Electric car or plug-in hybrid? How does it actually work? And how far can I get on a single charge? We provide answers to important (technical) questions about e-mobility.
Electric cars are the future. But which electric vehicle is best suited to my needs? A purely electric car or rather a hybrid vehicle? Which factors are decisive? And how does an electric motor actually work? We will show you the differences and give you useful tips for more range.
The demand for electric cars is steadily increasing. This is partly due to attractive subsidies, but also to increasingly powerful technical components, improved charging infrastructure and growing environmental awareness. But what exactly makes an electric car so special?
The most important components of an electric car include
The so-called skateboard architecture has proven to be particularly effective for the placement of these components: The battery is installed between the axles in the underbody, while the electric motor and power electronics are located on the front and/or rear axle.
Electric cars are vehicles that are either fully or partially powered by an electric motor. In addition to fuel cell vehicles, these include the following variants:
Purely electrically powered vehicles, so-called Battery Electric Vehicles (BEV), are driven by an electric motor that receives its energy from a battery. They therefore do not require fossil fuels. The built-in battery is charged externally via the power grid - at a public charging station, on a mobile charger or via a private wallbox. The battery can also absorb braking energy (recuperation) and feed it back into the battery.
Plug-in hybrids have both a conventional drive system and an electric drive. The special feature: a plug-in hybrid can be charged in three different ways. Via the combustion engine, by means of brake energy recovery (recuperation) or - as the name aptly puts it - from the outside via a plug. Another plus point: plug-in hybrids have a fairly large battery. This means that they can also drive purely electrically for a certain period of time and achieve higher speeds. A control system regulates which type of drive is used at which time and automatically selects the most energy-efficient solution.
In micro-hybrids, the battery is only charged by recuperation. Unlike other hybrid variants, no additional energy can be generated here. For example, there is no external charging option.
In mild hybrids, the electric drive supports the combustion engine. In addition, more energy is recovered through regenerative braking than with micro-hybrids. Purely electric driving is not possible.
In a full hybrid, the combustion engine supports the electric motor as efficiently as possible. Thanks to its large battery, purely electric driving is very possible. The range depends on the model and driving style. In contrast to a plug-in hybrid, the battery of a full hybrid cannot be charged externally and stores less energy.
A range extender increases the range of an electric car. Many e-vehicles are equipped with a battery of smaller or medium capacity to make the car more affordable for the buyer. The disadvantage: the range is correspondingly shorter.
The range extender, a small combustion engine with a generator, supports the performance of the battery and enables an additional range of up to 100 kilometers. It is therefore comparable to a hybrid vehicle.
There are also different drive systems for the various hybrids, which differ in the way the motors are arranged:
In a serial hybrid drive, only one motor is in operation at any one time - the combustion engine or the electric motor.
In this case, the name lives up to its promise: in parallel hybrid drive, the power of both engines - the combustion engine and the electric motor - is added together.
Mixed hybrids or power-split hybrids combine a serial hybrid drive with a parallel hybrid drive. Depending on requirements, the combustion engine can be used as a power generator (serial) or directly for propulsion (parallel).
The battery plays a central role for electric cars. This is because the range and price of a vehicle depend on its performance.
The high-voltage battery is comparable to the tank of a conventional car. Energy is stored there in the form of electricity. Lithium-ion batteries are currently mostly used for the battery, as they are durable, can be charged quickly and can also store a lot of electricity.
The low-voltage battery, on the other hand, is responsible for the on-board electronics, i.e. the radio, windshield wipers, lights or cruise control. Energy gained through recuperation can be stored in the low-voltage battery.
Battery technology is constantly evolving. Energy density, for example, has almost doubled in recent years - and at significantly lower prices. For e-buyers, this means
For the same money, you can now get far more power with a lower battery weight than just a few years ago.
In order to deliver top performance, the battery must meet certain requirements:
An example: Let's say the battery of an electric car has an energy density of 140 watt hours per kilogram. The electric car itself consumes around 20,000 watt hours per 100 kilometers. This means that the battery would have to weigh around 143 kilograms in order to drive 100 kilometers. This means that the higher the energy density, the lighter the battery.
A heavy battery increases the car's energy consumption and therefore has a negative effect on the range.
Another important component of the battery is the battery management system. Its task is to control the temperature in the individual battery cells and to compensate for voltage fluctuations during charging in order to prevent damage to the battery.
The electric motor draws the required current via the power electronics, which form the link between the motor and the battery. The central components of the electric motor are the stator and rotor:
The electric motor thus turns electrical energy into mechanical energy and converts the current from the battery into a suitable form, strength and frequency. It is extremely efficient, reliable and virtually noiseless.
The charging connection is the plug device used to charge the electric car. Charging takes place via a so-called wallbox, public charging stations or a mobile charger. The alternating current from the power grid is converted into the direct current required for the electric car either by the charger integrated in the vehicle, also known as the on-board charger, or by the charging station itself in the case of direct current fast charging stations. The latter guarantees a significantly faster charging process.
Range is one of the most important criteria when deciding on an electric car. This is because many potential buyers are still worried that their vehicle's battery could suddenly run out halfway through the journey.
However, the fact is that around 80 percent of Germans travel no more than 40 kilometers by car per day - the range of an electric car is more than enough for that! And thanks to improved battery capacities, ranges of between 200 and 600 kilometers are now even possible, depending on the vehicle. For short-distance drivers, it is therefore only important to have a charging facility nearby - either directly at or near home or at work.
To ensure that the battery lasts as long as possible over long distances, three factors need to be taken into account: the energy density of the battery, consumption and temperature.
Point 1 is simple: a battery with a higher energy density can store more energy. More energy means more range.
Consumption? The more energy is consumed, the faster the e-car has to be recharged. But what is the best way to reduce consumption? Here are three tips:
Tip 1: Drive with foresight.
By anticipatory, early and careful braking, the braking force can be converted back into electricity through recuperation, thus increasing the range.
Tip 2: Don't drive too fast.
Driving slowly means lower energy consumption and therefore a longer range. Average speeds between 30 and 100 km/h are ideal. On highways, you should stick to the recommended speed - this is not only good for the battery, but is also a lot safer.
Tip 3: Sensible heating and cooling.
It's too cold in the car in winter and too hot in summer. The patent solution for many: excessive heating or cooling. But this is only at the expense of the battery and therefore the range. Therefore: heating and cooling yes, but please in moderation. Sitting in the car in a T-shirt in winter, for example, is not absolutely necessary. And in summer, it can also help to air the car and enjoy the breeze.
But: open windows and a running air conditioning system are an absolute no-go and reduce the range of the electric car unnecessarily!
This brings us to point 3, the temperature. The batteries in electric cars work best at mild temperatures. If it is colder, the battery drains faster. And heating the electric car also puts a strain on the battery - the range drops by around 41 percent on average in cold weather. In midsummer, the range drops by around 17 percent due to the increased energy consumption caused by the air conditioning.
This is also confirmed by studies conducted by the American Automobile Association. Various tests were used to determine the range of electric cars in summer and winter and a rule of thumb was used to calculate the actual range:
Manufacturer's specification in km - (17% or 41% of the manufacturer's specification in km) = summer/winter range in km
The effects of battery temperature on the range and service life of an electric car:
With all the technology that goes into an electric car, the question arises: how safe are electric vehicles? In general, every car that receives a license must meet certain requirements by law. This is the only way to ensure maximum safety. It doesn't matter whether the vehicle is powered by petrol, diesel, gas or electricity.
For e-cars, for example, it is stipulated that all electrical components must be designed to be "intrinsically safe". This means that if there is a fault in the system, the battery's current flow is stopped so that no more voltage is present. In addition, the battery is installed in the underbody of the vehicle so that it is well protected from external influences. The risk of fire is therefore no higher with an electric car than with any other vehicle.
But what happens if ...
In the event of a breakdown, the battery generally poses no danger whatsoever due to the good protection mechanisms. If the vehicle no longer starts or there is another problem, a breakdown service can help.
Important: Work on electric cars may only be carried out by persons who are trained to do so!
Thanks to the immediate interruption of the current flow, electric cars are usually very safe here too. It can only become critical if, despite all safety precautions, the battery is deformed in a very serious accident and the built-in protective mechanisms are impaired. Possible consequence: a so-called "thermal runaway", i.e. a fire in the traction battery.
However, a diesel or petrol vehicle can also catch fire in a serious crash - so there is no increased risk of fire in an accident involving an electric car.
An electric car is therefore in no way inferior to a combustion engine in terms of safety.