Low profile photovoltaic (LPPV) box

A low profile photovoltaic connection system for placement in space restricted areas. The connection system includes a connection box, diodes, and heat sinks inside of the connection box. The heat sink element is maintained in contact with the diode element such that the heat sink dissipates heat externally of the junction box and the contacts are arranged with a flat surface parallel to the solar panel to reduce vertical elevation of the junction box when mounted to the solar panel.

FIELD OF THE INVENTION

The present invention is directed to a connection system for photovoltaic (PV) arrays, and more particularly to a low profile connection box in a PV connection system that provides a solution for space restricted areas.

BACKGROUND OF THE INVENTION

Photovoltaic (PV) modules, or PV arrays, produce electricity from solar energy. Electrical power produced by PV modules reduces the amount of energy required from non-renewable resources such as fossil fuels and nuclear energy. Significant environmental benefits are also realized from solar energy production, for example, reduction in air pollution from burning fossil fuels, reduction in water and land use from power generation plants, and reduction in the storage of waste byproducts. Solar energy produces no noise, and has few moving components. Because of their reliability, PV modules also reduce the cost of residential and commercial power to consumers.

PV cells are essentially large-area semiconductor diodes. Due to the photovoltaic effect, the energy of photons is converted into electrical power within a PV cell when the PV cell is irradiated by a light source such as sunlight. PV cells are typically interconnected into solar modules that have power ranges of up to 100 watts or greater. For large PV systems, special PV modules are produced with typical power range of up to several 100 W. A photovoltaic module is the basic element of a photovoltaic power generation system. A PV module has many solar cells interconnected in series or parallel, according to the desired voltage and current parameters. PV cells are connected and placed between a polyvinyl plate on the bottom and a tempered glass on the top. PV cells are interconnected with thin contacts on the upper side of the semiconductor material. The typical crystalline modules power ranges from several W to up to 200 W/module.

In the case of facade or roof systems, the photovoltaic system may be installed during construction, or added to the building after it is built. Roof systems are generally lower powered systems, e.g., 10 kW, to meet typical residential loads. Roof integrated photovoltaic systems may consist of different module types, such as crystalline and micro-perforated amorphous modules. Roof-integrated photovoltaic systems are integrated into the roof, such that the entire roof or a portion thereof is covered with photovoltaic modules, or they are added to the roof later. PV cells may be integrated with roof tiles or shingles.

PV modules/arrays require specially designed devices adapted for interconnecting the various PV modules/arrays with each other, and with electrical power distribution systems. PV connection systems are used to accommodate serial and parallel connection of PV arrays. In addition to connection boxes, a PV connection system includes connectors that allow for speedy field installation or high-speed manufacture of made-to-length cable assemblies. Connection or connection boxes may be required to receive specialized cable terminations from PV modules/arrays, with power diodes inside for controlling current flow to the load. PV arrays may be required in areas with tight space restraints and requirements, requiring the size of the PV module to be minimized.

Therefore, there is a need for a low profile PV (LPPV) box that allows for the placement of PV arrays in compact areas.

SUMMARY OF THE INVENTION

The present invention is directed to a low profile PV junction box for distributing solar energy captured by the PV arrays in the solar system. The junction box has a cover portion with an opening for receiving at least one foil contact from a solar panel, a plurality of diode elements, each having a heat sink element attached for dissipating heat generated by the diode elements and a plurality of contacts configured to electrically connect to at least one foil contact from a solar panel, and a plurality of cables configured to interconnect a plurality of low profile junction boxes, and configured to conduct the energy from the solar panels. The heat sink elements are in contact with the diode elements, such that the heat sinks dissipate heat externally of the junction box and wherein the contacts are arranged with a flat surface parallel to the solar panel to reduce vertical elevation of the junction box when mounted to the solar panel.

Another embodiment of the present invention includes a low profile junction box for interconnection of solar cell arrays in a power distribution system. The junction box has a cover portion with an opening for receiving at least one foil contact from a solar panel, a diode element with a heat sink element for dissipating heat generated by the diode elements and a plurality of contacts to electrically connect to at least one foil contact from a solar panel. The junction box also has a plurality of cables to interconnect a plurality of low profile junction boxes, and to conduct the energy from the solar panels. The heat sink element is in contact with the diode element, such that the heat sink dissipates heat externally of the junction box and wherein the contacts are arranged with a flat surface parallel to the solar panel to reduce vertical elevation of the junction box when mounted to the solar panel.

An advantage of the present invention is that the low profile PV junction box allows the PV solar array to be placed in space-restricted areas.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a low profile PV junction box for interconnection of solar cell arrays.FIGS. 1-3illustrate the two-position embodiment of the present invention. The junction box module10is mounted to the backside of a solar panel (not shown) and connected to the foil contacts of the solar panel to distribute energy captured by the panel. The two-position module10has a cover portion30, two contacts12and cable assembly16. The module10is mounted to the backside of the panel and the conductive foils from the panel are soldered or otherwise attached to the contacts12of the module10. The contacts are disposed horizontally in the junction box such that when applied to the solar panel, they are parallel to the conductive foils of the panel. The arrangement of the horizontal contacts allows the junction box to have a minimum vertical profile and conform to smaller spaces. A waterproof epoxy or adhesive, such as RTV silicon, is used to secure the module to the panel. The centerline spacing between the contacts12in the two-position module10is approximately 18.00 mm, however, any suitable spacing may be used.

FIGS. 4 and 5illustrate the three-position module18of the present invention. The module18is mounted to the backside of a solar panel (not shown) to distribute energy captured by the panel. The three-position module18has a cover portion30, three contacts20, diodes22and cable assembly24. The module18is mounted to the backside of the panel and similar to the two-position module10, the conductive foils from the panel are soldered or otherwise attached to the contacts20of the three-position module. A waterproof epoxy or adhesive, such as RTV silicon, is used to secure the module to the panel. In the embodiment shown, the centerline spacing between the contacts in the three-position module18is approximately 36.00 mm, however, any suitable spacing may be used.

Both the two position and three position modules10,18have an overmolded cover portion30that protects and covers the circuitry (diodes, contacts and cable ends). The cover portion16can be constructed of a substantially rigid, electrical insulating material, such as an ABS plastic or other suitable material. The junction box/cover material preferably has high thermal conductivity.

The diode circuitry used with the present invention can be TO-220 packaged diodes14,22. The TO-220 packaged diodes14,22contain heat sinks that assist with dissipating heat and help to meet the temperature standard of IEC 61215 (Ed. 2) or other applicable industry standards. The present invention may also use ITO-220 diodes that have plastic covered heat sinks and help to dissipate any generated heat to meet the temperature standard. In addition to the TO-220 diode and ITO-220 diode, any other similar and suitable diode that can meet the temperature standard may be used with the present invention.

The present invention is designed to withstand an operating current of a 10 amp to 15-amp range, and a diode operating voltage of about 45 VDC maximum. The ambient operating temperature the module can withstand is −40 degrees to 75 degrees Celsius. In addition, the contacts12,20are preferably tin plated phos bronze, however any suitable materials may be used, such as brass, or other types of copper alloys. The contacts12,20may also be a unitary configuration with the heat sink as well.