Electric energy storage is the key enabler for improvement of the demand side energy management and integration of renewable energy into grid.This paper analyzes the development situation and the problems urgently needed to be solved in the field of physical energy storage technologies such as pumping energy storage, compressed air energy storage and flywheel energy storage.More importantly, a detailed discussion is made on the working principles, technical advantages as well as the applications and challenges of electrochemical energy storage technologies, including lithium ion battery, lead carbon battery, flow battery, sodium sulfur battery( ZEBRA battery) and liquid metal battery.This paper offers some references for the development of electric energy storage technologies.