BQ27Z558EVM-084: Chemical ID Diviation was above recommended level

?? ??

Prodigy 30 points

Part Number: BQ27Z558EVM-084
Other Parts Discussed in Thread: BQ27426, GPCCHEM, BQSTUDIO

Tool/software:

We followed the manual to measure for ChemID and the results were as follows.

It seems to me that this is due to the voltage drop at RelaxTime after the discharge is completed.

If there is no problem with the measurement, can I program this ChemID and proceed to the next step?

Attached is an image of the data sheet for the battery used.

LPHD5026053 800mAh 5C.pdf

____________________________________________

Chemistry ID selection tool, rev=2.54

Configuration used in present fit:
ProcessingType = 2
NumCellSeries = 1
ElapsedTimeColumn = 0
VoltageColumn = 1
CurrentColumn = 2
TemperatureColumn = 3

Best chemical ID : 141 Best chemical ID max. deviation, % : 8.36

Summary of all IDs with max. DOD deviation below 3%

Chem ID max DOD error, % Max R deviation, ratio
0 0 0

Warning: Deviation is above recommended level. New chem ID needs to be released for this cell. Please contact your TI representative to send the cell to Dallas for characterization

Selection of best generic ID for ROM based devices like bq274xx

Device / Family #1
Generic Chem ID Device/ Voltage/ Chemistry max DOD error, %
128 bq27421-G1A: 4.2V LiCoO2 13.26
312 bq27421-G1B: 4.3V LiCoO2 14.65
3142 bq27421-G1D: 4.4V LiCoO2 15.4
354 bq27411-G1C: 4.35V LiCoO2 15.54
Best generic ID 128
Warning: Deviation for best generic ID is above recommended level for this device / family. Consider using another device, flash based gauge or RAM programming of custom ID.

Device / Family #2
Generic Chem ID Device/ Voltage/ Chemistry max DOD error, %
1210 bq27621: (ALT_CHEM1) 4.3V LiCoO2 13.3
1202 bq27621: (default) 4.2V LiCoO2 14.67
354 bq27621: (ALT_CHEM2) 4.35V LiCoO2 15.54
Best generic ID 1210
Warning: Deviation for best generic ID is above recommended level for this device / family. Consider using another device, flash based gauge or RAM programming of custom ID.

Device / Family #3
Generic Chem ID Device/ Voltage/ Chemistry max DOD error, %
3230 bq27426: (default) 4.35V LiCoO2 14.24
1202 bq27426: (ALT_CHEM1) 4.2V LiCoO2 14.67
3142 bq27426: (ALT-CHEM2) 4.4V LiCoO2 15.4
Best generic ID 3230
Warning: Deviation for best generic ID is above recommended level for this device / family. Consider using another device, flash based gauge or RAM programming of custom ID.

____________________________________________

over 1 year ago

0 Adrian over 1 year ago

TI__Mastermind 37761 points

Hello,

No, I would not recommend programming that ChemID, the DOD error percentage is too large. The biggest concern is the voltage drop at the end of discharge during the relax time. If there is no current flowing through the battery we do not expect this behavior of the battery voltage dropping. Is the battery connected to anything else that could be drawing current? Also, after constant current charge, we usual expect to see a constant voltage charge.

Regards,

Adrian

0 ?? ?? over 1 year ago in reply to Adrian

Prodigy 30 points

Hello Adrian.

Thank you for reply.

Measured again, and the same voltage drop was observed.
This time the divitation was 0.98%, but is this a problem?

I'm currently inquiring with the battery supplier about the battery characteristics.

0 Adrian over 1 year ago in reply to ?? ??

TI__Mastermind 37761 points

Hello,

Can you send me the report file that you got back from the GPCCHEM tool? As well as the data that was submitted.

Regards,

Adrian

0 ?? ?? over 1 year ago in reply to Adrian

Prodigy 30 points

Hello, Adrian

I sent the file and log images to DM.

0 Adrian over 1 year ago in reply to ?? ??

TI__Mastermind 37761 points

Hello,

I reviewed the files and it should be perfectly fine to use the ChemID that was specified in the report file.

Regards,

Adrian

0 ?? ?? over 1 year ago in reply to Adrian

Prodigy 30 points

Helo Adrian.
I have learned the life cycle step using chemID,
BQstudio crashed in the middle of the measurement and Lstatus was fixed at 5.
Even after entering the GAUGE_EN and RESET commands, Lstatus does not go to 4, but alternates between 5 and 1.
Do I set Lstatus to 5 and start with the discharge process?
Or is there another way to set Lstatus to 4?

0 Adrian over 1 year ago in reply to ?? ??

TI__Mastermind 37761 points

Hello,

Set LStatus to 5 and start the discharge process.

Regards,

Adrian

0 ?? ?? over 1 year ago in reply to Adrian

Prodigy 30 points

Hello Adrian,

The battery was discharged and Lstatus was 06.
So I created a Goldenimage but the datasheet says the command needs to be activated (attached image). What should this do?

Also, is bqstudio always required to program the goldenimage to the actual IC? If so, do I need to install the same 4 pin terminals on the PCB as on the EVM?

Thank you again and again, it would be helpful to know as my knowledge of gauges ICs is lacking.

0 Adrian over 1 year ago in reply to ?? ??

TI__Mastermind 37761 points

Hello,

When the gauges are shipped out to customers, on the first power up, the IT Enable command should be sent to the gauge. This enables impedance track algorithm.

You do not need to use BQStudio to program the golden image onto the IC. This can be done using an MCU. You can read this document regarding gauge communication: https://www.ti.com/lit/an/slua801/slua801.pdf

Regards,

Adrian

0 ?? ?? over 1 year ago in reply to Adrian

Prodigy 30 points

Hello Adrian,

I understand how to write Golden Image.

However, it seems that INTpinn is not usually enabled.
I tried to enable INT for flash from the MCU but failed.

I would like to run INT_EN in BQstudio for testing,
How do I enter the command?

Thank you.

Wako.

0 Adrian over 1 year ago in reply to ?? ??

TI__Mastermind 37761 points

Hello Wako,

In data memory, go to "Settings", then "IO Config" and INT_EN is bit 2.

Regards,

Adrian

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BQ27Z558EVM-084: Chemical ID Diviation was above recommended level