Identification of Recoverable and Non‐Recoverable Potential‐Induced Degradation‐Shunted Cells in Crystalline Silicon Photovoltaic Modules

ABSTRACT Potential‐induced degradation (PID) is a severe degradation mechanism in crystalline silicon (c‐Si) photovoltaic (PV) modules. In p‐type c‐Si PV modules, PID results in the formation of shunt paths on the front side of negatively biased cells relative to the grounded frame due to the diffusion of sodium ions (Na + ), a phenomenon known as PID shunting (PID‐s). Various methods for PID‐s recovery, which involve the outward diffusion of Na + , have been reported. However, whereas some cells show almost complete recovery, others exhibit no recovery at all. Conducting PID‐s recovery without knowing the recoverability of the cells is inefficient and wasteful; therefore, a method to identify recoverable and non‐recoverable cells prior to recovery is needed. In this work, a method using current‐resolved electroluminescence (EL) imaging is proposed to identify recoverable and non‐recoverable cells in a PV module by evaluating their PID‐s nature as ohmic or non‐ohmic, which depends on the concentration of Na + ions. A total of 90 cells from three different modules are subjected to PID‐s degradation and recovery. The experimental results show varying degrees of PID‐s loss and recovery among the tested cells. The analysis highlights that non‐ohmic shunts exhibit greater recovery potential than ohmic ones, a finding further verified using dark lock‐in thermography (DLIT). Furthermore, the proposed method qualitatively provides insights into the recovery potential of individual cells, establishing EL imaging as an effective tool for assessing PID‐s severity and predicting recovery. This paves the way for future advancements in PID‐s diagnostics and mitigation strategies within PV systems.