Analysis of Solvent‐Free Intensive‐Dry‐Mixed NMC‐Based Lithium‐Ion Battery Cathodes: Numerical Investigations on Performance Determinants

Abstract

AbstractA numerical investigation on the implications of intensive‐dry mixing on the resulting cathode microstructure and hence, the electrochemical performance has been presented in this contribution. In this regard, characterization as well as scale‐resolving electrochemical performance simulations were carried out. The basis for these numerical investigations were computer generated cathode geometries, generated by means of a discrete element method simulation model, presented in our previous work. Consequently, three different stages of comminution of the conductivity additive during intensive dry mixing with nickel rich active material were incorporated into computational half cells and classified based on the simple quality parameter, bulk density. Furthermore, the possible coating phenomenon occurring during the process, to which the bulk density measurements are not susceptible, was modelled with the help of a numerical parameter called the coating factor. It was found that bulk density of cathode blends, which is a rather trivial parameter to measure from intensive dry mixed blends, could be strongly correlated to cathode performance under the consideration of solvent free manufacturing. The findings suggest that, while considering limited volume during cell design, higher bulk density of dry cathode components delivers the best performance under higher energy and low current conditions. At high power and high current condition however, a compromise between energy and power dictates the choice. Conversely, if the material mass is the constraining factor, the lower bulk density tends to perform the best due the best utilisation of the available energy.