Patent ID: 7912546
Filing Date: 2011-03-22
Classification: A61N,G01R

Abstract:
1. An implantable medical device comprising: a hybrid battery comprising a combination of at least two electrode materials, a first of said electrode materials having better properties for high current pulsing than a second of said materials, and said second of said materials being a high energy density material; circuitry powered by said battery configured to interact with a living subject to administer electrical therapy to the subject; an apparatus that determines a replacement time of said battery by determining a base current that is drawn from the battery, and by drawing an electrical pulse of a predetermined duration and a predetermined amplitude from the battery, said pulse amplitude significantly exceeding said base current, automatically determining a difference between a first voltage measured between the battery terminals before emitting said pulse and a second voltage measured between the battery terminals at an end of the pulse, and automatically determining a replacement time for said battery from said voltage difference according to a predetermined criterion and triggering a battery replacement indicator when said time has been reached.