Battery pack

A battery pack, comprising:

• a plurality of stacks, each of the plurality of stacks including
• a plurality of battery cells arranged side by side in a first direction, each of the plurality of battery cells including a plurality of electrode terminals disposed side by side in a second direction orthogonal to the first direction, and
• separators;
• and
• a case member including
• a sealed inner space that accommodates the plurality of stacks,
• a side surface portion extending in a direction orthogonal to the first direction or in a direction orthogonal to the second direction, and
• a reinforcing rib provided on the side surface portion, wherein
• the reinforcing rib extends in a third direction orthogonal to the first direction and the second direction or in a direction obliquely intersecting the third direction,
• the plurality of stacks is arranged in the second direction and in direct abutment with the side surface portion,
• the side surface portion includes a pair of side surfaces located on both sides of the plurality of stacks in the first direction, respectively,
• the reinforcing rib is provided on an outer side of each of the pair of side surfaces, the outer side facing away from the sealed inner space,
• the pair of side surfaces defines the sealed inner space and directly supports the plurality of stacks in the first direction,
• the case member includes a first flange and a second flange, each of the first flange and the second flange protruding with respect to the side surface portion in the first direction and extending in the second direction,
• the first flange and the second flange are separated from each other along the third direction, and
• the reinforcing rib extends from the first flange to reach the second flange.