Salinic bridges in voltaic cells
A cell has an internal ohmic-equivalent resistance.  The salt bridge is a resistive path for the flow of ions.  Ions, plus their hydration shells and possible coordination shells, have low drift velocities through a medium.  The salt bridge can constrain the ion current of the cell and its material equilibrium rate.  A poor salt bridge by length, diameter, concentration, and permeability will increasingly adversely affect a cell's current and voltage as discharge rate increases.