Micro aluminum-air batteries for extended operational duration of small-scale quadrotors.

Small-scale quadrotors, typically defined as centimeter-scale in size and tens of grams in weight, are increasingly being utilized in applications such as agricultural monitoring or search and rescue operations. These vehicles are typically powered with lithium-ion batteries. However, vehicle operational efficiency and capability are often compromised by the limited energy density of these batteries, resulting in short operational duration. This work explores a high-energy chemistry, aluminum-air (Al-air), as a power source to significantly extend the operational duration of small-scale quadrotors. Rapid corrosion of the aluminum anode in existing Al-air systems has been a barrier to adoption in applications where long-term operation is required. However, corrosion is less of a concern in the small-scale quadrotor application, where the battery is typically under continuous use over a short period of time. The electrochemical and packaging design of a micro-Al-air pouch cell battery is optimized for two operating points: an energy density of 325 [Formula: see text] above a power density of 500 [Formula: see text], and an energy density of [Formula: see text] [Formula: see text] above a power density of 800 [Formula: see text], both of which far surpass the performance of equivalent commercial lithium-ion batteries. A 3D-printed small-scale quadrotor platform is used to evaluate flight duration. The micro Al-air battery delivers 13.1 min of flight time, compared to the 4.5 min of flight time provided by the commercial micro lithium-ion battery. This work demonstrates the feasibility of Al-air batteries that simultaneously possess sufficiently high power density to achieve small-scale quadrotor flight, and sufficiently high energy density to achieve extended duration of that flight.