Fuel cell system
View Patent ↗A fuel-cell stack system includes a stack of electrochemical cells, a fuel gas supply circuit and an oxidant gas supply circuit, a cooling circuit, a micropump, a temperature measurement device, and a controller. The cells are separated by bipolar plates, with each bipolar plate including an anode, a cathode, and an ion-exchange membrane. The cooling circuit, which is structured to enable a coolant fluid to circulate therein, includes a secondary circuit and a primary circuit that is smaller in size than the secondary circuit, with the primary and secondary circuits being isolated from each other by a thermostatic valve. The micropump is installed at an outlet of the stack and enables a volume of water inside the stack to be mixed. The temperature measurement device determines an internal temperature of a core of the stack. The primary circuit is activated when the internal temperature rises above a predetermined threshold.
1. A fuel-cell stack system, comprising:
a stack of electrochemical cells separated by bipolar plates, each of the bipolar plates including an anode, a cathode, and an ion-exchange membrane;
a fuel gas supply circuit and an oxidant gas supply circuit;
a cooling circuit structured to enable a coolant fluid to circulate therein, the cooling circuit including (a) a secondary circuit and (b) a primary circuit that is smaller in size than the secondary circuit, the primary and secondary circuits being isolated from each other by a thermostatic valve;
a micropump installed at an outlet of the stack, the micropump being structured to enable a volume of water inside the stack to be mixed; and
a core temperature measurement device arranged to determine an internal temperature of a core of the stack,
wherein the primary circuit is activated when the internal temperature rises above a predetermined threshold,
wherein a pump, other than the micropump, is installed in the primary circuit,
wherein when the primary circuit is activated, the pump is activated in a pulsed mode, and
wherein when the internal temperature rises above a second predetermined threshold, the pump switches from operating in the pulsed mode to operating in a continuous mode.
2. The system according to claim 1 , further comprising a cooling-circuit temperature measurement device arranged to determine a temperature in the primary circuit.
3. The system according to claim 1 , further comprising a dryer, which dries out the ion-exchange membranes when shutting down the system.
4. The system according to claim 1 , further comprising a moisture measurement device arranged to measure a moisture content of the ion-exchange membranes.
5. The system according to claim 1 , wherein in the pulsed mode, a time between two pulses is selected from within a range of 2 to 12 seconds.
6. The system according to claim 5 , wherein in the pulsed mode, an activation time of the pump is constant for each of a plurality of pulses.