Hybrid battery–supercapacitor system for full electric forklifts

Abstract

Despite the yearly rise in the market quota of full electric vehicles, the main limitations on the deployment of electric vehicles are the real performances of the battery storage during operation. In this study, the authors focus on hybrid electrical storage systems composed of lead acid batteries and supercapacitors. Two different coupling methods are investigated: (i) the direct parallel coupling of the two storage devices and (ii) coupling by means of a step-up converter between the supercapacitor bank and direct current (DC) link of the entire power-train, where lead acid batteries are also connected. A specific control strategy is proposed and implemented in the step-up converter to guarantee the correct power management of the power train and in particular: (i) to save the power request to the lead acid battery pack, (ii) maintain an adequate state of charge of the supercapacitor bank, and (iii) guarantee an adequate voltage level on the DC link. A prototype of the hybrid battery, integrating the proposed control technique, was realised and tested on a real forklift. The performances of the entire power-train were experimentally measured in a warehouse test cycle emulating a typical daily working cycle.

A Review on Power Electronics Technologies for Electric Mobility

“…At the energy storage level, in [322] is presented the design and control of a phase-shift full-bridge isolated dc-dc converter for the on-board EVBC of an electric forklift. Hybrid energy storage systems for electric forklifts are presented in [323] based on batteries and ultracapacitors, in [324] based on batteries and fuel cells, and in [325] based on fuel cells and ultracapacitors, using no standard batteries. An electric energy recovery system for an electro-hydraulic forklift is studied in [326].…”

“…for electric forklifts are presented in [323] based on batteries and ultracapacitors, in [324] based on batteries and fuel cells, and in [325] based on fuel cells and ultracapacitors, using no standard batteries. An electric energy recovery system for an electro-hydraulic forklift is studied in [326].…”

Sizing of Lithium-Ion Battery/Supercapacitor Hybrid Energy Storage System for Forklift Vehicle

“…The higher the current, the higher the heat loss that will occur in the internal resistance of the battery. However, heat is one of the critical ageing factors [11,21,22,56,57]. Therefore, by decreasing the RMS battery power, battery lifetime can be improved.…”

“…However, for indoor applications and Industry 4.0 requirements, zero-emissions is mandatory. Therefore, electrical forklifts are widely used these past few years [10,11]. They also provide very high torque, low speed and zero noise pollution thanks to the electric motor [11].…”

Characterization and Model Parameters of Large Commercial Supercapacitor Cells

“…For these reasons, they found a wide range of applications in transportations, in industrial systems and in electric power grids. In particular, SCs are exceptionally effective when repetitive pulsed power is required [3], [4]- [5]. Furthermore, the integration of SCs into hybrid solutions, like their combination with energy-intensive sources as lithium-ion batteries, appears as the potential key approach for future flexible and cost-effective energy storage devices or systems [1], [4], [6]- [9].…”