MOISTURE INGRESS RESISTANT PHOTOVOLTAIC MODULE
One embodiment of the present invention provides a photovoltaic (PV) module. The PV module includes a front-side glass cover facing sunlight, a plurality of interconnected PV cells situated below the glass cover, a plurality of bussing wires electrically coupled to the PV cells, and a back-sheet situated below the PV cells. The back-sheet comprises a metal layer sandwiched between a top and a bottom insulation layers. The back-sheet comprises a cut slot to facilitate the bussing wires to thread through the cut slot to reach a junction box situated below the back-sheet. The PV module further comprises one or more insulation layers inserted between the bussing wires and sidewalls of the cut slot in the back-sheet. The insulation layers are configured to insulate the bussing wires to the metal layer in the back-sheet.
1 . A photovoltaic (PV) module, comprising:
a front-side glass cover facing sunlight;
a plurality of interconnected PV cells situated below the glass cover;
a plurality of bussing wires electrically coupled to the PV cells;
a back-sheet situated below the PV cells, wherein the back-sheet comprises a metal layer sandwiched between a top insulation layer and a bottom insulation layer, wherein the back-sheet comprises a cut slot to facilitate the bussing wires to thread through the cut slot to reach a junction box situated below the back-sheet; and
one or more insulation layers inserted between the bussing wires and sidewalls of the cut slot in the back-sheet, wherein the insulation layers are configured to insulate the bussing wires to the metal layer in the back-sheet.
2 . The PV module of claim 1 , wherein the insulation layers in the back-sheet include one or more of: polyethylene terephthalate (PET), Fluoropolymer, polyvinyl fluoride (PVF), and polyamide; and wherein the metal layer in the back-sheet comprises Al.
3 . The PV module of claim 2 , wherein the back-sheet includes one or more of:
a dyMat APYE® back-sheet made by Coveme;
a Protekt® back-sheet made by Madico, Inc.; and
an Al-based back-sheet made by Isovolta Group or Dunmore Corporation.
4 . The solar cell of claim 1 , wherein the one or more insulation layers include at least one of:
dielectric tape;
a tube made of dielectric materials;
a non-metal partial back-sheet; and
a partial back-sheet with a metal interlayer.
5 . The PV module of claim 4 , wherein the dielectric tape includes Kapton® tape.
6 . The PV module of claim 4 , wherein the tube includes at least one of:
a polyethylene terephthalate (PET) tube; and
a polyvinyl fluoride (PVF) tube.
7 . The PV module of claim 4 , wherein the non-metal partial back-sheet includes a Protekt® back-sheet or a Tedlar® back-sheet.
8 . The PV module of claim 1 , further comprising an additional partial back-sheet situated between the PV cells and bussing wires at a location where the bussing wires thread through the cut slot, wherein the additional partial back-sheet includes a metal interlayer situated between a top insulation layer and a bottom insulation layer, and wherein the additional partial back-sheet is configured to:
insulate the bussing wires to a backside of the solar cells; and
block potential moisture ingress from the cut slot in the back-sheet.
9 . The PV module of claim 8 , wherein the additional partial back-sheet includes an Al interlayer.
10 . The PV module of claim 1 , wherein the PV cells include at least one double-sided tunneling junction solar cell.
11 . The PV module of claim 1 , wherein the PV cells and the bussing wires are encapsulated between the front-side glass cover and the back-sheet during a lamination process, forming a laminated structure.
12 . The PV module of claim 11 , wherein encapsulating the PV cells and the bussing wires involves using a low moisture vapor transmission rate (MVTR) encapsulant that comprises one or more of: polyolefin and ionomer.
13 . The PV module of claim 11 , further comprising a metal frame configured to hold the laminated structure.
14 . The PV module of claim 13 , wherein the metal frame is sufficiently large to ensure a predetermined minimum distance is maintained between corners and edges of the laminated structure and the metal frame, thereby facilitating application of insulation materials with sufficient thickness.
15 . The PV module of claim 13 , wherein corners of the laminated structure are wrapped with one or more layers of dielectric tape.
16 . The PV module of claim 1 , wherein the PV cells include one or more of:
a transparent conducting oxide (TCO) layer acting as an electrode; and
an anti-reflecting coating (ARC) layer.
17 . A method for fabricating a PV module, comprising:
obtaining a front-side glass cover;
obtaining a plurality of interconnected PV cells;
coupling the PV cells to a plurality of bussing wires;
obtaining a back-sheet, wherein the back-sheet comprises a metal layer sandwiched between a top insulation layer and a bottom insulation layer;
placing the PV cells and the bussing wires between the front-side glass cover and the back-sheet;
cutting a slot in the back-sheet;
applying one or more insulation layers around the bussing wires; and
threading the bussing wires through the cut slot in the back-sheet to reach a junction box situated below the back-sheet, wherein the applied one or more insulation layers are situated between the bussing wires and sidewalls of the cut slot in the back-sheet to insulate the bussing wires to the metal layer in the back-sheet.
18 . The method of claim 17 , wherein the insulation layers in the back-sheet include one or more of: polyethylene terephthalate (PET), Fluoropolymer, polyvinyl fluoride (PVF), and polyamide; and wherein the metal layer in the back-sheet comprises Al.
19 . The method of claim 17 , wherein the back-sheet includes one or more of:
a dyMat APYE® back-sheet made by Coveme;
a Protekt® back-sheet made by Madico, Inc.; and
an Al-based back-sheet made by Isovolta Group or Dunmore Corporation.
20 . The method of claim 17 , wherein the one or more insulation layers include at least one of:
dielectric tape;
a tube made of dielectric materials;
a non-metal partial back-sheet; and
a partial back-sheet with a metal interlayer.
21 . The method of claim 20 , wherein the dielectric tape includes Kapton® tape.
22 . The method of claim 20 , wherein the tube includes at least one of:
a polyethylene terephthalate (PET) tube; and
a polyvinyl fluoride (PVF) tube.
23 . The method of claim 20 , wherein the non-metal partial back-sheet includes a Protekt® back-sheet or a Tedlar® back-sheet.
24 . The method of claim 17 , further comprising inserting an additional partial back-sheet situated between the PV cells and bussing wires at a location where the bussing wires thread through the cut slot, wherein the additional partial back-sheet includes an Al interlayer situated between a top insulation layer and a bottom insulation layer, and wherein the additional partial back-sheet is configured to:
insulate the bussing wires to a backside of the solar cells; and
block potential moisture ingress from the cut slot in the back-sheet.
25 . The method of claim 17 , wherein the PV cells include at least one double-sided tunneling junction solar cell.
26 . The method of claim 17 , further comprising performing a lamination process to encapsulate the PV cells and the bussing wires between the front-side glass cover and the back-sheet, thereby forming a laminated structure.
27 . The method of claim 26 , wherein the lamination process involves using a low moisture vapor transmission rate (MVTR) encapsulant that comprises one or more of: polyolefin and ionomer.
28 . The method of claim 26 , further comprising placing the laminated structure in a metal frame.
29 . The method of claim 28 , wherein the metal frame is sufficiently large to ensure a predetermined minimum distance is maintained between corners and edges of the laminated structure and the metal frame, thereby facilitating application of insulation materials with sufficient thickness.
30 . The method of claim 28 , further comprising wrapping corners of the laminated structure with one or more layers of dielectric tape.
31 . The method of claim 17 , wherein the PV cells include one or more of:
a transparent conducting oxide (TCO) layer acting as an electrode; and
an anti-reflecting coating (ARC) layer.