When an electric vehicle connects to a DC fast charger, what happens under the hood is a constant conversation between two systems: the vehicle's BMS (Battery Management System) and the charger's controller.
Before a single amp starts flowing, the BMS tells the charger the battery's actual condition: temperature, voltage, state of charge, and the maximum power it can accept at that moment. The charger adjusts its output to those parameters, not the other way around.
This communication stays active throughout the entire session, not just at the start. If the battery temperature rises too high, or the state of charge approaches its programmed limit, the BMS can ask the charger to reduce power in real time, and the charger must respond immediately.
This is what makes DC fast charging, despite moving far more energy in far less time than AC charging, just as safe if not safer: it isn't the charger that decides how much energy to deliver, it's the vehicle itself that requests it, within the limits its manufacturer has defined as safe.