Patent ID: 8907626

Claim:
A battery pack control apparatus for monitoring a voltage of a plurality of series-connected cells constituting a battery pack, the battery pack control apparatus comprising: a voltage detecting means that detects a voltage of at least one cell in the plurality of cells; a reference voltage generating means that generates a reference voltage; a voltage comparing means that compares the voltage of the at least one cell with the reference voltage; a switching means comprising a plurality of voltage switching circuits that relatively change the reference voltage; and a determining means that: determines a state of the battery pack based on a result of the comparison outputted from the voltage comparing means; and determines whether there is a spontaneous change of the reference voltage based on: a result of the comparison between the voltage of the at least one cell detected by the voltage detecting means and the reference voltage; and a result of the comparison by the voltage comparing means while the reference voltage is relatively changed stepwisely by the plurality of voltage switching circuits, wherein a range of relative change in the reference voltage by the plurality of switching circuits is set to a usage voltage range to be used by the at least one cell within a total voltage range of the at least one cell, the total voltage range being defined from a minimum voltage to a maximum voltage of the at least one cell, and the determining means detects the spontaneous change of the reference voltage based on respective results of comparisons between plural levels of the reference voltage stepwisely switched by the plurality of voltage switching circuits and the voltage of the at least one cell.