Batteries: Unwanted memory spooks nickel-cadmium cells: New understanding of an undesirable phenomenon is the first step in avoiding it

It's been almost 80 years since the first nickel-cadmium cell was developed by Waldemar Jungner in Sweden. Since then, technical refinements and improved manufacturing techniques have made batteries based on this original design welcome in millions of portable electronic products, emergency lighting systems, and standby power applications. What little adverse publicity these batteries have encountered centers on “memory,” an effect where otherwise good cells temporarily lose rated capacity in a manner unrelated to normal aging/shelf-life considerations.