Investigation of dominant degradation mode in field‐aged photovoltaic modules using novel differential current‐voltage analysis approach

Abstract

Photovoltaic (PV) modules are susceptible to various types of defects and degradations (D&Ds) under field‐operating conditions, which affect their performance and reliability. These D&Ds have non‐uniform distribution in the PV modules, which makes it difficult to distinguish amongst multiple D&Ds using a single characterization technique. In the present work, a simple non‐destructive characterization approach called differential current‐voltage (DIV) analysis using current‐voltage (I‐V) measurements have been developed for investigation of the dominant degradation mode in the cells of modules, wherein consecutive cells have been partially shaded while measuring the I‐V curve of the modules. For this purpose, a batch of crystalline silicon PV modules operating under hot and humid climatic conditions for 20 years has been investigated. A correlation has been established between the trend of percentage change in modules' electrical parameters during DIV measurements and the dominant degradation mode present in the cell under investigation. The trend of change in short circuit current and voltage at maximum power point has been identified as key electrical parameters to identify the dominant degradation mode in the cell. To analyse the trends of DIV analysis, the effect of prominent degradation modes on the module parameters has been investigated using electrical simulations. The investigated PV modules have been cross‐characterized through microscopic inspection and electroluminescence imaging to identify various D&Ds present in the investigated modules. The results of cross‐characterization substantiate the findings of DIV analysis. The presented DIV approach can be used for the analysis of non‐uniform degradation in the PV plants under field‐operating conditions.

Temperature profiles of field-aged photovoltaic modules affected by optical degradation

“…EL imaging is interesting especially for quantifying resistive losses in old PV modules affected by cracks and severed metal grids. Moreover, the technique could also be very useful in detecting encapsulant degradation [ 40 ]. Degraded encapsulant reduces the luminescence signal that gets through to the detection camera.…”

Field studies of PERC and Al-BSF PV module performance loss using power and I-V timeseries

“…The (Current-Voltage) I-V data collected at standard test conditions (STC) or in field were analyzed using open-source data analysis tools. We demonstrate that the data analysis pipeline is not only flexible enough to capture nonlinear performance degradation (Hashemi et al, 2020;French et al, 2021;Hashemi et al, 2021;Theristis et al, 2021;Lindig et al, 2022;Livera et al, 2022a), but also capable of extracting performance loss and changes in electrical features from I-V curves at outdoor conditions (Li et al, 2023;Meena et al, 2022;Jain et al, 2020;Livera et al, 2019). Furthermore, our pipeline can construct data-driven network models of degradation pathways, allowing for the comparison of degradation mechanism among different variants (Nalin Venkat et al, 2023).…”