Patent Publication Number: US-2012031488-A1

Title: Photovoltaic cell module assembly

Description:
This application claims priority to U.S. Provisional Patent Application Ser. No. 61/371,485, incorporated herein in its entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to mountings for photovoltaic elements. 
     BACKGROUND OF THE INVENTION 
     There are many places on the Earth that cover significant amounts of surface area, but lack any appreciable need for complete open-air exposure. As an example, open air parking lots, or the uppermost level of parking garage buildings, are both exposed areas where people may only be for a short time, before heading into whichever building(s) the parking lots or garages service, and thus would not generally desire complete sunlight exposure. In the context of parking lots, reduced sunlight exposure may indeed be beneficial to reduce the increase in interior car temperature as a vehicle sits in direct sunlight. Other places, such as the rooftops of some buildings (in particular commercial buildings), may seldom or never be visited, or even seen, by those wishing to have direct views of the sky. In yet other places, such as the ponds of water/sewage treatment plants, it may be desirable to reduce external visibility of such surfaces for aesthetic purposes, or to make better use of an otherwise open space. 
     Any such open-air surface area is exposed to massive amounts of solar radiation, and represents a significant opportunity for solar energy generation. Environmental, economical, or other considerations may make the installation of photovoltaic cells at such areas desirable. The possibility of capturing solar energy radiating on such exposed areas creates the possibility of offsetting operating expenses for property owners (for example by reducing dependence on electricity provided by utility companies), or even may be profit generating (if sufficient electricity is produced such that an excess may be sold). Moreover, irrespective of the potential financial benefits, the ability to take advantage of this open-air space to generate electricity by solar cell technology is entirely environmentally positive. Specifically, the electricity generated will have no carbon emissions, and takes advantage of open-air space that already exists, thus avoiding intrusion into undeveloped areas, which is often the case with large solar cell farms. 
     Numerous mounting styles exist for solar cell technologies to capture solar energy radiating onto open-air spaces. Because large-scale photovoltaic cells are typically substantial in both size and weight, mountings for such cells may be equally impressive. In many cases, such as when cells are installed onto the rooftops of buildings, the mountings may be close to the rooftop, or may be laid on the rooftop surface itself. One potential issue with such mountings are, of course, the loss of access to structure beneath the photovoltaic cells, which on most commercial buildings may include HVAC compressors or other mechanical accoutrements. In the above examples, where the open space is typically used for parking, some mounting that suspends the photovoltaic cells above the vehicles increases efficient space usage (see, e.g., U.S. patent application Ser. No. 12/537038, the entirety of which is incorporated by reference). 
     In some conventional photovoltaic mounting systems, large flat canopy structures are used to support a large array of rigid wide format solar panels. While this may effectively provide the solar energy generating functionality, such structures are poorly suited for use in an exposed outdoor environment. Specifically, such large flat canopy structures can create a significant amount of lift or downward force under high wind conditions. As such, the support structure and associated connections must be overdesigned to ensure sufficient stability and strength to withstand such forces. Also, in Northern regions, snow or ice may gather on these structures, significantly adding to their weight (these roof structures are also typically oriented at a specific angle to the sun creating limitations and concentrating water run-off to one end of the structure where it needs to be captured and diverted). This results in a structure that is significantly more expensive, and may also be aesthetically unsightly. 
     Accordingly, the present inventor has recognized a long-felt but unresolved need for an improved photovoltaic cell mounting structure that functions to effectively capture solar radiation for conversion to electricity, yet has a structural design is lighter, and which may be elevated across a long span. 
     SUMMARY OF THE INVENTION 
     One aspect of the invention provides a photovoltaic module having an elongated base member with first and second extensions shaped to define an elongated support plane along ends thereof. The elongated support plane extends in a direction of elongation for the elongated base member. The photovoltaic module further comprises at least one photovoltaic cell assembly positioned at the ends of the elongated base member, extending generally along the elongated support plane. The elongated base member and the at least one photovoltaic cell assembly define a volume of space therein. 
     Another aspect of the invention provides a photovoltaic module comprising an elongated base member having a partially tubular configuration with a longitudinally extending opening. The modules further comprises an elongated photovoltaic cell assembly comprising a rigid backing member mounted to the base member to cover the longitudinally extending opening and form a tubular member with the base member. The photovoltaic cell assembly further comprises a plurality of photovoltaic elements mounted to an outer surface of the backing member, and a transparent protective layer coated over the photovoltaic elements. The photovoltaic module further comprises at least one terminal coupled to the photovoltaic elements for conducting of electricity generated by the photovoltaic elements. 
     Another aspect of the invention provides a photovoltaic cell system comprising a plurality of cables extending across a span. The system further includes a pair of support structures arranged in spaced apart relation from one another and configured to elevate and secure the plurality of cables above the span. The system additionally includes a plurality of elongated photovoltaic modules, each connected to and extending across at least two of said plurality of cables. The system further provides for one or more photovoltaic elements, each supported by one or more of said plurality of elongated photovoltaic modules 
     Other objects, features, and advantages of the present invention will become apparent from the following detailed description, the appended claims, and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view of a photovoltaic cell system comprising a plurality of cables extending over and above a span, so as to provide a space beneath a plurality of photovoltaic cells installed thereon (only a few photovoltaic modules are included, so the full extent of the support system can be seen); 
         FIG. 2  is a closer perspective view of the photovoltaic system of  FIG. 1 , taken from a lower angle to highlight a support structure configured to elevate the cables above the span; 
         FIGS. 3A and 3B  are a top elevation views of the photovoltaic system of  FIG. 1 , illustrating non-limiting embodiments of arrangements of elongated photovoltaic modules for the plurality of photovoltaic cells; 
         FIG. 4  is a closer perspective view of the photovoltaic system of  FIG. 1  than that of  FIG. 2 , illustrating angling of the photovoltaic modules on the plurality of cables; 
         FIG. 5  is a side profile view of the photovoltaic system of  FIG. 1 , showing angling of the photovoltaic modules and anchoring of the cable; 
         FIGS. 6A and 6B  are bottom perspective views of the elongated photovoltaic modules of  FIG. 1 , illustrating non-limiting embodiments of mounting supports for the modules; 
         FIG. 7  is a side view of one of the elongated photovoltaic modules of  FIG. 1 , illustrating the mounting thereof to the cable, and electrical connections for the photovoltaic cells thereof; 
         FIG. 8  is a side cutaway view of another embodiment of one of the photovoltaic modules, showing an alternative mounting support therefore, and a light therein; 
         FIG. 9  is a side cutaway view of another embodiment of one of the photovoltaic modules, showing a construction configured to form a groove to support a light element therein; and 
         FIG. 10  is a top perspective view of an embodiment of one of the photovoltaic modules, showing the photovoltaic cells thereon. 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT(S) OF THE INVENTION 
     The present application discloses photovoltaic cell system  10  with integrated solar cell photovoltaic technology. The illustrated embodiment is not intended to be limiting, and system  10  may have other configurations, constructions, and materials other than those mentioned below. 
     As shown in  FIG. 1 , system  10  provides a mechanism for arranging and supporting photovoltaic cell modules  20 , described in greater detail below. Although system  10  may be utilized in any appropriate environment, system  10  may be particularly useful in arranging and supporting cell modules  20  across span S. Although the illustrated embodiment in  FIG. 1  is assembled over the reservoirs of a water or sewage treatment plant, span S may include areas such as parking lots, building rooftops, fields, industrial facilities, roads, driveways, railroad tracks, canals, rivers, or so on. Any area that is outdoors and exposed to radiation from the sun, may be a suitable location for installation of system  10 . 
     The basic components of system  10  are cell modules  20 , a plurality of cables  30 , and a pair of support structures  40 . As  FIG. 1  illustrates, the pair of support structures  40  lift cables  30  over span S, providing a space underneath. Although some cell modules  20  are shown in the figure, many are omitted for clarity of the Figure. In many embodiments cell modules  20  may be arranged throughout the entire length of cables  30 , as is discussed in greater detail below. The length of span S may be of any appropriate length, but may be limited by the strength of cables  30  and cell modules  20 . In an embodiment, cell modules  20  may be optimized to reduce their weight, so as to permit the installation of more cell modules  20  onto cables  30  across span S. In some non-limiting embodiments, the length of span S (across which cables  30  extend), may be between 15 and 200 feet long. In some embodiments, wherein span S is sufficiently long, additional support structures  40  may be placed at appropriate intervals to reduce strain on cables  30 . 
     The space provided beneath cables  30  may be of any height, and may be customizable based on the environment in which system  10  is installed. For example, in the illustrated embodiment, wherein span S comprises water for a treatment plant, the spacing between the cables and the surface below may be only a small amount sufficient to keep cell modules  20  away from the foul water. In other installations, the spacing may be larger, so that a boat or barge may be placed in the water, in case access is needed for maintenance purposes. In installations wherein span S is a parking lot or other area where people may regularly be driving or walking, the spacing between cables  30  and the surface below may vary. Preferably in such installations, cables  30  should be spaced a sufficient amount to enable conventional motor vehicles (cars, pick-up trucks, etc.) to park beneath it without obstruction, and for people to walk to and from their vehicles comfortably. For example, cables  30  may be spaced at least 7 feet above the ground surface, and preferably 7.5 feet, 8 feet or 8.5 feet. Other heights may be used. 
     Cables  30  may be of any suitable construction or configuration. In various non-limiting embodiments, cables  30  may comprise wire, cord, rope, or chain. For example, cables  30  may be a solid elongated structure, may be braided or twisted, or may be formed from a plurality of links. Cables  30  may be constructed from any suitable material, including but not limited to metal, fiber, or synthetic materials. Cables  30  may essentially be formed from any suitable material capable of supporting cell modules  20  above span S. 
     Turning to  FIG. 2 , the configuration of an embodiment of support structures  40  may be appreciated. The illustrated support structures are not intended to be limiting, and in some embodiments the support structures for cables  30  may be pre-existing structures, such as the roofs of adjacent buildings, adjacent high voltage towers, adjacent radio masts, or any other spaced structure. As shown in the illustrated embodiment, however, support structures  40  may be assembled specifically to raise cables  30  to a spaced height above span S. As shown, each of support structures  40  may comprise a pair of columns  50  connected at an upper end by cross beam  60 . Each of columns  50  are shown as substantially comprising a single girder, having an I-beam configuration. In other embodiments, columns  50  may be comprised of multiple elements, and the illustrated construction is not intended to be limiting. Cables  30  may be mounted to or pass over cross beam  60 , which is also shown as substantially comprising a single girder, but in other embodiments may comprise multiple elements. In an embodiment, the height that columns  50  lift cross beam  60  may define the general height of cables  30  above span S. As described above, this may be any suitable height, including but not limited to approximately 7-8 feet, such that a person may comfortably traverse the underside of cables  30  across span S. 
     As shown in the illustrated embodiment, cross beam  60  may have cable guides  70  mounted thereon, which may receive the lengths of cables  30  from across span S, and may redirect cables  30  so that they may be secured or anchored. In some embodiments, cable guides  70  may apply a force to cables  30 , and may be used to tighten cables  30  to prevent sagging. In some embodiments, system  10  may further provide a cable tightener to adjust a tension on one or more of the plurality of cables  30 . In an embodiment the cable tightener may be located at support structure  40 . In some embodiments, the cable tightener may anchor cables  30 , and may, for example, comprise a winch configured to receive an end of at least one cable  30 . 
     Columns  50  may be mounted into footing  80 , which may comprise concrete or other dense material to provide a sturdy and secure foundation for support structures  40 . In an embodiment, footing  80  may include one or more anchors extending into the Earth to provide a more stable foundation, and prevent movement of support structures  40  with respect to span S. Examples of an anchor may include, but are not limited to, drives piles, caissons, helical piles/screws, etc. To prevent tipping or other failure of columns  50 , support structures  40  may further include one or more braces  90  to support columns  50 . Braces  90  may also be mounted into footing  80 , and in an embodiment may extend at an angle to intersect columns  50 , distributing the forces (such as tension forces) resulting from the pull of cables  30  on cross beam  60 . As shown in the illustrated embodiment, second cross beam  100  may extend between braces  90 , on which cables  30  may be anchored. 
     As seen in the Figure, in an embodiment, a plurality of support structures  40  may be provided wherein each are associated with a subset of the plurality of cables  30 . As shown, each support structure  40  may support four of cables  30 . In other embodiments, each support structure  40  may support less cables  30  (i.e. two cables  30 ) or more cables  30  (i.e. if the separate support structures  40  of  FIG. 2  were connected). As shown, in some embodiments, support structures  40  may share a common footing  80 . 
     Support structures  40  may be of any suitable construction or configuration, including but not limited to metals such as iron, steel, or aluminum, natural formations such as rocks, trees, or soil, or building materials such as brick, concrete, or processed wood. As stated above, any structure that is capable of supporting cables  30 , raising them to the desired spaced height above span S, and preventing them from failing under the weight of cell modules  20  may be utilized to support or anchor cables  30 . 
     For example, the vertical columns/support for vertically supporting cables  30  and the cable end anchor(s) to which cables  30  are connected to maintain tension in cables  30  may be provided as separate structures, rather than sharing a common footing  80  as illustrated. In such an approach, cable  30  and anchors would typically use a secure ground anchor or anchors (examples provided above) to resist the pulling/tension of cables  30 . 
     Illustrated in  FIGS. 3A and 3B  are non-limiting examples of how cell modules  20  may be arranged on or mounted to cables  30 , the mechanics of which are described in greater detail below. Seen in  FIG. 3A  is a top view of the arrangement of cell modules  20  seen in  FIGS. 1 and 2 . As shown, each cell module  20  is associated with and supported by two of cables  30 . As shown, associated pairs of cables  30  may form columns of cell modules  20 , hereinafter referred to as strings  110 . In some non-limiting embodiments, each string  110  of cell modules  20  may be electrically connected to one another. The spacing of cables  30  from one another may be determined by the size of cell modules  20 . In some embodiments, cell modules  30  may be substantial in length, but not in width. For example, in some exemplary embodiments, each cell module  20  may be approximately 18 feet long, but only approximately one foot wide. In some embodiments, cell modules may be associated with more than two cables  30 , to provide additional support for cell modules  20 . 
     In some embodiments, cell modules  20  along and between strings  110  may be spaced from one another. In some embodiments, the spacing is achieved by the mounting of cell modules  20  on cables  30 . In other embodiments, the spacing may be achieved by spacers placed between cell modules  20  to help separate them, which may reduce overall weight at any point on cable  30 , or may allow some sunlight through between cell modules  20 . Such a spaced apart relation also permits airflow between cell modules  20 . That is, because cell modules  20  are spaced apart from one another, wind blowing over cell modules  20  can flow through the spaces therebetween. This minimizes any lift or downward force generated by airflow over the plurality of cell modules  20 , as may occur with sheets of photovoltaic cells forming a solid canopy structure. Likewise, snow or water will fall through the open spaces, thus eliminating or minimizing the accumulation of snow and ice (or other precipitation, such as hail) in cold conditions. The spacing between cell modules  20  may be of any size, and in an embodiment, may be at least four inches, so as to minimize the potential for snow buildup, or to optimize airflow between cell modules  20 . 
     Although the spaced apart relation of cell modules  20  may minimize lift or downward forces on cell modules  20 , in some embodiments strings  110  of cell modules  20  may still be prone to twisting or be subject to other unwanted forces. In some embodiments, such twisting may be further minimized by providing lateral cross braces connecting the pluralities of cables  30  at one or more spaced intervals, such that all strings  110  of cell modules  20  are interconnected at one or more places. The lateral cross braces may additionally provide lift for the pluralities of cables  30 , and may be positioned to reduce sagging of cables  30  under the weight of cell modules  20 . Such lateral cross braces may comprise additional cables that extend across the plurality of cables  30 . In some embodiments, the lateral cross braces may be anchored to additional support structures  40  oriented perpendicular to support structures  40  for cables  30 . In other embodiments, the lateral cross braces may be anchored only to cables  30  themselves, which may serve to more evenly distribute the weight of cell modules  20 . In some embodiments, the lateral cross braces may be interwoven alternatively above or below adjacent cables  30 . 
       FIG. 3B  shows an alternative arrangement for cell modules  20 , which may reduce or eliminate twisting or the need for lateral cross braces by providing greater interconnection across cables  30 . As shown, instead of forming strings  110 , cell modules  20  may be staggered across adjacent cables  30 , creating a stretcher-bond bricklayer-like appearance for cell modules  20 , as shown. Such a staggered configuration may more evenly distribute the weight of cell modules  20  without the need for a dedicated lateral cross brace. In some embodiments, cell modules  20  may generally be arranged in strings  110 ; however, they may also intermittently be arranged in staggered association with adjacent cables  30 , thus indirectly associating a larger number of adjacent cables  30  with one another. 
     As is shown in  FIGS. 4 and 5 , in some embodiments, each of cell modules  20  may be angled with respect to the direction of cables  30  along span S. Although the connection between cables  30  and cell modules  20  are described in greater detail below, it may be appreciated that depending on the location of system  10 , the sun may rise at a different portion of the sky, and for parts of the year may track across an acute angle formed with the horizon. An ideal angle for cell modules  20  to receive light from the sun may change according to the time of year, the location of the system, precision of the Earth, or so on. For these or other reasons, angling of cell modules  20  may permit a greater amount of light to fall on the photovoltaics of cell modules  20 , allowing the generation of greater amounts of electricity. In some embodiments, cell modules  20  may contain mechanical tracking devices configured to allow the angle of cell module  20  as against cables  30  to change as the sun moves across the sky, to further optimize light collection by cell module  20 . 
     As is illustrated in greater detail in  FIG. 5 , in some embodiments, the angles that cell modules  20  form with respect to cables  30  may be optimized such that the most common path of the sun across the sky creates shadows predominantly in the spacing between cell modules  20  on cables  30 , and not on the photovoltaics of cell modules  20 . Such an optimization may comprise adjusting the shape of cell modules  20 , the spacing of cell modules  20  on cables  30 , or so on. In some embodiments, the angles that cell modules  20  are mounted at with respect to cables  30  may vary, such that different cell modules  20  are optimized to receive light from the sun from different times during the day. In some embodiments, sagging of cables  30  may be accounted for in the angles at which cell modules  20  are mounted. 
     In  FIGS. 6A and 6B , non-limiting embodiments of the mounting of cell modules  20  to cables  30  may be appreciated. These embodiments are exemplary, and may vary across different embodiments of system  10 , such as differing depending on the configuration of cable  30 . Shown in  FIG. 6A  is the underside of an embodiment of cell module  20 . As shown, cell module  20  includes base member  120 . In the illustrated embodiment, base member  120  may be a convex arcuate surface. In some embodiments, the mounting for cables  30  may be built directly into base member  120 . For example, base member  120  may include a plurality of associated perforations along the arcuate shape, configured to receive cable  30  through any two of the perforations. In the illustrated embodiment of  FIGS. 6A , however, mounting bracket  130  attached to base member  120  is provided, which may be attached to cables  30  in a variety of ways. As shown, bracket  130  comprises two apertures  140  formed as elongated slots therein, through which may be installed cable engaging member  150 . Fasteners  160  on cable engaging member  150  may allow cable engaging member  150  to be tightened onto different areas of apertures  140 , allowing greater adjustability of the angle formed between cable  30  and mounting bracket  130  (and thus, cell module  20 ). Many cable engaging members  150  are known in the art, such as but not limited to U-shaped bolt  170 , seen installed on bracket  130  in  FIG. 6A . In other embodiments, other generally U-shaped brackets may also be installed around cable  30  to secure cable  30  to bracket  130  or base member  120 , and may be fastened by other means such as welding, adhesive, screws, or so on. Another non-limiting example of cable engaging member  150  may include the assembly of two bolts  180  with one or more cross-members  190 , shown alongside U-shaped bolt  170 , which may clamp onto cable  30 , and secure it to either another cross member  180  or to bracket  130  or base member  120 . 
     Where cables  30  lack apertures therein, any body that may create an enclosure to secure cables  30  to brackets  130  and/or base members  120  may be utilized. Other examples of such cable engaging members  150  may include cable ties (i.e. zip ties), twist ties (i.e. bent wire), straps, or so on. In some embodiments, cable engaging members  150  may comprise knotted thread, twine, or rope. In some embodiments, cable engaging members  150  may be threaded through apertures  140 , creating a loop through which cables  30  may be fed so that cables  30  are generally perpendicular to a direction of elongation for cell modules  20 . 
     In an alternative embodiment shown in  FIG. 6B , bracket  130  of cell modules  20  may comprise a single aperture  140 , through which may be threaded a single bolt  180 . Such a bolt  180  may be acceptable to mount cell modules  20  to cables  30  where, for example, cables  30  comprise apertures therein. For example, where cables  30  are chains, bolt  180  may be passed through an aperture of a link in the chain of cable  30 , and secured by fasteners  160 . Again, the mechanism for mounting cell module  20  to cables  30  may vary depending on the constituent makeup of cables  30 . In some embodiments, an appropriate adhesive may be utilized to bond cables  30  to cell module  20 . For example, where cables  30  are comprised of metal, in some embodiments cell modules  20  may be welded directly to cables  30 . In such embodiments, a generally curved shape of base member  120  or bracket  130  may allow the varying position of the welding to adjust the angle that the photovoltaics of cell module  20  forms with cables  30 . In other embodiments, such as where cables  30  comprise a fabric material such as rope, a cable engaging member may be utilized such as pins, needles, spikes, or other similar bodies that may push through a portion of cables  30  to secure cell modules  20  onto cables  30 . Other constructions or configurations may be used, and the listed examples are not intended to be limiting. 
     Turning to  FIG. 7 , a side view of an embodiment of cell module  20  is depicted as mounted to cable  30 . As shown, bracket  130  is mounted to base member  120  of cell module  20 , spaced so that a portion of cable engaging member  150  may be secured by fasteners  160 . In some embodiments, once cable engaging member  150  is installed onto a selected position of bracket  130 , their combination may then be installed onto base member  120  of cell module  20 . Also seen from the side view depicted is photovoltaic cell assembly  200 , containing the active photovoltaics of cell module  20 , installed onto base member  120 . The composition of photovoltaic cell assembly  200  is described in greater detail below. In the illustrated embodiment, base member  120  comprises a generally arcuate body defined by first and second extensions  210   a  and  210   b  outwardly extending from a common point (i.e. a midpoint), whereby photovoltaic cell assembly  200  is retained or otherwise supported by the endpoints of base member  120  at the ends of first and second extensions  210   a - b . It may be appreciated that the ends of the first and second extensions  210   a  and  210   b  of the elongated base member  120  may generally define an elongated support plane that extends therebetween. When photovoltaic cell assembly  200  is retained or otherwise supported by the ends, photovoltaic cell assembly  200  may generally extend along the elongated support plane. It may be appreciated that “extending generally along the elongated support plane,” implies that at least a portion of photovoltaic cell assembly  200  resides along the plane, and is elongated with the elongated support plane. To be clear, in various embodiments portions of photovoltaic cell assembly  200  may be outside the elongated support plane, or may be angled with respect to the elongated support plane. 
     It may be appreciated that while in some embodiments first extension  210   a  may be integrally coupled to or formed with second extension  210   b,  in other embodiments, first and second extensions  210   a - b  may be formed separately and subsequently coupled or otherwise assembled together, as described in greater detail below. It may be also be appreciated that the shape of first and second extensions  210   a - b  as they extend from the common point towards photovoltaic cell assembly  200  defines space  215  between base member  120  and photovoltaic cell assembly  200 . It may be appreciated that space  215  may define a volume between base member  120  and photovoltaic cell assembly  200 . Space  215  may therefore be a region generally bounded by base member  120  and photovoltaic cell assembly  200 , and may in some embodiments be sufficiently voluminous so as to facilitate containing elements of cell module  20  therein, as described in greater detail below. In some embodiments, space  215  may be bounded by the elongated support plane, while in other embodiments photovoltaic cell assembly  200  may be shaped so as to meet the ends of base member  120 , such that a portion of the elongated support plane extends within space  215 . Although in some embodiments space  215  may be generally or completely enclosed, in other embodiments, gaps between elements of photovoltaic cell assembly  200  and/or base member  120  (i.e. between first and second extensions  210   a - b ), and/or apertures within photovoltaic cell assembly  200  and/or elements of base member  120  (i.e. in first or second extensions  210   a - b ), may provide external access to space  215 . 
     As shown in the illustrated embodiment, first and second extensions  210   a - b  may comprise or be connected to associated inwardly extending lips  220   a - b , which may prevent outward removal of photovoltaic cell assembly  200 . In an embodiment, photovoltaic cell assembly  200  may be further supported from the interior of base member  120  such that photovoltaic cell assembly  200  does not slip away from lips  220   a - b . In some embodiments, lips  220   a - b  and another portion associated with base member  120  may form slots extending in the direction of elongation for cell modules  20 , so that one or more photovoltaic cell assemblies  200  may slide into to install photovoltaic cell assemblies  200  into base member  120 . In other embodiments, photovoltaic cell assemblies  200  may be mounted to the ends of first and second extensions  210   a - b , instead of being retained within them. For example, lips  220   a - b  may form a ledge to support photovoltaic cell assemblies  200 . In some embodiments the mounting of photovoltaic cell assemblies  200  to base member  120  may be with screws, bolts, adhesive, or any other appropriate fastener. In an embodiment, multiple mechanisms to fasten photovoltaic cell assemblies  200  into base member  120  may be utilized. 
     Photovoltaic cell assemblies  200  may be of any suitable construction configured to support active photovoltaics for cell modules  20 . In an embodiment, photovoltaic cell assembly  200  may comprise a rigid backing member or substrate, which may be of any suitable construction, including but not limited to plastic or foam. In various embodiments, the backing member may comprise polycarbonate, fiberglass, glass, polycarbonate, and/or aluminum laminate (two thin layers of aluminum laminated together using a plastic waffle-like structure). In some embodiments, the backing member may be in a honeycomb or other porous configuration to reduce the weight of cell modules  20 . In some embodiments, the backing member may comprise or be surrounded by layers or a rigid material, such as in the aforementioned aluminum laminate, or any other sturdy material, to increase the structural stability of photovoltaic cell assembly  200 , while maintaining a relatively light weight. The active photovoltaics of cell assembly  200  may reside against the backing member or the rigid material facing away from base member  120 , to receive light shining onto the active photovoltaics for conversion into electricity. In an embodiment, cell assembly  200  may comprise transparent protective material  225  placed over the active photovoltaics on the side facing away from base member  120 , so as to prevent damage to the active photovoltaics. In some embodiments, the backing member may be a thicker transparent protective material  225 , and the active photovoltaics may be mounted to the underside of transparent protective material  225 , to increase protection from the exterior environment. While in some embodiments lips  220  may also be configured to retain both photovoltaic cell assembly  200  and transparent protective material  225 , in other embodiments, such as that shown, transparent protective material  225  may be adhered directly to photovoltaic cell assembly  200 . The active photovoltaics and transparent protective material  225  are discussed in greater detail below. 
     In an embodiment, photovoltaic cell assemblies  200  may be bonded using any suitable adhesive, including but not limited to EVA or other clear plastic sheets in a vacuum lamination process. In an embodiment, if the adhesive is between the light collecting portion of the active photovoltaics and a transparent body such as transparent protective material  225 , the adhesive is preferably light transmissive, so as to enable the maximum amount of light transmittance to occur onto photovoltaic cell assembly  200 . In an embodiment, a backing of photovoltaic cell assembly  200  may be larger than the active photovoltaics so that bonding may be at the edge of the backing, thus avoiding any adhesive between the active photovoltaics and the interior surface of base member  120 . 
     Further shown in the side view of  FIG. 7  are electrical terminals  230  for the one or more photovoltaic cell assemblies  200  of cell module  20 . The manner in which photovoltaic cell assemblies  200  function, by receiving solar radiation and converting the solar radiation to electricity, is known and need not be detailed herein. In an embodiment, both positive and negative terminals  230  may be provided on the same side of elongation for cell module  20 , which may simplify the connection of electrical cables to electrically connect cell modules  20  associated with the same cables  30  on the same string  110 . In some embodiments, the positive and negative terminals  230  may be positioned on opposing sides of elongation for cell module  20 , which may simplify the connection of electrical cables to electrically connect cell modules  20  of the same row on different strings  110 . In some embodiments, cables  30  may be electrically conductive, such as where they are formed from metal, and thus may serve to electrically connect cell modules  20  of string  110  in parallel. For example, where two cables  30  are associated with string  110 , one cable  30  may be associated with the positive terminal  230  for each cell module  20 , while the second cable  30  may be associated with the negative terminal  230  for each cell module  20 . In such embodiments, the electrical connection between the respective terminals  230  and the electrically conductive cables  30  may be formed through cable engaging member  150 . The manner of establishing electrical connections may vary. For example, instead of wiring, integrated connectors may be built into the various components to facilitate such connections during assembly. Thus, the application is not limited to the examples mentioned herein. 
     Other electrical connections between cell modules  20  are also possible. Connecting all cell modules  20  in series maximizes the potential or voltage, while connecting cell modules  20  in parallel maximizes current output. In some embodiments, it may be desirable to combine both parallel and serial connected cell modules  20  to provide desired levels of both voltage and current. Various combinations of serial and parallel connected cell modules  20  may be used, and this description is not intended to be limiting. 
     In many embodiments, a power output may be established for string  110  of cell modules  20 , or for all cell modules  20  in system  10 , to output the electricity converted in each of cell modules  20 . In various embodiments, the power output may be located on or near one or more of structural supports  40 . This power output may be any suitable device for collecting the electricity and distributing the same to a larger network or grid. For example, the power output may be an inverter, which is a standard piece of equipment used to convert the DC electrical signal generated by photovoltaic elements in cell modules  20  into an AC signal that is compatible for use with standard power grids. As another alternative, the power output could simply output a DC signal, whereby a common inverter may receive DC signals from a plurality of systems  10 , and convert them to an AC signal. 
     The power output may couple to one or more energy storage devices, such as a rechargeable battery, so that the energy generated may be stored for later use. This is particularly beneficial because the photovoltaic power generation does not function at night, and may be interrupted for long or short periods during the day. The use of an energy storage device allows for continued output of electricity, even when demand for the electricity does not coincide with the power generation of the photovoltaic cells. The electricity generated by the photovoltaic cells may be used by adjacent buildings or other devices, as is discussed in greater detail below, or may be sold to the local power grid to generate revenue. 
     Each component of cell modules  20  supporting photovoltaic cell assembly  200  may be formed of any suitable material, including but not limited to aluminum, stainless steel, composite materials, plastics, polymers, other metals, or so on. Further to reducing the weight of cell modules  20 , and the forces that are placed on cables  30 , lightweight materials are preferable. In an embodiment, base member  120  may be constructed from polycarbonate, PVC, fiberglass, and/or acrylic. In an embodiment, base member  120  may be formed from a half round tube having a flat top surface for mounting photovoltaic cell assemblies  200 . In the illustrated embodiment of a half-round tube configuration for base member  120 , the diameter of the tube may be selected to match the width of photovoltaic cell assembly  200 ; however other widths may be selected. As shown in  FIG. 8 , which depicts another embodiment of cell module  20 , the half round tube may be made in a continuous casting process, and/or may have a profile departing from a simple half circle. As an example, the shape can be generally elliptical, or polygonal. To be clear, in some embodiments, base member  120  may generally conform to other tube shapes, including but not limited to a generally half circular shape, a generally half elliptical shape, or so on. Likewise, in some embodiments, the shape of the tube configuration of base member  120  might be polygonal, as opposed to rounded, in configuration. For example, as described above, base member  120  might form a triangular prism shape when combined with photovoltaic cell assembly  200 , or may contain additional facets, such that the tube configuration of base member  120  forms a rectangular, pentagonal, hexagonal, or other multi-faceted polygonal shape when combined with photovoltaic cell assemblies  200 . Additionally, in some embodiments, base member  120  may contain both rounded and polygonal portions. The walls of base member  120  may be of any suitable thickness, and in an embodiment base member  120  may contain structural embellishments  240 , as shown, which may strengthen base member  120 . 
     In the embodiment of  FIG. 8 , structural embellishments  240  of base member  120  may be configured to amplify light emitted by one or more light sources  250 , and thus may act as a plurality of lenses. In such an embodiment, the material of base member  120  may be at least partially transparent, such as if, for example, base member  120  comprises optical grade polycarbonate. In an embodiment, a series of light sources  250  may be placed along the length of cell module  120 , so as to illuminate the area below base member  120 . In various embodiments, light sources  250  may be attached to the underside of photovoltaic cell assembly  200 , or may be attached to base member  120 . In an embodiment, light sources  250  may comprise light emitting diodes (LEDs), which may be soldered directly to a printed circuit board  260  extending along the length of cell module  20 , and may be at least partially powered directly or indirectly (i.e. through a storage battery) by photovoltaic cell assemblies  200 . In other embodiments, light sources  250  may comprise other types of lighting, including but not limited to incandescent, florescent, or metal halide. The use of light sources  250  in cell modules  20  may be useful when system  10  is installed in an area prone to travel, or where lighting is needed, such as if system  10  is installed over a parking lot. In some embodiments, the backing of photovoltaic cell assembly  200  may have an adherent quality, which may allow adhesion of light source  250 , printable circuit board  260  and/or other elements of cell module  20 . 
     As noted above, in some embodiments, first and second extensions  210   a - b  may be formed as separate bodies, which may be subsequently joined together to form base member  120 . An example of such an embodiment is shown in  FIG. 9 , where first extension  210   a  and second extension  210   b  meet together at a common meeting point. In the illustrated embodiment, clip  270  secures the meeting edges of first and second extensions  210   a - b  together. In other embodiments, any other securing mechanism may be utilized, including but not limited to fasteners, adhesives, crimping, folding onto one another, or so on. As shown in the illustrated embodiment of  FIG. 9 , in some embodiments, first and second extensions  210   a - b  may be shaped to form channel  280  around their common meeting point, along the outside of base member  120 . In various embodiments, light source  250  may be positioned in channel  280 , such that light source  250  is supported by base element  120 . In an embodiment, light source  250  may comprise one or more light elements that extend along channel  280  (i.e. as a strip of lights, or as an elongated light tube). In an embodiment, cover  290  may at least partially enclose channel  280 , and in some embodiments may generally follow a contour shape defined by base member  120 . In an embodiment containing light source  250  in channel  280 , cover  290  may be transparent such that light source  250  may emit light therethrough. 
     As further shown in  FIG. 9 , in some embodiments, first and second extensions  210   a - b  may be configured to support printed circuit board  260  within space  215 . Additionally, in various embodiments, other components may be mounted inside base member  120  (i.e. in space  215 ), such as on printed circuit board  260 , to the interior of first and second extensions  210   a - b , or to the backing of photovoltaic cell assembly  200 . For example, in various embodiments sensors, power conversion devices, or other electronics may be installed, which may also be at least partially powered directly or indirectly (i.e. through a storage battery) by photovoltaic cell assemblies  200 . As shown in the illustrated embodiment, power inverter  300  is installed in space  215 , which may be electrically coupled to light sources  250 . It may be appreciated that in embodiments where light sources  250  are LEDs, light sources  250  would utilize DC power. Accordingly, power inverter  300  may facilitate converting AC power (i.e. from the grid) to DC power to power light sources  250  or other electronic systems at cell module  20  once photovoltaic cell assembly  200  is no longer producing DC power. In some embodiments where batteries or other power storage is located in space  215  or otherwise are associated with cell module  20 , power inverter  300  might be utilized solely for conversion of the DC power generated by photovoltaic cell assembly  200  to AC power for supplying the electrical grid. Depending on light sources  250  used in such embodiments of cell module  20 , or other electrical systems utilized in cell module  20 , various components such as but not limited to resistors, capacitors, and integrated circuits may be mounted to printed circuit board  260  to supply appropriate power to light sources  250  or those other electrical systems. In some embodiments, printed circuit board  260  may carry the electrical current generated by photovoltaic cell assemblies  200 , and may direct the current to terminals  230 . In some embodiments, wires and other electronic connections associated with cell module  20  (i e running to and from printed circuit board  260 ) may be housed within space  215 . 
     In some embodiments, base member  120  may further house additional elements (i.e. at least partially in space  215 , or otherwise coupled to base member  120 ), such as but not limited to motion detectors, cameras, displays, or RFID tag readers. In an embodiment, such as when base member  120  includes a motion detector comprising a passive infrared detector, cell module  120  may detect when a person or vehicle is near system  10 , and may perform some response function, such as turning on light sources  250 , displaying content on the displays, recording video on the cameras, or so on. For example, content displayed on the displays may serve as an electronic billboard. In such an embodiment, some of base members  120  in system  10  could be fitted with a long character or graphic displays to provide information or advertising. For example, where system  10  is installed over a parking lot, the graphic displays and motion detectors could be used to track empty parking spaces, and indicate to drivers where a free space is available for the driver to park. In embodiments containing cameras, the cameras may be used to provide security, or identify vehicles parked under cell modules  20 . In embodiments comprising an RFID tag reader, the reader may be used to read a tag mounted on cars parked below cell modules  20 , and may transmit this information to enable billing (such as parking fees, for example). 
     In an embodiment, circuitry can be added to system  10  to monitor the health of cell modules  20 , such as by measuring electric output and solar input (i.e. by using a photo detector). In an embodiment, the circuitry may include a temperature sensor to help calibrate power measurements, and warn of environmental conditions, such as the threat of icing. 
     In some embodiments, information about cell modules  20 , such as from the sensors, may be transmitted to a central data collection point. In some embodiments, this transmission may be wireless, including but not limited to via cellular, 802.11 WiFi, Zigbee®, or Bluetooth® transmission standards. In some embodiments, the transmission may be through wires, such as through dedicated data cables, or through power cables connecting cell modules  20  (i.e. through transmission standards such as HomePlug®, X10, or other power line communications). In an embodiment, information collected from cell modules  20  may be utilized to track the utilization of parking spaces, alert authorities to the presence of intruders, or so on. In an embodiment, cell modules  20  may contain controllers that may be controlled via the wired or wireless transmission standards described above, for example. Such controllers may receive external commands, which may perform a variety of functions, including controlling light sources  250 , the displays, the cameras, or so on. 
     As noted above, in some embodiments, it may be desirable to convert the direct current (DC) output of photovoltaic cell assemblies  200  into alternating current (AC) compatible with utility grids. Such conversion is typically performed by an inverter such as power inverter  300 , which in some embodiments may be mounted onto or at least partially inside base member  120  (i.e. extending into space  215 ). In an embodiment, power inverter  300  may be a separate assembly inside base member  120 , or may be assembled into printed circuit board  260 . In embodiments where power inverter  300  is incorporated into cell modules  20 , light sources  250  may be controlled by the same wire used for AC output of cell module  20 . Likewise, light sources  250  may be controlled by the same networked controller as is used for power inverter  300 , which may reduce circuitry required in each cell module  20 , by having the same processor handle control functions for both the inverter and light sources  250 . The same controller may additionally be used to control the sensors or other electronic components located in cell module  20 . In some embodiments, other energy sensing or harnessing technologies may additionally be used in cell modules  20 , such as wind impellers for further electricity generation. 
     Turning now to  FIG. 10 , an embodiment of cell module  20  is seen from an elevated perspective view, such that active photovoltaics  310  on photovoltaic cell assemblies  200  are shown. It may be appreciated that in various embodiments cell module  20  is greatly elongated. For example, in some embodiments cell module  20  has a general ratio of height to length that is approximately greater than 1:3, including for example, approximately 1:5, approximately 1:7, approximately 1:10, approximately 1:15, or so on. As seen, the illustrated embodiment of cell module  20  comprises numerous active photovoltaics  310  arranged in an array. In some embodiments, active photovoltaics  310  may be associated with different photovoltaic cell assemblies  200 , which may in combination be assembled onto base member  120 . In the illustrated embodiment, base member  120  has associated therewith two photovoltaic cell assemblies  200 , each having a strip of active photovoltaics  310  thereon, such that cell module  20  contains an array of active photovoltaics  310  that is two active photovoltaics  310  wide, and significantly longer in active photovoltaics  310  in length. The number of active photovoltaics  310  on each photovoltaic cell assembly  200  and in each cell module  20  may vary, and the size of base member  120  and/or the size of photovoltaic cell assemblies  200  may increase to compensate. As described above, photovoltaic cell assemblies  200  and transparent protective material  225  may be of any construction or configuration. In some embodiments, however, transparent protective material  225  on the outer external surface of photovoltaic cell assembly  200  may be of a non-glass configuration, such as that disclosed in U.S. Patent Application Publication No. 2009/0272436, incorporated herein by reference. Although conventional glasses may be used as the transparent protective materials  225  in some embodiments, it may be appreciated that a non-glass configuration may reduce the weight of cell modules  20 , allowing more cell modules  20  to be arranged on cables  30 . In an embodiment, photovoltaic cell assemblies  200  may comprise crystalline silicon or thin film cells mounted to the backing member between first and second extensions  210   a - b.    
     In an embodiment, transparent protective material  225  may be a top layer of laminate over photovoltaic cell assembly  200 . In an embodiment, transparent protective material  225  can be a coating material such as DuPontTM Tefzel® or other fluoropolymer, which may provide a suitable vapor barrier and provide weathering resistance. This material may be coated directly onto photovoltaic cell assemblies  200 , and cured in place over active photovoltaics  310  and backing member. This not only weighs less than glass and may be thinner than glass, but may also avoid the need for an adhesive layer between it and active photovoltaics  310 , which may detract from light transmission. In some embodiments, the backing member may be comprised of multiple bodies that are joined together, either through adhesion, fasteners, interlocking, or any other mechanism. In an embodiment, photovoltaic cell assemblies  200  may comprise thin films arranged on the backing member attached to base member  120 . The film used may be a CIGS film, which refers to the materials providing the film with its photovoltaic characteristic: copper-indium-gallium-diselenide. Such films are known in the solar cell industry, and are available from, for example, Global Solar Energy, Inc., 8500 South Rita Road, Tucson, Ariz., 85747, USA. 
     The foregoing embodiments have been provided solely to illustrate the structural and functional principles of the present invention and are not intended to be limiting. To the contrary, the present invention is intended to encompass all modifications, substitutions, alterations, and equivalents within the spirit and scope of the following claims.