Abstract: A feeder circuit for a main relay to control ON of OFF of an electric supply from a high-voltage battery is constituted at least by a first harness, the main relay, a second harness and switch means which are connected in series from a plus-terminal side of a low-voltage battery to a vehicle-body ground side. The first harness and the second harness are arranged to be adjacent to each other in a specified range having a specified length so that both thereof in the above-described specified range are damaged in a vehicle collision or the like.

Abstract: A feeder circuit for a main relay to control ON of OFF of an electric supply from a high-voltage battery is constituted at least by a first harness, the main relay, a second harness and switch means which are connected in series from a plus-terminal side of a low-voltage battery to a vehicle-body ground side. The first harness and the second harness are arranged to be adjacent to each other in a specified range having a specified length so that both thereof in the above-described specified range are damaged in a vehicle collision or the like.

Abstract: A temperature/voltage detecting unit has a temperature detector and a voltage detector. The temperature detector has a light electric system stabilized power supply for stabilizing a light electric system power supply voltage, a temperature resistance element provided close to a corresponding battery element, for changing its resistance value based on a change in temperature, and a voltage-to-frequency converter operating based on a voltage from the light electric system stabilized power supply, for detecting a terminal voltage of the temperature resistance element to which a constant current flows from the light electric system stabilized power supply, converting this value into frequency information and outputting the frequency information.

Abstract: A hydrogen detector detects a concentration of hydrogen gas in an enclosed space communicating with an accommodation space for accommodating a battery, a hydrogen gas expeller is operative for expelling hydrogen gas from the enclosed space, a controller responds to a concentration of hydrogen gas detected by the detector, as the detected concentration exceeds a lower significant concentration, to provide a control signal for driving the expeller, an alarm system is operative for providing an alarm on an abnormal concentration of hydrogen gas, and another controller responds to the concentration of hydrogen gas detected by the detector, as the detected concentration exceeds a higher significant concentration, to provide a control signal for driving the alarm system.