Secondary battery module and method for manufacturing the same

A secondary battery module, comprising:

• a plurality of secondary batteries, each secondary battery having two side surfaces that are flat and parallel to each other;
• and
• a housing comprising a bottom part extending in a horizontal direction, two vertical sidewalls extending parallel to each other in a longitudinal direction at opposite ends of the bottom part, and a ceiling part extending from an upper end of each of the sidewalls and disposed parallel to the bottom part,
• wherein the plurality of secondary batteries are mounted to be stacked in a thickness direction thereof so that side surfaces of outermost secondary batteries of the plurality of secondary batteries face respective sidewalls,
• wherein a rib is located inside each of edges connecting the bottom part and the sidewalls of the housing to each other to have a thickness thicker than other portions of the sidewalls, and
• wherein each side surface of each secondary battery has a length and a width that are greater than a thickness of the secondary battery.