Deformation-dependent effective mobility in Structural Battery Electrolytes
Year: 2025
Type: article
Abstract: This paper considers chemical diffusion in a Structural Battery Electrolyte (SBE) under the influence of finite deformation, which serves as a first step towards the more rigorous electro-chemically coupled modeling of deformation-dependent ionic transport in SBEs. The SBE is a porous (bicontinuous) microstructure consisting of a solid (polymer) skeleton, and pores filled with a liquid electrolyte. We use computational homogenization and 3D-representation of the microstructure to compute the deformation-dependent effective mobility via direct upscaling in a two-step procedure. We solve the RVE-problem for the mechanical (equilibrium) problem under macro-scale deformation control, while adopting Neo-Hooke hyperelasticity for the fine-scale modeling of the solid skeleton. Thereby, the elastic moduli are calibrated based on experimental data for the effective response. Subsequently, for diffusion, we assume a Fickian constitutive relation and a constant mobility in the deformed setting. Pull-back to the undeformed configuration then gives the pertinent deformation dependent mobility for the fine-scale model. In the final step, we apply computational homogenization to obtain the effective mobility pertaining to the macro-scale chemical potential gradient, while noting that the RVE-problem is linear in the chemical potential for a given macro-scale deformation gradient. The numerical results show that when the macro-scale loading is of compressive nature, then the pore volume is reduced and, as a direct consequence, the effective mobility becomes smaller. More specifically, we consider a bicontinuous SBE with 37% initial porosity. Upon compressing it macroscopically by 20% strain, the effective mobility components reduce by up to 26% in undeformed configuration.
Language: English
Subfield: Computational Theory and Mathematics
Field: Computer Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,790
Funders: Vetenskapsrådet, U.S. Air Force
Awards: G284246890, Computational modeling of the electrochemical actuation of a class of carbon fiber composites, Numerical model reduction for computational homogenization of polycrystals, Modeling and computational homogenization of porous media including fluid-transport in a network of propagating fractures
OpenAlex ID: W4408973990