Safety considerations of lithium-thionyl chloride cells

The use of spirally wound lithium-thionyl chloride (Li-SOCl2) cells is currently limited because of their hazardous behavior. Safety hazards have ranged from mild venting of toxic materials to violent explosions and fires. These incidents may be related to both user- and manufacturer-induced causes. Many explanations have been offered to explain the unsafe behavior of the cells under operating and abuse conditions. Explanations fall into two categories: (1) thermal mechanisms, and (2) chemical mechanisms. However, it is quite difficult to separate the two. Both may be responsible for cell venting or explosion. Some safety problems encountered with these cells also may be due to design deficiencies and ineffective quality control during cell fabrication. A well-coordinated basic and applied research program is needed to develop safe Li-SOCl2 cells. Recommendations include: (1) learnig more about Li-SOL2 cell chemistry; (2) modeling cell and battery behavior; (3) optimizing cell design for safety and performance, (4) implementing quality control procedures; and (5) educating users.