06475661 is referenced by 63 patents.
A redox flow battery composed of a plurality of cells in electrical series defined by a stacked and repetitive arrangement of a conductive intercell separator having a generally bipolar function, a positive electrode, an ion exchange membrane, a negative electrode and another conductive intercell separator, is operated by flowing a positive half-cell electrolyte containing reducible and oxidizable ions of a first redox couple through the compartments containing the positive electrodes and a negative half-cell electrolyte containing reducible and oxidizable ions of a second redox couple through the compartments containing the negative electrodes in cascade in a counter or equi-current mode. The difference of cell voltage between the first and the last cell of the stack is sensibly reduced and by-pass currents are substantially eliminated thus resulting in an increased overall faradic efficiency. A cell stack architecture provided with ducting for implementing the two counter current cascaded flows of the positive and negative electrolytes is described. The alternated used of cationic and anionic membranes compensate for unbalanced water transport through the membranes.