a 'dead battery' = ('Brit') a 'flat battery' [=a battery that has no more electricity]
The operation was performed by a 'battery' of doctors.
He was found guilty of 'battery'.
(..) been dependent on machines to survive. Fate, it seems, is not without a sense of irony. The human body generates more bioelectricity than a -voIt battery. And over BTUs of body heat. Combined with a form of fusion ... ... the machines had found all the energy they would ever need. We are grown. (..)1999 The Matrix