A report describes an experimental study of the low-temperature electrical characteristics of commercial Li/MnO2, Li/CFx, Li/SO2, Li/SOCl2, and Li/BCX primary electrochemical cells. These high-energy-density cells are under consideration for use as lightweight, compact electric-power sources for scientific instruments in terrestrial polar regions and on Mars, where they could be called upon to operate at temperatures as low as 85 °C. The experiments, performed at temperatures down to - 100 °C, included steady-state current-vs.-voltage measurements during discharges with various increments of load resistance from 105 down to 10 Ω, complete discharge tests, and ac-impedance measurements.
This work was done by Frank Deligiannis, Harvey Frank, Evan Davies, and Ratnakumar Bugga of Caltech for NASA's Jet Propulsion Laboratory. NPO-20352
This Brief includes a Technical Support Package (TSP).
Lithuim-based primary cells for low-temperature operation
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Overview
The document is a NASA Technical Support Package detailing research on lithium-based primary cells designed for low-temperature operation, particularly for applications in extreme environments such as space missions and polar regions. The impetus for this research stems from the need for reliable electrochemical power sources that can function effectively at sub-zero temperatures, which is critical for missions like the Mars Microprobe on the 1998 Mars Surveyor Lander Mission.
The study evaluates five types of lithium primary batteries: Li-MnO2, Li-CFX, Li-SO2, Li-SOC12, and Li-BCX. These batteries were selected for their high energy density, compactness, and lightweight characteristics, making them suitable candidates for the demanding conditions of space exploration. The research includes performance screening tests, complete discharge tests, and internal impedance measurements to assess the batteries' capabilities at temperatures down to -100°C.
Key findings indicate that while the batteries generally maintain steady voltage under various loads, their performance can be significantly affected at very low temperatures and high current drains. For instance, a D-size Li-MnO2 cell can sustain a current of -200 mA at -75°C, while other cells have different operational limits at extreme temperatures. The document emphasizes the importance of understanding the performance-limiting mechanisms of these batteries at ultra-low temperatures, as there is limited existing literature on this topic.
The report also discusses the methodology used to generate steady-state current-potential curves at various low temperatures, providing quantitative data on the feasibility of using these batteries in specific applications. The results highlight the need to limit currents and temperatures during sustained operations to avoid excessive polarization of the cells.
Overall, this document serves as a comprehensive overview of the experimental program undertaken to evaluate lithium primary batteries for low-temperature applications, showcasing their potential for future space missions and other strategic applications. The findings contribute valuable insights into the development of reliable power sources capable of operating in extreme conditions, which is essential for advancing exploration efforts on Mars and beyond.
