An electric power supply device supplies electric power to a work machine having an electric power source. The electric power supply device includes a fuel cell different from the electric power source and an electric power connecting section for transferring electric power between the electric power source and the electric power supply device. A control device for controlling the electric power supply device includes a rated capability obtaining section for obtaining the information indicating the rated value of the charge and discharge capability of the electric power source of the work machine in response to the electric power supply device being mounted in the work machine or the electric power supply device being able to utilize the electric power of the electric power source, and an operating condition determining section for determining the operating condition of the electric power supply device based on the rated value.

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.

A coolant control system of a fuel cell may include the fuel cell; a coolant line allowing a coolant to circulate therein and connected to the fuel cell to be heat-exchangeable with the fuel cell; an ion removal line provided with an ion filter and connected to a first portion and a second portion of the coolant line to allow a coolant branched from the first portion of the coolant line to pass through the ion filter and then flow into the second portion of the coolant line again; an adjusting valve adjusting a ratio between coolants respectively flowing into the coolant line and the ion removal line; and a controller engaged to the adjusting valve and configured for controlling the adjusting valve based on a temperature of the fuel cell or an output voltage of the fuel cell.

A fuel cell system includes fuel cell, electrical storage device that stores electric power generated by the fuel cell, and control device of the fuel cell, the control device performs first control which causes the fuel cell to generate power and increases charging rate of the electrical storage device and second control which restricts output of the fuel cell to be smaller than that in the first control and decreases charging rate of the electrical storage device, and when switching condition, in which electric power demand from the external devices becomes greater than predetermined electric power or state in which electric power demand from the external devices is greater than the predetermined electric power continues for predetermined time, is satisfied, the control device increases power output by the fuel cell during the first control being performed to be larger than that before the switching condition was satisfied.

A redox flow battery system (10) comprises an electrochemical cell (11) divided into first and second compartments (11a, 11b) by a porous membrane (13). Each of the first and second compartment (11a, 11b) houses an electrode. An electrolyte storage tank (14) has a first volume (14a) and a second volume (14b) separated from the first volume by a movable separator (15). The first volume (14a) of the storage tank (14) is in fluid communication with the first compartment (11a) and the second volume (14b) of the storage tank (14) is in fluid communication with the second compartment (11b). The system (10) also includes a flow control system configured to move fluid between the first volume (14a) of the storage tank and the second volume (14b) of the storage tank through the first and second compartments (11a, 11b) of the electrochemical cell (11). An associated method is also described.

A fuel cell system includes: a fuel cell stack; a first cooling medium circuit through which a cooling medium for cooling the fuel cell stack flows; an ion exchanger that removes ions in the cooling medium; a second cooling medium circuit in which the average ion concentration of the cooling medium is lower than that of the cooling medium in the first cooling medium circuit; a switching valve that switches between a flow state and a low flow state; a pump configured to cause the cooling medium in the second cooling medium circuit to flow into the first cooling medium circuit; and a control unit that, when a stop period of the fuel cell system is longer than a reference period, drives the pump with the switching valve switched to the flow state after the instruction to start the fuel cell system is input.

A power supply device includes a power supply, a conversion unit performing voltage conversion on electric power to be supplied from the power supply, and a control unit generating a first control signal for inputting or outputting a target voltage or a target current to and from the conversion unit by a feedback loop, and controlling the conversion unit based on the first control signal and a second control signal for detecting a state of the power supply, generated outside the feedback loop. The control unit sets a specific parameter of the second control signal based on a feedforward term based on the output of the power supply and a feedback term in which the specific parameter included in at least one of electric power output from the power supply and input into the conversion unit and electric power output from the conversion unit, is a feedback component.

A method includes selecting a test waveform to inject to a battery from a first DC converter, determining a first resulting ripple that will be generated in response to injecting the test waveform, determining at least one offset waveform to inject to at least one second DC power source from at least one second DC converter such that one or more second ripples will be provided that will cancel the first resulting ripple if the battery is charging, injecting the test waveform to the battery, injecting the at least one offset waveform to the at least one second DC power source, determining if the first resulting ripple has been cancelled, and determining if the battery is charging or discharging based on the step of determining if the first resulting ripple has been cancelled.

A fuel cell system includes: a low-frequency superimposition section superimposing a the low-frequency signal on a fuel cell; and an impedance computation section configured to compute low-frequency impedance of the fuel cell at a time when the low-frequency superimposition section superimposes the low-frequency signal on the fuel cell. The fuel cell system includes: a diagnosing section diagnosing a degree of dryness inside the fuel cell on the basis of low-frequency impedance; and an oxidant gas amount adjustment section configured to adjust an amount of oxidant gas in the fuel cell. The diagnosing section is configured to diagnose the degree of dryness inside the fuel cell on the basis of the low-frequency impedance when the oxidant gas amount adjustment section adjusts the amount of the oxidant gas to be equal to or smaller than a reference gas amount.

A fuel cell system, comprising: a fuel cell stack including a stacked body provided by stacking a plurality of cells in a stacking direction; a compressor configured to feed a purge gas to a cathode of the fuel cell stack; a controller configured to control the compressor, such as to perform stop-time purging that purges the cathode of the fuel cell stack when operation of the fuel cell system is stopped; a first temperature gauge configured to measure a first temperature value that reflects temperature of a cell placed near a center in the stacking direction among the plurality of cells constituting the stacked body and to input the measured first temperature value into the controller; and a second temperature gauge configured to measure a second temperature value that reflects temperature of a cell placed near an end in the stacking direction among the plurality of cells constituting the stacked body and to input the measured second temperature value into the controller, wherein the controller is configured to suspend the stop-time purging when the first temperature value is equal to or higher than a first reference temperature and the second temperature value is lower than a second reference temperature.