Patent Number: 6,167,309

Title: Method for monitoring end of life for battery

Abstract: A system is described which has a battery, a device which is powered by the battery in an episodic manner, and a charge storage capacitor, the system having a device(s) attached to the charge storage capacitor which is capable of: g) reading the rate of charge storage or h) measuring both time and charge stored or added to the charge storage capacitor so that a rate of charge storage may be calculated. The use of this system allows for easy estimation of the estimated replacement time for the battery, particularly for a lithium battery in a pacing device. A process for estimating a level of energy depletion in the system may comprise; d) finding a relatively quiescent period in powering of the device in the episodic manner, e) determining a rate of charging in the storage capacitor during the quiescent period, and f) correlating the rate of charging in the storage capacitor to a value of internal resistance in the battery through a comparison with known relationships for the battery and rate of charging to determine a value for the internal resistance of the battery.

Inventors: Lyden; Michael J. (Shoreview, MN)

Assignee: Cardiac Pacemakers, Inc.

International Classification: A61N 1/362 (20060101); A61N 1/37 (20060101); G01R 31/36 (20060101); A61N 001/37 ()

Expiration Date: 12/26/2017