On Methodologies for Assessment of Long‐Term Potential‐Induced Degradation of Double‐Glass Tunnel Oxide Passivated Contact Photovoltaic Modules

Polarization‐type potential‐induced degradation (PID‐p) has become a risk for tunnel oxide passivated contact (TOPCon) solar cell modules. For the sake of intimating the long‐term PID‐p degradation of the modules under outdoor illumination, this study investigates the impact of different types and timing of illumination on the PID‐p on the double‐sided EVA encapsulated TOPCon modules: 1) multiple cycles of a PID test in the dark followed by a 2 kWh UV recovery; 2) PID tests under 170 W/m 2 UV illumination; and 3) PID tests under 800 W/m 2 simulated steady‐state solar illumination. We find that all three testing methods lead to less power degradation than that in the dark after 96 h so that TOPCon photovoltaic modules will not suffer from severe PID‐p risk in short term when running outdoors. After 672 h, the module subjected to PID tests under 800 W/m 2 simulated steady‐state solar illumination shows the lowest degradation of −3.18%. This method more closely resembles the long‐term outdoor operating conditions, where the module generating voltage under illumination forms a ground potential. Moreover, excessive UV irradiation in the testing method may exacerbate the UV‐induced degradation issue and accelerate the aging of the encapsulant.