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Spatter formation during laser beam melting of AlSi10Mg and effects on powder quality
摘要： Cost and resource efficiency of Laser Beam Melting (LBM) highly depend on powder recycling procedures. Non-solidified powder can be sieved and reused in subsequent build cycles. However, due to quality concerns, powder recycling is not commonly practiced. One effect, which can impair the powder quality, lies in the formation and insertion of spatter particles during the melting process. In this paper, spatter particles emerging during LBM of AlSi10Mg are characterized regarding geometric (size, morphology), chemical (alloy composition, oxygen content, oxide layer thickness) properties as well as mass. Spatter particles are collected during the process using two isolation methods. Three types of spatter particles can be differentiated by their formation mechanism. It is found that spatter particles can differ significantly in oxide layer thickness and particle size. A significant share of spatter particles can be segregated by sieving. However, a certain fraction of the spatter particles will be included in the recycled powder.
关键词： Laser beam melting,AlSi10Mg,Powder recycling,Powder quality,Powder bed fusion,Powder reuse,Additive manufacturing,Reusability,Oxidation,Spatter
更新于2025-09-12 10:27:22
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Perovskite Solar Cell: Research Direction for Next 10 Years
摘要： Since the first report on a solid-state perovskite solar cell (PSCs) with a power conversion efficiency (PCE) of 9.7% under 1 sun illumination and 500 h stability at ambient conditions obtained from an unencapsulated device in 2012, PSCs have received tremendous attention from scientists and engineers working on not only materials and devices but also fundamentals. The realization of solid-state PSCs was possible due to the fact that methylammonium lead triiodide (MAPbI3) was extremely unstable in dye-sensitized solar cell structures containing polar liquid redox electrolyte. The first version of a PSC was based on a nanocrystalline perovskite with dot morphology sitting on the TiO2 surface, which evolved to a thin film layout looking similar to the conventional p?i?n junction. This initial progress of device structure enhanced PCE to about 12%, which was followed by a further increase in photovoltaic performance by exploring coating methods for high-quality perovskite films. To date, the record PCE of 25.2% was certified by Newport, a proxy for National Renewable Energy Lab (NREL) using quasi-steady-state measurement, which was posted in the best research-cell efficiency chart provided by NREL. PSCs now outperform the completions based on CIGS (PCE = 23.4%), CdTe (PCE = 22.1%), and even multicrystalline Si (PCE = 22.8%).
关键词： Perovskite solar cells,Tandem technology,Power conversion efficiency,Recycling technology,Large-area coating,Stability
更新于2025-09-12 10:27:22
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Research on China’s photovoltaic modules recycling models under extended producer responsibility
摘要： The global photovoltaic (PV) industry has been developing rapidly in recent years. We have to face the dilemma of waste PV modules at the end of their life. It is important for government to construct recycling system to collect waste PV modules in the future. This paper analyses the three recycling models under Extended Producer Responsibility (EPR) from the perspective of reverse supply chain. The Government Subsidy is taken into account in the recycling model as an incentive factor. This paper examines the level of the PV producer’s recycling responsibility which is expressed by the recycling proportion of producers. The results show that there are some general rules about recycling responsibility by comparing the results of di?erent models. What’s more, a coordinating way is designed in mixed recycling model within a certain recycling scale range in order to cut down the producer’s recycling cost. Our research shows that the coordinating way is a great method with practical value when it is di?cult for the government to implement a complete EPR system.
关键词： government subsidy,photovoltaic modules,Sustainability,remanufacture,extended producer responsibility,recycling
更新于2025-09-12 10:27:22
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Value Retention Options in Circular Economy: Issues and Challenges of LED Lamp Preprocessing
摘要： The Circular Economy is gaining recognition for its attention to increasing material circularity by proposing a set of value retention options, and organizing business, institutions, and policies for their implementation. Light emitting diode (LED) lamp recycling is becoming increasingly important due to their growing market share and precious metal content. Instead of the current shredding approach, this study applied higher value retention options, such as testing for the functionality of the bulb at the product level, manual disassembly to reuse parts at the component level, and automatic disassembly for industrial scale reuse. This study ?nds that the e?ort that is needed to implement higher value retention options (such as reuse) requires a new form of secondary business, wider networks of recycling chains, and favorable policies. It also shows that about 50% of the lamp waste stream is still functioning and economically attractive if they are remarketed. However, the demand-pull market conditions seem to be missing. For manual disassembly, the output fractions are cleaner, but it is not economically feasible due to high labor cost. On the other hand, automatic disassembly does not produce cleaner fractions due to wide design variability. Thus, this study suggests that shifting from shredding-focused-resource recovery to reuse-based-resource circularity requires a comprehensive framework that simultaneously encourages secondary market formation, collaboration between manufacturers, recyclers and companies, and the formulation of favorable reuse policies. This study applies insights from circular economy principles to LED lamp recycling, and it also contributes to the latter by identifying challenges and possible solutions.
关键词： circular economy,light emitting diode (LED) lamp,value retention options,disassembly,recycling
更新于2025-09-11 14:15:04
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Influence of Fragment Size on the Time and Temperature of Ethylene Vinyl Acetate Lamination Decomposition in the Photovoltaic Module Recycling Process
摘要： Photovoltaics is a commercially available and reliable technology with significant potential for long-term growth in nearly all global regions. Several research institutes and companies are working on recycling concepts for thin film modules and modules with crystalline cells. The establishment of recycling and reuse technologies appropriate and applicable to all photovoltaics (PV) modules is a key issue to be addressed as part of corporate social responsibility to safeguard the environment and to implement a fully material-circulated society without any waste. The copolymer ethylene-vinyl acetate (EVA) layer is a thermoplastic containing cross-linkable ethylene vinyl acetate, which is used to encapsulate the photovoltaic cells. The cells are laminated between films of EVA in a vacuum, under compression, and up to 150°C. The encapsulant’s primary purpose is to bond or laminate the multiple layers of the module together. In the photovoltaic module recycling process, the second important step (after mechanical dismantling of the frame) is EVA lamination removal. In this study, different parameters of the thermal delamination method used during the recycling process were experimentally tested and compared, and the most ecological and economical one is proposed.
关键词： recycling,photovoltaic,EVA
更新于2025-09-11 14:15:04
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[IEEE 2018 IEEE 7th International Conference on Photonics (ICP) - Langkawi, Malaysia (2018.4.9-2018.4.11)] 2018 IEEE 7th International Conference on Photonics (ICP) - Influence of Raman Pump Direction on the Performance of Serial Hybrid Fiber Amplifier in C+L-Band
摘要： This study demonstrates the simulation and experimental validation of a serial hybrid Raman/erbium-doped fiber amplifier in the C+L optical communication bands. The erbium-doped fiber is pumped by the residual Raman pump to enhance pump conversion efficiency in forward (Type A) and backward (Type B) direction. The amplifier was tested with three different input levels where the overall finding shows Type B provides better gain (average of 20dB across band) than Type A at the expense of noise figure (2dB higher).
关键词： serial hybrid fiber amplifier,recycling technique,conventional technique
更新于2025-09-10 09:29:36
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Drivers, barriers and enablers to end-of-life management of solar photovoltaic and battery energy storage systems: A systematic literature review
摘要： Distributed solar photovoltaic (PV) systems are a low-cost form of renewable energy technology that has had an exponential rate of uptake globally in the last decade. However, little attention has been paid to the potential environmental and human health related impacts associated with PV systems, if not managed properly at the end-of-life (EoL). Rare materials such as ruthenium, gallium, indium, and tellurium are essential components in PV panels, while battery energy storage systems (BESS) are composed of various chemistries (i.e. lithium-ion, lead acid, nickel cadmium, salt water, and flow batteries). An appropriate EoL management strategy for solar photovoltaic systems (i.e. PV modules, BESS) is necessary, not only to prevent and/or mitigate future environmental problems but also to reduce demand on rare earth materials. Drawn from a portfolio of 191 papers collected from Scopus and Web of Science databases between 2000 and 2018 (by 30 June 2018), a systematic quantitative literature review on solar energy systems EoL studies was conducted to examine the temporal trend of current research as well as methodological and geographical distributions of the published articles. Research has been concentrated within Europe, some parts of Asia, and North America, with experimental and modelling/simulation methods being mostly applied. The focus of this study was to compile and synthesise reported drivers, barriers, and enablers to EoL management of PV panels and BESS in the context of the circular economy. A conceptual framework is proposed to facilitate the transition of current PV system material flows and supply chain management practices to circular economy concepts. This paper also presents a future research agenda.
关键词： battery energy storage system,recycling,solar panel,photovoltaic,end-of-life management,circular economy
更新于2025-09-10 09:29:36
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Leaching of Rare Earth Metals from Phosphor Coating of Waste Fluorescent Lamps
摘要： Phosphors made from compounds of rare earth metals (REMs) are very efficient. This material needs to be recycled for recovery of REMs after the fluorescent lamps (FLs) reach end of life. This work focuses on the leaching studies of REMs from phosphor. The phosphor was recovered from the spent linear FLs by end cut-push method. After detailed characterization of phosphor, effects of parameters viz. leachant, concentration, temperature, and pulp density were studied to determine the optimum leaching conditions. By using 9% (v/v) H2SO4, 98.6% (w/w) yttrium and 96.2% (w/w) europium could be leached out from phosphor at temperature, 70 °C, time, 4 h, and pulp density, 10% (w/v). The residue generated was treated with 54% (v/v) HCl to leach out 98.9% (w/w) lanthanum, 98.2% (w/w) cerium and 96.5% (w/w) terbium at temperature, 90 °C, time, 2 h, and pulp density, 10% (w/v). Kinetic studies of leaching reactions were also carried out.
关键词： Phosphor,Leaching,Waste recycling,Rare earth metals,Fluorescent lamps
更新于2025-09-09 09:28:46
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End-of-life of silicon PV panels: A sustainable materials recovery process
摘要： In this paper, the management of end-of-life PV modules based on an advanced eco-sustainable process has been presented and discussed. The thermal removal of the polymeric compounds contained in c-Si PV modules has been investigated to separate and recover Si, Ag, Cu, Al and glass. A two-step thermal process has been employed. In the first step, the rear polymeric layer has been removed without emissions of dangerous fluorinated substances. In the second step, the remaining polymers have been completely removed with low volatile organic compounds (VOCs) emissions. The polymers degradation has been studied at combustion equivalent ratios U varying from 0.5 to 2 and at 500 °C. The materials recovery has been evaluated from an environmental point of view and optimized by considering the energy cost, through the identification of the best operating conditions, in terms of temperature, time, atmosphere and gas flow. One hour of heat treatment and a slightly oxidizing atmosphere have been enabled to separate and recover the different materials of the module. The elemental compositions of the PV sample and the residue condensed organic products have been determined. The gaseous degradation products have been characterized by gas chromatographic analysis (GC).
关键词： Recycling,Photovoltaic module,Thermal treatment,Polymer removal,Energy consumption
更新于2025-09-09 09:28:46
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Exact Solution, Endoreversible Thermodynamics, and Kinetics of the Generalized Shockley-Queisser Model
摘要： We consider the generalized Shockley-Queisser (GSQ) model, which is based on a single assumption that photocarriers and emitted photons are in chemical equilibrium and described by the Boltzmann distribution functions with the same chemical potential. The model takes into account the frequency-dependent absorption (emission), photon trapping and recycling, photocarrier multiplication, and nonradiative recombination processes. For the noninteracting photocarriers, we obtain an exact analytical solution of the GSQ model. We present the conversion e?ciency and other photovoltaic (PV) characteristics in a convenient form via the Lambert W function. Photocarrier multiplication and recombination via three-body Auger processes are also directly included in this formalism. We derive universal formulas for useful energy, thermal losses, and emission losses per absorbed photon. We show that the relation between the maximal conversion e?ciency and the photo-induced chemical potential, obtained by Henry [J. Appl. Phys. 51, 4494 (1980)] for the ideal SQ limit, is also valid in the GSQ model. In the general case of interacting electrons, in particular for the Shockley-Read-Hall processes, the solution is presented in an iterative form. We analyze photocarrier kinetics and derive a general relation between the optimal photocarrier collection time and photocarrier lifetime with respect to all radiative and nonradiative processes. Finally, we analyze ?nite mobility limitations and show that PV devices with photon trapping and recycling provide the fast photocarrier collection required by the GSQ model.
关键词： photocarrier kinetics,photon trapping and recycling,photovoltaic conversion,Lambert W function,generalized Shockley-Queisser model
更新于2025-09-09 09:28:46