The high cost of Lithium-ion battery systems is one of the biggest challenges hindering the wide adoption of electric vessels. For some marine applications, battery systems based on the current monotype topologies are significantly oversized due to variable operational profiles and long lifespan requirements. This paper deals with the battery hybrid energy storage system (HESS) for an electric harbor tug to optimize the size of the battery system. The impact of battery hybridization was investigated on three key performance indicators inclusive of cost, system efficiency, and battery weight. The design life of the battery system is considered to be 10 years, and NMC and LTO cell technologies are used as high-energy (HE) and high-power (HP) battery cells. The HESS design is based on a parallel full-active architecture with a rule-based energy management strategy. The results of this research indicate that battery hybridization can reduce the system cost by around 28% and 14% in comparison with a monotype battery with LTO and NMC cells, respectively. Although no noticeable difference in system efficiency is observed between the monotype system and HESS, battery hybridization reduces the total weight of the battery cells by more than 30% compared to monotype topology. This study implies that the hybridization of battery systems could be a promising solution to reduce the cost and weight of large battery packs in electric vessels.

In the context of the maritime transportation sector electrification, battery hybridization has been identified as a promising manner of meeting the critical requirements on energy and power density, as well as lifetime and safety. Today, multiple promising battery hybridization topologies have been identified, while there is not a level playing field enabling comparison between different topologies. This study bridges this gap directly by proposing a generic hybrid battery energy storage system (HBESS) design and evaluation framework in full-electric marine applications that accounts for the key design requirements in the system topology conceptualization phase. In doing so, generalized key component models, such as battery cell models, aging models, power converter models, and thermal models, are established. Additionally, given the selected key requirements in this study, the case study comparing one baseline monotype design and two HBESS topologies has shown the clear advantage of battery hybridization. Furthermore, we find that, depending on the topology selection and the specific load scenario being considered, power converter devices can also worsen the key performance indexes.

Electrochemical energy storage technologies play a key role in wide adoption of electric waterborne transport systems. Currently, lithium-ion (Li-ion) is the leading battery technology in electric and hybrid maritime applications. However, specific operational requirements such as power peaks and long sailing distances remain a concern with respect to typical Li-ion batteries, mainly due to the limitations in terms of energy and power density as well as safety. While batteries used in most of marine applications are based on established Li-ion technologies, other mature storage technologies such as supercapacitors could be suitable for waterborne applications. Additionally, the next generation battery technologies such as solid-state batteries show promise for addressing some limitations of Li-ion batteries. These alternative technologies have the potential to transform the landscape of electric marine transport systems. Focusing on waterborne transport systems, this paper provides a review and a comparative analysis of common Li-ion batteries. Additionally, the alternative electrochemical energy storage technologies including supercapacitor and solid-state batteries are investigated and compared to Li-ion batteries. This research provides valuable insights into the advancements and prospects of electrochemical energy storage system for waterborne transport systems.