storage cell
secondary cell

He cannot have an electric motor, for the storage cells would weigh too much.

"There is, in fact, no power at all; we are merely bleeding the storage cells."

I believe it is a fault in the storage cells.

Could a mage have left a storage cell somewhere on the grounds?

Also what about other things that use storage cells?

Occasionally, there are bursts of power that destroy the storage cells.

Some of the systems still had power in their storage cells.

From the board back to the reserve-power storage cells, deep in the mountain.

This storage cell has two stable states which are used to denote 0 and 1.

There is power in some kind of storage cell, but it's very low level.