Battery pack and manufacturing method thereof

A battery pack comprising:

• a battery case in a substantially box shape extending in a first direction and a second direction that are orthogonal to each other and form a horizontal plane;
• a plurality of battery cells arranged in the battery case;
• and
• a plurality of coolant jackets comprising coolant passages therein and cooling the plurality of battery cells, wherein
• the plurality of battery cells constitute cell joined bodies each with multiple battery cells arranged and joined in a row in the second direction,
• the cell joined body and the coolant jacket are alternately arranged in surface contact with each other in the first direction, and
• each of the coolant jackets is connected to coolant circulation pipes provided on both sides in the second direction, and at least a part of the coolant jackets is a reinforcing plate-type coolant jacket configured such that upper parts of both end parts in the second direction of the reinforcing plate-type coolant jacket are extended in the second direction and are joined to upper parts of end plates constituting both end parts of the battery case in the second direction while avoiding the coolant circulation pipes to enhance a rigidity of the battery case.