Peukert’s Law for Supercapacitor Modules: Applicability and Physics

This paper examines the applicability of Peukert’s law to supercapacitor modules and analyzes the underlying supercapacitor physics. Peukert’s law is an empirical relationship originally developed to describe the dependence of the lead-acid battery charge capacity on the discharge current. Recent studies show that Peukert’s law can also be used to characterize the charge delivery capability of supercapacitor cells. Given the relatively low voltage and current ratings of supercapacitor cells, they are usually connected in parallel and/or series in high-power energy storage systems. This paper extends the study of Peukert’s law for supercapacitor cells to supercapacitor modules. After verifying the applicability of Peukert’s law to supercapacitor parallel and series modules, this paper investigates the dependence of the supercapacitor module Peukert constant on voltage and reveals the physical mechanisms accounting for the dependence.