Battery documentation uses abbreviations for cell formats, electrical quantities, chemistries, test methods, vehicle systems, and organizations. The same letters can also have different meanings in different engineering contexts. This reference groups common terms alphabetically from the 18650 cell designation through the P range, while identifying where context is needed.
Units and symbols are not interchangeable. Current is measured in amperes, voltage in volts, power in watts, energy in watt-hours or joules, and capacity in ampere-hours. A battery rating, test result, or charging specification should therefore be read together with its unit, test conditions, and definition.
Symbols and Abbreviations from 18650 Through C
Cell formats, units, and basic electrical terms
| Term | Meaning and technical use |
|---|---|
$ | Currency symbol. It is not a battery or electrical unit. |
18650 | A cylindrical cell format designation. The numbers describe an approximate 18 mm diameter and 65 mm length; the format does not specify chemistry, capacity, voltage, or protection circuitry. |
A | Ampere, the SI unit of electric current. |
Ah | Ampere-hour, a unit of electric charge commonly used to state battery capacity. One ampere-hour represents one ampere supplied for one hour, subject to the specified discharge conditions. |
AC | Alternating current. The current periodically changes direction, unlike direct current. |
B | In some battery documents, B can identify a battery, bus, or magnetic-flux-related quantity. Its meaning depends on the diagram or standard. |
C | Coulomb, the SI unit of electric charge; it can also denote capacitance-related or chemistry-specific terms. One ampere-hour corresponds to 3,600 coulombs. |
F | Farad, the SI unit of capacitance. A capacitor has a capacitance of one farad when one coulomb changes its voltage by one volt. |
Hz | Hertz, the unit of frequency. One hertz equals one cycle per second. |
J | Joule, the SI unit of energy. One joule equals one watt-second. |
K, °C, and °F | Temperature notation. Kelvin is an absolute temperature scale; degrees Celsius and degrees Fahrenheit are practical temperature scales. Temperature conditions should accompany battery test results. |
V | Volt, the unit of electrical potential difference. |
W | Watt, the unit of power. Power is the rate at which energy is transferred. |
Wh | Watt-hour, a unit of energy. It should not be confused with W, which measures power. |
A rough battery-energy relationship is energy in watt-hours = nominal voltage × ampere-hours. Actual delivered energy depends on voltage variation, current, temperature, cutoff limits, efficiency, and the test method.
Battery states, charging, and management
| Term | Meaning and technical use |
|---|---|
ASoC or ASOC | Actual state of charge. It describes the estimated charge actually present, as opposed to a displayed or modeled value. |
ASoH | Actual state of health. It describes the estimated condition or remaining capability of a battery relative to a defined reference condition. |
BESS | Battery energy storage system. A BESS normally includes cells or modules together with power conversion, controls, thermal management, monitoring, and safety equipment. |
BMS | Battery management system. A BMS monitors cell and pack conditions and may control balancing, contactors, charging, discharge limits, fault handling, and communications. |
CC | Constant current. During this charging or testing phase, the control system attempts to maintain a specified current. |
CCCV | Constant-current/constant-voltage charging. The charger first regulates current and then regulates voltage while current normally tapers. |
CCV | Closed-circuit voltage, the voltage measured while current is flowing. It varies with current, internal resistance, temperature, state of charge, and measurement timing. |
C-rate | A normalized current expressed relative to rated capacity. A 1C current would theoretically charge or discharge the rated capacity in one hour, but the applicable rating and test conditions must be stated. |
DoD | Depth of discharge, the portion of usable capacity removed from a battery. It is related to state of charge but is not automatically identical to the percentage shown by every battery monitor. |
OCV | Open-circuit voltage, measured with no intended external current flowing after an appropriate rest period. OCV is chemistry- and condition-dependent and is not the same as loaded voltage. |
SOC | State of charge, an estimate of remaining charge relative to a defined usable or rated capacity. |
SOH | State of health, an estimate of battery condition relative to a reference battery or specified performance criterion. |
Organizations, transport, and safety terms
| Term | Meaning and technical use |
|---|---|
AAMI | Association for the Advancement of Medical Instrumentation. Its standards and guidance concern medical equipment, including areas that can overlap with batteries and power systems. |
A4WP | Alliance for Wireless Power, an organization associated with wireless-power technology. |
ADAC | Allgemeiner Deutscher Automobil-Club, the German automobile association. |
AGV | Automated guided vehicle. AGVs commonly use rechargeable battery systems for industrial transport. |
ALPA | Air Line Pilots Association. The abbreviation may occur in aviation or transport documentation rather than battery engineering. |
ANSI | American National Standards Institute. ANSI coordinates and approves standards but is not itself a battery chemistry or test method. |
APU | Auxiliary power unit. In vehicles and aircraft, an APU supplies auxiliary power independently of the main propulsion system. |
BCG | Battery Council Group in some battery-industry contexts; the exact expansion should be checked against the document or organization using it. |
BCI | Battery Council International, an organization associated with automotive and industrial battery terminology and testing. |
CARB | California Air Resources Board. Its regulations include vehicle emissions and zero-emission vehicle requirements. |
CAN Bus | Controller Area Network bus, a robust serial communications network widely used in vehicles, battery packs, chargers, and industrial equipment. |
CEC | California Energy Commission in energy-efficiency and equipment-regulation contexts. CEC can also mean a certificate or competency term in other technical or maritime documents; context is required. |
CNG | Compressed natural gas. It is a gaseous fuel and should not be confused with battery-electric energy storage. |
DIN | Deutsches Institut für Normung, the German Institute for Standardization. DIN also appears in references to German or European test procedures. |
DGR | Dangerous Goods Regulations. The abbreviation is commonly used for requirements governing transport of hazardous materials, including lithium batteries. |
DOE | U.S. Department of Energy. |
DOT | U.S. Department of Transportation; the abbreviation may also refer to a national transport department in another jurisdiction. |
DCP | Depending on context, discharge control point, dedicated charging port, or another defined control term. The document’s glossary or standard should control the expansion. |
DGP | Dangerous goods package or a similarly defined dangerous-goods term in transport documentation. Verify the governing regulation before using the expansion operationally. |
Additional battery and electrochemical terms
| Term | Meaning and technical use |
|---|---|
AEDLC | Asymmetric electrochemical double-layer capacitor, a capacitor-related term used for devices whose electrodes or charge-storage mechanisms are not symmetrical. |
AFC | Alkaline fuel cell. It uses an alkaline electrolyte and is a fuel-cell system rather than a rechargeable battery. |
AGM | Absorbent glass mat. In an AGM lead-acid battery, the electrolyte is held in a fiberglass mat separator. |
CID | Current interrupt device. A protective component designed to interrupt current when an internal pressure or fault condition reaches its operating threshold. |
CNT | Carbon nanotube. CNTs may be used as conductive or structural additives in electrodes and other components. |
DLC | Double-layer capacitor, also called an electrochemical double-layer capacitor in suitable contexts. |
dT/dt | Rate of temperature change with time. Battery protection systems may monitor rapid temperature rise as a fault indicator. |
CEC | In addition to California Energy Commission, CEC may be a certificate or competency abbreviation in a different industry. Do not assume one expansion without context. |
Battery and Electrical Abbreviations from D Through L
| Term | Meaning and technical use |
|---|---|
DC | Direct current, which flows in one direction. Batteries provide DC at their terminals. |
DCA | Depending on the application, direct-current amperes or a defined current-administration or charging term. Use the equipment specification for the exact meaning. |
DMFC | Direct methanol fuel cell. Methanol is supplied directly to the electrochemical cell rather than first being reformed into hydrogen externally. |
EBM | Electronic battery monitor or an equipment-specific battery-management term. The expansion should be taken from the applicable system documentation. |
EIS | Electrochemical impedance spectroscopy. EIS measures electrical response over a range of frequencies to study resistance, reaction, and transport behavior. |
ELC | Electric load control or another defined electrical-control term; the exact meaning is application-specific. |
EMF | Electromotive force. It represents the energy supplied per unit charge by a source under defined conditions and is not automatically identical to terminal voltage under load. |
ESS | Energy storage system. ESS is broader than BESS and may include batteries, capacitors, thermal storage, pumped storage, or other technologies. |
EV | Electric vehicle. An EV uses an electric drivetrain and a rechargeable traction battery or another electric energy source. |
FC | Fuel cell, or sometimes fuel-cell vehicle when used in a transport context. A fuel cell converts supplied reactants into electricity electrochemically. |
FCC | Full charge capacity in battery monitoring. FCC can also mean the U.S. Federal Communications Commission, so battery context is essential. |
HEV | Hybrid electric vehicle. It combines an electric drivetrain or motor with another propulsion system, commonly an internal-combustion engine. |
ICE | Internal-combustion engine. |
IPF | In battery and electrochemical literature, IPF may identify an interfacial or impedance-related parameter; it is not a universal expansion. Confirm it in the source specification. |
IPP | Independent power producer in energy-market usage; other industries use the same letters differently. |
IS | Isolation system, insulation monitoring system, or another defined term. In high-voltage battery systems, the surrounding safety documentation determines the meaning. |
LCO or LiCoO₂ | Lithium cobalt oxide. LCO is a lithium-ion cathode material; the abbreviation does not by itself define the complete cell design. |
LFP or LiFePO₄ | Lithium iron phosphate, a lithium-ion cathode chemistry. |
Li-ion | Lithium-ion. It describes a family of rechargeable cells using lithium-ion electrochemical reactions, not one single cathode chemistry. |
LiFeS₂ | Lithium iron disulfide, commonly used as a primary lithium cell chemistry. It should not be confused with rechargeable lithium-ion phosphate cells. |
LiMnO₂ | Lithium manganese dioxide, generally associated with primary lithium cells. |
LMO or LiMn₂O₄ | Lithium manganese oxide, a lithium-ion cathode material. LMO and LiMnO₂ are not interchangeable formulas. |
LTO | Lithium titanate, commonly written as lithium titanate oxide in battery terminology. The formula and electrode role should be stated because usage can vary between a material name and a complete cell description. |
m, k, M, n, and p | Common SI prefixes: milli-, kilo-, mega-, nano-, and pico-. Case matters: mHz is millihertz, while MHz is megahertz. |
For engineering units, ft is foot, g is gram, h is hour, kg is kilogram, km is kilometer, kN is kilonewton, kPa is kilopascal, kW is kilowatt, kWh is kilowatt-hour, and m is meter. A kilowatt is a power unit; a kilowatt-hour is an energy unit. A kilojoule is 1,000 joules, while a kilonewton is 1,000 newtons.
Battery Materials, Chemistries, Measurements, and Charging Terms from M Through P
| Term | Meaning and technical use |
|---|---|
mAh | Milliampere-hour, equal to one-thousandth of an ampere-hour. It is common for small cells and portable devices. |
MCFC | Molten carbonate fuel cell. It uses a molten carbonate electrolyte and operates at high temperature. |
mpg | Miles per gallon, a vehicle fuel-economy measure. It is not a direct battery-efficiency unit. |
Na-S | Sodium-sulfur battery. It is a high-temperature rechargeable battery chemistry using sodium and sulfur. |
NCA or LiNiCoAlO₂ | Lithium nickel cobalt aluminum oxide, a lithium-ion cathode family. |
NDV | Negative delta voltage. In some rechargeable-battery chargers, a small voltage decline near the end of charge can be used as part of charge termination. |
NG | Natural gas. |
NiCd | Nickel-cadmium rechargeable battery. Cadmium is a regulated hazardous substance in many applications and jurisdictions. |
NiFe | Nickel-iron rechargeable battery. |
NiH | Nickel-hydrogen battery, used especially in specialized energy-storage applications. |
NiMH | Nickel-metal hydride rechargeable battery. |
NiZn | Nickel-zinc rechargeable battery. |
NMC or LiNiMnCoO₂ | Lithium nickel manganese cobalt oxide, a lithium-ion cathode family. The relative metal composition can vary. |
NTC | Negative temperature coefficient. An NTC thermistor’s resistance decreases as temperature rises; it is commonly used for temperature sensing. |
OCV | Open-circuit voltage. It is measured without intended load current and should not be substituted for operating voltage. |
PAFC | Phosphoric acid fuel cell. |
PHEV | Plug-in hybrid electric vehicle. It combines a rechargeable traction battery with another propulsion system and can be charged from an external electrical supply. |
PTC | Positive temperature coefficient. A PTC device increases resistance as temperature rises and can provide resettable overcurrent or thermal protection. PTC can also describe a PTC thermistor or the protection component itself. |
pf | Picofarad, a unit of capacitance equal to one trillionth of a farad. Lowercase pf can also mean power factor in some documentation; the surrounding unit or formula resolves the ambiguity. |
PF | Power factor, the ratio describing how effectively alternating-current power is converted into useful real power. It is distinct from picofarad. |
NCV | Net calorific value, the heat released by combustion excluding the latent heat recovered by condensing generated water vapor. It is also called lower heating value in many energy contexts. |
Primary batteries are intended for one-way electrochemical discharge and are not designed for normal recharging. Secondary batteries are rechargeable. Fuel cells generate electricity while reactants are supplied, whereas capacitors store energy electrostatically or through electrochemical double-layer mechanisms. These categories should not be treated as interchangeable simply because all can deliver electrical power.
When reading a charging or protection specification, check the complete set of conditions: chemistry, cell count, voltage limit, current limit, temperature range, cutoff method, balancing strategy, and whether the value applies to a cell, module, or complete pack. Abbreviations such as CCCV, OCV, CCV, NTC, and PTC describe parts of that control system, but they do not by themselves define a safe charging procedure.
The same caution applies to battery test abbreviations. CCA, or cold-cranking amperes, is an automotive starting-battery performance rating. Its result depends on the applicable testing organization and procedure, including specified temperature, discharge duration, cutoff or pass voltage, battery condition, and rating convention. BCI, IEC, and DIN procedures should therefore not be compared as though their numerical results were automatically identical.
Finally, abbreviations should be expanded at first use when a document may be read outside its specialist group. This is especially important for FCC, CEC, PTC, pf, IS, and DCA, which can have multiple accepted meanings. A reliable battery specification defines the abbreviation, unit, test condition, and object being measured rather than relying on the letters alone.
References
- Abbreviations and Symbols » Academics | Boston University. (n.d.). https://www.bu.edu/academics/bulletin/abbreviations-and-symbols
- Subject Abbreviations | Winthrop University. (n.d.). https://www.winthrop.edu/recandreg/subject-abbreviations.aspx
- Abbreviations & Codes | Office of the University Registrar. (n.d.). https://www.bu.edu/reg/registration/abbreviations
- course abbreviations. (n.d.). https://www.scccd.edu/shared-documents/rtg/clovis-course-abbreviations.pdf
- Stony Brook Undergraduate Bulletin - Fall 2024Courses By Abbreviation. (n.d.). https://www.stonybrook.edu/sb/bulletin/current-fall24/courses/browse/byabbreviation
- Documentation - Standard Abbreviation Guide. (n.d.). https://stgenssa.sccgov.org/debs/program_handbooks/cwes/assets/34Doctn/05_34DocStdAbbrevGuide.htm
- APA Abbreviation Usage and Format. (n.d.). https://mym.cdn.usa.edu/WritingCenter/Abbreviation_Usage_and_Format_APA.pdf