High-temperature PEM Fuel Cells - HZG · 2008. 2. 12. · LT-PEM-FC (Low Temperature Proton Exchange Membrane Fuel Cell) PAFC (Phosphoric Acid Fuel Cell) 100 0 AFC (Alkaline Fuel

19.06.2007Konzernforschung

High-temperature PEM Fuel CellsDr. Gerold Hübner

2Präsentation externKonzernforschung

Volkswagen’s Fuel- and Powertrain Strategy

From Oil

From

Gasoline

Cellulose-Ethanol

SynFuel

Hydrogen

TDI/TSI

Hybrid

CCSSunFuel ®

Diesel Fuel

(regenerative)Fuel CellRenewable

Electricitytraction

Electro-

Natural Gas


Isenbüttel technology center (TZI)

13.0

0

55 / 9

13. 00

Flaeche ca . 37900 qm

5/ 11

55 / 10

4 / 10

4/ 2

8/ 1

13. 00

3 .0 0

3 . 00

R = 13

R = 47

3 .00

Feuerwehrumfahrt Erweiterung

56 . 6 3

56 . 4 8

56 . 3 3

56 . 1 8

57. 0 75

57. 315

57. 59 3

5 7. 947

58. 2 25

58. 52 5

5 8. 825

5 8. 75

58 . 4 5

58 . 1 5

57. 872

57. 5 93

57. 4 25

5 7. 1 85

5 6. 31

5 6. 46

5 6 .6 1

56 .7 6

Fahrrõder 20 EP

139 EP

BAUTEI L A - B▄ROGEB─UDE

I I

OK ATTI KA = ( +7 . 44 = 64 . 54 ³ .NN)

HALL EN I N PLANUNG

Feuerwehrumfahrt

- 0. 02 =

57. 08

TORANL AGE

VORFAHRT

RANDSTREI FEN KLETTERPFLANZEN, 5 0 cm

ANLI EF ERUNG

M▄LL

TORANL AGE

ERSCHL

I ESSUN

GSSTRA

SSE

VEREI NZELUNGSANL AGE

REGENR▄CKHALTEBECKEN

M▄LL

BAUGRENZE

ERWEITERUNGSMÍGLICHKEIT HALLEN

ERWEITERUNGSMÍGLICHKEIT B▄ROGEB─UDE

15.34

14.73

15.34

14.73

15.34

75.48

27.33 75

15.17 25

12.16 5

27.80 94

24.00 43

36.80 64

44.98 65

69.02 92

72.13 86

hall

1ha

ll 2

hall

3

office

ca.

ca.

ca.

Site size

Hall area

Office area

38.000 m²

6.800 m²

2.800 m²


H2-Infrastructure Demonstration Project - Solar Filling Station Isenbüttel

7 kW Photovoltaic Plant

Electrolyser

Pressure Vessel

Solar-Power


Fuel Cell Propulsion 1 st GenerationExample: System Survey of VW Touran HyMotion

Electric Engine

HydrogenTank

NiMH-Battery

Fuel Cell


Fuel Cell Vehicles 1 st GenerationInternational Exhibition

■ 85 kW Fuel Cell System■ High Power NiMH-Battery■ 80 kW Electric Engine■ 2.6 kg Hydrogen (350 bar)

CaFCPRoad Rallye 4

(2005)

Accession CEP(2006)

CaFCPRoad Rallye 3

(2004)

Challenge Bibendum

(2004)Inauguration Sacramento

(2000)


Fuel Cell 1 st Generation vs. Combustion EngineCooler Performance Highway (Simulation)

......

...

Fuel CellFuel Cell CombustionEngine

CombustionEngine

Exhaust

Cooling 49 %

6 %

20 %

36 %

Heat-Losses


Energy Balance for Fuel Cell Automobile 1 st GenerationExample: VW Touran HyMotion (Simulation/Measurement)

0 20 40 60 80 100 120 140 160 180 200 220

160

140

120

100

80

60

40

20

0

Speed [km/h]

Tra

nfer

able

Hea

tFlo

w[k

W]

Top Speed ≈ 49 km/h Top Speed ≈ 49 km/h

Top Speed ≈ 136 km/h Top Speed ≈ 136 km/h

No Gra

dient

Basis: Touran (Serial Car Body, 1700 kg, cw*A = 0.78 7)FC-Operation Temperature: 80 °C (LT- Membrane)

Tenv = 40 °C

6% Gra

dientTransferable Heat Flow

Transferred Heat Flow

PEM- BZ80°C

PEM- BZ80°C


0

10

20

30

40

50

60

70

80

90

100

20 40 60 80 100 120

operation temperature [°C]

wat

er d

eman

d [k

g/h]

Temperature dependent Humidification demand

Impacts on fuel cell system:

• Additional control demand

• system complexity

• Lack of system reliability

Characteristic of state of the art proton exchange membr anesHumidification demand

water neutral product water

objective:

Humidification free MEA

water demand


performance drop at stop of humidification

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

24,7 25,2 25,7 26,2 26,7

operation time

pero

rman

ce d

ensi

ty [W

/cm

²]

0

25

50

75

100

humidification in %

Performance drop at stop of humidification

complete break-in of perfor-mance

irreversible damage of MEA

mechanical shrinking of membrane:

- Dissolution of electrode

- mechanical cracking at interface

Characteristic of state of the art proton exchange membr anesHumidification demand


PEM-FC (Proton Exchange Membrane Fuel Cell)

PAFC (Phosphoric Acid Fuel Cell)

100

0

AFC (Alkaline Fuel Cell)

5015

0

180 °C

60 °C

80 °C

App

licat

ion

in A

utom

obile

Characteristic of state of the art proton exchange membr anesFuel Cells for Automobile Propulsion


160 °C

80 °C

PBI/H3PO4

Automotive MEA

Dry gases

Modified sPFSA

Humidified Gases

Innovative concepts

Intrinsic proton conductivity

Production readiness

Increase of Tg, water reservoir, increase of IEC

membrane- /elektrodemodification

Dry operation

Up to 130 °C

Innovative approaches for proton exchange membranesFuel Cells for Automobile Propulsion

Immobilisedproton solvents,Immidazole…


C H F

O

C F 2

F C C F 3

O

C F 2

C F 2

S O 3

F 2C

F 2C

F 2C*

x y

O

H

HH

OHH

OHH

OHH

OHH

C H F

O

C F 2

F C C F 3

O

C F 2

C F 2

S O 3

F 2C

F 2C

F 2C*

x y

N

N

N

N

H

H

H

H

P

O-

HO

OOH

P

OHO

HOOH

P

OHO

-OOH

H+

P

OHO

HOOH

P

OHO

HOOH

PerFluoroSulfonate Ionomer Nafion® (DuPont) PBI (Polybenzimidazol)/H3PO4

State of the art: water based proton conductivity: water acting as electrolyte

High Temperature Membrane: dry protonconductivity: High boiling electrolyte

Innovative approaches for proton exchange membranesthe Volkswagen High Temperature MEA

US 5525436

DE 29522223

US 6099988


LT-PEM-FC (Low Temperature Proton Exchange Membrane Fuel Cell)

PAFC (Phosphoric Acid Fuel Cell)

100

0

AFC (Alkaline Fuel Cell)

5015

0

180 °C

60 °C

80 °C

App

licat

ion

in A

utom

obile

HT-PEM-FC (High Temperature Proton Exchange Membrane Fuel Cell)160 °C

Innovative approaches for proton exchange membranesthe Volkswagen High Temperature MEA


Component validation

Siebdruckverfahren

Volkswagen fuel cell test and research

VW HT electrode development

Exclusive development project VW HT MEA

Wordwide initiation and screening

Funded projects on international level

Component tests at „automotive“ conditions

Optimum adaption to:

- membrane material

- operation conditions

- performance goals


Siebdruckverfahren

Fuel cell test field

Gen 1 Gen 2

Gen 3

Fullfilling power demands

from 10 cm² single cell to

100 kW automotive stack tests

+ cold start tests

Fuel cell stack developmentIdentification of appropriate materials

Simulation

manufacturing

Volkswagen fuel cell test and research


Breakthrough of the Volkswagen High Temperature MEATemperature Cycleability

0

0,1

0,2

0,3

0,4

0,5

0,6

700 710 720 730 740 750 760 770 780 790 800

time [h]

perf

orm

ance

[W/c

m²]

„Weltneuheit aus Isenbüttel“

160°C

40°C


0,0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

time [h]

perf

orm

ance

den

sity

at 0

,6 V

[W/c

m²]

Volkswagen HT-MEA

Standard HT-Membran (H3PO4-Membrane PBI MEA)

Accelerated temperature cycle2 h @ 0.6 V: 160 °C2 h @ 0.6 V: 40 °C

Degradation6 % in 1000 h

Breakthrough of the Volkswagen High Temperature MEA Temperature Cycleability


Commercial HT-Membrane

2002 2003 2004 2005 2006 2007

1,21,1

10,90,80,70,60,50,40,30,20,1

0

Per

form

ance

at 0

,6 V

[W

/cm

2 ]

Single cell 10 cm²

Commercial LT-Membrane

Performance density [W/cm²] (0,6 V)

NT HTZelle Stack Zelle Stack1,15 0,9 0,9 0,45

Breakthrough of the Volkswagen High Temperature MEA Performance: 0,6 V; 3 bar

160°C


commercial HT-Membrane

2005 2006 2007

0,30

0,25

0,20

0,15

0,10

0,05

0Leis

tung

sdic

hte

bei 0

,6 V

in W

/cm

2 commercial LT-Membrane

Breakthrough of the Volkswagen High Temperature MEA Performance: 0,6 V; 3 bar; 40 °C

Single cell 10 cm²

40°C


0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9

1,2

1,0

0,8

0,6

0,4

0,2

0,0

0,7

0,6

0,5

0,4

0,3

0,2

0,1

0,0

Current density [A/cm²]

Vol

tage

per

cell

[V]

pow

erde

nsity

[W/c

m²]

Voltage/current

Performance current

HT Fuel Cell Stack PerformanceHT-stack – 15 cell, 200 cm²


0

10

20

30

40

50

60

70

80

0 2000 4000 6000 8000 10000 12000 14000

Zeit [min]cu

rren

t [A

]

-30

-20

-10

0

10

20

30

40

50

Strom NT (80°C)

Strom HT (160°C)

10 ppm

10 ppm

1000 ppm100 ppm

0

5

10

15

20

25

30

35

40

45

50

0 2000 4000 6000 8000 10000 12000 14000

Zeit [min]

curr

ent

[A]

Strom HT (160°C)

Strom NT (80°C)

0.1ppm

10ppm

1ppm

0.1ppm

1ppm

10ppm

SO2CO

Volkswagen High Temperature MEAcathode contamination, initial findings


Further optimization of VW High Temperature MEAelectrode manufacturing process

- Evaluation of different manufacturing processes

- Up scaling to large cell areas

- Paste composition

- new catalyst compositions (e.g. alloys)

- reduction of catalyst loading


Molecular Modeling of High Temperature MEA/membraneprediction of polymer and electrolyte properties

- Glass transition temperature

- mechanical properties

- swelling behaviour

- prediction of new polymer/electrolyte properties

- prediction of polymer – electrolyte interaction


Molecular Modeling of High Temperature MEA/membraneswelling behavior of membrane in acid

Increasing acid content in membrane


Technology evaluation

Year2005 20202000 2010 20151995

LT-BZ

HT-BZ (V

W)

Target Area of Ability for Mass Market

Per

form

ance

Cos

ts/M

ass/

Vol

ume/

Rel

iabi

lity

LT = Low Temperature Fuel Cell (Based on Nafion)HT = High Temperature Fuel Cell (Technology of VW)


Next steps

Still existing technological challenges of the exis ting high temperature MEA technology:

•Low temperature and cold start ability

•Scale Up (mechanical stability at high acid loading)

•Cathode losses

•Electrode/membrane contact

•Temperature stability of stack materials


Thank You!

Documents

High-temperature PEM Fuel Cells - HZG · 2008. 2. 12. · LT-PEM-FC (Low Temperature Proton Exchange Membrane Fuel Cell) PAFC (Phosphoric Acid Fuel Cell) 100 0 AFC (Alkaline Fuel