Voltage delay in Li/SOCl2 cells for artillery applications at -35°C

Two active Li/SOCl₂ cells for use in artillery-fired atomic projectiles are being developed. Voltage delay is the primary mode of electrochemical failure in these cells at -35°C. To minimize this anode polarization, the anode passivation is inhibited by adding chloromethyl chlorosulfate (CMCS) to the sulfur dioxide complex of lithium tetrachloroaluminate (LiAlCl₄-SO₂) in the cell electrolyte. One battery powers the telemetry system (TM battery) and the other powers a projectile event timer circuit (PET battery). The authors utilize the PET battery and PET load profile to demonstrate the effect of electrolyte additives on anode passive film growth and associated voltage delay. Similar effects were also observed in the TM battery. A limited number of PET prototypes were available for this study. Therefore, several tests were performed in hermetically sealed prismatic laboratory test cells which were constructed using the same electrochemical components which are used in the PET cells