An international team led by researchers at UCL has revealed new insights into the workings of a lithium battery by virtually “unrolling” its coil of electrode layers using an algorithm designed for papyrus scrolls.
In a study published in Nature Communications, “4D imaging of Li-batteries using operando neutron and X-ray computed tomography in combination with a virtual unrolling technique,” researchers combined X-ray and neutron tomography to track the processes deep within a lithium battery during discharge. They then used a mathematical model designed for ancient manuscripts too sensitive to be physically opened to “unroll” the electrode layers, so aiding analysis and revealing that different sections of the battery were operating differently.
Researchers found that using the two complementary imaging techniques and “unrolling” the electrodes while they are in normal use provides a fuller and more accurate understanding of how the battery works and how, where and why it degrades over time. Unseen trends in the spatial distribution of performance in the cells were observed.
The method paves the way for developing strategies for improving the design of cylindrical cells using a range of battery chemistries, including by informing better mathematical models of battery performance. As such the method may facilitate improvements in the range and lifetime of electric vehicles of the future.
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Image: Reconstructed tomograms from neutron and X-ray computed tomography. Clearly visible in the X-ray images is the nickel current collecting mesh, which appears brighter than the active electrode material. CREDIT: UCL/HZB/ILL