Charging Phase Health Indicators for Battery State-of-Health Estimation: A Systematic Comparison of CC, CV, and Combined Approaches under Cross-Battery Validation

Abstract:Accurate State-of-Health estimation is essential for safe battery operation and cost-effective maintenance. Although numerous health indicators have been derived from constant-current (CC) and constant-voltage (CV) charging phases, their effectiveness under realistic cross-battery validation remains insufficiently studied. This work addresses this gap through a systematic comparison of CC-only, CV-only, and combined indicator sets using rigorous Leave-One-Battery-Out (LOBO) validation on the NASA battery aging dataset. Four CV-phase indicators and CC phase duration are evaluated individually and in combination. Results show that the combined CC+CV approach achieves the best performance (R2 = 0.874), confirming that CC and CV phases capture complementary degradation information. Moreover, a 119% performance gap is observed between standard 5-fold cross-validation and LOBO validation, indicating that conventional evaluation overestimates practical accuracy. Based on these findings, practical guidelines are provided for indicator selection under data and computational constraints.

This paper has been published in Eksploatacja i Niezawodnosc. Please cite the published version

Machine Learning (cs.LG)

arXiv:2607.23482 [cs.LG]

(or arXiv:2607.23482v1 [cs.LG] for this version)

https://doi.org/10.48550/arXiv.2607.23482 Focus to learn more arXiv-issued DOI via DataCite (pending registration)

https://doi.org/10.17531/ein/220211 Focus to learn more DOI(s) linking to related resources

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