Development of Grid-stabilization Power-storage System with Lithium-ion Secondary Battery

Mitsubishi Heavy Industries, Ltd., (MHI) is developing a large-capacity lithium-ion secondary battery in a joint effort with Kyushu Electric Power Co., Inc. Although a conventional battery of this type offers both the advantages of large capacity and long life, internal resistance causes the battery temperature to increase while charging or discharging at a high current. Thus, the charge and discharge rates are limited when the battery is used in the grid-stabilization power-storage system of a renewable-energy source (such as wind power or photovoltaic power). We have optimized the battery materials and design to lower the internal resistance, and have obtained a battery that permits 2C charge and discharge. Furthermore, we have developed a 100-kWh-class grid-stabilization power-storage unit, enabling a rated operation of 100 kW, by connecting these batteries in series and in parallel.