Development Update on Delphi’s Solid Oxide Fuel Cell Power System
Steven ShafferChief Engineer – Fuel Cell Development
Philadelphia, PA2006 SECA Review Meeting
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Acknowledgements
Fuel Cell Development Team
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Outline
• Market Opportunities• Systems Development• Cell and Stack Development• Reformer Development• Cost Analysis• Summary
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derivatives
US Stationary – APU & CHPNatural Gas, LPG
European micro –CHP& CHCP
Natural Gas
Commercial PowerNatural Gas
SOFC Market Opportunities
FutureGen PowerplantCoal Gas
Recreational VehiclesDiesel, LPG
US MilitaryJP-8
Heavy Duty TruckDiesel
Truck and Trailer Refrigeration
Diesel
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Development Strategy
Core Fuel Cell
System Technologies“Building Blocks”
Stationary Power
AutomotiveCommercial
Vehicle
Mobile Power
Marine
Military
- SOFC Stack- Heat Exchangers
- Process Air- Controls
Each application adjusted for:- Fuel Type- Electrical Configuration- Application Environment- User Interface
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Outline
• Market Opportunities• Systems Development• Cell and Stack Development• Reformer Development• Cost Analysis• Summary
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SECA Phase I Starting Point
2002Gen 2A (Level 0)0.270 kWgross
SOFC Hot-Zone Module
Control Cabinet
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Delphi Systems Developed During Phase I
2003
Gen 2A0.220 kWgross
2004
Gen 2B/2C0.423 kW, 3.3% efficiency
2005
SPU 1A1.18 kW, 17% efficiency
2006
SPU 1B2.16 kW, 38% efficiencyPhase I Progress
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SOFC System Mechanization
BASIC CPOX REFORMING MODEHIGH EFFICIENCY
INTERNAL REFORMING MODE
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Integration of SPU 1B SOFC System
DC POWER OUTPUT
DESULFURIZED FUEL INPUT
SIGNAL I/O
HOT EXHAUST
AIR INLET
THERMALINSULATION
HOT ZONE MODULE
PLANT SUPPORT MODULE
APPLICATION INTERFACE
MODULE
PROCESS AIR
MODULE
2x30-cell SOFC STACKS
CATHODE AIRHEAT EXCHANGER
CPOX NATURAL GAS REFORMER
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SPU 1B SOFC System
2x30-cell SOFC StacksCathode Air Heat
ExchangerRecycle Cooler
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SECA Phase I Test Plan
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Delphi Phase I Demo System A Test
Delphi SPU 1B Unit
Set 2 SOFC System on Test
Set 3 SOFC System on Test
Exhaust ScrubberDAQ Cabinet
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Delphi Phase I System Performance
System Metrics Target Set 2 Set 3 2 & 3 Combined
Rated Net Power 3 kW 2.08 2.16 4.24
System Efficiency (Peak) 35% 35.1% 38.9% 37.0%
Factory Cost $800/kW $767
Durability Test 1500 hours 4660 2240 >1500
Temp Cycles 1 cycle 2 2 1
Power Cycles 9 cycles 10 10 10
Net Power Degradation7% / 1500
hours 4.5% 10.1% 7.3%
Operational Availability 80% 99% 99% 99%
Delphi System Performance
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Delphi Phase I Durability PerformanceDemonstration System
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Test Time (hours)
Pow
er, k
W
Total Net Power (kW)
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le
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hut D
own
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hut D
own
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Self-
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Delphi Phase I Durability PerformanceSPU 1B – Set 2
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-500 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
Test Time (hours)
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er, k
W
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Ther
mal
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le
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mal
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le
Stac
ks R
etire
d
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Delphi Team SECA Phase I SuccessSECA Phase I Goals Delphi Demonstration Unit
Power 3 to 10 kW 4.24 kW
Cost < $800/kW $767/kW
Efficiency 35 – 55% 37% LHV- DC
Degradation <7%/1500 hours 7.3%/1500 hours
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Delphi SOFC Power System Operation at NETL
Delphi SOFC Power System
Laboratory Test Platform
Delphi SOFC Power System operated at NETL Test Facility in Morgantown, WV from May 2, 2006 through June 17, 2006
Testing conducted at Normal Operating Condition of 1.0 kW, average net electrical output
610 hours of operation using methane
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Outline
• Market Opportunities• Systems Development• Cell and Stack Development• Reformer Development• Cost Analysis• Summary
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Anode Supported Cell MicrostructureDelphi is fabricating anode supported cells with LSCF cathodeCurrent footprint is 140mm x 98mm (active area 105 sq cm)Currently producing ~80 cells per week A typical microstructure is shown below
Cathode: LSCF (~30 µm)
Interlayer: Ceria Based Layer (~4 µm)
Electrolyte: 8 mol. YSZ (~10 µm)
Active Anode: NiO – YSZ (~10 µm)
Bulk Anode: NiO – YSZ (~500 µm)
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Cell Process DevelopmentKey process development for cells have included:
– Improved tape characterization, improvement of lamination parameters– Electrolyte processing optimization (solids loading optimized)– Bi-layer sintering operation development using Design for Six Sigma (DFSS) - significantly
increased yields
Key focus on developing specification for materials, tapes and inks for high volume manufacturing –includes identifying and developing relationship with high volume manufacturing suppliersDelphi is also exploring viability of manufacturing cells with larger footprints for application in large power plants for stationary markets
Bilayer Yields
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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
Batch #s (2005, 2006)
Yiel
ds (%
)
Yield Improvement due to DFSS based
process development
Problem traced to heating element failure
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Long Term Stability of Cell Materials
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0 200 400 600 800 1000 1200 1400 1600
Time (h)
Spec
ific
Pow
er (m
W/c
m2 )
Button cell tests ongoing for materials developmentStable performance from LSCF cathode based cell demonstratedNo degradation in 1500 hours after initial stabilization
No degradation
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Coating Development for Interconnects
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0 20 40 60 80 100 120 140 160 180 200
Time (h)
% P
ower
Ret
entio
n
* 100 - 200 hrs (or after 100 hrs)** power retention was normalized to the power @ 10 hrs
Baseline (750°C, 0.7V)
with low cost conductive coating (750°C, 0.7V)
with uncoated Crofer
Low cost coating being developed for Cr retention – data shown below on a button cell test with Crofer 22 sample (coated and uncoated) in the cathode environment
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Effect of 1.0 ppm H2S on Standard Cell
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0 50 100 150 200 250
Time (h)
% P
ower
Ret
entio
n (P
Dt/P
D10
0hrs
)
H 2 S free Baseline (750°C, 0.7V)
1.0 ppm H 2 S (750°C, 0.7V)
Development ongoing to understand and minimize degradation mechanisms due to H2SData below shows lowering in power due to addition of 1ppm H2S in hydrogen at 750oC
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Generation 3.1 30-Cell Stack
Generation 3.1 30-cell stack (2.5 liters, 9 Kg)
30-cell modules are the building blocks for Delphi’s power systemsThese 30-cell modules were integrated into the system and operated to meet SECA Phase 1 targets
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Generation 3.1 30-Cell Stack DataPower
– Data below shows a 30-cell Generation 3.1 stack tested in the stack laboratory (furnace, no insulation)
– Produced max power of 2.62 kW (833 mW/cm2) @ 22.6 Volts with 48.5% H2, 3% H2O, rest N2 (53 % utilization, measured anode outlet temperature: 800oC)
» Current development ongoing to map cell temperature and optimize conditions for adequate internal cooling of stack for high power operation in systems
– Fuel utilization studies show a 30-cell stack producing 522 mW/cm2 @ 75% utilization @ 0.8 V per cell, power density of 470 mW/cm2 @ 85% utilization @ 0.8 V per cell
0
5
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0 20 40 60 80 100 120 140Stack Current (Amperes)
Stac
k Vo
ltage
(Vol
ts)
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Pow
er D
ensi
ty (m
W/c
m^2
)
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55 60 65 70 75 80 85 90
Fuel Utilization (%)
Pow
er D
ensi
ty @
con
stan
t cur
rent
75% utilization522 mW/cm2
85% utilization470 mW/cm2
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55 60 65 70 75 80 85 90
Fuel Utilization (%)
Pow
er D
ensi
ty @
con
stan
t cur
rent
75% utilization522 mW/cm2
85% utilization470 mW/cm2
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Cassette Variation in a 30-Cell StackConsistent performance between cassettes in a 30-cell stack (@ 60 Amps, 48.5% H2, 3% H2O, rest N2)
– Voltage difference between best and worst cassette is 0.07Volts
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Cassette Number
Volta
ge (V
olts
)
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Post-Mortem Analysis of StacksFocus is on understanding degradation and failure mechanisms from autopsy of stacks after long term operation in the systemKey lessons learned on seals, interconnects and cell durability Picture below shows an optical micrograph of center slice of 30-cell stack prior to SEM examination.
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Outline
• Market Opportunities• Systems Development• Cell and Stack Development• Reformer Development• Cost Analysis• Summary
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Fuel Reformer Development
Delphi is developing reforming technology for Natural Gas, Gasoline and Diesel/JP-8 for SOFC applicationsTwo main designs are being developed:
– CPOx Reformer» Moderate efficiency» Simplicity of design» Not recycle capable
– Recycle Based (Endothermic) Reformer
» High efficiency » Use of water in anode tailgas
to accommodate steam reforming
» Recycle capable
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CPOx Fuel Reformer Durability on Systems Test –Reformate Composition
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6 500 1501 9 508 1516
set 2 set 3
Time on Test [hrs] by Set
Prod
uct S
peci
es C
once
ntra
tion
[mol
%]
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Average of H2Average of COAverage of CH4Average of H2OAverage of CO2
Plot x
Set Time on Test
Data
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Tubular Endothermic Fuel Reformer
Reformate Out
Anode Tailgas Fuel
Cathode Tailgas Air
Recycle
Fuel
Ref A
ir
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Outline
• Market Opportunities• Systems Development• Cell and Stack Development• Reformer Development• Cost Analysis• Summary
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Delphi Factory Cost Analysis
Establish a standard Bill of MaterialPerform Component Review Meetings (These meetings identify the differences between prototype and production intent designs)Identify and Document Assumptions and JustificationsSubmit Quote Request Forms through Delphi’s Supply Management Team for all purchased componentsEstimates were developed for all manufactured and assembled parts using Delphi’s extensive manufacturing experienceCost analysis audited by outside consultantAudited Phase I Cost Analysis submitted to SECA
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Stack, 39%
Balance of Plant, 33%
System Integration, 15%
Electronics and Controls, 8%
Fuel Reformer, 5%
Cost Breakdown by Subsystem
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Outline
• Market Opportunities• Systems Development• Cell and Stack Development• Reformer Development• Cost Analysis• Summary
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Next Steps:
SECA Phase II:– Conversion to Line Natural Gas with Fuel Desulfurizer– System integration of output power electronics including
A/C inverter– Aggressive cost reduction and manufacturability
improvement– Continued improvement in power, efficiency, and
reliability– Diesel-fueled APU System Development– Improve thermal cycle capability of Stack and System– Meet Phase II targets
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SECA Phase II System Target Metrics