Indicator of remaining energy in storage cell of implantable medical device
First Claim
1. A method comprising:
- drawing a substantially constant first current pulse from an energy storage cell during a first time period between a starting time and an ending time;
measuring a first change of a terminal voltage across the cell during the first time period, in which the measuring the first change of the terminal voltage comprises measuring a polarization angle; and
comparing the measured first change to first stored data to determine the energy remaining in the cell.
1 Assignment
0 Petitions
Accused Products
Abstract
A manganese dioxide (MnO2) or silver vanadium oxide (SVO) or other battery of an implantable medical device having a relatively flat quiescent battery voltage during a beginning portion of the battery'"'"'s useful life, makes it difficult to use quiescent battery voltage as an indicator of remaining battery energy during this portion of the battery life. A substantially constant load current pulse is drawn from the battery and a pair of loaded battery terminal voltage measurements is taken during this pulse. A difference between the voltage measurements is computed. This difference can be expressed as a rate of change, a slope, or a polarization angle, and can be used with stored data from similar batteries to determine remaining energy of the battery. A quiescent battery voltage can also be used in combination with this technique, and/or for distinguishing between different remaining energies corresponding to the same difference, slope, or polarization angle.
-
Citations
18 Claims
-
1. A method comprising:
-
drawing a substantially constant first current pulse from an energy storage cell during a first time period between a starting time and an ending time; measuring a first change of a terminal voltage across the cell during the first time period, in which the measuring the first change of the terminal voltage comprises measuring a polarization angle; and comparing the measured first change to first stored data to determine the energy remaining in the cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method comprising:
-
drawing a substantially constant first current pulse from an energy cell during a first time period; measuring a first change in a terminal voltage across the cell during the first time period; drawing a substantially constant second current pulse from the cell during a different, second time period; measuring a second change in the terminal voltage across the cell during the second time period, in which the measuring first and second changes in the terminal voltage comprises measuring a polarization angle; and comparing the measured second change to first stored data to determine an energy remaining in the cell, including comparing the first and second changes to distinguish between two different stored capacity values that correspond to a single change in the terminal voltage across the cell. - View Dependent Claims (13, 14, 15, 16, 17)
-
-
18. A system comprising:
-
means for drawing a substantially constant first current pulse from an energy storage cell during a first time period between a starting time and an ending time; means for measuring a first change of a terminal voltage across the cell during the first time period, in which the measuring the first change of the terminal voltage comprises measuring a polarization angle; and means for comparing the measured first change to first stored data to determine the energy remaining in the cell.
-
Specification