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Technical Knowledge

Electric cars: basic technical knowledge

The electric motor simply explained

Every electric motor needs a charging station or energy source as a power supply. Electric current is then converted into mechanical energy. In the case of car batteries, a wall box, charging station or conventional household socket is needed for charging. 
How an electric motor works

The motor of an electric car converts the current from the battery into mechanical energy. This is done by a fixed magnetic part (stator) and a moving part (rotor) that is made magnetic by electricity. If two positive poles are facing each other due to the electrical charge, they repel each other - and the moving part of the electric motor rotates.

To understand this function of the electric motor, you only need a basic knowledge of magnetism: like poles repel and different ones attract. With electric current, it is possible to make a non-magnetically charged part magnetic. And the polarity can also be influenced, depending on the direction in which the current flows. With every half turn, the direction of the current changes automatically. This ensures that the machine remains permanently in motion and does not stop at dead centre. 

Electrifying driving dynamics
High efficiency, low running costs, zero emissions - so much for the many sensible reasons in favour of a car with an electric motor. But what's it like to drive an Opel electric car? Look forward to torque that's there instantly, giving you a whole new kind of driving pleasure. 
High efficiency
Perhaps the greatest advantage of an electric motor is its high efficiency - that is, the ratio of power used to power consumed. While up to a third of the energy in a combustion engine is lost through heat loss, the electric car uses a sensational 95% of the available energy for driving. 

The electric motor in detail

The electric car drivetrain

Electric motors develop similar torque at low as well as at high speeds. Theoretically, therefore, a rigid connection between the motor and the drive shaft would suffice for them. In practice, however, an input gearbox is usually used as a so-called reduction gear, which reduces the speed of the motor by a factor of about 1:10.

The acceleration in an electric car is comparable to that of an automatic transmission. After starting the engine, all you have to do is shift to "D" for Drive - and you're off to a dynamic start!

The electric car powertrain

The motor of an electric car consists of two electromagnets - stator and rotor. The stator is immobile and generates a constant magnetic field with the help of direct current. The rotor is rotatable and produces its magnetic field with alternating current. The two magnets alternately attract and repel each other. The rotor rotates - and thus sets the car in motion.

Electric cars drive with a what is known as a synchronous alternating current motor. It gets its energy from power electronics. It converts the current from the battery into the right shape, strength and frequency. Incidentally, the stator is always made of soft magnetic iron. To avoid eddy currents in the magnetic field, it is usually also laminated. This means that several layers of sheet metal insulated from each other are mounted on top of each other. This enables the stator to generate or guide the magnetic field.

The electric car inverter
The inverter is also called a converter. This is because it has the task of converting the 3-phase AC voltage of the electric motor into a DC voltage for charging the battery when braking. Conversely, when the electric motor is driven, the battery's DC voltage is converted into a 3-phase AC voltage. 

Interesting information about electric cars

How does an electric motor work?

An electric motor converts electrical current into kinetic energy. And it does so much more efficiently than a car with an internal combustion engine. In a hybrid, the electric motor supports the combustion engine, thus ensuring lower fuel consumption.

Compared to the combustion engine, the motor of an electric car has a much simpler design - and is also lighter. Inside it, changing magnetic fields are converted into movement. To be more precise, permanently integrated stators, or in other words magnets, constantly change their poles due to the energy from the battery. The rotor sitting in the middle or in the stator, another magnet, is thus alternately attracted and repelled. This causes it to rotate and finally sets the wheels in motion. 

What types of electric cars are there?

There are purely electric vehicles (BEV), plug-in hybrids (PHEV) and full hybrids (SHEV). 

(SHEV). Hybrids, however, have an internal combustion engine that is supported by the electric motor. This is charged by an external power source in the case of plug-in hybrids and by recuperation (recovery of braking energy) in the case of full hybrids. Battery-powered vehicles with an additional small combustion engine and generator are called range extenders. Here, the combustion engine only starts to generate additional electricity for the battery.

All Opel electric cars have a lithium-ion battery, as this material is the fastest, most abundant and most voluminous to charge. The battery of an electric car consists of individual modules that can be replaced individually and are in turn made up of many battery cells. The more modules, the greater the range of the car. Modern systems rely on so-called "pouch cells", which are similar in design to mobile phone batteries. In addition to this so-called high-voltage battery, there is also a 12-volt battery that supplies the on-board electronics.

What are the advantages of electromobility?

Electromobility allows you to travel locally with zero emissions. Electric cars are also more economical than vehicles with conventional combustion engines - and require less maintenance. And thanks to the direct, powerful drive, they are not only great fun to drive, you will experience a completely new dimension of driving.

Electromobility allows you to travel locally with zero emissions. Electric cars are also more economical than vehicles with conventional combustion engines - and require less maintenance. And thanks to the direct, powerful drive, they are not only great fun to drive, you will experience a completely new dimension of driving.  

Why are electric cars cheaper in the long-term?

Lower fuel and electricity costs, tax breaks and purchase bonuses: it pays to switch to electric mobility. For example, the maintenance and repair costs for electric cars are significantly lower than for combustion engines. This is because fully electric vehicles have fewer moving parts in the drive train and engine. And that ensures less wear and tear.