ESTIMATION OF THE STATE OF CHARGE OF A POSITIVE ELECTROLYTE SOLUTION OF A WORKING REDOX FLOW BATTERY CELL WITHOUT USING ANY REFERENCE ELECTRODE

摘要

A Method and device for measurement is disclosed in operation, an undivided cell sensor immersed at any desirable point of the positive electrolyte circuit is constantly supplied at a controlled fixed DC bias voltage between the positive metal electrode and the porous carbon counter-electrode by an appropriate voltage regulator of adequate power capability, or cyclically at two or more different voltages, all within a range that includes the region between 0.35V and 0.45V, measuring simultaneously the current flowing across the undivided cell sensor at the fixed voltage or voltages bias. By correlating the paired voltage and current values, using a look up table compiled at calibration, estimated values of the degree of oxidation or state of charge of the redox ion couple of the positive electrolyte solution are produced.

主权项

1. A method of instrumental assessment of the degree of oxidation or state of charge of a positive electrolyte solution containing a V+4/V+5 redox ion couple of a working redox flow battery cell, comprising:
a) procuring a undivided cell assembly comprising a stable electro catalytic metal electrode and a porous carbon counter-electrode similar to the porous carbon electrodes employed in the battery cell, immersed in the positive electrolyte circulating in a positive electrolyte solution flow compartment of the battery cell, the degree of oxidation of its redox couple or state of charge of which must be assessed; b) supplying the two electrodes of the test cell at a positive regulated DC voltage between said stable electro catalytic metal electrode and said porous carbon counter-electrode and measuring the current flowing through said undivided cell at one or several different regulated DC supply voltages in a range comprising the interval from 0.35V and 0.45V; and c) producing an estimated value of the degree of oxidation or state of charge of the positive electrolyte solution from at least a pair of measured voltage and current values within the region on a Cartesian voltage-current plane defined by said voltage interval.