Download - Hydrogen Utilization - Fuel Cell

MEMS Labs MEM Departmemt NSYSU

MEM Department NSYSU

Hydrogen Utilization - Fuel Cell

Shou-Shing HsiehDepartment of Mechanical and Electro-Mechanical Engineering

National Sun Yat-Sen UniversityKaohsiung,Taiwan

November 18, 2009



Items• What is energy ？ • Kyoto Protocol• Hydrogen Energy• Fuel Cell• Types of Fuel Cell• Micro Fuel Cell• Experimental Results• Fuel Cell Stack Design• Micro Fuel Cell Stack Design• Bipolar Plate Fabrication• Experimental Results• Conclusions• References

S.S. Hsiehppt. 01



What is energy ?

S.S. Hsiehppt. 02

The capacity for doing work as measured by the capability of doing work (potential energy) or the conversion of this capability to motion (kinetic energy).

Most of the world's convertible energy comes from fossil fuels that are burned to produce heat that is then used as a transfer medium to mechanical orother means in order to accomplish tasks.



• Fuel cells (Hydrogen Energy)

• Coal

• Oil & Natural Gas

• Nuclear

• Geothermal

• Solar energy

• Hydro power

• Wind power

• Biomass

Types of Energy

S.S. Hsiehppt. 03



Energy Crisis

S.S. Hsiehppt. 04

If we continue to consume energy on such a scale, we may face a petroleum shortage in the latter half of the 21st century, according to some predictions. Though nobody is certain how much petroleum is left

Because people used a large number of the fossil fuel, discharge the carbon dioxide in a large amount. These then cause global warming and, consequently

, one thing is certain - at some point we will run out.

, influence the human ecology.



Kyoto Protocol

S.S. Hsiehppt. 05

The Kyoto Protocol is a legally binding agreement under which industrialized countries will reduce their collective emissions of greenhouse gases (CO2 、 CH4 、 N2O 、 SF6 HFCs 、 PFCs) by 5.2 % compared to the year 1990 from 2008 to 2012. Their countries emissions target: EU-15 reduce 8 %US reduce 7 %Canada, Hungary, Japan, Poland reduce 6 %Croatia reduce 5 %New Zealand, Russian Federation, Ukraine reduce 0 %Norway, increase 1 %Australia, increase 8 %Iceland, increase 10 %



Hydrogen Energy

S.S. Hsiehppt. 06

Hydrogen is a chemical element that carries energy. It can be stored in either liquid or gaseous form. Today, hydrogen is not a substance we consciously encounter in everyday life, although it is used

It is normally bound to other substances, it is colourless, odourless, non-toxic and when it burns in

extensively in many industries.

air, that reaction produces only water.



Hydrogen Energy (continued)

S.S. Hsiehppt. 07

Besides the fuel of boiler and steam turbine, the hydrogen can often be used to the fuel cell to generate electricity most directly, because it actuallygenerates electricity efficiency up to 40%~60%.



Hydrogen Applications

The applications of hydrogen energy are following :

• As the fuel of the fuel cell

• As the fuel of family

• As the fuel of the vehicle engine or the energy of the

electronic device

• As the fuel of the aircraft

• As the materials of the chemical industry

• As the fuel of the boiler and steam turbine

S.S. Hsiehppt. 08



Hydrogen Fuel Stations

S.S. Hsiehppt. 09

• Hydrogen Fuel Stations – Worldwide accumulated, sorted by region (1995-2009)

Germany36%

Japan12%

North-America16%

RegionalOrganization

for Europe17%

Other19%



Hydrogen for Fuel Cell

S.S. Hsiehppt. 10

The electrons flow from the fuel cell's anode to

cathode, thereby generating electricity. Meanwhile

, the hydrogen atoms that have shed their electrons

become hydrogen ions and travel through a polymer

electrolyte membrane to reach the cathode side.

There, with the help of a catalyst on the cathode, the

hydrogen ions and electrons join with oxygen to formwater.



Fuel Cell

S.S. Hsiehppt. 11

Fuel cell is a device that converts the chemical energy of a fuel and an oxidant directly into electricity. The principal components of a fuel cell include electrodes (anode and cathode), and membrane-

Fuel cell stacks available and under development are silent, produce no pollutants, have no moving parts, and have potential fuel efficiencies far beyond the most advanced reciprocating engine or gas turbine

electrode assembly (MEA).

power generation systems.



Fuel Cell ( continued )

S.S. Hsiehppt. 12

• A Traditional Design of PEMFC

H2 inlet

H2 outlet

Air inlet

Air outlet

(1)

(1)

(2)

(2)

(3)

(3)

(4)

(4)

(5)

(1) End plate

(2) Current collector

(3) Flowfield plate

(4) Gasket

(5) MEA



Fuel Cell ( continued )

• High efficiency to produce energy

(From :http://www.broadcastpapers.com/m 20091019)

S.S. Hsiehppt. 13

* LHV = lower heatingvalue.

* A thermodynamic term that indicates the heat needed to raise steam from liquid water.



Fuel Cell Advantages

S.S. Hsiehppt. 14

• Working time is longer than the traditional batteries It can offer energy for a long time when the hydrogen supply with.

• Short time in supplement fuel process After the fuel is used up, then it can run once again if we supply

the hydrogen constantly.

• Clean in the energy production process The products are only water and heat.



Types of Fuel Cell

S.S. Hsiehppt. 15

Fuel Cell Type

Electrolyte Anode Gas Cathode Gas Temperature Efficiency

Proton Exchange Membrane ( PEMFC )

solid polymer membrane

Hydrogenpure or

atmospheric oxygen

25OC ( 80OF )

35-60％

Alkaline ( AFC )

potassium hydroxide

Hydrogen pure oxygen below 80OC 50-70％

Direct Methanol ( DMFC )

solid polymer membrane

methanol solution in

water

atmospheric oxygen

75OC ( 180OF )

35-40％

Phosphoric Acid ( PAFC )

Phosphorous hydrogenatmospheric

oxygen200OC ( 400OF )

35-50％

Molten Carbonate ( MCFC )

Alkali - Carbonates

hydrogen, methane

atmospheric oxygen

650OC ( 1200OF )

40-55％

Solid Oxide ( SOFC )

Ceramic Oxidehydrogen, methane

atmospheric oxygen

800-1000OC ( 1500-

1800OF )45-60％



+ -2 2

1O 2H 2e H O

2

Anode Reaction

Cathode Reaction

2 2 2

1H O H O

2

Total Reaction

+ -2H 2H +2e

Ideal Voltage

1.23V

PEMFC

S.S. Hsiehppt. 16

( From : http://fuelcellsworks.com 20091019)



This type of fuel cell operates at low temperatures (25OC), and has a high power output density, and

PEMFC (continued)

S.S. Hsiehppt. 17

It is suitable for use in light-duty vehicles, buildings, cell phones, and as replacements for small

can vary output to meet demand.

rechargeable batteries.



AFC

S.S. Hsiehppt. 18

Anode Reaction

Cathode Reaction

Total Reaction

- -2 2

1O H O 2e 2OH

2

- -2 2H +2OH 2H O+2e

2 2 2

1H O H O

2

( From : http://www.fctec.com/fctec_types_afc.asp 20091019)



AFC (continued)

S.S. Hsiehppt. 19

Alkali fuel cells (AFC) use a concentrated solution of

potassium hydroxide (KOH) in water as an

electrolyte. Hydroxyl ions (OH-) migrate from the

cathode to the anode in these fuel cells. Hydrogen

gas supplied to the anode reacts with the OH- ions to

produce water. The reaction releases electrons,

which provide the electrical power. And AFC are 60percent efficient.



+ -2 2

3O +6H +6e 3H O

2

Anode Reaction

Cathode Reaction

Total Reaction

Ideal Voltage

1.18V

DMFC

3 2 2 2 2

3CH OH+ O +H O CO +3H O

2

+ -3 2 2CH OH+H O CO +6H +6e

S.S. Hsiehppt. 20

e-

load

Proton Exchange Membrane

CH OH3 Air (O )2

ElectrodeAnode

Cathode:Pt catalyst loading

:Pt-Ru catalyst loading

6H+

2H O and Air2 2

CH OH3

CO and H O

CH OH + H O + 1.5O3 2 2 CO + H O2 2

Direct Methaol Fuel Cell



The DMFC draws hydrogen from the methanol directly at operating temperatures of 50-100OC.

DMFC (continued)

S.S. Hsiehppt. 21

It is suitable for applications such as cell phones andlaptop computers.



Anode Reaction

Cathode Reaction

Total Reaction

+ -2H 2H +2e

+ -2 2

1O +2H +2e H O

2

2 2 2

1H + O H O

2

(From: http://www.fctec.com/fctec_types_pafc.asp 20091019)

PAFC

S.S. Hsiehppt. 22



This type of fuel cell operates at high temperatures (150 ~ 200OC) to maintain the ionic conductivity of phosphoric acid.

It generates electricity at 40% efficiency (80% if the steam produced is used for cogeneration) and can use impure hydrogen as fuel.

PAFC (continued)

S.S. Hsiehppt. 23



Anode Reaction

Cathode Reaction

Total Reaction

- -22 2 3

1O +CO +2e CO

2

-2 -2 3 2 2H +CO CO +H O+2e

2 2 2 2 2

1H + O +CO H O+CO

2

MCFC

S.S. Hsiehppt. 24

( From : http://fuelcellsworks.com 20091019)



MCFC are expected to achieve power efficiencies of 60% (85% with cogeneration) and operate at very high temperatures (650OC) to maintain electrolyte

conductivity.

This type of fuel cell is suitable for large electric utility

applications.

MCFC (continued)

S.S. Hsiehppt. 25



-2 -2 2H +O H O+2e

- -22

1O +2e O

2

2 2 2

1H + O H O

2

Anode Reaction

Cathode Reaction

Total Reaction

SOFC

S.S. Hsiehppt. 26

( From : http://fuelcellsworks.com 20091019 )



This type of fuel cell is suitable for large, high-powerapplications such as industrial or electricity generators.

Its operating temperatures is 1000OC, and it is expected to achieve power efficiencies of 60% (85% with cogeneration).

SOFC (continued)

S.S. Hsiehppt. 27



Fuel Cell Comparison

S.S. Hsiehppt. 28

Fuel CellType

Advantage Fault Application

PEMFC

‧ Operate at low temperatures ‧ Proven long operating ‧ Have fast startup time ‧ Have high power densities

‧ Additional humidification ‧ A platinum catalyst

is expensive

‧ Household electrical generation ‧ Light-duty

transportation

DMFC

‧ The fuel storage problems is easy ‧ Methanol is easier to

transport and supply

‧ Slow startup time ‧ Methanol crossover ‧ Expensive

‧ Cellular phones ‧ Laptops ‧ Remote power ‧ Transportation

SOFC

‧ Can make fuel with the natural gas or the methane ‧ Can make oxidizer with air

‧ Operate at high temperature

‧ Electrical generators ‧ Large power plant ‧ Industrial power

supplies



Micro Fuel Cell

S.S. Hsiehppt. 29

Distinctive, high density energy sources for portable products

Hybrid battery rechargers : separate (desktop)

Portable Electronics : radio, PDA, laptop, cellular phone, portable power source

• Applications



Micro Fuel Cell (continued)

S.S. Hsiehppt. 30

Small, lightweight

Inexpensive(?)

Low (room) temperature operation

Unique multi-layer (ceramic, silicon, etc.) miniaturization possible

• Advantages of Micro PEM Fuel Cells




S.S. Hsiehppt. 31

e-

load

Proton Exchange Membrane

Air (O )2

ElectrodeAnode

Cathode:Pt catalyst loading

:Pt catalyst loading

2H+

H O and Air

Proton Exchange Membrane Fuel Cell

H2

H2

H + 0.5O2 2 H O2

2

• H2 Proton Exchange Membrane Fuel Cell (H2 PEMFC)




S.S. Hsiehppt. 32

Three to one layer design: combine current collector , flow filed plate and backing layer

Microstructure by MEMS fabrication:

(a) thin film deposited and layer growth with surface mount technology (b) microflow channel by excimer laser processing

• New Design




S.S. Hsiehppt. 33

• Structure

H2 inlet

H2 outlet

Air outlet

Air inlet

(1)

(1)

(2)

(2)

(3)

(3)

(4)

(1)End plate (2000 µm)

(2)Flowfield plate (200 µm)

(3)Gasket (200 µm)

(4)MEA (include GDL) (650 µm)




S.S. Hsiehppt. 34

Minimized fuel cells and reduce its weight.

Catalyst (Pt) loading reduced as low as 0.15mg/cm2

(traditional design is 0.4mg/cm2).

Flow field plate have a large effective flow passage even up 20% increase in contact area.

• Advantage of New Design



Serpentine Flow Field Interdigitated Flow Field Mesh Flow Field


S.S. Hsiehppt. 35

• Gasket An acrylic structure to protect and observe the fuel cell.

• Flow Field Plate、 Current Collector



• Membrane-electrode assembly (MEA)

An assembly consisting of an anode, and electrolyte, and a cathode (3 layer MEA), and may include gas diffusion layers.


S.S. Hsiehppt. 36



MEA Morphology

S.S. Hsiehppt. 37

SEM image showing the morphologicalcondition of thin platinum sputtered on

AFM image showing the morphologicalcondition on thin platinum (200x200nm2)

Nafion 117 (1.5x1.2μm2)



Micro Fuel Cell

S.S. Hsiehppt. 38

flow-field plate fuel cell



Experiments

lamp

Air in

H2 in

H2 out

S.S. Hsiehppt. 39



Fuel Cell Polarization

S.S. Hsiehppt. 40

As the fuel cell is operating, the cell potential decreases from its reversible (ideal) value for the

sake of the irreversible losses.

These losses are often referred as polarization , which include activation polarization, concentration polarization, ohmic polarization.



Fuel Cell Polarization (continued)

S.S. Hsiehppt. 41

• Activation Polarization

It happens in the delayed phenomenon of reactive speed when fuel cells start the electric chemical reaction on the electrode surface.

• Ohmic PolarizationIt happens on the move of ion in the electrolyte and the impedance of electron move.

• Concentration PolarizationIt happens when the fuel cells don’t maintain the proper concentration of reactant on the electrode surface.



Experimental Results

0 50 100 150 200 250 3000.0

0.2

0.4

0.6

0.8

1.0

1.2 @P=153kPa@T=50oC

volta

ge

(V)

current density(mA/cm2)

interdigitated serpentine mesh

S.S. Hsiehppt. 42



Experimental Results (continued)

0 50 100 150 200 250 3000

20

40

60

80

100@P=153kPa@T=50oC

Pe

rfo

rma

nce

(mW

/cm

2 )

current density(mA/cm2)

interdigitated serpentine mesh

S.S. Hsiehppt. 43

po

we

r d

en

sity

(mW

/cm

2 )


MEM Department NSYSUS.S. Hsieh

ppt. 44

Micro Fuel Cell Stack Design

Gasket: 5000μm

Air InH2 In

End plate:450μm

Bipolar plate: 650μm

MEA(include GDLs): 750μm

H2 OutAir Out

H2 H2 H2 Air Air Air

Total thickness of 2-cell stack (not include Gasket): 3.05 mmTotal thickness of 7-cell stacks (not include Gasket): 10.05 mm



ppt. 45

Bipolar Plate Fabrication

1. Clean Cu film (50μm) 2. Spin coating SU-8

200μm

Heating

3. Soft bake 4. Exposure

Mask

5. Post exposure bake 6. Development

Heating

Cu film

SU-8

Cu electroforming

Substrate

200μm

7. Electroforming

200μm 200μm

8. Remove photoresist 9. Redo 1-8 processes



ppt. 46

Bipolar Plate Fabrication (continued)

650μm

3-D image of electroforming bipolar plate



ppt. 47

Experimental Results (PEMFC)

The performance test for 2-cell stack at fixed anode P=97kPa and different cell temperature



ppt. 48

Experimental Results (PEMFC) (continued)

0 50 100 150 200 2500.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

0

50

100

150

200

250

300

350

400

(b) P=97kPa

S

tack

vo

ltag

e (

V)

Current density (mA/cm2)

Tstack

=25oC

Tstack

=35oC

Tstack

=50oC

Po

we

r d

en

sity

(m

W/c

m2 )

The performance test for 7-cell stack at fixed anode P=97kPa and different cell temperature



ppt. 49

(a) Image for 7-cell stack during operation

(b) Lateral image of 7-cell stack

Experimental Results (PEMFC) (continued)



ppt. 50

Experimental Results (DMFC)

Flow plate

(36×33 mm2)

Channel pass(1 channel 6 pass)

Inlet (5 mm OD. PMMA tube)

Outlet (5 mm OD. PMMA tube)

Channel

Rib

Screw

(4 mm OD. ×8)

PMMA

(60×60 mm2)

A typical transparent of DMFC single cell structure



ppt. 51

Experimental Results (DMFC) (continued)

0 100 200 300 400 500 600 700 8000.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

Pow

er d

ensi

ty(m

W/c

m2 )

Cel

l vol

tage

(V)

Current density(mA/cm2)

0.5 M 1 M 1.5 M 2 M

Temperature : 80 oCFlow rate : 10 sccmChannel width : 2 mm

Concentration effect on performance curve



ppt. 52

Experimental Results (DMFC) (continued)

0 100 200 300 400 500 600 700 800 9000.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0

20

40

60

80

100

120

Concentration : 1 MFlow rate : 10 sccmChannel width : 2 mm

Ce

ll vo

ltag

e(V

)

Current density(mW/cm2)

40 oC

60 oC

70 oC

80 oC

Po

we

r d

en

sity

(mW

/cm

2 )

Temperature effect on performance curve



• Mobile phone

DMFC mobile phone charge unit

S.S. Hsiehppt. 53

( From : http://www.fuelcell.no/fuel_cell_types_pemfc_eng.htm ) (2009/10/19)

( From : http://www.slashphone.com/111/2638.html ) (2009/10/19)

Fuel Cell Applications

DMFC mobile phone



ppt. 54

• Transportation vehicle

Honda’s 2008 FCX fuel cell vehicle – it is powered by a Honda designed and manufactured fuel cell stack.

( From : http://automobiles.honda.com/fcx-clarity/refueling.aspx ) (2009/10/19)

Fuel Cell Applications (continued)



Conclusions

S.S. Hsiehppt. 55

No matter in food, clothing, lives, transportation, education, amusement, the energy is closely linked with our life. So on the premise of no pollution for the environment, it is a good choice to use the fuel cell togenerate electricity.

We can believe that under the regulation of Kyoto Protocol, it will be sure to have brighter prospects touse the fuel cell to generate electricity in the future.



References• S.-S. Hsieh, J.-K. Kuo, C.-F. Hwang, and H.-H Tasi, “A Novel Design and Microfabrication for a Micro PEMFC,” Microsystem Technologies, Vol.10, 2004, pp. 121-12

6. • S.-S. Hsieh, C.-F. Huang, J.-K. Kuo, H.-H Tasi, and S.-H. Yang, “SU-8 Flow Field Plates for a Micro PEMFC,” Journal of Solid State Electrochemistry, Vol.9, 2005, 121- 13

1.

• S.-S. Hsieh, C.-L. Feng, C.-F. Huang, “Development and Performance Analysis of a H2/air Micro PEM Fuel Cell Stack,” Journal of Power Sources, Vol.163, 2006, 440-449.

• S.-S. Hsieh, Y.-J. Huang, “Measurements of Current and Water Distribution for a Micro-PEM Fuel Cell with Different Flow Fields,” Journal of Power Sources, Vol.183, 2008, 193-204.

• DMFC mobile phone charge unit (http://www.fuelcell.no/fuel_cell_types_pemfc_eng.htm )

• DMFC mobile phone (http://www.slashphone.com/111/2638.html )

• Honda’s FCX fuel cell vehicle (http://automobiles.honda.com/fcx-clarity/refueling.aspx )

S.S. Hsiehppt. 56



Thanks for Your Attention !