automotive stack: specifications, prototype and first … · automotive stack: specifications,...

Hannover-Messe 2012

25.04. 2012, Technical Forum

Dr. Joachim Scholta, Dr. Ludwig Jörissen, Prof. Dr. Werner Tillmetz

Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW)

Automotive Stack: Specifications, Prototype and First Test Results

(An Example of Services Provided by ZSW)

- 1 -

Stuttgart:Photovoltaics Division,Energy Policy and Energy CarriersCentral Office

Widderstall: Outdoor Test Facility

Ulm: Electrochemical Energy Technologies Division

ZSW Locations

- 2 -

Electrochemical Energy Technologies

Main Building, Helmholtzstraße 8 eLaB, Lise-Meitner Straße 24

• Development of batteries and fuel cells- Synthesis and characterization of active materials- Modeling and simulation- Optimization of components and systems- Testing, evaluation and qualification

• Scientific and industry co-operations

- 3 -

Electrochemical Energy Technologies (EC)

Departments

AccumulatorsMaterials Research

(ECM)

Accumulators(ECA)

Fuel Cell Fundamentals

(ECG)

Fuel CellStacks(ECB)

Fuel CellSystems

(ECS)

- 4 -

Optimization of Fuel Cells

Methanol concentration distribution

Monte-Carlo simulation of the water distribution

Ageing (75% PTFE) Ageing (65% PTFE)

• Modeling of cell design and flow field • Investigating ageing processes• Simulation

- Water management (MC, VOF)

- Concentration distribution- Gas velocity distribution- Temperature distribution- Pressure loss- Current density distribution

(CFD, FLUENT®)

- 5 -

Characterization of Fuel Cell Components

• Bipolar plates, flow field, gas diffusion layers (GDLs),membrane-electrode-assemblies (MEAs)

• 3D visualization (µ-CT)• Proof of specification• Mechanical parameters• Hydrophobicity and further surface characteristics (SEA, Hg-Por.)

Flow field digitalization 3D digitalization for components characterization

GDL structure patternfrom µ-CT

- 6 -

Visualization of Water Distribution

Synchrotron tomography:3D imageof a fuel cell

Neutron radiography:water distribution in gas channels

H2-Einlass Luft-Einlass

H2-AuslassLuft-Ausla

ss

mm

• Synchrotron radiography and tomography- Visualization during real operation- Analysis of 3D water distribution with up to 10 µm resolution

• Neutron radiography and tomography- Visualization of water removal out of gas channels- Measurements of fuel cell stacks up to 400 cm² cell area

- 7 -

Fuel Cell Technologies and Manufacturing Techniques

CAD drawing of a 100 cm² fuel cell stack

Sealing and adhesion technology

• CAD design, FEM analysis, assembly and acceptance testing • Power range from 50 Wel bis 100 kWel

• Sealing and adhesion technology• Investigation of manufacturing techniques• Robot based stack assembly• Durability testing (continuous operation for 20,000 hours)• Experience with more than 700 Stacks

Automotive fuel cell stack

- 8 -

Different Applications Require Different Stacks

100 cm² high power 560 cm² high efficiency 130 cm² low pressure drop

100 cm² basic 100 cm2 improved cooling 200 cm² basic

- 9 -

PEFC Stack Development is an Interactive process

ZSW is offering the following services to industry Definition of stack specifications based on customer requirements Development of stack concept based on application requirements Surveys of scientific and patent literature Development of sealing concepts Development of manufacturing / assembly concepts Qualification testing of components Flow and thermal modeling taking electrochemical processes and

porous media into account Design engineering of bipolar plates, end-plates, current collectors

... Prototyping Stack functional- and qualification testing Concept validation using imaging methods

- 10 -

Service: Stack Specification Based on ApplicationRequirements

Design of a Stack for Automotive Applications as an Example

Stack design appropriate for automotive requirements and operating conditions

Specifications worked out in the FCH-JU Autostack project (FCH-JU GA 245142):

Priority 1: Power density (kW/l) – target > 2kW/l Priority 2: Specific power (kW/kg) – target > 2kW/kg Nominal load (typical): 80 kW Area specific power density: 1W/cm² Single cell voltage target: 670mV Stack design

300 cm² active area 300 cells

Challenge: Reduction of cell pitch

- 11 -

Service: Component Qualification

Example: Autostack pre-study usingexisting design (100 cm² activearea)

Proven manufacturing of up to 90 cells

Negligible scaling effects

Operation with hydrogenor reformate

Low pressure drop (customizeddesigns available)

New compact design with lowpressure difference and high min/max load ratio

0.50

0.55

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1.00

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I [A/cm²]

UEZ

[V]

0.00

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P [W

/cm

²], p

ein

[bar

]

UEZquer [V]UEZmin [V]UEZmax [V]P el [Watt/Zelle]p diff_An [bar]p diff_Ka [bar]

Operating parameters: 10 cell stackTStack 60°CAnode: pure H2, u 80%, DPT = 50°CCathode: Air, u 40%, DPT = 55°Cmin gas flow äquivalent 5A

- 12 -

Service Example: Component QualificationCurrent Voltage Curves (H2/air) - Autostack Development Pre Study

Current density above > 1.6 A/cm² @ 600 mV (> 2.0 A/cm² @ 500 mV) Power density above 1.0 W/cm² (@ 500 mV)

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1.0

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current density [A /cm ²]

U s

ingl

e ce

ll (a

v.) [

V]

am bient, anode: dry, cathode: dp 50 °Cam bient, anode: dp 50 °C , cathode: dp 50 °C1 bar, anode: dry, cathode: dp 50 °C1 bar, anode: dp 50 °C , cathode: dp 50 °C2 bar, anode: dp 50 °C , cathode: dp 50 °C2 bar, anode: dry, cathode: dp 50 °C

10 cell s tack, Active area= 100cm ², coflowH 2/a ir operationO perating param eters: H 2: 70% utilization (above 0.5 A /cm ²)A ir: 40 % utiliza tionTstack: 65°C (coolant in le t)

- 13 -

Service: Manufacturing and Assembly Concepts

Tools for hydrogen/reformate and ambient/pressurized operation 48-cell-stack qualified Cost efficient manufacturability in higher quantities possible

60-cell-stack 10-cell-stack 48-cell-stack (2007, machined BP) (2010, stamped BP) (2011, stamped BP)

- 14 -

Targets for Automotive Application

Developmental target:

Stack design appropriate for automotive requirements and operating conditions

Specifications from FCH-JU Autostack project:

Priority 1: Power density (kW/l) – target > 2kW/l Priority 2: Specific power (kW/kg) – target > 2kW/kg Nominal load (typical): 80 kW Area specific power density: 1W/cm² Single cell voltage target: 670mV Stack design

300 cm² active area 300 cells

Challenge: Reduction of cell pitch

- 15 -

Service: Modelling of Anode Flowfield-Velocity distribution-

Boundary conditions- 300 cm² active area - operating pressure 2 barg- Current density 1,5 A/cm² - utilization 80%- Stack temperatur 80°C - constant c.d. distribution- Dew point 60°C

Vel

ocity

[m/s

ec]

Optimization of media distributors Adequately even media flow distribution

Autostack Development

- 16 -


Rel

ativ

e Fe

ucht

e [%

]


Service: Modelling of Anode Flowfield-Humidity Distribution-Autostack Development

- 17 -


Pre

ssur

ele

vel[

Pa]

Optimization of media distributors

Service: Modelling of Cathode Flowfield-Pressure distribution-Autostack Development

- 18 -

Service: Modelling of Cathode Flowfield-O2 concentration distribution-


Mol

e fra

ctio

n[O

2]



- 19 -

Service: Stack Design Engineering

- Reduced cell pitch (2.65 mm)- Integrated tension balancing- Integrated shielding and tensioning concept- high area specific and volumetric power density


- 20 -

Service: Stack Prototyping

4 cells, commercial membranes and GDLsEnd plates from epoxy fibre plates


- 21 -

Service: Stack Functional Testing

Data close to automotive targetsPower density 1 W/cm @ 600 mV Power density 3,8 W/cm³ and 1,7 W/kg (active part of stack).

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Stromdichte [A/cm²]

Einz

elze

llspa

nnun

g [V

]

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spez

. Lei

stun

g [W

/cm

²]

Zellspannung bei UmgebungsdruckZellspannung bei 1 bar EingangsdruckZellspannung bei 2 bar EingangsdruckZell-Leistung bei UmgebungsdruckZell-Leistung bei 1 bar EingangsdruckZell-Leistung bei 2 bar Eingangsdruck

Betriebsbedingungen: 5 Zell-StackAnode: H2; 70-80 % Umsatz, TP = 55°CKathode: Luft, 45-50 % Umsatz, TP = 60°CTStack = 65-75°C Aktivfläche = 300 cm²


- 22 -

„Automotive Stack“ as an Example of Services Providedby ZSW to Assist YOUR Stack Development

• Proof of concept successful

• Data close to automotive targets

• Power density 1 W/cm @ 600 mV

• Power density 3,8 kW/l and 1,7 kW/kg (active part of stack).

• Stack design available as platform for test and development

- 23 -

Stuttgart:Photovoltaics Division,Energy Policy and Energy Carriers, Central Office

Ulm: Electrochemical Energy Technologies Division, Main Building

Ulm:Laboratory for Battery Technologies (eLaB)

Thank you for your attention!

Please visit us at booth D50.

Widderstall:Outdoor Test Facility

// Energy with a future

// Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW)

- 24 -

Part

ners

- 25 -- 25 -

• 20 fully automated test benches • 8 separate test cabins• Automotive system test platform• Cold chambers• 24/7 durability testing with a power range

from 100 Wel up to 100 kWel

• Hydrogen, synthetic reformate,Oxygen, air, synthetic air

• 700 m² test and laboratory space

- 25 -

Fuel Cell Test Centre

Stack test

Closed test cabin

- 26 -- 26 -

• Low and high temperature PEM Fuel cell stacks• Tests of fuel cell systems and system components• Hardware in the Loop tests• Automotive tests• Adjustable control system and test configuration• Automated data analysis• Failure analysis

Fuel Cell Testing

- 27 -- 27 -- 27 -

• Design and development of fuel cell systems - 100 Wel - 100 kWel- Automotive systems- Portable systems- Off-grid and Uninterruptible Power

Supply (UPS) - Residential power supply

and CHP systems• Prototype construction• Operating strategies• System simulations• System analysis

H2-Airport-Scooter 4 kW KWK System

Fuel Cell Systems

automotive stack: specifications, prototype and first … · automotive stack: specifications,...

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