![\"C-rates](\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/5e9effed-5b8d-4a02-a8d6-ab1e00dc6442\/e4e2cee9-9ecf-4033-ae62-ab1e00dfbbf5_curve-ntgk-parameters.jpg?width=690&upscale=false\")
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Hello,<\/p>\n
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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.<\/p>\n
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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.<\/p>\n
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![\"\"](\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/5e9effed-5b8d-4a02-a8d6-ab1e00dc6442\/777c50e5-67f7-4ed2-8bbc-ab260109b889_model-parameters.jpg?width=690&upscale=false\")
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![\"\"](\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/5e9effed-5b8d-4a02-a8d6-ab1e00dc6442\/5029deea-c74a-401e-8da7-ab260109f968_model-options.jpg?width=690&upscale=false\")
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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.<\/p>\n
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![\"\"](\"https:\/\/us.v-cdn.net\/6032193\/uploads\/attachments\/5e9effed-5b8d-4a02-a8d6-ab1e00dc6442\/8a19e946-73d8-47cd-9313-ab26010c0ad0_50ah-pouch-cell-calculatedparameters-exp-and-fitted-reults.jpg?width=690&upscale=false\")
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Text file 1C rate (time in seconds | voltage in V):<\/p>\n
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Crate 1.0<\/p>\n
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0001e+00 3.400e+00 <\/p>\n
<\/p>\n
0068e+00 3.252e+00 <\/p>\n
<\/p>\n
0194e+00 3.252e+00 <\/p>\n
<\/p>\n
0332e+00 3.249e+00 <\/p>\n
<\/p>\n
0466e+00 3.247e+00 <\/p>\n
<\/p>\n
0597e+00 3.239e+00 <\/p>\n
<\/p>\n
0862e+00 3.231e+00 <\/p>\n
<\/p>\n
0994e+00 3.225e+00 <\/p>\n
<\/p>\n
1260e+00 3.217e+00 <\/p>\n
<\/p>\n
1392e+00 3.213e+00 <\/p>\n
<\/p>\n
1657e+00 3.206e+00 <\/p>\n
<\/p>\n
1922e+00 3.198e+00 <\/p>\n
<\/p>\n
2320e+00 3.188e+00 <\/p>\n
<\/p>\n
2585e+00 3.172e+00 <\/p>\n
<\/p>\n
3248e+00 3.119e+00 <\/p>\n
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3703e+00 2.889e+00 <\/p>\n
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3832e+00 2.576e+00 <\/p>\n
<\/p>\n
3878e+00 2.368e+00 <\/p>\n
<\/p>\n
3949e+00 2.146e+00 <\/p>\n
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3989e+00 2.003e+00 <\/p>\n
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\n<\/p><\/blockquote>\n
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Text file 2C rate:<\/p>\n
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Crate 2.0<\/p>\n
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0001e+00 3.400e+00 <\/p>\n
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0060e+00 3.187e+00 <\/p>\n
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0200e+00 3.178e+00 <\/p>\n
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0333e+00 3.172e+00 <\/p>\n
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0465e+00 3.165e+00 <\/p>\n
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0598e+00 3.156e+00 <\/p>\n
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0730e+00 3.151e+00 <\/p>\n
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0863e+00 3.141e+00 <\/p>\n
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0995e+00 3.131e+00 <\/p>\n
<\/p>\n
1261e+00 3.108e+00 <\/p>\n
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1515e+00 3.058e+00 <\/p>\n
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1656e+00 2.976e+00 <\/p>\n
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1744e+00 2.838e+00 <\/p>\n
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1776e+00 2.750e+00 <\/p>\n
<\/p>\n
1802e+00 2.599e+00 <\/p>\n
<\/p>\n
1825e+00 2.504e+00 <\/p>\n
<\/p>\n
1850e+00 2.383e+00 <\/p>\n
<\/p>\n
1892e+00 2.195e+00 <\/p>\n
<\/p>\n
1901e+00 2.101e+00 <\/p>\n
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1913e+00 2.012e+00 <\/p>\n
\n<\/p><\/blockquote>\n
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Text file 3C rate:<\/p>\n
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Crate 3.0<\/p>\n
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0001e+00 3.400e+00 <\/p>\n
<\/p>\n
0001e+00 3.134e+00 <\/p>\n
<\/p>\n
0134e+00 3.118e+00 <\/p>\n
<\/p>\n
0267e+00 3.109e+00 <\/p>\n
<\/p>\n
0400e+00 3.098e+00 <\/p>\n
<\/p>\n
0532e+00 3.090e+00 <\/p>\n
<\/p>\n
0665e+00 3.073e+00 <\/p>\n
<\/p>\n
0798e+00 3.055e+00 <\/p>\n
<\/p>\n
0919e+00 3.027e+00 <\/p>\n
<\/p>\n
0997e+00 2.990e+00 <\/p>\n
<\/p>\n
1041e+00 2.955e+00 <\/p>\n
<\/p>\n
1075e+00 2.912e+00 <\/p>\n
<\/p>\n
1087e+00 2.869e+00 <\/p>\n
<\/p>\n
1113e+00 2.823e+00 <\/p>\n
<\/p>\n
1155e+00 2.623e+00 <\/p>\n
<\/p>\n
1201e+00 2.472e+00 <\/p>\n
<\/p>\n
1198e+00 2.388e+00 <\/p>\n
<\/p>\n
1226e+00 2.219e+00 <\/p>\n
<\/p>\n
1226e+00 2.180e+00 <\/p>\n
<\/p>\n
1250e+00 2.009e+00 <\/p>\n
\n<\/p><\/blockquote>\n
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Extra information:<\/span><\/strong><\/p>\n
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This is how the console looks like and what I’ve entered as input parameters in Ansys:<\/p>\n
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And here are the DOD in function of the U and Y parameters:<\/p>\n
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<\/p>\n","protected":false},"template":"","class_list":["post-39676","topic","type-topic","status-closed","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t