Electric cars and plug-in hybrids explained

5 min reading time
Which kinds of electric cars can you buy nowadays? What makes a plug-in hybrid different from a mild hybrid? Read on to find the answers in our comparison of electric cars.

2 July 2020

Sooner or later, the majority of drivers will be making the switch from petrol cars to an electric vehicle. The advantages are obvious, above all for the environment, because engines powered by electricity don’t give off emissions, so electric cars are locally emission-free. At the moment, electric vehicles (EVs) are more expensive than conventional ones. However, with EVs comes a variety of savings, like lower operating and maintenance costs, that their fuel-powered counterparts don’t have. On top of this, manufacturers offer refunds for EVs and many countries have incentives and tax credits for them.

Electric cars are obviously a practical choice, but that doesn't mean they aren't fun. When you're at a traffic light, you’ll have enough torque to smoke the guy next to you when the light turns green, but you’ll be able to do it in a sneaky way because the engine is so quiet.

Technological advances in electric mobility enable carmakers to offer an ever-expanding range of vehicles, which makes it easy to lose track of all the developments. Some buyers are perfectly happy with a plug-in hybrid, while others want a fully electric car. Our comparison of electric cars explains the different kinds of designs. We use the term EV to include electric vehicles as well as hybrids.

As an e-mobility pioneer, the BMW Group has reached another electromobility milestone and already delivered half a million electrified cars to customers worldwide until the end of 2019. On top of that BMW aims to have one million electrified vehicles on the roads within two years and contribute towards effective climate protection.

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What kinds of electric cars are there? Click here to find out:

Fully electric cars

How does an electric vehicle work? As opposed to a combustion engine, an EV uses electricity from a battery rather than the combustion of fuel to power the engine. The capacity of the battery determines the EV's range (how far it can go on a single charge of the battery).

An all-electric vehicle (BEV – battery electric vehicle) runs strictly on electricity. It does not have a combustion engine, which is why it does not produce emissions locally. For this reason we have given it the maximum number of points for environmental friendliness in our comparison of electric vehicles.

The problem is that many motorists are worried about range – a worry that is generally unfounded. Today, most BEVs have a range of over 185 miles and most motorists in the USA drive less than 60 miles a day.

By using a range extender, motorists can breathe easy in this regard. A range extender is a petrol-powered generator that feeds electricity exclusively to the battery when its charge is nearly drained. In a BEV, this generator does not directly power the car, because if it did, it would be a hybrid.

Another advantage of BEVs (Battery Electric Vehicles) is that they have the most country-specific incentives and tax credits. Fully electric vehicles are ideal for people who can charge their battery at home or at work. Nowadays, more and more public charging stations are being opened, especially in metro areas and along motorways. This means that in the future, it will be more and more easy to make long-distance trips.

Range                    ***
Infrastructure      ***
Sustainability     *****

Hybrid car

What is a hybrid car? In contrast to an electric vehicle, a hybrid electric vehicle (HEV) has both a combustion and an electric engine. Depending on the car, both motors can either be independent of one another or can work in tandem.

The degree to which hybrids function as an electric vehicle depends on their electric performance, their electric range and the range of their recharging system. There are two types of HEVs: mild hybrids and plug-in hybrids.

Mild hybrid – electric motor boosts combustion engine

How does a mild hybrid work? The electric motor of a mild hybrid assists the combustion engine. It kicks in when a great deal of fuel is being consumed, particularly during startup. This enables mild hybrids to reduce their fuel consumption and emissions. Batteries are automatically recharged with regenerative braking.

Mild hybrid vehicles – also known as 48-volt hybrids or MHEVs (mild hybrid electric vehicles) – have an electric motor that assists the combustion engine. The electric motor kicks in when a lot of fuel is being burned, particularly during startup. It can also serve to boost the engine's power during acceleration.

The battery is exclusively charged via regenerative braking, which captures the energy created by the friction of braking, converts it to electricity and stores it in the battery. Mild hybrids do not use charging stations.

The main advantage of a mild hybrid is its fuel consumption, that is 0.1 gallons (per 62 miles) lower than that of a petrol car. Since less fuel is consumed, the vehicle can go farther on a full tank of petrol or diesel. Because the main propulsion system is powered by a combustion engine, mild hybrids benefit from the ubiquity of petrol stations. So mild hybrids are ideal for motorists who are looking for maximum range combined with low fuel consumption and who don’t want to worry about charging the battery.

Because they consume less fuel, mild hybrids have lower emissions, but the electric motor is not capable of powering the car on its own. This is why mild hybrids get none of the incentives that are offered for EVs and why they receive only two points for sustainability in our comparison of electric vehicles.

Range                    *****


What is a plug-in hybrid? The best of both worlds

What is a plug-in hybrid? A plug-in hybrid vehicle (PHEV) has both a combustion engine and an electric motor. Each one is capable of powering the vehicle on its own. Plug-in hybrids use regenerative braking as their energy source, but they can also be plugged in to recharge the battery.

While a mild hybrid car captures electric energy solely while it’s being driven, and thus can only supply a limited amount of power, a plug-in hybrid – PHEV (plug-in hybrid vehicle) – is also capable of recharging its battery when it’s parked at a charging station. This significantly expands the electric range of a plug-in hybrid like the 2018 BMW 530e iPerformance, which can drive 28 miles only on electricity with a fully charged battery. Over the next few years, technological advances will significantly improve the range of electric motors – as well as that of all battery-powered cars.

Many PHEV owners can already manage most of their trips on electricity because daily commutes are generally less than 30 miles. It depends on how much you pay for electricity, but you will likely be saving a great deal. If the electric charge is depleted, then the combustion engine takes over, so you don’t have to worry about finding a charging station.

PHEVs are ideal for motorists who want to use their cars in a variety of ways. You can use the electric motor for daily commutes, but also take advantage of the great range and flexibility of a petrol engine when you go on longer trips. In addition, owners can benefit directly from financial incentives for electric vehicles in certain countries and indirectly from lower taxes from reduced CO2 emissions.

Range                    *****
Infrastructure      *****
Sustainability      ****

CO2 emissions 49-47 g/km (combined)
Fuel consumption 2,2-2,1 l/100 km (combined)
Power consumption 13,6-13,3 kWh/100 km (combined)

Fuel cell

How does a fuel cell vehicle work? Cars powered by hydrogen are also considered EVs because oxygen and hydrogen are converted to electric energy, which then powers the electric motor with a battery. They can also recapture the energy that is lost during braking and store it in a battery.

Fuel cell electric vehicles (FCEV) create their own electricity on board. Hydrogen in the fuel cell reacts with oxygen in the air, thereby generating electricity, which is used to power the electric motor, similar to a BEV. As a result, they only emit water vapor and warm air. However, it does have an ecological disadvantage because the production of hydrogen requires a large amount of electricity. On top of this, the hydrogen must be transported from the production facility to petrol stations.

FCEVs have a range similar to that of future battery-powered EVs. One significant advantage of FCEVs is the short time it takes to fill the tank – a matter of minutes - just like it is with a petrol/diesel car. One problem, however, is that filling stations are few and far between and little progress is being made in adding new ones. Should this change in the future then there would be little difference between operating a FCEV and a petrol car.

It is also still very expensive to manufacture fuel cell systems. One of the main reasons for this is that platinum is needed for the catalytic converter.

Range                    ****

Every driver is different and has their own personal needs. Luckily, there are a lot of different types of engines out there to serve these needs. And each kind of vehicle offers drivers certain advantages. Even conventional petrol or diesel cars have their place in the mobility mixture of the future for specific user groups and for special areas of application.

The future will also likely see a combination of several technologies. BMW has prepared for this with its innovative vehicle platform, which can accommodate the three types of propulsion systems, the powertrain of a combustion engine as well as that of a plug-in hybrid or a fully electric vehicle. The production model of a fully electric vehicle, the BMW Vision iNEXT (launch in 2021) will be the first vehicle with this universal propulsion platform.

Illustrations: Cyprian Lothringer


The BMW i3.

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