Secondary Battery

Patent metadata

Field	Value
Publication number	US-2023369710-A1
Application number	US-202218029850-A
Country	US
Kind code	A1
Filing date	Apr 15, 2022
Priority date	Apr 15, 2021
Publication date	Nov 16, 2023
Grant date	—

Abstract

Disclosed herein is a secondary battery, which includes an electrode assembly; an electrode lead attached to the electrode assembly; a case configured to accommodate the electrode assembly therein; a lead film formed to surround a part of an outer surface of the electrode lead and interposed between the electrode lead and the case; a vent region formed in at least a part of the case; and a vent member inserted into the vent region and having a structure of three or more layers, wherein the vent member contains a linear low-density polyethylene having a comonomer with a carbon number of 6 or more in outermost layers and contains a resin having a higher melting point than the linear low-density polyethylene having a comonomer with a carbon number of 6 or more in a middle layer.

First claim

What is claimed is:

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 formed to surround a part of an outer surface of the electrode lead and interposed between the electrode lead and the case; a vent region formed in at least a part of the case; and a vent member inserted into the vent region and having a structure of three or more layers, wherein the vent member contains a linear low-density polyethylene having a comonomer with a carbon number of 6 or more in outermost layers and contains a resin having a higher melting point than the linear low-density polyethylene having a comonomer with a carbon number of 6 or more in between the outermost layers.

2 . The secondary battery according to claim 1 ,
wherein a vent occurs between the case and the outermost layer.

3 . The secondary battery according to claim 1 ,
wherein the resin having a higher melting point than the linear low-density polyethylene having a comonomer with a carbon number of 6 or more has a melting point between 120° C. and 140° C.

4 . The secondary battery according to claim 1 ,
wherein the linear low-density polyethylene having a comonomer with a carbon number of 6 or more has a melting point of between 100° C. and 120° C.

5 . The secondary battery according to claim 1 ,
wherein the resin having a higher melting point than the linear low-density polyethylene having a comonomer with a carbon number of 6 or more includes a high-density polyethylene, random polypropylene, or a mixture thereof.

6 . The secondary battery according to claim 1 ,
wherein the case includes a sealing portion formed to seal the electrode assembly, the sealing portion contains a sealant resin, and the linear low-density polyethylene of the vent member having a comonomer with a carbon number of 6 or more has a lower melting point than the sealant resin.

7 . The secondary battery according to claim 1 ,
wherein the outermost layers contain a linear low-density polyethylene having a comonomer with a carbon number of 6 to 8.

8 . The secondary battery according to claim 1 ,
wherein the vent member melts at 100° C. to 120° C. to vent a gas, or wherein the vent member is vented at a pressure of about 1.5 atm or above.

9 . (canceled)

10 . 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.

11 . 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.

12 . 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.

13 . 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.

14 . The secondary battery according to claim 1 ,
wherein the linear low-density polyethylene having a comonomer with a carbon number of 6 or more is polymerized in the presence of a metallocene catalyst.

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

16 . The secondary battery according to claim 1 ,
wherein the linear low-density polyethylene having a comonomer with a carbon number of 6 or more has a poly dispersity index (PDI) of 4 or less.

17 . The secondary battery according to claim 6 ,
wherein a difference between a crystallization temperature of the sealant resin and a crystallization temperature of the linear low-density polyethylene having a comonomer with a carbon number of 6 or more is 10° C. or less.

18 . The secondary battery according to claim 17 ,
wherein the linear low-density polyethylene having a comonomer with a carbon number of 6 or more has a crystallization temperature of 90° C. to 115° C.

19 . The secondary battery according to claim 1 ,
wherein the linear low-density polyethylene having a comonomer with a carbon number of 6 or more has a weight-average molecular weight of 100,000 g/mol to 400,000 g/mol.

20 . The secondary battery according to claim 6 , wherein the vent region is located in the sealing portion at a corner of the case.

21 . (canceled)

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

Assignees

• Lg Energy Solution Ltd

Inventors

• Hwang Soo-Ji
• Kim Sang-Hun
• 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

• H01M50/105

  Pouches or flexible bags · CPC title

• H01M50/193

  Organic material · CPC title

• H01M50/197 Primary

  having a layered structure · CPC title

• H01M50/375 Primary

  Vent means sensitive to or responsive to temperature · CPC title