Conceptual Challenges for Crashworthy Battery-Electric Commercial Aircraft: Review

The need for more sustainable aviation has led to various new electric commercial aircraft concepts. This electrification introduces large batteries required for propulsion into the powertrain. Although safety assessments on component level have been conducted, some questions regarding the integration of such batteries into aircraft certified under FAR- or CS-25 regulations remain open. These include the crashworthiness of conceivable battery locations. This paper reviews challenges in state-of-the-art battery-electric aircraft designs, taking into account current developments in battery technologies and regulatory specifications. The aspects are analyzed within the context of conventional crash concepts. Cargo compartment and engine nacelles are identified as the most realistic options for battery storage, as accessibility issues may present a critical obstacle for batteries located in the wing box. Reviewing future battery technologies shows that mechanical deformation should be prevented for lithium-ion batteries as well as for all-solid-state batteries, which often are regarded as inherently safe with respect to thermal runaway. Difficulties in achieving a crashworthy design are therefore evident in particular when placing batteries in the cargo compartment. Still, very few studies have been published on this issue, which is also not covered by current regulations for large airplanes. More research is needed on local battery level as well as on global aircraft level to achieve certifiable battery-electric commercial aircraft.