A method of operating a redox flow battery string including at least first and second redox flow batteries and an outside power source includes: providing a least first and second redox flow batteries in a string electrically connected in a string, and each redox flow battery having a state-or-charge (SOC); obtaining an SOC value for each redox flow battery in the string; identifying a target SOC value in the string; and adjusting the SOC value for at least one of the first and second redox flow batteries to correspond to the target SOC value.

A redox flow battery system includes an anolyte; a catholyte; a first half-cell including a first electrode in contact with the anolyte; a second half-cell including a second electrode in contact with the catholyte; a separator separating the anolyte in the first half-cell from the catholyte in the second half-cell; at least one state measurement device configured for intermittently, periodically, or continuously making a measurement of a value indicative of a state of charge of the anolyte or the catholyte before entering or after leaving the first half-cell or second half-cell, respectively; and a controller coupled to the at least one state measurement device for generating a temporal energy profile of the anolyte or the catholyte, respectively, using the measurements.

One embodiment is a redox flow battery system that includes an anolyte; a catholyte; an anolyte tank configured for holding at least a portion of the anolyte; a catholyte tank configured for holding at least a portion of the catholyte; a primary redox flow battery arrangement, and a second redox flow battery arrangement. The primary and secondary redox flow battery arrangements share the anolyte and catholyte tanks and each includes a first half-cell including a first electrode in contact with the anolyte, a second half-cell including a second electrode in contact with the catholyte, a separator separating the first half-cell from the second half-cell, an anolyte pump, and a catholyte pump. The peak power delivery capacity of the secondary redox flow battery arrangement is less than the peak power delivery capacity of the primary redox flow battery arrangement.

A method for determining a storage capacity or average oxidation state (AOS) of a redox flow battery system including an anolyte and a catholyte includes discharging a portion of the anolyte and catholyte of the redox flow battery system at a discharge rate that is within 10% of a preselected discharge rate; after discharging the redox flow battery system, determining an end OCV; and determining the storage capacity or AOS from the end OCV. Other methods can be used to determine the storage capacity or AOS using a measured OCV.

A redox flow battery system includes an anolyte having a first ionic species in solution; a catholyte having a second ionic species in solution, where the redox flow battery system is configured to reduce the first ionic species in the anolyte and oxidize the second ionic species in the catholyte during charging; a first electrode in contact with the anolyte, where the first electrode includes channels for collection of particles of reduced metallic impurities in the anolyte; a second electrode in contact with the catholyte; and a separator separating the anolyte from the catholyte. A method of reducing metallic impurities in an anolyte of a redox flow battery system includes reducing the metallic impurities in the anolyte; collecting particles of the reduced metallic impurities; and removing the collected particles using a cleaning solution.

A controller of a fuel cell system detects catalytic layer deterioration and drainage malfunction by the following inspection process. The controller may: execute drainage of water from a fuel cell, and acquire first/second output voltages of the fuel cell when an output current density of the fuel cell is a first reference current density A1/A2 (A2>A1). When the first output voltage is lower than a first threshold voltage and the second output voltage is higher than a second threshold voltage, the controller may output a first determination signal indicating that the catalytic layer is deteriorated and the drainage is executed without malfunction. When the first output voltage is higher than the first threshold voltage and the second output voltage is lower than the second threshold voltage, the controller may output a second determination signal indicating that the catalytic layer is not deteriorated and the drainage is executed with malfunction.

A fuel cell system for air vehicles, wherein the fuel cell system comprises: a fuel cell, a fuel gas system for supplying fuel gas to the fuel cell, a potential sensor, and a controller; wherein the fuel gas system comprises a fuel gas supplier; wherein the controller determines whether or not a potential of the fuel cell measured by the potential sensor, is a reversal potential; and wherein, when the controller determines that the potential of the fuel cell is a reversal potential, the controller increases a fuel gas supply from the fuel gas supplier to the fuel cell.

A fuel cell system wherein the fuel cell comprises an electrolyte membrane; wherein the electrolyte membrane is a perfluorosulfonic acid (PFSA) membrane; wherein the controller has a data group showing a correlation between the current of the fuel cell and the temperature of the fuel cell which is necessary to keep a moisture content of the electrolyte membrane at a predetermined moisture content threshold or more; and wherein, when the temperature and voltage of the fuel cell become a predetermined first temperature threshold or more and a predetermined voltage threshold or more, respectively, the controller conducts a temperature dropping time power generation mode in which power generation is conducted while controlling the current of the fuel cell with reference to the data group, until the temperature of the fuel cell becomes a predetermined second temperature threshold which is lower than the first temperature threshold.

An information processing device includes an acquisition unit which acquires use history information indicating a use history of a vehicle, a prediction unit which predicts an output decrease amount of a fuel cell in a vehicle based on the use history information acquired by the acquisition unit and output decrease characteristic information indicating an output decrease characteristic of the fuel cell according to the use history, and a control unit which executes predetermined control based on the output decrease amount predicted by the prediction unit. When the control unit determines that a rated output of the fuel cell is equal to or smaller than a threshold value based on the output decrease amount, the control unit executes adhering substance removal control in which nitrogen-enriched gas having a higher nitrogen concentration and a lower oxygen concentration than air is supplied to the fuel cell as cathode gas.

The invention discloses a method and device for detecting a leakage rate of a solid oxide fuel cell system on line. The method comprises steps of: cutting off fuel gas supply of an anode cavity, cutting off an exhaust line of the anode cavity and cutting off high-pressure air supply of a cathode cavity in the operation process of a solid oxide fuel cell; obtaining an open-circuit voltage and temperature of the solid oxide fuel cell; and determining a leakage rate of the solid oxide fuel cell system according to the open-circuit voltage and the temperature of the solid oxide fuel cell. Based on the technical solutions disclosed by the invention, the leakage rate of the solid oxide fuel cell system can be detected on line.