New Electrolyte Enhances Stress Resilience of Lithium-Ion Batteries in Drones, Expanding Potential for Secondary Uses

In the evolving landscape of aerial electric vehicles, the robustness of lithium-ion batteries (LiBs) is pivotal, especially for vertical takeoff and landing (VTOL) capabilities.

A recent study, titled "Lithium-Ion Battery Power Performance Assessment for the Climb Step of an Electric Vertical Takeoff and Landing (eVTOL) Application" published in ACS Energy Letters, marks a significant breakthrough that enhances LiB performance in drones, also enabling battery reuse in less demanding environments.

Lithium-Ion Challenges in Drones

Lithium-ion batteries (LiBs) are popular for efficiently storing substantial energy in compact designs, particularly in drones revolutionizing agriculture for heightened efficiency and precision. These rechargeable batteries enhance crop management and optimize yields.

However, the ubiquity of LiBs does not exempt them from shortcomings, particularly when confronted with the demanding power requirements of specific applications. Notably, the stress encountered during a drone's takeoff poses a considerable challenge for these batteries, potentially resulting in damage and a shortened overall lifespan.

While lithium-ion polymer batteries are often favored for hobby drones, traditional LiBs stand out for their superior energy density, making them more suitable for heavyweight drones involved in tasks like delivering cargo to remote areas.

It is important to know the factors influencing the longevity of LiBs to solve this problem. The recent study presents a potential breakthrough for enhancing LiB performance in vertical takeoff and landing (VTOL) applications for aerial electric vehicles.

The innovative aspect of the research lies in the development of a new electrolyte, designed to tackle challenges associated with LiB stress during demanding operations like drone flights, and hints at the prospect of repurposing these "stressed out" batteries for more sustainable reuse in less demanding scenarios.

LiB Stress Experiments: Challenges and Repurposing for Conventional Power

A team led by Ilias Belharouak and Marm Dixit conducted experiments to understand how stress can affect LiBs. They developed a set of LiB cells with a specially designed, fast-charging, and discharging electrolyte.

The cells were subjected to an intense 45-second discharge, draining 15 times their optimal capacity to simulate the high-power draw experienced during vertical takeoff. Results indicated that under these high-stress conditions, none of the tested cells endured beyond 100 cycles, with diminished performance evident around 85 cycles.

Following the initial stress test, the LiB cells were subjected to a more normal, lower-rate power draw and then recharged. While the cells partially retained their capacities under low-rate conditions, they quickly failed when exposed again to rapid current drain conditions.

The findings indicate that commonly used LiBs in drones may not possess the necessary attributes for sustained high-stress operations. Nonetheless, researchers propose retiring these "stressed" batteries for more typical power demands like battery backups and energy-grid storage.

This highlights the need for further research into alternative battery technologies suitable for vertical takeoff and other high-power scenarios. The challenges identified in LiBs used in drones offer opportunities for innovating battery design to meet specific demands. As vertical takeoff electric vehicles rise in prominence, developing resilient batteries becomes crucial for long-term efficiency.