Description: West Coast Solutions (WCS) and the Georgia Institute of Technology (GT) have teamed to propose the Rechargeable Batteries for Improved Low-Temperature Performance based on Alloy Anodes Program. The proposed approach to achieving the required energy and temperature metrics in this program involves combining high energy lithium and sodium-ion battery components into full cells that to date have been used in isolation from each other at low temperatures. These materials and electrolytes have higher specific capacities than those used in commercial lithium-ion chemistries and/or have demonstrated impressive electrochemical performance at and below -40°C. Together, they show great promise for meeting metrics of high energy density at room temperature (> 300 Wh/kg) with the ability to cycle at extreme low temperatures (-80°C). The secondary thrust of the proposed effort is battery packaging, with a particular Phase I focus on thermal management given the inherent challenge of achieving a functioning cell at -80°C. Even with the projected improvements at low temperature obtained through the proposed lithium and sodium-ion combination, it will still be advantageous to limit operation at extremely cold temperatures to improve cycle life and to implement techniques to leverage self-heating to increase the core temperature off the lower limits. WCS has identified several promising technologies including variable conductance heat pipes (VCHP), thermal switches, and freeze-tolerant radiators. These and other thermal management technologies will be explored in a system context, along with the development of a notional BMS feature set, to identify the optimum battery system implementation approach for the developed cell technology.

Benefits: The development of a robust, high-performance secondary battery capable of extended operations for to -80°C is enabling for operations on Mars, other small planetary bodies, and the Earth's moon, all of which typically target -40°C, or colder. The combination of the advanced cold cell technology with the developed thermal management solution could potentially even make this research relevant for outer planet missions targeting -180°C. Commercial companies such as SpaceX, Blue Origin, Intuitive Machines, and many others have interest in lunar and small body exploration, so their battery needs are common with NASA's in regard to extreme cold temperature tolerance.