Spatially resolved lithium-ion battery simulations of the influence of lithium-nickel-manganese-cobalt-oxide particle roughness on the electrochemical performance

This publication deals with the influence of the roughnesses of single lithium-nickel-manganese-cobalt-oxide-based active material particles on the electrochemical behaviour. A roughness model is used to create particles with a defined roughness depth. Subsequently, comparative calculations are performed using a 3D spatially resolved electrochemical model under different operating conditions. The results show that for small C-rates below 1C, the usage of the widespread assumption of smooth and spherical active material particles in models is justified. For higher C-rates, the particle's shape and roughness are not negligible. Small, rough particles show the best performance characteristics for high rate applications. For operation in the diffusion-limited state (low diffusion coefficient and high C-rate), the smallest absolute diffusion length represents a better correlation in terms of utilizable capacity compared to the volume-specific active surface area.