Miniature Secondary Electrochemical Cell With Current Collector Design To Improve Open Circuit Voltage

A miniature electrochemical cell of a secondary chemistry having a total volume that is less than 0.5 cc is described. Before the present invention, miniature secondary electrochemical cells have been known to experience undesirable open circuit voltage discharge during their initial 21-day aging period. It is believed that electrolyte permeating through the cathode active material and an intermediate carbonaceous coating contacting the titanium base plate of the casing is the source of the undesirable discharge. To ameliorate this, aluminum is contacted to the inner surface of the base plate inside the casing. While aluminum is resistant to the corrosion reaction that is believed to be the mechanism for degraded open circuit voltage in miniature secondary electrochemical cells containing lithium, it is not biocompatible. This means that titanium is still a preferred material for the casing parts including the base plate that might be exposed to body fluids, and the like.