Patent ID: 7863781

Claim:
A power unit made from a plurality of series-connected battery modules, comprising: a cover for covering positive and negative terminals of the battery modules; and a first safety switch that opens and closes a connection among the battery modules by insertion and removal of a service plug which regulates removal of the cover by engaging the cover, wherein the power unit further comprises a second safety switch in which a connector that closes the connection among the battery modules in a state of being attached to the cover is projectingly provided on a back of the cover, and the connection among the battery modules is opened and closed by means of insertion and removal of the connector associated with attachment and removal of the cover as well as of insertion and removal of the service plug, and the second safety switch is formed of a switch main body and the connector, and is configured such that a current-carrying circuit among the battery modules is closed by inserting the connector for engagement, and is opened by removing the connector.