Patent ID: 8428896

Claim:
A malfunction detecting apparatus comprising: a plurality of voltage detecting devices for detecting a voltage between both terminals of each unit cell, which is a secondary battery type, included in respective blocks, the voltage detecting device being provided for each block of the respective blocks divided from a battery pack formed with a plurality of unit cells connected in series with each other; and a malfunction detecting device detecting an abnormal condition of the voltage detecting devices based on the voltage between both terminals of each cell, which is detected by each voltage detecting device, wherein the malfunction detecting device controls each voltage detecting device to detect the voltage between both terminals of one unit cell from among the unit cells included in each block, which is provided correspondingly to each of the voltage detecting devices, and detects the abnormal condition of the voltage detecting device when a dispersion of each detected voltage between both terminals is at least a threshold value determined by a detection accuracy of the voltage detecting devices, said malfunction detection apparatus further comprising an equalization device equalizing each voltage between both terminals of the unit cells, based on the voltages between both terminals of the unit cells which are detected by the plurality of voltage detecting devices when a vehicle ignition is switched off, wherein the malfunction detecting device controls each voltage detecting device to detect the voltage between both terminals of one unit cell from among the unit cells included in each block at the same time, which is provided correspondingly to each of the voltage detecting devices when the vehicle ignition is switched on, such that, just after switching the vehicle ignition on, the voltage between both terminals of the unit cells is almost equal, with variations of the voltage between both terminals of the unit cells detected when switching on the vehicle ignition being caused by the abnormal condition of the voltage detecting unit.