CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to PCT Application No. PCT/CA2016/051288 filed on November 4, 2016, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

[0002] The following relates to junction box assemblies for solar PV panels.

DESCRIPTION OF THE RELATED ART

[0003] Photovoltaic solar panels utilize a mechanism for electrically connecting one to another for the purpose of delivering the collected energy to an outside system. Typically, this is done via a "junction box" wherein electrical leads from the panel are ultimately connected to output wires and connectors. The junction box commonly contains an electronic circuit, in many cases a simple diode setup comprising one or more diodes, which may serve various purposes in the solar panel. In other cases, the electronics may be more complex and may serve functions such as shutting down the solar panel(s) for safety purposes, performing maximum power point tracking, enabling communications, enabling location tracking, or other purposes.

[0004] A typical setup for a junction box is shown in FIG 2. Busbars from a solar panel laminate enter the junction box, are connected to the electronic circuit inside the box, and in turn connected to output connections. The output connections are typically done using insulated wire connected to connectors, but occasionally directly at the junction box bulkhead.

[0005] The panel manufacturer normally fixes the junction box to the back of the panel by some mechanical arrangement, which may include either an RTV or silicone sealant/glue, epoxy, or tape. The box has an opening in the bottom for the busbars to enter the box and connect inside to the circuit. The manufacturer makes these connections using the mechanisms and/or techniques required by the particular junction box design. These can include, for example soldering, welding, mechanical clips or any combination thereof. If needed, connections can also be made to the electrical output elements (i.e., cables, bulkhead connectors, etc.) using similar methods.

[0006] The panel manufacturer may then take steps to ensure the electronics are protected, which could occur in a variety of ways. For example, the manufacturer may encapsulate the entire contents in a pottant material before putting on a lid. The

manufacturer may also choose a junction box enclosure which has a seal around the base and the lid which would protect it, possibly with a pressure relief vent. In these cases, the manufacturer could proceed to attaching the lid of the junction box to the junction box base.

[0007] Solar panels are typically sold with long warranties, which exceed the normal life expectations of typical low-cost electronic assemblies. In traditional solar panels, diode failures in junction boxes are the among the most common failure mode of solar panels. Moreover, as electronics in junction boxes become more complex, there is an additional or increased risk of failure during the life of the solar panel deployment. As well, the value of the electronics in the junction box is normally small compared to the value of the rest of the solar panel, and it is therefore desirable to not have to discard otherwise well-functioning solar panels when there is an issue in the electronics in the junction box.

[0008] It is an object of the following to address at least one of the above-noted disadvantages.

SUMMARY

[0009] In one aspect, there is provided a junction box assembly for a photovoltaic (PV) solar panel, comprising: a base to be attached to the panel, the base providing at least one base connection to one or more busbars from the panel; and a removable lid comprising electronics for operating the panel, at least one lid connection for mating with the at least one base connection to connect the electronics in the lid to the busbars from the panel, and at least one output connection cable.

[0010] In another aspect, there is provided a connection assembly for electronics utilized by a PV solar panel, the connection assembly comprising: at least one busbar portion that is wrapped over at least one corresponding protrusion from a base connected to the panel; and at least one connection element extending from a lid for the base, the at least one connection element positioned to engage the at least one protrusion to connect electronics in the lid to the at least one busbar portion.

[0011] In yet another aspect, there is provided a junction box assembly comprising a lid with electronics overmolded to provide a structure to mate with a base connected to a PV solar panel.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Embodiments will now be described with reference to the appended drawings wherein:

[0013] FIG. 1 A is a perspective view of a solar panel mounted on a rack support; [0014] FIG. 1 B is a perspective view of a solar panel mounted to a rooftop via rails;

[0015] FIG. 2 is a perspective view of the rear side of a solar panel in a typical configuration for a junction box, shown without connectors on the cables;

[0016] FIG. 3 is a schematic profile view of a junction box configuration with electronics in the lid thereof;

[0017] FIG. 4 is a perspective view of a junction box base;

[0018] FIG. 5 is a perspective view of a junction box lid for the base shown in FIG. 4;

[0019] FIG. 6 is a perspective view shown assembly of the base and lid shown in FIGS. 4 and 5;

[0020] FIG. 7 is a perspective view of another junction box base and lid;

[0021] FIG. 8 is a perspective view of a junction box lid supporting diode assemblies;

[0022] FIGS. 9A and 9B are perspective views of a junction box base for the lid in FIG.

8;

[0023] FIG. 10 is a perspective view of a junction box base variation to that shown in FIG. 9;

[0024] FIG. 1 1 is a perspective view of a junction box base with multiple busbars connecting through a single connector element;

[0025] FIG. 12 is a perspective partial cross-sectional view of an assembled junction box with oversized lid;

[0026] FIG. 13 is an exploded version of FIG. 12;

[0027] FIG. 14 is a perspective view from below of the embodiment shown in FIGS. 12 and 13;

[0028] FIG. 15 is a perspective view of a variation of the embodiment shown in FIG. 14;

[0029] FIG. 16A is an alternative perspective of the embodiment shown in FIG. 15;

[0030] FIG. 16B is a perspective view of a base with flyouts in variation to that shown in FIG. 16A;

[0031] FIG. 17 is a perspective exploded view of an overmolded lid and corresponding base;

[0032] FIG. 18 is a front elevation view of the lid and base of FIG. 17 in an assembled form; and [0033] FIG. 19 is a side elevation view of the lid and base of FIG. 17 in an assembled form.

DETAILED DESCRIPTION

[0034] The following addresses a desire for a replaceable electronics solution to solar panel design.

[0035] Whereas traditional junction boxes have the circuit in the portion of the junction box assembly which is permanently affixed to the solar panel, the following presents embodiments that reverse this convention, and have the electronics and outputs in the lid of the assembly. In such embodiments, the busbars from the PV panel laminate are directed into a junction box base where they are led to fixed point terminations. The lid with the electronics and outputs pre-applied may then be mounted to the base, simultaneously making the electronic connections and sealing the enclosure. The assembled unit would then be ready for testing and deployment. In the event of a failure of the electronics, the lid can be removed and replaced with a new one, and the faulty electronics can be refurbished or discarded. In either case, the solar array can be back up and running with greatly reduced impact to operations. Described below are various configurations for accomplishing this connection.

[0036] The following solutions can be configured to work with any electronics that are modified, adapted or designed, to suit the requirements of mounting and/or housing the electronics in one or more of the various configurations described herein. For example, FIG. 1A illustrates an example of a solar panel 10 mounted on a rack 12, e.g., that can be deployed in a suitable orientation and mounted to the ground or other surface. The solar panel 10 includes a frame 14 and a junction box as discussed in greater detail below. FIG. 1 B illustrates another example in which a set of rails 16 is used as racking to mount solar panels 10 to a rooftop 18.

[0037] FIG. 2 illustrates a typical junction box enclosure 50 mounted to the rear of a solar panel 10. In FIG. 2 it can be seen that output connector cables 60 extend from the enclosure.

[0038] A junction box enclosure 100 according to the principles described herein, wherein electronics are supported in the lid thereof, is shown schematically in profile in FIG. 3. It may be noted that in the configuration shown in FIG. 3, several relatively expensive connectors, cables, and an electronics enclosure may be eliminated or reduced by integrating the electronics into a junction box 100. [0039] As shown in FIG. 3, in this configuration a top lid enclosure 104 is secured to a bottom enclosure 106 to contain the junction box and other electronics. The bottom enclosure 106 is secured to the back of the laminate 25 with the top lid enclosure 104 containing electronic components that are secured to each other when the enclosure is assembled. In this example, the top lid enclosure 106 contains a circuit board 108 for electronics with an upper component 1 10 that mates with a lower component 1 14 in the bottom enclosure 106. For example an upper connection mechanism 1 12 can be used to be secured to a lower connection mechanism 1 16 on the lower component 1 14. This enables the circuit board 108 to be connected to the busbar 120 from the PV panel via one or more connections 1 18. It can be appreciated that the components 1 10, 1 16 and connections mechanism 1 12, 1 14 can also be embodied in the same component (e.g. a circuit component that includes the connection mechanism). As shown in this example, all of the normal junction box electronics as well as any special electronics for the particular application may be contained in the top lid 104 and be readily and easily assembled if the lid subassembly 104 is ready for the panel manufacturer. It may be appreciated that any combination of electronics may be split between the two enclosure subassemblies 104 and 106 in ways that lead to performance and assembly advantages for each individually and/or in combination.

[0040] The configuration shown in FIG. 3 provides an advantageous thermal option by placing the electronics as thermally connected to the top lid enclosure 104. Moreover, the top lid enclosure 104 can be easily removed for serviceability, and eliminates the need for multiple enclosures.

[0041] Various configurations that enable the busbars 120 on the laminate 25 to connect to lid-mounted electronics 108 via a connector or other connection mechanism will now be described, making reference to FIGS. 4-19.

[0042] FIG. 4 shows a representation of a base 206 which can be mounted to a PV panel. The base 206 serves as an ingress point for the busbar connections 208 from the laminate, and a mechanism for ensuring there is a constant connection point for the electronics in the lid which will connect with them. Shown in FIG. 4 are a set of teeth 210, which could be either part of a plastic mold, or a plated or non-plated sheet-metal insert, either separate or overmolded in the base. This effectively turns the base 206 into a large connector. While four busbar connection points are shown in FIG. 4, it can be appreciated that the configuration shown can be modified for 2, 3, 5, 6 connection points and so forth. [0043] FIG. 5 shows a representation of an electronics circuit 212 in a lid 214 that is sized to fit with the base 206 shown in FIG. 4. It may be noted that the shape of the mating connections to the base 206 are such that the lid 214 slides over and engages the base 206. The fact that the mating connections of FIG. 5 slide over the wrapped protrusions of FIG. 4 as shown in FIG. 6 means that there is an added degree of freedom and tolerance leeway in the mating contact. In this example, the "omega" shaped clips 216 provides vertical tolerance for the amount of engagement with the teeth 210 in the base 206. The output cables 218, which are connected into and supported by the lid 214 are also shown in FIGS. 5 and 6. It can also be appreciated that while FIGS. 4 and 6 illustrate a peripheral seal 220 to prevent contaminates such as moisture from entering the junction box 100, 200, other protections can be applied in addition to or instead, for example, by applying potting material to the electronics 212. It can also be noted that several means of securing the electronics circuit board 212 to the lid 204 may be employed, including crush or crash ribs, staking, screws and washer combinations, glue or tape or adhesive, or any other mechanical means.

[0044] FIG. 7 shows an alternative example to what is shown in FIGS. 4-6, wherein the electronics in the junction box 300 are more complex. FIG. 7 also illustrates that the enclosures 304, 306 of the junction box 300 can be of different shapes and sizes and can connect to each other in different ways (see corners of 304 and 306). Similarly, the electronics can be retained in the lid 304 in various ways, such as crush and crash ribs, plastic clips, screws, screw-washer combinations, glue, RTV, etc.

[0045] FIG. 8 shows a representation of a lid 404 wherein the electronics are limited to typical diode assemblies 412 with portions of sheet metal or other conductive elements 414 in between. This is similar to one way that such diode assemblies 412 have been mounted in the base of a traditional junction box, adapted herein to be provided in the lid 404. In this view, the sheet metal elements 414 are turned up at the ends 416 to connect to teeth 410 in a correspondingly sized base 406, shown in FIG. 9A. As can be seen in FIG. 9A the teeth 410 have portions of the busbars 120 wrapped thereover to provide connection points for the lid. Either 410 or 416 may be switched for a sheetmetal clamp or clip assembly to ensure a good connection and engagement between the base 406 and the lid 404. Also, it may be noted that the busbars 120 from the panel laminate would be connectable to the element 410 to make the connection to the lid 404 as seen in FIG. 9B. Moreover, normal junction box connections to sheetmetal may be added in the base 406, with separate specific features to take the electrical connection to the lid elements. As such, it can be appreciated that various types of components can be used to connect the busbars 120 to the electronics in the lid 604, using any one or more components and/or the busbars themselves. [0046] FIG. 10 shows another base 406' that is similar to that shown in FIG. 9, but differently sized. The example in FIG. 10 also comprises portions of busbar 430 that wrap over the teeth 410'. In this way, the portions of busbar 430 are presented towards the mating lid 404 to enable the electronics 412 in that lid 404 to engage the busbars and make electrical connections.

[0047] FIG. 1 1 shows another representation of a base 506, wherein multiple busbars 520 are connected to a single "connector" 540, which will then mate with a matching connector in the lid (not shown). It can be understood that the shape of the connector 540 and mechanisms used for making electrical connections to the busbar terminals 520 can vary and FIG. 1 1 is only illustrative of one example. It can also be appreciated that in some configurations where some electronics are in the base 506 (e.g., diodes or MOSFETs), a similar configuration can be provided (not shown) where a 2-pole connector is provided for connecting to the lid.

[0048] FIG. 12 shows a representation of yet another junction box assembly 600 with a base 606 and lid 604 connected to each other, wherein the lid assembly 604 is larger in footprint than the base assembly 606. This may have several advantages in that a common base 606 may be used for multiple electronic configurations in the lid 604, but with a single process applied at the panel manufacturer up to the very last step of attaching the particular lid 604 to the junction box base 606. FIG. 12 is a partial cross-section to illustrate the interior of the junction box assembly 600 in which it can be seen that the busbars 620 wrap around the teeth 610 in the base 606, and that clips 622 or other connectors attached to the circuit board 612 engage the teeth 610 and thus the busbars 620. The lid 604 in this example includes a secondary lid 660 that enables the lid electronics 612 to be accessed, even when connected to the base 606. The above elements can also be seen in the exploded view shown in FIG. 13.

[0049] It can be appreciated that the electronic components and connection clips between 622 and 610 may be on either side of the circuit board 612. In FIGS. 12 and 13 the components are on the top side, and clips 622 are shown on the bottom. Components can easily be switched between top and bottom, and various configurations of the clips 622 can be configured to take the busbar teeth connections through the board to the opposite side for connection as well. Similarly, it may be noted that in a configuration that combines FIG. 12 and FIG. 1 1 with a single "connector", the mating connector may similarly be on either the top or bottom of the circuit board 612 in the lid 604. As indicated above, some electronics may still be placed in the base 606 with the balance in the lid 604. [0050] FIG. 14 shows a solid exterior view of the configuration shown in FIGS. 12 and 13, with the busbars 620 being visible from below, which would come from the panel into the junction box base 606.

[0051] FIG. 15 shows a variation of FIG. 15 wherein the base contains "fly-outs" 670 for the purposes of stability, additional mounting points for the lid 604, and maintaining a thermal gap between the back of the panel and the lid 604. FIG. 16A is similar to FIG. 15 but rotated to provide an additional view. FIG. 16B illustrates that the flyouts 670 can be joined, and can possess any desired shape and contour.

[0052] FIGS. 17-19 show a representation of a base 706 with connections (similar to what is shown in FIGS. 15 and 16), which connect to a lid 704 that has been overmolded over the electronics (not shown), and which therefore means that the lid's electronic assembly can be of various unique shapes, and can extend beyond the bounds of the base footprint. Similarly, the lid 704 in such a configuration can have other features such as cooling fins 780 (shown), etc., directly in contact with the electronics. That is, overmolding such as that illustrated in FIG. 17 can provide additional flexibility and features to the lid 704 while maintaining the serviceability and replaceability discussed herein.

[0053] For simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the examples described herein. However, it will be understood by those of ordinary skill in the art that the examples described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the examples described herein. Also, the description is not to be considered as limiting the scope of the examples described herein.

[0054] It will be appreciated that the examples and corresponding diagrams used herein are for illustrative purposes only. Different configurations and terminology can be used without departing from the principles expressed herein. For instance, components and modules can be added, deleted, modified, or arranged with differing connections without departing from these principles.

[0055] The steps or operations in the flow charts and diagrams described herein are just for example. There may be many variations to these steps or operations without departing from the principles discussed above. For instance, the steps may be performed in a differing order, or steps may be added, deleted, or modified. [0056] Although the above principles have been described with reference to certain specific examples, various modifications thereof will be apparent to those skilled in the art as outlined in the appended claims.