Fuel cell system and control method at time of starting-up fuel cell system

A fuel cell system, comprising:

• a first fuel cell set including a first fuel cell stack and a first air supply unit configured to supply air to the first fuel cell stack;
• a second fuel cell set including a second fuel cell stack and a second air supply unit configured to supply air to the second fuel stack;
• an electricity storage unit configured to supply electric power to the first air supply unit and the second air supply unit which are electrically connected in parallel;
• a connection unit through which output voltages of the first fuel cell stack and the second fuel cell stack are able to be applied to the first air supply unit and the second air supply unit;
• a control unit configured to control the first fuel cell set and the second fuel cell set;
• a third fuel cell set including a third fuel cell stack connected to the first fuel cell stack in series and a third air supply unit configured to supply air to the third fuel cell stack;
• and
• a fourth fuel cell set including a fourth fuel cell stack connected to the second fuel cell stack in series and a fourth air supply unit configured to supply air to the fourth fuel cell stack,
• wherein the first fuel cell stack and the second fuel cell stack are connected to an electric load,
• at the time of starting up the first fuel cell set and the second fuel cell set, the control unit drives one of the first air supply unit and the second air supply unit and then drives another air supply unit so that electric power of the another air supply unit reaches a peak after an output voltage of the one of the fuel cell stacks reaches the first output value, and
• wherein the third air supply unit and the fourth air supply unit are electrically connected to the first air supply unit and the second air supply unit in parallel.

A control method at the time of starting-up a fuel cell system which includes:

• a first fuel cell set including a first fuel cell stack and a first air supply unit configured to supply air to the first fuel cell stack;
• a second fuel cell set including a second fuel cell stack and a second air supply unit configured to supply air to the second fuel cell stack;
• an electric load connected to the first fuel cell stack and the second fuel cell stack which are electrically connected in parallel;
• an electricity storage unit configured to supply electric power to the first air supply unit and the second air supply unit which are electrically connected in parallel;
• a connection unit through which output voltages of the first fuel cell stack and the second fuel cell stack are able to be applied to the first air supply unit and the second air supply unit;
• and
• a control unit configured to control the first fuel cell set and the second fuel cell set, the method comprising:
• at the time of starting up the first fuel cell set and the second fuel cell set when the first fuel cell stack and the second fuel cell stack are filled and sealed with hydrogen, driving one of the first air supply unit to discharge the hydrogen filled in the first fuel cell stack to reach a maximum power consumption at the time of starting up and then driving the second air supply unit so that the second air supply unit reaches its maximum power consumption at the time of starting up for discharging the hydrogen filled in the second fuel cell stack after an output voltage of the first fuel cell stacks reaches a second stage start-up threshold voltage.

A control method at the time of starting-up a fuel cell system which includes:

• a first fuel cell stack and a first air supply unit configured to supply air to the first fuel cell stack;
• a second fuel cell set including a second fuel cell stack and a second air supply unit configured to supply air to the second fuel cell stack;
• an electric load connected to the first fuel cell stack and the second fuel cell stack which are electrically connected in parallel;
• a connection unit through which output voltages of the first fuel cell stack and the second fuel cell stack are able to be applied to the first air supply unit and the second air supply unit;
• a control unit configured to control the first fuel cell set and the second fuel cell set;
• and
• a third fuel cell set including a third fuel cell stack connected to the first fuel cell stack in series and a third air supply unit configured to supply air to the third fuel cell stack and a fourth fuel cell set including a fourth fuel cell stack connected to the second fuel cell stack in series and a fourth air supply unit configured to supply air to the fourth fuel cell stack, the method comprising:
• at the time of starting up the first fuel cell set and the second fuel cell set, driving one of the first air supply unit and the second air supply unit and then driving another air supply unit so that electric power of the another air supply unit reaches a peak after an output voltage of the one of the fuel cell stacks reaches the first output value, and
• the third air supply unit and the fourth air supply unit are electrically connected to the first air supply unit and the second air supply unit in parallel.