I'm making a device that will operate in cold environment. The ambient temperature will vary between -50℃ and -20℃. The sensor is supposed to monitor the temperature so that the microcontroller in my device decides, whether a battery heating system in the device runs or not. The temperature could change at a speed of 0.2℃/s.
What would be the best sensor type among a digital temperature sensor (like DS18B20), a RTD, and a thermocouple?