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 fuel cell system includes: a fuel cell; an oxidant gas supply unit configured to supply an oxidant gas to a cathode electrode of the fuel cell; and a gas pressure control unit configured to detect as a gas pressure sensitivity a ratio of variation in an output of the fuel cell to variation in the pressure of the oxidant gas, specify a correspondence relationship between the pressure of the oxidant gas and the output of the fuel cell on the basis of the detected gas pressure sensitivity, and control the pressure of the oxidant gas on the basis of the specified correspondence relationship.

A method for supplying at least one fuel cell of a fuel cell system of the motor vehicle with fuel includes ascertaining or predicting an indication value which is indicative of the real and/or possible mass flow of the withdrawal of fuel from a pressure-vessel system of the motor vehicle and closing at least one tank shut-off valve when the indication value is equal to or falls below a limiting value.

A method of cleansing a redox flow battery system may include operating the redox flow battery system in a charge, discharge, or idle mode, and responsive to a redox flow battery capacity being less than a threshold battery capacity, mixing the positive electrolyte with the negative electrolyte. In this way, battery capacity degradation following cyclic charging and discharging of the redox flow battery system can be substantially reduced.

An apparatus is provided for measuring the power of electrolytes at different positions of a flow battery by switching six-way valves without reconnecting channels. With the measurements at the positions, weighting is processed to obtain power corresponding to charging statuses for determining accurate power. The charging and discharging of voltage and current of the battery are controlled for constant operations with high efficiency. Consequently, the efficiency of power conversion is improved; energy consumption is reduced; and the battery is always run within a safe power-range for avoiding accidents or damages to the battery. In addition, the present invention is further applicable to a device monitoring the features of a battery unit. The six-way valves online monitor the power at center positions by switching. The values measured at different positions are aimed at the abnormality of the battery unit for processing adjustment or offline replacement to maintain best operation performance.

The control method for a flow battery includes acquiring a current electrolyte capacity decay rate of the flow battery; comparing the current electrolyte capacity decay rate with a first preset decay rate and a second preset decay rate; when the current electrolyte capacity decay rate is greater than the first preset decay rate and less than the second preset decay rate, adjusting a liquid level of positive electrolyte and a liquid level of negative electrolyte, such that a difference between these two liquid levels is less than a preset value, a ratio of the total amount of vanadium in the positive electrolyte to the total amount of vanadium in the negative electrolyte remains in a first preset ratio range, or a ratio of a vanadium ion concentration in the positive electrolyte to a vanadium ion concentration in the negative electrolyte remains in a second preset ratio range.

A fuel cell system that supplies fuel gas and oxidant gas to a fuel cell stack and causes the fuel cell stack to generate power includes a tank that stores aqueous solution containing oxygen-containing fuel, and a reformer that reforms mixed gas obtained as the aqueous solution is vaporized, and generates the fuel gas. The fuel cell system also includes an actuator that supplies the mixed gas to the reformer, a heating device that heats the reformer, a detecting unit that estimates or detects a concentration of the oxygen-containing fuel in the mixed gas that is supplied to the reformer, and a controller programmed to control operations of the actuator and the heating device so that the fuel cell generates power. The controller is programmed to increase a thermal dose to the reformer from the heating device or reduces a supply amount of the mixed gas to the reformer by the actuator when the concentration of the oxygen-containing fuel is high, compared to when the concentration is low.

A fuel cell system includes: a fuel cell; a voltage regulator that regulates an output voltage of the fuel cell; and a controller configured to perform a refresh process of decreasing the output voltage of the fuel cell to a reduction voltage at which an oxide film formed on the cathode is reduced, by controlling the voltage regulator. The controller, before the refresh process, calculates a first amount, the first amount being an amount by which the oxide film is to be removed from the cathode. The controller determines, as the output voltage of the fuel cell, a refresh voltage that enables the first amount of the oxide film to be removed within a preset reference time. The controller operates the voltage regulator so as to cause the output voltage of the fuel cell to become the refresh voltage when the refresh process is performed.

A benthic microbial fuel cell comprising: a nonconductive frame having an upper end and a lower end; a plurality of anodes, wherein each anode is a conductive plate having a top section and a bottom edge; a plurality of conductive, threaded rods disposed perpendicularly to the anode plates and configured to secure the top sections of the anodes to the lower end of the frame and to hold the plates in a substantially parallel orientation with respect to each other such that none of the plates are in direct contact with each other; and a plurality of cathodes, wherein each cathode is made of carbon cloth connected to the upper end of the frame.

An apparatus for controlling a fuel cell of an environment-friendly vehicle, a system including the same, and a method thereof are provided. The apparatus includes a storage storing information mapping an amount of additional output of a fuel cell according to air density and a current battery state of a high voltage battery depending on a drive mode and a processor that controls an amount of output of the fuel cell in response to a required amount of output of a motor, the amount of output of the fuel cell being varied according to the air density, the current battery state, and the drive mode based on the information mapping the amount of additional output.