# US 2014/0152314 A1 · Mass Distribution Indication of Flow Battery State of Charge > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152314 A1 - Document ID: US20140152314A1 - Status: Published application - Kind: A1 - Application number: 14/174,048 - Filed: 2014-02-06 - Published: 2014-06-05 - Earliest claimed: 2012-11-20 - Assignees: Primus Power Corporation - Applicants: Primus Power Corporation - Inventors: Peter Tennessen; Alisa Peterson; Paul Kreiner; Lauren Wessel Hart; Ryan Larsen; Jonathan Hall - Web page: https://patentgrep.com/patent/US20140152314A1 ## CPC - G01R 31/382: Arrangements for monitoring battery or accumulator variables, e.g. SoC - H01M 8/04425: {at auxiliary devices, e.g. reformers, compressors, burners} - H01M 8/04619: {of fuel cell stacks} - H01M 8/188: {by recharging of redox couples containing fluids; Redox flow type batteries} - H01M 8/20: Indirect fuel cells, e.g. fuel cells with redox couple being irreversible (H01M8/18 takes precedence) - H01M 10/4214: {Arrangements for moving electrodes or electrolyte} - H01M 12/06: with one metallic and one gaseous electrode - H01M 50/77: with external circulating path - Y02E 60/10: Energy storage using batteries - Y02E 60/50: Fuel cells - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - 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 An electrochemical device includes at least one electrochemical cell having an anode electrode and a cathode electrode, a reservoir configured to store an electrolyte and a mass distribution measuring device. The mass distribution measuring device includes at least one of a scale, a first pressure sensor located in a lower portion of the reservoir and a second pressure sensor located in an upper portion of the reservoir, or at least one strain gauge or load cell configured to measure a change a weight of the at least one electrochemical cell. ## Claims ### Claim 1 A method of determining the state of charge in a flow battery comprising: measuring a mass distribution characteristic of the flow battery to determine the state of charge, wherein the measuring comprises measuring one or more of: a weight of an electrolyte reservoir; a weight of an electrolyte in the electrolyte reservoir; a pressure difference of an electrolyte between a lower portion of the reservoir and an upper portion of the reservoir; or a weight of a stack of flow battery cells. ### Claim 2 (depends on 1) The method of claim 1, wherein the measuring comprises measuring the weight of the electrolyte reservoir. ### Claim 3 (depends on 1) The method of claim 1, wherein the measuring comprises measuring the weight of the electrolyte in the electrolyte reservoir. ### Claim 4 (depends on 3) The method of claim 3, wherein a portion of a bottom surface of the reservoir comprises a flexible diaphragm located between a scale and the electrolyte. ### Claim 5 (depends on 1) The method of claim 1, wherein the measuring comprises measuring the pressure difference of an electrolyte between a lower portion of the reservoir and an upper portion of the reservoir. ### Claim 6 (depends on 1) The method of claim 1, wherein the method comprises measuring the weight of the stack of flow battery cells. ### Claim 7 (depends on 6) The method of claim 6, wherein measuring the weight of a stack of flow battery cells comprises measuring a change in strain in a stack support with one or more strain gauges or load cells. ### Claim 8 (depends on 1) The method of claim 1, further comprising: performing a calibration step comprising performing an electrical state of charge measurement and then correlating the measured mass distribution characteristic to the electrical state of charge measurement; determining the state of charge during use of the flow battery by determining the state of charge from the mass distribution characteristic using a lookup table, a database or an algorithm. ### Claim 9 (depends on 8) The method of claim 8, wherein the electrical state of charge measurement comprises establishing 0% and 100% state of charge with an open circuit voltage measurement. ### Claim 10 (depends on 1) The method of claim 1, further comprising starting or stopping charge or discharge mode operation of the flow battery based on at least one of the determination of the state of charge or the measurement of the mass distribution characteristic. ### Claim 11 (depends on 1) The method of claim 1, further comprising changing the flow battery from charge mode to discharge mode or from discharge mode to charge mode based on at least one of the determination of the state of charge or the measurement of the mass distribution characteristic. ### Claim 12 (depends on 1) The method of claim 1, further comprising based on at least one of the determination of the state of charge or the measurement of the mass distribution characteristic, performing one or more of: varying a current density in or out of the flow battery; varying a pump speed to vary a bulk electrolyte flow rate into the stack of flow battery cells from a reservoir; varying a complex phase flow rate into the stack of flow battery cells by diverting a complex phase outlet conduit into the stack; or changing a temperature of the electrolyte by changing a setting of a heater or chiller. ### Claim 13 (depends on 1) The method of claim 1, further comprising determining a fault condition based on the measurement of the mass distribution characteristic. ### Claim 14 (depends on 13) The method of claim 13, wherein the fault condition is a leak and the method further comprises issuing a warning or stopping operation of the flow battery. ### Claim 15 (depends on 1) The method of claim 1, further comprising determining an efficiency of the flow battery based on the measurement of the mass distribution characteristic.