Few days back, I had this incident of exploding Duracell battery at my home.
Battery installed = 12th August 2006 (I religiously write the installation date on batteries, tube light, CFLs etc).
Battery expiry date = Mar 2010.
Exploded on = 25th July 2012.
Though the battery expired on Mar 2010, I never bothered to look at it (or change it), because, the equipment which was using this battery was running perfect. Once I notice that the battery is dying, I removed it from the equipment. Please note that the explosion happened when the battery was not supplying any power and was waiting to be thrown.
From picture 1 and 2, you can guess the intensity of explosion; the back plastic was thrown away, internal matters were all spilled out with 3 loud pop.
Hence, I suggest that we should not use Duracell batteries beyond the expiry date to avoid such incidents repeating again.