Understanding slurry mixing effects on the fast charging capability of lithium-ion battery cells: Methodology and case study

The fast charging capability of lithium-ion batteries is mainly constricted by mass transport limitations within the electrolyte that fills the porous network of the electrodes. The onset of a parasitic side reaction referred to as lithium plating strongly depends on the micro-structure of the batteries’ anode. In this study, a methodology is introduced that allows to investigate the influence of the slurry preparation on electrode properties and the resulting fast charging performance of graphite anodes. Therefore, an in-situ lithium plating detection technique based on the differential charging voltage is used to connect electrode properties with the fast charging capability of the anodes in lithium-ion cells. Following this approach, changes in the particle size distribution due to a high intensity mixing process using pilot-plant scaled planetary mixers are linked to a modification of the pore size distribution and the electrode tortuosity. Eventually, a deteriorated fast charging performance is connected to the increased tortuosity caused by high intensity mixing.