Pouch film stack and secondary battery

Patent metadata

Field	Value
Publication number	US-12537246-B2
Application number	US-202218573259-A
Country	US
Kind code	B2
Filing date	Sep 28, 2022
Priority date	Oct 1, 2021
Publication date	Jan 27, 2026
Grant date	Jan 27, 2026

Abstract

A pouch film stack according to the present invention includes a base layer, a gas barrier layer, and a sealant layer stacked in that order. The sealant layer includes a first sealant layer located adjacent to the gas barrier layer and a second sealant layer stacked on the first sealant layer. A percentage difference in yield strength between the first and second sealant layers (ΔY) is 66% to 120%, where ΔY is defined as: {(Yield strength of second sealant layer−Yield strength of first sealant layer)/Yield strength of first sealant layer}×100.

First claim

The invention claimed is:

1 . A pouch film stack, comprising:
a base layer, a gas barrier layer, and a sealant layer, wherein the gas barrier layer is stacked on the base layer, and the sealant layer is stacked on the gas barrier layer; wherein the sealant layer includes: a first sealant layer including acid modified polypropylene (PPa) located adjacent to the gas barrier layer; and a second sealant layer including cast polypropylene (CPP) stacked on the first sealant layer, wherein the yield strength of the first sealant layer is less than the yield strength of the second sealant layer, and wherein a percentage difference in yield strength between the first and second sealant layers (ΔY) is 66% to 120%, according to the following equation:

Δ
⁢
Y

=

{

(

Yield
⁢

strength
⁢

of
⁢

second
⁢

sealant
⁢

layer

-

Yield
⁢

strength
⁢

of
⁢

first
⁢

sealant
⁢

layer

)

/

Yield
⁢

strength
⁢

of
⁢

first
⁢

sealant
⁢

layer

}

×
100.

2 . The pouch film stack of claim 1 , wherein a difference between the yield strength of the first sealant layer and the yield strength of the second sealant layer is less than or equal to 8 N/15 mm.

3 . The pouch film stack of claim 1 , wherein the yield strength of the first sealant layer is in a range from 7 N/15 mm to 15 N/15 mm.

4 . The pouch film stack of claim 1 , wherein the yield strength of the second sealant layer is in a range from 10 N/15 mm to 30 N/15 mm.

5 . The pouch film stack of claim 1 , wherein a thickness ratio between the first sealant layer and the second sealant layer is in a range from 1:0.3 to 1:3.

6 . The pouch film stack of claim 1 , wherein a thickness of the first sealant layer is in a range from 10 μm to 60 μm.

7 . The pouch film stack of claim 1 , wherein a thickness of the second sealant layer is in a range from 20 μm to 70 μm.

8 . The pouch film stack of claim 1 , wherein the first sealant layer and the second sealant layer comprise polypropylene.

9 . The pouch film stack of claim 1 , wherein the gas barrier layer comprises aluminum.

10 . The pouch film stack of claim 1 , wherein peel strength between the gas barrier layer and the first sealant layer is greater than 23 N/15 mm.

11 . The pouch film stack of claim 1 , wherein an additive is added to at least one of the first sealant layer and the second sealant layer.

12 . The pouch film stack of claim 11 , wherein the additive comprises at least one of carbon fiber, glass fiber and aramid fiber.

13 . A pouch-type battery case comprising two of the pouch film stacks of claim 1 stacked such that a sealing portion is defined by the second sealant layers of each of the pouch film stacks sealed together,
wherein a breaking strength of the sealing portion measured at 25° C. is greater than or equal to 100 N/15 mm.

14 . The pouch-type battery case of claim 13 , wherein the sealing portion is formed by sealing the second sealant layers of each of the pouch film stacks together for 2 seconds under a condition of 180° C. and 0.4 Mpa.

15 . A pouch-type battery case comprising two of the pouch film stacks of claim 1 stacked such that a sealing portion is defined by the second sealant layers of each of the pouch film stacks sealed together,
wherein a breaking strength of the sealing portion measured at 60° C. is greater than or equal to 80 N/15 mm.

16 . The pouch-type battery case of claim 15 , wherein the sealing portion is formed by sealing the second sealant layers of each of the pouch film stacks together for 2 seconds under a condition of 180° C. and 0.4 Mpa.

17 . A secondary battery comprising:
a pouch-type battery case including at least one of the pouch film stack of claim 1 ; and an electrode assembly accommodated inside the pouch-type battery case.

Assignees

• Lg Energy Solution Ltd

Inventors

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

Classifications

• H01M50/133

  Thickness · CPC title

• H01M50/131

  characterised by physical properties, e.g. gas permeability, size or heat resistance · CPC title

• H01M50/121

  Organic material · CPC title

• H01M50/119

  Metals · CPC title

• H01M50/105 Primary

  Pouches or flexible bags · CPC title