Battery module including foldable side plate and method for manufacturing same

A battery module, comprising:

• a first module and a second module, each including a cell stack having a plurality of battery cells stacked vertically and a bus bar frame assembly configured to cover a front surface and a rear surface of the cell stack;
• a pair of foldable side plates including a first side plate configured to cover and pressurize one side surface and another side surface of the first module and a second side plate configured to cover and pressurize one side surface and another side surface of the second module and coupled to the first side plate by a hinge to rotate between a folded condition and a unfolded condition, the first module and the second module being arranged side by side in a width direction in the folded condition, the first module and the second module being arranged side by side in a longitudinal direction in the unfolded condition;
• and
• an upper housing coupled to each of the pair of foldable side plates to cover upper surfaces of the first module and the second module, wherein the foldable side plates are configured to form an external enclosure around the cell stacks and maintain a continuous pressurization force across the cell stacks during a transition from the folded condition to the unfolded condition, the pressurization force acting along a direction parallel to the upper housing.