Ceres Power cell technology is based on a patented steel cell using cerium gadolinium oxide (CGO) as the electrolyte, thus permitting operating temperatures of 500-620 °C compared to ≥700 ˚C for conventional SOFCs using yttria stabilized zirconia (YSZ) electrolyte. Further, the use of a metal support allows much greater mechanical robustness than is typically the case with a planar ceramic SOFC, while maintaining the high volumetric power density typical of planar SOFCs.

The combination of low operating temperature—with the related ability to use lower cost materials—metal support and careful optimization of the microstructure of the ceramic layers allows low cell, stack and balance of plant cost and high robustness to real-world operating conditions.

SOFC technology in principle offers the possibility of very high efficiency electrical power generation from either hydrocarbon fuels or hydrogen, and thus if adopted widely has the potential to significantly reduce primary energy consumption and the associated carbon dioxide emissions. Whilst considerable progress has been made in the development of SOFC technology towards competitiveness with more established power generation technology, a number of inherent problems remain with conventional ceramic-based SOFC technology.

The key challenges associated with conventional SOFC technology are mostly related to the high cost of cell, stack and balance-of-plant components, and robustness to real-world operating conditions, particularly unplanned fuel interruptions at operating temperature and thermal cycling. The high cost of components makes it difficult to make SOFC-based power generation systems which have compelling consumer business cases without government subsidy. The poor robustness to likely real-world operating conditions either reduces product life or drives complexity, as additional systems are required to protect the SOFC stack from the effect of failures elsewhere.

Ceres Power has developed a novel and highly differentiated SOFC technology based upon the use of thick-film ceramics deposited upon a ferritic stainless steel substrate, using doped ceria as the predominant oxygen-ion conducting ceramic within the cell.

—Leah et al. (2015)

Ceres Power fabricates the individual Steel Cells by screen printing layers of ceramic ink onto a drilled sheet of steel. Achieving these high quality ceramic layers at low temperature on steel is the core of Ceres’ intellectual property. Exclusive to Ceres is the use of Ceria in the anode and electrolyte. Ceria is as abundant as copper and is used industrially for dyeing glass, self-cleaning ovens and catalytic converters in cars.

Schematic representation of a Ceres Power Steel Cell. Leah et al. (2015) Click to enlarge.

The new high-speed print line at Ceres’ manufacturing facility in Horsham has reduced ceramic on steel print-cycle time from 30 seconds to just 3 seconds, representing a 10-fold increase in processing speed, demonstrating that Ceres’ processes are consistent with low-cost, high-volume manufacturing and corroborating the Steel Cell as a potentially disruptive low-cost fuel cell technology.

This project has been successfully delivered by Ceres in partnership with ASM Alternative Energy (ASM AE), the global provider of screen printing equipment and part-funded by £0.7 million (US$1 million) from Innovate UK’s Advanced Manufacturing Supply Chain Initiative. By using standard processes developed for the solar industry and conventional materials such as steel, this project has been key to demonstrate that the Steel Cell can be mass-produced at an affordable price.

The innovative print line is the first of its kind and has been created by combining ASM AE’s existing high-speed photovoltaic manufacturing processes and Eclipse printing solutions with Ceres’ own existing manufacturing capabilities.

Ceres sees growing opportunities for its fuel cell technology across a range of mass-market power applications and is working with leading power systems companies worldwide, including Honda, as noted earlier, as it delivers against its strategy of establishing the Steel Cell as the platform of choice for future power products.

Resources

(A hat-tip to David!)

• Robert Timothy Leah, Adam Bone, Mike Lankin, Ahmet Selcuk, Mahfujur Rahman, Andrew Clare, Lee Rees, Stephen Phillip, Subhasish Mukerjee, and Mark Selby (2015) “Ceres Power Steel Cell Technology: Rapid Progress Towards a Truly Commercially Viable SOFC,” ECS Trans. 68(1): 95-107; doi: 10.1149/06801.0095ecst

• R. Leah, A. Bone, M. Lankin, A. Selcuk, R. Pierce, L. Rees, D. Corcoran, P. Muhl, Z. Dehaney-Steven, C. Brackenbury, M. Selby and S. Mukerjee (2013) “Low-Cost, REDOX-Stable, Low-Temperature SOFC Developed by Ceres Power for Multiple Applications: Latest Development Update” ECS Transactions, 57 (1) 461-470 doi: 10.1149/05701.0461ecst