Abstract:
One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame having at least a top member and a bottom member. A plurality of alignment features are included on the top member of each frame, and a plurality of alignment features are included on the bottom member of each frame. Adjacent photovoltaic modules are interlocked by the alignment features on the top member of a lower module fitting together with the alignment features on the bottom member of an upper module. Other embodiments, features and aspects are also disclosed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present disclosure relates to photovoltaic modules and the transportation and installation thereof. 
         [0003]    2. Description of the Background Art 
         [0004]    Photovoltaic cells, also known as “solar cells,” are devices for converting solar radiation to electrical energy. Photovoltaic cells are typically arranged into an array and packaged as a photovoltaic (PV) module, also known as a “solar module.” 
         [0005]    Photovoltaic modules may also be installed in solar collector arrays with capacities from a few kilowatts to hundreds of kilowatts, or more. These arrays are typically installed where there is a reasonably flat area with exposure to the sun for significant portions of the day. 
         [0006]    A substantial portion of the cost associated with solar collector arrays relates to the transportation and installation of the photovoltaic modules. Hence, it is highly desirable to improve methods and apparatus of transporting and installing photovoltaic modules. 
       SUMMARY 
       [0007]    One embodiment relates to an arrangement of photovoltaic modules configured for transportation. The arrangement includes a plurality of photovoltaic modules, each photovoltaic module including a frame having at least a top member and a bottom member. A plurality of alignment features are included on the top member of each frame, and a plurality of alignment features are included on the bottom member of each frame. Adjacent photovoltaic modules are interlocked by the alignment features on the top member of a lower module fitting together with the alignment features on the bottom member of an upper module. 
         [0008]    Another embodiment relates to a photovoltaic module. The module includes an array of solar cells and a frame for supporting the array of solar cells. The frame includes a top member and a bottom member connected by a side member. A plurality of alignment features are included on the top member, and a plurality of alignment features are included on the bottom member. The alignment features on the bottom member are configured to couple with the alignment features on the top member of another module. 
         [0009]    Other embodiments, aspects and features are also disclosed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  depicts a first example solar collector arrangement with an array of photovoltaic modules supported by a frame structure. 
           [0011]      FIG. 2  depicts a second example solar collector arrangement with an array of photovoltaic modules supported by a roof. 
           [0012]      FIG. 3  depicts a first conventional packaging solution for transporting photovoltaic modules. 
           [0013]      FIG. 4  depicts a second conventional packaging solution for transporting photovoltaic modules. 
           [0014]      FIG. 5  depicts a frame for a photovoltaic module with a stacking feature in accordance with an embodiment of the invention. 
           [0015]      FIG. 6  shows a first profile of a module frame with an alignment feature in accordance with an embodiment of the invention. 
           [0016]      FIG. 7  shows a second profile of a module frame with an alignment feature in accordance with an embodiment of the invention. 
           [0017]      FIG. 8  depicts an exemplary alignment feature attached to a module frame in accordance with an embodiment of the invention. 
           [0018]      FIG. 9  depicts stack of photovoltaic modules which are interlocked with each other in accordance with an embodiment of the invention. 
           [0019]      FIG. 10  shows a profile of a module frame in an alternate embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    In the present disclosure, numerous specific details are provided, such as examples of apparatus, process parameters, materials, process steps, and structures, to provide a thorough understanding of embodiments of the invention. Persons of ordinary skill in the art will recognize, however, that the invention can be practiced without one or more of the specific details. In other instances, well-known details are not shown or described to avoid obscuring aspects of the invention. 
         [0021]    Example Solar Collector Arrangements 
         [0022]      FIG. 1  depicts a first example solar collector arrangement  10 . In this view, a single row  11  is shown, but the array can comprise several rows  11  joined end to end, and can comprise any number of such rows side by side. A row of solar panels  14 , i.e., photovoltaic modules, is attached onto a torsion tube  12 . 
         [0023]    In this example arrangement, the row has sixty panels or modules  14 , i.e., thirty sets of two modules. There are four vertical pier tubes  16 , which can be round or square cross section, as desired, each supported in the earth. 
         [0024]    At a top end of each pier tube  16  may be a pier cap weldment  20 , which may have a transverse square tubular sleeve that fits the profile of the torsion tube  12 . The pier caps  20  on the pier tubes  16  may be aligned so that the torsion tube  12  threads through them. There may be multiple support rails or panel rails  22  attached onto the torsion tube  12 , and these rails  22  may be arranged across tube at right angles to the tube axis and may be spaced apart the width of one panel or module  14 . 
         [0025]      FIG. 2  depicts a second example solar collector arrangement  50  with an array of photovoltaic modules  52  supported by a roof. As shown, the modules  52  may be installed flush or relatively close to a roof plane  54 . 
         [0026]    Conventional Packaging of Solar Modules for Shipment 
         [0027]    Photovoltaic modules are typically packed and shipped in cardboard boxes. As depicted in  FIG. 3 , multiple boxes  302  are generally stacked on top of each other and shipped together as a unit. The stack of boxes  302  are typically strapped to a wood pallet  304  and shipped together as a unit. Two solar modules may be included in each cardboard box with a cardboard sheet between them. 
         [0028]    Another packaging solution for solar modules is depicted in  FIG. 4 . This solution uses corner elements  402  to support and stack multiple modules  404  on top of each other. The stack with the corner elements is then strapped to a wood pallet  406  and shipped together as a unit. 
         [0029]    Disadvantages and Inefficiencies with Conventional Packaging Solutions 
         [0030]    Applicants have determined that these conventional packaging solutions have disadvantages and inefficiencies. 
         [0031]    The conventional solution of packaging the modules in cardboard boxes results in extra cost for the boxes. In addition, there is substantial work needed to unpack the modules and recycle the boxes at the installation site. For example, in a large installation, there is typically a worker dedicated to this task on unpacking and recycling boxes. Furthermore, the cardboard material takes up space in a stack of modules being shipped and so reduces the shipping density of the modules. A lower shipping density means that fewer modules may be shipped in a fixed volumetric size of a shipping container. 
         [0032]    The packaging solution which uses corner elements results in substantial space between modules, both horizontally and vertically, in a shipping stack. Hence, this solution also results in a relatively low shipping density. Furthermore, there is also the cost of the corner elements, the need to dispose of or recycle the corner elements at the installation site, and in some cases return shipping of the corners to the manufacturer. 
         [0033]    Efficient Packaging Solution for Transporting Solar Modules 
         [0034]      FIG. 5  depicts (in perspective view from the top) a frame for a photovoltaic module with a stacking feature in accordance with an embodiment of the invention. Exemplary profiles for the frame are described below in relation to  FIGS. 6 and 7 . 
         [0035]    As seen in  FIG. 5 , the module frame  502  may be a rectangular frame which is configured to frame and support a photovoltaic module. (The module is configured in the framed area  504 .) In accordance with an embodiment of the present invention, the module frame includes (male) alignment features  506  which protrude from the top surface of the frame. In addition, there are corresponding holes (female alignment features) on the bottom surface of the frame. As discussed further below, these alignment features  506  enable an advantageous packaging solution for the transportation of the photovoltaic modules. 
         [0036]    In one implementation, an alignment feature  506  may be included on each side of the top surface of the frame and positioned relatively close to a corner of the frame. Other implementations may position the alignment features  506  at different locations on the top surface of the frame. 
         [0037]      FIG. 6  shows a first profile of a module frame with an alignment feature in accordance with an embodiment of the invention. As shown, the frame includes a side member  602  which attaches to and separates a top member  608  and a bottom member  604 . A slot  606  towards the top of the frame is configured to hold and support the photovoltaic cells within the frame. (The top faces the sunlight after installation of the module.) The photovoltaic cells form a silicon layer  624  which may be sandwiched between a glass layer  622  and a polymer layer  626 . 
         [0038]    In accordance with an embodiment of the invention, male alignment features (for example, pins or raised track)  506  are included at selected positions to the top surface of the frame. The alignment features  506  may be inserted into the top surface of the frame during the frame manufacturing process. The inserted alignment features  506  preferably remain above and do not break the glass layer  622  so as to maintain the integrity of the enclosure for the silicon cells. Alternatively, the alignment features  506  may be formed during the extrusion of the frame. 
         [0039]    Corresponding female alignment features (for example, holes or grooves)  610  are also formed in the bottom member of the frame. These female alignment features  610  are formed on the bottom area of the frame at locations which correspond to (and in case of pins and holes, coaxially align with) the locations of the male alignment features  506  on the top area of the frame. As such, with these male and female alignment features, the module frames may be directly stacked on each other in a secure and interlocked manner. In one embodiment, one or more of the corresponding holes may also function as drain holes at the bottom of the frame. 
         [0040]      FIG. 7  shows a second profile of a module frame with male and female alignment features in accordance with an embodiment of the invention. As shown, the frame includes a side member  702  which is coupled to a top member  708  and bottom members  704  and  705 . A slot  706  towards the top of the frame is configured to hold and support the photovoltaic cells within the frame. The photovoltaic cells form a silicon layer  724  which may be sandwiched between a glass layer  722  and a polymer layer  726 . Also shown are channels  712  which may be used to provide an anchor for self-tapping screws. 
         [0041]    In accordance with an embodiment of the invention, male alignment features  506  are included at selected positions to the top surface of the frame. The male alignment features (for example, pins or raised tracks)  506  may be inserted into the top surface of the frame during the frame manufacturing process. The inserted alignment features  506  preferably remain above and do not break the glass layer  722  so as to maintain the integrity of the enclosure for the silicon cells. Alternatively, the alignment features  506  may be formed during the extrusion of the frame. 
         [0042]    Corresponding female alignment features (for example, holes or grooves)  710  are also formed in the bottom member of the frame. These female alignment features  710  are formed on the bottom area of the frame at locations which correspond to (and in the case of pins and holes, coaxially align with) the locations of the male alignment features  506  on the top area of the frame. As such, with these male and female alignment features, the module frames may be directly stacked on each other in a secure and interlocked manner. In one embodiment, one or more of the corresponding holes may also function as drain holes at the bottom of the frame. 
         [0043]      FIG. 8  depicts an exemplary alignment feature  804  attached to a module frame  802  in accordance with an embodiment of the invention. As shown, this (male) alignment feature  804  may comprise a protruding portion  806  that rises above the top surface of the frame and an embedded portion  808  that secures it to the frame. 
         [0044]    In this particular embodiment, the alignment feature  804  is implemented using a self-clinching fastener. The fastener may be installed in the top surface of the frame by drilling a hole at the location for the alignment feature and then inserting the self-clinching portion of the fastener into the drilled hole using an automated press. 
         [0045]    In an alternative embodiment, the embedded portion may be a screw which may be screwed into a screw hole formed in the frame. In such an embodiment, the alignment feature may be removed, if desired, after un-stacking the modules. Other means may also be used for attaching the alignment feature to the module frame. 
         [0046]    The protruding portion  806  is preferably tall enough to engage the adjacent frame that is stacked on top of it. Preferably, the protruding portion is also short enough so that chance of breakage from a side force is low and so that the protruding feature does not interfere with movement of the solar module. In addition, the protruding portion is preferably sufficiently short so as to avoid undesirable shading of the photovoltaic module during operation. 
         [0047]      FIG. 9  depicts stack of photovoltaic modules  902  which are interlocked with each other in accordance with an embodiment of the invention. Advantageously, the photovoltaic modules  902  may be stacked directly on each other and held together, in part, using the male and female alignment features to interlock adjacent modules. The interlocked stack of modules  902  may be strapped to a wood pallet  904  and shipped together as a unit. Protective cardboard sheets may be used on the outside of the stack, but cardboard boxes are not used to hold the modules. 
         [0048]    Such an interlocked stack of solar modules is efficient because it provides for dense packing of the modules during transportation. This enables a greater number of modules to be shipped in a same volumetric space compared to prior packaging techniques. The wasted space taken by the cardboard boxes, or created by the corner elements, is avoided. 
         [0049]    In addition, the material cost is reduced as neither cardboard boxes nor corner elements are needed as in the prior packaging techniques. Labor is also reduced as the modules need not be unpacked from the boxes, and the boxes or corner elements need not be discarded, recycled, or shipped. 
         [0050]      FIG. 10  shows a profile of a module frame in an alternate embodiment of the invention. As shown, the frame includes a side member  1002  which attaches to and separates a top member  1008  and a bottom member  1004 . A slot  1006  towards the top of the frame is configured to hold and support the photovoltaic cells within the frame. The photovoltaic cells form a silicon layer  1024  which may be sandwiched between a glass layer  1022  and a polymer layer  1026   
         [0051]    In accordance with an embodiment of the invention, a lip  1009  is included at the outer edge of the bottom of the frame. The lip  1009  is configured so as to form inner corners  1010  with the bottom surface of the frame. The inner corners  1010  fit onto and interlock with the outer corners  1012  at the top of the adjacent frame in the stack. The outer corners  1012  are formed by the side member  1002  and a top surface of the frame. 
         [0052]    While specific embodiments of the present invention have been provided, it is to be understood that these embodiments are for illustration purposes and not limiting. Many additional embodiments will be apparent to persons of ordinary skill in the art reading this disclosure. 
         [0053]    For example, an alternate embodiment may provide a female alignment feature on the top surface of a frame, and a corresponding male alignment feature on the bottom surface of the frame. Such features would also enable advantageous direct stacking of the photovoltaic modules for transportation.