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Original question:

BQ34Z100-G1: BQ34Z100-G1 SOC jump during after 2 months shipping

BQ34Z100-G1: The SOC jumps after 48 hours of rest, with a probability of 100%. LiFePO4 cell, 16S4P, bq34z100-G1.

jmyang
Expert 1186 points
Part Number: BQ34Z100-G1
Other Parts Discussed in Thread: BQ34Z100-R2,

Masters of TI,

I have a battery product ready for mass production, and now there is a serious problem.

The SOC changes after 48 hours of battery rest. For example, the following data shows that the SOC changes from 30% to 56%.

The battery is 16S4P and LiFePO4.

The chemical ID of the cell is sent to Texas, USA. Normal charging and discharging, SOC is normal.

However, after standing for 48 hours, the SOC of each battery jumps.

Is there any way to solve this problem?

IDU100GA-C40-34z100-0-16-4138-10bei-0.125mR-R00-2022-11-11.gg.csv

  • 0
    TI__Guru 57697 points

    First thing to check is calibration, especially current calibration

    Second if the correct chemistry is programmed as per GPC match report

  • 0 in reply to Shirish
    Intellectual 850 points

    Hello Shirish:

    Similar issue as we reported before. Do you think BQ34Z100-R2 may help on this problem?

    Thanks.

    Chen

  • 0 in reply to Chen Jia
    TI__Guru 57697 points

    I thought that was traced to using a sense resistor that was below 5mOhms which is not supported. Correct me if i mixed this up with another case.

  • 0 in reply to Shirish
    Intellectual 850 points

    Hello Shirish:

    Thanks for your prompt reply. 

    In the BQ34Z100-G1 spec, it stated 5-20mohms as "typical", so these are not the absolute limit, right? Also I noticed, in BQ34Z100-R2 spec, this typical value range is removed. Does this mean -R2 supports wider Rsense range than -G1?

    Thanks.

    Chen

  • 0 in reply to Chen Jia
    TI__Guru 57697 points

    BQ34Z100-R2 does not support a wider range of Rsense.

    The typical values are the values that are expected to work in the recommended applications. A value in the middle of this range would be ideal. Higher values will provide more accuracy and lower values will result in less accurracy.

    The typical numbers are specified with a max of 4x change.

    1mOhm is 5x lower than the typical minimum, so I would not expect it to work without additional adjustments/workarounds.