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

Cherry Zhou

Part Number: BQ28Z610
Other Parts Discussed in Thread: GPCRB

Hi team,

Here's an issue from the customer may need your help:

When encountering abnormal conditions in practical application, Voltage V.S RSOC has a big drop and they 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 they try 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.rar 0576.gg file.rar

Could you help check this case? Thanks.

Best Regards,

Cherry

over 2 years ago

0 Wyatt Keller over 2 years ago

TI__Guru** 104695 points

Hello Cherry,

I think this is a duplicate thread: https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/1069239/bq28z610-data-of-soc

I will answer here since the data was posted here.

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.

Sincerely,

Wyatt Keller

0 Cherry Zhou over 2 years ago in reply to Wyatt Keller

TI__Mastermind 22235 points

Hi Wyatt,

Thanks for your help here!

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

https://e2echina.ti.com/support/power-management/f/power-management-forum/191813/bq27542-g1-at-0deg-chargeing-jump-soc-12-to-0/590821?tisearch=e2e-sitesearch&keymatch=BQ28Z610%25252525252520SOC%25252525252520JUMP#590821

Thanks and regards,

Cherry

0 Wyatt Keller over 2 years ago in reply to Cherry Zhou

TI__Guru** 104695 points

Hello Cherry,

Since the SOH is fluctuating I 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? I'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.

Sincerely,

Wyatt Keller

Because of the holidays, TI E2E™ design support forum responses will be delayed from Dec. 25 through Jan. 2. Thank you for your patience.

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