A method of monitoring operation of a reactor system includes causing a chemical reaction to occur within an assembly of the reactor system, and measuring a chemical composition of one or more reactants of the chemical reaction with spatial resolution at a plurality of points along a path within the assembly using a sensor system structured to implement distributed sensing. The sensor system includes an optical fiber sensing member provided at least partially within the assembly, wherein the optical fiber sensing member comprises a functionalized optical fiber based sensor device structured to exhibit a change in one or more optical properties in response to changes in the chemical composition of the one or more reactants.

A rechargeable battery assembly for a vehicle has a metal-air rechargeable battery and a filter device to condition inlet air supplied to the metal-air rechargeable battery such that the inlet air exhibits predetermined inlet air values. The filter device has one or more filter elements, one or more sensor devices that determine at least one inlet air parameter, and one or more valve devices. A control system is coupled to the sensor devices so as to receive sensor signals for the at least one inlet air parameter and is coupled to the valve devices. The control system adjusts, depending on the received sensor signals, the valve devices in order to control the predetermined inlet air value in that the inlet air is guided through the filter elements; is guided past the filter elements; or is guided to an air outlet for regenerating the filter elements.

A redox flow battery system includes an anolyte having chromium ions in solution; a catholyte having iron ions in solution, where a molar ratio of chromium in the anolyte to iron in the catholyte is at least 1.25; a first electrode in contact with the anolyte; a second electrode in contact with the catholyte; and a separator separating the anolyte from the catholyte.

An apparatus (10) configured to determine reactant purity comprising: a first fuel cell (11) configured to generate electrical current from the electrochemical reaction between two reactants, having a first reactant inlet (13) configured to receive a test reactant comprising one of the two reactants from a first reactant source (7, 5, 16); a second fuel cell (12) configured to generate electrical current from the electrochemical reaction between the two reactants, having a second reactant inlet (14) configured to receive the test reactant from a second reactant source (5); a controller (20) configured to apply an electrical load to each fuel cell and determine an electrical output difference, OD.sub.t, between an electrical output of the first fuel cell (11) and an electrical output of the second fuel cell (12), and determine a difference between a predicted output difference and the determined electrical output difference, OD.sub.t, the predicted output difference determined based on a historical output of difference and a historical rate of change in said output difference determined at an earlier time, said controller (20) configured to provide a purity output indicative of the test reactant purity at least based on the difference between the predicted and determined output difference.

Systems and methods for managing cathode stoichiometry of an electrochemical cell are disclosed. A system may include a fuel cell, a compressor for supplying air to the fuel cell and an oxygen sensor proximate to or downstream of an outlet of a cathode chamber of the fuel cell. An operation speed of the compressor or flow rate of the air may be adjusted by, for example, a controller after receiving data from the sensor regarding the amount of residual oxygen. For example, the operation speed/flow rate may be increased or decreased to achieve a cathode stoichiometry of about 1.00.

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.

Some embodiments of the disclosure provide a cathode circulation system of a fuel cell connected to a power generation unit of the fuel cell. The cathode circulation system includes a first gas supply tank for providing an inert gas, a second gas supply tank for providing a reaction gas, a mixing tank connected to the first gas supply tank and the second gas supply tank for mixing the inert gas and the reaction gas, a gas-liquid separator connected to the power generation unit, and at least one cathode gas pump provided between the mixing tank and the gas-liquid separator and between the mixing tank and the power generation unit.

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.

An electrochemical cell includes a first hydrogen-rich zone including a cathode, a second hydrogen-poor zone including an anode, an electrical component, and a sorbent configured to capture hydrogen in the second zone and release hydrogen protons into the first zone, an electrolyte located between the cathode and the sorbent, and an electrical circuit arranged to apply voltage bias to remove the captured hydrogen from the sorbent.