Continuum Representation for Simulating Discrete Events of Battery Operation

Abstract

A mathematical approach for representing the discrete events in the cycling studies of lithium-ion batteries as a continuum event has been proposed to generate charge/discharge curves for number of battery cycles. Simulations of up to 5000 cycles have been performed using this technique using the solid-phase diffusion model. A nonlinear electrochemical engineering model, which describes the galvanostatic charge/open-circuit/discharge processes of a thin-film nickel electrode, has also been investigated to test and validate the computational performance of the continuum representation technique. Finally, the tested technique is implemented for an existing full-order pseudo-two-dimensional lithium-ion battery model that has several coupled and nonlinear partial differential equations in multiple domains. The continuum representation, which is expressed as a function of a dependent variable in time , works efficiently for several cycles with very minimal model initialization efforts and computation cost. However, it is not ideal for state detection.