Battery pack and data transmission method of battery pack

A data transmission method for a battery pack including a battery, the data transmission method comprising:

• at a controller, checking a state of the battery and generating a battery state signal corresponding to the state of the battery;
• and
• making or breaking, at a switch circuit, electrical connection between a resistor circuit and a reference node based on the battery state signal,
• wherein the resistor circuit comprises a plurality of resistors, and
• wherein the switch circuit comprises a plurality of switches configured to respectively make or break electrical connection between the reference node and the resistors.

A battery pack comprising:

• a battery comprising at least one battery cell;
• a controller configured to check a state of the battery and generate a battery state signal corresponding to the state of the battery;
• a switch circuit configured to operate based on the battery state signal;
• a resistor circuit configured to be electrically connected to a reference node through the switch circuit;
• and
• a connector configured to connect the resistor circuit to an external device having no switch circuit therein.