The present disclosure is directed generally to connectors for providing an electrical connection from foil or flat conductors to plug connectors able to receive cables or wires. In particular, the present disclosure is directed to a junction box for quick and efficient electrical connection to the foil or flat conductors of solar cells.
Solar cells convert light energy to electrical energy. Typically one or more solar cells are sandwiched between glass sheets or glass and laminate substrate to form a solar panel. Thin flat metal conductors or foil conductors emanating from the solar cells transport the generated electrical energy. The glass or laminate is provided with an access area or hole to allow the foil conductors to be connected to a junction box or other electrical connector. The junction box usually has contacts for providing electrical connection between the foil conductors and plug connectors which can receive wires or cable to permit connection to the solar cells. The plug connectors can permit quick, easy and efficient connection to other solar panels, batteries, inverters or power supply utilities.
Foil conductors are typically connected to the junction box by manual processes. Installation of junction boxes to solar panels via automation is inhibited by the varying configurations of solar panel design and in particular the manner in which access is provided to the foil conductors of the solar panel. In addition to this shortcoming, servicing junction boxes which contain electrical components such as diodes and terminals can be difficult since junction boxes are typically located in hard to access areas of the solar panels which are also typically located in hard to access areas, e.g. roofs. Also, current junction boxes may not be able to accommodate increases in electrical current as the efficiency of energy conversion of solar panels increases.
Junction boxes according to the present disclosure can permit automated mounting to a solar panel and connection to the foil conductors thereof. Junction boxes disclosed herein may also facilitate servicing and/or replacement of electrical components housed therein. Also in keeping with the present disclosure, junction boxes may accommodate higher currents for use with solar panels having increased efficiency.
In one aspect of the present disclosure, a solar panel junction box is provided comprising a base module and a cover module. The base module has a generally flat bottom wall with an outer bottom surface and an inner top surface. The bottom wall includes a cut-out portion and a plurality of terminals mounted to the inner top surface of the bottom wall. Each terminal has one end with a solder terminal extending over the cut-out portion and an opposite end has clip terminals extending upward from the inner top surface. The base portion includes an upstanding base peripheral wall adapted to nestingly mate with an upstanding cover peripheral wall. The cover module includes a generally flat top wall with an outer top surface and an inner bottom surface. The cover module includes an upstanding cover peripheral wall adapted to nestingly mate with the upstanding base peripheral wall and a plurality of main component terminals secured, in parallel orientation to each other, to the inner bottom surface. The plurality of main component terminals includes a pair of outer main component terminals and a pair of inner main component terminals. Each of the main component terminals has a generally rectangular configuration with a first end and a second end and an intermediate portion. Each intermediate portion comprises a generally flat rectangular terminal secured to the inner bottom surface and has a connection tab extending perpendicular from the inner bottom surface for connection to a respective one of the clip terminals. The first end of each outer main component terminal and the first end of each inner main component terminal includes a raised tail portion providing a plurality of axially aligned contact retaining channels. The pair of inner main component terminals each has an opposite raised tail portion at its second end providing a pair of axially aligned contact retaining channels. A first diode connected between the axially aligned contact retaining channels of the first end of one of the outer main component terminals and the first end of the inner terminal adjacent thereto. A second diode is connected between the axially aligned contact retaining channels of the first end of the other outer main component terminal and the first end of the inner terminal adjacent thereto. A third diode is connected between the axially aligned contact retaining channels of the second end of the inner main component terminals. The second end of each outer main component terminal includes an upstanding cable connection terminal. The upstanding cover peripheral wall includes a pair of cable access openings positioned adjacent the respective cable connection terminals to facilitate electrical cable connection to the cable connection terminals.
In another aspect of the present disclosure, a solar panel junction box is provided comprising a base module and a cover module. The base module has a generally flat bottom wall with an outer bottom surface and an inner top surface. The bottom wall includes a cut-out portion and a plurality of terminals mounted to the inner top surface of the bottom wall. Each terminal has one end with a solder terminal extending over the cut-out portion and an opposite end has clip terminals extending upward from the inner top surface. The base module includes an upstanding base peripheral wall adapted to nestingly mate with an upstanding cover peripheral wall. The base module has a flanged skirt portion extending circumferentially outward from the upstanding peripheral wall in generally coplanar relationship to the bottom wall a distance at least as great as the height of the peripheral wall. The cover module includes a generally flat top wall with an outer top surface and an inner bottom surface. The cover module includes an upstanding cover peripheral wall adapted to nestingly mate with the upstanding base peripheral wall and a plurality of main component terminals secured to said inner bottom surface. The plurality of main component terminals includes a pair of outer main component terminals and a pair of inner main component terminals. Each of the main component terminals has a connection tab extending perpendicular from the inner bottom surface for connection to a respective one of the clip terminals. A plurality of diodes serially connects the main component terminals within the cover module. Each outer main component terminal includes an upstanding cable connection terminal. The upstanding cover peripheral wall includes a pair of cable access openings positioned adjacent the respective cable connection terminals to facilitate electrical cable connection to the cable connection terminals.
Other aspects, objects and advantages of the present disclosure will be understood from the following description according to the illustrated embodiments of the present disclosure, specifically including stated and unstated combinations of the various features which are described herein and relevant information which is shown in the accompanying drawings and examples.
In the following detailed description, reference will frequently be made to the following views of the drawing, in which like reference numerals refer to like components, and in which:
It is to be understood that the disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the inventive features herein disclosed in virtually any appropriate manner and combination.
One embodiment of base portion 18 is shown in
Base wall 26 can have cutout 36 to allow one or more contacts 22 to access exposed ends 17 of foil conductors 16 (see
Contact 22 can be secured to top or inner surface 27 of base wall 26 such that contact pad portion 46 of each contact 22 is aligned in an overlaying fashion with a respective exposed end 17 when base portion 18 is secured to panel 12. Each retainer arm 52, 54 can be received in respective mounting wall 58, 60 through a friction or interference fit with the use of barbs or hooks for biting into one or more of mounting walls 58, 60. Platform portions 54, 56 cooperate with mounting walls 58, 60 to prevent side-to-side and forward and back rotation of contacts 22. Alternatively, heat staking can also be used to secure contacts 22 to base wall 26.
In one embodiment, base wall 26 can have protective walls 61 surrounding the exposed sides of spring clips 48. Protective walls 61 can extend vertically and generally perpendicular from inner surface 27 to at least the height extent of spring clips 48 as shown in
To secure contact between contact pad portion 46 and exposed end 17, solder charge layer 64 can be pre-applied to bottom side of contact pad portion 46 as shown in
As shown in
Base portion 18 can be secured to solar panel 12 by commonly known methods, for example adhesive bonding. In one embodiment, double sided tape 66 can be applied to underside surface 62 of base wall 26 as shown in
To assist in urging base portion 18 against solar panel 12, base wall 26 can have bulk wall 68 extending upwards and generally perpendicularly from inner surface 27 and beyond spring clips 48. Top end of bulk wall 68 can be generally coplanar with top surface 70 of upstanding wall 28 as shown in
In another embodiment shown in
A seal protecting the enclosure formed by the mating of base and cover portions 18, 20 can be provided on either base portion 18 or cover portion 20 since junction boxes are typically exposed to outdoor environment. In the embodiment shown in
The rise and fall of temperatures can create stress on a junction box. For example, heating during daytime hours can cause air within a junction box to expand which can compromise a seal, if any, between base and cover portions. Similarly, cooling during nighttime hours can cause air inside a junction box to contract which can also compromise a seal and allow air and moisture to enter. Excessive moisture in junction box can cause the junction box to malfunction and/or fail. Allowing the pressure in a junction box to equalize without allowing moisture to enter the junction box can extend the life of the seal and the operability of the junction box.
In one embodiment, junction box 10 can have a pressure equalization hole to allow air to pass in and out of junction box 10. In the embodiment shown in
To pass the electrical energy from bottom portion 18 to cover portion 20 of junction box 10, cover portion 20 can have one or more main component terminals for connecting to the one or more contacts 22 of bottom portion 18. Several factors can influence the number and configuration of the terminals such as the voltage carried by the terminals and the number of foil conductors and the attendant heat generated by the terminals and/or other electrical components in the junction box. As junction box 10 can be used to connect two or more solar panels together in series, the terminals can be made to accept the cumulative electrical voltage generated by the connected solar panels. The greater the voltage and/or current carried by the terminals the greater the amount of heat generated. This heat can cause failure of one or more components of the junction box 10 such as the walls of the junction box, the terminals and/or electrical components such as wire bridges or diodes. Accordingly, the terminals can be sized and arranged to enhance heat dissipation.
In the embodiment shown in
As shown in
Inner terminals 102 can have opposing front and rear ends 122, 124. Each front and rear end 122, 124 can have raised retention channels 126. Intermediate section 128 can have front and rear flat plates 130, 132 partially separated by connecting tab 134 extending vertically and generally perpendicular to front and rear plates 130, 132.
Outer and inner terminals 102, 104 can be made of any conductive material such as metal and metal alloys. In one embodiment, outer and inner terminals 102, 104 can be made of a high conductivity, high copper alloy. Terminals 102, 104 also can be plated with one or more metal and metal alloys. In one embodiment, terminals 102, 104 can be made of high copper alloy K65 by Wieland and have nickel plating throughout. Retention channels 112, 126 and cable connection members 120 can have additional tin plating. Connecting tabs 116, 134 can have additional silver plating. Terminals 102, 104 can be formed via known stamping processes.
Each terminal 102, 104 can be secured to inner surface 81 of top wall 80. In one embodiment, terminals 102, 104 can be secured to inner surface 81 so that all the flat portions of terminals 102, 104 contact inner surface 81 to enhance heat dissipation. Terminals 102, 104 can have two or more holes 136 which mate with posts 138 extending from inner surface 81 and heat staked in place. Alternative methods to secure terminals to cover portion can be used.
Safety standards can regulate the distance terminals should be space apart from each other depending on the voltage carried as a precaution against arcing between terminals. These standards compete with the desirability of compact junction boxes. For terminals carrying 1000 volts DC but subjected to an 8000 volt DC impulse, it is recommended that terminals be spaced about ten millimeters in terms of total length along a dielectric surface. For example, while terminals may be separated by a certain distance in terms of a straight line extending between two points along a flat surface, this distance can be increased without additional spacing of the terminals by adding raised surfaces therebetween since total distance along an uneven surface is greater than similarly spaced terminals on a flat surface.
In one embodiment, cover portion 20 can have barrier walls 144, 146 and 148 extending vertically and generally perpendicular from inner surface 81 and between terminals 102, 104 as shown in
Each connecting tab 116, 134 of terminals 102, 104, respectively connect to spring clips 48 of each contact 22 when base and cover portions 18, 20 are brought together to electrically connect base and cover portions 18, 20. This is shown in
Terminals 102, 104 can be electrically connected in series or parallel to each other by any number of electrical components. In one embodiment, front retention channel 112 of each outer terminal 102 can be axially aligned with front retention channel 126 of its respective adjacent inner terminal 104 for receiving respective ends of an electrical component to electrically connect outer terminals 102 to their respective adjacent inner terminals 104. The serial connection of terminals 102, 104 can be completed by having rear retention channels 126 of inner terminals 104 axially aligned for receiving respective ends of an electrical component to electrically connect inner terminals 104 to each other. In this manner, terminals 102, 104 can be connected in series by having outer terminal 102 electrically connected to its respective adjacent inner terminal 104 which can be electrically connected to adjacent inner terminal 104 which can be electrically connected to its respective adjacent outer terminal 102.
The particular electrical component electrically connecting terminals 102, 104 can vary depending on the voltage and current carried by terminals 102, 104. Typically for twenty four volts DC or less a simple wire bridge can be used. A wire bridge however can transmit electricity in either direction. This can allow electrical energy to flow from a power supply which the solar panels are connected to, such as a battery or electrical utility line, to flow to the solar panels. In one embodiment, diodes 142 electrically connect terminals 102, 104. Diode 142 can allow electricity to flow substantially in one direction only, thus inhibiting flow from a power supply back to the solar panels. For a junction box that can handle 1000 volts DC, diodes 142 can be selected to accept about a nine amp current. A nine amp current flow through diodes 142 can result in overheating and failure if the heat generated by diodes 142 cannot be removed or dissipated.
The heat sink characteristics of terminals 102, 104 can dissipate the heat generated by diodes 142 in typical operating outdoor climates and prevent diodes 142 from reaching the recommended maximum temperature of about 200° Celsius. In one embodiment, the total surface area of outer and inner terminals 102, 104 in contact with inner surface 81 of cover 20 can be about 15 cm2 and the total surface area of top wall 80 can be about 65 cm2. Actual dimensions of these embodiments of terminals 102, 104 and top wall 80 are shown in
As shown in
To transmit the electricity out of junction box 10, each outer terminal 102 can have cage clamp 140 connected to cable connection tab 120 to permit quick and easy connection of outer terminals 102 with the conductor portion of a wire or cable. To allow entry of wires or cables which connect to outer terminals 102, cover portion 20 can have access apertures 162 passing through raised wall 82 adjacent each cable connection tab 120. Extending out and about each access aperture 162 can be cable sleeve 164 having strain relief fingers 166 at terminal end thereof. As shown in
A collar 166 can be inserted into each cable sleeves 164 to reside inside strain relief fingers 166. (See
While the present disclosure has been described in detail with reference to the foregoing embodiments, other changes and modifications may still be made without departing from the spirit or scope of the present disclosure. It is understood that the present disclosure is not to be limited by the embodiments described herein. Indeed, the true measure of the scope of the present disclosure is defined by the appended claims including the full range of equivalents given to each element of each claim.
This application is a continuation-in-part of U.S. patent application Ser. No. 12/148,088 filed on Apr. 16, 2008 which is incorporated herein by reference, and also claims the benefit of U.S. Provisional Patent Application Ser. No. 61/154,289 filed on Feb. 20, 2009, which is incorporated herein by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/US09/40843 | 4/16/2009 | WO | 00 | 12/13/2010 |
Number | Date | Country | |
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61154289 | Feb 2009 | US |
Number | Date | Country | |
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Parent | 12148088 | Apr 2008 | US |
Child | 12988411 | US |