State estimation device and method for fuel cell and fuel cell system

Patent metadata

Field	Value
Publication number	US-11054473-B2
Application number	US-201415518317-A
Country	US
Kind code	B2
Filing date	Oct 30, 2014
Priority date	Oct 30, 2014
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

A state estimation device for a fuel cell for generating power upon receiving the supply of anode gas and cathode gas, comprising: an internal impedance measurement unit configured to measure an internal impedance of the fuel cell on the basis of an alternating-current signal of a predetermined frequency output from the fuel cell; a state quantity preliminary estimation value calculation unit configured to calculate a first preliminary estimation value for a state quantity of an electrode obtained from a real component of a measurement value of the internal impedance and a second preliminary estimation value for the state quantity of the electrode obtained from an imaginary component of the measurement value of the internal impedance; and a state quantity final estimation value determination unit configured to determine a final estimation value of the state quantity of the electrode on the basis of the calculated first and second preliminary estimation values.

First claim

The invention claimed is:

1. A state estimation device for a fuel cell for generating power upon receiving supply of anode gas and cathode gas, comprising
a processor programmed to:
measure an internal impedance of the fuel cell on the basis of an alternating-current signal of a predetermined frequency output from the fuel cell;
calculate first preliminary estimation values of a reaction resistance and an electrical double layer capacitance of an electrode obtained from an imaginary component of a measurement value of the internal impedance on the basis of an equation for an imaginary component of the internal impedance, the equation being determined by an equivalent circuit model of the fuel cell;
calculate second preliminary estimation values of the reaction resistance and the electrical double layer capacitance of the electrode obtained from a real component of the measurement value of the internal impedance on the basis of an equation for a real component of the internal impedance;
determine a final estimation value of the reaction resistance of the electrode on the basis of the calculated first and second preliminary estimation values of the reaction resistance;
determine a final estimation value of the electrical double layer capacitance on the basis of the calculated first and second preliminary estimation values of the electrical double layer capacitance; and
detect an abnormal state of the fuel cell on the basis of the final estimation value of the reaction resistance and/or the final estimation value of the electrical double layer capacitance.

2. The state estimation device for the fuel cell according to claim 1 , wherein:
the processor is programmed to determine a larger one of the first and second preliminary estimation values of the reaction resistance as a final estimation value of the reaction resistance.

3. The state estimation device for the fuel cell according to claim 1 , wherein:
the processor is programmed to:
obtain a first preliminary estimation value R act1 of the reaction resistance using frequencies ω 1 , ω 2 and measurement values Z im1 and Z im2 of imaginary components of internal impedances corresponding to respective frequencies ω 1 , ω 2 on the basis of the following equation for an imaginary component Z im of the internal impedance determined by an equivalent circuit model of the fuel cell:

[

Equation
⁢

⁢
1

]

⁢

⁢

-

1

ω
⁢

⁢

Z
im

=

1

ω
2

⁢

C

dl
⁢

⁢
1

⁢

R

act
⁢

⁢
1

2

+

C

dl
⁢

⁢
1

where Z im denotes the imaginary component of the internal impedance of the fuel cell and ω denotes an angular frequency of the alternating-current signal, and C dl1 denotes a first preliminary estimation value of the electrical double layer capacitance; and
obtain a second preliminary estimation value R act2 of the reaction resistance using the frequencies ω 1 , ω 2 , measurement values Z re1 and Z re2 of real components of the internal impedances corresponding to the respective frequencies ω 1 , ω 2 and an electrolyte membrane resistance R m calculated in advance on the basis of the following equation for a real component Z re of the internal impedance determined by the equivalent circuit model of the fuel cell:

[

Equation
⁢

⁢
2

]

⁢

1

Z
re

-

R
m

=

ω
2

⁢

C

dl
⁢

⁢
2

2

⁢

R

act
⁢

⁢
2

+

1

R

act
⁢

⁢
2

where C dl2 denotes a second preliminary estimation value of the electrical double layer capacitance.

4. The state estimation device for the fuel cell according to claim 3 , wherein:
the first preliminary estimation value R act1 of the reaction resistance is obtained on the basis of a gradient and an intercept of a straight line obtained by connecting two points plotted on a coordinate system with 1/ω 2 represented on a horizontal axis and −1/(ω·Z im ) represented on a vertical axis, using the frequencies ω 1 , ω 2 and the measurement values Z im1 and Z im2 of the imaginary components of the internal impedances; and
the s

Assignees

• Nissan Motor

Inventors

• Aoki Tetsuya

Classifications

• H01M8/04649 Primary

  of fuel cell stacks · CPC title

• G01N27/02

  by investigating impedance · CPC title

• H01M8/04679

  of fuel cell stacks · CPC title

• Y02T90/40

  Application of hydrogen technology to transportation, e.g. using fuel cells · CPC title

• Y02E60/50

  Fuel cells · CPC title