Rest-Free State-of-Charge Algorithm for Lithium-Ion Batteries Under Wide C-rate Conditions for Unmanned Underwater Vehicles
Year: 2026
Type: article
Abstract: This paper presents a state of charge (SOC) estimation algorithm designed for unmanned underwater vehicles (UUVs) that operate continuously under low current conditions with intermittent high current phases from propulsion and fuel cell (FC) charging. The algorithm combines terminal voltage estimation with internal resistance compensation during low current operation and applies coulomb counting in high current events to minimize voltage-induced errors. A polarization voltage relaxation mechanism enables accurate transition back to voltage-based estimation. Experimental validation using a 72 [Ah] lithium-ion pouch cell under simulated UUV load profiles demonstrated a maximum SOC error of 3.00% and a final error of 1.80%, reducing long-term drift compared with conventional coulomb counting (5.98%). The results confirm that the proposed method maintains high SOC accuracy in endurance-critical missions and offers a reliable approach for efficient UUV battery management.
Authors: Je Yeong Lim, Jong-Hun Lim, Dong Hwan Kim, Do Hyeon Kim, Jeong Soo Ko, Jaein Lee, Byoung Kuk Lee
Institutions: Sungkyunkwan University, Agency for Defense Development
Language: English
Subfield: Automotive Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,490
OpenAlex ID: W7127150636