ABSTRACT:

In this paper, an interconnection method for the module integration of silicon solar cells by laser microwelding of the Al-metalized rear side of the solar cell to a metalized substrate is introduced. This laser microwelding process forms a direct mechanical and electrical connection between two Al-layers without the need for any soldering, conductive adhesives, or Ag-pastes. With a tensile tester, we measure tear-off stresses of up to 303 kPa for our laser weld spots. Furthermore, carrier lifetime measurements show that no defects are induced into the Si-crystal by the laser process over a wide range of laser pulse energies and number of laser pulses. In order to demonstrate the applicability of this laser-based interconnection method, we present a proof-of-concept module consisting of five n-type back-junction back-contact solar cells with a conversion efficiency of 20.0%.