We all know that lithium-ion batteries can fail catastrophically. But other batteries can also burst into flames unprovoked, and a team of researchers is using real-time 3D imaging to understand exactly how. A team of engineers form University College London has been using X-ray imaging techniques to captures 3D views of what happens inside disposable lithium batteries. You might wonder why they're bothering, but the study was initiated following a fire aboard a Boeing 787 Dreamliner at Heathrow Airport in 2013, which was found to be caused by a disposable lithium battery in the aircraft's emergency locator transmitter.
Usually, those kinds of batteries are installed and forgotten about, allowing the systems to work indefinitely because of their relatively low power use. But the images acquired by the researchers, shown above, show that what happens inside is worth worrying about a little more.
"On the outside, the batteries look like they are doing their job normally, explains Donal Finegan, one of the researchers, in a press release. "But inside we saw the structure was undergoing great change. Electrical activity was high in some areas of the cell, whereas it was low in others; layers of electrode material separated and cracked. All of these changes in structure affect the flow of electricity and reduce the performance of the cell."
You can see that damage clearly in the images above, published in Advanced Science, where long cracks form, emanating from the tips of the electrodes. The researchers reckon that the technique should be used to measure the performance of batteries before they're used in safety-critical situations — like, uh, aeroplanes.