Patent attributes
A battery unit including a battery, a circuit board, a switching device which achieves charge or discharge of the battery, and a casing made up of a bottom and a peripheral wall. The battery is disposed on the bottom. The circuit board is arranged farther away from the bottom than from the battery. The switching device is located closer to the bottom than the circuit board is. The switching device has a visible area visually or optically perceived, as inwardly facing inside the casing from outside the circuit board, and includes a data-retaining area on which data on characteristics of the switching device is provided, for example, in the form of a code. This structure facilitates the ease with which the data on the characteristics of the switching device is visually or optically read out of the data-retaining area without having to have an increased size of the battery unit.
