Revolutionary method reveals impact of short circuits on battery safety

How lithium-ion (Li-ion) batteries behave under short-circuit conditions can now be examined using a new approach developed by a UCL-led team to help improve reliability and safety. The use of high energy density Li-ion batteries is ubiquitous - from powering portable electronics to providing grid-scale storage - but defects can lead to overheating and explosions. Although catastrophic failure is extremely rare, recent high-profile cases including the recall of Samsung's Galaxy Note 7 smartphone line and the grounding of an aircraft fleet highlight why it's important to understand battery failure.    'In previous work, we've tracked Li-ion battery failure caused by extreme heat in 3D and real-time, but this is the first time we've tracked what happens to the temperature and structure of cells when we short circuit the battery in a controlled way at an internal location of our choosing, initiating a series of potentially dangerous events,' explained first author, Dr Donal Finegan (UCL, NASA and NREL). 'This is of particular interest, as short-circuiting is thought to be responsible for a number of high-profile, real world failures. Knowing when and where the cell will fail has allowed us to characterise what happens during catastrophic failure in-depth using high-speed X-ray imaging. This provides us with new insights to help guide the design and development of safer and more reliable Li-ion batteries.' The study published today in Energy and Environmental Science involved researchers from UCL, NASA-Johnson Space Center (USA), the U.S. Department of Energy's National Renewable Energy Laboratory (NREL, USA), WMG at the University of Warwick, Diamond Light Source (UK), The European Synchrotron (ESRF, France) and the National Physical Laboratory (NPL, UK).