FAULT DIAGNOSIS APPARATUS FOR SWITCHING DEVICES, BATTERY PACK, FAULT DIAGNOSIS PROGRAM FOR SWITCHING DEVICES, AND METHOD OF FAULT DIAGNOSIS FOR SWITCHING DEVICES

摘要

PURPOSE: A switch failure diagnosis device, a battery pack, a switch failure diagnosis program, and a switch failure diagnosis method thereof are provided to diagnose the off prohibition failure of a switch element during a charging or a discharging process. CONSTITUTION: A switch failure diagnosis device (3) comprises a parasitic diode (D1) and a field effect transistor (FET) (31) for blocking a charger. The FET is installed in a current path in which the charging current and discharging current of a secondary battery (2) is conducted. The parasitic diode is connected to the FET in parallel and changes the direction of the current. The switch failure diagnosis device gives an off command signal to the FET when the secondary battery is determined as a discharge state. When voltages between the input and the output of the FET are smaller than a first reference value, the switch failure diagnosis device determines off failure. [Reference numerals] (34B) Memory; (35) First voltage detection circuit; (36) Second voltage detection circuit; (5) Charger; (6) Load