AVL Fuel Cell Engineering 1

AVL SOFC APU (Auxiliary Power Unit)

Portable power out of diesel fuel without noise and emissions!

Other markets:

Camping/leisure

MarineMilitary

Design Targets:

� 3kW electrical power

� 10kW thermal power

� el. efficiency ~35%

� Fuel: road diesel (< 15 ppm S)

� 80L, 75kg

� ~ 55dB(A) noise

� 8000h lifetime

� 300/3000 cold/warm cycles

Remote & back up power

HD Truck Anti-Idling

AVL SOFC CHP System for decentralized Energy Supply

System features:

�Fuel: Natural Gas

�Total electrical efficiency 50%-60%el (AC)

� >90% total efficiency

�Hot gas anode recirculation (>600°C)

�Production cost target <2000€/kW

Stand alone 10kW module as building

block for commercial 20-100kW SOFC

CHP Systems

AVL tasks:

�System design and layout

�BoP components (media supply, reformer, burner,…)

�Controls

�System integration, build-up and operation

AVL Fuel Cell Engineering 3

SOFC Engineering

� system design, simulation, development and build-up1

� component development

� reliability/durability engineering

� testing (from cells to large stacks)

� simulation (from CFD/FE on cell level2 to complete systems)

� specification development

� media supply (compressors, blowers)3

� fuel processing (reforming & desulfurization)

� control

� consulting

� small series manufacturing

(1)

(2)

(3)

AVL Fuel Cell Engineering 4

Background for Stack Diagnostics

Usually critical operating status is monitored by measuring the cell

voltages individually. Large stacks thus require costly

instrumentation and elaborated wiring layouts.

Cost efficient solutions with less complexity are required.

AVL Approach THDA

� On-line detection of critical FC operating conditions w/o

measuring individual cell voltages

� Analysis of the effects of voltage drops instead of measuring

voltage drops itself

� THDA technology analysis change in the harmonic distortion

content of a superimposed signal

Customer Benefits

� Instrumentation effort is relatively small and of low complexity

� 2 channel measurement � cost effective (no cell voltage

measurement required)

� New extended functions enables identification of different

causes for critical conditions e.g.

water flooding / membrane drying / cathode- or anode effect

PEMFC Cell and Stack Diagnostics

AVL Fuel Cell Engineering 5

CFD Analysis of PEMFC Cells and Components

Background - Fuel Cell Performance Optimisation

Critical part load operating conditions of fuel cells lead to corrosion

effects and reduction of stack life time. Many effects are related to

problems with water management. Performance optimisation

therefore requires the identification of the problem(s) and their

elimination by modification of cell design, material properties and

operational parameters.

AVL Approach - Simulation

� Consideration of electrochemical effects, heat transfer and

water balance (generation-condensation-evaporation-

transport) in MEA

� Modelling of critical gas permeation effects

� Full 3D treatment of 2 phase flow in porous material and

open channels

Customer Benefits

� Validated models with flexibility for different membrane and

electrode types

� Experienced engineers for assessment and optimisation

� Standard procedures for meshing (AVL-FAME)

� Applications for industrial & research projects since several

years

Flow channelFlow channel

Gas diffusion layer

Reaction layerReaction layer

MembraneMembrane

Region

3D

1D

1D or 3D

Momentum & pressure

Enthalpy

Phase mass

Species mass

Solved quantities

See above

Sources

Interfacial momentum

Interfacial heat

Interfacial mass

Species diffusion

See above

+ Darcy friction

+ Capillary force

Electrode potential

Current density

Membrane potential

Water flux

Crossover fluxes

Species mass fluxes

Enthalpy fluxes

Temperature

Pressure

Species concentra-tions

AVL Fuel Cell Engineering 6

Objectives

Air & gas management of PEMFC systems

Tasks

� Customer specific design, development andprototype manufacturing

� Radial-blower technology

� Total net electric efficiency >50%, low noise

References

� >10 blowers developed for fuel cell systems

� Air supply (ambient- and pressurized systems)

� Anode recirculation

Services

� Customer specific blower development

� Production of prototype blowers and small series production

Component Development: Air and Gas Management System

Blowers for SOFC system

Automotive PEM compressor (18kW, >2.5bar)

AVL Fuel Cell Engineering 7

System Validation

Safety & reliability

• Failure mode identification (FMEA & FP-analysis)

• Definition of suitable target values and end-of life criteria

• Definition of detection & counter measures

• Identification of safety standards

Verification & validation

• DVP (Design verification & validation plan, organisation & timing of test activities)

• Setup of functional test programs (Identification of standardised test procedures, test procedure definition for non-standardised tests)

• Load matrix (Setup of reliability test programs, test cycle definition for long-term tests, determination of acceleration factors, optimisation of demonstrable reliability, test times & costs)

• Monitoring & support of tests (test results, open topics, adaption of test cycles, …)

• Evaluation of test programs (final evaluation of test results and system status, points of improvement, …)

AVL Fuel Cell Engineering 8

Fuel Cell Testing

Testing and Validation

• System Tests

• Failure mode specific durability tests

• Sub-system and component Tests

• Component preparation for testing

• Test result analysis

Specific test services

• Functional Tests (Thermal and Vibration Analysis)

• Rig-Tests

• Shaker Tests

• Hydropuls Tests

• Climate Chamber Tests

• Corrosion Tests

• Vehicle Tests

• Acoustic Test