Patent ID: 8723527

Claim:
A battery monitoring system, comprising: an integrated circuit including a voltage measurement unit measuring a cell voltage value of each of a plurality of battery cells that are connected in series; and a control circuit that monitors a state of each of the plurality of battery cells, based on the cell voltage value measured by the voltage measurement unit; and wherein the integrated circuit comprises: a first storage circuit that stores the cell voltage value measured by the voltage measurement unit and a pseudo voltage value representing a voltage corresponding to excessive charge; a second storage circuit that stores an excessive charge threshold value; a first selection unit that selects any voltage value of the cell voltage value and the pseudo voltage value stored in the first storage circuit, upon command from the control circuit; a decision unit to which the any voltage value selected by the first selection unit is input, deciding whether or not the any voltage value is larger than the excessive charge threshold value; and an excessive charge detection information outputting unit that outputs excessive charge detection information if the decision unit decides the any voltage value selected by the first selection unit is greater than the excessive charge threshold value; and the control circuit inputs pseudo voltage information to the battery state detection circuit, controls the first selection unit to select the pseudo voltage value, and thereby diagnoses whether or not an excessive charge detection circuit including the decision unit, the second storage circuit, and the excessive charge detection information outputting unit are operating normally, based on the excessive charge detection information output by the excessive charge detection information outputting unit.