Secondary Battery

Patent metadata

Field	Value
Publication number	US-2023378593-A1
Application number	US-202218029249-A
Country	US
Kind code	A1
Filing date	Apr 14, 2022
Priority date	Apr 14, 2021
Publication date	Nov 23, 2023
Grant date	—

Abstract

Disclosed herein is a secondary battery. The second battery can includes an electrode assembly, an electrode lead attached to the electrode assembly, and case configured to accommodate the electrode assembly therein. A lead film can be disposed around a part of an outer surface of the electrode lead and interposed between the electrode lead and the case. A vent region can be formed in at least a part of the case. A vent member can be disposed in the vent region. The vent member can have a structure defining a thickness and contain a linear low-density polyethylene having a comonomer with a carbon number of 6 or more. The thickness can be more than 50 μm and less than 200 μm.

First claim

1 . A secondary battery, comprising:
an electrode assembly; an electrode lead attached to the electrode assembly; a case configured to accommodate the electrode assembly therein; a lead film surrounding a part of an outer surface of the electrode lead and interposed between the electrode lead and the case; a vent region, the vent region being defined by at least a part of the case; and a vent member being disposed in the vent region, the vent member defined by a structure having a thickness, the vent member containing a linear low-density polyethylene having a comonomer with a carbon number of 6 or more, wherein the thickness is greater than 50 μm or more and less than 200 μm.

2 . The secondary battery according to claim 1 ,
wherein the thickness is 50 μm to 100 μm.

3 . The secondary battery according to claim 1 , wherein the vent member contains a linear low-density polyethylene having a comonomer with a carbon number of 6 to 8.

4 . The secondary battery according to claim 1 ,
wherein the case includes a sealing portion to seal the electrode assembly, the sealing portion containing a sealant resin, the linear low-density polyethylene of the vent member having a lower melting point than the sealant resin.

5 . The secondary battery according to claim 1 , wherein the vent member melts at 100° C. to 120° C. to vent a gas.

6 . The secondary battery according to claim 5 , wherein the vent member is vented at a pressure of 1.5 atm or above.

7 . 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.

8 . 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.

9 . 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.

10 . 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.

11 . The secondary battery according to claim 1 ,
wherein the linear low-density polyethylene is polymerized in the presence of a metallocene catalyst.

12 . The secondary battery according to claim 1 , 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.

13 . The secondary battery according to claim 1 , wherein the linear low-density polyethylene has a poly dispersity index (PDI) of 4 or less.

14 . The secondary battery according to claim 4 , wherein a difference between a crystallization temperature of the sealant resin and a crystallization temperature of the linear low-density polyethylene is 10° C. or less.

15 . The secondary battery according to claim 14 , wherein the linear low-density polyethylene has a crystallization temperature of 90° C. to 115° C.

16 . The secondary battery according to claim 1 , wherein the linear low-density polyethylene has a melting point of 100° C. to 130° C.

17 . The secondary battery according to claim 1 , wherein the linear low-density polyethylene has a weight-average molecular weight of 100,000 g/mol to 400,000 g/mol.

18 . The secondary battery according to claim 1 ,
wherein the structure of the vent member has a width narrowing along a protruding direction of the electrode lead.

19 . The secondary battery according to claim 1 ,
wherein the structure of the vent member has any one of circular, oval, stepped, triangular and trapezoidal shapes.

20 . The secondary battery according to claim 4 , wherein the vent region is located in the sealing portion.

21 . The secondary battery according to claim 20 , wherein the vent region is located in the sealing portion at a corner of the case.

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

Assignees

• Lg Energy Solution Ltd

Inventors

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

Classifications

• H01M50/3425 Primary

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

• H01M50/178

  for pouch or flexible bag cells · CPC title

• H01M50/105

  Pouches or flexible bags · CPC title

• H01M50/129 Primary

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

• H01M50/375 Primary

  Vent means sensitive to or responsive to temperature · CPC title