Evaluating the Performance of Hybrid Ultra Capacitor (HUC) based Hybrid Energy Storage System (HESS) for Electrical Forklift application

Abstract

Historically, mobility and fossil fuels are highly interlinked, however Electric Vehicles (EV) are gaining prominence in the last few decades because of global factors like Climatic change, Advances in renewable energy, Rapid urbanization, GPS enabled Data capture and analysis, Improvements in Battery chemistry, geopolitical issues in Energy security, etc. [1]. At present batteries are dominating the storage technology of electric vehicles, however due to the challenging power demands of the urban driving cycles, batteries face accelerated deterioration. To compensate for the loss, manufacturers tend to oversize the batteries at the expense of additional cost and weight. Researchers have observed that battery life can be increased significantly by smoothening the battery charging and discharging currents [2] . Hence Electric vehicle manufacturers worldwide have incorporated several variations of Hybrid Energy Storage System (HESS) with combinations of conventional Internal Combustion Engine (ICE), Fuel cells, Batteries, Ultra Capacitors (UC), etc. intending to decouple the high power and high energy demands and assign them to separate sources. In this study, an electrical forklift that runs with the lead-acid battery as its Energy Storage System (ESS) was considered. Hybrid Ultra Capacitor (HUC) banks were integrated with a lead-acid battery pack similar to that of the forklift and the performance of the HESS was studied for the forklift application. It was observed that HUC banks help in smoothening the battery current thereby helps in increasing the battery life.