Page 415 - Lindens Handbook of Batteries

14.80 PriMAry BATTerieS

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0 500 1,000 1,500 2,000 2,500 3,000
Capacity, mAh
FIGURE 14.81 improvement in AA high rate performance on ANSi DSC test:
1A continuous test to 1.0 V.

of the cell or battery device designs. Service life is reduced as the discharge temperature is lowered
below room temperature, though the performance of the Li/FeS battery is affected much less by low
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temperature than are aqueous systems.
Effects of Current-Limiting Devices. Some current-limiting devices, such as thermal fuses and
PTCs, are designed to respond to high temperatures. Both the ambient temperature and internal cell
heating can affect these devices, so any of the following factors may play a role:
Surrounding air temperature
Thermal insulating properties of battery container
Heat generated by equipment components during use
Cumulative heating effects of multicell batteries
Discharge rates and durations
Frequency and duration of rest periods
it may be necessary to consult the manufacturer or conduct testing to determine limitations in spe-
cific applications.
Impedance. AC impedance is an electrical characteristic that is frequently used as an indicator of
performance for aqueous batteries. The correlation is only poor at best with Li/FeS batteries. There
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is a protective film that forms on the surface of the lithium anode. This film is an important factor in
the excellent shelf life of the Li/FeS cell. As the cell ages, this protective film increases with age.
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As the film increases, the impedance does as well. However, this film is easily disrupted when the
battery is put on load, making impedance inappropriate as an indicator of expected Li/FeS battery
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performance, especially after storage.
Storage Temperature. Storage at high temperature will reduce the service life of Li/FeS batteries,
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as it will with other systems. However, because of the very low levels of impurities in the materials
used and the high degree of seal effectiveness required in lithium batteries, service maintenance of
Li/FeS batteries after high-temperature storage is better than expected with aqueous systems. The
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typical storage temperature range of Li/FeS batteries is -40 to 60°C. Accelerated storage tests at
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