The Sweep Energy Storage System is a result of two company's discussions in order to establish better battery re-use technologies starting back in 2018. It is located at Yokkaichi Thermal Power Station, Nagoya and it is owned by JERA--a 50:50 joint venture between utilities Tokyo Electric Power Company and Chubu Electric Power.
The system was built using batteries from hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), battery electric vehicles (BEVs) and hydrogen fuel cell vehicles (FCEVs). Toyota uses nickel-metal hydride batteries for some of its hybrid vehicles.
Toyota's new storage system is equipped with a function called sweep, which allows the use of reclaimed vehicle batteries, which have significant differences in performance and capacity, to their full capacity regardless of their level of deterioration. The sweep function, developed by Toyota Central R&D Labs, Inc., is a device that can "freely control energy discharge by switching electricity flow on and off (bypassing) through series-connected batteries in microseconds".
The sweep function also enables direct AC output from the batteries, while reusing onboard inverters eliminate the need for a power conditioner (PCS). That contributes to reducing costs and helps avoid power loss when converting from AC to DC by PCS, with the aim of improving effective energy use.
The project plans to operate grid storage batteries for recharge and discharge operations, connected to the Chubu Electric Power Grid Co., Inc. power distribution system from a facility at JERA's Yokkaichi Thermal Power Station. JERA and Toyota aim to introduce approximately 100,000 kWh of supplied electricity in the mid-2020s, thereby not only reducing the overall cost of the energy storage system, but also contributing to reduction of CO2 emissions.
Source: Toyota