No, it’s a cell 🇺🇸

[ElleneAsanto]

Just to balance the occasional Yank bashing, I’m reminding my fellow Brits that you do not buy a package of AA “batteries”.

An individual unit of power storage is a cell. As we all know from GCSE Physics.

When multiple cells are lined up they form a battery of cells.

Just as multiple artillery guns facing the same way are a battery. Or keeping chickens in rows of cages is battery farming.

I presume the usage has arisen because a car battery looks as if it is a single unit, although it also contains multiple cells.

Correct through usage. It means what we collectively choose it to mean.

Take it up with Duracell

https://www.duracelldirect.co.uk/m/multi-purpose/standard-batteries.html

There's classroom science and everyday science.
In the classroom you measure mass in Kg and call batteries cells.
In the real world you jump on the scales to weigh yourself in Kg and put batteries into a torch.
It's incorrect but there you go.

See also inertia which in common parlance is used purely for not wanting to move rather than also wanting to continue to move.

Near where I live, there is an old disused railway embankment known locally as "the battery". This is a common usage in my part of the country because many of the engineers who worked on railway embankments had former experience of building earthworks for batteries of artillery to stand on. By extension, the earthworks themselves became known as batteries, even in the civilian, railway context.

The point being, of course, that usage evolves.

Do Americans call each battery a cell? Is that why mobile phones are called cell phones in America?