Abstract: A battery end cover assembly includes an end cover having a liquid injection hole penetrating along a first direction. The liquid injection hole includes a first hole segment and a second hole segment divided along the first direction; the cross-sectional area of the first hole segment is larger than the cross-sectional area of the second hole segment; a stepped surface is formed between the first hole segment and the second hole segment; and the stepped surface includes a first inclined surface inclined toward the second hole segment along the first direction.

Abstract: A battery cell includes an electrode assembly including a body and a tab, and a connecting part including a terminal connecting portion and a tab connecting portion. The terminal connecting portion is configured to connect an electrode terminal, the tab connecting portion is configured to connect the tab, and the tab connecting portion has a surface facing the body. The tab includes a first section connected to the body, a second section fixed on the surface of the tab connecting portion, and a corner section connected between the first section and the second section. The corner section exceeds the surface of the tab connecting portion in a direction from the body toward the connecting part.