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Battery – Electrochemical Capacitor Energy Storage for Hybrid

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Battery – Electrochemical Capacitor Energy Storage for Hybrid Powered By Docstoc
					Alternative Energy Storage System
   for Hybrid Electric Vehicles


               Tobias Andersson, Jens Groot,
     Helena Berg, Joachim Lindström, Torbjörn Thiringer




                                                          1
         Purpose and Method
• Hybrid electric vehicle: demands on an efficient
  energy storage system




                                                     2
  Energy Storage
• Energy- and power density




                              3
               Supercapacitor
A.k.a Electrochemical Double Layer Capacitor (EDLC), Ultracapacitor,
                   Electrochemical Capacitor (EC)


        • Extremely high capacitance (kF)
        • Low voltage (< 3 V)

                              1000-2000m2/kg

                A
      C                                   10-100 F/g
                  d
                              5Å

                                                                       4
Battery - Supercapacitor




                           5
Simulation of the system




                           6
Performance Parameters

  • Reducing of RMS-current

  • Reducing of power losses in
    battery

  • Total energy efficiency


                                  7
                              Load Cycle (ECE15-L)
          10



           5

                                                                             • Acceleration
           0



           -5                                                                • Constant velocity
P[W/kg]

          -10



          -15
                                                                             • Regenerative braking

          -20



          -25
                0   20   40   60   80   100    120   140   160   180   200
                                        t[s]




                                                                                                   8
                                Control Strategy
      2000




      1000
                                                                                 • Low pass filtering
         0


                                                                                 • Braking energy to EC
P[W] -1000




     -2000                                                                       • Loading of EC
     -3000

                                                           EC Power
                                                           Load Power
                                                           Battery Power
     -4000
             0   10   20   30   40   50     60   70   80        90         100
                                     t[s]




                                                                                                    9
                                Control Strategy
      2000




      1000
                                                                                 • Low pass filtering
         0


                                                                                 • Braking energy to EC
P[W] -1000




     -2000                                                                       • Loading of EC
     -3000

                                                           EC Power
                                                           Load Power
                                                           Battery Power
     -4000
             0   10   20   30   40   50     60   70   80        90         100
                                     t[s]




                                                                                                   10
Test System




              11
                           Test System
• EC
  10 units 2.5V, 2600F /
  28 units 2.0V, 2700F

• Battery
  50V / 100V, 60Ah
  NiMH

• DC/DC
  160 kW, 330A
  2-quadrants DC/DC
  converter



                                         12
                                     Results
                    - simulations and experiment
                          4000
                                     Load Power Sim.
                                     Load Power Exp.
                          3000       Battery Power Exp.

• Battery, 100V           2000
                                     Battery Power Sim.



                          1000


• EC, 56V                    0


                    P[W] -1000

                         -2000

• Equal to car           -3000

  with the weight        -4000

  of 250 kg              -5000


                         -6000

                                 0    20        40        60   80    100   120   140   160   180
                                                                    t[s]



                                                                                                   13
                        Results
                     - system performance

Performance Parameters Experiment    Simulation        Unit
RMS battery current             56                55   % of reference case
Power losses i battery          26                27   % of reference case
Total energy efficiency         95                94   %




                                                                     14
                  Example
      -Simplified system for a city bus, 220kW


NiMH-battery + EC                     NiMH-battery
Battery      310 kg                Battery       1150 kg
EC           280 kg                DC/DC          45 kg
DC/DC         90 kg

Total weight 680 kg                Total weight 1195 kg



                Weight reduction: 43 %
                                                           15
                  Conclusions
   Drawbacks                     Advantages
• Complexity                 • Weight reduction
• Difficult to estimate      • Improved battery lifetime
  the price                  • Reduced temperature
• Not tested in full scale     dependency
                             • EC could replace batteries



                                                       16

				
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posted:7/19/2011
language:Swedish
pages:16