Regenerative braking plays a very important role in electric vehicles and hybrid vehicles alike. It’s an ‘energy recovery system’ which creates electricity from the car’s kinetic energy that would normally be lost as heat from the brakes. The electricity produced would then be used to recharge the battery. In simple terms, normal braking uses friction, with the brake callipers pressing on the disks. This process produces kinetic energy which would be lost.
However, electric cars are much more efficient from this point of view and regenerative braking allows energy to be recovered and charges the accumulators, which increases a car’s range. This is such a useful and convenient trick. Just think of how often you’re stopping and starting in a city environment. In this situation, an electric vehicle can recover lots of energy, reducing energy consumption drastically.
Energy recovery can also be very useful when making long hill descents. You can recover a good part of the energy you consumed during the hill climbs. In modern electric cars, regenerative braking can be regulated, and the efficiency can be increased or reduced in line with the driving situation.
For example, it can be increased to maximum in urban areas or on a descent, and it can be reduced to a minimum when you’re driving on long sections of main road or motorway when you don’t want to brake so often. Let’s talk a bit more about this concept.
How exactly does energy recovery work?
Without getting too technical, energy recovery occurs by inverting your electric motor’s method of operation. When you’re driving, the engine uses the energy contained in the battery to move the wheels. However, when decelerating or braking, the motor acts as a generator, transforming the kinetic energy that would be lost as heat, into electricity.
An electric motor contains two key components: the stator and the rotor. The stator is the stationary part and contains a type of frame that has wires coiled around it. Electric current circulates within this frame. So it creates a magnetic field which rotates.
The rotor, instead, is the mobile part of the motor. This is inserted into the stator and is also equipped with wires or magnetic that create a magnetic field. The interaction between the two magnetic fields makes the rotor move. Since it’s attached to the transmission, it provides the torque required to make the wheels turn.
When a vehicle brakes or decelerates, the electric motor works the opposite way, transforming it into a sort of generator. So, instead of consuming energy, it produces it. As we said, the current produced is then used to recharge the accumulator.
Thanks to regenerative braking, you’re not just slowing the car down, you’re also charging the battery.
The advantages of regenerative braking
The ability to charge the battery is only one of the advantages of regenerative braking. It’s also able to slow down your car in such a way that it makes driving more comfortable. On some models, the intensity of recovery is so great that you only need to lift your foot off the accelerator to decisively slow down your car to a stop. Obviously, regenerative braking cannot yet be a substitute for traditional braking, but once measures have been taken, you can use it more often to decelerate your car more ‘smoothly’ (motorway exits, stop signs, red traffic lights, etc.).
And since the traditional brakes would be used less, they’ll suffer less wear and tear. Brake pads, especially, can last much longer than on a traditional petrol or diesel car.
As we pointed out earlier, on some models you can ‘play’ with the level of regenerative braking by using the appropriate commands (usually the paddles behind the steering wheel). In this way, as well as managing the intensity of energy recovery, you can also adjust the ‘force’ with which the car decelerates.
So, by using energy recovery correctly, you can improve the range of an electric car. You should know that if the battery is charged at 100% or if the accumulator hasn’t reached optimum operating temperature (this happens especially in winter), regenerative braking may not be quite so effective. This is important to remember, even if, over time, you can gradually learn to manage it in all conditions