Battery Pack, Battery Apparatus and Method for Detecting Electrolyte Leakage

In a battery pack, a battery monitoring circuit is connected to a battery module including a plurality of battery cells to monitor the battery module. The detection sensor detects an electrolyte leaking in the battery module, and includes a first resistor and a second resistor connected in series between a power supply supplying a first voltage and a ground terminal, and a variable resistor connected to the first resistor in parallel and having a resistance that varies depending on the electrolyte leaking in the battery module. The detection sensor transfers, as a sensing voltage, a voltage at a contact between the first resistor and the second resistor to an input terminal of the battery monitoring circuit.