Battery glossary

Accumulator
Commonly called 'rechargeable battery', an accumulator is an electrochemical device. When it is recharged, it converts electrical energy into chemical energy. When a device requires power, the accumulator converts the chemical energy back into electric energy.

Ampere
Basic unit of electrical current strength.

Battery
Two or more accumulators connected together.

Capacity
Quantity of power a rechargeable battery can store and can supply back to a device. The higher the battery's capacity (mAh), the longer it will last in an electronic device.

Charge
Operation during which a cell or battery receives electrical energy from an external circuit. This electrical energy is converted into chemical energy.

Charging current
The charging current is measured in mA (milliamps). It is the number of electrons flowing through the charger wires.

Current
Movement of electrical charges in an electrical field. Rechargeable batteries only use direct current.

Cycle
Discharge sequence followed by a charge, or a charge followed by a discharge of a battery under specific conditions.

Cylindrical Cell
ell of circular cross-section in which the overall height is greater than the diameter.

Delta V
Detection of the voltage drop indicating a battery is fully charged.

Discharge
Operation during which a battery delivers current to an external circuit by conversion of chemical energy into electrical energy.

Discharge rate
Current at which a battery is discharged.

Discharge voltage
Voltage between the terminals of a cell or battery under load, during discharge.

Electrode
Positive or negative plate holding active materials.

Electrolyte
Liquid which provides ionic conductivity between the positive and negative electrodes.

Final voltage
Specified voltage at which the discharge of a battery is considered finished (cut-off).

Life span
Number of cycles a rechargeable battery will take before being non-operational.

Li-Ion
Mixture of Lithium and Ion. They produce 40% to 50% more power than Ni-MH rechargeable batteries with a similar capacity and are considerably lighter. Ideal for mobile phones and laptops, video cameras and digital cameras.

Memory effect
Only Ni-Cd batteries are affected by memory effect. If a Ni-Cd battery is recharged before being fully discharged, the battery stores an unwanted discharge stage for the next cycle in its memory, even though capacity is still available 'below this'. To avoid this memory effect, Ni-Cd batteries must be fully discharged every 5 to 10 charges.

Milli-amp-hour (mAh)
The capacity of a rechargeable battery is measured in mAh.

Ni-Cd (Nickel Cadmium)
Mixture of Nickel and Cadmium. They are ideal for most types of domestic devices.

Ni-MH (Nickel Metal hydride)
Mixture of Nickel and Metal Hydride. They are 2 to 3 more powerful than cadmium-based rechargeable batteries and have no memory effect. They are ideal for usage in digital devices.

Overcharge
Continued charging after the full charge of a cell or battery.

Prismatic cell
Differs in external appearance from the round cell. Prismatic cells are block-shaped and are therefore very flat.

Primary Cells
Cell which is not intended for recharging.

Separator
Device used for the physical separation and electrical isolation of electrodes of opposing polarities.

Trickle charge
Charge supplied to battery at a continuous low rate to keep it fully charged without overcharging it.

Temperature cut-off
Detection method of overheating battery in case of overcharge. It stops the charger or reduces the charging current.

Venting valve
Safety valve in the cell which opens in case of overpressure and closes again automatically when normal pressure has been restored.

Volt (V)
Unit of measurement for electrical voltage.

Voltage Cut-Off
Detection method of a specified voltage at which the charger will stop the charge or discharge of rechargeable batteries.