FRONT GRID DESIGN IN INDUSTRIAL SILICON SOLAR CELLS: MODELLING TO EVALUATE THE BEHAVIOUR OF THREE VS. TWO BUSES CELL PATTERNS

摘要

The increase in size of the silicon wafers that has been followed by the present industry makes raise the current that cells can provide. Thus, series resistance of the cells introduces a power loss that also tends to rise. Due to this, the series resistance in an industrial screen-printed silicon solar cell is known to be one of the most importance factors, which need to be optimized, especially through the modification of the front pattern design, in order to improve the conversion efficiency. The strong impact of the pattern design in the final efficiency makes it be a key point in the way of improving solar cell devices. This paper presents an analytical approach to evaluate the convenience of using a tree buses pattern in square cells of 156 mm size, instead of the two buses design typically used. The results of the modelling are presented comparing the final cell efficiency for the different patterns when both cover the same area of the cell. The same analytical model can also be used to predict the impact on cell performance of new emerging technologies for the front grid definition (as plating technologies). Results for the potential efficiencies that silicon solar cells could reach thanks to the improvements in pastes conductivity and metal-semiconductor contact resistance reduction are presented.