Raytheon Technologies Corporation

Rtx Corporation

James D Saraidaridis

Robert Mason Darling

Michael L Perry

Zhiwei Yang

Timothy Davenport

In a redox flow battery (RFB), the base solvent of the electrolytes tends to migrate across the barrier layer from one electrode toward the other. This can result in a volume and concentration imbalance between the electrolytes that is detrimental to battery efficiency and capacity. Compatible electrolytes can be mixed to rebalance the system, but for incompatible electrolytes mixing is not a viable option. To this end, the RFB herein includes a separator that recovers base solvent from the vapor phase of one of the electrolytes and returns the recovered base solvent to the other electrolyte to thereby reverse the imbalance.

Condensation-based redox flow battery rebalancing

A redox flow battery includes a redox flow cell and a supply and storage system external of the redox flow cell. The supply and storage system includes first and second electrolytes for circulation through the redox flow cell. The first electrolyte is a liquid electrolyte having electrochemically active manganese species with multiple, reversible oxidation states in the redox flow cell. The electrochemically active manganese species may undergo reactions that cause precipitation of manganese oxide solids. The first electrolyte includes an inhibitor that limits the self-discharge reactions. The inhibitor includes an oxoanion compound.

Alkaline manganese redox flow battery with inhibitor

A redox flow battery system includes a redox flow battery that has a redox flow cell and a supply/storage system. The supply/storage system has first and second electrolytes for circulation through the redox flow cell. At least the first electrolyte is a liquid electrolyte that has electrochemically active species with multiple, reversible oxidation states. A secondary cell is operable to monitor concentration of one or more of the electrochemically active species. The secondary cell has a counter electrode, a flow passage that connects the counter electrode with the redox flow battery to receive the first or second electrolyte, a working electrode, and a separator. The working electrode is isolated from receiving the electrochemically active species of the first and second electrolytes except for a transport passage connecting the flow passage and the working electrode. The transport passage limits movement of the electrochemically active species to the working electrode.

Cell for electrochemically determining active species concentrations in redox flow batteries

A redox flow battery system includes a redox flow battery that has a redox flow cell, and a supply/storage system external of the redox flow cell. The supply/storage system includes first and second electrolytes for circulation through the redox flow cell. At least the first electrolyte is an aqueous liquid electrolyte that has electrochemically active species with multiple, reversible oxidation states. There is a gas vent passage connected with the redox flow battery to receive water byproduct that evolves from side reaction of the first electrolyte. A bypass passage is connected with the supply/storage system to receive the aqueous electrolyte. An electrochemical recovery cell includes a first half-cell connected to the gas vent passage to receive as a reactant the water byproduct and a second half-cell connected to the bypass passage to receive as a reactant the first electrolyte.

Redox flow battery system with electrochemical recovery cell

A method for a redox flow battery includes using a cell of a redox flow battery to store electrical energy and discharge the stored electrical energy. The using includes circulating a first electrolyte solution through a first circulation loop in fluid connection with the first electrode of the cell; circulating a second electrolyte solution through a second circulation loop in fluid connection with the second electrode of the cell; and at least one of a first element from the first electrolyte solution in the first electrode permeates through the separator layer and precipitates as a first solid product in the second electrode and a second element from the second electrolyte solution permeates through the separator layer and precipitates a second solid product in the first electrode. The method also includes removing at least a portion of the first solid product or the second solid product from the first electrode and the second electrode, respectively.

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Hartford, CT, United States of America

James D Saraidaridis