Fuel cell system and method for controlling fuel cell system

Patent metadata

Field	Value
Publication number	US-9843056-B2
Application number	US-201415027402-A
Country	US
Kind code	B2
Filing date	Sep 10, 2014
Priority date	Oct 8, 2013
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

A fuel cell system supplies anode gas and cathode gas to a fuel cell and causes the fuel cell to generate electric power in accordance with a load. The fuel cell system includes a container reserved impurities discharged from the fuel cell. The fuel cell system includes a pressure control unit that makes a pressure of the anode gas higher when a current of the fuel cell is high than when the current of the fuel cell is low. The fuel cell system includes an estimation unit that varies the current of the fuel cell, and estimates a current-voltage characteristic of the fuel cell on the basis of a current value and a voltage value obtained when the current of the fuel cell has been varied. The fuel cell system includes a restriction unit that, while the estimation unit is estimating the current-voltage characteristic, restricts a reduction in the pressure of the anode gas.

First claim

The invention claimed is:

1. A fuel cell system for supplying anode gas and cathode gas to a fuel cell and for causing the fuel cell to generate electric power in accordance with a load, the fuel cell system comprising:
a container configured to reserve impurities discharged from the fuel cell;
a pressure control unit configured to make a pressure of the anode gas higher when a current of the fuel cell is high than when the current of the fuel cell is low;
an estimation unit configured to vary an amplitude of the current of the fuel cell, and estimate a current-voltage characteristic of the fuel cell on the basis of a current value and a voltage value obtained when the amplitude of the current of the fuel cell has been varied; and
a restriction unit configured to, while the estimation unit is estimating the current-voltage characteristic, restrict a reduction made by the pressure control unit in the pressure of the anode gas.

2. The fuel cell system according to claim 1 , wherein
while the estimation unit is varying the current of the fuel cell, the restriction unit sets the pressure of the anode gas to a predetermined pressure.

3. The fuel cell system according to claim 2 , wherein
the predetermined pressure is set on the basis of an upper limit value for an increase made by the estimation unit in the current of the fuel cell.

4. The fuel cell system according to claim 2 , wherein
on a basis of the predetermined pressure, the restriction unit causes the pressure of the anode gas to pulsate in accordance with a predetermined pulsation restriction amplitude smaller than a pulsation amplitude necessary for discharging generated water included in the impurities.

5. The fuel cell system according to claim 4 , wherein
the pulsation restriction amplitude smaller than the pulsation amplitude necessary for discharging the generated water is a pulsation amplitude necessary for discharging nitrogen gas.

6. The fuel cell system according to claim 2 , further comprising
a pulsation operation unit configured to cause the pressure of the anode gas to pulsate in accordance with a pulsation amplitude necessary for discharging generated water associated with the generation of electric power, wherein
while the estimation unit is varying the current of the fuel cell, the restriction unit switches the pressure of the anode gas from the pressure pulsated by the pulsation operation unit to the predetermined pressure.

7. The fuel cell system according to claim 2 , wherein
the estimation unit obtains the current value and the voltage value of the fuel cell when the current of the fuel cell is reduced, and
while the estimation unit is reducing the current of the fuel cell, the restriction unit sets the pressure of the anode gas to the predetermined pressure.

8. A method of controlling a fuel cell system for supplying anode gas and cathode gas to a fuel cell, and for causing the fuel cell to generate electric power in accordance with a load, the fuel cell system including a container for reserving impurities discharged from the fuel cell, the method comprising:
a pressure control step of making a pressure of the anode gas higher when a current of the fuel cell is high than when the current of the fuel cell is low;
an estimation step of varying an amplitude of the current of the fuel cell, and estimating a current-voltage characteristic of the fuel cell on the basis of a current value and a voltage value obtained when the amplitude of the current of the fuel cell has been varied; and
a restriction step of restricting, while the current-voltage characteristic is being estimated in the estimation step, a reduction made in the pressure control step in the pressure of the anode gas.

9. The fuel cell system according to claim 1 , wherein
the container is provided in an anode gas discharge passage.

Assignees

• Nissan Motor

Inventors

• Hoshi Kiyoshi

Classifications

• Y02T90/32

  Cross-Sectional Technologies · mapped topic

• H01M8/0662

  Treatment of gaseous reactants or gaseous residues, e.g. cleaning · CPC title

• H01M8/04082 Primary

  Arrangements for control of reactant parameters, e.g. pressure or concentration · CPC title

• H01M8/04291

  Arrangements for managing water in solid electrolyte fuel cell systems (H01M8/04119 takes precedence) · CPC title

• H01M8/04559 Primary

  of fuel cell stacks · CPC title