Lithium Alloy-Thionyl Chloride Cells: Performance and Safety Aspects

The maximum short-circuit current (SCC) of lithium alloy-thionyl chloride AA-cells was reduced by a factor of 20–50 in comparison with that of regular lithium cells. The maximum SCC of spirally wound D-size cells having a lithium alloy as an anode was reduced by a factor of 2–3. This was done by a pretreatment which includes discharge for 4–12 mA-hr-cm-2(of anode) followed by storage at room temperature or 72°C for 3–14 days depending on the alloy type. It was concluded that as a result of this pretreatment an alloy-rich barrier layer is formed on the entire surface of the anode (beneath the LiCl passivating layer). Such a barrier layer may be formed in all the primary and secondary ambient temperature cells with lithium alloy anode. During intermittent use of any type of lithium alloy cells (not only Li/SOCl2 cells) over long periods of time, an alloy barrier layer can be formed that, if allowed to grow in an uncontrolled manner, can decrease the rate capability of the cells below a useful value.