The maritime sector must increasingly become more sustainable and meet climate goals. As a result, more battery-electric and hybrid ships are being built and retrofitted. Safety is crucial since the battery system is vital for maneuverability. Hence, classification societies require regular health assessments of these systems. Currently, battery capacity is measured annually through complete charge and discharge cycles onboard which is cost- and time-intensive. This project DDD-Batman (Data-Driven Degradation monitoring and prediction of BATteries for Maritime ApplicatioNs) developed methods for determining the battery ageing state based on operating data as an alternative, better method.
The development was based on both laboratory measurements of battery cells and operational data (figure in poster) collected over several years from 6 ships. A variety of different state-of-health (SOH) estimation methods have been evaluated. Among others cumulative degradation and snapshot methods [1]. Further methods that were studied in detail are presented in the poster.
An Equivalent Circuit Model based SOH estimation method led to the best results and was introduced as an accepted alternative method to the annual capacity measurement in the field [2].
[1] E. Vanem, Q. Liang, M. Bruch, G. Bøthun, K. Bruvik, K. Thorbjørnsen, A. Bakdi, Statistical Models for Condition Monitoring and State of Health Estimation of Lithium-Ion Batteries for Ships, JDMD (2024). https://doi.org/10.37965/jdmd.2024.500.
[2] Press Releases Corvus Energy – first marine ESS Supplier to enable data-driven State of Health (SOH) test, Corvus Energy (March 6, 2024). https://corvusenergy.com/corvus-energy-first-marine-ess-supplier-to-enable-data-driven-state-of-health-test-soh/ (accessed March 15, 2025).