Core-shell enhanced single particle model for LiFePO$_4$ batteries

TL;DR

This paper introduces a new electrochemical model for LiFePO$_4$ batteries that captures phase transformation dynamics using a core-shell approach, improving accuracy in simulating battery behavior.

Contribution

It presents a novel core-shell based modeling approach for LiFePO$_4$ batteries, incorporating phase transformation phenomena into the single particle model.

Findings

Model accurately captures phase transformation during lithiation/delithiation

Finite difference discretization enables efficient simulation

Parameter identification validated with experimental data

Abstract

In this paper, a novel electrochemical model for LiFePO$_4$ battery cells that accounts for the positive particle lithium intercalation and deintercalation dynamics is proposed. Starting from the enhanced single particle model, mass transport and balance equations along with suitable boundary conditions are introduced to model the phase transformation phenomena during lithiation and delithiation in the positive electrode material. The lithium-poor and lithium-rich phases are modeled using the core-shell principle, where a core composition is encapsulated with a shell composition. The coupled partial differential equations describing the phase transformation are discretized using the finite difference method, from which a system of ordinary differential equations written in state-space representation is obtained. Finally, model parameter identification is performed using experimental data from a 49Ah LFP pouch cell.