Investigation of Lithium-Ion Battery Degradation in Electric Aircraft Under Cycle-Progressive Loads

Electrification is a key step toward reducing aviation anthropogenic emissions; however, significant uncertainties regarding the long-term degradation behavior of electrochemical energy storage systems in electric aircraft applications still remain. Conventional degradation testing often relies on static load profiles that fail to capture the relationship between cell aging and time-varying power demands. To address this gap, this study investigates cycle-progressive load profiles in which system power demand is incrementally increased to reflect the escalating electrical requirements imposed by aging batteries on active thermal management systems. Molicel P30B lithium-ion cells are subjected to mission-representative electrical load profiles generated using the RCAIDE computational framework for an electric conventional takeoff and landing and an electric vertical takeoff and landing aircraft. Experimental results show that cycle-progressive profiles accelerate capacity fade relative to static profiles, exhibiting up to 22.1% greater state-of-health degradation and distinct shifts in incremental capacity signatures. These findings reveal the need for testing protocols that incorporate realistic coupled aging-power-demand interactions, thereby enabling a more accurate performance assessment of battery systems for electric aircraft applications.