Patent Publication Number: US-2020295208-A1

Title: Apparatus and method for solar panel

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to solar panels/modules for generating electrical energy, and more particularly to photovoltaic panels/modules with no frames. 
     2. Description of the Related Art 
     Conventional photovoltaic modules for generating electrical power for residences and businesses are often flat and are placed on a portion of a roof that is exposed to the sun. Historically, such modules were placed on structures erected on the roof to support and protect the modules. More recently, photovoltaic modules have become available that can be mounted directly on a flat or tilted roof. See, for example, U.S. Pat. Nos. 7,531,740, and 7,557,291 to Flaherty, et al., the entire contents of which are incorporated herein by reference. These patents disclose such photovoltaic modules for roof-top installation. 
     A problem with above mentioned direct roof top attached crystalline silicon photovoltaic cell based solar modules is need for flexible frame around module peripheral, which could accumulate water or debris that could interfere with the module performance by blocking sun irradiation. U.S. Pat. No. 9,673,344 to Davey et al. addressed this issue by eliminating said flexible frame and adding a butylene sealant around module peripheral. However incorporating of said butylene sealant increase modules&#39; material cost and build cost, as additional tool is needed for manufacturing of the modules on existing automated Si-wafer based module production line. Thus improved module design and construction method are needed for lowering module cost. 
     SUMMARY OF THE INVENTION 
     The photovoltaic module described herein and illustrated in the attached drawings enables electricity-generating solar modules to be manufactured quickly. 
     In accordance with one aspect according to the present invention, a photovoltaic module has an upper transparent protective layer, and a photovoltaic layer positioned beneath the upper transparent protective layer. The photovoltaic layer has a plurality of electrically interconnected photovoltaic cells disposed in an array. A semi-rigid substrate layer is positioned beneath the photovoltaic layer. The upper transparent protective layer has a first surface facing the photovoltaic layer. A second surface of the upper protective layer, opposite to the first surface, is facing away from the photovoltaic layer. The semi-rigid substrate has a first surface facing the photovoltaic layer. A second surface of the rigid substrate layer, opposite to the first surface, is facing away from the photovoltaic layer. The said upper transparent protective layer has a first in-plane dimension wider than said first in-plane dimension of the semi-rigid substrate by at least 2 mm. The said upper transparent protective layer has a second in-plane dimension wider than the 2 nd  in-plane dimension of the semi-rigid substrate by at least 2 mm. The said upper transparent layer is wrapped around all edges of said semi-rigid substrate layer. The wrapped upper protective layer is beneath the semi-rigid substrate layer. The first surface of the wrapped upper protective layer is facing the second surface of the semi-rigid substrate layer. 
     In accordance with another aspect of the present invention, a photovoltaic module has an upper transparent layer, and a photovoltaic layer positioned beneath the upper transparent layer. The photovoltaic layer includes a plurality of electrically interconnected photovoltaic cells disposed in a two-dimensional array and an electrical junction box on the same side of the module as the array of cells. A first layer of heat-activated transparent adhesive is interposed between the upper transparent layer and the photovoltaic layer to adhere the photovoltaic layer to the upper transparent layer. A semi-rigid layer is positioned beneath the photovoltaic layer. A second layer of heat-activated transparent adhesive is interposed between the photovoltaic layer and the semi-rigid layer to adhere the photovoltaic layer to the semi-rigid layer. The upper protective layer is disposed on top and about a periphery of the module, beneath said semi-rigid substrate layer, and beside said photovoltaic layer. 
     In accordance with a further aspect of the present invention, a method of making a photovoltaic module includes: (i) disposing a photovoltaic layer on an upper protective layer, the protective layer being wider and longer than the photovoltaic layer; (ii) disposing a semi-rigid substrate layer on the photovoltaic layer, the semi-rigid substrate layer being wider and longer than the photovoltaic layer, and narrower and shorter than the upper protective layer; (iii) the upper protective layer is folded around the photovoltaic layer and the semi-rigid and wrapped around peripheral of the semi-rigid substrate; and (iv) the folded part of upper protective layer is fixed on the semi-rigid substrate with suitable means forming a protective layer over the photovoltaic layer to prevent water and moisture ingress. Examples of suitable means can be, for example but not limited to, acrylic adhesives, butylene adhesives, etc. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Certain aspects in accordance with embodiments of the present invention are described below in connection with the accompanying drawing figures in which: 
         FIG. 1 a    illustrates a perspective view of a first embodiment of a laminated photovoltaic module according to the present invention with junction box showing conductors;  FIG. 1 b    illustrates another perspective view of the same embodiment of the model; 
         FIGS. 2 a  and 2 b    illustrate a top view and rear view of the photovoltaic module of  FIG. 1 , respectively; 
         FIG. 3  illustrates a cross-section view of the photovoltaic module of  FIGS. 1   a  and  1   b;    
         FIG. 4 , illustrates a close up rear view of a preferred embodiment of the photovoltaic module of  FIGS. 1 a  and 1 b    where front protective layer is fold and attach to the bottom surface of the substrate along module short edge. 
         FIG. 5  illustrates a close up rear view of a preferred embodiment of the photovoltaic module of  FIGS. 1 a  and 1 b   ; where front protective layer is further fold and attach to the bottom surface of the substrate along the module long edge secondly. 
         FIG. 6  illustrate a perspective view of a second embodiment of a laminated photovoltaic module according to the present invention with junction box showing conductors; 
         FIG. 7  illustrates the rear view of the photovoltaic module of  FIG. 1  with preferred peel- and stick (PAS) tape pattern. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is directed at frameless photovoltaic modules with no edge sealants. Edge sealant is a general description and should be understand as polymeric materials that either block moisture or impeding moisture ingress into photovoltaic layer and encapsulation layers from all sides of the photovoltaic modules except top and bottom sides. 
       FIGS. 1 a  and 1 b    illustrate perspective views of a preferred module configuration of this invention.  FIGS. 2 a  and 2 b    show a corresponding front view and rear view of the preferred module, respectively.  FIG. 3  shows detailed cross section view of the preferred module configuration. Laminated photovoltaic module  100  is sized as 990 mm×1383 mm with a thickness of 4 mm, and with either rounded corners or substantially right angle corners. Of course, the module  100  may be any suitable size and shape useful in different applications. 
     As shown in  FIG. 3 , the module  100  preferably has a transparent top protective layer  110  that faces upward and is exposed to the sun. A middle layer comprises a plurality of photovoltaic cells  122  electrically interconnected to form a photovoltaic array below the top layer. The middle layer preferably rests on a semi-rigid lower substrate  130 . The middle layer is preferably secured to the rigid lower layer by a lower adhesive layer  150 . The middle layer is preferably secured to the upper protective layer  110  by an upper adhesive layer  140 . The middle layer is thus encapsulated between the lower adhesive layer and the upper adhesive layer. 
     The upper protective layer  110  preferably provides weather protection as well as impact protection to the module  100 . The upper protective layer  110  advantageously comprises of a transparent flexible polymer material, such as, but not limited to fluorocarbon co-polymers Ethylene tetrafluoroethylene (ETFE) or polyvinylidene difluoride (PVDF) or polytetrafluoroethylene (PTFE), which is formed into a film layer of suitable thickness (e.g., approximately 0.025-0.2 mm). Or more preferably a film thickness of 0.05-0.15 mm. The upper film is preferably transparent and hydrophobic and with low water vapor transport rate (WVRT). Thus, the photovoltaic cells  122  in the middle layer are exposed to direct sunlight without being exposed to water and without being exposed to direct impact by feet, falling objects, and debris. Tempered glass having a suitable thickness may also be used as the upper protective layer  110 . 
     The semi-rigid lower layer substrate  130  preferably comprises a structural material, such as but not limited to glass or polymer or metal or fiber reinforced polymer or combinations of the above. For example, the fiber reinforced polymer (FRP) layer advantageously comprises a suitable thermoset or thermoplastic resin with stranded glass fiber reinforcement. Preferably the said FRP layer has a thickness of approximately 0.1 centimeter to 1 centimeter, and additionally, the said FRP has substantial flat lower and upper surfaces. The lower layer of FRP thus provides an advantageous combination of rigidity, light weight, very low permeability, electrical insulation, and flatness. 
     As shown in  FIG. 2 a   , the preferred embodiment provides that the photovoltaic cells  122  are arranged in an array of 6 columns×8 rolls cells (156.75 mm×156.75 mm in dimensions). Each two column cells are electrically interconnected in a series configuration. Three 2-columns of cells are further electrically interconnected in a series configuration to provide a suitable output voltage for flat roof and sloped roof application. Photovoltaic cell array  122  is shorter than the semi-rigid substrate  130  to provide room for positioning an electrical enclosure, such as, but not limited to junction box  170  (having a first weather-resistant electrical conductor  172  and a second weather-resistant electrical conductor  174 ) or module level power electronic enclosures. The photovoltaic cell array  122  preferably includes four or more module output conductors that are comprised of the start and the end of each 2-column cell strings. In this preferred embodiment, four output conductors  175 ,  176 ,  177 ,  178  extend from the top surface of the middle layer in the area outside the photovoltaic cell array  122 . Each of the module output conductors  175 ,  176 ,  177 ,  178  is preferably connected to one of three protective diodes within the electrical enclosure  170  in proper polarities and order after the photovoltaic module  100  is laminated, as discussed below. In an alternative embodiment, six array output conductors  175 ,  176   a ,  176   b ,  177   a ,  177   b ,  178  are connected to electrical junction box or MLPE enclosures which consist of up to 3 individual separated enclosures  170   a ,  170   b ,  170   c  with exposed flexible electrical conductors  170   d ,  170   e  electrically connecting the 3 enclosures as shown in  FIG. 6 . In yet another embodiment, the photovoltaic call array  122  is comprised of cut-cells, for example but not limited to ½ cut cells (156.75 mm×78.385 mm) or ⅓ cut cells (156.75 mm×52.25 mm). The cut cells are serial-parallel connected to the array output conductors  175 ,  176 ,  177 ,  178  for suitable module voltages. 
       FIG. 3  is a close-up cross section view of the  FIG. 1  embodiment, showing wraparound of the upper protective layer  110  at the edge of the module  100 . The upper layer  110  completely enclose all the sides  102 ,  103 ,  104 ,  105  of the module  100 , except bottom surface of semi-rigid substrate  130  and the upper layer  110  is being fixed on the bottom surface of the substrate  130  with suitable adhesives, as shown in  FIG. 2 b   . In this embodiment, the upper encapsulation layer  140  and lower encapsulation layer  150  are protected from direct contacts with water. Thus eliminates the need for using edge sealant materials in the frameless modules. Moisture ingress into the encapsulation layers  140  and  150  is now through the upper protection layer  110 , which is selected with low water vapor transport rate. Removal of edge sealants simplifies module layup process. Furthermore remove of the edge sealant make this frameless module fabrication process closer to standard framed Si cell modules and can be easily manufactured in standard module production factories. 
       FIG. 2 b    illustrates the upper protected layer  110  is affixed on the bottom surface  132  of the semi-rigid substrate  130  after wrapping around all the sides of the module  100  peripheral outer sides:  102 ,  103 ,  104 , and  105 . In this preferred embodiment, fixation is done after lamination of the module  100 . Fixation can be done by using, for example but not limited to, butylene adhesives, silicone, and acrylic either in tape format or liquid. A chosen adhesive  180  is placed on the surface  132  of the substrate  130  and forms a seamless profile along the surface  132  outer edges. The adhesive profile is placed from the module  100  peripheral outer edges of the surface  130  with a distance preferably 0-15 mm, or more favorably 5-8 mm. The adhesive profile is preferably with a width of 10-15 mm and a height of 0.3-1 mm. After adhesive&#39;s placement, the upper protective layer  110  can be pressed on the top of adhesive  180 . 
     A preferred embodiment of affixing the upper protective layer  110  on the semi-rigid substrate  130  is shown in  FIGS. 4 and 5 . As shown in  FIG. 4 , the upper layer  110  is folded along the substrate  130  short edges  102  and  104  first, and adhere to the substrate surface  132  by press on the adhesive profile along the short edges. Then the upper layer  110  is folded along the substrate  130  long edges and adhere to the substrate surface  132  by press on the adhesive profile along the long edges  103  and  105  as shown in  FIG. 5 . Alternatively, one can do this in the opposite sequence. 
     A preferred method of installation of the module  100  on a roof comprises applying a double stick suitable construction tape, such as but not limit to pressure sensitive butylene Peel-And-Stick (PAS) tape (commonly used in construction industry) to the bottom surface  132  of the semi-rigid substrate  130 , as shown in  FIG. 6 . PAS tape position is designed to further secure the portion of upper protective layer  110  fixed on the bottom surface  132 : A first PAS tape  200  is placed parallel to the first long edge  103  of the substrate  130  in a distance less than 20 mm from the said long edge and run from a first short edge  102  of the substrate  130  to the opposite short edge  104  continuously. A second PAS tape  210  is placed parallel to the second long edge  105  of the substrate  130  in a distance less than 20 mm from the said second long edge and run from the first short edge  102  of the substrate  130  to the opposite short edge  104  continuously. Preferably one more PAS tape  220  is placed between the said first and second PAS tape to provide increased security for the module  100  installation on roofs. Of course, more PAS tapes can be added for additional The PAS double-stick tapes are installed on to the module substrate  130  in the module factory after the upper layer  110  fixation on the substrate surface  132 . Thus the PAS tapes cover the fold corner portions of the upper protective layer  110  on the substrate surface  132  and protect the said folded upper layer  110 . One release layer is advantageously put on the surface of the installed PAS tape that is facing away from the module  100  for easy of module handling and transportation. The said release layer is removed when the module  100  is being installed so that the module can be adhered to the surface of an existing roof.