CFD model of slot die coating for lithium-ion battery electrodes in 2D and 3D with load balanced dynamic mesh refinement enabled with a local-slip boundary condition in OpenFOAM / Alexander Hoffmann in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 20, N° 1 (01/2023)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 20, N° 1 (01/2023) . - p. 3-14 Titre : CFD model of slot die coating for lithium-ion battery electrodes in 2D and 3D with load balanced dynamic mesh refinement enabled with a local-slip boundary condition in OpenFOAM Type de document : texte imprimé Auteurs : Alexander Hoffmann, Auteur ; Sandro Spiegel, Auteur ; Thilo Heckmann, Auteur ; Philip Scharfer, Auteur ; Wilhelm Schabel, Auteur Année de publication : 2023 Article en page(s) : p. 3-14 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Accumulateurs lithium-ion Electrodes Enduction par filière Mécanique des fluides numériques La mécanique des fluides numérique (MFN), plus souvent désignée par le terme anglais computational fluid dynamics (CFD), consiste à étudier les mouvements d'un fluide, ou leurs effets, par la résolution numérique des équations régissant le fluide. En fonction des approximations choisies, qui sont en général le résultat d'un compromis en termes de besoins de représentation physique par rapport aux ressources de calcul ou de modélisation disponibles, les équations résolues peuvent être les équations d'Euler, les équations de Navier-Stokes, etc. La CFD a grandi d'une curiosité mathématique pour devenir un outil essentiel dans pratiquement toutes les branches de la dynamique des fluides, de la propulsion aérospatiale aux prédictions météorologiques en passant par le dessin des coques de bateaux. Dans le domaine de la recherche, cette approche est l'objet d'un effort important, car elle permet l'accès à toutes les informations instantanées (vitesse, pression, concentration) pour chaque point du domaine de calcul, pour un coût global généralement modique par rapport aux expériences correspondantes. Domaines d'application : La CFD est particulièrement employée dans les domaines des transports, pour étudier notamment le comportement aérodynamique des véhicules (automobile, aéronautique, etc) conçus. La CFD est également utilisée dans le domaine des installations critiques telles que les salles de serveurs. Elle permet de réaliser une représentation 3D de la salle, comprenant toutes les informations relatives aux équipements informatiques, électriques et mécaniques. On obtient une carte graduée des différentes zones de chaleur présentes, ce qui permet de détecter les zones critiques et les points chauds (ou "hot spots"). Revêtements Index. décimale : 667.9 Revêtements et enduits Résumé : Slot die coating is a state-of-the-art process to manufacture lithium-ion battery electrodes with high accuracy and reproducibility, covering a wide range of process conditions and material systems. Common approaches to predict process windows are one-dimensional calculations with a limited expressiveness. A more detailed analysis can be performed using CFD simulations, which are often based on in-house code or closed-source software. In this study, a two-phase CFD model in two and three dimensions was created in OpenFOAM with the intent to provide a method for more detailed investigations of the slot die coating process with open access to source code and files. A custom boundary condition enables the proper description of the wetting behavior in the two-dimensional model. The combination of standard no-slip boundary conditions at the substrate boundary with the volume-of-fluid solution algorithm leads to a method-related air entrainment, which was prevented by allowing local slip at the dynamic wetting line at the upstream meniscus in the two-dimensional model. Additionally, a load-balancing dynamic refinement algorithm was implemented to minimize the computational effort and increase the ease of use of the simulation environment. The simulation was validated by comparing the simulated process limits to experimental observations, showing good agreement. As a result, this model enables detailed analyses regarding the influences of slot die geometries, material properties, and process parameters on the coating stability and wet-film profile. Note de contenu : - EXPERIMENTAL MATERIALS AND METHODS : Material properties - Numerical methods - RESULTS AND DISCUSSION : 2D-model - Table 1 : Dry composition of the anode slurry used in this study - Table 2 : Patch names and assigned boundary conditions for the two-dimensional numerical simulations - Table 3 : Patch names and assigned boundary conditions for the three-dimensional numerical simulations - Table 4 : Computational effort for different mesh resolutions and refinement methods DOI : https://doi.org/10.1007/s11998-022-00660-8 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-022-00660-8.pdf?pdf=button Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38777 [article]

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High-speed slot-die coating of primer layers for Li-ion battery electrodes : model calculations and experimental validation of the extended coating window depending on coating speed, coating gap and viscosity / Sandro Spiegel in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 21, N° 2 (03/2024)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 21, N° 2 (03/2024) . - p. 493-505 Titre : High-speed slot-die coating of primer layers for Li-ion battery electrodes : model calculations and experimental validation of the extended coating window depending on coating speed, coating gap and viscosity Type de document : texte imprimé Auteurs : Sandro Spiegel, Auteur ; Alexander Hoffmann, Auteur ; Julian Klemens, Auteur ; Philip Scharfer, Auteur ; Wilhelm Schabel, Auteur Année de publication : 2024 Article en page(s) : p. 493-505 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Accumulateurs lithium-ion Caractérisation Enduction par filière Primaire (revêtement) Revêtements Index. décimale : 667.9 Revêtements et enduits Résumé : In the battery industry, very thin primer layers are used to improve electrode adhesion on substrates or act as blocker layers to prevent corrosion in case of aqueous cathodes. For these material configurations, high-speed coating is mandatory to ensure the economic viability of the process. One way to realize high-speed coating is a set-up including a slot die and a vacuum box to stabilize the coating bead. Knowledge and prediction of the coating window of thin wet film thicknesses is crucial to design the production process. Therefore, the influence of coating gap and viscosity of shear-thinning fluids on the coating window is investigated with the help of various model fluids. In addition, a prediction model for the calculation of the coating window for high-speed slot-die coating with vacuum box is developed. This model is shown to be valid for the prediction of the coating window for the investigated material systems and coating gaps over the investigated range of coating speeds up to 500 m min−1. For a material system, which corresponds to a real material system for adhesive primer coatings, it is possible to reach a target wet film thickness of 20–25 µm. This would correspond to a layer thickness of 0.5 µm for a solid content of 2–2.5 wt%. Note de contenu : - EXPERIMENTAL METODS AND MATERIALS : Slurry preparation - Experimental coating set-up and coating window characterization - RESULTS AND DISCUSSION : Prediction of process stability systems - Validation of the model - Table 1 : Calculated factors and exponents of equation - Table 2 : CMC content of the used model fluids - Table 3 : Power-law parameters of the investigated material - Table 4 : Ranges of shear rate of the investigated coating gaps and coating speeds DOI : https://doi.org/10.1007/s11998-023-00877-1 En ligne : https://drive.google.com/file/d/17hIPyd8QtYMw8OWK2qCN7fv_6bZaCokf/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=40772 [article]

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Investigation of edge formation during the coating process of Li-ion battery electrodes / Sandro Spiegel in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 19, N° 1 (01/2022)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 19, N° 1 (01/2022) Titre : Investigation of edge formation during the coating process of Li-ion battery electrodes Type de document : texte imprimé Auteurs : Sandro Spiegel, Auteur ; Thilo Heckmann, Auteur ; Andreas Altvater, Auteur ; Ralf Diehm, Auteur ; Philip Scharfer, Auteur ; Wilhelm Schabel, Auteur Année de publication : 2022 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Accumulateurs lithium-ion Caractérisation Electrodes Enduction par filière Enrobage (technologie) Formulation (Génie chimique) Mélange Index. décimale : 667.9 Revêtements et enduits Résumé : In this manuscript, a method to reduce superelevations of lateral edges in cross-web direction during slot die coating of shear-thinning slurries for Li-ion battery electrodes (LIB) was developed. Therefore, the impact of the inner slot die geometry on the edge elevations was investigated. These elevations of the coating could be almost eliminated by optimizing the flow profile at the outlet of the slot die by modification of the internal geometry. This adaption is an essential step in optimizing the coating quality of slot die coating for battery electrodes to significantly reduce coating edges and, hence, the resulting production reject during the coating step of the industrial roll-to-roll process. It was also shown that lateral edges of the coating can be influenced explicitly by process parameters such as volume flow and gap between slot die and substrate. This correlation has already been shown for other shear-thinning material systems in previous works, which is now confirmed for this material system. At the beginning, the influence of different internal geometries on the formation of the edge elevations was shown. Finally, for the shear-thinning electrode slurry used in this work, optimal dimensions of the previously determined inner geometry for the slot die outlet were found. The optimization was performed for a state-of-the-art electrode area capacity (approximately 2.2 mAh cm−2). The results enable a significant reduction of defects and reject in the coating step of large-scale production of LIB electrodes in the future, adding to a more sustainable battery production. Note de contenu : - EXPERIMENTAL METHODS AND MATERIALS : Formulation, mixing, and preparation - Experimental setup and process parameters - Characterization methods - RESULTS AND DISCUSSION : Influence of coating speed - Influence of dimensionless gap - Influence of shim geometries - Table 1 Composition of the solid components of the anode slurry - Table 2 Process parameters and geometrical parameters used in the experiments for the different shim configurations DOI : https://doi.org/10.1007/s11998-021-00521-w En ligne : https://link.springer.com/content/pdf/10.1007/s11998-021-00521-w.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=37150 [article]

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