Periodic Report Summary - METSOFC (Development of next generation metal based SOFC stack technology)
Today ceramic anode-supported solid oxide fuel cells (SOFCs) represent the state of the art with respect to high-temperature fuel cells. However the use of ceramic SOFCs inherently imposes limits in terms of reliability, cost and ability to handle transients.
The objective of the METSOFC project was to develop the next generation of metal based SOFC stack technology. Within the project metal supported SOFCs would be developed and tested and new metallic stack materials would be developed and tested as well, including new robust insulating seals between layers. Finally, the developed stacks would be tested up to the 1 kWe level.
The METSOFC project consisted of six work packages (WPs):
1. WP1: Product and test definition
2. WP2: Materials and components
3. WP3: Cells
4. WP4: Stacks
5. WP5: Testing
6. WP6: Dissemination and exploitation of project results.
The METSOFC consortium comprised a strong vertically integrated team, representing all core competences necessary to carry out the development. Between them, the partners had the sufficient experience and position to ensure that the technology developed would be market oriented and industrially relevant. The members of the METSOFC consortium were also selected to provide the leanest and most efficient organisation possible. All the members had prior collaboration experience in other bilateral and multilateral partnerships.
Metal based SOFC stack technology would improve functionality, reliability and reproducibility and reduce manufacturing cost of SOFC stacks, in particular for auxiliary power unit (APU) applications which required fast start up and thermal cycling, carbon containing fuel gas, high current density, chock vibration resistance, fast transients in electrical loads and red-ox cycling. Current state of the art anode supported cells relied upon nickel and zirconia materials that would not be able to meet neither the technical requirements, nor the future allowable total cost for SOFC systems, such as the approximately EUR 350 per kW.
The objective of the METSOFC project was to develop cells and stacks that relied upon cheaper metallic materials aiming at commercial competitiveness of the SOFC technology in the transportation segment. The project featured a novel initiative to develop and test SOFC stack that tolerated mechanical shock and vibration. Particularly for that purpose, a reliability assessment and allocation technique, developed previously for advanced automotive component development, was adopted and first time applied in fuel cell research.
The metal based stack technology would also facilitate the development towards lower operating temperature, which would lead to additional cost savings and increased durability in the SOFC balance of plant.
The work performed since the beginning of the project could be summarised as follows. Firstly, in WP1 'Product and test definition', all the planned work was completed in February 2009. The work encompassed:
1. specification of a cost-competitive and efficient SOFC-APU system based on METSOFC technology for heavy duty mobile applications and identification of suitable near- and long-term fuels,
2. definition of test procedures for single cell performance tests, single cell durability tests and stack performance and vibration tests, and
3. detailed requirements for the METSOFC cells and stacks in mobile applications.
In WP2 'Materials and components', the work on defining and applying the most suitable coatings in pre-coated stainless steel strips for interconnects included the production and evaluation of a first set of samples, the production of optimized pre-coated samples and a first production scale test of coated steel. The work on development of metal powders for metal supported cells included the definition, production and evaluation of five different metal powders.
The work in WP3 'Cells' during the first two reporting periods was concentrated on SoA and 1G metal supports and cells. The work encompassed:
1. metal support development,
2. corrosion testing of metal supports,
3. integration of the metal support into a cell and cell production, and
4. mechanical characterization of metal supported SOFC.
The focus of the work in WP4 'Stacks' was on the development of appropriate stack technology for metal supported cells. A number of small stacks were built to evaluate the stack repeatable units and stack sealing technologies. The first METSOFC test stack was built and sent to AVL for performance testing.
The cell tests performed so far in the METSOFC project included several tests, as part of WP5, to characterize and evaluate cell performance, cycling and long term durability, as well as to determine loss mechanisms. The first METSOFC test stack was tested at AVL in July 2010. The test facility for stack vibration tests, or 'shaker tests', was established and testing was performed for a state of the art stack with ceramic anode supported cells.
In WP6 'Dissemination', a public METSOFC project website was established at the address www.metsofc.eu. Project results from the METSOFC project were presented at the European Fuel Cell Forum in Lucerne from 29 June to 2 July 2010.
The main results so far in the METSOFC project were the following:
1. the product definition and test plan milestone by the end of WP1 was met in February 2009
2. improved pre-coated materials for stainless steel strips for interconnects were found and were under evaluation through first production scale tests
3. a new metal powder for metal supports was found with potential improvements compared to the SoA metal supports
4. cell production was challenging due to many unforeseen upscaling difficulties; however, many of the crucial fabrication parameters were determined and solved, resulting in that a number of leak tight (1G) cells of 12 times 12 cm2 were fabricated
5. the cell performance of SoA metal supported cells on 5 times 5 cm2 cells was comparable or even better than conventional SoA anode supported cells. ASR values of less than 0.8 ?cm2 at 650 ºC were obtained when using various simulated diesel reformate fuels such as hydrogen (H2), carbon monoxide (CO), water (H2O), carbon dioxide (CO2) and nitrogen (N2) mixtures. With hydrogen as fuel an ASR of less than 0.55 ?cm2 at 650 ºC was shown on SoA cells.
6. the SoA metal supported cells showed excellent redox tolerance. They underwent an endurance test of 100 redox cycles at 800 ºC without severe degradation or total failure. The long term durability was also considerably improved. At 650 ºC, the initial ASR of a specific SoA cell was 0.64 ?cm2 and it showed a degradation of approximately 1% per khr when tested for 3 000 h.
7. a solution was found for stack repeatable units and an appropriate sealing technique for stacks with metal supported cells seemed to be available
8. an experimental set up for three-axis vibration testing of up to 9g and 1 kHz of SOFC stacks under real world conditions, i.e. at operating temperature and with fuel gas supply, was developed.
The expected final results and their use could be summarised in the following way:
1. stacks with metal supported SOFC cells that were tested up to the 1 kWe level
2. suitable for APU systems where the combination of fuel flexibility and robustness was required
3. metal supported cells and stacks could be also suitable for stationary applications. The METSOFC partners decided to pursue this in the subsequent project 'Metsapp', which was applied for in the fuel cells and hydrogen (FCH) joint undertaking (JU) third call for applications.
Further information about the project could be obtained at 'www.metsofc.eu'.
The objective of the METSOFC project was to develop the next generation of metal based SOFC stack technology. Within the project metal supported SOFCs would be developed and tested and new metallic stack materials would be developed and tested as well, including new robust insulating seals between layers. Finally, the developed stacks would be tested up to the 1 kWe level.
The METSOFC project consisted of six work packages (WPs):
1. WP1: Product and test definition
2. WP2: Materials and components
3. WP3: Cells
4. WP4: Stacks
5. WP5: Testing
6. WP6: Dissemination and exploitation of project results.
The METSOFC consortium comprised a strong vertically integrated team, representing all core competences necessary to carry out the development. Between them, the partners had the sufficient experience and position to ensure that the technology developed would be market oriented and industrially relevant. The members of the METSOFC consortium were also selected to provide the leanest and most efficient organisation possible. All the members had prior collaboration experience in other bilateral and multilateral partnerships.
Metal based SOFC stack technology would improve functionality, reliability and reproducibility and reduce manufacturing cost of SOFC stacks, in particular for auxiliary power unit (APU) applications which required fast start up and thermal cycling, carbon containing fuel gas, high current density, chock vibration resistance, fast transients in electrical loads and red-ox cycling. Current state of the art anode supported cells relied upon nickel and zirconia materials that would not be able to meet neither the technical requirements, nor the future allowable total cost for SOFC systems, such as the approximately EUR 350 per kW.
The objective of the METSOFC project was to develop cells and stacks that relied upon cheaper metallic materials aiming at commercial competitiveness of the SOFC technology in the transportation segment. The project featured a novel initiative to develop and test SOFC stack that tolerated mechanical shock and vibration. Particularly for that purpose, a reliability assessment and allocation technique, developed previously for advanced automotive component development, was adopted and first time applied in fuel cell research.
The metal based stack technology would also facilitate the development towards lower operating temperature, which would lead to additional cost savings and increased durability in the SOFC balance of plant.
The work performed since the beginning of the project could be summarised as follows. Firstly, in WP1 'Product and test definition', all the planned work was completed in February 2009. The work encompassed:
1. specification of a cost-competitive and efficient SOFC-APU system based on METSOFC technology for heavy duty mobile applications and identification of suitable near- and long-term fuels,
2. definition of test procedures for single cell performance tests, single cell durability tests and stack performance and vibration tests, and
3. detailed requirements for the METSOFC cells and stacks in mobile applications.
In WP2 'Materials and components', the work on defining and applying the most suitable coatings in pre-coated stainless steel strips for interconnects included the production and evaluation of a first set of samples, the production of optimized pre-coated samples and a first production scale test of coated steel. The work on development of metal powders for metal supported cells included the definition, production and evaluation of five different metal powders.
The work in WP3 'Cells' during the first two reporting periods was concentrated on SoA and 1G metal supports and cells. The work encompassed:
1. metal support development,
2. corrosion testing of metal supports,
3. integration of the metal support into a cell and cell production, and
4. mechanical characterization of metal supported SOFC.
The focus of the work in WP4 'Stacks' was on the development of appropriate stack technology for metal supported cells. A number of small stacks were built to evaluate the stack repeatable units and stack sealing technologies. The first METSOFC test stack was built and sent to AVL for performance testing.
The cell tests performed so far in the METSOFC project included several tests, as part of WP5, to characterize and evaluate cell performance, cycling and long term durability, as well as to determine loss mechanisms. The first METSOFC test stack was tested at AVL in July 2010. The test facility for stack vibration tests, or 'shaker tests', was established and testing was performed for a state of the art stack with ceramic anode supported cells.
In WP6 'Dissemination', a public METSOFC project website was established at the address www.metsofc.eu. Project results from the METSOFC project were presented at the European Fuel Cell Forum in Lucerne from 29 June to 2 July 2010.
The main results so far in the METSOFC project were the following:
1. the product definition and test plan milestone by the end of WP1 was met in February 2009
2. improved pre-coated materials for stainless steel strips for interconnects were found and were under evaluation through first production scale tests
3. a new metal powder for metal supports was found with potential improvements compared to the SoA metal supports
4. cell production was challenging due to many unforeseen upscaling difficulties; however, many of the crucial fabrication parameters were determined and solved, resulting in that a number of leak tight (1G) cells of 12 times 12 cm2 were fabricated
5. the cell performance of SoA metal supported cells on 5 times 5 cm2 cells was comparable or even better than conventional SoA anode supported cells. ASR values of less than 0.8 ?cm2 at 650 ºC were obtained when using various simulated diesel reformate fuels such as hydrogen (H2), carbon monoxide (CO), water (H2O), carbon dioxide (CO2) and nitrogen (N2) mixtures. With hydrogen as fuel an ASR of less than 0.55 ?cm2 at 650 ºC was shown on SoA cells.
6. the SoA metal supported cells showed excellent redox tolerance. They underwent an endurance test of 100 redox cycles at 800 ºC without severe degradation or total failure. The long term durability was also considerably improved. At 650 ºC, the initial ASR of a specific SoA cell was 0.64 ?cm2 and it showed a degradation of approximately 1% per khr when tested for 3 000 h.
7. a solution was found for stack repeatable units and an appropriate sealing technique for stacks with metal supported cells seemed to be available
8. an experimental set up for three-axis vibration testing of up to 9g and 1 kHz of SOFC stacks under real world conditions, i.e. at operating temperature and with fuel gas supply, was developed.
The expected final results and their use could be summarised in the following way:
1. stacks with metal supported SOFC cells that were tested up to the 1 kWe level
2. suitable for APU systems where the combination of fuel flexibility and robustness was required
3. metal supported cells and stacks could be also suitable for stationary applications. The METSOFC partners decided to pursue this in the subsequent project 'Metsapp', which was applied for in the fuel cells and hydrogen (FCH) joint undertaking (JU) third call for applications.
Further information about the project could be obtained at 'www.metsofc.eu'.