Toyota Motor Corporation and Mazda Motor Corporation announced that they have started joint field tests of Toyota's “Sweep” Energy Storage System (ESS) at Mazda's headquarters plant in Hiroshima, Japan. The tests are designed to help develop an electric vehicle (EV) battery ecosystem, contributing to carbon neutrality.

The tests involve using both Mazda’s in-house power generation system at its headquarters, which is claimed to be the only power generation system operated by an automaker in Japan, and Toyota's Sweep system which uses EV batteries, with the two systems connected through their respective energy management systems (EMS).

Toyota said its Sweep system works by “rapidly switching each battery's power flow on and off, even when new batteries are connected to degraded batteries or batteries of different capacities.”

The tests are designed to verify the stability, quality, and efficiency of the charging and discharging of ESS. In the future, the two automakers plan to use ESS to regulate power supply and demand from renewable energy providers, which fluctuates significantly depending on weather and time of day.

Toyota stated that “building a battery ecosystem is part of the seven mobility industry issues that the Japan Automobile Manufacturers Association is addressing. In support of stable procurement of critical resources and the building of a resilient supply chain, the battery ecosystem aims to sustainably reuse batteries in Japan, including electrified vehicle batteries.”

Toyota confirmed that “going forward, both companies will continue to take on challenges across the industry, focusing on a multi-pathway approach to achieve carbon neutrality and strengthen industry competitiveness.”