One of the first things people notice in an electric car is how quietly it slows down. There is no engine noise, and often no brake sound at all. Here is why EV brakes are so quiet.
Regen makes no friction noise
Most of an EV's slowing comes from regenerative braking, which works by turning the motor into a generator - see how regen braking works. There are no pads scraping a rotor during regen, so the slowing is essentially silent, unlike friction braking that can squeak or groan.
The friction brakes are barely used
Because the friction pads only engage for harder stops - see do EVs have brake pads - they simply are not making noise most of the time. Less use also means less of the glazing and wear that cause squeal on gas cars; see why brakes squeak.
No engine to mask or make sound
An EV has no engine noise, so on the rare occasion the friction brakes do make a sound, it can be more noticeable simply because the car is otherwise silent. A little rust squeal on the first morning stop stands out more than it would in a gas car.
Keeping them quiet
Quiet EV brakes can still rust from disuse, which causes noise until scrubbed off; see rotor rust prevention. Occasional firm braking helps. When pads finally wear, fit quality pads and hardware.