Battery
Batteries are mainly composed of a reservoir filled with electrolyte, into which two electrodes with terminals for connecting to an external circuit are immersed. In many cases, the reservoir may be divided into several parts, each compartment (element) being a battery by itself; these elements are usually connected in series to provide higher voltage. Several such connected elements are referred to as a battery. Also, several batteries can be combined within a larger casing. Batteries may consist of either wet or dry cells.
Source: "Explanations to the Harmonized Commodity Description and Coding System for Foreign Economic Activity of the Russian Federation (HSN of Russia)" (prepared by the Federal Customs Service of Russia) (volume 4, sections XVI - XXI, groups 85 - 97)