predicting voltage knee point near end

[Thiyaga2025]

team pybamm,

i am trying to run simulations with OKane2022 parameter set for an NMC cell at c/3 discharge rate. I have difficulty matching the knee point in voltage curve near discharge ending. what property/parameter i should tune to get the knee point in pybamm better. thanks for the help.

[DrSOKane]

Where does the data labelled "test" come from?

[Thiyaga2025]

@DrSOKane ,

i don't have low current test data now. your suggestion is very valid. the cathode has got a minor blending. will try to get OCV data if that does not work then will try changing diffusivity, etc.,
thanks.

[DrSOKane]

If you don't have any low current test data, try using plot_voltage_components(), like in this notebook.

[Thiyaga2025]

@DrSOKane ,

please let me know your thoughts. thanks.

[DrSOKane]

Looks like the open-circuit potential is the culprit. The OKane2022 parameters are for NMC811, so if you're using a different type of NMC, you will need a different positive electrocde open-circuit potential.

[Thiyaga2025]

@DrSOKane ,

thanks for the valuable insight. will try get the OCV curve for the blend electrode.