Advanced Module Technologies: Multi Bus Bars
Silicon solar cells are metallised with thin strips printed on the front and rear of a solar cell; these are called busbars and have the purpose of conducting the electric direct current (DC) power generated by the cell.
Older solar cells typically had two busbars; however, the industry has moved towards higher efficiencies and busbars have increased to three (or more) in most solar cells.
The increased number of busbars has several advantages:
first is the high potential for cost-saving due to a reduction in metal consumption for front-facing metallisation;
second, series resistance losses are reduced by employing thin wires instead of regular ribbon ; and third, optimising the width of the busbars leads to an additional rise in efficiency.
A higher number of busbars leads to higher module efficiencies because of reduced internal resistance losses; this is due to the lower distance between the busbars.
Finally, the multi-busbar design is highly beneficial for bifacial technology, especially for improving the facility for PERC cells of 90%.