Three-dimensional particle-resolved models of Li-ion batteries to assist the evaluation of empirical parameters in one-dimensional models

Abstract: Li-ion batteries are frequently modeled using variants of the one-dimensional approach that was initially developed by Newman and colleagues (e.g., ). Necessarily such an approach is based upon assumptions about the electrode microstructure, and quantitative predictions depend upon empirical parameters such as effective conductivities and diffusion coefficients. The present paper develops a three-dimensional model that can resolve electrode structure at the submicron scale. Although the three-dimensional model is capable of representing arbitrary electrode microstructure, the present paper considers regular arrays of spherical particles. The model is applied to evaluate approximations in one-dimensional models and to assist in establishing empirical relationships that can be used in reduced-dimension models. General relationships for effective particle radius in one-dimensional models are derived from the three-dimensional simulations. The results also provide a basis for estimating the empirical Bruggeman exponents that affect Li-ion transport within electrolyte solutions. [Copyright &y& Elsevier]