Control method and system for stop mode of fuel cell

Patent metadata

Field	Value
Publication number	US-2018294498-A1
Application number	US-201715820901-A
Country	US
Kind code	A1
Filing date	Nov 22, 2017
Priority date	Apr 11, 2017
Publication date	Oct 11, 2018
Grant date	—

Abstract

The present invention relates to a method and system for controlling a stop mode of a fuel cell. In particular, the present invention provides a method and system for controlling a stop mode of a fuel cell which are characterized by calculating the degree of deterioration of a fuel cell, determining a stopping voltage in accordance with the calculated degree of deterioration, and controlling an output voltage of the fuel cell to be the determined stopping voltage.

First claim

What is claimed is:

1 . A method of controlling a stop mode of a fuel cell, the method comprising:
calculating a degree of deterioration of the fuel cell; determining a stopping voltage of the fuel cell in accordance with the calculated degree of deterioration; determining whether the fuel cell has entered the stop mode; and controlling an output voltage of the fuel cell to be the determined stopping voltage when it is determined that the fuel cell has entered the stop mode.

2 . The method of claim 1 , wherein in the calculating of a degree of deterioration, the degree of deterioration of the fuel cell is calculated using a degree of oxidization of a cathode catalyst of the fuel cell.

3 . The method of claim 2 , wherein in the calculating of a degree of deterioration, the degree of oxidization of the cathode catalyst of the fuel cell is updated and stored in a nonvolatile memory.

4 . The method of claim 2 , wherein the degree of oxidization of the cathode catalyst is estimated from the following equations in the determining of a degree of deterioration,

d




θ
PtOx

dt

=

k
PtOx

(

(

1
-

θ
PtOx

)



exp
(

α
a
′


F

RT



η
PtOx

)

-

θ
PtOx



exp
(

-

α
c
′


F

RT



η
PtOx

)

)

η
PtOx

=

Φ
C

-

Φ
ion

-

U
PtOx

θ PtOx : degree of oxidization of cathode platinum catalyst (0˜1)
η PtOx : potential difference at cathode
k PtOx : reaction rate for PtOx formation
α′ α , α′ c : anodic and cathodic transfer coefficient for PtOx formation
U PtOx : PtOx equilibrium potential
ϕ C : measured voltage of cell of fuel cell (average for a plurality of cells)
ϕ ion : potential loss of electrolytic membrane
U PtOx : equilibrium voltage
F: Faraday constant
R: ideal gas constant
T: temperature (K)

5 . The method of claim 1 , wherein in the determining of a stopping voltage, the calculated degree of deterioration is compared with a predetermined value and one of a plurality of stopping voltages stored in advance is selected in accordance with the comparing result.

6 . The method of claim 1 , wherein in the determining of a stopping voltage, the stopping voltage is determined such that the larger the calculated degree of deterioration, the lower the stopping voltage.

7 . The method of claim 1 , wherein in the determining of a stopping voltage, the stopping voltage is determined such that the smaller the calculated degree of deterioration, the higher the stopping voltage.

8 . The method of claim 1 , wherein in the determining of whether the fuel cell has entered the stop mode, whether the stop mode has been entered is determined in accordance with whether requested output exists.

9 . A system for controlling a stop mode of a fuel cell, comprising:
a deterioration calculating unit calculating a degree of deterioration of a fuel cell; a stopping voltage determining unit determining a stopping voltage of the fuel cell on the basis of the degree of deterioration of the fuel cell calculated by the deterioration calculating unit; a stop mode entrance determining unit determining whether the fuel cell has entered the stop mode; and a power distribution control unit controlling an output voltage of the fuel cell to be the stopping voltage determined by the stopping voltage determining unit when the stop mode entrance determining unit determines that the fuel cell has entered the stop mode.

10 . The system of claim 9 , further comprising an oxidization estimating unit estimating a degree of oxidization of a cathode catalyst of the fuel cell,
wherein the deterioration calculating unit calculates the degree of deterioration of the fuel cell from the degree of oxidization of the cathode catalyst of the fuel cell estimated by the oxidization estimating unit.

11 . The system of claim 10 , wherein the oxidization estimating unit includes a nonvolatile memory for updating and storing the degree of oxidization of the cathode catalyst.

12 . The system of claim 9 , wherein a reference deterioration degree and a plurality of stopping voltages are stored in advance in the stopping voltage determining unit, and the stopping voltage determining unit determines the stopping voltage by comparing the degree of oxidization of the fuel cell calculated by the deterioration calculating unit with the reference deterioration degree and selecting one of the stopping voltages stored in advance in accordance with the comparing result.

13 . The system of claim 9 , wherein the stopping voltage determining unit determines the stopping voltage such that the larger the degree of deterioration calculated by the deterioration calculating unit, the lower the stopping voltage, and determines the stoppi

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Suh Kyung Won

Classifications

• H01M2250/10

  Fuel cells in stationary systems, e.g. emergency power source in plant · CPC title

• H01M8/04664

  Failure or abnormal function · CPC title

• H01M8/04992 Primary

  characterised by the implementation of mathematical or computational algorithms, e.g. feedback control loops, fuzzy logic, neural networks or artificial intelligence · CPC title

• H01M8/04552

  of the individual fuel cell · CPC title

• H01M8/04679

  of fuel cell stacks · CPC title