Fuel cell system and control method for fuel cell system

Patent metadata

Field	Value
Publication number	US-2018358639-A1
Application number	US-201615781248-A
Country	US
Kind code	A1
Filing date	Sep 26, 2016
Priority date	Dec 15, 2015
Publication date	Dec 13, 2018
Grant date	—

Abstract

A fuel cell system includes a solid oxide fuel cell configured to receive a supply of an anode gas and a cathode gas to generate electric power. The fuel cell system includes an anode discharge passage through which an anode off-gas discharged from the fuel cell flows, a cathode discharge passage through which a cathode off-gas discharged from the fuel cell flows, a joining portion where the anode discharge passage and the cathode discharge passage join. The fuel cell system further includes a gas supply unit configured to supply a fuel gas using a fuel stored in a fuel tank into the anode discharge passage during a system stop.

First claim

1 .- 14 . (cancelled)

15 . A fuel cell system including a solid oxide fuel cell configured to receive a supply of an anode gas and a cathode gas to generate electric power, the fuel cell system comprising:
an anode discharge passage through which an anode off-gas discharged from the fuel cell flows; a cathode discharge passage through which a cathode off-gas discharged from the fuel cell flows; a joining portion where the anode discharge passage and the cathode discharge passage join; a gas supply unit configured to supply a fuel gas using a fuel stored in a fuel tank into the anode discharge passage during a system stop; and a temperature-sensing unit configured to detect or estimate a temperature of the fuel cell, wherein the gas supply unit is configured to supply a fuel gas to the anode discharge passage on the basis of the temperature of the fuel cell.

16 . The fuel cell system according to claim 15 , wherein
the gas supply unit is configured such that a fuel gas is supplied to the anode discharge passage when the temperature of the fuel cell is higher than a reference temperature at which an anode electrode of the fuel cell is not oxidized during the system stop.

17 . The fuel cell system according to claim 16 , wherein
the gas supply unit is configured to increase a fuel gas supply amount as the temperature of the fuel cell decreases.

18 . The fuel cell system according to claim 16 , further comprising
an oxygen concentration detecting unit configured to detect or estimate an oxygen concentration in the anode discharge passage, wherein the gas supply unit is configured to adjust a fuel gas supply amount corresponding to the oxygen concentration.

19 . The fuel cell system according to claim 18 , wherein
the gas supply unit is configured to increase a fuel gas supply amount as a deviation between the oxygen concentration and the reference concentration with which the anode electrode of the fuel cell is not oxidized increases.

20 . The fuel cell system according to claim 19 , wherein
the reference concentration is set small as the temperature of the fuel cell decreases.

21 . The fuel cell system according to claim 15 , wherein
the joining portion is a discharged gas combustor that combusts an anode off-gas and a cathode off-gas.

22 . The fuel cell system according to claim 16 , wherein
the gas supply unit comprises an injector disposed in the anode discharge passage, the injector being configured as a supply unit different from an anode gas supply unit configured to supply an anode gas to the fuel cell, and the injector includes a heating apparatus that evaporates a fuel supplied from the fuel tank, the injector being configured to supply the evaporated fuel to the anode discharge passage as a fuel gas.

23 . The fuel cell system according to claim 22 , further comprising:
a reformer that constitutes the anode gas supply unit, the reformer reforming a fuel supplied from the fuel tank to an anode gas, the reformer supplying the anode gas to the fuel cell; and a reformer temperature-sensing unit configured to detect or estimate a temperature of the reformer, wherein when the temperature of the fuel cell is higher than the reference temperature and the temperature of the reformer is higher than a reformer reference temperature, an anode gas reformed by the reformer is supplied to the anode discharge passage as a fuel gas, and when the temperature of the fuel cell is higher than the reference temperature and the temperature of the reformer is equal to or less than the reformer reference temperature, an evaporated fuel from the injector is supplied to the anode discharge passage.

24 . A control method for a fuel cell system including a solid oxide fuel cell configured to receive a supply of an anode gas and a cathode gas to generate electric power, an anode discharge passage and a cathode discharge passage through which an anode off-gas and a cathode off-gas discharged from the fuel cell respectively flow, and a joining portion where the anode discharge passage and the cathode discharge passage join, the control method comprising:
detecting or estimating a temperature of the fuel cell; and supplying a fuel gas using a fuel stored in a fuel tank into the anode discharge passage on the basis of the temperature of the fuel cell during a system stop.

25 . The control method for the fuel cell system according to claim 24 , comprising
supplying the fuel gas to the anode discharge passage when the temperature of the fuel cell is higher than a reference temperature at which an anode electrode of the fuel cell is not oxidized during the system stop.

26 . The control method for the fuel cell system according to claim 25 , comprising
increasing the fuel gas supply amount as the temperature of the fuel cell decreases.

27 . The control method for the fuel cell system according to claim 25 , comprising:
detecting or estimating an oxygen concentration in the anode discharge passage, and adjusting a supply amount of the fuel gas corresponding to the oxygen concentration.

28 . The control method for the fuel cell system according to claim 27 , comprising
increasing the fuel gas supply amount as a deviation between the oxygen concentration and the reference concentration with which the anode electrode of the fuel cell is not oxidized increases.

Assignees

• Nissan Motor
• Nissan Motor Co Ltd Ip Dept

Inventors

• Yajima Kentarou
• Yanagisawa Masanari
• Maeshima Susumu

Classifications

• B60L50/75

  using propulsion power supplied by both fuel cells and batteries · CPC title

• C01B2203/1619

  Measuring the temperature · CPC title

• H01M8/04228

  during shut-down · CPC title

• C01B2203/1229

  Ethanol · CPC title

• C01B2203/0233

  the reforming step being a steam reforming step · CPC title