Bridging physics-based and equivalent circuit models for lithium-ion batteries

TL;DR

This paper introduces a novel circuit-based implementation of a P2D lithium-ion battery model that accurately simulates discharge behavior and provides insights into electrochemical processes, bridging physical and equivalent circuit modeling approaches.

Contribution

It presents a new transmission line circuit implementation of the P2D model, enabling accurate simulation and better understanding of battery electrochemistry.

Findings

Circuit model agrees well with physical simulations in voltage and concentration.

The model helps analyze overpotential contributions from different processes.

Demonstrates the utility of circuit models in battery analysis.

Abstract

In this article, a novel implementation of a widely used pseudo-two-dimensional (P2D) model for lithium-ion battery simulation is presented with a transmission line circuit structure. This implementation represents an interplay between physical and equivalent circuit models. The discharge processes of an NMC-graphite lithium-ion battery under different currents are simulated, and it is seen the results from the circuit model agree well with the results obtained from a physical simulation carried out in COMSOL Multiphysics, including both terminal voltage and concentration distributions. Finally we demonstrated how the circuit model can contribute to the understanding of the cell electrochemistry, exemplified by an analysis of the overpotential contributions by various processes.