DEFINITIONS

DEFINITIONS DOE-HDBK-1084-95 Lead-Acid Storage Batteries Batteries Page 2 Rev. 0 DEFINITIONS Active material - Constituents of a cell that participate in the electrochemical charge/discharge reaction. Battery - Two or more cells electrically connected to form a unit. Under common usage, the term "battery" also applies to a single cell. Capacity - Number of ampere-hours (Ah) a fully charged cell or battery can deliver under specified conditions of discharge. Cell - Basic electrochemical unit used to store electrical energy. Current - Flow of electrons equal to one coulomb of charge per second, usually expressed in amperes (A). Cutoff voltage - Cell or battery voltage at which the discharge is terminated. The cutoff voltage is specified by the manufacturer and is a function of discharge rate and temperature. Cycle - The discharge and subsequent charge of a secondary battery such that it is restored to its fully charged state. Duty cycle - Operating parameters of a cell or battery including factors such as charge and discharge rates, depth of discharge, cycle length, and length of time in the standby mode. Electrode - Electrical conductor and the associated active materials at which an electrochemical reaction occurs. Also referred to as the positive and negative plates in a secondary cell. Electrolysis - Chemical dissociation of water into hydrogen and oxygen gas caused by passage of an electrical current. Electrolyte - Medium which provides the ion transport function between the positive and negative electrodes of a cell. Equalizing charge - Charge applied to a battery which is greater than the normal float charge and is used to completely restore the active materials in the cell, bringing the cell float voltage and the specific gravity of the individual cells back to “equal” values.