BQ34Z100-G1: review CHEM-ID

Sorry, I didn't made myself clear. The log file above is for calculating the CHEM-ID. It is not created in the process of learning cycle.

As you said : “I noticed that in your log file, the battery starts with 4.2v voltage at 100% SOC, but both chemID mentioned in your post have a full charge voltage of 4.35v? ”. 

I also think it is strange. Here are the parameters provided by the cell manufacturer:

Li-Poly
Nominal capacity:22000mAh
Minimum capacity:20480mAh
Nominal voltage:3.7V
Open-Circuit Voltage:4.15~4.20V

I attache the new log file for calculating the ID(Charge -> relax for 2 hours -> Discharge -> relax for 5 hours). Could you please have a look? 

Thank you for all your help.

3443.roomtemp_rel_dis_rel.log

Hi,

    If your actual max cell voltage is 4.2v, but the matched ID advised a cell with max voltage of 4.35v, the ID can still be used.

    But please be careful about the bit I mentioned in above post, especially, the VOK but be cleared at the moment I mentioned above.

Hi,Steven

I did use the ID:3686(Best chemical ID,max. deviation, % : 1.2) for learning cycle with these following steps:

1. Enable IT

2. Send Reset command (0x0041)

3. C/7 Discharge to empty

4.Rest for 5 hours.Ensure that RUP_DIS is cleared and OCVTAKEN flag turns red

5. C/5 Charge to full

6. Rest for 2 hours.Ensure that VOK is cleared

(Stop here)

7. C/7 Discharge to empty

8. Rest for 5 hours.Ensure that VOK is cleared

But ID:3686 failed. Update Status(Learned Status) has not been updated to 05 (that is, it is still 04) after charging is completed.

The attachment is the log file of this learning cycle.

Because the maximum current of the equipment is about 180A, I downsize the current parameters,Design Capacity and Qmax Cell 0 by 5.65 times.

(I tried not to change the current setting and did the learning cycle again, but the result was the same.)

Thank you very much.

ID3686.logID3686.gg.csv

You latest log file (ID3686.log) doesn't have the discharge part that will update the impedance table. It just has the initial discharge to empty, relax and charge. RUP_DIS is 1 during the initial discharge, hence there won't be an impedance table update.

Hi,Dominik:

I'm discharging the battery now,I will post the discharge part later if you need.
But I think the result will be the same,Because I used to discharge-charge-discharge the battery again and again,

Update Status is always 0x04,and MAx Error is always 100%

Thank you.

Hi,Steven,Dominik:
This is the discharge part of this learning cycle
Learning cycle is still going on,I really need your help
Thank you

ID3686-2-discharge.log

Hi

   I have not been able to find anything abnormal in the charge rel discharge process with the only exception of you are charging the battery to full with a very low taper current, and the cell voltage is charged so high that even after a long relax, it is still 4.2v, so the DOD0 start with 0, I suspect even the internal OCV table can start with 4.2v as the highest OCV.

   I am not certain if this is the cause of your unsuccessful learning, but can you try with a reasonable taper current say at C/20 or C/30, and tune the charging voltage a little bit lower than 4.2v see if this could bring some change to your learning cycle

Hi,Steven：

I tried to set the taper current to C/20,and stop charging when the battery voltage is 4.199V(FC bit turns red)

but after VOK is cleared, Update Status is still 0x04

Hi,Steven

Any other suggestions?

I think the possible reason is that the CHEM-ID do not match?

I tried a few times and the results were similar:

Best chemical ID : 3686 Best chemical ID max. deviation, % : 1.2
Summary of all IDs with max. DOD deviation below 3%
Chem ID max DOD error, % Max R deviation, ratio
3686 1.2 2.16
3740 1.35 1.42
1712 1.82 4.46
1768 2.2 5.12

Best chemical ID : 3686 Best chemical ID max. deviation, % : 1.1
Summary of all IDs with max. DOD deviation below 3%
Chem ID max DOD error, % Max R deviation, ratio
3686 1.1 1.71
3740 1.37 0.99
1768 1.69 3.99
1835 1.96 4.16
1173 2.34 2.37

Parameters provided by battery manufacturers:
Nominal capacity：22000mah
Nominal voltage:3.7V
Min voltage:3.2V
Max voltage:4.2V

Totally different