Patent Application
20120211058
The invention relates to solar panels and, in particular, to an antenna for a wireless element affixed to a solar panels to enhance the communication range of the wireless element.
A solar panel, also referred to as a photovoltaic panel, a solar module, or a photovoltaic module, is a packaged interconnected assembly of solar cells (also referred to as “solar wafers” or “photovoltaic cells”).
Solar panels use light energy (photons) from the sun to generate electricity through photovoltaic effect (i.e., the photo-electric effect). Because a single solar panel can only produce a limited amount of power, most photovoltaic installations involve connecting multiple solar panels into an array. A photovoltaic system or a solar system typically includes an array of solar panels, an inverter, batteries and interconnection wiring. Solar panels are interconnected, in series or parallel, or both, to create a solar array providing the desired peak output voltage and output current. More specifically, solar cells in a solar panel are connected in series to create an additive voltage and connected in parallel to yield a higher current.
Once the solar cells are assembled into a panel, there is limited access to identify or monitor the individual solar cells. Should any one cell in a solar panel malfunctions, or any one solar panel in a solar array malfunctions, and there will be a claim of warranty replacement or repair by user, but solar panel suppliers have only limited ability to monitor the output performance of the solar cells or solar panels throughout their operational life, in order to validate the warranty claim. This makes product failure analysis and quality correlation study difficult and economically challenging. Inability to remotely monitor individual solar cell or individual solar panel often leads to excess cost over the life time of the panel, also requires more labor maintenance or repairing or expensive replacement.
According to one embodiment of the present invention, a solar panel including an array of interconnected photovoltaic cells formed between a top plate and a back sheet and secured by a metal frame includes a wireless device attached to or embedded in the solar panel where the wireless device includes a wireless communication interface and a memory; and an antenna formed on the metal frame of the solar panel where the antenna is electrically connected to the wireless device to extend a communication range of the wireless device.
According to another embodiment of the present invention, a solar panel including an array of interconnected photovoltaic cells formed between a top plate and a back sheet and secured by a metal frame includes a wireless device attached to or embedded in the solar panel where the wireless device comprising a wireless communication interface and a memory; and an antenna formed attached to a junction box of the solar panel where the junction box houses electrical connections between electrical contacts of the photovoltaic cells to cable connectors in the junction box. The antenna is electrically connected to the wireless device to extend a communication range of the wireless device.
The present invention is better understood upon consideration of the detailed description below and the accompanying drawings.
a) illustrates a conventional solar panel including an assembly of solar cells interconnected in a two-dimensional array.
b) illustrates a conventional single solar cell including two bus bars forming the electrical contacts of the solar cell.
In accordance with the principles of the present invention, an antenna structure, including a slot antenna and a patch antenna, is formed on a solar panel to enhance the communication range of a wireless device affixed to the solar panel. In some embodiments, the slot antenna or patch antenna is formed on the metal frame of the solar panel. In other embodiments, the slot antenna or patch antenna is formed on a conductive layer affixed to the junction box of the solar panel. The antenna structure enables the wireless device to extend the wireless device's communication range so that the wireless device may communicate with a wireless reader at a greater distance.
In the present description, a solar panel or solar module refers to an assembly of solar cells (or photovoltaic cells or solar wafers) for generating electricity through photovoltaic effect. In general, a solar panel includes an optically transparent layer on the front (sun up) side (also referred to as a “top plate”), allowing light to pass while protecting the solar wafers from the elements (rain, hail, etc.). The solar panel may also include a backside support (also referred to as the “back sheet”), typically made of plastic, such as polyethylene terephthalate (PET) or polycarbonate or other plastic materials. The top plate and the back sheet are secured in a metal frame, such as an aluminum alloy frame. The metal frame seals and protects the peripheral of the solar panel structure as well as provides mechanical supports for installation. A solar panel also includes a junction box for housing the electrical connections from the electrical contacts of the solar cells to the cable connectors in the junction box for electrical connection out of the panel. More specifically, the junction box houses the electrical connectors to the anode and cathode terminals of the solar panel.
In many applications, a wireless device for tracking, authenticating, or performance monitoring, is attached to or embedded in a solar panel for providing remote tracking and/or performance monitoring of the solar panel. Embedding a wireless device in a solar panel for tracking and/or performance monitoring is described in copending and commonly assigned U.S. patent application Ser. No. 12/896,687, filed Oct. 1, 2010, having at least one common inventor hereof, which patent application is incorporated herein by reference in its entirety. In the '687 patent application, the wireless device can be a wireless tracking device for providing tracking function or a wireless tracking and monitoring device for providing both tracking and performance monitoring functions.
To facilitate tracking, authentication, or performance monitoring of the solar panel, a wireless device 15 is attached to or embedded in the solar panel 10 to enable wireless communication with a wireless reader device 20. In some embodiments, the wireless device 15 may be embedded in the solar panel, such as embedded between the top plate and the back sheet of the solar panel. The wireless device 15 may also be formed embedded inside the back sheet. In other embodiments, the wireless device 15 may be affixed or attached to the exposed side of the back sheet of the solar panel 10. When formed on the exposed back sheet of the solar panel, the wireless device 15 may be encapsulated by a protective encapsulant layer. Alternately, the wireless device 15 may be formed inside the junction box 18 of the solar panel. Other ways to incorporate the wireless device 15 into a solar panel are possible. The exact method of integrating the wireless device 15 into the solar panel 10 is not critical to the practice of the present invention.
In embodiments of the present invention, the wireless device includes a memory for storing the identification or identity information of the solar panel or the identification or identity information of the individual solar cells forming the panel. The wireless device further includes wireless communication circuitry for facilitating wireless communication, such as using radio frequency (RF). The wireless device may further include a controller or processor for controlling the operation of the wireless device. When the wireless device also performs monitoring functions, the wireless device includes circuitry to measure one or more operational parameters associated with the solar panel or the solar cells. The measured performance data can be stored in the memory of the wireless device.
However, the solar panel contains many conductive and dielectric materials which can adversely interfere with the wireless device's operation and hinder the performance of the wireless device. More specifically, the communication range of the wireless device can become limited in the presence of these conductive and dielectric materials. In some cases, the wireless device cannot even achieve the as-designed communication distance.
In embodiments of the present invention, an antenna structure is formed on the solar panel to extend the communication range of a wireless device attached to or embedded in the solar panel. The antenna structure enables the wireless device to overcome interferences from the conductive and dielectric materials formed as part of the solar panel. The wireless device is therefore able to maintain at least the as-designed wireless communication range. In some cases, the wireless communication range can be increased beyond the as-designed communication range.
Slot Antenna
In embodiments of the present invention, a slot antenna is formed on the metal frame of a solar panel and electrically connected to a wireless device attached to or embedded in the solar panel so that the slot antenna extends the communication range of the wireless device.
Slot antenna 60 further includes antenna terminals 62, 63 which are electrically connected to a wireless device 55 to enhance the communication range of the wireless device. In the present embodiment, the antenna terminals 62, 63 are connected to the mid-points at opposite sides along the length L of the cut-out of the slot antenna. In other embodiments, the antenna terminals 62, 63 can both be connected to the same end of the slot antenna. The placement of the antenna terminals is a function of the length of the slot antenna. As thus formed, the slot antenna 60 has an omnidirectional radiation pattern.
In
According to embodiments of the present invention, a slot antenna is formed on a metal layer affixed to the junction box of the solar panel.
Slot antenna 80 further includes antenna terminals 82 and 83 which are electrically connected to a wireless device 75 to enhance the communication range of the wireless device. In the present embodiment, the antenna terminals 82, 83 are connected to the mid-points at opposite sides along the length L of the cut-out of the slot antenna. In other embodiments, the antenna terminals 82, 83 can both be connected to the same end of the slot antenna. The placement of the antenna terminals is a function of the length of the slot antenna. As thus formed, the slot antenna 80 has an omnidirectional radiation pattern. As described above, the wireless device 75 may be affixed to or embedded in the solar panel to which the junction box 78 is attached. Electrical connections from the slot antenna 80 to the wireless device 75 can be accomplished using metal wires or metal strips or conductive cables. Various methods for forming the electrical connection between the slot antenna 80 and the wireless device 75 can be used. As described above, the wireless device 75 may be attached to the solar panel or embedded in the solar panel.
In embodiments of the present invention, the slot antenna 80 may be encapsulated by an encapsulant to protect the slot antenna. When the slot antenna 80 is encapsulated, the length of the slot antenna can be reduced by a factor of square root of the encapsulant's permittivity.
Patch Antenna
In embodiments of the present invention, a microstrip or patch antenna is formed on the metal frame of a solar panel and electrically connected to a wireless device attached to or embedded in the solar panel so that the patch antenna extends the communication range of the wireless device. In the present description, a patch antenna refers to an antenna formed using a patch of a conductive metal, which is one-half wavelength long, mounted a precise distance above a larger ground plane. In some cases, a spacer made of a dielectric material is placed between the patch and the ground plane.
In some embodiments, the conductive metal thin film is copper or aluminum or other high conductivity metals. The patch 122 has a length L being half of the wavelength of the operational frequency used in the wireless communication of the wireless device. The dielectric layer 124 has a permittivity ∈r and a thickness being a small fraction of the operational wavelength of the wireless communication and a function of the operational frequency. The greater the operational frequency, the thinner the dielectric layer is. Typically, the dielectric layer 124 has width and length greater than the area of the patch 122.
A microstrip transmission line 125 extends from an edge of the patch metal 122 to form an antenna terminal 112. The other antenna terminal 113 is formed from the ground plane of the metal frame 107. The antenna terminals 112 and 113 are electrically connected to a wireless device 105 to enhance the communication range of the wireless device. Electrical connections from the patch antenna 110 to the wireless device 105 can be accomplished using metal wires or metal strips or conductive cables. Various methods for forming the electrical connection between the patch antenna 110 and the wireless device 105 can be used.
According to embodiments of the present invention, a patch antenna is formed on a metal layer affixed to the junction box of the solar panel.
In some embodiments, the conductive metal thin film forming the patch 162 is copper or aluminum or other high conductivity metals. The patch 162 has a length L being half of the wavelength of the operational frequency used in the wireless communication of the wireless device. The dielectric layer 164 has a permittivity ∈r and a thickness being a small fraction of the operational wavelength of the wireless communication and a function of the operational frequency, as described above. The dielectric layer 164 has width and length greater than the area of the patch 162.
A microstrip transmission line 155 extends from an edge of the patch metal 162 to form an antenna terminal 152. The other antenna terminal 153 is formed from the metal layer 161 being the ground plane. The antenna terminals 152 and 153 are electrically connected to a wireless device 135 to enhance the communication range of the wireless device. Electrical connections from the patch antenna 150 to the wireless device 135 can be accomplished using metal wires or metal strips or conductive cables. Various methods for forming the electrical connection between the patch antenna 150 and the wireless device 135 can be used. As described above, the wireless device 75 may be attached to the solar panel or embedded in the solar panel.
In embodiments of the present invention, the slot antenna 150 may be encapsulated by an encapsulant to protect the patch antenna.
The above detailed descriptions are provided to illustrate specific embodiments of the present invention and are not intended to be limiting. Numerous modifications and variations within the scope of the present invention are possible. The present invention is defined by the appended claims.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/444,685, filed on Feb. 18, 2011, which application is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61444685 | Feb 2011 | US |
