Batteries are fueling drone warfare. Reconnaissance quadcopters with a half-hour of flying time require a constant supply of freshly recharged batteries to keep going. Bomber drones eat up similar numbers. FPV drones are shipped with batteries that weigh more than the drones themselves.
Most drone batteries are made in China, which is why the Chinese government was able to pull the plug on battery supplies to U.S. military drone maker Skydio last month.
Skydio CEO Adam Bry reassured customers that they would quickly find an alternate source, but warned that for the next few months Skydio X10 batteries would be rationed — one per drone. The U.S. Army, which uses the X10 in the Short Range Reconnaissance role, was probably expecting a regular supply of spares, for a certified ‘Blue sUAS’ drone sourced from secure suppliers.
This is a familiar problem for Ukrainian drone makers who have already shown how to break the reliance on Chinese suppliers.
Battery Pack Basics
Break open a drone battery, and you will find a shrink-wrapped block containing smaller batteries. Large battery units, from laptops to power tools to electric bikes to EV car batteries, are all assembled from varying number of standard cells not much bigger than an AA battery.
These cells are described by their size, so an 18650 cell is a cylindrical unit about 18 millimeters in diameter and 65 millimeters in height, while a 2170 is 21mm in diameter and 70 mm high.
A typical laptop battery will contain six 18650 lithium-ion cells. The battery pack for a Tesla Model 3 Long Range made before 2018 contains 2170-type cells, no less than 4,416 of them.
While not all cells are created equal, they are essentially commodity products manufactured by the billion. They’re made mainly by big players in the Far East; China dominates but it does not have a monopoly. Other sources are readily available.
The biggest battery maker by capacity is Chinese outfit CATL, making 132 GWH of cells every year. But the next two are South Korean LG (93 GWH) and Japanese Panasonic (60 GWH), and there are two other Korean outfits, Samsung and SK, in the top ten.
To build your own drone batteries, you have to source quality cells from a reliable supplier and assemble them into battery packs. And that is exactly what Ukrainian drone maker Wild Hornets has been doing for some time.
Powering Up The Drone War
A video on social media explains Wild Hornets’ process. The building blocks for its battery packs are Samsung 50S, which are optimized for high-power applications and have a respectable 5000 mAH capacity.
The cells are arranged in blocks of 12 in a 6s2p unit (that is, 6 rows of 2 batteries) or 18 in 6s3p (6 rows of 3) configuration. These are connected with metal strips and 0.25 mm copper wiring – “we don’t economize” the presenter says in the video – spot welded into place. Spot welding is costlier than soldering, but more reliable. The completed unit is then securely shrink-wrapped with multiple layers of tough plastic.
While you can make your own battery packs at home (explainer here) it is not a project for novices. Wild Hornets, which has built up the skills, processes and equipment for drone assembly on a large scale, seems to have mastered the technique.
The end result costs a total of $65 for small batteries and $90 for large, similar to commercial drone batteries. What matters though is the quality and reliability of the product, which is literally a matter of life and death. That is worth paying extra for.
“A year ago we bought batteries from other manufacturers but we did not always get good feedback,” the video presenter said. “Without a good battery, everything else is wasted. We realized we had to make good quality batteries.”
Wild Hornet’s own-brand products solve problems such as batteries failing while the drone is still over Ukrainian lines or a substandard unit running down before reaching its target.
Securing The Supply Chain
As Wild Hornets shows, local drone battery production is possible even for a small outfit reliant on fundraising for its production. The group has also undertaken more complex challenges, such as making the flight controllers, which are the ‘brains’ of its drones, on a robot production line.
Other Ukrainian makers have similarly found ways to break free of a supply chain which is often dominated by Chinese manufacturers. Atlas Dynamics claims that it makes everything in its drones itself – including the thermal imaging cameras. After almost three years of war, Ukrainian makers are learning to be increasingly self-sufficient. With a goal of producing more than 1.5 million drones this year, they cannot rely on international suppliers to meet their needs.
Meanwhile, Russia is still heavily reliant on imported electronics. This includes some from U.S. companies including Texas Instruments, according to a report by the Kyiv School of Economics.
The U.S. military currently buys small drones like the SRR by the hundred rather than by the thousand; the Army are acquiring 918 in this year’s budget. The latest move by China should be a wake-up call if the U.S. is ever to come close to the scale of drone production that Ukraine has already achieved.
