Supercapacitor model in simulink

Hi,

I am trying to build up a simulink with supercapacitor model from library, but I find one strange thing that when I put the initial voltage equals to rated voltage of supercapacitor, theoritically, the initial state of charge should be 100%, but when I run the simulation, I get the results that the output initial state of charge is 92% not 100%, I don't why I get this strange result. Could anyone help with this? Thank you very much!

[Anmol Dhiman]

Can you share the model and inputs for the above model? That would help me out in reproducing the error.

[Qian Xun]

Hi,

Sorry for my late response. Please find the attached simulink file for supercapacitor model.

I found one strange thing that the SoC decreases from around 99.5% when I put the series number as 1, but the SoC decreases from around 93% when I put the series number as 18.

As you know, for Maxwell supercapacitor, they have 3000F/2.7V cells, and they also have 166F/48V pacakge. I think if you use 18 cells connected in series you can get 166F/48V package. So I am not sure which parameters for my case is correct? Do you have any ideas?Thank you very much!I am looking forward to youre reply.

BR,

Qian

Answer 1

[Gokul Krishna N]

This is actually because of the internal resistance (ESR) of the supercapacitor. As the number of cells increases, the ESR gets multiplied by the number of cells. (basically Resistors in series). As a result, you will observe a voltage drop. This is why you are getting lesser SoC with higher number of cells in series.

I believe this is the explanation...

Yes, its a little late to answer the question, but I hope it helps others who visit this question!