Peukert's Law for Lithium-ion Capacitors With Constant Power Loads

This paper examines Peukert's law for lithium-ion capacitors (LICs) during constant power discharge processes. Peukert's law is a relationship originally developed to characterize the charge delivery capability of lead-acid batteries: when a higher discharge current is applied, less charge is released. As a hybrid energy storage technology, a LIC is normally composed of a graphite negative electrode typically used in lithium-ion batteries and an activated carbon positive electrode usually used in supercapacitors. To evaluate the LIC technology for potential aerospace applications, this paper investigates the LIC energy delivery pattern when a constant power load is applied. By performing extensive experiments, this paper verifies that Peukert's law applies to LICs in the power mode: when the applied discharge power decreases, more energy is delivered. Furthermore, this paper studies the LIC Peukert constant dependence on its terminal voltage. Experimental results suggest that this dependence is similar to that of supercapacitors.