Lithium-ion battery diagnostic and prognostic techniques
AssigneeHoneywell International Inc.
InventorHarmohan N. Singh
Life of this patent
Estimating the term…
Abstract
Embodiments provide a method and a system for determining cell imbalance condition of a multi-cell battery including a plurality of cell strings. To determine a cell imbalance condition, a charge current is applied to the battery and is monitored during charging. The charging time for each cell string is determined based on the monitor of the charge current. A charge time difference of any two cell strings in the battery is used to determine the cell imbalance condition by comparing with a predetermined acceptable charge time difference for the cell strings.
Claims11
A method for determining cell imbalance of a battery comprising:
- applying a charge current to a battery comprising first and second cell strings;
- monitoring the battery charge current in the first and second cell strings;
- sensing a first sudden current reduction in the battery charge current;
- determining a first cell string charge time in the first cell string;
- sensing a second sudden current reduction in the battery charge current;
- determining a second cell string charge time in the second cell string;
- comparing the first cell string charge time to the second cell string charge time;
- determining a charge time difference between the first cell string charge time and the second cell string charge time
- determining that a cell imbalance is not present in the battery if the determined charge time difference is less than or equal to a predetermined acceptable charge time difference;
- and
- determining that a cell imbalance is present in the battery if the determined charge time difference is greater than a predetermined acceptable charge time difference.
A method for determining cell imbalance of a battery comprising:
- applying a charge current to a battery, wherein the battery comprises a plurality of cell strings;
- monitoring the battery charge current;
- counting a charge time for every cell of a first cell string of the plurality of cell strings based on sensing a first sudden reduction in the battery charge current, wherein the sudden current reduction indicates a charge completion of one of the first cell string;
- counting a charge time for every cell of a second cell string of the plurality of cell strings based on sensing a second sudden reduction in the battery charge current, wherein the sudden current reduction indicates a charge completion of one of the second cell string;
- determining a charge time difference between the first and second cell strings of the plurality of cell strings;
- and
- comparing the charge time difference between the first and second cell strings of the plurality of cell strings with a predetermined acceptable charge time difference for the plurality of cell strings of the battery, wherein a condition in which the charge time difference is greater than the predetermined acceptable charge time difference indicates a cell imbalance condition of the battery.
Dependencies are inferred from the claim text.