SLUUB65B May 2015 – December 2022
RELAXATION mode is entered either from CHARGE mode or DISCHARGE mode based on the relationship between AverageCurrent() and Quit Current. Quit Current sets a current threshold to determine when the fuel gauge goes into RELAXATION mode from CHARGE or DISCHARGE mode. Either of the following criteria must be met to enter RELAXATION mode:
During RELAXATION mode, FLAGS[DSG] bit is set.
The Chg Relax Time is used in the function to determine when to go into RELAXATION mode after charge current ceases. When AverageCurrent() is greater than Quit Current and then goes within (±)Quit Current, the Chg Relax Time timer is initiated. If the current stays within (±)Quit Current until the Chg Relax Time timer expires, then the fuel gauge goes into RELAXATION mode.
The Dsg Relax Time is used in the function to determine when to go into RELAXATION mode after discharge current ceases. When AverageCurrent() is less than (–)Quit Current and then goes within (±)Quit Current, the Dsg Relax Time timer is initiated. If the current stays within (±)Quit Current until the Dsg Relax Time timer expires, then the fuel gauge goes into RELAXATION mode.
After 30 minutes in RELAXATION mode, the fuel gauge starts checking if the dV/dt < 1 μV/s requirement for OCV readings is satisfied. When the battery relaxes sufficiently to satisfy this criterion, the fuel gauge takes an OCV reading for updating Qmax. These updates are used by the Impedance Track algorithm.
It is critical that the battery voltage be relaxed during OCV readings to get the most accurate results. The quit current threshold must not be higher than Design Capacity/20 when attempting to go into RELAXATION mode; however, it should not be so low as to prevent going into RELAXATION mode due to noise. The current threshold that the Quit Current parameter sets should always be less than the magnitude of the current threshold the Chg Current Threshold sets and less than the magnitude of the current threshold the Dsg Current Threshold sets.
Subclass ID | Subclass | Offset | Name | Data Type | Value | Unit | ||
---|---|---|---|---|---|---|---|---|
Min | Max | Default | ||||||
81 | Current Thresholds | 4 | Quit Current | I2 | 0 | 1000 | 40 | mA |
6 | Dsg Relax Time | U2 | 0 | 65535 | 60 | s | ||
8 | Chg Relax Time | U1 | 0 | 255 | 60 | s |