5 min read
If you've ever had your car start sluggishly, or not at all, on a particularly frigid winter morning, you know standard batteries do not like extreme cold. That's why NASA researchers are working to develop a battery that could function in the brutal cold of the Moon's South Pole, where nighttime temperatures plunge to minus 328 degrees Fahrenheit (minus 200 Celsius).
For future lunar operations, a battery will need to work immediately when warmed up and be able to power everything from an astronaut's emergency kit to a rover capable of exploring the Moon's darkest craters - all without posing a fire hazard.
A team of NASA researchers is working to make all that happen. The project is called Solid Power for Extreme Environment Adaptability and Resilience in Space (SPEARS), and it could provide NASA with an important tool to help power humanity's sustained presence on the Moon through the Artemis campaign.
"Batteries have become an important part of our lives here on Earth, which enable our laptops, cell phones, power tools, and even our vehicles," said Donald Dornbusch, principal investigator for SPEARS at NASA's Glenn Research Center in Cleveland, where the project is led. "We will need them on the Moon, too, and these batteries will be required to operate reliably and safely in this harsh environment. That's why we're working on this technology."
Traditional lithium-ion batteries like those in your cell phone and laptop have a critical weakness: they rely on liquid electrolytes. Cool a conventional battery to the Moon's nighttime temperatures, and that liquid would freeze, potentially damaging the battery. Heat it up too much - say, to daytime lunar temperatures of 212 F (100 C) - and it won't work until cooled. Expose the liquid to the vacuum of space, and it evaporates.
SPEARS batteries solve these problems by replacing the liquid electrolyte with a solid ceramic- or polymer-based material. This change could unlock several advantages. First and foremost, they could operate in the heat and extreme cold.
During recent thermal vacuum testing at NASA's Langley Research Center in Hampton, Virginia, small prototype battery cells operated well up to 176 F (80 C), down to minus 76 F (minus 60 C), and with slightly reduced performance down to minus 112 F (minus 80 C).
"We proved for the first time that these cells can work down to minus 80 degrees Celsius," said Yi Lin, SPEARS testing and research lead at NASA Langley.
Lin also said he's confident they can improve performance and maybe even expand that range in coming years.
The batteries need to remain reliable through exposure to the Moon's wild temperature swings between day and night. The thermal vacuum testing showed that after exposure to temperature extremes from 212 F (100 C) to minus 274 F (minus 170 C), SPEARS batteries don't sustain damage.
