Electrical Energy Storage to Meet Evolving Aircraft Needs

The value of “ultracapacitors” (also referred to as “supercapacitors” or “electric double layer capacitors” in some literature) as an augmentation device when placed in parallel with “electrochemical” energy storage (i.e. battery) is presented in this paper. Since ultracapacitors possess unique attributes due to their higher value of energy storage density (or Joules/WattHrs per mass) compared to conventional capacitors while maintaining the peak power providing capability (to some degree) typical of conventional capacitors they may provide a near term solution in applications demanding longer battery operating life when placed in parallel. Such demands may be pronounced by the onset of More-Electric-Aircraft peak loads and “cold-crank” Auxiliary Power Unit (APU) electric-starting in demanding cold temperature environments.

The potential benefits of an ultracapacitor in parallel with a battery will be illustrated through a very simple lab demonstration as well as a more complex system consisting of a large motor inrush load (cold-cranking condition) through the use of a computer simulation tool (Simulink). In addition to the ultracapacitor discussions and demonstration, other forms of advanced energy storage will be reviewed for their potential near or long term application in meeting the evolving needs of More Electric Aircraft as presented at the 2011 International Double Layer Capacitor and Hybrid Energy Storage Seminar in Deerfield Beach Florida (Reference 3).