Defense Intelligence Reference Document Ultracapacitors As Energy And Power Storage Devices

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AEROSPACE
Ultracapacitors are suitable for applications requiring large bursts of power for relatively
short periods of time, with the ability to be recharged rapidly. Ultracapacitors are
finding ubiquitous use in electronics and transportation, and there are a number of
applications in aerospace ranging from backup power to high pulse-power delivery. The
electronics systems in military vehicles require failsafe operation; ultracaps can be
designed to provide a continuous power source in the event of a power interruption.
Fire-control systems are another example where continuous power is required,
including higher power capability. Airbags require a backup power source to ensure
they are deployed as required with or without a powered system. Small portable
communications systems have ultracaps for backup power and to retain memory.
Memory retention is critical in many systems; for example, the bridge power used
during a transfer from ground to onboard power in aircraft systems can be supplied by
an ultracap. Ultracaps are excellent for stabilizing the power that is either delivered or
received. For example, communication systems may require additional power during
transmission, which can be offset by using an ultracap to supplement the system. Bus
voltages may need peak current stabilization.
The high-power capabilities of ultracaps make them advantageous for several systems.
The fast discharge is ideal for delivering the significantly higher power required for
starting cold engines. Active suspension systems in vehicles require bursts of power
that are delivered in response to the terrain; an ultracap can store the necessary power,
deliver as necessary, and recharge quickly. GPS-guided missiles and projectiles may
use ultracapacitors to provide the power required for communication and navigation.
High-power discharge for naval systems has been identified as an area where ultracaps
are especially useful, often used in hybrid systems in tandem with high-energy
batteries. Extremely high power delivery makes ultracapacitors a potential vehicle for
delivering the power required for directed-energy weapons. As pseudocapacitive
systems reach higher energy densities, along with improvements to the materials and
cell composition, ultracapacitors will have capabilities of delivering large amounts of
power in a very short time, contained within an increasingly smaller footprint.
Signatures and Vulnerabilities
As mentioned above, ultracapacitors could be important in the development of
ultrawideband energy weapons. Previously, this market has been dominated by bulk
acoustic semiconductor switch (BASS) devices, but by stringing several capacitors
together in parallel, a more formidable discharge can be created. Because
ultracapacitors have very high discharge rates, they will emit a distinctive broadband RF
signature when discharged. A modest wideband receiver may be able to detect this
discharge; its proximity will depend upon the construction of the target device.
Furthermore, the architecture of such a device may yield a unique signature that, with
the proper equipment, can be identified and certainly warrants further study. When
employed in a particular electronic device, this signature may be altered by its
immediate environment, and this may further give an indication of both the type of use
and device employed. When searching for ultracaps in the field that are not in use, the
large electrostatic potentials may provide a clue.
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