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Ampere-Hour Capacity
The quantity of electricity measured in ampere-hours (Ah) that can be delivered by a cell or battery under specified conditions.

The electrode in an electrochemical cell where oxidation takes place. During discharge, the negative electrode of the cell is the anode. During charge, the positive electrode is the anode.

Battery or Pack
Technically, two or more electrochemical cells electrically interconnected in an appropriate series/parallel arrangement to provide the required operating voltage and current levels. Frequently, however, the term “battery” is applied to a single cell.

A cylindrical cell design utilizing an internal cylindrical electrode and an external electrode arranged as a sleeve inside the cell container.

The total number of ampere-hours or watt-hours that can be withdrawn from a fully charged cell or battery under specified discharge conditions.

The electrode in an electrochemical cell where reduction takes place. During discharge, the positive electrode of the cell is the cathode. During charge in a rechargeable battery, the negative electrode is the cathode.

The basic electrochemical unit used to generate or store electrical energy.

The conversion of electrical energy, provided in the form of electrical current from an external source, to restore the chemical energy in a cell or battery.

A process that utilizes a series of heavy discharges and recharges on a battery to assure best performance.

Constant Current
A battery discharge regime whereby the current drawn during the discharge remains constant.

Constant Power
A battery discharge regime whereby the current during the discharge increases as the battery voltage decreases.

Continuous Test
A test in which a battery is discharged to a prescribed end point voltage with no interruption.

Current Drain
The current taken from a battery during discharge.

Cutoff Voltage
The battery voltage at which the discharge is terminated. The cutoff voltage is specified by the battery manufacturer and is generally a function of discharge rate.

A sequence where a charged battery is discharged and recharged.

Cycle Life
For secondary batteries, the number of cycles under specified conditions that are available from before it fails to meet specified criteria as to performance.

Cylindrical Cell
A cell in which the positive and negative plates are rolled up and placed into a cylindrical container (as opposed to stacking the plates in a prismatic cell design).

The change from chemical energy of a battery into electrical energy, and the withdrawal of the electrical energy into a load.

Discharge Rate
The rate, usually expressed in amperes, at which electrical current is taken from the battery.

The current withdrawn from a battery during discharge.

Dry Cell
A cell in which the electrolyte is immobilized. The term “dry cell” is often used to describe the Leclanché cell.

Duty Cycle
The operating regime of a battery including factors such as charge and discharge rates, depth of discharge, cycle duration, and length of time in the standby mode.  

The site, area or location at which electrochemical processes occur.

The medium that transports the ions carrying the charge between the electrodes during the electrochemical reaction in a battery.

The output capability of a cell or battery expressed in watt-hours.

Fast Charge
Typical fast charge time for a NiCd is 1 to 3 hours. The fast-charger detects the state of charge and switches to trickle charge when full-charge is reached.

The use of batteries in which they are charged by an application to be ready for use if the primary power to the application fails. Also called backup or standby.

A safety device used for cutting off an electrical current in the event of an abusive condition.

Hourly Rate
A discharge rate, in amperes, of a battery that will deliver the specified hours of service to a given cutoff voltage. 

Internal Impedance
The opposition exhibited by a circuit element (cell or battery) to the flow of an alternating current (A.C.) of a particular frequency as a result of resistance, induction and capacitance.

Internal Resistance (IR)
The opposition exhibited by a circuit element (cell or battery) to the flow of direct current (D.C.). In a cell, the internal resistance is the sum of the ionic and electronic resistances of the cell components.

Lead Acid Battery
Invented in 1859, it is still the most popular battery used today. Its main application is for the automobile industry, although it has a growing number of other applications. Its advantages are low cost, high voltage per cell and good capacity life. Disadvantages are poor low temperature characteristics, it is relatively heavy, and it cannot be left in a discharged state for too long without being damaged.

Limiting Current
The maximum current drain under which the particular battery will perform adequately under a continuous drain. The rate is based on whatever drain rate reduces the running voltage to 1.1 volts.

Lithium Battery
A primary battery (non-rechargeable) that is quickly entering mainstream electronic designs, particularly in consumer, portable equipment and non-volatile memory back up applications where small size, long life and low cost are the primary requirements. Lithium batteries have superior cold temperature performance and a shelf life of 5-10 years. Lithium primaries are available in many chemistries, each with their own particular attributes.

Lithium Ion Battery (Li Ion)
One of the newer rechargeable battery technologies, Li Ion batteries can deliver 40% more capacity than comparably sized NiCd batteries and are one of the lightest rechargeable batteries available. Li Ion batteries are the batteries of choice in notebook computer, wireless telephones and many camcorder models. They are also one of the more expensive rechargeable technologies.

Lithium Manganese Dioxide Battery (LiMnO2)
A primary battery (non-rechargeable), the Lithium Manganese Dioxide battery offers high energy density, reliability and excellent shelf life. Less volatile and less costly than Lithium Sulfur Dioxide, LiMnO2 batteries offer a good balance of performance and safety. Their uses include keyless entry systems and memory back up.

Lithium Thionyl Chloride Battery (LiSOCl2)
A primary battery (non-rechargeable), the Lithium Thionyl Chloride battery has the highest energy density of all Lithium types. Service life is typically 15 to 20 years. These cells are best suited for applications having low continuous-current and moderate pulse-current requirements. Their long service life and low self-discharge rate make them ideally suited for use in harsh or inaccessible environments like utility monitoring and electronic toll collection.

Load Current
The discharge current delivered to a battery-powered device. 

Milliampere-hour (mAh)
A battery capacity or rating. A battery that provides a current of 1000mAh for one hour is rated at 1000mAh (or 1 Ah).

An electrode or a terminal that has an excess of electrons.

Nickel Cadmium Battery (NiCd)
One of the most proven and historically widely used rechargeable batteries. Very dependable and robust, but contain cadmium and have relatively low capacity when compared to other rechargeable systems. Very good high rate discharge capabilities make them very popular in high drain applications such as power tools.

Nickel Metal Hydride Battery (NiMh)
Interchangeable with most NiCd batteries, nickel metal hydride (NiMh) batteries generally deliver greater capacity than NiCds and are more environmentally friendly than NiCds, since they do not contain cadmium. NiCd batteries are used in many wireless phones and camcorders.

Nominal Voltage
The characteristic operating voltage or rated voltage of a battery.

A measure of electrical resistance that causes one volt to produce a current of one ampere.

Open-Circuit Voltage (OCV)
The difference in potential between the terminals of a cell when the circuit is open (no-load condition). 

The interconnection of cells or batteries where all the like terminals are connected together. This results in increased capacity.

The phenomenon by which a metal, in conditions of thermodynamic instability, remains unattacked because of modified or altered surface conditions.

In electricity, the quality of having two charged poles, one positive and one negative.

A terminal or electrode that has a shortage of electrons.

Primary Battery
A battery which is not intended to be recharged and is discarded when it has delivered all of its electrical energy. (A non-rechargeable battery.)

Prismatic Cell
The positive and negative plates are stacked rather than rolled as done in a cylindrical cell.

Pulse Current
A periodic current drain of higher than normal drain rates.

Rapid Charge
A charge time that is between slow charge and fast charge (typically 3 to 6 hours for a NiCd).

Rated Capacity
The number of ampere-hours a battery can deliver under specific conditions (for example, rate of discharge, end voltage, temperature). Rated capacity is usually specified by the battery manufacturer.

Rechargeable Battery
A galvanic battery that, after discharge, may be restored to the fully charged state by the passage of an electrical current through the cell in the opposite direction to that of discharge.

One or more deep discharge cycles below 1.0 volt/cell at a very low, controlled current. Recondition helps to revert large crystals to small desirable sized, often restoring the battery to its full capacity.

The degree to which the flow of electrons is opposed by the material the electrons must pass through. Resistance is expressed in ohms. 

Safety Vent
A safety mechanism designed into a cell that activates under specific conditions of abuse to relieve internal pressure.

Secondary Battery
A battery that can be recharged and reused many times.

The loss of capacity of a battery during storage due to internal chemical action.

The interconnection of cells where the positive terminal of the first is connected to the negative terminal of the second, and so on. This results in increased voltage.

Shelf Life
The duration a cell can be kept in storage under specified conditions and still retain its ability to give a specified performance.

Short Circuit
An unwanted electrical connection between a negative and positive source. Short circuits can damage the battery and equipment and can cause fire.

Silver/Oxide Battery
A primary battery (non-rechargeable) it is a major contribution to miniature power sources, and is well suited for hearing aids, instruments, photoelectric exposure devices and electronic watches. These cells are primarily made in the smaller “button” sizes.

Smart Battery
Battery with internal circuit enabling some communication between the battery and the user. Some batteries feature a capacity indicator only; others offer an external bus to interface with the equipment, the battery power and the intelligent charger.

Spiral Wound
An electrode structure of high surface area created by winding the electrodes and separator into a spiral, jelly-roll configuration.

Temperature Cutoff
A safety device that senses temperature in a battery and opens or cuts off the electrical circuit if the specified temperature is exceeded, thus preventing a further rise in temperature.

A device at the end of a cell or wire at which a connection to an adjoining cell or wire is established or broken.

A temperature sensitive resistor usually made from specially processed oxides that are used to sense end of charge temperature rises and terminate high rate charging.

Trickle Charge
A charge at a low rate, balancing losses through local action and/or periodic discharge, to maintain a cell or battery in a fully charged condition. 

A unit of measuring electric potential. Voltage is the difference in electrical energy between two points.

Voltage Delay
Time delay for a battery to deliver the required operating voltage after it is placed under load.

Voltage Regulator
A device that regulates the output of a generator or alternator by controlling the current and voltage.

A measurement of energy, arrived at by multiplying the voltage by the amperage.

Zinc/Air Battery
A primary battery (non-rechargeable) that was commonly used for applications such as watches and hearing aids. In relation to their physical size, Zinc/Air batteries store more energy per unit of weight (in terms of 220 W h/kg) than any other primary type.