Battery pack

A battery pack comprising:

• a first switch connected between a first end of a battery and a first output terminal;
• a second switch comprising:
• a first terminal and a second terminal, which are connected to a second end of the battery;
• a third terminal and a fourth terminal, which are connected to a second output terminal;
• a plurality of fixed contacts corresponding to each of the first terminal, the second terminal, the third terminal, and the fourth terminal;
• a movable contact configured to electrically connect the first terminal and the third terminal, or to electrically connect the second terminal and the fourth terminal;
• and
• an electromagnet configured to control the movable contact according to whether a current is applied or not;
• a pre-charge resistor connected between the third terminal of the second switch and the second output terminal;
• and
• a controller configured to control the second switch such that the second switch is turned on if a precharging period of time elapses after the first switch is turned on,
• wherein the first terminal and the third terminal are electrically connected when the second switch is turned off, and wherein the second terminal and the fourth terminal are electrically connected when the second switch is turned on.