Key considerations for cell selection in electric vertical take off and landing vehicles: a perspective

Abstract

Electric vertical take-off and landing (eVTOL) aircraft require significantly different cell considerations compared to electric vehicles, we consider a wide range of cell selection criteria, assessing the viability of commercial cell formats and chemistries for usage in eVTOLs.As battery performance has improved in recent years, all-electric aircraft have become a realistic prospect. Passenger electric vertical take-off and landing (eVTOL) vehicles have gained attention recently as a solution for intercity transport, reducing carbon emission, congestion and journey times. However, the performance demands of electrified flight are greater than that of ground-based vehicles, requiring high energy, power and safety characteristics. While electric vehicles typically use cylindrical, pouch and prismatic cells depending on the manufacturers’ needs, it is unclear which form factor is most suited to aerospace applications. This work appraises a range of commercial cells of different formats and their suitability for use in eVTOLs, considering their electrochemical, safety, cell-to-pack integration and future-proofing characteristics. The findings indicate that current prismatic cells lack the power density needed for take-off and landing. While pouch cells offer compelling energy density, there are concerns over their safety performance and ease of pack integration. While the geometry of cylindrical cells makes them difficult to pack and are unlikely to be used for emerging all solid-state chemistries, we believe they currently offer the best balance of safety and performance.