Exploding-battery epidemic caused by 'lithium moss'
iPod trouser inferno horror a thing of the past?
Researchers at Cambridge University have proposed using nuclear magnetic resonance to work out why lithium batteries keep exploding.
Lithium batteries are great - lots of battery life and relatively fast charge time: so it seems churlish to avoid using them just 'cos they blow up every now and then. But now researchers are hopeful that a new way of looking at the problem will yield methods to prevent even that minor drawback.
The problem is in the dendrites - tiny fibres of lithium that form on the carbon anode when you charge a lithium battery. Charge it too fast, and too often, and the dendrites get long enough to short out the battery - cue explosion.
The details of how dendrites form are opaque; they're more usually associated with the freezing process and it's hard to look into a charging battery using optical or scanning electron microscopes, which is why NMR is now being proposed.
The paper describing the process, which appears in the Nature Materials, calls for a very small lithium-ion battery - about 1cm long - which can be watched in minute detail by an NMR scanner to monitor how the dendrites (or Li-moss as the researchers term it) grows.
The idea is that once the process is observed in real time scientists will be able to play around with the conditions to find out why it happens and, ideally, prevent it. That's going to be really important if we're going to be driving around in lithium-ion-powered cars, or riding lithium-powered motorcycles - though what happens when they hit each other is another question entirely. ®
Kate moss is a subset of Si Moss, more known for exploding on aircraft and in niche adult entertainment.
I recall when lithium batteries going pop first made the news and the media called upon lots of spurts to be suprised and claimed they hadn't seen it coming. Funny that, because I recall when people first started using lithium cells in RC aircraft (very useful in that environment - fast charge time and lots of charge for their weight) and there were quite a few explosions reported. This was way before exploding iPods made the news, so presumably these tech experts the media were quoting had a very limited field of expertise. Or perhaps they worked for the battery companies and admitting that they knew lithium cells had a habit of combusting could have been a bad marketing move.
Ed, modern scanners don't revolve the subject, they revolve the detector.
That's what the grinding noise is that comes out of the MRI scanner when you lie inside wondering if the damned thing is about to explode and whether some nitwit will enter the room with an oxygen cylinder and burst your head like a ripe melon before this interminable test is over and LET ME OUT OF THIS BLOODY MACHINE!
Because I once studied with one of the pioneers of NMR at UEA (home of Climategate), I was able to talk my way into the control room once my scan was over and I watched the pictures being built.
It was hands-down the neatest moment I've ever had out of that Chemistry degree.
Whooda thunk messing around with spinning tubes and plotters with the wrong pen so the bloody thing kept drilling holes in the paper while the never-ending set-up was being done using an orange (!) crt oscilloscope to set the phase and who forgot to jam the elevator doors and now we'll have to start again and the damned sample is spinning too fast now NO DON"T TURN THE MAGNET OFF AARRGGH would actually become the really neat and useful technology it has?
Now if only we can bring the price of using it down out of the ionosphere...