Fuel cell system and control method for fuel cell system

A control method for a fuel cell system for supplying anode gas and cathode gas to a fuel cell and causing the fuel cell to generate power according to a load, the fuel cell system including a component configured to circulate discharged gas including anode gas or cathode gas discharged from the fuel cell to an inlet of the fuel cell, the control method comprising:

• controlling a power generation state of the fuel cell based on the load;
• predicting freezing of the component by detecting a temperature of the fuel cell system;
• executing, while the fuel cell generates power, when the freezing of the component is predicted and a stop command to stop the power generation of the fuel cell has been received, a warm-up operation before stopping the fuel cell in response to the stop command,
• wherein the controlling a power generation state includes calculating a flow rate of the cathode gas as a power generation request flow rate on the basis of the load;
• comparing a warm-up request flow rate of the cathode gas and the power generation request flow rate;
• setting the warm-up request flow rate as the flow rate of the cathode gas during the warm-up operation when the warm-up request flow rate is greater than the power generation request flow rate;
• and
• setting the power generation request flow rate as the flow rate of the cathode gas during the warm-up operation when the power generation request flow rate is greater than the warm-up request flow rate.

A fuel cell system for supplying anode gas and cathode gas to a fuel cell and causing the fuel cell to generate power according to a load, comprising:

• a jet pump configured to circulate discharged gas comprising anode gas or cathode gas discharged from the fuel cell to an inlet of the fuel cell;
• and
• a controller programmed to:
• control a power generation state of the fuel cell based on the load;
• predict freezing of the jet pump with a temperature sensor configured to detect a temperature of the fuel cell system;
• while the fuel cell generates power, when the freezing of the jet pump is predicted and a stop command to stop the power generation of the fuel cell has been received, execute a warm-up operation before stopping the fuel cell in response to the stop command, wherein the controlling a power generation state includes calculating a flow rate of the cathode gas as a power generation request flow rate on the basis of the load;
• compare a warm-up request flow rate of the cathode gas and the power generation request flow rate;
• set the warm-up request flow rate as the flow rate of the cathode gas during the warm-up operation when the warm-up request flow rate is greater than the power generation request flow rate;
• and
• set the power generation request flow rate as the flow rate of the cathode gas during the warm-up operation when the power generation request flow rate is greater than the warm-up request flow rate.