Rapid low-temperature self-heating method and device for battery

A device for implementing a rapid, low-temperature self-healing method for a battery, comprising a low-temperature heating control unit, a short-circuit trigger device, a main control switch K1, an external heating control switch K2, and an external heater, wherein

• the low-temperature heating control unit is connected to a control end of the short-circuit trigger device, and the low-temperature heating control unit controls the main control switch K1 and the external heating control switch K2;
• and the main control switch K1 is connected between a positive electrode of the battery and a DC/DC converter;
• the external heater is arranged on a surface of the battery, one end of the external heater is connected to the positive electrode of the battery, and an other end thereof is connected to the external heating control switch K2;
• one end of the external heating control swatch K2 is connected to a negative electrode of the battery, and an other end thereof is connected to the external heater;
• and
• two ends of the short-circuit trigger device are respectively connected to the positive electrode and the negative electrode of the battery, and is in parallel with the external heater;
• wherein a control method of a heating system specifically comprises the following steps:
• triggering a large-current external short-circuit for rapid heating of the battery, recording short-circuit duration and a short-circuit current when the external short-circuit occurs on the battery, and if the short-circuit duration satisfies any one of the following three conditions, terminating the external short-circuit:
• condition 1:
• the short-circuit duration reaches an initially set lossless short-circuit time threshold, wherein the initially set lossless short-circuit time threshold is associated with an initial battery state of charge (SOC);
• condition 2:
• a second current peak appears, and the short-circuit duration reaches a corrected lossless short-circuit time threshold, wherein the corrected lossless short-circuit time threshold is obtained by correcting the initially set lossless short-circuit time threshold on line by using a time at which a second short-circuit current peak of the battery appears;
• and
• condition 3:
• battery temperature is higher than target temperature;
• and
• estimating a predicted temperature rise when the external short-circuit occurs on the battery, and if a sum of initial temperature and the predicted temperature rise is higher than the target temperature, ending the heating, and starting a battery system;
• or
• if the sum of initial temperature and the predicted temperature rise is lower than the target temperature, conducting external heating by using the external short-circuit of the battery and the external heater together, and after the battery temperature is higher than or equal to the target temperature, ending heating, and starting the battery system.