Fuel cell system and control method for fuel cell system

Patent metadata

Field	Value
Publication number	US-2016351928-A1
Application number	US-201415117956-A
Country	US
Kind code	A1
Filing date	Dec 17, 2014
Priority date	Feb 17, 2014
Publication date	Dec 1, 2016
Grant date	—

Abstract

A fuel cell system is configured to generate power by supplying anode gas and cathode gas to a fuel cell. The fuel cell system includes a load connected to the fuel cell and an IV estimation unit configured to change an output current of the fuel cell with a predetermined width by adjusting power supplied to the load during the warm-up of the fuel cell. The fuel cell system is configured to estimate an IV characteristic of the fuel cell on the basis of at least two sets of an output current value and an output voltage value detected while the output current is changed. The fuel cell system includes an IV estimation stop unit configured to stop the execution of the IV estimation on the basis of an output of the fuel cell during the execution of the IV estimation.

First claim

1 .- 16 . (canceled)

17 . A fuel cell system for generating power by supplying anode gas and cathode gas to a fuel cell, comprising:
a load connected to the fuel cell; a current control unit configured to change an output current of the fuel cell with a predetermined width by adjusting power supplied to the load during the warm-up of the fuel cell; an IV estimation unit configured to estimate an IV characteristic of the fuel cell on the basis of at least two sets of an output current value and an output voltage value detected while the output current is changed; and an IV estimation stop unit configured to stop an IV estimation by the IV estimation unit when a detected value of an output voltage value of the fuel cell drops to or below a first predetermined value during the execution of the IV estimation.

18 . A fuel cell system for generating power by supplying anode gas and cathode gas to a fuel cell, comprising:
a load connected to the fuel cell; a current width control unit configured to change an output current of the fuel cell with a current width based on a state of the load and/or a state of the fuel cell system by adjusting power supplied to the load during the warm-up of the fuel cell; an IV estimation unit configured to estimate an IV characteristic of the fuel cell on the basis of at least two sets of an output current value and an output voltage value being detected while the output current is changed; and a current control stop unit configured to stop the current width control when an current width controlled by the current width control unit is smaller than a predetermined width.

19 . The fuel cell system according to claim 18 , wherein:
the current control stop unit stops the current width control when a detected value of an output voltage value of the fuel cell drops to or below a first predetermined value during the execution of an IV estimation by the IV estimation unit.

20 . The fuel cell system according to claim 17 , comprising:
a system stop unit configured to stop the fuel cell system when the detected value of the output voltage value of the fuel cell drops to or below a second predetermined value, wherein: the first predetermined value is larger than the second predetermined value.

21 . The fuel cell system according to claim 19 , wherein:
the IV estimation is executed again after the elapse of a first predetermined period when the execution of the IV estimation is stopped.

22 . The fuel cell system according to claim 21 , comprising:
an IV characteristic determination unit configured to determine whether or not the IV characteristic estimated by the IV estimation unit has reached a predetermined IV characteristic, wherein: the IV estimation is executed again after the elapse of a second predetermined period when the estimated IV characteristic is determined not to have reached the predetermined IV characteristic; and the first predetermined period is longer than the second predetermined period.

23 . The fuel cell system according to claim 21 , wherein:
the first predetermined period is set on the basis of an output current value when the detected value of the output voltage value of the fuel cell reaches the first predetermined value.

24 . The fuel cell system according to claim 23 , wherein:
the first predetermined period is set at a larger value as the output current value decreases.

25 . The fuel cell system according to claim 19 , comprising:
a limit value setting unit configured to set at least one of an upper limit value and a lower limit value of the output current on the basis of an operating state of the fuel cell system; an excess determination unit configured to determine whether or not the output current reaches the upper limit value or the lower limit value when the output current is varied; and a second IV estimation stop unit configured to stop the execution of the IV estimation when the output current is determined to reach the upper limit value or the lower limit value.

26 . The fuel cell system according to claim 19 , comprising:
an warm-up unit configured to warm up the fuel cell by adjusting the power supplied to the load such that the output current reaches a predetermined warm-up target current during the warm-up of the fuel cell, wherein: the output current of the fuel cell is varied by adjusting the power supplied to the load such that the output current is increased from the warm-up target current.

27 . The fuel cell system according to claim 19 , wherein:
the judgment whether or not the detected value of the output voltage value of the fuel cell has dropped to or below the first predetermined value is made when the output current of the fuel cell is being increased.

28 . The fuel cell system according to claim 17 , further comprising:
a minimum value setting unit configured to set a minimum value of the output current in changing the output current value of the fuel cell by the IV estimation unit to ensure IV estimation accuracy by the IV estimation unit, wherein: the execution of the IV estimation is stopped when the output current of the fuel cell is judged to drop below the minimum value during the execution of the IV estimation.

29 . The fuel cell system according to claim 28 , wherein:
the IV estimation is executed again after a battery as the load is discharged when the execution of the IV estimation is stopped.

30 . The fuel cell system according to claim 28 , wherein:
the minimum value setting unit decreases the minimum value as the warm-up of the fuel cell progresses.

31 . The fuel cell system according to claim 28 , comprising:
an warm-up unit configured to warm up the fuel cell by adjusting the power supplied to the load such that the output current reaches a predetermined warm-up target current during the warm-up of the fuel cell, wherein: the power supplied to the load is adjusted such that the output current is reduced after the output current is increased from the warm-up target current and the IV estimation unit estimates the IV characteristic of the fuel cell on the basis of at least two sets of the output current value and the output voltage value detected while the output current is reduced.

32 . A control method for a fuel cell system configured to supply anode gas and cathode gas to the fuel cell so as to generate power according to a load connected to a fuel cell, comprising:
an current control step of changing an output current of the fuel cell with a predetermined width during the warm-up of the fuel cell by adjusting power supplied to the load; an IV estimation step of estimating an IV characteristic of the fuel cell on the basis of at least two sets of an output current value and an output voltage value detected while the output current is changed; and an IV estimation stop step of stopping the execution of the IV estimation step when a detected value of an output voltage value of the fuel cell drops to or below a first predetermined value during the execution of the IV estimation step.

Assignees

• Nissan Motor

Inventors

• Hoshi Kiyoshi

Classifications

• H01M8/04955

  Shut-off or shut-down of fuel cells · CPC title

• B60L58/34

  by heating · CPC title

• H01M8/04649

  of fuel cell stacks · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/04582

  of the individual fuel cell · CPC title