Battery self-heating control method, battery self-heating device, battery self-heating system and vehicle

The invention relates to a battery self-heating control method, a battery self-heating device, a battery self-heating system and a vehicle, and the method comprises the steps: obtaining a temperature detection value and a charging and discharging current value of a battery cell at a time point through a temperature sensor and a current sensor at the time point after the battery self-heating process starts; determining a temperature estimation value of the battery cell at a target time point according to the charge-discharge current value, the rated capacity of the target battery and the internal resistance of the battery cell; and comparing the difference value of every two of the temperature target value, the temperature detection value and the temperature estimation value corresponding to the battery with a plurality of preset temperature thresholds to determine whether the temperature of the target battery is abnormal at the time point, and further to determine whether to stop the self-heating process of t