Fuel cell system and method for controlling fuel cell system

Patent metadata

Field	Value
Publication number	US-2020212458-A1
Application number	US-201716632609-A
Country	US
Kind code	A1
Filing date	Aug 1, 2017
Priority date	Aug 1, 2017
Publication date	Jul 2, 2020
Grant date	—

Abstract

A fuel cell system includes: a fuel cell; a fuel treating unit configured to treat a raw fuel and generate fuel gas for the fuel cell; an oxidant-gas heater configured to heat oxidant gas for the fuel cell; a combustor configured to combust the raw fuel and generate combustion gas to heat the fuel treating unit and the oxidant-gas heater; and a control unit configured to control supplying of the raw fuel to the fuel treating unit and the combustor at the time of warming-up of the fuel cell. The control unit supplies the raw fuel to both of the fuel treating unit and the combustor when the fuel treating unit is at an operable temperature of the fuel treating unit.

First claim

1 .- 13 . (canceled)

14 . A fuel cell system comprising:
a fuel cell; a fuel treating unit configured to treat raw fuel and generate fuel gas for the fuel cell; an oxidant-gas heater configured to heat oxidant gas for the fuel cell; a combustor configured to combust the raw fuel and generate combustion gas to heat the fuel treating unit and the oxidant-gas heater; and a control unit configured to control supplying of the raw fuel to the fuel treating unit and the combustor at the time of warming-up of the fuel cell, when the fuel treating unit is at an operable temperature of the fuel treating unit, the control unit dividing the raw fuel between the fuel treating unit and the combustor for supplying so that the flow rate of the raw fuel is larger than a supplying flow rate of the raw fuel at a rated operation following warming up.

15 . A fuel cell system comprising:
a fuel cell; a fuel treating unit disposed on an anode-gas flow path of the fuel cell, and configured to treat raw fuel; an oxidant-gas heater disposed on a cathode-gas flow path of the fuel cell, and configured to heat oxidant gas; a combustor configured to combust the raw fuel and heat the fuel treating unit and the oxidant-gas heater with combustion gas of the raw fuel; and a control unit configured to control supplying of the raw fuel to the fuel treating unit and the combustor; the control unit including: a temperature detection unit configured to detect a temperature of the fuel cell; a warming-up target flow rate setting unit configured to set a warming-up target flow rate in accordance with a temperature of the fuel cell, the warming-up target flow rate being a target flow rate of the raw fuel at the time of warming up of the fuel cell, and after starting of warming-up, to increase the warming-up target flow rate in accordance with a temperature rise of the fuel cell; and a fuel supplying control unit configured to, when the fuel treating unit reaches an operable temperature of the fuel treating unit, continuously increase the warming-up target flow rate, and supply the raw fuel of the warming-up target flow rate to both of the fuel treating unit and the combustor.

16 . The fuel cell system according to claim 15 , wherein
after the fuel treating unit reaches the operable temperature, the fuel supplying control unit increases the flow rate of the raw fuel to be supplied to the combustor in accordance with a temperature rise of the fuel cell.

17 . The fuel cell system according to claim 15 , wherein
the temperature detection unit detects a temperature of an exit of the fuel cell as the temperature of the fuel cell.

18 . The fuel cell system according to claim 17 , wherein
the control unit further including: an oxidant-gas flow rate detection unit configured to detect an oxidant-gas flow rate that is a flow rate of the oxidant gas supplied to the fuel cell; and a target combustion-gas temperature setting unit configured to set a target combustion-gas temperature that is a target temperature of the combustion gas based on the temperature of the exit of the fuel cell, wherein the warming-up target flow rate setting unit sets the warming-up target flow rate based on the target combustion-gas temperature, the oxidant-gas flow rate, and the temperature of the exit of the fuel cell.

19 . The fuel cell system according to claim 15 , wherein
the warming-up target flow rate is larger than a flow rate of the raw fuel at a rated operation following warming up.

20 . The fuel cell system according to claim 19 , wherein
the fuel supplying control unit supplies the raw fuel of a flow rate required for the rated operation to the fuel treating unit, and supplies the raw fuel corresponding to shortage of the flow rate required for the rate operation relative to the warming-up target flow rate to the combustor.

21 . The fuel cell system according to claim 15 , wherein
the combustor connects to an anode off-gas flow path and a cathode off-gas flow path of the fuel cell.

22 . The fuel cell system according to claim 14 , wherein
when the temperature of the fuel treating unit is less than the operable temperature, the control unit supplies the raw fuel only to the combustor between the fuel treating unit and the combustor.

23 . The fuel cell system according to claim 14 , wherein
the fuel treating unit includes a reformer configured to reform the raw fuel into the fuel gas, and when the temperature of the reformer is at a temperature enabling reforming of the raw fuel, the control unit supplies the raw fuel to both of the fuel treating unit and the combustor.

24 . The fuel cell system according to claim 23 , wherein
the control unit detects, as a temperature of the reformer, a temperature of the fuel gas downstream of the reformer.

25 . The fuel cell system according to claim 14 , wherein
the fuel treating unit includes an evaporator configured to evaporate the raw fuel in the form of liquid, and when the temperature of the evaporator is at a temperature enabling evaporation of the raw fuel, the control unit supplies the raw fuel to both of the fuel treating unit and the combustor.

26 . The fuel cell system according to claim 25 , wherein
the control unit detects, as a temperature of the evaporator, a temperature of the combustion gas downstream of the evaporator.

27 . A control method for fuel cell system, the method controlling a fuel cell system configured to supply fuel gas generated from a treatment of a raw fuel to a fuel cell, comprising:
at the time of startup of the fuel cell system, determining whether the fuel cell system is ready for treatment of the raw fuel or not; when the fuel cell system is ready for treatment of the raw fuel, treating the raw fuel; supplying the fuel gas to the fuel cell; combusting the raw fuel; promoting the treatment of the raw fuel while heating oxidant gas to be supplied to the fuel cell with combustion gas of the raw fuel generated by the combustion as a heat source; and dividing the raw fuel between the treatment and the combustion of the raw fuel so that the flow rate of the raw fuel is larger than a flow rate of the raw fuel required for a rated operation of the fuel cell.

Assignees

• Nissan Motor

Inventors

• Noda Tetsushi
• Chikugo Hayato
• Yaguchi Tatsuya

Classifications

• Y02E60/50

  Fuel cells · CPC title

• H01M8/0432

  Temperature; Ambient temperature · CPC title

• H01M8/04753

  of fuel cell reactants · CPC title

• H01M8/0618 Primary

  Reforming processes, e.g. autothermal, partial oxidation or steam reforming · CPC title

• H01M8/04022 Primary

  Heating by combustion · CPC title