NOVELTY - The device (42) has a casing (18) for locking a traction battery (16) in a water-tight manner, and a ventilator (44) arranged inside the casing for regulating circulation of a gas coolant (G) i.e. refrigerant, inside the casing to control temperature of the battery. A cooling unit (46) and a heating unit i.e. electrical resistor (48), control temperature of the coolant. The cooling unit comprises a heat exchanger (52), and an air conditioning evaporator (28) supplies the coolant to the heat exchanger and comprises a compressor (32) and a condenser (36) that is arranged outside the casing.    USE - Device for controlling temperature of an electricity storage device i.e. electrical traction battery, of a vehicle i.e. car (all claimed).    ADVANTAGE - The casing locks the traction battery in a water-tight manner, thus preventing leakage of corrosive fluids contained in the batteries during accident of the vehicle. The gas coolant is circulated inside a closed-loop, thus controlling moisture and purity of the coolant in an easy manner. The ventilator is arranged inside the casing for regulating circulation of the gas coolant inside the casing to control the temperature of the battery, thus maintaining the battery at optimal temperature of about 10-30 degree Celsius during operation of the vehicle. The device is designed such that requirement of a free space for conveying fresh air inside the casing is avoided, so that the device has a compact structure. The device enables protection of components from exposure to moisture or polluting particles coming from outdoor air.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a vehicle.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a traction battery of a vehicle provided with a device for controlling temperature of the traction battery.    Gas coolant (G)    Traction battery (16)    Casing (18)    Air conditioning evaporator (28)    Compressor (32)    Condenser (36)    Device for controlling temperature of electricity storage device (42)    Ventilator (44)    Cooling unit (46)    Electrical resistor (48)    Heat exchanger (52)