One-second check could boost second-life EV battery use

UK researchers have developed an almost instant battery test that could help divert millions of EV batteries from recycling or scrappage.

The team from the Electrochemical Innovation Lab at University College London (UCL) and the Department of Engineering Science at the University of Oxford, have developed a diagnostic method that can check the health of a battery module in just one second.

Previously, such tests could take anything from minutes to hours to assess the health of a single cell, meaning testing an entire module could take days.

The researchers say their new technology could help ensure more batteries are put into ‘second-life’ use rather than discarded or stripped down and recycled.

While EV batteries have a finite usable life powering a car, a huge number are still fit for less intensive usage such as home or commercial energy storage. However, until now it has been slow and expensive to determine whether an “end of life” EV battery is suitable for such repurposing.

The researchers say their new method – known as multi-channel, multi-frequency electrical excitation response (MMER) – is hundreds of times faster, non-invasive, and can be scaled up to test entire battery packs. It can also perform real-time checks while batteries are being charged or discharged.

Professor Paul Shearing, director of the Oxford Martin School Programme on Circular Battery Economies, commented: “One of the biggest barriers to reusing EV batteries is knowing, quickly and accurately, which ones are still good enough.

“This breakthrough means we can check the health of a whole module in seconds. That makes large-scale reuse viable and will help batteries last longer, perform better and create less waste.”

Co-team leader Dr Shangwei Zhou said the system could also have implications for vehicle control systems. He noted: “The very fast nature of this diagnostic technique allows us to study the batteries while they are actually operating, charging and discharging, which has not been possible before. This could unlock advanced ‘live’ understanding that could be used in the on-board control systems of electric vehicles”

Recent research suggests that in most cases EV batteries will still be usable after the rest of the car has reached the end of its life. According to the UCL and Oxford researchers, by 2035 around 150,000 tonnes of EV batteries in the UK are expected to reach the end of their on-road life each year. They warn that without more thought around second-life use this could see millions of pounds’ worth of rare resources discarded unnecessarily.

They added that the technology had implications far beyond the UK and could help bring more affordable renewable energy and storage to regions in sub-Saharan Africa and South Asia which still lack electricity supplies.