NOVELTY - The temperature control apparatus has a baffle which is connected to an actuator and is driven by the actuator to close or open an air vent (311). A temperature sensor is mounted to a battery module (300) to measure the temperature of the battery module. A controller is configured to calculate a temperature deviation by identifying a maximum temperature battery module and a minimum temperature battery module based on the temperature measured with the temperature sensor. The controller operates the driving mechanism based on the calculated temperature deviation.    USE - Temperature control apparatus for battery system for vehicle, e.g., electric vehicle or hybrid electrical vehicle.    ADVANTAGE - Allows the temperature equilibrium of the battery to be reached efficiently with a simpler structure in a decreased time period by checking the temperature deviation between battery modules. Lowers the temperature of the maximum temperature battery modules and maintains the heat equilibrium inside the battery by allowing sufficient amount of cooling air to flow into the battery by raising the stage of the cooling fan to cool the battery to a predetermined level by predetermined stages. Protects the battery from being deteriorated and enhances the durability of the entire battery by lowering the temperature of the maximum temperature battery modules and maintaining the heat equilibrium inside the battery. Extends the battery life by reducing the temperature deviation between battery modules inside a battery and prevent deterioration and the durability deviation in advance between battery cells.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following:    (1) a temperature control method of the battery system for vehicle; and    (2) a non-transitory computer readable medium containing program instructions executed by a controller.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of the battery module.    Battery module (300)    Housing (310)    Air vent (311)    Battery cells (330)