PHOTOVOLTAIC MODULE AND CONNECTION ARRANGEMENT FOR A PHOTOVOLTAIC MODULE

Description

[0001] The invention relates to a connection arrangement for a photovoltaic module (PV module) comprising at least one cell arrangement that can be externally connected via at least two contacts. The connection arrangement includes at least one bypass diode, which is arranged externally from the at least one cell arrangement and connected in parallel to the at least one cell arrangement. The connection arrangement comprises at least one junction box and at least one plug-in socket into which the bypass diode is inserted with plug-in contacts. The invention further relates to a photovoltaic module with such a connection arrangement.

[0002] Photovoltaic modules, for example for mounting on a house roof or in ground-mounted systems, typically have a number of photovoltaic cells (PV cells) connected in series and / or parallel to form at least one cell array that can be contacted externally via connecting cables. Often, PV modules have several such cell arrays connected in series within the module. In In this case, each cell array is typically led out of the module with its terminals, allowing a so-called "bypass diode" to be connected in parallel to each array. The bypass diodes divert current around shaded or defective cell arrays. Without the bypass diodes, shading or a defect in one of the module's cell arrays would reduce the current flow through the entire module, even if the other cell arrays in the module, or even other modules connected in series with it, are neither shaded nor defective.

[0003] Prior art describes PV modules in which the terminals of the existing cell arrays (usually three cell arrays) are located adjacent to each other on the rear side of the PV module and can be connected in a common terminal area. These contacts can be, for example, non-insulated contact strips on the rear side of the PV module, which is otherwise covered by an insulating layer. A junction box is placed over this terminal area, for example, glued on, and bypass diodes are located inside this junction box, making contact with the terminals of the PV module. Two connecting cables also lead to this junction box, connecting to the outer contacts of the series-connected cell arrays, and through which the PV module is externally connected.

[0004] A PV module with such a connection arrangement is described, for example, in an embodiment in publication US 2016 / 0141435 A1. InIn another embodiment, the publication describes a PV module in which contact surfaces of different cell arrangements are not positioned in a common connection area on the back of the PV module, but at several different positions. In In this case, each of the connection areas is covered with a socket that accommodates a bypass diode. At least two of the sockets function as junction boxes, as described previously, with a connection cable for the external connection of the PV module leading to these sockets and being connected to one of the cell arrays inside the socket. In In another embodiment, it is described that the bypass diodes can also be integrated into the PV module, specifically into the layer stack of the PV module.

[0005] Shading of individual cell arrays combined with high solar irradiance on neighboring cell arrays can lead to unfavorable operating conditions for the associated bypass diodes, resulting in high currents and high temperatures. Such operating conditions, as well as aging processes, can lead to a bypass diode failure. While a bypass diode could theoretically be replaced as long as it is not integrated into the layer stack of a PV module, users and sometimes even installers of PV modules typically lack the necessary knowledge and tools.

[0006] German patent application DE 10 2015 111 768 A1 discloses a connection arrangement for such a PV module, in which a plug socket is arranged on a junction box into which a bypass diode with a corresponding connector can be inserted. This allows the bypass diode to be conveniently removed for inspection and easily replaced if defective. German patent application DE 10 2015 218 526 A1 describes a connection arrangement for a PV module with a plug socket into which a connector can be inserted. In this arrangement, a bypass diode is replaceably integrated into the connector, which also offers the advantage of easy inspection and, if necessary, replacement of the bypass diode. However, both systems require appropriately designed junction boxes or connectors.

[0007] It is an object of the present invention to provide a connection arrangement for a PV module and a PV module with a connection arrangement in which problems due to defective bypass diodes can be easily rectified even by non-expert persons, without having to use specially designed junction boxes with possibly special connectors.

[0008] This problem is solved by a connection arrangement for a PV module or a PV module with such a connection arrangement having the features of independent claim 1. Advantageous embodiments and further developments are the subject of the dependent claims.

[0009] A connection arrangement according to the invention of the type mentioned above is characterized in that at least one connecting cable is connected to the at least one connection box, which leads to a further connection box of the photovoltaic module, wherein a plug holder is looped into the at least one connecting cable and wherein the plug holder has the at least one plug receptacle into which the at least one bypass diode is inserted.

[0010] The plug-in socket, together with the pluggable bypass diode, offers a simple way to replace the bypass diode if it has become inoperative due to, for example, thermal and / or electrical overload. Thanks to the simple plug-in mechanism, even untrained personnel can perform the replacement. Furthermore, it is possible to remove a bypass diode and easily test its functionality, which is only possible with more complex testing procedures when the bypass diode is integrated into the terminal assembly. The pluggable bypass diode also allows for flexible configuration or retrofitting of the terminal assembly with bypass diodes of varying quality levels. For example, the manufacturer's initial silicon bypass diodes can be replaced with actively switched bypass diodes based on MOSFET transistors to minimize losses during shading conditions.

[0011] In an advantageous embodiment, the connection arrangement comprises at least one junction box. A connection cable for the photovoltaic module can be connected to the junction box. The junction box can have a contact element that can be connected to contacts of the photovoltaic module. The contacts of the PV module can, for example, be exposed contact strips on the back of the PV module. In this case, the contact element is soldered or welded to the contact strip, for example, by spot welding. A spring contact, in particular a double spring contact, can also be used. The contacts of the PV module can also be (protruding) connection contacts that are already applied to exposed contact strips. In this case, the contact element of the junction box can, for example, be a tulip contact or another type of plug-in contact.Even a (protruding) connection contact can be contacted via a spring contact or a welded or soldered contact.

[0012] In a further preferred embodiment, the junction box can have an insulation-penetrating contact for connection to the connecting cable and / or the connecting cable. This allows for a simple and space-saving connection to the cables. In alternative embodiments, a connection can also be made by crimping, soldering, welding, or stapling, with the cable end being stripped in each case.

[0013] In one embodiment, the at least one junction box can also have at least one socket into which a bypass diode is inserted. If multiple junction boxes are present, each can, for example, accommodate one socket. Multiple sockets for several bypass diodes can also be provided for a single junction box, possibly even for all existing bypass diodes, especially if there is only one junction box on the PV module. Preferably, at least part of the surface of the bypass diode is located outside the junction box. This makes the bypass diode easily accessible and allows it to be replaced without having to open the junction box. Furthermore, the bypass diode being at least partially located outside the junction box has the advantage of avoiding or at least reducing direct heat transfer into the PV module. This prevents a degradation of the PV module's performance due to thermal input from the bypass diode.reduced.

[0014] In a further advantageous embodiment of the connection arrangement, the at least one bypass diode is housed in a casing from which the plug contacts protrude. The casing, preferably made of an insulating material, serves as a gripping area, allowing the bypass diode to be safely grasped and inserted into or removed from the socket. The casing can also be mechanically encoded to ensure that the bypass diode can only be inserted with the correct polarity. Finally, the casing facilitates efficient heat dissipation from the bypass diode to the surrounding environment, as it has a larger surface area than the bypass diode itself. This is particularly beneficial if the at least one bypass diode is advantageously surrounded within the casing by a highly thermally conductive potting compound, such as a plastic compound.

[0015] InIn a further advantageous embodiment of the connection arrangement, a light-emitting diode (LED) is connected in parallel to at least one bypass diode. If the bypass diode is defective, a voltage drop across the bypass diode causes the LED to light up, thus signaling the defect.

[0016] The LED can be arranged together with the bypass diode, for example in a common housing that can be transparent or partially transparent, so that a defect signaled by the LED is easily visible from the outside. Alternatively, the bypass diode can be overmolded with a transparent material. It is also possible to position the LED in the area of ​​the connector.

[0017] In a PV module according to the invention, bypass diodes are easily replaceable due to the use of such a connection arrangement. This results in the advantages mentioned in connection with the connection arrangement.

[0018] The invention is explained in more detail below with reference to an exemplary embodiment and the accompanying figures. The figures show: Figure 1a is an isometric view of a PV module looking at its back; Figure 1b is a detailed view of part of a connection arrangement of the PV module. Figure 1a Figure 1 is a detailed view of a diode arrangement of the PV module of Figure 1a; Figure 2 is a detailed view of part of a connection arrangement of a further embodiment of a PV module; Figure 3a is an isometric view of a diode unit for use with a PV module; and Figure 4a is an isometric view of a diode unit without a housing.

[0019] In Figure 1aFirst, a PV module 1 is shown in an isometric representation. The PV module 1 has a frame 2 and the actual module structure, which in this application is also referred to as layer structure or layer stack. This module structure is shown in the representation of the Figure 1a Only one reverse side 3 is recognizable.

[0020] In PV module 1, the module structure comprises one or more cell arrays—specifically three in this case—each containing a plurality of PV cells (not individually identifiable here). These cells are interconnected at their electrodes on the rear side 3, for example, via conductive traces. The rear side 3 is covered with an insulating layer, which is interrupted at selected points to expose the electrodes or the conductive traces connecting them and to allow for contact. Alternatively, connecting tabs or contacts may be present, which are connected to the electrodes or the conductive traces and protrude from the insulating layer.

[0021] At the in Figure 1aIn the illustrated embodiment, the PV module 1 is contacted at four points. A junction box 4 is mounted, preferably glued, over each contact point. Two adjacent contact points or junction boxes 4 are assigned to each cell arrangement of the PV module. For example, a first cell arrangement can be contacted via the two leftmost junction boxes 4, a second cell arrangement via the two middle junction boxes 4, and a third cell arrangement via the two rightmost junction boxes 4. It should be noted that the number of three cell arrangements connected in series in the illustrated embodiment is purely exemplary. The connection arrangement presented in this application can be used for any number of cell arrangements connected in series. The individual cell arrangements themselves typically have...a plurality of cells connected in series and / or in parallel.

[0022] From each of the two outermost connection boxes 4, a connecting cable 5 leads outwards. This connecting cable 5 is shown in a shortened form in the figures. In In one implementation, this connecting cable 5 is longer and has a connector at each end, with which a connection to an adjacent module or a module connection box or similar can be established.

[0023] A connecting cable 6 is arranged between each pair of the connection boxes 4, into which a diode arrangement 10 is inserted. The diode arrangement 10 is in the Figure 1aShown only schematically. It includes a bypass diode (not visible here) that contacts the two cable sections of the connecting cable 6 with its anode and cathode, respectively. In this case, three bypass diodes are thus connected antiparallel to each of the three cell arrangements of the PV module 1.

[0024] The connection arrangement can preferably be pre-assembled and pre-mounted, so that during final assembly of the PV module 1 it only needs to be placed onto the connection contacts of the PV module 1. Preferably, an adhesive sealant is used with which the connection boxes 4 are sealed to the rear side 3 of the PV module 1.

[0025] For connecting the connection cables 5 and connecting cables 6 within the junction boxes 4, insulation-penetrating contacts can be used, for example. Alternatively, the connection cable 5 can be formed as a single unit with the corresponding section of the connecting cable 6. In this case, the connection cable 5 and this section of the connecting cable 6 form a continuous cable. The same applies to the two sections of the connecting cables 6 in the Figure 1 a shown middle two connection boxes 4.

[0026] In the Figure 1b is part of the connection arrangement of PV module 1 made of Figure 1a A more detailed isometric view is shown. Here it can be seen that the diode assembly 10 includes a plug holder 11 into which the bypass diode can be inserted. The plug holder 11 is in Figure 1c shown again enlarged.

[0027] The plug holder 11 comprises a plug socket 111 into which the bypass diode can be inserted into a plug receptacle 113. A sealing cap 112 is captively connected to the plug socket 111 via a flexible bridge. This sealing cap can be placed on the plug holder 11 with the inserted bypass diode and seals the plug receptacle 113. Figures 1b and 1c Concealed within the socket are 111 contacts which are coupled to the connecting cables 6 and make contact with the inserted bypass diode. The socket 113 and the inserted bypass diode can be shaped such that the bypass diode can only be inserted in one possible orientation to ensure the correct polarity of the inserted bypass diode.

[0028] The plug holder 11, or rather its plug receptacle 123, together with the pluggable bypass diode, offers a simple way to replace the bypass diode if it has become inoperative due to, for example, a thermal and / or electrical overload. Thanks to the simple plug-in mechanism, even untrained personnel can perform the replacement. Furthermore, it is possible to remove a bypass diode and easily test its functionality, which is only possible with more complex measuring procedures when the bypass diode is integrated into the terminal assembly. The pluggable bypass diode also allows for flexible configuration and retrofitting of the terminal assembly with bypass diodes of varying quality grades.For example, bypass diodes initially provided by the manufacturer made of silicon can be replaced by actively switched bypass diodes based on MOSFET transistors in order to minimize losses during a shading situation.

[0029] Figure 2 Figure 1 shows part of a connection arrangement for a PV module (not shown in detail) in a further embodiment. The connection arrangement again includes a junction box 4, which is mounted on the back of the PV module. Two cables lead to the junction box 4; these can be connection cables 5 and / or connecting cables 6.

[0030] In this embodiment, a plug receptacle 41 is formed in the junction box 4 as part of a diode assembly 10. The plug receptacle 41 corresponds to the plug receptacle 113 of the plug holder 11 in that a diode unit 12 with a bypass diode can be inserted. The diode unit 12 is, in this example, Figure 2shown separately from the connection box 4, for example in a state shortly before being plugged into the socket 41.

[0031] The junction box 4 can be positioned above a contact of the PV module, so that inside the junction box 4 the contact of the PV module is connected to the bypass diode and also to the connecting cables 5 or connecting cables 6. Alternatively, the junction box 4 shown can also simply establish a connection between the bypass diode and the cables shown (which in this case are exclusively connecting cables 6). The junction box 4 then corresponds in principle to the connector 11 of the previous embodiment, with the difference that the junction box 4 is mounted on the back of the PV module and is not supported by the connecting cables 6.

[0032] In the diode unit 12, the bypass diode is arranged in a housing 121 and is connected within the housing 121 to plug contacts 122 that protrude from the housing 121. The in Figure 2 The diode unit 12 shown is in Figure 3a also shown in more detail separately. Figure 3b also shows a diode unit 12 with a housing 121 and plug contacts 122, which differs from the one in the Figures 2 and 3a The example shown differs by the shape of its casing 121.

[0033] The housing 121, formed from an insulating material, serves as a gripping area by which the diode unit 12 can be safely grasped and inserted into or removed from the plug receptacle 41 or 113. Mating contacts, which are formed in the terminal box 4 or the plug socket 111 of the plug holder 11 and with which the plug contacts 122 make contact, are recessed so far into a slot in the plug receptacle 41, 113 due to the height of the housing 121 that contact is also prevented here.

[0034] In the Figures 2 and 3aThe housing 121 shown advantageously has lateral recesses that allow the diode unit 12 to be pulled out of the socket 41 or 113. If necessary, a pliers- or tweezer-like tool can be used for this purpose. In the lower area of ​​the housing 121, facing the plug contacts 122, a ridge is also formed, which serves to seal the housing 121 in a slot of the socket 41, 113.

[0035] A possible internal structure of the diode units 12 of the Figures 3a and 3b is in the Figures 4a and 4b shown. In the Figures 4a and 4b The diode unit 12 is shown without the housing 121.

[0036] Each diode unit 12 includes a bypass diode 123, which is soldered to the plug contacts 122 via connecting elements. The bypass diodes 123 are surface-mount devices. In alternative configurations, leaded bypass diodes can be used instead, with their leads connected to the plug contacts 122.

[0037] The unit consisting of bypass diode 123 and plug contacts 122 is preferably inserted into the housing 121 and potted there with potting compound. This ensures good heat transfer from the bypass diode 123 to the housing 121, from which the heat can be efficiently dissipated to the environment due to the larger surface area of ​​the housing 121 compared to the surface area of ​​the bypass diode 123 itself. In In one embodiment of the diode unit 12, the potting compound itself forms the housing 121.

[0038] The diode unit 12 of the example of the Figure 4bunlike, for example, the Figure 4aAdditionally, a light-emitting diode (LED) 124 is connected in parallel to the bypass diode 123 and is also connected to the plug contacts 122. Preferably, the LED 124 is internally equipped with a series resistor, or a series resistor is connected in series, so that the current flowing through the LED 124 is limited. If the bypass diode 123 is functioning correctly, the voltage drop across the bypass diode 123 when current flows through the diode assembly 12 is smaller than what is required for the LED 124 to light up. If, on the other hand, the bypass diode 123 is defective in such a way that it does not accept current even in the forward direction, the voltage drop across the plug contacts 122 becomes so large that the LED 124 lights up, thus signaling the defect of the bypass diode 123. In order to be able to see the LED 124 from the outside, the housing 121 is at least transparent in this area or is provided with a transparent viewing window.If a potting compound is used, it should be equally transparent or cover the surface. LED 124 not.

[0039] In Alternative configurations of the connection arrangement may provide for the positioning of such a light-emitting diode not in the diode unit 12, but within the plug holder 11 or the junction box 4 into which the diode unit 12 is plugged. Reference sign

[0040] 1 Photovoltaic module (PV module) 2 Frame 3 Back 4 Junction box 41 Connector 5 Connection cable 6 Connecting cable 10 Diode assembly 11 Connector holder 111 Socket 112 Sealing cap 113 Connector 12 Diode unit 121 Housing 122 Connector contact 123 Bypass diode 124 Light-emitting diode (LED)

Claims

1. A connection arrangement for a photovoltaic module (1) which has at least one cell arrangement which is externally contactable to at least two contacts, having at least one bypass diode (123), which is arranged externally of the at least one cell arrangement and connected in parallel to the at least one cell arrangement, wherein the connection arrangement comprises at least one plug receptacle (41, 113) into which the bypass diode (123) can be plugged in with plug contacts (122), and at least one connection box (4), characterized in that at least one connection cable (6) is connected to the at least one connection box (4), which leads to a further connection box (4) of the photovoltaic module (1), wherein a plug holder (11) is countersunk into the at least one connection cable (6) and wherein the plug holder (11) has the at least one plug receptacle (113) into which the at least one bypass diode (123) is plugged.

2. The connection arrangement according to Claim 1, in which at least one power cable (5) for the photovoltaic module (1) is connected to at the at least one connection box (4).

3. The connection arrangement according to Claim 1 or 2, in which the at least one connection box (4) in each case has a contact element that can be connected to contacts of the photovoltaic module (1).

4. The connection arrangement according to any one of Claims 1 to 3, in which the connection box (4) has an isolation-penetrating contact for connection to the power cable (5) and / or the connection cable (6).

5. The connection arrangement according to any one of Claims 1 to 4, in which the at least one bypass diode (123) is received in a housing (121), out of which the plug contacts (122) protrude.

6. The connection arrangement according to Claim 5, in which the at least one bypass diode (123) in the housing (121) is surrounded by a grouting compound.

7. The connection arrangement according to any one of Claims 1 to 6, in which a light-emitting diode (124) is connected in parallel to the at least one bypass diode (123).

8. The connection arrangement according to Claim 5 and 7, in which the light-emitting diode (124) is likewise arranged in the housing (121).

9. A photovoltaic module (1) with at least one connection arrangement according to any one of Claims 1 to 8.