By Josh Perry, Editor [email protected]
A collaborative effort between NASA, the U.S. Department of Energy National Renewable Energy Laboratory (NREL), University College London (UCL), the U.K. National Physical Laboratory Diamond Light Source (DLS) and the European Synchrotron Radiation Facility (ESRF) has developed a device that allows researchers to study a short between electrically-conducting layers to better understand the process of thermal runaway in lithium-ion batteries.
By using controlled explosions, scientists gain a better understanding of how thermal runaway occurs. (Wikimedia Commons)
According to a report from Technology Networks, the research team built a device that creates internal short circuits (ISC), mimicking those that take place in common lithium-ion cells and lead to catastrophic failures in batteries.
“The ISC device is a metallic ‘puck’ encased in low melting point wax between electrodes, making it possible to activate an ISC on-demand and at a pre-determined location within the cell, to recreate ‘worst-case’ failure scenarios,” the article explained.
Advanced imaging techniques allow the researchers to witness the short circuit at 1,000 images per second because cell rupture can occur in only 0.01 seconds. Using the ESRF and the DLS high-speed synchrotron X-ray computed tomography (CT) and radiography along with thermal imaging, the scientists could track how the rupture evolved into a full thermal runaway.
“At DLS, researchers are able to make use of beamlines (experimental stations) optimized with different capabilities,” the article continued. “Using the high-speed radiographic imaging capability of the I12 beamline allowed them to image the nucleation of failure within a working battery, and see at very high speed how that failure can propagate through an individual cell and from one cell to another. They were able to see the exact mechanism by which failure starts and how it spreads, and to design systems to prevent the spread of that failure.”
The synchrotron allowed the scientists to see the full details of the build up to rupture and to characterize four types of failure: controlled ejection of contents, cell bursting, puncture of the top button, and escape of the internal mandrel. They also were able to show that a second vent at the base of the cell could prevent bursting by releasing gas buildup.
“Being able to investigate battery cells at different length-scales, from the atom to the system, provides a wealth of information that will inform the design of the next generation of lithium ion battery cells,” the article concluded.
Read more at https://www.technologynetworks.com/analysis/articles/on-demand-explosions-are-helping-to-build-better-batteries-308350.
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