Glossary of Battery Terms

Active material

Electrode materials in a battery which cause an electrochemical reaction to generate electricity. For Example:

  • Battery Positive material Negative material
  • LR Manganese Dioxide Zinc
  • CR Manganese Dioxide Lithium

Ageing

A finished or semi-finished battery is store under specified conditions for a specified period.

Capacity

Capacity (Ah, mAh) is the product of the discharge current (A, mA) and discharge time (h).

Note: Because manganese dry batteries and alkaline manganese batteries are often used for heavy-duty applications, the discharge time at a specific load is usually mentioned instead of the capacity.

Closed circuit voltage (CCV)

Voltage across the terminals of a battery when it is on discharge. As a battery has an internal resistance, CCV is lower than OCV and CCV becomes lower with a range of current.

Charge

Operation during which a reverse reaction of discharge occurs when electrical energy is received from an external source.

Discharge

Operation during which a battery delivers current to an external circuit.

Discharge characteristics (Discharge curve)

Change of a battery voltage with discharge.

Duration time (Duration period)

Time until a battery voltage exceeds the end-point voltage during discharge.

End-point voltage (End voltage, Cutoff voltage, Final voltage)

Specified closed circuit voltage at which a service output test is terminated.

Energy Density

Usable energy of a battery per unit volume or unit weight. The former is called volumetric energy density (Wh/l); the latter gravimetric energy density (Wh/kg).

Expiry date

Expiration of guarantee period of a primary battery determined by each manufacturer conforming to the IEC. Because a secondary battery can be used over again by charging, it is unnecessary to show this.

Note: IEC (International Electrotechnical Commission) is a worldwide organization of standardization comprised of all national electrotechnical committees.

Electrolyte

Medium in a battery which causes ions to move to create an electrochemical reaction. Either water or non-aqueous solution is used as solvent. The latter is called non-aqueous electrolyte solution, either organic or inorganic.

Internal resistance

Resistant component in a battery that makes discharge reaction slow.

Initial test

Test conducted within 2 months of the production month.

Internal short circuit

Direct contact electrically between the positive electrode and negative electrode caused by damage to the separator or gasket, or the presence of a conductor piercing the separators. A battery will become completely exhausted before use.

Load

External device or method through which a battery is discharged.

Leakage resistance

Enduring characteristics against leakage.

Nominal voltage

Suitable approximate value of voltage used to identify the voltage of a battery. For example:

  • Alkaline manganese battery; 1.5V
  • Lithium manganese dioxide battery; 3.0V

Open circuit voltage (OCV)

Voltage across the terminals of a battery when no external current is flowing.

Over discharge

Continue to discharge after a battery voltage drops below its end-point voltage.

Primary battery

Source of electrical energy obtained by the direct conversion of chemical energy and not designed to be charged by any other electrical source.

Polarization

Voltage deviation from equilibrium caused by charge or discharge.

Rechargeable battery (Secondary battery)

Source of electrical energy obtained by the direct conversion of chemical energy designed to be charged by any other electrical source. It is also called a storage battery or accumulator.

Self discharge

Decreasing capacity during storage without load, caused by chemical reaction in a battery. The higher the temperature during storage, the greater the rate of self discharge.

Storage

Store the battery under specified conditions.

Short circuit current

Surges of current across the terminals of a battery when it is short-circuited.

Test after storage

Test conducted within 2 weeks after storage.

Utilisation factor

Ratio of usable capacity against theoretical capacity.