C.2 Analysis Phase
Before redesigning the solar cells, it is necessary to obtain a better understanding of PV technology. Therefore, PV modules are analyzed because solar cells are generally used in a PV module. Next to this, the PV market and target group are explored. The derived information from this analysis is used to determine the demands and wishes of the new solar cell and PV module.
The characteristics and production of solar cells provide information about the limitations and possibilities in cell design. An important aspect is the production of the cell, because the metal contact pattern is applied by screen printing and a redesigned contact pattern must be printable.
The screen-printing process of a solar cell is similar to that of textiles. The machine squeezes silver paste through a patterned screening mesh onto the cell surface. After the paste is applied, the paste is dried at low temperature and then fired at a higher temperature. This step drives off the remaining organics and allows the silver regions to combine.
The advantages of screen printing are in its simplicity and cost-effectiveness. The disadvantages of screen printing are the relative large line width, the high contact resistance, and the low aspect ratio of the metal lines (broad and flat), which results in large shadowing losses.
The limitations and possibilities of screen printing lead to boundaries in metal line widths and heights. Beside these boundaries, the shape of the lines must be taken into ...