The most established mathematical description of porous battery electrodes is Newman's model, which accounts for the behavior of both solid and liquid phases via concentrated solution theory and porous electrode theory. In the present work, formal volume averaging of reformulated generalized Poisson–Nernst–Planck (PNP) equations in the form of concentration and electrochemical potential, or in the form of equivalent circuit on a representative porous microstructure, lead to “upscaled” equations similar to those in Newman's model. The similarities and differences of the results from the two approaches are discussed throughout the paper.