© 1999 Robert A. Freitas Jr. All Rights Reserved.

Robert A. Freitas Jr., Nanomedicine, Volume I: Basic Capabilities, Landes Bioscience, Georgetown, TX, 1999

6.2 Energy Storage

For medical nanorobots, onboard volume is a precious and limited commodity. Viscous forces dominate inertial and gravitational forces, so mass is almost irrelevant. Hence energy stored per unit volume (joules/m³) is an appropriate figure of merit for nanoscale energy storage devices.

Energy storage devices may be required to maintain temporary power during subsystem failures, metamorphic transitions, or during temporary unavailability of environmental energy resources; to provide supplementary supplies during brief periods of overcapacity consumption; or to buffer normal energy usage among subsystems generating large fluctuations. Stored energy may also be used to power short-lived medical nanodevices on missions of limited duration. For example, a 1 micron³ storage device with storage density of 2 kT/nm³ (~10⁷ joules/m³) contains sufficient energy to power a 10 picowatt (pW) nanorobot for ~1 second. Chemical storage devices (providing up to 10¹¹ joules/m³; Section 6.2.3) may extend this duration to 10⁴ sec (~3 hours).

Last updated on 18 February 2003