On Hybrid Fuel Cell and Battery Systems for Maritime Applications
Time: Fri 2022-05-13 10.00
Location: F3, Lindstedtsvägen 26 & 28, Stockholm
Subject area: Chemical Engineering Chemical Engineering
Doctoral student: Ariel Chiche , Tillämpad elektrokemi
Opponent: Professor Lars Eriksson,
Supervisor: Professor Carina Lagergren, Tillämpad elektrokemi; Professor Göran Lindbergh, Tillämpad elektrokemi; Universitetslektor Ivan Stenius, Farkostteknik och Solidmekanik
Hydrogen is seen as a key player in leading to a sustainable energy sector and decarbonizing the transport sector. Proton Exchange Membrane Fuel Cells (PEMFCs) consume hydrogen and oxygen to generate water, heat and electricity. If designed properly, a hydrogen-fuelled system can significantly increase the endurance of vehicles without increasing the weight or volume of the energy system, which makes it a promising solution for maritime applications. To take advantage of the high density of energy in hydrogen and of power in batteries, a sizing strategy for hybrid systems was developed and implemented for an underwater vessel and a rescue boat, considering various constraints, e.g. neutral buoyancy for underwater vehicles. Several types of storage for reactants were compared and their thermal properties were included in the sizing strategy. To understand the behaviour of fuel cells in an underwater environment, i.e. a closed environment without presence of oxygen, an experimental lab-scale setup was built, and various hydrogen supply methods were tested. Finally, modelling of the hybrid system was used to compare different energy management strategies (EMSs).
The developed sizing strategy, tested through real power profiles, demonstrates that an optimized hybrid system becomes more compact and lighter than a battery system when the length of the mission increases. Such a system can also compete in terms of weight and volume with a diesel engine and help reduce the environmental impact of a vehicle. The heat balance analysis shows that the fuel cell is the major heat contributor, regardless of the combination of reactants storage units. The experimental work highlights that the fuel cell should deliver a low current density at a high relative humidity in order to limit the waste of hydrogen and increase the performance of the stack. The symmetric purging strategy appears to increase the stability of the stack over time. It is also shown that it is crucial to select an adapted EMS for each mission in order to fulfil it. Some EMSs tend to limit the hydrogen consumption while others deplete more battery power. To conclude, it is relevant to use fuel cell systems for maritime applications, and has the potential to increase the length of the missions performed.