Influence of Interconnection Concepts for IBC Solar Cell Performance by Simulation

This work describes interdigitated back-contact cells with a number of different rear side geometries, for different interconnection concepts and module integration, by means of numerical simulations. We show that a simple interconnection concept can be realized with copper wires as bus features and interrupted metal electrodes to avoid shunting, without severe losses compared to multilayer metallization concepts. Using Quokka3, which due to enhanced speed allows for very large simulation sizes, this enables principal investigations undescribed in previous literature. We use this to investigate the disconnection of a single (or multiple) solder joint(s) in terms of device performance, in the case of interrupted metal electrodes. Our findings show that disconnected emitter electrodes cause higher power losses than disconnected BSF electrodes (∼x4), both following a linear relationship. Nevertheless, when multiple of such defects are aligned, the losses are increasing much stronger. We accordingly derive the need to balance design choices such as BSF and emitter width in an industrial implementation, with an empirically derived disconnection probability.