Electrical Energy Storage Technologies for Hybrid Electric Aircraft 2018-01-1938
Hybrid electric propulsion has been widely proposed as a solution to meet challenging emissions, noise and fuel burn targets for future aircraft. However, the development and design of the electrically driven propulsion system on these aircrafts is extremely challenging due to the nature of the application and the need for a resilient electrical power system (EPS) which meets power density criteria. In a particular the EPS must deliver continuous electrical power to propulsion motors.
Whilst the primary source of electrical power for hybrid electric propulsion will be from gas turbine driven electrical generators, energy storage systems (ESS) are expected to be key to optimising the performance of the EPS. To date, the role of energy storage in hybrid electric aircraft EPS has not been fully explored. Whilst a number of different ESS technologies are either available, or expected to be available for selected entry into service (EIS), the down-selection of appropriate ESS technology is highly dependent on the role that ESS will play in a hybrid electric propulsion aircraft.
The utilisation of ESS in other applications (rail, marine and land-based grid) is well established, and hence provides the platform to explore the operation of ESS on a hybrid electric aircraft. This paper will investigate the role of power-dense ESS and energy-dense ESS for hybrid electric aircraft and will consider the option of multiple ESS systems with different roles on a single aircraft EPS platform. It will explore the trade-off between ESS and alternative methods of extra redundancy as a means to provide the necessary availability of supply to the critical electrical propulsion loads, identifying key factors and corner points of the design space. The paper will then provide operational requirements for each of the identified ESS roles, match candidate technologies against these and review the unique design challenges faced with the integration of ESS into the aircraft EPS.
Iain Robert George Fleming, Patrick Norman, Graeme Burt, Catherine E. Jones
University of Strathclyde, University of Stellenbosch
Aerospace Systems and Technology Conference