Rechargeable battery pack

A rechargeable battery pack, comprising:

• at least one cell stack comprising a plurality of battery cells stacked in a first direction;
• a center frame comprising a first bottom and a first side wall supporting the at least one cell stack;
• a first side frame and a second side frame each comprising a second bottom and a second side wall, the first side frame and the second side frame being coupled to the center frame in a second direction crossing the first direction and supporting a cell narrow side of the at least one cell stack;
• and
• a first end frame and a second end frame coupled to both ends of the center frame, the first side frame, and the second side frame in the first direction to support a cell wide side of the at least one cell stack.