Bypass element, and photovoltaic module comprising at least one bypass element

Abstract

The invention relates to a bypass element (13), in particular for a photovoltaic module (1), comprising a housing (131) in which at least one semiconductor component is arranged and from which at least two connection lugs (132) protrude. The bypass element (13) is characterised in that one of the surfaces of the connection lugs (132) protrudes from the housing (131) flush with an underside of the housing (131), and in that at least one of the connection lugs (132) is provided with a solder preform (134). The invention also relates to a photovoltaic module (1) comprising at least one such bypass element (13).

Description

[0001] Bypass element and photovoltaic module with at least one bypass element

[0002] The invention relates to a bypass element, in particular for a photovoltaic module, comprising a housing in which at least one semiconductor component is arranged and from which at least two terminal lugs protrude. The invention further relates to a photovoltaic module with at least one bypass element.

[0003] In photovoltaic modules, hereinafter abbreviated as PV modules, it is common practice to connect the connection points of existing cell arrays (usually three cell arrays) connected in series via contact strips to a junction box in which at least one bypass element is located. Typically, a bypass element is provided for each cell array, which is connected in parallel with the respective cell array.

[0004] Without the bypass elements, the series connection of the cell arrays would result in the least irradiated cell array determining the total current of the PV module. This behavior is prevented by the bypass elements, resulting in higher efficiency in partially shaded PV modules. Diodes or transistors connected as diodes are used as bypass elements.

[0005] A PV module with a junction box containing bypass diodes is described, for example, in the publication US 2016 / 0141435 A1. The contact strips leading from the cell arrays to the junction box are connected to contact elements within the junction box, which also connect the bypass diodes with their terminal lugs and connecting cables. The contact elements must be manufactured, e.g., as a stamped grid, which requires material and costs. Furthermore, the installation of the contact elements in the junction box and the connection to the contact strips, on the one hand, and the bypass diodes and connecting cables, on the other, is complex.

[0006] It is an object of the present invention to provide bypass elements that can be installed in a junction box of a PV module as simply as possible and with minimal additional material expenditure. A further object is to describe a PV module with a junction box having at least one bypass element, in which the junction box can be installed as easily as possible.

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

[0008] A bypass element according to the invention of the type mentioned at the outset is characterized in that the connecting lugs emerge from the housing with a surface flush with a bottom side of the housing and that at least one of the connecting lugs is provided with a solder preform.

[0009] Because the bypass element's terminal lugs extend flush with the underside of the bypass element's housing, the bypass element can be placed flat on one end of a contact strip (or multiple contact strips) within the junction box and soldered directly to the contact strip(s). This means that no separate contact elements are required for the junction box to contact the contact strips of the cell arrays. A further advantage is that the contact strips do not need to be bent upwards or otherwise laboriously prepared. Instead, their ends can be soldered to the bypass element's terminal lug while lying flat on the back of the PV module. This reduces the parts and assembly effort for the junction box.

[0010] The connection process itself is also made simple by the use of preformed solder parts: The junction box is prepared by inserting the required number of bypass elements into pre-prepared receptacles. The junction box is open at the bottom, at least in the area of ​​the bypass elements, with the preformed solder parts of the bypass elements being accessible through the opening. The junction box is then placed on the back of the photovoltaic module for assembly. This can be done after a backsheet has first been applied to the PV module and then removed again in the connection area. The junction box is placed in such a way that at least one preformed solder part is positioned on or above the flat end of the contact strip. Finally, heat is introduced into the connection lug, e.g. from the junction box, which melts the preformed solder part and solders the bypass element to the contact strip. The heat can, e.g.The soldering iron can be used to insert the terminal lug into the contact strip using a heated die, which simultaneously presses the terminal lug onto the contact strip. It is also possible to generate heat inductively in the terminal lug.

[0011] In an advantageous embodiment of the bypass element, the at least one connecting lug comprises a crimp contact for connecting to a cable, in particular a connecting cable for the PV module. The crimp contact is preferably arranged or formed at a free end of the connecting lug.

[0012] The connecting cable can be positioned with a stripped section in this crimp contact and crimped there using an appropriate tool. It is also conceivable to perform the crimping before inserting the bypass element into the junction box, thus inserting the connecting cable together with the bypass element.

[0013] In an advantageous embodiment of the bypass element, the semiconductor component is a diode or a transistor, in particular a MOSFET (Metal Oxide Semiconductor Field-Effect Transistor). If the semiconductor component is a transistor, it is preferably already internally wired to act like a diode. The bypass element then typically has two terminal lugs, regardless of whether the semiconductor component is a diode or a transistor.

[0014] In one embodiment, the at least two terminal lugs of the bypass element are each provided with a crimp contact for connecting to a cable. Depending on the position of the bypass element in the junction box, usually only one of the two crimp contacts is required. Even if one or both crimp contacts of a bypass element are unused, they do not cause any further disruption. However, this design with crimp contacts on both terminal lugs advantageously reduces the number of parts required.

[0015] A PV module according to the invention has at least one cell arrangement with a plurality of solar cells connected in series and / or parallel. At least one junction box is arranged on a rear side of the PV module, with metallic contact strips along the rear side leading from connection points of the at least one cell arrangement to the at least one junction box. The PV module is characterized in that the junction box has at least one bypass element of the type described above, with at least one connection lug that is soldered to at least one of the contact strips. Preferably, the PV module also has at least one connection cable that is connected to a crimp contact that is arranged or formed on the at least one connection lug of the at least one bypass element.Particularly preferably, the PV module has at least two cell arrangements connected in series with each other, to which at least one such bypass element is connected in parallel.

[0016] The PV module according to the invention does not require separate contact elements for the junction box to contact the contact strips of the cell array(s). Instead, the bypass elements serve directly to contact the contact strips and, if necessary, also the connecting cables. This reduces the parts and assembly effort for the junction box and thus the PV module.

[0017] Preferably, the terminal lugs protrude beyond the underside of the junction box to extend through an opening in a rear cover layer of the photovoltaic module to the contact strips. The described mounting method can be used for PV modules in which the rear cover layer is a backsheet. With correspondingly further protruding terminal lugs, it can also be used for a PV module that has a glass pane as the rear cover layer.

[0018] The invention is explained in more detail below using exemplary embodiments and figures. The figures show:

[0019] Figure 1 is an isometric view of a PV module without a junction box, looking at its rear side;

[0020] Figure 2 is an enlarged section of Figure 1;

[0021] Figure 3 shows a detailed view of the PV module of Figure 1 with the junction box mounted in a plan view;

[0022] Figure 4a, b each show a spatial representation of the housing of the junction box according to Figure 3 with a view of its top and bottom respectively;

[0023] Figures 5a-c show various views of a bypass element of the junction box according to Figure 3; Figure 6 shows a connection area of ​​the rear side of a PV module with and without positioned bypass elements;

[0024] Figures 7a-d show various representations of another example of a junction box for a PV module with a bypass element according to the invention; and

[0025] Figures 8a-e show various representations of another example of a junction box for a PV module with a bypass element according to the invention.

[0026] In all figures, identical reference symbols identify identical or identically functioning elements. For reasons of clarity, not every element in every figure is provided with a reference symbol.

[0027] Figure 1 shows a top view of a photovoltaic module (PV module) 1, viewed from its rear side. The PV module 1 has a frame 2 and the actual module structure. The module structure comprises a front-facing, transparent carrier substrate, e.g., made of glass or plastic, in particular polycarbonate, onto which a semiconductor layer stack is applied. The layer stack is laterally divided into a plurality of rectangular cells 3, wherein adjacent cells 3 can be electrically coupled to one another by applied connecting layers, in particular connected in series.

[0028] In the PV module 1, the module structure comprises one or more cell arrangements 4a-c - specifically three here - each of which has a plurality of cells 3 forming a unit.

[0029] A center line 5 of the PV module 1 runs parallel to its (shorter) transverse sides and centrally with respect to the (longer) long sides of the PV module 1, the base area of ​​which is rectangular. Each of the cell arrangements 4a-c comprises two strips with cells 3 running in the longitudinal direction of the PV module 1, with half of the cells 3 of a strip (in the illustration in Figure 1) lying above the center line 5 and the other half below it. In each cell arrangement 4a-c, the cells 3 lying above and below the center line 5 are connected in series and accordingly form a string. Each cell arrangement 4a-c thus comprises two strings, each of which is connected in parallel in the area of ​​the center line 5. The contact points of the cell arrangements 4a-c are therefore also located in this area of ​​the center line 5.

[0030] In Figure 1 (as well as Figures 2 and 3), the PV module 1 is shown without an insulating backing layer, e.g., a backsheet, on the back of the module structure that protects against environmental influences. It is common practice for PV modules to laminate such a backsheet, for example, made of EVA (ethylene-vinyl acetate), PUR (polyurethane), or PA (polyamide), which is interrupted only at selected points to allow the exit of connection contacts for the cell arrangements 4a-c. Figures 1 and 2 also show the PV module 1 before the installation of a junction box.

[0031] Figure 2 shows a section of Figure 1 in the area of ​​the center line 5 and the cell arrangements 4a and 4b.

[0032] In the area of ​​the center line 5, the cells 3 of the two halves of the PV module 1 are spaced apart from each other so that a strip of the carrier substrate along the center line 5 is free of cells 3 and offers the possibility of positioning contact strips 6 between the cells 3 of the two halves.

[0033] In the middle cell arrangement 4b, two such contact strips 6 run along the center line 5 from the outer edges of the cell arrangement 4b inwards to a central region 8b which lies between the two cell strips forming the cell arrangement 4b.

[0034] Similarly, a contact strip 6 runs along the center line 5 in the area of ​​the cell arrangement 4a from the edge area to a central area 8a of the cell arrangement 4a. This central area 8a is positioned, analogously to the central area 8b, around the intersection between the center line 5 and the two strips of cells 3 that form the cell arrangement 4a. It is shown again in an enlarged form in the upper part of Figure 6.

[0035] In the PV module 1 shown, the contact strip 6 continues along the center line 5 until it also reaches the central region 8b of the cell arrangement 4b. It thus runs in sections above the contact strip 6, which leads from the edge of the cell arrangement 4b into the central region 8b. To prevent the two contact strips 6 from making contact with each other, they are insulated from each other between the central region 8a of the cell arrangement 4a and the central region 8b of the cell arrangement 4b. For this purpose, an insulating strip 7 is arranged along the center line 5 between the two contact strips 6. The insulating strip 7 can be provided with a double-sided adhesive layer so that it is fixed to the lower contact strip 6 and, if applicable, to the adjacent, exposed areas of the carrier substrate, and also fixes the upper contact strip 6 on its upper side.

[0036] Through this upper contact strip 6, one pole of the cell arrangement 4a is guided into the central region 8b of the cell arrangement 4b. The second pole of the cell arrangement 4a is connected, not visible here, below the insulating strip 7 to one of the contact strips 6 assigned to the cell arrangement 4b. In this way, the two cell arrangements 4a and 4b are internally connected in series, with both poles of the cell arrangements 4a and 4b being available in the central contact area at the same time to connect bypass elements in parallel. This will be explained in more detail below in connection with Figures 4-6.

[0037] In the same way, the outer pole of the cell arrangement 4c is guided via a contact strip 6, which is arranged on an insulating strip 7, from a connection point on the right outer side of the PV module 1 (relative to the illustration in Figure 2) into the central region 8b of the cell arrangement 4b.

[0038] As a result, the ends of four contact strips 6 for contacting the cell arrays 4a-c are brought together in this central area 8b of the cell array 4b. Advantageously, the ends of all four contact strips 6 in this central area 8b can be covered by a single junction box, contacted by external connecting cables, and interconnected with bypass elements.

[0039] Figure 3 shows a section of the back of the PV module 1 with such a junction box 11 attached.

[0040] The junction box 11 is positioned above the central region 8b of the middle cell arrangement 4b along the center line 5. Despite its compact dimensions, which are narrower than the width of the middle cell arrangement 4b, the junction box 11 covers the exposed ends of the four contact strips 6 with its housing 111. An insulating backsheet, which covers the PV module 1 on the rear side of the module structure with the exception of the ends of the contact strips 6 and thus insulates and protects it, is also not shown in Figure 4 in order to show the positioning of the junction box 11 on the PV module 1. The junction box 11 is also shown open. During operation, it is closed with a cover and / or a potting compound, which protects it against the ingress of moisture and dust.

[0041] On each of the outer transverse sides of the housing 111, a connection area 112 is formed in which the ends of connecting cables 14 are connected, each of which has a plug 15 at its free end. Within the junction box, three bypass elements 13 are mounted, which are connected in parallel to the individual cell arrangements 4a-c.

[0042] The illustrated junction box 11 does not have any separate contact elements or the like with the aid of which the contact strips 6, the bypass elements 13 and the connecting cables 14 are contacted.

[0043] Instead, the bypass elements 13 are designed to contact the contact strips 6 and the connecting cables 14 without the need for separate contact elements 12.

[0044] Details of the arrangement of the bypass elements 13 in the housing 111 of the junction box 11 are shown in Figures 4a and 4b. Both figures show the junction box 11 equipped with the bypass elements 13, separate from the PV module 1 and without the connected connection cables 14.

[0045] More detailed views of the bypass elements 13 are shown in Figures 5a-c, with Figures 5a and 5b showing spatial representations from different perspectives and Figure 5c showing a side view.

[0046] Each bypass element 13 has a housing 131 in which the corresponding semiconductor component, for example a diode or a MOSFET transistor connected as a diode, is arranged and from which connection lugs 132 emerge on two opposite sides.

[0047] The two terminal lugs 132 represent the two electrodes of the bypass element 13. They protrude from the housing 131 flush with the underside of the housing 131. Such a design of the bypass elements 13 facilitates soldering to the underlying contact strips 6.

[0048] In the bypass elements 13 of the second exemplary embodiment, the connection lugs 132 each merge outwardly into a crimp contact 133. In this way, each connection lug 132 can be connected to a cable, for example, the connection cable 14 of the connection arrangement 10. In this regard, it can be seen in Figures 4a and 4b that one of the crimp contacts 133 of each of the outer two bypass elements 13 protrudes into the connection area 112, so that a connection cable 14 inserted there is positioned with its stripped section in this crimp contact 133 and can be crimped there with an appropriate tool. If necessary, crimping can also take place before inserting the bypass element 13 into the junction box 11, i.e., the connection cable 14 can be inserted together with the bypass element 13.

[0049] To reduce the number of parts, the middle of the three bypass elements 13 used is also equipped with crimp contacts 133. These are then unused, but do not cause any interference. Alternatively, it is also conceivable to equip only the outer bypass elements 13 with crimp contacts 133, or even just one crimp contact 133 each. This allows the junction box 11 to be made even smaller, but increases the number of different components that must be kept in stock.

[0050] Furthermore, as Figures 4b and 5b show, each terminal lug 132 has a pre-soldered soldering element 134 on its underside, i.e., the side flush with the housing 131. As can be seen from Figure 4b, the pre-soldered soldering elements 134 of the bypass elements 13 protrude downwards beyond the junction box 11 and, in particular, its underside 114. When the junction box is placed on the back of the PV module, these pre-soldered soldering elements 134 are positioned on the contact strips 6 and can be soldered to the underlying contact strip 6 by applying heat while the junction box 11 is in place.

[0051] The arrangement of the bypass elements 13 in relation to the underlying contact strips 6 is shown again in Figure 6. Figure 6 shows, in its upper half, the central region 8b of the middle cell arrangement 4b of the PV module 1, in which the contact strips 6 of the three cell arrangements 4a-c end. The two middle contact strips are designed to be so long that they reach up to the solder preforms 134 of the middle bypass element 13.

[0052] In the lower section of Figure 6, the three bypass elements 13 are shown without the junction box 11 at the positions where they will be soldered to the contact strips 6. It can be seen that the left bypass element 13, with its connection lugs 132, is currently contacting the two left contact strips. Accordingly, the right bypass element 13 contacts the two right contact strips 6. Finally, the middle bypass element 13 contacts the two middle contact strips 6. In this way, the bypass elements 13 are connected to both the contact strips 6 and the connecting cables 14 by means of the preformed solder parts 134 and the crimp contacts 133, respectively.

[0053] No additional metallic contact element is required within the junction box 6. The bypass elements 13 can, for example, be clamped into the junction box 11.

[0054] During assembly, the junction box 11 is fixed to the back of the PV module 1 by means of an adhesive layer arranged on its underside 114, usually on a previously applied backing film. A previously applied hot melt adhesive, for example, can be used as the adhesive layer. With the junction box 11 fixed, the bypass elements 13 can be soldered to the contact strips 6 by applying heat to the connection lugs 132 from above through the junction box 11. Here, for example, a heated stamp can be used or heat can be applied via an induction process. The heat melts the solder preforms 134, whereby the respective connection lug 132 is soldered to the underlying contact strip 6. The bypass elements 13 are then held in position in the junction box 11 by the solder in addition to being clamped.Finally, the junction box 11 can be potted, which protects the bypass elements 13 and the underlying contact area and at the same time firmly mounts the junction box 11 to the back of the PV module 1.

[0055] Figures 7a-d and 8a-e each show, in different representations, another example of a junction box 11 for use on a rear side of a PV module, in which a bypass element 13 according to the invention is arranged.

[0056] Figures 7a and 8a show a housing 111 of the junction box 11, each with a view of an underside 114 of the housing 111. Figures 7b and 8b show the junction box 11 in a side view, Figures 7c and 8c in a sectional view, and Figures 7d and 8d in a plan view of the upwardly open housing 111. Figures 7a-d and 8a-d show the junction box 11 without a connection cable and separately from the PV module, on the back of which the junction box 11 can be mounted.

[0057] Figure 8e shows the junction box 11 for one of the two examples in a side section similar to Figure 8c, with a connecting cable 14 mounted in this illustration. Furthermore, the junction box 11 is closed by a cover 117, on which a holder 115 for a plug 15 located at the end of the connecting cable 14 is provided.

[0058] Like the junction box 11 previously shown in Figures 3 and 4a, b, the junction box 11 of Figures 7a-d and 8a-e is also characterized by the use of the bypass element 13 according to the invention. The bypass element 13 has connection lugs 132 that emerge laterally from a housing 131. Solder preforms 134 are arranged on each side of the connection lugs 132 facing downwards towards the PV module. The solder preforms 134 protrude above the underside 114 of the housing 111 and can contact contact strips or other contact elements on the rear side of the PV module. After the junction box 11 has been placed and fixed on the rear side of the PV module, the solder preforms 134 are melted by heat input, establishing a connection to the contact strip or other contact elements.

[0059] Also similar to the junction box 11 shown in Figures 3a and b, the terminal lugs 132 terminate in crimp contacts 133, which can then be connected within the housing 111 to a connecting cable, for example, the connecting cable 14 shown in Figure 8e. A cable guide 116 is formed on one transverse side of the junction box 11 shown for routing the connecting cable.

[0060] Unlike the previously shown junction box 11, the embodiments of Figures 7a-d and 8a-e provide for only one connection cable 14 to be connected to each junction box 11. To connect a PV module, two such junction boxes 11 are used at different locations on the rear of the PV module.

[0061] The two versions of the junction box 11 shown in Figures 7a-d and 8a-e differ in that in the example shown in Figures 8a-8e, the connection lugs 132 with the preformed solder parts 134 protrude further beyond the underside 114 of the junction box 11 than in the embodiment shown in Figures 7a-7d. The two junction boxes 11 are designed for different types of PV modules: Specifically, the design of the junction box shown in Figures 8a-e is designed for a PV module whose rear cover layer is formed by a glass pane and not by a (thinner) backsheet. The further protruding section of the connection lug 132 compensates for the material thickness of the rear glass pane of the PV module, so that the preformed solder parts 134 protrude through an opening in the glass pane to the contact strips or other contact elements of the PV module, even with the greater material thickness of the rear glass pane.

[0062] Regardless of the PV module design, the junction box can be fixed to the back of the PV module in the same manner as described above, for example, with hot melt adhesive. The solder preforms 134 can be melted by applying heat via a heated die or by an induction process to solder the respective terminal lug 132 to the underlying contact strip or contact element. The junction box can then either be potted and / or, as shown in Figure 8e, closed with the cover 117.

[0063] Reference symbol

[0064] 1 photovoltaic module (PV module)

[0065] 2 frames

[0066] 3 cell

[0067] 4a-c Cell arrangement

[0068] 5 Center line

[0069] 6 contact strips

[0070] 7 insulating strips

[0071] 8a, b Central area

[0072] 10 Connection arrangement

[0073] 11 Junction box

[0074] 111 housings

[0075] 112 Connection area

[0076] 114 subpage

[0077] 115 Holder for plug

[0078] 116 Cable entry

[0079] 117 lids

[0080] 13 Bypass element

[0081] 131 housings

[0082] 132 connecting lug

[0083] 133 Crim contact

[0084] 134 Solder preform

[0085] 14 connection cables

[0086] 15 plugs

Claims

Claims 1. Bypass element (13), in particular for a photovoltaic module (1), comprising a housing (131) in which at least one semiconductor component is arranged, and from which at least two connection lugs (132) protrude, characterized in that the connection lugs (132) emerge from the housing (131) with one of their surfaces flush with an underside of the housing (131) and that at least one of the connection lugs (132) is provided with a solder preform (134).

2. Bypass element (13) according to claim 1, wherein the solder preform (134) is arranged on the surface of the at least one terminal lug (132) which is flush with the underside of the housing (131).

3. Bypass element (13) according to claim 1 or 2, wherein at least one of the terminal lugs (132) comprises a crimp contact (133) for connection to a cable.

4. Bypass element (13) according to one of claims 1 to 3, wherein the at least two connection lugs (132) are each provided with a solder preform (134).

5. Bypass element (13) according to claim 3 and 4, wherein the at least two connection lugs (132) each comprise a crimp contact (133) for connection to a respective cable.

6. Bypass element (13) according to claim 3 or 5, wherein the crimp contact (133) is arranged or formed at a free end of the connection lug (132).

7. Bypass element (13) according to one of claims 1 to 6, wherein the semiconductor component is a diode or a transistor.

8. Photovoltaic module (1) with at least one cell arrangement (4a-c) which has a plurality of solar cells (3) connected in series and / or in parallel, and at least one junction box (11) arranged on a rear side of the photovoltaic module (1), wherein metallic contact strips (6) are arranged along the rear side of connection points of the at least one Cell arrangement (4a-c) to the at least one junction box (11), characterized in that the junction box (11) has at least one bypass element (13) according to one of claims 1 to 7, with at least one connection lug (132) which is soldered to at least one of the contact strips (6).

9. Photovoltaic module (1) according to claim 8, wherein the connection lugs (132) protrude beyond an underside of the junction box (11) in order to protrude through an opening in a rear cover layer of the photovoltaic module (1) as far as the contact strip (6).

10. Photovoltaic module (1) according to claim 9, wherein the rear cover layer is a backsheet or a glass pane.

11. Photovoltaic module (1) according to one of claims 8 to 10, comprising at least one connecting cable (14) which is connected to a crimp contact (133) which is arranged or formed on the at least one connecting lug (132) of the at least one bypass element (13).

12. Photovoltaic module (1) according to one of claims 8 to 11, comprising at least two cell arrangements (4a-c) connected in series with one another, to each of which at least one bypass element (13) is connected in parallel.

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