Analog front ends that balance cells and eliminate mismatches of cells in series or parallel combination significantly improve battery efficiency and increase the overall pack capacity.

A battery is a collection of two or more cells, but in popular usage battery often refers to a single electrical cell.

Battery size generally refers to the shape, voltage, and terminal layout of a battery. Thus the term "size" has become interchangeable with "type". Batteries of different types will usually not have the same dimensions and terminal layout.