Battery module, battery, energy storage apparatus, and electric apparatus

A battery module, comprising:

• a battery cell group, comprising multiple battery cells stacked in a first direction;
• and
• end plates, wherein the end plate is located at an end of the battery cell group in the first direction;
• wherein
• the multiple battery cells comprise at least one first battery cell, and the first battery cell comprises:
• a housing, wherein the housing has an opening in a second direction, the housing has first walls in the first direction, the first wall comprises a first body portion and a first thickened portion arranged in the second direction, the first body portion is farther from the opening than the first thickened portion, and thickness of the first thickened portion is larger than thickness of the first body portion, the first direction and the second direction being perpendicular to each other;
• and
• an end cover, wherein the end cover is connected to the housing to close the opening;
• wherein in a direction from the first body portion towards the first thickened portion, at least a part of the first thickened portion exceeds the end plate.