Low-breakdown-voltage solar cells for shading-tolerant photovoltaic modules

Abstract

The integration of photovoltaic (PV) technology in urban environments poses new challenges for the design of PV modules. In particular, the poor shading tolerance of conventional PV modules strongly limits the energy performance of urban PV systems. In this work, we analyze how interdigitated back-contact solar cells with low-breakdown voltages can help improve the shading tolerance of PV modules. Through detailed simulations, we show that the breakdown voltage can be tuned without significantly degrading the efficiency of the solar cell. Simulation results indicate that, under partial shading conditions, cells with a 0.3-V breakdown voltage could boost by 20% the annual yield of conventional crystalline silicon PV modules with three bypass diodes. These findings are supported by a four-month-long monitoring campaign of PV modules with different breakdown characteristics, which shows a specific yield gain of about 4% in PV modules with six bypass diodes.