Efficiency of SuperCap storage in energy harvesting micropower supplies

Abstract

Energy accumulators are useful storage components in energy scavenging IoT devices. In cases of intermittent energy scavenging, electrical energy is stored in such components for later use. Most used energy accumulators are batteries and supercapacitors. EDLC supercapacitors store less energy than lithium-based batteries, but their charge/discharge limit reaches up to half a million cycles. However, due to self-leakage currents, the usable energy stored in an EDLC is difficult to estimate and varies with time. In this paper, we provide practical observations concerning the efficiency of such devices in IoT systems with energy scavenging and provide energy capacity estimations vs baseline energy storage calculations.