Progress in Photovoltaics最新文献

This paper investigates, by modeling, the potential for high-value recycling of silicon wafers recovered from end-of-life PV modules. Technology for PV module recycling is making steady progress, both at recycling companies and R&D institutes, and it is possible that as a result, soon a stream of wafers or wafer fragments recovered from waste modules will become commercially available. Recycling the silicon for manufacturing of new PV modules is an opportunity both for reduction of cost and reduction of environmental footprint of PV. In this paper, we analyze possibilities for recycling of wafer fragments as feedstock for new silicon ingot growth. This could save up to about 0.16 kWh/Wp energy for production of the new PV system. Compared with lower value applications of the recovered silicon, the potential value and energy savings when used as feedstock for ingot growth are considerably higher. This paper presents the possibilities and challenges for recycling wafer fragments from the point of view of dopant type and resistivity control, and mitigation of the impact of recombination activity from possible increased impurity levels or related to boron. Because in current PV production a rapid transition to n-type wafer doping is taking place, the paper also considers the question what can be done with p-type doped recycled wafer material. We illustrate how application for perovskite–silicon tandem cells helps to mitigate possible performance loss from metallic impurities or boron. The application in tandem cells is perhaps the only realistic approach to make economically worthwhile use of recycled B-doped silicon as feedstock for silicon ingot growth.

Lead halide perovskites have demonstrated significant potential for photovoltaic (PV) applications over the past 10 years. Perovskite solar cells (PSCs) stability, however, continues to limit their commercialization, and the inability to compare previous stability data to assess possible directions for increasing device stability is caused by a lack of effectively established unified stability testing and disseminating standards. In this article, we suggest applying machine learning (ML) to improve the thermal, chemical, and structural stability of PSCs. Data normalization and data augmentation are common preprocessing steps that are where the process starts. Then, using the Modified Grasshopper Optimisation Algorithm (MGO), feature selection techniques are used to remove unnecessary or irrelevant features. Finally, there is a novel machine learning technique that uses support vector machines (ESVM) that are based on entropy to forecast the stability classification of stable/unstable. The proposed reaches an accuracy of 0.99% far better than the proposed methods.

It is common practice in PV system simulation to use the De Soto model, which describes how to use the 1-diode equivalent circuit model for modules. De Soto's model scales the shunt with irradiance, making it disappear toward zero W/m². Also, the commercial software PVsyst uses a parameterization that reduces the shunt effect when the irradiance goes down. However, the solar cells that make up a module typically do not have an illumination-dependent shunt. We therefore investigate the origin of the intensity-dependent apparent shunt in modules. We show that this apparent shunt (derived from the slope of the quasi-linear region from I_SC onwards) is a misinterpretation for module I-V curves and has little to do with a shunt conductance, although this slope method serves well for determining the shunt conductance of individual cells. Instead, the module I-V curve slope of the quasi-linear region from I_SC onwards is strongly influenced by even small I_SC mismatches between the cells. Such mismatch can occur from small illumination inhomogeneity even for A+ solar simulators in the laboratory, or from cell production variation. Abandoning the practice of using the I-V curve slope to determine the shunt value for equivalent circuit models of modules (and the corresponding shunt scaling in the De Soto model or PVsyst) contributes to physically more meaningful I-V curve parameterizations and bears the opportunity for further improved accuracy of PV system energy yield prediction.

In this work, novel PET-based frontsheet materials with UV-cured coatings were developed and investigated. UV-curing urethane acrylates were selected as innovative, fluorine-free coating systems. Polyurethane coatings exhibit excellent UV resistance, chemical and moisture resistance and, thus, high durability in outdoor applications. A homogeneous application without coating defects such as bubbles, voids or detachments was achieved. Material tests with cross-cut tests showed no separation from the PET substrate. The water vapor transmission rates and the physical (optical and thermal) and chemical properties of the novel polymeric frontsheets were measured and compared with uncoated reference systems and products already on the market. The aging-related changes after irradiation and humid heat storage were investigated and described in detail. Based on this comprehensive study, the newly developed frontsheets can be considered a suitable alternative to polymeric frontsheets with fluorine-containing top layers.

A growing number of gigawatt-scale photovoltaic (PV) power plants are being established in hot desert regions worldwide, which are favored for their vast available land, high solar irradiance, long sunshine hours, and relatively low maintenance needs. This study combines insights from global PV experts on degradation rates, failure mode and effects analysis (FMEA), and desert weather conditions to develop a hot desert test cycle (HDTC). The average degradation rate for PV modules installed in hot desert regions over the past 10 years is estimated to be around 1.63% per year. Eighteen failure modes were identified and analyzed using FMEA. According to the results, the main degradation mechanisms include UV light-induced degradation (UVLID), thermomechanical failures in interconnects and fingers, light-elevated temperature-induced degradation (LeTID), and abrasion of the glass and antireflection coatings. A radar map comparison shows that desert environments experience UV exposure, ambient, and module temperatures that are more than twice as high as those in moderate climates. The HDTC protocol was developed based on FMEA results and desert-specific weather conditions. It includes tests for desert UV exposure, temperature cycles, mechanical loads, and sand/brush abrasions. To ensure consistency across countries, there is a plan to establish an internationally recognized standard that complements existing IEC standards. As the industry grows, desert regions are expected to place greater emphasis on adopting desert-specific testing standards for the qualification and evaluation of PV modules.