1 alternative energy storage system for hybrid electric vehicles tobias andersson, jens groot,...
TRANSCRIPT
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Alternative Energy Storage System for Hybrid Electric Vehicles
Tobias Andersson, Jens Groot,
Helena Berg, Joachim Lindström, Torbjörn Thiringer
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Purpose and Method• Hybrid electric vehicle: demands on an efficient energy
storage system
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Energy Storage• Energy- and power density
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Supercapacitor
• Extremely high capacitance (kF)
• Low voltage (< 3 V)
d
AC
1000-2000m2/kg
5 Å
10-100 F/g
A.k.a Electrochemical Double Layer Capacitor (EDLC), Ultracapacitor, Electrochemical Capacitor (EC)
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Battery - Supercapacitor
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Simulation of the system
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Performance Parameters
• Reducing of RMS-current
• Reducing of power losses in battery
• Total energy efficiency
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Load Cycle (ECE15-L)
• Acceleration
• Constant velocity
• Regenerative braking
0 20 40 60 80 100 120 140 160 180 200-25
-20
-15
-10
-5
0
5
10
t[s]
P[W/kg]
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0 10 20 30 40 50 60 70 80 90 100-4000
-3000
-2000
-1000
0
1000
2000
t[s]
P[W]
EC PowerLoad PowerBattery Power
Control Strategy
• Low pass filtering
• Braking energy to EC
• Loading of EC
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Control Strategy
• Low pass filtering
• Braking energy to EC
• Loading of EC
0 10 20 30 40 50 60 70 80 90 100-4000
-3000
-2000
-1000
0
1000
2000
t[s]
P[W]
EC PowerLoad PowerBattery Power
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Test System
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Test System• EC
10 units 2.5V, 2600F /28 units 2.0V, 2700F
• Battery 50V / 100V, 60Ah NiMH
• DC/DC160 kW, 330A 2-quadrants DC/DC converter
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Results - simulations and experiment
• Battery, 100V
• EC, 56V
• Equal to car with the weight of 250 kg
0 20 40 60 80 100 120 140 160 180
-6000
-5000
-4000
-3000
-2000
-1000
0
1000
2000
3000
4000
t[s]
P[W]
Load Power Sim.Load Power Exp.Battery Power Exp.Battery Power Sim.
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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 %
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Example-Simplified system for a city bus, 220kW
Battery 310 kgEC 280 kgDC/DC 90 kg
Total weight 680 kg
NiMH-battery + EC
Battery 1150 kgDC/DC 45 kg
Total weight 1195 kg
NiMH-battery
Weight reduction: 43 %
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Conclusions
Drawbacks Advantages• Weight reduction• Improved battery lifetime• Reduced temperature
dependency• EC could replace batteries
• Complexity• Difficult to estimate
the price• Not tested in full scale