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©2016 LG Fuel Cell Systems Inc.

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LG Fuel Cell Systems Program and Technology Update

DOE 17th Annual SOFC Review, 19 July 2016

Shung Ik Lee and Adam Babcock


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Contracts

Work performed by LG Fuel Cell

Systems under DOE contracts:

DE-FE0012077: SECA Coal-Based

Systems LGFCS

DE-FE0023337:Improved Reliability of

SOFC Systems

DE-FE0026098: Advanced Materials and

Manufacturing

2

•LG data – Commercial in Confidence; Proprietary; US

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Outline

Performance Improvement

Cost Reduction

Durability

Block Testing

Advanced Materials and Manufacturing

Summary

3


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Outline

Performance Improvement

Fuel cell system operation strategy

ASR improvement for longer service life

and cost reduction

Cost reduction

Durability

Block Testing


LGFCS Program

4


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Plant Operation Options Based on Stack Performance

Initial ASR and ASR degradation rate are key metrics for benchmarking cell technology

System design must be able to operate over a wide range of ASR (starting to end-of-life) while maintaining specified stack temperature range

Operation based on current technology developed to date

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Time, Years

Plant Operation Options - Constant Power/Heat Release

ASR = 0.28 ohm-cm2

Power Rating →

← DC Efficiency

440 to 485 mA/cm2 current density


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EIS Tech. provide ASR benefit (0.04~0.05 Ω) compared with

IST Tech.

ASR Reduction Achievements

•* Manufacturing QA data

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Additional ASR Reduction Achieved using Nickelate Cathodes

Candidate nickelate cathodes have ~0.02 Ohm cm2 lower cell ASR

at 860C, 4bar

7

•4bar


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Current Status for Nickelates Difficult to achieve complete phase stability

But, still promising durability even with multiple

phases present

Recent further improvements in degree of phase

instability

8

•Nickelate composite II (PCT238 A2) Elapsed time : 7200hr

•Nickelate composite I (PCT222 B1) Elapsed time : 9500hr

~6 mohm-cm2/1000hr

•New Composite, 870C 500hrs


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Outline

Performance improvement

Cost reduction

Cell and stack design changes

Current density

System simplification for cost reduction

Durability

Block Testing


LGFCS Program

9


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Cell & Tube Design Options for ASR Reduction & Power Increase

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Smaller PIC dimension has

lower ASR contribution

Power increased using

longer tube (~100W/tube)

•P-Value=0.001

PIC ASR reduction: 0.012 Ohm cm2 (PCT)

Baseline

66Cells

82Cells longer tube


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In-Block Reforming Enables Higher Power Density

In Block Reforming reduces stack DT to allow higher power density for the

same air flow

Single tube mapping tests showed no evidence of performance loss with

various levels of IBR

Low ASR enables higher current density while maintaining efficiency

P = 19 kW

DT = 80 °C

IST configuration

P = 25 kW

DT = 80 °C

IBR configuration

Cell performance

•75% IBR

DNG + Recycle

DNG + Recycle

Partially Reformed

Increasing % IBR

No change in anode peak

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Anode Protection System Simplification for Cost Reduction

Operational scheme results in anode redox

A minimal number of redox cycles required for product

cost reduction by 75% from early design of Anode Protection Unit

•Early system designs utilized a

separate subsystem for system

scale APG generation

• Pellet Redox

• Exposure to air for 2 hrs at 900C

• 5 cycles

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Outline


Cost reduction

Durability

Cathode

Anode

PIC

Degradation rate

Block Testing


LGFCS Program

13


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MnOx Accumulation, Redistribution Status of Understanding, Solutions

Mn enrichment greater at low

temperature

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temperature

15

MnOx source appears to be from

throughout the cathode and CCC

layers. No significant localized

LSM stochiometry change

Even 5% A-site deficient CCC

has free-MnOx as-fabricated.


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temperature

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Localized at interface (driving

force?)

Overpotential and/or pO2


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temperature

17







Localized at interface (driving

force?)

Overpotential and/or pO2

Mn valence along interface

Using EELS

As fired

900C

800


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Cathode Densification – Status of Understanding, Solutions

Densification greater at high

temperature

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temperature

Densification is greatest under

localized low pO2 if kinetics are

high

Pressurized SOFC benefit higher

pO2

19

Degree of A-site deficiency

influences densification


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temperature



high


pO2

20



B-site dopant selection can

reduce densification

(B site doping)

Acceleration test 1000hr


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8um CA

7um DL 8um CA 15um CA



temperature



high


pO2

21



B-site dopant selection can

reduce densification

Densification increases Rp


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Anode Degradation– Status of Understanding, Solutions

Bilayer anode+ACC versus single

layer

Avoidance of interfaces

resistance

22

925C, 4000hr

925oC 5000hr


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925C, high steam ,4000Hr



layer


resistance

23

Ni accumulation along interface

at high temp and higher Uf


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layer


resistance

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Loss of TPB

Redox event


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layer


resistance

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Loss of TPB

Anode-side conductivity

retention important for durability


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layer


resistance

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Loss of TPB

Anode-side conductivity

retention important for durability

Mn penetration through

Electrolyte was not observed

thus far (16000hrs)

925C, 4000hr

925oC 5000hr

925C, high steam ,4000Hr


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Primary Interconnect Degradation– Status of Understanding, Solutions

Anode-side barrier layers

were applied to primary

interconnect region to

improve durability

Cathode side barrier layers

further improving interface

quality

Lower initial ASR

Improved long term

durability

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Durability Trends: 3-10 mohm-cm2/1000 hrs

New cathode bundle test (ATBT6) at 1 bar demonstrated < 7

mohm-cm2/1k hrs over 2 year test

Subscale cells (PCT189) demonstrated < 3mohm-cm2/1k hrs

over 2 year test

Correspond to 0.10~0.15%/1000hr power degradation rate

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Plant Life Improved with Lower ASR and Degradation Rate

Reduction of degradation rate from 8 to 5 mohm-cm2/1k hrs with ASR of

0.24 ohm-cm2 permits nearly constant power operation over 5 year life

ASR reduction using lower cathode Rp + Shorter PIC + thin wall substrates

> 0.04 Ohm cm2

Average efficiency also significantly higher

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Time, Years

Plant Operation Options - Constant Power/Heat Release

ASR = 0.28 ohm-cm2

ASR = 0.24 ohm-cm2, Lower Degradation

Power Rating →

← DC Efficiency

440 to 485 mA/cm2 current density


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Outline


Cost reduction

Durability

Block Testing

Block Test T1418 & T1315

IBR Block Test T1506


LGFCS Program

30


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Block Testing Matching Product Cycle, Components and Operating Conditions

Turbo-Generator

Fuel Cell

Cathode

Fuel

Cell

Anode

OGB

Anode Ejector

Cathode Ejector

Turbo-Generator

RRFCS NG “Dry Cycle” Configuration

Auxiliary

Ejector

R

E

F

O

R

M

E

R

R

E

F

O

R

M

E

R

Auxiliary

Heat Exchanger

Heat Source for Cathode Loop;

Partially-Spent Anode Gas,

Heated Cathode Loop Air,

and Hot Recycle

De-Sulfurized

NG

Recuperator

Initial design of block testing rigs

Representative of cycle and components

Not packaged for product (T13xx, T14xx) Integrated block

Design for product

(T1506)


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T1418: First Block Test of EIS Technology

Test Identification Strip 1 – EIS1 cathode &

lower ASR interconnect

Strips 2-4 IST (Epsilon)

standard strips

Test Objectives Test 5000 hours with

power degradation

< 0.75%/1000 hrs

Results 1.30% Power Degradation/1khrs

0.30 ohm-cm2 ASR at 1500 hours

was as expected

Average DC Efficiency ~ 62%

Completed 1450 hours on load

Test run short due to BOP issues

Decision to convert rig to IB standard

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T1418 (SOFC76) - Power and DC Efficiency

Total Power

Efficiency

30-Mar-16 10:26:51

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T1315: EIS Cathode Screening Block Test

Test Objective Test 2000 hours with power

degradation < 1.5%/1000 hrs

Results 0.78% Power Degradation/1khrs

Average DC Efficiency ~ 60%

Completed 2049 hours on load

Test Identification 4 different cathode configurations

Standard IST (epsilon)

3 EIS candidates

Lower ASR interconnect

IST (Epsilon) standard anode

EIS

1E

IS2

EIS

1E

IS2

EIS

1e

EIS

3E

IS2

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Time at Temperature, hours

T1315 (Block 3 in SOFC73) - Block Power

Total Power

DC Electrical Efficiency

18-Apr-16 13:20:00

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T1506: Demonstration of In-Block Reforming

• Initial power 25.6 kW

• Highest single block power

• Test duration 511 hours on load

• Lowest block ASR tested

• Achieved <80°C dT

• Strip Technology

• EIS1 Cathode

• Lower ASR interconnect

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T1506 - IBR Block Test - Average Block ASR and Temperature

From Overall Current/Voltage

Cathode Average Temperature

Total Power = 25.14 KW

01-Jul-16 04:10:31

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Time on Test, hours

T1506 - IBR Block Test - Block Power and Anode Loop Efficiency

01-Jul-16 04:10:31

Total Power = 25.14 KW

Time on load = 510.8 hrs

True value of ASR 0.27-0.28, ~0.023 higher

than calculated value - owing to calculation

assumption of linear variation of Nernst voltage

from inlet to outlet

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0.00

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0 500 1000 1500 2000 2500

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R o

hm

-cm

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Time, hours

Comparative ASRs

T1314

T1315

T1418

PBT20

T1506

IBR Block Performance: Within Range of Sub-scale Tests

• Improved block ASR from

T1314 to T1315/T1418

• Excellent correlation from

bundle PBT20 to block

T1506

• ASR degradation rates

tend to converge after

longer test periods

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T1314

T1315

T1418

PBT20

T1506

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Block Performance Summary 36

Parameter T1314 T1418 T1315 T1506

Initial Power (Normalized for 5 strips)

18.8 kW 19.5 kW 19.7 kW 25.6 kW

Starting ASR (ohm-cm2)

0.35 0.28 0.28 0.27Note 1

Current Density (mA/cm2) 380 380 380 530

Fuel (@ 75 – 80% Uf) Bottled CH4 PNG Bottled CH4 PNG

Power Degradation (per 1000hrs) 1.2% 1.3% 0.78% Note 2

Duration (hours) 3040 1450 2049 520Note 3

Cell Technology Pre-Eps Eps, EIS EIS EIS + IBR

Note 1: Accounting for non-linear Nernst voltage

Note 2: Power Degradation rate given once test accumulates >1000hrs of test time

Note 3: Still under test


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Outline


Cost reduction

Durability

Block Testing


Task 2.0

Task 3.0

LGFCS Program

37


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Task 2.0: Identify Candidate Components Cathode and Anode Ejectors

Cathode and Anode Pipework

Task 3.1: Identify Materials Anode Ejector (low temp.) - continue using SS

310/316

Auxiliary Ejector (high temperature) materials considered H120, RA330, AFA25, 601, and 230

Task 3.2 Identify Processes

38

• additive manufacturing (AM) • spin forming

• metal injection molding (MIM) • lost wax casting

• hot isostatic pressing (HIP) • other processes


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Advanced Materials Project Status Summary

Key Findings Five candidate alloys identified based on material

requirements

Preliminary cost study suggests ~50% reduction for aux. ejector

Metal Injection Molded (MIM) coupling fitting cost ~$8 & $9 at 50 MW quantities

Estimated 77% - 89% cost reduction vs low-volume machined component

Lessons Learned Additive Manufacturing Process is only cost effective for

the complex nozzle assembly

Other manufacturing processes are being explored spin forming

lost wax casting

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Summary

Significant progress made regarding performance improvements and durability. There is a better understanding on how to increase the life of the LGFCS fuel cell. These improvements will have a direct impact on reducing costs.

Block testing, though challenging, has shown that ASR tracks across multiple scales. Improvements in cell technology and system performance allowed for LGFCS’s best block test to date.

The advanced materials and manufacturing project continues to support material selection and cost reduction of critical components.

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Acknowledgements

Special thanks to LGFCS project managers Patcharin Burke, Shailesh Vora, and the entire SOFC program management team

This material is based upon work supported by the U.S. Department of Energy, National Energy Technology Laboratory under Award Number DE-FE0012077, DE-FE0023337, and DE-FE0026098

Disclaimer: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of the authors expressed herein do not necessarily state or reflect those of the United States Government of any agency thereof.

41

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