Warming-up control method in starting process of fuel cell system and fuel cell system

A warming-up control method for a fuel cell system in a starting process, comprising:

• (a) starting the fuel cell system, introducing hydrogen and air into a stack, turning on a small-cycle cooling circuit, and pull-loading an output power of the fuel cell system to a first power;
• (b) running the fuel cell system at the first power, and monitoring an inlet temperature of the stack in real time;
• (c) in response to the inlet temperature reaching a first temperature, proceeding to step (d);
• (d) rotating a three-way valve at a first rotating rate, so as to simultaneously gradually turn on a large-cycle cooling circuit and gradually turn off the small-cycle cooling circuit;
• (e) monitoring a cell voltage value of the stack in real time, and calculating a voltage variance based on the cell voltage value;
• (f) in response to the voltage variance being smaller than or equal to a first threshold, returning to step (d) until all turn-on of the large-cycle cooling circuit and all turn-off of the small-cycle cooling circuit;
• (g) subsequent to all turn-on of the large-cycle cooling circuit and all turn-off of the small-cycle cooling circuit, pull-loading the output power of the fuel cell system to a rated power;
• (h) in response to the voltage variance being larger than the first threshold and smaller than or equal to a second threshold, rotating the three-way valve at a second rotating rate until the voltage variance is smaller than or equal to the first threshold, and returning to step (d), wherein the second rotating rate is smaller than the first rotating rate;
• (i) in response to the voltage variance being larger than the second threshold and smaller than or equal to a third threshold, decreasing the output power of the fuel cell system from the first power to a second power;
• (j) running the fuel cell system at the second power, and monitoring the inlet temperature of the stack in real time;
• (k) in response to the inlet temperature reaching a second temperature, rotating the three-way valve at a third rotating rate until the voltage variance is smaller than or equal to the first threshold, and returning to the step of rotating a three-way valve at a first rotating rate, wherein the third rotating rate is smaller than the second rotating rate, and the second temperature is smaller than the first temperature;
• and
• (l) in response to the voltage variance being larger than the third threshold, determining that the fuel cell system fails and stopping starting of the fuel cell system.