Rod this may be, [and looks like], a steam explosion. The current passing through the electrolyte forms superheated water. Temperature and pressure build in the sealed case till it splits, instantly forming about 2000 volumes of steam for 1 volume of water contained in the electolyte gel. Very thin seamless welded steel cans will sustain massive pressures - and that Duracell brand is a Rolls Royce of batteries in Europe. We can see that the end caps fail first, though the seam is coming apart. The chemicals in the cell are not intrinsically explosive, but sal ammoniac is aggressive and can damage your eyes. Steam is nasty stuff with over 1000 btus per lb latent heat and it produces horrific burns/scalds. Schrapnel is another hazard. You may get some explosive gasses too.
I worked in Gummint ammo factory for 30 years. Messing with stuff like this can eventually lead to the old 'familiarity breeds contempt syndrome' and then to getting hurt. I once took over, with another 'new boy' Engineer, an old office previously occupied by a sufferer from just this affliction. How I laughed like a drain when he found
his old desk drawer to be stuffed full of detonators, all neatly wrapped up in a set of his divorce papers! - 'Till I found that the old leather Gladstone Bag under
my desk, and upon which my size 11 boots had been beating a happy tattoo, contained about 10 pounds of TNT flake in an unmentionable state of decomposition! Boy, you should have seen us two idiots, jammed in that office doorway doing the
Fred Flintstone Shuffle! Funnily enough, we we both laughing like drains!
Something psychological in that, do you think?
Take care with the experiments, and make sure you educate that boy in Safety Fun!
Alan
