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Effective minority carrier lifetime as an indicator for potential-induced degradation in p-type single-crystalline silicon photovoltaic modules
摘要： In this paper, we report the effective minority carrier lifetime (τeff) in fresh and potential-induced degradation (PID) acceleration tested p-type single-crystalline Si modules. τeff in different regions of solar cells was measured using the microwave photoconductance decay (μPCD) method. Electroluminescence (EL), lock-in-thermography, and dark and light current–voltage (I–V ) measurements were carried out as a complementary analysis of μPCD. In addition, τeff in every stage of Si solar cell fabrication (wafer to solar cell) was measured to investigate the change of carrier dynamics. From the obtained results, a great decrease in τeff was observed in the PID-affected regions, confirming the excess non-radiative recombination centers in that region, suggesting that τeff from the μ-PCD method can be an effective indicator to judge whether PID phenomenon has occurred.
关键词： microwave photoconductance decay,p-type single-crystalline silicon,potential-induced degradation,effective minority carrier lifetime,photovoltaic modules
更新于2025-09-11 14:15:04
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Universal explanation for degradation by charge accumulation in crystalline Si photovoltaic modules with application of high voltage
摘要： It was experimentally found that surface recombination due to charge accumulation, called polarization-type potential-induced degradation (PID), occurs by applying high voltage in n-type crystalline Si photovoltaic (PV) modules. By contrast, polarization-type PID has not been observed yet in p-type crystalline Si PV modules. We investigated the effect of differences in anti-reflection coating (ARC) and the conduction type of the substrate used as a base for PV cells on PID. PID was examined for PV modules using p-type and n-type crystalline Si PV cells with a SiNx or SiNx/SiO2 stacked ARC layer. The results indicate that PID owing to charge accumulation occurs even for p-type crystalline Si PV modules by applying high positive voltage. Furthermore, we found that polarization-type PID due to charge accumulation in ARC, leading to surface recombination, is due not to the conduction type of the substrate but to the ARC structure.
关键词： potential-induced degradation,anti-reflection coating,surface recombination,charge accumulation,photovoltaic modules
更新于2025-09-11 14:15:04
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Stress and Fracture of Crystalline Silicon Cells in Solar Photovoltaic Modules – A Synchrotron X-ray Microdiffraction based Investigation
摘要： Fracture of crystalline silicon (c-Si) solar cells in photovoltaic modules is a big concern to the photovoltaics (PV) industry. Cell cracks cause performance degradation and warranty issues to the manufacturers. The roots of cell fractures lie in the manufacturing and integration process of the cells and modules as they go through a series of elevated temperature and pressure processes, involving bonding of dissimilar materials, causing residual stresses. Evaluation of the exact physical mechanisms leading to these thermomechanical stresses is highly essential to quantify them and optimize the PV modules to address them. We present a novel synchrotron X-ray microdiffraction based techniques to characterize the stress and fracture in the crystalline silicon PV modules. We show the detailed stress state after soldering and lamination process, using the synchrotron X-ray microdiffraction experiments. We also calculate the maximum tolerable microcrack size in the c-Si cells to sustain the residual stress after lamination. We further demonstrate the effect of these residual stresses on the cell fractures using the widely accepted fracture (4-point bending) tests. These test results show that the soldering and lamination induced localized residual stresses indeed reduce the load-carrying capacity of the c-Si cells.
关键词： fracture,crystalline silicon,residual stresses,synchrotron X-ray microdiffraction,photovoltaic modules
更新于2025-09-11 14:15:04
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[IEEE 2019 International Conference on Clean Electrical Power (ICCEP) - Otranto, Italy (2019.7.2-2019.7.4)] 2019 International Conference on Clean Electrical Power (ICCEP) - Application of Dust Mitigation Strategies to Single-Axis-Tracking Photovoltaic Modules in the Semi-Arid Areas of South Africa
摘要： This paper provides field generated data for single-axis-tracker (SAT) photo voltaic (PV) modules subjected to the semi-arid Northern Cape environment of South Africa. The research objectives are the investigation of the effects of dust soiling on PV module performance and the application of experimental dust mitigation methods. This includes the use of a hydrophobic anti-soiling coating and also the execution of a self-cleaning manoeuvre by the SAT systems. Two SAT systems were deployed to serve as experimental platform, from which data was obtained for a three month period (97 days). Raw data validation is established with comprehensive weather monitoring (ambient temperature, wind speed, wind direction, rainfall, pressure, and humidity), irradiance and PV module back sheet temperatures recorded, in accordance with the IEC61724 standard. An intelligent device was used to extract Current-Voltage (I-V) curves from individual PV modules. Maximum PV module power output is derived from the measured I-V curves, validated with a single-diode curve fitting routine. The comparative study between the different PV modules is done with a performance ratio (PR), defined as the temperature and irradiance corrected performance factor of a PV module. Contrary to the initial hypothesis, results indicated that the hydrophobic coating actually promoted dust soiling. The applied self-cleaning capability of the SAT system did not yield any conclusive results as a dust mitigation method. Finally, interesting in-field observations are discussed.
关键词： photovoltaic modules,self-cleaning,hydrophobic coating,performance ratio,dust soiling
更新于2025-09-11 14:15:04
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Imaging and micro-structural characterization of moisture induced degradation in crystalline silicon photovoltaic modules
摘要： Moisture induced degradation in photovoltaic (PV) modules operate via multiple chemical mechanisms commonly identi?ed by the sole use of destructive techniques. However, in such cases, e?ective use of spatial imaging techniques can aid identi?cation of certain operating mechanisms on the basis of degradation pattern characteristics. This paper presents an approach of imaging the e?ects of moisture induced degradation in crystalline silicon PV modules under damp heat (DH) test conditions using electroluminescence (EL) and dark lock-in-thermography (DLIT) imaging techniques. The a?ected regions were extracted for identi?cation of degradation products using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) micro-structural characterization technique. Consequently, combination of both imaging and micro-structural characterization techniques were used to propose the mechanism of degradation. The presented approach was instrumental in identi?cation of the e?ects of moisture induced degradation through imaging techniques, moreover the investigation also provided insights in this ?eld of work. The results present signature image patterns for identi?cation and di?erentiation of dominant chemical mechanisms under moisture induced conditions viz. tin migration at the ?nger-wafer interface and formation of silver oxide at cell cracks and edges. The ribbon interconnects was identi?ed as an active site for deposition of oxides from solder material, and aluminium electrode in presence of water as an electrolyte. Moreover, loss in interfacial adhesion between wafer, encapsulant and ?nger. In addition, material quality, manufacturing distinctions, and module design parameters seem to be responsible for observing di?erent operating mechanisms. Also, the obtained insights were applied for investigation of a 20-year-old aged PV module.
关键词： Chemical degradation,Damp heat test,Photovoltaic modules,Electroluminescence imaging,Dark lock-in thermography imaging,Moisture induced degradation
更新于2025-09-11 14:15:04
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Cryogenic delamination: mathematical modeling and analysis of an innovative recycling process for photovoltaic crystalline modules
摘要： The increasing rate of production and diffusion of photovoltaic (PV) technologies for industrial and domestic applications urges improvement of the sustainability of their demanufacturing processes in order to reduce the amount of electronic wastes. Sustainability of demanufacturing processes concerns the reduction of energy consumption, the reduction of polluting substances as well as the reduction of the effort spent in recovery of the components. No optimal process exists so far, provided a number of different approaches have been devised. A promising choice relies on the use of thermo-mechanical treatments for inducing a delamination process where interfacial bonding between layers are weakened and, finally, broken inducing delamination of the layers. In this view, the paper presents a preliminary theoretical industrialization study. We introduce a mathematical model based of the equations of thermo-elasticity to prove the feasibility of the technological process; the results of a Finite Element (FE) Analysis are then discussed to show the validity of the new sustainable demanufacturing process endeavouring the delamination process. The analysis is performed searching the optimal thermally induced cycles at cryogenic temperatures.
关键词： Thermoelasticity,Sustainability,Photovoltaic modules
更新于2025-09-11 14:15:04
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Influence of backsheet materials on potential-induced degradation in n-type crystalline-silicon photovoltaic cell modules
摘要： We investigated the influence of backsheet materials on potential-induced degradation (PID) in n-type crystalline-silicon (c-Si) photovoltaic (PV) cell modules. Silicon heterojunction PV cell modules and rear-emitter n-type c-Si PV cell modules were fabricated by using aluminum backsheets composed of poly ethylene terephthalate (PET)/aluminum/PET as well as typical backsheets. PID tests of the modules were performed by applying a negative bias in a dry environment (<2% relative humidity). Regardless of the types of cells, the modules with the aluminum backsheets showed smaller degradation. This indicates that aluminum backsheets reduce PID effects, and to alter backsheets may be a potential measure to reduce PID.
关键词： n-type crystalline-silicon,potential-induced degradation,backsheet materials,photovoltaic modules
更新于2025-09-11 14:15:04
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Data from multimodal functions based on an array of photovoltaic modules and an approximation with artificial neural networks as a scenario for testing optimization algorithms
摘要： This paper presents the data of multimodal functions that emulate the performance of an array of five photovoltaic modules under partial shading conditions. These functions were obtained through the PeV curves of a mathematical modeling and represent photovoltaic module with several local maximums and a global maximum. In addition, data from a feedforward neural network are shown, which represent an approximation of the multimodal functions that were obtained with mathematical modeling. The modeling of multimodal functions, the architecture of the neural network and the use of the data were discussed in our previous work entitled “Search for Global Maxima in Multimodal Functions by Applying Numerical Optimization Algorithms: A Comparison Between Golden Section and Simulated Annealing” [1]. Data were obtained through simulations in a C code, which were exported to DAT files and subsequently organized into four Excel tables. Each table shows the voltage and power data for the five modules of the photovoltaic array, for multimodal functions and for the approximation of the multimodal functions implemented by the artificial neural network. In this way, a dataset that can be used to evaluate the performance of optimization algorithms and system identification techniques applied in multimodal functions was obtained.
关键词： Multimodal functions,Photovoltaic modules,Artificial neural networks,Partial shading,Optimization algorithms
更新于2025-09-11 14:15:04