Non-destructive battery testing — New method developed with GSI participation
Rechargeable batteries are everywhere — from portable electronic devices and electric vehicles to renewable energy storage. Battery failures are often due to the loss or chemical degradation of the electrolyte. An international research team involving the Helmholtz Institute Mainz, a branch of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt, Johannes Gutenberg University Mainz, Physikalisch-Technische Bundesanstalt in Berlin, and New York University has now addressed the question of how to enable nondestructive diagnosis of the electrolyte through the battery casing using special nuclear magnetic resonance techniques. The results have been published in Chemical Science.
How does a rechargeable battery work? A battery stores electrical energy in chemical form. Inside are two metal electrodes and a medium called electrolyte. During discharge, chemical reactions take place in which charged particles migrate inside, while electrons flow through the external circuit, supplying electrical energy. In a rechargeable battery, this process can be reversed: charging resets the chemical processes so that the energy storage device can be used again. Over many charging cycles, the electrolyte changes, ages, or can leak, which can lead to the battery becoming unusable or, in the worst case, even pose a hazard due to heat generation or explosion.
“Reliable methods for nondestructive testing of the battery condition are currently lacking, as the quantity and chemical composition of the electrolyte cannot be determined through the housing using conventional techniques. This is exactly where our research comes in,” says co-first author Dr. Anne Fabricant, who was involved in the experiments at both the Helmholtz Institute Mainz (HIM) and the Physikalisch-Technische Bundesanstalt in Berlin. “We examine the batteries using what is known as zero-to-ultra-low-field magnetic resonance. The casings are transparent for this technique, allowing us to see inside.” In this diagnostic technique, also known as ZULF NMR, nuclear magnetic resonance is measured without the influence of a strong external magnetic field.
“In our tests, we were able to demonstrate the direct detection and quantification of both the solvent and the lithium salt components of commercial electrolytes through metal battery casings,” explains Professor Dmitry Budker, who works at HIM and Johannes Gutenberg University Mainz and is one of the champions of the ZULF NMR method. “These were realistically packaged battery cells, including so-called pouch-cell geometries used in electric vehicles. We have thus proven the concept and paved the way for a practical application of the technology.”
In the future, ZULF NMR could be used to test the integrity of rechargeable batteries during operation as part of operando measurements. A topic of increasing importance, as these batteries have many usages, for example in small mobile devices such as cell phones and notebooks, but also on a large scale in electric vehicles. They are particularly relevant for the storage of renewable energies. In addition, the measurements provide a deeper understanding of electrochemical processes and the development of next-generation battery cell technologies.
“The ability to nondestructively characterize electrolyte volume and composition supports superior battery design and serves as a vital quality control tool throughout a cell’s lifecycle,” says key project collaborator Professor Alexej Jerschow from New York University, who is a Carl-Zeiss-Humboldt Research Award recipient.
Professor Budker's research team is planning further experiments to improve diagnostics. “We have many ideas on how we can make detection more accurate and faster, how we can examine larger batteries, and how the process can be made more cost-efficient,” says Budker. “I am convinced that in the long term, this technology will find its place alongside other, more invasive diagnostic methods.”
Originalpublikation:
https://doi.org/10.1039/D5SC04419G
Weitere Informationen:
https://www.gsi.de/en/start/news/details/2026/03/05/zulf-nmr-battery-testing
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