The electrolyte properties are important parameters in the mechanical model; the density
indicates its inertia, or resistance to an accelerating force, and the viscosity describes its fluidity,it may be thought of as internal friction between the molecules. They are both related to the
attraction forces between the particles; thus they depend on the electrolyte composition.
The VRB electrolytes are composed of vanadium ions dissolved in sulphuric acid; we have
seen previously that their composition changes as the battery is operating (see Fig. 3).
Therefore, the electrolyte properties must change accordingly to the composition; but for
simplicity reasons, these properties are maintained constant in this work. Tab. 5 gives the
density and the viscosity for some vanadium solutions.