South 8 Technologies has signed a letter of intent with UK-based Arctic Research and Development to supply lithium-ion battery cells for extreme cold environments. The agreement covers South 8's ARCTIC AE35 cells for BB-2590 military battery systems and establishes a framework for broader collaboration. ARD is building prototypes integrating South 8 cells into BB-2590 systems, which power communications and mission-critical military equipment. The company is also developing extreme-cold battery solutions for unmanned aircraft systems and plans field demonstrations in Alaska and Norway. South 8's cells use proprietary liquefied gas electrolyte technology, enabling operation at temperatures down to −60°C. The San Diego-based manufacturer recently began volume production, with annual capacity expected to reach 5 MWh in 2027.