Electric vehicles are the future, but if you’ve been driving gasoline-powered cars for decades, the parlance of this new technology can be head-spinning. What’s the difference between Level 1 and Level 2 charging? What makes a battery solid-state? How is MPGe calculated? This EV glossary will decode all the jargon you need to know to understand electric vehicles.
We’ve broken the guide up by subjects so you can see related terms grouped together.
Classification definitions
Internal combustion engine vehicle (ICEV): A traditional vehicle that relies on petroleum fuel to operate.
Electric vehicle (EV): A vehicle propelled by an electric motor. EV is a wide umbrella term that can encompass many different subtypes.
Battery electric vehicle (BEV): A vehicle that runs exclusively on battery power.
Hybrid (HEV): A vehicle that uses both an electric motor and an internal combustion engine to achieve better efficiency.
Plug-in hybrid vehicle (PHEV): A hybrid vehicle that includes a plug for charging its internal batteries, allowing it to run on electricity for longer than a conventional hybrid.
Extended range electric vehicle (EREV): A vehicle that relies primarily on electric power, but also has a combustion engine as a backup for when the charge dies. Unlike a hybrid, the engine never drives the wheels directly.
Mild hybrid electric vehicles (MHEV): A vehicle that relies primarily on an internal combustion engine, with support available from a small electric motor. MHEVs are unable to operate on battery power alone.
Zero-emission vehicle (ZEV): A vehicle that emits no pollutants from its operation.
Fuel cell electric vehicle (FCEV): A vehicle that relies on hydrogen fuel cells to charge the vehicle’s battery.
Worldwide harmonized light vehicles test procedure (WLTP): A modern test that measures the fuel consumption and emissions of vehicles in real-world driving.
New European driving cycle (NEDC): A now-retired test that measured the fuel consumption and emissions of vehicles. It was replaced in 2017 by the WLTP.
Neighborhood electric vehicle (NEV): A small, low-speed electric vehicle.
Part definitions
Internal combustion engine (ICE): The gas-powered heart of traditional cars. It generates power by compressing gas with a piston, then firing a spark plug to cause an explosion, which pushes the piston outwards. This in turn rotates the crankshaft, which moves through the transmission, which moves the driveshaft, which moves the axles, which moves the wheels, which moves your car.
Motor: The electrical heart of an EV. It converts electrical power into mechanical power by running a current through multiple circuits of wound copper wire shaped in a cylinder, which creates a rotating magnetic field. The rotation of the magnetic field moves a rotor housed within the cylinder. This rotor then rotates an axle and an EV’s wheels.
Transmission: A set of gears that adjust the final power sent to the driveshaft, axles, and wheels. Cars switch between these gears in order to change the delivery of power without changing how fast the engine is running.
Reducer: The EV equivalent to a transmission converts the high torque of an electric motor to more rotations per minute.
Drive unit: The combination of an EV motor and its reducer.
Battery: Where an electric vehicle’s power is stored. It’s the EV equivalent of a gas tank. Our guide to how batteries work explains more of the intricacies, and the history of how they came to be.
Battery cell: The smallest unit in an EV’s overall battery pack. Thousands of cells are often required to store enough electricity for an EV.
Battery module: A group of battery cells bundled together in an EV’s overall battery pack.
Battery pack: The total structure of an EV’s battery. It includes all modules and the cells that compose them, the enclosure, and structural features.
Lithium-ion: The battery technology used on most EVs (and most electronics like your phone, for that matter). They offer very high energy density and the ability to be recharged many times.
Solid-state battery: An emerging type of battery uses a solid electrolyte between the anode and cathode, rather than a liquid electrolyte. This allows solid-state batteries to be lighter, less explosive, and smaller. Several EV manufacturers have been pursuing solid-state batteries, but have yet to bring anything to market.
Battery management system (BMS): A system that ensures each cell is draining at roughly equal rates, and coordinates input and output so they all act is a single unit.
Battery heating system (BHS): A system that ensures the battery pack remains at ideal operating temperatures. This is necessary in cooler temperatures, which adversely affect battery life and charging speed.
On-board charger (OBC): On-board chargers convert alternating current to direct current in order to charge an EV’s batteries. Fast-charging stations don’t need to use an EV’s OBC since they are already direct current.
Inverter: An inverter converts a battery’s direct current into an alternating current.
Low voltage DC-DC converter (LDC): A component that reduces the voltage of an EV battery’s power so it can be used by supplementary systems within the car, like the headlights.
Vehicle control unit (VCU): The processing center of a vehicle, which coordinates power control, motor control, regenerative braking, power supply, and load management.
Electric power control unit (EPCU): The electric power control unit combines the inverter, low voltage DC-DC converter, and vehicle control unit into a single unit overseeing major responsibilities in an EV’s system management.
Range extender (REx): A small internal combustion engine used to recharge an EV’s batteries.
Frunk: Since EVs don’t have motors under the hood in the front, it’s used for storage space. It’s lovingly called the frunk, short for “front trunk”.
Electrical definitions
Amp (A): Amps (or amperes) are a measurement of electrical current. This measures how many electrons are passing through a point at a given time. One amp is equal to one coulomb (a unit of electrons) per second. Think of this as the water flow rate in your home plumbing. Amps are calculated by dividing power (wattage) by voltage.
Volts (V): A measurement of electrical force. It measures the amount of work needed to move an amp of energy between two points. Think of it like water pressure in your home plumbing. Voltage is calculated by dividing power (wattage) by current (amperage). You’ll often see voltage ratings for charging stations. A higher voltage means a higher charging rate for your EV.
Watts (W): A measurement of electrical power. One watt is equal to one joule (a unit of work) per second. Wattage is calculated by multiplying voltage by current (amperage). Since watts take into account the force and the flow rate of electricity, it is often the measure of the final electrical output for charging points.
Ohms (Ω): A measurement of electrical resistance. Resistance determines how well a material conducts electricity. One of the reasons EVs charge more slowly in cold climates is because lower temperatures increase electrical resistance. Battery degradation can also increase resistance. A given wire’s length, thickness, and material have a significant effect on resistance. Ohms are calculated by dividing voltage by current (amperage).
Kilowatt (kW): One thousand watts.
Kilowatt-hours (kWh): A measurement of the power of one kilowatt maintained for one hour. It is a common method for determining the total power potential of any given battery.
Amp-hours (Ah): A measurement of the total current a battery can emit over one hour. It is a common method of determining the total energy capacity of any given battery.
Watt-hours per kilogram (Wh/kg): A measurement of the energy density of a battery, relative to weight. This is especially helpful in EVs, as heavier batteries will slow down the vehicle.
Watt-hours per liter (Wh/L): A measurement of the energy density of a battery, relative to volume. With a high rating, a battery contains more energy proportional to its size.
Alternating current (AC): The electrical standard homes are built on. It allows long runs of cable with less power loss.
Direct current (DC): The electrical standard most modern electronics and EVs are built on. EVs typically need to convert AC power to DC in order to charge their batteries. Read more about direct current here.
Resistor: A module in an electrical circuit that slows current. This can be used to split voltage between different routes, match voltage to meet certain tolerance levels, or even generate heat.
Transistor: A module in an electrical circuit that modulates electrical power. This allows incoming electrical signals to be amplified, or switch from exiting onto one circuit from another.
Capacitor: A module in an electrical circuit that retains power. It doesn’t hold power for as long as a battery but is able to retain enough to accommodate temporary losses of power or to regulate spikes in power.
Supercapacitor: A much higher-capacity capacitor. Though it can retain more power than a lithium-ion battery and charge more quickly, it is less able to regulate output. Supercapacitors have been used in pilot projects with electric buses, so they can quickly charge at routine stops.
Anode: The side of the battery where electrons flow in.
Cathode: The side of the battery where electrons flow out.
Renewable energy: Electricity generated by perpetual natural sources. Solar, hydroelectric, and wind power are all examples of renewable energy, in contrast to natural gas and oil, which exist in limited amounts that will eventually run out.
Mechanical definitions
Torque: The twisting force that rotates the tires of a vehicle. EVs typically have significantly higher torque than traditional cars, because electric motors produce it instantly from a dead stop, rather than needing to build speed like combustion engines.
Horsepower (hp): A measurement of work being done. It is equal to the force in pounds multiplied by the distance in feet divided by time in minutes. It is a common means of measuring the power of a vehicle, though EVs often defer to kW.
Revolutions per minute (RPM): A measurement of how many times a shaft turns in a minute, particularly when transferring power from a motor to a crankshaft in a car. EVs enjoy much higher RPMs than internal combustion engines.
Regenerative braking: A way for EVs to transfer the slowing momentum of the vehicle into additional charging for your battery.
Range: How far an EV can drive on a single charge.
All-electric range (AER): How far a vehicle can drive on electric charge alone. This is often used when talking about hybrid vehicles, which use electric power alongside other sources.
Range per hour (RPH): A measurement of charging time. Though it’s possible to measure kW when charging, translating it into real performance will depend on vehicle design and weight. RPH takes those factors into account.
Range anxiety: A driver’s worry that there isn’t enough of a charge in an EV to complete their entire trip.
Miles per gallon equivalent (MPGe): A measurement of how far a vehicle can travel with 33.7 kWh, which is the equivalent energy found in one gallon of gas. This allows drivers to compare the efficiency of EVs and gas vehicles.
Miles per kilowatt-hour (mpkWh): A measurement of an EV’s efficiency. It demonstrates how an EV’s power output translates into real distance traveled. This is a key factor since design and weight play a large role in how efficiently battery power is used.
Drag coefficient (Cd): A measurement of a vehicle’s wind resistance. The higher the drag coefficient, the harder the motor has to work to push the vehicle through the air in front of it.
Infrastructure definitions
Electric vehicle supply equipment (EVSE): Everything you need to charge your EV. This includes cables, connectors, and charging points. Primarily, EVSE includes safeguards to ensure you aren’t overcharging and damaging your vehicle or endangering yourself.
Level 1 charging: The baseline charging level for EVs. It’s what’s available from a standard household outlet, providing a charge of up to 120V and between 8A and 20A. Level 1 charging typically takes a full 24 hours to top up an empty EV.
Level 2 charging: The charging level at most dedicated charging points. They charge EVs quite a bit more quickly with 240V output up to 80A. A full charge at a Level 2 point takes about 4 hours.
Level 3 charging: The fastest charging you’ll find. These charging points use direct current to charge EV batteries quickly, often in a half hour. Tesla has a network of superchargers that take advantage of unique connectors to deliver level 3 charging rates. Level 3 charging goes up to 900V at over 100A.
Connector: The physical end of the cable at a charging point, which goes into your car. There are multiple connector types compatible with certain cars.
Single phase charging: A connector that has a single cable for power draw.
Three-phase charging: A connector that has three cables for power draw. These are typically required to benefit from level 3 charging.
Type 1 plug: The most common EV connector charges up to 7kW. It is a five-pin, single-phase plug often used in the US. Also known as SAE-J1772, or a J plug.
Type 2 plug: A connector that charges up to 250kW. It is a seven-pin, triple-phase plug often used in Europe. It is sometimes called a Mennekes plug.
Combined charging system (CCS): Combined charging system is a kind of connector that charges up to 350kW. It includes DC charging pins often below a type 1 plug. Available in both Combo 1 and Combo 2 configurations for the US and Europe respectively. CCS is among the most common EV plugs.
CHAdeMO: A kind of connector that charges up to 100kW. It is a four-pin, direct current standard often used in Asia.
GB/T: A kind of connector that charges up to 250kW. It is a seven-pin standard primarily used in China.
ChaoJi: An upcoming connector that will charge up to 900kW. It will replace both GB/T and CHAdeMO while maintaining backward compatibility.
Open Charge Point Interface (OCPI): The Open Charge Point Interface allows for automatic roaming between a handful of charging networks. This means your EV can be charged on multiple different networks, and prices between them stay transparent. The OCPI is managed by the EVRoaming Foundation.
Open Charge Point Protocol (OCPP): The Open Charge Point Protocol is an open standard by which charging stations can communicate with their operators. It also allows information to flow between EVs and the electrical grid.
Open Smart Charging Protocol (OCSP): The Open Smart Charging Protocol allows for communication between charge points and energy management systems. This helps charging point operators and utility managers predict the local grid capacity.
Open Charge Alliance (OCA): The Open Charge Alliance maintains both OCPP and OSCP standards.
Off-peak charging: Charging your EV when electrical rates are at their lowest — typically at night.
Site owner: The site owner is the entity that owns the property where a charging point is installed.
Charge point operator (CPO): Charge point operators maintain a network of charging points, coordinate with site owners, manage installation and maintenance, and ensure operations with utilities go smoothly.
Charge point installer (CPI): Charge point installers sell and maintain charging points made by multiple manufacturers.
Electro-mobility service provider (eMSP): Electro-mobility service providers give EV drivers access to a bunch of charging points in specific areas. They relay billing, location, and availability information to end-users, while also plugging into a CPO’s larger network.
Roaming network operator (RNO): Roaming network operators connect regional eMSPs with larger CPO networks. This allows them to exchange charging data.
Electric vehicle service provider (EVSP): Electric vehicle service providers manage back-end software and communications for charging points.
Distribution network operator (DNO): Distribution network operators deliver electricity from national transmission networks to homes and businesses.
