The advancement of the rechargeable battery technology is an essential approach to overcome the global warming issue. Large-scale batteries, such as Na-S battery and redox-flow battery, are expected to be installed in recently developed large scale systems such as electric vehicles, renewable energy storage, and smart grids. Owing to their high-energy density, rechargeable lithium-air batteries attract great deal of attention, and expected to be used for the next generation energy storage systems. In this paper, basic concepts and technological challenges of those battery systems are reviewed and discussed.

　Lithium ion batteries have higher energy density. Recently, lithium ion batteries are beginning to be utilized in industrial applications. As for the lithium ion batteries in industrial applications, many different performances are required as well as energy density. It is important to develop according to the own requirement for their application. Energy density of Lithium ion batteries using LTO anode is smaller than that of conventional ones. But the batteries with LTO anode have unique features. In this reports, the features and application of lithium ion batteries using LTO anode is explained.

　The flywheel energy storage systems (FESS) can be stabilized the fluctuation of the output of the solar photovoltaic power generation system. FESS has been developed as a joint project of five enterprises subsidized by the New Energy and Industrial Technology Development Organization (NEDO). Key technology of FESS is the high temperature superconducting magnetic bearing (SMB). It consists of high temperature superconducting coils for its stator and high temperature superconducting bulks for its rotor. The FESS demonstration machine was reinstalled in the power plant, and the examination of the charge/discharge with solar photovoltaic power by the FESS demonstration machine was operated.

　We have been developing new Compressed Air Energy Storage System which is trademarked as ”CAB”. The CAB -Compressed Air Battery- is the machine type battery which is expected to be used for short-time load leveling in the grid-connected operation of wind-farm and mega-solar power generation, and for peak cutting of power demands for factories and buildings. By using screw type compressors and turbines, it can be possible to follow frequent load leveling against renewable energy compared with turbo and reciprocating machineries that have difficulties in part load operation or rapid change of speed. The features of CAB system, equipment configuration, system efficiency, and characteristics of charging/discharging are mainly introduced in this paper as clean power energy storage system used compressed air.

　Electric double layer capacitor is a suitable energy storage device for automotive applications, because it has unique characteristics, which are high rate capability, good low temperature and long cycle life, in comparison with other devices such as rechargeable batteries. The present paper describes a principle, constitution, characteristics and performances of electric double layer capacitor and also Nippon Chemi-Con's low resistance electric double layer capacitor called DLCAP^TM DXE series.

　Wireless power transmission technology can be a simple and frequent high power, such as 300kW, charging measure to the energy storage device onboard railway vehicle. In this application, higher reactive power should be cared due to the long gap between primary coil and secondary coil on the coils design. Switching loss of the power converters should be looked after by the less switching frequency and zero current switching (ZCS) technologies. In this paper, the author introduces the design method of the coils with less reactive power and presents one of experimental results of a power control method with ZCS technologies by means of scale down experimental model.

　Typically, the difference between electromagnetic induction and magnetic resonant coupling is ambiguous. However, these two technologies are seamlessly connected. In this paper, the superiority of magnetic resonant coupling over electromagnetic induction, as well as the magnetic flux distinctive features, are demonstrated and discussed by comparing four circuit topologies. It is shown that only the S-S topology can achieve both high power and maximum efficiency and that the magnetic flux possesses unique characteristics.

　The magnet arrangement of the concentrated flux IPM motor, that concentrates the magnetic flux from the magnet at the air gap, was considered. A prototype motor was experimentally manufactured and evaluated. In this study, it is confirmed that the proposed concentrated flux IPM motor can achieve a torque which is twice that of the existing SPM motor. The problems with manufacturing is identified and the measures to counter those is considered.

　To eliminate microwave reflections from a rectangular antenna element used to irradiate liquid objects with microwaves, the element needs to be designed optimally. Two design parameters: relative permittivity and thickness of the antenna, were used in the optimization, the objective function to be minimized being power reflection coefficient of the microwaves. An applicable range of relative permittivity for the liquid objects was identified. The characteristics of the antenna were checked in numerical simulation and experiments using water. Also the temperature dependencies of the antennas with existing material were checked in both numerical and experimental tests.

　Co-rich Co-Fe alloy is known to possess of high saturation magnetostriction, high Curie temperature and good mechanical property. In this study, the rapidly solidified Co₇₅Fe₂₅ alloy were studied for appearance further large magnetostriction due to change in both of the structure and the texture by a combination of heat treatment and cold-rolling. The Co-Fe alloy ribbons were produced by a single Cu-roller rapid solidification, and subsequently annealed at 973-1023K for 1h in vacuum atmosphere after rolling. For evaluation of the heat treatment effect and the rolling effect, magnetic properties such as magnetization, coercivity, magnetostriction and susceptibility were measured as well as crystal structure. As a result, enhancement of magnetostriction improved due to combination of cold-rolling and annealing because precipitating appearance of fcc phase decreased, and also magnetostrictive susceptibility improved caused by enhancement of magnetostriction reached to about 2 times. Additionally the coercivity of annealed specimens after rolling showed a decreasing tendency compared with that of without rolling.