Secondary battery

Patent metadata

Field	Value
Publication number	US-12476312-B2
Application number	US-202217719876-A
Country	US
Kind code	B2
Filing date	Apr 13, 2022
Priority date	Apr 15, 2021
Publication date	Nov 18, 2025
Grant date	Nov 18, 2025

Abstract

Disclosed herein is a secondary battery having a vent member. The secondary battery may include an electrode assembly, a case including an accommodation portion to receive the electrode assembly, an electrode lead attached to the electrode assembly and a vent member. The case may include a sealing portion to seal the electrode assembly therein. The sealing portion may include a sealant resin to form a seal around the electrode assembly. The electrode lead may extend away from the case along a first direction. The sealing portion may include an inclined sealing portion adjacent the electrode lead. The inclined sealing portion may extend along a second direction. The second direction may be non-orthogonal to the first direction. The vent member may be disposed in the inclined sealing portion. The vent member may include a vent resin having a lower melting point than the sealant resin.

First claim

The invention claimed is:

1 . A secondary battery, comprising:
an electrode assembly; a case including an accommodation portion to receive the electrode assembly and a sealing portion to seal the electrode assembly therein, the sealing portion including a sealant resin to form a seal around the electrode assembly; an electrode lead attached to the electrode assembly, the electrode lead extending away from the case along a first direction, wherein the sealing portion includes an inclined sealing portion adjacent the electrode lead, the inclined sealing portion extending along a second direction, the second direction being non-orthogonal to the first direction, a vent member disposed in the inclined sealing portion, the vent member including a vent resin having a lower melting point than the sealant resin, and a lead film surrounding an outer surface of the electrode lead, the lead film being interposed between the electrode lead and the sealing portion, the vent member extending through the accommodation portion such that the vent member at least partially overlaps or contacts the lead film in the accommodation portion.

2 . The secondary battery according to claim 1 , wherein the inclined sealing portion has an inclination angle of 10° to 80°, the inclination angle being defined as an angle between the first direction and the second direction.

3 . The secondary battery according to claim 1 , wherein the vent member includes a first side extending parallel to the second direction.

4 . The secondary battery according to claim 3 , wherein a vent forms along a direction perpendicular to the first side of the vent member.

5 . The secondary battery according to claim 1 , wherein the vent member includes a first portion and a second portion,
the first portion extending along the second direction such that the first portion may at least partially overlap or contact the lead film in the accommodation portion, the second portion extending along a third direction orthogonal to the second direction.

6 . The secondary battery according to claim 5 , wherein the vent member defines an L shape.

7 . The secondary battery according to claim 5 , wherein the second portion includes a tapered edge that extends into the accommodation portion along the electrode assembly.

8 . The secondary battery according to claim 5 , wherein an outer end of the first portion is spaced apart from a inner end of the sealing portion adjacent the lead film, the outer end of the first portion being located in the accommodation portion.

9 . The secondary battery according to claim 5 , wherein the second portion does not overlap or contact the lead film.

10 . The secondary battery according to claim 1 , wherein a width of the vent member varies in a direction perpendicular to the second direction.

11 . The secondary battery according to claim 1 , wherein the vent member defines any of a circular, oval, stepped, triangular and quadrilateral shape.

12 . The secondary battery according to claim 1 , wherein a thickness of the vent member varies in a direction perpendicular to the second direction.

13 . The secondary battery according to claim 1 , wherein an area of a region of the vent member overlapping or contacting the lead film is 1% to 30% of an area of a region of the lead film not contacting or overlapping the electrode lead.

14 . The secondary battery according to claim 1 , wherein the vent resin includes a linear low-density polyethylene having a comonomer with a carbon number of 6 or more.

15 . The secondary battery according to claim 1 , wherein the vent member melts at 100° C. to 120° C. to vent gases from the accommodation portion to an exterior of the secondary battery.

16 . The secondary battery according to claim 15 , wherein the vent member vents gases from the accommodation portion when the accommodation portion is at a pressure of 0.7 atm or above.

17 . The secondary battery according to claim 1 , wherein the vent member has a maximum sealing strength of less than 6 kgf/15 mm at 100° C. or above.

18 . The secondary battery according to claim 1 , wherein the vent member has an average sealing strength of less than 4.5 kgf/15 mm at 100° C. or above.

19 . The secondary battery according to claim 1 , wherein the vent member has a maximum sealing strength of 6 kgf/15 mm or more at room temperature to 60° C.

20 . The secondary battery according to claim 1 , wherein the vent member has an average sealing strength of 4.5 kgf/15 mm or more at room temperature to 60° C.

21 . The secondary battery according to claim 14 , wherein the linear low-density polyethylene is polymerized in the presence of a metallocene catalyst.

22 . The secondary battery according to claim 14 , wherein a content of the comonomer with a carbon number of 6 or more is 15 weight % or less based on 100 weight % of the linear low-density polyethylene.

23 . The secondary battery according to claim 1 , wherein the vent resin has a poly dispersity index (PDI) of 4 or less.

24 . The secondary battery according to claim 1 , wherein a difference between a crystallization temperature of the sealant resin and a crystallization temperature of the vent resin is 10° C. or less.

25 . The secondary battery according to claim 1 , wherein the vent resin has a melting point of 100° C. to 130° C.

26 . The secondary battery according to claim 1 , wherein the vent resin has a weight-average molecular weight of 100,000 g/mol to 400,000 g/mol.

27 . The secondary battery according to claim 1 , wherein the secondary battery is a pouch-type secondary battery.

28 . The secondary battery according to claim 1 , wherein the vent member has a maximum sealing strength of less than 6 kgf/15 mm at 100° C. to 120° C.

29 . The secondary battery according to claim 1 , wherein the vent member has an average sealing strength of less than 4.5 kgf/15 mm at 100° C. to 120° C.

30 . The secondary battery according to claim 14 , wherein a content of the comonomer with the carbon number of 6 or more is from 5 weight % to 15 weight % based on 100 weight % of the linear low-density polyethylene.

31 . The secondary battery according to claim 1 , wherein the vent member has a maximum sealing strength of less than 3 kgf/15 mm at 120° C. or more.

32 . The secondary battery according to claim 1 , wherein the vent member has an average sealing strength of less than 2 kgf/15 mm at 120° C. or more.

33 . A secondary battery, comprising:
an electrode assembly; a case including an accommodation portion to receive the electrode assembly and a sealing portion to seal the electrode assembly therein, the sealing portion including a sealant resin to form a seal around the electrode assembly; an electrode lead attached to the electrode assembly, the electrode lead extending away from the case along a first direction, wherein the sealing portion includes a convex sealing portion adjacent the electrode lead, the convex sealing portion extending along a convex curve from the first direction to a second direction, the second direction being orthogonal to the first direction, a vent member disposed in the convex sealing portion, the vent member including a vent resin having a lower melting point than the sealant resin, an

Assignees

• Lg Energy Solution Ltd

Inventors

• Kim Sang-Hun
• Song Dae-Woong
• Kang Min-Hyeong
• Yu Hyung-Kyun
• Lim Hun-Hee
• Hwang Soo-Ji

Classifications

• H01M50/342

  Non-re-sealable arrangements · CPC title

• H01M50/193

  Organic material · CPC title

• H01M50/129

  with two or more layers of only organic material · CPC title

• H01M50/178

  for pouch or flexible bag cells · CPC title

• H01M50/3425

  in the form of rupturable membranes or weakened parts, e.g. pierced with the aid of a sharp member · CPC title