Photovoltaic module with a junction box and junction box for a photovoltaic module

Abstract

Photovoltaic module (1) with at least one connection contact (5) and at least one junction box (11) arranged on a rear side (3) of the photovoltaic module (1) and having a housing (111) which has at least one opening (115) towards the rear side (3) for the passage of the at least one connection contact, characterized in that an adhesive (21) for fixing and / or sealing is provided between the at least one junction box (11) and the rear side (3) of the PV module (1) and that a cavity (114) is provided inside the junction box (11) for fastening the junction box (11), which extends from the opening (115) to the rear side (3) of the PV module (1), widens towards the rear side (3) and is filled with a potting compound.

Description

[0001] The invention relates to a photovoltaic module with at least one connection contact and at least one junction box arranged on a rear side of the photovoltaic module and having a housing that has at least one opening toward the rear side for the passage of the at least one connection contact. The invention further relates to a junction box with a housing that has at least one opening toward a bottom side for the passage of at least one connection contact of a photovoltaic module.

[0002] Photovoltaic modules, hereinafter also abbreviated as PV modules, e.g. for installation on a house roof or in open-air systems, usually have a plurality of photovoltaic cells (PV cells) which, when connected in series and / or parallel, form at least one cell arrangement which can be contacted externally via connecting cables. The PV modules themselves usually have a supporting glass or plastic pane which, on the side facing away from the sun, is provided with a photovoltaically active layer stack. On the rear side facing away from the sun, the layer stack is usually covered by a sealing and protective rear cover layer. Connection contacts, e.g. in the form of conductive, metallic strips, usually copper strips, emerge from this cover layer. The connection contacts are connected in the junction boxes mentioned above with connection cables which, for further cabling, are provided with connectors at their free ends.

[0003] The junction boxes thus serve to protect and mechanically secure the transition between the connection contacts and the connecting cables. Therefore, the junction boxes must be securely mounted on the back of the PV module and be sealed against at least splash water, both towards the connecting cable and the back of the PV module.

[0004] A common and established approach is to provide the junction box with an adhesive surface on its underside. A gap-filling adhesive is applied to this surface before the junction box is placed on the module. Once cured, this adhesive adheres and seals the junction box to the back of the PV module. A silicone-based two-component adhesive is typically used for this purpose. To ensure secure attachment and sealing, the adhesive surface of the junction box is usually activated beforehand using a complex plasma irradiation process.

[0005] The procedure described is practical, but technically complex and therefore expensive.

[0006] It is an object of the present invention to describe a junction box for a PV module that is less complex and thus more cost-effective and quicker to install. A further object is to describe a PV module with such a junction box.

[0007] This object is achieved by a junction box or a PV module with a junction box having the respective features of the independent claims. Advantageous embodiments and further developments are the subject of the dependent claims.

[0008] A PV module according to the invention of the type mentioned at the outset is characterized in that an adhesive for fixing and / or sealing is present between the at least one junction box and the rear side of the PV module and in that a cavity is present within the junction box for fastening the junction box, which cavity extends from the opening to the rear side of the PV module and widens towards the rear side and is filled with a casting compound.

[0009] A junction box according to the invention for a PV module of the type mentioned at the outset is characterized in that a cavity widening towards the underside extends in the housing from the opening for the at least one connection contact.

[0010] Instead of fastening using an adhesive, which performs both sealing and fastening and requires careful preparation of the adhesive surfaces, the PV module or junction box according to the invention only uses an adhesive with which the junction box is temporarily fixed to the back of the PV module, for example during the assembly process. If, in the further course of assembly, cavities in the junction box are filled with an insulating and corrosion-protecting potting compound, the cavity, which widens towards the back of the PV module according to the invention and is also filled with potting compound, leads to the junction box being fastened to the back. Due to the larger surface area that can be used in this way, special pre-treatment of the surfaces for this type of fastening with the potting compound is not necessary.

[0011] In an advantageous embodiment of the PV module, a permanently elastic adhesive gel, particularly a polyurethane-based gel, can be used as the adhesive. Such a gel is easy to process, has excellent sealing properties, and sufficient adhesion properties to complete the further assembly process until the potting compound cures.

[0012] In a further advantageous embodiment, the cavity of the junction box, which widens toward the underside of the junction box or the back of the PV module, is pyramid-shaped. Such a cavity has sloped surfaces in all spatial directions, which ensure a firm hold in conjunction with the potting compound.

[0013] In a further advantageous embodiment, the junction box has a connection unit, in particular in the form of a stamped grid, for contacting the at least one connection contact and / or a connection cable and / or at least one additional optionally present bypass diode.

[0014] The invention is explained in more detail below using exemplary embodiments and figures. The figures show: Fig. 1 a spatial representation of a PV module without a junction box, looking at its rear side; Fig. 2 a detailed view of a contact area of ​​the PV module of the Fig. 1 with an unassembled connection arrangement; Fig. 3a shows a first embodiment of a connection box of the connection arrangement of Fig. 2 with a view of its underside before applying a gel; Fig. 3b like Fig. 3a, after applying the gel; Fig. 4 like Fig. 2, with the junction box placed on the contact area; Fig. 5 like Fig. 4, with encapsulated and sealed junction box; Fig. 6a shows a connection arrangement with a second embodiment of a junction box, with a view of the underside of the junction box before applying a gel; and Fig. 6b like Fig. 6a, after applying the gel.

[0015] In Fig. 1 shows a PV module 1 in a spatial oblique view. The PV module 1 has a frame 2 and the actual module structure, which in the context of this application is also referred to as a layered structure or layer stack. This module structure is shown in the illustration of Fig. 1 only one back 3 can be seen.

[0016] In the PV module 1, the module structure comprises one or more cell arrangements - specifically two here - each having a plurality of PV cells that are not individually visible here. The PV cells are interconnected within the module structure in the form of at least one string. Several strings can be connected in parallel. The rear side 3 of the PV module 1 is covered with an insulating and protective layer, whereby this insulating and protective layer is interrupted at selected locations to allow the exit of connection contacts 5 of the cell arrangements. In the Fig. In the PV module 1 shown as an example in Figure 1, the two cell arrangements can be contacted separately in each connection contact area 4 via two connection contacts 5 each. The methods and devices according to the invention presented in this application can also be implemented with PV modules with a larger or smaller number of connection contact areas 4 or connection contacts 5. The connection contact areas 4 with the respective connection contacts 5 are shown disproportionately large in this figure for the sake of better visibility.

[0017] In Fig. 2 is an edge area of ​​the PV module 1 of the Fig. 1 is shown enlarged to show one of the connection contact areas 4 in more detail. The two connection contacts 5 terminate in the connection contact area 4 in the form of metallic contact strips, which are usually made of copper. After the module structure has been manufactured, the rear side 3 is initially completely covered by the protective and insulating layer. This is removed in the connection contact areas 4, exposing the initially flat connection contacts 5. In the Fig. 2, the connection contacts 5 have already been bent upwards in order to make them easier to contact in further process steps.

[0018] Further in the Fig. 2 shows a connection assembly 10 that has not yet been assembled. The connection assembly 10 comprises a connection box 11 and a connecting cable 14 extending therefrom, which terminates at its free end in a connector 15.

[0019] The junction box 11 has a housing 111 with an upper part 112 in which a connection unit 12 is arranged. The connection unit 12 serves to connect the connection contacts 5 to the connection cable 14 and a bypass diode 13, which is also arranged in the junction box 11. The connection unit 12 can be manufactured, for example, using a stamped grid, whereby connections to the connection contacts 5, the connection cable 14 and / or the bypass diode 13 can be made by spot welding, soldering, or crimping.

[0020] In the Fig. 3a shows a first embodiment of the junction box 11 with a view of its underside 113. An outer circumferential area of ​​the underside 113 forms a support surface for the junction box 11. With this support surface, the junction box 11 rests on the rear side 3 of the PV module 1 after installation. In a central area of ​​the underside 113, a pyramid-shaped cavity 114 is introduced, which tapers upwards in the figure (i.e., in a direction pointing away from the underside 113) and opens into an opening 115. When the junction box 11 is in place, the connection contacts 5 of a connection contact area 4 protrude through this opening 115 in order to be contacted on the top side of the junction box 11 (not visible here). This will be explained below in connection with Fig. 4 is shown in more detail.

[0021] In the Fig. 3a further shows a connection area 116 into which the connecting cable 14 is inserted into the connection box 11. The connecting cable 14 itself is in this Fig. 3a not shown.

[0022] The Fig. 3a shows an example of an applicator 20 for an adhesive 21. Before the junction box 11 is placed on the back 3 of the PV module, a circumferential bead of the adhesive 21 is applied to the outer edge area of ​​the support surface on the underside 113 of the junction box 11 using the applicator 20, as shown in Fig. 3b is shown.

[0023] The adhesive 21 is preferably a so-called adhesive gel, which is permanently elastic and adheres to the surface of the housing 111 with an adhesive force. The adhesive gel can be made, for example, from polyurethane and preferably contains no plasticizers. Alternatively, a curing adhesive can be used as the adhesive 21. It is also conceivable to use a double-sided adhesive tape.

[0024] To mount the junction box 11 on the back 3 of the PV module 1, the Fig. 3b, the prepared junction box 11 is placed over the bent-up connection contacts 5 so that they protrude through the opening 115. Due to the adhesive properties of the adhesive 21, the junction box 11 is fixed to the rear side 3 of the PV module 1 at least so well that further assembly steps can also be carried out automatically on the unit consisting of the PV module 1 and the junction box 11.

[0025] The Fig. 4 shows a section comparable to that in Fig. 2, the PV module 1 with attached junction box 11, whereby here (unlike in the Fig. 3a, b shows the junction box 11 with the connected connecting cable 14. In the next assembly step, the connection contacts 5 are connected to the corresponding contact elements of the junction box 11.

[0026] This can be accomplished by soldering, clamping, crimping, or spot welding. In the next process step, a liquid and subsequently hardening potting compound is introduced from above into the cavities of the junction box 11. This potting compound also flows through the opening 115 into the pyramid-shaped cavity 114. Any air contained in this cavity 114 can escape through the connection area 116, which is initially not reached by the potting compound. Lateral escape from the cavity 114 is prevented by the adhesive 21.

[0027] Fig. 5 shows the arrangement of photovoltaic module 1 and attached junction box 11 after complete filling of the casting compound and fitting of a cover 16 in a representation analogous to the Fig. 4. Alternatively, it can also be provided that the cured casting compound itself represents the upper surface of the junction box 11.

[0028] The potting compound protects the connection area 116 and the connection contacts 5 from moisture penetration, thus preventing corrosion in this area. While the adhesive 21 also prevents moisture penetration from the sides beneath the junction box 11, the potting compound provides additional protection. Furthermore, the potting compound secures the junction box 11 to the rear side 3 beyond the adhesive effect of the adhesive 21.

[0029] Thus, in the arrangement according to the invention comprising PV module 1 and junction box 11, the adhesive 21 has in particular a temporary adhesive function during the assembly process until the potting compound has hardened, as well as an additional permanent sealing function.

[0030] In the Fig. 6a and Fig. 6b is similar to the Fig. 3a and Fig. 3b shows a second exemplary embodiment of a junction box 11 of a connection arrangement 10. Essentially, the structure of the connection arrangement 10 and in particular of the junction box 11 corresponds to that of the first exemplary embodiment, to which reference is hereby explicitly made. In contrast to the first exemplary embodiment, a circumferential groove 117 is provided in the outer region of the underside 113 of the junction box 11 in the second exemplary embodiment. During the assembly process, the adhesive 21 can be applied, as shown in Fig. 6b, can be introduced directly into the groove 117. The groove 117 leads to a larger surface between the adhesive 221 and the junction box 11, which increases the adhesive effect. Alternatively, the adhesive 21 can be inserted into the groove 117, similar to the embodiment of the Fig. 3b, are applied to the underside 113. The adhesive 21 is applied to the area of ​​the underside 113 that lies within the circumferential groove 117. In this case, the groove 117 then serves to absorb excess adhesive 21 that is pushed outward, thereby preventing any possible contamination of the rear side 3 of the PV module 1. Reference symbol 1 photovoltaic module (PV module) 2 frames 3 Back 4 Contact area 5 connection contact 10 Connection arrangement 11 Junction box 111 housings 112 top 113 subpage 114 Cavity 115 Opening 116 Connection area 117 groove 12 Connection unit 13 Bypass diode 14 connection cables 15 connectors 16 lids 20 Applicator 21 Adhesives

Claims

[1] Photovoltaic module (1) with at least one connection contact (5) and at least one connection box (11) which is arranged on a rear side (3) of the photovoltaic module (1) and which has a housing (111) which has at least one opening (115) towards the rear side (3) for the passage of the at least one connection contact, characterized by that an adhesive (21) for fixing and / or sealing is present between the at least one junction box (11) and the rear side (3) of the PV module (1), and that for fastening the junction box (11) there is a cavity (114) within the junction box (11), which cavity extends from the opening (115) to the rear side (3) of the PV module (1), widens towards the rear side (3) and is filled with a casting compound. [2] Photovoltaic module (1) according to claim 1, wherein the adhesive (21) is a permanently elastic adhesive gel. [3] Photovoltaic module (1) according to claim 2, wherein the adhesive gel comprises polyurethane. [4] Junction box (11) with a housing (111) which has at least one opening (115) towards a bottom side for the passage of at least one connection contact (5) of a photovoltaic module (1), characterized by that in the housing (111) a cavity (114) widening towards the underside extends from the opening (115). [5] Junction box (11) according to claim 4, wherein the cavity (114) widening towards the underside is pyramid-shaped. [6] Junction box (11) according to claim 4 or 5, which has a connecting unit (16) for contacting the at least one connection contact (5) and / or a connection cable (14). [7] Junction box (11) according to one of claims 4 to 6, comprising at least one bypass diode (13). [8] Junction box (11) according to claim 6 and 7, wherein the at least one bypass diode (13) is arranged on the connection unit and / or is electrically connected thereto. [9] Junction box (11) according to one of claims 6 to 8, wherein the connecting unit (16) is formed by a punched grid.

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