I’m trying to model a large EV battery. Say a few hundred volts and a few hundred amps. After change numerous parameters in the model, without success, I reduced it to a bare minimum of changes from the demo model. I’d like my first effort to be 100 series cells and 100 parallel cells, but model sets the battery voltage to zero, To eliminate any issues with the charger parameters, i’ve eliminated it and simply discharge into a resistor. I been all through the subcircuits, yet still cannot find the problem. Attach are my ultra-simplified models. One with the demo’s 10*10 battery, and the other one with only two changes, 100 series, 100 parallel
Li_ion_RonlyModel 10*10.plecs (76.2 KB)
Li_ion_RonlyModel 100*100.plecs (75.9 KB)
Well the problem is that the for the number of cells being 100, the output of V_OC calculation is -206V, so it gets limited at 0V due to the saturation blocks.
The problem seems to be the “polarizing voltage” calculation which calculates 514V somehow. What is wrong there? I have no idea, since I am not familiar with those equations you should debug it. For the case where the number of cells is 10, the polarizing voltage is smaller than the E_0, so the calculation yields positive voltage.
I agree that the “polarizing voltage” calculation is incorrect. It may be related to the K variable. If I manually change its value to something lower, then there is some resemblance of functionality. But without knowledge of exactly K represents, I’m just working blindly. I do have the whitepaper about this model, and it is helpful.
I am a newbe with PLECS. I cannot find where in the model or any in of the subsystems where certain variables are set. For instance, A, B, K, E_0. They all have values that I can display, but I cannot find anything that sets them.