SECA Program Review · 2014. 7. 29. · The electrical performance of Siemens cathodeThe electrical...

SECA Program Review

Presented at the 10th Annual SECA WorkshoppPittsburgh, PAJuly 15, 2009

Shailesh D. VoraSiemens EnergyFossil Power Generation Stationary Fuel Cells

Schutzvermerk / Copyright-VermerkCopyright © Siemens Energy Inc. 2009. All Rights Reserved

Significant ResultsSignificant Results

Demonstrated significantly higher power density and higher power per cell relative to cylindrical cells through materials and cell design i timprovements

Demonstrated voltage stability of next generation cells - Delta8

Completed Phase 1 stack testCompleted Phase 1 stack test

Met all Phase 1 milestones

Developed lower cost and scalable processes for cell manufacturingDeveloped lower cost and scalable processes for cell manufacturing

Developed materials and processes to further increase cell power by 50%

Increased Delta8 cell length to 100 cm from 75 cm– new cell active area 2570 cm2

Completed stack design for Phase II stack test

Slide 2 July 2009 E F NT SFC10th Annual SECA WorkshopCopyright © Siemens Energy Inc. 2009. All Rights Reserved

p g

Initiated assembly of Phase II stack

Siemens Tubular GeometrySeal-Less Solid Oxide Fuel CellSeal Less Solid Oxide Fuel Cell

C th d InterconnectionCathode Supported

D = 22 mm

Interconnection

Fuel flow

L = 1500 mm

A = 850 cm2

Electrolyte

Air electrode

T = 1000oC

Fuel electrodeAi fl

Air Flow

Air flow

Air feed tube (AFT)


Siemens Solid Oxide Fuel CellMaterials and ProcessingMaterials and Processing

Component Material Present Fabrication ProcessAir ElectrodeElectrolyteInterconnectionF l El t d

Doped LaMnO3

ZrO2(Sc2O3)Doped LaCrO3

Ni Z O (Y O )

Extrusion-SinteredAtmospheric Plasma SprayingAtmospheric Plasma SprayingAt h i Pl S iFuel Electrode Ni-ZrO2 (Y2O3) Atmospheric Plasma Spraying


Base-line Cell PerformanceBase line Cell Performance

Single Cell PerformanceSingle Cell Performance

DC Power: 110 W/cell @ 0.70 VFuel: HydrogenTemperature: 1000oCTemperature: 1000 CFuel Utilization: 80%

In-System Performance

Net AC Power: 100 W/cellFuel: Reformed natural gasTemperature: 940oC averageNet electrical efficiency: 46% (atmospheric pressure)


Net electrical efficiency: 46% (atmospheric pressure)

Cell Voltage StabilityCell Voltage Stability

1.10

0.80

0.90

1.00

sity

(A/c

m2 )

Temperature: 1000 C Fuel Utilization: 85%

Changed Test Stand

0.50

0.60

0.70

V), C

urre

nt D

ens

Cell Voltage (V)Changed Test Stand

0.20

0.30

0.40

Cel

l Vol

tage

(V

Current Density (A/cm2)

0.00

0.10

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000

Test Duration (Hours)


∼ 0.1% per 1000 hours voltage degradation

Transition from Tubular to High Power Density (HPD) Cell

Interconnection

Electrolyte

Interconnection

ElectrolyteInterconnectionInterconnection

a s t o o ubu a to g o e e s ty ( ) Ce

Air Electrode

Electrolyte

Air Electrode

Electrolyte

Fuel ElectrodeAir Flow Fuel Electrode

Air ElectrodeElectrolyte

Fuel Electrode

Air Flow Air Electrode

ElectrolyteFuel Electrode

Air Flow

Air Flow

Tubular HPD

Closed end enables seal-less design

Red ction in ohmic resistance

Advantages

Reduction in ohmic resistance

Increase in cell power density

More compact stack


Same cell materials and manufacturing processes – Different design

First Generation HPD Cellsst Ge e at o Ce s

Active Length: 75 cmg

Active area: ~900 cm2


Developed HPD5 (five channels) and demonstrated benefits relative to tubular cells

HPD Voltage StabilityHPD Voltage Stability

0.90

1.00

1.10

m2 )

Average Temperature: 900ºCFuel Utilization: 80%Fuel: Humidified Hydrogen

UpgradedTesting

Instrumentation

Cooled for Stand Maintenance and

Calibration

0 50

0.60

0.70

0.80

ent D

ensi

ty (A

/cm

Cell Voltage (V)

0.20

0.30

0.40

0.50

Volta

ge (V

), C

urre


0.00

0.10

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000 18,000 20,000 22,000 24,000 26,000 28,000 30,000


Cel

l V



Accomplishments and Next StepsAccomplishments and Next Steps

Demonstrated thermal cyclic stability - can withstand multiple y y pthermal cycles

Demonstrated voltage stability - voltage decline of ∼ 0.1% /1000 h

Cost reduction measures in progress

– Increase cell power density

– Lower parts count

– Reduce assembly cost

– Simplify balance-of-plant


Next Generation Cell Concept – Delta8…Next Generation Cell Concept Delta8…

Closed end - maintains seal-less design Shorter current path - reduction in ohmic resistance Increase cell power densityIncrease volumetric power density of stackIncrease cell active area (higher power per cell)


…leading to cost reduction in the cell area

Delta8 Cell Performance –Voltage vs. Current DensityVoltage vs. Current Density

0.78

0.79

0.80

0.25

0.30

Power Density

Tavg = 975 ºCFuel Utilization = 80%Fuel = Humidified Hydrogen

0.75

0.76

0.77

age

(V)

0.15

0.20

sity

(Wat

ts/c

m2 )

yFuel = Humidified HydrogenCell Length = 75 cmCell Width = 15 cmCell Area = 1950 cm2

0 72

0.73

0.74 Vol

ta

0.10

Pow

er D

ensVoltage

10% higher power density compared to last year through processing improvements

0.70

0.71

0.72

150 175 200 225 250 275 300 325 350 3750.00

0.05year through processing improvements

550 watts per cell @ 0.7 V (extrapolated)


Current Density (mA/cm2)

Cell Performance ComparisonCell Performance Comparison

2250

2500

CylindricalDelta8

1950

1750

2000

(Wat

ts)

e a8T = 1000 C

Fuel Utilization = 80% Fuel = Hydrogen Cell Voltage = 0.7 V

1000

1250

1500

(cm

2 ) Cel

l Pow

er

850

550500

750

1000

Cel

l Are

a (

110

0

250

Cell Area Cell Power


Delta8 cell area increased by ∼ 2X vs. cylindrical cell… cell power increased by ~ 5X

Delta8 Cell Voltage Stability (2-cell test)Delta8 Cell Voltage Stability (2 cell test)

2.20

1.60

1.80

2.00

2.20

(A/c

m2 )

Average Temperature = 950ºCFuel Utilization = 80 %Fuel = Humidified Hydrogen

1.00

1.20

1.40

Cur

rent

Des

nity

(

Voltage (V)

0 20

0.40

0.60

0.80

Volta

ge (V

), C


0.00

0.20

0 125 250 375 500 625 750 875 1000 1125 1250 1375 1500 1625 1750 1875 2000



Excellent voltage stability

Cell and Bundle ComparisonCell and Bundle Comparison

24 cylindrical cellsT = 1000 CFuel Utilization = 80%F l H d

DC power: 2.6 kWeWeight: 34 kg

550 W1950 cm2

CylindricalDelta8

Fuel = HydrogenCell Voltage = 0.7 V

2x2x

850 cm2

5x5x

6 Delta8 cellsDC power: 3.3 kWeWeight: 20 kg

110 W

Reduced weight by 40%, increased power by 25%

Area Power


Phase I Stack TestPhase I Stack Test

24 Delta8 cells (75 cm long)

4 bundles (six cells each)

Internal recuperator

Cast ceramic open end holder

Operation on simulated coal gas

Thermally self sustaining

Modified existing balance of plant for stack test


Phase I Integrated SystemPhase I Integrated System

Cell Stack Complete System


Cell Stack Complete System

Phase I Stack Test ResultsPhase I Stack Test Results

Phase I Minimum Requirements

Siemens System Test

ResultsResults

DELIVERABLE POWER RATING ≥ 10 kW 10 kW

5000 hours 5300 hours STEADY STATE TEST (Normal Operating Conditions) Δ Power < 4.0% degradation/1000 hours No detectable degradation

1) Start up and conditioning

TEST SEQUENCE

1) Start-up and conditioning2) Peak Power Test (after ~300 hours) 3) VJ curve 3) Steady State Test (balance of 5000 hours) 4) Shut-down

In accordance with DOE approved Test Plan

FUEL TYPE Simulated (subject to DOE concurrence, up to 25% CH4, dry basis)

Hydrogen and simulated coal gas

Availability factor of 85% at


AVAILABILITY Report availability 50% power or greater

Cell Development . . .Cell Development . . .

Cell Fabrication

– Seamless closed end

– One-Step sintering of cathode

Mass production concepts for plasma spray– Mass production concepts for plasma spray

Cell Power Enhancement

. . . Results in cost reduction, scale-up and manufacturability


Present Process To Attach Closed EndPresent Process To Attach Closed End

Closed end cap is attached to the cell in the green stage and the assembly is sintered


Seamless Closed EndSeamless Closed End


Closed end cap is extruded with the cell … resulting in reduced labor

Horizontal (One-Step) Sintering of CathodeHorizontal (One Step) Sintering of Cathode

Old process – Two- step sintering– Horizontal sintering (∼ 1200 ºC) followed by vertical sintering at ∼1500 ºC

New process– Developed non-reactive substrate to sinter cathodes in one step up to ∼1500 ºC


… resulting in reduced labor, uniform porosity, and uniform dimensions

Plasma Spraying

Present Process

Plasma Spraying

Single part per event

One gun system

Each surface is individuallyEach surface is individually coated

Significant part handling

Not scale-up friendly


Plasma SprayingConcept for Mass Production

Manufacturing Carousel Design

Concept for Mass Production

Multiple cells processed in one event

Plasma guns travel verticallyPlasma guns travel vertically while carousel rotates

Multiple plasma guns

R b t t di i l tRobust to dimensional part variation

All surfaces coated i lt lsimultaneously

Significant reduction in spray time


Cell Power EnhancementCell Power Enhancement

The electrical performance of Siemens cathodeThe electrical performance of Siemens cathode supported cells is primarily influenced by the cathode–electrolyte interface due to high polarization

cathode+EL21.0%

950oC

Ohmic33.6%cathode-p

58.1%

anode-p7.5%

anode10.3% IC

3.2%


Cell Power EnhancementCell Power Enhancement

Lowered electrolyte densification temperature by ∼300 ºCLowered electrolyte densification temperature by ∼300 C through materials and processing improvements

Maintain active cathode layer porosity– Maintain active cathode layer porosity– Prevent formation of insulating phases at the cathode-

electrolyte interface

Reduced electrolyte thickness by 50%

Materials and process development work done on cylindrical cells

Readily transferrable to Delta8 cells


Readily transferrable to Delta8 cells

Electrolyte MicrostructuresElectrolyte Microstructures

Anode

80umElectrolyte

Present electrolyte

Cathode

½ Thickness electrolyte

20um

¼ Thickness electrolyte

40um


Cell Performance – Cylindrical CellsCell Performance Cylindrical Cells

0.850

0.750

0.775

0.800

0.825

0.850

New cell materials and

0 625

0.650

0.675

0.700

0.725

Vol

tage

(V)

materials and processing

50%

0.525

0.550

0.575

0.600

0.625

Present cell materials and processing

Temperature = 900 CFuel Utilization = 80%Fuel = Humidified hydrogen

0.50050 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450 475

Current Density (mA/cm2)


50% higher power density at 0.70 V

Voltage Stability of Power Enhanced Cylindrical CellVoltage Stability of Power Enhanced Cylindrical Cell

1.1 1100

0.7

0.8

0.9

1.0

Vol

tage

(V)

700

800

900

1000

°C)

Cell Voltage

0.4

0.5

0.6

0.7

Dens

ity (A

/cm

2 ) -

V

400

500

600

700

Tem

pera

ture

(°Cell Voltage

Current DensityC.E. TemperatureMid Temperature

0.0

0.1

0.2

0.3

Cur

rent

0

100

200

300

0 500 1000 1500 2000 2500 3000 3500


0

Excellent Voltage Stability …

………. Test Continues


Excellent Voltage Stability … Next step: Adapt Process and Materials to Delta8 cells

Delta8 Cells – Increased Cell Length and AreaDelta8 Cells Increased Cell Length and Area

1 M active length cell L = 100 cmW = 15 cm

This Year

A = 2570 cm2

L = 75 cmW = 15 cm

Last Year

W = 15 cmA = 1950 cm2


1 M active length cell selected for Phase II stack test

1x8 Delta8 Bundle (1 M active length cells)1x8 Delta8 Bundle (1 M active length cells)


Performance Projection - 1 M Delta8 Cells and BundlesPerformance Projection 1 M Delta8 Cells and Bundles

725 W

CylindricalDelta8

Temperature: 1,000 ºCFuel Utilization: 80%Fuel: Humidified HydrogenCell Voltage: 0.70 V *

6.5x6.5x2570 cm2

850 cm2

3x3x6.5x6.5x

110 W

Area Power

* Projection based on data for 75

Delta8 area increased by ∼3X vs. cylindrical, however power increased by ∼6.5X

24 cylindrical cellsDC power: 2.6 kWeWeight: 34 kg

8 Delta8 cellsDC power: 5.8 kWe*Weight: 32 kg

Area Powerdata o 5cm active length cells


Reduced weight by 5% and increased power by 120%, resulting in lower cost and smaller footprint

Basic Building Block for Larger UnitsBasic Building Block for Larger Units

Eight 1 M Delta8 cells

Fully integrated bundle assembly contains fuel plenum, cell bundle, open end seal, recuperator, exhaust plenum, intake air plenum and electrical connectors

Cast ceramic components

Provides fuel, air, exhaust and electrical interfaces for the fuel cells

Compact recuperator preheats incoming air and eliminates external hot pipingCompact recuperator preheats incoming air and eliminates external hot piping

Six basic building blocks will be tested in Phase II stack test


Phase II StackPhase II Stack

Recirc PlenumStack Liner

Recirc PlenumGuard Heaters

Dielectric Boards

DielectricDielectric Boards

Cell Bundles


Delta8 Cell Module - Power System Building BlockDelta8 Cell Module Power System Building Block

480 Delta8 cells

Natural gas fuel

Nominal Power ~ 250 kW (atm. pressure)(atm. pressure)

Module Dimensions:

Height – 3.4 m

Exhaust

Width – 3.7 m

Depth – 1.9 mAirAir


Larger fuel cell power systems are effectively assembled by aggregating modules

SummarySummary

Met all Phase I milestones

E t bli h d D lt 8 ll i t d f b i t d b th 75 dEstablished Delta8 cell processing parameters and fabricated both 75 cm and 100 cm active length cells and bundles with these cells

Demonstrated seamless closed end extrusion for Delta8 cells

Showed significant progress in developing mass production concept of plasma spray process

Improved power density of Delta8 cells by approximately 10% over first generation cellsgeneration cells

Demonstrated voltage stability of Delta8 cells

Showed 50% power enhancement in tubular cells by lowering the electrolyte d ifi ti t t d d i th l t l t thi k i h lfdensification temperature and reducing the electrolyte thickness in half –Reduction of electrolyte thickness to ¼ of present value is feasible

Completed design of Phase II stack test


Initiated assembly of Phase II stack test

AcknowledgementsAcknowledgements

DOE NETL C t t N DE FC26 05NT42613DOE-NETL. Contact No.DE-FC26-05NT42613

Wayne Surdoval, Travis Shultz, Heather Quedenfeld - NETL

Siemens Stationary Fuel Cells TeamSiemens Stationary Fuel Cells Team


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