Patent ID: 8552729

Claim:
A state monitoring unit for monitoring a state of an assembled battery that outputs a desired voltage, in which a plurality of unit cells are connected in series, the state monitoring unit comprising: a high voltage side including a plurality of voltage monitoring devices, each device corresponding to respective unit cells among the plurality of unit cells; and a low voltage side electrically isolated with the high voltage side, and including a controller which controls the respective voltage monitoring devices, wherein a common voltage measurement command for instructing a voltage measurement of the unit cells is transmitted from the controller to the respective voltage monitoring devices connected via a communication channel in a daisy-chain scheme, each of the voltage monitoring devices includes: a first transmission unit that transmits, via the communication channel, the common voltage measurement command received from the controller or from one adjacent voltage monitoring device at a leading end side of the communication channel to one adjacent voltage monitoring device at a termination side of the communication channel; a measuring unit that measures the voltage of the corresponding unit cells in response to the received common voltage measurement command; and a second transmission unit that transmits, via the communication channel, the voltage measured by the associated measuring unit and a measured voltage received from and corresponding to one adjacent voltage monitoring device at the termination side of the communication channel to the controller or to the adjacent voltage monitoring device at the leading end side of the communication channel, and the controller checks the number of measured voltages of the unit cells received via the communication channel against the number of voltage monitoring devices to determine whether an abnormality occurs in a reception state of the measured voltages of the unit cells.