TRACKING FADING BATTERY CAPACITY IN A PLUGGED-IN PORTABLE ELECTRONIC DEVICE

摘要

A system for tracking the capacity of a battery in a portable electronic device is described. While the portable electronic device remains plugged in to a power adapter, the system estimates the capacity of the battery by performing the following operations. 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. While the battery transitions to the second state of charge, the system integrates a current through the battery to determine a net change in charge for the battery. Next, the system measures a second open-circuit voltage for the battery while the battery rests at the second state of charge. Finally, the system estimates a capacity for the battery based on the first open-circuit voltage, the second open-circuit voltage and the net change in charge. This capacity measurement is repeated and the multiple results are fit to a line. The slope of fitted line is then used to estimate how the true battery capacity has faded since last measured using traditional methods that require the battery to be rested at a low state of charge.

主权项

1. A method for tracking a capacity of a battery in a portable electronic device, comprising:
while the portable electronic device remains plugged in to a power adapter that provides electrical power from a wall outlet, estimating the capacity of the battery by,
performing a first open-circuit voltage measurement on the battery while the battery rests at a first state of charge,causing the battery to transition to a second state of charge while the portable electronic device remains plugged in to the power adapter,while the battery is transitioning to the second state of charge, monitoring a current through the battery to determine 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, andcalculating the estimate for 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.