The use of four bus bars to a cell, as shown in figure 2, decreases the
distance between them. This proximity means electrons have less
far to travel to reach the ribbon, vastly improving the flow and the
reliability performance of the panel. This reduced distance lowers
the resistance in the cell, increasing current; in turn, this allows finger
width to be reduced, exposing more cell surface area to light and
generating more current, as well as keeping the fill factor high. The
reduction in cell resistance seen through adding a fourth bus bar
improves cell efficiency by over 0.2% per cell and adds 2 Wp per panel.