State of the art sealed NiCd button cells optimized for telecommunications use

The author reviews developments to upgrade the performance of NiCd button cells to meet the requirements of equipment designed for use in the 1990s, with special emphasis on improving the battery´s trickle charge and quick-charge facilities. It is concluded that requirements to enable portable equipment to be fully charged, within an 8 h working day, can now be achieved with a simple charger which can apply a 0.2 C charge to batteries regardless of their state of charge and without any prior conditioning. On the same basis, the need to recover batteries which are used in the standby mode more quickly than the four days previously possible for NiCd button cells, and 24 h required by NiCd sintered cells, can now be achieved by the inclusion of a timer to charge for 7 h at 0.2 C