Methods for Determining the Leakage Current of Supercapacitors

Abstract

Supercapacitors or Electrochemical Double Layer Capacitors (EDLC‘s) have become increasingly used in nowadays applications, for example in the automotive industry. This passive electronic components category, due to their advantages, has been compared to conventional batteries which present a particular interest such as the high number of charge/discharge cycles, low charging time, sustaining high charge/discharge currents and so on. Alongside these advantages they have a series of disadvantages that cause, for users, to become reluctant in using them in different applications. Thus, the relative high values of equivalent series resistance (ESR) and the leakage current, as results of the supercapacitor self-discharge, compared to the batteries, represent disadvantages of the EDLCs. Several aspects regarding the equivalent series resistance (ESR), in a previous paper [1], were determined through various methods. The present paper will focus on the leakage current investigation at different temperatures in a large range of temperature values (from −20 °C to +70 °C). It is important to monitor the variation of this parameter with temperature in order to evaluate the supercapacitors loss and identify how the supercapacitor influences the behavior of the circuit in a certain application, especially taking into consideration that supercapacitor data sheets do not contain such information.