Cell imbalance using Thevenin model

[MustafaDragonborne]

Hi everyone. Is there a way to simulate a battery pack with imbalanced cells using liionpack i.e. the cells have different initial voltages?

[TomTranter]

See this example https://github.com/pybamm-team/liionpack/blob/develop/examples/different_initial_soc.py

[MustafaDragonborne]

Thank you so much @TomTranter
This is highly appreciated! 😃

[MustafaDragonborne]

@TomTranter I guess I must've been clear from the beginning and I'll update the question too. How do I simulate cell imbalance using the Thevenin model?

[MustafaDragonborne]

I also got this error when running the example that was specified.

Traceback (most recent call last):
File "/home/mustafa/Downloads/pycharm-community-2022.3.3/plugins/python-ce/helpers/pydev/pydevd.py", line 1496, in _exec
pydev_imports.execfile(file, globals, locals) # execute the script
File "/home/mustafa/Downloads/pycharm-community-2022.3.3/plugins/python-ce/helpers/pydev/_pydev_imps/_pydev_execfile.py", line 18, in execfile
exec(compile(contents+"\n", file, 'exec'), glob, loc)
File "/home/mustafa/Documents/pybamm_ArtificialData/liion_diff_soc_example.py", line 43, in
c_s_n_init, c_s_p_init = lp.update_init_conc(
File "/home/mustafa/miniconda3/envs/testenv2/lib/python3.9/site-packages/liionpack/sim_utils.py", line 53, in update_init_conc
x, y = lp.get_initial_stoichiometries(SoC, param)
File "/home/mustafa/miniconda3/envs/testenv2/lib/python3.9/site-packages/liionpack/sim_utils.py", line 31, in get_initial_stoichiometries
return esoh_solver.get_initial_stoichiometries(initial_soc)
File "/home/mustafa/miniconda3/envs/testenv2/lib/python3.9/site-packages/pybamm/models/full_battery_models/lithium_ion/electrode_soh.py", line 477, in get_initial_stoichiometries
raise ValueError(
ValueError: Initial value must be a float between 0 and 1, or a string ending in 'V'

[philgravy]

Hey MustafaDragonborne, were you ever able to resolve this? I'm also trying to perform an experiment with different initial SOCs

[MarcoZangrandi]

I don't know if it still helps, but the error is that you cannot provide an array as the initial SOC.

c_s_n_init, c_s_p_init = lp.update_init_conc(
    param, SoC=np.array([0.5, 0.6]), update=False
)

You have to provide a scalar number to SoC, so I solved it by running a for loop on all the cells for which I had defined an initial SOC array.