# US 12,603,305 B2 · Redox flow battery with improved efficiency > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,603,305 B2 - Document ID: US12603305B2 - Status: Granted - Kind: B2 - Application number: 17/119,408 - Filed: 2020-12-11 - Published: 2022-06-16 - Granted: 2026-04-14 - Earliest claimed: 2020-12-11 - Assignees: Rtx Corporation - Applicants: Raytheon Technologies Corporation - Inventors: James D. Saraidaridis; Zhiwei Yang - Web page: https://patentgrep.com/patent/US12603305B2 ## CPC - H01M 8/04186: of liquid-charged or electrolyte-charged reactants - H01M 8/04201: {Reactant storage and supply, e.g. means for feeding, pipes} - H01M 8/043: applied during specific periods - H01M 8/04664: Failure or abnormal function - H01M 8/04776: {at auxiliary devices, e.g. reformer, compressor, burner} - H01M 8/188: {by recharging of redox couples containing fluids; Redox flow type batteries} - Y02E 60/50: Fuel cells - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A method for maintaining a redox flow includes draining a first battery electrolyte solution from a redox flow battery cell, the cell including a separator layer arranged between a first electrode and a second electrode, a first circulation loop configured to provide the first battery electrolyte solution to the first electrode and a second circulation loop configured to provide a second battery electrolyte solution to the second electrode; and flowing a non-battery electrolyte solution through the first electrode. The non-battery electrolyte removes at least a portion of the solid precipitates from at least one of the first electrode and the separator layer. The method also includes draining the non-battery electrolyte solution from the cell and returning the first battery electrolyte solution to the cell. A method for a redox flow battery and a redox flow battery are also disclosed. ## Claims ### Claim 1 A method for maintaining a redox flow battery, comprising: draining a first battery electrolyte solution from a redox flow battery cell, the cell including a separator layer arranged between a first electrode and a second electrode, a first circulation loop configured to provide a first battery electrolyte solution to the first electrode and a second circulation loop configured to provide a second battery electrolyte solution to the second electrode; flowing a non-battery electrolyte solution through the first electrode, whereby the non-battery electrolyte solution removes at least a portion of solid precipitates from at least one of the first electrode and the separator layer, wherein the non-battery electrolyte solution includes at least one active species that is chemically reactive with respect to the solid precipitates such that the reaction production is a gas; draining the non-battery electrolyte solution from the cell; and returning the first battery electrolyte solution to the cell. ### Claim 2 (depends on 1) The method of claim 1, wherein the non-battery electrolyte solution removes the solid precipitates from the cell by carrying the solid precipitates out of the cell. ### Claim 3 (depends on 1) The method of claim 1, wherein the non-battery electrolyte solution removes solid precipitates from the cell by dissolving the solid precipitates. ### Claim 4 (depends on 1) The method of claim 1, wherein the non-battery electrolyte solution includes at least one species that is active with respect to the solid precipitates, and wherein the activity between the solid precipitates and the at least one species removes the solid precipitates from the cell. ### Claim 5 (depends on 4) The method of claim 4, wherein the solid precipitates include at least one metal, and wherein the at least one active species includes chelating agent, the chelating agent facilitating the removal of the metal solid precipitates from the cell. ### Claim 6 (depends on 1) The method of claim 1, wherein the reaction product is one of the product of a reduction reaction and the product of an oxidation reaction. ### Claim 7 (depends on 1) The method of claim 1, further comprising venting the gas. ### Claim 8 (depends on 1) The method of claim 1, wherein the non-battery electrolyte solution has a common solvent with at least one of the first battery electrolyte solution. ### Claim 9 (depends on 1) The method of claim 1, wherein the non-battery electrolyte solution does not include any active species from the first battery electrolyte solution. ### Claim 10 (depends on 1) The method of claim 1, further comprising determining an amount of solid precipitates in the cell prior to the draining step, and comparing the amount of solid precipitates to a predetermined threshold amount of solid precipitates. ### Claim 11 (depends on 1) The method of claim 1, further comprising flowing the non-battery electrolyte solution through the second electrode, whereby the non-battery electrolyte removes the solid precipitates from the second electrode. ### Claim 12 A method for a redox flow battery, the method comprising: using a cell of a redox flow battery to store input electrical energy upon charging and releasing the stored electrical energy upon discharging, wherein the cell has a separator layer arranged between a first electrode and a second electrode, and wherein 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 wherein at least one reaction product precipitates as a solid precipitate in the second electrode; and removing at least a portion of the solid product from at least one of the second electrode and the separator layer by flowing a non-battery electrolyte solution through the second electrode, wherein the non-battery electrolyte solution includes at least one species that is that is chemically reactive with respect to the solid precipitate such that the reaction product is a gas, and wherein the gas is removed from the cell. ### Claim 13 (depends on 12) The method of claim 12, wherein the at least one active species includes a species that is chemically reactive with respect to the solid precipitates such that the reaction product of the component and the solid precipitates is soluble in the non-battery electrolyte solution. ### Claim 14 (depends on 12) The method of claim 12, wherein the solid product is one of the product of a reaction between an element of the first electrolyte and an element of the second electrolyte and the product of a side reaction between two elements of the second electrolyte. ### Claim 15 A redox flow battery comprising: a cell having a first electrode and a second electrode and a separator layer arranged between the first and second electrodes; a first circulation loop fluidly connected with the first electrode; a first battery electrolyte solution contained in the first circulation loop; a second circulation loop fluidly connected with the second electrode; a second battery electrolyte solution contained in the second circulation loop; a third circulation loop fluidly connected to the first electrode, second electrode or both; and a non-battery electrolyte solution contained in the third circulation loop, the non-battery electrolyte solution including at least one species that is chemically reactive with solid precipitates such that the reaction product is a gas and such that the non-battery electrolyte solution is operable to remove at least a portion of the solid precipitates from at least one of the first electrode, the second electrode, and the separator layer.