A review of developments in energy storage systems for hybrid excavators

Hybrid technology applied to vehicles and construction machineries is one of the promising technologies to address environmental challenges. The energy storage system with higher power density, higher energy density, small size, long lifetime and low cost is essential for the hybrid system. This paper firstly analyzes the difference among the energy storing elements especially for battery and super capacitor (SC). Secondly, the advantages and disadvantages of different structures of energy storage systems are analyzed and compared. Thirdly, the energy storage systems and control strategies in hybrid excavators designed by different manufacturers and research institutions are analyzed in detail. Finally, the challenges in the energy storage system of hybrid excavators are discussed.