Postmetallization 'Passivated Edge Technology' for Separated Silicon Solar Cells

Abstract

This article introduces a postmetallization 'passivated edge technology' (PET) treatment for separated silicon solar cells consisting of aluminum oxide deposition with subsequent annealing. We present our work on bifacial shingle solar cells that are based on the passivated emitter and rear cell concept. To separate the shingle devices after metallization and firing, we use either a conventional laser scribing mechanical cleaving (LSMC) process or a thermal laser separation (TLS) process. Both separation processes show similar pseudo fill factor (pFF) drops of-1.2%abs from the host wafer to the separated state. The pFF of the TLS-separated cells increases by up to +0.7%abs from the as-separated state after PET treatment due to edge passivation, while the pFF of LSMC-separated cells increases by up to +0.3%abs. On cell level, the combination of TLS and PET allows for a designated area output power density of pout = 23.5 mW/cm taking into account an additional 10% rear side irradiance.