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

Hoffmann, Alexander; Spiegel, Sandro; Heckmann, Thilo; Scharfer, Philip; Schabel, Wilhelm

doi:10.1007/s11998-022-00660-8

Cited by 7 publications

(7 citation statements)

References 18 publications

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“…Towards higher shear rates (>10 s −1 ) the viscosity of the anode and the viscosity of the cathode slurries approach each other indicating a comparable suitability for slot‐die coating [10,33,58] . A further effect is that scrap rates due to edge elevations during electrode manufacturing can be minimized by slurries with a higher viscosity at low shear rates and shear thinning behavior [33,58–60] …”

Section: Resultsmentioning

confidence: 99%

“…[10,33,58] A further effect is that scrap rates due to edge elevations during electrode manufacturing can be minimized by slurries with a higher viscosity at low shear rates and shear thinning behavior. [33,[58][59][60] As suggested in the previous section, the different drying times may be compensated by increasing the solid content for SIB materials with a lower capacity than LIB materials. However, it can be seen from the determination of viscosity that an increase in solid content, with otherwise the same composition between LIB and SIB, leads to a further increase in viscosity.…”

Section: Hc Lfp Pbamentioning

confidence: 97%

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Challenges and Opportunities for Large‐Scale Electrode Processing for Sodium‐Ion and Lithium‐Ion Battery

Klemens,

Wurba,

Burger

et al. 2023

Batteries & Supercaps

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Sodium‐ion batteries are an emerging technology that is still at an early stage of development. The electrode processing for anode and cathode is expected to be similar to lithium‐ion batteries (drop‐in technology), yet a detailed comparison is not published. There are ongoing questions about the influence of the active materials on processing parameters such as slurry viscosity, coating thicknesses, drying times, and behavior during fast drying. Herein, the expected drying time for the same areal capacity of anodes (graphite vs. hard carbon) and cathodes (lithium iron phosphate vs. Prussian blue analogs) are compared based on respective specific capacities reported in the literature. Estimates are made for the materials’ impact on production speed or dryer length. Within the experimental part, water‐based slurries of the same composition are mixed using different active materials according to identical procedure and the viscosity is compared. When drying at a constant drying rate (0.75 g m−2 s−1), lithium iron phosphate electrodes with different areal capacities (1–3 mAh cm−2) are shown to have the highest adhesion. For high drying rates (3 g m−2 s−1) at constant areal capacity, especially the investigated electrodes based on hard carbon show that no binder migration occurs.

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Section: Resultsmentioning

confidence: 99%

Section: Hc Lfp Pbamentioning

confidence: 97%

Challenges and Opportunities for Large‐Scale Electrode Processing for Sodium‐Ion and Lithium‐Ion Battery

Klemens,

Wurba,

Burger

et al. 2023

Batteries & Supercaps

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“…[36] This reduces the reject rate during electrode production. [37][38][39] Since the same solid content and the same electrode composition with the same CMC amount was adjusted, all three HC slurries for SIB and the graphite slurry for LIB show the same behavior for the viscosity at a shear rate above 100 s À1 . In the slot-die-coating process at state-of-the-art industrial coating speeds, typical shear rates in the coating gap are above 400 s À1 .…”

Section: Slurry Flow Behaviormentioning

confidence: 99%

Process and Drying Behavior Toward Higher Drying Rates of Hard Carbon Anodes for Sodium‐Ion Batteries with Different Particle Sizes: An Experimental Study in Comparison to Graphite for Lithium‐Ion‐Batteries

et al. 2023

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Lithium-ion batteries (LIB) and sodium-ion batteries (SIB) are both based on similar intercalation/insertion electrodes of the respective alkali ions into the active materials during charging and discharging. [1] Due to the larger and heavier sodium (Na) ion, a lower gravimetric and as well volumetric capacity than with lithium can be achieved. [2,3] However, given the resource availability of active materials from sustainable raw materials, at potentially low cost, SIB is one of the most promising post-Li batteries for widespread commercialization in the coming years. [4][5][6] Electrode processing of materials for SIB is expected to be very similar to the processing of LIB materials. However, the producibility and material processing challenges of potential electrode materials for anodes and cathodes are poorly investigated.Unlike for the LIB, graphite cannot be recommended as anode material for the SIB, because the formation of a Na-graphite-intercalation compound is energetically unfavorable and has a very low capacity. [7][8][9][10] Instead, hard carbon (HC) is considered to be a promising anode active material with good electrochemical performance for alkali-metal-ion batteries, such as SIBs. [8] The low material costs, the fact that HC can be produced from sustainable raw materials, and the low electrode potential are advantageous for the use of HC as an anode material for SIB. [11,12] However, high capacity losses in the first cycles and at high current rates are still challenging. The performance characteristics of HC active materials, which result from different synthesis methods, are different. [8] The selected precursor and the carbonization conditions, namely, the carbonization temperature, influence the nongraphitic structure of the HC produced and thus, its properties. [2,8,10] The non graphitic structure of the HC offers various areas where Na ions can be deposited. These include especially the regions between the graphite-like domains consisting of micropores and defect sites. Various models describing the storage mechanism, which are controversially discussed, can be found in the literature. [2,10,13,14]

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“…Physical models have been employed for specific stages, such as discrete element modelling for structure evolution in calendering, [27] and computational fluid dynamics for air entrapment in coating. [28] However, combining stages increases complexity, and physical models often rely on empirical data from specific experiments. Data-driven models offer an alternative, less computationally complex method to explore the process, providing insights into the dependencies of manufacturing outputs on physical properties.…”

Section: Introductionmentioning

confidence: 99%

Impact of Formulation and Slurry Properties on Lithium‐ion Electrode Manufacturing

Reynolds,

Faraji Niri,

Hidalgo

et al. 2023

Batteries & Supercaps

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The characteristics and performance of lithium‐ion batteries typically rely on the precise combination of materials in their component electrodes. Understanding the impact of this formulation and the interdependencies between each component is critical in optimising cell performance. Such optimisation is difficult as the cost and effort for the myriad of possible combinations is too high. This problem is addressed by combining a design of experiments (DoE) and advanced statistical machine learning approach with comprehensive experimental characterisation of electrode slurries and coatings. An industry relevant graphite anode system is used, and with the aid of DoE, less than 30 experiments are defined to map impact of different weight fractions of active material (80–96 wt%), conductive additive (Carbon Black at 1–10 wt%) and a two‐component binder system (Carboxymethyl Cellulose (CMC) at 1–3 wt% and Styrene Butadiene Rubber (SBR), at 1–7 wt%). Using Explainable Machine Learning (XML) methods, correlations between the formulation, slurry weight percentage (30–50 wt% in water) and coating speed (1–15 m/min) are quantified. Slurry viscosity, while known to depend on the CMC concentration, is also heavily influenced by carbon black and SBR when at high concentration, as is common in research. Viscosity increasing components also improve adhesion, by improving dispersion and hindering binder migration. Conductivity of the coating on current collector is sensitive to the current collector‐coating interface, which makes it a highly useful probe. Improvements in cell capacity are observed with higher viscosity formulations (High weight percentage, CMC content), attributed to reduction in migration and slumping of the slurry on the current collector. SBR had a negative impact at any concentration due to its insulating nature, and carbon black reduces gravimetric capacity when included at high concentrations. The insights from this study facilitate the formulation optimisation of electrodes providing improved slurry design rules for future high performance electrode manufacturing.

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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

Cited by 7 publications

References 18 publications

Challenges and Opportunities for Large‐Scale Electrode Processing for Sodium‐Ion and Lithium‐Ion Battery

Challenges and Opportunities for Large‐Scale Electrode Processing for Sodium‐Ion and Lithium‐Ion Battery

Process and Drying Behavior Toward Higher Drying Rates of Hard Carbon Anodes for Sodium‐Ion Batteries with Different Particle Sizes: An Experimental Study in Comparison to Graphite for Lithium‐Ion‐Batteries

Impact of Formulation and Slurry Properties on Lithium‐ion Electrode Manufacturing

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