A redox flow battery system includes a redox flow battery that has a redox flow cell and a supply/storage system. The supply/storage system has first and second electrolytes for circulation through the redox flow cell. At least the first electrolyte is a liquid electrolyte that has electrochemically active species with multiple, reversible oxidation states. A secondary cell is operable to monitor concentration of one or more of the electrochemically active species. The secondary cell has a counter electrode, a flow passage that connects the counter electrode with the redox flow battery to receive the first or second electrolyte, a working electrode, and a separator. The working electrode is isolated from receiving the electrochemically active species of the first and second electrolytes except for a transport passage connecting the flow passage and the working electrode. The transport passage limits movement of the electrochemically active species to the working electrode.

A redox flow battery system with a redox flow battery includes a redox flow cell, and a supply/storage system external of the redox flow cell. The supply/storage system includes first and second electrolytes for circulation through the redox flow cell. At least the first electrolyte is a liquid electrolyte that has electrochemically active species with multiple, reversible oxidation states. A secondary cell is fluidly connected with the first electrolyte and is operable to monitor concentration of one or more of the electrochemically active species. The secondary cell includes a counter electrode, a working microelectrode, and an ionically conductive path formed by the first electrolyte between the counter electrode and the working microelectrode.

A hybrid redox fuel cell system includes a hybrid redox fuel cell including an anode side through which a reductant is flowed and a cathode side through which liquid electrolyte is flowed, and a catalyst bed fluidly connected to the cathode side of the hybrid redox fuel cell, the catalyst bed including a substrate layer and a catalyst layer spiral wound into a jelly roll structure. Furthermore, the liquid electrolyte includes a metal ion at a higher oxidation state and the metal ion at a lower oxidation state, and power is generated at the hybrid redox fuel cell by way of reducing the metal ion from the higher oxidation state to the lower oxidation state at the cathode side while oxidizing the reductant at the anode side.

A redox flow battery includes a tank configured to store an electrolyte and a distribution mechanism to distribute the electrolyte to a battery cell. The tank has a partition portion partitioning a space inside the tank into a first space and a second space, the distribution mechanism has a distribution passage through which the electrolyte is distributed between the first space and the second space via the battery cell, and the partition portion is composed of a flexible material.

Liquid membrane cell assemblies are disclosed. In some embodiments, the liquid membrane cell assembly includes an elongate base having opposed first and second end portions and a central portion disposed therebetween. The first and second end portions each includes an elongate body, an electrolyte channel within the body, an electrolyte port fluidly connected to the electrolyte channel, a fuel channel within the body, and a fuel port fluidly connected to the fuel channel. The central portion includes spaced and opposed first and second members that connect the bases of the first and second portions and that horizontally define an open area therebetween. The liquid membrane cell assembly additionally includes an anode adjacent the first and second members, and a cathode adjacent the first and second members such that the base is disposed between the anode and the cathode. The anode and cathode vertically define the open area therebetween.

A redox flow battery includes a tank configured to store an electrolyte and a distribution mechanism to distribute the electrolyte to a battery cell. The tank has a partition portion partitioning a space inside the tank into a first space and a second space, the distribution mechanism has a distribution passage through which the electrolyte is distributed between the first space and the second space via the battery cell, and the partition portion is composed of a flexible material.

The invention provides a membrane-free redox cell utilizing auxiliary electrodes that facilitate fast charging and discharging of anolyte and catholyte for electrochemical energy storage. The anode and cathode chambers are ionically separated, and electrically connected through a conductor joining auxiliary electrodes comprised of a redox material. In use, charging/discharging of the galvanic cell takes place between primary electrodes, and the redox material is immersed in the electrolyte in both anode and cathode chambers.

A method and apparatus for comparing fuel sources to assess the suitability of a fuel for use in a fuel cell. The apparatus comprising an electrochemical sensor comprising a fuel flow channel configured to receive a plurality of input fuels at a plurality of locations along the fuel flow channel. The fuel flow channel configured to supply the plurality of input fuels to an anode of the electrochemical sensor and an electrolyte configured to transmit ionised input fuels from the anode to a cathode of the electrochemical sensor. A control system connected to the electrochemical sensor where the anode and/or the cathode is divided into a plurality of segments and the control system is configured to measure the current in each of the plurality of segments and determine the current density of each of the plurality of segments.

A redox flow battery includes a battery cell to which a positive electrolyte and a negative electrolyte are supplied, and an electrical quantity measurement system configured to measure a quantity of electricity when a predetermined amount of electrolyte is discharged, for at least one of the positive electrolyte and the negative electrolyte. The electrical quantity measurement system includes an electrolytic cell having a working electrode to which one of the positive electrolyte and the negative electrolyte, in which the quantity of electricity is to be measured, is supplied, and a counter electrode to which the other electrolyte, which is not to be measured, is supplied; a standard electrode disposed, outside the electrolytic cell, so as to be in contact with the one electrolyte to be measured; and a measurement device configured to apply, to the electrolytic cell, a voltage that is set on the basis of a potential of the standard electrode and capable of performing total electrolysis of the one electrolyte contained in the working electrode and measure the quantity of electricity of the one electrolyte.

The invention provides a membrane-free redox cell utilizing auxiliary electrodes that facilitate fast charging and discharging of anolyte and catholyte for electrochemical energy storage. The anode and cathode chambers are ionically separated, and electrically connected through a conductor joining auxiliary electrodes comprised of a redox material. In use, charging/discharging of the galvanic cell takes place between primary electrodes, and the redox material is immersed in the electrolyte in both anode and cathode chambers.