Fuel cell drive and high dynamic energy storage systems — Opportunities for the future city bus

Fuel cell drive and high dynamic energy storage systems - Opportunities for the fbture city bus By Dr.-Ing.

Karl Viktor

Schaller

and DipI.-Ing.

Christian

Gruber,

MAN

Nutzfahrzeuge

The future growth of metropolises will present new challenges for road-bounc transport. In view of the limited availability of fossil fuels and the necessity o reducing in the long term the output of emissions from the transport sector which impair the climate, the local public transport sector needs a more efficient environmentally compatible means of transport. For MAN hydrogen is the fue of the future, with a high implementation potential. Hydrogen can be used ir both internal combustion engines and in fuel cells. In urban deployment the fue cell drive has specific advantages, and is suitable for use in city buses. The integration of low-cost energy storage systems, such as supercapacitors, can helI to improve the fuel consumption and reduce initial system costs. In May 2OO( MAN unveiled a fuel cell bus, and will continue this development work wit1 further vehicles. The first deployment of pre-series bus fleets with fuel cells usirq hydrogen as their fuel can be expected from about 2005. The

world’s

metropolises

continuously,

and

considerably 2025

in the future.

two-thirds

be living

this

are

trend

In only

growing

more

than

accelerate

than

1 million

It is expected

of the world’s

in cities.

will

that by

population

15 years there

will will

be

Both

350 cities with

and

metropolitan

with

the

expected

areas will

for

unrestrictet

growth

lead to traffic

rates burden

effects Under

become

increasingly

produces

engine

with

the

past,

that

particulate

and

@ Limits

EEC 88i77

COP

10

14,4

12 NO,

[g/kWh]

gas -

oxides

(NOx),

monoxide

for trying

out

fuels and drive with

cleaning

internal

highly

systems

developed

will in the next few

significant

in Germany

relief with

“1 (Figure

regard

1).

commercial

vehicles,

stricter

- in particular

for NOx

and PMs -will

in 2005

These

(Euro

a predicted a fall

4) and 2008

increase

in the total subject

and

systems.

conventional engines

emission be

(Euro

5).

in the number

of

emissions

to limitation

of those from

the

sector is expected.[‘] new

technologies

together

with

catalytic

cars, will

reduce

transport

for particulate

and for NOx

No. 27

exhaust

carbon

reason

alternative

constituents

9

is

to limitation

nitrogen

(HCs)

exhaust-gas

transport 8

subject

(PM),

- was a main

Despite

7

concepts

of those

were

matter

hydrocarbons

vehicles,

6

drive

of the future.

reduction

constituents

introduced

5

vehicle

city/transit

Role of emissions in the past and in the future

For

3,5

gross

and inner

innovative

years lead to further

2

6 tonne

and

limits

Bulletin

from

up to the challenges

to emissions

Fuel Cells

for and

MAN

upwards

combustion

> 85 kW

compatible develops

Low-emission, Diesel

will

provide

areas.

facing

introducing

0-6

it to

the demand

buses,

(CO)

47

circumstances

to cope with

trucks (GVW)

on the

of life in urban

important

in urban

weight

systems,

environmentally

transport

transport

S

these

and

public

d oIf

on economic

and on the quality

efficient

of mor e

Germany

centres.

In desire

major

environment

people.I’]

the individual

mobility

a population

AG, Munich,

for

converters

the overall

by a factor

diesel

emissions

matter

engines,

for passenger from

by a factor

of 8 berween

road of 10,

1990 and

@

introduction 0

20

40

60

lkgllw km] 80 100 120 140 160 180 200 220 240 260 280 300

phase

hydrogen combustion

engines

combination CNG ICE, fNxa*rmany Methanol

ICE, Methanol

MAN

from NG

with

PEM FC, Ii2 from NG

and

fuel. in

an electric

is examining

of propulsion.

In vehicles internal

fuel

cells

and assessing

both

in internal

engines.l3,*1

Following

the development

of a city bus with

an engine running on liquid hydrogen, trials in regular service in Erlangen and

“2 ICE, H2 from biomass PEM FC, HZ from biomass

between

PEM FC, HZ from electrolysis

buses n bus operation

Ofual

production

1996 with

and

1998,

internal

These

buses are fueled

Since

they

apron

in the spring

offer

low-floor

engines

airport with

commenced

some 60,000

and its Munich

two further

combustion

gone into service at Munich

and distribution

forms

since 1996 that

can be used successfully

combustion

in

drive system.

It has been shown

hydrogen

PEM FC, H2-etectrotysis,Germa”y

for a new

can be used in conventional

duties of 1999

level

3).

gaseous hydrogen. on the airporr

they

have covered

km each, and have shown

a high

have

(Figure

of availability

chat they

for

the

bus

operator.

MAN’s first low-floor bus with fuel cell propulsion The

MAN

fuel

May

2000,

and contains

fuel

cell

along

cell

vehicie

bus represents

a further

The

bus equipped

context

with

with

project

PEM

Siemens

of the Bavarian

This

Environment

and the German

Agency

consider

limited

emissions

is no political towards

zero-emission

Figure mobility,

5. There

of energy

in the European

Union

(ZEVs),

mandate.

high

experience hydrogen

potential

benefits.

road

emissions with

without

by electrolysis

fuels.

is the fuel of the future, long-term using

or from

fossil

with

biomass

must be expected.

a Iower

was

carbon

fuel,

to a global

are

of methods

available.

predominantly fossil

resources

resources

oil. When

linked

Production

processes

which

that has a

electrolysis

is also

sector

from

environmentally

minor possible

69

if fossil fuels

reduction

are used, then

in the output

for commercial

vehicle

of CO, operations

only will

a be

(see

depend

of water

renewable

generation

compatible. However,

of achieving

The floor

make

a

in CO

2

small, is

decentralised an

important

zl

industry

fron

with

sources both

the

drive

I>

of th

e

in large

electrolyser advantage

system5

over

to

with

the model engine

fuel cell system

designation

has been replaced built

by Siemens

of four fuel cell modules

lowNL by a KWU.

connected

i.

;

CO,-fre

e

2). Hydrogen plants facilities, during

:

o

produce,

nearly

(Figure

for the move

of and in

n

sources

use biomass

electricity offer

in traffic,

sources of energy.

diesel

consists

the

reduction

gas ant cl

on the efficiencies

of hydrogen

can be produced

n

and with

fuel cell bus is based on a modern, vehicle

263. The PEM

technologies,

to prepare

and

development

and noise emissions term

State

Transport

a considerable

clean, renewable

hydrogen

to fossil energy

the way

transport

of new drive

is produce<

as natural

dependence

and

reductions

such

and

future

reduction

for the chemical

energy

heavy

in combination

oil,13] and points

can

hydrogen

processes

a worldwide

introduction exhaust-gas

of producing

Today,

production

long-term

S

aim

the

Ludwig-

Bavarian

Affairs,

supports

th e

point

for Economic

in the

Initiative. by

The

Technology

This

CO,

towards

content

hydrogen

with innovative vehicle drive systems opens up opportumttes for reducing the transport sector’s on crude

Source

fuel cell drive

and Linde,

coordinated

;>

for this problem.

contribution

A number

a

for producing energy

countries

emissions.

For

and environmental

prospects

threshold

Ministry

Hydrogen - a source of energy with a future major

has gathered

alternative

in

fo r

demand

the long

EU sees

including

MAN

with

for realisation

The

hydrogen

CO,

As a carbon-free

In the last few decades

growing

similar

The

transportation.

MAN

the

way to a solution

has to be considered

of the economy,

With particularly

Euro

as the key factor which

extensive

2).

higher

vehicles ZEV

the

of Euro-Stage-

will be met with

movement

in all sectors

of

Environmental

that the problem

to the Californian CO,

Ministry

economy

Hydrogen

Bolkow-Systemtechnik.15] German

milestone

4).

was developed

The

in

fuel cell. This

the road to the hydrogen-based

(Figure

2015.

was unveiled

a PEM

n

and

in

whicl th

h: e

Fuel Cells Bulletin No. 27

with

the transport

authorities

Nuremberg

in autumn

hydrogen

filling

in Erlangen

2000.

Linde

station

at

will

the

and

set up a

operators’

energy city

facilities.

density,

requirements in

buses

with

limited

fleets

offer

sufficient

storage

Fuel cell drive - efficient propulsion for city buses The

fuel cell, with

its high specific

the

partial

range,

internal

load

combustion

(Figure

7),

which can in series (Figure

with

a total

of 640

5), and the peripheral

The

power

current current,

be used

mechanically

motors

central

low-cost

drive

available buses,

and

and low-noise

demonstrates

from

On board

This

each with

a capacity of

system

the

consists

of 172

storage

liner

a full

carbon-fibre

system

capacity

and is mounted natural-gas

The

250 km per tank

and

Integration

CNG

permits and

proven

compressed

hydrogen

storage

pressure

system

relies mainly with

from operation

the safety of this

system

reducelvalves fitter

components

down,

the

winding.

The of 250

in a similar

litres

FC exhaust(air/water)

50

overall

S~emenselectnc

MAN diesel

DI

FC + LH2

MAN diesel

DI

FC + LH?

efficiency

II PI

manner

corresponds

4.

in

100 litres

for cooling

of

the fuel cell,

for the power

provided

supplying

as the steering the passenger conditions

No. 27

electronics

Additional

are

units

the auxiliary and brake

systems

are

systems, and for city bus

compartment.

of the new drive

Bulletin

the

a range of approximately

on the roof.

for

as

To keep

were

system

under

scheduled

quasito begin

160 kW

long haul

truck, 300 kW

on

special

authorities.

been problem-free.

air compressor

and

in other

technology,

buses, on the roof of the

also mounted

Fuel Cells

is the lower

The storage

series production tests

already

fill.

and the converters

Trials

main

applications.

systems

of having storage

by MAN

pressure

to approximately

diesel fuel, and permits

practical

storage

The

drive

position

hydrogen

the

of 1548

28 kg of hydrogen

of energy

heating

of hydrogen

but at much

compressed

drive

of an aluminium

has a maximum

psi) for a total

of hydrogen,

such

ICE, system.

of nine tanks,

system

are made

Other

had the favourable

developed

system

is stored

litres.

tanks

terms

the diesel the drive

be at the

because of the nonbase.

units.

developed

pressurised

vehicle.

for

of methanol,

would

supplier

of

show a wide

450-600

the hydrogen

gas in a system

to standard

costs

storage

solutions,

automotive

MAN

worldwide

drive

electrical

6) and auxiliary

Technology.

bar (3500

higher

range of technical existent

electric efficiency

same level as with

in existence

fuel cell buses have design. The handful

of

the fuel cell for powering

the vehicle

a compressed

with

tank-to-wheel

a common

necessary

have approximately

drive system (Figure

storage

in

operated hydrogen

comfortable

In the vehicle the bus’s standard

weight

use of

efficiency

use of

The

ranges

direct

for

propulsion.

and the DC network V available

the

the

the range

buses.

the operating

cell, energy

radius

space

concept

makes

from

for MAN

system guarantees

drive

The

unit

components

fuel

cruising

linked

gearbox

rear axle directly.

the

they

volume low-floor

Experiences during design and integration of the Siemens fuel cell system prototypes

via

before

higher

However,

Just like the first automobiles,

hydrocarbons, of CO

to

on the roof.

not yet reached to hydrogen

maximum

In the case of onboard

direct

the fuel cell to alternating the output for the electric

asynchronous

of the electric

for city

the

energy

the fuel cell system.

system.

convert

via a summation

series-production

modules

cells

operation

operation.

and cleaned

in

offers

in over

reduces

to be converted

systems

disadvantage

drive system. Two Siemens

proven,

supply

electronics

output from and regulate

individual

in urban

to fuels containing

have

hydrogen

efficiencies

advantages

effectively

in vehicle

Compared reformer

engines

and

consumption

has

leading

in the vehicle.

I

has

LH&orage

High dynamic energy storage in supercapacitors

Linde

OP eration environments

of

road

of acceleration with

of the drive

cycles.

deployment,

can be achieved energy

electricity

like a generator,

efficiencies.

During

vehicles

produce

driven

and this energy

used for the next moving-off There storage

concepts,

hopes The

electric

converters

drive

already

trolley-

system

uses motors

developed

and hybrid

and

for diesel-electric,

drives.

With

minor

changes

this technology was readily operational. For the fuel cell system test and integration, standard

rear-end

space-frame

used, prepared with all modifications incorporated Siemens

integrated

a number system

and

bus drive.

system

modifications.

After

the interfaces using 3D-CAD.

tests with

an electric

electric

of the bus was

the system

of bench

under

the system

and performed simulating

stable

long-term

off by Siemens

the hardware successful.

preliminary

testing

During phase

were

prototype’s

the start-up

out. After bus

solving

fulfil

specific

down

costs

a

and

and

requirements.

increase

is in prepararion

bus with (Figure

have a fuel cell system of 120 kW. Air

This

Liquide.

To bring the

Nora) The liquid

v.9

in Italy will supply fuel used will hydrogen

system

an electrical

is being

Fuel

vehicle

Cells

by short

This

of

Thi

S

with

concept of

the

and

energy

or hybrid

systems.

The

for high-dynamic

storage

charge

in

storage

These

high

an obstacle

to

makes

so-called

capacitors

offer

the

advantages:

High

l

1

phase wit1 1

the fuel cell drive

as an optior 1

power

density

low-loss

and low-noise

electrical

energy.

l

Reliable,

maintenance-free

l

Modular

design,

installation

set-ups

High

l

and sufficient

density.

Dynamic,

l

co the drivl

demonstration

specific

energy

t

an electrica

be added

drive

‘supercapacitors’.

wil 1

and Copenhagen

system,

a second

i

One use

following

of 2001.

will

1

ant

of deploymen

system

vehicle

introduction.

periods

storage

commercial market

quarter

energy

power

their

a nine

BVG.

in Lisbon

because

in battery

these are not

are too low for single-mode

liquic i

on the routes

authority,

in the third

MAN

views

points

will output

the

way

to the

to establish especially the

itself

in urban

case

of

drive

systems

alternative against

the diesel

diesel

engines

US$SO-100

developed

by De

storage

of

operation.

allowing

for

various

in the vehicle.

cost-reduction

potential.

The

for the bus will,

for the

(Figure city

onwards

will

for city

about

US$200

for natural

status,

and

installation

conventional on when

not only

that is acceptable

bus drivl e

The actual

are on tht e

extent

diesel,

In normal

ant i

with

systems

to the market.

to their

compared acceptance reach

S

fev v

resulting

in

sizee

consumption.

wit1 1

Apart

wil 1

consumption,

but also3 a cost leve ,l

effect

from

co a large

around

public transport, fuel consumption

larger the

capacitors

on driving

energy

by

energy by up to controlled

recovery,

reductions

thus in

fuel

saving

in

can have

a favourable

dynamics.

The

for moving

off can be added

system.

hybrid

drive

town.

encountered

in bus lanes permits even

2000 trials.

depends profile

as is often

maximum

from

The

in a diesel-

autumn

to thorough

recovery

city traffic,

Operation

Market

gas system

energy

on the deployment

15%.

regard

Matsushita commenced

be installed

be subjected

braking

with

has

and

viewpoint, fuel ccl 1 reached an advancec rl

on the infrastructure,

these drive

arounc ;,

in the next

MAN

9) will

system).

and will

components

Siemens

bus,

road vehicles for recovery can reduce

space

engines.

for

electronic

(formerly

development of high-power capacitors that are al 1 : to be used initially in city buses. A first prototype

for trucl

to

the

Components),

system

per kW

the fuel storage

EPCOS

electric

gearboxes

From the technological drive systems have now

with

company

costs

amount Those

Together

to be measure< i

of US$120-150

depend

hydrogen.

The

today

per kW

drivf e

vehicles,

have

automatic

th,

applications.

order

development

with

as a vehicle

engine.

years offer no drawbacks

(formerly

future,

commercial

per kW. with

(including

the stacks.[‘l

be liquid

transit

on routes

systems

fuel cell drive

8). This

with

system

Nuvera

PEM

in Berlin

that

and cost also constituted

(such a S

ones. High

placed

it has proven

weight

range).

phase of the project

system,

MAN’s second-generation fuel cell bus low-floor

(operating

suitable

mechanical

but also electrical

in the past been but

this recovered

not only

r

on the technica the vehicle

In the second

of and

to

or

is soon to pass through

be followed

potential

do not

reliability

inpu t

the infrastructure

requirements

Berlin

In

a lot of components

automotive

for installation),

the

and testing work. above,

depend around

density

Whethe

hydrogen

trial operation

that

still needs a great deal of development.

A second

prevailing

very

bar.

ti

have

concepts,

storagl e

energy

hydrogen.

rht e

has examined

the bus operators.

(EMC)-

finishing,

are industry-standard,

customer

and

‘roll out’ was after just three months

As mentioned

is used will

conditions

planned

system

compatibility and

integration

auxiliaries

hydrogen

will

and MAN

additional

carried

problems

intensive

(pressurised)

vehicle

at 250

is the higher of liquid

gaseous

commence

facility,

in the bus was almost

ofelectromagnetic

related

disadvantage

half

pressurised

hydrogen

gaseous

in the production

month

less than

of the

current

This

of

need

weight

for

the

full load at the Siemens

immediately

number

and

content,

system

the

was signed

modifications

space

customer

for this trial application. Integrating

energy

volume

cooling

tests led to a number

demonstrating

operation

and

an external

load

These

a

same

can be

cycle.

are several ways of storing MAN

fuel part

and by operating

at high

electrically

energy.

In contrast

here by recovering

coasting

swnmatlon gea ho* 2 x 75 kW,,,

urban

noticeable

expended

the fuel cell system

in

by a large number

and braking

long-haul

savings

vehicles

is characterised

power

from

system

Fuel Cells

energy needed

the storage

does not have

Bulletin

No. 27

and will

make

they reduce MAN

a market

regards

period

launch

easier

the costs for the overall

before

five

to ten years

series production

fuel cell drives

because

system. as a realistic

of city buses with

can begin.

References 1. I? Hall,

U. Pfeiffer:

future

21. Urban

urban

future,

Berlin,

2. U. Hopfner: und

moving

to provide

off in such

costs. MAN

will

combination

the full

cases, and this

be examining

with

later

phase of the project, fuel cell bus will

for

and

reduces

the

passengers,

and will

in

preparations

for the market

in a

precondition

hybridisation

a fuel cell drive

MAN

power

system

in which go into

the second

service

with

drive

systems

for

technological a

bus operator.

series

storage

of fuel cell hydrogen will

buses in local public

secure the acceptance

of new fuels

Only

reductions, energy

Electric

Industrial,

Japan This

miniaturised

the transfer

fuel cell assembly

of waste

hydrogen

storage

heat from

unit,

invention

membranes

fuel cell

Matsushita

Foster-Miller,

facilitates

the cell to the

polymers,

Patent

number:

unit.

Composite

1

Applicant:

WO

bipolar

This

Stack compression Power

Systems, a compression

which

can be used over a wide

range

without

imposing

stack fluid number:

Canada assembly

spring

deflection

limitarions

on

the

bipolar

or

mixture

graphite

powder.

electrically

WO

of

resin

a

and

hydrogen

city

und Technik

fuel cell Japan

includes

between

oxidiser

the exchange

reacted

with

below

0°C.

Patent

number:

from

and mixing

a medium WO

of heat and

and unreacted

of moisture

gas exhaust,

gases,

the fuel gas or of the separated

with

a melting

point

00125379

The invention ionically

USA

relates to novel inorganic-organic membranes

conducting

Patent

strong,

mass-produced

membrane

Lynntech,

composite

is inexpensive,

lightweight,

easily

impermeable

Patent number:

consists ester

material

conductive,

corrosion-resistant, relatively

pressures.

US 6057053

system

Applicant:

plate

of a vinyl The

first

Verkehr

454.

Composite

USA

Laboratory)

separator

moulded

report

plate

of California,

National

VDI

Germany’s

the separation

copolymers,

propulsion

buses.

1998.

Toshiba,

moisture

00124736

University

(Los Alamos

Patent

This

polyphenyl-

including

of

For more information, contact: Dr.-lng. Karl Viktor Schaller, Engineering Advanced Development, MAN Nutzfahrzeuge AG, Dachauer Strasse 667, D-80995 Mijnchen, Germany. Tel: +49 89 1580 2057, Fax: +49 89 1580 3228, Email: Karl-Viktor-SchallerQmn.man.de

moisture

number:

internal

sulfonated

Hydrogen

apron

Solid polymer

and so can be used for

US 605705

October

Applicant:

blends.

than a conventional

This stack incorporates

materials

polyarylether-

sulfone

Patent

Ballard

reduce

based on sulfonated

on behalf

6. http:/lwww.euweb.de/fuel-cell-bus in

operation,

ion-conducting

or

1418,

E. Hipp: airport

10 (1997)

to novel

polymers

for

5. http://www.brennstoffiellenbus.de

USA

relates

ketone

longer

Applicant:

will

vehicle

system

cells,

be satisfied,

during

report

bus, one year in operation,

can the requirements

such as supercapacitors,

Strailengtiterverkehrs

Institute,

drive

fuel electric

introduction

consumption

Applicant: This

Applicant:

in

July 2000.

July 1999.

4. D. Riechers:

is further

and

in this way

role in

The essential

production

Novel ion-conducting

Patents Miniaturised

launch.

and

particular those relating to costs. Energy storage systems with the potential for significant cost

Prospects Trials

an important

systems

for a broad-based

transport

play

operators

developments

hydrogen systems.

among

urban on the

der Fahrleistungen

des

IFEU

report,

conference

Germany,

Emissionen

3. C. Gruber, to be designed

world

Entwicklung

1990-2015. VDA,

The

21, Global

number:

especially membranes

useful

as

in fuel cells.

US 6059943

and

to hydrogen.

PEM fuel cell electrode

00125372

Applicant:

Matsushita

Electric

Industrial,

Japan Improved Applicant: This

improved

exchange resilient

Patent

Power

MEA

membrane

Systems,

comprises

a sealing

layers in the sealing number:

US 6057054

Fuel Cells Bulletin No. 27

coextensive

integral material

Applicant:

Canada

and electrode

fluid-impermeable

impregnating electrode

Membrane

MEA Ballard

layers

ion-

(Los Alamos

and a

In this PEM

seal made by

into the porous regions.

hydrophobic with

National

number:

WO

metal

directly 00125377

side comprises

backing

and with

a

in contact

hydrophilic

IO the membrane.

a PEM

preparing

USA

Laboratory)

gas diffusion water

Here

of California,

fuel cell the anode

the membrane

for providing Patent

humidification

University

areas

l-400 colloid. onto

fuel cell electrode

a liquid

mixture

catalyst-supporting nm

particle

The

electrolyte

is produced

containing carbon

size

powder

PEM

surface,

number:

US 6060187

giving

and a

electrolyte

is effectively

the catalyst

by

a noble

a wide

adsorbed reaction

area. Patent

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