FRM 5101460 AFCC Research Needs Analysis for Generation 4 Vehicles.
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FRM5101460
AFCC Research Needs Analysisfor Generation 4 Vehicles
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Future GenerationsFuture Generations
Generation 1Technology Demonstration
F-Cell
Generation 2Customer Acceptance
B-Class F-Cell
Generation 3Cost Reduction I
Generation 4Market Introduction
Cost Reduction II
Passenger CarsLead application
Generation 1Technology Demonstration
Generation 2Customer Acceptance
Bus
Generation 1Technology Demonstration
Generation 2Customer Acceptance
Sprinter
Generation 5High Volume
Series Production
2004
2010
2013
201x
202y
Fuel Cell Roadmap - The Path to Commercialization
Fuel cell passenger cars will drive the volume
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Status of Fuel Cell Technology
PerformanceSafetyComfortFreeze startRange
ReliabilityLongevityPackage/weightCost
Generation 3 Cars will demonstrate competitive capabilities.
Cost remains the challenge!
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5 Basic Strategies For Cost Reduction
Detailed examination of all 5 areas will indicate the best paths for further improvement.
Investment of development dollars
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Mining For Cost Reduction
Given multiple options a good miner:• Drills new test holes.• Explores a few high risk/high gain paths.• Exploits the known paths fully in order of their value.• Saves some lower value ore bodies for later exploration.• Knows when a ore body is exhausted.
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Distillation
Technology Area
Driver Size Dura Fuel Econ
Cost Criticality Understanding
Opportunity
Classification
0.1 0.2 0.3 0.4
Catalyst Catalyst Coating Technology 1 3 3 2.3 Med Med Engineering Catalyst Catalyst Primary Process 3 1.2 Low High ResearchCatalyst Catalyst Recycling Process 1 0.4 Low High ResearchCatalyst Freeze tolerant Catalyst Structure 3 1 1 Med Med Research
Catalyst Carbon supported Pt 9 9 9 9 9 High Low Technoloy at Limit
Catalyst New High Activity Catalyst 9 9 9 9 9 Low High High Priority ResearchCatalyst Less Platinum 1 9 9 9 8.2 High Med High Priority ResearchCatalyst Non Carbon Catalyst Support Materials 9 3 3 3.9 Low High High Priority ResearchCatalyst Pt Dissolution Resistant Catalyst 9 3 9 6.3 Med Med High Priority ResearchCell Design Better Mechanical Integration 9 0 3 2.1 Med Med EngineeringCell Design Higher Stack Peak T 3 3 9 4.5 High Med EngineeringCell Design Low Force Seals 9 3 1.5 High Low Technoloy at LimitCell Design Low Pressure Drop Anode FFs 3 3 3 3 3 High Med EngineeringCell Design Minimize Port Areas 3 3 1.5 High Low Technoloy at LimitCell Design Minimize transition areas 3 3 1.5 High Low Technoloy at Limit
Cell Design Near Dead Ended Cells 3 3 3 3 3 Med Med ResearchCell Design Robustness of design to MFG tols 1 3 3 1 2 High Low Technoloy at LimitCell Design Self Hydrating Cell 3 9 3 3 4.2 High Low Technoloy at LimitCell Design Smaller Seal Foot Print 1 3 1.3 High Low EngineeringFCS Ability to Boost Voltage from Stack 3 9 3.9 High High EngineeringFCS Efficient Air Compressor Technology 3 3 9 9 7.2 High Med High Priority ResearchFCS Higher Temperature Humidifiers 3 1.2 Low High ResearchFCS Less Expensive Humidifiers 3 9 9 3 6 Med High High Priority ResearchFCS Less Expensive H2 pump 3 3 3 2.7 Med Med EngineeringFCS Less Expensive Intercooler 1 0.4 High Low Technoloy at LimitFCS ( vehicle) Less Gross Power 3 9 9 6.6 High High EngineeringTechnology Area
Driver Size Dura Fuel Econ
Cost Criticality Understanding
Opportunity
Classification
GDL Improved GDL Pore Structure 9 3 1 9 5.4 Med High High Priority ResearchGDL Freeze tolerant GDL Structure 1 3 3 1.9 Med Med ResearchGDL GDL Additive Materials 1 1 1 0.9 High Med EngineeringGDL GDL Additive Processes 1 1 1 0.9 Med Med EngineeringGDL GDL Degradation 3 0.6 Med Med EngineeringGDL GDL low Cost Substrate Materials 3 3 3 9 5.4 Med Med EngineeringGDL GDL Microporous Layer Process 1 1 0.7 Med High EngineeringGDL GDL Substrate Mfg Process 3 1.2 Med Med EngineeringGDL Improved Water Mgmt in GDL 3 3 1 9 4.8 Med High ResearchGDL Maximize GDL Stiffness 9 3 1 9 5.4 Med Low EngineeringGDL Minimize GDL Thickness 3 3 1 1.3 High Low Technoloy at LimitGDL More Conductive GDL 1 3 1.3 Med Low EngineeringMembrane Conductivity @ <20% RH 3 9 9 6.6 High Low Technoloy at LimitMembrane Conductivity @ >80% RH 3 3 3 2.4 High Med ResearchMembrane Conductivity @ 20% to 80% RH 3 3 3 2.4 High Med ResearchMembrane Fundamentally less expensive polymers 3 3 9 5.1 Low High High Priority ResearchMembrane Less expensive PFSA precursors 3 1.2 High Med EngineeringMembrane Low H2 Cross Over Membrane 3 9 3 4.5 Med Low ResearchMembrane Low N2 Cross over membrane 9 9 6.3 Med Low High Priority ResearchMembrane Manufacturing Process 1 3 1.4 High Med EngineeringMembrane Membrane Loss ( degradation) 9 1 2.2 Med Med EngineeringMembrane Minimize Membrane Thickness 1 3 3 3 2.8 High Low Technoloy at LimitTechnology Area
Driver Size Dura Fuel Econ
Cost Crit Under. Opp Classification
Plate Increased Plate Conductivity 3 1 3 1.8 High Low Technoloy at LimitPlate Precise Plate Mfg Tolerances 1 3 3 1.9 High Low Technoloy at LimitPlate Carbon plate Cycle Time 3 1.2 Med High EngineeringPlate Carbon raw materials Processing 3 1.2 Med Med EngineeringPlate Facile Liquid Water Removal 1 3 9 3 4.6 High Med High Priority ResearchPlate Improved Plate Formability 3 1 3 9 5 High Med High Priority ResearchPlate Increased Plate Strength 3 3 0.9 High Low Technoloy at LimitPlate Metal Coating materials/process 3 9 3.9 Low Med High Priority ResearchPlate Metal or Carbon Joining Method 3 9 4.2 Med Med EngineeringPlate Metal Plate Substrate Alloy 3 3 1.8 High Med EngineeringPlate Minimize Plate Web Thickness 3 3 1.5 High Low Technoloy at LimitPlate Plate Corrosion Resistance ( metal only) 9 3 3 Low Med High Priority Research
Stack Cost
Durability Fuel Economy
StrategicFilter
Technology Area
Driver Criticality Understanding Opportunity
Catalyst Carbon supported Pt 9 High LowCatalyst New High Activity Catalyst 9 Low HighCatalyst Less Platinum 8.2 High MedFCS Efficient Air Compressor Technology 7.2 High MedFCS ( vehicle) Less Gross Power 6.6 High HighMembrane Conductivity @ <20% RH 6.6 High LowCatalyst Pt Dissolution Resistant Catalyst 6.3 Med MedMembrane Low N2 Cross over membrane 6.3 Med LowFCS Less Expensive Humidifiers 6 Med HighGDL Improved GDL Pore Structure 5.4 Med HighGDL GDL low Cost Substrate Materials 5.4 Med MedGDL Maximize GDL Stiffness 5.4 Med LowMembrane Fundamentally less expensive polymers 5.1 Low HighPlate Improved Plate Formability 5 High Med
Critical Research Needs
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Strategic Filter
1. Criticality• The criticality is the sum of the magnitudes of all the effects (good
or bad) of using a technology path.
2. Understanding• A measure of how much we know about a technology option
• Advantages, failure modes and trade-offs
3. Remaining Opportunity
Impro
vem
en
t
Effort
• How much improvement remains to be made along each technology path.
• If a path is fully mature we reach the “Technology Limit” and further improvement will require a “breakthrough” or the exploitation of a different path.
Technology Limit
Opportunity
Status
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Map of the Technology Mine (Cost)
•Technology At Limit Exploit in present design: diminishing returns
•High Priority Research Focus of academic and corporate research
•Research Lower urgency research
•Development Engineering Focus of in house and supplier engineering
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The Biggest Driver for Materials
•Technology At Limit Exploit in present design: diminishing returns
•High Priority Research Focus of academic and corporate research
•Research Lower urgency research
•Development Engineering Focus of in house and supplier engineering
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Some Statistics
Technology at Limit23%
Research17%
High Priority Research
22%
Engineering 38%
Opportunity
med46%
low32%
high22%
Understanding
Medium38% Low
13%
High49%
1. We should focus on the 23% that are most critical.
2. Overall understanding of the opportunities is good.
3. There are many good opportunities for cost reduction
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The Most Critical Research
These areas of research and development need to be the focus.
New durable high activity catalysts.
Enable low cost system
Enable high current density via plate and GDL
Lower cost cell materials
12
3
4
11
1
1
2
22
2
3
3
3
2
4
4
Technology Area
Driver Criticality Understanding Opportunity
Catalyst Carbon supported Pt 9 High LowCatalyst New High Activity Catalyst 9 Low HighCatalyst Less Platinum 8.2 High MedFCS Efficient Air Compressor Technology 7.2 High MedFCS ( vehicle) Less Gross Power 6.6 High HighMembrane Conductivity @ <20% RH 6.6 High LowCatalyst Pt Dissolution Resistant Catalyst 6.3 Med MedMembrane Low N2 Cross over membrane 6.3 Med LowFCS Less Expensive Humidifiers 6 Med HighGDL Improved GDL Pore Structure 5.4 Med HighGDL GDL low Cost Substrate Materials 5.4 Med MedGDL Maximize GDL Stiffness 5.4 Med LowMembrane Fundamentally less expensive polymers 5.1 Low HighPlate Improved Plate Formability 5 High Med
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The Mature Technologies
These technologies have reached their maximum capability.
• Gen 4 stack will utilize them at their maximum.
• It’s time to look for alternative paths or breakthroughs.
Technology Area
Driver Criticality Understanding Opportunity
Catalyst Carbon supported Pt 9 High LowCell Design Self Hydrating Cell 4.2 High LowCell Design Robustness of design to MFG tols 2 High LowCell Design Minimize Port Areas 1.5 High LowCell Design Minimize transition areas 1.5 High LowCell Design Low Force Seals 1.5 High LowFCS Less Expensive Intercooler 0.4 High LowGDL Minimize GDL Thickness 1.3 High LowMembrane Conductivity @ <20% RH 6.6 High LowMembrane Minimize Membrane Thickness 2.8 High LowPlate Precise Plate Mfg Tolerances 1.9 High LowPlate Increased Plate Conductivity 1.8 High LowPlate Minimize Plate Web Thickness 1.5 High LowPlate Increased Plate Strength 0.9 High Low
FRM5101460
Examples and Targets
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Catalyst
Carbon Supports - High surface area carbon supported Platinum catalysts have been the main technology in automotive PEM for the generation 1,2 and likely 3 stacks however they have essentially reached the limits of performance and durability and new path need to be explored for generation 4.
Activity vs Durability - For Pt based structures mass activity can be enhanced by increasing the surface area or by altering the electronic structure of the surface. Both options need to be pursued but the impact on durability is critical.
Processing - During the development of new catalyst systems we need to simultaneously develop the processes to synthesize them at low cost and possibly to deposit them directly onto MEA with as few intermediate steps as possible to ensure high material yields.
Technology Area
Driver Size Dura Fuel Econ
Cost Criticality
Understanding
Opportunity
Classification
Catalyst Carbon supported Pt 9 9 9 9 9 High Low Technology at LimitCatalyst New high activity catalyst 9 9 9 9 9 Low High High Priority ResearchCatalyst Less platinum 1 9 9 9 8.2 High Med High Priority ResearchCatalyst Pt dissolution resistant catalyst 9 3 9 6.3 Med Med High Priority Research
Catalyst Non carbon catalyst support materials 9 3 3 3.9 Low High High Priority Research
Catalyst Catalyst coating technology 1 3 3 2.3 Med Med Engineering Catalyst Catalyst primary process 3 1.2 Low High ResearchCatalyst Freeze tolerant catalyst structure 3 1 1 Med Med ResearchCatalyst Catalyst recycling process 1 0.4 Low High Research
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Cathode Catalyst Pathways
StabilizedPlatinum Alloys
Catalyst-Support
Interaction(Non-Carbon)
Pseudo BulkCatalyst
Non PreciousMetal Catalyst
Proprietary Process
Support Structures
Thin film Pt-alloy Structures
Various Materials
High Surface Area Metal oxides
Core Shell Catalysts
Work Streams
Create stable alloys that retain high performance
Improve activity w/ more robust support materials
Replace platinum with w/ cheap catalytic materials
High activity & stability
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Mass Activity/ Specific Activity
C=Carbon; HSC=High Surface Area Carbon
Ex-situ Activity Summary normalized to Pt baseline
1.0 1.4 1.64.5
23.8
10.3
????
1
1.9 2.1
3.42.6
3.9
????
0
5
10
15
20
25
30
Pt/C b
asel
ine
Pt-allo
y "A
" HSC
Pt-allo
y Sta
bilize
d HSC
Pt Allo
y "B
"/C
Pt/Met
al O
xide
Pt-Met
al O
xide/
C
Adv C
ore
Shell
High S
urfa
ce A
rea
Oxide
Sp
ecif
ic A
ctiv
ity
0
1
2
3
4
5
6
Sp
ecif
ic M
ass
Act
ivit
ySpecific Activity ( x Pt baseline)
Mass Activity ( x Pt baseline)
4x Mass Activity Target
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Membrane
Driver PFSA membranes are quite mature and it is becoming apparent that further improvements will be limited. They are however quite capable and are expected to be viable in future generations when the cost of producing them is reduced significantly.
Cross-over - In order to enable cost reduction in the fuel cell support systems a large reduction in the Nitrogen cross over is needed. Unless a change in the basic polymer is used to achieve this thinner membranes may not be practical.
Hydration - A great deal of effort has been put into reducing the resistance of membranes at low RH however this has increased the basic cost of the materials. Fundamental studies have shown that zero RH conduction cannot occur for sulphonic acid based membranes.
Membrane Conductivity @ <20% RH 3 9 9 6.6 High Low Technoloy at LimitMembrane Conductivity @ >80% RH 3 3 3 2.4 High Med ResearchMembrane Conductivity @ 20% to 80% RH 3 3 3 2.4 High Med High Priority ResearchMembrane Fundamentally less expensive polymers 3 3 9 5.1 Low High High Priority ResearchMembrane Less expensive PFSA precursors 3 1.2 High Med EngineeringMembrane Low H2 Cross Over Membrane 3 9 3 4.5 Med Low ResearchMembrane Low N2 Cross over membrane 9 9 6.3 Med Low High Priority ResearchMembrane Manufacturing Process 1 3 1.4 High Med EngineeringMembrane Membrane Loss ( degradation) 9 1 2.2 Med Med EngineeringMembrane Minimize Membrane Thickness 1 3 3 3 2.8 High Low Technoloy at Limit
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Additive Technology
Low cost PFSA membranes
Hydrocarbon membranes
Block Co-polymer
Low cost SSC PFSA
Free Radical Scavengers
Water Retention Additives
Work Streams
Improve membranes by adding special function materials.
Lower membrane cost, improve performance & durability.
Cost and better gas cross over.
Homo polymer
Reinforcement
Low cost LSC PFSA
Membrane Pathways
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Dry Conduction Progress
Membrane resistances for different RH's
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 20 40 60 80 100
Membrane RH (%)
Re
sis
tan
ce
(O
hm
.cm
2)
Supplier A
Supplier B
Supplier C
Target
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Dry Conduction Progress II Log Scale
Membrane resistances for different RH's
0.001
0.01
0.1
1
0 10 20 30 40 50 60 70 80 90 100
Membrane RH (%)
Re
sis
tan
ce
(O
hm
.cm
2)
Data from materials reported in the 2008 DOE Hydrogen program review
• Improved materials all have the same sensitivity to RH.• Overall resistance at all RHs improved• Without a change in conduction physics target at <30% RH unlikely to be met
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Proton dissociation –Needs Water
Vassiliki-Alexandra Glezakou, et.al. Phys. Chem. Chem. Phys., 2007, 9, 5752–5760
RSO3H : (H2O)n RSO3-+ H+(H2O)n
Based on these models for the equilibrium:
RSO3H : (H2O)n RSO3-+ H+(H2O)n
When n>3, the ion pair structure, RSO3-+ H+
(H2O)n is more stable than the neutral complex
(H2O)n. Ionization could happen.
• High proton transport rate in PFSA membranes requires a high degree ionization
• At RH <30%, the number of water molecules in a typical PFSA n 3.
• Insufficient water in the membrane can cause a low proton conductivity and poor durability
n=2 n=3
- +
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N2 Cross Over Effect on Parasitic Load
Nitrogen Cross Over
0
1
2
3
4
5
6
7
Target HC Block Co-Polymer
PFSA 1 (~25 um)
No
rma
lize
d t
o T
arg
et
Normalized H2 Pump Power
0%
20%
40%
60%
80%
100%
120%
0 0.2 0.4 0.6 0.8 1
Nitrogen Mole Fraction
% o
f Max
imum
The amount of gas that needs to be pumped back into the stack inlet is proportional to the nitrogen cross over rate.
The power required to pump this nitrogen is waste and requires extra cells to produce it.
The recycle circuit is typically purged to get rid of the accumulated nitrogen which inevitably wastes hydrogen.
Incremental improvements in nitrogen crossover directly benefit the cost and fuel economy of Fuel Cell Vehicles.
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Gas inlet: Ambient atmosphere , T 95 C
0
20
40
60
80
100
120
0 20 40 60 80 100 120
Cost US$/m2 (volum 850k m2 per year)
Mem
bra
ne
per
form
ance
& d
ura
bil
ity
Random HC polymer
Block HC polymer+ reinforcement
LSC PFSA+reinforcement
LSC PFSA
low cost SSC PFSA+reinforcement
SSC PFSA from Supplier C
SSC PFSA from Supplier D
HY5 target
lower cost
imp
rov
e p
erf
orm
na
ce
Cost-Performance Gaps
Gas inlet RH 30%, T 95 C
0
20
40
60
80
100
120
0 20 40 60 80 100 120
Cost US$/m2 (volum 850k m2 per year)
Me
mb
ran
e p
erf
orm
an
ce
& d
ura
bili
ty
Random HC polymer
Block HC polymer+ reinforcement
LSC PFSA+reinforcement
LSC PFSA
low cost SSC PFSA+reinforcement
SSC PFSA from Supplier C
SSC PFSA from Supplier D
HY5 target
lower cost
imp
rove
perf
orm
nac
e
Gas inlet RH 80%, T 85 C
0
20
40
60
80
100
120
0 20 40 60 80 100 120
Cost US$/m2 (volum 850k m2 per year)
Mem
bra
ne
per
form
ance
& d
ura
bil
ity
Random HC polymer
Block HC polymer+ reinforcement
LSC PFSA+reinforcement
LSC PFSA
low cost SSC PFSA+reinforcement
SSC PFSA from Supplier C
SSC PFSA from Supplier D
HY5 target
lower cost
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Bipolar Plates
Driver Plate technology is quite mature due to significant investment by researchers and a competitive environment with the suppliers. Plate assemblies can be made with good quality and strength at thicknesses well below 2mm and it is now the flow field and not plate material that limits further reductions.
Cost - While several suppliers are predicting cost which approach the targets, a significant gap remains with respect to joining/sealing methods, as well as corrosion protection coating technology and production cycle times.
Water Management - At high current densities much higher gas and liquid water fluxes must move through the channels. Water remains a big driver for flow resistance and poor flow distribution.
Technology Area
Driver Size Dura Fuel Econ
Cost Crit Under. Opp Classification
Plate Increased Plate Conductivity 3 1 3 1.8 High Low Technoloy at LimitPlate Precise Plate Mfg Tolerances 1 3 3 1.9 High Low Technoloy at LimitPlate Carbon plate Cycle Time 3 1.2 Med High EngineeringPlate Carbon raw materials Processing 3 1.2 Med Med EngineeringPlate Facile Liquid Water Removal 1 3 9 3 4.6 High Med High Priority ResearchPlate Improved Plate Formability 3 1 3 9 5 High Med High Priority ResearchPlate Increased Plate Strength 3 3 0.9 High Low Technoloy at LimitPlate Metal Coating materials/process 3 9 3.9 Low Med High Priority ResearchPlate Metal or Carbon Joining Method 3 9 4.2 Med Med EngineeringPlate Metal Plate Substrate Alloy 3 3 1.8 High Med EngineeringPlate Minimize Plate Web Thickness 3 3 1.5 High Low Technoloy at LimitPlate Plate Corrosion Resistance ( metal only) 9 3 3 Low Med High Priority Research
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Carbon or Metal: No Clear Winner
Coated Metal
Carbon Composite
• Inherently corrosion resistant.
• Conductive surface.• 200 um web thickness.
• Better FF, seal, and backside geometry possible.
Inherent Advantages
Needed Improvements
• Strength/toughness
• Process cycle time
• Raw material costs
• Low cost joining method
• High Strength/Toughness
• 100 um web thickness
• Inexpensive forming process
• Inexpensive substrate
• Coating Cost/Process
• Welding/joining cost
• Surface contact resistance plate to plate
• Available formed shapes.
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Pressure Drop Vs Water
2
2V
D
LfP Re
64f
22
Re)(
D
VLfP
VD
Re
Effect of Water on Pressure Drop and Apparent Friction Factor
64
74
84
94
104
114
124
134
0 50 100 150 200 250 300 350 400 450 500 550
Reynolds Number Vapour Included (Re)
f*R
e
Dry f*ReWet f*Re ~ 10 to 30 % more liquid waterAdvanced Flow Field #1 Wet Advanced Flow Field #2 Wet
For a smooth wall circular pipe
Gen 4 flow field advancements reduce pressure drop of advanced cells by ~30 %
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Power Density Progress
Stack Power Density and Cell Pitch
0
500
1000
1500
2000
2500
1990 1995 2000 2005 2010 2015
Year
Sta
ck V
olu
met
ric
Po
wer
Den
sity
(kW
/L)
0
1
2
3
4
Cel
l P
itch
(m
m)
Power Density (volumetric) Cell Pitch
Mk5 Mk7 Mk8 Mk901 Generation 1 Generation 2
Current density
Generation 3 Generation 4
Current density and cell pitch
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Conclusions
• There are many open paths to make further progress on Fuel Cell System costs.
• There has been a great deal of progress in many key areas: o Our understanding of the options is good.o There are quite a few mature technologies that can be
exploited in the generation 4 cars.
And thus:o Resources will be focussed onto paths with the most
remaining opportunity and highest impact on cost.
• This focussed research and engineering effort will enable us to meet commercial fuel cell targets
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