Fuel cell system and control method for fuel cell system

Patent metadata

Field	Value
Publication number	US-2018375129-A1
Application number	US-201616063888-A
Country	US
Kind code	A1
Filing date	Nov 14, 2016
Priority date	Dec 25, 2015
Publication date	Dec 27, 2018
Grant date	—

Abstract

A fuel cell system comprising: a fuel cell;
a combustor configured to combust a fuel and an oxidizing gas to supply a combustion gas to a cathode inlet of the fuel cell; a combustion fuel supply device configured to supply a fuel to the combustor; a combustion oxidizing gas supply device configured to supply an oxidizing gas to the combustor; an anode-discharged-gas discharge passage configured to discharge an anode discharged gas from an anode outlet of the fuel cell; a cathode-discharged-gas discharge passage configured to discharge a cathode discharged gas from a cathode outlet of the fuel cell; and a controller configured to control a supply of the fuel to the combustor by the combustion fuel supply device and a supply of the oxidizing gas to the combustor by the combustion oxidizing gas supply device, wherein the controller includes a post-stop-request combustor-supply control unit configured to execute the supply of the fuel and the supply of the oxidizing gas to the combustor after a request for stopping the fuel cell system.

First claim

1 .- 18 . (canceled)

19 . A fuel cell system comprising:
a fuel cell; a combustor configured to combust a fuel and an oxidizing gas to supply a combustion gas to a cathode inlet of the fuel cell; a combustion fuel supply device configured to supply a fuel to the combustor; a combustion oxidizing gas supply device configured to supply an oxidizing gas to the combustor; an anode-discharged-gas discharge passage configured to discharge an anode discharged gas from an anode outlet of the fuel cell; a cathode-discharged-gas discharge passage configured to discharge a cathode discharged gas from a cathode outlet of the fuel cell; and a controller configured to control a supply of the fuel to the combustor by the combustion fuel supply device and a supply of the oxidizing gas to the combustor by the combustion oxidizing gas supply device, wherein the controller includes:
a post-stop-request combustor-supply control unit configured to execute the supply of the fuel and the supply of the oxidizing gas to the combustor as an anode degradation reduction process after a request for stopping the fuel cell system, and
an anode degradation reduction processing unit configured to perform another anode degradation reduction process in a case where the oxygen partial pressure of an anode pole of the fuel cell becomes equal to or more than a predetermined upper limit threshold value after the request for stopping the fuel cell and during supply of a fuel and an oxidizing gas.

20 . The fuel cell system according to claim 19 , wherein:
the combustor is an activation combustor configured to be supplied with a fuel and an oxidizing gas during a warm-up operation executed at activation of the fuel cell, and combust the fuel and the oxidizing gas to supply a combustion gas to the cathode inlet of the fuel cell, and the controller stops a supply of an air to the activation combustor after a termination of the warm-up operation.

21 . The fuel cell system according to claim 19 , wherein
the post-stop-request combustor-supply control unit adjusts at least any one of a supply amount of a fuel and a supply amount of an oxidizing gas such that an excess ratio of an oxidizing gas to a fuel has a predetermined value for suppressing an oxidative degradation of an anode pole of the fuel cell.

22 . The fuel cell system according to claim 21 , wherein
the predetermined value is one.

23 . The fuel cell system according to claim 20 , wherein
the controller further includes an anode oxygen partial pressure operation unit configured to operate an oxygen partial pressure of the anode pole of the fuel cell, and the post-stop-request combustor-supply control unit adjusts a supply amount of a fuel on the basis of the oxygen partial pressure of the anode pole.

24 . The fuel cell system according to claim 23 , wherein
the post-stop-request combustor-supply control unit adjusts a supply amount of a fuel such that the oxygen partial pressure of the anode pole becomes less than a predetermined upper limit threshold value.

25 . The fuel cell system according to claim 24 , wherein
the upper limit threshold value is determined corresponding to a temperature of the fuel cell.

26 . The fuel cell system according to claim 23 , wherein
the anode oxygen partial pressure operation unit operates the oxygen partial pressure of the anode pole on the basis of the temperature of the fuel cell, an oxygen partial pressure of a cathode pole of the fuel cell, and an inter-terminal voltage of the fuel cell.

27 . The fuel cell system according to claim 19 , wherein
the anode degradation reduction process includes a reverse voltage application process configured to apply an electromotive force reverse to the fuel cell to the fuel cell.

28 . The fuel cell system according to claim 19 , wherein
the anode degradation reduction process includes a fuel cell fuel supply process configured to supply a fuel to the fuel cell.

29 . The fuel cell system according to claim 19 , wherein
the post-stop-request combustor-supply control unit adjusts a supply amount of a fuel such that a heat generation amount of combustion by the combustor becomes equal to or less than a heat dissipation of the fuel cell.

30 . The fuel cell system according to claim 29 , wherein
the post-stop-request combustor-supply control unit controls a supply flow rate of an oxidizing gas to the fuel cell to a lowest flow rate.

31 . The fuel cell system according to claim 29 , further comprising:
a fuel cell temperature obtaining unit configured to obtain a temperature of the fuel cell; and an outside air temperature obtaining unit configured to obtain an outside air temperature, wherein the post-stop-request combustor-supply control unit further includes a fuel cell heat dissipation calculator configured to calculate the heat dissipation of the fuel cell on the basis of the temperature of the fuel cell and the outside air temperature.

32 . The fuel cell system according to claim 19 , wherein
the combustor is arranged on an oxidizing gas supply passage configured to supply an oxidizing gas to the cathode inlet of the fuel cell.

33 . A control method for a fuel cell system comprising:
supplying a fuel and an oxidizing gas to a combustor in the fuel cell system as an anode degradation reduction process after a request for stopping a fuel cell in the fuel cell system to supply a combustion gas generated by the combustor to a cathode inlet of the fuel cell, and performing another anode degradation reduction process when an oxygen partial pressure of an anode pole of the fuel cell becomes equal to or more than a predetermined upper limit threshold value after the request for stopping the fuel cell and during the supply of the fuel and the oxidizing gas to the combustor.

34 . The control method for the fuel cell system according to claim 33 , wherein
at least any one of a supply amount of a fuel and a supply amount of an oxidizing gas is adjusted such that an excess ratio of an oxidizing gas to a fuel has a predetermined value for suppressing an oxidative degradation of an anode pole of the fuel cell.

35 . The control method for the fuel cell system according to claim 34 , wherein
the predetermined value is one.

Assignees

• Nissan Motor

Inventors

• Yaguchi Tatsuya

Classifications

• H01M8/04303 Primary

  applied during shut-down · CPC title

• H01M8/04302

  applied during start-up · CPC title

• H01M8/04388

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

• H01M8/04753

  of fuel cell reactants · CPC title

• H01M8/12

  operating at high temperature, e.g. with stabilised ZrO2 electrolyte · CPC title