Pouch cell

Abstract

The present invention relates to a pouch cell which can prevent moisture and the like from the outside of a pouch from penetrating into the pouch through a portion where gas inside the pouch is discharged to the outside, or can reduce the penetration. The pouch cell according to the present invention comprises: an electrode assembly including a positive electrode, a negative electrode, and a separator; a pouch which accommodates the electrode assembly therein and has a hole formed therein; and a gas discharge film which is attached to the pouch to cover the hole and allows gas to pass therethrough. The pouch comprises a discharge portion having the hole formed therein, and an exterior portion connected to the discharge portion, and the discharge portion and the exterior portion may have a stepped shape with respect to each other.

Description

pouch cell

[0001] [Cross-reference with related applications]

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0105070, filed August 10, 2023, the entire contents of which are incorporated herein by reference.

[0003] [Technical Field]

[0004] The present invention relates to a pouch cell, and more specifically, to a secondary battery pouch cell capable of being charged and discharged.

[0005] In recent years, rising energy prices due to the depletion of fossil fuels and growing concerns about environmental pollution have made the demand for eco-friendly alternative energy sources essential for future living. Research is continuing into various power generation technologies, such as solar, wind, and tidal power. Furthermore, significant interest is being focused on power storage devices, such as batteries, to more efficiently utilize the generated electricity.

[0006] Moreover, with the technological development and increasing demand for battery-powered electronic mobile devices and electric vehicles, the demand for batteries as an energy source is rapidly increasing, and accordingly, much research is being conducted on batteries that can meet various needs.

[0007] Batteries that store electrical energy can generally be divided into primary and secondary batteries. Primary batteries are disposable, consumable batteries, whereas secondary batteries are rechargeable batteries manufactured using materials capable of repeatable oxidation and reduction processes between current and a substance. In other words, when current causes a reduction reaction in a material, the battery is charged, and when an oxidation reaction occurs in the material, the battery is discharged. This repeated charge-discharge cycle generates electricity.

[0008] Secondary batteries can be classified into cylindrical cells, pouch cells, and prismatic cells based on their shape. Among them, pouch cells can be manufactured by housing an electrode assembly in which a positive electrode, a negative electrode, a separator, etc. are laminated inside a pouch, and sealing the outer part of the pouch.

[0009] Meanwhile, an electrolyte may be accommodated inside the pouch of the pouch cell together with an electrode assembly. At this time, residual moisture in the electrolyte or moisture that has penetrated from the outside may react with the lithium salt inside the pouch of the pouch cell to generate HF (hydrogen fluoride), and gases such as carbon dioxide, carbon monoxide, ethylene, and methane may be generated due to the decomposition of the electrolyte. In addition, depending on the material of the positive electrode included in the electrode assembly of the pouch cell, additional hydrogen and HF may be generated, which may lead to overheating due to overcharging and internal short circuit during the charging and discharging process. As a result, a large amount of gas may be generated inside the pouch. This gas may increase the pressure inside the pouch, and the increased pressure may cause a swelling phenomenon in which the pouch swells or a venting phenomenon in which a portion of the pouch bursts. Therefore, the pouch cell may include a structure capable of discharging the gas inside the pouch to the outside to prevent the venting phenomenon.

[0010] Pouch cells including conventional gas discharge structures had a problem in that external moisture, etc., entered the interior of the pouch through the gas discharge structure, and additional problems such as a decrease in the performance of the pouch cell occurred due to the infiltration of moisture, etc.

[0011] Therefore, there is a need for a pouch cell that can prevent or reduce moisture from the outside of the pouch from penetrating into the inside of the pouch through a portion where gas inside the pouch is discharged to the outside.

[0012] The object of the present invention is to provide a pouch cell capable of preventing or reducing moisture or the like from outside the pouch from penetrating into the interior of the pouch through a portion through which gas inside the pouch is discharged to the outside.

[0013] A pouch cell according to the present invention comprises an electrode assembly including a positive electrode, a negative electrode, and a separator, a pouch accommodating the electrode assembly therein and having a hole formed therein, and a gas discharge film attached to the pouch to cover the hole and allowing gas to pass therethrough, wherein the pouch comprises a discharge portion having the hole formed therein, and an outer portion connected to the discharge portion, wherein the discharge portion and the outer portion may have a stepped shape relative to each other.

[0014] The above discharge portion may have a stepped shape in a direction away from the electrode assembly.

[0015] The above gas discharge film can be placed between the pouch and the electrode assembly.

[0016] The above gas discharge film may include a first film portion attached to the discharge portion and covering the hole, and a second film portion attached to the outer portion and having a stepped shape with respect to the first film portion.

[0017] The above gas discharge film may have the first film portion and the second film portion having the same thickness.

[0018] The above gas discharge film may have a thickness from the discharge portion to one side that is thicker than the thickness from the outer portion to the one side.

[0019] The above discharge portion may have a stepped shape in the direction toward the electrode assembly.

[0020] The above gas discharge film can be combined with both one side of the discharge portion and one side of a portion of the outer portion.

[0021] The above pouch may have a surface roughness of a side facing the gas discharge film that is greater than a surface roughness of a side not facing the gas discharge film.

[0022] The above pouch may be plasma treated or primer treated so that the surface roughness of one side facing the gas discharge film is greater than the surface roughness of one side not facing the gas discharge film.

[0023] The above pouch may have a surface roughness (R) of 20 nm or more and 140 nm or less on one side facing the gas discharge film.

[0024] The above pouch may further include a sealing portion sealed by a seal, and the discharge portion may be arranged to have a gap from the sealing portion.

[0025] A pouch cell according to the present invention comprises an electrode assembly including a positive electrode, a negative electrode, and a separator, a pouch accommodating the electrode assembly therein and having a hole formed therein, and a gas discharge film attached to the pouch to cover the hole and allowing gas to pass therethrough, wherein the pouch comprises a discharge portion having the hole formed therein, and an outer portion connected to the discharge portion, wherein the discharge portion and the outer portion may have a stepped shape relative to each other.

[0026] Accordingly, it is possible to discharge gas inside the pouch to the outside while simultaneously preventing moisture, etc., from outside the pouch from flowing into the inside of the pouch.

[0027] Through this, the functional degradation of the pouch cell can be prevented.

[0028] Additionally, the safety of the pouch cell can be improved by delaying or preventing venting of the pouch caused by gas inside the pouch.

[0029] The effects according to the present invention are not limited to the contents exemplified above, and more diverse effects are included in this specification.

[0030] FIG. 1 is a perspective view schematically illustrating a pouch cell according to Example 1 of the present invention.

[0031] Fig. 2 is a cross-sectional view schematically illustrating a portion of a cross-section taken along line A-A' of Fig. 1.

[0032] Figure 3 is an enlarged view schematically illustrating part B of Figure 2.

[0033] FIG. 4 is an enlarged view schematically illustrating a gas discharge film and its surroundings of a pouch cell according to Example 2 of the present invention.

[0034] FIG. 5 is an enlarged view schematically illustrating a gas discharge film and its surroundings of a pouch cell according to Example 3 of the present invention.

[0035] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0036] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0037] In addition, terms or words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0038] Example 1

[0039] Figure 1 is a perspective view schematically illustrating a pouch cell (10) according to Example 1 of the present invention.

[0040] A pouch cell (10) according to Example 1 of the present invention may include an electrode assembly (100), a pouch (200), and a gas discharge film (300).

[0041] The pouch cell (10) according to the present invention may refer to a pouch-type secondary battery among various types of secondary batteries capable of being charged and discharged. The pouch cell (10) may have a form in which an electrode assembly (100) is accommodated inside a pouch (200).

[0042] The electrode assembly (100) may include an anode, a cathode, and a separator. Here, the separator may be positioned between the anode and the cathode to physically separate the anode and the cathode. The electrode assembly (100) may be in a stacked form in which the anode, the cathode, and the separator are laminated, or in a jelly-roll form in which the anode, the cathode, and the separator are wound.

[0043] The electrode assembly (100) may be accommodated inside a pouch (200). The pouch (200) may include an inner layer, a metal layer, and an outer layer, and the inner layer may have sealing properties due to heat and pressure. After the pouch (200) accommodates the electrode assembly (100) inside, the inner layer may be sealed by heat and pressure. The metal layer may mainly be made of Al, STS, or the like. In addition, the outer layer may have insulating properties.

[0044] The inner layer capable of sealing the pouch (200) through sealing may be made of one or more materials selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymers, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, polyparaphenylene benzobisoxazole, polyarylate, Teflon, and glass fiber. In particular, a polyolefin resin such as polypropylene (PP) or polyethylene (PE) may be mainly used.

[0045] The pouch cell (10) may include an electrode lead (400). The electrode lead (400) may be electrically connected to the electrode assembly (100) and may be arranged to protrude outside the pouch (200). The pouch cell (10) may provide electrical energy to the outside by the electrode lead (400) protruding outside the pouch (200). Therefore, the electrode lead (400) may be a conductor.

[0046] The lead film may cover the electrode lead (400) so that the pouch (200) and the electrode lead (400) are insulated from each other. Specifically, the lead film may be placed on both sides of the electrode lead (400) to cover the electrode lead (400). The lead films may be configured as a pair and may be placed on each side of the electrode lead (400).

[0047] The pouch (200) may further include a sealing portion (230). The sealing portion (230) may refer to a portion sealed by heat and pressure. Specifically, the sealing portion (230) may include a portion from which the electrode lead (400) protrudes. The portion of the sealing portion (230) from which the electrode lead (400) protrudes may be sealed with a lead film. In addition, the portion of the sealing portion (230) from which the electrode lead (400) does not protrude may be sealed to each other by opposing pouches (200).

[0048] Meanwhile, as the pouch cell (10) is repeatedly charged and discharged, gas may be generated, which may increase the pressure inside the pouch (200). If the pressure inside the pouch (200) increases excessively, a venting phenomenon, etc. may occur, causing the pouch cell (10) to lose its function.

[0049] Specifically, an electrolyte may be accommodated together with an electrode assembly (100) inside the pouch (200) of the pouch cell (10). At this time, residual moisture of the electrolyte or moisture that has penetrated from the outside may react with a lithium salt inside the pouch (200) of the pouch cell (10) to generate HF, and gases such as carbon dioxide, carbon monoxide, ethylene, and methane may be generated due to decomposition of the electrolyte. In addition, depending on the material of the positive electrode included in the electrode assembly (100) of the pouch cell (10), hydrogen and HF may be additionally generated, which may cause overheating due to overcharging and internal short circuit during the charging and discharging process. Accordingly, a large amount of gas may be generated inside the pouch (200). The pressure inside the pouch may increase due to such gas, and the increased pressure may cause a swelling phenomenon in which the pouch (200) swells or a venting phenomenon in which a portion of the pouch (200) bursts.

[0050] The pouch cell (10) according to Example 1 of the present invention may include a configuration capable of discharging gas inside the pouch (200) to the outside of the pouch (200) to prevent a venting phenomenon from occurring.

[0051] Fig. 2 is a cross-sectional view schematically illustrating a portion of a cross-section cut along line A-A' of Fig. 1, and Fig. 3 is an enlarged view schematically illustrating part B of Fig. 2.

[0052] Referring to FIG. 2, a pouch (200) of a pouch cell (10) according to Example 1 of the present invention may have a hole (211) formed in a portion thereof. In addition, the pouch cell (10) may include a gas discharge film (300) disposed in a portion of the pouch (200) where the hole (211) is formed.

[0053] The pouch (200) of the pouch cell (10) may include a discharge portion (210) and an outer portion (220). The discharge portion (210) of the pouch (200) may be a portion where a hole (211) is formed. The outer portion (220) of the pouch (200) may refer to another portion that is connected to the discharge portion (210) and where a hole (211) is not formed.

[0054] A hole (211) may be formed in the discharge portion (210) with a circular cross-section. This is merely an example, and the hole (211) may be formed in other shapes. In addition, although the present invention exemplifies a case where one hole (211) is formed in the pouch (200), a plurality of holes (211) may be formed in the pouch (200).

[0055] Meanwhile, the discharge portion (210) according to Embodiment 1 of the present invention may be arranged to have a gap with the sealing portion (230). Specifically, the pouch (200) may include a cup portion formed in a concave shape for arranging the electrode assembly (100). The cup portion may include a surface on which the electrode assembly (100) is placed and a surface that is bent from the surface to form a border. Here, the discharge portion (210) may be formed on the surface that forms the border. Accordingly, the discharge portion (210) may be arranged to be spaced apart from the electrode assembly (100), and gas inside the pouch (200) may be discharged to the outside of the pouch (200) more efficiently through the hole (211). In addition to the position of the discharge portion (210) described in the present invention, the position of the discharge portion (210) in which the hole (211) is formed may vary.

[0056] The gas discharge film (300) of the pouch cell (10) is attached to the pouch (200) so as to cover the hole (211) formed in the pouch (200), and gas can be permeated therethrough. Specifically, gas generated inside the pouch (200) can permeate the gas discharge film (300), pass through the hole (211), and be discharged to the outside of the pouch (200).

[0057] The gas discharge film (300) may include a material that allows gas to be discharged but does not allow liquid to pass through. The gas discharge film (300) may have higher gas permeability than the pouch (200). For example, the gas discharge film (300) may include a fluorine-based resin. Specifically, the gas discharge film (300) may be made of PTFE (Polytetrafluoroethylene).

[0058] The pouch cell (10) enables efficient gas discharge through the penetration of the gas discharge film (300).

[0059] Since the discharge portion (210) of the pouch (200) has a hole (211) that extends from the inside to the outside of the pouch (200), foreign substances such as moisture may infiltrate into the interior of the pouch (200) through the hole (211). If foreign substances such as moisture infiltrate into the interior of the pouch (200), the performance of the pouch cell (10) may deteriorate, and there is a risk that the pouch cell (10) may not function properly. Therefore, a configuration capable of preventing moisture from infiltrating into the interior of the pouch (200) is required.

[0060] As an example of a configuration for preventing moisture, etc. from penetrating into the pouch (200), the pouch (200) of the pouch cell (10) according to Embodiment 1 of the present invention may have a shape in which the discharge portion (210) and the outer portion (220) are stepped from each other. Specifically, the discharge portion (210) may have a shape in which the discharge portion (210) is stepped in a direction away from the electrode assembly (100) arranged inside the pouch (200). Accordingly, the discharge portion (210) may be arranged farther away from the electrode assembly (100) than the outer portion (220).

[0061] The gas discharge film (300) of the pouch cell (10) can be placed between the pouch (200) and the electrode assembly (100). That is, the gas discharge film (300) can be bonded to the inner surface of the pouch (200). Accordingly, a longer path can be formed between the pouch (200) and the gas discharge film (300) through which moisture can penetrate.

[0062] Meanwhile, since the discharge portion (210) and the outer portion (220) have a stepped shape, the area where the gas discharge film (300) is combined with the pouch (200) can increase. Referring to FIG. 3, a portion where the discharge portion (210) and the outer portion (220) are connected is created due to the stepped shape, and the gas discharge film (300) can be additionally combined with this portion. Here, the pouch (200) and the gas discharge film (300) can be combined through sealing by heat and pressure. This is only one example, and the pouch (200) and the gas discharge film (300) may be combined in other ways. Since the area where the gas discharge film (300) is combined with the pouch (200) increases, moisture penetration into the interior of the pouch (200) can become more difficult.

[0063] Referring to FIG. 3, the gas discharge film (300) may be formed so that the thickness (T1) from the discharge portion (210) to one side is thicker than the thickness (T2) from the outer portion (220) to one side. At this time, the one side of the gas discharge film (300) may mean the side facing the electrode assembly (100). Preferably, the gas discharge film (300) may have a shape corresponding to the discharge portion (210) and the outer portion (220) so that it can be combined with both the inner surface of the pouch (200) facing the gas discharge film (300).

[0064] Since the discharge portion (210) and the outer portion (220) of the pouch (200) have a stepped shape, the path through which moisture can permeate from the outside of the pouch (200) to the inside of the pouch (200) may be longer than when the shape is not stepped. That is, the area of ​​the portion where the pouch (200) and the gas discharge film (300) are sealed to each other by sealing or the like may be widened. Therefore, since the path through which moisture can permeate is longer, it may become more difficult for moisture to permeate the pouch (200). For reference, in FIG. 3, the path through which moisture can permeate into the inside of the pouch (200) is indicated by an arrow.

[0065] The pouch cell (10) according to Example 1 of the present invention can prevent foreign substances such as moisture from penetrating into the interior of the pouch (200) through the hole (211) formed in the pouch (200). Accordingly, it is possible to discharge gas inside the pouch (200) while delaying or preventing deterioration in the performance of the pouch cell (10).

[0066] Example 2

[0067] FIG. 4 is an enlarged view schematically illustrating a gas discharge film (300) and its surroundings of a pouch cell (10) according to Example 2 of the present invention.

[0068] Hereinafter, a detailed description of the same configuration as that of the pouch cell (10) according to Example 1 of the present invention will be omitted, and the differences will be mainly described.

[0069] The pouch cell (10) according to Example 2 of the present invention may have different shapes of the pouch (200) and the gas discharge film (300) from the pouch cell (10) according to Example 1 of the present invention.

[0070] The pouch (200) of the pouch cell (10) according to Example 2 of the present invention may include a discharge portion (210) in which a hole (211) is formed and an outer portion (220) having a stepped shape with respect to the discharge portion (210). In this case, the discharge portion (210) may have a stepped shape in a direction away from the electrode assembly (100) accommodated inside the pouch (200).

[0071] Referring to FIG. 4, the gas discharge film (300) of the pouch cell (10) may include a first film portion (310) and a second film portion (320). Specifically, the first film portion (310) may be attached to the discharge portion (210) of the pouch (200) to cover the hole (211). In addition, the second film portion (320) may be attached to the outer portion (220) of the pouch (200) and may have a stepped shape with respect to the first film portion (310). More specifically, the first film portion (310) and the second film portion (320) of the gas discharge film (300) may have a stepped shape so as to correspond to the stepped shapes of the discharge portion (210) and the outer portion (220) of the pouch (200).

[0072] Meanwhile, the first film portion (310) and the second film portion (320) of the gas discharge film (300) may have the same thickness. That is, the thickness of the portion covering the hole (211) in the gas discharge film (300) may be formed relatively thinner compared to Example 1. Accordingly, gas inside the pouch (200) can easily permeate through the gas discharge film (300), making gas discharge more efficient.

[0073] As an example of a configuration for effectively preventing moisture from penetrating into the interior of the pouch (200), the pouch (200) of the pouch cell (10) according to Embodiment 2 of the present invention may have one surface treated. Specifically, the pouch (200) may be formed such that the surface roughness of the one surface facing the gas discharge film (300) is greater than the surface roughness of the one surface not facing the gas discharge film (300). More specifically, the pouch (200) may have a surface roughness (R) of 20 nm or more and 140 nm or less of the one surface facing the gas discharge film (300). Here, the one surface of the pouch (200) may mean the inner surface facing the electrode assembly (100).

[0074] One side of the pouch (200) facing the gas discharge film (300) can be a path for moisture to penetrate from the outside of the pouch (200) into the inside of the pouch (200). That is, since the surface roughness of the side that can be a moisture penetration path is relatively large, the hydrophobicity can be relatively large. Accordingly, moisture penetration into the inside of the pouch (200) can be prevented or the amount of moisture penetration can be reduced.

[0075] As an example of surface treatment of one side of the pouch (200) facing the gas discharge film (300), plasma treatment or primer treatment is possible. In this case, plasma treatment may mean that the shape of the surface is changed by plasma contacting the object and applying energy to the surface. In addition, primer treatment may mean treating the object with a primer.

[0076] In the pouch cell (10) according to Example 2 of the present invention, a case in which a portion of the pouch (200) has a large surface roughness has been described as an example, but other cases in which hydrophobicity can be increased are also possible. For example, one side of the pouch (200) facing the gas discharge film (300) may be coated with a fluorine-based resin. In this case, additional configuration may be required to strengthen the adhesion between the pouch (200) and the film (300).

[0077] In Fig. 4, the path through which moisture can penetrate into the interior of the pouch (200) is indicated by arrows. Referring to Fig. 4, the path through which moisture penetrates into the interior of the pouch (200) may have a relatively large surface roughness. Accordingly, the hydrophobicity of the path through which moisture penetrates into the interior of the pouch (200) increases, thereby more effectively preventing moisture penetration.

[0078] Example 3

[0079] FIG. 5 is an enlarged view schematically illustrating a gas discharge film (300) and its surroundings of a pouch cell (10) according to Example 3 of the present invention.

[0080] The pouch cell (10) according to Example 3 of the present invention may be different from Examples 1 and 2 in the shape of the pouch (200) and the shape of the gas discharge film (300).

[0081] The pouch (200) of the pouch cell (10) according to Example 3 of the present invention may include a discharge portion (210) and an outer portion (220). A hole (211) may be formed in the discharge portion (210), and the outer portion (220) may be connected to the discharge portion (210). In addition, a gas discharge film (300) may be combined with the pouch (200) to cover the hole (211) formed in the discharge portion (210). At this time, the gas discharge film (300) may be placed between the pouch (200) and the electrode assembly (100).

[0082] Referring to FIG. 5, the discharge portion (210) of the pouch (200) according to Example 3 of the present invention may have a stepped shape with respect to the outer portion (220). Specifically, the discharge portion (210) may have a stepped shape in the direction toward the electrode assembly (100). Accordingly, the gap between the discharge portion (210) and the electrode assembly (100) may be shorter than the gap between the outer portion (220) and the electrode assembly (100).

[0083] The gas discharge film (300) can be combined with one side of the pouch (200). Specifically, the gas discharge film (300) can be combined with both one side (S1) of the discharge portion (210) and one side (S2) of the outer portion (220). Therefore, the thickness of the gas discharge film (300) at the portion combined with the discharge portion (210) can be thinner than the thickness of the portion combined with the outer portion (220).

[0084] In Fig. 5, a path through which moisture can penetrate into the interior of the pouch (200) is indicated by arrows. Referring to Fig. 5, the gas discharge film (300) may include a folded portion due to the step between the discharge portion (210) and the outer portion (220). When moisture penetrates into the interior of the pouch (200), the moisture penetration may be relatively difficult due to the folded portion of the gas discharge film (300). Therefore, the pouch cell (10) according to Example 3 of the present invention can effectively prevent moisture from penetrating into the interior of the pouch (200) through the hole (211).

[0085] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. An electrode assembly including a positive electrode, a negative electrode, and a separator; A pouch having a hole formed therein and housing the electrode assembly; and It is attached to the pouch to cover the hole and includes a gas-permeable gas-exhausting film, The above pouch is, an exhaust portion in which the above hole is formed; and Includes an external part connected to the above discharge part, A pouch cell, wherein the discharge portion and the outer portion have a stepped shape relative to each other.

2. In paragraph 1, The above discharge part, A pouch cell having a stepped shape in a direction away from the electrode assembly.

3. In paragraph 1, The above gas discharge film, A pouch cell disposed between the pouch and the electrode assembly.

4. In paragraph 1, The above gas discharge film, A first film portion attached to the discharge portion and covering the hole; and A pouch cell attached to the outer portion and including a second film portion having a stepped shape with the first film portion.

5. In paragraph 4, The above gas discharge film, A pouch cell, wherein the first film portion and the second film portion have the same thickness.

6. In paragraph 4, The above gas discharge film, A pouch cell, wherein the thickness from the discharge portion to one side is thicker than the thickness from the outer portion to the one side.

7. In paragraph 1, The above discharge part, A pouch cell having a stepped shape in the direction toward the electrode assembly.

8. In paragraph 7, The above gas discharge film, A pouch cell that is connected to both one side of the above discharge portion and one side of a portion of the above outer portion.

9. In paragraph 1, The above pouch is, A pouch cell, wherein the surface roughness of one side facing the gas discharge film is greater than the surface roughness of one side not facing the gas discharge film.

10. In paragraph 1, The above pouch is, A pouch cell that is plasma treated or primer treated so that the surface roughness of one side facing the gas discharge film is greater than the surface roughness of one side not facing the gas discharge film.

11. In paragraph 1, The above pouch is, A pouch cell having a surface roughness (R) of 20 nm or more and 140 nm or less on one side facing the gas discharge film.

12. In paragraph 1, The above pouch is, Further comprising a sealing portion sealed by a sealing member, A pouch cell in which the discharge portion is arranged to have a gap with the sealing portion.

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