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150W Portable Direct

Methanol Fuel CellPower Supply/Battery Charger

150W Portable Direct

Methanol Fuel CellPower Supply/Battery Charger

Lawrence J. Gestaut

Cecelia Cropley

Giner Electrochemical Systems, LLC

Newton, MA

2005 Joint Service Power Expo

Tampa, FL - May 4, 2005


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Why Fuel Cells?Why Fuel Cells?

Fuel cells can offer quiet operation, a

lower heat signature, fuel efficiency,

supporting communications, surveillance

and other electronic equipment.

- Fuel Cell Today, April 20, 2005


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Battery LogisticsBattery Logistics

Marines reported they were down to lessthan a 2-day supply of primary batteriesduring OIF combat operations.

CECOM officials said they weredeveloping newer, lighter-weight

rechargeable batteriesto reducedependence on disposable batteries.

US GAO Actions Needed to Improve the Availability of Critical Itemsduring Current and Future Operations, April 2005, pps. 90,95


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Battery LimitationsBattery Limitations

Portable power is critical, but

Batteries can not provideincreasing energy demands

Primary batteries are a logistic

and cost concernSecondary batteries require aportable and reliable charger


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What is a Direct

Methanol Fuel Cell?

What is a Direct

Methanol Fuel Cell?

CH3OH + H2O CO2 + 6H+ + 6e-

3/2 O2 + 6H+ + 6e- 3H2O

CH3OH + 3/2 O2 CO2 + 2H2O

No compressed hydrogen No reformer


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Applications

Applications

Small systems

20 W battery replacementsMid systems

150 to 500 W generators/chargers

Large systems

2 to 5 kW diesel generator replacements


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Types of DMFC

Small Systems

Types of DMFC

Small Systems

Natural air convection

Passive water management

Passive cooling

Low current density

>30% methanol possible

Generally planar cells


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Small

System

Small

System

Toshiba

12W/20W peak

Photo from Fuel Cell Today


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Types of DMFC

Mid & Large Systems

Types of DMFC

Mid & Large Systems

Discrete components

Forced air

Active water management

Active cooling

Moderate current density

Dilute methanol water mix


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Types of DMFC

Large Stacks & Systems

Types of DMFC

Large Stacks & Systems

800 W System

1.5 kW Stack


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GESApproach to DMFCGESApproach to DMFC

Bipolar stack, operating at high powerdensity

Neat methanol fuel, on-board dilution

Operate at 60-70C

Near-atmospheric air supplied by blower


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M

MeOH

Return

Cathode

Out

Air In

Drain

Air/Water

Separator

M

M

M

Condenser

MeOHCooler

M

Sump

Pump

MeOH+H2O

Mixing Tank

MeOH

Tank

Air

Pump

Air/Water

Separator

MeOH Inlet

DMFC Stack

Anolyte

Pump

DMFC SchematicDMFC SchematicDMFC SchematicDMFC Schematic


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Direct Methanol

Fuel Cell (DMFC)

Direct Methanol

Fuel Cell (DMFC)

6.8 kg

10 liters


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DMFC OperationDMFC Operation

Transportable

Rapid start

Load following

Low thermal

signature


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DMFC RefuelingDMFC Refueling

Liquid fuel Refuelable

on-the-fly


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Advantages of DMFCAdvantages of DMFCAdvantages of DMFCAdvantages of DMFC

High system energy density

Safe and easy transport

Long membrane lifetime

R

eactant humidification is not required


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Fuel Comparison

1500 W-hr (includes tank)

Fuel Comparison

1500 W-hr (includes tank)

Neat

CH3OH

2000 psig

cylinder

Metal

hydride

canister

Volume 1.5 liters 8.8 liters 4.5 liters

Weight 1.25 kg 13.2 kg

(80 g H2)

6.8 kg

Refillable by

User?

YES NO NO


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Disadvantages of DMFCDisadvantages of DMFC

Lower cell voltage and lower current

density

Larger stack, but light and compact

Fuel efficiency

Currently ~17%,

Forecast ~25%


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Fuel Cell Performance

Comparison

Fuel Cell Performance

Comparison


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Numbers and total weigtht of Li/SO2 batteries needed to generate the same electric energy equivalent to a DMFC system at120W rate (9A discharge). Li/SO2 battery: 1.027Kg, 176Wh. The data were obtained by Gainer 120W DMFC system.

0

10

20

30

40

50

60

70

0 20 40 60 80 100 120

Time (Hr)

Weight(Kg)

0

1020

30

40

50

60

70

80

90

100

NumberofLi/SO

2

bateries

Weight of all fuel,water and DMFC

Weight of allbatteries

Number of Battery

NeededWeight of fuel

I = 9A

PrimaryBatteries

Comparison

PrimaryBatteries

Comparison


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GES 150 W DMFCGES 150 W DMFC

6.8 kg

10 liter

3 hours operation

with stored fuel

Rapid start

Excellent load

following


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Future DevelopmentFuture Development

Reduce stack weight and volume by > 25%

Increase power density

Improve catalysis and structures

Improve mass transfer

R

educe methanol crossover Improved StackDesign

Lighter/thinner end and bipolar plates


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Improve reliability, durability and

ruggednessStore and operate over militarytemperature range

Reduce thermal and acoustic signaturesDecrease unit size and weight

SystemsEngineering

Issues

SystemsEngineering

Issues


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Projected MetricsProjected Metrics

Mass (kg) Volume (l)

150 W 3.2 6

500 W 11.3 20

1 kW 18.1 35


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ConclusionsConclusions150W DMFC provides >60% weightreduction compared to primary batteries

for 72-hour missions

DMFCs have many advantages includingease of fueling

DMFC could be fielded in the near term


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AcknowledgementsAcknowledgements

DARPA

Army Research Laboratory

Jet Propulsion Laboratory

Parker Hannifin