fuel cell seminar oct 2731, 2008, phoenix, arizona€¦ · · 2008-11-122008-11-12 · • fuel...

Fuel Cell Research Center Fuel Cell Research Center

Development of a DMFC Development of a DMFC Powered Powered Humanoid Robot Humanoid Robot

HanIk Joh, Tae Jung Ha, JaeHyong Cho, Heung Yong Ha,

Jong Ho Kim, SooKil Kim, TaeHoon Lim, BaekKyu Cho*, JunHo Oh*

a Fuel Cell Research Center, Korea Institute of Science and Technology b Korea Advanced Institute of Science and Technology

Fuel Cell Seminar Oct 2731, 2008, Phoenix, Arizona

2008. 10 . 30.


1. Introduction

Ø The Fuel Cell Research Center at KIST

Ø DMFC prototypes

2. Experiment

Ø MEAs, bipolar plates, stacks

Ø BOPs, PMS

3. Results

Ø Performance of a stack

Ø Control of MeOH and temperature

Ø Operation of a DMFCRobot system

4. Summary

Outline


• Power Generation – Molten Carbonate Fuel Cells (MCFC) – Solid Oxide Fuel Cells (SOFC)

• Transportation – Polymer Electrolyte Membrane Fuel Cells (PEMFC)

• Portable Power Sources – Direct Methanol Fuel Cells (DMFC) – PEMFC with a Micro Fuel Processor for Portable Powers

• Hydrogen Generation – Reformer for MCFC – Fuel Processor for PEMFC

The Fuel Cell Center at KIST The Fuel Cell Center at KIST


Ø 2008 Manpower : 70 – Regular Staff : 17 (10 Ph.D.’s) – Visiting Scholar : 1 – Researcher : 10 (10 MS and BS) – Student : 41 (22 Domestic, 6 Foreign)

Ø 2008 budget : ~ $ 7 million


PEM

Activities on DMFC at KIST

1. Advanced MEAs ü Low catalyst loading ü MEA fabrication process

2. Durability and regeneration ü Degradation mechanism ü Performance recovery

3. Electrocatalysts ü Carbon supports ü Ptalloy catalysts

4. Membrane modification ü Surface modification ü Low methanol crossover

5. Bipolar plates ü Flow field design ü Simulation

6. DMFC stacks ü Monopolar stacks ü Large size stacks ü High power density

7. Methanol supplying systems ü Sensorless controller ü Smaller and simpler

8. DMFC systems ü For Robots ü For Portable electronics ü For emergency usage


Efforts toward Commercialization

? 200 cc 1 liter 20 W 15 hr Samsung SDI

2006 200 cc 1 liter 25 W 10 hr LG Chem

2006 3 cc 126 cc 1.0 W 5 hr Hitachi

2009 50 cc ? 6hr talk time Toshiba

2012 50cc ?

1kW Yamaha

Prototypes Prototypes Commercia Commercia lization lization goal goal

Fuel Fuel volume volume

System System volume volume Power Power Company Company

Panasonic 5hr operation

http://ocn.amikai.com/AmiWeb?ami_url=http%3A%2F%2Fkaden.watch.impress.co.jp%2Fcda%2Fparts%2Fimage_for_link%2F1023-72-1-1.html&r_n=8787


• Power density ü Membrane, Catalyst, MEA

• Energy density ü Balance of plant, stack volume

• Power output control ü Power change at various temperatures ü Start up at low temperature

• Fuel cell system design ü Air intake, water disposal, heat release

• Reliability ü Dust, fuel impurities, dry up during storage

• Safety ü Eliminate noxious effluents(methanol, formaldehyde, CO, etc)

• Infrastructure ü Delivery of fuel, fuel exchange system

• Cost

Ø Niche markets having competitive edge

DMFC Technical Challenges


Fabricate a 400Wclass DMFC system including stack, BOP and PMS

Investigate the operational characteristics of the fuel cellbattery

hybrid system while operating a robot

Develop a 400W DMFC/battery hybrid system

to power a humanoid robot

Goals


MEA, Bipolar Plate and Stack

MEA: 138cm 2

Bipolar plate 42cell stack

Single cell


Fuel Cell System with BOP

Integrated BOP and a stack

The stack and the BOP were assembled to build a DMFC system


Flow Diagram of Power and System Control

PMS

The DMFC system was integrated with a battery and a power management unit to make a standalone DMFCbattery hybrid system.


Astroboy

Robots

R2D2

Asimo

The Transformer

Taekwon V


300Wh NiMH / 90 min Power/operation time

56 Kg Weight

HUBO ( KHR3 )

1.25 km/h Maximum velocity

Four direction Walking direction

125 cm Height

41 Degree of freedom

KAIST Humanoid Robot Hubo was created by the robot team at KAIST, led by Prof. JunHo Oh

KAIST is one of the prominent universities in Korea


Power Consumption by HUBO

< Measurement of HUBO’s current

consumption for programmed actions >

(Region 1) Position compensation while hung down from hook

(Region 2) Position adjustment on the ground

(Region 3) Programmed actions for standing still, handshake,

and talking with hands

(Region 4) Programmed actions for walking

Power Consumed voltage, current

Conditions

12V, 5A

24V, 30A

24V, 10A

24V, 5A

24V, 1A

Controller

Maximum load

Walking

Programed action

Position compensation

HUBO ( KHR3 ) consumed power

240 W

720 W

120 W

24 W

60 W

Idle Walking Max


The 42cell stack displayed almost the same performance as the single cell

150mA/cm 2 @ 0.46V:, 70 mW/cm 2 , 405W

Performance of DMFC

0 50 100 150 200 250 0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Stack voltage, Stack power Shortstack voltage, Short stack power Single cell voltage, Single cell power

Current density [mA/cm 2 ]

Voltage [V

]

Stack vs. Shortstack vs. Singel cell performance

10

0

10

20

30

40

50

60

70

80

90

100

110

Pwer density [m

W/cm

2 ]

single cell, shortstack = 70 o C full stack = RT Feed, air = RT

Single cell

42cell stack

Comparison btn the 42cell stack and a single cell.

stack

Single cell


Effect of Feed Conc

v Cell temp. increased with increasing MeOH conc. even at open circuit condition

v With 1.0M, the temp reached 80oC, not suitable for the stack

v 0..8M MeOH gave the better performance than 0.5 M

0 10 20 30 40 20

30

40

50

60

70

80 Cathode inlet

Temperature distribution at O.C.

0.5 M MeOH 0.8 M MeOH 1 M MeOH

Temperature [°C]

Cell number

Anode inlet

MeOH in Air in

Characteristics of the 42cell stack

Temp at open circuit

0 5 10 15 20 25 30 0

5

10

15

20

25

30

35

Voltage [V

] Current [A]

Pow

er [W]

voltage05 power05 voltage08 power08

0.5 M vs. 0.8 M (λ=3.6/3.6)

0

50

100

150

200

250

300

350

400

450

500

0.5M

0.8M

Performance

1.0M

0.5M

0.8M


0 10 20 30 40 50 60 70 80 90 100 110 120 0.0

0.1

0.2

0.3

0.4

Time [hr]

0

2

4

6

8

10

12

14

16

18

20

∆P Ca

∆P An

Power

Voltage

Power [W

], ∆P [kPa]

Voltage [V

]

Continious long term test for 10h per day(20060731~0809)

Ø A continuous operating mode while running the cell 10 hrs a day ØThere was not appreciable degradation

Ø The air supply to the stack was continually interrupted for 2 sec every 3 min

Longterm Stability of Single Cells

v The single cells showed a very stable performance over the 630hrs regardless of

operation mode used.


v The sensorless controller was

designed to make up the methanol

consumption by the stack.

v A methanol consumption map has

been built by measuring MeOH

consumption rates at varying operating

conditions.

v At first, the MeOH con is lower than

the set point

v In 20 minutes, the methanol conc

approaches a setting value within a

10% error margin.

Sensorless Control of MeOH Conc.

0 20 40 60 80 100 0.0

0.2

0.4

0.6

0.8

1.0

MeO

H conc. [m

ol/L]

Time [min]

Under a load of 20 A O.C.

0.8 M Neat MeOH

stack

Mixer

Calculating MeOH consumption rates


v Temperature of the stack was controlled to around 70 o C by using a heat exchanger.

v Temp < S.P., cooling fan = OFF

v Temp > S.P., cooling fan = ON

v The air Inlet temperature increased due to the heat released by air blower

Control of Stack Temp.

0 20 40 60 80

20

30

40

50

60

70

80

Temperature [ ° C

]

Time [min]

Anode in Anode out Cathode in Cathode out Anode heat exchanger

Cathode out

Cathode in

Anode out

Anode in

stack

Heat exchanger

recycle

MeOH Mixe r


Power Management Unit

vVolume : 3 liter (12 x 25 x 10 cm)

DC/DC converter: DC 15~40V è DC 29V

v To regulate the voltage of the electricity from the stack

v To distribute the power to the robot and the BOP

v DC/DC converting eff. =95%

v Current limit: 30A/20A/17A (PMU/battery/stack)


Integration into Robot

Stack & BOP

PMU

Battery

Hubo


Operation of the Robot

< Consumed power> BOP = 24V x 3A = 72W

PMS = 29V x 1A = 29W

When the total load by the robot and the BOP is less than the power from the stack, the power is covered by the stack.

As the total load is higher than the stack power, the power deficit is made up by the battery.

As the robot enters the idle state, consuming less power, the surplus electricity from the stack is used to recharge the battery.

0 10 20 30 40 50 60 70 80 90

5

0

5

10

15

20

25

Current [A

]

Time [min]

Stack Robot Battery Total current

Total

Stack

Robot

Battery

FC > Ro + BOP FC < Ro + BOP

Load sharing btn the stack and the battery


Energy Efficiency

Net electric energy efficiency

Beside the heat and kinetic losses, the methanol losses due to crossover and vaporization were the largest part: 32%

The net energy efficiency to electricity was 22%


Summary

v The stack used in the robot presented almost the same performance as

a single cell showing the bipolar plate design and stack assembling

technique were good.

v The 400W class DMFC stack showed very stable and high performance

v Pumps, an air blower, a heat exchanger,a methanol controller, a PMU

and a battery were successfully integrated into a DMFC system to make

a standalone DMFCbattery hybrid power generator.

: Stack power density = 117W/L, system power density = 43 W/L

v The humanoid robot ran stably with the power supplied by the DMFC

hybrid system.


DMFC Lab members

KIST DMFC team members

Dr. H.Y. Ha


We welcome collaboration work with companies from abroad!!!

fuel cell seminar oct 2731, 2008, phoenix, arizona€¦ · · 2008-11-122008-11-12 · • fuel...

Documents