Battery monitoring system and battery monitoring device

A battery monitoring device that is included in a battery monitoring system, the battery monitoring system including:

• a plurality of battery monitoring devices that are serially connected to each other, that are each provided for one of a plurality of serially connected battery cell groups, and that monitor a voltage of a plurality of battery cells included in each of the plurality of battery cell groups;
• and a control circuit that is connected to one battery monitoring device of the plurality of battery monitoring devices and that transmits a first activation signal to the one battery monitoring device, each particular one of the battery monitoring devices included in the battery monitoring system comprising:
• a constant voltage generation circuit that generates and outputs a constant voltage;
• a first activation circuit that outputs a second activation signal if the first activation circuit receives the first activation signal from the control circuit;
• and
• a second activation circuit that outputs a third activation signal in response to recognizing the constant voltage generated by the constant voltage generation of another of the battery monitoring devices that is connected to the particular battery monitoring device, and
• wherein the constant voltage generation circuit generates the constant voltage if the constant voltage generation circuit receives the second activation signal or the third activation signal.