Hybrid 101: Whenever the car is slowing, foot off the "gas" pedal or braking, the motor is recharging the traction battery. This is called regeneration as it is converting momentum (potential) energy to electricity. This resistance to forward momentum slows the car, just as when the current flow the other direction causes a speed increase. It is common to call this regen braking and as it is not anywhere close to being 100% efficient, it does create heat.
Regen is strong enough to stop the car and the EV versions does just that. Mechanical brakes are mostly used for fast or panic stopping where the driver input for deceleration exceeds what the motor can do, and for the last few inches of a slow full stop. Mechanical brakes on well designed hybrids tend to far outlast conventional cars by some multiple.
2018 Kia LX HEV Metal Stream with Advanced Tech