バッテリーは定義上、セルの集合体です。セルは化学物質の小さな缶です。そして挑戦は非常に高エネルギーのセルを大量に取り、安全に大きなバッテリーにまとめることです。

A battery by definition is a collection of cells. So the cell is a little can of chemicals. And the challenge is taking a very high-energy cell, and a large number of them, and combining them safely into a large battery.