BQ40Z80: BQ40Z80RSMT/R Chemical ID selection support.

Kamil Leskiewicz

Part Number: BQ40Z80
Other Parts Discussed in Thread: BQSTUDIO, BQ27426

Hello Texas Instruments INC.,

I have the BMS 6S design with BQ40Z80 IC and BAK N18650CP Lithium-ion Rechargeable Cell. I created charge/discharge profile based on "Simple Guide to Chemical ID Selection Tool (GPC)" document. I received GPC report with ChemID -> 5829 as a best chemical ID but this ID is not exist on the bqStudio chemical ID list. In the received report I see note that "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". Can you help me with this issue?

Profile of my Li-ion cell on picture below. As you can see in the discharge mode I used CV discharging option (2.5V) on my load. Do you think that this is a reason of the problem with ChemID selection?

I will be grateful for your support.

Regards,

Kamil Leśkiewicz

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GPC Report:

Chemistry ID selection tool, rev=2.53

Configuration used in present fit:

ProcessingType = 2

NumCellSeries = 1

ElapsedTimeColumn=0

VoltageColumn = 1

CurrentColumn = 2

TemperatureColumn = 3

Best chemical ID : 5829 Best chemical ID max. deviation, % : 7.6

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, %

3142 bq27421-G1D: 4.4V LiCoO2 23.23

354 bq27411-G1C: 4.35V LiCoO2 25.48

128 bq27421-G1A: 4.2V LiCoO2 38.02

312 bq27421-G1B: 4.3V LiCoO2 40.23

Best generic ID 3142

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, %

1210 bq27621: (ALT_CHEM1) 4.3V LiCoO2 23.33

354 bq27621: (ALT_CHEM2) 4.35V LiCoO2 25.48

1202 bq27621: (default) 4.2V LiCoO2 25.66

Best generic ID 1210

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, %

3142 bq27426: (ALT-CHEM2) 4.4V LiCoO2 23.23

3230 bq27426: (default) 4.35V LiCoO2 24.64

1202 bq27426: (ALT_CHEM1) 4.2V LiCoO2 25.66

Best generic ID 3142

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

Warning: First OCVpoint has non-zero current I= 0.003 Please make sure you have a 2 hr relaxation period before the beginning of discharge.

Warning: Last OCVpoint has non-zero current I= 0.002 Please make sure you have a 5 hr relaxation period after the end of discharge.

//----------------------------------------------------------------------------------------------------------------------------------------------------------------------------//

BAK_N18650CP_3350mAh.zip CHEMICAL_ID_CHARGE_DISCHARGE_GRAPH.xlsx

over 2 years ago

0 Wyatt Keller over 2 years ago

TI__Guru** 105770 points

Hello Kamil,

It is possible the CV discharge caused the tool have some larger errors since it is expecting a constant current discharge until terminate voltage where it should immediately stop. Please try to test with only constant current discharge and stop discharge at terminate, this should improve the tools results.

Also make sure you update the chem ID database, in bqstudio there should be a link at the bottom next to the version you are using. Following the link to update the database.

Sincerely,

Wyatt Keller

0 Kamil Leskiewicz over 2 years ago in reply to Wyatt Keller

Prodigy 30 points

Hello Wyatt,

Yes, we are repeating charging/discharging profile of our Lithium-ion cell . I think that tomorrow we will have a correct profile graph without CV in discharging mode. I will send new data to GPC tool and I will let you know.

I have updated chemistry list in bqstudio to version 992 but I cannot to find ID 5829. Please see the attached pictures.

Regards,

Kamil Leskiewicz

+1 Wyatt Keller over 2 years ago in reply to Kamil Leskiewicz

TI__Guru** 105770 points

Hello Kamil,

Sounds good, if you have any issues with the new report let us know.

Make sure you click the checkbox at the top of the table to include chem IDs that don't contain turbo mode support. Most applications do not require turbo mode data so there are a lot more chem IDs available without turbo mode support.

Sincerely,

Wyatt Keller

0 Kamil Leskiewicz over 2 years ago in reply to Wyatt Keller

Prodigy 30 points

Hello Wyatt,

I found my BAK N18650CP cell as ID 5267 in database version 992 with enabled "include chemistry IDs that do not support Turbo mode 2". This is good information. Now we can start to preparing the golden image for our BMS.

Thank you for support.

And additional information:

We repeated charging/dischaging profile without CV in discharging mode as you can see on the picture below but GPC report still shows ID 5829 as best chemical ID for BAK N18650CP. This is very interesting what is the reason of this. I will be grateful for any information. In atachement you can find our data from measurement.