A battery pack includes a plurality of battery modules disposed in a front and rear direction. Each of the battery modules includes a plurality of battery cells; a module housing; and a connection plate including a contact portion at an upper or lower portion of the plurality of battery cells and having a plurality of connection terminals in a portion thereof and respectively electrically contacted and connected to the electrode terminals at the plurality of battery cells, and a connection portion bent at least once from one end of the contact portion to extend in at least one direction among an upper direction, a lower direction, a front direction and a rear direction so that the bent and extending region of the connection portion is on a left or right outer wall of the module housing to contact a part of a connection plate of another battery module.