DEPARTMENT OF APPLIED ELECTROCHEMISTRY

© Fraunhofer ICT

Fraunhofer Institute for Chemical Technology ICTDr. Duygu Karabelli, M.Sc. Burak Caglar

Thomas Berger, Dr. Peter Fischer, Dr. Carsten Cremers, Dr. Karsten Pinkwart, Dr. Jens Tübke

DEPARTMENT OFAPPLIED ELECTROCHEMISTRY

© Fraunhofer ICT

Applied Electrochemistry-Fraunhofer ICT

Established 1972

Location Pfinztal-Berghausen

Staff (full-time equivalent) 80 (approx. 45)Scientists, PhD candidates 28Graduates, laboratory technicians 19Workshop and laboratory assistants 10Administration 2Trainees 21

Budget 2010 (only ICT Pfinztal) 3.8 million €

Total site area 700 m2

Laboratories, pilot plants approx. 500 m2

Test sites approx. 200 m2

Stand 31.12.2010

© Fraunhofer ICT

Batteries

T. Berger

Fuel Cells

Dr. C. Cremers

Redox-Flow-Batteries

Dr. P. Fischer

Sensors andAnalytical Systems

P. Rabenecker

Director

Dr. J. Tübke, Dr. K. Pinkwart

Project Group „Mobility“ Wolfsburg

Dr. J. Tübke

Applied Electrochemistry

Project Group „Electrochemical Storage Systems“

Dr. J. Tübke, Dr. Kai-Christian Möller

© Fraunhofer ICT

Applied Electrochemistry – Research since 1970

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Electrochemical direct conversion of ammonia for fuel cells

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Measurement methods for the comparative study of primary batteries

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Solar power generator for low power range

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Hydrogen storage with reversible metalhydrid

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Redox-Flow Batteries for renewable energy storage

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Methylated spirits for fuel cells

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Active and passive measurements for intrinsically safe lithium-ion batteries

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Materials• Test cell development.

material tests• Solid state ion

conductors• S- und O- cathodes• Alkaline -anodes

Cell Development• Pouch cells• Cell design > 40 Ah• Electrical and thermal

cell characterisation

Safety andPerformance• Standard tests up to

40 kWh / module• Customer – specific

measurements• Gas analysis• Simulation

Applied ElectrochemistryBatteries

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© Fraunhofer ICT

Lithium Batteries

Electrode materials Cathodes for Li-S and Li-O batteries

Electrolytes and separators Ionic liquids, polymer gel electrolytes and

ceramic separators, e.g. for lithium-ion andlithium batteries

Material tests

Testing and benchmarking of electrode materials, electrolytes and separators

Construction of laboratory test cells

Construction of sample cells Demonstrator cells with a pouch design

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© Fraunhofer ICT

Advantages of the Li-S system

Sulfur is cheap (70-600 $/t [1] ; LIB-material >10.000 $/t [2] )

Abundant resources

Highest theoretical capacity of solid cathode materials (1672 mAh/g sulfur)

Energy densities between 200-500 Wh/kg

Cathode production with existing Li-Ion technology

1: U.S. Geological Survey, Mineral Commodity Summaries, January 2009

2: W.F. Howard, R.M. Spotnitz: Journal of Power Sources 165 (2007) 887–891

Disadvantages of the Li-S Systems

Low cell voltage (2.2 V vgl. LIB ~3.7V)

High self discharge

Sulfur is isolator

Low cycle stability(~200 cycles)

Shuttle mechanism

Lithium-Sulfur High Energy Cells

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© Fraunhofer ICT

Lithium-Sulfur Batteries - Targets

Lower costs for electrode compared to LIB

Higher energy density than LIB ( 300-600 Wh/kg)

Comparable cycle life (> 2000 cycles)

Solving of the „shuttle mechanism“

Problem (self discharge, no full charge)

Lithium-anode

Separator

Sulfur cathode

Current collector

Current collector

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CNT electrode (side view) CNT-S electrode (bird‘s eye view)

Lithium-Sulfur Batteries – Fraunhofer Approach

Ni substrate

CNT

CNT

sulfur‐coated CNT

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Vertical alligned CNT synthesized directly on the current collector

No binder, no additional conductive carbon

80 - 90 % sulfur weight percentage of electrode!

© Fraunhofer ICT

Experiment Results - Capacity – organic electrolyte

90 % sulfur in electrode

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Li-O2 Batteries

Advantages of the Li-O system

Very high possible energy densities ~ 1,000 Wh/kg

Oxygen can be taken out of the air

Cost effective catalysts

Higher average discharge voltage than Li-S (2.7 V)

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Energydensity

Cost Lifetime Safety

State of theart

Theoretical: 11680 Wh/kg

Pratical: 1700 Wh/kg

Ratio: 14,5%

Cost-effectivecatalysts

Demonstratedlife up to about

50

Thermal runaway not

possible

Lithium metal: well-known

safety problem

Future research

Increase of theratio

Increase of thevolumetric

energy density

Development ofmanufacturing

equipment

Better design

Higher numberof charge cycles

needed

Safer anodealternatives

Lithium-Air Batteries - Targets

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© Fraunhofer ICT

Air electrode: coated carbon cloth with high specific surface area

Composition of the air electrode 5% PTFE 30% MnO2 nanowires 65% Carbon

Lithium-Air Batteries – Fraunhofer Approach

High capacity Good capacity retention

Capacity over cycle life at 0.1 mA/cm2 in 0.7 M LiTFSI/TEGDME. Catalyst: 30% MnO2. Capacity in mAh/gelectrode (carbon + catalyst + PTFE, without substrate)

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Batteries – Safety Tests

FreedomCAR – Electrical Energy Storage Systems Abuse Test Manual for Electricand Hybrid Vehicle

VDA test specification for lithium ion batteries for hybrid vehicle

Tests for the UN Regulations on Transport of Dangerous Goods ADR 2003, IATA DGR 2003 und IMDG Code 2002)

Other tests (e.g. UL 1642)

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EUCAR Hazard Level´s

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What do we offer?

Mechanical Abuse Tests

Controlled crash, Penetration, Fall tests, Immersion…

Electrical Abuse Tests

Overcharging, Short-circuiting/partial short-circuiting, Forced discharge/voltage reversal

Thermal Abuse Tests

Thermal stability, Simulated fuel fire, Storage at high temperature

Rapid charging/discharging, Rapid temperature cycling

Analytical Methods and Equipment

Climate and test chambers, Corrosion (saltfog or noxious gases)

Cyclic voltammetry, Impedance spectroscopy

Differential electrochemical mass spectroscopy

Battery testing facility for safety investigations © Fraunhofer ICT

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Climate chamber© Fraunhofer ICT

Inflated pouch cell© Fraunhofer ICT

© Fraunhofer ICT

Non-Destructive Testing

Cell Tester -64 Channels

Voltage ± 5 V, Current ± 3 A

Integrated impedance measurement up to 300 kHz


Voltage -3 bis +10 V

Current ± 4 A


Voltage 0 bis 6 V

Current ± 40 A

Module Testing Unit

6 channels, regenerative, impedance measurement

Data logger (voltage, temperature)

Voltage 0 – 60 V

Current ± 300 A

Battery module developed at Fraunhofer ICT

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© Fraunhofer ICT

Non-Destructive Testing

Pack Testing Unit

2 channels, regenerative

Data logger (voltage, temperature)

Voltage 10 – 1000 V

Current ± 300 A

Shaker Unit with Sliding Table

Frequency range 5 – 3000 Hz

Sine-wave/random noise 18 kN, Schock40 kN

Vibration amplitude +/- 26,0 mm

Acceleration 833 m/s² under shock operation with test sample mass up to 25 kg

Maximum test sample load 300 kg

Sliding table surface 600 x 600 mm

Shaker unit with sliding table© Fraunhofer ICT

Drop-Shock Tester

Test sample masses of up to 85 kg

Semi sine-wave 150 g Duration: 6 mm

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© Fraunhofer ICT

MaterialMaterial StackStack SystemSystem SimulationSimulation

• Development • Test and

Characterization• Alternative battery-

chemistry• Long-Term durability

tests

• Cell- and Stack design

• Prototype-development

• Characterization• Aging tests

• System design• Demonstrator• Automation• Battery-

management• Thermal Balance

• Coupled models of electrochemistry and flow

• Leak-current simulation

• Microgrids

Applied ElectrochemistryRedox-Flow-Batteries

© Fraunhofer ICT

Redox-Flow Battery

Material development and testing Electrode materials Separators Electrolytes Long-duration tests, simulations, aging

Stacks and systems Stack design and development Construction of prototypes Feasibility studies System integration, battery

management

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© Fraunhofer ICT

Vanadium Redox-Flow-Batteries

High efficiency (>75 %) Long calendar life, excellent cycle

ability (> 10.000) Flexible design (power/energy

separate scalable) Modular design possible Fast response time (μs – ms) Over charge and over discharge

tolerant Low maintenance costs Low self discharge Low energy density (15-25 Wh/L) Corrosive media

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© Fraunhofer ICT

Vanadium / Air Redox-Flow-Batteries

MEA

Electrode

Pump

Load

- +

Electrode

Electrolyte

Air

Anode: V2+ V3+ + e-

Cathode: O2 + 4e- + H+ 2H2O

- 0,255 V vs. NHE

+ 1,2 V vs. NHE

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Redox Flow Battery – Comparison of Redox Systems

Type Energy

Density of Electrolyte

[Wh/L]

Current Density

[mA/cm²]

Power Density [W/m²

electrode]

Cell Voltage [V] (25°C, 1 mol/L

electrolyte conc.)EE

Vanadium / Vanadium 30 80 ~ 800 1,40-1,60 70 – 90 %

Vanadium / Bromine 35-70 1,34 66 – 75 %

Iron / Chromium 40 40 ~ 200 1,18 75 %

Polysulfide / Bromine 80 60 ~ 800 1,52 60 – 75 %

Zinc / Bromine 80 >100 ~ 1000 1,85 65 – 75 %

Uranium 1,00

Neptunium 1,00-1,10

Cerium / Zinc 12-20 400-500 1200-2500 2,00-2,40

Lead 75 ~ 1000 2,00

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Materials Testing

Characterization of bipolar plates, membrane materials, felt electrodes and electrolyte chemistry in cell test

columbic efficiency

energy efficiency

discharge power density

Development of commercial test rig for redox flow batteries with standardized test cell

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© Fraunhofer ICT

Materials (Bipolar plates)

Thermoplastic and thermoset bipolar plates Injection molded

Compression molded

Fillers Natural and synthetic graphite

Carbon nanotubes

Carbon fibers…

Coated metallic bipolar plates Substrates Fe, Ti, Al

Metal doped diamond-like carbon (Me-DLC) / boron doped diamond Dopants transition metals (IV-Vi)

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© Fraunhofer ICT

Stack Development and Production

600 cm² active area, 22 cells, 18 – 35 V

max. 60 A, 1,5 kW

Simple stack design

Simple assembly of stacks

Process technologies for flow frame production (injection molding)

Systems up to 30 kW

Design of demonstrators and test rigs

Systems for home PV

IPS systems with hybrid of Supercap bank + RFB

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Simulation & Modeling

Simulation of flow through of cells/

battery stacks

Electrochemical battery model 2D of

V-RFB/ VOFC

Electrochemical battery model 3D of

V-RFB under development

Evaluation via in-situ measurements

Segmented cell for the measurement

of local current densities

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© Fraunhofer ICT

System (Redox-Wind)

2 MW wind turbine with a 2 MW/ 20 MWh

All-Vanadium-Redox-Flow-Battery at the

ground of ICT

Junction / DC coupling of wind turbine and

battery

Development /adaption of the battery to the

wind turbine

Synergies with a new design of the electrical of

cost effective production technologies

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© Fraunhofer ICT

Energy Systems

Energy optimization

Analysis and optimization with respect to

Electricity, heating, and cooling requirements of the company + public areas

Utilization of surpluses

Integration of distributed generation and energy storage

Shifting of loads to reduce peak demand

Efficient use of energy

Visualization of energy flows

Integrated Optimization

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© Fraunhofer ICT

Increasing the self-supply for electricity and heat demand

Utilization of surpluses

Reduction of peak loads

Visualization of energy consumption and management of energy data

Specific savings goals only possible after analysis of potential

Simulation Analysis Definition of goals

Practical implementation

Energy Systems

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Energy optimization

Secure energy costs through distributed generation and energy storage

Transparency and understanding for own consumption

Keeping investment costs low by contracting models with public utilities

Savings through the use of energy surpluses

Reduction in procurement costs through peak load reduction

Load shift: The highest peak power in the load curve determines the amount of kWh price

Added value through networking activities

Energy Systems

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Design and simulation of a hybrid power supply for an observatory tower in Oman (desert) to 3000 m altitude:

Modeling with photovoltaics, small wind power, generator and battery (redox flow / lead-acid battery)

Simulation of one year operation term

Design of the components for a commercial operation

Energy Systems

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Energy Optimized Research Centre

Simulation ICT campus electrical supply by:

Wind turbine with redox flow battery, CHP and power grid

Simulation of future operational scenarios

Investigation of the degree of self-sufficiency

Extension of the model to the heat supply and an intelligent interaction of the components

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Materials• Electrocatalyst• Support material• Membrane electrode

assembly (MEA)• Bipolar plates

Characterization• Materials• Degradation• System tests

System• DAFC Systems up

to 5 kW• Reforming• Degradation, Aging• Simulation

Applied ElectrochemistryFuel Cells

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Development and Evaluation of Materials

Electrocatalyst

Alcohol oxidation in alkaline FCs Oxygen reduction in alkaline FCs (PGM free) Alcohol oxidation in HT-PEMFC Sulfur-containing reformat in HT-PEMFC PEM-Electrolysis

Support materials

PEMEL Anodes HT-PEMFC

Binder materials for alkaline membrane fuel cells

TEM image of electrocatalyst

SEM image of catalyst layer in electrode

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© Fraunhofer ICT

Fraunhofer ICT designed a flow through DEMS Cell

The quantification of CO2 production including in alkaline media

Determination of the alcohol oxidationproduct spectrum

Investigation of reactions for the electrochemical synthesis

Investigation of support and binder corrosion

HT-DEMS

Only at Fraunhofer ICT DEMS measurements in the gas phase at elevated

temperature Characterization of catalysts for HT-PEMFC under

realistic conditions

Development and Evaluation of Materials

HT-DEMS cell for the characterization ofcatalyst

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© Fraunhofer ICT

Development of membrane electrode assemblies (MEA)

LT-PEMFC HT-PEMFC AEMFC PEMEL

Development of adapted coating processes

Binder selection Ink formulation Spraying conditions Thermal treatment

Partially automated spray-coater for small series

Membrane Electrode Assemblies

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Single cell tests Current - Voltage Impedance spectroscopy Current density distribution measurement Determination of the electrochemically active surface Product analysis with online MS Offline analysis with GC or HPLC

Measuring stations LT-PEMFC/PEMEL HT-PEMFC DAFC

Investigation of mass transport in PEMFC electrodes for automotive applications

Analysis of transient corrosion processes by online mass spectrometry

0 50 100 150 200 250 300 350 400 450

0,2

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cell

pote

ntia

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current density / mA cm-2

Alkaline Anion Exchange Membrane Direct Ethanol Fuel Cell Performance

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Membrane Electrode Assemblies

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Stacks and System Integration

Direct alcohol fuel cell systems for portable applications

Fuel cell based range-extenders and APUs

HT-PEMFC petrol steam reformer as APU for electric vans

Reformed methanol fuel cells as range extender for compact class car

Hydrogen PEMFC range-extenders

Fuel cells for military applications

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© Fraunhofer ICT

THANK YOU FOR YOUR ATTENTION!

Dr. Duygu Karabelli

Tel.: +49 (721) 4640827Email: [email protected]

M.Sc. Burak Caglar

Tel.: +49 (721) 4640514Email: [email protected]

Applied ElectrochemistryFraunhofer-Institute for Chemical TechnologyJoseph-von-Fraunhofer-Str. 776327 Pfinztal

DEPARTMENT OF APPLIED ELECTROCHEMISTRY

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