Pouch Cell

Abstract

The present invention relates to a pouch cell that can release gas inside the pouch to the outside of the pouch so as to delay or prevent the occurrence of pouch venting caused by internal gas generated during charging or discharging of the pouch cell. A pouch cell according to the present invention includes an electrode assembly, a pouch accommodating the electrode assembly, an electrode lead electrically connected to the electrode assembly and protruding outside the pouch, a pair of lead films including a center portion covering a portion of the electrode lead on both sides of the electrode lead so as to insulate the pouch from the electrode lead, and outer portions disposed on both sides of the center portion, and a passage member disposed between the pair of lead films and attached to the outer portions, and when the pressure inside the pouch rises above a set pressure, a gas transfer path may be formed between the passage member and the lead film.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0171496 filed on December 9, 2022 and Korean Patent Application No. 10-2023-0045409 filed on April 6, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a pouch cell, and more particularly to a secondary battery pouch cell that can be charged and discharged. [Background technology]

[0003] In recent years, with rising energy prices due to the depletion of fossil fuels and growing concerns about environmental pollution, the demand for environmentally friendly alternative energy sources has become an essential factor for future life. Accordingly, research into various power generation technologies, such as solar, wind, and tidal power, has been ongoing, and there has also been great interest in power storage devices, such as batteries, to more efficiently use the electrical energy produced in this way.

[0004] Furthermore, with the increasing technological development and demand for battery-based electronic mobile devices and electric vehicles, the demand for batteries as an energy source is rapidly increasing, and a great deal of research is being conducted into batteries that can meet the resulting diverse demands.

[0005] Batteries that store electrical energy are generally classified as primary batteries and secondary batteries. While primary batteries are disposable, secondary batteries are rechargeable batteries manufactured using materials that allow repeated oxidation and reduction processes between electric current and materials. That is, when a reduction reaction occurs in a material due to electric current, the power source is charged, and when an oxidation reaction occurs in the material, the power source is discharged. Electricity is generated as this charge-discharge cycle is repeated.

[0006] Secondary batteries can be classified into cylindrical cells, pouch cells, prismatic cells, etc., depending 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 stacked inside a pouch and sealing the outside of the pouch.

[0007] Meanwhile, the pouch of a pouch cell may contain an electrolyte solution along with an electrode assembly. Residual moisture in the electrolyte solution or moisture permeating from the outside may react with the lithium salt inside the pouch to generate HF (hydrogen fluoride), and decomposition of the electrolyte may generate gases such as carbon dioxide, carbon monoxide, ethylene, and methane. Furthermore, depending on the positive electrode material contained in the electrode assembly of the pouch cell, additional hydrogen and HF may be generated, which may lead to overheating due to overcharging or internal short circuits during charging and discharging. This may result in the generation of a large amount of gas inside the pouch. This gas may increase the pressure inside the pouch, which may cause the pouch to expand (swelling) or partially rupture (venting).

[0008] In conventional pouch cells, the pressure increases due to the internal gas, and the increased pressure damages the sealing of the sealed part. In addition, the deterioration of the sealing of the sealed part causes the problem of venting, where the pouch opens due to pressure.

[0009] A pouch cell in which venting occurs cannot function as a secondary battery, and therefore, in order to prevent or delay the occurrence of venting, a pouch cell is currently required that includes a configuration that allows gas inside the pouch to be released to the outside of the pouch. Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a pouch cell that can release gas inside the pouch to the outside of the pouch so as to delay or prevent the occurrence of a pouch venting phenomenon caused by internal gas generated during charging or discharging of the pouch cell. [Means for solving the problem]

[0011] A pouch cell according to the present invention includes an electrode assembly, a pouch accommodating the electrode assembly, an electrode lead electrically connected to the electrode assembly and protruding outside the pouch, a pair of lead films including a center portion covering a portion of the electrode lead on both sides of the electrode lead so as to insulate the pouch from the electrode lead, and outer portions disposed on both sides of the center portion, and a passage member disposed between the pair of lead films and attached to the outer portions, and when the pressure inside the pouch rises above a set pressure, a gas transfer path may be formed between the passage member and the lead film.

[0012] The pouch can cover a portion of the lead film and a portion of the passage member.

[0013] One end of the lead film in the width direction may be spaced apart from the pouch, and the passage member may be disposed so as to be spaced apart from the one end.

[0014] The passage member may be positioned to be spaced apart from the electrode lead.

[0015] The passage member may be disposed so as to be spaced apart from both ends of the lead film in the longitudinal direction.

[0016] The cross-sectional area of ​​the portion where the outer portion overlaps with the passage member may be 10% or more and 90% or less of the cross-sectional area of ​​the outer portion.

[0017] At least one of the pair of lead films may have a surface facing the passage member, the portion overlapping the passage member coated with a fluorine-based resin.

[0018] At least one of the pair of lead films may have, on one surface facing the passage member, a surface roughness of a portion overlapping the passage member that is greater than a surface roughness of a portion not in contact with the passage member.

[0019] The portion that overlaps with the passage member may be plasma treated or primer treated so that the surface roughness is greater than the surface roughness of the portion that does not contact the passage member.

[0020] At least one of the pair of lead films may have a surface roughness (R) of 20 nm or more and 140 nm or less at a portion overlapping with the passage member on one surface facing the passage member.

[0021] At least one of the pair of lead films may have a surface coated with a fluorine-based resin, the surface having a surface roughness (R) of 20 nm or more and 140 nm or less.

[0022] The passage member may contain a fluorine-based resin.

[0023] The fluorine-based resin may be PTFE (Polytetrafluoroethylene). [Effects of the Invention]

[0024] A pouch cell according to the present invention includes an electrode assembly, a pouch accommodating the electrode assembly, an electrode lead electrically connected to the electrode assembly and protruding outside the pouch, a pair of lead films including a center portion covering a portion of the electrode lead on both sides of the electrode lead so as to insulate the pouch from the electrode lead, and outer portions disposed on both sides of the center portion, and a passage member disposed between the pair of lead films and attached to the outer portions, and when the pressure inside the pouch rises above a set pressure, a gas transfer path may be formed between the passage member and the lead film.

[0025] Therefore, gas generated inside the pouch during charging or discharging of the pouch cell can be discharged to the outside.

[0026] This can delay or prevent the venting phenomenon of the pouch caused by gas inside the pouch, thereby improving the safety of the pouch cell.

[0027] Furthermore, it is possible to prevent the adhesive strength between the lead film and the electrode lead from weakening.

[0028] Furthermore, the safety of the pouch cell can be improved by preventing moisture from permeating into the electrode lead through the lead film.

[0029] The effects of the present invention are not limited to the above-mentioned examples, and various other effects may be included within the present specification. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a perspective view schematically illustrating a pouch cell according to a first embodiment of the present invention. [Figure 2] 1 is a plan view schematically showing a state in which a part of a pouch cell according to Example 1 of the present invention is seen from above. [Figure 3] 3 is a cross-sectional view schematically illustrating a cross section of a pouch cell according to a first embodiment of the present invention taken along line AA' of FIG. 2. FIG. [Figure 4] 3 is a cross-sectional view schematically illustrating a cross section of a pouch cell according to a first embodiment of the present invention, in which a gas transfer path is formed, taken along the line AA' of FIG. 2.

[0023] FIG. [Figure 5] 3 is a cross-sectional view schematically illustrating a cross section of a pouch cell according to a second embodiment of the present invention taken along the line AA' of FIG. 2. FIG. [Figure 6] 3 is a cross-sectional view schematically illustrating a cross section of a pouch cell according to a second embodiment of the present invention, in which a gas transfer path is formed, taken along the line AA' of FIG. 2. FIG. [Figure 7]3 is a cross-sectional view schematically illustrating a cross section of a pouch cell according to a third embodiment of the present invention taken along the line AA' of FIG. 2. FIG. [Figure 8] 3 is a cross-sectional view schematically illustrating a cross section of a pouch cell according to a fourth embodiment of the present invention taken along the line AA' of FIG. 2. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily understand the present invention. However, the present invention may be embodied in various different forms and is not limited to the following embodiments.

[0032] In order to clearly explain the present invention, detailed descriptions of parts that are not relevant to the explanation or related known technologies that may obscure the gist of the present invention will be omitted, and in this specification, when adding reference numbers to components in each drawing, the same or similar reference numbers will be used throughout the specification for the same or similar components.

[0033] Furthermore, the terms and words used in this specification and claims should not be interpreted in a way that is limited to their ordinary and dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, in accordance with the principle that the inventor himself / herself can appropriately define the concept of a term in order to explain the invention in the best possible way.

[0034] FIG. 1 is a perspective view schematically showing a pouch cell 10 according to a first embodiment of the present invention.

[0035] The pouch cell 10 according to the first embodiment of the present invention may include an electrode assembly 500, a pouch 400, an electrode lead 100, a lead film 200, and a passage member 300.

[0036] The pouch cell 10 described in the present invention may refer to a secondary battery capable of being charged and discharged. Specifically, it may refer to a secondary battery having a shape in which an electrode assembly 500 including a negative electrode, a positive electrode, and a separator is disposed inside a pouch 400, and the pouch 400 encases the electrode assembly 500. Specifically, the pouch cell 10 may refer to a secondary battery in which the electrode assembly 500 including a negative electrode, a positive electrode, and a separator is housed inside the pouch 400 together with an electrolyte.

[0037] The electrode assembly 500 may have a stacked shape or a rolled-up jelly-roll shape in which the negative electrode, the positive electrode, and the separator are stacked, and the pouch 400 may house the electrode assembly 500. Specifically, the pouch 400 may include a cup-shaped portion that can house the electrode assembly 500 and the electrolyte solution therein.

[0038] The electrode lead 100 may be electrically connected to the electrode assembly 500 and disposed in a shape that protrudes outside the pouch 400. The electrode lead 100 protruding outside the pouch 400 allows the pouch cell 10 to provide electrical energy to the outside. Therefore, the electrode lead 100 may serve as a conductor.

[0039] The lead film 200 may cover the electrode lead 100 so that the pouch 400 and the electrode lead 100 are insulated from each other. Specifically, the lead film 200 may be disposed on both sides of the electrode lead 100 to cover the electrode lead 100. The lead films 200 may be configured as a pair and may be disposed on both sides of the electrode lead 100, respectively.

[0040] Meanwhile, the lead film 200 may include an insulating material to insulate the pouch 400 from the electrode lead 100. The electrode lead 100 may have a substantially rectangular parallelepiped shape, but is not necessarily limited thereto.

[0041] The lead film 200 according to the first embodiment of the present invention may include a central portion 210 and an outer portion 220. Specifically, the central portion 210 of the lead film 200 may be disposed at a position corresponding to the position of the electrode lead 100 to cover the electrode lead 100, and the outer portions 220 may be disposed on both sides of the central portion 210. Therefore, the central portion 210 may be in contact with the electrode lead 100, and the outer portions 220 may not be in contact with the electrode lead 100.

[0042] FIG. 2 is a plan view schematically showing a part of the pouch cell 10 according to the first embodiment of the present invention as viewed from above.

[0043] As the pouch cell 10 is repeatedly charged and discharged, gas may be generated, which may increase the pressure inside the pouch 400. If the pressure inside the pouch 400 increases too much, a venting phenomenon may occur, which may cause the pouch cell 10 to lose its function. As an example of a configuration for preventing an increase in pressure inside the pouch 400, the pouch cell 10 according to the first embodiment of the present invention may include a passage member 300.

[0044] 2, the passage member 300 may be disposed between a pair of lead films 200. That is, the lead films 200 may be disposed on both sides of the passage member 300. Regarding a specific position, the passage member 300 may be disposed on an outer portion 220 of the lead film 200. In this case, the passage member 300 may be disposed on one of the pair of outer portions 220, or on each of the pair of outer portions 220.

[0045] Since the passage member 300 is disposed on the outer portion 220 of the lead film 200, the passage member 300 does not interfere with the adhesion between the lead film 200 and the electrode lead 100. Therefore, even if the passage member 300 is disposed in the pouch cell 10, there is no risk of the adhesive strength between the lead film 200 and the electrode lead 100 being weakened.

[0046] The adhesive strength between the passage member 300 and the lead film 200 may be weaker than the adhesive strength between the passage member 300 and the lead film 200. In this regard, in order to weaken the adhesive strength with the lead film 200, the passage member 300 may include a fluorine-based resin. For example, the fluorine-based resin may be PTFE (Polytetrafluoroethylene). Other examples of the fluorine-based resin include PFA, PFEP, ETFE, PVDF, etc.

[0047] Because the adhesive strength at the portion where the passage member 300 is disposed is weaker than when the lead films 200 are bonded together, the bond between the passage member 300 and the lead film 200 may break even at a relatively low pressure. Therefore, when the pressure inside the pouch 400 rises above a certain pressure, a space may be formed between the passage member 300 and the lead film 200. That is, when the pressure inside the pouch 400 rises above a set pressure, a gas transfer path 230 may be formed between the passage member 300 and the lead film 200. Gas inside the pouch 400 can transfer through the gas transfer path 230 formed between the passage member 300 and the lead film 200, and the transferred gas can pass through the lead film 200 and be discharged to the outside of the pouch 400. At this time, the gas can pass through the lead film 200 by diffusion.

[0048] The pouch cell 10 according to the first embodiment of the present invention includes the passage member 300, which allows the gas inside the pouch 400 to be efficiently discharged to the outside. This also delays or prevents the occurrence of venting, thereby improving the stability of the pouch cell 10.

[0049] The shape of the passage member 300 may vary. Preferably, the passage member 300 may have a substantially rectangular cross section so that a constant gas transfer path 230 can be formed in the longitudinal direction of the passage member 300. Gas can move stably through the gas transfer path 230 of a constant width.

[0050] Meanwhile, the pouch 400 may be sealed to close a portion of the pouch 400 that was opened during the manufacturing process of the pouch cell 10. In this case, the pouch 400 may be sealed by heat and pressure after a portion of the electrode lead 100, a portion of the lead film 200, and a portion of the pass-through member 300 are disposed inside the pouch 400. Therefore, the pouch 400 can cover a portion of the electrode lead 100, a portion of the lead film 200, and a portion of the pass-through member 300.

[0051] The shape in which the passage member 300 is arranged will be described in more detail below.

[0052] 2, one end 221 of the lead film 200 may be spaced apart from the pouch 400 in the width direction, and the other end 222 may be covered by the pouch 400. With reference to FIG. 2, the width direction of the lead film 200 may refer to the up-down direction. In this case, the passageway member 300 may be disposed to form a distance t1 with one end 221 of the lead film 200, which is disposed to be spaced apart from the pouch 400. Specifically, one end 301 of the passageway member 300 that is not covered by the pouch 400 may have a specific distance t1 with one end 221 of the outer portion 220 of the lead film 200, which is disposed relatively far from the pouch 400.

[0053] Meanwhile, the passageway member 300 may be arranged in line with the other end 222 of the lead film 200 that is covered by the pouch 400. Specifically, the other end 302 of the passageway member 300 that is covered by the pouch 400 may be arranged in line with the other end 222 of the outer portion 220 of the lead film 200.

[0054] When one end 301 of the passage member 300 is positioned on the same line as one end 221 of the lead film 200, if the internal pressure of the pouch 400 exceeds a set pressure, there is a possibility that the gap between the passage member 300 and the lead film 200 will open to the outside. Therefore, in this case, gas cannot be discharged by permeation through the lead film 200, and even the electrolyte may leak out of the pouch 400. By arranging one end 301 of the passage member 300 so as to form a gap t1 with one end 221 of the lead film 200, the above-mentioned problem can be prevented.

[0055] Furthermore, if the other end 302 of the passage member 300 is not positioned on the same line as the other end 222 of the lead film 200, it may be difficult to connect the open portion between the passage member 300 and the lead film 200 with the inside of the pouch 400. This is because there is a portion where the lead films 200 are bonded to each other between the open portion and the inside of the pouch 400, and therefore even if the internal pressure of the pouch 400 exceeds the set pressure, there is a possibility that the gap between the open portion and the inside of the pouch 400 will be clogged. By positioning the other end 302 of the passage member 300 on the same line as the other end 222 of the lead film 200, the above-mentioned problems can be prevented.

[0056] In summary, in order to facilitate gas discharge by permeation, one end 301 of the passage member 300 may be spaced apart from one end 221 of the lead film 200 , while the other end 302 may be positioned in line with the other end 222 of the lead film 200 .

[0057] 2, the passage member 300 according to the first embodiment of the present invention may be disposed so as to be spaced apart from the electrode lead 100. Specifically, a predetermined distance t2 may be formed between the electrode lead 100 and the passage member 300. That is, the passage member 300 may be disposed so as to be spaced apart from the center portion 210 of the lead film 200.

[0058] Since the pass-through member 300 is disposed at a distance from the electrode lead 100 , the adhesion between the electrode lead 100 and the lead film 200 may not be hindered by the pass-through member 300 .

[0059] Meanwhile, the passage member 300 according to the first embodiment of the present invention may be disposed to form a distance t3 with both ends of the lead film 200 in the longitudinal direction. Here, the longitudinal direction of the lead film 200 may refer to the horizontal direction with reference to FIG. 2.

[0060] The reason for arranging the passage member 300 in this manner may be the same as the reason for arranging one end of the lead film 200 in the width direction to form a distance t1 with the passage member 300 described above. In other words, if the passage member 300 is not arranged to form a distance t3 with both ends of the lead film 200 in the length direction, gas cannot be discharged by permeation through the lead film 200, and even the electrolyte may leak out of the pouch 400.

[0061] From the above-described arrangement of the passage member 300, it can be expected that the cross-sectional area of ​​the passage member 300 is smaller than the cross-sectional area of ​​the outer portion 220. In this regard, when the cross-sectional area occupied by the passage member 300 is explained in terms of a percentage, the cross-sectional area of ​​the passage member 300 may be 10% or more and 90% or less of the cross-sectional area of ​​the outer portion 220.

[0062] If the cross-sectional area of ​​the passage member 300 is less than 10% of the cross-sectional area of ​​the outer portion 220, there may not be enough space for the gas transfer path 230 to be formed, which may significantly weaken the gas discharge performance of the pouch cell 10.

[0063] Furthermore, if the cross-sectional area of ​​the passage member 300 exceeds 90% of the cross-sectional area of ​​the outer portions 220, the sealing strength of the facing outer portions 220 may be reduced. In this case, the weakened sealing strength may weaken the hermeticity of the lead film 200.

[0064] Preferably, the cross-sectional area of ​​the passage member 300 may be 30% to 70% of the cross-sectional area of ​​the outer portion 220. This value may be determined by taking into consideration both the gas discharge performance and the sealing performance of the pouch cell 10.

[0065] FIG. 3 is a cross-sectional view schematically showing a cross section of a pouch cell 10 according to Example 1 of the present invention taken along A-A' in FIG. 2, and FIG. 4 is a cross-sectional view schematically showing a cross section of a pouch cell 10 according to Example 1 of the present invention, in which a gas transfer path 230 is formed, taken along A-A' in FIG. 2.

[0066] The lead film 200 may have a three-layer structure. The lead film 200 may include a pouch adhesive layer 2001 disposed on a portion that contacts the pouch 400 for adhesion to the pouch 400. The lead film 200 may also include a metal adhesive layer 2003 disposed on the opposite side of the lead film 200 or on a portion that contacts the electrode lead 100. At the same time, the lead film 200 may include a core layer 2002 disposed between the pouch adhesive layer 2001 and the metal adhesive layer 2003. This is merely one example, and the lead film 200 may have other configurations.

[0067] As an example of a configuration for preventing moisture and the like from penetrating into the pouch 400, a portion of one side of the lead film 200 may be processed to have increased surface roughness. That is, a portion of the metal adhesive layer 2003 in the lead film 200 having a three-layer structure that comes into contact with the passageway member 300 may be surface roughened. Specifically, at least one of the pair of lead films 200 may be processed to have increased surface roughness on one side of the metal adhesive layer 2003 that faces the passageway member 300. More specifically, at least one of the pair of lead films 200 may have a surface roughness of a portion of its one side facing the passageway member 300 that overlaps with the passageway member 300 that is greater than the surface roughness of a portion that does not come into contact with the passageway member 300. Hereinafter, the portion that has been surface roughened to have increased surface roughness will be referred to as a roughness-processed portion 201.

[0068] Meanwhile, as an example of a method for processing to increase the surface roughness, the portion of the side of the lead film 200 facing the passage member 300 that overlaps with the passage member 300 may be plasma-treated or primer-treated. In this case, the plasma treatment may mean that plasma comes into contact with an object and energy acts on the surface, thereby deforming the shape of the surface. Furthermore, the primer treatment may mean that an object is treated with a primer. The plasma treatment or primer treatment is merely an example of a processing method, and the surface may be processed by other methods. In particular, other processing methods that can form nanometer-level roughness may be used.

[0069] When the pressure inside the pouch 400 rises above a set pressure, the pouch cell 10 may change from the state shown in Fig. 3 to the state shown in Fig. 4. Referring to Fig. 4, when the pressure inside the pouch 400 rises above a set pressure, a space may be formed between the lead film 200 and the passage member 300 of the pouch cell 10. This space may become a gas transfer path 230 through which gas can transfer.

[0070] When a gas transfer path 230 is formed between the lead film 200 and the passage member 300, moisture may penetrate into the pouch 400 through the lead film 200. In this case, a surface with a relatively large surface roughness has increased hydrophobicity, which can prevent moisture from penetrating into the pouch 400 through the lead film 200. Therefore, it is possible to prevent a deterioration in the function of the pouch cell 10 or corrosion of the electrode lead 100 due to moisture penetrating into the pouch 400.

[0071] Meanwhile, as an example of the degree of increase in surface roughness, at least one of the pair of lead films 200 according to the first embodiment of the present invention may have a surface roughness (R) of 20 nm to 140 nm at a portion of one side facing the passage member 300 that overlaps with the passage member 300. This surface roughness value may be a value that facilitates gas discharge and improves hydrophobicity, and may be a value obtained through experiments. Also, this surface roughness value may be the easiest value for achieving the effects of the present invention.

[0072] The pouch cell 10 according to the first embodiment of the present invention can reduce the risk of venting by discharging gas generated inside the pouch 400 to the outside when the pressure inside the pouch 400 increases. At the same time, the pouch cell 10 according to the first embodiment of the present invention can improve safety by preventing moisture from penetrating into the pouch 400 through the gas transfer path.

[0073] Hereinafter, detailed description of the same configuration as the pouch cell 10 according to the first embodiment of the present invention will be omitted.

[0074] FIG. 5 is a cross-sectional view schematically showing a cross section of a pouch cell 10 according to a second embodiment of the present invention taken along A-A' in FIG. 2, and FIG. 6 is a cross-sectional view schematically showing a cross section of a pouch cell 10 according to a second embodiment of the present invention, in which a gas transfer path 230 is formed, taken along A-A' in FIG. 2.

[0075] As an example of a configuration for preventing moisture and the like from penetrating into the pouch 400, the lead film 200 of the pouch cell 10 according to the second embodiment of the present invention may be coated with a fluororesin. Specifically, at least one of the pair of lead films 200 may have one side facing the passageway member 300, the portion overlapping with the passageway member 300, coated with a fluororesin. More specifically, one side of the metal adhesive layer 2003 at the outer portion 220 of the lead film 200 facing the passageway member 300 may be coated with a fluororesin. Hereinafter, the portion coated with the fluororesin will be referred to as a fluororesin-coated portion 202.

[0076] When the pressure inside the pouch 400 rises above a set pressure, the pouch cell 10 may change from the state shown in Fig. 5 to the state shown in Fig. 6. Referring to Fig. 6, when the pressure inside the pouch 400 rises above a set pressure, a space may be formed between the lead film 200 and the passage member 300 of the pouch cell 10. This space may become a gas transfer path 230 through which gas can transfer.

[0077] When a gas transfer path 230 is formed between the lead film 200 and the passage member 300, moisture may penetrate into the pouch 400 through the gas lead film 200. In this case, the surface coated with the fluorine-based resin has increased hydrophobicity, which can prevent moisture from penetrating into the pouch 400 through the lead film 200. Therefore, it is possible to prevent a deterioration in the function of the pouch cell 10 or corrosion of the electrode lead 100 due to moisture penetrating into the pouch 400.

[0078] FIG. 7 is a cross-sectional view schematically showing a cross section of a pouch cell 10 according to a third embodiment of the present invention taken along line AA' of FIG.

[0079] As an example of a configuration for more efficiently preventing moisture and the like from penetrating into the pouch 400, the lead film 200 of the pouch cell 10 according to Example 3 of the present invention may be processed to have a large surface roughness and then coated with a fluorine-based resin. Specifically, at least one of the pair of lead films 200 may be processed on one side facing the passage member 300 to have a large surface roughness at a portion overlapping with the passage member 300 and then coated with a fluorine-based resin. More specifically, one side of the metal adhesive layer 2003 at a portion facing the passage member 300 in the outer portion 220 of the lead film 200 may be processed to have a large surface roughness and then coated with a fluorine-based resin.

[0080] 7, the lead film 200 at a portion facing the passage member 300 may have a fluororesin coating portion 202 formed on a roughness-treated portion 201. That is, the lead film 200 may be manufactured through a manufacturing process in which a portion of one side is roughened and then coated with a fluororesin.

[0081] When one side of the lead film 200 is subjected to both the surface roughening treatment and the fluorine-based resin treatment, it becomes more hydrophobic, so that the penetration of moisture into the pouch 400 can be more efficiently reduced.

[0082] Meanwhile, the lead film 200 may be manufactured through a manufacturing process in which a portion of one side is coated with a fluorine-based resin and then the portion is roughened. That is, the positions of the roughness-treated portion 201 and the fluorine-based resin-coated portion 202 may be variable.

[0083] FIG. 8 is a cross-sectional view schematically showing a cross section of the pouch cell 10 according to the fourth embodiment of the present invention taken along line AA' of FIG.

[0084] 8, one of the pair of lead films 200 may be coated with a fluorine-based resin after being processed on one side facing the passage member 300 so that the surface roughness of the portion overlapping with the passage member 300 is increased. Also, the other of the pair of lead films 200 may be coated with a fluorine-based resin on one side facing the passage member 300 so that the surface roughness of the portion overlapping with the passage member 300 is increased.

[0085] Meanwhile, the roughness-treated portion 201 and the fluororesin coating portion 202 may be disposed at the same or different positions on both sides of the passage member 300. Figure 8 illustrates a case where the roughness-treated portion 201 and the fluororesin coating portion 202 are disposed at different positions on both sides of the passage member 300.

[0086] The pouch cell 10 according to the fourth embodiment of the present invention can increase the hydrophobicity on both sides of the passageway member 300. Therefore, when the pressure inside the pouch 400 is equal to or higher than a set pressure, it is possible to more efficiently prevent moisture and the like from permeating through the gas transfer paths 230 formed on both sides of the passageway member 300.

[0087] Although the present invention has been described above using limited examples and drawings, the present invention is not limited thereto, and various implementations are possible within the technical spirit of the present invention and the scope of the claims set forth below by a person having ordinary skill in the art to which the present invention pertains. [Explanation of symbols]

[0088] 10 pouch cells 100 electrode leads 200 lead film 201 Roughness processing section 202 Fluorine resin coating part 210 Center 220 Outer part 230 Gas Transfer Path 300 Passageway components 400 pouches 500 electrode assembly

Claims

1. an electrode assembly; a pouch that accommodates the electrode assembly; an electrode lead electrically connected to the electrode assembly and protruding outside the pouch; a pair of lead films including a central portion covering a part of the electrode lead on both sides of the electrode lead so as to insulate the pouch from the electrode lead, and outer portions disposed on both sides of the central portion; a passage member disposed between the pair of lead films and attached to the outer portion; A pouch cell comprising: When the pressure inside the pouch rises above a set pressure, a gas transfer path is formed between the passage member and the lead film.

2. The pouch comprises: The pouch cell according to claim 1 , wherein the pouch cell covers a portion of the lead film and a portion of the passage member.

3. one end of the lead film in the width direction is spaced apart from the pouch; The passage member is The pouch cell according to claim 1 or 2, which is disposed so as to be spaced apart from the one end.

4. The passage member is The pouch cell according to claim 1 , wherein the pouch cell is disposed so as to be spaced apart from the electrode lead.

5. The passage member is The pouch cell according to claim 1 , wherein the lead film is disposed so as to be spaced apart from both longitudinal ends of the lead film.

6. The pouch cell according to claim 1 , wherein a cross-sectional area of ​​the portion where the outer portion overlaps with the passage member is 10% to 90% of a cross-sectional area of ​​the outer portion.

7. At least one of the pair of lead films is The pouch cell according to claim 1 , wherein a portion of the surface facing the passage member that overlaps with the passage member is coated with a fluorine-based resin.

8. At least one of the pair of lead films is The pouch cell according to claim 1 , wherein, on one surface facing the passage member, a surface roughness of a portion overlapping the passage member is greater than a surface roughness of a portion not in contact with the passage member.

9. The portion overlapping with the passage member is The pouch cell of claim 8 , wherein the surface roughness is greater than the surface roughness of the portion not in contact with the passage member.

10. At least one of the pair of lead films is 2. The pouch cell according to claim 1, wherein a surface roughness (R) of a portion of the one surface facing the passage member that overlaps with the passage member is 20 nm or more and 140 nm or less.

11. At least one of the pair of lead films is 10. The pouch cell according to claim 9, wherein the surface having a surface roughness (R) of 20 nm or more and 140 nm or less is coated with a fluorine-based resin.

12. The passage member is The pouch cell according to claim 1 , comprising a fluorine-based resin.

13. The fluorine-based resin is 13. The pouch cell of claim 12, which is PTFE.

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