NASA Prototype Batteries Work to Minus 80°C, Survive Minus 170°C

NASA's SPEARS solid-state prototype cells — experimental batteries with no liquid inside — kept working down to minus 80 degrees Celsius in thermal vacuum testing at Langley, which simulates space conditions. Performance dipped slightly below minus 60. The same cells were undamaged from 100 degrees down to minus 170, where they survive but cannot operate.