Abstract:
A photovoltaic module mounting cartridge has a frame structure for mounting a plurality of photovoltaic modules thereon, the frame structure having supports for engaging with and supporting an associated mounting rail provided on the underside of a photovoltaic module such that the photovoltaic module can be selectively installed or removed from the cartridge. A method of assembling a photovoltaic module mounting cartridge is also described, comprising providing a frame structure, providing a plurality of photovoltaic modules having at least one associated mounting rail, arranging the photovoltaic modules atop the frame structure, and attaching each associated mounting rail to the frame structure.

Description:
RELATED APPLICATION DATA 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 12/957,808, filed Dec. 1, 2010, which is a continuation-in-part of U.S. patent application Ser. Nos. 12/846,621, filed Jul. 29, 2010, 12/846,644, filed Jul. 29, 2010, and 12/846,686, filed Jul. 29, 2010, the disclosures of which are each incorporated by reference herein in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    Embodiments of the invention relate generally to photovoltaic (PV) power generation systems, and more particularly to simplifying the installation of photovoltaic modules in large-scale arrays. 
       BACKGROUND OF THE INVENTION 
       [0003]    Typically, photovoltaic power generation systems are constructed by installing a foundation system (typically a series of posts or footings) on which is constructed a module structural support frame (typically constructed of elongated beams, brackets, tables or rails, and clips), and mounting individual photovoltaic modules to the support frame with fasteners, for example, fastening clips. This is a time-consuming process, which becomes increasingly inefficient with large-scale installations. 
         [0004]    More recently, cartridge designs have been developed, such as those disclosed in U.S. patent application Ser. Nos. 12/846,621 and 12/957,808 to Bellacicco, et al. A cartridge design, also sometimes referred to as a module carrier, permits pre-assembly of groups of photovoltaic modules onto a common frame structure which can be shipped as a unit to an installation site where they are installed as a unit on a support structure. The assembly of each cartridge, which generally involves manually mounting each photovoltaic module to the frame structure, can be consolidated at a factory. Once assembled, the cartridges can be shipped whole to an installation site and installed without the complicated and labor intensive procedures that were previously required on site to install individual photovoltaic modules. 
         [0005]    A cartridge design that is easily manufactured is desirable. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of backside of a photovoltaic module according to an exemplary embodiment. 
           [0007]      FIG. 2  is a perspective view of a photovoltaic module mounting rail according to an exemplary embodiment. 
           [0008]      FIG. 2A  is a perspective view of a photovoltaic module mounting rail blank according to an exemplary embodiment. 
           [0009]      FIG. 2B  is a perspective view of a photovoltaic module mounting rail blank according to an exemplary embodiment. 
           [0010]      FIGS. 3A and 3B  are respective top-down views of a completely and partially loaded cartridge according to an exemplary embodiment. 
           [0011]      FIG. 3C  is a top-down view of a completely loaded cartridge according to another exemplary embodiment. 
           [0012]      FIG. 4A  is a cross-sectional view of side beams of a cartridge frame according to an exemplary embodiment. 
           [0013]      FIG. 4B  is a cross-sectional view of the top and bottom beams of a cartridge frame according to an exemplary embodiment. 
           [0014]      FIG. 4C  is a cross-sectional view of side beams of stacked cartridges according to an exemplary embodiment. 
           [0015]      FIG. 4D  is an end view of the center beam of a cartridge frame according to an exemplary embodiment. 
           [0016]      FIG. 4E  is a cross-sectional view of a center beam of a cartridge frame according to an exemplary embodiment. 
           [0017]      FIG. 4F  is a perspective view of one end of a side beam of a cartridge frame according to an exemplary embodiment. 
           [0018]      FIG. 5A  is a top perspective view of a wiring structure for a cartridge frame according to an exemplary embodiment. 
           [0019]      FIG. 5B  is a cross-sectional view of a center beam of a cartridge frame according to an exemplary embodiment. 
           [0020]      FIG. 6  is a perspective view of a corner joining element of a cartridge frame according to an exemplary embodiment. 
           [0021]      FIG. 7  is a cross-sectional view of center and side beam of a cartridge frame showing a loaded photovoltaic module according to an exemplary embodiment. 
           [0022]      FIG. 7A  is a cross-sectional view of center and side beam of a cartridge frame showing a loaded photovoltaic module according to an exemplary embodiment. 
           [0023]      FIG. 7B  is a cross-sectional view of center and side beam of a cartridge frame showing a loaded photovoltaic module according to an exemplary embodiment. 
           [0024]      FIG. 8A  is a side view of a side beam of a cartridge frame and wheel assembly according to an exemplary embodiment. 
           [0025]      FIG. 8B  is an end view of a wheel assembly for a cartridge frame according to an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and which illustrate specific embodiments of the invention. These embodiments are described in sufficient detail to enable those of ordinary skill in the art to make and use them. It is also understood that structural, logical, or procedural changes may be made to the specific embodiments disclosed herein without departing from the spirit or scope of the invention. 
         [0027]      FIG. 1  illustrates the underside of a photovoltaic module  10  having a pair of mounting rails  12  installed thereon. The mounting rails  12 , one being shown in  FIG. 2 , are generally arranged spaced apart from each other so as to not impede conductors  17  exiting a module underside mounted cord plate  14 . The mounting rails  12  are arranged equidistantly from each other in a longitudinal direction. Although two mounting rails  12  are shown in  FIG. 1 , any number could be used depending on the configuration of photovoltaic module  10 . 
         [0028]    The mounting rails  12  are illustrated with one longitudinal side  7  down and another longitudinal side  7  up in  FIGS. 1 and 2 . Each mounting rail  12 , which is generally a hollow metallic structure, has two longitudinal sides  7 , two upstanding ends  9 , one closed back surface  19 , one open side  13 , and one or more mounting holes  16  in each of the upstanding ends  9  through which a fastener, such as, e.g., a screw, pin, bolt, or rivet, could pass. The open side  13  of the mounting rails  12  allows access for the fasteners as will be described in greater detail below. Two mounting holes  16  for each upstanding end  9  are shown in  FIG. 2 , but it should be understood that any number could be used, and further, mounting holes  16  can be threaded screw holes or holes provided with integral bolts. 
         [0029]    The mounting rails  12  are mounted to photovoltaic module  10  by applying an adhesive  15 , such as a polymer glue or very high adhesive bond tape, to one longitudinal side  7  of the mounting rail  12 , which faces the photovoltaic module  10  in  FIG. 1 , and pressing the mounting rail  12  to the photovoltaic module  10  in the direction of the arrows in  FIGS. 1 and 2 . Of course, it should be understood that the adhesive  15  could be applied to the underside of the photovoltaic module  10  instead of, or in addition to, the adhesive  15  applied to a longitudinal side  7  of the mounting rail  12 . In the embodiment shown in  FIG. 1 , the two mounting rails  12  are adhered to the photovoltaic module  10  such that the closed, back surfaces  19  of the mounting rails  12  face towards each other. In another embodiment, mounting rails  12  can be adhered such that the closed, back surfaced  19  of the mounting rails  12  face away from one another. It should also be understood that the adhesive  15  could be applied to either longitudinal side  7  of the mounting rail  12  as desired. 
         [0030]      FIGS. 2A and 2B  show mounting rail blanks  12   a, b  from which the mounting rails  12  of  FIGS. 1 and 2  can be formed. In one embodiment, shown in  FIG. 2A , each upstanding end  9  of  FIG. 2  is formed from a corresponding end tab  9   a  of the back surface  19  that is bent upwardly by 90° to the back surface  19  to align with longitudinal sides  7  that are also upwardly bent by 90° relative to back surface  19 . In one embodiment, the joint where the bent longitudinal sides  7  and the end tab  9   a  meet may be welded or otherwise fastened to one another. In another embodiment, the bent longitudinal sides  7  need not be welded or otherwise fastened to the tabs  9   a.    
         [0031]    In another embodiment shown in  FIG. 2B , each upstanding end  9  is a three-tab design formed from one end tab  9   a  of the back surface  19  that is bent at a 90° angle to the back surface  19  and two side tabs  7   a, b  of the longitudinal sides  7  that are bent at a 90° angle to the longitudinal sides  7 . The end tab  9   a  may be bent to overlap the side tabs  7   a, b  in one embodiment. In an alternative embodiment, the side tabs  7   a, b  may be bent to overlap the end tab  9   a.  In the embodiments, the mounting holes  16  may be formed through the upstanding end  9  such that they extend through all tabs that form the upstanding end  9  either before or after the sides and tabs  7 ,  7   a,b,    9   a  are bent into position. 
         [0032]      FIG. 3A  illustrates a completely loaded cartridge  1  with eight photovoltaic modules  10 , each with underside mounted rails  12 , mounted to a frame structure  20  in an array of rows and columns. In  FIG. 3A , an array of two columns and four rows of photovoltaic modules  10  is shown with the upper “sunny side” surface being shown. The cartridge  1  is mounted and installed on parallel cartridge mounting rails  21 . Mounting rails  21  may be provided on a ground or roof support structure. 
         [0033]      FIG. 3B  illustrates a cartridge  1  loaded with two modules  10 A,  10 B so that more detail of the frame structure  20  can be seen. The frame structure  20  comprises top and bottom beams  22   a,    22   b  and first side and second side beams  24   a,    24   b,  joined at the corners by corner joining elements  28  (which are shown in more detail in  FIG. 6 ). The cartridge  1  also comprises a center beam  26  mounted between the top and bottom beams  22   a,    22   b.  Each of the side beams  24   a,    24   b  as well as the center beam  26  has mounting ridges  32  for receiving and supporting opposite ends of each of the associated mounting rails  12  of a photovoltaic module  10 . The side beams  24   a,    24   b  each have one mounting ridge  32 , while the center beam  26  has two mounting ridges  32 , one on each of its opposite sides. 
         [0034]      FIG. 3B  shows a first photovoltaic module  1  OA in place between first side beam  24   a  and center beam  26  and a second photovoltaic module  10 B between the second side beam  24   b  and center beam  26 . Photovoltaic module  10 B is shown transparently, so that the corresponding pair of mounting rails  12  can be better seen to illustrate how a photovoltaic module  10  is mounted to the cartridge  1 . Module  10 B, when mounted, has the ends  9  of its associated mounting rails  12  positioned on the ridges  32  of the second side beam  24   b  and center beam  26 . Fasteners  18  are passed through the mounting holes  16  and into corresponding mounting holes  35  (shown in  FIG. 4D ) in the center beam  26  and second side beam  24   b.  As noted, the fasteners  18  may be screws, pins, bolts, or rivets. The fasteners  18 , e.g. screws, are received through the open side of the mounting rails  12  when the modules  10  are placed on the cartridge  1 . In this particular embodiment as noted above the rails  12  are hollow and open on one side  13  as illustrated in  FIG. 2 . The mounting holes  35  can be unthreaded holes, threaded screw holes, or holes provided with integral bolts provided on the first and second side beams  24   a,    24   b  and the center beam  26 . The mounting holes  35  on the first and second side beams  24   a,    24   b  and the center beam  26  are spaced lengthwise along the beams  24   a,    24   b,    26  so as to allow the rails  12  attached to the photovoltaic modules  10  to be properly installed on the frame structure  20 . 
         [0035]    In a completely loaded cartridge  1 , such as shown in  FIG. 3A , each photovoltaic module  10  is mounted between one of the first and second side beams  24   a,    24   b  and the center beam  26 . Of course, it should be understood that the lengths of the various beams  22   a,    22   b,    24   a,    24   b  and  26  can be modified to accommodate any size or number of photovoltaic modules  10 , or for a different mounting arrangement than that shown. Multiple center beams  26  can also be used, as is shown in  FIG. 3C , so as to permit the mounting of more than two columns of photovoltaic modules  10  on the cartridge  1 . 
         [0036]      FIGS. 4A ,  4 B,  4 C,  4 D, and  4 E show elements of beams  22   a,    22   b,    24   a,    24   b  and  26  in more detail.  FIG. 4A  shows a cross-section of the first and second side beams  24   a,    24   b  along line  4 A- 4 A of  FIG. 3B .  FIG. 4B  shows a cross section of an exemplary top and bottom beam  22   a,    22   b  along  4 B- 4 B of  FIG. 3B .  FIG. 4C  shows cross sections of stacked exemplary side beams  24   a  according to a disclosed embodiment.  FIG. 4D  shows a end view of the center beam  26 .  FIGS. 4E  shows a cross-section of center beam  26  along  4 E- 4 E of  FIG. 3B . Each of beams  22   a,    22   b,    24   a,    24   b  and  26  is generally hollow and constructed from a rolled metal, such as galvanized steel. A reinforced area  36  formed of folded over metal is provided at a bottom part of each beam  22   a,    22   b,    24   a,    24   b,    26  and extends the entire length of the beams to provide increased stability and torsion resistance. Of course, the reinforced area  36  could also be located at a top of beam  22   a,    22   b,    24   a,    24   b,    26 . Additionally, as noted above, each of the first and second side beams  24   a,    24   b  and center beam  26  have mounting ridges  32  in the form of protrusions that extend outward from and along the length of beams  24   a,    24   b,    26  to receive and support the module mounting rails  12 . The module mounting rails  12  rest on top of the mounting ridges  32  between beams  24   a,    24   b,    26 . 
         [0037]      FIG. 4A  shows an end part of a mounting rail  12  associated with a photovoltaic module  10  interfacing one of the side beams  24   a.  As can be seen in  FIG. 4A , a fastener  18  passes through mounting hole  16  in the upstanding end  9  of the mounting rail  12  and is driven in a direction S into a corresponding mounting hole  35  in the side beam  24   a.    
         [0038]    As is also shown in  FIGS. 4A and 4B , each of top and bottom beams  22   a,    22   b  and first side and second side beams  24   a,    24   b  also have an upwardly extending stabilizing flange  34  which is configured to engage the underside (in a direction D, as shown in  FIG. 4A ) of a corresponding top and bottom beam  22   a,    22   b  or first side and second side beam  24   a,    24   b  in another cartridge  1 . This permits cartridges  1  to be securely stacked, one atop another, following manufacturing and for transportation.  FIG. 4C  illustrates cartridge stacking in more detail, showing one side beam  24   a  stacked atop another side beam  24   a  of another cartridge  1 . The stabilizing flange  34 , which extends around substantially the entire outer rim of a cartridge  1 , further serves to protect around the periphery of the cartridge  1  and the photovoltaic modules  10  mounted on the cartridge  1 . 
         [0039]      FIG. 4D  shows a pair of mounting flanges  38  provided at each end of center beam  26 . The mounting flanges  38  each extend outward and perpendicularly from the beam  26  and have mounting holes  39  for affixing the center beam  26  to and between the top and bottom beams  22   a,    22   b  with fasteners. 
         [0040]    In another embodiment, shown in the exemplary beam  24   d  in  FIG. 4F , stabilizing flange  34   a  and/or mounting ridge  32   a  may terminate at a distance E from the end of a beam  24   d  to permit an oversized corner joining element to slide over the associated end of the beam  24   d.  In order to facilitate this, the stabilizing flange  34   a  and/or mounting ridge  32   a  are separate elements affixed to the beam  24   d,  rather than the integral elements as shown, for example, in  FIG. 4A . Corresponding mounting holes  37  for alignment with the holes  38  of joining elements  28  are also provided on the exemplary beam  24   d.    
         [0041]    In one embodiment shown in  FIGS. 5A and 5B , the center rail may act as a wiring conduit, allowing branches  41  from a common electrical bus  42  that extends along and within the center beam  26  of the cartridge  1  to connect to each photovoltaic modules  10  through connector blocks  43 .  FIG. 5B  is a cross-section of the center beam  26  along line  5 B- 5 B of  FIG. 5A . The common electrical bus  42  acts to route the electricity generated by each photovoltaic module  10  on the cartridge  1  to a common attachment point  44 . In this embodiment, wiring access holes  40  are formed on both sides of the center rail, as shown in  FIG. 5B , to allow the electrical bus  42  to access the conductors  17  for each photovoltaic module  10  mounted to either side of the center beam  26  as shown in  FIGS. 3A and 3B . 
         [0042]    The top and bottom beams  22   a,    22   b  and first side and second side beams  24   a,    24   b  are joined at their corners by corner joining elements  28 , shown in  FIG. 6 . The ends of the corner joining element  28  are configured to be inserted into the ends of each of one of the top or bottom beams  22   a,    22   b  and first side or second side beams  24   a,    24   b  and secured thereto by fasteners  18  having a shaft inserted through holes  38 . In one embodiment, shown in  FIG. 6 , the corner joining element  28  is a solid element. In another embodiment, the corner joining element  28  is hollow. In this embodiment, the corner joining element  28  may be undersized at its ends compared to the side and bottom beams  22   a,    22   b,    24   a,    24   b  so that the corner joining element can be inserted into the beams  22   a,    22   b,    24   a,    24   b.  In the alternative, the corner joining element  28  may be oversized compared to the side and bottom beams  22   a,    22   b,    24   a,    24   b  and hollow, so that the beams  22   a,    22   b,    24   a,    24   b  can be inserted into the corner joining element  28 . 
         [0043]      FIG. 7  shows an alternate configuration for a center beam  26 A that employs mounting posts  35 A instead of mounting holes  35 . In use, the holes  16  of one end of the rails  12  of a photovoltaic module are slid over the posts  35 A. Consequently, only one end  9  of each mounting rail  12  needs to be secured to the cartridge  1  with one or more fasteners  18 .  FIG. 7  also shows an alternative way to fasten rails  12  to the cartridge  1 . Openings  33  may be provided in the walls of a beam (e.g. side beam  24   b  being shown in  FIG. 7 ) through which fasteners  18  can be inserted in the direction S to pass into the holes  16  provided in the ends  9  of the rails  12 . In this manner, a cartridge  1  can be assembled without having to pass any fasteners  18  into the cartridge  1  from the underside of the cartridge  1 . In another embodiment shown in  FIG. 7A , the mounting posts  35 B may be employed on a side beam, such as side beam  24   d  and the fasteners  18  employed on the center beam  26 B. In a third embodiment shown in  FIG. 7B , the mounting posts  35 C may be employed on one end of the mounting rails  12   a  and configured to be inserted to respective mounting holes on the center beam  26 C. In the embodiment shown in  FIG. 7B , fasteners  18  may be used on the second end of the mounting rail  12   a  as described with respect to  FIG. 7 . 
         [0044]      FIGS. 8A and 8B  show, from a side view and end view respectively, a wheel assembly  50  that may be used as an attachment structure to allow the cartridge to slide along the cartridge mounting rails  21 , shown in  FIG. 3A . This enables the cartridge  1  to easily slide in a mounted position along cartridge mounting rails  21  to an installed position. The wheel assembly  50  is mounted to the side rails (e.g. side rail  24   a ) as is shown in  FIG. 8A  at locations corresponding to that of the cartridge mounting rails  21 . If two mounting rails  21  are provided, four wheel assemblies  50 , two on each side of cartridge  1  are provided. The cartridge mounting rails  21  and module mounting rails  12  are configured as can be seen in one embodiment in  FIGS. 3A and 3B  so that the wheel assemblies  50  are provided between module mounting rails  12  such that sufficient clearance exists between the underside of the photovoltaic module and the wheel assembly  50  to permit the wheel assembly&#39;s operation. In one embodiment, the wheel assembly  50  is assembled from a mounted portion  51 , which is affixed to the side rail  24   a,  and a hinged portion  52 , which is connected to the wheel  53 . This construction enables the wheel assembly  50  to be placed in a storage position to enable the cartridge  1  to be stacked on other cartridges. When the cartridge  1  is ready to be installed, the hinged portion  52  is moved from the storage position and locked into a mounting position such that the mounted portion  51  rests on the hinged portion  52 , which wraps underneath the mounted portion  51 , to prevent the side rail  24   a  from resting on the cartridge mounting rail  21 . In other embodiments, the wheel assembly  50  may be mounted to the outside of the side rail  24   a  or may be mounted below the mounting ridge  32 . 
         [0045]    As is shown in  FIG. 8B , the wheel  53  is configured to follow a channel  55  in the rail  21 . The wheel assembly  50  also includes a wheel bracket  54  that wraps around the rail  21  to prevent the cartridge  1  from lifting off of the rail  21 , but allow the wheel assembly  50  to slide over the mounting rail supports  56  that are used to affix the mounting rails  21  to the ground, a roof, or other structure that provides a foundation. It can be appreciated that other attachment structures from the wheel assembly  50  may be used, such as ball bearings or low friction surfaces, as described in U.S. patent application Ser. No. 12/846,646. 
         [0046]    The above described cartridges  1  ( FIGS. 3A and 3B ),  1 B ( FIG. 3C ) can be easily machine assembled, although manual assembly is also possible, in a process which has the photovoltaic modules  10  with the mounting rails  12  installed as an array of modules atop an assembled cartridge  1 . Because each photovoltaic module  10  is individually attached to the cartridge  1  by its own mounting rails  12 , selective installation and removal of a each photovoltaic module is possible simply by attaching or detaching the corresponding fasteners  18 . Advantageously, the cartridges  1  ( FIGS. 3A ,  3 B) or  1 B ( FIG. 3C ) do not have to be disassembled to replace a single photovoltaic module  10  in the field. 
         [0047]    While several embodiments have been described in detail, it should be readily understood that the invention is not limited to the disclosed embodiments. Rather the embodiments can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described. Although certain features have been described with some embodiments of the cartridge, such features can be employed in other embodiments of the cartridge as well. Accordingly, the invention is not limited by the foregoing description, but is only limited by the scope of the appended claims.