| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a small protective device for a secondary battery having high energy density by installing at least a single battery protective circuit element to cut off an electric current by detecting at least one kind of abnormality of overcharge, overdischarge, an overcurrent and temperature abnormality, on a plate-like lead of a positive characteristic temperature element. SOLUTION: In an ordinary condition, heat by current-carrying of a battery protective circuit element 5 is radiated by lead parts 3 and 4 thermally joined to a heat radiating plate 9. When an excessive electric current flows by a short circuit, a carrying electric current is restrained by an increase in resistance of this element by heating of a positive characteristic temperature element 2. A temperature of the positive characteristic temperature element 2 is also detected by a temperature detecting element 10, and when the temperature exceeds a prescribed value, current-carrying can also be cut off by operating an electric current cutoff circuit in the battery protective circuit element 5. Therefore, a battery can be protected with high reliability by a double safety device such as cutoff of current-carrying by an increase in resistance of the positive characteristic temperature element 2 and operation of the electric current cutoff circuit of the battery protective circuit element 5.</p> |
