Modeling and simulation of photovoltaic powered battery-supercapacitor hybrid energy storage system for electric vehicles

Abstract

Energy storage is crucial for the powertrain of electric vehicles (EVs). Battery is a key energy storage device for EVs. However, higher cost and limited lifespan of batteries are their significant drawbacks. Therefore, to overcome these drawbacks and to meet the energy demands effectively, batteries and supercapacitors (SCs) are simultaneously employed in EVs. A solar photovoltaic (PV) powered battery-supercapacitor (SC) hybrid energy storage system has been proposed for the electric vehicles and its modeling and numerical simulation has been carried out in MATLAB Simulink. The SC is used to supply the peak power demand and to withstand strong charging or discharging current peaks. It also improved the battery pack's durability and extended its life. Different topologies of battery and SC have been explored and their capacity to manage the battery stress is assessed. The passive topology is found to be the most suitable for the proposed model due to its ease of implementation and absence of control scheme. A hybrid topology is used to share the power across batteries, supercapacitors and the PV system. In the proposed hybrid energy storage system, a sudden load on the battery is shifted towards the capacitor and thus, the battery heating is reduced, that ultimately improved the vehicle performance and reduced the charging time. In addition, the supercapacitor stored a lot of energy in a short period of time and delivered more power to the load without experiencing any life-span deterioration. The results indicated that employing a passive DC-DC converter and hybrid energy storage system (HESS) reduced the battery power by 52 %, while the passive HESS system reduced the motor current by 94 %. The supercapacitor also recovered 51 % more energy while starting and can offer peak power more efficiently than a battery.