Characterization of Degradation under Standard Environmental Testing Methods for Crystalline Silicon Photovoltaic Modules

Abstract

Abstract. Standard environmental tests have been developed for photovoltaic (PV) modules to assess the reliability of their performance in a short period of time. These tests generate different modes of degradation by combination of environmental stresses. There is a need to differentiate between the standard tests on the basis of severity. This helps to understand the individual and combined degradation effect occurred due to temperature and humidity stress, which is the focus of the present study. In this work, standard tests viz. humidity freeze (HF), thermal cycling (TC) and damp heat test (DH) have been performed on different batches of multi-crystalline silicon PV modules. One batch of modules was subjected to combined tests wherein the three tests were performed in succession and the other batch was separately subjected to the individual tests. Spatial characterization techniques i.e. electroluminescence (EL) and dark lock-in-thermography (DLIT) imaging were used in tandem with illuminated current voltage (I-V) analysis for detection and quantification of degradation under the standard tests. The information obtained from the comparison between the different tests, on a scale of time and severity can be helpful for preliminary investigations performed on effects of the common environmental degradation factors like high temperature, high humidity and thermal ramping. The presented findings can further aid research and development on different aspects of reliability testing on PV module performance under environmental effects.

Study on the effect of finger fracture characteristics on the performance of crystalline silicon solar cell

“…The fracture value of the finger was obtained by measuring the fracture values of multiple fingers and calculating the weighted average. It was reported in the literature that the continuous fracture of multiple fingers will accelerate the decline of the solar cell power, while the substitution of multiple measured average values for real measured values will lead to errors 34,42 …”

“…It was reported in the literature that the continuous fracture of multiple fingers will accelerate the decline of the solar cell power, while the substitution F I G U R E 8 Relationship between the size of the finger fracture and three resistances (sheet resistance, finger resistance, and front contact resistance) for an area B-type finger fracture of multiple measured average values for real measured values will lead to errors. 34,42 However, because there was a virtual welding connection in the fracture of the finger, the measured fracture position and size were smaller than the actual values. A small fracture size of finger will cause a low power, while a small fracture position of finger will cause a large power.…”