A fuel cell system comprises: a fuel cell stack; a turbo compressor configured to supply a cathode gas to the fuel cell stack through a cathode gas supply line; a pressure regulation valve configured to regulate a pressure of the cathode gas; and a controller, wherein the controller is configured to calculate a target rotation speed of the turbo compressor and a target opening position of the pressure regulation valve, based on a target flow rate of the cathode gas and a target pressure of the cathode gas that are determined according to a required power output of the fuel cell stack and to control the turbo compressor and the pressure regulation valve using the calculated target rotation speed and the calculated target opening position, and the controller is configured, upon increase of the required power output, to: (a) determine an acceptable overshoot level of a flow rate of the cathode gas that is to be supplied to the fuel cell stack, the acceptable overshoot level being selected from a plurality of levels based on at least an increased amount of the required power output; and (b) set a time change in opening position of the pressure regulation valve such that an overshoot amount in a change of the flow rate of the cathode gas becomes smaller as the acceptable overshoot level gets lower, and perform control of the pressure regulation valve. This configuration suppresses an excessive overshoot in the flow rate of the cathode gas.

An alternating current (AC) impedance spectroscopy method includes providing an AC impedance spectroscopy ripple from power electronics into an electrochemical device, and absorbing the ripple in the power electronics.

An energy conversion arrangement configured to convert chemical energy into electrical energy. The energy conversion arrangement comprises plural cell groups 30, 32, 34, 36, each cell group being configured to convert chemical energy into electrical energy. The energy conversion arrangement also comprises at least one measurement arrangement 38, 40, 42, 44, 46 configured to make measurements at each of the plural cell groups 30, 32, 34, 36. Each energy conversion arrangement is configured to determine a condition of at least one of: each of the plural cell groups; and the energy conversion arrangement. The condition is determined in dependence on the measurements made at each cell group and a model of each cell group.

An output performance diagnosis apparatus for a fuel cell acquires, in a case where determination is made that a representative value of impedance of the fuel cell acquired during a trip of a vehicle traveling with a fuel cell as a power source is equal to or less than an impedance threshold, during the trip in which the impedance is acquired, a current-voltage characteristic of the fuel cell based on a change of an output voltage of the fuel cell after a period in which the output voltage of the fuel cell is maintained in a range equal to or higher than a lower limit voltage and equal to or lower than a voltage threshold higher than the lower limit voltage over a predetermined period or more, and calculates maximum output electric power of the fuel cell based on the acquired current-voltage characteristic.

A fuel cell system that includes a fuel cell body that is formed by a membrane electrode assembly including an anode catalyst and a cathode catalyst between which an electrolyte membrane is sandwiched and a pair of separators forming an anode-catalyst-side flow channel and a cathode-catalyst-side flow channel, a fuel supply system configured to supply fuel gas to the fuel cell body, an oxidant supply system configured to supply oxidant gas to the fuel cell body, a control device that controls these supply systems in accordance with an operating state of the fuel cell system and a catalyst deterioration recovery device that recovers deterioration of the anode catalyst. The catalyst deterioration recovery device includes a plurality of catalyst deterioration recovery means, a specific operating state detecting means configured to detect a specific operating state of the fuel cell system and a selecting means configured to selectively activate the plurality of catalyst deterioration recovery means in accordance with the specific operating state.

A system and a method for measuring impedance of a fuel cell stack are disclosed. The system includes: an energy consumption device, a cooling device, and a high-voltage battery connected in parallel to a main bus end of a fuel cell stack; a relay provided at the main bus end and configured to electrically connect or disconnect the cooling device and the high-voltage battery to or from the fuel cell stack; an impedance measurement unit configured to apply an AC current to the fuel cell stack and to measure the impedance of the fuel cell stack; and a controller configured to turn off the relay during measurement of the impedance of the fuel cell stack.

When a time point of occurrence of a stop state of a fuel cell system is predicted during traveling, a drying state control that causes a fuel cell stack to transition to a dry state is started a predetermined time (a required drying time) before the predicted time point of occurrence of the stop state.

The present disclosure is directed, in certain embodiments, to a flow cell battery system. A battery management system detects that a first power module and a second power module located adjacent to the first power module are operating at different states of charge. After determining that the second power module is at the lower state of charge than the first power module, a negative-side switch associated with the second power module is adjusted to an open position, thereby preventing flow of electrical current from a negative terminal of the second power module to electrical ground.

Systems, methods, and devices of the various embodiments provide a hardware and software architecture enabling electrochemical impedance spectroscopy (“EIS”) to be performed on multiple electrochemical devices, such as fuel cells, at the same time without human interaction with the electrochemical devices and to use EIS to dynamically monitor the performance of a fuel cell system. Embodiment methods may include determining an impedance of a set of fuel cells using electrochemical impedance spectroscopy, determining an ohmic polarization of the set of fuel cells from the impedance, determining a concentration polarization of the set of fuel cells from the impedance, comparing the ohmic polarization of the set of fuel cells to a first threshold, comparing the concentration polarization of the set of fuel cells to a second threshold, and initiating a corrective action when the ohmic polarization is above the first threshold or when the concentration polarization is below the second threshold.

An online impedance spectrum measuring device and method for a vehicle-mounted hydrogen fuel cell includes: a controllable alternating current source, configured to apply a sinusoidal alternating signal; a cell voltage signal preceding-stage measuring circuit, configured to select to communicate with one monocell via a voltage signal gating circuit; a current sensor and a cell current signal preceding-stage measuring circuit connected with the current sensor; and a signal conditioning and amplifying circuit, a multi-channel simultaneous sampling analog-digital conversion circuit, a digital signal processor and an upper computer, which are connected in sequence, wherein the signal conditioning and amplifying circuit is connected to the cell voltage signal preceding-stage measuring circuit and the cell current signal preceding-stage measuring circuit, separately; and the upper computer is connected with the controllable alternating source and the voltage signal gating circuit.