A battery pack, comprising: a first battery contactor and a second battery contactor respectively having one end electrically connected to a positive electrode terminal (+) and a negative electrode terminal (-) of a battery; a first charging contactor and a second charging contactor respectively having one end electrically connected to the other end of the first battery contactor and the other end of the second battery contactor; a first measurement resistor, a second measurement resistor and a third measurement resistor, the first measurement resistor is electrically connected between a first node located at one end of the second charging contactor that is connected to the other end of the second battery contactor and a second node located at one end of the first charging contactor that is connected to the other end of the first battery contactor, the second measurement resistor is between the first node and a third node located at the other end of the first charging contactor, and the third measurement resistor is between the first node and a fourth node located at the other end of the second charging contactor, respectively; a first power connector having a first input terminal and a second input terminal electrically connected to the other end of the first charging contactor and the other end of the second charging contactor, respectively; and a control unit configured to, when a second power connector of a charger having a first output terminal and a second output terminal respectively electrically connected to the first input terminal and the second input terminal is connected to the first power connector and charging is being performed, diagnose a fault of each of the first charging contactor and the second charging contactor based on at least one of a first measured voltage, a second measured voltage and a third measured voltage applied to the first measurement resistor, the second measurement resistor and the third measurement resistor, respectively, wherein the control unit is configured to diagnose a turn-on fault of the first charging contactor based on a measured voltage difference between the first measured voltage and the second measured voltage, and wherein the control unit is configured to diagnose a turn-on fault of the second charging contactor based on the third measured voltage. a first battery contactor and a second battery contactor respectively having one end electrically connected to a positive electrode terminal (+) and a negative electrode terminal (-) of a battery; a first charging contactor and a second charging contactor respectively having one end electrically connected to the other end of the first battery contactor and the other end of the second battery contactor; a first measurement resistor, a second measurement resistor and a third measurement resistor, the first measurement resistor is electrically connected between a first node located at one end of the second charging contactor that is connected to the other end of the second battery contactor and a second node located at one end of the first charging contactor that is connected to the other end of the first battery contactor, the second measurement resistor is between the first node and a third node located at the other end of the first charging contactor, and the third measurement resistor is between the first node and a fourth node located at the other end of the second charging contactor, respectively; a first power connector having a first input terminal and a second input terminal electrically connected to the other end of the first charging contactor and the other end of the second charging contactor, respectively; and a control unit configured to, when a second power connector of a charger having a first output terminal and a second output terminal respectively electrically connected to the first input terminal and the second input terminal is connected to the first power connector and charging is being performed, diagnose a fault of each of the first charging contactor and the second charging contactor based on at least one of a first measured voltage, a second measured voltage and a third measured voltage applied to the first measurement resistor, the second measurement resistor and the third measurement resistor, respectively, wherein the control unit is configured to diagnose a turn-on fault of the first charging contactor based on a measured voltage difference between the first measured voltage and the second measured voltage, and wherein the control unit is configured to diagnose a turn-on fault of the second charging contactor based on the third measured voltage.