Energy storage batteries for eVTOL vehicles face the dual challenge of enabling vertical flight while meeting strict weight, safety, and range requirements for urban air mobility. eVTOLs—designed for short-haul passenger transport or cargo delivery—demand batteries with ultra-high energy density (300–500 Wh/kg) to lift their own weight plus payload, while maintaining safety in airborne applications. These systems must also support rapid charging (20–30 minutes) for high utilization rates, making them critical for the emerging advanced air mobility (AAM) industry.  

Lithium-nickel-cobalt-aluminum (NCA) and lithium-nickel-manganese-cobalt (NMC) batteries are currently the gold standard for eVTOLs, offering the highest energy density among commercial chemistries. For example, a four-passenger eVTOL might use a 150 kWh NMC battery pack weighing ~500 kg, enabling a 100-mile range with a 1,000 kg payload. Advanced cell designs, such as 4680-style cylindrical cells or large-format pouch cells, optimize space and heat dissipation. Thermal management is non-negotiable: eVTOL batteries use liquid-cooling plates with dielectric fluids (e.g., mineral oil) to maintain cell temperatures within ±2°C, preventing thermal runaway during high-power takeoffs or landings.  

Safety protocols in eVTOL batteries exceed terrestrial applications. Multilayer fire containment systems include:  

Ceramic-coated separators to prevent short circuits.  

Fire-resistant aerogel blankets between cells.  

Pressure relief valves that direct gas away from the cockpit.  

Redundant BMS with triple-redundant voltage/temperature sensors.  

Additionally, eVTOL batteries must pass rigorous aviation standards like RTCA DO-311A, which mandates fault tolerance (e.g., continued operation after a single cell failure) and crashworthiness. Some designs incorporate "battery modules" that can be isolated individually, allowing the vehicle to land safely even if part of the battery fails.  

Future advancements aim to double energy density via silicon anodes or solid-state electrolytes. Solid-state batteries, with non-flammable ceramic electrolytes, could reach 600–700 Wh/kg, enabling longer ranges and eliminating liquid cooling needs. As eVTOLs transition from prototypes to commercial fleets, energy storage systems will be the linchpin for balancing performance, safety, and operational feasibility, driving the realization of urban air taxi networks and sustainable aerial transport.