Pouch, secondary battery including the same, and method for manufacturing the same

Abstract

The present invention relates to a pouch, a secondary battery including the pouch, and a manufacturing method thereof. The manufacturing method for a secondary battery according to the present invention includes a hole forming process for forming ventilation holes in an aluminum sheet, a laminating process for laminating a polymer layer on the aluminum sheet to form a pouch, a housing process for housing an electrode assembly in the pouch, and a sealing process for sealing the outer periphery of the pouch.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0182658, filed on December 23, 2020, and all the contents disclosed in the document of the Korean Patent Application are incorporated herein by reference in their entirety. The present invention relates to a pouch, a secondary battery including the same, and a method for manufacturing the same.

Background Art

[0002] Unlike primary batteries, secondary batteries are rechargeable and have been actively researched and developed in recent years due to the possibility of miniaturization and increased capacity. As the technology development and demand for mobile devices increase, the demand for secondary batteries as an energy source has been rapidly increasing.

[0003] Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries according to the shape of the battery case. In a secondary battery, an electrode assembly mounted inside the battery case is a rechargeable power generation element having a laminated structure of electrodes and a separator.

[0004] The electrode assembly can be generally classified into a jelly-roll type in which a separator is interposed between a sheet-shaped positive electrode and a negative electrode coated with an active material and wound, a stack type in which a plurality of positive electrodes and negative electrodes are sequentially laminated with a separator interposed therebetween, and a stack & folding type in which unit cells of the stack type are wound with a long separation film.

[0005] During the driving process of a secondary battery, due to influences such as changes in temperature and potential, gas is generated due to decomposition of the internal electrolyte. Although it is a small amount under normal driving conditions, considering that the battery guarantee period is more than 10 years, it is at a level that cannot be ignored. Various studies have been conducted to discharge the gas generated inside the cell, and studies have also been carried out on methods of attaching an instrument for gas discharge to the surface of the cell. However, there has been a problem that deterioration of cell performance occurs due to leakage of the electrolyte at the seal site and penetration of moisture through the seal site during the attachment process of the instrument.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] One aspect of the present invention is to provide a pouch capable of discharging internal gas, a secondary battery including the same, and a method for manufacturing the same.

Means for Solving the Problems

[0008] The method for manufacturing a pouch according to an embodiment of the present invention is a method for manufacturing a pouch for a secondary battery, and may include a hole forming process of forming degassing holes in an aluminum sheet, and a lamination process of laminating a polymer layer on the aluminum sheet.

[0009] Further, the method for manufacturing a secondary battery according to an embodiment of the present invention may include a hole forming process of forming degassing holes in an aluminum sheet, a lamination process of laminating a polymer layer on the aluminum sheet to manufacture a pouch, an accommodation process of accommodating an electrode assembly in the pouch, and a sealing process of sealing the outer peripheral surface of the pouch.

[0010] Furthermore, the pouch according to an embodiment of the present invention is a pouch for accommodating an electrode assembly, the pouch including an aluminum sheet and a polymer layer laminated with the aluminum sheet, and degassing holes can be formed in the aluminum sheet.

[0011] On the other hand, the secondary battery according to an embodiment of the present invention includes an electrode assembly in which electrodes and separators are alternately laminated and bonded, and a pouch for accommodating the electrode assembly, the pouch including an aluminum sheet and a polymer layer laminated with the aluminum sheet, and degassing holes can be formed in the aluminum sheet.

Advantages of the Invention

[0012] According to the present invention, degassing holes are formed in the aluminum sheet of the pouch, a polymer layer is laminated on the aluminum sheet, and internal gas can permeate through the degassing holes and the polymer layer and be discharged to the outside.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0014] The objects, specific advantages, and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments, which are associated with the accompanying drawings. It should be noted that in this specification, when assigning reference numerals to the components of each drawing, as long as they are the same components, they should have the same number as much as possible when displayed on other drawings. Further, the present invention may be realized in various different forms and is not limited to the embodiments described herein. And when explaining the present invention, detailed descriptions of related known technologies that may unnecessarily obscure the gist of the present invention will be omitted.

[0015] Method for manufacturing a pouch FIG. 1 is a plan view showing the process of forming holes in a pouch and a method for manufacturing a secondary battery according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the lamination process in a pouch and a method for manufacturing a secondary battery according to an embodiment of the present invention.

[0016] Referring to FIGS. 1 and 2, a method for manufacturing a pouch according to an embodiment of the present invention is a method for manufacturing a pouch for a secondary battery that houses an electrode assembly, and includes a hole forming process of forming degassing holes 113a in an aluminum sheet 113, and a lamination process of laminating polymer layers 111 and 116 on the aluminum sheet 113 to manufacture a pouch 110.

[0017] More specifically, referring to FIG. 1, in the hole forming process, degassing holes 113a (degassing holes) can be formed in the aluminum sheet 113 (Aluminium Sheet).

[0018] Also, in the hole forming process, when the electrode assembly is housed, the degassing holes 113a can be formed so as to be located between the electrode assembly and the outer peripheral surface of the pouch 110. Furthermore, in the hole forming process, degassing holes 113a can be formed in the portion of the aluminum sheet 113 on the side where the electrode lead connected to the electrode assembly is located.

[0019] And in the process of forming the holes, degassing holes 113a can be formed to penetrate through the aluminum sheet 113 in a circular shape. At this time, in the process of forming the holes, degassing holes 113a can be formed in the aluminum sheet 113 with a size of 1 to 9 mm.

[0020] Referring to FIG. 2, in the lamination process, polymer layers 111 and 116 can be laminated on the aluminum sheet 113 to manufacture a pouch 110.

[0021] The polymer layers 111 and 116 can include a first polymer layer 116 and a second polymer layer 111. Here, in the lamination process, the first polymer layer 116 and the second polymer layer 111 can be formed on both sides of the aluminum sheet 113 to cover the degassing holes 113a formed in the aluminum sheet 113. At this time, the first polymer layer 116 and the second polymer layer 111 can include a polymer material. Thereby, the first polymer layer 116 and the second polymer layer 111 including a polymer material through which gases such as CO and CO2 can permeate cover the degassing holes 113a, enabling the discharge of internal gas and preventing the leakage of the electrolytic solution through the degassing holes 113a.

[0022] On the other hand, in the lamination process, after laminating the first polymer layer 116, the aluminum sheet 113, and the second polymer layer 111 from the inside to the outside where the electrode assembly is accommodated, lamination can be performed.

[0023] Here, in the lamination process, the first polymer layer 116, the aluminum sheet 113, and the second polymer layer 111 with thicknesses of 10 to 90 μm respectively can be laminated and laminated.

[0024] Furthermore, in the lamination process, a nylon layer 112 can be further laminated and laminated between the aluminum sheet 113 and the second polymer layer 111.

[0025] On the one hand, the second polymer layer 111 can be made of a PET (polyethylene terephthalate) material.

[0026] Also, as an example, the first polymer layer 116 can be made of a PP (polypropylene) material. Furthermore, as another example, in the first polymer layer 116, the inner layer 115 facing the electrode assembly can be made of a PP (polypropylene) material, and the outer layer 114 facing the aluminum sheet 113 can be made of a PPa (Polyphthalamide) material.

[0027] Method for manufacturing a secondary battery Hereinafter, a method for manufacturing a secondary battery according to an embodiment of the present invention will be described. FIG. 3 is a plan view showing a state before accommodating an electrode assembly in a pouch in the accommodating process of a method for manufacturing a secondary battery according to an embodiment of the present invention, FIG. 4 is a plan view showing a state where the electrode assembly is accommodated in the pouch in the accommodating process of a method for manufacturing a secondary battery according to an embodiment of the present invention, and FIG. 5 is a plan view showing a sealing process in a method for manufacturing a secondary battery according to an embodiment of the present invention.

[0028] Referring to FIGS. 1 to 5, a method for manufacturing a secondary battery according to an embodiment of the present invention includes a hole forming process of forming degassing holes 113a in the aluminum sheet 113, a lamination process of laminating the polymer layers 111 and 116 on the aluminum sheet 113 to manufacture the pouch 110, an accommodating process of accommodating the electrode assembly 120 in the pouch 110, and a sealing process of sealing the outer peripheral surface of the pouch 110, thereby manufacturing the secondary battery 100.

[0029] The method for manufacturing a secondary battery according to an embodiment of the present invention relates to a method for manufacturing a secondary battery that manufactures a secondary battery including a pouch manufactured by the method for manufacturing a pouch according to the above-described embodiment. Therefore, in this embodiment, the content overlapping with the above-described embodiment will be omitted or briefly described, and the description will focus on the differences.

[0030] More specifically, referring to FIG. 1, in the process of forming holes, degassing holes 113a can be formed in the aluminum sheet 113.

[0031] Also, in the process of forming holes, when the electrode assembly 120 is accommodated, the degassing holes 113a can be formed so as to be located between the electrode assembly 120 and the outer peripheral surface of the pouch 110.

[0032] Furthermore, in the process of forming holes, degassing holes 113a can be formed in the portion of the aluminum sheet 113 on the side where the electrode lead 130 is located. That is, the degassing holes 113a are located between the seal portion S formed on the outer peripheral surface of the aluminum sheet 113 and the electrode assembly 120 in the subsequent sealing process in the aluminum sheet 113, and can be formed on the side of the side where the electrode lead 130 is located among the four sides of the secondary battery 100 in a plan view (see FIGS. 3 and 5).

[0033] And, in the process of forming holes, the degassing holes 113a can be formed to penetrate the aluminum sheet 113 in a circular shape. At this time, in the process of forming holes, the degassing holes 113a can be formed in the aluminum sheet 113 to have a size of 1 to 9 mm.

[0034] Referring to FIG. 2, in the lamination process, the polymer layers 111 and 116 can be laminated on the aluminum sheet 113 to manufacture the pouch 110.

[0035] The polymer layers 111 and 116 can include a first polymer layer 116 and a second polymer layer 111. Here, in the lamination process, the first polymer layer 116 and the second polymer layer 111 can be formed on both sides of the aluminum sheet 113, and can cover the degassing holes 113a formed in the aluminum sheet 113. At this time, the first polymer layer 116 and the second polymer layer 111 can include a polymer material. Thereby, the first polymer layer 116 and the second polymer layer 111 including a polymer material through which gases such as CO and CO2 can permeate cover the degassing holes 113a, enabling the discharge of internal gas and preventing the leakage of the electrolytic solution through the degassing holes 113a.

[0036] On the other hand, in the lamination process, after laminating the first polymer layer 116, the aluminum sheet 113, and the second polymer layer 111 from the inside to the outside where the electrode assembly 120 is accommodated, lamination can be performed.

[0037] Here, in the lamination process, the first polymer layer 116, the aluminum sheet 113, and the second polymer layer 111 each having a thickness of 10 to 90 μm can be laminated and laminated.

[0038] Furthermore, in the lamination process, a nylon layer 112 can be further laminated and laminated between the aluminum sheet 113 and the second polymer layer 111.

[0039] On the other hand, the second polymer layer 111 can be made of a PET (polyethylene terephthalate) material.

[0040] Also, as an example, the first polymer layer 116 can be made of a PP (polypropylene) material. Furthermore, as another example, in the first polymer layer 116, the inner layer 115 facing the electrode assembly 120 can be made of PP (polypropylene) material, and the outer layer 114 facing the aluminum sheet 113 can be made of PPa (Polyphthalamide) material.

[0041] Referring to FIGS. 3 and 4, in the accommodating process, the electrode assembly 120 can be accommodated in the pouch 110. The electrode assembly 120 is a power generation element capable of charge and discharge, and can be formed in a form in which electrodes and separators are alternately laminated and bonded.

[0042] Furthermore, as an example, in the accommodating process, after placing the electrode assembly 120 on one side of the pouch 110, it can be covered on the other side to accommodate the electrode assembly 120. On the other hand, as another example, in the accommodating process, an accommodating portion for accommodating the electrode assembly 120 can be formed to accommodate the electrode assembly 120.

[0043] Also, in the accommodating process, the electrode lead 130 for connecting the electrode assembly 120 to an external device can be further accommodated. Here, one side of the electrode lead 130 is connected to the electrode of the electrode assembly 120 and accommodated inside the pouch 110, and the other side can extend outside the pouch 110 and be connected to an external device.

[0044] Referring to FIG. 5, in the sealing process, the outer peripheral surface of the pouch 110 can be sealed. Also, in the sealing step, the outer peripheral surfaces of three sides or four sides of the pouch 110 can be sealed to form a sealing portion S. And in the sealing step, heat can be applied to the outer peripheral surface of the pouch 110 from both sides and pressed to perform thermal fusion to form a sealing portion S.

[0045] Pouch Hereinafter, the pouch according to the embodiment of the present invention will be described. Referring to FIGS. 1 and 2, a pouch 110 according to an embodiment of the present invention is a pouch 110 that houses an electrode assembly 120. The pouch 110 includes an aluminum sheet 113 and polymer layers 111 and 116 laminated on the aluminum sheet 113, and degassing holes 113a are formed in the aluminum sheet 113 (see FIG. 3).

[0046] The pouch 110 according to an embodiment of the present invention relates to a pouch 110 manufactured by the method for manufacturing a pouch according to the foregoing embodiment. Therefore, in this embodiment, the content overlapping with the foregoing embodiment will be omitted or briefly described, and the description will focus on the differences.

[0047] More specifically, the pouch 110 can accommodate the electrode assembly 120. Here, in the pouch 110, a housing portion for accommodating the electrode assembly 120 can be formed inside.

[0048] At this time, the electrode assembly 120 accommodated in the pouch 110 is a power generation element capable of charging and discharging, and electrodes and separators are alternately laminated and bonded. The electrode assembly 120 can further include an electrode lead 130 connected to an end of the electrode. Here, through the electrode lead 130, the electrode assembly 120 can be electrically connected to an external device (see FIG. 3).

[0049] Also, the pouch 110 can include an aluminum sheet 113 and polymer layers 111 and 116 laminated on the aluminum sheet 113. The aluminum sheet 113 can be in the form of a sheet made of an aluminum material to form a layer.

[0050] And degassing holes 113a can be formed in the aluminum sheet 113. At this time, the degassing holes 113a can be formed in the aluminum sheet 113 to have a size of 1 to 9 mm.

[0051] Also, referring to FIGS. 1 to 3, the degassing hole 113a can be formed in the pouch 110 between the electrode assembly 120 and the outer peripheral surface of the pouch 110. Furthermore, the degassing hole 113a can be formed in the aluminum sheet 113 portion on the side where the electrode lead 130 is located.

[0052] The polymer layers 111 and 116 can include a first polymer layer 116 and a second polymer layer 111. Here, the first polymer layer 116 and the second polymer layer 111 are formed on both sides of the aluminum sheet 113 to cover the degassing hole 113a formed in the aluminum sheet 113. At this time, the first polymer layer 116 and the second polymer layer 111 can include a polymer material. Thereby, the first polymer layer 116 and the second polymer layer 111 including a polymer material through which gases such as CO and CO2 can permeate cover the degassing hole 113a, enabling the discharge of internal gas and preventing the leakage of the electrolytic solution through the degassing hole 113a.

[0053] The pouch 110 can have the first polymer layer 116, the aluminum sheet 113, and the second polymer layer 111 laminated from the inside where the electrode assembly 120 is accommodated to the outside. Here, the pouch 110 can have the first polymer layer 116, the aluminum sheet 113, and the second polymer layer 111, each having a thickness of 10 to 90 μm, laminated and joined. Also, the pouch 110 can have a nylon layer 112 further laminated between the aluminum sheet 113 and the second polymer layer 111.

[0054] On the other hand, the second polymer layer 111 can be made of a PET (polyethylene terephthalate) material.

[0055] Also, as an example, the first polymer layer 116 can be made of a PP (polypropylene) material. Furthermore, as another example, in the first polymer layer 116, the inner layer 115 facing the electrode assembly 120 can be made of PP (polypropylene), and the outer layer 114 facing the aluminum sheet 113 can be made of PPa (Polyphthalamide).

[0056] On the other hand, a seal portion S is formed on the outer peripheral surface of the pouch 110, and the inside of the pouch 110 can be sealed. At this time, the seal portion S can be formed by heat-sealing the outer peripheral surfaces of three sides or four sides of the pouch 110.

[0057] Secondary battery Hereinafter, the secondary battery according to the embodiment of the present invention will be described. Referring to FIGS. 1 to 5, the secondary battery 100 according to the embodiment of the present invention includes an electrode assembly 120 in which electrodes and separators are alternately stacked and joined, and a pouch 110 that houses the electrode assembly 120. The pouch 110 includes an aluminum sheet 113 and polymer layers 111 and 116 laminated on the aluminum sheet 113, and degassing holes 113a are formed in the aluminum sheet 113.

[0058] The secondary battery 100 according to the embodiment of the present invention relates to a secondary battery manufactured by the manufacturing method of the secondary battery according to the above-described embodiment. Therefore, in this embodiment, the content overlapping with the above-described embodiment will be omitted or briefly described, and the description will focus on the differences.

[0059] More specifically, in the secondary battery 100 according to the embodiment of the present invention, the electrode assembly 120 is a power generation element capable of charge and discharge, and electrodes and separators are alternately stacked and joined. Here, the electrodes include a positive electrode and a negative electrode, and the positive electrode, separator, and negative electrode can be alternately positioned.

[0060] Further, the electrode assembly 120 can further include an electrode lead 130 connected to the end of the electrode. Here, through the electrode lead 130, the electrode assembly 120 can be electrically connected to an external device.

[0061] The pouch 110 can accommodate the electrode assembly 120. Here, in the pouch 110, a housing portion for housing the electrode assembly 120 can be formed inside.

[0062] Further, the pouch 110 can include an aluminum sheet 113 and polymer layers 111 and 116 laminated to the aluminum sheet 113. The aluminum sheet 113 can be in the form of a sheet made of an aluminum material to form a layer.

[0063] And, degassing holes 113a can be formed in the aluminum sheet 113. At this time, the degassing holes 113a can be formed in the aluminum sheet 113 with a size of 1 to 9 mm.

[0064] Further, the degassing holes 113a can be formed between the electrode assembly 120 and the outer peripheral surface of the pouch 110 in the pouch 110. Furthermore, the degassing holes 113a can be formed in the portion of the aluminum sheet 113 on the side where the electrode lead 130 is located.

[0065] The polymer layers 111 and 116 can include a first polymer layer 116 and a second polymer layer 111. Here, the first polymer layer 116 and the second polymer layer 111 can be formed on both sides of the aluminum sheet 113, and can cover the degassing holes 113a formed in the aluminum sheet 113. At this time, the first polymer layer 116 and the second polymer layer 111 can include a polymer material. Thereby, the first polymer layer 116 and the second polymer layer 111 including a polymer material through which gases such as CO and CO2 can permeate cover the degassing holes 113a, enabling the discharge of internal gas and preventing the leakage of the electrolytic solution through the degassing holes 113a.

[0066] The pouch 110 can have the first polymer layer 116, the aluminum sheet 113, and the second polymer layer 111 laminated from the inside to the outside where the electrode assembly 120 is accommodated. Here, the pouch 110 can have the first polymer layer 116, the aluminum sheet 113, and the second polymer layer 111, each having a thickness of 10 to 90 μm, laminated and joined. Also, the pouch 110 can further have a nylon layer 112 laminated between the aluminum sheet 113 and the second polymer layer 111.

[0067] On the other hand, the second polymer layer 111 can be made of PET (polyethylene terephthalate) material.

[0068] Also, as an example, the first polymer layer 116 can be made of PP (polypropylene) material. Furthermore, as another example, in the first polymer layer 116, the inner layer 115 facing the electrode assembly 120 can be made of PP (polypropylene) material, and the outer layer 114 facing the aluminum sheet 113 can be made of PPa (Polyphthalamide) material.

[0069] On one hand, a seal portion S is formed on the outer peripheral surface of the pouch 110, and the inside of the pouch 110 can be sealed. At this time, the seal portion S can be formed by heat-sealing the outer peripheral surfaces of three sides or four sides of the pouch 110.

[0070] As described above, the present invention has been described in detail with reference to specific embodiments, but this is for specifically explaining the present invention and the present invention is not limited thereto. It can be said that various implementations are possible by those having ordinary knowledge in the art within the technical idea of the present invention. Also, the specific protection scope of the invention will be clarified by the appended claims.

Explanation of Reference Numerals

[0071] 100: Secondary battery 110: Pouch 111: Second polymer layer 112: Nylon layer 113: Aluminum sheet 113a: Degassing hole 116: First polymer layer 120: Electrode assembly 130: Electrode lead S: Seal portion

Claims

1. A method for manufacturing a pouch for a secondary battery that houses an electrode assembly body, comprising: a pore formation process of forming degassing pores in an aluminum sheet; a lamination process of laminating a polymer layer on the aluminum sheet; and in the pore formation process, a method for manufacturing a pouch, which is formed such that when the electrode assembly body is housed, the degassing pores are positioned between the electrode assembly body and a seal portion formed on an outer peripheral surface of the pouch.

2. The polymer layer includes a first polymer layer and a second polymer layer, and the lamination process is a lamination process of laminating the first polymer layer, the aluminum sheet, and the second polymer layer from the inside to the outside where the electrode assembly body is housed and then laminating, according to the method for manufacturing a pouch described in Claim 1.

3. a pore formation process of forming degassing pores in an aluminum sheet; a lamination process of laminating a polymer layer on the aluminum sheet to manufacture a pouch; a housing process of housing an electrode assembly body in the pouch; a sealing process of sealing an outer peripheral surface of the pouch; and in the pore formation process, a method for manufacturing a secondary battery, which is formed such that when the electrode assembly body is housed, the degassing pores are positioned between the electrode assembly body and a seal portion formed on an outer peripheral surface of the pouch.

4. The polymer layer includes a first polymer layer and a second polymer layer, and the lamination process is a lamination process of laminating the first polymer layer, the aluminum sheet, and the second polymer layer from the inside to the outside where the electrode assembly body is housed and then laminating, according to the method for manufacturing a secondary battery described in Claim 3.

5. The first polymer layer is made of a PP (polypropylene) material, and the second polymer layer is made of a PET (polyethylene terephthalate) material, according to the method for manufacturing a secondary battery described in Claim 4.

6. In the first polymer layer, the inner layer facing the electrode assembly body is made of a PP (polypropylene) material, and the outer layer facing the aluminum sheet is made of a PPa (Polyphtalamide) material. The manufacturing method of the secondary battery according to claim 4, wherein the second polymer layer is made of a PET (polyethylene terephthalate) material.

7. The lamination process is The manufacturing method of the secondary battery according to any one of claims 4 to 6, wherein a nylon layer is further laminated and laminated between the aluminum sheet and the second polymer layer.

8. In the accommodating process, an electrode lead for connecting the electrode assembly to an external device is further accommodated, The manufacturing method of the secondary battery according to any one of claims 3 to 7, wherein the degassing holes are formed in the aluminum sheet portion on the side where the electrode lead is located in the hole forming process.

9. A pouch for accommodating an electrode assembly, The pouch includes an aluminum sheet and a polymer layer laminated with the aluminum sheet, In the aluminum sheet, when the electrode assembly is accommodated, degassing holes are formed so as to be located between the electrode assembly and a seal portion formed on the outer peripheral surface of the pouch, Among the aluminum sheet and the polymer layer, the degassing holes are formed only in the aluminum sheet, The pouch in which the polymer layer is laminated on the aluminum sheet so as to cover the degassing holes.

10. The polymer layer includes a first polymer layer and a second polymer layer, The pouch according to claim 9, wherein the first polymer layer, the aluminum sheet, and the second polymer layer are laminated from the inside to the outside where the electrode assembly is accommodated.

11. An electrode assembly in which electrodes and separators are alternately laminated and bonded, A pouch for accommodating the electrode assembly, Including, The pouch includes an aluminum sheet and a polymer layer laminated with the aluminum sheet, Degassing holes are formed in the aluminum sheet, The degassing holes are In the pouch, they are formed between the electrode assembly and a seal portion formed on the outer peripheral surface of the pouch, Among the aluminum sheet and the polymer layer, the degassing holes are formed only in the aluminum sheet, The secondary battery in which the polymer layer is laminated on the aluminum sheet so as to cover the degassing holes.

12. The polymer layer includes a first polymer layer and a second polymer layer, The secondary battery according to claim 11, wherein the pouch has the first polymer layer, the aluminum sheet, and the second polymer layer laminated in that order from the inside where the electrode assembly is accommodated to the outside.

13. The secondary battery according to claim 12, wherein the first polymer layer is made of a PP (polypropylene) material, and the second polymer layer is made of a PET (polyethylene terephthalate) material.

14. In the first polymer layer, the inner layer facing the electrode assembly is made of a PP (polypropylene) material, and the outer layer facing the aluminum sheet is made of a PPa (Polyphthalamide) material. The secondary battery according to claim 12, wherein the second polymer layer is made of a PET (polyethylene terephthalate) material.

15. The pouch The secondary battery according to any one of claims 12 to 14, wherein a nylon layer is further laminated between the aluminum sheet and the second polymer layer.

16. The secondary battery further includes an electrode lead for connecting the electrode assembly to an external device. The secondary battery according to any one of claims 11 to 15, wherein the degassing hole is formed in the portion of the aluminum sheet on the side where the electrode lead is located.

Images