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This Defense Intelligence Reference Document from the Defense Intelligence Agency, dated 1 November 2010, was one of a series of advanced technology reports produced in FY 2010 under the Advanced Aerospace Weapons System Applications (AAWSA) Program. It reviews ultracapacitors as energy and power storage devices. It covers how they work, their materials, their commercial and military uses, and new developments such as carbon nanotubes, thin films and magnetic capacitors. It concludes that the U.S. government must understand and adopt advanced ultracapacitors.
“The Advance”13 pages
UNCLASSIFIED//F811. 8FFl!lllit 1!1!11!! t!IHL I Act1vc1tccJ carbon electrodes Electrolyte Ac:t1vc1tcci cc1rbon electrodes 0000000000 Separcitor SOclked Ill electrolyte 0000000000 Material selection and construction ■ EIPC tmdf'~ ■ Scpdrcltor ■ Flccrr-olytr ■ Wound lU/llfJU/lt'l"lt ■ C1sr Figure 2. Operation of an Ultracapacitor. A simple ultracapacitor ut111zes two similar electrodes (typically carbon) with a separator and electrolyte to create the electrochemical double layer that governs operation. 7 BATTERIES AND ULTRACAPS For an ultracapacitor, energy is stored within the electrical double layer, which is a physical storage mechanism. Contrast this with batteries, where charge and discharge take place through a chemical (Faradaic) reaction. Since charge is stored physically, there is no direct degradation mechanism that limits cycle life. Side reactions do occur, which prevents infinite cycle life, but ultracaps can often be cycled tens of millions of times. 8 Batteries store their energy through chemical reaction; consequently, cycle life is much shorter and heavily dependent on the depth of discharge. In contrast, there are no limitations to the discharge depth with an ultracapacitor. Table 1 addresses some of the general characteristics of batteries and ultracapacitors, which can help to determine the preferred system for a specified application. The values are based upon 2008 data, so some numbers are outdated, but the relative values remain consistent. There are now hybrid devices that blur the boundaries further by introducing a battery-like electrode to replace one of the two identical electrodes in a traditional ultracapacitor. 3 UNCLASSIFIED//Flilll. lilFFUil,t.k l.lli&i lil'lk>/
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 34 pages are in the text index: search them above, or from the library's search.