BQ40Z50-R2: SOH change un-normal

Yuxi Liu(Tony)

Part Number: BQ40Z50-R2
Other Parts Discussed in Thread: BQ40Z50

Tool/software:

Hi TIer

My customer have a battery pack of 21700 cell (4S1P), during the use of the SOH value has become very low, recharge and discharge will resume normal.

Use the scenario description:
1, the battery transportation process uses shutdown mode. Plug-in active at user.
2, normal use at the user, about 1 to 2 months found SOH abnormalities (70%, 80%), These batteries are new and the customer has confirmed that the cells are good. The user's operating state is battery-only at night, and battery-powered and acdc-powered during the day.

Can you help analyze why SOH falls? How we should avoid it.

We got the abnormal chip and read the registers as shown in the figure:

2 months ago

0 Yuxi Liu(Tony) 2 months ago

TI__Expert 3090 points

Hi TIer

Could you help me see this case.

Thank you very much.

0 Anthony 2 months ago in reply to Yuxi Liu(Tony)

TI__Mastermind 28450 points

Hi Tony,

Can you please provide the following files:

- The .gg file of the current gauge settings.

- A log file depicting the time where the abnormal SOH is seen and another when the SOH is normal.

Can you also give more information on what the typical discharge load is for this device?

Regards,

Anthony

0 Yuxi Liu(Tony) 2 months ago in reply to Anthony

TI__Expert 3090 points

Hi Anthony

I got the gg file. Which battery SOH is 85%. We don't have log file.

For the load , which is ultrasound scanner, 2A peak current. Customer already test the behavior of SOH in the peak discharge state. It looks good.

SOH change is random happen. So we need some debug suggestion.

Thank you for your support.

89FAIL1504008241223A03.gg.csv

0 Yuxi Liu(Tony) 2 months ago in reply to Yuxi Liu(Tony)

TI__Expert 3090 points

Hi Anthony

Our company currently using the BQ40Z50 chip, the battery currently shows an abnormally low SOH, re-discharge and recharge after normal. Currently trying to find the root cause of low SOH.

Update the load condition.

1, Battery is 21700 , 4S1P cells, 14.4V 4.7Ah
2, general about 4A load
3, when shutting down, 550uA left current.
4, work status2, 5mA current.

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BQ40Z50-R2: SOH change un-normal