connected to the busbars21to24. The support element40is thus constructed in such a way that the individual busbars21to24may be placed in an individually assembleable manner on the support element. The busbars21to24are placed onto the respective supports42and may be fixed to the support element40by a respective locking element43. One or more locking elements43per busbar may be provided for this purpose. The bottom face41is positioned on the underside of a base plate45, on which the supports43and44are arranged.

As is further described with reference toFIG. 5, the current-carrying parts take the form of substantially identically and/or simply configured busbars21to24, which have been shaped and optionally bent, for example, from a metal strip. These busbars21to24are assembled individually on the support element40. To this end, explained for example with reference to the busbar21, the latter is placed onto the corresponding supports42and locked by means of the locking element43in the front and rear areas of the busbar21. The locking element43may take the form for example of a plastics lug or the like, which is softened by thermal contact with a heating element and deformed into a mushroom shape, for example (so-called “hot staking”). Alternatively, it is also possible for the busbars to be snap-fitted to the respective locking element43or fastened in some other way.

As is further illustrated inFIG. 6, the first busbar21includes a first contact zone51for connection with an external electrical conductor, for example of a connecting cable2, as explained above, and a second contact zone52, which is provided for connection with the electrical connection system of the solar module or with the foil conductor3thereof. In the embodiment shown, the busbar21is bent upwards in the second contact zone52, such that a foil conductor of the electrical connection system of the solar module, which leads out of the multilayer arrangement of the solar module, may be applied to the upwardly bent portion within the contact zone52. As described with reference toFIG. 7, a foil conductor or the like is applied to the upwardly bent portion within the contact zone52and secured to a spring element56, which here takes the form of an Ω spring. The foil conductor of the connection system is not shown inFIGS. 6 and 7.

In addition, in the embodiment shown, the busbar21is extended and modified on one side in the contact zone51in such a way that contacting (plugging in and disconnection) is possible with a cable-side contact element. In the present embodiment the contact zone51of the busbar21comprises a mating contact53, which may be connected to a contact element on the housing10or on a cable2, as explained in greater detail below. The mating contact53takes the form in the present embodiment of a U-shaped contact, into which a corresponding pin contact may be introduced in the horizontal or vertical direction. The above explanations regarding the busbar21also apply in similar manner to the busbar24, which is connected to an electrical conductor of a second connecting cable2.

In addition to the busbar21, a second busbar22is arranged substantially parallel to the first busbar21, the busbar includes a contact zone52for connection with a foil conductor3of the electrical connection system of the solar module. A diode31includes diode leads35, which are fitted in each case to one of the busbars21,22and are electrically connected to the respective busbar. In particular, one of the diode leads35is applied to the busbar21and connected electrically thereto, while the other opposing diode lead35of the diode31is applied to the second busbar22and electrically connected thereto. Thus, the first and second busbars21,22are electrically connected together by way of the diode31. In addition to the busbar22, a third busbar23and a fourth busbar24are each arranged substantially parallel to the busbars21and22. Further diodes32and33are provided in a similar manner to the diode31, which further diodes32and33are fitted with their respective diode leads35in each case to one of the busbars22to24and are electrically connected to the respective busbar. For instance, the diode32connects the busbars22and23together, while the diode33connects the busbars23and24together. In the embodiment shown, the diodes31to33take the form of round diodes, the respective diode body36being arranged between the busbars in each case connected together and extending in a space-saving manner in each case below and above the busbars. With the design described, a space-saving arrangement of the busbars and diodes may be achieved.

The diodes31to33and the busbars21to24are arranged in such a way that the respective diode leads35lead substantially straight out of the respective diode31to33and are also connected in this straight led-out manner to the respective busbar. The respective diode leads are inserted for example into correspondingly provided contact portions, for example in the form of grooves, and connected by welding or crimping to the respective busbar. According to the embodiment shown, it is not necessary to bend the diode leads for contacting with the respective busbars, for example in order to be inserted vertically into a respective busbar. Instead, the respective diodes may be simply inserted as delivered into a respective contact portion with straight diode leads and connected to the corresponding busbar. Through this arrangement and through the arrangement of the diode bodies36between the respective busbars21to24, these current-carrying parts are arranged in an overall space-saving manner, such that the space taken up by the current-carrying parts may be reduced in the connector housing of the connecting device. In the embodiment according toFIGS. 6 and 7, the diodes31to33are extend lengthwise across the busbars21to24, the respective diode body36being arranged between the corresponding busbars.

The functional unit5shown inFIG. 7, which is delivered as is for example by a manufacturer of the connecting device (with or without an Ω spring56), may be positioned with the support element40on a solar module. For positioning of the housing10over the functional unit5, additional guide elements or centring elements may be provided, which are not shown in any greater detail inFIG. 7. Alternatively, it is also possible for the diodes firstly to be welded to the busbars and for the resultant, preassembled unit then to be positioned on the support element40, for example clipped therein or attached thereto by heat-shaping. To attach the support element40to the solar module, according an embodiment of the invention, an adhesive component may be provided, for fixing the support element40to a certain degree to the solar module. For example, a double-sided adhesive tape may be used as the adhesive component.

As is additionally shown inFIG. 8, contacts54are held in the housing10on a fastening element. In the embodiment shown, the fastening element takes the form of the horizontal housing wall13of the housing10or a corresponding other shaped portion on the housing10. The contacts54, shown here, are bent, in order to be contacted with the mating contact53on the functional unit5. In another embodiment, it may be preferred, however, for the contacts54to take the form of straight pin contacts, which are pressed from above into the respective U-shaped mating contact53when the housing10is placed onto the solar module, such that they extend horizontally away from the busbars21and24in the direction of the respective connecting cable. When the housing10is placed onto the solar module, the functional unit5together with the support element40and busbars21to24are positioned in the opening12of the housing10, such that in this position the edge15surrounds the support element40and the busbars21to24. As described, in this production step the contacts54integrated in the housing10, which may be straight or bent, are electrically connected to the respective busbar21or24. The other ends of these contacts54project into the external plug-in connection of the plug-and-socket connecting device19(as illustrated schematically inFIG. 2), which for example accommodates, locks in place and contacts a corresponding cable plug on the connecting cable2.

Prior to positioning of the housing10onto the solar module, the edge15thereof is provided, on its underside and optionally on further relevant surfaces of the housing coming into contact with the solar module, with a suitable adhesive component or sealing component (cf. adhesive107according toFIG. 1), in particular a silicone-based sealing glue. After curing of the adhesive on the underside of the edge15after positioning of the housing10on the solar module, the electrically conductive parts inside the housing10are largely hermetically shielded against environmental influences and secured against being touched. Due to pre-fixing of the support element40on the solar module, for example by way of double-sided adhesive tape, the solar module with fitted connecting device200may in principle be stored and transported immediately even in a vertical position, since in this case the support element40assumes the pre-fixing function until the sealing glue applied to the edge15is appropriately cured. The adhesive component positioned on the support element40should here exhibit such an adhesive force that at least the intrinsic weight of the connecting device200may be supported. As soon as curing has taken place, the housing10may fully assume its protective function and also absorb mechanical forces, which may possibly act on the connecting device200as a result of pulling on the connecting cable2.

With respect toFIG. 9, another connecting device300according to the invention is shown, which largely corresponds to the structure of the connecting device200, as explained above with reference toFIGS. 2 to 8. In particular, the functional unit5, which is arranged in the interior of the housing10, corresponds to the functional unit5of the connecting device200according toFIGS. 2 to 8. Unlike the connecting device200, the connecting device300comprises connection bushings17for the connecting cable2which differ from the connection bushings11as explained with reference toFIGS. 2 and 3. The connection bushings17are here configured in such a way that the connecting cable2may be attached to the housing10by means of a cable gland or another type of cable fastening. In the embodiment shown, the connection bushings17include a corresponding external thread, to which a respective cable gland18may be fitted, in order to connect a respective connecting cable2to the housing10.

As is also shown inFIG. 10, the connecting cable2is fitted to the housing10before the housing10is positioned over the support element40and placed onto the solar module. In the embodiment shown, a contact54is arranged on an electrical conductor of the respective connecting cable2, as shown in greater detail with reference toFIG. 11. When the housing10is placed onto the solar module, the respective contact54, which may be bent or straight, is positioned from above into the corresponding mating contact53on the functional unit5. This is performed in a similar manner to the connecting device200according toFIGS. 2 to 8.

FIG. 12shows another embodiment, according to which the cable2together with the fitted contacts54is subsequently introduced through the connection bushings17into the housing10, in order to be connected to the corresponding mating contact53of the functional unit5. The contacts54in each case take the form of straight pin contacts, which are introduced horizontally into the respective mating contact53. The variants of the contacts53and54as U-shaped contacts or pin contacts should be regarded merely as examples, which may be possible to provide any other type of plug-and-socket connection in this location. This also applies in a similar manner to the other embodiments of the connecting devices200,300or400. After introduction of the connecting cable2into the respective connection bushing17, the connecting cables2are fixed on the housing10using corresponding cable glands, wherein the cable glands18according toFIGS. 9 and 10may be used as cable glands.

With respect toFIG. 13, another connecting device400according to the invention is shown, where in a similar manner to the embodiments of connecting devices200and300, as described above, two individually assembled busbars21to24are used, which are of identical or in principle similar construction to the busbars21to24of the connecting devices200and300. In contrast, the support element70of the connecting device400is of different construction. In the embodiment shown, the support element70is formed of a plastics housing72, which encloses at least part of the busbars21to24and at least one diode, which connects two busbars together electrically, so forming a functional unit5. If a plurality of busbars and a plurality of diodes are provided, the plastics housing accordingly encloses part of these busbars and the entirety of the diodes. With regard to the construction of the individual busbars21to24and the diodes31to33, reference is made to the explanations provided in relation toFIGS. 2 to 8.

With reference toFIGS. 15 to 18, manufacturing of a connecting device400, according to the invention is explained in greater detail.

The individual busbars21and24are positioned substantially parallel to one another in a suitable tool and connected to the diodes31to33, as shown inFIG. 16. The current-carrying parts arranged in this way are then encapsulated with plastics material by injection moulding or potting, such that at least part of the busbars21to24and the diodes31to33are surrounded by a housing72formed of the plastics material, so forming a functional unit5. In this way, a support element70is formed which includes on its underside a bottom face71, which serves as a bearing surface by way of which the support element70is placed onto the solar module. The diodes31to33arranged in a row next to one another are surrounded by the plastics housing72, which lengthwise surrounds the diodes31to33and which extends lengthwise across the busbars21to24. The plastics housing72may in principle adopt any suitable shape, for example it may also extend upwards between the busbars21to24, such that the insulation distances between the busbars may be further reduced. Encapsulation by injection moulding or potting of the pre-assembled, current-carrying arrangement illustrated inFIG. 16, results in a compact functional unit5, as shown inFIG. 17, which is comparatively simple to handle and displays a degree of mechanical stability. In this way, the functional unit5may be positioned in the housing60without risk of damage. The unit formed by the plastics housing72may in principle be replaced as a whole when servicing is required, i.e. in the event of failure of one or more of the diodes31to33. This simplifies handling from the user's standpoint, in that only simply configured components have to be replaced.

In the case of partial shading of a solar installation, the bypass diodes31to33are activated, which may under certain circumstances become very hot. Encapsulation of the current-carrying components by injection moulding or potting to form a housing block, so forming the functional unit5, results in improved heat dissipation, which has an overall positive effect on the performance of the connecting device. It is additionally possible to achieve the maximum possible degree of automation of parts manufacture, assembly and handling on the part of the user whilst maintaining the existing standard.

FIG. 19shows the underside of a housing60, in the opening62of which the functional unit5according toFIG. 18is arranged. In a similar manner to the housing10of the connecting device200, the housing60comprises a horizontal housing wall63and a vertical housing wall64, which in the form of side walls joins the edge65surrounding the housing60to the horizontal housing wall63. In addition, connection bushings61are provided on the housing60, which are identical in construction to the connection bushings11of the connecting device200. Contacts54are accordingly arranged in the housing60, which contacts54make contact with a respective mating contact53on the functional unit5when the housing60is positioned over the functional unit5onto the solar module. In this context, reference is made to the explanations made above in relation to the connecting devices200and300.

In relation to the heat to be dissipated from the diodes, in the embodiment shown, the plastics housing72of the functional unit5includes at least one well76, which comes into contact with a corresponding raised portion66on the inside of the housing60, more precisely on the inside of the horizontal housing wall63of the housing60, as is clear from viewingFIGS. 17 to 19together. The wells76and raised portions66assist in improved heat dissipation to the outside of the connector housing. To achieve improved heat dissipation, the wells76in the plastics housing72are positioned as close as possible to the heat source. The wells76are shown symbolically, in the shown embodiment, by funnels. The housing surface of the plastics housing72is also enlarged, such that heat dissipation may be increased by an enlarged transitional surface. The raised portions66positioned on the inside of the housing60correspond in extent and diameter to the wells76. It is also possible, instead of the wells76to provide corresponding raised portions on the plastics housing72, which correspond with corresponding wells on the inside of the housing60.

This improved heat dissipation may be additionally promoted by providing the plastics housing72with at least one well or raised portion76,66, which comes into contact54respectively with a corresponding raised portion or well66,76on the inside of the housing60. In particular, the well or raised portion76,66is formed on the plastics housing72in such a way that heat developed within the plastics housing72is at least partly dissipated via the well or raised portion76,66on the plastics housing72to the corresponding raised portion or well66,76on the housing60. The well or raised portion76,66on the plastics housing72may as far as possible be provided in the vicinity of the heat source and takes the form, for example, of a funnel or the like. In this way, the housing surface of the plastics housing72is also enlarged, whereby the quantity of heat dissipated by the plastics housing72may be increased. The wells76, for example in the form of funnels, in the plastics housing72or the corresponding raised portions66may also assume a guiding and centring function upon final assembly of the connecting device, to the effect that they allow perfectly fitting serving up and fastening of the housing60relative to the support element, such that functional unit5and housing60are correctly oriented one relative to the other.

The wells76may, together with the raised portions66on the housing60, also assume a guiding and centring function upon final assembly of the connecting device400, wherein they allow perfectly fitting serving up and fastening of the housing60. In this production process, the integral contacts54are also electrically connected to the corresponding mating contacts on the busbars21and24of the functional unit5. The other ends of these contacts project in turn into an external plug-in connection, by means of which a corresponding connecting cable plug may be contacted, received, and locked in place. The housing60is fastened to a solar module in the same way as already explained above with reference to the housing10of the connecting devices200and300. With regard to different cable connection variants, all embodiments which have already been described in relation to the embodiments ofFIGS. 2 to 12are here also conceivable.

Prior to positioning of the housing60, the foil conductors of the connection system of the solar module are attached to the respective busbars21to24. To this end, Ω springs56are for example used, as shown inFIG. 17, which are fitted onto the respective busbars21to24. The foil conductors are connected detachably to the busbars. Detachable connection of the foil conductors may be effected by the user, for example in an automatable step by means of the Ω springs56. The foil conductors may however also be fixedly contacted with the respective busbars21to24by soldering or welding. In this context, the invention offers the advantage that the foil conductors may be connected to the functional unit5or the busbars21to24in a situation in which the functional unit5is very readily accessible. This is a consequence of the fact that the functional unit5has not yet been arranged in a surrounding connector housing, but rather has merely been pre-fixed on the solar module by way of the underside of the support element40or70. In this situation, the functional unit5is very readily accessible from all sides, such that the current-carrying parts may be contacted appropriately rapidly and easily. Upon fitting of the housing10or60, rapid and reliable contact is again brought about on the cable connection side and in the same step a hermetic seal is achieved between the current-carrying parts and external environmental influences. If the connecting cable has already been fitted on the housing, assembly is concluded at this point. Otherwise, a connecting cable may be fastened to the housing by simple plug-in connection and connected to the current-carrying parts arranged therein.

Advantages of the invention are thus significantly reduced costs for producing a connecting device compared with the connection methods described in the introduction. Moreover, the number of components is reduced and the components are simplified, as are the steps for assembly thereof In addition, the connecting device is structurally simplified, and savings are made in material and assembly costs.

The invention thus offers the advantage that it is possible with such a connecting device to achieve a marked reduction in costs relative to conventional connecting devices. This is achieved in particular in that the connecting device according to the invention results in smaller dimensions and consequent savings in material. In addition, it is possible to use fewer and nevertheless simpler components, resulting, moreover, in the maximum possible level of automation in parts manufacture and assembly. The invention additionally makes it possible for a handling method modified from previously known methods to be performed automatically on the premises of the user of the connecting device.