Electrical energy storage is a central element to any electric-drive train technology, whether hybrid-electric, fuel-cell, or all-electric. A particularly cost-sensitive issue with energy storage is the high replacement cost of depleted battery banks. One possibility to ease the power burden on batteries and fuel cells is to use ultra-capacitors as load-leveling devices. In this overview the technology and difficulties of ultracapacitor-Battery interface for energy management system is analyzed and the related esearch work is made. research work is made.