Abstract

On the path to a low-carbon future, advancements in energy storage seem to be achieved on a nearly daily basis. However, for the use-case of sustainable transportation, only a handful of technologies can be considered, as these technologies must be reliable, economical, and suitable for transportation applications. This paper describes the characteristics and aging process of two well-established and commercially available technologies, namely Lithium-Ion batteries and supercaps, and one less known system, flywheel energy storage, in the context of public transit buses. Beyond the obvious use-case of onboard energy storage, stationary buffer storage inside the required fast-charging stations for the electric vehicles is also discussed. Calculations and considerations are based on actual zero-emission buses operating in Graz, Austria. The main influencing parameters and effects related to energy storage aging are analyzed in detail.Based on the discussed aging behavior, advantages, disadvantages, and a techno-economic analysis for both use-cases is presented. A final suitability assessment of each energy storage technology concludes the use-case analysis. Document type: Article

Abstract

Carbon fibre reinforced composite materials show potential as energy storage components, due to the high electric conductivity of the carbon fibre. Supercapacitors store electrostatic energy over the electrode surface. Increasing the surface area of electrodes based on carbon fibre could lead to an increase in storage capacitance.

Different methods to increase surface area of carbon fibre are studied with the aim of increasing energy storage capacitance of the fibres working as electrodes for structural electrochemical capacitors. Surface modification was carried out by the deposition of carbon nanoparticles (GNP) and porous carbon (CAG). Effectiveness of the different methods was analysed by measurements of BET surface area and microscopy characterisation. The effect on mechanical properties of individual fibres was analysed and storage capacitance was measured by electrochemical characterisation.