Interpretation of the Particularities of Lithium-Ion Capacitors and Development of a Simple Circuit Model

The expeditious development of electric vehicles and hybrid electric vehicles relies on using appropriate energy storage systems such as supercapacitors and lithium-ion batteries. The new technology that combines both conventional energy storage systems is the lithium-ion capacitor. The aim of this component is to fill the gaps between supercapacitor's low energy density and lithium-ion battery's low power density. This paper presents the main electrical characteristics, deduced from frequency domain measurements, of such a technology. The nonlinear capacitance evolution of a lithium-ion capacitor cell with respect to the voltage was analyzed based on its physicochemical properties. Moreover, the lithium-ion capacitor was modeled using a simple model derived from the frequency measurements.