Patent ID: 8269460

Claim:
A disconnection detecting device for a battery including battery blocks each constructed by series-connected unit cells, the device being configured to detect a disconnection of an electrical wire that connects a connection point of an adjacently-connected pair of a higher-ordered battery block and a lower-ordered battery block to a ground terminal of a voltage detection unit configured to detect a voltage between both ends of a unit cell belonging to the higher-ordered battery block and to a power supply terminal of a voltage detection unit configured to detect a voltage between both ends of a unit cell belonging to the lower-ordered battery block, the device comprising: a switch element configured to decrease an impedance of the voltage detection unit that detects the voltages between both ends of the unit cells belonging to the higher-ordered battery block; and a disconnection detecting unit configured to detect the disconnection of the electrical wire based on a voltage between both ends of a lowest-ordered unit cell of the higher-ordered battery block, the voltage between both ends being detected by the voltage detection unit while the switch element is turned on.