Regenerative braking: what it is and how it works
A key technology in electric cars is regenerative braking, a system that improves the energy efficiency of zero-emission cars. This mechanism is used not only in electric vehicles, but also in plug-in hybrid, mild hybrid and full hybrid cars to optimize battery and electric motor performance. This simple process allows you to recharge the battery without using an external source, using the energy available while driving which is generally wasted. Let's find out how braking energy recovery works and what advantages it offers in the field of sustainable mobility.
What is regenerative braking for
All cars use friction to slow the vehicle, which is exerted by the calipers on the brake discs to reduce the speed of the car. During this process, a large amount of kinetic energy is generated, which is transformed into heat and is wasted by dispersing in the air and being partially absorbed by the brakes themselves. For this reason, in motor racing, where braking is particularly intense, the high heat generated by decelerations makes the brakes hot. This is dissipated heat, energy that can be recovered through a regenerative braking system making cars more energy efficient. Regenerative braking, therefore, is used to recover the braking energy that would otherwise be dispersed during decelerations. This energy is used to recharge the lithium-ion battery of electric and hybrid cars, converting the kinetic energy released by braking into electrical energy for recharging the vehicle's accumulators.
How regenerative braking works
Let's see now how the regenerative braking of hybrid and electric cars works in detail. This process begins when the driver presses the brake pedal, an action that involves the reverse operation of the electric motor. Electric powertrains, in fact, can operate both forward and backward, in both directions. When you press the accelerator pedal, the electric motor starts and moves the wheels, pushing the machine forward. On the other hand, when you press the brake pedal, the movement of the electric engine is opposite, a reverse operation that allows you to generate electricity and recharge the car battery. This system works best with gentle braking, for example when driving the car in the city with continuous but not intense acceleration and deceleration. However, many electric and hybrid vehicles have technologies that help drivers take full advantage of this process by showing when regenerative braking is most effective.
Which cars use regenerative braking?
In addition to the electric car, regenerative braking is also used by hybrid cars, both by plug-in hybrid models with externally rechargeable battery, and by mild and full hybrid cars in which the battery is just recharged by the internal combustion engine, or by regenerative braking. . In combustion cars, however, this mechanism is not present. Obviously, the braking energy recovery system is not the same for all electric and hybrid cars, which have more or less advanced technologies depending on the model. In some vehicles, for example, it is possible to select the intensity of regenerative braking, to choose whether to prefer a sportier or more efficient drive. Regenerative braking, in fact, when it comes into operation involves a slight reduction in the car's performance, with the vehicle being a little less responsive and snappy. For this reason, in some hybrid and electric cars there are different modes of intervention of this system, in this way the driver can adapt its activity according to the different driving circumstances.
The benefits of regenerative braking
Electric and hybrid cars offer numerous advantages, from the possibility of taking advantage of purchase incentives to saving on car insurance through products such as quixa E-Green, the RCA policy discounted up to 20% for electric and hybrid cars. However, one problem with these vehicles is limited range, despite recent advances made by car manufacturers. The new accumulators offer performances that are ever closer to those of endothermic cars, both in terms of distance with a recharge and in terms of the charging speed of lithium batteries. At the same time, technologies such as regenerative braking make it possible to optimize the performance of eco-friendly cars to improve the range and efficiency of zero- and low-emission cars. In stop & go driving conditions, i.e. urban driving, regenerative braking can improve the vehicle's energy efficiency by 20 to 50%. Furthermore, precious energy is not wasted which reduces the environmental impact of mobility, making green cars even more ecological than endothermic cars. The presence of the braking energy recovery system also favors the adoption of greener driving styles, as motorists are more likely to take advantage of this process and maximize vehicle efficiency. It is also necessary to consider the savings on the cost of refills, an economic benefit that can be considerable in a year depending on the kilometers traveled.
The disadvantages of regenerative braking
In some circumstances the regenerative braking of electric and hybrid cars does not work, or does not offer particular advantages. This happens for example when the battery is 100% charged, therefore it is not possible to further recharge the accumulators and the system does not start working but remains deactivated automatically. Regenerative braking also involves a slight braking of the car when it is active, a small slowdown that you have to get used to in order to manage decelerations well. When the device does not work, this additional braking fails, so the car slows down less downhill and you have to pay attention to this small difference, so as not to be unprepared. Overall, regenerative braking is a useful technology for electric mobility, as it improves the performance of electric and hybrid cars while offering a lower environmental impact. While in hybrid cars this system reduces fuel consumption and CO2 emissions, in electric cars it increases the range and energy efficiency of zero-emission vehicles.