Battery comprising safety functional layer

Abstract

A battery including a safety functional layer is disclosed. A battery according to various embodiments of the present disclosure may include: a battery case dividing an interior and an exterior of the battery; and an electrode assembly including at least one positive electrode located inside the battery case, at least one negative electrode located inside the battery case to face the positive electrode, and at least one separator disposed between the positive electrode and the negative electrode. The positive electrode may include a positive electrode safety functional layer disposed in a region including an outermost positive electrode region that is closest to an inner side of the battery case in the positive electrode.

Description

Technical Field

[0001] Various embodiments disclosed herein relate to batteries, and more particularly, to batteries including a safety functional layer. Background Art

[0002] With the development of portable electronic devices and electric vehicles, batteries capable of storing and outputting electrical energy are widely used. Lithium-ion batteries are secondary batteries that are lightweight and have high energy density and good charge / discharge characteristics, and are widely used in fields such as portable electronic devices, electric vehicles, and energy storage systems (ESS). Lithium-ion batteries include a negative electrode that releases lithium ions into an electrolyte during discharge, a positive electrode that accepts lithium ions in an oxidized state during discharge (lithium ions are released from the negative electrode), and a separator that prevents direct contact between the negative electrode and the positive electrode.

[0003] Lithium-ion batteries may be subject to various damages, such as external pressure, impact, and / or penetration. When such damages result in contact between the negative electrode and the positive electrode, a short circuit current may occur, which may result in heating, fire, or thermal runaway or fire from the reaction of the positive electrode and / or negative electrode active materials. Various safety measures are being actively pursued and implemented to reduce the risk of fire in lithium-ion batteries. Summary of the invention

[0004] Technical Solution

[0005] In order to reduce the risk of fire, the positive electrode of the battery may include various positive electrode safety functional layers. In addition, the negative electrode of the battery may include various negative electrode safety functional layers. However, since the volume of the entire battery cell including the positive electrode and the negative electrode is increased due to the positive electrode safety functional layer and / or the negative electrode safety functional layer, the power density and energy density of the battery may be reduced. In addition, some positive electrode safety functional layers may increase the internal resistance and thus lead to a further reduction in power density.

[0006] Various embodiments disclosed herein may provide batteries with improved stability and energy density.

[0007] The battery according to various embodiments of the present disclosure may include a battery case and an electrode assembly, the battery case being configured to divide the inside and outside of the battery, the electrode assembly including at least one positive electrode located inside the battery case, at least one negative electrode located inside the battery case to face the positive electrode, and at least one separator located between the positive electrode and the negative electrode. The positive electrode may include a positive electrode safety function layer located in an area including the outermost positive electrode region and closest to the inner surface of the battery case among the regions of the positive electrode.

[0008] In various embodiments, the battery may be a wound type battery in which the electrode assembly is wound in an overlapping manner, and the positive electrode, the negative electrode, and the separator may be wound such that the outermost positive electrode region is positioned toward the outside of the battery.

[0009] In various embodiments, within the region of the positive electrode, the positive electrode safety functional layer may extend from the outermost positive electrode region to at least a portion of the internal positive electrode region, which is a region wound in a space positioned toward the interior of the battery, and the positive electrode safety functional layer may be configured such that, within the region of the positive electrode, the thickness of the positive electrode safety functional layer disposed in the outermost positive electrode region is thicker than the thickness of the positive electrode safety functional layer extending to the internal positive electrode region.

[0010] In various embodiments, the thickness of the positive electrode safety functional layer may decrease in a stepwise manner toward the interior of the battery.

[0011] In various embodiments, the thickness of the positive electrode safety functional layer may continuously decrease toward the inside of the battery.

[0012] In various embodiments, the battery may be a stacked type battery obtained by alternately stacking a plurality of positive electrodes, a plurality of negative electrodes, and a plurality of separators.

[0013] The outermost positive electrode regions may correspond to positive electrodes located at uppermost and lowermost layers among the plurality of stacked positive electrodes.

[0014] In various embodiments, the positive electrode safety functional layer can be further disposed in at least a portion of an internal positive electrode region corresponding to the positive electrode stacked between the outermost positive electrode regions, and the positive electrode safety functional layer can be configured such that, among the regions of the positive electrode, the thickness of the positive electrode safety functional layer disposed in the outermost positive electrode region is thicker than the thickness of the positive electrode safety functional layer disposed in the internal positive electrode region.

[0015] In various embodiments, the thickness of the positive electrode safety functional layer may gradually decrease toward the interior of the battery.

[0016] In various embodiments, the positive electrode may include a positive electrode current collector and a positive electrode active material located on a surface of the positive electrode current collector.

[0017] The positive electrode safety functional layer may be located between the positive electrode current collector and the positive electrode active material.

[0018] In various embodiments, the positive electrode may include a positive electrode current collector and a positive electrode active material located on a surface of the positive electrode current collector.

[0019] The positive electrode safety functional layer may coat the surface of the positive electrode active material.

[0020] In various embodiments, the positive electrode safety functional layer may include a positive temperature coefficient (PTC) material.

[0021] In various embodiments, the PTC material may include a polymer composite material.

[0022] In various embodiments, the positive electrode safety functional layer may include a phosphate-based olivine material.

[0023] In various embodiments, the battery may include a short circuit protection layer that is disposed in the battery case and is spaced apart from the outermost positive electrode region while surrounding at least a portion of the outer peripheral surface of the outermost positive electrode region, the short circuit protection layer being electrically connected to the negative electrode and having a conductive material.

[0024] In various embodiments, the width of the short protection layer may be narrower than the width of the outermost positive electrode region.

[0025] In various embodiments, the battery may further include a negative electrode safety functional layer disposed in a region of the negative electrode corresponding to a region of the positive electrode where the positive electrode safety functional layer is disposed.

[0026] According to various embodiments of the present disclosure, a battery may include a battery case configured to divide the inside and outside of the battery, at least one positive electrode located inside the battery case, at least one negative electrode located inside the battery case to face the positive electrode, at least one separator located between the positive electrode and the negative electrode, and a safety function layer located in at least one of the positive electrode and the negative electrode. The thickness of the safety function layer may increase toward a position relatively closer to the outside of the battery.

[0027] In various embodiments, the safety functional layer may be disposed in the positive electrode and may include a positive temperature coefficient (PTC) material.

[0028] In various embodiments, the PTC material may include a polymer composite material.

[0029] In various embodiments, the safety functional layer may be disposed in the positive electrode and may include a phosphate-based olivine material.

[0030] According to various embodiments disclosed herein, due to the positive electrode safety function layer disposed in a region close to the case (or pouch) of the battery, a battery having improved safety against external penetration and improved energy density and power density may be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In conjunction with the description of the drawings, the same or similar reference numerals may be used for the same or similar components.

[0032] Figure 1a The structure of a battery according to various embodiments is schematically shown.

[0033] Figure 1b The structure of a battery according to various embodiments is schematically shown.

[0034] Figure 1c The structure of a battery according to various embodiments is schematically shown.

[0035] Figure 2a is a schematic diagram showing a cross section of a stacked battery according to various embodiments.

[0036] Figure 2b 2 is a schematic diagram showing a cross section of a wound type battery according to various embodiments.

[0037] Figure 2c Shows Figure 2b The state of the winding component being unfolded.

[0038] Figure 3a to Figure 3c is an enlarged cross-sectional view showing an outermost positive electrode region of a battery according to various embodiments.

[0039] Figures 4a to 4d is a cross-sectional view of a battery according to various embodiments.

[0040] Figure 5 is a cross-sectional view of a battery according to various embodiments. DETAILED DESCRIPTION

[0041] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In these drawings, for example, for the convenience and clarity of explanation, the size and shape of the components may be exaggerated, and changes in the shapes shown may be expected during actual implementation. Therefore, the embodiments of the present disclosure should not be interpreted as being limited to the specific shapes of the regions shown in this specification.

[0042] Reference numerals in the drawings refer to the same elements throughout the drawings.In addition, as used herein, the term "and / or" includes any and all combinations of any one or more of the listed items.

[0043] The embodiments of the present disclosure are provided to more completely explain the present disclosure to those skilled in the art, and the following embodiments may be modified in various forms and the scope of the present disclosure is not limited to the embodiments described herein. More specifically, these embodiments are provided to make the present disclosure more complete and thorough, and to fully convey the spirit of the present disclosure to those skilled in the art.

[0044] The terms used herein are only used to describe the embodiments and are not intended to limit the scope of the present disclosure. In addition, even if the singular is described herein, plural indicators may be included unless the context clearly specifies otherwise. In addition, the terms "comprising" and / or "comprising ... " as used herein specify the presence of stated features, numbers, steps, operations, components, elements and / or groups thereof, but do not exclude the presence or addition of other features, numbers, operations, components, elements and / or groups thereof. In addition, it will be understood by those skilled in the art that a structure or shape that is "adjacent" to another feature may have a portion that overlaps with or is disposed under an adjacent feature.

[0045] In this specification, relative terms such as "below", "above", "up", "lower", "horizontal" or "vertical" may be used to describe the relationship of one element, layer or region to another element, layer or region, as depicted in the figures. It should be understood that these terms encompass directions other than those depicted in the figures.

[0046] Figure 1a to Figure 1c The structure of a battery according to various embodiments is schematically shown.

[0047] refer to Figure 1a to Figure 1c , the battery 100 (e.g., a stacked battery 100a, a cylindrical battery 100b, or a jelly roll battery 100c) may include a positive electrode 160, a negative electrode 150, and a separator 170. The positive electrode 160 may be an electrode that acts as a cathode when the battery 100 is discharged and absorbs lithium ions from an electrolyte included in the battery 100 to form a lithium compound and acts as an anode when the battery 100 is charged and releases lithium ions. The positive electrode may include a positive electrode current collector and a positive electrode active material, and the positive electrode current collector includes a metal foil such as aluminum. The positive electrode active material may include a lithium compound, for example, an olivine-type compound such as lithium cobalt oxide (LixCoO 2 ), lithium nickel oxide (LixNiO 2 ), lithium nickel cobalt oxide (Lix(NiCo)O 2 ), lithium nickel cobalt manganese oxide (Lix(NiCoMn)O 2 ), lithium nickel cobalt aluminum oxide (Lix(NiCoAl)O 2 ), spinel lithium manganese oxide (LixMn 2 O 4 ), manganese dioxide (MnO 2 ), lithium iron phosphate (LixFePO 4 ) and / or lithium manganese phosphate (LixMnPO 4 ).

[0048] The negative electrode 150 may be an electrode that acts as an anode when the battery 100 is discharged to release lithium ions through an electrolyte included in the battery 100 and acts as a cathode when the battery 100 is charged to store reduced lithium atoms. The negative electrode 150 may include a negative electrode current collector and a negative electrode active material, the negative electrode current collector including a metal foil such as copper. The negative electrode active material may include, for example, various silicon-based compounds (such as artificial and / or natural graphite, silicon oxide, silicon nitride, and / or silicon carbide) that store lithium by intercalation and / or lithium metal that stores metal phase lithium or various alloys or metal compounds thereof.

[0049] The separator 170 may be a member that prevents electrical contact between the positive electrode 160 and the negative electrode 150 while allowing lithium ions to pass therethrough. In some embodiments, the separator 170 may include a polymer material such as polyethylene or polypropylene having micropores of a size that allow lithium ions to pass therethrough. The minimum unit of the battery 100 including the negative electrode 150, the positive electrode 160, and the separator 170 may be referred to as an electrode assembly.

[0050] The battery case 180 (e.g., battery case 180a, battery case 180b, or battery case 180c) may be a container having an internal space in which the negative electrode 150, the positive electrode 160, and the separator 170 are wound, folded, or stacked and accommodated. For example, the battery case 180 may include a metal (e.g., aluminum or stainless steel), a polymer material, and / or a composite or laminate thereof. An organic electrolyte (not shown) may be injected and sealed into the battery case 180. For example, the organic electrolyte may include a lithium salt and an organic solvent. The lithium salt may be LiPF 6 , LiBF 4 、LiSbF 6 、LiAsF 6 、LiN(SO 2 C 2 F 5 ) 2 、Li(CF 3 SO 2 ) 2 N、LiN(SO 3 C2F 5 ) 2 ,LiC 4 F 9 SO 3 、LiClO 4 、LiAlO 2 、LiAlCl 4 , LiCl, LiI and LiB(C 2 O 4 ) 2, or a mixture thereof. For example, the organic solvent may include cyclic carbonates (such as ethylene carbonate, butylene carbonate or vinylene carbonate), linear carbonates (such as dimethyl carbonate, ethyl methyl carbonate or diethyl carbonate), acetate compounds (such as methyl acetate, ethyl acetate or propyl acetate), and fluorinated organic compounds thereof (wherein at least one hydrogen atom is substituted by fluorine (F)).

[0051] refer to Figure 1a The battery 100 according to various embodiments may be a stacked type battery 100a in which at least one electrode assembly is stacked and positioned in an inner space of a battery case 180a. The battery case 180a may be, for example, a square can or a soft pouch.

[0052] refer to Figure 1b , the battery 100 according to various embodiments may be a cylindrical battery 100b in which at least one electrode assembly is wound and positioned in the inner space of a battery case 180b. The battery case 180b may be, for example, a cylindrical or similar cylindrical can.

[0053] refer to Figure 1c , the battery 100 according to various embodiments may be a jelly roll type battery 100c in which at least one electrode assembly is wound with a stadium-shaped cross section and positioned in the inner space of a battery case 180c. The battery case 180c may be, for example, a square can or a soft bag. The cylindrical battery 100b and the jelly roll type battery 100c share the same characteristics in which the battery cells are wound and positioned within the battery cases 180b, 180c, and therefore may be collectively referred to as "wound type" batteries 100b, 100c.

[0054] Figure 2a is a schematic diagram illustrating a cross section of a stacked battery 200 a according to various embodiments.

[0055] Figure 2b 2 is a schematic diagram illustrating a cross section of a wound type battery 200 b according to various embodiments.

[0056] Figure 2c It shows Figure 2b The state of the winding component being unfolded.

[0057] Figure 2a The cross section can be, for example, along Figure 1a A cross section taken along line AA'.

[0058] Figure 2b The cross section can be, for example, along Figure 1b The cross section is taken along the line BB'.

[0059] refer to Figure 2a , stacked battery 200a (eg, Figure 1aThe stacked battery 100a may include at least one negative electrode 220 having a plate shape and sequentially stacked on each other, at least one separator 230, and at least one positive electrode 210. In the at least one positive electrode 210, a region of the positive electrode 210 closest to the outside of the stacked battery 200a (for example, located Figure 2a The area in the direction indicated by EX in the stacked battery 200a) can be defined as the "outermost positive electrode area 210a". For example, in the stacked battery 200a, the area closest to the outside of the stacked plate-shaped positive electrode 210, for example, the area located at the uppermost layer and the lowermost layer among the stacked positive electrodes 210, can be defined as the outermost positive electrode area 210a. In the stacked battery 200a, the positive electrode 210 stacked between the outermost positive electrode areas 210a can be defined as the inner positive electrode area 210b. The detailed configuration of the positive electrode 210 will be described later.

[0060] refer to Figure 2b and Figure 2c , a wound battery 200b (eg, Figure 1b or Figure 1c The wound type battery 100b, 100c) may include a negative electrode 220, a separator 230, and a positive electrode 210 having a plate shape and sequentially stacked on each other, and may be configured in which the negative electrode 220, the separator 230, and the positive electrode 210 are wound in a spiral shape and from the center to the outside (for example, in Figure 2b In the region of the positive electrode 210, the positive electrode 210 (for example, in the direction indicated by EX) overlaps the structure. Figure 2b The area closest to the outside of the battery (in the direction indicated by EX in FIG. 1 ) may be defined as the "outermost positive electrode area 210a", and in the wound battery 200b, the outermost wound area may be defined as the outermost positive electrode area 210a. In the wound battery 200b, the area wound inside the outermost positive electrode area 210a may be defined as the inner positive electrode area 210b.

[0061] exist Figure 2b and Figure 2c Only cylindrical batteries (eg, Figure 1b ), but it will be apparent to those skilled in the art that the description of the wound battery 200b according to various embodiments of the present disclosure is applicable not only to cylindrical batteries, but also to jelly roll batteries (e.g., Figure 1c jelly roll battery 100c).

[0062] refer to Figure 2a to Figure 2c, the positive electrode 210 may include a positive electrode safety functional layer 213 disposed at least in the outermost positive electrode region 210a of the positive electrode 210. In the event of damage due to factors such as penetration and / or pressure from the outside, the positive electrode safety functional layer 213 may be provided when the negative electrode 220 of the battery is in contact with the positive electrode active material (e.g., Figure 3a of positive electrode active material 212) and / or a positive electrode current collector (e.g., Figure 3a A positive electrode current collector 211) is a member that reduces the risk of fire or other unsafe situations when in direct contact with the positive electrode current collector 211, which will be described later. In various embodiments, the positive electrode safety function layer 213 may be provided in a region including the outermost positive electrode region 210a and other regions of the positive electrode 210 and in the outermost positive electrode region 210a. This will be described later.

[0063] Within the battery 200 (e.g., battery 200a or battery 200b), the area with a relatively high risk of damage due to puncture and / or pressure is the area near the outside of the battery 200. Therefore, by placing at least the positive electrode safety functional layer 213 in the outermost positive electrode region 210a of the positive electrode 210, the risk of damage from the outside can be effectively reduced. In addition, the adverse effect on the energy density and / or power density of the battery caused by the positive electrode 210 including more positive electrode safety functional layers 213 can be reduced by not placing the positive electrode safety functional layer 213 in the inner positive electrode region 210b or placing the positive electrode safety functional layer 213 in a smaller amount.

[0064] In reference Figure 2a to Figure 2c In various embodiments, the negative electrode 220 may include a negative electrode safety functional layer 223, which is disposed in a region of the negative electrode 220 corresponding to a region of the positive electrode 210 in which the positive electrode safety functional layer 213 is disposed.

[0065] Figure 3a to Figure 3c is an enlarged cross-sectional view showing an outermost positive electrode region of a battery according to various embodiments.

[0066] refer to Figure 3a to Figure 3c , a positive electrode 210 (eg, Figure 1a to Figure 1c The positive electrode 160 ) may include a positive electrode current collector 211 , a positive electrode active material 212 , and a positive electrode safety function layer 213 .

[0067] The positive electrode current collector 211 may be a member configured to collect charges generated by the positive electrode active material 212 and supply power to the outside of the battery or receive power from the outside to charge the battery. In various embodiments, the current collector may include a plate-shaped metal, particularly a metal such as aluminum having high electrochemical stability in the electrode reaction potential region of the positive electrode active material 212.

[0068] The positive electrode active material 212 may be Figure 3b As shown, it is positioned to at least partially contact the surface of the positive electrode current collector 211, or it can be as shown. Figure 3a The positive electrode active material 212 may be a material that is received from the negative electrode 220 (eg, Figure 1a to Figure 1c The positive electrode active material 212 may be, for example, an olivine-type compound such as lithium cobalt oxide (LixCoO 2 ), lithium nickel oxide (LixNiO 2 ), lithium nickel cobalt oxide (Lix(NiCo)O 2 ), lithium nickel cobalt manganese oxide (Lix(NiCoMn)O 2 ), lithium nickel cobalt aluminum oxide (Lix(NiCoAl)O 2 ), spinel lithium manganese oxide (LixMn 2 O 4 ), manganese dioxide (MnO 2 ), lithium iron phosphate (LixFePO 4 ) and / or lithium manganese phosphate (LixMnPO 4 ).

[0069] The positive electrode safety functional layer 213 may be a layer that reduces the risk of fire or other unsafe situations occurring due to a short circuit current and / or a chemical reaction occurring when the positive electrode 210 contacts a negative electrode (eg, the negative electrode 220 of FIG. 2 ).

[0070] refer to Figure 3a , the positive electrode safety functional layer 213 according to various embodiments may be a first positive electrode safety functional layer 213a disposed between the positive electrode current collector 211 and the positive electrode active material 212. Figure 3b According to various embodiments, the positive electrode safety functional layer 213 may be a second positive electrode safety functional layer 213b located on a surface of the positive electrode active material 212, the surface of the positive electrode active material 212 facing the surface where the positive electrode current collector 211 and the positive electrode active material 212 contact each other. Figure 3cThe positive electrode safety functional layer 213 according to various embodiments may be a third positive electrode safety functional layer 213 c coating a surface of the particulate positive electrode active material 212 located on a surface of the positive electrode current collector 211 .

[0071] The positive electrode safety functional layer 213 of various embodiments (eg, the first positive electrode safety functional layer 213a, the second positive electrode safety functional layer 213b, or the third positive electrode safety functional layer 213c) may include an olivine phosphate material such as LiFePO 4 and / or LiMnPO 4 The positive electrode safety functional layer 213 including the olivine phosphate material has relatively high chemical stability when in contact with the material constituting the negative electrode 220, and thus can prevent chemical reactions and heat generation due to contact between the positive electrode 210 and the negative electrode 220 in the event of damage such as penetration from outside the battery.

[0072] In various embodiments, the positive electrode safety functional layer 213 may include a PTC material. The PTC material may be a material having a positive thermal coefficient (PTC) of resistivity. In various embodiments, the positive electrode safety functional layer 213 may include a PTC ceramic or a PTC polymer composite material. The PTC ceramic may include a perovskite-based ceramic, such as rare earth-doped BaTiO 3 The PTC polymer composite may include a polymer matrix and conductive particles such as carbon black dispersed in the polymer matrix, and may be a material whose conductivity decreases or increases due to expansion or contraction of the polymer matrix according to temperature. The polymer matrix may include materials such as high-density polyethylene (HDPE), polymethyl methacrylate (PMMA), ethylene vinyl acetate (EVA), and / or polyvinylidene fluoride (PVDF).

[0073] When a short-circuit current flows due to direct contact between the positive electrode 210 and the negative electrode 220, penetration or pressure from the outside, the PTC material included in the positive electrode safety function layer 213 may increase the internal temperature of the battery, causing the resistivity of the PTC material to increase due to the positive temperature coefficient of the PTC material. Since the short-circuit current is reduced due to the increase in the resistance of the positive electrode safety function layer 213, the risk of damage to the battery due to heat caused by the short-circuit current and a chain reaction in which the short-circuit current increases can be reduced.

[0074] Figure 4a and Figure 4b are cross-sectional views of batteries 200 a , 200 b according to various embodiments.

[0075] Figure 4c It shows Figure 4bThe wound component of the wound type battery 200b is unfolded.

[0076] Figure 4d A state in which a wound component of a wound type battery 200 b according to another embodiment is unfolded is shown.

[0077] Figure 4a is a diagram showing a stacked battery 200a (eg, Figure 1a Schematic diagram of a cross section of a battery 100a). Figure 4b to Figure 4d A wound battery 200b (eg, Figure 1b to Figure 1c A cross section of batteries 100b, 100c) and a state in which their components are unfolded.

[0078] Figure 4a The cross section is along Figure 1a The cross section taken by line A-A', Figure 4b is along Figure 1b The cross section taken by line BB', Figure 4c and Figure 4d is along Figure 1b The developed cross section taken along line BB'.

[0079] refer to Figure 4a , the positive electrode safety function layer 213 may be disposed in at least a portion of the inner positive electrode region 210b of the battery. Figure 4a , the positive electrode safety functional layer 213 of the stacked battery can be arranged in at least a portion of the inner positive electrode region 210b arranged between the outermost positive electrode regions 210a among the plurality of stacked positive electrodes 210. For example, the positive electrode safety functional layer 213 can be arranged in a region of the inner positive electrode region 210b that is relatively closer to the outermost positive electrode region 210a. In various embodiments, the thickness of the positive electrode safety functional layer 213 can be increased from the outermost positive electrode region 210a toward the inner side (in the range of 100 to 2000). Figure 4a direction) gradually decreases. Figure 4a An embodiment is shown in which the positive electrode safety functional layer 213 is not disposed in the innermost region 210c in the internal positive electrode region 210b, but this is not an example limiting the present disclosure, and it will be apparent that the technical ideas disclosed herein can also be applied to an embodiment in which the positive electrode safety functional layer 213 is arranged in the innermost region in the internal positive electrode region 210b and has the thinnest thickness.

[0080] refer to Figure 4b to Figure 4d, the positive electrode safety functional layer 213 of the wound battery 200b may extend from the outermost positive electrode region 210a to at least a portion of the inner positive electrode region 210b wound in a space positioned inward from the outermost positive electrode region 210a. For example, the positive electrode safety functional layer 213 may be positioned in an area of ​​the inner positive electrode region 210b that is relatively closer to the outermost positive electrode region 210a. In various embodiments, the thickness of the positive electrode safety functional layer 213 may be increased from the outermost positive electrode region 210a toward the inside (in the range of 100 to 2000a). Figure 4c The IN direction of the reference Figure 4c In various embodiments, the thickness of the positive electrode safety function layer 213 may be reduced in a stepwise manner. Figure 4d In various embodiments, the thickness of the positive electrode safety functional layer 213 may be continuously reduced.

[0081] Figures 4a to 4d An embodiment is shown in which the positive electrode safety functional layer 213 is not arranged in the innermost area of ​​the internal positive electrode region 210b, but this is an example that does not limit the present disclosure, and it will be apparent that the technical ideas disclosed in this document can also be applied to an embodiment in which the positive electrode safety functional layer 213 is arranged in the innermost area of ​​the internal positive electrode region 210b and has the thinnest thickness.

[0082] By placing the positive electrode safety functional layer 213 even in at least a portion of the internal positive electrode region 210b of the battery, the safety of the battery can be improved. In addition, the positive electrode safety functional layer 213 located in the internal positive electrode region 210b has a relatively thin thickness, minimizing the reduction in the energy density and / or power density of the battery, which may occur due to placing the positive electrode safety functional layer 213 in the internal positive electrode region 210b. The thickness of the positive electrode safety functional layer 213 in the internal positive electrode region 210b can be adjusted to optimize the safety of the battery and the energy density and / or power density of the battery.

[0083] Figure 5 is a cross-sectional view of a battery according to various embodiments.

[0084] refer to Figure 5, according to various embodiments of the battery (e.g., battery 100 or battery 200) may include a short circuit protection layer 240. The short circuit protection layer 240 may be arranged to correspond to the outer peripheral surface of the outermost positive electrode region 210a, to be spaced apart from the outermost positive electrode region 210a, and to be electrically connected to the negative electrode 220. For example, the short circuit protection layer 240 may be spaced apart from the outermost positive electrode region 210a by an insulating layer 241. The short circuit protection layer 240 may include a conductive material, for example, a metal material. The short circuit protection layer 240 may include a material that is the same or similar to the current collector of the opposite electrode to the electrode facing the short circuit protection layer 240. For example, the short circuit protection layer 240 facing the positive electrode 210 may include a material that is the same or similar to the current collector of the negative electrode 220 (e.g., copper (Cu)). In various embodiments, the negative electrode 220 current collector and the short circuit protection layer 240 may each include a tab configured to draw current to the outside, and the tabs may be connected by mutual welding so that the negative electrode 220 and the short circuit protection layer 240 can be electrically connected to each other.

[0085] When the electronic device is damaged by the outside (such as by penetration or pressure), a short-circuit current may flow in the region where the positive electrode / negative electrode active material is disposed of the positive electrode 210 and the negative electrode 220, thereby increasing the risk of fire. According to an embodiment, due to the short-circuit protection layer 240 included in the battery, when external damage occurs, a short circuit may first occur in the short-circuit protection layer 240, rather than in the region where the positive electrode / negative electrode active material is disposed. As a result, the potential difference in the region where the positive electrode / negative electrode active material is disposed can be reduced, thereby limiting the short-circuit current and reducing the risk of fire and other unsafe situations.

[0086] In various embodiments, the width (W1) of the short circuit protection layer 240 may be narrower than the width (W2) of the outermost positive electrode region 210a. In the case where the width (W1) of the short circuit protection layer 240 is wider than the outermost positive electrode region 210a, when an external impact is applied due to the battery falling, the short circuit protection layer 240 may be deformed. As a result, the short circuit protection layer 240 may contact the outermost positive electrode region 210a, resulting in the risk of short circuit. Therefore, the risk can be reduced by making the width (W1) of the short circuit protection layer 240 narrower than the width (W2) of the outermost positive electrode region 210a.

[0087] According to various embodiments of the present disclosure, a battery 200 may include a battery case 180 and an electrode assembly, the battery case 180 being configured to divide the inside and outside of the battery 200, the electrode assembly including at least one positive electrode 210 located inside the battery case 180, at least one negative electrode 220 located inside the battery case 180 to face the positive electrode 210, and at least one separator 230 disposed between the positive electrode 210 and the negative electrode 220.

[0088] The positive electrode 210 may include a positive electrode safety functional layer 213 located in a region including the outermost positive electrode region 210 a and closest to the inner surface of the battery case 180 among the regions of the positive electrode 210 .

[0089] In various embodiments, the battery 200 may be a wound type battery 200 b in which the electrode assemblies are wound in an overlapping manner, and the positive electrode 210 , the negative electrode 220 , and the separator 230 may be wound such that the outermost positive electrode region 210 a is positioned toward the outside of the battery 200 .

[0090] In various embodiments, the positive electrode safety functional layer 213 may extend from the outermost positive electrode region 210a in the positive electrode 210 to at least a portion of the internal positive electrode region 210b, where the internal positive electrode region 210b is a region wound in a space positioned toward the interior of the battery 200, and the positive electrode safety functional layer 213 may be configured in the positive electrode 210 such that the thickness of the positive electrode safety functional layer 213 disposed in the outermost positive electrode region 210a is thicker than the positive electrode safety functional layer 213 extending to the internal positive electrode region 210b.

[0091] In various embodiments, the thickness of the positive electrode safety functional layer 213 may decrease in a stepwise manner toward the inside of the battery 200 .

[0092] In various embodiments, the thickness of the positive electrode safety functional layer 213 may continuously decrease toward the inside of the battery 200 .

[0093] In various embodiments, the battery 200 may be a stacked battery 200a obtained by alternately stacking a plurality of positive electrodes 210, a plurality of negative electrodes 220, and a plurality of separators 230, and the outermost positive electrode region 210a may correspond to the positive electrodes 210 located at the uppermost and lowermost layers among the plurality of stacked positive electrodes 210.

[0094] In various embodiments, the positive electrode safety functional layer 213 may be further disposed in at least a portion of an internal positive electrode region 210b corresponding to the positive electrode 210 stacked between the outermost positive electrode regions 210a, and the positive electrode safety functional layer 213 may be configured such that, among the regions of the positive electrode 210, the thickness of the positive electrode safety functional layer 213 disposed in the outermost positive electrode region 210a is thicker than the thickness of the positive electrode safety functional layer 213 disposed in the internal positive electrode region 210b.

[0095] In various embodiments, the thickness of the positive electrode safety functional layer 213 may gradually decrease toward the inside of the battery 200 .

[0096] In various embodiments, the positive electrode 210 may include a positive electrode current collector 211 and a positive electrode active material 212 located on a surface of the positive electrode current collector 211.

[0097] The positive electrode safety functional layer 213 may be located between the positive electrode current collector 211 and the positive electrode active material 212 .

[0098] In various embodiments, the positive electrode 210 may include a positive electrode current collector 211 and a positive electrode active material 212 on a surface of the positive electrode current collector 211 , and a positive electrode safety function layer 213 may coat a surface of the positive electrode active material 212 .

[0099] In various embodiments, the positive electrode safety functional layer 213 may include a positive temperature coefficient (PTC) material.

[0100] In various embodiments, the PTC material may include a polymer composite material.

[0101] In various embodiments, the positive electrode safety functional layer 213 may include a phosphate-based olivine material.

[0102] In various embodiments, the battery 200 may include a short circuit protection layer 240, which is disposed inside the housing of the battery 200 to be spaced apart from the outermost positive electrode region 210a while surrounding at least a portion of the outer peripheral surface of the outermost positive electrode region 210a, the short circuit protection layer being electrically connected to the negative electrode 220 and having a conductive material.

[0103] In various embodiments, the width of the short protection layer 240 may be narrower than the width of the outermost positive electrode region 210 a .

[0104] In various embodiments, the battery 200 may further include a negative electrode safety functional layer 223 disposed in a region of the negative electrode 220 corresponding to a region of the positive electrode 210 where the positive electrode safety functional layer 213 is disposed.

[0105] According to various embodiments of the present disclosure, the battery 200 may include a case of the battery 200 configured to divide the inside and outside of the battery 200, at least one positive electrode 210 located inside the case of the battery 200, at least one negative electrode 220 located inside the case of the battery 200 to face the positive electrode 210, at least one separator 230 disposed between the positive electrode 210 and the negative electrode 220, and safety function layers 213, 223 disposed in at least one of the positive electrode 210 or the negative electrode 220. The thickness of the safety function layers 213, 223 may increase toward a position relatively closer to the outside of the battery 200.

[0106] In various embodiments, the safety functional layer 213 , 223 may be disposed in the positive electrode 210 , and may include a positive temperature coefficient (PTC) material.

[0107] In various embodiments, the PTC material may include a polymer composite material.

[0108] In various embodiments, the safety functional layer 213 , 223 may be disposed in the positive electrode 210 , and may include a phosphate-based olivine material.

[0109] The embodiments disclosed in this document disclosed in this specification and the drawings are only specific examples presented to easily illustrate the technical content according to the embodiments disclosed in this document and to help understand the embodiments disclosed in this document, and are not intended to limit the scope of the embodiments disclosed in this document. Therefore, the scope of the various embodiments disclosed in this document should be interpreted as including all changes or modifications derived from the technical ideas of the various embodiments disclosed in this document in addition to the embodiments disclosed here.

Claims

1. A battery comprising: A battery case configured to divide the inside and the outside of the battery; as well as an electrode assembly comprising at least one positive electrode located inside the battery case, at least one negative electrode located inside the battery case to face the positive electrode, and at least one separator disposed between the positive electrode and the negative electrode, The positive electrode includes a positive electrode safety functional layer, which is arranged in a region including an outermost positive electrode region and closest to an inner surface of the battery case among the regions of the positive electrode.

2. The battery according to claim 1, wherein The battery is configured as a wound type battery in which the electrode assembly is wound so that portions thereof overlap each other, wherein the positive electrode, the negative electrode and the separator are wound so that the outermost positive electrode region is positioned toward the outside of the battery, wherein, among the regions of the positive electrode, the positive electrode safety functional layer extends from the outermost positive electrode region to at least a portion of an inner positive electrode region, the inner positive electrode region being a region wound in a space positioned toward the interior of the battery, and Wherein, the positive electrode safety functional layer is configured so that among the regions of the positive electrode, the thickness of the positive electrode safety functional layer arranged in the outermost positive electrode region is thicker than the thickness of the positive electrode safety functional layer extending to the inner positive electrode region.

3. The battery according to claim 2, wherein The thickness of the positive electrode safety functional layer decreases in a stepwise manner toward the interior of the battery.

4. The battery according to claim 2, wherein The thickness of the positive electrode safety functional layer continuously decreases toward the interior of the battery.

5. The battery according to claim 1, wherein The battery is configured as a stacked type battery including the plurality of positive electrodes, the plurality of negative electrodes, and the plurality of separators alternately stacked on each other, and The outermost positive electrode region corresponds to the positive electrodes located at the uppermost layer and the lowermost layer among the plurality of stacked positive electrodes.

6. The battery according to claim 5, wherein The positive electrode safety functional layer is further provided in at least a portion of an inner positive electrode region corresponding to the positive electrode stacked between the outermost positive electrode regions, wherein the positive electrode safety functional layer is configured such that, among the regions of the positive electrode, the thickness of the positive electrode safety functional layer arranged in the outermost positive electrode region is thicker than the thickness of the positive electrode safety functional layer arranged in the inner positive electrode region, and Wherein, the thickness of the positive electrode safety functional layer gradually decreases toward the interior of the battery.

7. The battery according to claim 1, wherein The positive electrode includes a positive electrode current collector and a positive electrode active material located on a surface of the positive electrode current collector, and Wherein, the positive electrode safety functional layer is located between the positive electrode current collector and the positive electrode active material.

8. The battery according to claim 1, wherein The positive electrode safety functional layer includes a positive temperature coefficient (PTC) material.

9. The battery according to claim 8, wherein The PTC material includes a polymer composite material.

10. The battery according to claim 1, wherein The positive electrode safety functional layer includes a phosphate-based olivine material.

11. The battery according to claim 1, wherein The battery includes a short circuit protection layer, which is provided in the battery case to be spaced apart from the outermost positive electrode region while surrounding at least a portion of an outer peripheral surface of the outermost positive electrode region, the short circuit protection layer being electrically connected to the negative electrode and having a conductive material, and Wherein, the width of the short-circuit protection layer is narrower than the width of the outermost positive electrode region.

12. A battery comprising: A battery case configured to divide the inside and the outside of the battery; at least one positive electrode located inside the battery housing; at least one negative electrode located inside the battery case to face the positive electrode; at least one separator disposed between the positive electrode and the negative electrode; and a safety functional layer disposed in at least one of the positive electrode and the negative electrode, The thickness of the safety functional layer increases toward a position relatively closer to the outside of the battery.

13. The battery according to claim 12, wherein: The safety functional layer is disposed in the positive electrode and includes a positive temperature coefficient (PTC) material.

14. The battery according to claim 13, wherein The PTC material includes a polymer composite material.

15. The battery according to claim 12, wherein The safety functional layer is disposed in the positive electrode and includes a phosphate-based olivine material.

Images