Patent ID: 6930468

Claim:
A method for powering an implantable medical device with a first electrochemical cell, the first cell comprising an alkali metal anode coupled to a cathode of a cathode active material activated with an electrolyte, comprising the steps of: a) discharging a second cell of a similar chemistry as the first cell to deliver a first pulse discharge of electrical current of significantly greater amplitude than that of a pre-pulse current or open circuit voltage immediately prior to the first pulse discharge; b) waiting a first time interval; c) discharging the second cell to deliver a second pulse discharge of electrical current of significantly greater amplitude than that of a pre-pulse current or open circuit voltage immediately prior to the second pulse discharge; d) deriving a first discharge curve from the first and second pulse discharges; e) discharging a third cell of a similar chemistry as the first cell to deliver a third pulse discharge of electrical current of significantly greater amplitude than that of a pre-pulse current or open circuit voltage immediately prior to the third pulse discharge; f) waiting a second time interval greater than the first time interval; g) discharging the third cell to deliver a fourth pulse discharge of electrical current of significantly greater amplitude than that of a pre-pulse current or open circuit voltage immediately prior to the fourth pulse discharge; h) deriving a second discharge curve from the third and fourth pulse discharges; i) taking a first voltage reading at a first predetermined point on the first discharge curve to determine a first loaded voltage reading; j) synchronizing a first depth-of-discharge (DOD) of the first loaded voltage reading with the second discharge curve to determine a corresponding second DOD of the second loaded voltage reading of the third cell; k) subtracting the second loaded voltage reading from the first loaded voltage reading and then dividing by the first loaded voltage reading to determine a percent change; and l) pulse discharging the first cell powering the implantable medical device at least about once every 90 days and then upon the percent change exceeding about 3% of the first loaded voltage reading, discharging the first cell to deliver periodic current pulse discharges of significantly greater amplitude than that of a pre-pulse current or open circuit voltage immediately prior to the periodic current pulse discharges at intervals less than 90 days.