Recover possibilities of potential induced degradation caused by the micro‐cracked locations in p‐type crystalline silicon solar cells

Abstract

Potential induced degradation (PID) has been affecting the performance, durability, and reliability of crystalline Si solar cells/modules. The authors demonstrate that micro‐cracks also act as the additional recombination centers, which reduce short‐circuit current density (Jsc), open‐circuit voltage (Voc), and the effective lifetime of carriers in solar cells, in PID condition. This hypothesis was confirmed by external quantum efficiency measurements and microwave photo‐conductance decay method at the micro‐cracked areas before and after PID stress tests. In addition, the PID recovery was made significantly but non‐fully for the laminated micro‐cracked modules owing to the electrical PID recovery method. In addition, the authors showed and discussed the challenging problems in recovering the performance of the PID‐affected micro‐cracked solar modules without lamination. The achieved results from 11 cycles of PID stress/recovery tests with the same duration of PID stress and recovery processes showed that an exponentially decreasing function fits the correlation between the relative losses of Pmax, Voc, fill factor (FF), and Jsc due to the PID stress process and the number of the PID stress/recovery cycles. This provides a model for the estimation of the relative losses of Pmax, Voc, FF, and Jsc due to the PID stress process versus the number of the PID stress/recovery cycles. Finally, based on the decreasing tendency in the performance loss of the PID‐affected laminated micro‐cracked solar modules after PID stress/recovery cycles, the authors suggest that cyclic PID tests with suitable conditions might be a reasonable approach to control PID.

Current–voltage characteristics of silicon based solar cells in the presence of cracks: MD simulations

“…Studies on multiple cracked PV modules indicated that the reduction in output power depends on the crack size, orientation, and location [22]. In [23], the authors demonstrated that the micro-cracks present in crystalline silicon solar cells/modules acted as recombination centers and affected the lifetime of carriers. On the other hand, an analysis of formation of cracks considering their distribution and orientation indicated that the cells with cracks oriented parallel to bus-bars are more critical, due to the higher potentially electrically insulated cell area insulated by the crack pattern [24].…”