Battery Glossary of Terms

The negative electrode of a cell.
Button Cell:
A small round or elliptical cell whose diameter is greater than its height.
Capacity is the product of the discharge current Amps (A) or milli Amp (mA) and the discharge time (h) at a given load and is expressed in Amp-Hours (Ah) or milli Amp-Hours (mAh).
The positive electrode of a cell.
A single encased electrochemical unit (one positive and one negative electrode) which exhibits a voltage differential across its two terminals. Under the Model Regulations of Tests and Criteria (See UN38.3 Tests), to the extent the encased electromechanical unit meets the definition of a "cell" herein, is a "cell", not a "battery", regardless of whether the unit is termed a "battery" or a "single cell battery" outside of the Model regulations.
CE Mark:
The CE mark (Abbreviation of Conformité Européenne) is a mandatory conformity mark for products placed on the market in the European Community. With the CE mark on the product, the manufacturer ensures that the product conforms to the requirements of the applicable EC directive.
Refers to the basic material of the negative electrode. Example: Zinc, Lithium, Nickel.
Closed circuit voltage - CCV:
Voltage across the terminals of a battery under load when there is external current flowing.
Coin cells:
A small cell whose diameter is greater than its height. Coin cells are typically lithium chemistry.
One sequence of fully charging and fully discharging a rechargeable cell or battery.
Operation during which a battery delivers current to an external circuit or load.
Discharge characteristics - Discharge curve:
Graphical representation of the change in output voltage over time under various loads and/or ambient temperature.
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.
End-point voltage:
Specified closed circuit voltage at which a cell is terminated. Also referred to as "cutoff” or "final” voltage.
Energy Density:
Available energy of a battery per unit volume or unit weight.
The International Air Transport Association (IATA) is an international trade group comprised of some 240 airlines and is headquartered in Montreal Quebec, Canada. IATA's stated mission is to represent, lead and serve the airline industry. The main aim of IATA is to provide safe and secure transportation to its passengers. IATA annually publishes the IATA Dangerous Goods Regulations (DGR), which are modeled after the ICAO Technical Instructions. (The 54th Edition became effective on 1-1-2013.) Working closely with governments in the development of the regulations, including ICAO and other national authorities, IATA ensures that the rules and regulations governing dangerous goods transport are both effective and efficient. The U.S. Department of Transportation (DOT) does not officially recognize or enforce the IATA Dangerous Goods Regulations. Instead, the DOT has the authority to enforce the ICAO Technical Instructions.
Internal Impedance:
Internal impedance of a cell that increases as the cell ages or is discharged. This is measured by a 1000Hz Bridge, also called internal resistance. Typical internal impedance of a cell is <100µOhms.
The escape of material from a cell or battery. The most common leakage is electrolyte, which is either very flammable or very corrosive.
Lithium content:
The mass, in grams, of lithium metal contained within the anode of lithium metal or lithium alloy cell. These are, for the most part, primary cells. The lithium content of a lithium battery is the sum of the lithium mass of the anodes of all the cells in the battery.
External device or method through which a battery is discharged.
Nominal voltage:
Approximate midpoint voltage, during discharge, of a fully charged battery cell. This varies by chemistry with common examples below:
  • Alkaline manganese primary - 1.5V
  • Zinc Carbon Primary - 1.5V
  • Lithium manganese dioxide primary - 3.0V
  • Lithium thionyl chloride primary - 3.6V
  • Nickel cadmium rechargeable battery - 1.2V
  • Nickel metal-hydride rechargeable - 1.2V
  • Nickel Zinc rechargeable - 1.6V
  • Lithium-ion rechargeable - 3.7V
  • Lithium-prismatic rechargeable - 3.7V
  • Lithium-polymer rechargeable - 3.7V
  • Silver Oxide Primary - 1.55V
  • Zinc Air Primary - 1.45V
Open circuit voltage - OCV:
Voltage across the terminals of a battery when no external current is flowing and not under load. The OCV is typically higher than a battery's nominal voltage.
Over discharge:
To discharge a cell to a voltage below its end-point voltage.
Packing Instructions:
The ICAO Technical Instructions and the IATA Dangerous Goods Regulations require compliance to specific Packing Instructions (PIs) in order to offer lithium-metal primary cells and batteries and lithium-ion rechargeable batteries for transport in passenger and cargo aircraft.
  • PI 965: UN3090 Lithium-metal primary cells and batteries.
  • PI 966: UN3091 Lithium-metal primary cells and batteries shipped with equipment.
  • PI 967: UN3091 Lithium-metal primary cells and batteries installed in equipment.
  • PI 968: UN3480 Lithium-ion rechargeable cells and batteries.
  • PI 969: UN3481 Lithium-ion rechargeable batteries shipped with equipment.
  • PI 970: UN3481 Lithium-ion rechargeable batteries installed in equipment.
Protection Circuit Module - PCM:
The safety circuit installed in all lithium-ion and lithium-polymer rechargeable battery packs to control over-charge, over-discharge and short circuit of the cells within the pack. This circuit is mandated by the UN Manual of Tests and Criteria, paragraph 38.3, Rev. 5.
Protective Devices:
Devices, such as fuses, diodes and current limiters which interrupt the current flow, block the current flow in one direction or limit the current flow in an electrical circuit.
A cell or battery which is not designed to be charged and discharged.
Rated Capacity:
The capacity, in ampere-hours (Ah) of a cell or battery as measured by subjecting it to a load, temperature and cut-off voltage point specified by the manufacturer.
Decreasing capacity during storage without load, caused by chemical reaction in a battery. The higher the temperature during battery storage, the greater the rate of self-discharge.
SMBus is the System Management Bus as defines by the Intel Corporation in 1995. It is used in personal computers and servers for system management communications, including battery charge status.
UN3090, UN3091, UN3480 & UN3481:
The IATA Dangerous Goods Regulations and the U.S. Code of Federal Regulations (49CFR Part 172(c)(1)) classify lithium-metal primary and lithium-ion rechargeable cells and batteries as Dangerous Goods; and must be shipped in passenger and cargo aircraft in accordance with specific packing instructions. (See Packing Instructions)
  • UN3090: Lithium-metal primary cells and batteries.
  • UN3091: Lithium-metal primary cells and batteries shipped with or in equipment.
  • UN3480: Lithium-ion rechargeable cells and batteries.
  • UN3484: Lithium-ion rechargeable cells and batteries shipped with or in equipment.
UN 38.3 Tests:
In order to offer for transport in passenger and cargo aircraft, lithium-metal primary cells and batteries and lithium-ion rechargeable cells and batteries must comply with Packing Instructions 965 through 970 (as applicable) in The ICAO Technical Instructions "Recommendations on the Transport of Dangerous Goods Manual of Tests and Criteria". This packing instruction includes mandatory provisions for the testing of lithium metal and lithium-ion cells and batteries (Sub-section 38.3).
A safety device built into almost all cells designed to release internal pressure in the case of overcharge, over temperature and other abuses. The vent will preclude rupture or disassembly.
The release of excessive internal pressure from a cell or battery in a manner intended by design to preclude rupture or disassembly. Venting may also release electrolyte.
A cell or battery's nominal voltage multiplied by its rated capacity in amp-hours.
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