Pouch cell and gas discharge member

Abstract

The purpose of the present invention is to provide a gas discharge member capable of discharging gas inside a pouch to the outside and having reduced strain, and a pouch cell including same. The pouch cell according to the present invention may comprise: an electrode assembly including a positive electrode, a negative electrode, and a separator; a pouch that accommodates the electrode assembly; an electrode lead electrically connected to the electrode assembly and protruding to the outside of the pouch; a lead film covering a part of the electrode lead so that the electrode lead is insulated from the pouch; and a gas discharge member disposed between the electrode lead and the lead film and provided so that a gas movement path is formed by means of gas inside the pouch, wherein the gas discharge member may comprise: a first member having a partially concave shape with respect to the longitudinal direction of the electrode lead; and a second member extending from the first member toward the electrode assembly.

Description

Pouch cell and gas venting member

[0001] [Cross-reference with related applications]

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2023-0105932, filed August 11, 2023, the entire disclosure of which is incorporated herein by reference.

[0003] [Technical Field]

[0004] The present invention relates to a pouch cell and a gas discharge member, and more specifically, to a secondary battery pouch cell capable of being charged and discharged and a gas discharge member for discharging gas inside the pouch cell.

[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 the pouch to swell, 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] Conventional pouch cells had a problem in that part of the gas discharge member was deformed due to the pressure of the gas inside the pouch.

[0011] Therefore, there is a need for a gas discharge member and a pouch cell including the same that can reduce the degree of deformation of a portion of a high-strain gas discharge member.

[0012] 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.

[0013] 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.

[0014] The object of the present invention is to provide a gas discharge member capable of discharging gas inside a pouch to the outside and having a reduced strain rate, and a pouch cell including the same.

[0015] 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; an electrode lead electrically connected to the electrode assembly and protruding outside the pouch; a lead film covering a portion of the electrode lead so as to insulate the electrode lead from the pouch; and a gas exhaust member disposed between the electrode lead and the lead film and provided so as to form a gas movement path by a gas inside the pouch; wherein the gas exhaust member may include a first member having a partially concave shape with respect to a longitudinal direction of the electrode lead, and a second member extending from the first member toward the electrode assembly.

[0016] The above first member may have a concave shape formed on the electrode assembly side with respect to the longitudinal direction of the electrode lead.

[0017] The first member may have a concave shape formed on the opposite side of the electrode assembly with respect to the longitudinal direction of the electrode lead.

[0018] The above first member may have a concave shape including a curve.

[0019] The above first member may have a concave shape including a plurality of line segments that are connected to each other at obtuse angles.

[0020] The first member may have a width narrower than the width of the second member.

[0021] The first member may include a first extension portion extending in the width direction of the electrode lead, and a second extension portion connected to the first extension portion and extending obliquely with respect to the width direction of the electrode lead.

[0022] The first extension portion may have a width wider than the second extension portion.

[0023] The first member may be formed such that the length in the width direction of the electrode lead is less than or equal to the width of the electrode lead.

[0024] The above gas discharge member may be provided with a lower adhesive strength with the lead film than with the electrode lead.

[0025] The above gas discharge member may include PTFE.

[0026] 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; an electrode lead electrically connected to the electrode assembly and protruding outside the pouch; a lead film covering a portion of the electrode lead so as to insulate the electrode lead from the pouch; and a gas discharge member disposed between the electrode lead and the lead film, the gas discharge member being arranged to form a gas movement path by a gas inside the pouch, wherein the distance from a reference line extending in the width direction of the electrode lead between an outer end of the pouch and an outer end of the lead film to the outer end of the gas discharge member may be variable.

[0027] A gas discharge member according to the present invention may include a first member having a partially concave shape, and a second member connected to the first member and extending in a direction away from the first member.

[0028] The above first member may have a concave shape formed on both sides with respect to the direction perpendicular to the extension direction.

[0029] The above first member may have a concave shape including a plurality of line segments that are connected to each other at obtuse angles.

[0030] According to a preferred embodiment of the present invention, gas generated inside the pouch during charging and discharging of the pouch cell can be efficiently discharged to the outside of the pouch.

[0031] Through this, the safety of the pouch cell can be improved by delaying or preventing venting of the pouch caused by gas inside the pouch.

[0032] Additionally, the degree to which a portion of the gas discharge member is deformed due to pressure from the gas inside the pouch can be reduced.

[0033] Through this, the performance of discharging gas inside the pouch can be maintained for a relatively long time.

[0034] In addition, the degree to which problems such as whitening and electrolyte seepage occur in the lead film can be reduced.

[0035] The effects according to the present invention are not limited to the contents exemplified above, and more diverse effects are included in this specification.

[0036] FIG. 1 is a perspective view schematically illustrating a pouch cell according to Example 1 of the present invention.

[0037] Fig. 2 is a cross-sectional view schematically illustrating a portion of a cross-section taken along line A-A' of Fig. 1 in a state where a gas passage has been formed.

[0038] FIG. 3 is a plan view schematically illustrating a portion of a pouch cell according to Example 1 of the present invention.

[0039] FIG. 4 is a plan view schematically illustrating a gas discharge member of a pouch cell according to Example 1 of the present invention.

[0040] Figure 5 is a schematic diagram showing the strain of a conventional gas discharge member.

[0041] Figure 6 is a drawing schematically showing the strain of a gas discharge member according to Example 1 of the present invention.

[0042] FIG. 7 is a plan view schematically illustrating a gas discharge member of a pouch cell according to Example 2 of the present invention.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] Example 1

[0047] Figure 1 is a perspective view schematically illustrating a pouch cell (10) according to Example 1 of the present invention.

[0048] A pouch cell (10) according to Example 1 of the present invention may include an electrode assembly (100), a pouch (200), an electrode lead (300), and a lead film (400).

[0049] 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).

[0050] 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.

[0051] 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.

[0052] 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.

[0053] The pouch cell (10) may include an electrode lead (300). The electrode lead (300) 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 (300) protruding outside the pouch (200). Therefore, the electrode lead (300) may be a conductor.

[0054] The lead film (400) can cover the electrode lead (300) so that the pouch (200) and the electrode lead (300) are insulated from each other. Specifically, the lead film (400) can be placed on both sides of the electrode lead (300) to cover the electrode lead (300). The lead films (400) can be configured as a pair and placed on each side of the electrode lead (300).

[0055] 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.

[0056] Specifically, an electrolyte may be accommodated inside the pouch (200) of the pouch cell (10) together with the electrode assembly (100). At this time, residual moisture of the electrolyte inside the pouch (200) of the pouch cell (10) or moisture that has penetrated from the outside may react with the lithium salt 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.

[0057] 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.

[0058] Fig. 2 is a cross-sectional view schematically illustrating a portion of a cross-section taken along line A-A' of Fig. 1 in a state where a gas passage (501) is formed.

[0059] As an example of a configuration capable of discharging gas inside the pouch (200) to the outside of the pouch (200), the pouch cell (10) according to Embodiment 1 of the present invention may further include a gas discharge member (500) to discharge gas inside the pouch (200).

[0060] Referring to FIG. 2, a gas discharge member (500) may be disposed between the electrode lead (300) and the lead film (400). Specifically, the gas discharge member (500) may be provided so that a gas movement path (501) is formed by the gas inside the pouch (200). More specifically, the gas discharge member (500) may be provided so that when the pressure inside the pouch (200) rises above a certain pressure by the gas inside the pouch (200), the gas movement path (501) is formed. At this time, the gas movement path (501) may be formed between the gas discharge member (500) and the lead film (400).

[0061] Specifically, the adhesive force between the gas discharge member (500) and the lead film (400) may be less than the adhesive force between the electrode lead (300) and the gas discharge member (500). Therefore, when the pressure inside the pouch (200) increases due to the gas inside the pouch (200), the adhesive force between the gas discharge member (500) and the lead film (400), which has relatively weak adhesive force, may be degraded. When the adhesive force between the gas discharge member (500) and the lead film (400) is degraded, a space is formed between the gas discharge member (500) and the lead film (400), and this space may become a gas passage (501).

[0062] The gas that has moved through the gas passage (501) can pass through the lead film (400) and be discharged to the outside of the pouch (200). That is, the gas can pass through the lead film (400). Specifically, the lead film (400) can be formed so that only gas can pass through the lead film (400), and liquids and solids cannot move through the lead film (400). At this time, the gas can pass through the lead film (400) by diffusion through movement at the molecular level.

[0063] To form a gas passage (501), the gas discharge member (500) may include a fluorine-based resin. For example, the fluorine-based resin may be PTFE (Polytetrafluoroethylene). In addition, the fluorine-based resin may include PFA, PFEP, ETFE, PVDF, etc.

[0064] Additionally, the gas discharge member (500) may be composed of multiple layers to strengthen adhesion with the electrode lead (300).

[0065] Meanwhile, as the pressure inside the pouch (200) continues to rise, a force may be continuously applied to the gas discharge member (500). Due to this force or pressure, a portion of the gas discharge member (500) may be deformed in shape. In particular, a portion of the gas discharge member (500) may be subject to a concentrated force, resulting in a relatively large deformation rate.

[0066] If the shape of the gas discharge member (500) is deformed, there is a risk that the gas discharge performance of the pouch cell (10) may deteriorate, and problems such as whitening and electrolyte seepage may occur. Therefore, a gas discharge member (500) capable of reducing the deformation rate may be required.

[0067] FIG. 3 is a plan view schematically illustrating a portion of a pouch cell (10) according to Embodiment 1 of the present invention, and FIG. 4 is a plan view schematically illustrating a gas discharge member (500) of a pouch cell (10) according to Embodiment 1 of the present invention.

[0068] As an example of a configuration for reducing strain, the gas discharge member (500) of the pouch cell (10) according to Embodiment 1 of the present invention may have a partially concave shape. Specifically, the gas discharge member (500) may have a shape in which the distance from the reference line (B-B') to the outer end is variable. Here, the reference line (B-B') may be formed between the outer end of the pouch (200) and the outer end of the lead film (400).

[0069] Referring to FIG. 3, the outer end of the gas discharge member (500) may be formed to have a variable distance to the reference line (B-B'). Here, the outer end may refer to a portion that is spaced the farthest from the electrode assembly (100). That is, the outer end of the pouch (200), the outer end of the lead film (400), and the outer end of the gas discharge member (500) may all refer to portions formed in the most upward direction based on FIG. 3 in each configuration. The reference line (B-B') may refer to an imaginary line formed between the outer end of the pouch (200) and the outer end of the lead film (400). In addition, the reference line (B-B') may refer to a line extending in the width direction of the electrode lead (300). Based on FIG. 3, the reference line (B-B') may extend in the horizontal direction.

[0070] When there is a virtual reference line (B-B'), the conventional gas discharge member is formed so that the distance from the outer end to the reference line (B-B') is constant. On the other hand, the outer end of the gas discharge member (500) according to the first embodiment of the present invention may be formed so that the distance to the reference line (B-B') is different. Due to this difference in shape, the gas discharge member (500) according to the first embodiment of the present invention may have relatively little change in shape due to gas pressure.

[0071] Below, the shape of the gas discharge member (500) is described in detail.

[0072] The gas exhaust member (500) may include a first member (510) having a concave shape. Specifically, the gas exhaust member (500) may include a first member (510) and a second member (520).

[0073] The first member (510) of the gas exhaust member (500) may have a partially concave shape with respect to the longitudinal direction of the electrode lead (300). In addition, the second member (520) of the gas exhaust member (500) may extend from the first member (510) toward the electrode assembly (100). Specifically, the first member (510) may have a concave shape formed on the electrode assembly (100) side with respect to the longitudinal direction of the electrode lead (300). In addition, the second member (520) may be formed in multiple pieces. An example in which the second members (520) of the gas exhaust member (500) according to Embodiment 1 of the present invention are formed in a pair will be described.

[0074] Referring to FIG. 4, the first member (510) of the gas discharge member (500) may have a concave shape formed on the electrode assembly (100) side with respect to the longitudinal direction of the electrode lead (300). Here, the longitudinal direction of the electrode lead (300) may mean a vertical direction with reference to FIG. 4. Specifically, the concave shape formed on the electrode assembly (100) side of the first member (510) may be formed between the second members (520). More specifically, the concave shape formed on the electrode assembly (100) side of the first member (510) may be a portion that connects a pair of second members (520) to each other.

[0075] Referring to FIG. 4, the first member (510) of the gas exhaust member (500) may have a concave shape formed on the opposite side of the electrode assembly (100) with respect to the longitudinal direction of the electrode lead (300). Here, the longitudinal direction of the electrode lead (300) may mean a vertical direction with reference to FIG. 4. Specifically, a plurality of concave shapes formed on the opposite side of the electrode assembly (100) in the first member (510) may be formed. An example in which the first member (510) of the gas exhaust member (500) according to Embodiment 1 of the present invention is formed with a pair of concave shapes formed on the opposite side of the electrode assembly (100) is described.

[0076] As an example of a shape for reducing the strain of a gas discharge member (500), the first member (510) of the gas discharge member (500) according to Embodiment 1 of the present invention may have a concave shape including a plurality of line segments that are connected to form obtuse angles with each other. In this case, the size of the obtuse angle formed by the plurality of line segments can be determined through experiments.

[0077] Conventional gas discharge members do not include line segments forming an obtuse angle. Therefore, the pressure caused by the gas inside the pouch (200) may concentrate force in some areas, resulting in high strain. On the other hand, the concave portion of the gas discharge member (500) according to Embodiment 1 of the present invention may be formed of a plurality of line segments that are connected to form an obtuse angle. Therefore, the pressure caused by the gas inside the pouch (200) may be dispersed from being concentrated in some areas, thereby reducing the strain in areas of the gas discharge member (500) where the strain is relatively high.

[0078] Meanwhile, the first member (510) of the gas discharge member (500) may be formed such that the length in the width direction of the electrode lead (300) is less than or equal to the width of the electrode lead (300). If the length of the first member (510) in the width direction of the electrode lead (300) is greater than the width of the electrode lead (300), a portion of the first member (510) may be placed on the outer portion of the electrode lead (300). In this case, there is a high possibility that problems may occur in the sealing of the pouch cell (10) and the insulation of the electrode lead (300). Therefore, the length of the first member (510) in the width direction of the electrode lead (300) may be formed such that the length is less than or equal to the width of the electrode lead (300).

[0079] Referring to FIG. 4, the first member (510) of the gas discharge member (500) according to Embodiment 1 of the present invention may include a first extension portion (511) and a second extension portion (512).

[0080] The first extension portion (511) of the first member (510) may extend in the width direction of the electrode lead (300), and the second extension portion (512) of the first member (510) may extend obliquely with respect to the width direction of the electrode lead (300). In addition, the first extension portion (511) and the second extension portion (512) may be connected to each other. With reference to FIG. 4, the width direction of the electrode lead (300) may mean a horizontal direction. The first member (510) may include a plurality of first extension portions (511) and a plurality of second extension portions (512).

[0081] Referring to FIG. 4, the concave shape of the first member (510) can be formed by a portion where the first extension portion (511) and the second extension portion (512) are connected to each other. Specifically, the concave shape of the first member (510) can be formed by one end of the first extension portion (511) and one end of each of the second extension portions (512) arranged on both sides.

[0082] Meanwhile, the thicknesses of the components included in the gas discharge member (500) may be different from each other.

[0083] The first member (510) of the gas discharge member (500) may have a width narrower than the width of the second member (520). That is, the widths (T1, T2) of all parts of the first member (510) may be narrower than the width (T3) of the second member (520) (see FIG. 4). In addition, the width (T1) of the first extension portion (511) of the first member (510) may be wider than the width (T2) of the second extension portion (512) (see FIG. 4).

[0084] The relative width difference of the configuration included in the gas discharge member (500) may be advantageous for reducing strain through experimentation. In addition, specific values ​​for the width of the configuration capable of minimizing deformation of the gas discharge member (500) can be obtained through repeated experiments.

[0085] The numerical values ​​for the widths of the components included in the gas discharge member (500) obtained through the experiment are approximately as follows. The width (T1) of the first extension portion (511) may be 2 mm or more and 6 mm or less, and the width (T2) of the second extension portion (512) may be 1 mm or more and 5 mm or less. In addition, the width (T3) of the second member (520) may be 3 mm or more and 8 mm or less. Preferably, the width (T1) of the first extension portion (511) may be 3 mm or more and 5 mm or less, the width (T2) of the second extension portion (512) may be 2 mm or more and 4 mm or less, and the width (T3) of the second member (520) may be 5 mm or more and 7 mm or less.

[0086] FIG. 5 is a drawing schematically showing the strain of a conventional gas discharge member (1), and FIG. 6 is a drawing schematically showing the strain of a gas discharge member (500) according to Example 1 of the present invention.

[0087] Figures 5 and 6 are graphs that color-code the degree of deformation of the gas discharge member. Here, the part with a relatively high deformation rate is indicated in red.

[0088] Referring to FIG. 5, it can be seen that the conventional gas discharge member (1) has a relatively high strain at an end positioned on the electrode assembly (100) side and an end positioned on the opposite side of the electrode assembly (100). Here, the end positioned on the electrode assembly (100) side may refer to the lower portion of a portion extending horizontally from the gas discharge member (1), and the end positioned on the opposite side of the electrode assembly (100) may refer to the upper portion of a portion extending horizontally from the gas discharge member (1).

[0089] Referring to FIG. 6, it can be confirmed that the gas discharge member (500) according to Example 1 of the present invention has a relatively reduced portion with a high strain rate compared to the conventional one. In particular, it can be confirmed that the strain rate of the end portion disposed on the electrode assembly (100) side and the end portion disposed on the opposite side of the electrode assembly (100) are relatively reduced.

[0090] The pouch cell (10) according to Embodiment 1 of the present invention may include a gas discharge member (500) having a shape with relatively low deformation. Accordingly, the deformation due to the pressure inside the pouch (200) is reduced, and the gas discharge performance can be maintained for a longer period of time. Through this, the performance of the pouch cell (10) can be maintained for a relatively long period of time. In addition, problems such as whitening of the lead film (400) and electrolyte seepage caused by continuous pressure due to the gas inside the pouch (200) can be prevented or reduced.

[0091] Example 2

[0092] FIG. 7 is a plan view schematically illustrating a gas discharge member (500') of a pouch cell according to Example 2 of the present invention.

[0093] 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.

[0094] The pouch cell according to embodiment 2 of the present invention may have a different shape of the gas discharge member (500') from the pouch cell (10) according to embodiment 1 of the present invention.

[0095] A gas discharge member (500') according to Embodiment 2 of the present invention may include a first member (510') and a second member (520'). Specifically, the first member (510') may have a partially concave shape with respect to the longitudinal direction of the electrode lead (300), and the second member (520') may extend from the first member (510') toward the electrode assembly (100). More specifically, the first member (510') may have a concave shape formed on the side of the electrode assembly (100) and a concave shape formed on the opposite side of the electrode assembly (100) with respect to the longitudinal direction of the electrode lead (300).

[0096] Referring to FIG. 7, the gas discharge member (500') according to the second embodiment of the present invention may include a first member (510') having a concave shape including a curve. That is, in the first member (510'), with respect to the longitudinal direction of the electrode lead (300), the concave shape formed on the side of the electrode assembly (100) and the concave shape formed on the opposite side of the electrode assembly (100) may include a curve.

[0097] Since the first member (510') of the gas discharge member (500') according to Example 2 of the present invention includes a concave shape including a curve, the degree to which the shape is deformed by the gas inside the pouch (200) can be relatively reduced compared to the conventional gas discharge member (1).

[0098] Meanwhile, the first member (510') may be formed in a round shape at the part where the first extension and the second extension are connected.

[0099] Although not described in detail in the present invention, the concave shape formed in the first member of the gas discharge member may include both curves and line segments.

[0100] 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 an anode, a cathode, and a separator; A pouch accommodating the above electrode assembly; An electrode lead electrically connected to the electrode assembly and protruding outside the pouch; A lead film covering a portion of the electrode lead so that the electrode lead is insulated from the pouch; and A gas discharge member is disposed between the electrode lead and the lead film and is provided so that a gas movement path is formed by the gas inside the pouch. The above gas discharge absence is, A first member having a concave shape in part with respect to the length direction of the electrode lead; and A pouch cell comprising a second member extending from the first member toward the electrode assembly.

2. In paragraph 1, The above first absence is, A pouch cell having a concave shape formed on the electrode assembly side with respect to the longitudinal direction of the electrode lead.

3. In paragraph 1, The above first absence is, A pouch cell having a concave shape formed on the opposite side of the electrode assembly with respect to the longitudinal direction of the electrode lead.

4. In paragraph 1, The above first absence is, A pouch cell having a concave shape including a curve.

5. In paragraph 1, The above first absence is, A pouch cell having a concave shape including a plurality of line segments that are connected to form obtuse angles with each other.

6. In paragraph 1, The above first absence is, A pouch cell having a width narrower than the width of the second member.

7. In paragraph 1, The above first absence is, a first extension portion extending in the width direction of the electrode lead; and A pouch cell comprising a second extension portion connected to the first extension portion and extending obliquely with respect to the width direction of the electrode lead.

8. In paragraph 7, The above first extension part, A pouch cell having a width wider than the width of the second extension.

9. In paragraph 1, The above first absence is, A pouch cell, wherein the length of the electrode lead in the width direction is formed to be less than or equal to the width of the electrode lead.

10. In paragraph 1, The above gas discharge absence is, A pouch cell in which the adhesive strength with the lead film is smaller than the adhesive strength with the electrode lead.

11. In paragraph 1, The above gas discharge absence is, A pouch cell containing PTFE.

12. An electrode assembly comprising an anode, a cathode, and a separator; A pouch accommodating the above electrode assembly; An electrode lead electrically connected to the electrode assembly and protruding outside the pouch; A lead film covering a portion of the electrode lead so that the electrode lead is insulated from the pouch; and A gas discharge member is disposed between the electrode lead and the lead film and is provided so that a gas movement path is formed by the gas inside the pouch. The above gas discharge absence is, A pouch cell, wherein the distance from a reference line extending in the width direction of the electrode lead to the outer end between the outer end of the pouch and the outer end of the lead film is variable.

13. A first member having a concave shape; and A gas exhaust member comprising a second member connected to the first member and extending in a direction away from the first member.

14. In paragraph 13, The above first absence is, A gas discharge member having a concave shape formed on both sides with respect to the direction of extension and the direction perpendicular to the direction of extension.

15. In paragraph 13, The above first absence is, A gas discharge member having a concave shape including a plurality of line segments that are connected to form obtuse angles with each other.

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