scope:

This part of IEC 63202 describes procedures for measuring the light and elevated temperature induced degradation (LETID) of crystalline silicon photovoltaic (PV) cells in simulated sunlight. The requirements for measuring initial light induced degradation (LID) of crystalline silicon PV cells are covered by IEC 63202-1, where LID degradation risk of PV cells under moderate temperature and initial durations within termination criteria of 20 kWh·m-2 are evaluated. Energy yield of PV modules is significantly affected by the inherent LETID performance of the PV cells, which are used in it. This LETID performance includes LID and other degradation mechanisms. The procedures described in this document are to evaluate the degradation behaviour of PV cells under elevated temperature and longer duration of light irradiation. The degradation rate, maximum degradation ratio and possible regeneration are determined by comparing the cell maximum power, Pmax, at Standard Test Conditions (STC) during the light irradiation process with respect to the initial Pmax. A Pmax degradation profile with respect to cumulative irradiation is presented, which helps cell manufacturer to judge whether the cells are prone to LETID before assembled into modules.