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This Defense Intelligence Reference Document was prepared by the Defense Intelligence Agency's Defense Warning Office and dated 1 November 2010. It is one of a series of advanced technology reports produced under the Advanced Aerospace Weapons System Applications Program. The report reviews how ultracapacitors work, how they compare with batteries, their history and materials, and their commercial, military and aerospace uses. It concludes that new materials and cell designs will raise energy density and that the U.S. government must understand the devices' spectral signatures.
From the source: Release of 2026-09-18 Incident: 11/1/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys ultracapacitors as high-power energy-storage devices and argues that their main value lies in extremely rapid charge and discharge, very long cycle life, and usefulness in systems that need short bursts of power rather than sustained energy delivery. The report explains how ultracapacitors differ from batteries, reviews the materials and cell designs that determine their performance, and emphasizes that they are especially useful for power stabilization, backup power, load leveling, regenerative braking, and other applications where fast energy transfer matters more than total stored energy. It also notes their drawbacks, including lower energy density, self-discharge, and voltage-management requirements that limit their usefulness as stand-alone replacements for batteries in many applications. The document presents ultracapacitors as a maturing and increasingly important technology whose most credible aerospace and military uses lie in pulsed-power, missile and munitions systems, electric propulsion support, and other hybrid power architectures rather than in long-duration primary energy storage.
UNCLASSIFIED11FOR. 8FFl@IAL tt.!! e"t I Table 1: Contrasting Properties of Batteries and Ultracapacitors9 Characteristic State of the Art Lithium Ion Battery Ultra capacitor Charge time ~3-5 minutes "'1 second Discharge time ~3-5 minutes ~1 second Cycle life 500,000 Specific Energy (Wh/kg) 100-200 5 Specific power (kW/kg) 0.5 -1 5-10 Cycle efficiency (%) 90% 95% Cost/Wh $1-2/Wh $10-20/Wh Cost/kW $75-150/kW $25-50/kW The voltage curve for an ultracapacitor is proportional to the depth of discharge, whereas batteries deliver a relatively constant voltage over a long discharge period. The sloping voltage curve of an ultracap can be advantageous for state-of-charge determinations. However, this is also responsible for the decreased energy density ava ilable in an ultracapacitor. For applications requiring energy to be delivered over a longer time scale or delivered at a constant voltage, the relatively flat voltage curve found in most batteries would be the preferred option. In instances where power is to be delivered or received quickly, or where many cycles are required, an ultracap is ideal. To better understand the differences between batteries and ultracaps, it helps to think of batteries as storing watt-hours of energy and ultracaps as storing watts of power. A Ragone plot illustrates the distinctions by plotting power versus energy in a logarithmic scale. As can be seen in Figure 3, ultracaps make an excellent option where high power density is required. The times shown are rough estimates for a full charge or discharge, which are estimates to help understand the relationship between energy density and power density. Batteries have made significant improvements to power delivery recently, but batteries remain the high-energy-density solution . Ultracapacitors are often thought of as a stop-gap between conventional capacitors and batteries. Recent developments of hybrid capacitors have led to considerable progress toward higher energy density. However, there is a tradeoff between high energy density and high power devices, and the distinctions between the two require consideration of application requirements when choosing the energy storage platform for a system. The differences between ultracaps and batteries do not make the two mutually exclusive. There are applications where either a battery or an ultracap is the preferred energy storage platform. Quite often, these two can be used together in systems to perform complementary roles. UNCLASSIFIEO/;LFOA OFFI&il:.l.b YS& OrtLY 4
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Official release, from the pursue 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.