BQ34Z100EVM: Inquiry Regarding Learned Status Not Updating to 5 on bq34z100EVM

Tool/software:

Dear TI Support Team,

I am encountering an issue where the Learned Status does not update from 4 to 5 during the learning cycle on the bq34z100EVM. Below are the details of the experimental setup and process:

A. Equipment:

• bq34z100EVM
• EV2400
• Single-cell PLB 26650-33A

B. Preparations:

1. Programmed ChemID: 4165
2. Calibrated voltage, current, and temperature

C. Learning Cycle Process:

1. Fully charged the single cell and rested it for a period of time
2. Enabled IT with IT_ENABLE
3. Used a loader to set CV discharge to 2500mV, then adjusted to 2000mV. Observed the log, and when the battery voltage was approximately 2006mV, removed the load to enter Relax mode
4. Entered Relax mode for 8 hours. Status at this time:
   • RUP_DIS = 0
   • VOK = 0
   • Learned Status = 4
5. Used a power supply to charge the battery at 3.65V (C/3). Observed that the taper current dropped below the set parameter of 33mA (based on cell spec). After several minutes, stopped charging. Status at this time:
   • FC = 1
   • Prepared to enter Relax mode
6. Entered Relax mode for 12 hours
7. Current status:
   • RUP_DIS = 0
   • VOK = 0
   • QEN = 1
   • REST = 1
   • Learned Status = 4

Despite following this process, the Learned Status remains at 4 and does not update to 5.

I suspect this might be due to not achieving 90% DOD (Depth of Discharge), which prevents Qmax from updating. However, I calculated the DOD using the logged QmaxDOD0 values:

• After discharge: 15980
• After charge: 1132
• Calculation: (15980 - 1132) / 16384 = 0.90625 = 90.625%

It appears that the 90% DOD requirement is met based on this calculation. Could you confirm if this calculation is correct? If the calculation is correct, could you advise why the Learned Status is not updating to 5 and how I might resolve this issue?

CHG_Full:

CHG_Relax:

DSG_to_Empty:

learning cycle log file:

IFR26650_33A_20241217.log

gg file:

IFR26650_1S1P_20241219.gg.csv

Thank you for your assistance.

Best regards,