Batteries are an increasing part of our transition to a low carbon economy, but we continue to struggle to know with confidence the health of a battery. A new collaboration between Lancaster University’s Physics Department and the University of Waikato in New Zealand has been working on providing insights into a battery’s health, allowing users to track changes in its performance whilst the battery is in normal operation.

The Lancaster researchers includes Physics PhD student Juliane Bjerkan and Professor Aneta Stefanovska, both of the Nonlinear and Biomedical Physics research group. To calculate the relative “age” of a battery, and its performance, the pair have been conducting analyses of the patterns and relationship between voltage and current and assessing how these change over time.

The team has been utilising methods reported in a recent paper that rely on measuring oscillation phases - repetitive fluctuations in time with wave-like peaks and troughs – in order to construct an overview of a battery’s health. By using an approach known as “wavelet phase coherence”, developed by the Nonlinear and Biomedical Physics group at Lancaster, the team were able to measure and compare changes in the oscillation phases of both current and voltage and identify any phase coordination (or orchestration) between the two by highlighting consistencies between the different signals’ waveforms. Changes in this coordination could indicate a forthcoming failure in the battery, potentially months before the battery actually reaches the end of its life.

This method heralds a new era in the tracking of battery health. Unlike other methods for tracking the remaining lifespan of batteries, phase coherence analysis allows users to not only measure the battery’s performance whilst it is still in use but also allows them to detect an issue with the battery before there is any notable change in its performance. This development has potentially huge ramifications for a number of industries, including medical and transportation, as sudden failures in batteries used in either application can have serious, and potentially life-threatening consequences.

On the findings of the paper, PhD student Juliane Bjerkan commented: “It was great to see methods I have used to study biological oscillations also provide insight into battery health. It really showed how versatile the methods are.”

Professor Aneta Stefanovska said: “It was wonderful to work with Marcus when he was in Lancaster and wonderful to see that our methods, especially phase coherence, were able to detect battery failure. Collaborating with international partners can bring strength to research and varying perspectives, as well as new challenging problems to tackle with our methods and approaches.”

Speaking of his visit to the University, Dr Marcus Wilson from Te Aka Mātuatua School of Science, University of Waikato reflected: "Spending time at Lancaster University has been highly valuable. Together we've been able to combine our different expertise to achieve an outcome that could not have been done as individuals. "

Professor Jonathan Scott from Te Kura Mata-Ao School of Engineering, University of Waikato focused on the practical applications of their research collaboration: "Imagine knowing how worn out an Electric Vehicle you consider buying is; imagine having your medical implant last years longer; imagine having months of warning before your phone battery dies; imagine being able to find out what loaning your Electric Vehicle to your son or daughter does to age its battery!"