Elongated photovoltaic cells in tubular casings

Abstract

A solar cell unit comprising a cylindrical shaped solar cell and a transparent tubular casing is provided. The tubular shaped solar cell comprises a back-electrode, a semiconductor junction circumferentially disposed on the back-electrode and a transparent conductive layer disposed on the semiconductor junction. The transparent tubular casing is circumferentially sealed onto the transparent conductive layer of the cylindrical shaped solar cell. A solar cell unit comprising a cylindrical shaped solar cell, a filler layer, and a transparent tubular casing is provided. The cylindrical shaped solar cell comprises a cylindrical substrate, a back-electrode circumferentially disposed on the cylindrical substrate, a semiconductor junction circumferentially disposed on the back-electrode, and a transparent conductive layer disposed on the semiconductor junction. The filler layer is circumferentially disposed on the transparent conductive layer and the transparent tubular casing is circumferentially disposed onto the filler layer.

1 . A solar cell unit comprising: 
 (A) a cylindrical shaped solar cell, said cylindrical shaped solar cell comprising: 
 a rigid substrate that is either (i) tubular or (ii) a solid rod;  
 a back-electrode circumferentially disposed on the substrate;  
 a semiconductor junction layer circumferentially disposed on said back-electrode; and  
 a transparent conductive layer circumferentially disposed on said semiconductor junction; and  
   (B) a transparent tubular casing circumferentially disposed onto said cylindrical shaped solar cell.    
     
     
         2 . The solar cell unit of  claim 1 , wherein the transparent tubular casing is made of plastic or glass.  
     
     
         3 . The solar cell unit of  claim 1 , wherein the transparent tubular casing comprises aluminosilicate glass, borosilicate glass, dichroic glass, germanium/semiconductor glass, glass ceramic, silicate/fused silica glass, soda lime glass, quartz glass, chalcogenide/sulphide glass, fluoride glass, flint glass, or cereated glass.  
     
     
         4 . The solar cell unit of  claim 1 , wherein the transparent tubular casing comprises a urethane polymer, an acrylic polymer, a fluoropolymer, a silicone, a silicone gel, an epoxy, a polyamide, or a polyolefin.  
     
     
         5 . The solar cell unit of  claim 1 , wherein the transparent tubular casing comprises polymethylmethacrylate (PMMA), poly-dimethyl siloxane (PDMS), ethylene vinyl acetate (EVA), perfluoroalkoxy fluorocarbon (PFA), nylon, cross-linked polyethylene (PEX), polypropylene (PP), polyethylene terephtalate glycol (PETG), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), or polyvinylidene fluoride (PVDF).  
     
     
         6 . The solar cell unit of  claim 1 , wherein the rigid substrate comprises plastic or glass.  
     
     
         7 . The solar cell unit of  claim 1 , wherein the rigid substrate comprises metal or metal alloy.  
     
     
         8 . The solar cell unit of  claim 1 , wherein the rigid substrate comprises a urethane polymer, an acrylic polymer, a fluoropolymer, polybenzamidazole, polymide, polytetrafluoroethylene, polyetheretherketone, polyamide-imide, a glass-based phenolic, polystyrene, cross-linked polystyrene, polyester, polycarbonate, polyethylene, acrylonitrile-butadiene-styrene, polytetrafluoro-ethylene, polymethacrylate, nylon 6,6, cellulose acetate butyrate, cellulose acetate, rigid vinyl, plasticized vinyl, or polypropylene.  
     
     
         9 . The solar cell unit of  claim 1 , wherein the rigid substrate comprises aluminosilicate glass, borosilicate glass, dichroic glass, germanium/semiconductor glass, glass ceramic, silicate/fused silica glass, soda lime glass, quartz glass, chalcogenide/sulphide glass, fluoride glass, a glass-based phenolic, flint glass, or cereated glass.  
     
     
         10 . The solar cell unit of  claim 1 , wherein the rigid substrate is tubular shaped and a fluid is passed through said substrate.  
     
     
         11 . The solar cell unit of  claim 10 , wherein the fluid is air, water, nitrogen, or helium.  
     
     
         12 . The solar cell unit of  claim 1 , wherein the rigid substrate has a solid core.  
     
     
         13 . The solar cell unit of  claim 1 , wherein the back-electrode is made of aluminum, molybdenum, tungsten, vanadium, rhodium, niobium, chromium, tantalum, titanium, steel, nickel, platinum, silver, gold, an alloy thereof, or any combination thereof.  
     
     
         14 . The solar cell unit of  claim 1 , wherein the back-electrode is made of indium tin oxide, titanium nitride, tin oxide, fluorine doped tin oxide, doped zinc oxide, aluminum doped zinc oxide, gallium doped zinc oxide, boron doped zinc oxide, indium-zinc oxide, a metal-carbon black-filled oxide, a graphite-carbon black-filled oxide, a carbon black-filled oxide, a superconductive carbon black-filled oxide, an epoxy, a conductive glass, or a conductive plastic.  
     
     
         15 . The solar cell unit of  claim 1 , wherein the semiconductor junction comprises a homojunction, a heterojunction, a heteroface junction, a buried homojunction, a p-i-n junction, or a tandem junction.  
     
     
         16 . The solar cell unit of  claim 1 , wherein the transparent conductive layer comprises carbon nanotubes, tin oxide, fluorine doped tin oxide, indium-tin oxide (ITO), doped zinc oxide, aluminum doped zinc oxide, gallium doped zinc oxide, boron doped zinc oxides indium-zinc oxide or any combination thereof.  
     
     
         17 . The solar cell unit of  claim 1 , wherein said semiconductor junction comprises an absorber layer and a junction partner layer, wherein said junction partner layer is circumferentially disposed on said absorber layer.  
     
     
         18 . The solar cell unit of  claim 17 , wherein said absorber layer is copper-indium-gallium-diselenide and said junction partner layer is In 2 Se 3 , In 2 S 3 , ZnS, ZnSe, CdInS, CdZnS, ZnIn 2 Se 4 , Zn 1-x Mg x O, CdS, SnO 2 , ZnO, ZrO 2 , or doped ZnO.  
     
     
         19 . The solar cell unit of  claim 17 , wherein said absorber layer is between 0.5 μm and 2.0 μm thick.  
     
     
         20 . The solar cell unit of  claim 17 , wherein a composition ratio of Cu/(In+Ga) in said absorber layer is between 0.7 and 0.95.  
     
     
         21 . The solar cell unit of  claim 17 , wherein a composition ratio of Ga/(In+Ga) in said absorber layer is between 0.2 and 0.4.  
     
     
         22 . The solar cell unit of  claim 17 , wherein the absorber layer comprises CIGS having a <110> crystallographic orientation.  
     
     
         23 . The solar cell unit of  claim 17 , wherein the absorber layer comprises CIGS having a <112> crystallographic orientation.  
     
     
         24 . The solar cell unit of  claim 17 , wherein the absorber layer comprises CIGS that is randomly oriented.  
     
     
         25 . The solar cell unit of  claim 1 , wherein the cylindrical shaped solar cell further comprises an intrinsic layer circumferentially disposed on said semiconductor junction and wherein the transparent conductive layer is disposed on said intrinsic layer.  
     
     
         26 . The solar cell unit of  claim 25 , wherein the intrinsic layer comprises an undoped transparent oxide.  
     
     
         27 . The solar cell unit of  claim 25 , wherein the intrinsic layer comprises undoped zinc oxide.  
     
     
         28 . The solar cell unit of  claim 1 , further comprising a filler layer circumferentially disposed on said transparent conductive layer, wherein said transparent tubular casing is circumferentially disposed on said filler layer thereby circumferentially sealing said cylindrical shaped solar cell.  
     
     
         29 . The solar cell unit of  claim 28 , wherein the filler layer comprises ethylene vinyl acetate (EVA), silicone, silicone gel, epoxy, polydimethyl siloxane (PDMS), RTV silicone rubber, polyvinyl butyral (PVB), thermoplastic polyurethane (TPU), a polycarbonate, an acrylic, a fluoropolymer, or a urethane.  
     
     
         30 . The solar cell unit of  claim 1 , further comprising a water resistant layer circumferentially disposed on said transparent conductive layer, wherein said transparent tubular casing is circumferentially disposed on said water resistant layer thereby circumferentially sealing said cylindrical shaped solar cell.  
     
     
         31 . The solar cell unit of  claim 30 , wherein the water resistant layer comprises clear silicone, SiN, SiO x N y , SiO x , or Al 2 O 3 , where x and y are integers.  
     
     
         32 . The solar cell unit of  claim 1 , further comprising: 
 a water resistant layer circumferentially disposed on said transparent conductive layer; and    a filler layer circumferentially disposed on said water resistant layer, wherein said transparent tubular casing is circumferentially disposed on said filler layer thereby circumferentially sealing said cylindrical shaped solar cell.    
     
     
         33 . The solar cell unit of  claim 1 , further comprising: 
 a filler layer circumferentially disposed on said transparent conductive layer; and    a water resistant layer circumferentially disposed on said water resistant layer, wherein said transparent tubular casing is circumferentially disposed on said water resistant layer thereby circumferentially sealing said cylindrical shaped solar cell.    
     
     
         34 . The solar cell unit of  claim 1 , further comprising an antireflective coating circumferentially disposed on said transparent tubular casing.  
     
     
         35 . The solar cell unit of  claim 34 , wherein the antireflective coating comprises MgF 2 , silicon nitrate, titanium nitrate, silicon monoxide, or silicon oxide nitrite.  
     
     
         36 . The solar cell unit of  claim 1 , wherein said cylindrical shaped solar cell has a cylindrical axis, said cylindrical shaped solar cell further comprising at least one electrode strip, wherein each electrode strip in the at least one electrode strip is overlayed on the transparent conductive layer along the cylindrical axis of the solar cell.  
     
     
         37 . The solar cell unit of  claim 36 , wherein the at least one electrode strip comprises a plurality of electrode strips that are positioned at spaced intervals on the transparent conductive layer such that the plurality of electrode strips run parallel or approximately parallel to each other along the cylindrical axis of the solar cell.  
     
     
         38 . The solar cell unit of  claim 37 , wherein electrode strips in the plurality of electrode strips are spaced out at sixty degree intervals on a surface of the transparent conductive layer.  
     
     
         39 . The solar cell unit of  claim 37 , wherein electrode strips in the plurality of electrode strips are spaced out at even intervals on a surface of the transparent conductive layer.  
     
     
         40 . The solar cell unit of  claim 37 , wherein electrode strips in the plurality of electrode strips are spaced out at uneven intervals on a surface of the transparent conductive layer.  
     
     
         41 . The solar cell unit of  claim 36 , wherein the at least one electrode strip comprises a conductive epoxy, a conductive ink, copper or an alloy thereof, aluminum or an alloy thereof, nickel or an alloy thereof, silver or an alloy thereof, gold or an alloy thereof, a conductive glue, or a conductive plastic.  
     
     
         42 . The solar cell unit of  claim 36 , wherein the at least one electrode strip comprises a plurality of electrode strips overlayed on the transparent conductive layer along the cylindrical axis of the solar cell; and wherein said cylindrical shaped solar cell further comprises at least one grid line that electrically connects a first electrode strip and a second electrode strip in the plurality of electrode strips.  
     
     
         43 . The solar cell unit of  claim 1 , wherein a length of said cylindrical shaped solar cell is between 2 centimeters and 300 centimeters.  
     
     
         44 . The solar cell unit of  claim 1 , wherein a length of said cylindrical shaped solar cell is between 2 centimeters and 30 centimeters.  
     
     
         45 . The solar cell unit of  claim 1 , wherein a length of said cylindrical shaped solar cell is between 30 centimeters and 300 centimeters.  
     
     
         46 . A solar cell assembly comprising a plurality of solar cell units, each solar cell unit in the plurality of solar cell units having the structure of the solar cell unit of  claim 1 , wherein solar cell units in said plurality of solar cell units are arranged in coplanar rows to form said solar cell assembly.  
     
     
         47 . The solar cell assembly of  claim 46 , further comprising an albedo surface positioned to reflect sunlight into the plurality of solar cell units.  
     
     
         48 . The solar cell assembly of  claim 47 , wherein the albedo surface has an albedo that exceeds 80%.  
     
     
         49 . The solar cell assembly of  claim 47 , wherein the albedo surface is Lambertian or diffuse.  
     
     
         50 . The solar cell assembly of  claim 46 , wherein a first solar cell unit and a second solar cell unit in the plurality of solar cell units is electrically arranged in series.  
     
     
         51 . The solar cell assembly of  claim 46 , wherein a first solar cell unit and a second solar cell unit in the plurality of solar cell units is electrically arranged in parallel.  
     
     
         52 . The solar cell unit of  claim 1 , wherein an outer surface of the transparent tubular casing is textured.  
     
     
         53 . A solar cell assembly comprising: 
 a plurality of solar cell units, each solar cell unit in the plurality of solar cell units having the structure of the solar cell unit of  claim 1;  and    a plurality of internal reflectors, wherein    the plurality of solar cell units and the plurality of internal reflectors are arranged in coplanar rows in which internal reflectors in the plurality of solar cell units abut solar cell units in the plurality of solar cell units thereby forming the solar cell assembly.    
     
     
         54 . The solar cell assembly of  claim 53 , wherein an internal reflector in said plurality of internal reflectors has a hollow core.  
     
     
         55 . The solar cell assembly of  claim 53 , wherein an internal reflector in said plurality of internal reflectors comprises a plastic casing with a layer of reflective material deposited on said plastic casing.  
     
     
         56 . The solar cell assembly of  claim 55 , wherein the layer of reflective material is polished aluminum, aluminum alloy, silver, nickel or steel.  
     
     
         57 . The solar cell assembly of  claim 53 , wherein an internal reflector in said plurality of internal reflectors is a single piece made out of a reflective material.  
     
     
         58 . The solar cell assembly of  claim 57 , wherein the reflective material is polished aluminum, aluminum alloy, silver, nickel or steel.  
     
     
         59 . The solar cell assembly of  claim 53 , wherein an internal reflector in said plurality of internal reflectors comprises a plastic casing onto which is layered a metal foil tape.  
     
     
         60 . The solar cell assembly of  claim 59 , wherein the metal foil tape is aluminum foil tape.  
     
     
         61 . The solar cell assembly of  claim 53 , wherein a cross-sectional shape of an internal reflector in said plurality of internal reflectors is asteroid or involute.  
     
     
         62 . The solar cell assembly of  claim 53 , wherein 
 a cross-sectional shape of an internal reflector in said plurality of internal reflectors is four-sided; and    a side of said four-sided cross-sectional shape is linear, parabolic, concave, circular or elliptical.    
     
     
         63 . The solar cell assembly of  claim 53 , wherein 
 a cross-sectional shape of an internal reflector in said plurality of internal reflectors is four-sided; and    a side of said four-sided cross-sectional shape defines a diffuse surface on said internal reflector.    
     
     
         64 . The solar cell assembly of  claim 53 , wherein a first solar cell unit and a second solar cell unit in the plurality of solar cell units is electrically arranged in series.  
     
     
         65 . The solar cell assembly of  claim 53 , wherein a first solar cell unit and a second solar cell unit in the plurality of solar cell units is electrically arranged in parallel.  
     
     
         66 . A solar cell unit comprising: 
 (A) a solar cell comprising: 
 a substrate, wherein the substrate is either (i) tubular shaped or (ii) rigid solid shaped;  
 a back-electrode circumferentially disposed on said substrate;  
 a semiconductor junction circumferentially disposed on said back-electrode; and  
 a transparent conductive layer disposed on said semiconductor junction;  
   (B) a filler layer circumferentially disposed on said transparent conductive layer; and    C) a transparent tubular casing circumferentially disposed onto said filler layer.    
     
     
         67 . The solar cell unit of  claim 66 , wherein said substrate has a solid core.  
     
     
         68 . The solar cell unit of  claim 66 , wherein the substrate comprises plastic, metal or glass.  
     
     
         69 . The solar cell unit of  claim 66 , wherein the substrate comprises a urethane polymer, an acrylic polymer, a fluoropolymer, polybenzamidazole, polymide, polytetrafluoroethylene, polyetheretherketone, polyamide-imide, glass-based phenolic, polystyrene, cross-linked polystyrene, polyester, polycarbonate, polyethylene, polyethylene, acrylonitrile-butadiene-styrene, polytetrafluoro-ethylene, polymethacrylate, nylon 6,6, cellulose acetate butyrate, cellulose acetate, rigid vinyl, plasticized vinyl, or polypropylene.  
     
     
         70 . The solar cell unit of  claim 66 , wherein the substrate comprises aluminosilicate glass, borosilicate glass, dichroic glass, germanium/semiconductor glass, glass ceramic, silicate/fused silica glass, soda lime glass, quartz glass, chalcogenide/sulphide glass, fluoride glass, a glass-based phenolic, flint glass, or cereated glass.  
     
     
         71 . The solar cell unit of  claim 66 , wherein said semiconductor junction comprises an absorber layer and a junction partner layer, wherein 
 said junction partner layer is circumferentially disposed on said absorber layer; and    said absorber layer is circumferentially disposed on said back-electrode.    
     
     
         72 . The solar cell unit of  claim 71 , wherein said absorber layer is copper-indium-gallium-diselenide and said junction partner layer is CdS, SnO 2 , ZnO, ZrO 2 , or doped ZnO.  
     
     
         73 . The solar cell unit of  claim 71 , wherein the absorber layer comprises CIGS having a <110> crystallographic orientation. a <112> crystallographic orientation, or no crystallographic orientation.  
     
     
         74 . The solar cell unit of  claim 66 , wherein said solar cell unit further comprises: 
 (D) an antireflective coating circumferentially disposed on said transparent tubular casing.    
     
     
         75 . The solar cell unit of  claim 74 , wherein the antireflective coating comprises MgF 2 , silicone nitrate, titanium nitrate, silicon monoxide, or silicone oxide nitrite.  
     
     
         76 . The solar cell unit of  claim 66 , wherein  
       
         
           
             
               
                 r 
                 i 
               
               ≥ 
               
                 
                   r 
                   o 
                 
                 
                   η 
                   
                     outer 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     ring 
                   
                 
               
             
           
         
       
       wherein 
 r i  is a radius of the cylindrical shaped solar cell;  
 r o  is the radius of the transparent tubular casing; and  
 η outer ring  is the refractive index of the transparent tubular casing.  
 
     
     
         77 . The solar cell unit of  claim 66 , wherein the transparent tubular casing is formed directly on said filler layer by casting or UV curing.  
     
     
         78 . The solar cell unit of  claim 66 , wherein the transparent tubular casing comprises a plurality of transparent tubular casing layers including a first transparent tubular casing layer and a second transparent tubular casing layer, and wherein the first transparent tubular casing layer is circumferentially disposed on said filler layer and the second transparent tubular casing layer is circumferentially disposed on said first transparent tubular casing layer.  
     
     
         79 . A solar cell unit comprising: 
 (A) a solar cell comprising: 
 a substrate, wherein said substrate is either (i) tubular shaped or (ii) rigid solid rod shaped;  
 a back-electrode circumferentially disposed on the substrate;  
 a semiconductor junction circumferentially disposed on the back-electrode; and  
 a transparent conductive layer disposed on the semiconductor junction;  
   (B) a water resistant layer circumferentially disposed on the transparent conductive layer;    (C) a filler layer circumferentially disposed on the water resistant layer; and    (D) a transparent tubular casing circumferentially disposed on the filler layer.    
     
     
         80 . The solar cell unit of  claim 79 , wherein said substrate is a tube.  
     
     
         81 . The solar cell unit of  claim 79 , wherein  
       
         
           
             
               
                 r 
                 i 
               
               ≥ 
               
                 
                   r 
                   o 
                 
                 
                   η 
                   
                     outer 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     ring 
                   
                 
               
             
           
         
       
       wherein 
 r i  is a radius of the cylindrical shaped solar cell;  
 r o  is the radius of the transparent tubular casing; and  
 η outer ring  is the refractive index of the transparent tubular casing.  
 
     
     
         82 . The solar cell unit of  claim 79 , wherein the transparent tubular casing comprises a plurality of transparent tubular casing layers including a first transparent tubular casing layer and a second transparent tubular casing layer, and wherein the first transparent tubular casing layer is circumferentially disposed on said filler layer and the second transparent tubular casing layer is circumferentially disposed on said first transparent tubular casing layer.  
     
     
         83 . The solar cell unit of  claim 79 , wherein the transparent tubular casing is formed by casting or UV curing directly onto the filler layer.  
     
     
         84 . A solar cell unit comprising: 
 (A) a solar cell comprising: 
 a substrate, wherein said substrate is tubular shaped or rigid solid rod shaped;  
 a back-electrode circumferentially disposed on said substrate;  
 a semiconductor junction circumferentially disposed on said back-electrode; and  
 a transparent conductive layer disposed on said semiconductor junction;  
   (B) a filler layer circumferentially disposed on said transparent conductive layer; and    (C) a water resistant layer circumferentially disposed on said filler layer; and    (D) a transparent tubular casing circumferentially disposed onto said water resistant layer.    
     
     
         85 . The solar cell unit of  claim 84 , wherein  
       
         
           
             
               
                 r 
                 i 
               
               ≥ 
               
                 
                   r 
                   o 
                 
                 
                   η 
                   
                     outer 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     ring 
                   
                 
               
             
           
         
       
       wherein 
 r i  is a radius of the cylindrical shaped solar cell;  
 r o  is the radius of the transparent tubular casing; and  
 η outer ring  is the refractive index of the transparent tubular casing.  
 
     
     
         86 . The solar cell unit of  claim 84 , wherein said substrate is a tube.  
     
     
         87 . The solar cell unit of  claim 84 , wherein the transparent tubular casing is formed by casting or UV curing directly onto the water resistant layer.  
     
     
         88 . The solar cell unit of  claim 1 , wherein  
       
         
           
             
               
                 r 
                 i 
               
               ≥ 
               
                 
                   r 
                   o 
                 
                 
                   η 
                   
                     outer 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     ring 
                   
                 
               
             
           
         
       
       wherein 
 r i  is a radius of the cylindrical shaped solar cell;  
 r o  is the radius of the transparent tubular casing; and  
 η outer ring  is the refractive index of the transparent tubular casing.  
 
     
     
         89 . The solar cell unit of  claim 1 , wherein the transparent tubular casing is formed directly on said cylindrical shaped solar cell by casting or UV curing.  
     
     
         90 . The solar cell unit of  claim 1 , wherein the transparent tubular casing comprises a plurality of transparent tubular casing layers including a first transparent tubular casing layer and a second transparent tubular casing layer, and wherein the first transparent tubular casing layer is circumferentially disposed on said semiconductor junction and the second transparent tubular casing layer is circumferentially disposed on said first transparent tubular casing layer.  
     
     
         91 . The solar cell unit of  claim 1 , wherein the transparent conductive layer is coated with a fluorescent material.  
     
     
         92 . The solar cell unit of  claim 1 , wherein a luminal or an exterior surface of said transparent tubular casing is coated with a fluorescent material.  
     
     
         93 . The solar cell unit of  claim 32 , wherein the water resistant layer or the filler layer is coated with a fluorescent material.  
     
     
         94 . The solar cell unit of  claim 33 , wherein the filler layer or the water resistant layer is coated with a fluorescent material.  
     
     
         95 . The solar cell unit of  claim 1 , wherein the rigid substrate is a plastic rod.  
     
     
         96 . The solar cell unit of  claim 1 , wherein the rigid substrate is a glass rod.  
     
     
         97 . The solar cell unit of  claim 1 , wherein the rigid substrate is a glass tube.  
     
     
         98 . The solar cell unit of  claim 1 , wherein the substrate is a plastic tube.