Battery apparatus and battery management system for measuring insulation resistance

A battery management system of a battery unit connectable to an external device and including a battery pack, comprising:

• A first insulation resistance monitoring circuit that includes a first monitoring terminal, and a first resistor connected between a positive terminal of the battery pack and a node, and is arranged to be connected between the positive terminal of the battery pack and a ground terminal of the external device on a first electrical path, wherein the first electrical path extends from the node to a negative terminal of the battery pack and a second electrical path extends from the node to the negative terminal in parallel to the first electrical path;
• A second insulation resistance monitoring circuit that includes a second monitoring terminal, and is arranged to be connected between the ground terminal and a negative terminal of the battery pack on the first electrical path;
• a voltage monitoring circuit that includes a third monitoring terminal, and is connected between the node and the negative terminal of the battery pack on the second electrical path;
• and
• a processor configured to measure a voltage of the battery pack based on a voltage of the third monitoring terminal, and measures a first insulation resistance formed between the positive terminal of the battery pack and the ground terminal and a second insulation resistance formed between the negative terminal of the battery pack and the ground terminal, based on a voltage of the first monitoring terminal and a voltage of the second monitoring terminal.