Patent ID: 8649935

Claim:
A battery system, comprising: a battery unit that is constituted with a plurality of cell groups, which are electrically connected in series, each include a plurality of battery cells, which are electrically connected in series; integrated circuits that are each provided in correspondence to one of the cell groups of the battery unit and each input terminal voltages at the battery cells in a corresponding cell group to measure each of the terminal voltages at the battery cells, wherein the integrated circuits each comprise: a selection circuit that selects a terminal voltage of a battery cell that is a measurement target from among the terminal voltages at the battery cells in the corresponding cell group; an AD converter that converts the terminal voltage, which is outputted from the selection circuit, from an analog value to a digital value; a power source circuit that generates a power source voltage supplied to circuits in an integrated circuit; and a voltage generation circuit that generates a known value voltage, wherein in case that a voltage is measured for diagnosing the voltage generation circuit, the selection circuit selects the known value voltage and the AD converter converts the known value voltage, which is outputted from the selection circuit, from an analog value to a digital value.