Hotspot risk assessment model for TOPCon solar cells based on reverse-biased EL imaging

Abstract

Temperature management is of great significance for ensuring the stability and reliability of photovoltaic (PV) modules. The “hotspot” phenomenon, a localized temperature rise in solar cells due to the current mismatch, pose a significant operational risk. This study introduces a rapid hotspot risk assessment method for TOPCon cells based on reverse-biased electroluminescence (EL) imaging. The proposed model predicts both the location and severity of heating under reverse bias, outputing an evaluation parameter that serves as screening criteria to identify and eliminate high-risk cells. Experimental results indicate that PV modules built with screened cells exhibit a 5–13 °C reduction in hotspot temperature, effectively controlling the hotspot temperature below 171 °C. Furthermore, a 40-day outdoor test confirms that this approach reduces power generation loss by approximately 1 %. As this method requires only EL images as input, it offers excellent compatibility for seamless integration into industrial production lines, enabling proactive hotspot risk mitigation in the manufacture process of PV modules.