In American English it is all batteries:  car battery, camera battery, flashlight battery, laptop battery, backup battery, bus battery.  In the old days there was the word "pile" or rather, "electric pile", (like pilha in Portuguese), but it has not been in much usage for 100+ years.  The word "accumulator" is rarely used for battery, but it is used to refer to a component of the addition module in the innards of a computer chip.

Incidentally, the word "piles" is also an old word for hemorrhoids!

Go figure...

CRS