Battery Pack

A battery pack, comprising:

• a first battery contactor, wherein a first end of the first battery connector is configured to be electrically connected to a positive electrode terminal of a battery;
• a second battery contactor, wherein a first end of the second battery connector is configured to be electrically connected to negative electrode terminal of the battery;
• a first charging contactor, wherein a first end of the first charging contactor is electrically connected to a second end of the first battery contactor;
• a second charging contactor, wherein a first end of the first charging contactor is electrically connected to a second end of the second battery contactor;
• a first measurement resistor electrically connected between a first node located at the first end of the second charging contactor and a second node located at the first end of the first charging contactor;
• a second measurement resistor electrically connected between the first node and a third node located at a second end of the first charging contactor;
• a third measurement resistor electrically connected between the first node and a fourth node located at a second end of the second charging contactor;
• a first power connector having:
• a first input terminal electrically connected to the second end of the first charging contactor;
• and
• a second input terminal electrically connected to the second end of the second charging contactor;
• and
• a control unit configured to, when first and second output terminals of a second power connector of a charger are electrically connected to the first input terminal and the second input terminal of the first power connector, respectively, and a charging voltage is being applied from a power source of the charger to the battery pack between the first output terminal and the second output terminal;
• control at least one of the first charging contactor or the second charging contactor to change from a turn-on state to a turn-off state;
• and
• 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 measured across the first measurement resistor, a second measured voltage measured across the second measurement resistor or a third measured voltage measured across the third measurement resistor.