Abstract: According to one embodiment, a battery module includes first to fourth batteries and a case in which these batteries are housed. In the case, a first partition wall partitions the first and the second batteries and partitions the third and fourth batteries in a first direction, and a second partition wall partitions the first and third batteries and partitions the second and fourth batteries in a second direction intersecting the first direction. A fastening member fastens case members to each other at an intersection of the above two partition walls. The case includes a rib protruding on a surface of at least one of the first and second partition walls.

Abstract: A battery pack includes a lower case having a rectangular box shape with a top opened, and including a bottom part, a plurality of first walls, and second walls; an upper case having a rectangular box shape with a bottom opened, and including a top part opposing the lower case; and a plurality of secondary batteries each including a top face provided with a positive-electrode terminal and a negative-electrode terminal, principal faces, a pair of lateral faces extending between the principal faces, and a bottom face, and deformable ribs.