Fuel cell system and method of controlling the same

Patent metadata

Field	Value
Publication number	US-2019140291-A1
Application number	US-201816154314-A
Country	US
Kind code	A1
Filing date	Oct 8, 2018
Priority date	Nov 9, 2017
Publication date	May 9, 2019
Grant date	—

Abstract

A controller of a fuel cell system performs cathode gas supply control to raise an average cell voltage of a fuel cell stack by increasing supply of cathode gas to the fuel cell stack, when electric power required to be generated by the fuel cell stack is equal to zero, and the average cell voltage is lower than a predetermined target voltage. Under the cathode gas supply control, the controller sets the target voltage when a predetermined condition indicating that crossleak is likely to occur is satisfied, to a value higher than a reference target voltage as the target voltage in the case where the condition is not satisfied.

First claim

What is claimed is:

1 . A fuel cell system comprising:
a fuel cell stack having a plurality of unit cells; an anode gas supply unit that supplies anode gas to the fuel cell stack; a cathode gas supply unit that supplies cathode gas to the fuel cell stack; a voltage detector that detects a voltage of the fuel cell stack; and a controller that controls the anode gas supply unit and the cathode gas supply unit, wherein the controller performs cathode gas supply control to raise an average cell voltage of the fuel cell stack by increasing supply of the cathode gas to the fuel cell stack by the cathode gas supply unit, when electric power required to be generated by the fuel cell stack is equal to zero, and the average cell voltage is lower than a predetermined target voltage, and under the cathode gas supply control, the controller determines whether a predetermined condition indicating that crossleak is likely to occur is satisfied, and sets the target voltage when the predetermined condition is satisfied, to a value that is higher than a reference target voltage as the target voltage in a case where the predetermined condition is not satisfied, the crossleak representing permeation of the anode gas from an anode electrode to a cathode electrode in each of the unit cells.

2 . The fuel cell system according to claim 1 , further comprising a pressure measuring unit that measures an anode gas pressure of the fuel cell stack,
wherein the predetermined condition comprises a condition that the anode gas pressure is higher than a predetermined threshold pressure.

3 . The fuel cell system according to claim 2 , wherein, under the cathode gas supply control, the controller sets the target voltage to a higher value when the anode gas pressure is higher than the threshold pressure, than the target voltage in a case where the anode gas pressure is lower than the threshold pressure.

4 . The fuel cell system according to claim 1 , wherein the predetermined condition comprises a condition that the electric power required to be generated by the fuel cell stack immediately before the required electric power is reduced to zero is equal to or large than a predetermined threshold power.

5 . A method of controlling a fuel cell system having a fuel cell stack having a plurality of unit cells, the method comprising:
performing cathode gas supply control to raise an average cell voltage of the fuel cell stack by increasing supply of cathode gas to the fuel cell stack, when electric power required to be generated by the fuel cell stack is equal to zero, and the average cell voltage is lower than a predetermined target voltage, wherein, under the cathode gas supply control, it is determined whether a predetermined condition indicating that crossleak is likely to occur is satisfied, and the target voltage is set when the predetermined condition is satisfied, to a value that is higher than a reference target voltage as the target voltage in a case where the predetermined condition is not satisfied, the crossleak representing permeation of anode gas from an anode electrode to a cathode electrode in each of the unit cells of the fuel cell stack.

Assignees

• Toyota Motor Co Ltd

Inventors

• Namba Ryoichi
• Ishikawa Tomotaka
• Fujimura Yoshikatsu

Classifications

• H01M8/222

  Fuel cells in which the fuel is based on compounds containing nitrogen, e.g. hydrazine, ammonia · CPC title

• H01M8/04559 Primary

  of fuel cell stacks · CPC title

• H01M8/10

  Fuel cells with solid electrolytes · CPC title

• H01M8/0267

  having heating or cooling means, e.g. heaters or coolant flow channels · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title