Battery pack with protective circuit

摘要

A battery pack comprising a secondary battery (3), a battery protection device comprising a circuit board (14) formed with at least a protective circuit to protect secondary battery, a pack case (2) formed in a flat shape for accommodating said secondary battery and the battery protection device; a positive electrode lead (12) and a negative electrode lead (13) leading from said secondary battery; and external input/output terminals (6a,6b,6c) are provided on the pack case, said positive electrode lead and the negative electrode lead being connected via said battery protecting device to said external input/output terminals; wherein electricity generating elements (10) of said secondary battery are accommodated within an external casing (11) which is sealed by welding the peripheral parts of a pair of laminated sheets, the positive electrode lead and the negative electrode lead being led from one weld-sealed side, said battery protection device being arranged on the side of this secondary battery where said positive electrode lead and negative electrode lead are led out.