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BQ27510: BQ27510DRZR-G3

Soumya
Prodigy 645 points
Part Number: BQ27510
Other Parts Discussed in Thread: GPCCHEM, BQSTUDIO, BQ27426,

Hi,

My customer is working with implementing the BQ27510-G3 into our system and had a particular question regarding the battery used with the fuel gauge. Can TI help to characterize a cell that they provide? Their Arbin tester cannot provide thermistor data so as of right now GPCCHEM does not appear to be an option which is typically recommended by TI. How can we help?

Thanks,
Soumya

  • 0
    TI__Guru* 76230 points
    Hi Soumya
    They can use the arbin to cycle the cell connnected to a TI EVM and then use the EVM thermistor and logging functionality of bqstudio to extract the required files for gpcchem.

    Let me know if you have further questions.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 215 points

    Hi Onyx,

    I have attempted to use gpcchem but am having some issues. The tool appears to have some issue with detecting the discharge portion of the log file as the following error is returned:

    The following errors were reported by the calculation engine:
    Error: No discharge portion found Make sure discaharge current is negative N_points= 2 0 0

    Would you be able to provide some guidance on addressing this error? There is a clear discharge portion in the log I am sending to gpcchem so I am thinking that this may be due to a formatting issue.  If possible, I would like to provide the log file for review but it appears e2e has trouble with attaching .csv files.

    Thanks,

    Anthony

  • 0 in reply to Anthony Elbancol
    TI__Guru* 76230 points
    pls use the insert code, attach files on the bottom right of this page to attach your log file.
    Did you carefuly follow the instructions for preparing the files for submission on gpcchem?
    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 215 points

    Hi Onyx,

    I received some guidance from Yevgen Barsukov, and it looks like there were a few points of positive current that interfered with the detection of discharge/rest periods. Are readings like these expected? There was nothing in the hardware setup that should have resulted in a positive current so it looks like this was some noise that was picked up by the fuel gauge. Note that I was originally reading from the InstantaneousCurrent register. The AverageCurrent register was devoid of these random positive current readings.

    In any case, a chemical ID report was generated. I am using the bq27510-G3, but the chemical IDs in the report are for device families other than the one I am using (bq27411, bq27421, bq27621, and bq27426). Which chemical ID should be used for the bq27510-G3? Attached is the GPC report for reference.

    Thanks,

    Anthony

    Fullscreen 7462.GPC_report.txt Download 
    Chemistry ID selection tool, rev=2.46		
		
Configuration used in present fit:		
ProcessingType=2 		
NumCellSeries=1 		
ElapsedTimeColumn=0 		
VoltageColumn=1 		
CurrentColumn=2 		
TemperatureColumn=3		
		
Best chemical ID : 2074	Best chemical ID max. deviation, % : 2.28	
		
		
		
Summary of all IDs with max. DOD deviation below 3%		
		
Chem ID	max DOD error, %	Max R deviation, ratio
2074	2.28	1.57
1116	2.73	0.27
2092	2.85	1.99
150	2.85	1.65
		
Max. deviations for best ID is within recommended range. Chosen best chemical ID is suitable for programming the gauge.		
		
		
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	4.38
3142	bq27421-G1D: 4.4V LiCoO2	4.77
312	bq27421-G1B: 4.3V LiCoO2	4.83
128	bq27421-G1A: 4.2V LiCoO2	5.46
Best generic ID 354		
Max. deviations for best generic ID is within recommended range. Please chose this ID in your device configuration or device family.		
		
		
Device / Family #2		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
1210	bq27621:  (ALT_CHEM1) 4.3V LiCoO2	3.54
1202	bq27621: (default) 4.2V LiCoO2	4.22
354	bq27621:  (ALT_CHEM2) 4.35V LiCoO2	4.38
Best generic ID 1210		
Max. deviations for best generic ID is within recommended range. Please chose this ID in your device configuration or device family.		
		
		
Device / Family #3		
Generic Chem ID	Device/ Voltage/ Chemistry	max DOD error, %
1202	bq27426: (ALT_CHEM1) 4.2V LiCoO2	4.22
3230	bq27426: (default) 4.35V LiCoO2	4.34
3142	bq27426: (ALT-CHEM2) 4.4V LiCoO2	4.77
Best generic ID 1202		
Max. deviations for best generic ID is within recommended range. Please chose this ID in your device configuration or device family.

  • 0 in reply to Onyx Ahiakwo
    Prodigy 215 points
    Hi Onyx,

    Another question had just come to mind regarding the battery being identified. The battery being used in this application may be charged to 4.35V, but in the actual application, it will only be charged to 4.2V. In this case, when performing the chemistry identification charge and discharge cycle, should the cell be charged to 4.35V or 4.2V?

    Thanks,
    Anthony
  • 0 in reply to Onyx Ahiakwo
    TI__Guru* 76230 points
    You were to use the average current and not the instantaneous current.

    The beauty of the bq27510 is that you can program any chem id instead of the ROM gauges where you are restricted to just three default chem ids. That said, you can use any of the following from the report

    2074
    1116
    2092
    150

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 215 points

    The end application requires that a battery voltage of 4.2V corresponds to 100% state of charge. If the b27510-G3 was configured with the Chem ID of a 4.35V battery, would an OCV measurement at 4.2V yield a state of charge < 100%? If this is the case, would it be advisable to stick with the 4.2V battery Chem ID?

    If it is still advisable to use the 4.35V Chem ID, will the cell need to be charged to 4.35V during the learning cycle even if the end application will only charge the battery to 4.2V?

  • 0 in reply to Anthony Elbancol
    TI__Guru* 76230 points
    During the learnig cycle the gauge should be charged to the max voltage in the cell data sheet and discharged to the min voltage as well.
    after learning completes, you can adjust charge voltage and terminate voltage to what ever value your application needs. The gauge will adjust the FCC and 100% will now correspond to 4.2V.

    so that being said use 4.35 if that is what your cells is rated for.

    thanks
    Onyx
  • 0 in reply to Onyx Ahiakwo
    Prodigy 215 points

    Hi Onyx,

    What are the implications of using 4.2V instead of 4.35V? Is the only result that Qmax would be lower than the stated capacity in the battery datasheet? This is expected and acceptable since as stated before, this application will only see a maximum battery voltage of 4.2V.  Is there something else that is not being considered?

    This applies to the chemical ID discharge cycle as well. What are the consequences of using 4.2V as the charge voltage instead of 4.35V?

    Thanks,

    Anthony

  • 0 in reply to Anthony Elbancol
    TI__Guru* 76230 points
    Hi Anthony
    Qmax may not learn. You need to have >90% of design capacity for qmax to learn. At 4.2V, that may not be up to 90% charge
    Atfer learning has taken place you can then adjust the voltage to 4.2


    thanks
    Onyx