Abstract:
A method of manufacturing a photovoltaic roofing tile for installing on a roof surface and converting solar energy into electrical energy includes the steps of forming a generally flexible photovoltaic laminate, the laminate including a photovoltaic layer including plurality of electrically interconnected photovoltaic cells and a photovoltaic circuit electrically connecting the photovoltaic cells, inserting the laminate into a tile mold and injecting a molten thermoplastic material into the tile mold to form and fixedly attached a tile base to the laminate.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 60/942,151 filed Jun. 5, 2007 entitled “Solar Roofing Connector System”, U.S. Provisional Patent Application No. 60/942,112 filed Jun. 5, 2007 entitled “Solar Roofing Tile Connection System” and U.S. Provisional Patent Application No. 60/942,124 filed Jun. 5, 2007 entitled “Solar Roofing Tile”. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to a method of manufacturing a solar roofing tile, specifically a method of manufacturing a solar roofing tile in which a photovoltaic cell and circuitry is laminated and is then inserted molded into a base tile substrate. 
         [0003]    Photovoltaic cells, formed of single crystal and/or thin film sub-modules, convert solar energy into electrical energy. Various systems have been introduced to adapt photovoltaic cells for installation onto commercial and residential roofs. Because roofing tiles are subject to harsh environmental conditions, photovoltaic modules were originally comprised of ridged materials such as metal and glass to prevent or at least postpone the hassle and expense of photovoltaic tile replacement. Such photovoltaic modules, however do not provide for a visually consistent roof and detracted from the appearance of the home or business. 
         [0004]    Aesthetics is generally a high priority for developers and homeowners in the market for a new roof. Conventional photovoltaic modules are generally arranged in thick raised boxes with a shinny outer surface. In addition to being conspicuous, conventional photovoltaic modules required separate installation requiring the user to drill holes or other attachment means to the roof creating additional expense and potential leakages. 
         [0005]    Roofing products have been developed that integrate the photovoltaic cells directly into individual roofing tiles or shingles which are assembled to form an integrated solar roofing system. Laminated photovoltaic modules have been introduced to produce thinner and more integrated solar roofing systems but attempts are not visually consistent with inactive tiles, are subject to de-lamination or detachment, and require special installation steps. 
         [0006]    There is therefore a need to provide an improved integrated photovoltaic tile that has an appearance and installation similar to adjacent inactive tiles to provide for an easy to install, visually seamless roof. Additionally, the photovoltaic tiles must be sufficiently durable to withstand de-lamination or detachment and wind and water damage caused by harsh weather conditions. Ultimately there is a need to provide a photovoltaic tile that has a similar appearance, strength characteristics, and installation method of a conventional roofing product. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    Briefly stated, the present invention is directed to a method of manufacturing a photovoltaic roofing tile for installing on a roof surface and converting solar energy into electrical energy. The method includes the steps of forming a generally flexible photovoltaic laminate, the laminate including a photovoltaic layer including plurality of electrically interconnected photovoltaic cells and a photovoltaic circuit electrically connecting the photovoltaic cells, inserting the laminate into a tile mold and injecting a molten thermoplastic material into the tile mold to form and fixedly attached a tile base to the laminate. 
         [0008]    In another aspect, the invention is directed to a method of manufacturing a photovoltaic roofing tile for installing on a roof surface and converting solar energy into electrical energy. The method includes the steps of forming a generally flexible photovoltaic laminate via a vacuum laminate process, the laminate including a photovoltaic layer including plurality of electrically interconnected photovoltaic cells capable of receiving solar energy and a photovoltaic circuit electrically connecting the photovoltaic cells, first and second laminate sheets sandwiching and sealing the photovoltaic layer, mounting a back sheet to the laminate, inserting the laminate into a tile mold and injecting a molten thermoplastic into a second side of the tile mold to form a base tile, the thermoplastic contacting and fixing the base tile to the back sheet. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0009]    The foregoing summary, as well as the following detailed description of a preferred embodiment of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings an embodiment which is presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings: 
           [0010]      FIG. 1  is a top perspective view of an installed integrated solar roofing system in accordance with the preferred embodiment of the present invention partially cut away to show the underlying battens and female connectors; 
           [0011]      FIG. 2  is a top perspective view of a photovoltaic roofing tile of the integrated solar roofing system shown in  FIG. 1 ; 
           [0012]      FIG. 3  is an exploded perspective view of a photovoltaic laminate of the photovoltaic roofing tile shown in  FIG. 2 ; 
           [0013]      FIG. 4  is a perspective view of a mold for manufacturing the photovoltaic roofing tile shown in  FIG. 2 ; 
           [0014]      FIG. 5  is a perspective view of a non-photovoltaic roofing tile of the integrated solar roofing system shown in  FIG. 1 ; 
           [0015]      FIG. 6  is an exploded perspective view of the non-photovoltaic roofing tile shown in  FIG. 5 ; 
           [0016]      FIG. 7  is an exploded perspective view of the female connectors and battens shown in  FIG. 1 ; 
           [0017]      FIG. 8  is a top perspective view of the assembled female connectors and battens shown in  FIG. 1  with the photovoltaic and non-photovoltaic tiles removed; 
           [0018]      FIG. 9  is a top perspective view of female connectors and solar roofing battens shown in  FIG. 1  during installation using a batten sheet; 
           [0019]      FIG. 10  is an enlarged top perspective view of a female connector extending from a batten shown in  FIG. 1 ; 
           [0020]      FIG. 11  is a bottom perspective view of the female connector and batten shown in  FIG. 10 ; 
           [0021]      FIG. 12  is a rear cross-sectional perspective view of the female connector and batten shown in  FIG. 10  taken along line  12 - 12  in  FIG. 10 ; 
           [0022]      FIG. 13  is a side cross-sectional perspective view of the female connector shown in  FIG. 10  taken along line  13 - 13  in  FIG. 10 ; 
           [0023]      FIG. 14  is a side elevational partial cross section view of a photovoltaic roofing tile, batten and female connector shown in  FIG. 1  just prior to installation of the photovoltaic roofing tile; and 
           [0024]      FIG. 15  is a side elevational partial cross section view of the photovoltaic tile, batten and female connector shown in  FIG. 14  after installation of the photovoltaic tile. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0025]    Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “lower” and “upper” designate directions in the drawings to which reference is made. The words “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of an integrated solar roofing tile in accordance with the present invention, and designated parts thereof. Unless specifically set forth herein, the terms “a”, “an” and “the” are not limited to one element but instead should be read as meaning “at least one”. The terminology includes the words noted above, derivatives thereof and words of similar import. 
         [0026]    Referring to  FIG. 1 , the integrated solar roofing system, generally designated  10 , is used to generate electricity from solar energy on a roof or roof surface  20  of a residential or a commercial building  22 . The integrated solar roofing system  10  is comprised of active or photovoltaic roofing tiles  12  and inactive or non-photovoltaic roofing tiles  14 . In  FIG. 1 , the photovoltaic roofing tiles  12  are shown having a phantom interior outline designating a photovoltaic layer  42 . However, the photovoltaic roofing tiles  12  preferably have the same or a similar appearance to the non-photovoltaic roofing tiles  14  and the variation in appearance in the drawings is for demonstrative purposes only. The photovoltaic roofing tiles  12  have the same or a similar appearance and configuration to the non-photovoltaic roofing tiles  14  but the photovoltaic roofing tiles  12  include at least one photovoltaic cell  16  ( FIG. 3 ) for generating electricity. The photovoltaic roofing tiles  12  are grouped in an area on the roof  20  that is a desired area for generating electricity. The area could be small, involving only a few photovoltaic roofing tiles  12  or the entire roof  20  depending on cost, location of the roof  20  relative to the sun and obstacles such as trees or a neighboring building blocking the sun. For example, most users in North America may choose to place the photovoltaic roofing tiles  12  only on the south facing side of a roof  20  because of the extended exposure from the south due to the earth&#39;s tilt relative to the sun. The photovoltaic roofing tiles  12  and the non-photovoltaic roofing tiles  14  preferably have an oscillating or curved shape to resemble conventional ceramic roof tiles. However, the photovoltaic roofing tiles  12  and the non-photovoltaic roofing tiles  14  may be formed in any shape such as a flat slate-like tile for example. 
         [0027]    Referring to  FIGS. 2-4 , each photovoltaic roofing tile  12  is preferably comprised of a tile base  18  which is constructed of building code approved material. The tile base  18  has a sun or first side  18   a , a roof or second side  18   b , an upper or top edge  18   c , a lower or bottom edge  18   d , a first lateral side  18   e  and a second lateral side  18   f . The tile base  18  is preferably constructed of an inserted molded polypropylene material, as discussed further below but the tile base  18  may be constructed of any suitable roofing material such as authentic slate, authentic ceramic tile, authentic cement tile, metal roofing, asphalt roofing, Elastocast (BASF), Bayflex (Bayer Material Science), Zytrel and/or Hytrel (Dupont). The tile base  18  may also be metallic, mineral, organic, polymeric, or a nondisclosed composite material. 
         [0028]    The tile base  18  preferably includes at least one and preferably a pair of recessed space apart nail targets  24  located toward the top edge  18   c  of the tile base  18 . Each nail target  24  preferably has a flat base  24   a  to provide a large surface in direct contact with a batten  26  ( FIG. 1 ) and helps to prevent the photovoltaic roofing tile  18  from lifting from the roof surface  20  in heavy winds. The nail target  24  preferably also includes a raised nail hole  24   b . The nail hole  24   b  is raised to help prevent any water that may have entered the recessed nail target  24  from entering the nail hole  24 . The tile base  18  further preferably includes at least one and preferably a pair of spaced apart, spring biased batten latches  28  proximate the top edge  18   c  and preferably spaced alternately between the nail targets  24  for temporarily and releasably engaging with a batten  26  during installation to hold the photovoltaic roofing tile  12  in place until the photovoltaic roofing tile  12  is more permanently secured to the batten  26  as described in further detail below. The batten latches  28  preferably each have a general Z-shape (in side view, see  FIG. 14 ) with a longer proximal end  28   a  that is attached to the tile base  18  (see  FIGS. 14 and 15 ). The batten latches  28  are each preferably upwardly angled at least at the distal end  28   b  of each batten latch  28 . The distal end  28   b  at least partially extends away from the tile base  18  further than the lowest point of the tile base  18 . The batten latches  28  are each spring biased such that the distal end  28   b  is capable of being urged upwardly and into a batten latch recess  28   c  (See  FIG. 2 ) within the tile base  18  such that the batten latch  28  does not extend past the tile base  18 . The batten latch  28  is preferably molded of the same or similar material as the tile base  18  and has a relatively thin proximal end  28   a  such that the batten latch  28  may be broken free from the tile base  18  as described further below. Though it is preferred that the batten latches  28  are molded of the same or similar material as the tile base  18 , the batten latches  28  may be molded of a different material such as metal and either insert molded or otherwise later installed or assembled to the tile base  18 . The batten latches  28  and the recessed nail targets  24  are preferably configured such that when the photovoltaic roofing tiles  12  are stacked on top of one another during shipping and storage, the downwardly projecting portions of the recessed nail targets  24  and the batten latches  28  are received within the recessed nail targets  24  and the batten latches  28  respectively of the photovoltaic roofing tile  12  directly below such that the photovoltaic roofing tiles  12  are nestable and form a compact stack. The compactness of the stacked photovoltaic roofing tiles  12  allows for more photovoltaic roofing tiles  12  to be shipped and/or stored on a palette (not shown) and occupy a space similar in size to what a stack of conventional roof tiles (not shown) would occupy. 
         [0029]    A first ridge  30  preferably extends away from the first side  18   a  of the tile base  18  proximate the top edge  18   c . A second ridge  32  preferably extends away from the second side  18   b  of the tile base  18  proximate the bottom edge  18   d . The first and second ridges  30 ,  32 , act as dams or barriers when the photovoltaic roofing tiles  12  are installed to prevent wind driven rain or moisture from extending beyond and eventually underneath the overlapping photovoltaic roofing tiles  12 . The tile base  18  also preferably includes an upwardly facing grove  34  on the first side  18   a  of the tile base  18  proximate the first lateral side  18   e  and a correspondingly shaped downwardly facing groove  36  on the second side  18   b  proximate the second lateral side  18   f . The upwardly facing grooves  34  mate with the downwardly facing grooves  36  during installation such that the downwardly facing grooves  36  overlap the upwardly facing grooves  34  allowing an overlap of the second lateral side  18   f  a first overlap distance D 1  to overlap the first lateral side  18   e  of an adjacent photovoltaic roofing tile  12  as the photovoltaic roofing tiles  12  are installed from left to right along the roof surface  20 . The orientation of the upwardly facing grooves  34  may be switched with the downwardly facing grooves  36  such that the first lateral side  18   e  of the photovoltaic roofing tile  12  overlaps the second lateral side  18   f  of an adjacent photovoltaic roofing tile  12 . 
         [0030]    Referring to  FIGS. 2 ,  3  and  4 , each photovoltaic roofing tile  12  includes a thin generally flexible photovoltaic laminate  38  fixedly mounted to the first side  18   a  of the tile base  18 . The laminate  38  is comprised of several encapsulated layers sandwiching the thin film photovoltaic cell(s)  16  and connected circuitry  40 . The circuitry  40  is preferably comprised of a tin/silver copper or simply copper bus (not shown) with various solder/flux combinations. The circuitry  40  includes first and second terminal ends  40   a ,  40   b  that extend from the laminate  38  along a contact tab  56 . The photovoltaic cells  16  and circuitry form a photovoltaic layer  42 . The photovoltaic layer  42  is sandwiched between a first laminate sheet  44  and a second laminate sheet  46 . The first and second laminate sheets  44 ,  46  are preferably constructed from but not limited to ETFE fluorinated polymer Tefzel, Aklar, silicone oxide or any other water vapor barrier layers such as glass. The first laminate sheet  44  allows light into the photovoltaic cells  16  while providing a protective cover for the photovoltaic layer  42 . The first laminate sheet  44  is preferably textured or otherwise treated to avoid an overly shiny or reflective surface and to better conceal the appearance of the photovoltaic layer  42 . The first and second laminate sheets  44 ,  46  are preferably laminated to opposing sides of the photovoltaic layer  42  by first and second EVA laminate adhesive layers  48 ,  50 . The bottommost layer of the photovoltaic laminate  38  is preferably an appliqué layer or back sheet  52  constructed of a polypropylene material or any suitable material such as EPE (ethyl vinyl acetate (EVA)/polyester/EVA). The back sheet  52  may be mounted to the second laminate sheet  44  by a third adhesive layer  54 . The back sheet  52  prevents the hot material injected during molding of the tile base  18  from damaging the photovoltaic laminate  38 . The first laminate sheet  44  and the first adhesive layer  48  preferably include a first laminate tab  44   a  and a first adhesive tab  48   a  respectively which each extend over the entire length of the contact tab  56 . The second and third adhesive layers  50 ,  54 , the second laminate sheet  46  and the back sheet  52  have a second adhesive tab  50   a , a third adhesive tab  54   a , a second laminate tab  46   a  and a back sheet tab  52   a  respectively that preferably extend only partially along the contact tab  56  until the contact tab  56  reaches the top edge  18   c  of the tile base  18  such that a distal end of the first and second terminal ends  40   a ,  40   b  is exposed toward the second side  18   b  of the tile base  18  or toward the roof surface  20 . However, the first and second terminal ends  40   a ,  40   b  may be left uncovered in any direction on the contact tab  56  or in any manner such as cutting slots or holes to leave at least a portion of the first and second terminal ends  40   a ,  40   b  following the lamination process without the need for further manufacturing steps and is sufficient to allow for an electrical connection with the photovoltaic layer  42  as described further below. 
         [0031]    The laminate  38  is preferably manufactured via a vacuum lamination process where a specific cycle of heat, vacuum, and pressure is applied to produce a flexible but durable laminate that provides outdoor and mechanical and environmental protection to the photovoltaic cell(s)  16 . The photovoltaic laminate  38  is formed by assembling the photovoltaic layer  42  between the first and second laminate sheets  44 ,  46 , with or without the first and second adhesive layers  48 ,  50  and then placing the stack in a vacuum laminator (not shown). Preferably, but not limiting, a platen (not shown) is set at 150° C. For approximately three minutes, both chambers then pull a vacuum for about seven minutes the upper chamber is released to atmosphere for a total cycle of about 10 minutes. Aluminum sheets (not shown) are preferably used as carrier sheets to carry the laminate  38  into and out of the laminator. A gritted surface such as sandpaper (not shown), is preferably provided on one of the carrier sheets to provide a textured surface to the first laminate sheet  44 . Alternatively, the aluminum of the carrier sheets or the platen of the laminator themselves could be textured to provide the textured surface to the first laminate sheet  44 . The back sheet  52  is then attached to the second laminate layer  46 , preferably using the third adhesive layer  54 . While a preferred series of layers for the photovoltaic laminate  38  has been described above, other arrangements of layers and other materials for the individual layers could be used to achieve the same result of securing photovoltaic cells  16  to the tile base  18 . 
         [0032]    Referring to  FIG. 4 , once the photovoltaic laminate  38  has been assembled, the photovoltaic laminate  38  is inserted into a mold  58 . The laminate  38  is preferably preheated to a predetermined temperature to prevent the photovoltaic laminate  38  from being subjected to two different heats, one on each side of the photovoltaic laminate  38 , that could cause the photovoltaic laminate  38  to warp during cooling. Preheating the laminate  38  allows the laminate  38  and tile bale  18  to cool and shrink generally at a similar rate and amount. Once in place in the mold  58 , the photovoltaic laminate  38  is preferably held toward a first side  58   a  of the mold  58  by a vacuum  58   c  or other means. Because the photovoltaic laminate  38  is flexible, the photovoltaic laminate  38  conforms to the shape  58   d  of the mold  58  (the generally shape  58   d  of the mold  58  is shown in phantom). A rigid contact support  62  is preferably inserted over the contact tab  56  during the molding process as well forming a male connector  64  such that the contact support  62  is positioned between the contact tab  56  and the first side  58   a  of the mold  58  during molding. However, the contact support  62  may be integrally formed with the tile base  18 . When cooled, the contact support  62  adds stiffness to the contact tab  56  extending from the top edge  18   c  of the tile base  18 . A molten polymeric material is then injected into the mold  58  through an injection port  60  on a second side  58   b  of the mold  58  to form the tile base  18  underneath the laminate  38 . The back sheet  52  protects the photovoltaic layer  42  and the second laminate sheet  46  from being damaged proximate the injection port  60  where the injected material for the tile base  18  is at its highest temperature. An outwardly extending flange  66  ( FIG. 2 ), is preferably molded around a portion the contact support  62  and the contact tab  56  proximate the top edge  18   c  forming a rigid male connector  64 . The flange  66  preferably includes an elastomeric o-ring  66   a  that is assembled onto the flange  66  after the molding process (See  FIG. 13 ). Though it is preferred that the flange  66  be integrally molded with the tile base  18 , the flange  66  may be separately assembled or may be part of the contact support  62 . The photovoltaic roofing tile  12  is preferably molded in a generally vertical orientation to enable gravity to assist in maintaining the proper positioning of the photovoltaic laminate  38  and the contact support  62  during the molding process. Though it is preferred that the photovoltaic laminate  38  be fixed to the tile base  18  using the insert molding process described above, the photovoltaic laminate  38  may be mounted to the tile base  18  in any suitable manner such as using an adhesive or fasteners. Once the photovoltaic roofing tile  12  has sufficiently cooled, the photovoltaic roofing tile  12  is removed from the mold  58 . Once removed from the mold, it is preferred that the first and second terminal ends  40   a ,  40   b  are exposed on a bottom surface of the male connector  64  as a result of the molding process to form a rigid, integral male electrical plug or connector  64  right out of the mold  58  without the need for further steps or attachments. The first and second terminal ends  40   a ,  40   b  may be exposed through the laminate  38  in any direction on the male connector  64  so long as there is no need to perform additional steps once the photovoltaic roofing tile  12  is removed from the mold  58  such as removing material from the male connector  64  or attaching additional components. 
         [0033]    Referring to  FIG. 2 , though the photovoltaic laminate  38  is generally thin, it is preferred that the photovoltaic laminate  38  be generally flush with the remainder of the first side  18   a  of the tile base  18 . The photovoltaic laminate  38 , except for the contact tab  56 , is preferably spaced from the top edge  18   c  by a second tile overlap distance D 2 . During installation, a subsequent upper row of photovoltaic roofing tiles the previous lower row of photovoltaic roofing tiles  12  by the overlap distance D 2  preferably such that only the photovoltaic laminate  38  is exposed and any portion of the first side surface  18   a  not covered by the photovoltaic laminate  38  is covered by an adjacent overlying photovoltaic roofing tile  12  or adjacent non-photovoltaic roofing tile  14 . Spacing the photovoltaic laminate  38  from the top edge  18   c  allows for the nail targets  24  and batten latches  28  to extend through the base tile  18  without damaging or otherwise impacting the photovoltaic laminate  38 . The photovoltaic laminate  38  preferably extends from the first lateral side  18   e  to the second lateral side  18   f  of the tile base with the photovoltaic layer  42  being spaced from the first lateral side  18   e  by the first overlap distance D 1 . However, the photovoltaic laminate  38  need not necessarily extend from the first lateral side  18   e  to the second lateral side  18   f  and may be cover any suitable amount of the first side surface  18   a  such as being spaced from the first lateral side  18   e  by the first overlap distance D 1  to prevent being contacted by an adjacent photovoltaic roofing tile  12 . 
         [0034]    Referring to  FIGS. 5 and 6 , the non-photovoltaic roofing tiles  14  are configured and manufactured in a similar manner as the photovoltaic roofing tiles  12  except that the non-photovoltaic roofing tiles  14  do not include the male connector  64  and the photovoltaic laminate  38  is replaced with a cover  68 . The components of the non-photovoltaic roofing tile  14  that are similar to photovoltaic roofing tile  12  have been labeled with similar numbering as the photovoltaic roofing tile  12  with the addition of a trailing prime symbol. The cover  68  is comprised of an upper layer  70 , a fourth adhesive layer  72  and a back sheet  52 ′. The upper layer  70  is preferably a glossy layer of weatherproof paint such as the type used on automobiles. However, any suitable material may be used so long as the upper layer  70  has a similar appearance as the photovoltaic laminate  38  to help create a visually consistent roof  20  where it is not readily discernable which roofing tiles  12 ,  14  are the photovoltaic roofing tiles  12  and which roofing tiles  12 ,  14  are the non-photovoltaic roofing tiles  14 . The cover  68  is preferably molded to the tile base  18 ′ in a similar manner as described above for the laminate  38  of the photovoltaic roofing tile  12 . 
         [0035]    Referring to  FIGS. 7-9 , photovoltaic roofing tiles  12  are electrically connected to each other through a plurality of corresponding female connectors  74  and battens  26 . The battens  26  are preferably custom made and replace the use of conventional battens (not shown). However, the battens  26  may alternatively be comprised of a cover (not shown) that extends over the conventional battens. The battens  26  are preferably molded of a polymeric material and are mounted to a batten sheet  76 . The batten sheet  76  is preferably a flexible sheeting material similar to conventional roofing underlayments  78  ( FIG. 9 ). The batten sheet  76  preferably includes nail markings (not shown) to indicate where the battens  26  and or photovoltaic roofing tiles  12  are to be installed. The batten sheet  76  may be used in place of the conventional underlayment  78  or the batten sheet  76  may be installed in addition to and on top of the conventional underlayment  78  (see  FIG. 9 ). The batten sheet  76 , battens  26  and female connectors  74  are preferably used only under the photovoltaic roofing tiles  12  while only conventional battens are used under the non-photovoltaic roofing tiles  14 . However, the batten sheet  76  and battens  26  may extend under or be used under the non-photovoltaic roofing tiles  14  as well. 
         [0036]    The batten sheet  76  is preferably installed with the battens  26  and female connectors  74  already attached prior to installation. Pre-installation of the battens  26  and the female connectors  74  facilitates simplified installation of the integrated solar roofing system  10  and allows for automated and precise assembly in a factory setting. However, the battens  26  and female connectors  74  may be assembled on the roof surface  20  as well. The female connectors  74  are preferably pre-installed on the respective batten  26  and the battens  26  are attached to the roof surface  20  or batten sheet  76  at the appropriate locations by the manufacturer or distributor. However, the female connectors  74  may be attached to the battens  26  during roof installation, with the spacing being measured or dictated by the location of the corresponding male connector  64 . If the batten sheet  76  is installed first without pre-connected battens  26 , the batten sheet  76  is installed in the same manner that the conventional underlayment  78  is installed except that the batten sheet  76  preferably includes nail markings for positioning of the battens  26 . Once the batten sheet  76  is installed in an area where the photovoltaic roofing tiles  12  are to be installed, the battens  26  are nailed or otherwise secured into place and the female connectors  74  are positioned on the battens  26  where it is projected that a male connector  64  will extend from the top of the photovoltaic roofing tiles  12 . The male connector  64  allows for mechanical and electrical connection of the photovoltaic cells  16  and the female connectors  74  such that adjacent photovoltaic roofing tiles  12  may be electrically connected to combine the resulting electrical energy. 
         [0037]    Referring to  FIG. 10 , each female connector  74  is preferably pivotably attached to the respective batten  26 . The battens  26  each include a C-shaped pivot extension  80  extending from the upper edge of the batten  26 . A nail extension  82  preferably extends from the lower edge of the batten  26  in the opposite direction from the pivot extension  80 . The nail extension  82  preferably has a smaller thickness than the remainder of the batten  26  and is preferably used for receiving nails (not shown) or other fasteners for securing the batten  26  to the roof surface  20 . The nail extensions  82  may include nail markings (not shown) to indicate where a nail or fastener should be inserted. The female connectors  74  preferably each include a pair of generally cylindrical pivot arms  84 . The pivot arms  84  extend laterally from the remainder of the female connector  74  and are pivotably disposed within the pivot extension  80 . The pivot arms  84  are preferably snap fit into the pivot extension  80  such that the female connector  74  may be easily installed and removed from the batten  26 . If the female connectors  74  and battens  26  are pre-installed or temporarily secured to the batten sheet  76 , the batten sheet  76  may be directly rolled, vertically upwardly rather than from left to right, onto the roof structure  20  with the battens  26  and female connectors  74  already in the appropriate positions (see  FIG. 9 ). The pivotal connection of the female connector  74  to the batten  26  not only allows for a slight tilt of the female connector  74  during installation as described further below but the pivotal connection of the female connectors  74  with respect to the battens  26  also allows for the female connectors  74  to be at least partially folded on top of the batten  26  such that the batten sheet  76  may be rolled up with the battens  26  and female connectors  74  already in place. Once the batten sheet  76  is unrolled, the female connectors  74  pivot to lay against the batten sheet  76  due to gravity or are manually flipped down onto the batten sheet  76  by the installer prior to installation of the photovoltaic roofing tiles  12 . 
         [0038]    Referring to  FIGS. 10-13 , each female connector  74  includes a pair of first and second contacts  90 ,  92  preferably in the form of two U-shaped clips that receive and tightly engage the distal end of the male connector  64  such that the first and second terminal ends  40   a ,  40   b  are in direct and positive electrical contact with the first and second contacts  90 ,  92  respectively. The first and second contacts  90 ,  92  may have any shape capable of allowing a good electrical connection between the first and second terminal ends  40   a ,  40   b  and the first and second contacts  90 ,  92  and need not extend over the contact support  62 . A first electrical wire  94  is connected to the first contact  90  and a second electrical wire  96  is connected to the second contact  92 . The first and second electrical wires  94 ,  96  each include an insulating cover  94   a ,  96   a  respectively. 
         [0039]    Referring to  FIGS. 11 and 13 , the first and second electrical wires  94 ,  96  are preferably contained, or at least partially contained, within the battens  26 . A wire groove  98  extending into and along the pivot extension  80  is preferably provided for example for receiving and retaining the first and second electrical wires  94 ,  96  as they runs from one female connector  74  to the next female connector  74  along the batten  26 . Though it is preferred that the first and second wires  94 ,  96  be contained within the pivot extension  80 , the first and second electrical wires may be at least partially contained within the batten  26 , within the batten sheet  76  or not restrained at all. The first and second electrical wires  94 ,  96  may also be integrally provided within the batten  26  and the contact between the pivot arms  84  or the like between the female connector  74  and the batten  26  could also establish an electrical connection with internal electrical wiring or electrically conductive elements (not shown). The first electrical wire  94  extends in one lateral direction along the batten  26  and the second electrical wire  96  extends in the opposite lateral direction along the batten  26  such that there is an electrical input and an electrical output to the female connector  74 . The first and second electrical wires  94 ,  96  may extend to an adjacent or other photovoltaic roofing tile  12 , off of the roof surface  20 , or to any other electrical component. 
         [0040]    A bypass diode  100  preferably extends between the first and second contacts  90 ,  92  such that the first and second contacts  90 ,  92  and the circuitry  40  in the photovoltaic layer  42  may be electrically bypassed allowing electricity to run from the first electrical wire  94  to the second electrical wire  96  without interruption in the event that the photovoltaic roofing tile  12  fails or the connection between the female connector  74  and the male connector  64  is interrupted. A first crimp sleeve  102  preferably secures the first electrical wire  94  to the first contact  90  and a second crimp sleeve  104  preferably secures the second electrical wire  96  to the second contact  92 . The first and second crimp sleeves  102 ,  104  also preferably hold the bypass diode  100  in connection with the first and second electrical wires  94 ,  96 . 
         [0041]    The female connector  74  is preferably comprised of a back cover  74   a  and receiving window  74   b . The receiving window  74   b  is at least partially open toward the batten  26  for receiving the male connector  64  from a photovoltaic roofing tile  12 , preferably allowing the only access to the first and second contacts  90 ,  92 . The receiving window  74   b  preferably includes sealing ribs  106  extending toward the center of the receiving window  74   b  and slanted back toward the back cover  74   a  ( FIG. 13 ). The back cover  74   a  and the receiving window  74   b  are preferably held together with screws  74   c  extending through the back cover  74   a  ( FIG. 11 ) and into screw supports  74   d  in the receiving window  74   b  ( FIG. 12 ). The back cover  74   a  and receiving window  74   b  are preferably sealed together with an elastomeric gasket  108 . Though the two piece female connector  74  is preferred for assembly purposes, the female connector  74  may be comprised of one or more sections and is not limited to having a separate back cover  74   a  and receiving window  74   b.    
         [0042]    Referring to  FIG. 13 , the o-ring  66   a  on the flange  66  extends slightly further than the width and length of the opening of the receiving window  74   b . When the male connector  64  is inserted into the female connector  74 , the o-ring  66   a  is compressed and the flange  66  preferably engages the ribs  106  to seal the male connector  64  to the female connector  74  and prevent over insertion of the male connector  64 . The flange  66  may also snap fit or be otherwise temporarily retained within the receiving window  74   b . When the flange  66  is inserted into the receiving window  74   b , the exposed first and second terminal ends  40   a ,  40   b  contact lower arms  90   a ,  92   a  of the first and second contacts  90 ,  92 , respectively ( FIG. 13 ). The contact tab  56  and the contact support  62  spread apart the first and second contacts  90 ,  92  to spring bias the first and second contacts  90 ,  92  into good electrical contact with the first and second terminal ends  40   a ,  40   b  respectively. The receiving window  74   b  may include a pierceable covering (not shown) or alternatively the ribs  106  may be held in compressive contact to seal the female connector  74  during assembly to further prevent a human finger (not shown) from touching the first and second contacts  90 ,  92  but may separate with sufficient force caused by the insertion of the male connector  64 . 
         [0043]    The female connectors  74  along a batten  26  are electrically connected by the first and second electrical wires  94 ,  96 . The battens  26  may be configured either in parallel or series. For example, when the photovoltaic roofing tiles  12  are arranged in series, the first and second electrical wires  94 ,  96  runs from a female connector  74  to the next adjacent female connector  74  along one row from left to right such that the electrical wires  94 ,  96  do not cross ( FIGS. 11 and 12 ). In the next row, the ends of the first and second electrical wires  94 ,  96  from right to left cross (not shown) such that first and second wires  94 ,  96  alternates between the inner most and outmost entry point of the adjacent female connector  74 . Such a configuration allows for a series connection with the same photovoltaic roofing tiles  12  used throughout and prevents the installer from confusing photovoltaic roofing tiles  12  that have reversed positive and negative terminal ends  40   a ,  40   b . Alternatively, each photovoltaic roofing tile  12 , or more likely, each row of photovoltaic roofing tiles  12 , may be connected in parallel. The first and second electrical wires  94 ,  96  may also extend to a different batten  26  or off of the roof surface  20 . Regardless of the preferred configuration, the electrical schematic may be determined and assembled in a factory setting, allowing the installer to simply install the photovoltaic roofing tiles  12  similarly to the non-photovoltaic roofing tiles  14  without worrying about the electrical schematic and arrangement of the photovoltaic roofing tiles  12  other than to connect the male connector  64  of each of the photovoltaic roofing tiles  12  to the corresponding female connector  74 . 
         [0044]    Referring to  FIGS. 1 ,  14  and  15 , the photovoltaic roofing tiles  12  and the non-photovoltaic roofing tiles  14  are preferably installed in a conventional overlapping fashion. For example, a first row of tiles  110  is installed from left to right overlapping the previous photovoltaic or non-photovoltaic tile  12 ,  14  by a first overlap distance D 1  ( FIG. 2 ) and then similarly installing a second row of tiles  112  from left to right that overlap the first row of tiles  110  by the second overlap distance D 2  ( FIG. 2 ). The photovoltaic roofing tiles  12  and the non-photovoltaic roofing tiles  14  are preferably installed in a similar manner to one another in that the photovoltaic roofing tiles  12  and the non-photovoltaic roofing tiles  14  are slid upwardly on a plane spaced from and generally parallel to the roof surface  20  such that each photovoltaic and non-photovoltaic roofing tile  14  is slid across the batten  26  (see  FIGS. 14 and 15 ). The photovoltaic roofing tiles  12  preferably differ in installation in only that the male connector  64  must be aligned with the corresponding female connector  74 . The horizontal receiving port  74   b  of the female connector  74  allows the male connector  64  to be inserted within the female connector  74  without vertical displacement (perpendicular to the roof surface  20 ) of the photovoltaic roofing tile  12 . As the photovoltaic roofing tile  12  is slid across the batten  26  a distal end  28   b  of the batten latch  28  contacts the front top edge of the batten  26  and deflects the batten latch  28  upwardly into the batten recess  28   c  such that the batten latch  28  is deflected out of the way and does not prohibit or limit the photovoltaic roofing tile  12  from being slid across the batten  26 . Once the distal end  28   b  of the batten latch  28  passes the upper edge of the batten  26 , the batten latch  28  returns to its initial position under its own bias such that the distal end  28   b  engages or latches on to the upper rear edge of the batten  26 . The batten latch  28  engages with the batten  26  such that the photovoltaic roofing tile  12  is temporarily held in place and prevents the photovoltaic roofing tile  12  from sliding off of the batten  26  during installation. Simultaneously with the engagement of the batten latch  28  with the batten  26 , the male connector  64  slides into the female connector  74  such that an electrical connection is established. Because the mechanical connection to the female connector  74  may not be sufficient to hold the photovoltaic tile  12  in place, the batten latch  28  ensures that the photovoltaic roofing tile  12  remains in place until a nail  114  ( FIG. 15 ) or other fastener more is driven through the recessed nail targets  24  to more permanently secure the photovoltaic roofing tile  12  to the batten  26  and/or roof surface  20 . 
         [0045]    The horizontal installation of the photovoltaic roofing tile  12  also allows for easier removal and replacement of a defective photovoltaic roofing tile  12  without disturbing adjacent tiles  12 ,  14 . During removal or replacement of the photovoltaic roofing tile  12 , the nail  114  is removed and the batten latch  28  is either disengaged by the use of a tool (not shown) or may be broken off to allow the photovoltaic roofing tile  12  to be removed in a generally planar fashion as similar to insertion. A replacement photovoltaic roofing tile  12  is then installed similarly to the initial installation such that the photovoltaic roofing tile  12  is slid in a plane generally parallel to the roof surface  20  and the male connector  64  is inserted into the female connector  74 . 
         [0046]    Installation of the photovoltaic tiles  12  concludes by dropping two leads, positive and negative (not shown), that extend from the batten sheet  76  or the upward most solar roofing batten  26  connected to the electrical wires with “quick-connect” terminals (not shown) into the roof ridge line or through a hole drilled through the roof surface  20 . The leads allow an electrician to connect one batten sheet  76  to another batten sheet  76 . 
         [0047]    It will be appreciated by those skilled in the art that changes could be made to the embodiment described above without departing from the broad inventive concepts thereof. It is understood, therefore, that this invention is not limited to the particular embodiment disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as defined by the appended claims. 
         [0048]    Further, to the extent that the assembly methods do not rely on the particular order of steps set forth herein, the particular order of the steps in the steps set forth in the preferred methods should not be construed as limitation on the claims. The claims directed to the method of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the steps may be varied and still remain within the spirit and scope of the present invention.