Excess pressure protection for primary cells - with fuse link enclosed in plastics housing

摘要

Gastight primary cell is fitted with a fuse link between a terminal and an electrode lead. The fuse wire is embedded at both ends in a plastic lid which is sealed to a cup-shaped plastic housing. The solder of the link pref has a melting temp of 80-140 deg C. Suitable plastic materials for lithium-SO2 cells are ethylene propylene, PTFE, neoprene and silicone rubber. Those for Ni-Cd cells must be resistant to caustic potash solution. This is a reliable protection against any excessive pressure build-up in the cell, when an external short-circuit, too high a current discharge or excessive charging should occur.