October 28, 2022: Japan’s Toyota group and domestic power utility giant JERA have commissioned a second-life battery storage system comprising lithium ion, nickel metal-hydride and lead acid chemistries, the companies announced on October 27.
The BESS has a so-called ‘sweep’ function, developed by Toyota’s Central R&D Labs unit, which the firms say allows the use of reclaimed vehicle batteries with significant differences in performance and capacity to their full capacity, “regardless of their level of deterioration”.
This is a major step forward in creating a BESS by re-using second life batteries where typically these are of a similar level of degradation (and often similar previous usage patterns). This makes the related software and architecture simpler to design.
The partners say the 485kW/1,260kWh ‘Sweep’ BESS was built using batteries reclaimed from a range of electric vehicles and is in operation at the Yokkaichi power plant in Nagoya.
Sweep will use grid storage batteries for “recharge and discharge operations” while connected to the Chubu Electric Power Grid company’s power distribution system, the partners said.
The companies claim the sweep function can freely control energy discharge by switching electricity flow on and off through series-connected batteries in microseconds.
In addition, the sweep function enables direct AC output from the batteries, while reusing onboard inverters eliminate the need for a power conditioner (PCS), which the partners said helps reduce costs and avoid power loss when converting from AC to DC by PCS.
JERA and Toyota said the project has its origins in talks the company started in 2018 to consider battery re-use possibilities, in the face of growing demand for energy storage to support an expansion of renewables to tackle climate change.
“Limited supplies of battery materials including cobalt and lithium mean there is an ongoing need for environmentally conscious initiatives, such as reclaiming used electrified vehicle batteries for effective use as storage batteries,” the companies said in a statement.