Patent ID: 7535199
Filing Date: 2009-05-19
Classification: H02J

Abstract:
1. A battery pack, comprising: a battery set which includes a plurality of series modules connected in parallel having a plurality of secondary-battery cells connected in series, each of the secondary-battery cells forming each series module being connected in parallel; and a battery-abnormality detection circuit which detects an abnormal state in the battery set, wherein: the battery set further includes, a plurality of parallel-connection separation switches which electrically separate the secondary-battery cells connected in parallel, and a plurality of battery-set circuit separation switches which separate the series modules having the secondary-battery cells separated by the parallel-connection separation switches from a battery-set body connected to an external circuit; the battery-abnormality detection circuit further includes a detection-circuit changing switch which changes the connection state to the battery set, so as to detect the voltage of the secondary-battery cells connected in parallel when the parallel-connection separation switch is turned on and so as to detect the voltage of each secondary-battery cell whose parallel connection is separated when the parallel-connection separation switch is turned off; and the battery-abnormality detection circuit controls the battery-set circuit separation switch, so as to detect an abnormal state in each secondary-battery cell, based on a change in the voltage of each secondary-battery cell whose parallel connection is separated when the parallel-connection separation switch is turned off and so as to separate, from the battery-set body, the series module including the secondary-battery cell whose abnormal state is detected.