Mitsubishi Heavy develops containerized large-scale Li-ion energy storage system
Mitsubishi Heavy Industries, Ltd., (MHI), has developed Japan’s first cargo container-type large-capacity energy storage system using Li-ion batteries. The system is capable of providing power of up to one megawatts (MW), and its mobility makes the system suitable for a wide range of applications, including emergency use. The actual system has been installed at the Nagasaki Shipyard & Machinery Works of MHI in Nagasaki Prefecture, Japan, to begin verification testing for a power stabilization system application from early July towards the commercialization of the system.
The container-type “megawatt-class large-capacity energy storage system (ESS)” consists of a 40ft-long container unit, which houses more than 2,000 units of lithium-ion rechargeable batteries, and a 20ft-long container unit, in which two power conditioners are installed. Power conditioners are used for direct current (DC)/alternating current (AC) conversion and their input/output control. Each container unit can be moved by container trailers. The system has a capacity of 408 kWh and is designed to have a system efficiency of 90%.
The power storage system is capable of providing electricity for some 100 households for three to eight hours. By using multiple units of the system, power output can be increased to the level of several tens of thousands of kilowatts.
The system installed for verification testing in Nagasaki is currently being adjusted towards an in-plant electric-load leveling test. Testing will be conducted envisaging such cases as short-cycle conditioning to level fluctuations of electricity generated, including power produced by wind power and solar cells, and medium- and long-cycle conditioning for a period of several hours. It will also test the system for a micro-grid application to enable a stable supply of electricity by storing power from renewable energy, for the use in the areas where connections to regular power transmission/distribution grids are difficult.