| 摘要 |
PROBLEM TO BE SOLVED: To provide a protective device for a secondary cell capable of preventing a switching device from having thermal destruction due to the passage of a heavy current by conducting an overcurrent protection at the time of not only discharging but also charging. SOLUTION: This secondary cell, constructed by serially connecting a plurality of battery cell blocks 1A, 1B, and serially providing a charging FET 4 and a charging FET 4 and a discharging FET 5 composed of FETs with parasitic diodes as a switching device capable of an on/off control with a control circuit 6 in a charging/discharging path, is formed with charging and discharging current detecting means 7, 8. The control circuit 6 is provided with a means of controlling the FETs 4, 5 to prevent the generation of charging and discharging of detecting an overcurrent, where a charging current or discharging current exceeds a prescribed level. |
