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BQ40Z50-R2: Application issues

Reed
Expert 2020 points
Part Number: BQ40Z50-R2
Other Parts Discussed in Thread: BQSTUDIO

Hi,

The battery meter chip model used is BQ40Z50-r2. The charge and discharge data of two sets of battery cells were captured through the Battery Management Studio upper computer and sent to the official website as required to obtain the chemical ID tool. The best chemical ID feedback was not found in the upper computer's chemical ID library, and even after updating the chemical ID library, there was still no corresponding ID. Attached is the recommended chemical ID package for me, TIID_csv report. zip, TIID_csv.zip is preparing to capture the charging and discharging data packet of the battery cells. Could you please help me confirm what the problem is,

TI_ID_csv.zipTI_ID_csv-report.zip

  • +1
    TI__Mastermind 37981 points

    Hello Reed,

    ChemID 5895 is showing up for me when I open BQStudio. Make sure to press the "Include chemistry IDs that do not support Turbo Mode 2".

    Regards,

    Nick Richards

  • 0 in reply to Adrian
    Expert 2020 points

    Nick, Thanks!

    The current chemical ID is 5895,

    Charging completed 2641mAh, repeated 3 times with consistent data.

    The attachment is the battery level meter configuration file TI_18650-Plus_V2.0_20240320.gsg.csv, as well as the data ls_test.csv captured by Battery Management Studio for battery discharge and charging.

    ls_test.csvTI_18650_Plus_V2.0_20240320.gg.csv

    Please help analyze it, thank you!

  • 0 in reply to Reed
    TI__Mastermind 37981 points

    Hey Reed,

    The log file results do not look bad. You can try running test with Load Select set to 1 to see if there is any greater improvement to gauging.

    Regards,

    Nick Richards

  • 0 in reply to Adrian
    Prodigy 190 points

    Hi:

    I followed the suggestion to set the load select to 1 and relearned it before conducting a charge discharge test. My designed capacity was 3000mAh. During the discharge process, I found that the battery SOC was 300-400mAh lower than the set cutoff voltage of 2700mV when it reached 0% FCC update. However, at this time, the discharge did not reach the cutoff voltage I set. When I continued to discharge to the cutoff voltage, I was able to release about 2900mAh of electricity. After the discharge was completed, I let it sit for about 1 hour and the full charge capacity was updated to around 2900mAh. After inserting a charger and fully charging, the FCC update was still 300-400mAh lower. May I ask if this situation is a configuration error? Attached are logs and Data memory data captured using Battery Management Studio. Please help me resolve this issue. Thank you!5895test_data.zip

  • 0 in reply to lan xin
    TI__Mastermind 37981 points

    Hey Ian,

    What ChemID are you using? How did you get the ChemID?

    Regards,

    Nick Richards

  • 0 in reply to Adrian
    Prodigy 190 points

    Hi Nick,

    I obtained the best matching ID 5895 using two batteries, following the chemical ID acquisition guide document on TI's official website.

    The attachment contains the guidance document for my reference, data on battery matching chemical ID, and feedback chemical ID reportchemistry_ID_data.zip

  • 0 in reply to lan xin
    TI__Mastermind 37981 points

    Hey Ian, 

    Thanks for sending over the data, please allow me some time to review it.

    Regards,

    Nick Richards

  • 0 in reply to Adrian
    TI__Mastermind 37981 points

    Hey Ian,

    I have some time to review all the data again. The chemID you are using looks good. I revisited the log file you sent before and I want you to try a new configuration for the gauge. You are discharging at a high rate relative to the full charge capacity of the battery. I believe the gauge during discharge is overestimating the full charge capacity because of the discharge rate paired with the high temperature seen towards the end of discharge which might be why you see a jump in FCC after discharge. Seeing this, I want you to run a new test with the same discharge and charge profile, but this time change load select to 6 and change User Rate-mA to 6000. Run the test 2 times and let me know if you see better results.

    Regards,

    Nick Richards

  • 0 in reply to Adrian
    Prodigy 190 points

    Hi Nick,

    Thank you for your suggestion, but I haven't conducted any testing yet. What I need to explain to you is that I am using drone products, not in environments with constant 6A loads. If modifying according to the suggestions can effectively solve my problem, is it suitable for situations with variable currents? I have checked the user manual of Bq40Z50-r2, which states that the load select is set to 4-6. If the fixed estimated value differs significantly from the actual load, it may lead to significant errors.

  • 0 in reply to lan xin
    TI__Mastermind 37981 points

    Hey Ian,

    Yes, you are correct that it is possible that it can cause significant errors. However, variable loads are very hard to gauge and usually our first recommendation for parameter changing for gauging this type of load is to set the user rate to the upper limit of the variable load. Variable load application takes much tuning and testing on their customer end.

    Regards,

    Nick Richards

  • 0 in reply to Adrian
    Prodigy 190 points

    Hi Nick，

    According to your suggestion, modify the load select to 6 and set the User Rate mA to 6000. The results of charging and discharging twice are consistent with before, but the full charge capacity is still below 300mAh~400mAh. Please refer to the attached data and battery specification sheet for any other unreasonable configuration items. Please provide other solutions.5895two_test.zip

  • 0 in reply to lan xin
    TI__Mastermind 37981 points

    Hey Ian,

    Can you run that test 2 more times (same discharge, charge, discharge, charge cycle). The gauge should hopefully learn the true Full Charge Capacity over time and running more cycles will help the gauge in the learning process. This is also important since we change the load select so the gauge now has a new basis for learning.

    Regards,

    Nick Richards