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BQ40Z80: Chem id Identification fails - How to send cells to TI

Ivan Petrusevski
Prodigy 80 points
Part Number: BQ40Z80
Other Parts Discussed in Thread: BQ28Z610, BQ78Z100, GPCCHEM

Hello,

We were trying to get the Chem ID for the Amicell LiPo 6S battery and did not succeeded. We uploaded data acquired as in documentation several times and every time we got 15% mismatch (error). We have also tried with Tatto LiPo 6S battery and we got matching under 3%. Therefore I assume that there is no matching battery/cell data in TI database.

Can you please tell me what is the procedure of sending the cells to TI in order to get Chem ID? Only info we found regarding this is in the Application report "How to Complete a Successful Learning Cycle for the bq28z610/bq78z100" -> "If there is no match, then the cells have to be sent to TI for characterization and chem id generation."

Thank you.

  • 0
    TI__Guru** 105590 points

    Hello Ivan,

    By following the guide you should be able to find a near match, 15% is very high because we have hundreds of cells characterized.

    To get a new chem ID the process can take several months, is this something you would still be interested in? I will need to contact our chem ID tech for more info about the process for you.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 80 points

    Hi Wyatt,

    Thank you on your reply. Before we decide to go to the procedure of sending the battery to TI, we would like to try to find out if TI has similar battery in the database. Currently I can not say which chemical is exactly inside the battery, but what I know is that is a LiPo 6S battery with Min/Cutoff voltage 16.5V (2.75V per cell) and Max voltage is 25.8V (4.3V per cell). Those values are defined by the battery producer.

    Do you know if there is a similar battery in TI database at least regarding those voltages?

    Thank you,

    Ivan Petrusevski

  • 0 in reply to Ivan Petrusevski
    TI__Guru** 105590 points

    Hello Ivan,

    When we match the chemistry IDs to a battery it mostly matches the OCV curve of the battery with the log you submitted so it wouldn't be possible to find a match without the OCV information during a discharge.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 80 points

    Hi Wyatt,

    In that case TI definitely does not have any similar battery in the database, since we already did several cycles and data submissions and gained 15% mismatch every time.

    Can you please contact your chem ID tech in order to find out what is exactly the procedure for the process of getting a chem ID for our battery.

    Best regards,

    Ivan Petrusevski 

  • 0 in reply to Ivan Petrusevski
    TI__Guru** 105590 points

    Hello Ivan,

    Usually this is done through your local area's FAE, they would put in a request form for you.

    From the chemistry ID tech:

    You need to use the charge voltage of the cell on the specification, not the pack charge voltage divided by the number of cells. A cutoff of 2.75V is also strange, it is usually at 2.5V or 3V which could cause a mismatch of chemistry IDs.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 80 points

    Hello Wyatt,

    We did a few more tests and tries to get a valid match but without any success. The best result is 15% for this battery. I just want to emphasize that there is nothing wrong with the setup or the procedure we do, because we got for an other battery type less than 3% mismatch.

    I guess the only solution here is to send the battery to TI. Can you please give me a contact of local area's FAE for Brooklyn New York. If you need any additional info from my side, please contact me.

    Best regards,

    Ivan Petrusevski  

  • 0 in reply to Ivan Petrusevski
    TI__Guru** 105590 points

    Hello Ivan,

    Can you share the data log and GPCCHEM report so we can take a look? Usually there is a match under 3% so it is strange that it is 15%.

    You should be able to contact an office closest to you from this site: www.ti.com/.../contact-us.html

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 80 points

    Hi, The requester data are attached.

    Cheers,

    Ivan Petrusevski

    Fullscreen 7587.GPC_report.txt Download 
    Chemistry ID selection tool, rev=2.5		
		
Configuration used in present fit:		
ProcessingType=2		
NumCellSeries=6		
ElapsedTimeColumn=0		
VoltageColumn=1		
TemperatureColumn=2		
CurrentColumn=3		
		
Best chemical ID : 2502	Best chemical ID max. deviation, % : 16.02	
		
		
		
Summary of all IDs with max. DOD deviation below 3%		
		
Chem ID	max DOD error, %	Max R deviation, ratio
0	0	0
		
Accuracy Error: Deviation is so high that it is most likely due to anomaly in the data. Please check that data files have recomended format, units and test schedule		
		
		
Selection of best generic ID for ROM based devices like bq274xx		
		
		
Device / Family #1		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
354	bq27411-G1C: 4.35V LiCoO2	29.45
3142	bq27421-G1D: 4.4V LiCoO2	31.3
128	bq27421-G1A: 4.2V LiCoO2	100
312	bq27421-G1B: 4.3V LiCoO2	100.88
Best generic ID 354		
Warning: Generic ID Deviation is so high that it is most likely due to anomaly in the data. Please check that data files have recomended format, units and test schedule		
		
		
Device / Family #2		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
354	bq27621:  (ALT_CHEM2) 4.35V LiCoO2	29.45
1210	bq27621:  (ALT_CHEM1) 4.3V LiCoO2	35.82
1202	bq27621: (default) 4.2V LiCoO2	99.34
Best generic ID 354		
Warning: Generic ID Deviation is so high that it is most likely due to anomaly in the data. Please check that data files have recomended format, units and test schedule		
		
		
Device / Family #3		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
3230	bq27426: (default) 4.35V LiCoO2	29.11
3142	bq27426: (ALT-CHEM2) 4.4V LiCoO2	31.3
1202	bq27426: (ALT_CHEM1) 4.2V LiCoO2	99.34
Best generic ID 3230		
Warning: Generic ID Deviation is so high that it is most likely due to anomaly in the data. Please check that data files have recomended format, units and test schedule

    0844.data.log

  • 0 in reply to Ivan Petrusevski
    TI__Guru** 105590 points

    Hello Ivan,

    I took a look at your log file, is this a standard discharge curve for your battery? I haven't seen a voltage discharge curve with so many different regions like this. Is it possible you can perform the relax-discharge-relax with only one cell? This will lead to a better chemistry ID match using the GPCCHEM tool.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 80 points

    Hi Wyatt,

    There are voltages of each cell in the dataset I sent you. It would not change significantly if we rip a part one battery and use one cell only. Can you use those data or you need an other cycle with one cell only?

    In addition, here is a link where you can find a basic info on this battery (we are using Li-Polymer standard Cells / Batteries – H320 series)  

    Best regards,

    Ivan Petrusevski

  • 0 in reply to Ivan Petrusevski
    TI__Guru** 105590 points

    Hello Ivan,

    Let me check with the team and see what I can do to get your cells characterized.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 80 points

    Hello Wyatt,

    Do you have any news on this topic?

    Ivan Petrusevski

  • 0 in reply to Ivan Petrusevski
    TI__Guru** 105590 points

    Hello Ivan,

    In order for the pack to be characterized we will need individual cells, could you run the same characterization with one cell, then we will know if there is a match in the database. Sometimes battery packs have strange IR losses in the traces that cause a characterization mismatch using the online tool.

    Sincerely,

    Wyatt Keller

  • 0 in reply to Wyatt Keller
    Prodigy 80 points

    Hello Wyatt,

    We managed to take one cell from the pack and run the test. Now we got the 5% deviation, which is a way better that previous 15%. Please find all data attached and please let me know your thoughts.

    Best regards,

    Ivan Petrusevski1_edited.log1881.GPCPackaged.zipGPCPackaged-report (1).zip

  • 0 in reply to Ivan Petrusevski
    TI__Guru** 105590 points

    Hello Ivan,

    Around 5% or less is where we usually aim for DOD accuracy so this will work fine.

    Sincerely,

    Wyatt Keller