Susceptibility of “Ultracapacitors” to Proton and Gamma Irradiation - Maxwell Technologies - #1

Susceptibility of "Ultracapacitors" to Proton and

Gamma Irradiation

S. Shojah-Ardalan, R. Wilkins,H. U. Machado, B. A. Syed, S. McClure, B. Rax, L. Scheick, M. Weideman, C. Yui, M. Reed and Z. Ahmed

applications, hybrid electric vehicles, power generation plants, commercial electric vehicles and racecars. Ultracapacitors are good candidates for space applications in remote or stand­alone systems where the primary power source is provided by a battery, a fuel cell, or solar cell arrays.

The Technologies Assurance group at JSC conducted performance tests on ultracapacitor samples along with electrical and mechanical screening. These tests included visual inspection, fine leak test, accelerated life test, static burn-in, reverse bias test, self heat test via rapid charge­discharge, over voltage pulse, thermal shock and destructive physical analysis. The tests demonstrated that the device was suitable for the intended applications in the ISS electrical portable systems. However, no data is available on the reliability of the component and its performance in an ionizing radiation environment.

We have conducted a series of electrical tests before, during, and after gamma irradiating these devices with a ⁶⁰Co source and 60 MeV proton radiation. These tests were performed to characterize the electrical parameters of the ultracapacitors and examine any possible changes in their charge/discharge ability in a radiation environment. This electrolytic capacitor uses an electrolyte consisting of tetraethylammonium tetrafluoroborate, dissolved in acetonitrile solvent. To our knowledge no previously data has been obtained about the interaction of gamma or proton radiation with this electrolyte or individual component.

II. Experimental Procedure

Electrical characteristics testing was conducted to measure the capacitance (C) and equivalent series resistance (ESR) of the devices as specified by the manufacturer. Three different ultracapacitor models: PC10 (10Farad), PC100 (100Farad) and PC1000 (1200Farad) from Maxwell Technologies were selected. Pre- and post-radiation electrical testing were performed on four samples from each category.

The tests were performed according to the manufacturer's recommended procedures [1].

The charging current was monitored on the power supply. Voltage and current were occasionally measured using another multi-meter (shown as voltmeter in Fig.1) to verify power supply parameters.

I. Introduction

The "Ultracapacitor" is a commercial-of-the-shelf (COTS) energy storage component [1] having low internal effective series resistance and high capacitance. The technology is especially suited for applications where a large amount of power is needed for fractions of a second to several minutes. Ultracapacitor can provide high peak currents to loads while the power source provides steady state power. Using the ultracapacitor in this manner will reduce the power source volume and will prolong the power source life. The ultracapacitor can be charged and discharged indefinitely for the life of the system. They are already in use for military

Manuscript received February 7, 2003. This work was supported in part by the NASA Grant No. NCC 9-114.

Shojah Shojah-Ardalan is with the NASA Center for Applied Radiation Research, Prairie View A&M University, Prairie View TX 77446 (telephone: 936 857 4606, email: s_ardalan@pvamu.edu).

Richard Wilkins is with the NASA Center for Applied Radiation Research, Prairie View A&M University, Prairie View TX 77446 (telephone: 936 857 4606, email: r_wilkins@pvamu.edu).

Henry Machudo was with SAIC, Technology Assurance Group, NASA Johnson Space Center, Houston TX 77058.

Bashir Syed was with SAIC, Technology Assurance Group, NASA Johnson Space Center, Houston TX 77058 (email: bsyed@worldnet.att.net).

Steve McClure is with NASA Jet Propulsion Laboratory, Pasadena CA 91109 (telephone: 818 354 0482, email: Steven.S.Mcclure@jpl.nasa.gov).

Bernard Rax is with the NASA Jet Propulsion Laboratory, Pasadena CA 91109 (telephone: 818 354 9799, email: Bernard.G.Rax@jpl.nasa.gov).

Scheick Leif is with the NASA Jet Propulsion Laboratory, Pasadena CA 91109 (telephone: 818 354 3272, email: leif.scheick@jpl.nasa.gov).

Michael Weideman is with the NASA Jet Propulsion Laboratory, Pasadena CA 91109 (telephone: 818 354 1830, email: Michael.C.Wiedeman @jpl.nasa.gov).

Candice Yui is with the NASA Jet Propulsion Laboratory, Pasadena CA 91109 (telephone: 818 393 0945, email: Candice.C.Yui@jpl.nasa.gov).

Mac Arthur Reed was with the NASA Center for Applied Radiation Research, Prairie View A&M University, Prairie View TX 77446 (telephone:

936 857 4606).

Zaheerudin Ahmed is with the NASA Center for Applied Radiation Research, Prairie View A&M University, Prairie View TX 77446 (telephone:

936 857 4606).