Keywords

State of Health; Lithium-Ion Battery; PatchTST; Physics-Infromed Machine Learning

Abstract

Accurately forecasting the state of health of lithium-ion batteries is critical for improving performance, reliability and lifetime in energy storage applications. Battery capacity degrades into a nonlinear pattern over cycling due to electrochemical processes where neither purely data driven nor physics-based models can capture alone. This study looks at a hybrid framework combining that PatchTST patch-based transformer architecture with physics-based features derived from the solid electrolyte interphase and pseudo two-dimensional models. Physics inspired proxy features were computed from cycling data and concatenated with electrochemical measurements as added input channels before patch segmentation. There are five model configurations that were evaluated on the TJU NCA battery dataset: two standalone physics models, one data-driven transformer, and two hybrid variants. All transformer-based models were evaluated at the cycle level in real mAh units. The base PatchTST model got a MAE of 20.542 mAh and R2 of 0.9969, showing that the patch-based transformer learned battery degradation trajectories. The PatchTST+P2D outperformed the PatchTST+SEI in all metrics, supporting the hypothesis that multidimensional electrochemical variables provide more degradation context than scalar proxies. The results emphasize the promises and current limitations of physics-based transformer architectures for battery SOH prediction.

Thesis Completion Year

2026

Thesis Completion Semester

Spring

Thesis Chair

Rui Xie

College

College of Sciences

Department

Statistics

Thesis Discipline

Data Science

Language

English

Access Status

Open Access

Length of Campus Access

None

Campus Location

Orlando (Main) Campus

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