Soft package battery monomer

Abstract

The present invention relates to a pouch battery cell capable of improving sealing durability of a joint portion to delay or prevent exhaust caused by gas generated during charging and discharging of the pouch battery cell. The pouch battery cell according to the present invention comprises: an electrode assembly; an inner soft wrapping film covering a part of the electrode assembly; and an outer soft wrapping film which surrounds the outer periphery of the inner soft wrapping film and is combined with the inner soft wrapping film so as to cover the outer surface of the electrode assembly together with the inner soft wrapping film.

Description

Technical Field

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10 - 2022 - 0171497, filed on December 9, 2022, Korean Patent Application No. 10 - 2023 - 0044304, filed on April 4, 2023, and Korean Patent Application No. 10 - 2023 - 0174817, filed on December 5, 2023, the entire disclosures of which are incorporated herein by reference. Technical Field

[0004] The present invention relates to a pouch - type battery cell, and more particularly, to a secondary battery pouch - type battery cell capable of charging and discharging. Background Art

[0005] Recently, due to the depletion of fossil fuels and the growing concern about environmental pollution, rising energy prices have driven the demand for environmentally friendly alternative energy sources as a top priority for future life. Therefore, research on technologies for generating various energies such as photovoltaic energy, wind energy, and tidal energy is ongoing, and energy storage devices (such as batteries) for more effectively using the generated electric energy have also attracted a lot of attention.

[0006] In addition, with technological development and the increasing demand for electric mobile devices and electric vehicles using batteries, the demand for batteries as an energy source has increased significantly, and accordingly, research on batteries capable of meeting various requirements has been conducted.

[0007] Batteries for storing energy are generally classified into primary batteries and secondary batteries. A primary battery is a disposable consumable battery, but on the other hand, a secondary battery is a rechargeable battery manufactured using materials that can repeatedly perform the oxidation and reduction processes between current and substances. That is, it is charged when a reduction reaction is performed on the material by current, and discharged when an oxidation reaction is performed on the material. Therefore, such charging and discharging are repeated to generate electric energy.

[0008] Secondary batteries can be classified into cylindrical battery cells, pouch - type battery cells, and prismatic battery cells according to their shapes. In particular, a pouch - type battery cell can be manufactured in such a form that an electrode assembly in which a positive electrode, a negative electrode, a separator, etc. are laminated is accommodated inside a pouch, and the outside of the pouch is sealed.

[0009] Meanwhile, the electrolyte and the electrode assembly can be accommodated inside the pouch of the pouch cell. In this case, residual moisture in the electrolyte inside the pouch of the pouch cell or moisture infiltrated from the outside may react with the lithium salt to generate hydrogen fluoride (HF), and decomposition of the electrolyte may generate gases such as carbon dioxide, carbon monoxide, ethylene, and methane. Additionally, 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 cause overheating due to overcharging and internal short circuits during the charge and discharge process. Therefore, a large amount of gas may be generated inside the pouch. Due to this gas, the pressure inside the pouch increases, and the increased pressure may cause the pouch to expand or exhaust through rupture of a part of the pouch.

[0010] Figure 1 is a cross-sectional view schematically showing a cross-section of a conventional pouch cell.

[0011] Referring to Figure 1 , a conventional pouch cell can be formed such that a pair of pouch films are formed to be joined by facing each other. Specifically, an electrode assembly including a positive electrode, a negative electrode, and a separator is disposed on the cup portions of a pair of pouch films facing each other, and electrode leads electrically connected to the electrode assembly can be formed to protrude to the outside of the pouch film.

[0012] In addition, in a conventional pouch cell, each of the pair of pouch films has a sealant layer on the side facing each other. Therefore, when the sealant layers facing each other are heated and melted, the pair of pouch films can be joined.

[0013] In a conventional pouch cell, stress caused by gas generated inside the pouch is concentrated on the temporarily attached sealing portion. In this case, the temporarily attached portion can refer to the portion formed from the inner end of the portion to be sealed to a specific internal point. Specifically, the temporarily attached portion can refer to the portion where the pouch is joined by an adhesive material and is relatively weaker compared to the sealing portion. Therefore, in a conventional pouch cell, stress may be concentrated on the temporarily attached portion where the adhesive sealing performance is relatively weak. That is, a conventional pouch cell has the problem that the sealing of the sealing portion is easily damaged due to the pressure of gas from the inside. Additionally, due to this damage, a conventional pouch cell has a high risk of causing exhaust.

[0014] Therefore, there is a need for a new type of pouch cell that can improve the sealing durability to delay or prevent exhaust. Summary of the Invention

[0015] Technical Problem

[0016] One aspect of the present invention provides a pouch cell that can improve the sealing durability of the joint to delay or prevent pouch venting caused by internal gas generated during the charge and discharge of the pouch cell.

[0017] Technical solution

[0018] According to one aspect of the present invention, there is provided a pouch cell according to the present invention, comprising: an electrode assembly; an inner pouch film that covers a part of the electrode assembly; and an outer pouch film that surrounds the outer periphery of the inner pouch film and is combined with the inner pouch film to cover the outer surface of the electrode assembly together with the inner pouch film.

[0019] The inner pouch film may include a first layer 1-1 and a second layer 1-2. The second layer 1-2 is disposed on the opposite side of the electrode assembly with respect to the first layer 1-1, and the outer pouch film includes a first layer 2-1. The first layer 2-1 faces the electrode assembly and is joined to the second layer 1-2 so that the inner pouch film is combined with the outer pouch film.

[0020] The inner pouch film may include: an inner main body; and an inner peripheral portion that is connected to the inner main body at a predetermined angle and extends toward the outer pouch film. The outer pouch film may include: an outer main body; and an outer peripheral portion that is connected to the outer main body at a predetermined angle and extends toward the inner pouch film. The outer periphery of the inner peripheral portion and the inner periphery of the outer peripheral portion may contact and combine.

[0021] The pouch cell may further include an electrode lead that electrically connects the electrode assembly to the outside. A first through hole may be formed in the inner peripheral portion, a second through hole may be formed at a position corresponding to the position of the first through hole in the outer peripheral portion, and the electrode lead may be electrically connected to the outside through the first through hole and the second through hole.

[0022] The inner peripheral portion may extend such that one end contacts the outer main body.

[0023] The length of the extension of the outer peripheral portion may be equal to the length of the extension of the inner peripheral portion.

[0024] The outer pouch film may include: an outer main body; an outer peripheral portion that is connected to the outer main body at a predetermined angle and extends toward the inner pouch film; and a joint portion that is connected to the outer peripheral portion at a predetermined angle and extends in a direction away from the outer peripheral portion. The outer periphery of the inner pouch film and the inner periphery of the joint portion may contact and combine.

[0025] The inner soft packaging film may include: an inner main body portion; and an inner peripheral portion that is connected to the inner main body portion at a predetermined angle and extends toward the outer soft packaging film. The outer periphery of the inner main body portion may contact and bond with the inner periphery of the joint portion, and the outer periphery of the inner peripheral portion may contact and bond with the inner periphery of the outer peripheral portion.

[0026] At least one of the first - second layer and the second - first layer may contain a polyolefin - based resin.

[0027] The polyolefin - based resin may be polypropylene (PP) or polyethylene (PE).

[0028] The outer soft packaging film may include a second - second layer that is disposed on the opposite side of the electrode assembly with respect to the second - first layer, and at least one of the first - first layer and the second - second layer may contain aluminum (Al) or stainless steel (SUS).

[0029] The outer soft packaging film may contain an insulating material and may further include an insulating layer that is disposed on the opposite side of the electrode assembly with respect to the second - second layer.

[0030] The inner soft packaging film may contain a corrosion - resistant material and may further include a corrosion - resistant layer that is disposed between the first - first layer and the electrode assembly.

[0031] The first - first layer may contain a metal, and the first - second layer may contain a polyolefin - based resin.

[0032] The inner soft packaging film and the outer soft packaging film may be in the shape of a box with one side open, and the outer surface of the peripheral portion formed along the edge of one side of the inner soft packaging film may bond with the inner surface of the peripheral portion formed along the edge of one side of the outer soft packaging film.

[0033] Advantageous Effects

[0034] The pouch - type battery cell according to the present invention may include an electrode assembly, an inner soft packaging film covering the electrode assembly, and an outer soft packaging film surrounding the outer periphery of the inner soft packaging film and bonding with the inner soft packaging film.

[0035] Therefore, it is possible to delay or prevent pouch exhaust caused by internal gas generated during the charge and discharge of the pouch - type battery cell.

[0036] In addition, the stress caused by the gas generated inside the pouch is dispersed, thereby delaying or preventing pouch exhaust.

[0037] In addition, the sealing durability of the joint portion can be improved, so that the pouch - type battery cell can have improved safety.

[0038] In addition, the stress caused by the gas generated inside the pouch acts in the planar direction of the joint portion, which can have the effect of improving the joint performance.

[0039] The effects according to the present invention are not limited to the features illustrated in the above examples, and more different effects are included in this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a cross-sectional view schematically showing a cross-section of a conventional pouch cell.

[0041] Figure 2 is a perspective view schematically showing a pouch cell according to an embodiment of the present invention.

[0042] Figure 3 is a perspective view schematically showing an inner soft package film and an outer soft package film according to an embodiment of the present invention.

[0043] Figure 4 is a cross-sectional view schematically showing a part of a pouch cell according to an embodiment of the present invention along Figure 2 A-A' cut.

[0044] Figure 5 is a cross-sectional view schematically showing a part of a pouch cell according to another embodiment of the present invention along Figure 2 A-A' cut.

[0045] Figure 6 is a cross-sectional view schematically showing a part of a pouch cell according to still another embodiment of the present invention along Figure 2 A-A' cut; and

[0046] Figure 7 is a cross-sectional view schematically showing a part of a pouch cell according to still another embodiment of the present invention along Figure 2 A-A' cut. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0047] 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 to which the present invention pertains can easily implement it. However, the present invention can be implemented in many different forms and is not limited to the examples set forth herein.

[0048] To clearly describe the present invention, a detailed description of parts unrelated to the description or related known technologies that may unnecessarily obscure the gist of the present invention has been omitted, and reference numerals are added to the components in each of the drawings in this specification. In this case, throughout the specification, the same or similar reference numerals denote the same or similar elements.

[0049] In addition, the terms or words used in the specification and claims should not be construed restrictively in their ordinary meaning or dictionary-based meaning, but should be construed to have meanings and concepts consistent with the scope of the present invention based on the principle that the inventor can appropriately define the terms so as to describe and explain his or her invention in the best way.

[0050] Figure 2 is a perspective view schematically showing a pouch-type battery cell 10 according to an embodiment of the present invention, and Figure 3 is a perspective view schematically showing an inner soft packaging film 100 and an outer soft packaging film 200 according to an embodiment of the present invention.

[0051] The pouch-type battery cell 10 according to an embodiment of the present invention may include an electrode assembly, an inner soft packaging film 100, and an outer soft packaging film 200. In this case, the pouch-type battery cell 10 described in the present invention may refer to a secondary battery capable of charging and discharging. Specifically, the pouch-type battery cell 10 may refer to a secondary battery in which an electrode assembly including a negative electrode, a positive electrode, and a separator is disposed inside a pouch, and the pouch surrounds the electrode assembly. A conventional pouch-type battery cell may include a pouch formed by molding a cup portion capable of accommodating the electrode assembly in the soft packaging film. In contrast, the pouch-type battery cell 10 according to an embodiment of the present invention may include a pouch in a form different from that of a conventional pouch-type battery cell.

[0052] The inner soft packaging film 100 of the pouch-type battery cell 10 according to an embodiment of the present invention may cover a part of the electrode assembly. Specifically, the inner soft packaging film 100 and the outer soft packaging film 200 may cover the outer surface of the electrode assembly. That is, the outer soft packaging film 200 may cover a part of the outer surface of the electrode assembly that is not covered by the inner soft packaging film 100. Hereinafter, the form of the inner soft packaging film 100 and the outer soft packaging film 200 will be defined as a pouch.

[0053] Referring to Figure 2 and Figure 3 the inner soft packaging film 100 and the outer soft packaging film 200 covering the electrode assembly may be provided to be joined together. Regarding the form of joining the inner soft packaging film 100 and the outer soft packaging film 200, the outer soft packaging film 200 of the pouch-type battery cell 10 according to an embodiment of the present invention may surround the outer periphery of the inner soft packaging film 100 and be joined to the inner soft packaging film 100. That is, a conventional soft packaging film is joined in a manner of surface contact with each other, while the inner soft packaging film 100 and the outer soft packaging film 200 according to an embodiment of the present invention may be joined in a manner of contact between the outer surface of the inner soft packaging film 100 and the inner surface of the outer soft packaging film 200.

[0054] Hereinafter, the shapes of the inner soft packaging film 100 and the outer soft packaging film 200 according to an embodiment of the present invention will be described in more detail.

[0055] Referring to Figure 3, the inner soft package film 100 and the outer soft package film 200 can be box-shaped. In this case, the box shape can represent a generally rectangular shape. Specifically, the inner soft package film 100 and the outer soft package film 200 can be box-shaped with one side open. Based on Figure 3 , the open side of the inner soft package film 100 can be the upper side, and the open side of the outer soft package film 200 can be the lower side.

[0056] A part of the inner soft package film 100 can enter the interior of the outer soft package film 200 through the open side of the outer soft package film 200. In this case, the outer surface of the peripheral part formed along the edge of one side of the inner soft package film 100 can be combined with the inner surface of the peripheral part formed along the edge of one side of the outer soft package film 200. That is to say, the inner soft package film 100 and the outer soft package film 200 can be combined in the form of two boxes with one side open being assembled with each other (see Figure 2 ). When the inner soft package film 100 and the outer soft package film 200 are rectangular, the peripheral part can represent four side parts.

[0057] The electrode assembly can be accommodated in the space formed inside by combining the inner soft package film 100 and the outer soft package film 200.

[0058] Hereinafter, the combination form of the inner soft package film 100 and the outer soft package film 200 according to the embodiments of the present invention will be described in more detail.

[0059] Figure 4 is a cross-sectional view schematically showing a part of the pouch cell 10 according to the embodiment of the present invention cut along the Figure 2 line A-A'.

[0060] Referring to Figure 4 , the inner soft package film 100 of the pouch cell 10 can include a first layer 101 and a second layer 102. In this case, the second layer 102 can be arranged on the opposite side of the electrode assembly with respect to the first layer 101. That is to say, the first layer 101 can be arranged closer to the electrode assembly than the second layer 102.

[0061] The outer soft package film 200 of the pouch cell 10 can include a first layer 201. The first layer 201 of the outer soft package film 200 can face the electrode assembly. In this case, the first layer 201 of the outer soft package film 200 can be joined to the second layer 102 of the inner soft package film 100 so that the inner soft package film 100 and the outer soft package film 200 are combined. Specifically, a part of the first layer 201 of the outer soft package film 200 can be joined to a part of the second layer 102 of the inner soft package film 100.

[0062] In the pouch cell unit 10 according to an embodiment of the present invention, the first to second layer 102 including the outer surface of the inner soft film 100 and the second to first layer 201 including the inner surface of the outer soft film 200 may come into contact with and bond to each other. Accordingly, the stress caused by the gas generated inside the pouch cell unit 10 may act in the planar direction of the inner soft film 100 or the outer soft film 200. That is, the pouch cell unit 10 according to an embodiment of the present invention (in which the stress acts in a form different from that of a conventional pouch cell unit) may improve the pressure resistance inside the pouch cell unit. In addition, the pouch cell unit 10 according to an embodiment of the present invention may be manufactured to be generally rectangular.

[0063] Meanwhile, the method of joining a part of the first to second layer 102 and a part of the second to first layer 201 may vary. For example, a part of the first to second layer 102 and a part of the second to first layer 201 may be joined by a seal applying heat and pressure.

[0064] As an example of a component that may be joined by heat and pressure, the first to second layer 102 and the second to first layer 201 may contain a polyolefin-based resin. For a more specific example, the first to second layer 102 and the second to first layer 201 may contain at least one material selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylene benzobisoxazole), polyarylate, Teflon, and glass fiber. A polyolefin-based resin such as polypropylene (PP) or polyethylene (PE) may be mainly used. In particular, polypropylene may be excellent in mechanical properties (such as tensile strength, stiffness, surface hardness, abrasion resistance, heat resistance) and chemical properties (such as corrosion resistance).

[0065] As an example of a material having a sealing property when heated, when the polyolefin-based resin melts due to heat, the first to second layer 102 and the second to first layer 201 containing the polyolefin-based resin may be joined.

[0066] The inner soft film 100 and the outer soft film 200 according to an embodiment of the present invention may include layers other than the layer containing the polyolefin-based resin. For example, the inner soft film 100 and the outer soft film 200 may include a layer containing a metal.

[0067] In this regard, the outer soft film 200 may include a second to second layer 202 provided on the opposite side of the electrode assembly with respect to the second to first layer 201. That is, the outer soft film 200 may include the second to first layer 201 closer to the electrode assembly provided inside and the second to second layer 202 farther from the electrode assembly than the second to first layer 201.

[0068] In this case, at least one of the 1-1 layer 101 of the inner soft packaging film 100 and the 2-2 layer 202 of the outer soft packaging film 200 may contain aluminum (Al) or stainless steel (SUS). Specifically, the 1-1 layer 101 and the 2-2 layer 202 may contain aluminum (Al) or stainless steel (SUS). Preferably, in order to obtain the stiffness of the inner soft packaging film 100 and the outer soft packaging film 200, the 1-1 layer 101 and the 2-2 layer 202 may contain stainless steel (SUS).

[0069] Meanwhile, another example of the 1-1 layer 101 and the 2-2 layer 202 may further include at least one material selected from the group consisting of iron (Fe), carbon (C), chromium (Cr), manganese (Mn), and nickel (Ni). Since the 1-1 layer 101 of the inner soft packaging film 100 and the 2-2 layer 202 of the outer soft packaging film 200 contain metals, the soft-pack battery cell 10 can obtain stiffness.

[0070] Referring to Figure 4 , the inner soft packaging film 100 according to an embodiment of the present invention may include an inner main body portion 110 and an inner peripheral portion 120. In this case, the inner peripheral portion 120 may be connected to the inner main body portion 110 at a predetermined angle. Additionally, the inner peripheral portion 120 may extend toward the outer soft packaging film 200. Preferably, the angle formed between the inner main body portion 110 and the inner peripheral portion 120 may be approximately 90°.

[0071] The outer soft packaging film 200 may include an outer main body portion 210 and an outer peripheral portion 220. In this case, the outer peripheral portion 220 may be connected to the outer main body portion 210 at a predetermined angle. Additionally, the outer peripheral portion 220 may extend toward the inner soft packaging film 100. Preferably, the angle formed between the outer main body portion 210 and the outer peripheral portion 220 may be approximately 90°.

[0072] The inner main body portion 110 of the inner soft packaging film 100 and the outer main body portion 210 of the outer soft packaging film 200 may generally be in the shape of a plate with a rectangular cross-section and may cover the upper and lower portions of the electrode assembly. Additionally, the inner peripheral portion 120 and the outer peripheral portion 220 may be connected to the four corners of the inner main body portion 110 and the outer main body portion 120 having a generally rectangular cross-section, and may cover the side surfaces of the electrode assembly.

[0073] Referring to Figure 4, the outer periphery of the inner peripheral portion 120 and the inner periphery of the outer peripheral portion 220 may be in contact and bonded. Specifically, the first - second layer 102 of the inner peripheral portion 120 and the second - first layer 201 of the outer peripheral portion 220 may be in contact and bonded. In this case, the first - second layer 102 is a part of the inner soft package 100 formed by a plurality of layers divided into layers, and the inner peripheral portion 120 is a part of the inner soft package 100 divided by the forming position. Therefore, the inner peripheral portion 120 may also include the first - second layer 102. Similarly, the outer peripheral portion 220 may also include the second - first layer 201.

[0074] Meanwhile, the electrode assembly covered by the inner soft package 100 and the outer soft package 200 and accommodated therebetween may generate electrical energy. As an example of a component for transmitting the electrical energy generated by the electrode assembly to the outside, the pouch cell 10 may include an electrode lead 300 (see Figure 2 ).

[0075] The electrode lead 300 may be a conductor and may have various shapes. For example, the electrode lead 300 may have a shape protruding to the outside of the pouch and may have an outer surface disposed on the same plane as the outer surface of the pouch. Additionally, the outer surface of the electrode lead 300 may be disposed more inwardly than the outer surface of the pouch.

[0076] As an example of a component on which the electrode lead 300 may be provided, according to an embodiment of the present invention, a first through - hole 121 may be formed in the inner peripheral portion 120. Additionally, a second through - hole 221 may be formed in the outer peripheral portion 220. In this case, the second through - hole 221 of the outer peripheral portion 220 may be formed at a position corresponding to the position where the first through - hole 121 of the inner peripheral portion 120 is formed (see Figure 1 and Figure 2 ).

[0077] The shapes of the first through - hole 121 and the second through - hole 221 may vary according to the shape of the electrode lead 300. For example, the pouch cell 10 may include an electrode lead 300 having a generally rectangular shape, and the first through - hole 121 and the second through - hole 122 may be formed to have a generally rectangular cross - section.

[0078] When the electrode lead 300 has a shape protruding to the outside of the pouch or has an outer surface disposed on the same plane as the outer surface of the pouch, the electrode lead 300 may pass through the first through - hole 121 and the second through - hole 221.

[0079] The electrode lead 300 may be electrically connected to the outside through the first through - hole 121 and the second through - hole 221.

[0080] When using the pouch cell unit 10, charge and discharge can be repeated, which may cause gas to be generated inside the pouch. The pressure caused by the gas inside the pouch according to an embodiment of the present invention can act on each inner surface of the inner pouch film 100. In this case, the pressure inside the pouch can also act on the side surfaces formed at the four corners along the opening side of the inner pouch film 100. That is, the pressure caused by the gas inside the pouch can be used to enhance the adhesion between the inner pouch film 100 and the outer pouch film 200. In addition, the pressure caused by the gas inside the pouch can act in the planar direction with the joint portion between the inner pouch film 100 and the outer pouch film 200 as a reference. Therefore, the pouch cell unit 10 including the novel pouch can have improved sealing durability, so as to prevent exhaust even under relatively high pressure.

[0081] Hereinafter, a description of components that are the same as those of the pouch cell unit 10 according to an embodiment of the present invention will not be given, and different components will be mainly described.

[0082] Figure 5 is a cross-sectional view schematically showing a part of the pouch cell unit 10 according to another embodiment of the present invention cut along Figure 2 the line A-A'.

[0083] In the pouch cell unit 10 according to another embodiment of the present invention, the shape of the inner peripheral portion 120 of the inner pouch film 100 may be different from that of the above embodiment. In addition, the inner pouch film 100 and the outer pouch film 200 may include another layer.

[0084] Referring to Figure 5 , one end of the inner peripheral portion 120 of the inner pouch film 100 according to another embodiment of the present invention may be in contact with the outer pouch film 200. Specifically, one end of the inner peripheral portion 120 of the inner pouch film 100 may extend and be in contact with the outer main body portion 210 of the outer pouch film 200.

[0085] When one end of the inner peripheral portion 120 extends and is in contact with the outer main body portion 210, most of the pressure caused by the gas inside the pouch can act on the inner peripheral portion 120 in the planar direction. Therefore, the pressure can act in a direction to improve the sealing durability of the inner peripheral portion 120 and the outer peripheral portion 210.

[0086] At the same time, the outer peripheral portion 220 of the outer pouch film 200 may also extend. Preferably, the length (L) by which the outer peripheral portion 220 of the outer pouch film 200 extends may be approximately the same as the length by which the inner peripheral portion 120 of the inner pouch film 100 extends. Referring to Figure 5, the length (L) of the outer peripheral portion 220 extending can be substantially equal to the length of the inner peripheral portion 120 extending. Therefore, the area where the inner peripheral portion 120 and the outer peripheral portion 220 are joined can become larger, thereby increasing the bonding strength between the inner soft package film 100 and the outer soft package film 200.

[0087] The inner soft package film 100 of the pouch cell monomer 10 according to another embodiment of the present invention may further include other layers in addition to the first layer 101 and the second layer 102. Specifically, the inner soft package film 100 may further include a corrosion-resistant layer 103.

[0088] The corrosion-resistant layer 103 of the inner soft package film 100 may contain a corrosion-resistant material. In this case, the corrosion-resistant material may refer to a material having corrosion resistance so as not to be corroded by the electrolyte provided inside the pouch.

[0089] Referring to Figure 5 , the corrosion-resistant layer 103 of the inner soft package film 100 may be provided between the first layer 101 and the electrode assembly. That is, in the inner soft package film 100 according to another embodiment of the present invention, the corrosion-resistant layer 103 may be the layer provided on the innermost surface, and the corrosion-resistant layer 103 may be provided to face the electrode assembly. Therefore, the inner soft package film 100 may be formed in the order of the corrosion-resistant layer 103, the first layer 101, and the second layer 102 from the inside.

[0090] The inner soft package film 100 of the pouch cell monomer 10 according to another embodiment of the present invention further includes the corrosion-resistant layer 103, and thus corrosion of the first layer 101 containing metal can be prevented.

[0091] The outer soft package film 200 of the pouch cell monomer 10 according to another embodiment of the present invention may further include other layers in addition to the first layer 201 and the second layer 202. Specifically, the outer soft package film 200 may further include an insulating layer 203.

[0092] The insulating layer 203 of the outer soft package film 200 may contain an insulating material. In this case, the insulating material may refer to a material that does not conduct electricity or heat.

[0093] For example, the insulating layer 203 may contain at least one material selected from the group consisting of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl chloride, acrylic polymer, polyacrylonitrile, polyimide, polyamide, cellulose, aramid, nylon, polyester, poly(p-phenylene terephthalamide benzoxazole), polyarylate, Teflon, and glass fiber. Mainly, polymers such as nylon resin or polyethylene terephthalate (PET) having wear resistance and heat resistance may be used.

[0094] Referring to Figure 5, the insulating layer 203 of the outer soft package 200 can be disposed on the opposite side of the electrode assembly with respect to the second layer 202. That is, the outer soft package 200 according to another embodiment of the present invention may have the insulating layer 203 disposed on its outermost surface. Thus, the outer soft package 200 may be formed from the inside in the order of the first layer 201, the second layer 202, and the insulating layer 203.

[0095] The outer soft package 200 of the pouch cell 10 according to another embodiment of the present invention further includes an insulating layer 203, so that the second layer 202 containing metal can be insulated from other components. Thus, the insulating layer 203 can prevent an unnecessary short circuit from occurring in the outer soft package 200.

[0096] Figure 6 is a schematic cross-sectional view showing a part of the pouch cell 10 according to still another embodiment of the present invention cut along Figure 2 line A-A'.

[0097] Referring to Figure 6 , the outer soft package 200 of the pouch cell 10 according to another embodiment of the present invention may further include a joining portion 230.

[0098] The joining portion 230 of the outer soft package 200 may be connected to the outer peripheral portion 220 at a predetermined angle and may extend in a direction away from the outer peripheral portion 220. Specifically, the joining portion 230 may extend toward the middle of the pouch. In this case, the angle formed between the outer peripheral portion 220 and the joining portion 230 may be approximately 90°.

[0099] The joining portion 230 extending in a direction away from the outer peripheral portion 220 may be joined to the inner soft package 100. In this regard, the inner soft package 100 according to another embodiment of the present invention may generally be in a plate shape. In this case, referring to Figure 6 , the joining portion 230 may be joined to the lower surface of the inner soft package 100.

[0100] Since the joining portion 230 is joined to the lower surface of the inner soft package 100, the outer soft package 200 can be joined to the inner soft package 100 over a larger area, thereby improving the sealing durability of the pouch cell 10.

[0101] Hereinafter, descriptions of components that are the same as those of the pouch cell 10 according to one embodiment and another embodiment of the present invention will not be given, and different components will be mainly described.

[0102] Figure 7 is a schematic cross-sectional view showing a part of the pouch cell 10 according to still another embodiment of the present invention cut along Figure 2 line A-A'.

[0103] Refer to Figure 7 , when the outer soft envelope 200 includes the joint portion 230, the inner soft envelope 100 may include an inner main body portion 110 and an inner peripheral portion 120.

[0104] Specifically, in the inner soft envelope 100 and the outer soft envelope 200, the outer periphery of the inner main body portion 110 may contact and bond with the inner periphery of the joint portion 230, and the outer periphery of the inner peripheral portion 120 may contact and bond with the inner periphery of the outer peripheral portion 220. In this case, the inner peripheral portion 120 of the inner soft envelope 100 may extend and contact the outer main body portion 210 of the outer soft envelope 200.

[0105] Refer to Figure 7 , the pouch cell monomer 10 according to another embodiment of the present invention may join two parts. Therefore, the sealing performance between the inner soft envelope 100 and the outer soft envelope 200 can be further improved. In this case, the two joined parts may receive pressure from the inside of the pouch in the planar direction.

[0106] Although the present invention has been described through specific embodiments and drawings, the present invention is not limited thereto, and those skilled in the art to which the present invention pertains can make various changes and modifications within the equivalent scope of the technical concept of the present invention and the appended claims.

[0107] [Description of Reference Numerals]

[0108] 10: Pouch cell monomer

[0109] 100: Inner soft envelope

[0110] 101: First layer 1-1

[0111] 102: First layer 1-2

[0112] 103: Corrosion-resistant layer

[0113] 110: Inner main body portion

[0114] 120: Inner peripheral portion

[0115] 121: First through hole

[0116] 200: Outer soft envelope

[0117] 201: Second layer 2-1

[0118] 202: Second layer 2-2

[0119] 203: Insulating layer

[0120] 210: Outer main body portion

[0121] 220: Outer peripheral portion

[0122] 221: Second through-hole

[0123] 230: Joint portion

[0124] 300: Electrode lead

Claims

1. A pouch cell monomer, comprising: An electrode assembly; An inner soft film, the inner soft film covering a part of the electrode assembly; And An outer soft film, the outer soft film surrounding the outer periphery of the inner soft film and bonding with the inner soft film to cover the outer surface of the electrode assembly together with the inner soft film.

2. The pouch cell monomer according to claim 1, wherein The inner soft film includes a first layer 1-1 and a first layer 1-2, the first layer 1-2 being disposed on the opposite side of the electrode assembly with respect to the first layer 1-1, and The outer soft film includes a second layer 2-1, the second layer 2-1 facing the electrode assembly and bonding with the first layer 1-2 such that the inner soft film and the outer soft film are bonded together.

3. The pouch cell monomer according to claim 1, wherein, The inner soft film includes: An inner main body; and An inner peripheral portion, the inner peripheral portion being connected to the inner main body at a predetermined angle and extending toward the outer soft film, and The outer soft film includes: An outer main body; and An outer peripheral portion, the outer peripheral portion being connected to the outer main body at a predetermined angle and extending toward the inner soft film, and The outer periphery of the inner peripheral portion contacts and bonds with the inner periphery of the outer peripheral portion.

4. The pouch cell monomer according to claim 3, further comprising an electrode lead, the electrode lead electrically connecting the electrode assembly to the outside, Among them, A first through hole is formed in the inner peripheral portion, A second through hole is formed at a position corresponding to the position of the first through hole in the outer peripheral portion, and The electrode lead is electrically connected to the outside through the first through hole and the second through hole.

5. The pouch cell monomer according to claim 3, wherein The inner peripheral portion extends such that one end contacts the outer main body.

6. The pouch cell monomer according to claim 5, wherein, The length by which the outer peripheral portion extends is equal to the length by which the inner peripheral portion extends.

7. The pouch cell monomer according to claim 1, wherein, The outer soft film includes: An outer main body; An outer peripheral portion, the outer peripheral portion being connected to the outer main body at a predetermined angle and extending toward the inner soft film; and A bonding portion, the bonding portion being connected to the outer peripheral portion at a predetermined angle and extending in a direction away from the outer peripheral portion, and The outer periphery of the inner soft film contacts and bonds with the inner periphery of the bonding portion.

8. The pouch cell monomer according to claim 7, wherein, The inner soft film includes: An inner main body; and An inner peripheral portion, the inner peripheral portion being connected to the inner main body at a predetermined angle and extending toward the outer soft film, The outer periphery of the inner main body contacts and bonds with the inner periphery of the bonding portion, and The outer periphery of the inner peripheral portion contacts and bonds with the inner periphery of the outer peripheral portion.

9. The soft-pack battery cell according to claim 2, wherein At least one of the first layer 1-2 and the second layer 2-1 contains a polyolefin-based resin.

10. The pouch cell monomer according to claim 9, wherein The polyolefin-based resin is polypropylene (PP) or polyethylene (PE).

11. The pouch cell monomer according to claim 2, wherein, The outer soft film includes a second layer 2-2, the second layer 2-2 being disposed on the opposite side of the electrode assembly with respect to the second layer 2-1, and At least one of the first layer 1-1 and the second layer 2-2 contains aluminum (Al) or stainless steel (SUS).

12. The pouch cell monomer according to claim 11, wherein, The outer soft film contains an insulating material and further includes an insulating layer, the insulating layer being disposed on the opposite side of the electrode assembly with respect to the second layer 2-2.

13. The pouch cell monomer according to claim 2, wherein The inner soft film package contains a corrosion-resistant material and further includes a corrosion-resistant layer, and the corrosion-resistant layer is disposed between the first layer 1-1 and the electrode assembly.

14. The pouch cell monomer according to claim 13, wherein, The first layer 1-1 contains a metal, and The second layer 1-2 contains a polyolefin-based resin.

15. The soft-pack battery cell according to claim 1, wherein, The inner soft film package and the outer soft film package are box-shaped with one side open, and The outer surface of the peripheral portion formed along the edge of one side of the inner soft film package is combined with the inner surface of the peripheral portion formed along the edge of one side of the outer soft film package.

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