Patent ID: 7852047

Claim:
A disconnection detection device for detecting disconnection of at least a portion of an assembled battery in an assembled battery system, the disconnection detection device comprising: a plurality of secondary battery cells serially connected to form the assembled battery; and a plurality of monitoring circuits, ones of which are connected in parallel to respective ones of the plurality of secondary battery cells, each of the plurality of monitoring circuits configured to monitor a charge/discharge state of a corresponding one of the plurality of secondary battery cells, the each of the plurality of monitoring cells including: current supplying means for supplying a detection current; current route changing means for changing a route in which the detection current flows; and disconnection detecting means, wherein, when a disconnection occurs: the current supplying means supplies the detection current larger than a consumption current flowing via the monitoring circuit at a normal state to a connection line between the cell and the monitoring circuit; the current route changing means changes the route in which the detection current flows so as to generate a reversal of an electric potential relation between a positive-side and a negative-side of the corresponding one of the plurality of secondary battery cells; and the disconnection detecting means detects the reversal of the electric potential relation and outputs a disconnection detection signal.