A Neros Archer drone at the Modern Day Marine symposium in Washington, D.C. on Tuesday. Lance Cpl. Kiara Rawls/US Marine Corps Marines face a new strain as tens of thousands of drones are set to enter the force. Lithium batteries require special measures, and can catch fire if stored improperly. Marines say they need more drones that can speak a universal language. The Marine Corps is preparing to field tens of thousands more drones for troops to watch and attack enemy positions, and leaders say the challenge isn't just getting them into the hands of trained Marines — it's the behind-the-scenes prep that comes with. Think: batteries. Small drones rely on lithium batteries that need to be specially stored, monitored, and kept charged — and the Corps is set to receive 40,000 more drones later this year, meaning a surge of volatile batteries will need to be safely and properly managed. "If they get wet, they catch fire, and then you've got a runaway fire.…