Battery module, and battery pack and energy storage system including the same

A battery module, comprising:

• a plurality of battery cells, each battery cell having a top surface, a bottom surface opposite the top surface, a first end surface and a second end surface opposite the first end surface, the plurality of battery cells stacked in a first direction;
• a module case configured to accommodate the plurality of battery cells;
• and
• at least one forming portion, the at least one forming portion comprising:
• a first forming groove extending in a second direction and having a first end and a second end spaced from each other in the second direction, the first forming groove engaged with the top surface of a corresponding battery cell of the plurality of battery cells;
• and
• a second forming groove formed at each of the first end and the second end of the first forming groove, the second grooves respectively contacting the first end surface and the second end surface of a corresponding battery cell,
• wherein the module case includes first and second cases coupled to each other by hooking and having shapes corresponding to each other.