BQ28Z610: Battery RSOC / SOH jump at the -10℃ (battery have GPCRB )

Dear TI Expert:
When encountering abnormal conditions in practical application, Voltage V.S RSOC has a big drop and we also see the SOH is float.
(EX: @-10℃ the Voltage=4.2V to 3.6V, RSOC=100% to 1%, SOH=100% to 25% )

The same question was asked before, and the reply asked me to use the GPCRB method to correct

The reference URL is as follows:
e2echina.ti.com/…/bq27542-g1-at-0deg-charging-jump-soc-12-to-0

Pack information:
CELL NCR18650BD 1S3P , GG chemistry ID 2072
Test conditions : @ -10℃ discharge 440mA / 30sec & relax 60sec, cut off SOC=0% or Voltage <3.0V

2022-01-27_01-RMA_ DISCHARGE.log.rar0576.gg file.rar

Cherry Zhou：

Hi we've got the issue and escalated to e2e, please expect the response. Thanks!

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Cherry Zhou：

Hi,

https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1069239/bq28z610-data-of-soc

Above is the thread may is duplicate.

It looks like the most dynamic parameter that could affect the SOH in this way would be the delta voltage, since you used a pulsed load we calculate the delta voltage and add it into the terminate voltage so we can predict a better runtime.

You can disable this function by setting the min delta voltage to a negative value. This may lead to other gauging issues, but it will let us confirm that the delta voltage is causing the SOH jumps.

Thanks.

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tzlu yeh：

hi Sir,

Can you provide suggestions under this application at present? Is there any need to modify other parameters?This case is GPCRB compensation according to the previous suggestion, why does this phenomenon still occur

e2echina.ti.com/…/590821

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Cherry Zhou：

Hi,

Since the SOH is fluctuating we don't believe it is related to the Rb tweak (GPCRB tool)

We use room temperature for the FCC SOH calculation, so it will not matter what the Rb values are for SOH. The only contributing factors are the Qmax and the Ra table that could be causing issues. Can you setup logging to export the .gg file during your testing? We'd like to review how the Ra table is updating during the test.

To setup the .gg logging, go to the data memory tab and then click auto export on the top right bar. Do this along with the regular logging.

Thanks.