The prototype equipped with a 5kWh Li-ion secondary battery
The prototype equipped with a 5kWh Li-ion secondary battery
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Toyota Motor Corp and Toyota Housing Corp announced April 14, 2009, that they began in earnest the development of a Home Energy Management System (HEMS) equipped with a power storage function.

The companies plan to commercialize the system in 2011, starting with trial sales by Toyota Housing. The system will be priced at several hundred thousand yen (several thousand dollars) when they hit the market, the companies said.

Existing HEMSs are equipped with functions to display energy usage and control home appliances such as air conditioners and lights. In addition to these functions, the system to be developed by Toyota Motors and Toyota Housing will feature a function to store electricity.

Inexpensive nighttime power and excess power generated by residential photovoltaic equipment in the daytime can be stored in a storage battery such as a Li-ion secondary battery to cope with power shortage in the daytime.

The new system is composed of the main body, which consists of a storage battery, an electric power converter and a controller, and a display/control panel for use inside a house. Toyota Motor will lead the development, and Toyota Housing will manage product planning. Denso Corp and Misawa Homes Co Ltd will help develop the main body and the display, respectively, of the system.

Toyota Motor has already completed an initial prototype that incorporates a Li-ion secondary battery with a storage capacity of 5kWh. The storage battery used in the system to be commercialized will be determined by conducting evaluations based on assumed residential electric load, etc.

Furthermore, Toyota intends to realize collaborations of the HEMS with a plug-in hybrid electric vehicle (PHEV) and an electric vehicle (EV), which are expected to be widely used, in the future.