Methods and systems are provided for iron preformation in a redox flow battery. In one example, a method may include, in a first condition, discharging and then charging the redox flow battery, and in a second condition, charging the redox flow battery including preforming iron metal at a negative electrode of the redox flow battery, and thereafter entering an idle mode of the redox flow battery including adjusting one or more electrolyte conditions. In some examples, each of preforming the iron metal and adjusting the one or more electrolyte conditions may increase a battery charge capacity to greater than a threshold battery charge capacity.

A fuel cell control command device including: a catalyst potential calculation unit for calculating a catalyst potential of a cathode catalyst; a coating state calculation unit for calculating an oxide film formation amount of the catalyst; a command value candidate calculation unit for calculating a plurality of command value candidates including a combination of an estimated current, estimated total voltage, and a candidate control parameter, from which a power command value is obtained; a loss amount calculation unit for calculating an estimated loss for each combination; a provisional catalyst potential calculation unit for calculating an estimated catalyst potential for each combination; a deterioration amount calculation unit for calculating an estimated deterioration amount for each combination; and a command value calculation unit for selecting a combination having a minimum comprehensive index including the estimated loss and/or the estimated deterioration amount and outputting the selected combination as a command value.

In a case where each of the temperature, the impedance, and the output current of a fuel cell stack falls within a predetermined range, the output voltage of the fuel cell stack is measured, and the measured output voltage is compared with a reference value to thereby determine the degree of degradation of the fuel cell stack.

A temperature control apparatus and method for fuel cell system, where the apparatus includes a fuel cell stack, a first pump disposed on a first cooling line, a first radiator disposed on the first cooling line, power electronic parts, a second pump disposed on a second cooling line, a second radiator disposed on the second cooling line, a cooling fan configured to blow exterior air to any one of the first radiator and the second radiator, and a controller configured to determine an RPM of the cooling fan based on a coolant temperature at an inlet of the fuel cell stack and a first exterior air temperature, to determine a target cooling performance of the plurality of power electronic parts based on power consumptions of the plurality of power electronic parts, and to determine an RPM of the second pump based on the target cooling performance of the plurality of power electronic parts, the RPM of the cooling fan, and a second exterior air temperature.

A fuel cell system includes a fuel cell stack, a circulation circuit, a gas liquid separator section, a purge channel, a purge valve and an ECU. In a method of operating the fuel cell system at low temperature, after start-up of the fuel cell system, the ECU performs a freezing determination processing step of determining freezing or non-freezing of the gas liquid separator, and in the case where freezing of the gas liquid separator is determined in the freezing determination step, the ECU performs a freezing confirmation processing step of immediately opening the purge valve for predetermined time.

A fuel cell power plant cooling system may include a power unit coolant supply line configured to receive a coolant, two or more fuel cell system coolant supply lines connected to the power unit coolant supply line and configured to receive coolant from the power unit coolant supply line, two or more fuel cell systems configured to be cooled by the two or more fuel cell system coolant supply lines, respectively, two or more fuel cell system return supply lines connected to the two or more fuel cell system coolant supply lines, respectively, and configured to receive coolant from the two or more fuel cell system coolant supply lines, and a power unit return supply line connected to the two or more fuel cell system return supply lines and configured to receive coolant from the two or more fuel cell system return supply lines, respectively.

A fuel cell power plant system may include two or more electrically connected power units, two or more voltage channels, and a fuel cell power plant controller. Each one of the two or more power units may include two or more fuel cell systems. The two or more voltage channels may be respectively connected to the two or more power units. The fuel cell power plant controller may be electrically connected to the two or more power units.

A fuel cell power plant system may include two or more power units and a fuel cell power plant controller. The two or more power units may be electrically connected. Each one of the two or more power units may include two or more fuel cell systems. The fuel cell power plant controller may be electrically connected to the two or more power units and may include a user control circuitry and a monitoring circuitry. The user control circuitry may control a mode of operation of the fuel cell power plant system to be run in an operation mode, a standby mode, a maintenance mode, or an emergency stopped mode. The monitoring circuitry may monitor the two or more power units of the fuel cell power plant system for one or more fault conditions, one or more alarms, or an amount of energy produced.

A heat exchanger for a fuel cell power plant system may include a first loop and a second loop. For the first loop, a first coolant may be passed through a fuel cell stack, a thermostat, a first portion of a first plate of the heat exchanger, and a fuel cell pump. For the second loop, a second coolant may be passed through a second portion of the first plate of the heat exchanger.

Disclosed are an apparatus and a method for individually controlling fuel cell modules of a multi-module cell system. According to the present disclosure, a driving number calculator calculates a first number, based on a required total output and a preset fuel cell stack reference output in real time, a fuel cell stack driving determiner determines driven ones of the one or more fuel cell stacks, based on priorities of the one or more fuel cells and the first number, and a fuel cell stack output controller controls an output of the driven fuel cell stack based on the required total output. Through the present disclosure, durability degrees of the fuel cell stacks may be secured by controlling voltage for cells of the fuel cell stacks in a proper range.