Tracking fading battery capacity in a plugged-in portable electronic device
First Claim
1. A method for estimating a capacity of a battery in a portable electronic device, comprising:
- electrically coupling a portable electronic device to a power source;
charging, using the power source, a battery of the portable electronic device to a first state of charge, the first state of charge being above a threshold state of charge;
performing a first open-circuit voltage measurement on the battery while the battery rests at the first state of charge;
discharging the battery, while the portable electronic device remains electrically coupled to the power source, towards a second state of charge that is above the threshold state of charge;
monitoring a current through the battery while discharging the battery towards the second state of charge, the monitored current representing a net change in charge for the battery;
performing a second open-circuit voltage measurement on the battery while the battery rests at the second state of charge;
estimating a capacity of the battery based on the first open-circuit voltage measurement, the second open-circuit voltage measurement, and the net change in charge of the battery; and
displaying the estimate.
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Abstract
A system for tracking the capacity of a battery in a portable electronic device is described. While plugged in-to a power adapter, the system measures a first open-circuit voltage for the battery while the battery rests at a first state of charge. Next, the system causes the battery to transition to a second state of charge. During the transition, the system integrates a current through the battery to determine a net change in charge. Next, the system measures a second open-circuit voltage while the battery rests at the second state of charge. Finally, the system estimates a capacity for the battery based on the first and second open-circuit voltages and the net change in charge. This capacity measurement is repeated and the multiple results are fitted to a line. The slope of fitted line is used to estimate how the battery capacity has faded since last measured using traditional techniques.
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Citations
21 Claims
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1. A method for estimating a capacity of a battery in a portable electronic device, comprising:
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electrically coupling a portable electronic device to a power source; charging, using the power source, a battery of the portable electronic device to a first state of charge, the first state of charge being above a threshold state of charge; performing a first open-circuit voltage measurement on the battery while the battery rests at the first state of charge; discharging the battery, while the portable electronic device remains electrically coupled to the power source, towards a second state of charge that is above the threshold state of charge; monitoring a current through the battery while discharging the battery towards the second state of charge, the monitored current representing a net change in charge for the battery; performing a second open-circuit voltage measurement on the battery while the battery rests at the second state of charge; estimating a capacity of the battery based on the first open-circuit voltage measurement, the second open-circuit voltage measurement, and the net change in charge of the battery; and displaying the estimate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A portable electronic device, comprising:
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a connector configured to electrically couple to an external power source; a battery; a display unit; and a controller, operatively coupled to the connector, the battery and the display unit, and configured to; charge the battery using the external power source through the connector to a first state of charge, the first state of charge being above a threshold state of charge, perform a first open-circuit voltage measurement on the battery while the battery rests at the first state of charge, discharge the battery, while the portable electronic device remains electrically coupled to the power source, towards a second state of charge, the second state of charge being above the threshold state of charge, monitor a current through the battery during discharge, the monitored current representing a net change in charge for the battery, perform a second open-circuit voltage measurement on the battery while the battery rests at the second state of charge, estimate a capacity of the battery based on the first open-circuit voltage measurement, the second open-circuit voltage measurement and the net change in charge of the battery, and display the estimate on the display unit. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A system in a portable electronic device, comprising:
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a controller for a portable electronic device configured to, electrically couple the portable electronic device to a power source; charge, using the power source, a battery of the portable electronic device to a first state of charge, the first state of charge being above a threshold state of charge; perform a first open-circuit voltage measurement on the battery while the battery rests at the first state of charge; discharge the battery, while the portable electronic device remains electrically coupled to the power source, towards a second state of charge that is above the threshold state of charge; monitor a current through the battery during discharge towards the second state of charge, the monitored current representing a net change in charge for the battery; perform a second open-circuit voltage measurement on the battery while the battery rests at the second state of charge; estimate the capacity of the battery based on the first open-circuit voltage measurement, the second open-circuit voltage measurement and the net change in charge for the battery; and display the estimate. - View Dependent Claims (18, 19, 20, 21)
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Specification