Novel framework for Metal Wrap Through solar cell top contact design optimization

The Metal Wrap Through (MWT) cell, which replace the metal busbars with several holes bored through the silicon wafer, is a high efficiency cell which had caught the attention of cell makers. But the contact design methodology for conventional cell is inadequate when used for MWT. This paper reports a procedure for MWT power loss calculation and drilled hole spacing optimization. First, the concept for choosing unit cell is reported, followed by the development of calculation models for the MWT emitter, finger resistance and shadowing loss. An example is demonstrated using this simulation procedure to obtain the suggested hole count and spacing.