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Portable fuel cell systems

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					     Electrochemical Reaction & Technology Laboratory (ERTL)




System development of Portable fuel cells
    Portable fuel cell systems

                       Jaeyoung Lee

                     September 19, 2006
                                                                                                                http://www.h2fc.re.kr



            Energy demand & fuel cells

   Energy 수요공급 전망
   세계에너지demand                                       Capacity
                                                      Capacity     mW        2W      50W         3kW        75kW        MW

                                                                                     PFC
                                                    Application
                                                     Application

                                                                   Micro    Mobile    Lab-top Small-scale   Electric    Distributed   Power
                                                                   device   phone    computer power plant   Vehicle    power system    plant


(Source: Energy Needs, Choices and Possibilities,                                                                             MCFC
                                                                                                                              MCFC
Scenarios to 2050, Shell)
                                                                                             PEMFC (H2))
                                                                                             PEMFC (H2
                                                     Fuel Cells
                                                      Fuel Cells
                                            30%                                    DLFC
                                                                                  DMFC
                                                                                   DMFC                                        PAFC
                                                                                                                                PAFC

                                                                       μ-FC
                                                                        μ-FC                                  SOFC
                                                                                                               SOFC




                                           Power range: a few ~ ca. 3kW

                                                                                                                                               5
                                                     http://www.h2fc.re.kr



 ISSUES in commercialization

                                 CATALYSTS
                                 MEMBRANES
                    Fuel Cells   BPP & GASKETS
                                 STACK




      EDUCATION
   SAFETY & COST
CODE & STANDARD
 INFRASTRUCTURE     ISSUES


                                                 BATTERY
      CUSTOMERS                   BOP            PUMPS & Valve
                                                 PCB BOARD (PMS)
       acceptance                                Fuel tank
                                       http://www.h2fc.re.kr



               Choices

                         μ-SOFC




                 PFC
μ-reformer &
 NaBH4
 PEMFC

                            DLFC
                          (FA, MeOH)
http://www.h2fc.re.kr
                                              http://www.h2fc.re.kr



                Portable energy systems

   DC power
    charging       Li polymer/ion battery
   3 ~ 4 hrs




   Methanol,
  gasoline &     Micro PEMFC with reformer
 butane, etc.
                                               Portable
                                              application
NaBH4 + NaOH
    Hydrogen        PEMFC with NaBH4            IT devices
                                             Military systems
                                             Emergency case


 Formic acid
   Methanol       Direct liquid fuel cells
    Ethanol
                              http://www.h2fc.re.kr



       LG Chem




            Components ~ 1.0L
Sep. 2005   Fuel tank ~ 0.2L
            Average power = 25 W
            10 hrs operation
                                 http://www.h2fc.re.kr



                      SAMSUNG


    Nov. 2005




Systems ~ 1.0L
(230 x 82 x 53 mm3)
Fuel tank ~ 0.2L
Average power = 20W             April 2004
15hrs operation
                                                                http://www.h2fc.re.kr



                            TOSHIBA

CeBIT 2004                          CeBIT 2005

                                     PORTEGE M300
 PORTEGE M100                        B5-sized sub-notebook PC
 B5-sized sub-notebook PC




                            Systems ~ ca. 1.0L
                            Fuel tank ~ ca. 0.2L
                            20Whr
                            10hrs operation
                                       http://www.h2fc.re.kr



             ANTIG

CeBIT 2005




                                 Systems ~ ca. 1.0L >
                                 Fuel tank ~ ca. 0.2L
                                 10W




              CeBIT 2006
                   CD-Rom size
                   45W / 8hrs
                   1.7kg
                   Antig & AVC
                                       http://www.h2fc.re.kr



                  NEC
Oct. 2004

                        Systems ~ 1.0L
                        Fuel tank = 250cc
                        10hr operation




  WPC EXPO 2004
                      http://www.h2fc.re.kr



HITACHI


          July 2004
                             http://www.h2fc.re.kr



 Fujitsu & Millennium cell


                 Jan. 2004




Systems ~ ?.?L
Ave. = 15W
10hr operation
            http://www.h2fc.re.kr



Panasonic
                                       http://www.h2fc.re.kr



Sanyo & IBM


                        April 2005




weighs 4.4 pounds
8 hrs operation
a single 8-cubic inch fuel cartridge
                                             http://www.h2fc.re.kr



             UltraCell




Production model will be available in 2007
                             http://www.h2fc.re.kr



Samsung SDI




  Butane- PEMFC Power pack

220g 소형 부탄 캔
100W 평균 출력/5시간 이상 사용
레저용 소형 컬러TV (60W 기준)/8시간
노트PC (20W 기준)는 20시간
2007년 말 상용화 예정
                              http://www.h2fc.re.kr



P-SOFC: Adaptive Materials, Inc.
                   http://www.h2fc.re.kr



20W P-SOFC (AMI)
                                                       http://www.h2fc.re.kr



        Direct liquid fuel cells


                    Anode:     CH3OH + H2O       = CO2 + 6H+ + 6e-
                    Cathode:   1.5 O2 + 6H+ + 6e- = 3H2O
                    Overall:   CH3OH + 1.5O2      = CO2 + 2H2O
                               HCOOH + 1.5O2 = CO2 + H2O
                               HCHO + O2          = CO2 + H2O
                               C2H5OH + 3O2     = 2CO2 + 3H2O




Liquid fuels flow
                                                               http://www.h2fc.re.kr



     Alternative liquid fuels

                     Methanol   Formic Acid   Dimethyl Ether      Ethanol
                     (CH3OH)     (HCOOH)        (CH3OCH3)       (CH3CH2OH)
 # of generated
                        6           2              12                12
    electrons

Boiling Temp. (oC)     65          100             -23               78

 Energy Density
                      4690         2086             -               6280
     (Wh/L)
    Kinetics          slow       very fast        slow           very slow

   Cross-over         large       small         small ??              -

     Toxicity         toxic     non-toxic?        toxic          non-toxic

                                                                High temp.
       etc              -            -             gas
                                                                 reaction
                                                                     http://www.h2fc.re.kr



          DLFC components to systems




Catalyst synthesis       Catalyst           Electrode fabrication      Electrode




 Polymer Electrolyte   Membrane-electrode
     Membrane           assembly (MEA)
                                                           Stack           System


                                            Graphite bipolar plate
                                                                                                                                                                  http://www.h2fc.re.kr



                                               50W DMFC Stacks
                                                                                    Number of cell       6
                                                                                    Electrode area       106 cm2
                                                                                    Cell pitch           3.8mm
                                                                                    Stack                49x105x161 (mm)
                                                                                    Temperature          Room temperature
                                                                                    Operation conditions 2M MeOH @ 25CC/min & Air 12slm
                                                                                    MEA
                                                                                       Membrane          Nafion-115
                                                                                       Anode              5mg PtRu/cm2
                                                                                       Cathode            5mg Pt/cm2
                                                                                    Maximum Performance = 54W, 90mW/cm2

                                                                   60
                        Stack Power
              4.0
                              7 slm Dry Air                                                                                                         Maximum Power Density
                              12 slm Dry Air
                                                                   50                                                                                        2 M MeOH
              3.5                                                                                                  120                                     1.5 M MeOH
                              17 slm Dry Air




                                                                                          Power Density (mW/cm )
                                                                                          2
                                                                   40                                                                                       1 M MeOH
Voltage (V)




                                                                                                                   100                                     0.5 M MeOH
              3.0
                                                                        Power (W)

                                                                   30
                                                                                                                    80
              2.5
                                                                   20
                                                                                                                    60
              2.0
                                                                   10
                                                                                                                    40
              1.5
                                                                   0
                                                                                                                    20
              1.0
                    0      5     10     15     20   25   30   35                                                     0
                                   Current (A)
                                                                                                                         Cell 1   Cell 2   Cell 3    Cell 4   Cell 5   Cell 6
                                                            http://www.h2fc.re.kr



          LCD TV (50W) operation
                           Gas-liquid separator


                                                  2004 August


                                                        STACK



                                                        x  12V
                                                        DC-DC converter
                                                        Liquid pump

                                                        Fuel tank
                                                        (1.5M/500cc)
PROBLEMS
(a) low cell potential of about 2.3V low conversion efficiency (ca. < 70%)
(b) Uneasy of heat management: over 80°C
                                                              http://www.h2fc.re.kr



       Direct formic acid fuel cells
High thermodynamic potential            CO2         H+    H+       O2
Fast oxidation kinetics                          e
                                                     +
                                                              e
                                                 e H      H+ e
Lower cross-over                                 e H+     H+ e
Non-toxic & Easy handling of fuels    HCOOH      e
                                                    H+    H+
                                                              e    H2O
Low temp. operation
Simple device                  Anode:     HCOOH → CO2 + 2H+ + 2e-
Sufficient fuels               Cathode:   1/2 O2 + 2H+ + 2e- → H2O
                                            HCOOH + 1/2 O2 → CO2 + H2O 1.45 V
KIST DLFC system
                                                                                  http://www.h2fc.re.kr



              Goal in 2005 Summer- Demonstration


                                     Mixing Chamber &
                   Fuel Cartridge      Control Valve
   BOP
2005: 600cc                                                              Lap-
                                                                         Lap-top computer
2007: 300cc



        Sensor                                                       Liquid Recirculation Pump

     Gas-Liquid                                                      Air Compressor
      Separator
                                                                     Power Regulation Device
                                                                     & battery

 Fuel Cell Stack
                                                                           Fuel Cell Stack
                                                                          2005: 30W/600cc
                                                                          2007: 30W/500cc
                                                                            (6.0V, 5.25A)
                                    Air Blower Control Electronics
                 http://www.h2fc.re.kr



5 months later
                                     http://www.h2fc.re.kr



Stack development




          15 cells stack
          Max power : 50 W
          Normal power: 25W (5.6V, 4.5A)
          Size: 88 x 70 x 50 (mm) , 308 cc
                                                                                              http://www.h2fc.re.kr



                  The test of small DFAFC stack
                       Interesting zone
        1.8                                       80                               6M FA
                                                                                   ambient air
        1.6                                       70                               Anode: PtRu




                                                       p (mW cm-2) and T (oC
        1.4                                                                        Cathode: Pt
                                                  60                               Nafion 115
        1.2
                                                  50
         1                                                                           V
E (V)




                                                  40                                 V/Cell
        0.8
                                                                                     p
                                                  30
        0.6
                                                  20
        0.4
        0.2                                       10

         0                                         0                           OCV : 1.664 V     0.555V
                                                                               Max (P) : 74.7 mW/cm2
              0   50      100     150     200   250
                                                                               (continuously increasing)
                          i (mW cm-2)
                                                                                                http://www.h2fc.re.kr



         Optimization of stack materials
         SEALING is most important issue in a stacking of the cell
                                     Compatible        Sealing
                  Gasket Material                                          Other Considerations
                                      with FA         Integrity
                    red silicone      Medium            NO              fail under higher compression
                         PTFE             Yes           NO                  easy to manufacture
Gasket
                   glassy epoxy           No            NO                 difficult to manufacture
                 PTFE-coated epoxy        Yes           NO                 difficult to manufacture
                   grey silicone      Medium            YES                inconsistent thickness
                  epoxy+silicone      Medium            YES                    labor intensive
                  adhesive PTFE           Yes           YES                  simple and efficient



                         0.7                                                        70
                         0.6                                                        60




                                                                                         p (mW cm-2)
                         0.5                                                        50
                         0.4                                                        40
                   E/V




Bipolar Plate            0.3                                                        30
                         0.2                                                        20
                                                      Composite Material
                         0.1                          Graphite Material             10
                           0                                                      0
                                0    50             100           150          200
                                                        -2
                                                i (mA cm )
                                                                                                                                                             http://www.h2fc.re.kr



      Optimization of operation conditions
                                             Concentrations                                                                                      2 M CH3OH
                          2 M CH3OH                                                                                                              10 M HCOOH
      0.7                  6 M HCOOH                                  140
                                                                                                   45
                          10 M HCOOH
      0.6                 13 M HCOOH                                  120

                                                                                                   40




                                                                                        Temp / C
      0.5                                                             100




                                                                                        o
                                                                            P / mW cm
E/V




      0.4                                                             80
                                                                                                   35
      0.3                                                             60

      0.2                                                             40                           30
                                                                                                                                Temperature




                                                                                 -2
      0.1                                                             20
                                                                                                   25
      0.0                                                              0                                 0       100          200         300        400         500
            0       100          200         300       400          500                                                                    -2
                                               -2                                                                            I / mA cm
                            I / mA cm
                                                       1.5 cc/min                                                                                   250 cc/min
      0.6                                              3.0 cc/min      80                          0.6                                              500 cc/min         100
                                                       4.5 cc/min                                                                                   750 cc/min

      0.5                                                                                          0.5
                                                                                                                                                                       80
                                                                       60
      0.4                                                                   P / mW cm              0.4




                                                                                                                                                                             P / mW cm
                                                                                                                                                                       60
E/V




                                                                                        E/V
      0.3                                                              40                          0.3

                                                                                                                                                                       40
      0.2                                                                                          0.2
                                                                       20
                                                                                 -2




                                                                                                                                                                                  -2
      0.1                                                                                                                                                              20
                                                                                                   0.1

      0.0                                                              0
                                                                                                   0.0                                                               0
            0      50      100         150       200      250       300
                                                                                                             0         100          200             300           400
                                               -2
                             I / mA cm                                                                                       I / mA cm
                                                                                                                                            -2



                Formic acid flow rate.                                                                                 Air flow rate.
                             http://www.h2fc.re.kr



PMS block diagram for DLFC
                                                          http://www.h2fc.re.kr



                      Home-built PCB board
Liquid pump: 7.1 V operation
cooling fan: 3ea (12V operation)
Air pump:12V operation
Voltage range: 4.5V ~ 8.3V (buffer)
Initial start-up: double touch of 8.3V
Current range: max. 7.5A
Battery capacity: <10whr




board size: PCB board (with case) size: 80mm x 60mm x 20mm (96cc)
                                                                           http://www.h2fc.re.kr



                      Dynamic response
      20                                               4


      19
                                                       3.5

      18                                                           15 MEA stack
P/W




                                                                   HCOOH (6M): 26 ml/min




                                                             I/A
                                                       3
      17                                                           Dry air = 4600 sccm
                                                                   The stack temp. = 45 oC.
                                                       2.5
      16                                   Power
                                           Current
      15                                               2
           0   25     50              75   100       125
                           time / s


The fast recover of a performance           auxiliary power equipment is not needed.
(to act as a BUFFER between the power demands of stack and its transient response)
                                                               http://www.h2fc.re.kr



System optimization
                         stack attached to PCB board
          14                                               o
                                                                               70
                               stack temp reaches 60 C, cooling fan on
          12                                                                   60
          10                                                                   50
                          notebook brightness set to 75%
              8                                                                40




                                                                                    T/ C
        E/V




                                                                                 o
                                started dummy liquid pump
              6                                                                30
              4                     started playing                            20
                       notebook         an MP3
              2        power on                                                10
              0                                                              0
                   0      20        40         60      80        100      120
              10                                                           100
                             Voltage                Temperature
               8             3.0A
                                                                           80
                                         -2
                             92 mA cm
               6                                                           60




                                                                                 T/ C
        E/V
                                                    4.9A




                                                                                 o
                                                                -2
                                                    150 mA cm
               4                                                           40
                                     4.0A
               2                                                           20
                       OCV      123 mA cm
                                              -2


               0                                                           0
                   0         10         20     30                    40
                                      time (min)
                                                                            http://www.h2fc.re.kr



                   DLFC & Notebook computer


     KIST             LG Chem           Samsung             Toshiba              NEC




• ’05. 12.         • ’05. 09.         • ’05. 11.         • ’05. 03.         • ’04. 10.
• DFAFC            • DMFC             • DMFC             • DMFC             • DMFC
• 50W max          • 25W norm.        • 50W max          • 20Wh             • 1.0L system
• 25W norm.        • 1.0L system      • 20W norm.        • 1.0L system      • 0.25L fuel
• 1.15L system     • 0.2L fuel tank   • 1.0L system      • 0.2L fuel tank     tank
• 0.3L stack       • 10 hour          • 0.2L fuel tank   • 10 hour          • 10 hour
• 0.3L fuel tank                      • 15 hour
• 8 hour
                                                             http://www.h2fc.re.kr



                             Efficiency

Stack efficiency
ηstack = Pstack / Ptheoretical = 0.35 (21W @ 6M & 60°C)

BOP efficiency (P          = the power available to the laptop computer)
                              net output

ηBOP = Pnet output / Pstack = 0.65
                air compressor         cooling fans
−0.35 = (3.8W + 2.2W + 0.14W + 0.6W) / 21W
   power conditioning      liquid pump


PCB board efficiency
ηPCB board = 0.88

Total efficiency
ηstack × ηBOP = 0.23
                                     http://www.h2fc.re.kr



        Concluding remarks

  Sealing & Cooling (Stack)
Key issues

  Power management system needed
(Fuel Cells – Battery – Capacitor)

  BOP (Liquid pump, Air pump and fan)
should be developed.

  Catalyst – Membrane – BPP
(Still problems?)
                                                http://www.h2fc.re.kr



Small group,    but great members




                        GDL
              SYSTEM


  STACKING/
    GASKET
                              MEA/GATALYST



                                             CNL
                                             Seunglim Carbon
                                             Adelpia Lab.
                                             Design Dream
                                             FHI E-Lab
                                                       http://www.h2fc.re.kr



                     Plan by 2007/E
  Electrocatalyst: Pt or Au or Pd based anode
  Membrane: high protonic conductivity & low cost


  Catalyst Loading: 4.0     2.5mg/cm2
  Power density: 70       90mW/cm2


  Stack size: min. 35% down (300     195 cc)


  The total volume of the system: 1.45L   less than 0.95L
  (BOP should be miniaturized)


Co-work with lap-top computer company
to make one-body systems

				
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