SOFC Power Systems M.J. Day, Principal Investigator 12 th Annual - PowerPoint PPT Presentation

12 th Annual SECA Workshop: July 28, 2011 Invent, Develop, Deliver. Validation of Novel Planar Cell Design for Megawatt-Scale SOFC Power Systems M.J. Day, Principal Investigator 12 th Annual SECA Workshop Pittsburgh, PA July 28, 2011

12 th Annual SECA Workshop: July 28, 2011 NexTech News Invent, Develop, Deliver. Achieved ISO 9001:2008 certification for all  products and processes within NexTech Launched hydrogen safety sensor product(s), and  recently passed UL/ATEX certification tests Launched interconnect coating product  Continued progress made on SOFC stack  technology development

12 th Annual SECA Workshop: July 28, 2011 Outline Invent, Develop, Deliver. Project Details, Objectives, Conclusions  Introduction to FlexCell  Status of NexTech’s SOFC Stack Technology  Results of SECA Project  Future Work 

12 th Annual SECA Workshop: July 28, 2011 Invent, Develop, Deliver. Project Details, Objectives, and Conclusions

12 th Annual SECA Workshop: July 28, 2011 Project Details Invent, Develop, Deliver. U.S. Department of Energy (SECA) DOE Contract Number: DE-NT0004113  Project Monitor: Briggs White  Phase I: 1-Oct-08 to 31-Mar-10  Phase II: 1-Apr-10 to 30-Sep-11  State of Ohio (Third Frontier Program) Cell Manufacturing for 100+ kW SOFC Power Generation Systems  ODOD Contract Number: TECH 08-057  NexTech’s Team Principal Investigator: Mick Day  NexTech Contributors: Scott Swartz, Lora Thrun, Kellie Chenault  Subcontractor: Ohio State University (Professor Mark Walter) 

12 th Annual SECA Workshop: July 28, 2011 Project Invent, Develop, Deliver. Objectives Overall Project Goal Validate performance, robustness, cost and scalability of  NexTech’s FlexCell planar cell design for coal-based SOFC power systems Phase I Objectives Demonstrate that high performance can be achieved in  FlexCells made with YSZ as the electrolyte material Demonstrate that FlexCells have sufficient mechanical  robustness for SOFC applications Demonstrate potential of achieving cell manufacturing cost  of less than $50/kW

12 th Annual SECA Workshop: July 28, 2011 Conclusions Invent, Develop, Deliver. Fabrication methods for ScSZ-based FlexCells were  successfully transferred to YSZ-based FlexCells . YSZ-based FlexCells successfully scaled to 500-cm 2  area. High performance in YSZ-based FlexCells has been  demonstrated at the single-cell (and stack) level. Finite element analysis is an effective design tool  for mechanically robust FlexCell architectures. Cell manufacturing cost was estimated to be  $51/kW at 250 MW/year scale

12 th Annual SECA Workshop: July 28, 2011 Invent, Develop, Deliver. Introduction to the FlexCell

12 th Annual SECA Workshop: July 28, 2011 Introduction Invent, Develop, Deliver. to the FlexCell Attributes Thin-electrolyte for high  performance Small repeat units for high  power density Dense perimeter for ease  of sealing Thin electrodes to  facilitate gas diffusion Thin anode for redox  cycling tolerance Electrode material flexibility 

12 th Annual SECA Workshop: July 28, 2011 1.2 T = 800ºC (H 2 /N 2 ) 0.8 Invent, Develop, Deliver. Power Density (W/cm 2 ) Cell Potential (volts) 0.9 0.6 Performance 0.6 0.4 Attributes 0.725 W/cm 2 0.3 0.2 (0.701 V @ 1.036 A/cm 2 ) 81% fuel utilization 0.0 0.0 1.2 0.4 A = 81 cm 2 , T = 800ºC, H 2 O/CH 4 = 3/1 0.0 0.2 0.4 0.6 0.8 1.0 1.2 Power Density (W/cm 2 ) 1.0 Cell Potential (volts) Current Density (A/cm 2 ) 0.3 0.8 High power density 0.6 0.2 and high fuel utilization 0.4 0.60 V @ 0.53 A/cm 2 0.1 U F = 95% 0.2 60% Efficiency 0.0 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 Current Density (A/cm 2 ) Internal Methane Reforming

12 th Annual SECA Workshop: July 28, 2011 1.0 T = 750ºC, J = 0.7 A/cm 2 , H 2 /air Invent, Develop, Deliver. 0.8 Potential (volts) Durability 0.6 Degradation rate = 0.67 μ V/hour (after first 100 hours) Attributes 0.4 0.2 Single-Cell Test with 4.0 T = 800ºC, J = 350 mA/cm 2 Inconel-601 Manifolds 0.0 Stack Potential (volts) 0 3,000 6,000 9,000 12,000 15,000 3.0 Time (hours) Long-Term Durability 2.0 100 mV/cell (Hybrid Cell) degradation 1.0 0.0 0 50 100 150 200 250 300 350 Time (hours) Redox Cycling Capability (3-cell stack, Hybrid Cells)

12 th Annual SECA Workshop: July 28, 2011 Invent, Develop, Deliver. Scalability to Large Areas for Higher Power Stacks 1.4 500 T = 800ºC Anode: 11.0 lpm H 2 /N 2 (50%) 1.2 Cathode: 40 lpm air 400 Cell Potential (volts) 1.0 Power (watts) 300 0.8 0.6 200 0.4 426 watts 562 A @ 0.759 V 100 0.2 U F = 71% 0.0 0 Total Cell Area: 1200 cm 2 0 100 200 300 400 500 600 Active Cell Area: 800 cm 2 Current (amps)

12 th Annual SECA Workshop: July 28, 2011 Sulfur Tolerant Stack Invent, Develop, Deliver. Operation (3-Cell Stack) 4.0 T = 800ºC J = 0.203 A/cm 2 U F = 65% 3.0 Potential (volts) 50 pmm H 2 S 2.0 Fuel Simulated ATR Reformate 34.6% H 2 8.4% CO 1.0 50 ppm H 2 S, U F = 65% 30.0% H 2 O 8.1% CO 2 18.9% N 2 0.0 0 100 200 300 400 500 Time (hours)

12 th Annual SECA Workshop: July 28, 2011 Invent, Develop, Deliver. Status of NexTech’s SOFC Stack Technology

12 th Annual SECA Workshop: July 28, 2011 Stack-Intent Invent, Develop, Deliver. FlexCells FlexCell for 1-2 kW stacks FlexCell for 5-10 kW stacks 14.6 by 22.2 cm 18.4 by 29.2 cm

12 th Annual SECA Workshop: July 28, 2011 1-kW Scale Invent, Develop, Deliver. Stack Platform Total Cell Area: 320 cm 2 Active Cell Area: 160 cm 2 30 1200 Stack Potential (volts) 25 1000 Stack Power (watts) 20 800 15 600 10 400 1.04 kW @ 0.78 V/cell 5 70% fuel utilization 200 0 0 24-Cell Stack 0 10 20 30 40 50 60 Current (amps)

12 th Annual SECA Workshop: July 28, 2011 Reproducibility Invent, Develop, Deliver. of 24-Cell Stacks 30 1200 Stack Temperature = 800ºC 26.8 lpm H 2 /N 2 , 120 lpm air 25 1000 Potential (volts) Power (watts) 20 800 15 600 Stack #128 Stack #133 10 400 Stack #134 Stack #138 5 200 Stack #142 0 0 0 10 20 30 40 50 60 Current (amps)

12 th Annual SECA Workshop: July 28, 2011 10-Cell Stack Invent, Develop, Deliver. 14 10-Cell Stack 1200 1050 12 Stack Potential (volts) Stack Power (watts) 900 10 750 5-10 kW Scale 8 600 6 450 Stack Platform 1033 W @ 132 A 4 300 0.782 V/cell U F = 70.1 percent 2 150 0 0 3-Cell Stack 0 25 50 75 100 125 150 4.0 3-Cell Stack 400 Current (amps) Stack Potential (volts) Stack Power (watts) 3.0 300 Total Cell Area: 540 cm 2 2.0 200 Active Cell Area: 300 cm 2 344 W @ 172 A 1.0 100 U F = 91.5 percent 48.5% efficiency 0.0 0 0 50 100 150 200 Current (amps)

12 th Annual SECA Workshop: July 28, 2011 Thermal Cycling Invent, Develop, Deliver. (large-area 3-cell stack) 4.0 T = 790°C Anode: 7.88 lpm H 2 /N 2 first pole curve Cathode: 28 lpm air after 1st cycle Stack Potential (volts) after 2nd cycle 3.0 2.0 U F = 70% (J = 0.441 A/cm 2 ) Degradation @ U F = 70% First pole curve: 2.28 volts 1.0 First Cycle: 1.47% After first cycle: 2.24 volts Second Cycle: 1.04% After second cycle: 2.22 volts 0.0 0 30 60 90 120 150 Current (amps)

12 th Annual SECA Workshop: July 28, 2011 New Stack Design Invent, Develop, Deliver. (higher efficiency) 1.2 0.4 1.0 Power Density (W/cm 2 ) 0.3 Potential (V/cell) 0.8 0.6 0.2 U F = 70% 0.4 H 2 /N 2 fuel, T= 800°C 0.1 9-Cell Stack (New Design) 0.2 10-Cell Stack (Original Design) 0.0 0.0 0.0 0.1 0.2 0.3 0.4 0.5 Current Density (A/cm 2 )

12 th Annual SECA Workshop: July 28, 2011 High Efficiency Invent, Develop, Deliver. Stack Operation 0.90 9-Cell Stack (160-cm 2 active area) T = 800°C, J = 0.30 A/cm 2 , 330 watts 0.85 Potential (volts/cell) 0.80 0.75 Stack: U F = 79.6% Fuel Simulated Steam Reformate LHV Efficiency: 46.0% 0.70 42% H 2 (2995 sccm) U F = 79.6% 11% CO (785 sccm) LHV Efficiency = 46.0% 0.65 16% CO 2 (1141 sccm) 31% H 2 O (2210 sccm) 0.60 0 12 24 36 48 60 72 Time (hours)

12 th Annual SECA Workshop: July 28, 2011 Ongoing Stack Invent, Develop, Deliver. Development Activities D eveloping interconnect coating technology to  enable long-term durability and thermal cycling Completing 1-2 kW stack platform, focusing on  efficiency, durability and thermal cycling Breadboard demonstrations of SOFC power  generation using military logistic fuels Continuing development of 5-10 kW stack  platform Offering 1-kW scale stacks for evaluation by  potential partners

12 th Annual SECA Workshop: July 28, 2011 Invent, Develop, Deliver. Fabrication and Testing of YSZ-Based FlexCells (SECA Project)

12 th Annual SECA Workshop: July 28, 2011 Fabrication of Invent, Develop, Deliver. YSZ-Based FlexCells Architecture Variables Support thickness: 80-160 μ m  Membrane thickness: 24-32 μ m  Percent thin membrane in active  region: 65-75 percent Support mesh pattern/geometry 

12 th Annual SECA Workshop: July 28, 2011 YSZ Based FlexCell Invent, Develop, Deliver. 1.2 1.2 A = 28 cm 2 Fuel: 450 sccm H 2 Power Density (W/cm 2 ) 1.0 1.0 Cell Potential (volts) 0.8 0.8 0.6 0.6 0.4 0.4 850ºC: ASR = 0.20 Ω -cm 2 0.2 0.2 800ºC: ASR = 0.27 Ω -cm 2 750ºC: ASR = 0.42 Ω -cm 2 0.0 0.0 0.0 0.3 0.6 0.9 1.2 1.5 Current Density (A/cm 2 )