Fuel cell system and method for controlling fuel cell system

Patent metadata

Field	Value
Publication number	US-2016285117-A1
Application number	US-201414778414-A
Country	US
Kind code	A1
Filing date	Feb 14, 2014
Priority date	Mar 22, 2013
Publication date	Sep 29, 2016
Grant date	—

Abstract

A fuel cell system supplies anode and cathode gases, and generates power through an electrochemical reaction of the gases in accordance with a load. The system includes a compressor that supplies the cathode gas to a fuel cell stack, and a pressure regulator valve that adjusts the pressure of the cathode gas in the fuel cell stack. The system sets a target cathode pressure based on a power generation request to the fuel cell stack, and controls an operation amount of the compressor and an opening degree of a pressure regulator valve based on the target cathode pressure. The temperature of air discharged by the compressor is restricted to an upper temperature limit by restricting the operation amount of the compressor and/or the opening degree of the pressure regulator valve based on two parameters, i.e., the inlet temperature and the torque of the compressor.

First claim

1 .- 8 . (canceled)

9 . A fuel cell system for supplying an anode gas and a cathode gas, and generating power through an electrochemical reaction of the anode gas and the cathode gas in accordance with a load, the fuel cell system comprising:
a compressor for supplying the cathode gas to a fuel cell stack; a pressure regulator valve for adjusting a pressure of the cathode gas in the fuel cell stack; a target cathode pressure setting unit for setting a target cathode pressure based on a power generation request to the fuel cell stack; a control unit for controlling an operation amount of the compressor and an opening degree of the pressure regulator valve based on the target cathode pressure; a unit for detecting an actual rotation frequency of the compressor; and a restricting unit for restricting the operation amount of the compressor and/or the opening degree of the pressure regulator valve based on two parameters, the two parameters being an inlet temperature of the compressor and a torque of the compressor, wherein the restricting unit sets a rotation frequency limit of the compressor based on the two parameters, calculates a pressure limit based on the rotation frequency limit and the actual rotation frequency, and restricts the operation amount of the compressor and/or the opening degree of the pressure regulator valve based on the pressure limit.

10 . The fuel cell system according to claim 9 , further comprising:
a first target flow rate setting unit for setting a first target flow rate based on the power generation request to the fuel cell stack; a second target flow rate computation unit for computing a second target flow rate of the cathode gas based on the pressure limit; and a cathode flow rate control unit for controlling a cathode flow rate through the operation amount of the compressor and/or the opening degree of the pressure regulator valve based on a lower one of the first target flow rate and the second target flow rate.

11 . The fuel cell system according to claim 10 , wherein
the second target flow rate has a smaller value than the first target flow rate calculated based on the power generation request to the fuel cell stack when the pressure regulator valve is fully open.

12 . The fuel cell system according to claim 9 , wherein
the restricting unit corrects the torque of the compressor so that the rotation frequency limit of the compressor decreases as an atmospheric pressure increases.

13 . The fuel cell system according to claim 9 , further comprising:
a detecting unit for detecting an actual cathode pressure in the fuel cell stack; and a cathode gas flow rate detecting unit for detecting a cathode gas flow rate, wherein a fuel cell output is restricted based on the cathode gas flow rate and the actual cathode pressure.

14 . A control method for a fuel cell system including a compressor for supplying a cathode gas to a fuel cell stack and a pressure regulator valve for adjusting a pressure of the cathode gas in the fuel cell stack, the fuel cell system supplying an anode gas and the cathode gas and generating power through an electrochemical reaction of the anode gas and the cathode gas in accordance with a load, the control method comprising:
setting a target cathode pressure based on a power generation request to the fuel cell stack; controlling an operation amount of the compressor and an opening degree of the pressure regulator valve based on the target cathode pressure; detecting an actual rotation frequency of the compressor; and restricting the operation amount of the compressor and/or the opening degree of the pressure regulator valve based on two parameters, the two parameters being an inlet temperature of the compressor and a torque of the compressor, wherein at the time of the restriction, a rotation frequency limit of the compressor is set based on the two parameters, a pressure limit is calculated based on the rotation frequency limit and the actual rotation frequency, and the restriction of the operation amount of the compressor and/or the opening degree of the pressure regulator valve is performed based on the pressure limit.

Assignees

• Nissan Motor

Inventors

• Tomita Yosuke
• Chikugo Hayato

Classifications

• H01M8/04104

  Regulation of differential pressures · CPC title

• H01M8/04776

  at auxiliary devices, e.g. reformer, compressor, burner · CPC title

• H01M8/04395

  of cathode reactants at the inlet or inside the fuel cell · CPC title

• H01M8/04201

  Reactant storage and supply, e.g. means for feeding, pipes · CPC title

• H01M8/04373

  of auxiliary devices, e.g. reformers, compressors, burners · CPC title