Recent DOE Sponsored Electrochemical Capacitor Test Results

1999 ◽  
Vol 575 ◽  
Author(s):  
R. B. Wright ◽  
T. C. Murphy ◽  
D. K. Jamison ◽  
S. A. Rogers
Keyword(s):  
High Power ◽  
Electrochemical Capacitor ◽  
Fast Response ◽  
Department Of Energy ◽  
Constant Current ◽  
Specific Power ◽  
Equivalent Series Resistance ◽  
Test Results ◽  
Constant Power ◽  
Energy Products

ABSTRACTElectrochemical capacitors (ultracapacitors) are being developed for hybrid vehicles as candidate power assist devices for the fast response engine and for other energy storage systems that can utilize the high power densities available from these devices. Ultracapacitors show promise toward being able to accept high regenerative pulses and high power delivery capabilities while exhibiting very high cycle life. This paper will present recent test data from two U.S. Department of Energy (DOE) supported ultracapacitor projects designed to meet the fast response engine requirements. Constant-current and constant-power test results will be presented that have been acquired from recent prototype capacitors supplied by SAFT America, Inc. (ten devices), and Maxwell Energy Products, Inc. (two devices). The SAFT capacitors are rated at 0.5 V to 3 V with capacitance ratings ranging from 135 F to 138 F. Capacitor cells rated at 2.3 V and 101.4 F were also evaluated that were produced by Maxwell Energy Products, Inc. Both sets of devices used proprietary carbon electrodes with non-aqueous electrolytes in their design. From the constant-current discharge tests, the discharge current dependence of the capacitance, equivalent series resistance, and RC-time constant were determined as well as the capacitors’ voltage dependence of the capacitance. Constant-power discharge tests permitted the specific energy as a function of the specific power to be determined, and also the discharge/charge round trip efficiency as a function of the magnitude of the constant-power discharge.

scholarly journals Experimental Electrochemical Capacitor Test Results

1997 ◽  
Vol 496 ◽  
Author(s):  
R. B. Wright ◽  
T. C. Murphy ◽  
Susan A. Rogers ◽  
Raymond A. Sutula
Keyword(s):  
Test Data ◽  
Electrochemical Capacitor ◽  
Fast Response ◽  
Department Of Energy ◽  
Constant Current ◽  
Equivalent Series Resistance ◽  
Test Results ◽  
Available Energy ◽  
Energy Products ◽  
New Generation

ABSTRACTVarious electrochemical capacitors (ultracapacitors) are being developed for hybrid vehicles as candidate power assist devices for the Partnership for a New Generation of Vehicles (PNGV) fast-response engine. The envisioned primary functions of the ultracapacitor are to level the dynamic power loads on the primary propulsion device and recover available energy from regenerative breaking during off-peak power periods. This paper will present test data from selected U.S. Department of Energy (DOE) supported ultracapacitor projects designed to meet the fast response engine requirements.This paper will address the temperature dependence of test data obtained from a set of three devices provided from Maxwell Energy Products, Inc. These devices are rated at 2300 F at 2.3 V. Constant-current, constant-power, and self-discharge testing as a function of temperature have been conducted. From these tests were determined the capacitance, equivalent series resistance, specific energy and power, and the self-discharge energy loss factor as a function of the device operating temperature.

Material Characteristics and the Performance of Electrochemical Capacitors for Electric/Hybrid Vehicle Applications

1995 ◽  
Vol 393 ◽  
Author(s):  
A.F. Burke ◽  
T.C. Murphy
Keyword(s):  
Specific Capacitance ◽  
High Power ◽  
Electrode Material ◽  
Voltage Drop ◽  
Chemical Change ◽  
Electrochemical Capacitors ◽  
Electrochemical Capacitor ◽  
Polymer Materials ◽  
Constant Current ◽  
Organic Electrolytes

ABSTRACTElectrochemical 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. The most important material property is its specific capacitance (F/gm or F/cm3). Carbon materials with specific capacitances of 100 to 300 F/gm have been developed. Doped polymer materials having specific capacitances of 300 to 400 F/gm are also being studied. In addition to high specific capacitance, the electrode material must also have a low electronic resistivity ( < 0.1 Ω-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-h/kg and those of 3 V cells, using organic electrolytes are 7 to 10 W-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.

Status Report—Advanced Heat Exchanger Technology for a CCGT Power Generation System

1983 ◽  
Vol 105 (2) ◽  
pp. 348-353 ◽  
Author(s):  
D. E. Wright ◽  
L. L. Tignac
Keyword(s):  
Power Generation ◽  
Heat Exchanger ◽  
Fluidized Bed ◽  
Ceramic Materials ◽  
Department Of Energy ◽  
Test Facility ◽  
Status Report ◽  
Test Results ◽  
Generation System ◽  
Power Generation System

Rocketdyne is under contract to the Department of Energy for the development of heat exchanger technology that will allow coal to be burned for power generation and cogeneration applications. This effort involves both atmospheric fluidized bed and pulverized coal combustion systems. In addition, the heat exchanger designs cover both metallic and ceramic materials for high-temperature operations. This paper reports on the laboratory and small AFB test results completed to date. It also covers the design and installation of a 6×6 ft atmospheric fluidized bed test facility being used to correlate and expand the knowledge gained from the initial tests. The paper concludes by showing the direction this technology is taking and outlining the steps to follow in subsequent programs.

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