Used Nissan EV batteries given second life in Japan’s railways

Batteries from Nissan LEAF electric vehicles (EVs) are being repurposed for use at railway crossings in eastern Japan.

The trial with East Japan Railway Company, one of the company’s leading rail providers, is testing the use of the used batteries as an alternative to lead-acid batteries in emergency power supply units.

The emergency power supply units are installed at each railway crossing to ensure they operate properly and maintain safety at all times, including during scheduled maintenance work and temporary power outages.

The trial began in January 2021 at the Atago crossing on the Jōban line in Fukushima Prefecture and is ongoing, with the autumn a key time to test the resilience of the batteries to lightning surges.

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If lightning strikes a vehicle, the electricity flows to the ground through the vehicle’s body without impacting the battery.

At a railway crossing, the battery is susceptible to voltage surges from its connections to devices such as barriers, alarms and control equipment. To withstand these, modifications have been made to the battery control infrastructure.

At the end of useful EV life a Nissan LEAF’s lithium-ion battery retains up to 80% of its electricity storage capacity, which can then be directed elsewhere. In addition to adding value to the battery, repurposing, which is carried out by Nissan’s partner 4R Energy Corporation, reduces the CO2 emissions and rare resource usage that would come with the manufacture of a new battery.

Second life benefits

Kaito Tochihara, assistant chief researcher at the East Japan Railway R&D centre, says the findings show that switching from lead-acid to repurposed EV Li-ion batteries not only promotes sustainability but also leads to improved performance from the battery itself.

Compared to lead-acid batteries, the reused Li-ion variety requires only one-third of the charging time. They also are more durable, lasting on average 10 years, compared to the 3-7 years for a standard battery.

Maintenance is another issue. The lead-acid batteries require periodic visits to check the state of charge and any deterioration. However, with the repurposed Li-ion batteries, the attached control system enables remote checking of the battery’s status.

In addition to the Atago railway crossing, there are plans to test the batteries at other crossings on the Jōban and Mito lines to analyse the effect of lightning surges and other environmental factors across a wide range of areas.

“We will continue to analyse battery performance, building on promising initial results. We will also use feedback from those who maintain the railroad crossings, making them safer to use,” says Tochihara.

He adds that railways powered by electricity come in various sizes.

“If we can confirm in this trial that repurposed batteries are safe for use on railways, then I think we can expect this initiative to be expanded, for example, in wireless communications equipment.”

As the use of EVs grows, the availability of reusable batteries also will increase opening the way for other novel second life storage use cases.