Bimetal temperature controller
The automatic power-off function of an automatic electric kettle is generally realized by a bimetallic thermostat located at the upper part of the water cup and inside the handle (or at the bottom of the cup, which requires a long air duct). There is no relay or thermistor inside, and it feels the temperature of steam released by water, so it is indirect. Generally, only after the water boils can the steam temperature reach the disconnection point of the thermostat.
Will not automatically cut off the power.
If you open the lid to boil water, it won't automatically disconnect.
Anti-dry burning component
The temperature control and anti-dry burning parts of automatic electric kettle are patented products of a British company, which contain many precise details and know-how.
Will not automatically reheat.
After the water is boiled, it will not be automatically reheated (thermistor can't do it) because there is another linkage mechanism.