Mrs niu had been complaining for several days that her phone battery was not behaving – her phone would go from an apparently full charge to nothing in very short time. Don’t make so many calls was my first thought but the battery usage chart seemed very odd – the charge appeared to drop off a cliff periodically. She carried on trying to charge up but the performance became increasingly erratic. Time for a new battery I thought.
After a lengthy search across town she had her new battery and as we sat waiting for dinner, I offered to install it for her. Upon pulling out the old battery we immediately saw it was swollen to around double its original thickness – quite an alarming sight. Mrs niu quietly wrapped it in a napkin to avoid it distracting me during dinner.
But of course it did distract me. First the thought of dendrites growing and how close had it come to a fiery end whilst on the charger. Then the thought of what to do with this swollen cell... Can’t put it in the rubbish – there are enough warning labels on the battery to dissuade a sensible person from doing that. The thought of a rubbish truck compacting the battery and spontaneously igniting its load was becoming all too vivid. But there are no recycle options yet. What to do? What to do?
As the empty beer bottles accumulated before me a plan was quietly emerging. This battery was dangerous and it had to be disarmed before it could be safely disposed. The beer was dismantling the common sense inhibitions that a perfectly respectable chemical engineering degree had instilled in me.
So back at home, and certain that I knew what I was doing, I found a suitable garden implement to do the deed. With a bucket of water (just in case) and full PPE (I donned my reading glasses for a better look) I felt as ready as I was ever going to be. So it was on to the “folks, don’t try this at home” moment. First blow with the spade – nothing. Second blow – nothing. I was giving up hope but not losing interest when the fifth blow of the spade got a reaction.
The explosion was an order of magnitude more violent than I had expected. Oh yes. I let out a profanity – not a mild one. The neighbour's children stopped bouncing on their trampoline and shouted "Woah… is it all legal over there…?" Children – got to love them…
The explosion ejected bits of separator membrane over a 3m radius – quite impressive considering the low trajectory and poor aerodynamic characteristics of the membrane. Meanwhile the bulk of the battery proceeded to burn with a small but intense flame, scorching a 300mm diameter burn mark in my recently sown front lawn. And then as, I admired my handiwork, I remembered the water. So, with the battery quenched and definitely disarmed, I figured it was “job done”.
But now I sit here reflecting on this with very mixed feelings. On the one hand, I am somewhat stunned at the energy contained within a tiny 8.09 Wh battery – the energy intensity is nothing less than impressive.
On the other hand, I see all too clearly that safety remains the Achilles heel of the current Li-ion battery technology – the sooner we see safer solid state Li batteries, the better. They are coming but they cannot come soon enough.
And, of course, at some point, there will need to be a recycling industry, although, with demand ramping up so quickly, it will be many years before it can take a meaningful share of supply.
I’ll resign myself to the thought that it is still early days – better technology surely lies ahead. It is needed.
In case anyone is feeling inspired, I don’t recommend to DYOR on this one…
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