Material characteristics and the performance of electrochemical capacitors for electric/hybrid vehicle applications
- Univ. of California, Davis, CA (United States). Inst. of Transportation Studies
- Idaho National Engineering Lab., Idaho Falls, ID (United States)
Electrochemical capacitors (ultracapacitors) are one approach to meeting the high power requirements for the energy storage system in an electric vehicle.Energy is stored in an electrochemical capacitor by charge separation in the double layer formed in the micropores of a very high surface area electrode material, which does not undergo chemical change as in a battery. Consequently, the material requirements for capacitors are very different from those of batteries. In the last several years, a number of promising material technologies have been identified for use in electrochemical capacitors. These include activated carbon fibers, foams, and composites, doped conducting polymers, and mixed metal oxides. In addition to high specific capacitance, the electrode material must also have a low electronic resistivity (< 0.1 {Omega}-cm) in order that charge can be distributed with minimum voltage drop in the electrode. Electrochemical capacitor cells have been fabricated using the various material technologies with both aqueous and organic electrolytes. Tests of the cells have shown near ideal charge/discharge characteristics--that is, the voltage versus time curves are nearly linear for constant current tests. The energy densities of 1 V cells, using aqueous electrolytes, are 1 to 1.5 W {center_dot} h/kg and those of 3 V cells, using organic electrolytes are 7 to 10 W {center_dot} h/kg. Most of the cells have high power densities of 1 to 3 kW/kg. Numerous new materials for electrochemical capacitors have been identified, processed, and tested in electrodes and cells in recent years and progress is rapid in this relatively new field of research.
- OSTI ID:
- 162940
- Report Number(s):
- CONF-950412-; ISBN 1-55899-296-0; TRN: IM9604%%44
- Resource Relation:
- Conference: Spring meeting of the Materials Research Society (MRS), San Francisco, CA (United States), 17-21 Apr 1995; Other Information: PBD: 1995; Related Information: Is Part Of Materials for electrochemical energy storage and conversion -- Batteries, capacitors and fuel cells; Doughty, D.H. [ed.] [Sandia National Labs., Albuquerque, NM (United States)]; Vyas, B. [ed.] [AT and T Bell Labs., Murray Hill, NJ (United States)]; Takamura, Tsutomu [ed.] [Rikkyo Univ., Tokyo (Japan)]; Huff, J.R. [ed.] [Ballard Power Corp., Albuquerque, NM (United States)]; PB: 463 p.; Materials Research Society symposium proceedings, Volume 393
- Country of Publication:
- United States
- Language:
- English
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25 ENERGY STORAGE
HYBRID ELECTRIC-POWERED VEHICLES
CAPACITORS
MATERIALS
CARBON FIBERS
FOAMS
COMPOSITE MATERIALS
POLYMERS
DOPED MATERIALS
OXIDES
CAPACITANCE
ELECTROLYTES
ELECTRIC CHARGES
ELECTRIC DISCHARGES
ENERGY DENSITY
POWER DENSITY
SERVICE LIFE
ELECTRODES
EXPERIMENTAL DATA