Method for operating redox flow battery and redox flow battery cell stack

Abstract

The invention provides an operating method of a redox flow battery capable of grasping a charging state of the battery more reliably to stabilize an output capacity of the battery. The method is for operating the redox flow battery comprising a cell stack 1 comprising a plurality of cells. A selected cell(s) in the cell stack 1 , to and from which positive electrode electrolyte and negative electrode electrolyte are supplied and discharged and which is/are not normally connected to a DC/AC converter 225 , is/are in the form of an auxiliary cell 2 used for measuring a charging rate of the electrolyte. Also, a stop of charge of a main cell 3 and a stop of discharge of the main cell 3 are controlled with reference to a circuit voltage obtained from the auxiliary cell 2 . Since the auxiliary cell 2 is integrally incorporated in the cell stack 1 , the charging state of the battery can be grasped reliably without stopping the charge/discharge operation of the main cell 3 . Also, since the stop of charge of the main cell 3 and the stop of discharge of the same are controlled with reference to the measured circuit voltage, the output capacity can be stabilized.

1 . An operating method of a redox flow battery comprising a cell stack comprising a plurality of cells, 
 wherein at least a part of the cells in the cell stack to and from which positive electrode electrolyte and negative electrode electrolyte are supplied and discharged and which is not normally connected to a DC/AC converter is in the form of an auxiliary cell used for measuring a charging rate of the electrolyte, and    wherein at least either of a stop of charge of the battery and a stop of discharge of the battery is controlled with reference to a circuit voltage obtained from the auxiliary cell.    
     
     
         2 . An operating method of a redox flow battery comprising a cell stack comprising a plurality of cells, 
 wherein at least a part of the cells in the cell stack to and from which positive electrode electrolyte and negative electrode electrolyte are supplied and discharged and which is not normally connected to a DC/AC converter is in the form of an auxiliary cell used for measuring a charging rate of the electrolyte, and    wherein the auxiliary cell is charged or discharged with reference to a circuit voltage obtained from the auxiliary cell, to change a charging rate of the electrolyte.    
     
     
         3 . A cell stack of a redox flow battery, the cell stack comprising a plurality of cells, wherein a main cell, to and from which positive electrode electrolyte and negative electrode electrolyte are supplied and discharged and which is connected to a DC/AC converter, and an auxiliary cell for measuring a charging rate of the electrolyte, which is connected to the main cell in such a manner as to share the electrolytes with the main cell and is not normally connected to a DC/AC converter, are integrally combined with each other.