Thermal Modelling of Battery Cells for Optimal Tab and Surface Cooling Control

TL;DR

This paper introduces a new computationally efficient thermal model for battery cells that accurately captures 2D thermal dynamics and enables independent control of cooling channels, improving safety and performance.

Contribution

A novel spectral-Galerkin based battery thermal model library with reduced states, validated against high-fidelity models, enabling better control and optimization.

Findings

The four-state model accurately captures 2D thermal dynamics.

The one-state model outperforms traditional TEC models in accuracy and efficiency.

The models enable independent control of tab and surface cooling channels.

Abstract

Optimal cooling that minimises thermal gradients and the average temperature is essential for enhanced battery safety and health. This work presents a new modelling approach for battery cells of different shapes by integrating Chebyshev spectral-Galerkin method and model component decomposition. As a result, a library of reduced-order computationally efficient battery thermal models is obtained, characterised by different numbers of states. These models are validated against a high-fidelity finite element model and are compared with a thermal equivalent circuit (TEC) model under real-world vehicle driving and battery cooling scenarios. Illustrative results demonstrate that the proposed model with four states can faithfully capture the two-dimensional thermal dynamics, while the model with only one state significantly outperforms the widely-used two-state TEC model in both accuracy and computational efficiency, reducing computation time by 28.7%. Furthermore, our developed models allow for independent control of tab and surface cooling channels, enabling effective thermal performance optimisation. Additionally, the proposed model's versatility and effectiveness are demonstrated through various applications, including the evaluation of different cooling scenarios, closed-loop temperature control, and cell design optimisation.