In today’s complex, capitalistic world, having an abundance of things sounds unrealistic to most of the population regardless of the region in which they live. From gaining material wealth to taking care of mental health, people have had to struggle on a daily basis. Therefore, as much as gaining things, it’s really important to try to save/recycle things that are in our possession. The reduction of the waste of resources is vital to the survival of the planet and every individual who inhabits it. Regenerative braking aka regen is an energy recovery mechanism that can come in handy in such scenarios.         

 

What is Regenerative Braking?

 

Simply put, regenerative braking can be defined as an energy recovery mechanism that slows down a vehicle/object in motion by converting its kinetic energy or potential energy into some other form of energy. The form of energy that is a result of the conversion can be either used immediately or stored until needed.  An electric motor functioning as an electric generator is the most common form of regen. The application of regenerative braking can be observed very much in the automotive industry including electric railways, battery electric and hybrid electric vehicles, hydraulic hybrid vehicles, and hydrogen fuel cell powered vehicles.

 

Use of regenerative braking in the automobile industry

 

Usually, someone who is a Formula One fan or an electric/hybrid car enthusiast is familiar with the term regenerative braking. Hybrid cars like the Toyota Prius and fully electric cars like the Tesla Roadster primarily use this kind of braking system. In hybrid and electric automobiles, regen converts the kinetic energy which is a result of the car’s momentum into electrical power that can be used to charge the vehicle’s high-voltage battery. It also slows the car down assisting the use of traditional brakes.   

 

In a conventional braking system, when the driver pushes the brake pedal, hydraulic fluid moves the brake pads against the car’s brake discs. Then, the car slows down because of friction between the brake pads and rotors. As a result of this, the kinetic energy that helps propel the car forward becomes heat. In addition to that, this system wears away at the material on the pads and discs in the process. Unfortunately, in a conventional braking system, almost all the heat generated is wasted.

 

Regen is capable of conserving this energy by recapturing up to 70% of this kinetic energy. The amount of energy that can be recovered depends on the car model and the driving style. 

 

How regenerative braking works

 

Being able to run either forward or backward is a special characteristic an electric motor possesses. When the car moves forward, the motor rotates in the same direction. However, when under braking, it can spin in the opposite direction, generating energy. When the driver presses the accelerator pedal, the motor drives the wheels in a forward direction. This results in the car moving forward. As the driver removes their foot from the accelerator, the vehicle’s momentum turns the motor into a generator. This induces a current that’s fed back to the battery.    

 

When the driver puts pressure on the brake pedal, it increases the electrical resistance of the motor. This system slows the car down faster while generating even more current to recharge the battery.

 

The sensation the regenerative braking gives 

 

Many modern cars use regenerative braking systems and when it comes to driving, they all give a different sensation to the driver. Regenerative braking feels like someone is gently applying the brakes right after the driver takes their foot off the accelerator. In the beginning, it might give someone a very odd sensation but a few miles into the journey, it becomes second nature to many drivers. Most electric cars allow the driver to tailor the way they want to feel so the driver can customize the settings based on their preferences.  

 

Many systems allow the driver to alter the aggression level when the regenerative brakes are applied. If someone wants to harvest as much energy as possible, they can set the car’s system to its highest setting. While a system that is set to gentler settings delivers a sensation akin to lifting off the accelerator as someone’s driving uphill, the sensation is more powerful as the settings get fiercer.  

 

In case someone doesn’t like the sensation at all, they have the option to turn off the regen system and let the car coast.   

 

What is one-pedal driving?

 

One-pedal driving technique comes with many plug-in hybrid electric cars and all-electric cars. This provides the automobile with the ability to stop and go using only the accelerator pedal. This functionality is available in a growing number of electrified cars because of the regenerative braking systems. In fact, one-pedal driving is a more extreme form of regen. It is able to stop the car relatively quickly and bring it to a complete stop without someone touching the brake pedal. 

 

The pros and cons of regenerative braking

 

As mentioned earlier, regen is an energy recovery mechanism that contributes towards the efficiency of the vehicle. 

Here are the good aspects of regenerative braking that make it popular among the automobile industry personnel and consumers. 

 

Pros:

 

• Contributing towards the longevity of brake pads and rotors 

 

Despite the stopping force regen systems provide, electric cars and hybrid cars also come with conventional hydraulic brakes. However, since the regenerative system does much of the work when it comes to slowing the vehicle, unlike in automobiles that only have a conventional braking system, braking pads and rotors aren’t used frequently in cars that have a regen system. Therefore, they last longer in between services. As a result of that, the owners/drivers can save on maintenance costs.   

 

• Boosting the battery range for EVs. 

 

As mentioned earlier, regenerative braking captures braking energy and sends it right back to the EV’s battery. Therefore, the driving range of the vehicle increases. According to the estimations, regen is capable of adding hundreds of miles of electric driving range per year. Therefore, the driver can spend less time on charging which leads to fewer worries about the journey. Also, when the battery is plugged into the electric grid less often, it helps reduce emissions from electricity suppliers powered by coal and gas. 

 

• Enhancing the fuel efficiency for hybrids 

 

Despite having internal combustion engines, hybrids are designed to use their electric motor as much as possible. Regen helps recharge the battery pack. Therefore, drivers aren’t required to rely on their engines as often. This helps them reduce fuel consumption and the cost on fuel.

 

Cons:

 

Just like any other technology, regenerative braking systems also have some drawbacks. Here are a few examples.

 

• Can be less effective at lower speeds.

 

A slower speed means less momentum. Less momentum means less kinetic energy. When the vehicle has less kinetic energy, it requires less braking force. Therefore, the regen doesn’t get fed enough energy to supply the battery pack with much charge. According to some automobile manufacturers, coasting may be more beneficial in some scenarios. 

 

• The driver has to get used to different sensations in the beginning because the conventional braking system doesn’t come with the same experience. 

 

• Potentially lower stopping power

 

Regen systems perform well in most scenarios where the car gradually comes to a stop. However, still, it may not provide the same level of stopping force the conventional brakes do. Therefore, compared to conventional vehicles, hybrid/ EV drivers have to put more pressure on the pedal to achieve the same level of braking power. 

 

However, in more recent car models, this problem has been mostly taken care of and one may not even notice a difference between conventional braking systems and regen systems. 

 

There are several regen systems but all of them do a similar job. Only the methods that are used to vary the braking force differ from each other. In a time that requires most of the population to hustle and save every penny while being mindful of the impact their actions might have on nature, an energy-recapturing mechanism like regenerative braking gives hope and relief to a certain extent. With the advancement of technology, the evolution of regen systems would be a blessing to people. The ease and comfort it brings to both the driver and the environment will continue to revolutionize the automobile industry. 

 

References and further reading

 

www.whatcar.com. (n.d.). What is regenerative braking and how does it work? [online] Available at: https://www.whatcar.com/news/what-is-regenerative-braking-and-how-does-it-work/n25212.

 

Tires Plus (2022). Regenerative Braking: Advantages, Disadvantages, & How It Works | Tires Plus. [online] www.tiresplus.com. Available at: https://www.tiresplus.com/blog/brakes/what-is-regenerative-braking-in-electric-vehicles/.

 

Naylor, S. (2020). Regenerative braking: what is it and how does it work? [online] Auto Express. Available at: https://www.autoexpress.co.uk/tips-advice/353643/regenerative-braking-what-it-and-how-does-it-work.

 

J.D. Power. (n.d.). What is One-Pedal Driving and How Does it Work? [online] Available at: https://www.jdpower.com/cars/shopping-guides/what-is-one-pedal-driving-and-how-does-it-work.

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Lampton, C. (2009). How Regenerative Braking Works. [online] HowStuffWorks. Available at: https://auto.howstuffworks.com/auto-parts/brakes/brake-types/regenerative-braking.htm.

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