Toshiba Corp. has unveiled the idea of a "Charge Grid," charge-discharge equipment system that uses rechargeable batteries installed in various areas.
With the Charge Grid system, surplus electricity generated by photovoltaic (PV) cells is stored in rechargeable batteries and can be used, for example, in EV rapid chargers. The batteries are placed in various areas to promote the use of electric vehicles (EVs) and photovoltaic power generation.
The Charge Grid system consists of bidirectional inverters, lithium-ion (Li-ion) rechargeable batteries and rapid chargers. The electricity grid and the Li-ion batteries are connected via the bidirectional inverters. And the rapid chargers are connected to the lines that connect the batteries and the inverters.
Surplus electricity generated by PV systems installed in, for example, residential buildings is used to charge the Li-ion batteries. And, during nighttime hours, when electricity rates are low, they are charged by using electricity from the grid. Then, the charged electricity is used to rapidly charge EVs and in case of power outage.
The Charge Grid system eliminates the need for construction work for high-voltage electrical substation equipment, reducing the cost for installing rapid chargers (though there is a cost for installing Li-ion rechargeable batteries).
Also, the system helps make efficient use of the surplus electricity of PV systems. When surplus electricity is supplied to a power grid, the voltage of the grid electricity increases.
Therefore, it is not currently possible to provide the surplus electricity to the grid when the voltage of the grid electricity reaches a certain level. On the other hand, the new system enables to store the surplus electricity of PV systems, which has been discarded thus far, in rechargeable batteries.
Toshiba plans to commercialize the Charge Grid system in a few years. It will sell the system and provide services using the system.
