An Overview of Electrical Energy Storage Systems for Automotive Applications

Transcription

1 An Overview of Electrical Energy Storage Systems for Automotive Applications Georg Brasseur, Hannes Wegleiter, Graz University of Technology Alternative Propulsion Systems and Energy Carriers Austrian, European and global R&D- and demonstration projects, research institutions and funding programs Vienna, in cooperation with

2 Roadmap for Different Vehicle Types 2

3 Comparison of Energy Sources Quelle: 29. Int. Motorensymposium, 2008 Ford Motor Company Dr. Gerhard Schmidt 3

4 Ragone Plot for Electrical Energy Storage Systems Data points are determined at 90% charge or discharge efficiency respectively! 4

5 LiIon batteries I Comparison of different cathode types Lithium nickel cobalt oxide Li(Ni,Co)O2, or NCA, is mainly used in cells where the key criteria are high specific energy and long calendar life. 5

6 Pros: LiIon batteries II High specific energy density. Series production / various manufacturer available. Cons: Quelle: Low specific power density. Operating and storage temperature limited. Limited shelf and operational life time. Some components are economically and ecologically questionable. 6

7 63 F, 125 V 102 Wh, 60 kg P = 312 W/kg, Ppeak = 1,562 W/kg E = 1.7 Wh/kg 150 A cont., Ipeak = 750 A, 18 mω Pros: 19 kw 9.4 kw, 14 kw für 26 s Series production, various manufacturer available. -40 C +65 C, Pv = A Supercap High efficiency. High cycle stability. Long life time. High specific power density. Cons: Very low specific energy density. Operating and storage temperature limited. Some components are economically and ecologically questionable. Quelle: products/ultracapacitors/bmod0063-6_low.jpg 7

8 Flywheel Energy Storage I Two solutions for a flywheel energy storage: The flywheel is operated in a vacuum containment at e.g. 100,000 rpm a) Mechanical solution: Mechanically propelled flywheel is coupled to a Continuous Variable Transmission (CVT) that is hydraulically actuated and electrically controlled. Roundtrip efficiency including CVT > 70 % (Flybrid Formula One KERS) b) Electromechanical solution: Fast spinning rotors of two or four reluctance motors. The rotors serve as flywheels and store energy in the inertia of fast spinning armatures (like with the mechanical solution). Charging and discharging as well as the conversion of the mechanical rotor energy to electric energy is done by magnetic fields originating from the stator windings. Roundtrip storage efficiency > 80 % (Compact Dynamics: Dynastore KERS) b) Quelle: a) Quelle: 8

9 Pros: Flywheel Energy Storage II High efficiency: electromechanical > 90 % only mechanical > 80 %. Highest specific power density and average energy density. Operating temperature > 100 C (small radiator volume). High cycle stability (especially with magnetic bearings). Cons: Dynamic controllability of the mechanical solution. Possible problems with noise emission. Only prototypes available, no series production. Flywheel safety: - Debris of a bursting flywheel must be captured - Flywheel stop in case of emergency (e.g. car accident) 9

10 Alternative Energy Storage Pros: High efficiency - Hydraulic Hybrids > 70 % - Electric Hybrids < 25 % Cons: Weight and size Controllability Commun. with the engine ECU From Clean Automotive Technology Efficiencies While Accelerating & Breaking 10

11 Contact Univ.-Prof. Dr. Georg Brasseur Department of Electrical Measurement and Measurement Signal Processing, Graz University of Technology address: TU Graz, Inst. E 438 Kopernikusgasse 24-IV A-8010 Graz, Austria tel: fax: web: georg.brasseur@tugraz.at 11

12 Thank you for your attention!!!!! 12