Principle Behind the Working of Regenerative Braking Systems

The popularity of high-tech and environmentally friendly electric vehicles has led to significant advancements in supporting and related technologies. LIDAR sensors, physical sensors, tiny high-resolution cameras, high-power processors, motors, and batteries, are not only being developed for EVs but are now becoming advanced enough to be used in other applications. It is an exciting time for the transport industry as these technologies change our thoughts about transportation.

One innovation that has gained attention concerning hybrid and electric vehicles is "regenerative braking." But what exactly is it, and how regenerative braking works? Let's explore this technology in more detail.

Regenerative Braking: Meaning Explained

Regenerative braking was a groundbreaking concept introduced in 1967 by the American Motors Corporation. The aim was to enhance a vehicle's range by harnessing the energy produced during braking and utilizing it to power its electrical components. However, despite its innovative design, the technology was only widely adopted once hybrid and electric vehicles became more prevalent.

In contemporary times, regenerative braking systems are an integral part of most hybrid and electric cars, making them significantly more efficient and environmentally friendly. 

Regenerative braking is a clever technology designed to save energy usually wasted during braking. In traditional cars, the kinetic energy generated by braking is transformed into heat and lost in the environment, resulting in a significant waste of energy. However, with regenerative braking, the energy generated during braking is captured and converted into electrical energy to recharge the vehicle's batteries.

While electric and hybrid vehicles rely heavily on regenerative braking, they also have a conventional braking system. The braking force is divided between the two systems, with part assigned to the traditional brakes and the rest allocated to energy regeneration. The regenerative braking control unit determines if both systems are necessary for safe driving and decides whether to store or use the regenerated energy.

Regenerative braking isn't limited to hybrid or electric cars; even conventional cars with petrol or diesel engines use the same principle to charge their batteries and save fuel. Additionally, many electric bikes are now equipped with regenerative braking technology.

How Regenerative Braking Works in Electric Vehicles?

The electric motor in hybrid and electric cars is designed to operate in two directions: one to propel the vehicle and the other to recharge the battery. As a driver lifts their foot off the accelerator pedal and onto the brake, the motor switches directions and regenerates energy stored in the battery.

As a result of this process, the car slows down, and the degree of regenerative braking can vary depending on the car's manufacturer. Different cars can have distinct programming to determine how much energy is regenerated when the driver releases the pedal.

It is important to note that all hybrid and electric cars still have traditional brakes. If the driver presses the brake pedal firmly enough, the hydraulic system will activate, enabling the vehicle to stop quickly, depending on the speed. However, the force required on the pedal to activate the brakes can vary between car models.

When Is Regenerative Braking Activated?

Regenerative braking is a technology that recovers energy otherwise wasted during the braking process in two conditions: when the driver applies the brake, the electric vehicle decelerates, and when the driver ends accelerating, the electric vehicle begins coasting. This technology uses a reverse flow of electricity to recharge the battery.

The latest regenerative braking systems may recover a maximum of 70% of the kinetic energy generated during braking, making it a highly efficient technology. The electricity generated during regenerative braking is directly proportional to the braking force applied. Thus, a more robust braking force generates more significant regenerative braking energy.

Moreover, the amount of regenerative braking energy recovered depends on the vehicle's speed and the duration of braking. The faster the vehicle is moving, the more energy is generated. Similarly, the longer the braking time, the more energy can be recovered.

Does Regenerative Braking Feel Different?

The transition point between the regenerative and conventional braking systems can take some time to identify, so the driver may need to step harder on the pedal to stop the vehicle quickly.

Fortunately, modern vehicles now have various options that allow drivers to customize the feel of regenerative braking. It provides the flexibility to determine the level of regenerative braking if you want to recharge your batteries as much as possible. If you're not familiar with the car slowing down by itself, you can also disable regenerative braking entirely.

Moreover, some car manufacturers now offer a "one-pedal driving" feature, which lets you control the accelerator pedal instead of constantly switching between the brake and accelerator pedals. This feature is available on several electric vehicles, such as the Tesla Model S Performance, Nissan Leaf, and Jaguar I-Pace, and it's also known as the E-pedal. With one-pedal driving, one can easily regulate the vehicle's speed and bring it to a stop without having to press the brake pedal.

Advantages of Regenerative Braking

Regenerative braking offers numerous advantages, making it an increasingly popular technology in the automotive industry. Some of them are listed below:

• Better Fuel Efficiency for Hybrids

Hybrid vehicles are designed to maximize the use of electric motors and reduce reliance on their internal combustion engine. Regenerative braking plays a critical role in this design by helping to keep the battery pack charged, thereby minimizing the need for the engine to power the vehicle. It reduces fuel consumption and saves drivers money on fuel costs.

• Prolongs the Battery Charge

After capturing the energy from regenerative braking, the system converts it into electrical energy and stores it in the vehicle's battery pack. This stored energy can then be used to power the electric motor or other electrical components in the vehicle, which helps to prolong the battery's charge and extend the range of the vehicle.

• Reduces the Wear and Tear on the Vehicle’s Braking System

One of the critical advantages of regenerative braking is that it helps to reduce the wear and tear on the vehicle's brakes, especially in electric and hybrid vehicles where regenerative braking is used in combination with friction brakes. With traditional friction brakes, the moving vehicle's kinetic energy is converted into heat through the friction between the brake pads and the rotor. This process can generate heat, leading to brake fade and wear over time. In contrast, regenerative braking uses the electric motor to slow down the vehicle, reducing the dependency on friction brakes and the associated wear and tear.

Conclusion

Thus, this was all about the regenerative braking system working principle. If you are an aspiring automotive engineer interested in gaining hands-on experience with regenerative braking technology, there are several real-world projects you can undertake to enhance your skills and boost your resume.

Skill-Lync is an online learning platform that offers a variety of courses and projects focused on automotive engineering, including projects related to regenerative braking. Our PG Program in Electric Vehicle Design and Development will equip you with the right skill sets and make you eligible for a lucrative career. Talk to our experts to get your free demo.