Freezing in liquid nitrogen has potential to save ‘thousands of pounds’
Researchers at the University of Warwick have developed a new solution for the previously expensive process of transporting damaged car batteries. The researchers in collaboration with Jaguar Land Rover engineers have been proposed a way to freeze the lithium ion batteries with liquid nitrogen at -35 deg C. The current regulations require that batteries are put in an explosion-proof container, to avoid the risk of - a process that can cost £20,000 a time.
However, the cryogenic process allows the batteries to be transported in plastic containers which cost only a couple of hundred pounds.
Explosion boxes are used to contain the battery in case it goes into thermal runway, an overheating condition which can lead to violent explosions and toxic gases being released, the researchers said. However being able to cryogenically flash freeze the batteries completely removes the risk of an explosion, and could therefore mean they can be transported safely in a plastic box.
The researchers at the Warwick Manufacturing Group published the results in a paper, ‘Cycle life of lithium ion batteries after flash cryogenic freezing’ in the Journal of Energy Storage. In the paper, they also demonstrate that cryogenic freezing does not reduce lithium ion battery’s energy capacity or affect cycle or service life, and could be transported in a safer way.
The researchers who were part of the ELEVATE project funded by ESPRC, Catapult and supported by Jaguar Land Rover tested the batteries activity before they froze cells with liquid nitrogen and after.
When being transported batteries will have to be kept in a truck at -35 deg C, the WMG said. However the amount of packaging is significantly less than explosion proof boxes, making the process more sustainable.
Dr Thomas Grandjean from WMG, at the University of Warwick said: “Transporting damaged and defective batteries is an expensive and unsustainable process, however being able to freeze them with liquid nitrogen could save thousands of pounds and help electric vehicle manufacturers be more sustainable. We tested the batteries in the most extreme abuse conditions, such as driving nails through the cells and inducing external short circuits, proving that the freezing process is effective and safe.”