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Active Material

Specific chemically reactive material at the positive or negative electrode that takes part in the charge and discharge reactions.

Air Cell

Battery system which utilizes oxygen in combination with catalyzed carbon as the cathode and zinc as the anode to produce electricity.

Alkaline Battery

Primary battery which employs alkaline aqueous solution for its electrolyte.


Product of current (amperes), multiplied by time (in hours) the circuit is closed (current flowing).


The negative electrode. The electrode at which an oxidation reaction (loss of electrons) occurs.


American National Standards Institute. Sets battery standards for safety, size, performance, etc.


The average current withdrawn from a cell or battery during discharge; usually approximated by calculating the current at 50% depth of discharge.


Technically, a battery consists of two or more series or parallel connected galvanic cells. Frequently, however, a single cell is called a battery.

Button Cell

See miniature battery


Output capability over a period of time; expressed in ampere-hours.

Carbon Zinc

A generic term for primary dry batteries of the LeClanche or Zinc Chloride systems.


The positive electrode. The electrode at which a reduction reaction (gain of electrons) occurs.


A primary galvanic unit which converts chemical energy directly into electric energy.  Typically consists of two electrodes of dissimilar material isolated from one another electronically in a common ionically conductive electrolyte.

Cell Reversal

Reversing polarity of terminals of a cell or battery due to over discharge.

Charge, State of

Condition in terms of the rated capacity remaining at a given point in time.


Process of supplying electrical energy for conversion to stored chemical energy.

Closed-circuit voltage (CCV)

Voltage as measured of a cell or battery under a specific discharge load and time interval.

Coin Cell

See miniature battery


Electronic connection between the battery electrode and the external circuit.

Constant Current

Charging or discharging method in which current does not change appreciably in magnitude regardless of battery voltage or temperature.

Constant Power

Power remains stable regardless of battery voltage.  As battery voltage changes, the current is adjusted to maintain targeted power value.  (See below for power definition.)

Constant Power

Power remains stable regardless of battery voltage.  As battery voltage changes, the current is adjusted to maintain targeted power value.  (See below for power definition.)

Constant Resistance

Commonly found in devices which maintain a constant resistance throughout the battery discharge.  As the battery is drained, both voltage and current decline.

Continuous Test Regimen

Charge and/or discharge profile that is defined without rest periods. 

Cutoff Voltage

Voltage at the end of useful discharge. Battery voltage below which the connected equipment will not operate or below which operation is not recommended.


One sequence of activity. This can be a pulse or continuous drain.

Cylindrical Battery

A battery whose height is greater than its diameter. The term cylindrical is also used to describe batteries made up of cylindrical cells.

Deep Discharge

Discharge of the battery to below the specified voltage cutoff before the battery is replaced or recharged.

Depth of Discharge (DOD)

The percent of rated capacity to which a cell or battery is discharged.


Withdrawal of electrical energy from a cell or battery, usually to operate connected equipment.

Discharge Rate

The current at which a cell or battery is discharged.


Withdrawal of current from a cell or battery.

Drain, Heavy

Generally, current that would discharge a battery within one day at room temperature.

Drain, Light

Generally, current that would discharge a battery after one month at room temperature.

Drain, Moderate

Current that would discharge a battery in approximately one week at room temperature.

Dry Battery

A battery in which the electrolyte is immobilized, being either in the form of a paste or gel or absorbed into the separator material.

Duty Cycle

The time duration and use frequency during which a battery is drained (i.e. 2 hours/day).


Conducting body at which the electrochemical reaction occurs.


May be solid or liquid. Usually an aqueous salt solution that permits ionic conduction between the positive and negative electrodes


Output capability; ampere-hour capacity times average closed-circuit discharge voltage, expressed as watt-hours.

Energy Density

Ratio of battery energy to weight or volume (watt-hours per kilogram or watt-hours per cubic centimeter).

Functional End Point (FEP)

Voltage below which battery-operated equipment will not function properly.


International Electro Chemical Commission. A worldwide organization for standardization in the electrical and electronic fields.

Impedance (Z)

The total opposition that a battery offers to the flow of alternating current. Impedance is a combination of resistance and reactance.

Initial Drain

Current that a cell or battery supplies when first placed on load. Also referred to as starting drain.

Internal Resistance (Ri)

Opposition to direct current flow within a battery, with the battery as source, causing a drop in closed-circuit voltage proportional to the current drain from the battery.

Intermittent Test Regimen

Charge and/or discharge profile that is defined with specified rest periods.


A Carbon Zinc battery with slightly acidic electrolyte consisting of ammonium chloride and zinc chloride in water.

Miniature Battery

A button or coin shaped battery whose diameter is greater than its height. The term “Miniature” is also used to describe batteries made up of miniature cells.

Open-Circuit Voltage (OCV)

The no load voltage of a cell or battery measured with a high resistance voltmeter.


Electrical potential reduction of electrodes typically arising from prolonged or rapid discharge of the battery.


A cell or battery designed to deliver its rated capacity once and be discarded; not designed to be recharged.

Rated Capacity

The average capacity delivered by a cell or battery on a specified load and temperature to a voltage cutoff point, as designated by the manufacturer; usually an accelerated test approximating the cell or battery’s capacity in typical use.

Rate Sensitivity

Typically refers to battery performance under various discharge loads with operating voltage being the defining characteristic

Rating Drain

The specified current withdrawn form a cell or battery to determine its rating capacity.


Capable of being recharged; refers to secondary cells or batteries.


A cell or battery designed to be recharged.

Self Discharge Rate

The rate at which a cell or battery loses its capacity when standing idle.

Service Maintenance

The percent of fresh rated capacity remaining after a specified period of time.


The amount of time a cell or battery will retain a specified percent of its rated capacity, typically under ambient storage conditions.

Silver Oxide

Battery containing cathode of silver oxide, anode of zinc and highly alkaline electrolyte consisting of NaOH or KOH.

Trickle Charge

A method of recharging in which a secondary battery is either continuously or intermittently connected to a constant current supply that maintains the battery in a fully or near full charged condition.

Zinc Chloride

A Carbon Zinc battery with a slightly acidic electrolyte consisting mainly of zinc chloride in water.