Patent ID: 7521896

Claim:
An abnormal voltage detector apparatus for use in an assembled battery comprising a plurality of battery blocks connected in series to each other, said abnormal voltage detector apparatus detecting voltage abnormality in said assembled battery, each battery block comprising at least one secondary battery, said abnormal voltage detector apparatus comprising: a detecting part: for detecting whether or not each of said battery blocks is in a voltage abnormality state by comparing one of a voltage of said each battery block and each battery measuring voltage with a predetermined reference-voltage, wherein each battery measuring voltage is lowered from a voltage of each associated battery block, for generating abnormality detecting signals for each battery block, each abnormality detecting signal containing information about a detected result, for calculating a time ratio of a time interval, for which said assembled battery is in a voltage abnormality state, to a predetermined time interval, based on the abnormality detecting signals, and for detecting a voltage abnormality of said assembled battery based on the calculated time ratio.