Physics-assisted machine learning for slurry drying simulation in manufacturing process of battery electrodes: A hybrid time-dependent VGG16-DEM model

In this study, we present a hybrid Physics-Assisted Machine Learning (PAML) model that integrates Deep Learning (DL) techniques with the classical Discrete Element Method (DEM) to simulate the slurry drying during a lithium ion battery electrode manufacturing process. This model predicts the microstructure evolution leading to the formation of the electrode, as a time-series along the drying process. The hybrid approach consists in performing a certain amount of DEM simulation steps, n_DEM, after every DL prediction, mitigating the risk of unphysical predictions, like overlapping particles. Our PAML model was rigorously tested by evaluating different functional metrics of the predicted electrodes, including density, porosity, tortuosity factor, and radial distribution function. We conducted an in-depth analysis of performance versus accuracy, particularly focusing on the impact of the n_DEM hyperparameter, which represents the number of DEM steps executed between two subsequent DL predictions. Despite the model being trained on a specific formulation (96% of Active Material, AM, and 4% of Carbon Binder Domain, CBD), it demonstrated exceptional generalization capability when used to extrapolate to a different formulation (94% AM and 6% CBD). This adaptability highlights the robustness of our PAML hybrid approach. Furthermore, the integration of DL significantly reduced the computational cost of the original DEM model, decreasing the processing time from 34.2 minutes per step to approximately 2 minutes per step. Our findings underscore the potential of combining ML with traditional simulation methods to enhance efficiency and accuracy in the field of electrode manufacturing.