Rechargeable battery and battery pack including the same

Abstract

The invention relates to a rechargeable battery and a battery pack including the same. A rechargeable battery includes a case having a sidewall portion including a base layer; and an electrode assembly accommodated in the case. The sidewall portion includes a nanofiber web including cellulose-based nanofibers and a polyolefin-based resin, the cellulose-based nanofibers and the polyolefin-based resin being provided on one or both of an outer peripheral surface of the base layer and an inner peripheral surface of the base layer.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2024-0157282, filed on November 7, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to rechargeable batteries and battery packs including rechargeable batteries. Background Technology

[0004] With the rapid proliferation of electronic devices such as mobile phones, laptops, and electric vehicles, the demand for rechargeable batteries with high energy density and high capacity has increased rapidly. Accordingly, research and development are actively underway to improve the performance of rechargeable batteries, such as rechargeable lithium-ion batteries.

[0005] A rechargeable lithium battery includes a positive electrode and a negative electrode, comprising active materials that allow lithium ions to be inserted into and extracted from the positive and negative electrodes, and an electrolyte. The rechargeable lithium battery generates electrical energy through redox reactions that occur when lithium ions are inserted into and extracted from the positive and negative electrodes.

[0006] The information disclosed in this section serves as the background to this disclosure and may include information that does not constitute prior art or related fields. Summary of the Invention

[0007] This disclosure aims to provide a rechargeable battery (hereinafter, referred to as the "battery") and a battery pack including the rechargeable battery. The rechargeable battery exhibits high stability in the event of an external impact and is capable of suppressing internal fires.

[0008] Rechargeable batteries also have excellent moisture and oxygen barrier properties and can inhibit battery swelling.

[0009] Rechargeable batteries also have excellent electrolyte impregnability.

[0010] However, the purpose of this disclosure is not limited to the purposes mentioned above, and other unmentioned purposes will be clearly understood by those skilled in the art from the following description.

[0011] The rechargeable battery according to this disclosure includes: a housing having a sidewall portion including a base layer; and an electrode assembly housed in the housing, wherein the sidewall portion includes a nanofiber web comprising cellulose nanofibers and a polyolefin resin, the nanofiber web and the polyolefin resin being provided on one or both of an outer peripheral surface and an inner peripheral surface of the base layer.

[0012] The battery pack according to this disclosure includes a housing and a plurality of rechargeable batteries disposed within the housing, wherein each of the plurality of rechargeable batteries includes: a housing having a sidewall portion including a base layer; and an electrode assembly housed in the housing, wherein the sidewall portion includes a nanofiber web comprising cellulose nanofibers and a polyolefin resin, the nanofiber web and the polyolefin resin being provided on one or both of an outer peripheral surface and an inner peripheral surface of the base layer.

[0013] According to this disclosure, because the rechargeable battery includes a casing comprising cellulose nanofibers and polyolefin resins, it exhibits high stability in the event of an external impact, suppresses internal fires, provides excellent moisture and oxygen barrier properties, inhibits battery expansion, and has excellent electrolyte impregnation properties.

[0014] However, the effects that can be obtained through this disclosure are not limited to those described above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the following description. Attached Figure Description

[0015] The accompanying drawings illustrate preferred embodiments of this disclosure by way of example. This disclosure is not limited to the embodiments described in the drawings.

[0016] Figure 1 This is a schematic diagram of a battery pack according to various embodiments of the present disclosure.

[0017] Figure 2 This is a schematic diagram of a rechargeable battery according to an embodiment of the present disclosure.

[0018] Figure 3 This is a cross-sectional view of a rechargeable battery according to an embodiment of the present disclosure.

[0019] Figure 4 This is a cross-sectional view in the thickness direction of the sidewall portion of the casing of a rechargeable battery according to an embodiment of the present disclosure.

[0020] Figure 5 This is a view along the height of the sidewall portion of the casing of a rechargeable battery according to an embodiment of the present disclosure.

[0021] Figure 6 This is a cross-sectional view of the horizontal arrangement of the casing of a rechargeable battery according to an embodiment of the present disclosure.

[0022] Figure 7 A cross-sectional view showing the cross-sectional arrangement in the thickness direction of the sidewall portion of the housing of a rechargeable battery according to another embodiment of the present disclosure.

[0023] Figure 8A cross-sectional view showing the cross-sectional arrangement of the sidewall portion of the housing of a rechargeable battery according to another embodiment of the present disclosure in the thickness direction.

[0024] Figure 9 A cross-sectional view showing the cross-sectional arrangement of the sidewall portion of the housing of a rechargeable battery according to another embodiment of the present disclosure in the thickness direction. Detailed Implementation

[0025] The exemplary embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. The terms or words used in this specification and claims should not be construed as limited to their general or dictionary meanings, and should be interpreted based on the principle that the inventor is able to properly define the terms and concepts to best describe his or her invention, in accordance with the meaning and concept of the technical spirit of this disclosure. Therefore, the embodiments described herein and the configurations shown in the drawings are only some of the most preferred embodiments of this disclosure and do not represent the full technical spirit of this disclosure. Accordingly, it should be understood that various equivalents and modifications may exist to replace these embodiments at the time of filing this application. Furthermore, the expressions “comprise,” “include,” “comprising,” and / or “including” used in this specification indicate the presence of the mentioned shapes, quantities, steps, operations, components, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other shapes, numbers, steps, operations, components, elements, and / or groups thereof. Additionally, in describing embodiments of this disclosure, the expressions “can” and “may” may include “one or more embodiments of this disclosure.”

[0026] Furthermore, to aid in understanding this disclosure, the accompanying drawings are not drawn to scale and some components may be enlarged. Also, in different embodiments, the same reference numerals may be assigned to the same components.

[0027] When it is said that two objects being compared are “identical,” it means that they are “substantially identical.” Substantially identical can include cases where there are small differences (e.g., within 5%) as considered in the art. And when a particular parameter is described as uniform in a predetermined region, this can mean that the parameter is uniform from an average perspective.

[0028] Although terms such as “first” and “second” are used to describe various components, these components are not, of course, limited by these terms. These terms are only used to distinguish one component from another, and, of course, unless otherwise specifically stated, the first component may also be the second component.

[0029] Throughout this instruction manual, unless otherwise specifically stated, each component may be singular or plural.

[0030] When any configuration is described as being set "above (or below)" or "on (or under)" a component, this can mean not only that any configuration is set to contact the upper (or lower) surface of the component, but also that another configuration can be inserted between the component and any configuration set on (or below) the component.

[0031] Furthermore, when a particular component is described as "connected," "linked," or "coupled" to another component, it should be understood that although the components may be directly connected or linked, another component may be "inserted" between the two components, or the two components may be "connected," "linked," or "coupled" through another component. Additionally, when a particular component is described as being electrically connected to another component, this includes not only the case where the two components are directly connected, but also the case where the two components are connected through another device disposed between them.

[0032] Throughout this specification, unless otherwise specifically stated, "A and / or B" means A, B, or A and B. That is, the term "and / or" includes any and all combinations of the listed items. Unless otherwise specifically stated, "C~D" means greater than or equal to C and less than or equal to D.

[0033] When phrases such as “at least one of A, B and C”, “at least one of the group consisting of A, B and C”, and “at least one of A, B and C” are used to specify a list of elements A, B and C, these phrases can indicate any and all appropriate combinations.

[0034] The term “use” can be considered a synonym for the term “utilize”. As used in this specification, the terms “substantially,” “approximately,” and similar terms are used as approximate terms but not as terms of degree, and they are used to take into account the inherent biases of measurements or calculations that are obvious to those skilled in the art.

[0035] Although the terms “first,” “second,” “third,” etc., may be used herein to describe various components, elements, areas, layers, and / or portions, these components, elements, areas, layers, and / or portions should not be limited by these terms. These terms may be used only to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0036] For ease of description, spatial relative terms (such as "below," "below," "down," "above," "upper," etc.) are used herein to describe the relationship between one element or feature illustrated in the accompanying drawings and another element or feature. In addition to the orientations depicted in the drawings, spatial relative terms are intended to encompass different orientations of the device in use or operation. For example, if the device in the drawings is flipped, an element described as "below" or "below" of other elements will be oriented "above" of those other elements. Therefore, the term "below" can encompass both above and below orientations.

[0037] The terminology used in this specification is for describing embodiments of this disclosure and is not intended to limit this disclosure.

[0038] The following description, with reference to the accompanying drawings, describes various embodiments of rechargeable batteries and battery packs including rechargeable batteries according to the present disclosure. For clarity and convenience, the line thicknesses or component dimensions illustrated in the drawings may be enlarged. Furthermore, the terminology used below is defined in consideration of the functions described in this disclosure and may be changed according to the intent of the user or operator or common practice. Therefore, these terms should be defined based on the context of this specification.

[0039] Figure 1 This is a schematic diagram of a battery pack according to various embodiments of the present disclosure.

[0040] refer to Figure 1 According to various embodiments, the battery pack includes a housing 1 and a rechargeable battery 2. The housing 1 forms the exterior of the battery pack and includes a space therein for accommodating the rechargeable battery 2.

[0041] The housing 1 according to this embodiment may include a housing body 11 and a cover 12.

[0042] The outer shell body 11 can be formed as a hollow box with an open side. The cross-sectional shape of the outer shell body 11 is not limited to... Figure 1 The quadrilateral shape is explained in the text and can be changed into various shapes, such as polygonal shapes, circular shapes, and elliptical shapes.

[0043] Cover 12 can be attached to housing body 11 and can enclose the space inside housing body 11. Cover 12 can be formed in a substantially plate-like shape and can face the opening side of housing body 11. Cover 12 can be fixed to housing body 11 using various types of connection methods such as bolting, welding and fitting.

[0044] Each of the rechargeable batteries 2 can be used as a unit structure for storing and supplying power in the battery pack.

[0045] Multiple rechargeable batteries 2 can be provided. The rechargeable batteries 2 can be arranged within the housing 1 in various patterns (such as grid patterns and zigzag patterns). The rechargeable batteries 2 can be arranged parallel to each other. The number of rechargeable batteries 2 can vary depending on the size, shape, etc. of the housing 1. The detailed configuration of the rechargeable batteries 2 will be described below.

[0046] Multiple rechargeable batteries 2 can be electrically connected via busbars (not illustrated). The rechargeable batteries 2 can be connected in series or in parallel via the busbars. For example, the busbars can connect rechargeable batteries 2 arranged in the same row within the housing 1 in parallel, and can connect rechargeable batteries 2 arranged in two adjacent rows in series. The busbars can be formed of a conductive material (such as copper, aluminum, or nickel).

[0047] Figure 2 This is a schematic diagram of a rechargeable battery according to a first embodiment of the present disclosure, and Figure 3 This is a cross-sectional view of a rechargeable battery according to a first embodiment of the present disclosure.

[0048] refer to Figure 2 and Figure 3 The rechargeable battery 2 according to this embodiment may include a housing 100, an electrode assembly 200, and a cover assembly 300.

[0049] The following describes an example in which the rechargeable battery 2 is a cylindrical lithium-ion rechargeable battery. However, this disclosure is not limited thereto. In other examples according to this disclosure, the rechargeable battery 2 may be, for example, a lithium polymer battery, and may be, for example, a prismatic battery.

[0050] The housing 100 may form the exterior of the rechargeable battery 2. The housing 100 may be conductive. The housing 100 may be formed of one or more metallic materials, such as steel, stainless steel, aluminum, and aluminum alloys. The housing 100 may protect the electrode assembly 200 from external impacts and may also serve a heat dissipation function, releasing the heat generated during the charging and discharging operation of the electrode assembly 200 to the outside of the housing 100.

[0051] The housing 100 may include a sidewall portion 110, which is formed in a cylindrical shape and has a central axis C formed in its central portion. The central axis C of the housing 100 indicates the central axis of the sidewall portion 110. The two ends of the sidewall portion 110 perpendicular to the central axis C of the housing 100 may be open. In this document, the direction parallel to the central axis C is referred to as the "vertical direction" or "height direction," and the direction perpendicular to the central axis C is referred to as the "horizontal direction."

[0052] The housing 100 may further include a bottom portion 120 that closes the lower end of the sidewall portion 110. The bottom portion 120 may be substantially disk-shaped and may be positioned facing the lower end of the sidewall portion 110. The bottom portion 120 may be positioned perpendicular to the central axis C of the housing 100. The peripheral surface of the bottom portion 120 may be attached to the lower end of the sidewall portion 110. The bottom portion 120 may be integrally formed with the sidewall portion 110 by a drawing process or the like. Alternatively, in other embodiments, the bottom portion 120 may be formed separately from the sidewall portion 110 and then attached to the sidewall portion 110 by welding or the like.

[0053] The housing 100 may further include an opening 130 at the upper end of the sidewall portion 110. The opening 130 allows the electrode assembly 200 to be inserted into the housing 100 and provides space in which the cover assembly 300 is mounted in the upper region of the housing 100. The opening 130 may indicate a blank space surrounded by the upper region provided by the sidewall portion 110 opposite to the bottom portion 120.

[0054] The electrode assembly 200 can be used as a unit structure in the rechargeable battery 2 for charging and discharging operations. The electrode assembly 200 may include a first electrode plate 210, a second electrode plate 220, and a separator 230 disposed between the first electrode plate 210 and the second electrode plate 220. The electrode assembly 200 may be disposed within the housing 100. The electrode assembly 200 can be inserted into the housing 100 through the opening 130 of the housing 100.

[0055] The electrode assembly 200 may be wound around a winding axis. More specifically, the electrode assembly 200 may be formed by stacking a first electrode plate 210, a diaphragm 230, and a second electrode plate 220, and then winding it clockwise or counterclockwise around a winding axis. Accordingly, the electrode assembly 200 may have a substantially core-like form. The cross-sectional shape of the electrode assembly 200 is not limited to a circular shape and may be various other shapes (such as elliptical and polygonal shapes). The winding axis may be a straight line passing through the central portion of the electrode assembly 200. The winding axis of the electrode assembly 200 may be coaxial with the central axis C of the housing 100.

[0056] The first electrode plate 210 can be used as the positive electrode of the electrode assembly 200. The first electrode plate 210 can be formed from a foil structure including a metallic material (such as aluminum or an aluminum alloy). The type, size, shape, etc. of the first electrode plate 210 are not limited, as long as the first electrode plate 210 does not cause undesirable chemical changes in the rechargeable battery 2 and is conductive.

[0057] The first active material layer may be provided on at least a portion of the first electrode plate 210. More specifically, the first active material layer may be provided on both surfaces of the first electrode plate 210, or may be provided only on one surface of the first electrode plate 210.

[0058] Since the first electrode plate 210 serves as the positive electrode, the first active material layer may include a positive electrode active material. The positive electrode active material may be a compound capable of reversibly intercalating and deintercalating lithium (lithiated intercalation compound). Some examples of the positive electrode active material may be one or more compounds of lithium and a metal selected from cobalt, manganese, nickel, iron, and combinations thereof. In a specific example, the positive electrode active material may include lithium iron phosphate (LiFePO4, LFP), lithium manganese iron phosphate (LiMnFePO4, LMFP), and lithium nickel cobalt manganese composite oxide (LiNi x Co y Mn z O2, LNCM, where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1) and at least any one of them. The positive electrode active material may include lithium iron phosphate (LiFePO4, LFP), lithium manganese iron phosphate (LiMnFePO4, LMFP), and lithium nickel cobalt manganese composite oxide (LiNi x Co y Mn z O2, LNCM, where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1), or may include lithium iron phosphate (LiFePO4, LFP), lithium manganese iron phosphate (LiMnFePO4, LMFP), and lithium nickel cobalt manganese composite oxide (LiNi x Co y Mn z O2, LNCM, where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1) and any two or all of them.

[0059] The first active material layer may further include a positive electrode conductive additive. The positive electrode conductive additive is used to impart conductivity to the first active material layer, and any conductive material that does not cause an undesirable chemical change can be used as the positive electrode conductive additive. Examples of the positive electrode conductive additive include: carbonaceous materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube); metallic materials in the form of metal powder or metal fiber and containing copper, nickel, aluminum, silver, etc.; conductive polymers (such as poly(phenylene) derivatives); or mixtures thereof.

[0060] The first active material layer may further include a positive electrode binder. The positive electrode binder is used to ensure that the particles constituting the positive electrode active material adhere to each other, and is used to ensure that the positive electrode active material adheres to the first electrode plate 210.

[0061] As a positive electrode binder, non-aqueous binders, aqueous binders, dry binders, or combinations thereof can be used.

[0062] Examples of non-aqueous adhesives include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, or combinations thereof.

[0063] Waterborne adhesives may be styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acryloyl rubber, butyl rubber, fluorinated rubber, polyethylene oxide, polyvinylpyrrolidone, polyepoxychloropropane, polyphosphazene, poly(meth)acrylonitrile, ethylene-propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acryloyl resin, phenolic resin, epoxy resin, polyvinyl alcohol, or combinations thereof.

[0064] When the aqueous binder is used as the positive electrode binder, it may further include a cellulose compound that imparts viscosity. One or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and their alkali metal salts may be used as cellulose compounds. Na, K, or Li may be used as the alkali metal.

[0065] Dry adhesives are polymeric materials that can be formed into fibers, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or combinations thereof.

[0066] The first electrode plate 210 can be electrically connected to the cover assembly 300. Since the first electrode plate 210 serves as the positive electrode of the electrode assembly 200, the cover assembly 300 can serve as the positive electrode terminal of the rechargeable battery 2. The first electrode plate 210 can be electrically connected to the cover assembly 300 via a first electrode contact E1. The first electrode contact E1 can comprise a conductive metallic material (such as copper, copper alloy, nickel, or nickel alloy). The first electrode contact E1 can be disposed on the upper side of the electrode assembly 200, and its end can be connected to the first electrode plate 210 and the cover assembly 300. One end of the first electrode contact E1 can be directly connected to the first electrode plate 210, or indirectly connected to the first electrode plate 210 via a separate current collector connected to the first electrode plate 210. However, the first electrode plate 210 is not limited to this configuration and can be directly connected to the cover assembly 300 without the first electrode contact E1.

[0067] The second electrode plate 220 can be used as the negative electrode of the electrode assembly 200. The second electrode plate 220 can be formed of a foil including a metallic material such as copper, copper alloy, nickel, or nickel alloy. The second electrode plate 220 can be spaced apart from the first electrode plate 210 by a predetermined distance and face the first electrode plate 210.

[0068] The type, size, shape, etc. of the second electrode plate 220 are not limited as long as the second electrode plate 220 does not cause an undesirable chemical change in the rechargeable battery 2 and has electrical conductivity.

[0069] The second active material layer can be provided on at least a part of the second electrode plate 220. The second active material layer can be provided on both surfaces of the second electrode plate 220, or can be provided only on one surface of the second electrode plate 220.

[0070] Since the second electrode plate 220 serves as the negative electrode, the second active material layer can include a negative electrode active material. The negative electrode active material can include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, a lithium metal alloy, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0071] The material capable of reversibly intercalating / deintercalating lithium ions can be a carbon-based negative electrode active material and can include, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon include graphite (such as natural graphite or artificial graphite) having an irregular shape, plate shape, sheet shape, spherical shape, or fibrous shape, and examples of amorphous carbon include soft carbon, hard carbon, mesophase pitch carbide, and calcined coke.

[0072] The alloy of lithium metal can include an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0073] The Si-based negative electrode active material and / or the Sn-based negative electrode active material can be used as the material capable of doping and dedoping lithium. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiO x (x = 1 or 2), a Si-Q alloy, or a combination thereof. In the formula Si-Q, Q is selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements (excluding Si), Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof. The Sn-based negative electrode active material can be Sn, SnO k (0 < k ≤ 2, for example, SnO2), a Sn-based alloy, or a combination thereof.

[0074] The silicon-carbon composite can be a composite of silicon and amorphous carbon. According to embodiments, the silicon-carbon composite can take the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the silicon-carbon composite particles may include secondary particles (cores) in which primary silicon particles are aggregated and an amorphous carbon coating (shell) located on the surface of the secondary particles. The amorphous carbon may also be located between the primary silicon particles. For example, the primary silicon particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0075] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles, and an amorphous carbon coating on the surface of the core.

[0076] Si-based and / or Sn-based negative electrode active materials can be mixed with carbon-based negative electrode active materials.

[0077] The second active material layer may further include a negative electrode conductive additive and a negative electrode binder.

[0078] Negative electrode conductive additives are used to impart conductivity to the second active material layer, and any conductive material that does not cause undesirable chemical changes can be used as a negative electrode conductive additive. Examples of negative electrode conductive additives include: carbon-based materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes); metallic materials in the form of metal powders or metal fibers and containing copper, nickel, aluminum, silver, etc.; conductive polymers (such as polyphenylene derivatives); or mixtures thereof.

[0079] The negative electrode binder is used to ensure that the particles constituting the negative electrode active material adhere to each other and to ensure that the negative electrode active material is adhered to the second electrode plate 220.

[0080] As a negative electrode binder, non-aqueous binders, aqueous binders, dry binders, or combinations thereof can be used.

[0081] Examples of non-aqueous adhesives include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, or combinations thereof.

[0082] The waterborne adhesive can be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acryloyl rubber, butyl rubber, fluorinated rubber, polyethylene oxide, polyvinylpyrrolidone, polyepoxychloropropane, polyphosphazene, poly(meth)acrylonitrile, ethylene-propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acryloyl resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0083] When the aqueous binder is used as a negative electrode binder, it may further include a cellulose compound that imparts viscosity. One or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and their alkali metal salts may be used as cellulose compounds. Na, K, or Li may be used as the alkali metal.

[0084] Dry adhesives are polymeric materials that can be formed into fibers. Dry adhesives may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or combinations thereof.

[0085] The second electrode plate 220 can be electrically connected to the housing 100. For example, the second electrode plate 220 can be electrically connected to the housing 100 via the second electrode connector E2. Since the second electrode plate 220 can be used as the negative electrode of the electrode assembly 200, the housing 100 can be used as the negative electrode terminal of the rechargeable battery 2. The second electrode connector E2 can include a conductive metallic material (such as copper, copper alloy, nickel, or nickel alloy). The second electrode connector E2 can be disposed on the underside of the electrode assembly 200, and its end is connected to the second electrode plate 220 and the bottom portion 120 of the housing 100. One end of the second electrode connector E2 can be directly connected to the second electrode plate 220, or indirectly connected to the second electrode plate 220 via a separate current collector connected to the second electrode plate 220. However, the second electrode plate 220 is not limited to this configuration and can be directly connected to the housing 100 without the second electrode connector E2.

[0086] A separator 230 may be disposed between the first electrode plate 210 and the second electrode plate 220. The separator 230 prevents short circuits between the first electrode plate 210 and the second electrode plate 220 while allowing lithium ions to move between them. A polyethylene separator, a polypropylene separator, a polyvinylidene fluoride separator, or two or more multilayer membranes thereof (such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polypropylene triple-layer separator, and a polypropylene / polypropylene / polypropylene triple-layer separator) may be used as the separator 230.

[0087] The diaphragm 230 may include a porous substrate and a coating located on one or both surfaces of the porous substrate and may include an organic material, an inorganic material, or a combination thereof.

[0088] The porous substrate may be a polymer membrane formed from any one of the following polymers or copolymers or mixtures thereof: polyolefins (such as polyethylene or polypropylene), polyesters (such as polyethylene terephthalate or polybutylene terephthalate), polyacetal, polyamide, polyimide, polycarbonate, polyetherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene ether, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fiber, and polytetrafluoroethylene (e.g., Teflon). ® ).

[0089] Organic materials may include polymers such as polyvinylidene fluoride or (meth)acrylic acid polymers.

[0090] Inorganic materials may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof. However, this disclosure is not limited to these examples.

[0091] Organic and inorganic materials can be formed in a single coating. In other embodiments, coatings comprising organic materials and coatings comprising inorganic materials can be stacked.

[0092] The diaphragm 230 can be provided as a pair of diaphragms 230. The pair of diaphragms 230 can be configured to face the surfaces of the first electrode plate 210 and / or the second electrode plate 220. The pair of diaphragms 230 can be wound together with the first electrode plate 210 and the second electrode plate 220 around a winding shaft.

[0093] The first insulating plate 201 and the second insulating plate 202 may be disposed on both sides of the electrode assembly 200. The first insulating plate 201 and the second insulating plate 202 may include insulating materials such as rubber, polyethylene (PE), polypropylene (PP) and polyethylene terephthalate (PET).

[0094] According to this embodiment, the first insulating plate 201 can be a substantially disk-shaped structure. The first insulating plate 201 can be disposed between the upper surface of the electrode assembly 200 and the cover assembly 300. Accordingly, the first insulating plate 201 can prevent the upper surface of the electrode assembly 200 from contacting the cover assembly 300 and can insulate the electrode assembly 200 and the cover assembly 300 from each other. A through-hole (not illustrated) through which the first electrode terminal E1 extends can be formed in the first insulating plate 201.

[0095] The second insulating plate 202 may be a substantially disk-shaped structure. The second insulating plate 202 may be disposed between the lower surface of the electrode assembly 200 and the bottom portion 120 of the housing 100. Accordingly, the second insulating plate 202 prevents the lower surface of the electrode assembly 200 from contacting the bottom portion 120 of the housing 100 and insulates the electrode assembly 200 and the bottom portion 120 of the housing 100 from each other. A through-hole (not illustrated) through which the second electrode tab E2 extends may be formed in the second insulating plate 202.

[0096] The cover assembly 300 can be coupled to the housing 100 and can seal the opening 130 of the housing 100. For example, the cover assembly 300 can be disposed on the upper end of the side wall portion 110. A rolled portion 140 recessed toward the central axis C of the housing 100 can be formed on the side wall portion 110. The rolled portion 140 can be disposed on the lower side of the cover assembly 300 and can limit the extent to which the cover assembly 300 is inserted into the housing 100. A rolled edge portion 150 bent toward the central axis C of the housing 100 at the upper end of the side wall portion 110 can be formed on the upper side of the rolled portion 140. The rolled edge portion 150 can prevent the cover assembly 300 from falling off to the outside of the housing 100.

[0097] The cover assembly 300 may include an upper cover 310, a lower cover 320, a vent plate 330, an extension 340, and a contact portion 350.

[0098] The upper cover 310 forms the upper external appearance of the cover assembly 300 and can be placed in the opening portion 130. A cover hole 311 can be formed in the upper cover 310 for venting gases generated inside the housing 100 to the outside of the housing 100. The upper cover 310 can be electrically connected to the first electrode plate 210 via the lower cover 320 and the exhaust plate 330.

[0099] The lower cover 320 may face the upper cover 310 and may be electrically connected to the electrode assembly 200. A lower cover hole 321 extending through the lower cover 320 may be formed in the lower cover 320.

[0100] The exhaust plate 330 can be arranged between the upper cover 310 and the lower cover 320.

[0101] An extension 340 may extend from the exhaust plate 330 and connect to the top cover 310. The extension 340 may support the exhaust plate 330 relative to the top cover 310 and provide an electrical connection between the top cover 310 and the exhaust plate 330.

[0102] The extension 340 according to this embodiment may include a support portion 341 and a hinge portion 342. The support portion 341 forms part of the outer surface of the extension 340 and is connectable to the top cover 310. The hinge portion 342 forms another part of the outer surface of the extension 340 and is disposed between the support portion 341 and the exhaust plate 330. The hinge portion 342 allows the support portion 341 and the exhaust plate 330 to connect to each other and causes deformation of the exhaust plate 330 when the internal pressure of the housing 100 increases.

[0103] The contact portion 350 can protrude from the exhaust plate 330 toward the lower cover 320 and contact the lower cover 320.

[0104] The rechargeable battery 2 according to this embodiment may further include a cutout 360 and a recess 370. The recess 370 may be recessed from the vent plate 330 toward the contact portion 350. The recess 370 reduces the thickness of the central region of the vent plate 330, thereby allowing the vent plate 330 to deform smoothly when the internal pressure of the housing 100 increases.

[0105] A gasket G may be disposed between the housing 100 and the cover assembly 300. The gasket G, through its elastic restoring force, secures the cover assembly 300 in the position of the opening portion 130, electrically insulates the housing 100 and the cover assembly 300 from each other, and prevents moisture or electrolyte from flowing in or out between the housing 100 and the cover assembly 300. The gasket G may comprise an insulating material such as rubber, polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). The gasket G may be formed in a substantially annular shape and may be disposed on the inner side of the rolled portion 140 and / or the crimped portion 150. The outer side surface of the gasket G may contact the inner side surface of the rolled portion 140 and / or the crimped portion 150. The inner side surface of the gasket G may contact the outer side surface of the cover assembly 300.

[0106] The gasket G may be disposed on the inner side of the coiled portion 140 and / or the crimped portion 150. The cover assembly 300 may be electrically connected to the first electrode plate 210 via the first electrode terminal E1. Since the first electrode plate 210 serves as the positive electrode of the electrode assembly 200, the cover assembly 300 may serve as the positive electrode terminal of the rechargeable battery 2.

[0107] When the pressure inside the housing 100 increases due to overcurrent or the like, the cover assembly 300 can block the electrical connection between the rechargeable battery 2 and the external device. When the pressure inside the housing 100 increases, the cover assembly 300 can rupture, opening the space inside the housing 100 to the space outside. Accordingly, the cover assembly 300 can reduce the risk of the rechargeable battery 2 exploding in the event of an overcurrent.

[0108] Figures 4-6The configuration of the housing of a rechargeable battery according to an embodiment of the present disclosure is shown. Figure 4 This is a cross-sectional view in the thickness direction of the sidewall portion of the casing of a rechargeable battery according to an embodiment of the present disclosure. Figure 5 This is a view along the height of the sidewall portion of the casing of a rechargeable battery according to an embodiment of the present disclosure. Figure 6 This is a cross-sectional view of the horizontal arrangement of the casing of a rechargeable battery according to an embodiment of the present disclosure.

[0109] refer to Figures 4-6 The sidewall portion 110 of the housing 100 includes a base layer 110a. The base layer 110a may form part of the sidewall portion 110 of the housing 100 and may support another part of the sidewall portion 110 of the housing 100. The base layer 110a may include at least one or more metallic materials selected from steel, stainless steel, aluminum, and aluminum alloys. However, this disclosure is not limited to these examples.

[0110] Base layer 110a may have 50 µm or larger (specifically, 50 µm, 55 µm, 60 µm, 65 µm, 70 µm, 75 µm, 80 µm, 85 µm, 90 µm, 95 µm, 100 µm, 105 µm, 110 µm, 115 µm, 120 µm, 125 µm, 130 µm, 135 µm, 140 µm, 145 µm, 150 µm, 155 µm, 160 µm, 165 µm, 170 µm, 175 µm, 180 µm, 185 µm, 190 µm, 195 µm, 200 µm, 205 µm, 210 µm, 215 µm, 220 µm, 225 µm, 230 µm, 235 µm, 240 µm, 245 The thickness L1 is 110a, ranging from 10 µm to 250 µm and from 50 µm to 250 µm. Within this range, the substrate layer 110a can withstand the expansion of the battery during the charge-discharge cycle.

[0111] The substrate 110a has an outer peripheral surface A and an inner peripheral surface B opposite to the outer peripheral surface A. The inner peripheral surface B of the substrate 110a may face the electrode assembly 200, and the outer peripheral surface A of the substrate 110a may face away from the electrode assembly 200.

[0112] refer to Figure 4Cellulose nanofibers 111 (hereinafter referred to as "cellulose nanofibers") and polyolefin resin 112 (hereinafter referred to as "polyolefin resin") can be provided on the outer peripheral surface A of the substrate layer 110a. Cellulose nanofibers 111 can increase the strength of the sidewall portion 110 of the housing 100, thereby increasing stability in the event of an external impact. Cellulose nanofibers 111 can also suppress fire within the battery.

[0113] In this embodiment, the cellulose nanofiber 111 may be a crystalline cellulose nanofiber. Crystalline cellulose nanofibers have higher strength than amorphous cellulose nanofibers and further increase the strength of the casing 100, thereby increasing the stability against external impacts and suppressing fire within the battery. Crystalline cellulose nanofibers can be manufactured using methods known to those skilled in the art.

[0114] Cellulose nanofibers may include hydroxyl groups. These hydroxyl groups enhance the adhesion between cellulose resins during nanofiber network formation and increase the strength of the nanofiber network. Therefore, hydroxyl groups can increase resistance to external impacts and suppress fire within the battery.

[0115] Cellulose nanofibers may be nanofibers comprising cellulose resins or cellulose resin derivatives. Cellulose resin derivatives include cellulose ether resins and / or cellulose ester resins.

[0116] In this embodiment, the cellulose nanofibers may be nanofibers comprising a cellulose resin, wherein the cellulose resin comprises repeating units of chemical formula 1:

[0117] [Chemical Formula 1]

[0118]

[0119] Cellulose resins comprising repeating units of Formula 1 above may include hydroxyl groups. For example, cellulose resins may have C2 hydroxyl, C3 hydroxyl and / or C6 hydroxyl (hydroxyl groups at the C2, C3 and / or C6 positions).

[0120] In another embodiment, the cellulose nanofibers may be nanofibers comprising one or more of cellulose ether resins and cellulose ester resins, wherein any one of the hydroxyl groups at the C2, C3, and C6 positions in the repeating unit of Formula 1 above is replaced by an ether group or an ester group. The cellulose ether resins and cellulose ester resins may also have hydroxyl groups.

[0121] Cellulose nanofibers can have an average length that is significantly longer than their average diameter. In embodiments, cellulose nanofibers may have an average diameter of 50 nm or less (e.g., 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm, 30 nm, 31 nm, 32 nm, 33 nm, 34 nm, 35 nm, 36 nm, 37 nm, 38 nm, 39 nm, 40 nm, 41 nm, 42 nm, 43 nm, 44 nm, 45 nm, 46 nm, 47 nm, 48 nm, 49 nm, 50 nm), an average diameter greater than 0 nm but 50 nm or less, and a diameter in the range of 1 nm to 50 nm (1 nm, 2 nm, 3 nm, 4 nm, 50 nm). The average diameter of (5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26 nm, 27 nm, 28 nm, 29 nm, 30 nm, 31 nm, 32 nm, 33 nm, 34 nm, 35 nm, 36 nm, 37 nm, 38 nm, 39 nm, 40 nm, 41 nm, 42 nm, 43 nm, 44 nm, 45 nm, 46 nm, 47 nm, 48 nm, 49 nm, 50 nm), or the average diameter in the range of 5 nm to 50 nm. Cellulose nanofibers can have an average length exceeding 1 µm, for example, an average length in the range of 1 µm to 1,000 µm, or an average length in the range of 10 µm to 1,000 µm.

[0122] Here, "average diameter" refers to the average measured diameter of cellulose nanofibers, and may refer to the general diameter when the cellulose nanofibers have a circular cross-section, and may also refer to the longest length of the cross-section of the cellulose nanofibers when the cross-section is non-circular. "Average length" may refer to the average measured length of cellulose nanofibers.

[0123] Some hydroxyl groups in cellulose nanofibers can be modified to be hydrophobic. This modification can help address the rusting problem caused by the hydroxyl groups in cellulose nanofibers (described below). Furthermore, this modification can also improve electrolyte impregnation properties.

[0124] Cellulose nanofibers modified to have hydrophobic properties can be formed by modifying cellulose nanofibers with silane compounds. For example, cellulose nanofibers and silane compounds can be mixed and then subjected to heat treatment.

[0125] Silane compounds may include one or more of the following: epoxy-containing silane coupling agents, amino-containing silane coupling agents, vinyl-containing silane coupling agents, mercapto-containing silane coupling agents, and alkyl-containing silane coupling agents. Epoxy-containing silane coupling agents may include one or more of epoxycyclohexylpropyltrimethoxysilane and epoxycyclohexylpropyltriethoxysilane, but this disclosure is not limited thereto. Amino-containing silane coupling agents may include one or more of aminopropyltrimethoxysilane and aminopropyltriethoxysilane, but this disclosure is not limited thereto. Vinyl-containing silane coupling agents may include one or more of vinyltrimethoxysilane and vinyltriethoxysilane, but this disclosure is not limited thereto. Mercapto-containing silane coupling agents may include one or more of mercaptopropyltrimethoxysilane and mercaptopropyltriethoxysilane, but this disclosure is not limited thereto. Alkyl-containing silane coupling agents may include one or more of methyltrimethoxysilane, ethyltrimethoxysilane, methylethyldimethoxysilane, and methylethyldiethoxysilane, but this disclosure is not limited thereto. In this document, "containing...group" has the same meaning as "including...group".

[0126] Even after repeated charge-discharge cycles in batteries with electrolytes, these silane coupling agents can remain in cellulose-based nanofibers for an extended period of time.

[0127] Cellulose nanofibers can take the form of a nanofiber network made of cellulose nanofibers located on the outer peripheral surface A of the substrate layer 110a. The nanofiber network can enhance the adhesion between the cellulose nanofibers, thereby further increasing the strength of the shell 100.

[0128] Nanofiber webs can be formed using methods known to those skilled in the art. In one embodiment, the nanofiber web can be prepared by electrospinning an electrospinning solution comprising one or more of cellulose resins, cellulose ether resins, and cellulose ester resins.

[0129] Electrospinning can be performed by preparing an electrospinning solution comprising a predetermined solvent and one or more of cellulose resins, cellulose ether resins, and cellulose ester resins. The spinning of the electrospinning solution can be carried out under an electric field through a nozzle of an electrospinning apparatus.

[0130] Cellulose nanofibers can increase the strength of the nanofiber web by possessing hydroxyl groups. However, cellulose nanofibers can also damage the shell 100 by absorbing moisture or oxygen. Specifically, when the base layer 110a of the shell 100 is made of the aforementioned metal, rust can occur due to external moisture or oxygen. To prevent this problem, a polyolefin resin can be provided together with the cellulose nanofibers on the outer peripheral surface A of the base layer 110a. The polyolefin resin can prevent damage to the shell 100 caused by the hydroxyl groups of the cellulose nanofibers. In addition, the combination of cellulose nanofibers and polyolefin resin can provide a barrier against moisture and oxygen, thereby increasing the sealing effect.

[0131] Polyolefin resins may include one or more of polyethylene resins (such as low-density polyethylene and high-density polyethylene) and polypropylene resins. For example, the polyolefin resin may be a polypropylene resin. Polypropylene resins prevent damage to the housing 100 and provide excellent insulation.

[0132] A mixture of cellulose nanofibers and polyolefin resins can be provided on the outer peripheral surface A of the substrate layer 110a. In an embodiment, based on a 100 wt% mixture, cellulose nanofibers may be included in 70 wt% to 90 wt% of the mixture (e.g., 70 wt, 71 wt, 72 wt, 73 wt, 74 wt, 75 wt, 76 wt, 77 wt, 78 wt, 79 wt, 80 wt, 81 wt, 82 wt, 83 wt, 84 wt, 85 wt, 86 wt, 87 wt, 88 wt, 89 wt, 90 wt%), and may be included in 10 wt% to 30 wt% of the mixture (e.g., 10 wt, 11 wt, 12 wt, 13 wt, 14 wt, 15 wt, 16 wt, 17 wt, 18 wt, 19 wt, 20 wt, 21 wt, 22 wt, 23 wt, 24 wt, 25 wt, 26 wt, 27 wt). The content (wt%, 28 wt%, 29 wt%, 30 wt%) includes polyolefin resins. Within this range, cellulose nanofibers are sufficient to form a nanofiber network and improve the strength of the shell 100. Furthermore, the polyolefin resins prevent rusting caused by the hydroxyl groups of the cellulose nanofibers.

[0133] In an example embodiment, a polyolefin resin and cellulose nanofibers impregnated in the polyolefin resin (e.g., a nanofiber web of cellulose nanofibers) are provided on the outer peripheral surface A of the substrate layer 110a. In this case, the nanofiber web can be stably located on the outer peripheral surface A of the substrate layer 110a, and the nanofiber web is not easily separated from the housing 100 even during battery charge-discharge. Therefore, the battery's lifespan and stability are ensured.

[0134] Refer again Figure 4 The sidewall portion 110 of the housing 100 includes an outer layer 110b located on the outer peripheral surface A of the base layer 110a. The outer layer 110b may surround the outer peripheral surface A of the base layer 110a and may extend from the opening portion 130 of the housing 100 to the bottom portion 120 of the housing 100. The outer layer 110b may include a polyolefin resin 112 and a nanofiber web of cellulose nanofibers 111 impregnated in the polyolefin resin 112. The nanofiber web of cellulose nanofibers 111 may extend from the portion 130a of the sidewall portion 110 that contacts the opening portion 130 of the housing 100 to the portion 120a of the sidewall portion 110 that contacts the bottom portion 120 of the housing 100.

[0135] In embodiments, the nanofiber network (e.g., a portion thereof) of cellulose nanofibers may have porosity. Here, "porosity" refers to a state in which the cellulose nanofibers are coated with a polyolefin resin, and open spaces exist between the cellulose nanofibers. Porosity can increase battery stability by reducing the pressure applied to the nanofiber network during repeated charging and discharging of the battery. In addition, porosity can increase electrolyte impregnation.

[0136] In one embodiment, the outer layer 110b may have a region formed solely of a polyolefin resin without cellulose nanofibers. Here, "a region formed solely of a polyolefin resin without cellulose nanofibers" can refer to a region present in the outer layer 110b that comprises only a polyolefin resin and no cellulose nanofibers. This region can further increase battery stability by reducing the stress applied to the nanofiber network during repeated charging and discharging of the battery.

[0137] The thickness L2 of the outer layer 110b can be less than the thickness L1 of the base layer 110a. Therefore, the structural stability of the battery can be increased by increasing the battery's strength. The thickness L2 of the outer layer 110b can be 10% to 30% of the thickness L1 of the base layer 110a, for example, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, or 10% to 20%. Within this range, the aforementioned effects of the outer layer 110b can be easily achieved. In the example, the thickness L2 of the outer layer 110b can be 50 µm or less, for example, the thickness L2 can be more than 0 µm and 50 µm or less, or it can be 1 µm to 50 µm, and the thickness L1 of the base layer 110a can be 50 µm or more, for example, 50 µm to 250 µm.

[0138] Figures 4-6 The illustration shows a configuration in which cellulose nanofibers and polyolefin resins are located on the outer peripheral surface A of the sidewall portion 110 of the housing 100. However, this disclosure is not limited thereto. Cellulose nanofibers and polyolefin resins may be located on the outer peripheral surface A of the bottom portion 120 of the housing 100. Cellulose nanofibers and polyolefin resins may be as described above. In a specific example, an electrolyte may be included between the electrode assembly 200 and the sidewall portion 110 of the housing 100, and cellulose nanofibers and polyolefin resins may be located on the inner peripheral surface B of the sidewall portion 110 of the housing 100.

[0139] Figure 7 A cross-sectional view showing the cross-sectional arrangement in the thickness direction of the sidewall portion of the housing of a rechargeable battery according to another embodiment of the present disclosure.

[0140] refer to Figure 7 Cellulose nanofibers 111 and polyolefin resin 112 are provided on the inner peripheral surface B of the base layer 110a. Here, the sidewall portion 110 of the shell 100 includes an inner layer 110c located on the inner peripheral surface B of the base layer 110a. The configuration of the cellulose nanofibers and polyolefin resin can be the same as those described above, and the configuration of the inner layer 110c can be the same as those described above. Figures 4-6 The outer layer 110b is described as the same.

[0141] Cellulose nanofibers can be modified to be hydrophobic. Specifically, as described above, cellulose nanofibers can be modified with one or more of the following: silane coupling agents containing epoxy groups, silane coupling agents containing vinyl groups, silane coupling agents containing mercapto groups, silane coupling agents containing amino groups, and silane coupling agents containing alkyl groups, thereby further increasing their electrolyte impregnation properties.

[0142] Nanofiber webs (e.g., a portion thereof) made of cellulose nanofibers can have porosity. Porosity can increase electrolyte impregnation.

[0143] The thickness L3 of the inner layer 110c can be less than the thickness L1 of the base layer 110a. In this configuration, the structural stability of the battery can be increased by increasing the battery strength.

[0144] The thickness L3 of the inner layer 110c can be 10% to 30% (10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%) of the thickness L1 of the base layer 110a, for example, 10% to 20%. Within this range, the aforementioned effects of the inner layer 110c can be easily achieved.

[0145] In some embodiments, thickness L3 of inner layer 110c may be 50 µm or less (e.g., 1 µm, 2 µm, 3 µm, 4 µm, 5 µm, 6 µm, 7 µm, 8 µm, 9 µm, 10 µm, 11 µm, 12 µm, 13 µm, 14 µm, 15 µm, 16 µm, 17 µm, 18 µm, 19 µm, 20 µm, 21 µm, 22 µm, 23 µm, 24 µm, 25 µm, 26 µm, 27 µm, 28 µm, 29 µm, 30 µm, 31 µm, 32 µm, 33 µm, 34 µm, 35 µm, 36 µm, 37 µm, 38 µm, 39 µm, 40 µm, 41 µm, 42 µm, 43µm, 44 µm, 45 µm, 46 µm, 47 (µm, 48 µm, 49 µm, 50 µm), thickness L3 can exceed 0 µm and be 50 µm or smaller, or can be 1 µm to 50 µm. The thickness L1 of the base layer 110a may be 50 µm or greater (eg, 50 µm, 55 µm, 60 µm, 65 µm, 70 µm, 75 µm, 80 µm, 85 µm, 90 µm, 95 µm, 100 µm, 105 µm, 110 µm, 115 µm, 120 µm, 125 µm, 130 µm, 135 µm, 140 µm, 145 µm, 150 µm, 155 µm, 160 µm, 165 µm, 170 µm, 175 µm, 180 µm, 185 µm, 190 µm, 195 µm, 200 µm, 205 µm, 210 µm, 215 µm, 220 µm, 225 µm, 230 µm, 235 µm, 240 µm, 245 µm, 250 µm), 50 µm~250 µm.

[0146] Figure 7 An example is shown in which cellulose nanofibers and polyolefin resin are located on the inner peripheral surface B of the sidewall portion 110 of the housing 100. However, this disclosure is not limited thereto, and the cellulose nanofibers and polyolefin resin may be located on the inner peripheral surface (not shown) of the bottom portion 120 of the housing 100. In other embodiments, the cellulose nanofibers and polyolefin resin may be located on both the inner peripheral surface B of the sidewall portion 110 of the housing 100 and the outer peripheral surface A of the sidewall portion 110 of the housing 100.

[0147] Figure 8 A cross-sectional view showing the cross-sectional arrangement of the sidewall portion of the housing of a rechargeable battery according to another embodiment of the present disclosure in the thickness direction.

[0148] refer to Figure 8 The sidewall portion 110 of the housing 100 includes an inner layer 110c located on the inner peripheral surface B of the base layer 110a and an outer layer 110b located on the outer peripheral surface A of the base layer 110a. The configuration of the outer layer 110b is consistent with the above reference. Figures 4-6 The configuration of the outer layer 110b is basically the same as described above. The configuration of the inner layer 110c is the same as the above reference. Figure 7 The configuration of the inner 110c described is basically the same.

[0149] Figure 8 An embodiment is shown in which cellulose nanofibers and polyolefin resins are located on the outer peripheral surface A and inner peripheral surface B of the sidewall portion 110 of the housing 100. However, this disclosure is not limited thereto, and cellulose nanofibers and polyolefin resins may be located on, for example, the inner peripheral surface and outer peripheral surface of the bottom portion 120 of the housing 100.

[0150] Contains ceramic coating (e.g., Figure 9 A ceramic coating 110d may be further formed between the base layer 110a and the inner layer 110c of the sidewall portion 110. The ceramic coating prevents deformation of the inner layer 110c and increases the sealing performance of the housing 100.

[0151] The ceramic coating may consist solely of ceramics. Ceramics may include metal oxides, quasi-metal oxides, metal fluorides, metal hydroxides, or combinations thereof. For example, inorganic fillers forming the ceramic may include Al₂O₃, SiO₂, TiO₂, SnO₂, CeO₂, MgO, NiO, CaO, GaO, ZnO, ZrO₂, Y₂O₃, SrTiO₃, BaTiO₃, Mg(OH)₂, boehmite, or combinations thereof. However, this disclosure is not limited to these examples.

[0152] The ceramic coating may include ceramic and an adhesive. The adhesive may increase the adhesion between the ceramic coating and the inner peripheral surface B of the inner layer 110c and the base layer 110a.

[0153] Figure 9 A cross-sectional view showing the cross-sectional arrangement of the sidewall portion of the housing of a rechargeable battery according to another embodiment of the present disclosure in the thickness direction.

[0154] refer to Figure 9 The sidewall portion 110 of the housing 100 includes a ceramic-containing coating 110d and an inner layer 110c provided on the inner peripheral surface B of the base layer 110a. The inner layer 110c comprises cellulose nanofibers and a polyolefin resin, which are similar to those described above. Figures 4-6 The descriptions are essentially the same.

[0155] The ceramic coating 110d may consist only of the ceramics described above, or it may include both ceramics and an adhesive.

[0156] According to this disclosure, the rechargeable battery includes a casing comprising cellulose nanofibers and polyolefin resin. As a result, the battery exhibits high stability against external impacts, suppresses internal fires, provides excellent moisture and oxygen barrier properties to inhibit battery expansion, and has excellent electrolyte impregnation properties.

[0157] However, the beneficial effects that can be obtained through this disclosure are not limited to those mentioned above, and other unmentioned beneficial effects will be clearly understood by those skilled in the art from the above description.

[0158] The present disclosure has been described above with reference to the embodiments illustrated in the accompanying drawings, but the present disclosure is not limited to those embodiments. Those skilled in the art will understand that various modifications and other equivalent embodiments can be made therefrom. Furthermore, the present disclosure can also be used in other fields.

Claims

1. A rechargeable battery, comprising: A housing having a sidewall portion including a base layer; and The electrode assembly is housed within the housing. The sidewall portion comprises a nanofiber web containing cellulose nanofibers and a polyolefin resin, the nanofiber web and the polyolefin resin being provided on one or both of the outer peripheral surface and the inner peripheral surface of the substrate.

2. The rechargeable battery of claim 1, wherein the polyolefin resin is a polypropylene resin.

3. The rechargeable battery of claim 1, wherein the nanofiber mesh is impregnated in the polyolefin resin.

4. The rechargeable battery of claim 1, wherein the cellulose nanofibers are crystalline cellulose nanofibers.

5. The rechargeable battery of claim 1, wherein the cellulose nanofibers include hydroxyl groups.

6. The rechargeable battery of claim 5, wherein the cellulose nanofibers comprise cellulose resins or cellulose resin derivatives.

7. The rechargeable battery of claim 5, wherein some of the hydroxyl groups in the cellulose nanofibers are modified to be hydrophobic.

8. The rechargeable battery of claim 7, wherein the cellulose nanofibers modified to be hydrophobic are modified with a silane compound.

9. The rechargeable battery of claim 8, wherein the silane compound comprises: The silane coupling agent includes one or more of the following: epoxy-based silane coupling agents, amino-based silane coupling agents, vinyl-based silane coupling agents, mercapto-based silane coupling agents, and alkyl-based silane coupling agents.

10. The rechargeable battery of claim 1, wherein the cellulose nanofibers and the polyolefin resin are in the form of a mixture, and The mixture comprises 100 wt% of the cellulose nanofibers, which are 70 wt% to 90 wt% of the mixture, and 10 wt% to 30 wt% of the polyolefin resin.

11. The rechargeable battery of claim 1, wherein the sidewall portion comprises an outer layer provided on the outer peripheral surface of the substrate layer. The outer layer surrounds the outer peripheral surface of the base layer and extends from the opening of the housing to the bottom portion of the housing. The outer layer comprises the polyolefin resin, and the nanofiber web made of the cellulose nanofibers is impregnated in the polyolefin resin. The outer layer of nanofiber mesh extends from the opening portion of the housing to the bottom portion of the housing.

12. The rechargeable battery of claim 11, wherein the outer layer comprises a region consisting only of the polyolefin resin and free of the cellulose nanofibers.

13. The rechargeable battery of claim 11, wherein a portion of the nanofiber web of the outer layer has pores.

14. The rechargeable battery of claim 1, wherein the sidewall portion comprises an inner layer located on the inner peripheral surface of the base layer. The inner layer covers the inner peripheral surface of the base layer and extends from the opening of the housing to the bottom portion of the housing; The inner layer comprises the polyolefin resin and the nanofiber web made of the cellulose nanofibers impregnated in the polyolefin resin, and The inner layer of nanofiber mesh extends from the opening portion of the housing to the bottom portion of the housing.

15. The rechargeable battery of claim 14, wherein the inner layer comprises a region consisting only of the polyolefin resin and free of the cellulose nanofibers.

16. The rechargeable battery of claim 14, wherein a portion of the nanofiber network in the inner layer has pores.

17. The rechargeable battery of claim 14, wherein a ceramic coating is provided between the base layer and the inner layer.

18. The rechargeable battery of claim 14, wherein the sidewall portion further comprises an outer layer located on the outer peripheral surface of the base layer. The outer layer covers the outer peripheral surface of the base layer and extends from the opening of the housing to the bottom portion of the housing. The outer layer comprises the polyolefin resin and the nanofiber web made of the cellulose nanofibers impregnated in the polyolefin resin, and The nanofiber web extends from the opening portion of the housing to the bottom portion of the housing.

19. The rechargeable battery of claim 1, wherein the substrate layer comprises at least one selected from steel, stainless steel, aluminum, and aluminum alloys.

20. A battery pack, comprising: shell; and Multiple rechargeable batteries are housed within the casing. Each of the plurality of rechargeable batteries is as described in any one of claims 1 to 19.

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