A cell is the basic device comprising two electrodes separated by an electrolyte. The name of the cell usually includes reference to the materials used in the construction and the voltage of each cell depends on the chemicals used, eg an Alkaline Manganese AA 1.5 V, or a Lead-acid cell of about 2 V.

A battery is a collection of cells eg the PP3 9V (6 cells in series) or the Lead-acid car battery (typically 12 V, also 6 cells). Although the voltages are quoted usually as if they were accurate, mostly they are not. Voltages vary according to many factors eg temperature and state of charge.