Electro chemo mechanics and fracture of Li ion battery electrodes

2016-06-16
Capacity fade in conventional Li-ion battery systems due to chemo-mechanical degradation during charge–discharge cycles is the bottleneck in high-performance battery design. Stresses generated by diffusion-mechanical coupling in Li-ion intercalation and deintercalation cycles, accompanied by swelling and shrinking at finite strains, cause micro-cracks, which finally disturb the electrical conductivity and isolate the electrode particles. This leads to battery capacity fade. As a first attempt towards a reliable description of this complex phenomenon, we propose a novel finite strain theory for chemo-elasticity coupled with phase-field modeling of fracture, which regularizes a sharp crack topology. We apply a rigorous geometric approach to the diffusive crack modeling based on the introduction of a global evolution equation of regularized crack surface, governed by the crack phase field. The irreversible evolution of the crack phase field is modeled through a novel critical stress-based growth function. A modular concept is outlined for linking of the diffusive crack modeling to the complex chemo-elastic material response of the bulk material. Here, we incorporate standard as well as gradient-extended Cahn–Hilliard-type diffusion for the Li-ions, where the latter accounts for a possible phase segregation. From the viewpoint of the methodology, the separation of modules for the crack evolution and the bulk response provides a highly attractive and transparent structure of the multi-physics problem. This structure is exploited on the numerical side by constructing a robust finite element method, based on an algorithmic decoupling of updates for the crack phase field and the state variables of the chemo-mechanical bulk response. The performance of the proposed coupled multi-field formulation will be demonstrated with representative initial boundary value problems.
Multiscale phenomena in electrochemical and porous systems, (14 - 16 Haziran 2016)

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Citation Formats
H. Dal, “Electro chemo mechanics and fracture of Li ion battery electrodes,” presented at the Multiscale phenomena in electrochemical and porous systems, (14 - 16 Haziran 2016), 2016, Accessed: 00, 2021. [Online]. Available: http://www2.warwick.ac.uk/fac/sci/maths/research/events/2015-16/nonsymposium/pm/.