Method for optimization of fuel cells operating conditions using hybrid model

Patent metadata

Field	Value
Publication number	US-10108759-B2
Application number	US-201414283524-A
Country	US
Kind code	B2
Filing date	May 21, 2014
Priority date	Mar 28, 2014
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

Provided is a method for optimization of fuel cells operating conditions using a hybrid model, and more particularly, a method for optimization of fuel cells operating conditions using a hybrid model which generates a life prediction model determined by time and temperature based on a theoretical performance model and an empirical durability model and estimates an optimal operation temperature in a target life based on the life prediction model.

First claim

What is claimed is:

1. A method for adjusting operating conditions of a fuel cell with an aid of a computing device including an empirical durability model generating unit, an optimal operation temperature estimating unit, and a memory including executable instructions stored thereon, the method comprising:
obtaining a potential difference depending on a current density of a cell based on a thermodynamics reversible voltage, an activity loss, a resistance loss, and a concentration loss of a high temperature proton-exchange membrane fuel cell (PEMFC) including a polybenzimidazole (PBI) membrane with which phosphoric acid is doped (S 10 );
generating an empirical durability model which predicts a reduction in cell voltage over an operation time at a predetermined temperature (S 20 ) at the empirical durability model generating unit;
determining an optimal operation temperature at a target life based on the potential difference depending on a current density of the PEMFC (S 10 ) and the durability model generated in the generating of the empirical durability model (S 20 ) (S 40 ) at the optimal operation temperature estimating unit; and
adjusting an operation temperature of the PEMFC to the optimal operation temperature,
wherein the generating of the durability model (S 20 ) includes:
generating a draft model predicting the reduction in cell voltage over the operation time at the predetermined various temperatures while ruling out an effect of the operation time (S 21 );
performing a durability test of the PEMFC which detects the reduction in cell voltage for a predetermined period at the predetermined various temperatures;
estimating coefficients of the draft model over various times generated in the generating of the draft model (S 21 ) based on the reduction in cell voltage detected in the durability test of the PEMFC (S 22 ); and
generating a third-order non-linear function depending on the operation time and temperature using the coefficients estimated in the estimating of the coefficient (S 22 ) (S 23 ), and
wherein for each of the predetermined various temperatures, the draft model in the generating of the draft model (S 21 ) predicts the reduction in cell voltage over the operation time using the draft model corresponding to the following Equation:
VD ( t )= x 1 t 3 −x 2 t 2 +x 3 t+x 4 , and

a final model which is used at the durability model is to fit the four coefficients x 1 , x 2 , x 3 , and x 4 of the draft model depending on the operation temperature.

2. The method of claim 1 , wherein the potential difference depending on a current density of the PEMFC is obtained by subtracting the activity loss, the resistance loss, and the concentration loss from the thermodynamics reversible voltage based on the following Equation:
E cell =E rev −η act −η ohm −η conc

In the above Equation, E cell represents the potential difference depending on a current density of the PEMFC, E rev represents the thermodynamics reversible voltage, η act represents the activity loss, η ohm represents the resistance loss and η conc represents the concentration loss.

3. The method of claim 2 , wherein the thermodynamics reversible voltage is calculated based on the following Equation,

E
ref

=

-

Δ
⁢

⁢

g
rnx
ref

n
⁢

⁢
F

.

In the above Equation, Δg rnx ref represents Gibbs' free energy and F represents a Faraday constant and n represents number of transfer electrons,
the thermodynamics reversible voltage at a given temperature T is calculated based on the following Equation by introducing a change in entropy depending on temperature,

E
T

=

E
ref

+

Δ
⁢

⁢
s

n
⁢

⁢
F

⁢

(

T
-

T
ref

)

.

In the above Equation, Δs represents the change in entropy depending on the temperature and T ref represents reference temperature,
when a concentration of chemical species is specified, the thermodynamics reversible voltage is calculated based on the following Equation by introducing activity, and

E
rev

=

E
ref

-

RT

n
⁢

⁢
F

⁢
ln
⁢

⁢

a

H
2

⁢
O

a

H
2

⁢

a

O
2

0.5

.

In the above Equation, R represents an abnormal gas constant and a represents activity, and
at the given temperature T and conce

Assignees

• Korea Inst Energy Res

Inventors

• Kim Minjin
• Sohn Young-Jun
• Park Gu-Gon
• Bae Byungchan
• Yim Sung-Dae
• Choi Young-Woo
• Park Seok-Hee
• Yang Tae-Hyun
• Lee Won-Yong
• Kim Chang-Soo

Classifications

• H01M8/04552

  of the individual fuel cell · CPC title

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/04305 Primary

  Modeling, demonstration models of fuel cells, e.g. for training purposes · CPC title

• H01M8/04544

  Voltage · CPC title

• G06F30/20 Primary

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title