NOVELTY - The battery pack (100) comprises battery cells (10a,10b) arranged parallel to each other, a PCM (40) adjacent to one of the battery cells, and a temperature measuring unit (30) attached to the PCM and extending between, and in contact with, two battery cells to measure the temperature of the battery cells.    USE - Battery pack used for portable electronic device. Can also be used for medium and large sized apparatus, such as machine tool, electric bicycle, and automobile.    ADVANTAGE - Improves temperature control capability of battery cells by using a new temperature measuring unit. The PCM extends the lifetime of the battery cell in charging/discharging of the battery cell and prevents the battery cell from being short-circuited by a charger or external terminal. The head portion of the temperature measuring unit is safely mounted in a space provided between the battery cells so as to prevent damage of the head portion. Material cost and processing cost are reduced since silicon used for temperature measuring unit and silicon dispenser are omitted. The temperature measuring unit is removably fixed to the battery cell without using a separate member, thus, temperature of battery cell is exactly measured, and safety of battery pack is improved and failure rate caused by e.g. lift-off phenomenon is reduced. The temperature measuring unit is formed into a ring shape so as to surround the first battery cell after being inserted between the first and second battery cells, thus, the temperature measuring unit is firmly fixed to the first battery cell without being moved by external force such as drop or vibration. Prevents up-and-down movements of the temperature measuring unit, and prevents the temperature measuring unit from coming off the battery cells.    DESCRIPTION OF DRAWING(S) - The drawing shows the perspective view of the battery pack.    Battery cells (10a,10b)    Electrode lead (20)    Temperature measuring unit (30)    Protection circuit module (40)    Battery pack (100)