Cross-Reference to Related Applications

This application claims priority under 35 U.S.C. § 1 19(e) to each of U.S.S.N.

61/845,776, filed July 12, 2013, and entitled "Photovoltaic Cells, Systems, Components and Methods," U.S.S.N. 61/931,494, filed January 24, 2014, and entitled "Hybrid Photovoltaic Systems," and U.S.S.N. 61/949,913, filed March 7, 2014, and entitled "Photovoltaic Powered Door Lock." The entire contents of each of these applications is incorporated by reference herein.

Field

The disclosure generally relates to photovoltaic systems, cells, components and methods.

Background

Photovoltaic cells convert light into electrical energy.

Summary

This disclosure is based on the discovery that, by incorporating different types of photovoltaic cells having different conversion efficiencies under different irradiation conditions, one can obtain a photovoltaic system providing maximized power output under different irradiation conditions (e.g., in an overcast or foggy day). Such a photovoltaic system (e.g., containing both dye-sensitized photovoltaic cells and silicon photovoltaic cells) can have a superior power output compared to a photovoltaic system that contains only one type of photovoltaic cells (e.g., silicon photovoltaic cells).

In one aspect, this disclosure features a system that include a first plurality of photovoltaic cells; and a second plurality of photovoltaic cells electrically connected with the first plurality of photovoltaic cells. The first and second pluralities of photovoltaic cells are of different types. The system is configured to provide maximized power output under different light conditions.

Various embodiments are disclosed herein. It is understood that such embodiments are only exemplary in nature. It is also understood that aspects of the embodiments can be combined in various manners as appropriate. Description of Drawings

Embodiments of the disclosure are described below with the aid of drawings, in which:

FIG. 1 is a graph showing the current output produced by a dye-sensitized

photovoltaic cell and a silicon photovoltaic cell on a cloudy day;

Fig. 2 is a graph showing the cumulative energy produced by the dye-sensitized photovoltaic cell and the silicon photovoltaic cell shown in FIG. 1 ; and

Fig. 3 is a graph showing the cumulative energy produced by a dye-sensitized photovoltaic cell and a silicon photovoltaic cell on a mixed day.

Detailed Description

In general, this disclosure relates to a system including at least two (e.g., two, three, or four) different types of photovoltaic cells electrically connected together. The system is configured to provide maximized power output under different light conditions.

In some embodiments, the system can include a first plurality of photovoltaic cells, and

a second plurality of photovoltaic cells electrically connected with the first plurality of photovoltaic cells, where the first and second pluralities of photovoltaic cells are of different types. In some embodiments, the first plurality of photovoltaic cells can include dye sensitized photovoltaic cells. In such embodiments, the second plurality of photovoltaic cells can include photovoltaic cells other than dye sensitized photovoltaic cells, such as amorphous silicon photovoltaic cells, monocrystalline silicon photovoltaic cells, polycrystalline silicon photovoltaic cells, cadmium selenide photovoltaic cells, cadmium telluride photovoltaic cells, copper indium selenide photovoltaic cells, or copper indium gallium selenide photovoltaic cells.

In some embodiments, the first plurality of photovoltaic cells can be disposed in a first array, and the second plurality of photovoltaic cells can be disposed in a second array different from the first array. In each of the first and second arrays, the photovoltaic cells can be electrically connected in series, in parallel, or in combination thereof. The first and second arrays are electrically coupled with a charge controller device capable of combining the power output of the first and second arrays. The charge controller device can be electrically coupled to an external load (e.g., a battery or a motor) to provide electrical energy obtained from the photovoltaic cells to the external load. Without wishing to be bound by theory, it is believed that such a system can provide maximized power output at different irradiation conditions, thereby improving overall conversion efficiency of the system and providing an improved user experience. Such a system is particularly advantageous in areas where there are typically more cloudy days than sunny days or in areas that do not face direct sunlight. For example, when the first and second pluralities of photovoltaic cells are dye-sensitized photovoltaic cells and amorphous silicon photovoltaic cells, respectively, the dye-sensitized photovoltaic cells have a lower conversion efficiency at high light levels than amorphous silicon photovoltaic cells, but higher conversion efficiency at low light levels than amorphous silicon photovoltaic cells. The charge controller device can combine the power output generated by the first and second pluralities of photovoltaic cells and provide it to an external load. Thus, without wishing to be bound by theory, it is believed that such a photovoltaic system can provide sufficiently high power output in days or periods when the light level is low (e.g., in an overcast or foggy day).

In some embodiments, the first and second pluralities of photovoltaic cells can be disposed on a single array (e.g., the first array). For example, the first plurality of photovoltaic cells can be arranged (e.g., electrically connected in series, in parallel, or in combination thereof) in a first segment of the first array and the second plurality of photovoltaic cells can be arranged (e.g., electrically connected in series, in parallel, or in combination thereof) in a second segment of the first array that is different from the first segment.

In some embodiments, the cells in the first segment as a whole are electrically connected to the cells in the second segment as a whole in parallel. In such embodiments, the system can further include a voltage boosting device electrically coupled to the first and second pluralities of photovoltaic cells. The voltage boosting device can be capable of increasing a lower voltage produced by one of the first and second pluralities of photovoltaic cells to match a higher voltage produced by the other of the first and second pluralities of photovoltaic cells. For example, the first and second pluralities of photovoltaic cells can be dye-sensitized photovoltaic cells and amorphous silicon photovoltaic cells, respectively. Under strong light conditions, the dye-sensitized photovoltaic cells can produce a lower voltage (e.g., 1 V) than that (e.g., 12 V) produced by amorphous silicon photovoltaic cells. The voltage boosting device can increase the voltage produced by the dye-sensitized photovoltaic cells to match that of the amorphous silicon photovoltaic cells to prevent current generated from one type of cells flowing into the other type of cells, which would result in loss of energy (e.g., in the form of heat) and reduce overall conversion efficiency of the system. As another example, under low light conditions, the dye-sensitized photovoltaic cells can produce a higher voltage (e.g., 1 V) than that (e.g., 0.1 V) produced by amorphous silicon photovoltaic cells. The voltage boosting device can increase the voltage produced by the amorphous silicon photovoltaic cells to match that of the dye-sensitized photovoltaic cells to prevent waste of energy produced by the cells.

In some embodiments, the voltage boosting device can be a Texas Instruments BQ25504 ultra-low power boost converter. Other examples of voltage boosting devices include the Maxim max 17710, the Linear Technologies LTC3105, and the Fujitsu

MB39C831.

In some embodiments, the photovoltaic cells in the first segment as a whole are electrically connected to the cells in the second segment as a whole in series. In such embodiments, the first and second pluralities of photovoltaic cells can be modulated such that they produce substantially the same current to minimize waste of energy produced by the cells. For example, the first and second pluralities of photovoltaic cells can be dye-sensitized photovoltaic cells and amorphous silicon photovoltaic cells, respectively. Under strong light conditions, the dye-sensitized photovoltaic cells typically produce a lower current than that produced by the amorphous silicon photovoltaic cells having the same exposure area. In such embodiments, the exposure area of the amorphous silicon photovoltaic cells can be reduced or a light filter can be used to cover the amorphous silicon photovoltaic cells to produce a lower amount of current that matches the current produced by the dye-sensitized photovoltaic cells. Alternatively or in addition, the exposure area of the dye-sensitized photovoltaic cells can be increased to match the current produced by the amorphous silicon photovoltaic cells.

In embodiments where the first and second pluralities of photovoltaic cells are disposed on the first array, the system can further include a third plurality of photovoltaic cells disposed on a second array different from the first array. In such embodiments, the first and second arrays can be electrically coupled with a charge controller device capable of combining the power output of the first and second arrays (such as that described above). The charge controller device can be electrically coupled to an external load.

The third plurality of photovoltaic cells can include dye-sensitized photovoltaic cells, amorphous silicon photovoltaic cells, monocrystalline silicon photovoltaic cells,

polycrystalline silicon photovoltaic cells, cadmium selenide photovoltaic cells, cadmium telluride photovoltaic cells, copper indium selenide photovoltaic cells, or copper indium gallium selenide photovoltaic cells. In some embodiments, the third plurality of photovoltaic cells can include cells that are the same as those in the first or second plurality of

photovoltaic cells. In some embodiments, the third plurality of photovoltaic cells can include cells that are different from those in the first or second plurality of photovoltaic cells.

In some embodiments, the system can further include a fourth plurality of

photovoltaic cells on the second array, which are electrically connected with the third plurality of photovoltaic cells. The fourth plurality of photovoltaic cells includes cells that are of different type from the cells in the third plurality of photovoltaic cells. For example, the fourth plurality of photovoltaic cells can include dye-sensitized photovoltaic cells, amorphous silicon photovoltaic cells, monocrystalline silicon photovoltaic cells,

polycrystalline silicon photovoltaic cells, cadmium selenide photovoltaic cells, cadmium telluride photovoltaic cells, copper indium selenide photovoltaic cells, or copper indium gallium selenide photovoltaic cells.

The third and fourth pluralities of photovoltaic cells can be electrically connected in series, in parallel, or in combination thereof, such as in the manner described above with respect to the first and second pluralities of photovoltaic cells.

In some embodiments, the first and second arrays described above can be placed on one substrate (e.g., to form one solar panel). In other embodiments, the first and second arrays described above can be placed on two different substrates (e.g., to form two solar panels).

In some embodiments, the system described herein can include one or more (e.g., two, three, or four) additional arrays similar to the first or second array described above.

In some embodiments, the system can be used in windows, window shades (e.g., motorized window shades), rooftop, sensors, chargers (e.g., portable chargers), or other suitable indoor or outdoor applications.

FIG. 1 is a graph showing the current output produced by a dye-sensitized

photovoltaic cell and a silicon photovoltaic cell on a cloudy day. The top curve represents the current output produced by the dye-sensitized photovoltaic ell and the bottom curve represents the current output produced by the silicon photovoltaic cell. As shown in FIG. 1, the dye-sensitized photovoltaic cell produced a significantly higher amount of current throughout the cloudy day than the silicon photovoltaic cell.

Fig. 2 is a graph showing the cumulative energy produced by the dye-sensitized photovoltaic cell and the silicon photovoltaic cell shown in FIG. 1. The top curve represents the cumulative energy produced by the dye-sensitized photovoltaic ell and the bottom curve represents the cumulative energy produced by the silicon photovoltaic cell. As shown in FIG. 2, the dye-sensitized photovoltaic cell produced a significantly higher amount of cumulative energy throughout the cloudy day than the silicon photovoltaic cell.

Fig. 3 is a graph showing the cumulative energy produced by a dye-sensitized photovoltaic cell and a silicon photovoltaic cell on a mixed day (i.e., cloudy in the morning and sunny in the afternoon). As shown in FIG. 3, the dye-sensitized photovoltaic cell produced more energy than the silicon photovoltaic cell when the light is relative low in the morning, while the silicon photovoltaic cell produced more energy than the dye-sensitized photovoltaic cell when the light is relatively strong in the afternoon.

This disclosure incorporates by reference the entire contents in commonly-owned, copending U.S. Provisional Application No. 61/845,776.

Other embodiments are in the claims.