SOFC Stack Modules for Decentralized Power ... - Fuel Cell Markets

SOFC Stack Modules for Decentralized Power Generation

Your Heart of Energy
Customers around the world are demanding
services at lower cost and with less environmental
impact. Electricity generation based
on high efficiency solid oxide fuel cells
(SOFC) is best able to meet this need.
The main barrier to market entry has been,
until now, the supply of a robust and stable
SOFC stack.
staxera has solved this problem and now
offers its integrated stack module (ISM) in
volume and at low cost. The ISM is the heart
of any SOFC energy conversion system.
This product provides staxera’s customers
with the opportunity to develop SOFC systems
and then to enter and dominate the
market for decentralized power generation.
staxera is the world leading supplier of solid
oxide fuel cells for SOFC systems – the only
supplier with the staxera advantage.

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Ready to deliver
staxera’s SOFC integrated stack modules (ISMs) are available immediately in
volumes of up to 500 units per year. Standardized ISMs can be supplied for
initial system development and customized ISMs can be developed to allow even
tighter system integration. High volume manufacture (up to 50.000 units per
year) is possible within two years, allowing for the construction of a new manufacturing
hall, installation of automated assembly equipment, and commissioning.
Security of supply
n active in more than 58 countries
n automobile component supplier
n 1.6 billion € turnover in 2008
n 7.5% investment of turnover in R&D
n more than 7000 employees
staxera GmbH is stably and securely held by Webasto AG, a German family
owned company and one of the world’s 100 largest automobile component
suppliers.
staxera was previously a 50:50 joint venture between We-
basto AG and H.C. Starck. Webasto AG obtained full
control of staxera by purchasing H.C. Starck’s
50% shareholding in late 2009. H.C. Starck
remains staxera’s cell supplier and development
partner. Webasto AG and staxera
GmbH are committed to the long term
development of SOFC as a key component
in the world’s clean tech future.
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Mk200 SOFC stack
The staxera Mk200 stack was developed using a top-down design process based
on clear system requirements for low cost, low pressure drop and robust operation.
Stamped sheet metal interconnects provide low cost while ESC cells provide thermal
and redox stability.
The stack is compatible with a wide variety of fuel
gases, including CPOX and steam reforming. Air
flow can be either co-flow or counter-flow, simply by
selecting which side to use as the air inlet.
staxera has developed a deep understanding of the
temperature gradients and thermomechanics occuring
within the Mk200 stack. This enables us to optimize
the design and deliver world-class robustness
and endurance.
Low anode and cathode pressure drops help to minimize
system parasitic losses, while an open cathode
allows tight system integration if desired.
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Integrated stack module (ISM)
The staxera ISM provides the critical functional en-
vironment for the SOFC stack, thereby allowing
rapid system integration and robust performance.
Clearly defined interfaces for gases, sensors and
electrical current are provided, as well as components
for compression loading, thermal insulation,
cathode manifolding; and pressure, voltage and
temperature measurement.
Using this approach staxera guarantees 5.000 hours
of operation and 20 thermal cycles when the ISM is
operated within pre-defined parameters.
The ISM is presently available with a rated power of
1.1 kW at a fuel utilization of 75%. Future ISMs will
have increased power, reduced heat loss, and higher
limits for fuel utilization.
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Your heart of energy
staxera delivers ISMs worldwide to a large variety of industrial customers,
supporting individual requirements whilst maintaining complete confidentiality.
The ISM forms the heart of each customer's energy conversion system.
Several of staxera’s customers are shown here.
EBZ GmbH has developed a 3 kW system demonstrator based on
steam reforming of natural gas. This system can be modified to suit
a range of fuels such as biogas and landfill gas; and is also capable
of acting as a combined heat and power (CHP) system. The system
is available for purchase – please contact www.ebz-dresden.de for further details.
Vaillant GmbH is one of
Europe’s largest manufacturers
of heating, ventilation and air conditioning
systems. Vaillant is developing a 1 kW microCHP
system for single family houses. Vaillant selected the
staxera SOFC as it's basis for a microCHP system
over competing technologies such as stirling engines,
PEM fuel cells and internal combustion engines.
Callux is Germany’s big-
www.callux.net
gest practical test project
for small residential fuel cell based heating systems.
As part of the National Innovation Program for Hydrogen
and Fuel Cell Technology (NIP), industry and
government are together investing 1 billion € to
promote this innovative concept. More than 50 fuel
cell heaters are already up and running, and by the
end of 2012 some 800 units will undergo trials.
A significant number of these units will be constructed
by Vaillant using ISMs from staxera.
Continuous improvement
staxera has been developing SOFC stacks since the company was founded in
2005. Products have been sold on the open market since 2006, when the
Mk100 stack was first introduced. Each year thereafter has seen continuous
improvement in staxera’s products, including the higher power Mk200 stack in
2007 and the integrated stack module (ISM) in 2008.
The ISM is now staxera’s main product, owing to its defined interfaces and ease
of use. Since 2009 staxera’s has supplied large customers with customized
ISM designs, according their individual requirements.
2006 2007 2008 2010
Year Company improvement
2005 Company founded
2006 Mk100 stack, 350 W
2007 Mk200 stack, 500 W
2008 Integrated stack module (ISM), 1 kW
2009 ISM 1.1 kW, customer specific solutions
2010 ISM 1.4 kW
2011 ISM 1.7 kW
2012 ISM 3 kW
2013 ISM 5 kW
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staxera advantage
SOFC system developers can save time and reduce cost and risk by sourcing ISMs from staxera. This
produces the best possible business case for the SOFC developer – the staxera advantage.
Time to market
The ISM is available immediately in volumes of up to 500 units per year. Standardized ISMs can be supplied
for initial system development, and customized ISMs can be developed to allow even tighter system integration.
High volume manufacture (up to 50.000 units per year) is possible within two years, allowing for
the construction of a new manufacturing hall.
Development cost and production cost
Sourcing ISMs from staxera is cheaper than either developing a new SOFC stack design or manufacturing
at a separate facility. staxera has already developed the stack, together with a family of proprietary and pa-
tented production processes. SOFC production costs are strongly dependent upon production volume,
and our customers benefit from staxera’s quantity of scale. In series production the profit margins from
staxera will be comparable with suppliers from the automotive industry.
Backup by broad R&D support
staxera’s technical results are backed by a multi-year joint research program between the Fraunhofer IKTS
and staxera. IKTS is investigating the degradation mechanisms of interconnector steels, contact elements
and sealing glasses, and the results of this work will lead to a new generation of materials and therefore to
improved stack performance. This deep understanding of failure mechanisms substantially reduces our customer’s
long term development risk.
Technical risk
The optimum performance of SOFC stacks in a system environment requires specific stack characteristics.
These are not obvious if you start with a bottom up stack development program from cells to stacks.
staxera has manufactured and tested hundreds of stacks; has conducted an initial HAZOP analysis; and
has improved the design accordingly.
staxera’s expertise is SOFC stack engineering de-
sign and manufacture, focussing on thermomechanics,
tolerances and scale up.
Fraunhofer IKTS is staxera’s R&D partner, focus-
sing on materials science, sealing glasses, contact
pastes and protective coatings.
H.C. Starck is staxera’s cell, paste, and glass sup-
plier; with a manufacturing capacity of 3 million cells
per year.
ThyssenKrupp VDM is staxera’s supplier for high
temperature ferritic sheet steel, optimized for SOFC
operation.
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Technical performance
ISMs from staxera have excellent technical performance in the critical areas of power, thermal cycling,
lifetime and redox stability. These parameters are absolutely crucial for successful system performance.
Power
The staxera SOFC stack delivers both high power and high efficiency, owing to
it’s capacity to operate at 75% fuel utilization.
Thermal cycling
staxera has demonstrated 150 thermal cycles with a 30-cell Mk200 stack, and
50 thermal cycles with a ISM. This is world class performance.
Lifetime
staxera has demonstrated over 10.000 hours of stable operation on both the older
Mk100 and the present Mk200 stack designs, with degradation less than 0.4%
per 1.000 hours. Commercial targets are between 40.000 and 80.000 hours.
Redox stability
ESCs have excellent redox stability as the anode (which expands and contracts
as it oxidizes and reduces) is very thin, and is supported by the thicker electrolyte.
The power delivered by a staxera ISM is dependent upon the fuel composition, fuel utilization and the
operating temperature. To improve our customer service staxera has selected one reference operating
condition which all organizations can reproduce:
n fuel composition of 40% hydrogen and 60% nitrogen
n fuel utilization of 75%
n operating temperature 850°C
The diagram above shows the power as a function of current at the reference operating condition, and
also at two other typical gas compositions.
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SOFC stacks must be able to operate reliably and stably over a long period of time. For typical
applications such as microCHP or decentralized power generation, our customers require a lifetime
of at least 40.000 hours, with some customers requiring 80.000 hours. The degradation
over this time period must usually be less than 0.5% per 1.000 hours.
staxera has conducted endurance tests of over 10.000 hours with both the older Mk100 stack design
and the present Mk200 stack design. The diagram above shows that the total stack degradation after
12.000 hours is less than 4%, which translates to less than 0.4% per 1.000 hours.
Since this data was collected staxera has improved the cycling capability of the Mk200 stack, which
should prevent sharp changes in degradation as observed at 7.500 hours above. Until this time, the
stack had a total degradation of less than 0.1% per 1.000 hours.
SOFC stacks must be able to turn on and off with the SOFC system. This is called thermal cycling,
and the number of cycles required is dependent upon each customer and each system application. The
diagram above shows that the Mk200 stack can survive over 160 complete power and thermal cycles.
The stack cycles between 850°C and 100°C, and also between full load (22 A) and no load. This is
world class performance.
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3 kW system demonstrator
The 3 kW system demonstrator is a product from the
company EBZ GmbH, which is also located in Dresden,
Germany. EBZ and staxera cooperated on the
development of this system.
The system was developed to show that the staxera
ISM can operate reliably and efficienctly when fuelled
with steam reformate, particularly with internal reforming.
Secondly, the system is intended as the first
step towards 20 kW systems for decentralized electricity
generation.
The 3 kW system demonstrator is designed for a peak
stack power of 3 kW, using two staxera ISMs, each
with a peak power of up to 1.5 kW. At present the
system is operating with two 1.1 kW ISMs. Future
systems will have a power output of 5 kW and then
20 kW. staxera and EBZ are seeking an industrial
partner for this project.
The 3 kW system demonstrator is the ideal platform for SOFC system research
and development. Control strategies can be adjusted and some components
(such as ISM, blowers) can be exchanged.
Customized solutions
The system is able to be modified to suit each customer’s individual requirements.
For example, for operation with biogas or LPG, or with power levels from
1 to 5 kW. For more details please contact EBZ directly: www.ebz-dresden.de
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Your Heart of Energy
staxera is committed to supplying the highest
quality SOFC stacks in the world, with excellent
customer service. Please do not hesitate
to contact us for further information.
staxera GmbH 2010
staxera GmbH
Gasanstaltstraße 2
01237 Dresden . Germany
phone: +49-351-896797-0
fax: +49-351-896797-831
info@staxera.de
www.staxera.de

staxera GmbH | Gasanstaltstraße 2 | 01237 Dresden . Germany | phone: +49-351-896797-0 | www.staxera.de