NOVELTY - A battery overheating protection device (300) comprises temperature monitoring unit (310) for storing predetermined temperature value, measuring temperature value of battery unit, and outputting signal when detected temperature value is greater than predetermined temperature value; switch unit (330) connected between main unit (100) and battery unit (200); and processing unit (320) for receiving signal and opening switch unit when receiving signal to disconnect battery unit from main unit.    USE - A battery overheating protection device used in electronic device including cellular phone or portable gaming device (claimed).    ADVANTAGE - The temperature value of each battery is measurable independently and accurately. The thermistor is protected and can still function normally even if one of thermistor cells is damaged. When overheating, the battery unit becomes inactive and cools down, thus protecting battery unit from damage.    DETAILED DESCRIPTION - A battery overheating protection device (300) comprises temperature monitoring unit (310) for storing predetermined temperature value, measuring temperature value of battery unit, and outputting signal when detected temperature value is greater than predetermined temperature value; switch unit (330) connected between main unit (100) and battery unit (200); and processing unit (320) for receiving signal and opening switch unit when receiving signal to disconnect battery unit from main unit. The battery overheating protection device is used in electronic device (10) comprising main unit for implementing basic functions of electronic device and battery unit for supplying power to main unit. The temperature monitoring unit comprises thermistor(s) thermally connected to battery unit. Each thermistor cell comprises thermistor body, two electrodes and base, where base is made from glass-ceramic material. The thermistor has housing which is made from organic polymer plastic. An INDEPENDENT CLAIM is included for an electronic device.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of an electronic device including battery overheating protection device including temperature monitoring unit.    Electronic device (10)    Main unit (100)    Battery unit (200)    Battery overheating protection device (300)    Temperature monitoring unit (310)    Processing unit (320)    Switch unit (330)