BATTERY END COVER ASSEMBLY, BATTERY CELL, BATTERY, AND ELECTRICAL DEVICE
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.
1 . A battery end cover assembly, comprising:
an end cover having a liquid injection hole penetrating along a first direction;
wherein:
the liquid injection hole comprises 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 comprises a first inclined surface inclined toward the second hole segment along the first direction.
2 . The battery end cover assembly according to claim 1 , wherein the first inclined surface is a truncated conical surface.
3 . The battery end cover assembly according to claim 2 , wherein:
the projection of the first inclined surface on a plane perpendicular to the first direction is a circular ring; and
the height L of the first inclined surface in the first direction and the radial width D of the circular ring satisfy: 0.2≤D/L≤35.
4 . The battery end cover assembly according to claim 3 , wherein the height L and the radial width D satisfy: 0.5≤D/L≤3.5.
5 . The battery end cover assembly according to claim 3 , wherein the stepped surface further comprises a planar segment perpendicular to the first direction, and the planar segment is on the outer side of the first inclined surface far from the second hole segment.
6 . The battery end cover assembly according to claim 5 , wherein the area defined by the inner edge of the planar segment is configured to be larger than the area of a liquid outlet of a liquid injection nozzle, and the liquid injection nozzle is the liquid injection nozzle of a liquid injection device for injecting liquid into the liquid injection hole.
7 . The battery end cover assembly according to claim 1 , further comprising:
a first seal nail that is at least partly located in the second hole segment, and fits with the second hole segment in a sealed manner.
8 . The battery end cover assembly according to claim 7 , wherein:
the first seal nail comprises a first segment and a second segment divided along the first direction;
the second segment fits with the second hole segment in a sealed manner;
the maximum cross-sectional area of the first segment is larger than the cross-sectional area of the second hole segment; and
the first segment has a second inclined surface which is capable of closely fitting with the first inclined surface.
9 . The battery end cover assembly according to claim 8 , wherein the first seal nail further comprises a third segment that is connected along the first direction to a side of the second segment far from the first segment, and the maximum cross-sectional area of the third segment is larger than the cross-sectional area of the second hole segment.
10 . The battery end cover assembly according to claim 9 , wherein the third segment has a drum-shaped part adjacent to the second segment, and the maximum cross-sectional area of the third segment is the maximum cross-sectional area of the drum-shaped part.
11 . The battery end cover assembly according to claim 10 , wherein the third segment further comprises a conical or truncated conical part on the drum-shaped part far from the second segment, and the cross-sectional area of the conical or truncated conical part gradually decreases along the first direction.
12 . The battery end cover assembly according to claim 9 , wherein the cross-sectional area of the second hole segment is larger than the cross-sectional area of an end surface on a side of the third segment far from the second segment.
13 . The battery end cover assembly according to claim 12 , wherein the cross-sectional area of the second hole segment is 1.05-1.5 times the cross-sectional area of the end surface on the side of the third segment far from the second segment.
14 . The battery end cover assembly according to claim 11 , wherein the angle β between the generatrix of the conical or truncated conical part and a plane perpendicular to the first direction satisfies: 30°≤β≤50°.
15 . The battery end cover assembly according to claim 7 , further comprising:
a second seal nail that is at least partly located in the first hole segment, and fits with the first hole segment in a sealed manner.
16 . The battery end cover assembly according to claim 15 , wherein a first gap is formed between an end surface on a side of the first seal nail adjacent to the second seal nail and the second seal nail.
17 . The battery end cover assembly according to claim 16 , wherein the value of the first gap is 0.3-0.6 mm.
18 . The battery end cover assembly according to claim 16 , wherein a second gap is formed between the stepped surface and the second seal nail.
19 . The battery end cover assembly according to claim 18 , wherein the value of the second gap is 0.1˜0.4 mm.
20 . The battery end cover assembly according to claim 7 , wherein the material of the first seal nail comprises rubber.