A new method to perform lithium-ion battery pack fault diagnostics – Part 3: Adaptation for fast charging

Abstract

Electric Vertical Take-Off and Landing (eVTOL) aircraft are expected to become ubiquitous in the future Urban Air Mobility (UAM) landscape. Several eVTOL aircraft propelled using Lithium-ion batteries are under development. However, despite the early spotlight, the manufacturers need to ensure safe long-term operation of the vehicles including strict checks on battery-related hazards. On the other hand, fast charging of eVTOL batteries is crucial to enable multiple flights per day and justify the economics of UAM. This work is aimed at contextualising battery safety for eVTOL through the modification of a battery fault diagnosis algorithm for fast charging. The algorithm was developed in Parts 1 and 2 of the paper to use the charging cycle data for detecting disconnection faults but tested only for low charging currents. This paper adapts the algorithm for fast charging through a novel technique termed as Partial Incremental Capacity (PIC). The PIC method was developed using experiments at single cell and supercell level before integrating it into the algorithm. Finally, the fault detection ability of the adapted algorithm was validated using a real-life eVTOL battery module. Thus, the updated version of the algorithm facilitates fault diagnosis while charging fast, making it ideal for implementation in eVTOL.