1,721,002 research outputs found
Numerical and Experimental Study of High‐Speed Laser Cutting of Copper Current Collectors: Process Optimization for Quality Assessment
Full text linkEnsuring high-edge quality in battery current collectors is crucial for improving battery performance and preventing potential safety issues. Defects such as uneven cuts, spatter, and excessive remelted zones can negatively impact the current collectors' electrical conductivity and mechanical integrity. Laser cutting offers advantages over mechanical methods by enabling faster processing, higher precision, and greater energy concentration. This study models and predicts defect occurrence under varying process parameters, focusing on the interaction between a single-mode continuous-wave (CW) laser and a copper current collector foil. Key factors influencing edge profile defects and cutting quality are investigated through experimental analysis and numerical simulation. A Computational Fluid Dynamics (CFD) model based on the volume of fluid method identifies parameters affecting the physical phenomena and optimal cutting conditions. Model validation is achieved by comparing experimental results across a range of process parameters associated with distinct defect formation modes. This model enables the prediction of defect types across a wide spectrum of laser speeds (2–25 m s−1), power levels (200–1000 W), and foil thicknesses (8–16 (Formula presented.)). Findings serve as a guideline for selecting process parameters when using current collectors of varying materials and thicknesses. © 2025 The Author(s). Advanced Materials Technologies published by Wiley-VCH GmbH
Weldability and mechanical properties of dissimilar laser welded aluminum alloys thin sheets produced by conventional rolling and Additive Manufacturing
Full text linkThe production of parts involving the combination of different materials has gained a lot of interest in recent
years as a strategy for achieving weight reduction. Particular attention has been paid to the joining process of
mechanical components obtained with different production processes. This paper aims at studying the feasibility
of laser welding to join rolled 6082-T6 thin sheet to A357 sheet produced by Laser-based Powder Bed Fusion
(LPBF). The role of welding parameters, LPBF scan strategy and post heat treatment on the weld bead formation
has been studied by means of microstructural and mechanical characterization. The results showed that a higher
welding speed reduces the porosity in the weld bead obtaining values of about 5% in terms of percentage of fused
area, while the post heat treatment of the LPBF sheet has the greatest influence on the final properties of the joint
compared to the scanning strategy used. In particular, a complete T6 heat treatment of the additive sheets leads
to an ultimate tensile strength of about 200 MPa closes to the reference condition 608
Elucidating the effects of metal transfer modes and investigating the material properties in wire-arc additive manufacturing (WAAM)
Full text linkStudies have shown the influence of WAAM process parameters on mechanical properties, bead formation, dimensional accuracy, and microstructure. However, metal transfer modes and their interactions with input variables have not been investigated thoroughly. Therefore, short/spray, pulse and double pulse modes were investigated in this study at different current levels. Bead-on-plate trials were conducted by depositing ER70S-6 wire to investigate bead morphology, dilution, microstructure, and hardness. The study was supported by a detailed statistical approach including analysis of variance (ANOVA) and regression analysis. Similarly, the combined effects of hatch distance and current were studied on bead formation in multi-layer deposits. Moreover, a thin wall and a cubic structure were deposited to realize the WAAM capability for larger depositions. The microstructures of thin wall and cubic structure were analyzed using optical microscopy (OM) and scanning electron microscopy (SEM). The study concludes that metal transfer modes at various currents significantly influence bead geometry, microstructure and hardness. The microstructure of bead-on-plate trials show fine lamellar structure at low current in all modes. Higher current results in coarse grains with a polygonal and columnar morphology. The hardness shows a decreasing trend as the current increases. The combined effects of current and hatch distance alter bead morphology; however, an optimized combination yields smoother surfaces. The microstructure of thin wall showed a slight anisotropy along the building direction. The presence of small pores was witnessed from OM and SEM images. Similarly, the cubic structure showed a more homogeneous microstructure with much lower porosity. The hardness profile of the thin wall exhibited small fluctuations along the building direction, while that of the cubic structure was more uniform
Experimental investigation on the effect of spot diameter on continuous-wave laser welding of copper and aluminum thin sheets for battery manufacturing
Full text linkWelding of dissimilar materials, particularly copper and aluminum alloys, has gained considerable industrial interest in many different electric and electronic fields, such as the production of lithium-ion batteries for automotive applications. The differences in physical and chemical properties of these materials make fusion welding processes difficult to apply due to the formation of hard and brittle intermetallic compounds that impair both mechanical and electrical performance. In this paper, the effect of spot diameter on dissimilar laser autogenous lap-welding of copper and aluminum was studied. Experiments were conducted using a mid-power fiber laser source equipped with a galvo scanner and two different focal lengths to obtain two different spot diameters. The results showed that a smaller spot diameter promoted the formation of sound weld beads with better control of penetration depth, reduced mixing of the base metals and lower laser power requirements. By selecting the correct process parameters, good mechanical properties and low contact resistance could be obtained with both focal lengths. SEM-EDX analysis confirmed that a smaller spot diameter minimized the formation of copper rich phases in the weld bead
The effect of process parameters on the high-speed cut quality of Li-ion electrodes using a single mode continuous fiber laser
Full text linkCoated Al and Cu current collectors are employed in the production of Li-ion batteries (LIBs) serving as cathodes and anodes, respectively. The increasing demand and the need for net zero-defect cutting quality are driving industrial production towards fast and reliable technologies. Laser cutting of LIB electrodes is an efficient and cost-effective alternative to conventional mechanical methods, enabling high accuracy and less damaged active material while maintaining high processing speeds. Thanks to remote laser technology flexibility, several combinations of process parameters, electrode material, and thicknesses of the electrode sandwich have been studied. This material variety discussed in the literature reflects the need of the industry to exploit different solutions. Currently, electrode cutting mainly involves the application of short pulse nanosecond (ns) fiber laser. However, the fast-advancing technology of laser manufacturing (including laser sources, optics and scanning heads) allows for new opportunities to improve process productivity and quality. This study evaluates the interaction between a single mode (SM) continuous wave (CW) source and LIB electrodes, exploring the effects of laser power and scanning speed (up to 11 m/s) on thermal defects. These include clearance width and heat affected zone (HAZ) for the anode, as well as HAZ width and the quantity of spherical defects detached from the aluminum foil for the cathode. This investigation identified a significant reduction of defects for both materials when higher speeds are set. Specifically, high-quality cuts were achieved at 5.5 m/s for the anode and 4.4 m/s for the cathode, with a clearance width kept below 20 μm and HAZ under 30 μm
Dissimilar laser welding of high-thickness Cu/Al plates for high-current density electrical batteries
Full text linkElectrical batteries connecting is a crucial phase in the fabrication of electrical vehicles. It is usually performed using high-quality lasers focused
on narrow spot, to overcome the low optical absorptivity of copper and/or aluminum and displaced with high-speed scanner to accomplish the
production rate. In applications where the current density is high (naval, heavy transport, etc) the busbars used for the electrical connections are
thick (0.8-1 mm) increasing the difficulties of having joints with no defects. In this paper, an in-depth analysis of the impact of laser power,
welding speed, and innovative scanning strategy on joint quality is presented for lap welding of nickel-plated copper (0.8 mm) to AA1050 alloy
(3 mm). Process optimization involves achieving the desired weld area while controlling metal-mixing indices to limit the formation of brittle
intermetallic compounds, cracks and voids. Weld joint quality assessment, including metallographic examination, microhardness tests and SEM-
EDX analysis is presented and discusse
High speed laser cutting of ultrathin metal foils for battery cell production
No full textLaser-based manufacturing has become a key enabling technology in the production of batteries and battery cells for the e-mobility field. Several applications, in fact, have already been industrialized, such as laser-based welding, cutting, stripping, and cleaning. Among all those technologies, laser cutting, in particular, has to deal with several very stringent constraints: the presence of highly reflective materials (aluminum and copper), very low thicknesses (6-12 mu m), on-the-fly processing, and high quality of the cutting surface. According to those considerations, the present paper deals with the application of remote cutting of 12 mu m thick aluminum and 6 mu m thick copper foils by means of a galvo scanner and two different fiber laser sources: single mode constant wave and nanosecond pulsed wave ones. The experimental activity is devoted to understanding the feasibility of the process and to point out the pros and cons of the two different lasers involved. The cutting edges are analyzed by means of optical and SEM microscopy, in order to characterize cutting quality. The process is also characterized in terms of maximum achievable speed in order to understand the limits of both lasers and galvo scanning systems
Environmental Impact, Mechanical Properties, and Productivity: Considerations on Filler Wire and Scanning Strategy in Laser Welding
Full text linkSustainability, as well as high-quality outcomes, pose significant challenges within the context of current manufacturing cycles, in alignment with European strategies aimed at decarbonization. This framework encourages a systematic evaluation of manufacturing processes in terms of their performance and carbon footprint. One sector where this is particularly relevant is the production of batteries for electric mobility, thanks to its exponential growth. Out of all the processes involved, laser welding stands out as being a critical step since it offers potential energy savings through optimization. With the dual goals of achieving mechanical strength and environmental sustainability, this study investigates alternative solutions for laser welding of aluminium sheets.
Different laser welding configurations are tested to evaluate the effect of process setups on weld quality and carbon emissions across different productivity scenarios.
The key findings can be summarized as follows: (1) the selection of welding setup significantly influences both quality and sustainability requirements; (2) the optimal conditions for meeting strength requirements may diverge from those aimed at minimizing environmental impact; (3) the choice of the final solution is influenced by the specific industrial scenario. The study specifically demonstrated that aluminium alloys can be welded with higher quality (porosity below 1% and Equivalent Ultimate Strength up to 204 MPa) when filler wire is introduced alongside an active wobbling scanning strategy. Conversely, filler wire can be omitted in scenarios prioritizing high-productivity and low-carbon emissions, such as when employing a linear scanning strategy, resulting in a reduction of equivalent carbon emissions by up to 140%.Sustainability, as well as high-quality outcomes, pose significant challenges within the context of current manufacturing cycles, in alignment with European strategies aimed at decarbonization. This framework encourages a systematic evaluation of manufacturing processes in terms of their performance and carbon footprint. One sector where this is particularly relevant is the production of batteries for electric mobility, thanks to its exponential growth. Out of all the processes involved, laser welding stands out as being a critical step since it offers potential energy savings through optimization. With the dual goals of achieving mechanical strength and environmental sustainability, this study investigates alternative solutions for laser welding of aluminum sheets. Different laser welding configurations are tested to evaluate the effect of process setups on weld quality and carbon emissions across different productivity scenarios. The key findings can be summarized as follows: (1) the selection of welding setup significantly influences both quality and sustainability requirements; (2) the optimal conditions for meeting strength requirements may diverge from those aimed at minimizing environmental impact; (3) the choice of the final solution is influenced by the specific industrial scenario. The study specifically demonstrated that aluminum alloys can be welded with higher quality (porosity below 1% and equivalent ultimate strength up to 204 MPa) when filler wire is introduced alongside an active wobbling scanning strategy. Conversely, filler wire can be omitted in scenarios prioritizing high-productivity and low-carbon emissions, such as when employing a linear scanning strategy, resulting in a reduction of equivalent carbon emissions by up to 140%
Influence of process parameters on the properties of AlCoCr2FeMo0.5Ni high-entropy alloy coatings produced with laser directed energy deposition
Full text linkAerospace industry is constantly seeking new advanced materials with high-temperature properties. Since turbine engines are subject to arduous operating conditions, the alloys used for this application are required to exhibit high fatigue, creep, oxidation, and corrosion resistances. The emerging high-entropy alloys (HEAs) show a positive potential for replacing nickel superalloys in turbine components. High-entropy alloys are composed by five or more principal elements, which generate simple crystal structures—mostly body-centered cubic (BCC) and face-centered cubic (FCC) —that are stable at elevated temperatures. High-entropy alloy fabrication typically employs traditional methods, which impose strong limitations in geometric freedom and microstructure control. Additive manufacturing represents a promising alternative, since it allows us to overcome some of the drawbacks associated with subtractive technologies. In this research, AlCoCr2FeMo0.5Ni high-entropy alloy was processed using laser directed energy deposition technology with the aim of achieving a homogeneous deposition, free of defects, and well adherent to the substrate. Single-track and multitrack tests were carried out with different combinations of laser power, scanning speed, and powder feed rate. A preliminary evaluation of the results using an optical microscope revealed a correlation between the defects and the process parameters, enabling the identification of the optimal print setup. An in-depth analysis at a scanning electron microscope was performed to assess the microstructure and distribution of alloying elements. Additionally, microhardness tests were carried out to confirm the uniformity of phases within the deposition. Finally, the analysis of deposition morphology yielded three-dimensional maps and surface roughness values
Magnetic Behavior and Loss Assessment of Additively Manufactured Fe-Si alloys
No full textThis study deals with the production and characterization of soft magnetic materials produced by means of additive manufacturing technologies. In particular, the laser-powder bed fusion has been used developing different silicon-iron alloys. The focus is to provide the BH magnetization trends, as well as the specific losses, for a wide range of supply frequency of a set of additively manufactured soft magnetic materials. Ad hoc specimens, including 'as build' and 'annealed' samples, have been tested in order to address the complete scenario about their applicability in advanced electrical machines. Consequently, the present document has to be considered as a reference where the readers that do not have the possibility to print or test soft AM materials can find useful data to start the designs and simulations of their own applications
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