Battery pack temperature control method and device

A method for controlling a temperature of a battery pack, the method comprising:

• a battery pack temperature measurement step of measuring a temperature value of the battery pack before charging/discharging;
• an initial heat generating part driving step of controlling a turning-on/off of a heat generating unit switch through a pulse modulation (PWM) signal having a predetermined first duty ratio so that the heat generating unit is intermittently driven when the temperature value of the battery pack, which is measured in the battery pack temperature measurement step, is less than a preset second reference temperature value;
• a heat generating unit duration increasing step of outputting the PWM signal having the first duty ratio in the initial heat generating unit driving step as a PWM signal having a second duty ratio to turn-on/off the heat generating unit switch when the temperature of the battery pack is equal to or greater than the preset second reference temperature value and less than a preset first reference temperature value after the heat generating unit is driven in the initial heat generating unit driving step;
• and a continuous heat generating unit driving step of setting the duty ratio of the PWM signal having the second duty ratio to 100% to continuously turn on the heat generating unit switch so that the heat generating unit is continuously driven when the temperature of the battery pack is equal to or greater than the preset first reference temperature value after the heat generating unit duration increasing step, wherein the second duty ratio is greater than the first duty ratio, and wherein the first duty ratio is set to 30% for −42° C. to −40° C. and 25% for −44° C. to −42°.