Battery warm-up apparatus and method thereof

A the battery warm-up apparatus includes an electric motor (2), a battery (4), an electric generator (6) for charging the battery, an engine (7) for driving the electric generator, a refrigeration circuit (8a) arranged to pass through inside the engine in a manner that a temperature medium flows through an inside thereof, a heat exchanger (9), a battery-heating channel (8b) branched from the refrigeration circuit, arranged to pass through the battery and connected to the refrigeration circuit again, a first switching valve (13) arranged at a first portion of the refrigeration circuit, the battery-heating channel being branched from the refrigeration circuit at the first portion, the first switching valve connecting and disconnecting the battery-heating channel relative to the refrigeratiort circuit, a battery temperature sensor (4a), and a controller (15) for operating the first switching valve on the basis of temperature (T B ) of the battery and for allowing the temperature medium to flow through the battery-heating channel.