Battery management system for extending service life of a battery
AssigneeInternational Business Machines Corporation
InventorsRichard J. Fishbune, Xing Li, Robert B. Schlak
Life of this patent
Estimating the term…
Abstract
Battery management systems and methods for optimizing and extending the service life of a battery generally include subjecting the battery to a test cycle that appropriately sets the state of charge for the battery to less than the nominal capacity of the battery, i.e., to less than 100% state of charge. The state of charge of other batteries in the system not being tested can be increased to insure that the system battery capacity is not degraded during the test cycle. Periodic testing of the battery and adjusting the state of charge maintains an optimal state of charge as the battery ages. Batteries that do not meet the required capacity can be readily identified and replaced on demand.
Claims20
A method for optimizing and extending a service life of a battery within a battery pack, the method comprising:
- determining an initial state of charge (SoC) of the battery based at least in part on a nominal capacity profile and an operational capacity requirement;
- determining a test voltage for the battery based on the initial SoC and a correction factor;
- setting the battery to the test voltage;
- discharging the battery at a rate, wherein the rate is determined by the operational capacity requirement for the battery;
- measuring a discharge voltage of the battery after discharging the battery;
- determining a new SoC based at least in part on the discharge voltage;
- determining an error value based on the new SoC and the correction factor;
- determining a corrected SoC based on combining the error value and the initial SoC;
- and
- charging the battery to a new voltage based at least in part on the corrected SoC.
The method of claim, 1, further comprising increasing SoC of other batteries in the battery pack prior to setting the battery to the test voltage.
A method of optimizing and extending a service life of a battery in a system, the method comprising:
- partially charging the battery to a set point state of charge (SoC);
- periodically testing the battery and adjusting the set point SoC, wherein a testing cycle comprises:
- increasing SoC set points of other batteries in the system to maintain a required capacity for the system during the test cycle;
- setting the battery being tested to a test battery voltage corresponding to an initial SoC set point and a correction factor;
- discharging the battery being tested at the required capacity;
- measuring the battery voltage after discharging the battery and determining a SoC at the measured battery voltage;
- determining an error value based on the SoC at the measured battery voltage and the correction factor;
- adjusting the initial SoC set point to a new set point SoC based on combining the error value and the initial SoC;
- and
- adjusting a voltage of the battery to the new SoC set point.
A battery management system for a battery, comprising
- a battery;
- and
- a controller circuit operable to:
- determine an initial state of charge (SoC) of the battery based at least in part on a nominal capacity profile;
- determine a test voltage for the battery based on the initial SoC and a correction factor;
- set the battery to the test voltage;
- discharge the battery at a rate, wherein the rate is determined by an operational capacity requirement for the battery;
- measure a discharge voltage of the battery after discharging the battery;
- determine a new SoC based at least in part on the discharge voltage;
- determine an error value based on the new SoC and the correction factor;
- determine a corrected SoC based on combining the error value and the initial state of charge;
- and
- charge the battery to a new voltage based at least in part on the corrected SoC.
Dependencies are inferred from the claim text.