BQ34Z100-G1: Update Status does not change from 0x04 to 0x05 for NiMH batteries

Hi MM,

Thank you for the detail explanation and all relevant information. I have seen a few times before that update status randomly stops updating. Continue the learning cycle process and see if you can get Qmax and the Ra table to both update, if you can you have reached learned status 0x06.

Regards,

Evan

Evan-san,

I have run the learning cycle several times, but the Update Status remains at 0x04 even after completing the process normally, Naturally, Ra Tables is not updated either, so I am looking into the problem.

While investigating, I found that the Update Status does not change to 0x05 even after fully charging the battery.

Do you think that if I continue to run the learning cycle several times, it will learn correctly?

Regards,

MM

Hi MM,

I overlooked that you are changing ChemIDs, please use the best ChemID yielded from the gpcchem tool (6121).

I believe you can gauge is not detecting full charge.

I recommend verifying all parameters are listed are configured properly and Full charge is reached.

Regards,

Evan

Evan-san,

The results obtained from the GPCCHEM tool are below.

From the list, I think 6116 or 6121 is the best, and I use them, and in both cases, the FC flag is established at the timing of ⊿T.

Is there a big difference between 6116 and 6121?

Also, I would like to know about the following you mentioned.

LION batteries can easily satisfy conditions 1, 2 and 3 due to CC and CV control, but is this also true for the NiMH charging process?

If so, do I need to set it to 1600mV per cell since the maximum voltage during charging is approximately 4.8V?

NiMH has termination using ⊿T and ⊿V control, so there is no concept of taper current, right?

I think that the FC flag is set by the trigger of ⊿T or ⊿V due to CC charging before the taper current is reached, and I have confirmed this from the log data in actual operation.

Regards,

MM

Hi MM-san,

The second number is the DOD% error, meaning your best match is 6116 with DOD error 5.51%. Typically, we do not recommend using a chemID match of more than 3%. If you would like to characterize your cells you can reach out to your supporting FAE or local TI office for help getting a custom ChemID for your cells.

The higher the DOD% error the more the OCV curve of your cell varies from the ChemIDs OCV curve.

You may need to relax for a longer time with this chemistry, I have seen cases where it takes up to 24 hours for the battery to fully relax, please allow me sometime to algin with my team on any differences with NiMH learning process.

Regards,

Evan

Evan-san,

From your explanation, I understood that not only ChemID but also OCV is very important.

I will use ChemID 6116 and try increasing the relaxation time.

And I will contact you as soon as we know the results.

Regards,

MM

Hi MM-san,

Sounds good, please share data when available.

Regards,

Evan

Evan-san,

We revaluated Chem ID6121 and 6116.

< Left: ChemID 6116, Right : ChenID 6121 >

As a result, Update Status does not transition to 0x05 during the process from discharging to charging, but it transitions to 0x05 during the process from charging to discharging.

VOK, RUP_DIS, and FC seem to be transitioning correctly, but I don't understand why this problem occurs.

It is also known that if the Update Status is 0x05 and the learning cycle is executed again in the same way, the Update Status will become 0x06.

Do you think that the error with ChemID is more than 3% is the cause?

20240413LC_ID6121.log

20240412LC_ID6116.log

20240413_after.gg.csv

Regards,

MM

Hi MM-san,

If you have reached learned status 0x05 then a Qmax update has occurred, if you reach 0x06 the ra table have updated and you have completed a learning cycle process. Update status will increment when the proper conditions are met.

Regards,

Evan

Evan-san,

Charge after completely discharging, and Update Status will not transition to 0x05 during the relaxation time after full charge.

However, the battery is fully charged and then discharged, and the UpdateStatus transitions to 0x05 during the relaxing time after being fully discharged.

In other words, Qmax is not updated after full charge, but only after full discharge.

_

Correct operation: [Discharge]=>[Relax]=>[Charge]=>[Full charge (FC flag goes 'H')]=>[Relax (VOK goes 'L', UpdateStatus goes 0x05)]

Current operation: [Discharge]=>[Relax]=>[Charge]=>[Full charge (FC flag goes 'H')]=>[Relax (VOK goes 'L', UpdateStatus remains 0x04)]

_

I found that the UpdateStatus changes to 0x06 after running the learning cycle twice, but is this normal behavior?

The left and right images above are continuous movements.

My computer froze, and when I restarted it, the data was cut off.

Regards,

MM

Evan-san,

I appreciate your support.

If you know the conditions for the Update Status to become 0x05 during the relaxation time after charging, please let me know.

It appears that FC, RUP_DIS, VOK flags, and termination are transitioning correctly.

Is it correct to say that the cause is that the battery being used is outside the 3% error range of ChemID?

Regards,

MM

Hello, 

Evan is currently OoO, please expect a delayed response. 

Regards, 

Jonny.

Evan-san,

Thank you for your answer.

This was the first time I had encountered this kind of phenomenon, so I didn't know the cause.

I'll try a different battery, so I'll close it for now.

Regards,

MM