The RC model is based on Reference [1], where the battery parameters are derived from the author’s tests on several TCL PL-383562 polymer Li-Ion batteries.
Since the R and RC models referenced in that application note align well, I assume that the R model parameters were extracted from the charge curve of that battery using the procedures outlined in the paper behind the R model [2].
Min Chen and G. A. Rincon-Mora, “Accurate electrical battery model capable of predicting runtime and I-V performance,” in IEEE Transactions on Energy Conversion, vol. 21, no. 2, pp. 504-511, June 2006, doi: 10.1109/TEC.2006.874229.
O. Tremblay, L. Dessaint and A. Dekkiche, “A Generic Battery Model for the Dynamic Simulation of Hybrid Electric Vehicles,” 2007 IEEE Vehicle Power and Propulsion Conference, 2007, pp. 284-289, doi: 10.1109/VPPC.2007.4544139.