Periodic Reporting for period 2 - SEABAT (Solutions for largE bAtteries for waterBorne trAnsporT)
Reporting period: 2022-07-01 to 2023-12-31
The International Maritime Organization targets 50% lower annual greenhouse gas emissions from maritime transport by 2050 compared to 2008, and even pursues efforts towards phasing them out entirely. Electrification (retrofitted or newbuilds) is one of the solutions to reach this target, and the market for electrified ships is large. However, the technology is not yet mature and batteries for maritime use are considerably more expensive than automotive batteries. Ships are built in small series and the battery solutions are typically bespoke, leading to low economies of scale and high assembly costs. On top of that, the battery systems that are used, are not specifically designed for maritime applications. A single type of battery is used for both high-energy missions (e.g. for maintaining cruising speed) as well as high-power peaks (e.g. fast charging, manoeuvring). However, a single battery technology cannot cover all the necessary requirements. The result is that the selected batteries cannot be used in their optimal working point, causing rapid capacity reduction and thus oversizing to guarantee a battery lifetime of ~10 years. The oversizing brings high costs, which are an important barrier to increase the market share of electrified ships. The challenge is to substantially reduce the cost of large waterborne transport battery systems.
The overall objective of SEABAT is to develop a hybrid energy storage system (HESS) based on:
(1) modularly combining high-energy and high-power batteries,
(2) novel converter concepts to facilitate the above and
(3) production technology solutions derived from the automotive sector.
A modular approach will reduce component costs (battery, convertor) so that unique ship designs can profit from economies of scale by using standardised low-cost modular components. The hybridization ensures that not only the amount of modules but also the overall electrical properties (e.g. required energy and power) can be tailored to the ship. The concept is suitable for existing and future battery generations and high-power components that may have higher power densities or are based on different chemistries. The foreseen outcome is an optimal solution, minimising the battery footprint and reducing the oversizing (from up to 10 times down to max. 2 times), validated as a 300 kWh system (full battery system test) at TRL 5, and virtually validated up to 1 MWh and above.
Furthermore, the project will work towards a roadmap for type approval and a strategy towards standardisation for (among others) ferries and short sea shipping. The solution will deliver a 35-50% lower total cost of ownership (TCO) of maritime battery systems, including 15-30% lower CAPEX investment, 50% lower costs of integration at the shipyard and a 5% investment cost recuperation after the useful life in the vessel.
The overall objective of SEABAT is to develop a hybrid energy storage system (HESS) based on:
(1) modularly combining high-energy and high-power batteries,
(2) novel converter concepts to facilitate the above and
(3) production technology solutions derived from the automotive sector.
A modular approach will reduce component costs (battery, convertor) so that unique ship designs can profit from economies of scale by using standardised low-cost modular components. The hybridization ensures that not only the amount of modules but also the overall electrical properties (e.g. required energy and power) can be tailored to the ship. The concept is suitable for existing and future battery generations and high-power components that may have higher power densities or are based on different chemistries. The foreseen outcome is an optimal solution, minimising the battery footprint and reducing the oversizing (from up to 10 times down to max. 2 times), validated as a 300 kWh system (full battery system test) at TRL 5, and virtually validated up to 1 MWh and above.
Furthermore, the project will work towards a roadmap for type approval and a strategy towards standardisation for (among others) ferries and short sea shipping. The solution will deliver a 35-50% lower total cost of ownership (TCO) of maritime battery systems, including 15-30% lower CAPEX investment, 50% lower costs of integration at the shipyard and a 5% investment cost recuperation after the useful life in the vessel.
SEABAT so far has worked towards a finalized module design ready for manufacturing and assembly, whereby all components are available and approach for testing has been established. This design is based on market needs, requirements and a thorough concept study.
(1) Market Needs
The research analysis has highlighted a future system-cost target of approximately 250-300 € / kWh with production volumes that should settle between 3 and 4 GWh per installation. Main bottlenecks for widespread implementation are: patents, certification for personnel, temperatures, humidity and the consequences of external fire. The main challenges are: the cost of onshore energy, battery cost, specific energy, ageing and related replacement costs.
(2) Requirements
The performance of 30 marine battery systems from 15 different suppliers has been studied and reported. SEABAT identified 33 different relevant battery properties, which were grouped to 9 topics: costs, energy, power, lifetime, thermal management, safety, ease of mechanical integration, ease of electrical integration and the capabilities of the battery management system.
(3) Concept & feasibility study + battery architecture
Three HESS topologies with novel converter concepts were explained, evaluated, and compared towards a baseline state-of-practice mono-type battery topology: (1) Converter integrated into the battery modules, (2) Switching between individual cells, (3) Partial power converter integrated into the battery modules. The evaluation and comparison is done via a generic optimization and modelling process. Topology 1 was deemed most performant and developed further in the project.
(4) detailed battery design & component prototyping
Each component has then been designed, procured and/or produced. Following important components & software elements have been designed within the project and are identical for both module or string types: module DC/DC converter & controller, string inductance & controller, casing, BMS slave & master, cooling plate, thermal management, and master controller. EMC analysis and performance validation was performed to confirm proper operation.
(5) Manufacturing
By using techniques from the automotive sector, SEABATs production line is capable of (in term) mass producing the battery modules. The current prototype manufacturing line is capable of producing 3 modules per week, including validation thereof. During the assembly preparation phase, an extensive analysis of the interfaces took place, covering mechanical, electronic, thermal, and communication aspects. The assembly process’ flow diagram and assembly steps were written out, along with the identification of de-risking measures for the module assembly process
(6) Validation & verification
The final step in SEABAT is the validation of the complete hybrid energy storage system. For this, the test set-up description is available and the final test program is being established. The validation of the modules and it’s components is underway, but the overall validation is part of the final period of the project.
(1) Market Needs
The research analysis has highlighted a future system-cost target of approximately 250-300 € / kWh with production volumes that should settle between 3 and 4 GWh per installation. Main bottlenecks for widespread implementation are: patents, certification for personnel, temperatures, humidity and the consequences of external fire. The main challenges are: the cost of onshore energy, battery cost, specific energy, ageing and related replacement costs.
(2) Requirements
The performance of 30 marine battery systems from 15 different suppliers has been studied and reported. SEABAT identified 33 different relevant battery properties, which were grouped to 9 topics: costs, energy, power, lifetime, thermal management, safety, ease of mechanical integration, ease of electrical integration and the capabilities of the battery management system.
(3) Concept & feasibility study + battery architecture
Three HESS topologies with novel converter concepts were explained, evaluated, and compared towards a baseline state-of-practice mono-type battery topology: (1) Converter integrated into the battery modules, (2) Switching between individual cells, (3) Partial power converter integrated into the battery modules. The evaluation and comparison is done via a generic optimization and modelling process. Topology 1 was deemed most performant and developed further in the project.
(4) detailed battery design & component prototyping
Each component has then been designed, procured and/or produced. Following important components & software elements have been designed within the project and are identical for both module or string types: module DC/DC converter & controller, string inductance & controller, casing, BMS slave & master, cooling plate, thermal management, and master controller. EMC analysis and performance validation was performed to confirm proper operation.
(5) Manufacturing
By using techniques from the automotive sector, SEABATs production line is capable of (in term) mass producing the battery modules. The current prototype manufacturing line is capable of producing 3 modules per week, including validation thereof. During the assembly preparation phase, an extensive analysis of the interfaces took place, covering mechanical, electronic, thermal, and communication aspects. The assembly process’ flow diagram and assembly steps were written out, along with the identification of de-risking measures for the module assembly process
(6) Validation & verification
The final step in SEABAT is the validation of the complete hybrid energy storage system. For this, the test set-up description is available and the final test program is being established. The validation of the modules and it’s components is underway, but the overall validation is part of the final period of the project.
In the project, 2 battery strings will be built and combined in a battery pack. Each string contains a series of respectively 12 high-energy battery modules or 12 high-power modules with integrated DC/DC converter. The high-energy battery modules contain battery cells with a low C-rate, low cycle life and high energy content (NMC), while the high-power battery modules contain battery cells with a high C-rate, high cycle life and low energy content (LTO). The amount of modules per string determines the maximum output voltage (up to 1500V), the amount and type of strings then determines the maximum power and energy. SEABAT’s battery modules are rated for maritime use, with an innovative casing, thermal management, power management etc. A sizing tool and cost/KPI evaluation tool are available to optimally scale the battery.
While the innovations mentioned above have been further proven in simulation, with more detailed results available from the module design, production has started also verify and validate the modules in a Power Hardware In The Loop physical test. The outcome of the overall research shall be a significant step towards electrified ships, which on its turn will drastically reduce (greenhouse gas) emissions. Furthermore, the research strengthens Europe’s knowledge on batteries and strengthens the industrial network to design, produce, (re)manufacture, install, deploy and recycle them.
While the innovations mentioned above have been further proven in simulation, with more detailed results available from the module design, production has started also verify and validate the modules in a Power Hardware In The Loop physical test. The outcome of the overall research shall be a significant step towards electrified ships, which on its turn will drastically reduce (greenhouse gas) emissions. Furthermore, the research strengthens Europe’s knowledge on batteries and strengthens the industrial network to design, produce, (re)manufacture, install, deploy and recycle them.