BQ28Z610-R1: RSOC jump caused by temperature changes during standstill

Hello,

Did you use our GPCRB tool for temperature compensation? This tool updates thermal parameters needed for when gauge operates at low temperatures.

Please provide a log file describing the above behavior. If possible, a BQStudio log file.

Regards,
Jose Couso

GPCRB tool has been done, the BQStudio log file as the attachment.log jump data.xlsx

Supplementary GG fileGG file.gg.csv

Hello,

Thanks for sharing the data, I will get back to you.

Regards,
Jose Couso

Hello,

I have questions regarding the log file. 

Why are you charging as temperature decreases? It is recommended to charge when temperature is stable. Are you manually increasing the temperature in a chamber? A soak time is recommended before start charging. 

It looks like the end of charge current is around 1269-mA. However, in your settings this is set different.


Can you please send the GPCRB results you obtained? The above parameters should have been updated. The zip file. Also, this tool should have been used according to your application. The data inputted should reflect the application.

I am curious why the battery voltage drops as the current seems to be "tapering". Voltage should stay constant.



Regards,
Jose Couso

Hello,

Please receive my reply for your questions:

 Why are you charging as temperature decreases?

- We are simulating the actual application scenarios of users.

It looks like the end of charge current is around 1269-mA. However, in your settings this is set different.

- The terminal is set to not charge below 0 ℃ or above 45 ℃, the current 1269-mA is not mean the current at EoC.

I am curious why the battery voltage drops as the current seems to be "tapering". Voltage should stay constant.

- The terminal is set with step charge. When the temperature is 5~45℃, the charge current is about 4000-mA,  When the temperature is 0~5℃, the charge current is about 2000-mA. At around 5 ℃, the battery is in constant current charging mode, After the temperature drops below 5 ℃, the charging current      decreases, resulting in a decrease in voltage.

Can you please send the GPCRB results you obtained?

- Please see the attachment.

Best regards

Tony

01#-report.zip02#-report.zip

Hello Tony,

Looking at the GPCRB report, I did a comparison with the current gg file you are using and the gg.out from the tool. You are supposed to be using the gg.out as it contains all changes in internal resistance and thermal model parameters for capacity predictions.




This tool also reports the new Rb ratio which should be used for low temperatures. Rb table is a private parameter. You can provide the srec file with the unseal key and I can update this for you. Or you could scale the ratio and write to the specific addresses in data memory. 2112.gg_out.csv

Regards,
Jose Couso

Hello Jose, 

The gg file we used is gg_out. Because the GG file I sent to you last time was after 3 cycles learning after import gg_out, so some parameters have been updated. 

But the new Rb ratio we don't use. The attachment is the srec file with gg_out of 02#-report.zip, please help to update Rb ratio for me, thanks. Please also tell me the specific addresses of Rb ration in data memory,thanks.

By the way, the register [RELAX_JUMP_OK] we enabled, May it be related to this RSOC jump?  IQ1090-B-1S4P-28z610R1-1-01-3775-1bei-1mR-R00-2023-9-2.rar

Hi Jose, 

Look forward to your reply, thanks.

Best regards

Tony

Hello Tony,

Please see below the Rb table addresses so that you can read and write to.


I have scaled the Rb table to the new ratio. You may read from the addresses to confirm. See the srec attachedhttps://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/196/Rb_5F00_low.srec

luotao01 said:

By the way, the register [RELAX_JUMP_OK] we enabled, May it be related to this RSOC jump?

This can be a factor. Please set it to zero. Also, make sure that the smoothing feature is set. Refer to Section 6.6 Impedance Track (IT) Configuration Options in the TRM.

Regards,
Jose Couso

Hello Jose,

Thanks for your reply, the srec I received. I will program the Rb_low.srec to test again after 2 learning cycles.

We hope that after the battery discharged to 0% RSOC at a low temperature of -10℃，and then restored to normal temperature, such as 25℃, the battery

can automatically recover some of its power, which means that RSOC can automatically restored to avove 0. So we disabled [LOCK0] and

enabled [RELAX_JUMP_OK] .

There is any other way that can achieve this without enabled [RELAX_JUMP_OK] ?

Best regards,

Tony

Hello Jose,

I'm sure the smoothing is set.

I tried to read the value of Rb using Advanced Comm I2C of bqstudio, but I don't know what's the start register. Please help me to input the command in the

attachment figure. And the value read out in this way should be in hexadecimal. How to convert it to decimal?

thanks a lot.

Best regards

Tony

Hi Tony,

I2C address is AA
Start Address is 3E
Bytes to Write is the address of Rb
Number of bytes to read is 2

An example of writing to data memory can be found in the Gauge communication app note. Section 4

Also, please reference to this Thread

Regards,
Jose Couso

Hi Jose

The updated srec is very helpful to me, thank you.

But there till are some questions need your help:

1.The RSOC jump is still exist,  but looks like there's been some improvement.(At the beginning, RSOC jumped from 34% to 4, and now it has jumped from 71 to 67)

2.Unable to read any information when sending instructions to read the value of Rb.

3.Can we change the value of Rb ourself? and how can we do it? I don't quite understand the Gauge communication app note.

4.How do we enter the interface shown in Figure 2 of the attachment.

Looking forward to your reply, thanks.

Best regards

Tony

Hi Tony,

1- Do you have a log to analyze what is happening? 
Please send the srec. I can further tweak the Rb table. I will need the input data you used for the GPCRB tool.

3- Please see this thread for detailed example.

4- These are private parameters. But with the given addresses you can change the values.

Please provide the files in the first bullet.

Regards,
Jose Couso

Hi Jose,

1.I will provide the SREC and log date tomorrow.

Sorry for that, the input data used for the GPCRB tool can't be found because it was made a long time ago. We only have the results of the GPCRB tool.

By the way, after we used GPCRB for temperature compensation, there is no RSOC jump during the Charge and discharge process at a fixed low temperature such as -10℃. 

The issue we are discussing this time is the RSOC jumped during relax mode with temperature drop(Please check the previous data I provide .log jump data.xlsx). 

And there is also no RSOC jump during relax mode before we enable the register [RELAX_JUMP_OK]., RSOC jump occured after enable the register [RELAX_JUMP_OK]. (After the battery discharge to 0% RSOC at a low temperature such as -10℃, for let the battery can automatically recover to above 0% RSOC at ordinary temperature such as 25℃, we disable the register [LOCK0] and enable the register [RELAX_JUMP_OK]. There is any other way that can achieve this without enable [RELAX_JUMP_OK] ?)

2.Whether we can use EV2400 and bqstudio to change the values of Rb.

Best regards

Tony

Hi Tony,

FCC dropped drastically, this is the reason of the RSOC drop. The gauge will stablish FCC based on temperature and load. At lower temperatures, there's expected to be less capacity. 

RSOC_HOLD and SMOOTH cannot be set at the same time. This causes erratic SOC behavior. Often we suggest to set SMOOTH

Please clear the RELAX_JUMP_OK bit.

luotao01 said:

2.Whether we can use EV2400 and bqstudio to change the values of Rb.

We do not reveal the Rb table. I believe this is not the problem. I can always further tweak the Rb if you provide me the input data of the GPCRB tool. 

Regards,
Jose Couso

Hello Jose:

Jose Couso said:

RSOC_HOLD and SMOOTH cannot be set at the same time. This causes erratic SOC behavior. Often we suggest to set SMOOTH

erratic SOC behavior-Can it be more specific? How will it become erratic?

Jose Couso said:

Please clear the RELAX_JUMP_OK bit.

Perhaps I didn't express myself clearly, this register needs to enable as follows.

Jose Couso said:

We do not reveal the Rb table. I believe this is not the problem. I can always further tweak the Rb if you provide me the input data of the GPCRB tool. 

You means we can use EV2400 and bqstudio to change the values of Rb?

I logged the room temperature and low temperature charge and discharge data again for GPCRB as follow attachment:

low temp and room temp data.rar

We used two samples discharging at -10℃ with the updated srec of Rb, and the RSOC will significantly jump. The data as follows. And for sample 2, I exported the srec and gg file before and after discharge.

sample 1.rarsample 2.rar

Hi Tony,

I received the data, I will get back to you.

luotao01 said:

erratic SOC behavior-Can it be more specific? How will it become erratic?

We have seen customers report this. We suggest not to set RSOC_HOLD and Smoothing together. See below the documentation for a different gauge which uses Impedance Track as well.

luotao01 said:

You means we can use EV2400 and bqstudio to change the values of Rb?

You can write to the Rb memory location I provided earlier. I will double check the data you provide to see if further tweaking is necessary. 


Regards,
Jose Couso

Hi Jose,

Jose Couso said:

I received the data, I will get back to you.

Look forward to your reply, thanks.

Best regards

Tony

Hi Tony,

In the test you attached, it looks like the SOC jumps during -10C and when it is discharging. Not at rest.

Please try again the test with this srec. uploadgg.gg.csvhttps://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/196/further_5F00_tweaked_5F00_RB.srec

Regards,
Jose Couso

Hi Jose,

Jose Couso said:

In the test you attached, it looks like the SOC jumps during -10C and when it is discharging. Not at rest.

We have two tests, one is dischargeing at -10℃ and the RSOC will significantly jump; another one is resting with the temperature dropping to -10℃ from room temperature and the RSOC will drop to 67% from 71%.

Best regards

Tony