Dynamic rechargeable battery capacity monitor
AssigneeTexas Instruments Incorporated
InventorsFalong Li, Sihua Wen
Life of this patent
Estimating the term…
Abstract
A method for dynamically monitoring a capacity of a battery includes estimating a first voltage threshold of the battery that is being discharged, wherein the first voltage threshold corresponds to a low capacity of the battery, and measuring a present voltage and a present current of the discharging battery. The method further includes re-scaling the present current based on the estimated first voltage threshold and the measured present voltage of the discharging battery, and calculating, based on re-scaling the measured present current, the battery's capacity before the present voltage level decreases below the first voltage threshold.
Claims18
A method for dynamically monitoring a capacity of a rechargeable battery, the rechargeable battery having a discontinuity in a state of charge (SOC) determination during discharge of the battery as the SOC approaches an end of discharge voltage (EDV) of the rechargeable battery, the method comprising:
- determining a first voltage threshold of the battery that is being discharged, wherein the first voltage threshold corresponds to a low capacity of the battery;
- measuring a present voltage and a present current of the discharging battery;
- re-scaling the present current based on the determined first voltage threshold and the measured present voltage of the discharging battery;
- and
- determining, based on re-scaling the measured present current, the battery's capacity before the present voltage level decreases below the first voltage threshold;
- and
- alerting a user of a rechargeable battery—powered electronic circuit of the time to end of discharge voltage (EDV) for the battery.
An electronic apparatus operable from and coupleable to a rechargeable battery, the rechargeable battery having a discontinuity in a state of charge (SOC) determination during discharge of the battery as the SOC approaches an end of discharge voltage (EDV) of the rechargeable battery, the apparatus comprising:
- an alert device alerting a user of the apparatus of time to end of discharge voltage (EDV) for the battery;
- a measurement circuit coupleable to the battery and configured to measure voltage and current levels of the battery at first periodic intervals and to save the measured voltage and current levels in a storage unit;
- and
- an electronic circuit coupled to the measurement unit and configured to:
- generate a first voltage threshold of the battery at each periodic interval, wherein the first voltage threshold corresponds to a low capacity of the battery;
- compare a present voltage level with a second voltage threshold, and compare a difference value between the present voltage level and the first voltage threshold with a third voltage threshold;
- if the present voltage level is less than the second voltage threshold and the difference value is less than the third voltage threshold, determine a voltage dropping rate of the battery;
- based on the determined voltage dropping rate of the battery, determine an amount of time to reach end of discharge voltage for the battery from the present voltage level to the first threshold voltage;
- and
- based on the determined amount of time, compute a scale factor to re-scale a present current level;
- determine a re-scaled state of the battery's capacity based on the determined scale factor;
- and
- activate the alert device alerting the user of the apparatus of the end of discharge voltage (EDV).
A method for operating a rechargeable battery-powered electronic circuit, the rechargeable battery having a discontinuity in a state of charge (SOC) determination during discharge of the battery as the SOC approaches an end of discharge voltage (EDV) of the rechargeable battery, the method comprising:
- measuring voltage and current levels of the rechargeable battery at an interval;
- generating a first voltage threshold of the rechargeable battery at the interval, wherein the first voltage threshold corresponds to a low capacity of the rechargeable battery;
- comparing a measured voltage level with a second voltage threshold, and a comparing a difference value between the measured voltage level and the first voltage threshold with a third voltage threshold;
- determining if both the measured voltage level is less than the second voltage threshold and the difference value is less than the third voltage threshold, calculating a voltage dropping rate of the demand rechargeable battery based on previously measured voltages;
- based on the voltage dropping rate of the rechargeable battery, determining an amount of time to discharge the rechargeable battery from the present voltage level to the first threshold voltage;
- based on the computed amount of time, determining a scale factor to re-scale a measured current level so as to determine a re-scaled state of the rechargeable battery's capacity whereby the rechargeable battery's capacity is determined not to be below a level where proper operation of the electronic circuit can be guaranteed;
- and
- alerting a user of the rechargeable battery—powered electronic circuit of of the time to end of discharge voltage (EDV) for the battery.
Dependencies are inferred from the claim text.