The Mechanics of Light Elevated Temperature Induced Degradation (LeTID) on PERC Module: A Review

Passivated emitter and rear contact (PERC) cells are financially commanding and rapidly increasing PV system in the energy market. Its efficiency decreases over time because of the Light-Induced degradation (LID) that follows countless hours of exposure to light (above 50^oC temperature), and collectively is termed as Light and Elevated Temperature Induced Degradation (LeTID). Every PERC solar cell module experiences the LeTID effect significantly. Excessive hydrogen injection into Si bulk creates the atomic-level defect structure, which is mainly guilty for the LeTID. Therefore, the normal lifetime of PERC modules has become less, and ultimately levelized cost of electricity (LCOE) of installed systems is increasing. All c-Si types of PV devices are degraded by 5%, whereas the PERC module is degraded by up to 10% due to LeTID. Even, 16% power loss took place due to this kind of degradation, though an efficiency of 23.6% has been recorded for the PERC solar cells. The mono-crystalline Si solar cell module degraded (2-3.6) % while multi-Si solar cells module can be degraded up to (3.8–7.5) %. This study has covered the introduction and characterization of the LeTID, exploring the influencing factors for LeTID and mitigation techniques of decadence. LeTID on PERC module is altered depending on the variations of weather and the variety of cells used in PERC modules, which have been reported in this review. These insights will be helpful in finding a better understanding of the LeTID effect on the PERC module.