I fully understand how standard CC/CV charging works. Not asking that

Yes you are asking" that" & you do not completely understand, in order for the charging phases, that is, trickle charge, constant current ,constant voltage, are implemented you must take into consideration the simultaneous effects of charging factors, such as (SOC) state of charge , (SOH) state of health , (SEI) solid electrolyte interface, C-rate, and rest period is essential. the SOC on the ohmic resistance and the cathodic charge transfer resistance depends on the C-rate. The charge-transfer processes, both from the electrolyte into the SEI and from the SEI into the active material of the anode/ cathode,

it is important to take into account that a battery is a nonlinear, time-invariant system, and therefore a long rest time is needed to ensure that the battery is in electrochemical equilibrium

Electrochemical impedance spectroscopy has long been used to characterize the condition of a battery and for the description of the electrochemical characteristics.

That's what impedance is.........AC resistance

I like using the imaginary numbers with my impedance measurements