Research into Marine Battery Health to Support Adoption of New Systems
A new research effort is launching to study maritime battery health as a means of building confidence and support the adoption of hybrid and electrical systems in the shipping industry. While the shipping industry has been slow to adopt battery systems onboard, having a better understanding of the overall health of installed batteries and the available power is believed will help to increase the adoption of these systems.
The objective of the DDD-Batman project is to develop data-driven methods for diagnostics and prognostics of battery systems and to provide methods for verifying the battery state of health (SOH) based on real-time sensor measurements. Continuous operational sensor data of the temperatures, discharge rates, voltages, and impedance behavior can be used to model and forecast the degradation of the battery – showing the SOH at any time.
The research institute Fraunhofer ISE will be leading the project with participation from battery supplier Corvus, Carnival Maritime GmbH, and DNV GL. The project is sponsored by MarTERA, an EU Horizon 2020 cofound scheme, aimed at strengthening the European Research Area (ERA).
“At the moment, vessels that depend on a Li-ion battery system need an annual validation test of the battery’s SOH. At DNV GL we require an annual validation testing of a battery’s SoH for ships utilizing Li-ion battery systems for propulsion or maneuvering,” says Sverre Eriksen, Senior Principal Engineer, at DNV GL – Maritime. “This can be quite time consuming and has some limitations in the data we obtain. As batteries continue to penetrate the industry, we need to improve the data we have, especially as we see batteries in operation for longer periods.”
In addition to pure electric vessels, batteries can enable significant gains in efficiency and emissions reductions in many ship types. The goal of the DDD-Batman project is to develop better data on the health of a battery system, enabling predictive maintenance strategies, and offering a better look at the remaining useful life of the battery.
Removing the class mandated annual capacity test and replacing it with an advanced analytical model using measured onboard battery data as input will be beneficial to the maritime industry support the development of new applications and confidence in battery systems. The shipowner will no longer need to limit the vessel's operation to obtain a validated SOH. They will also be able to better monitor and evaluate how the battery is used and do needed adjustments which will save costs, provide greater predictability for maintenance, and increase security.
Corvus believes that the results of the research will help to automate existing processes. Improved operational data from the installed base will also enable Corvus to further improve sizing algorithms and models to more accurately predict how a change in the operational profile affects battery life.
“The Costa group wants to take a further important step forward along the path to emission-neutral ship operations by installing innovative battery technology on board,” says Jens Kohlmann, Vice President Asset Management Carnival Maritime GmbH. “In conjunction with Corvus Energy, we are working on the use of lithium-ion battery storage systems onboard the AIDA fleet.”
Carnival Corporation’s AIDA brand has announced plans to outfit AIDAperla with a battery storage system with an output of ten megawatt hours. It will be the largest system of its kind ever installed on a passenger ship.
“The service life of battery cells has become significantly longer in recent years. However, since battery systems are associated with high investment costs and have to work reliably, precise state of health monitoring and, ideally, extension of service life by adjusting the operating conditions is of great importance. A major obstacle at present is that although some aging processes are understood, their interaction, as well as measurement and prediction during operation, are still a huge challenge.” says Maximilian Bruch, a scientist at Fraunhofer ISE. “The targeted laboratory tests and at the same time the analysis of load profiles and operating data in real use cases make the DDD-Batman project an excellent approach to significantly increase the precision and validity of online aging monitoring. In addition to the applied development, the project contributes to the general scientific understanding of battery aging.”
The project will collect operational data from ships in addition to laboratory data and develop reliable and secure strategies for data collection, storage, and sharing. The primary focus will be on battery systems for cruise ships, including battery lifetimes, replacement strategies, life cycle assessments, and shore connection procedures.
DDD-Batman is also looking to set new standards for reliability and lifetime prognostics, deliver recommendations and give input to standards, recommended practices, and class rules for batteries. The project hopes to increase confidence in battery-powered ships, making batteries a more attractive alternative and helping to enhance shipping’s uptake of electric propulsion systems.