Busses for bifacial photovoltaic cells

Abstract

PV module composed of individual PV cells oriented and electrically connected according to a methodology that is viable for at least i) bifacial cells with substantially equal solar-energy conversion efficiency achievable on each side of each cell, and ii) PV modules with low operating current. Embodiments of the invention facilitate the use of different busing technologies to reduce cost and complexity of the resulting PV module while increasing the electrical energy harvested by the PV module.

What is claimed is: 
     
         1 . A solar module comprising:
 a first bifacial solar cell having a first front active side and a first back active side, wherein the first front and back active sides have substantially equal solar conversion efficiencies, the first front active side having a first electrical polarity, the first back active side having a second electrical polarity that is opposite to the first electrical polarity;   a second bifacial solar cell having a second front active side and a second back active side, wherein the second front and back active sides have substantially equal solar conversion efficiencies, the second front active side having the second electrical polarity and the second back active side having the first electrical polarity,   the first and second bifacial solar cells oriented in series such that the first front active side is facing in substantially the same direction as the second front active side,   
       and
 a bus bar electrically coupling the first front active side to second front active side. 
 
     
     
         2 . A solar module according to  claim 1 , wherein the first and second bifacial solar cells are arranged adjacent to one other, and the first front active side is substantially coplanar with the second front active side. 
     
     
         3 . A solar module according to  claim 1 , further comprising
 a third bifacial solar cell having a third front active side and a third back active side, wherein the second front and back active sides have substantially equal solar conversion efficiencies,   the third front active side having the first electrical polarity, the third back active side having the second electrical polarity,   the third bifacial solar cell oriented such that the third front active side faces substantially the same direction as the first front active side;   and   a bus bar electrically coupling the second back active side to the third back active side.   
     
     
         4 . A solar module according to  claim 1 , further comprising an encapsulant layer disposed on the first front active side and the second front active side such as to cover the bus bar. 
     
     
         5 . A method for fabrication of a photovoltaic (PV) module, comprising:
 separating a PV cell having an original size into a plurality of PV sub-cells, each sub-cell having a size smaller than the original size;   electrically coupling the sub-cells in series such that a first side of the first sub-cell having a first electrical polarity is electrically connected to a first side of the second sub-cell having a second electrical polarity, the first side of the first sub-cell and the first side of the second sub-cell oriented to face substantially the same direction.   
     
     
         6 . A method according to  claim 5 , wherein the first side of the firs sub-cell is positioned to be substantially co-planar with the first side of the second sub-cell. 
     
     
         7 . A method according to  claim 5 , wherein said electrically coupling includes
 depositing a conformable electrically conductive material on a first surface of an optically-transparent encapsulation layer; and   covering the first and second sub-cells with said optically-transparent encapsulation layer such that the first surface of the optically transparent encapsulation layer carrying the conformable electrically-conductive material faces the first side of the first sub-cell and the first side of the second sub-cell.   
     
     
         8 . A method according to  claim 7 , wherein said depositing includes depositing at least one of conductive epoxy, wire mesh, or charge collection tape. 
     
     
         9 . A method according to  claim 5 , further comprising disposing a holographic element in optical communication with at least one of the first and second sub-cells between the optically-transparent encapsulation layer and a surface of the at least one of the first and second sub-cells.