Learning Forum

[Battery]

 

Hello,

For my thesis I'm designing a batterypack for an application. Currently I'm trying to determine the U and Y coefficients for the NTGK battery model. Because I'm not able to do any experiments yet I used a graph delivered by the battery supplier (Voltage in functon of time in minutes). You can see the graph below. I extracted the values from the graph and wrote them in three .txt files (1C;2C and 3C). Completely below the text files are shown.

With the parameter estimation tool I've readed the .txt files into Ansys. The tool calculated the Y and U parameters as shown below. I also added the model options (50Ah 3,2V pouch cell). As you can see the parameter bo isn't correct because it's shown in a red box. This parameter should be a positive number.

The experimental and fitted results are shown below. As you can see these results doesn't match the first graph at all and I can't figure it out what I'm doing wrong.

Text file 1C rate (time in seconds | voltage in V):

Crate 1.0

0001e+00  3.400e+00 

0068e+00  3.252e+00 

0194e+00  3.252e+00 

0332e+00  3.249e+00 

0466e+00  3.247e+00 

0597e+00  3.239e+00 

0862e+00  3.231e+00 

0994e+00  3.225e+00 

1260e+00  3.217e+00 

1392e+00  3.213e+00 

1657e+00  3.206e+00 

1922e+00  3.198e+00 

2320e+00  3.188e+00 

2585e+00  3.172e+00 

3248e+00  3.119e+00 

3703e+00  2.889e+00 

3832e+00  2.576e+00 

3878e+00  2.368e+00 

3949e+00  2.146e+00 

3989e+00  2.003e+00 

 

Text file 2C rate:

Crate 2.0

0001e+00  3.400e+00 

0060e+00  3.187e+00 

0200e+00  3.178e+00 

0333e+00  3.172e+00 

0465e+00  3.165e+00 

0598e+00  3.156e+00 

0730e+00  3.151e+00 

0863e+00  3.141e+00 

0995e+00  3.131e+00 

1261e+00  3.108e+00 

1515e+00  3.058e+00 

1656e+00  2.976e+00 

1744e+00  2.838e+00 

1776e+00  2.750e+00 

1802e+00  2.599e+00 

1825e+00  2.504e+00 

1850e+00  2.383e+00 

1892e+00  2.195e+00 

1901e+00  2.101e+00 

1913e+00  2.012e+00 

 

Text file 3C rate:

Crate 3.0

0001e+00  3.400e+00 

0001e+00  3.134e+00 

0134e+00  3.118e+00 

0267e+00  3.109e+00 

0400e+00  3.098e+00 

0532e+00  3.090e+00 

0665e+00  3.073e+00 

0798e+00  3.055e+00 

0919e+00  3.027e+00 

0997e+00  2.990e+00 

1041e+00  2.955e+00 

1075e+00  2.912e+00 

1087e+00  2.869e+00 

1113e+00  2.823e+00 

1155e+00  2.623e+00 

1201e+00  2.472e+00 

1198e+00  2.388e+00 

1226e+00  2.219e+00 

1226e+00  2.180e+00 

1250e+00  2.009e+00 

Extra information:

This is how the console looks like and what I've entered as input parameters in Ansys:

And here are the DOD in function of the U and Y parameters:

 

 

[Battery]

I'm not sure if I understand your question correctly but if you want to find the .txt files in Ansys through the parameter-estimation-tool this is the path:

[salih kaya]

hi did you solve the problems? ı have the same problem, and  ansys doesnt helping :/

[Rob]

You emailed us on 3rd, and were pointed here within about 10minutes, it's then taken a week for you to post the above into a thread from 2019.  I'm assuming you've read https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v231/en/flu_ug/flu_bat_MSMD_sec_use_battery_model.html%23flu_bat_MSMD_sec_NTGK_input  

[salih kaya]

link is not opening, ı have no custemer id

[Rob]

Click on Help, then paste the above into the browser that opens. 

[salih kaya]

when ı click on help, it wants custemer id

[Rob]

Clicking on Help in Fluent requests a customer ID? 

[abdur raheem adam]

hi, i am doing the same battery capacity for my project as well. i have the data for internal resistance vs SOC. can i do parameter estimate or Y or U table from my data? or should my data only be in time and voltage as mentioned above?

[Rob]

You'll need the data in whatever format Fluent requests: I don't know if what you have is sufficient.