麻豆传媒

Last night, my wife and I were awoken by two loud cracks a second or so apart. The day after, I discovered that the 9-volt battery cell I鈥檇 removed from a fire alarm the night before appeared to have exploded (see photo). What might have caused this in a depleted cell, and why two cracks?

David Cross, Malvern, Worcestershire, UK

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