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

• Published in: Electrochimica acta 2012-03, Vol.64, p.118-129
• Main Authors: Goldin, Graham M., Colclasure, Andrew M., Wiedemann, Andreas H., Kee, Robert J.
• Format: Article
• Language: English
• Subjects: Applied sciences; Approximation; Arrays; Batteries; Direct energy conversion and energy accumulation; Effective properties; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrode microstructure; Electrodes; Empirical analysis; Exact sciences and technology; Li-ion battery; Mathematical models; Microstructure; Three dimensional models
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2011.12.119

Li-ion batteries are frequently modeled using variants of the one-dimensional approach that was initially developed by Newman and colleagues (e.g., [2]). 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.