Mercedes Reinvents Brakes For EVs, Puts Them Inside The Drive Unit

The manufacturer says in-drive brakes could provide a lifetime braking solution for electric vehicles with multiple advantages.

Mercedes Future Experience

Photo by: Mercedes-Benz

Andrei Nedelea

By: Andrei Nedelea

Nov 22, 2024 at 6:01pm ET

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Mercedes has developed a new in-drive braking system touted as having several significant advantages.
It is "virtually maintenance-free," traps brake dust, is better for the environment and promises to eliminate brake fade.
The system is currently being tested with no clear time frame for a production application.

The vast majority of cars have outboard brakes that are connected to their wheel hubs, and only a handful come with inboard brakes. Mercedes has taken things one step further and put the brakes inside the housing of an electric vehicle’s drive unit, and it’s touting multiple advantages, including never having to service the brakes for the lifetime of the car.

Electric vehicles can use their motors to slow down, not only saving their friction brakes from wear but also putting electricity into their battery pack. Various companies have proposed different types of brakes for EVs, from Continental’s ultra-thick mountain bike-like disks to the drum brakes that Volkswagen equips all vehicles built on its MEB platform, like the ID.4 or Audi Q4 E-Tron.

VW argues that even in its EVs with over 300 horsepower, drum brakes are sufficient for the rear. Most of the braking is done by the front brakes anyway, so going back to this older style of brakes (which is cheaper than disk brakes) is one way VW has adapted its vehicles for electric propulsion.

Mercedes has now taken this one step further with its in-drive brakes. However, it hasn’t simply taken a traditional disk or drum brake setup and put it inside the drive unit. It completely reimagined braking, and in the version of the system they showed us in Stuttgart last week, the disk is water-cooled and it doesn’t spin, and the brake pad is circular and it spins with the motor.

There is no traditional caliper either and scrubbing speed is achieved by pushing the circular brake pad onto the stationary disk. Mercedes says this system shouldn’t require service for the lifetime of the vehicle and all the brake dust it generates is kept inside the system in a compartment that doesn’t need to be emptied.

The upcoming Euro 7 (EU7) emissions standard doesn’t just look at tailpipe emissions. It also takes tire and brake particulate emissions from vehicles into account, so keeping brake dust from going into the environment will become more of a talking point in Europe once EU7 comes into force in 2026.