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
3Präsentation externKonzernforschung
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
4Präsentation externKonzernforschung
H2-Infrastructure Demonstration Project - Solar Filling Station Isenbüttel
7 kW Photovoltaic Plant
Electrolyser
Pressure Vessel
Solar-Power
5Präsentation externKonzernforschung
Fuel Cell Propulsion 1 st GenerationExample: System Survey of VW Touran HyMotion
Electric Engine
HydrogenTank
NiMH-Battery
Fuel Cell
6Präsentation externKonzernforschung
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)
7Präsentation externKonzernforschung
Fuel Cell 1 st Generation vs. Combustion EngineCooler Performance Highway (Simulation)
......
...
Fuel CellFuel Cell CombustionEngine
CombustionEngine
Exhaust
Cooling 49 %
6 %
20 %
36 %
Heat-Losses
8Präsentation externKonzernforschung
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
9Präsentation externKonzernforschung
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
10Präsentation externKonzernforschung
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
11Präsentation externKonzernforschung
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
12Präsentation externKonzernforschung
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…
13Präsentation externKonzernforschung
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
14Präsentation externKonzernforschung
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
15Präsentation externKonzernforschung
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
16Präsentation externKonzernforschung
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
17Präsentation externKonzernforschung
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
18Präsentation externKonzernforschung
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
19Präsentation externKonzernforschung
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
20Präsentation externKonzernforschung
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
21Präsentation externKonzernforschung
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
22Präsentation externKonzernforschung
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
23Präsentation externKonzernforschung
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
24Präsentation externKonzernforschung
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
25Präsentation externKonzernforschung
Molecular Modeling of High Temperature MEA/membraneswelling behavior of membrane in acid
Increasing acid content in membrane
26Präsentation externKonzernforschung
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)
27Präsentation externKonzernforschung
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
28Präsentation externKonzernforschung
Thank You!
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