The code provided doesn't work. I suppose the method suggested should work, however you've tangled in curve_fit. Read thoroughly a documentation (https://docs.scipy.org/doc/scipy/reference/generated/scipy.optimize.curve_fit.html). Moreover I think it is worth passing "jac" argument into the curve_fit since it can be easily calculated analytically and can improve the method noticeably.

Also you should check if your model (voltage function) is correct.

Dear Nupur Tembhare,

I suggest you to see links and attached files on topic.

https://arxiv.org/pdf/2102.06534.pdf

https://www.sfu.ca/~mbahrami/pdf/Theses/Thesis%20M.%20Yazdan%20Pour.pdf

https://www.mdpi.com/1996-1073/10/1/5

Best regards

https://stackoverflow.com/questions/68081164/how-to-match-simulated-data-to-experimental-data-of-a-battery-in-python-by-estim

Denis Perepukhov Thank you so much for your reply and I have updated the file above and I read the document as well however, I am still confused why this approach is not working. And, about the voltage formula; I am quite sure its correct that's why it is giving me the similar result only not fitting on each other. I just want the parameter to be adjusted.

Nupur Tembhare Well, I assume one of the problems is initial guess and the method just doesn't converge. I can recommend you normalize the experimental voltage before passing it into the optimization (if you do this don't forget to correct the function for optimization). Also try different methods (see "method" argument).