Primary batteries (single discharge batteries) are used in missions that require one-time use of electrical power for few minutes to several hours. Primary batteries have been used in planetary probes and sample return capsules (Stardust, Genesis, Deep Impact, Galileo), Mars Landers (MER), and Mars Rovers (Sojourner).
Primary batteries that are presently being used in various space missions are: a) Zn-AgO, b) Li- S02, c) Li-SOCb, and d) Li-CFx. Zn-AgO batteries have low specific energy (100-150 Whlkg) and short shelf life (6-12 months) and they are not attractive for future pace science missions. Zn-AgO batteries are fully developed and offer little opportunity for further improvemel!t.
Li-S02 and Li-SOCb batteries deliver moderate specific energy (100-250 Whlkg), can operate over a temperature range of -40°C to + 60°C, and have proven lifetimes of up to 10 years. The major limitations associated with these batteries are limited performance capabilities at temperatures lower than -40°C and voltage delay. These batteries are not attractive for missions that require operation below -40°C. Li-S02 batteries are fully developed, and offer very little opportunity for further improvement. Li-SOCb batteries on the other hand have potential for further improvement, particularly in the area of low temperature performance.
The Li-CFx battery has the highest specific energy of primary batteries and has a minimum voltage delay. The major limitations of the existing versions are very low specific power and limited operating temperature range. This system has substantial potential for further improvement, particularly in the areas of rate capability and low temperature performance.
