Batteries and supercapacitors – an equivalent circuit comparative study
Abstract
Using more renewable power is necessary to reach the sustainability goals set by the UnitedNations and reducing greenhouse gas emissions. Increased use of renewable energy is alsorequired as many different sectors need to be electrified. Furthermore, the war in Ukraine hasshown that relying on a foreign state’s energy supply to guarantee enough power is not aviable strategy, and that more locally produced energy is needed. In order to achieve theseambitions, it is necessary to be able to store energy. Subsequently, both efficientsupercapacitors and batteries are needed.In this thesis a review of batteries and supercapacitors were carried out. First a short literaturereview was performed to see where batteries and supercapacitors are being used and howthey perform. A second literature study was performed to study the modelling of batteriesand supercapacitors. Equivalent circuit models for both batteries and supercapacitors weremade. Two different batteries and supercapacitors were chosen for simulations. The batteriessimulated were based on lithium ion and NiMH technology. The supercapacitors were chosenfrom two popular brands; Nichion and Eaton. The parameters for the different devices weredecided by assuming that they behaved the same way as found in other studies in theliterature. The devices were then simulated using a resistive load for a discharge cycle. Longrangesimulations using CC-CV profiles were used.Simulations showed that batteries were able to provide a charge for a longer time comparedto the supercapacitors during discharging on a resistive load. During the CC-CV long-rangesimulation the Eaton 400F supercapacitor had the highest power output. Both supercapacitorswere able to accomplish more cycles than both the batteries. The NiMH was able to do ½ cyclemore than the lithium battery. The SOH calculations showed that the Nichion supercapacitorwas able to achieve the most cycles. The lithium battery was able to perform more cycles thanthe NiMH battery.