4 Types of Electric Vehicles
Battery Electric Vehicle
A battery electric vehicle (BEV), pure electric vehicle, only-electric vehicle, fully electric vehicle or all-electric vehicle is a type of electric vehicle (EV) that exclusively uses chemical energy stored in rechargeable battery packs, with no secondary source of propulsion (a hydrogen fuel cell, internal combustion engine, etc.). BEVs use electric motors and motor controllers instead of internal combustion engines (ICEs) for propulsion. They derive all power from battery packs and thus have no internal combustion engine, fuel cell, or fuel tank. BEVs include – but are not limited to[1][2] – motorcycles, bicycles, scooters, skateboards, railcars, watercraft, forklifts, buses, trucks, and cars.
In 2016, there were 210 million electric bikes worldwide used daily.[3] Cumulative global sales of highway-capable light-duty pure electric car vehicles passed the one million unit milestone in September 2016.[4] As of October 2020, the world's top selling all-electric car in history is the Tesla Model 3, with an estimated 645,000 sales,[5] followed by the Nissan Leaf with over 500,000 sales as of September 2020.[6]
Hybrid Electric Vehicles
Today's hybrid electric vehicles (HEVs) are powered by an internal combustion engine in combination with one or more electric motors that use energy stored in batteries. HEVs combine the benefits of high fuel economy and low tailpipe emissions with the power and range of conventional vehicles.
A wide variety of HEV models are currently available. Although HEVs are often more expensive than similar conventional vehicles, some cost may be recovered through fuel savings or state incentives. Compare HEV and non-hybrid models side by side using the "Can a Hybrid Save Me Money?" tool on FuelEconomy.gov. The tool compares the costs of a selected HEV with a comparably equipped non-hybrid model from the same manufacturer and provides fuel cost savings associated with the HEV option.
Help from an Electric Motor
In an HEV, the extra power provided by the electric motor may allow for a smaller combustion engine. The battery can also power auxiliary loads and reduce engine idling when the vehicle is stopped. Together, these features result in better fuel economy without sacrificing performance.
Regenerative Braking
An HEV cannot plug in to off-board sources of electricity to charge the battery. Instead, the vehicle uses regenerative braking and the internal combustion engine to charge. The vehicle captures energy normally lost during braking by using the electric motor as a generator and storing the captured energy in the battery.
View an animation showing how HEVs work. Download Flash Player or view the text version.
Fuel-Efficient System Design
HEVs can be either mild or full hybrids, and full hybrids can be designed in series or parallel configurations.
Mild hybrids—also called micro hybrids—use a battery and electric motor to help power the vehicle and can allow the engine to shut off when the vehicle stops (such as at traffic lights or in stop-and-go traffic), further improving fuel economy. Mild hybrid systems cannot power the vehicle using electricity alone. These vehicles generally cost less than full hybrids but provide less fuel economy benefit than full hybrids.
Full hybrids have larger batteries and more powerful electric motors, which can power the vehicle for short distances and at low speeds. These vehicles cost more than mild hybrids but provide better fuel economy benefits.
There are different ways to combine the power from the electric motor and the engine. Parallel hybrids—the most common HEV design—connect the engine and the electric motor to the wheels through mechanical coupling. Both the electric motor and the internal combustion engine drive the wheels directly. Series hybrids, which use only the electric motor to drive the wheels, are more commonly found in plug-in hybrid electric vehicles.
Plug-In Hybrid Electric Vehicles
Plug-in hybrid electric vehicles (PHEVs) use batteries to power an electric motor, as well as another fuel, such as gasoline or diesel, to power an internal combustion engine or other propulsion source. PHEVs can charge their batteries through charging equipment and regenerative braking. Using electricity from the grid to run the vehicle some or all of the time reduces operating costs and fuel use, relative to conventional vehicles. PHEVs may also produce lower levels of emissions, depending on the electricity source and how often the vehicle is operated in all-electric mode.
There are several light-duty PHEVs commercially available, and medium-duty vehicles are now entering the market. Medium- and heavy-duty vehicles can also be converted to PHEVs. Although PHEVs are generally more expensive than similar conventional and hybrid vehicles, some cost can be recovered through fuel savings, a federal tax credit, or state incentives.
Powered by Electric Motor and Combustion Engine
PHEVs have an internal combustion engine and an electric motor, which uses energy stored in batteries. PHEVs generally have larger battery packs than hybrid electric vehicles. This makes it possible to drive moderate distances using just electricity (about 15 to 60-plus miles in current models), commonly referred to as the "electric range" of the vehicle.
During urban driving, most of a PHEV's power can come from stored electricity. For example, a light-duty PHEV driver might drive to and from work on all-electric power, plug the vehicle in to charge at night, and be ready for another all-electric commute the next day. The internal combustion engine powers the vehicle when the battery is mostly depleted, during rapid acceleration, or when intensive heating or air conditioning loads are present. Some heavy-duty PHEVs work the opposite way, with the internal combustion engine used for driving to and from a job site and electricity used to power the vehicle's auxiliary equipment or control the cab's climate while at the job site.
Fueling and Driving Options
PHEV batteries can be charged by an outside electric power source, by the internal combustion engine, or through regenerative braking. During braking, the electric motor acts as a generator, using the energy to charge the battery, thereby recapturing energy that would have been lost. Learn more about charging PHEVs.
PHEV fuel consumption depends on the distance driven between battery charges. For example, if the vehicle is never plugged in to charge, fuel economy will be about the same as a similarly sized hybrid electric vehicle. If the vehicle is driven a shorter distance than its all-electric range and plugged in to charge between trips, it may be possible to use only electric power. Therefore, consistently charging the vehicle is the best way to maximize the electric benefits.
Fuel-Efficient System Design
Beyond battery storage and motor power, there are various ways to combine the power from the electric motor and the engine. The two main configurations are parallel and series. Some PHEVs use transmissions that allow them to operate in either parallel or series configurations, switching between the two based on the drive profile.
Parallel hybrid operation connects the engine and the electric motor to the wheels through mechanical coupling. Both the electric motor and the engine can drive the wheels directly.
Series plug-in hybrids use only the electric motor to drive the wheels. The internal combustion engine is used to generate electricity for the motor. Vehicles of this type are often referred to as extended-range electric vehicles. The electric motor drives the wheels almost all of the time, but the vehicle can switch to work like a parallel hybrid at highway speeds when the battery is depleted
Fuel Cell Electric Vehicles
Fuel cell electric vehicles (FCEVs) are powered by hydrogen. They are more efficient than conventional internal combustion engine vehicles and produce no tailpipe emissions—they only emit water vapor and warm air. FCEVs and the hydrogen infrastructure to fuel them are in the early stages of implementation. The U.S. Department of Energy leads research efforts to make hydrogen-powered vehicles an affordable, environmentally friendly, and safe transportation option. Hydrogen is considered an alternative fuel under the Energy Policy Act of 1992 and qualifies for alternative fuel vehicle tax credits.
What is a fuel cell electric vehicle?
FCEVs use a propulsion system similar to that of electric vehicles, where energy stored as hydrogen is converted to electricity by the fuel cell. Unlike conventional internal combustion engine vehicles, these vehicles produce no harmful tailpipe emissions. Other benefits include increasing U.S. energy resiliency through diversity and strengthening the economy.
FCEVs are fueled with pure hydrogen gas stored in a tank on the vehicle. Similar to conventional internal combustion engine vehicles, they can fuel in less than 4 minutes and have a driving range over 300 miles. FCEVs are equipped with other advanced technologies to increase efficiency, such as regenerative braking systems that capture the energy lost during braking and store it in a battery. Major automobile manufacturers are offering a limited but growing number of production FCEVs to the public in certain markets, in sync with what the developing infrastructure can support.
How Fuel Cells Work
The most common type of fuel cell for vehicle applications is the polymer electrolyte membrane (PEM) fuel cell. In a PEM fuel cell, an electrolyte membrane is sandwiched between a positive electrode (cathode) and a negative electrode (anode). Hydrogen is introduced to the anode, and oxygen (from air) is introduced to the cathode. The hydrogen molecules break apart into protons and electrons due to an electrochemical reaction in the fuel cell catalyst. Protons then travel through the membrane to the cathode.
The electrons are forced to travel through an external circuit to perform work (providing power to the electric car) then recombine with the protons on the cathode side where the protons, electrons, and oxygen molecules combine to form water. See the Fuel Cell Electric Vehicle (FCEV) infographic to learn more about the process.
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