> The most mechanical innovation we saw was a new type of brake for EVs. Although Mercedes says that EVs typically use regenerative braking for 98 percent of their decelerations, they still need friction brakes for that last 2 percent—which tend to be critical needs. The reason is simple: typical EV regen can provide a maximum of 290 kW of braking power, while a maximum 1G plus stop might require 2200 kW.

>But because these friction brakes are not used much, their rotors tend to rust, leading to noise during application, as well as degraded appearance. And they still produce brake dust.

>To solve these problems, Mercedes is developing what it calls In-Drive Brakes. The idea is to move the brakes from the wheels to inside the electric drive motor at either end, where the half-shafts emerge. The prototype is shown on the rear axle, but the concept could work at both ends.

>The brake would not be a conventional disc brake but rather something that looks like the clutch in a manual transmission. There would be a disc that spun with the half-shaft connected to each wheel. This disc would have friction material on most of each side near the periphery and with something that looked like a non-rotating flywheel on each side. An annular hydraulic cylinder would press the assembly together causing the rotating friction disc to drag on the two fixed plates to slow the car.

> Since this assembly would be fully enclosed in a housing at each end of the motor housing, the two fixed plates would have liquid cooling passages to remove the heat generated by the braking. A small sump at the base of each brake housing would serve to collect the brake dust generated.
mercedes benz innovations future technologies 2024, in drive brake
Mercedes-Benz

> The goal would be for these brakes to last for the life of the car. Being enclosed, they would be quiet. And being inboard, they would leave the wheels clean, reduce unsprung weight, and allow greater freedom for wheel designers, who would no longer have to worry about getting cooling air into the brakes.

This is NOT an innovation.
The initial mentioned problem of brake discs possibly rusting because they are rarely used can be easily address by the car computer periodically using the disc brakes rather than regenerative brakes if those haven't been used recently. Applying the disc brakes a few times every couple of days should not impact the range measurably.

They are making an easily reparable wear item such as brakes, almost cost prohibitive (labor costs) to replace by putting it inside depths of the electric drive unit. You now have to disable and disconnect high voltage battery , pullout the electric motor (usually include the motor, differential gear units, inverters in the same unit so it is similar to pulling out an engine in a ICE car), then take apart that engine, replace the friction clutches used for breaking, and then reverse the whole process to put it all back together.

The only thing this is designed to do is to sell more cars every x years by making cars harder to repair. The funny sad thing is; this is clear anti-consumer activity ironically developed with consumers (tax payers) money using tax write-off for R&D.

This type of thing is also why electric cars have a bad reputation at the moment. They depreciate so fast because the the greedy companies design them to make it impossible to repair economically, and insurance companies write them off after the tiniest accident/issue.