InterPore2021

Modeling lithium diffusion in battery cathodes considering chemo-mechanically induced damage

31 May 2021, 19:35

1h

Poster (+) Presentation (MS4) Swelling and shrinking porous media Poster +

Speaker

Jeffery Allen (National Renewable Energy Laboratory)

Description

This talk will present a 3D, continuum-level damage model for simulating Lithium diffusion within generated Li$_x$Ni$_{0.5}$Mn$_{0.3}$Co$_{0.2}$ (NMC 532) secondary cathode particles. The primary motivation of the particle-level model is to inform cathode-particle design and determine charging profiles that reduce cathode fracture. The model considers NMC 532 secondary particles containing an agglomeration of anisotropic, randomly oriented grains. The model predicts that secondary-particle fracture is primarily due to non-ideal grain interactions with slight dependence on high-rate charge demands. The model predicts that small secondary-particles with large grains develop significantly less damage than larger secondary particles with small grains. Finally, the model predicts most of the chemo-mechanical damage accumulates in the first high-rate cycles. This chemo-mechanical "damage saturation'' effect indicates that initial secondary-particle fracture occurs within the first few cycles, while long-term cathode degradation is not solely chemo-mechanically induced.