ELECTRIC VEHICLES (EVs)
EVs are vehicles powered by electricity and an electric motor rather than a conventional gasoline-fueled internal-combustion engine.
All-electric vehicles, also referred to as battery electric vehicles (BEVs), have an electric motor instead of an internal combustion engine. The vehicle uses a large traction battery pack to power the electric motor and must be plugged in to a wall outlet or charging equipment, also called electric vehicle supply equipment (EVSE). Because it runs on electricity, the vehicle emits no exhaust from a tailpipe and does not contain the typical liquid fuel components, such as a fuel pump, fuel line, or fuel tank.
Electric cars function by plugging into a charge point and taking electricity from the grid. They store the electricity in rechargeable batteries that power an electric motor, which turns the wheels. Electric cars accelerate faster than vehicles with traditional fuel engines – so they feel lighter to drive.
Key Components of an All-Electric Car
Battery (all-electric auxiliary): In an electric drive vehicle, the auxiliary battery provides electricity to power vehicle accessories.
Charge port: The charge port allows the vehicle to connect to an external power supply in order to charge the traction battery pack.
DC/DC converter: This device converts higher-voltage DC power from the traction battery pack to the lower-voltage DC power needed to run vehicle accessories and recharge the auxiliary battery.
Electric traction motor: Using power from the traction battery pack, this motor drives the vehicle's wheels. Some vehicles use motor generators that perform both the drive and regeneration functions.
Onboard charger: Takes the incoming AC electricity supplied via the charge port and converts it to DC power for charging the traction battery. It also communicates with the charging equipment and monitors battery characteristics such as voltage, current, temperature, and state of charge while charging the pack.
Power electronics controller: This unit manages the flow of electrical energy delivered by the traction battery, controlling the speed of the electric traction motor and the torque it produces.
Thermal system (cooling): This system maintains a proper operating temperature range of the engine, electric motor, power electronics, and other components.
Traction battery pack: Stores electricity for use by the electric traction motor.
Transmission (electric): The transmission transfers mechanical power from the electric traction motor to drive the wheels.
afdc.energy How-do-all-electric-cars-work
EVs and their range
How far you can travel on a full charge depends on the vehicle. Each model has a different range, battery size and efficiency. The perfect electric car for you will be the one you can use for your normal journeys without having to stop and charge up halfway through.
IN THIS ARTICLE
What types of electric cars are there?
What types of electric cars are there?
There are a few different types of electric vehicle (EV). Some run purely on electricity, these are called pure electric vehicles. And some can also be run on petrol or diesel, these are called hybrid electric vehicles.
There are several types of EVs, all powered a little differently:
- Battery electric vehicles (BEVs)are powered by rechargeable electric batteries. BEVs produce no tailpipe emissions and have no combustion engine.
- Plug-in hybrid electric vehicles (PHEVs) are powered by an electric motor as well as a small combustion engine. They have an all-electric range from 20 to 60 miles and can be charged at a charging station.
- Hybrid electric vehicles (HEVs) have an internal-combustion engine and an electric motor that assists only at low speeds. The battery is charged either by the combustion engine or through recuperation when braking.
- Fuel cell electric vehicles (FCEVs) use electric motors. The electricity is generated in fuel cells and can be stored in a small buffer battery. Fuel cell vehicles require hydrogen (compressed into tanks) as fuel.
- Plug-in electric - This means the car runs purely on electricity and gets all its power when it's plugged in to charge. This type doesn't need petrol or diesel to run so doesn't produce any emissions like traditional cars.
- Plug-in hybrid - These cars mainly run on electricity but also have a traditional fuel engine so you can use petrol or diesel too if they run out of charge. When running on fuel, these cars will produce emissions but when they're running on electricity, they won't. Plug-in hybrids can be plugged into an electricity source to recharge their battery.
- Hybrid-electric - These run mainly on fuel like petrol or diesel but also have an electric battery too, which is recharged through regenerative braking. These let you switch between using your fuel engine and using 'EV' mode at the touch of a button. These cars cannot be plugged into an electricity source and rely on petrol or diesel for energy.
What are the inner parts of an EV?
EVs have 90% fewer moving parts than an ICE (Internal Combustion Engine) car. Here's a breakdown of the parts that keep an EV moving:
- Electric Engine/Motor - Provides power to rotate the wheels. It can be DC/AC type, however, AC motors are more common.
- Inverter - Converts the electric current in the form of Direct Current (DC) into Alternating Current (AC)
- Drivetrain - Most EVs have a single-speed transmission which sends power from the motor to the wheels.
- Batteries - Store the electricity required to run an EV. The higher the kW of the battery, the higher the range.
- Charging - Plug into an outlet or EV charging point to charge your battery.
EV batteries - capacity and kWh explained
Kilowatts (kW) is a unit of power (how much energy a device needs to work). A kilowatt-hour(kWh) is a unit of energy (it shows how much energy has been used), e.g. a 100 watt lightbulb uses 0.1 kilowatts each hour. An average home consumes 3,100 kWh of energy a year. An electric car consumes an average of 2,000 kWh of energy a year.
Are there other EVs aside from cars?
The popularity of electric bikes and scooters, driven by their affordability and ease of access, represents a new chapter in micromobility.
On the opposite end of the EV spectrum are e-trucks. Demand for them is booming in response to a regulatory push to reduce emissions in the logistics and transport sectors. EU regulations now require new trucks to reduce carbon emissions 30 percent by 2030. California’s recent Advanced Clean Truck regulation requires manufacturers of commercial vehicles to start selling e-trucks in 2024 and restricts all sales of new trucks to electric models by 2045.
Toward the end of this decade, we expect that fuel cell electric trucks, powered by hydrogen, will also penetrate the commercial-vehicle industry, especially in heavy-duty applications and long-haul use cases, where pure battery electric powertrains might have limitations given battery size and weight.
And in the broader world of mobility, electric aircraft are also on the horizon. Electric vertical takeoff and landing (eVTOL) aircraft could be flying above cities as soon as 2030. The global electric-aircraft market is estimated to reach $17.8 billion by the year 2028, according to a recent report. Funding for advanced air mobility, including electric aircraft, exceeded $8 billion as of March 2021.
What is the range of EVs?
Range is how far an EV can go before recharging, an important consideration for customers in the market for EVs. That’s because, at present, most EVs can travel only around half the distance of the typical ICE vehicle before recharging—and because charging stations are still few and far between, even in markets that have embraced EVs.
What is fast charging for EVs?
There are two types of chargers:
- Alternating current (AC) slow charging (3–22 kW) provides energy for, on average, 30 miles for an hour of charging. These are found in private homes and in public charging stations. AC is also used in private homes and can be installed easily.
- Direct-current (DC) fast charging (50–300 kW) provides, on average, at least 150 miles for 20 minutes of charging. This type of charging is available only at public charging stations and requires a significant investment to install.
Fast chargers are a considerable expense—as of 2022, the hardware alone for a 300-kW charger costs from $50,000 to $100,000, and installation can be just as pricey. The costs could drop by about 40 percent over the next five to seven years as demand for fast charging increases to reflect the expanding EV customer base. The greatest opportunity in the EV-charging value chain will come from on-the-go charging, which allows drivers to pay a premium to charge within an hour.
Governments, utilities, and charging companies need to consider several questions as they build out the charging infrastructure. For instance, where should charging stations be located—bearing in mind accessibility, convenience, and equity? What charging speed is essential? And what’s the best way to balance profitability and convenience?
How Do Electric Cars Work?
Electric cars are powered by storing energy from the electrical grid in batteries, then using that energy to drive electric motors that make the car go. Electric vehicles use energy stored in batteries to power electric motors. They make use of the relationship between electricity and magnetism: When an electric current flows through a wire, it creates a magnetic field, and vice versa. An electric motor works by running current through a coil of wire to spin magnets, and a generator — like the alternator in a traditional car — generates electricity by spinning magnets inside a coil. This is why EVs can recapture energy to charge their batteries.
Of course, the motors can't generate enough electricity to completely recharge the system, so electric cars need to be charged up by another method. This means plugging them in and charging the batteries with energy from the electrical grid.
Comparison with conventional fuel-powered vehicles
An internal combustion engine, or ICE, burns some type of combustible fuel (usually gasoline, but diesel, ethanol and other fuels are used, too) to generate the energy needed to move a vehicle. Beyond the whole "intentional fire" thing, there are some very important differences between using combustion and electricity for power.
- Gasoline, the most common ICE fuel, has a much higher energy density than current EV batteries. That means a battery pack needs to be much larger and heavier than a gas tank to provide an equivalent amount of energy. But ...
- Internal combustion engines are far less efficient than electric motors. The majority of the energy they generate burning fuel is lost as waste heat. In fact, only about a quarter of the energy stored in the gasoline winds up being used to move the vehicle. Electric cars, by comparison, are about 90% efficient.
- An internal combustion engine can't recapture energy — you can't un-burn gas. But electric motors can also act as generators, meaning that they can add energy back into the batteries while slowing down the vehicle. That's part of what makes them so efficient. It's also why hybrid cars offer big efficiency gains since they can recapture some of the energy the gas engine produces as electricity.
Components of an electric car motor
Electric motors are relatively simple mechanically since they don't require multiple moving parts. When current passes through a wire, it creates a magnetic field that exerts a force. If you've ever played with magnets, you know that the like poles repel each other while opposite poles attract each other. If you were to put a magnet inside an electric field, it would align itself with the field and then stop moving when it reached equilibrium. But if you keep the field switching back and forth, you can keep the magnet rotating by preventing it from ever reaching equilibrium. Switch the field faster than the magnet is spinning, and it'll spin faster to catch up, giving you acceleration.
In practice, electric motors are a bit more complex than that explanation suggests, but both direct current (DC) and alternating current (AC) motors use the same trick of rapidly switching the polarity of an electromagnetic field to generate motion.
So the opportunities for direct mechanical wear in electric motors are limited, and there's no combustion and no exhaust gases. It also means the power an electric motor can exert is determined by the strength of the magnetic field (which is determined by the amplitude of the current), not its rotational speed. Gasoline engines, conversely, need to expend energy to get themselves up to a minimum rotational speed before they can generate full power.
Because of the way electric motors operate, there are certain advantages to using an alternating current motor. AC motors can produce more power and operate more consistently when exposed to vibrations and other adverse conditions common when driving. They're also lighter, but they're more costly to produce.
Batteries
By far the most common type of battery currently used in electric cars is lithium ion (Li-ion). Lithium-ion batteries use an alloy of lithium and other metals in a liquid or polymer electrolyte solution to store charge.
Some older EVs used nickel-metal hydride (NiMH) batteries, but these batteries, while inexpensive to make, are heavier, less capable of discharging energy quickly, and more prone to damage from overcharging and to losing charge capacity.
In an electric car, lithium-ion batteries have lots of advantages. Saving weight is one, and easier, faster charging is another. Being able to discharge energy more quickly also means they can provide stronger acceleration.
Currently, a number of manufacturers and researchers are working on solid-state batteries, which still use lithium but don't require a liquid electrolyte solution. They promise significant weight savings, better energy density, faster charging, and less risk of fire due to damage. Nissan has committed to the fastest timeline, promising solid-state batteries in 2028.
Kilowatt-hours
Battery capacity is measured in kilowatt-hours, or kWh. This is very different from the way gasoline is measured, in gallons, because it doesn't have anything to do with weight or volume, but with how much actual energy is available. Usually, kWh is used as a measure of work. You see it most commonly on your utility bill, where it indicates how much power you used.
For example, a 300-watt space heater would need to run for just over three hours to use 1 kWh, while a 60-watt lightbulb would need to run for more than 16 hours. The average American household uses about 30 kWh a day.
The efficiency of electric cars is best measured as the number of kWh it takes to travel 100 miles, or kWh/100 miles. Just like on a gas car, more "fuel" doesn't always mean more range; efficiency plays a major role as well.
It's important to note that charging speeds use kilowatts, not kWh. A watt measures the rate at which energy flows; a kWh is a way to measure how much energy has flowed.
Voltage: 400 volts vs. 800 volts
Different electric car platforms are capable of handling different voltages. By increasing the voltage, you can increase the power (wattage) without increasing the amount of current (amperage). This means less heat, less need for cooling, lighter-weight components and more efficiency. One of the most important advantages of EVs with 800-volt architecture is faster charging … assuming you can find a powerful enough charging station.
For the most part you'll see 400-volt or 800-volt cars, although there are a few outliers. The Lucid Air uses suspiciously specific 924-volt architecture. Some vehicles, like the Hummer EV, use 400 volts for driving and 800 volts for charging. Some have variable limits, like the Porsche Taycan, which can temporarily charge at up to 1,000 volts.
Ultimately, the higher voltage systems offer weight savings and improved performance but come with a higher price tag.
Power inverter
Batteries require direct current (DC) to charge, and they release stored energy as direct current. But the power that comes from your wall socket for Level 1 or Level 2 charging is alternating current (AC). The motors in electric cars run on alternating current (and recapture energy as alternating current) since alternating current lets them provide more torque and more consistent operation regardless of conditions.
Power inverters convert DC to AC and vice versa — although they do much more than that. That means they're a necessary component for driving your electric car and for charging it at home. They convert energy coming from the battery to a form that's usable by the electric motors, and they convert energy recaptured by the motors, or energy coming from a Level 1 or Level 2 charging station, into a form that's usable by the battery.
Inverters are also capable of adjusting the frequency and amplitude of their output, which allows them to control the power and speed of an electric car's motors. Alternating current comes in pulses, and when the inverter converts DC to AC it can control the frequency and amplitude (think, strength) of the pulses it outputs. Increasing or decreasing the frequency of the pulses increases or decreases the speed at which the motor turns, and increasing or decreasing the amplitude of the pulses increases or decreases the torque the motor generates.
Benefits and limitations of power inverters in electric cars
Power inverters allow electric cars to charge from a household outlet or Level 2 charging station. They increase the range and efficiency of electric cars by allowing for the use of AC motors and allowing the motors to charge the battery.
Power inverters also add weight and cost to electric cars, and they are another potential point of failure should anything go wrong. They're also a major chokepoint in the system: Because all current flowing between the charger, motors and battery must go through the inverter, the limits of the inverter are also the limits of the car's performance for both acceleration and charge time. That's why Level 3 fast-charging stations provide direct current, bypassing the inverter and allowing much faster charge times.
Charging port
The charging port is where the plug from a charging station can be connected to an EV. What type of port you have will determine what kind of charging station you can connect to or what kind of adapter you'll need to charge.
In the United States, you're only likely to come across three types of charging ports on an electric vehicle: CCS, Tesla and CHAdeMO. CHAdeMO only appears in the U.S. on the Nissan Leaf, and it's headed the way of the dodo (at least in this country), so we won't spend time on it. Tesla, unsurprisingly, is used by all Tesla models. It's a single plug that can handle Level 1, 2 and 3 charging, which certainly makes life easy.
All other EVs being sold in the U.S. have CCS, or combined charging system, ports. This combines a Level 1 and 2 charging port, poetically named the SAE J1772 connector, with two high-speed charging pins (hence "combined"). Basically, if you're charging at home, you'll just plug in to part of your port. If you're using a public fast charger, you'll have a chunkier plug that connects to both parts of the combined port.
While CCS charging stations are currently capable of charging at a speed of 350 kW, your car may not be capable of accepting charge that quickly. With a little research, you can find out how fast your vehicle can charge when plugged into an appropriate DC fast charger.
Controller
The controller is the name for the electronics package that connects the batteries and motor or motors. When you step on the gas, apply the brakes, or switch into reverse, it's the controller that feeds current to the motor for acceleration, reverses the flow for regeneration, and even reverses the motor's direction of spin so you can back up. When using AC motors, the controller includes the car's inverter.
Charging an electric car
Types of charging stations
There are only three types of charging stations, but in practice, things aren't really that straightforward. The three types are
i. Level 1 (110-120 volt),
ii. Level 2 (220-240 volt) and
iii. Level 3, or DC fast charging.
That last one is where things get tricky, as fast-charging stations can technically have a voltage cap of anywhere between 480 volts and 1,000 volts, meaning a DC fast charger may be capable of delivering up to 360 kW of power, but some Level 3 stations may only deliver a peak of 50 kW.
If your EV can accommodate very fast charging, you'll need to make sure you find a Level 3 fast charger that's actually outputting enough power to take advantage. Many charging networks will let you check speed ranges of charging stations through their apps, but many will also charge extra for high-speed charging.
Tesla remains an outlier. While Teslas can use Level 1 and 2 chargers, they use Tesla Superchargers for fast charging. These charging stations operate at 480 volts but provide different amounts of power depending on the version. Version 1 and 2 Superchargers provide 150 kW, while version 3 provides up to 250 kW. Tesla claims a forthcoming version 4 will increase charging speed even more.
Home charging options
Home charging is generally done with a Level 2 charging station, a special piece of equipment that should be installed by an electrician. Level 2 charging stations require a 240-volt circuit, so if your home already has special plugs for an electric dryer, heater or water heater, you shouldn't have any issues. If your house doesn't have any 240-volt outlets, you'll need to consult an electrician to see if one can be installed.
Level 2 charging stations can be installed indoors or outdoors, so whether you park in a garage or in a driveway or carport, you should still be able to charge your EV. While not remotely as fast as a public DC fast charger, a Level 2 charging station should be able to refill the battery on most electric cars if left plugged in overnight.
It is possible to use a Level 1 charger, which only requires a standard 120-volt outlet. Many EVs come with adapters that let them plug in to a typical outlet to charge. Just be aware that charging speeds are painfully slow with a Level 1 charger — even if you plug in overnight you may not add more than 30 miles of range.
Public charging options
When charging in public, you'll usually find Level 2 charging stations and Level 3 DC fast chargers. While there are a handful of CHAdeMO stations, most public fast chargers will use CCS. If you own a Tesla, you'll have access to the Tesla Supercharger network. Tesla has also recently opened its charging stations to other EVs.
You may live somewhere with access to free or municipal charging stations, which will almost always be slower Level 2 stations. But for the most part you'll be charging at public stations owned and operated by a charging network. These stations allow you to pay as you go, but you can also sign up directly with one or several networks to make paying easier and maybe even save a bit of money on charging.
Remember, if you want to take full advantage of your car's max charging speed, you'll need to find a public DC fast-charging station with an output that matches or exceeds your car's spec.
Charging time
If you're charging with a Level 1 charger, you can expect to add 3-5 miles of range per hour, and with a Level 2 charger you can expect to add 25-30 miles of range per hour. These speeds are pretty consistent because the wattage of these charging stations and the capacity of the car's onboard power inverter are predictable.
For Level 3 fast charging, things are a bit more complicated. Most manufacturers will advertise a predicted maximum charging speed, usually from zero to 80% of max charge. These predictions are based on a Level 3 charging station with sufficient power output operating in ideal conditions, and you may not match them in real life.
Theoretically, you should be able to calculate your total charge time based on just the power output of the charging station and the total battery capacity of your vehicle.
When you first plug in, there's a conditioning time required before your battery can accept max charge speed. Max charge speed also only generally occurs for a brief period of time, which can vary depending on conditions and charge level. Charging speed also decreases as the battery passes 80% of maximum charge. Moreover, even a charger that claims a specific power output may not always operate at that output, and you won't know until you're plugged in. Level 3 charging time, in short, is relatively unpredictable.
Advantages and disadvantages of electric cars
Environmental benefits
Electric cars can bring significant benefits to local air quality if adopted at scale, and they also significantly reduce greenhouse gas emissions compared to gasoline-powered vehicles. The former may seem obvious, as EVs have no tailpipe emissions and produce no particulate or gaseous exhaust. That means fewer pollutants that have been linked to cancer, respiratory and cardiac issues, developmental delays, cognitive impairment and a plethora of other health concerns.
The latter — greenhouse-gas reduction compared to gasoline vehicles — is more nuanced. Local pollution from mining the materials needed to produce batteries is an issue, especially in countries with lax regulations. It's worth noting that these materials are in high demand even without considering the electric vehicle market, but as EV production scales up, this concern will only intensify.
It's also true that EV production creates more greenhouse gases than ICE vehicle production, in particular from battery manufacturing. EVs can potentially create up to 80% more carbon emissions during production, but once the vehicles hit the road it takes an average of about 15,000 miles for an ICE vehicle to surpass an EV in net emissions. The U.S. Department of Energy performed a study in 2022 and found that, on average, an EV in the United States creates 3,932 pounds of carbon dioxide equivalent per year. Gasoline vehicles, by comparison, create 11,435 pounds per year. Even when using electricity derived from coal plants, an EV creates fewer net carbon emissions because it uses energy so much more efficiently than a gasoline vehicle. Of course, electric cars can be charged using clean energy like solar, wind, hydro and geothermal power, meaning they can run as cleanly as the grid that charges them. That's an advantage an ICE vehicle can never have.
Cost comparison between charging an electric car and refueling a conventional vehicle
Gas and electricity prices both fluctuate, and DC fast chargers can have higher charging costs, especially during peak use hours. But the cost per mile of fueling an EV will almost always be less than the cost per mile of fueling an ICE vehicle. This is especially true if you can charge at home, as residential electricity rates are significantly lower than what you'll pay to use a public charging station.
If you live somewhere with access to very inexpensive gas and access to DC fast-charging stations, there may be some times where the cost to fuel per mile is greater using the Level 3 charger than it would be to buy gas. But while gas stays the same price all day, charging gets less expensive off peak hours, so you can save a bit by planning ahead of time when you'll charge up.
Ultimately, EV owners will save money compared to ICE vehicle owners when it comes to fuel
EV maintenance benefits
Electric cars are significantly less mechanically complex than ICE vehicles, although to varying degrees. Some EVs use simple transmissions, and most have other moving parts connecting the motors to the wheels. But the engines and transmissions of gasoline cars have thousands of moving parts, each of which can be a failure point, and as a result these cars require significantly more maintenance and upkeep to stay in good working order.
Electric motors also don't use oil the same way an ICE does, as you have probably surmised. Electric motors have bearings that may be greased, but grease doesn't degrade or require replacing like oil in a gasoline engine. Engine oil loses its lubricating ability relatively quickly, getting loaded up with contaminants even when an engine is operating perfectly. That's why oil filters need to be regularly replaced with engine oil.
Furthermore, with an electric car there are no timing belts/chains to replace, no spark plugs, no rings that can degrade or slip, no intake ports to clean, no exhaust pipes or mufflers to rust or perforate, no catalytic converters … the list goes on.
Indeed, the primary maintenance needs of electric cars are simply brakes and tires. Tires, in particular, can wear out faster on electric cars due to the extra weight of many EVs and their ability to apply immediate big torque on acceleration. Brakes, however, may last longer on EVs if regenerative braking is used heavily.
Battery packs do degrade over time, losing charge capacity, and they may eventually fail. But in most cases, this degradation shouldn't impact day-to-day driving for quite some time. Battery warranties are also commonly 100,000 miles and 10 years or more, generally longer than the warranties for gasoline engines.
If a battery pack does need replacing outside of warranty, the cost can range massively, from about $4,000 up to $20,000. Considering an average cost between the two extremes, and the savings on regular maintenance and repairs, an electric vehicle still costs less to maintain over its lifetime than a comparable gas vehicle.
Driving experience
Depending on how an electric vehicle is set up, it can feel more or less like a traditional ICE vehicle. The most noticeable difference when you get into an electric car will be the lack of noise and vibration from the powertrain. In fact, EVs are so quiet that they're legally required to have speakers that make an artificial noise at low speed so pedestrians have a chance to hear them coming.
Another key difference is the lack of gear changes. Electric motors can spin much more quickly than a gasoline engine, and they produce more consistent power regardless of the speed at which they're spinning. Electric motors also produce torque instantaneously from a stop, where a gasoline engine needs to rev up a bit to reach its peak torque output. The immediate torque and lack of shifts make for smoother driving and a feeling of instant acceleration.
The other major difference is regenerative braking. Most electric cars let you select how much or how little regenerative braking you'd like when you lift off the accelerator pedal. So if you'd prefer a more traditional feel, you can turn regenerative braking down so the vehicle will coast and only slow when you apply the brakes (when it will use a combination of regenerative and physical braking). But for the full EV experience, you can turn regenerative braking all the way up, which means the throttle becomes less an accelerator pedal and more a speed selector pedal.
This is called one-pedal driving, and it's not possible in every EV. Not all EVs have strong enough regenerative braking, and not all will be able to bring the vehicle to a full stop with regenerative braking. But in a vehicle where it's possible, the instant you lift off the pedal, the car will slow in accordance with how much you've lifted. So you use the pedal to select a constant speed, reducing pressure to maintain a slower speed and pushing down to maintain a higher speed — as opposed to a gas-powered car, where you would hold the pedal down to accelerate and then reduce pressure to maintain the speed you've reached.
Range limitations
Many people cite range anxiety as either a major concern in choosing an EV or a reason not to buy an EV at all. There are several reasons range anxiety is such a big problem for electric cars.
Gasoline cars are very flexible. Increasing or decreasing the size of the fuel tank to increase or decrease range doesn't have a large impact on vehicle weight or cost, and doesn't change how long it takes to refill by very much. Also, filling up even a large tank with gas only takes a few minutes.
In an EV, only so much can be done with aerodynamics and efficiency to add range; beyond that, the only solution is to add more battery cells. Not only is that a significant added cost, extra batteries also need a lot more space, and they add a lot of extra weight (which in turn hurts the vehicle's efficiency).
More batteries also mean more charging time, which is less of a problem if you have easy access to DC fast chargers, but that access is inconsistent nationally. Right now, the fastest-charging EVs can add a maximum of 15-20 miles per minute, significantly slower than refilling a gasoline car. And if you can't find a fast charger, or don't have a car capable of such high-speed charging, you might be stuck at a charger for a while to recharge enough to reach your destination.
Until there's more charging infrastructure, or new battery technology that can improve range and charge times, EVs will have limited appeal for people who need to drive long distances or who live in areas with few public charging options.
Charging infrastructure
Charging infrastructure is one of the biggest hurdles for EV adoption. At issue is both the number of charging stations available and their reliability. In our own extensive real-world testing of electric cars, we've experienced plenty of issues with charging stations operating at lower speeds than advertised, or not working at all. And with limited numbers, there can sometimes be wait times for charging stations in high-traffic areas. However, the number of charging stations is growing rapidly, and the bipartisan infrastructure law has allocated funds to build an additional 500,000 charging stations.
But if you have, or can install, a charging station where you live, infrastructure becomes much less of an issue for day-to-day life. If you can plug in at night and your commute doesn't involve significant distances every day, you'll basically wake up every morning with enough range to get through your day and get home again. As commuter cars, EVs have a massive edge over ICE vehicles in terms of convenience.
Will Kaufman Edmunds.com How-do-electric-cars-work
Electric car charging
How to charge an EV?
You can charge an electric vehicle either by plugging it into a socket or by plugging into a charging unit. There are plenty of charging stations around the UK to stay fully charged while you're out and about. There are three types of chargers:
Three-pin plug - a standard three-pin plug that you can connect to any 13 amp socket.
Socketed - a charge point where you can connect either a Type 1 or Type 2 cable.
Tethered - a charge point with a cable attached with either a Type 1 or Type 2 connector.
How long does it take to charge an electric car?
There are also three EV charging speeds:
- Slow - typically rated up to 3kW. Often used to charge overnight or at the workplace. Charging time: 8-10 hours.
- Fast - typically rated at either 7Kw or 22kW. Tend to be installed in car parks, supermarkets, leisure centres and houses with off-street parking. Charging time: 3-4 hours.
- Rapid - typically rated from 43 kW. Only compatible with EVs that have rapid charging capability. Charging time: 30-60 minutes.
Charging up in changing seasons
The weather affects how much energy your electric car consumes. You have a larger range in summer and smaller range in winter.
How far can you travel on one full charge?
An EVs range is dependent on the battery size (kWh). The higher the EV battery kWh, more power, the further you travel.
Edfenergy How-do-electric-cars-work
All types of electric-vehicle motors share two major parts. The stator is the motor's stationary outer shell, whose housing is mounted to the chassis like an engine block. The rotor is the lone rotating element and is analogous to a crankshaft in that it feeds torque out through the transmission and onto a differential.
Most EVs rely on a direct-drive (single-ratio) unit to step down the rotating speed between the motor and the wheels. Like internal-combustion engines, electric motors are most efficient at low rpm and higher load. While an electric car might enjoy an acceptable driving range with a single gear, heavier pickups and SUVs designed to pull trailers will increase range with a multi-speed transmission at highway speed. Today only the Audi e-tron GT and Porsche Taycan use a two-speed transmission. Multi-gear (spin) losses and development costs are reasons why EVs with more than one gear are uncommon, but we predict that will change.
EV Motor Commonality
All three major EV motor types use three-phase alternating current to set up a rotating magnetic field (RMF), the frequency and power of which are controlled by the power electronics that respond to the accelerator. Stators contain numerous parallel slots stuffed with interconnected loops of copper windings. These can be bulky looms of round copper wire or tidy hairpin-shaped copper insertions with square cross-sections that increase both fill density and direct wire-to-wire contact within the grooves. Denser windings improve torque capability, and tidier interlacing at the ends amounts to less bulk and a smaller overall package.
Batteries are direct-current (DC) devices, so an EV's power electronics include a DC-AC inverter to provide the stator with the AC current necessary to create the all-important variable RMF. But it's worth pointing out that these electric motors are also generators, which means that wheels will back-drive the rotor within the stator to induce an RMF in the other direction that feeds power back through the now AC-DC converter to send power into the battery. This process, known as regenerative braking, creates drag that slows the vehicle. Regen is not only central to extending an electric car's range, it's pretty much the whole ball of wax when it comes to highly efficient hybrids because lots of regen improves the EPA fuel-economy numbers. But in the real world, regen is less efficient than coasting, which avoids the losses each time the energy passes through the motor and converter when harvesting kinetic energy.
The Three EV Motor Types
The motor types can be broken down by fundamental rotor differences that represent entirely different ways of turning the stator's RMF into actual rotary motion. These differences are stark enough, in fact, that they do justice to our original four-cycle, two-cycle, and Wankel analogy. In the asynchronous category, we have induction motors, while the synchronous group contains permanent-magnet and current-excited motors.
Induction motors have been around since the 19th century. Here the rotor contains longitudinal laminations or bars of conductive material, most often copper but sometimes aluminum. The stator's RMF induces a current in these laminations, which in turn creates an electromagnetic field (EMF) that begins to rotate within the stator's RMF. Induction motors are known as asynchronous motors because the induced EMF and the rotating torque that comes with it can exist only when the rotor's speed lags behind the RMF. Such motors are common because they have no need for rare-earth magnets and are relatively cheap to manufacture, but they can be harder to cool at sustained high loads and are inherently less efficient at low speeds.
As the name implies, the rotors in permanent-magnet motors possess their own magnetism. No power is needed to create the rotor's magnetic field, making them far more efficient at low speed. Such rotors also turn in lock-step with the stator's RMF, making them synchronous. But there are problems with simply wrapping a rotor with surface-mounted magnets. This requires larger magnets, for one, and keeping a rotor together at high speed becomes more difficult as things get heavier. But the bigger problem is the so-called "back EMF" at high speeds, in which a reverse-induced electromagnetic magnetic field adds drag that limits top-end power and creates excess heat that can damage the magnets.
To combat this, most EV permanent-magnet motors feature internally mounted permanent magnets (IPM) that are slid in pairs into lengthwise V-shaped slots arrayed in multiple lobes just under the surface of the rotor's iron core. The slots keep the IPMs secure at high speed, but the deliberately shaped areas between the magnets create a reluctance torque. Magnets are either attracted to or repelled by other magnets, but ordinary reluctance, the force that sticks a magnet to a toolbox, attracts the lobes of the iron rotor to the RMF. IPMs do the work at lower speeds, and the reluctance torque takes over at high speeds. Lest you think this is new, the Prius uses them.
The final type of motor didn't exist in EVs until recently because conventional wisdom held that brushless motors, which describes the motors above, were the only viable option for an electric vehicle. BMW recently bucked this trend by fitting brushed current-excited AC synchronous motors to the new i4 and iX. This type's rotor interacts with the stator's RMF exactly the same as a permanent-magnet rotor, but the rotor lacks permanent magnets. Instead, it features six broad copper lobes energized with DC battery power to create the necessary EMF. Pulling this off takes slip rings and spring-loaded brushes on the rotor shaft, which has led others to avoid this approach over concerns about brush wear and its associated dust. Will brush wear be an issue here? That remains to be seen, but we doubt it. The brush array is sequestered in an isolated compartment, with a removable cover enabling easy access. The lack of permanent magnets avoids the issues of rising rare-earth costs and the environmental impact of mining. This scheme also makes it possible to vary the strength of the rotor's magnetic field, which enables further optimization. Still, power is required to energize this rotor, making these motors less efficient, notably at low speeds when the energy needed to create the field represents a greater percentage of the total consumption.
The appearance of the current-excited AC synchronous motor is so recent in the short history of EVs that it illustrates just how early we are in the development curve. There's abundant room for fresh ideas, and there have already been major pivots, not least including Tesla's move away from the induction-motor concept that is the basis for its own brand name and logo and toward permanent-magnet synchronous motors. And we're barely a decade into the modern EV era—we're just getting started.
Dan Edmunds From the April 2022 issue of Car and Driver. Caranddriver ev-motors-explained
Electric Cars 101
It has to do with magnetism and the natural interplay between electric fields and magnetic fields. When an electrical circuit closes allowing electrons to move along a wire, those moving electrons generate an electromagnetic field complete with a north and a south pole. When this happens in the presence of another magnetic field—either from a different batch of speeding electrons or from Wile E. Coyote's giant ACME horseshoe magnet, those opposite poles attract, and like poles repel each other.
Electric car motors work by mounting one set of magnets or electromagnets to a shaft and another set to a housing surrounding that shaft. By periodically reversing the polarity (swapping the north and south poles) of one set of electromagnets, the EV motor leverages these attracting and repelling forces to rotate the shaft, thereby converting electricity into torque and ultimately turning the wheels. Conversely—as in the case of regenerative braking—these magnetic/electromagnetic forces can transform motion back into electricity.
How Electric Cars Work: AC or DC?
The electricity supplied to your home arrives as alternating current (AC), so-called because the north/south or plus/minus polarity of the power changes (alternates) 60 times per second. (That is, in the United States and other countries operating at 110 volts; countries with a 220-volt standard typically use 50-Hz AC.) Direct current (DC) is what goes into and comes out of the + and - poles of every battery. As noted above, motors require alternating current to spin. Without it, the electromagnetic force would simply lock their north and south poles together. It's the cycle of continually switching north and south that keeps an electric car motor spinning.
Today's electric cars are designed to manage both AC and DC energy on board. The battery stores and dispenses DC current, but again, the motor needs AC. When recharging the battery, the energy comes into the onboard charger as AC current during Level 1 and Level 2 charging and as DC high-voltage current on Level 3 "fast chargers." Sophisticated power electronics (which we will not attempt to explain here) handle the multiple onboard AC/DC conversions while stepping the voltage up and down from 100 to 800 volts of charging power to battery/motor system voltages of 350-800 volts to the many vehicle lighting, infotainment, and chassis functions that require 12-48-volt DC electricity.
What Types of Motors?
DC Motor (Brushed): Yes, we just said AC makes the motor go around, and these old-style motors that powered early EVs of the 1900s are no different. DC current from the battery is delivered to the rotor windings via spring-loaded "brushes" of carbon or lead that energize spinning contacts connected to wire windings. Every few degrees of rotation, the brushes energize a new set of contacts; this continually reverses the polarity of the electromagnet on the rotor as the motor shaft turns. (This ring of contacts is known as the commutator).
The housing surrounding the rotor's electromagnetic windings typically features permanent magnets. (A "series DC" or so-called "universal motor" may use an electromagnetic stator.) Advantages are low initial cost, high reliability, and ease of motor control. Varying the voltage regulates the motor's speed, while changing the current controls its torque. Disadvantages include a lower lifespan and the cost of maintaining the brushes and contacts. This motor is seldom used in transportation today, save for some Indian railway locomotives.
Brushless DC Motor (BLDC): The brushes and their maintenance are eliminated by moving the permanent magnets to the rotor, placing the electromagnets on the stator (housing), and using an external motor controller to alternately switch the various field windings from plus to minus, thereby generating the rotating magnetic field.
Advantages are a long lifespan, low maintenance, and high efficiency. Disadvantages are higher initial cost and more complicated motor speed controllers that typically require three Hall-effect sensors to get the stator-winding current phased correctly. That switching of the stator windings can result in "torque ripple"—periodic increases and decreases in the delivered torque. This type of EV motor is popular for smaller vehicles like electric bikes and scooters, and it's used in some ancillary automotive applications like electric power steering assist.
Permanent-Magnet Synchronous Motor (PMSM): Physically, the BLDC and PMSM motors look nearly identical. Both feature permanent magnets on the rotor and field windings in the stator. The key difference is that instead of using DC current and switching various windings on and off periodically to spin the permanent magnets, the PMSM functions on continuous sinusoidal AC current. This means it suffers no torque ripple and needs only one Hall-effect sensor to determine rotor speed and position, so it's more efficient and quieter.
The word "synchronous" indicates the rotor spins at the same speed as the magnetic field in the windings. Its big advantages are its power density and strong starting torque. A main disadvantage of any EV motor with spinning permanent magnets is that it creates "back electromotive force" (EMF) when not powered at speed, which causes drag and heat that can demagnetize the motor. This motor type also sees some duty in power steering and brake systems, but it has become the motor design of choice in most of today's battery electric and hybrid vehicles.
Note that most permanent-magnet motors of all kinds orient their north-south axis perpendicular to the output shaft. This generates "radial (magnetic) flux." A new class of "axial flux" motors orients the magnets' N-S axes parallel to the shaft, usually on pairs of discs sandwiching stationary stator windings in between. The compact, high-torque axial flux orientation of these so-called "pancake motors" can be applied to either BLDC or PMSM type motors.
AC Induction: For this motor, we toss out the permanent magnets on the rotor (and their increasingly scarce rare earth materials) and keep the AC current flowing through stator windings as in the PMSM motor above.
Standing in for the magnets is a concept Nikola Tesla patented in 1888: As AC current flows through various windings in the stator, the windings generate a rotating field of magnetic flux. As these magnetic lines pass through perpendicular windings on a rotor, they induce an electric current. This then generates another magnetic force that induces the rotor to turn. Because this force is only induced when the magnetic field lines cross the rotor windings, the rotor will experience no torque or force if it rotates at the same (synchronous) speed as the rotating magnetic field.
This means AC induction motors are inherently asynchronous. Rotor speed is controlled by varying the alternating current's frequency. At light loads, the inverter controlling the motor can reduce voltage to reduce magnetic losses and improve efficiency. Depowering an induction motor during cruising when it isn't needed eliminates the drag created by a permanent-magnet motor, while dual-motor EVs using PMSM motors on both axles must always power all motors. Peak efficiency may be slightly greater for BLDC or PMSM designs, but AC induction motors often achieve higher average efficiency. Another small trade-off is slightly lower starting torque than PMSM. The GM EV1 of the mid-1990s and most Teslas have employed AC Induction motors.
Reluctance Motor: Think of "reluctance" as magnetic resistance: the degree to which an object opposes magnetic flux. A reluctance motor's stator features multiple electromagnet poles—concentrated windings that form highly localized north or south poles. In a switched reluctance motor (SRM), the rotor is made of soft magnetic material such as laminated silicon steel, with multiple projections designed to interact with the stator's poles. The various electromagnet poles are turned on and off in much the same way the field windings in a BLDC motor are. Using an unequal number of stator and rotor poles ensures some poles are aligned (for minimum reluctance), while others are directly in between opposite poles (maximum reluctance). Switching the stator polarity then pulls the rotor around at an asynchronous speed.
A synchronous reluctance motor (SynRM) doesn't rely on this imbalance in the rotor and stator poles. Rather, SynRM motors feature a more distributed winding fed with a sinusoidal AC current as in a PMSM design, with speed regulated by a variable-frequency drive, and an elaborately shaped rotor with voids shaped like magnetic flux lines to optimize reluctance.
The latest trend is to place small permanent magnets (often simpler ferrite ones) in some of these voids to take advantage of both magnetic and reluctance torque while minimizing cost and the back EMF (or counter-electromotive force) high-speed inefficiencies that permanent-magnet motors suffer.
Advantages include lower cost, simplicity, and high efficiency.
Disadvantages can include noise and torque ripple (especially for switched reluctance motors).
Toyota introduced an internal permanent-magnet synchronous reluctance motor (IPM SynRM) on the Prius, and Tesla now pairs one such motor with an AC induction motor on its Dual Motor models. Tesla also uses IPM SynRM as the single motor for its rear-drive models.
Electric motors may never sing like a small-block or a flat-plane crank Ferrari. But maybe, a decade or so from now, we'll regard the Tesla Plaid powertrain as fondly as we do those engines, and every car lover will be able to describe in intimate detail what kind of motors it uses.
Frank Markus, RyanLugo Motortrend How-electric-cars-work-ev-differences-definitions
How do EVs affect the electric grid?
As the mobility market continues to shift toward EVs, many observers are considering the effects on global energy grids. Generally, electrical capacity will need to expand to support the growing number of EVs on the roads, but analysis suggests that growth in e-mobility will not drive substantial increases in power demand in the short to medium term.
One solution to mitigate much of the impact of EV customers on electric grids is “managed charging.” That approach entails a combination of incentives for customers to use off-peak charging times and moves to enable utilities to turn charging on and off for areas or individuals, based on real-time use. Vehicle-to-grid (V2G) technology can facilitate managed charging.
How does the rise of EVs affect natural resources?
The rise of EVs has direct implications for the supply chain of raw materials. The greater demand for EVs in recent years has meant greater demand for raw materials and EV inputs, including metals and ores such as cobalt, lithium, and nickel. Demand for lithium carbonate, for example, could rise to three million to four million metric tons in 2030, from 500,000 metric tons in 2021.
More broadly, when it comes to sustainability and the mobility industry, much attention is paid to bringing down tailpipe emissions—understandable, since they account for 65 to 80 percent of the emissions automobiles generate. But it’s worth noting that efforts to reduce material emissions will be crucial, over time, to realizing the potential of the zero-carbon car. Mobility’s longer-term net-zero transition entails both opportunities and risks, and coordinated responses from the public and private sectors can help ease the shift.
Is the automotive future electric?
Simply put, yes. Mainstream EVs will transform the automotive industry and help decarbonize the planet. There is essentially no other solution to decarbonize passenger transport. Hydrogen will probably not play a significant role in passenger mobility as EV-charging speeds and ranges increase and green hydrogen remains too expensive for the average private BEV owner. Other options have different limitations: synthetic fuels are too expensive, biofuels are not abundantly available—and both release emissions.
- Regulation. National and municipal governments have introduced new regulations and incentives to accelerate the shift to sustainable mobility. In the United States and Europe, new regulatory targets aim for an EV share of 50-plus percent by 2030. A number of countries, including those in the European Union, have gone well beyond this, announcing accelerated timelines for ICE sales bans in 2030 or 2035. Many national governments are also offering EV subsidies.
- Consumer behavior. People are more accepting than ever of alternative, sustainable mobility options. In 2021, the number of inner-city trips with shared bicycles and e-scooters rose by 60 percent year over year. Interest in EVs reflects this consumer shift: more than 45 percent of car customers in 2021 considered buying an EV.
- Technology. Automotive-industry players are accelerating the development of new concepts of mobility, including electric, connected, autonomous, and shared vehicles. These technology innovations will help reduce the cost of EVs and make electric shared mobility a real alternative to owning a car.
How are chip shortages affecting the EV market?
The shortage is the result of a complicated confluence of events, including struggles during the COVID-19 pandemic, a lack of new capacity, geopolitical tensions, limited stock, and contract terms unique to the auto industry. The scarcity lowers car production and is responsible for billions of dollars of lost revenue.
Given the shortage and resulting losses, automotive EV-component manufacturers will need to rethink how and when they order semiconductors to meet the growing demand for EVs.
How can ICE businesses stay competitive?
The last hundred years are known in the automotive industry as the ICE Age, when vehicles with internal-combustion engines dominated the roads and skies. While most vehicles on the road are still powered by ICEs today, EVs are slowly replacing ICE vehicles, especially in the European Union, China, and the United States. However, emerging markets will still use ICE vehicles into the 2040s, and aftermarket components will still be used through the 2050s and beyond.
To stay competitive, ICE suppliers need to explore ways to navigate the energy transition—and revisit their portfolios—as electric mobility continues to grow.
What is the Electric Vehicle Index?
McKinsey’s Electric Vehicle Index (EVI) tracks the dynamic e-mobility market in 15 countries, focusing on BEVs and PHEVs. It emphasizes two key factors:
- Market demand, by analyzing the share of EVs in the overall market and the factors fueling the growth and adoption of EVs in each country. These factors include incentives (such as subsidies), existing infrastructure, and the range of available EVs.
- Industry supply, by examining how many of a country’s manufacturers are producing EVs and EV components, such as e-motors and batteries.
The EVI then assesses the key performance indicators in each country’s EV market and plots them on a scale from 0 to 5 for both supply and demand factors. The resulting analysis offers interesting insights on the regional dynamics and emerging trends of EVs.
.Articles referenced:
- “Can the automotive industry scale fast enough?,” May 12, 2022, Russell Hensley, Kevin Laczkowski, TimoMöller, and Dennis Schwedhelm
- “ICE businesses: Navigating the energy-transition trend within mobility,” March 14, 2022, Will Han, Asad Husain, SrikantInampudi, Brian Loh, Yogesh Malik, and Samuel Stone
- “Electrifying the bottom line: How OEMs can boost EV profitability,” November 11, 2021, Thomas Gersdorf, Andreas Haunreiter, Russell Hensley, Patrick Hertzke, Ruth Heuss, Stefan Pöhler, Patrick Schaufuss, and Andreas Tschiesner
- “Why the automotive future is electric,” September 7, 2021, Julian Conzade, Andreas Cornet, Patrick Hertzke, Russell Hensley, Ruth Heuss, TimoMöller, Patrick Schaufuss, Stephanie Schenk, Andreas Tschiesner, and Karsten von Laufenberg
- “Building better batteries: Insights on chemistry and design from China,” April 22, 2021, NicolòCampagnol, Mauro Erriquez, Dennis Schwedhelm, Jingbo Wu, and Ting Wu
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