Patent Publication Number: US-2021189795-A1

Title: Photovoltaic cells arranged in a pattern

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/629,534, filed on Feb. 24, 2015, the entire disclosure of which is incorporated by reference herein. 
    
    
     BACKGROUND 
     Fritted glass panels are well known. A fritted glass panel includes a layer of non-transparent material that is applied on a clear or a tinted glass substrate and may be arranged in a frit pattern. The non-transparent material may be a ceramic frit. A ceramic frit includes small glass particles, a pigment, and a mixing medium. The ceramic frit is applied to one side of the glass panel, which is fired in a furnace. 
     The frit pattern of a fritted glass panel may include an arrangement of dots, lines, holes, blocks, or other geometric shapes. The frit pattern may be arranged consistently across the glass panel or may vary across the glass panel. A graduated frit pattern is an example of a varied frit pattern. In a graduated frit pattern, larger shapes transition to smaller shapes gradually across the glass panel resulting in a greater amount of surface area being covered by the non-transparent material at the top of the glass panel than at the bottom of the glass panel. 
     Fritted glass panels enable the reduction of the energy consumption of electrical loads, such as lighting loads and heating, ventilation, and air-conditioning (HVAC) equipment, by diffusing sunlight and reducing solar heat gain. Fritted glass panels diffuse the sunlight while maintaining good views through the fritted glass panel. Fritted glass reduces glare from direct and/or indirect sunlight. Unlike tinted glass, fritted glass may not change the color of the sunlight entering a space. Fritted glass has various uses including commercial buildings, residential buildings, and automobiles, for example. 
     Prior art fritted glass panels do not take advantage of the sunlight energy incident on the fritted glass panel. The prior art fritted glass panels simply block a certain percentage of sunlight energy from passing through the fritted glass panel. However, being able to block and also harness the blocked sunlight energy may be desirable. 
     SUMMARY 
     As described herein, a photovoltaic film may include a plurality of photovoltaic cells arranged in a frit pattern on a transparent planar structure. The photovoltaic film may be affixed to a substrate to form a film-treated panel. The substrate may be a glass substrate, such as a windowpane. The photovoltaic cells may be configured to convert sunlight into electrical energy. The electrical energy may be stored and/or used to power an electrical device, such as a motorized window treatment, a sensor, or the like. 
     The photovoltaic film may include transparent and non-transparent portions. The non-transparent portions may be the photovoltaic cells. The photovoltaic cells may have various geometric shapes, such as dots or rectangles, for example. The geometric shapes may vary in size across the photovoltaic film to block different amounts of sunlight across the photovoltaic film. For example, the photovoltaic cells may be arranged in a frit pattern that includes a plurality of dots that vary in diameter from a first diameter at a first position on the photovoltaic film to a second diameter at a second position on the photovoltaic film. 
     The photovoltaic cells of the photovoltaic film may charge an energy storage device that may be electrically connected to the photovoltaic cells. The energy stored in the energy storage device may be used to power an electrical device, such as a motorized window treatment, a sensor, or the like. The photovoltaic cells of the photovoltaic film may produce an electrical output. The photovoltaic cells may be arranged in one or more zones. Each zone may produce an independent electrical output. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an example prior art frit pattern with dots of varying diameter. 
         FIG. 1B  is an example prior art frit pattern with rectangles of varying size. 
         FIG. 2  is a simplified cross section of a prior art photovoltaic cell. 
         FIG. 3  is a cross section of an example prior art thin-film photovoltaic cell. 
         FIG. 4A  is an example photovoltaic film having a plurality of photovoltaic cells arranged in a frit pattern. 
         FIG. 4B  is a cross section view of the example photovoltaic film shown in  FIG. 4A . 
         FIG. 5  is an illustration of an example photovoltaic film affixed to a glass substrate. 
         FIG. 6A  is an example window treatment system having a motorized window treatment for controlling an amount of daylight entering a space through a glass substrate to which a photovoltaic film is affixed. 
         FIG. 6B  and  FIG. 6C  are cross section views of an example window treatment system having a motorized window treatment for controlling an amount of daylight entering a space through a glass substrate. 
         FIG. 7  depicts an example wiring configuration for the example photovoltaic film shown in  FIG. 4A . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1A  and  FIG. 1B  illustrate example prior art frit patterns  100 ,  110  for fritted glass panels. As shown, the frit patterns may feature geometric shapes such as rectangles or dots, for example, or any combination of geometric shapes. The size of the geometric shapes may be constant throughout the frit pattern. The size of the geometric shapes may vary across the frit pattern. The example frit pattern  100  shown in  FIG. 1A  includes a plurality of dots. The dots may vary in diameter from one position on the frit pattern  100  to another position on the frit pattern  100 . For example, the frit pattern  100  may include a first dot with a first diameter at a first position and a second dot with a second diameter at a second position. The first diameter may be different than the second diameter. The example frit pattern  110  shown in  FIG. 1B  includes a plurality of rectangles. The rectangles may vary in size (e.g., width, length, or surface area) from a first position on the frit pattern  110  to a second position on the frit pattern  110 . For example, the frit pattern  110  may include a first rectangle with a first surface area at the first position and a second rectangle with a second surface area at the second position. The first surface area may be different than the second surface area. The spacing between the geometric shapes may vary across the frit pattern. For example, the spacing between the dots and/or rectangles, as respectively shown in  FIG. 1A  and  FIG. 1B , vary across the frit pattern. 
     The frit pattern may be affixed to a glass substrate, such as a glass panel or a windowpane. The spacing between the geometric shapes of the frit pattern may provide more transparent area in certain areas of the glass substrate and less transparent area in other areas of the glass substrate. The frit pattern  100 ,  110  may cover the entire glass substrate or a portion of the glass substrate. 
     Frit patterns may be arranged on windowpanes in exterior windows that separate an interior space from the environment. Frit patterns may be used in interior applications such as, privacy glass panels, space dividers, or decorative panels. The frit patterns may be customized for the intended application. 
       FIG. 2  illustrates a simplified cross section of an example prior art photovoltaic cell. A photovoltaic cell converts solar energy into electrical energy. Prior art photovoltaic cells are manufactured from a variety of materials. Referring to  FIG. 2 , an example photovoltaic cell  200  includes a cover plate  210 , an anti-reflection coating  220 , an n-type semiconductor  230 , a p-type semiconductor  240 , a front electrical contact  250 , and a back electrical contact  260 . The photovoltaic cell  200  may include a grid of front electrical contacts  250  that do not cover a large portion of the surface area of the n-type semiconductor  230 , such that the n-type semiconductor  230  may be exposed to sunlight. When exposed to sunlight, photons from the sunlight dislodge electrons in the p-type semiconductor  240 , which jump to holes in the n-type semiconductor  230 . As the dislodged electrons move from the p-type semiconductor  240  to the n-type semiconductor  230 , current flows from the front electrical contact  250  to the rear electrical contact  260 . This current may be used to charge an energy storage device (e.g., a battery or capacitor) and/or power an electrical device. 
     The n-type semiconductor  220  and p-type semiconductor  230  in traditional photovoltaic cells are silicon. Because silicon is a reflective metal, photons may reflect off of the silicon before dislodging an electron. The anti-reflection coating  210  reduces the reflectiveness of the silicon and may increase the likelihood that a photon will dislodge an electron. The cover plate  200  protects the photovoltaic cell from damage and may be positioned to be exposed to sunlight. The cover plate  200  may include glass, plastic, or a metal coated with a transparent conducting oxide. The back contact  240  creates a conductor for the flow of electrons and may be coupled to the energy storage device and/or the powered electrical device. 
       FIG. 3  depicts an example prior art thin-film photovoltaic cell  300 . The thin-film photovoltaic cell  300  may include thin semiconductor layers that can efficiently absorb sunlight energy. A thin-film photovoltaic cell semiconductor (e.g., a p-type semiconductor or an n-type semiconductor) may include amorphous silicon (a-Si), cadmium telluride (CdTe), cadmium sulfide (CdS), or copper indium gallium deselenide (CIGS). Referring to  FIG. 3 , an example thin-film photovoltaic cell  300  having a CIGS semiconductor may include a first electrical contact  310  (e.g., a zinc oxide or molybdenum electrode layer), a CdS p-type semiconductor layer  320 , a CIGS n-type semiconductor layer  330 , a second electrical contact  340  (e.g., a zinc oxide or molybdenum electrode layer), and a substrate layer  350 . When exposed to sunlight, photons from the sunlight dislodge electrons in the p-type semiconductor layer  320 , which jump to holes in the n-type semi-conductor layer  330 . As the dislodged electrons move from the p-type semiconductor layer  320  to the n-type semiconductor layer  330 , a current flows from the first electrical contact  310  to the second electrical contact  340 . This current may be used to charge an energy storage (e.g., a battery or capacitor) and/or power an electrical device. The substrate layer  350  protects the thin-film photovoltaic cell  300  from damage. The substrate layer  350  may include glass, plastic, or a metal. 
       FIG. 4A  is an example front view of a photovoltaic film  400  having a plurality of photovoltaic cells  410  arranged in a frit pattern on a transparent planar structure, such as a transparent sheet  420 . The transparent sheet  420  may be rectangular, or any suitable shape for supporting the photovoltaic cells  410  for affixing the photovoltaic film  400  to a flat surface (e.g., a window). The photovoltaic cells  410  may be thin-film photovoltaic cells, for example, as described herein, and may be non-transparent. For example, the photovoltaic cells  410  may be arranged on the transparent sheet  420  to form the frit pattern  110  depicted in  FIG. 1B . The spacing between the photovoltaic cells  410  may be constant or may vary across the photovoltaic film  400 . The photovoltaic film  400  may include non-transparent portions (e.g., one or more standard frits). 
     The photovoltaic cells  410  may be electrically coupled together via electrical connections  430  and may be connected in series or parallel. The electrical connections  430  may extend vertically between the photovoltaic cells  410  (e.g., as shown in  FIG. 4A ), may extend horizontally between the photovoltaic cells, or may form a grid pattern between the photovoltaic cells. For example, if the photovoltaic cells  410  are connected in parallel, the electrical connections  430  shown in  FIG. 4A  may each represent first and second electrical conductors, where the first electrical conductor electrically connects the positive contacts (e.g., the back electrical contacts  260  or the first electrical contacts  310 ) of two adjacent photovoltaic cells, and the second electrical conductor electrically connects the negative contacts (e.g., the front electrical contacts  250  or the second electrical contacts  340 ) of the two adjacent photovoltaic cells. The photovoltaic film  400  may produce an electrical output (e.g., to the positive and negative contacts of the photovoltaic cells  410 ). For example, if the photovoltaic cells  410  are connected in parallel, the electrical output may be provided at an uppermost electrical connection  440  as shown in  FIG. 4A . If the photovoltaic cells  410  are connected in series, the positive contact (e.g., the back electrical contact  260  or the first electrical contact  310 ) of one photovoltaic cell may be electrically connected to the negative contact (e.g., the front electrical contact  250  or the second electrical contact  340 ) of an adjacent photovoltaic cell. For example, the photovoltaic cells  410  of a column (e.g., as shown in  FIG. 4A ) may be electrically connected in series, and the columns of series-connected photovoltaic cells may be electrically connected in parallel. 
       FIG. 4B  is a cross section view of the example photovoltaic film shown in  FIG. 4A . The thin-film photovoltaic cells  410  of the photovoltaic film  400  may be arranged to form the frit pattern. The thin-film photovoltaic cells  410  may convert sunlight energy into electrical energy. Each thin-film photovoltaic cell  410  includes multiple layers, and may include a first electrical contact  410  (e.g., a first electrode layer), a p-type semiconductor  420 , an n-type semiconductor  430 , a second electrical contact  440  (e.g., a second electrode layer), and a substrate layer  450 . When exposed to sunlight, photons from the sunlight dislodge electrons in the p-type semiconductor layer  420 , which jump to holes in the n-type semi-conductor layer  430 . As the dislodged electrons move from the p-type semiconductor layer  420  to the n-type semiconductor layer  430 , a current flows from the first electrical contact  410  to the second electrical contact  440 . This current may be used to charge an energy storage (e.g., a battery or capacitor) and/or power an electrical device. The substrate layer  450  protects the thin-film photovoltaic cells  410  from damage. The substrate layer may include glass, plastic, or a metal. 
       FIG. 5  depicts an example film-treated panel  500  having a photovoltaic film  510  affixed to a transparent substrate  520 . The transparent substrate  520  may be a glass panel, such as a windowpane. The photovoltaic film  510  may be affixed to the transparent substrate  520  to form a film-treated panel. The photovoltaic film  510  may be an example of the photovoltaic film  400  shown in  FIG. 4A  and  FIG. 4B . The photovoltaic film  510  may include one or more thin-film photovoltaic cells arranged in a frit pattern. The photovoltaic film  510  may be affixed to the entire transparent substrate  520  or to only a portion of the transparent substrate  520 . The photovoltaic film  510  may be affixed to the transparent substrate  520  using an adhesive agent, which may include double sided tape, polydimethylsiloxane (PDMS), or the like. 
       FIG. 6A  is an example window treatment system having a motorized window treatment  610  for controlling an amount of daylight entering a space through a glass substrate, e.g., a windowpane  650 . A photovoltaic film  600  (e.g., the photovoltaic film  400  and/or the photovoltaic film  510 ) may be affixed to the windowpane  650 . The photovoltaic film  600  may be a smaller size than the windowpane  650  and may be affixed to only a portion of the windowpane  650 . The photovoltaic film  600  may cover the entire windowpane  650 . For example, the photovoltaic film  600  may be affixed to a top portion of the windowpane  650 , as shown in  FIG. 6A . 
     As described herein, the photovoltaic cells of the photovoltaic film  600  may produce an electrical output, which may be used to power a control device, such as the motorized window treatment  610 , a remote control device, a lighting control device, a panaboard, or a sensor  620 , for example. The sensor  620  may be a daylight sensor, an occupancy sensor, a shadow sensor, or the like. The electrical output of the photovoltaic film  600  may be used to power a controlled device, such as a motorized window treatment  610 , for example. The motorized window treatment  610  may include motorized shades, motorized blinds, or the like. The electrical output of the photovoltaic film  600  may be electrically connected to an energy storage device (e.g., a battery or a capacitor). The energy storage device may store electrical energy harnessed by the photovoltaic cells in the photovoltaic film  600 . The energy storage device may be electrically connected to one or more devices. The stored electrical energy may power the one or more devices. 
     The motorized window treatment  610  may be controlled by one or more control devices, such as, a wall-mounted remote control device  640  or a tabletop remote control device  630 . The wall-mounted remote control device  640  or the tabletop remote control device  630  may transmit one or more control signals (e.g., wireless signals) to the motorized window treatment  610 . The motorized window treatment  610  may use power from the electrical output of the photovoltaic film  600  or the energy storage device to operate in response to the control signals. 
     The photovoltaic film  600  may be further configured to detect, sense, and/or measure environmental characteristics. For example, the photovoltaic film  600  may be configured to detect, sense, and/or measure a daylight intensity, an occupancy condition, a shadow, a glare condition, or the like. The control device may use the harnessed information regarding the environmental characteristics to control devices such as the motorized window treatment  610 , for example. 
     The photovoltaic film  600  may be configured as a daylight sensor. The photovoltaic film  600  may measure the amount of daylight entering a space. The motorized window treatment  610  may be controlled to achieve a desired light intensity in the space based on the measured daylight. For example, the motorized window treatment  610  may be adjusted such that the covering material is raised when the measured daylight decreases. As another example, the motorized window treatment may be adjusted such that the covering material is lowered when the measured daylight increases. 
     The photovoltaic film  600  may be configured as a shadow sensor. The electrical output of the photovoltaic film  600  may indicate the presence of a shadow on the windowpane  650 . For example, the control device may determine the presence of a shadow on the windowpane  650  by sensing a change in voltage on an electrical output of the photovoltaic film  600 . As the surface area of the windowpane  650  covered by a shadow increases, the electrical output produced by the photovoltaic cells in the photovoltaic film  600  may decrease, for example, decrease proportionally. The motorized window treatment  610  may be controlled based on the presence of a shadow (e.g., to improve the view out of the window). The photovoltaic film  600  may detect a glare (e.g., a source of intense glare). The detected glare may be caused, for example, by the sun shining off of an adjacent building. The motorized window treatment  610  may be controlled based on the detected glare. For example, the covering material of the window treatment  610  may be lowered to limit the glare (e.g., limit the effect of the glare on occupants of the space). Examples of controlling motorized window treatments in response to shadow sensors are described in greater detail in commonly-assigned U.S. Patent Application No. 2014/0262057, published Sep. 18, 2014, entitled METHOD OF CONTROLLING A WINDOW TREATMENT USING A LIGHT SENSOR, the entire disclosure of which is hereby incorporated by reference. 
     The photovoltaic film  600  may have an occupancy sensing circuit (e.g., an occupancy sensor) embedded in the film. The occupancy sensing circuit may generate a control signal when motion is detected in the space. The control signal may be provided to a control device such as the motorized window treatment  610  or a lighting control device, for example. Examples of occupancy sensors are described in greater detail in commonly-assigned U.S. Pat. No. 8,009,042, issued Aug. 30, 2011 Sep. 3, 2008, entitled RADIO-FREQUENCY LIGHTING CONTROL SYSTEM WITH OCCUPANCY SENSING, and U.S. Pat. No. 8,228,184, issued Jul. 24, 2012, entitled BATTERY-POWERED OCCUPANCY SENSOR, the entire disclosures of which are hereby incorporated by reference. 
       FIG. 6B  and  FIG. 6C  are cross section views of an example window treatment system having a motorized window treatment  625  for controlling an amount of daylight entering a space through a glass substrate, e.g., a windowpane  605 . A photovoltaic film  615  (e.g., the photovoltaic film  400 , the photovoltaic film  510 , and/or the photovoltaic film  600 ) may be affixed to the windowpane  605 . The photovoltaic film  615  may be a smaller size than the windowpane  605  and may be affixed to a portion of the windowpane  605 . For example, the photovoltaic film  615  may be affixed to a top portion of the windowpane  605 . The photovoltaic film  615  may prevent more sunlight from entering the room from the top of the windowpane  605  than at the bottom of the windowpane  605 . 
     Sunlight may pass through the windowpane  605  and may be incident on the photovoltaic film  615 . As shown, a portion of the sunlight passes through the photovoltaic film  615  and may be incident on the motorized window treatment  625 . The motorized window treatment  625  may be partially extended. When partially or fully extended, the motorized window treatment  625  may block or filter sunlight from the portion of the windowpane  605  and photovoltaic film  615  that is incident on the motorized window treatment  625 . When the motorized window treatment  625  is partially extended, sunlight may enter the room below the motorized window treatment  625 , as shown. 
     A control device may sense that sunlight is entering the room or that sunlight is incident on the entire windowpane  605 . As shown in  FIG. 6C , the motorized window treatment  625  may be operated to extend to a fully extended position that prevents any sunlight, which passes through the windowpane  605  and the photovoltaic film  615 , from entering the room. As shown in  FIG. 6B , the motorized window treatment  625  may be operated to retract to a partially extended position or a fully retracted position, for example when sunlight is not incident on the windowpane  605  or full view through the windowpane  605  is desired. The motorized window treatment  625  may receive a signal to operate or may operate automatically. 
       FIG. 7  illustrates an example wiring configuration for the example photovoltaic film. The photovoltaic film  700  may include a plurality of photovoltaic cells  710 . The plurality of photovoltaic cells  710  may be thin-film photovoltaic cells, for example. The electrical output of the photovoltaic film may be a combined output that includes the current produced by each of the plurality of photovoltaic cells  710 . The photovoltaic film  700  may include two or more electrical outputs. The two or more electrical outputs could be based on two or more zones of photovoltaic cells  710 . Each of the plurality of photovoltaic cells  710  may be wired to a common hot  720  and a common ground  730 . The plurality of photovoltaic cells  710  may be wired in parallel. The plurality of photovoltaic cells  710  may be wired from a front electrical contact of a first photovoltaic cell to a rear electrical contact of a second photovoltaic cell, which is adjacent to the first photovoltaic cell. A front electrical contact of the second photovoltaic cell may be wired to a rear electrical contact of a third photovoltaic cell, which is adjacent to the second photovoltaic cell.