When four NASA astronauts orbited the moon for 10 days aboard Artemis II earlier this year, lithium-ion batteries kept them connected to Earth, kept their navigation working, and kept their spacecraft from freezing or overheating. Making sure those batteries could handle the trip was no easy task — and it turns out that part of the solution involved making batteries fail on purpose.
Researchers at the National Laboratory of the Rockies (NLR), a U.S. Department of Energy facility, have spent more than a decade working with NASA to build safer batteries for space travel. Their latest breakthrough just earned NASA's 2025 Invention of the Year award, which they shared with industry partner KULR Technology Group.
The winning invention is a tiny device called the internal short-circuit device, or ISC-D for short. It looks like a stack of three thin metal discs, and researchers can implant it inside a lithium-ion battery cell between layers where energy is stored. A thin layer of wax holds the metal pieces apart until researchers are ready to trigger a test.
"The ISC-D is similar to placing a wrench between the layers of a cell in a precise, repeatable, and controlled environment," said Matthew Keyser, NLR's senior energy storage engineer.
When the time comes to test, scientists warm the battery to 57 degrees Celsius — slightly cooler than a fresh cup of coffee — which melts the wax. The metal discs then touch, creating a short circuit that releases all the battery's energy as intense heat. Researchers can watch exactly what happens and use that information to design better battery systems.
Why go through all this trouble? Because real batteries sometimes fail due to microscopic defects that are impossible to see during manufacturing — a tiny speck of dust, for instance, could cause an internal short circuit. In outer space, a flaw like that could bring down an entire capsule and its crew. Traditional testing methods, like stabbing batteries with nails or crushing them, only show how cells react to damage from outside. The ISC-D lets researchers study what happens when problems start from within.
Eric Darcy, former battery technical discipline lead at NASA's Johnson Space Center, said the device has become essential for testing. "Nearly all battery designs for manned spacecraft applications have been verified to resist propagation of thermal runaway from cell to cell thanks to test campaigns using trigger cells with the ISC-D," he said. Thermal runaway is the technical term for what happens when one overheated battery cell causes its neighbors to overheat too, creating a dangerous chain reaction.
The technology isn't just for space. Understanding how batteries fail internally could help make the smartphones, electric cars, and power grids here on Earth safer too. As NASA continues planning longer missions to the moon and eventually Mars, these tiny trigger devices may help ensure the batteries keeping astronauts alive don't let them down.