# US 8,785,023 B2 · Cascade redox flow battery systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,023 B2 - Document ID: US8785023B2 - Status: Granted - Kind: B2 - Application number: 12/986,892 - Filed: 2011-01-07 - Published: 2011-09-15 - Granted: 2014-07-22 - Earliest claimed: 2008-07-07 - Assignees: Enervault Corparation - Applicants: Craig R. Horne; Kim Kinoshita; Darren B. Hickey; Jay E. Sha; Deepak Bose - Inventors: Craig R. Horne; Kim Kinoshita; Darren B. Hickey; Jay E. Sha; Deepak Bose - Web page: https://patentgrep.com/patent/US8785023B2 ## CPC - H01M 8/20: Indirect fuel cells, e.g. fuel cells with redox couple being irreversible (H01M8/18 takes precedence) - B60L 50/64: Constructional details of batteries specially adapted for electric vehicles - B60L 53/30: Constructional details of charging stations - B60L 53/51: Photovoltaic means - B60L 53/52: Wind-driven generators - B60L 53/53: Batteries - B60L 53/54: Fuel cells - H01M 6/188: {Processes of manufacture} - H01M 8/188: {by recharging of redox couples containing fluids; Redox flow type batteries} - B60L 2210/40: DC to AC converters - H01M 50/77: with external circulating path - Y02E 60/50: Fuel cells - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - Y02T 10/7072: Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors - Y02T 10/72: Electric energy management in electromobility - Y02T 90/12: Electric charging stations - Y02T 90/14: Plug-in electric vehicles - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A reduction/oxidation (“redox”) flow battery system includes a series of electrochemical cells arranged in a cascade, whereby liquid electrolyte reacts in a first electrochemical cell (or group of cells) before being directed into a second cell (or group of cells) where it reacts before being directed to subsequent cells. The cascade includes 2 to n stages, each stage having one or more electrochemical cells. During a charge reaction, electrolyte entering a first stage will have a lower state-of-charge than electrolyte entering the nth stage. In some embodiments, cell components and/or characteristics may be configured based on a state-of-charge of electrolytes expected at each cascade stage. Such engineered cascades provide redox flow battery systems with higher energy efficiency over a broader range of current density than prior art arrangements. ## Claims ### Claim 1 A redox flow battery energy storage system, comprising: a first redox flow battery cell block; and a second redox flow battery cell block, the first redox flow battery cell block having an outlet fluidically coupled to an inlet of the second redox flow battery cell block, wherein the first cell block has a first structural configuration based on a first state-of-charge range and the second cell block has a second structural configuration different from the first structural configuration, the second structural configuration based on a second state-of-charge range that is different from the first state of charge range. ### Claim 2 A redox flow battery energy storage system, comprising: a first redox flow battery cell block configured to operate at a first state of charge range, the first redox flow battery cell block comprising: a first plurality of cells each of which has at least one of: a first structural property and a first material property, the at least one of the first structural property and the first material property based on the first state of charge range; and a second redox flow battery cell block configured to operate at a second state of charge range different than the first state of charge range, and comprising a second plurality of cells each of which has at least one of: a second structural property and a second material property, the at least one of the second structural property and the second material property based on the second state of charge range, the at least one of: the second structural property and the second material property being different from the at least one of: the first structural property and the first material property, wherein the first redox flow battery cell block is fluidically coupled in a cascade arrangement along a reactant flow path to the second redox flow battery cell block. ### Claim 3 A redox flow battery energy storage system, comprising: a plurality of redox flow battery cell blocks fluidically coupled together in fluidic series to form a reactant flow path, an outlet of a first of the plurality of cell blocks coupled to an inlet of a second one of the plurality of cell blocks along the reactant flow path, the plurality of cell blocks operating according to the same one of: a charge mode and a discharge mode; wherein: each of the redox flow battery cell blocks comprises a plurality of cells, each of the cell blocks has a physical configuration according to a state of charge of reactant in the respective cell blocks; the first one of the plurality cell blocks has a first physical configuration according to a first state of charge range; the second one of the plurality of cell blocks has a second physical configuration according to a second state of charge range; the first state of charge range and the second state of charge range are different; and the first physical configuration of the first one of the plurality of cell blocks and the second physical configuration of the second one of the plurality of cell blocks are different. ### Claim 4 (depends on 3) The redox flow battery energy storage system of claim 3, wherein the plurality of redox flow battery cell blocks are fluidically coupled together so that reactant flows through each of the plurality of redox flow battery cell blocks one at a time. ### Claim 5 (depends on 4) The redox flow battery energy storage system of claim 4, wherein: the plurality of redox flow battery cell blocks are fluidically coupled together so that reactant separates to flow in parallel through the plurality of cells in each redox flow battery cell block and remixes between each of the plurality of redox flow battery cell blocks. ### Claim 6 (depends on 5) The redox flow battery energy storage system of claim 5, wherein each of the plurality of redox flow battery cell blocks further comprises a plurality of shunt breakers arranged between at least some of the plurality of cells in each redox flow battery cell block. ### Claim 7 (depends on 5) The redox flow battery energy storage system of claim 5, further comprising a plurality of inter-stage components fluidically coupled between each of the plurality of redox flow battery cell blocks. ### Claim 8 (depends on 7) The redox flow battery energy storage system of claim 7, wherein the plurality of inter-stage components comprises a plurality of shunt breakers configured to reduce shunt currents flowing in the plurality of redox flow battery cell blocks. ### Claim 9 (depends on 8) The redox flow battery energy storage system of claim 8, wherein the plurality of shunt breakers comprise a peristaltic pump. ### Claim 10 (depends on 7) The redox flow battery energy storage system of claim 7, wherein the plurality of inter-stage components comprises a plurality of sensors. ### Claim 11 (depends on 10) The redox flow battery energy storage system of claim 10, wherein the plurality of sensors includes sensors selected from the group comprising state-of-charge sensors, electrical current sensors, electrical resistance sensors, volt meters, density sensors, spectroscopic sensors, OCV sensors, reactant balance sensors, flow meters, and pressure sensors. ### Claim 12 (depends on 7) The redox flow battery energy storage system of claim 7, wherein the plurality of inter-stage components comprises a plurality of valves. ### Claim 13 An electrical power system, comprising: a source of electrical power; and a redox flow battery system configured to receive electrical power from the source of electrical power and provide electrical power to an electrical load, the redox flow battery system comprising: a plurality of redox flow battery cell blocks fluidically coupled together in fluidic series to form a reactant flow path, an outlet of a first of the plurality of cell blocks coupled to an inlet of a second one of the plurality of cell blocks along the reactant flow path, the plurality of cell blocks operating according to the same one of: a charge mode and a discharge mode; wherein: each of the redox flow battery cell blocks comprises a plurality of cells, each of the cell blocks has a physical configuration according to a state of charge of reactant in the respective cells blocks; the first one of the plurality cell blocks has a first physical configuration according to a first state of charge range; the second one of the plurality of cell blocks has a second physical configuration according to a second state of charge range; the first state of charge range and the second state of charge range are different; and the first physical configuration of the first one of the plurality of cell blocks and the second physical configuration of the second one of the plurality of cell blocks are different. ### Claim 14 (depends on 13) The electrical power system of claim 13, wherein the plurality of redox flow battery cell blocks are fluidically coupled together so that reactant flows through each of the plurality of redox flow battery cell blocks one at a time. ### Claim 15 (depends on 14) The electrical power system of claim 14, wherein: the plurality of redox flow battery cell blocks are fluidically coupled together so that reactant separates to flow in parallel through the plurality of cells in each redox flow battery cell block and remixes between each of the plurality of redox flow battery cell blocks. ### Claim 16 (depends on 15) The electrical power system of claim 15, wherein each of the plurality of redox flow battery cell blocks further comprises a plurality of shunt breakers arranged between at least some of the plurality of cells in each redox flow battery cell block. ### Claim 17 (depends on 15) The electrical power system of claim 15, further comprising a plurality of inter-stage components fluidically coupled between each of the plurality of redox flow battery cell blocks. ### Claim 18 (depends on 17) The electrical power system of claim 17, wherein the plurality of inter-stage components comprises a plurality of shunt breakers configured to reduce shunt currents flowing in the plurality of redox flow battery cell blocks. ### Claim 19 (depends on 18) The electrical power storage system of claim 18, wherein the plurality of shunt breakers comprise a peristaltic pump. ### Claim 20 (depends on 17) The electrical power system of claim 17, wherein the plurality of inter-stage components comprises a plurality of sensors. ### Claim 21 (depends on 20) The electrical power system of claim 20, wherein the plurality of sensors includes sensors selected from the group comprising state-of-charge sensors, electrical current sensors, electrical resistance sensors, volt meters, density sensors, spectroscopic sensors, OCV sensors, reactant balance sensors, flow meters, and pressure sensors. ### Claim 22 (depends on 17) The electrical power system of claim 17, wherein the plurality of inter-stage components comprises a plurality of valves.