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Regenerative EV Braking System Increases Truck Range, Efficiency

June 24, 2023 by Mike Falter

​​​​​​​British electric truck manufacturer Tevva, in collaboration with Tier 1 automotive supplier ZF, has completed the development of its new regenerative braking system for the 7.5t battery-electric truck. 

Tevva, a manufacturer of electric trucks, has completed the development of a new regenerative braking system using the electronic braking system (EBS) from Tier 1 automotive supplier ZF.

 

Tevva electric truck

Tevva 7.5t electric truck. Image used courtesy of Tevva

 

According to Tevva, the braking system captures four times more energy than traditional compressed air braking systems, preserving battery capacity and extending the range of its electric 7.5t trucks.

The regenerative system intelligently combines traditional friction braking with the vehicle's electric motor to safely slow the vehicle, reducing wear and tear on the mechanical brakes while returning surplus energy to the vehicle's battery.

 

Regenerative Braking

Regenerative braking is when an EV’s electric motor is used to help slow down the vehicle. During regenerative braking, the electric motor is operated in reverse, and the motor’s electromagnetic force is used to counter the forward rotation of the wheels to slow down the vehicle. The motor acts as a generator during regeneration, producing electricity to recharge the battery. 

In addition to extending vehicle range, regenerative braking also has the advantage of reducing wear and tear on the brakes and improving vehicle safety by providing an added layer of redundancy and more precise control of the vehicle’s speed.


Regenerative braking in an EV

Regenerative braking in an EV. Image used courtesy of Delphi Technologies

 

Electronic Braking Systems

The EBS is integral to the operation of Tevva’s regenerative system. It uses sophisticated monitoring, intelligence, and control systems to manage a braking process that blends friction and motor forces to control a vehicle's speed efficiently.

Depending on a system’s design, regenerative braking may begin when the driver releases their foot from the accelerator, slowing down the vehicle and capturing surplus energy. The motor's braking force may be selected or adjusted to slow the vehicle more aggressively or allow it to coast further with less braking force.

 

Electronic braking system for electric trucks

Electronic braking system for electric trucks. Image used courtesy of ZF 

 

The EBS system from ZF employs a range of controls and sensors that monitor and coordinate the vehicle’s braking systems. Speed and steering angle sensors, along with axle modulators, relay key vehicle information to the electronic control unit so the motor (regenerative), in coordination with the mechanical systems (friction), can be used to slow or stop the truck.

With the EBS, a driver’s deceleration request is immediately relayed electronically to all braking components, resulting in a shorter response time and better braking performance.

By using ZF’s intelligent EBS system, Tevva increased the regenerative braking power of its 7.5t model to 180 kW, a notable improvement over their passive-only regen system, which is limited to 40 kW for safety reasons.


EBS braking pedal

EBS braking pedal. Image used courtesy of ZF 

 

Meeting Safety Standards

With Tevva’s system, when the brake pedal in the truck is pushed, the electric motor generates most of the braking force. Conventional friction braking is still needed to fully stop the truck, but the redundancy adds an extra layer of safety, and the regeneration improves driving efficiency. 

To receive safety approvals from ZF for the new braking system, Tevva engineers had to complete a series of strict compliance tests at the ZF test track in Jeversen, Germany, under a range of conditions, gradients, and surface types.