Lithium battery

A lithium battery comprising:

• a battery module having battery cells electrically connected to each other;
• an upper plate member forming an upper surface of the lithium battery, the upper plate member covering an upper end of the battery module contained in the lithium battery;
• a lower plate member forming a bottom space that contains the battery module therein;
• side plate members comprising a pair of side plate bodies provided at positions spaced apart from each other to form opposite side surfaces of the lithium battery, the side plate bodies being coupled at upper and lower ends thereof to the lower plate member and the upper plate member, wherein one of the pair of side plate bodies of the side plate members comprises a connection plate extending therefrom in one direction, with a connection protrusion protruding downwards from a lower surface of the connection plate, and the other of the pair of side plate bodies has a connection depression into which a connection plate of another lithium battery is able to be seated;
• and
• end plate members coupled to front and rear ends of the side plate members to form front and rear surfaces of the lithium battery,
• wherein each of the side plate members comprises:
• a first insert plate provided and stepped on the upper end of each of the pair of the side plate bodies, the first insert plate being inserted into the upper plate member and seated onto an inner surface of the upper plate member;
• a second insert plate protruding downwards from the lower end of each of the pair of the side plate bodies such that a stepped portion is formed therebewteen, the second insert plate being inserted into the lower plate member and seated onto the stepped portion formed on each of a pair of bottom side panels of the lower plate member;
• and
• front and rear end parts bent from the front and rear ends of each of the side plate members towards the opposing other side plate body, the front and rear end parts extending in a vertical direction,
• wherein each of the first insert plate and the second insert plate comprises guides extending towards the front and rear end parts, and bent towards the opposing other side plate body, and protruding from the front and rear end parts.