Initial Values
The Initial Values node sets the initial values for the electrolyte potential, the electric potential, and the electrolyte salt concentration. Use multiple Initial Values nodes to specify different initial values in different domains.
For many electrochemical problems that use nonlinear electrode kinetics, such as Butler-Volmer kinetics, providing reasonable initial values can significantly improve solver convergence.
A good value for the Electric potential (SI unit: V) in electrode and porous electrode domains can usually be derived from the boundary conditions. For instance, if a boundary has been grounded or set to a cell potential, use that value as the initial value also in the adjacent domain. For the Electrolyte potential (SI unit: V) a good initial value is often the negative of the equilibrium potential of the grounded electrode.
The default initial Electrolyte salt concentration, 4900 mol/m3, is a typical value for a standard lead-acid battery.
The initial value of the Porosity (dimensionless) will set the initial electrode state-of-charge (SOC) in the Negative Porous Electrode and Positive Porous Electrode nodes.