Negative electrode for rechargeable battery and rechargeable battery including same

Abstract

A negative electrode for a rechargeable battery and a rechargeable battery including the same are provided. The negative electrode includes: a substrate having a strip shape, a width of the substrate in a first direction being relatively shorter than a length of the substrate in a second direction crossing the first direction; and an active material layer on the substrate and including an oriented portion and a non-oriented portion, the active material layer being arranged in the order of the non-oriented portion, the oriented portion including a lower layer and an upper layer stacked on the substrate, an orientation direction of the lower layer and an orientation direction of the upper layer being different from each other.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a negative electrode for a rechargeable battery and a rechargeable battery including the negative electrode. Background Art

[0002] As technology develops and demands for mobile devices increase, the use of rechargeable batteries as an energy source is increasing.

[0003] One type / kind of rechargeable battery is a cylindrical rechargeable battery. The cylindrical rechargeable battery may include an electrode assembly formed by disposing electrodes on two surfaces (e.g., opposite surfaces or sides) of a separator and winding the electrodes into a core shape. A center pin may be disposed in a hollow portion at the center of the electrode assembly, and the electrode assembly may be mounted into a housing. A cap assembly may close and seal an open side of the housing.

[0004] The electrode assembly in the shape of a core is formed by repeatedly winding around a center pin, and the curvature radius of the electrode assembly is different on the inner and outer surfaces of the electrode. To solve this problem, the active material layer can be formed by pattern coating. However, as the size of the battery increases, a stripe coating method that continuously forms the active material can be applied instead of pattern coating.

[0005] However, when the electrolyte is injected into the cylindrical electrode assembly, the mixture layer in the central portion of the electrode assembly may have reduced electrolyte impregnation compared to the electrode plates at the upper and lower portions of the electrode assembly. As a result, a strip in which the electrolyte does not wet (or contact) the electrode assembly may be formed in the central portion of the electrode assembly. In this way, lithium is precipitated into the area not wetted by the electrolyte, resulting in reduced battery performance, reduced life of the electrode plates, and kinetic degradation.

[0006] In order to achieve a relatively high capacity, the thickness of the mixture layer formed on the electrode plate can be further increased and can become thicker, causing the non-wetting phenomenon of the electrolyte to become more serious, and in the case of a wound or wound-type electrode assembly, the undesirable non-wetting phenomenon may further increase toward the center of the electrode assembly.

[0007] The above information disclosed in this Background section is only for enhancement of understanding of the background technology of the disclosure and therefore it may contain information that does not constitute prior art. Summary of the invention

[0008] Aspects of embodiments of the present disclosure relate to a relatively high-capacity negative electrode for a rechargeable battery and a rechargeable battery including the negative electrode, wherein a non-wetting area is not generated, does not increase, and / or even decreases even if the thickness of an active material layer increases.

[0009] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosed presented embodiments.

[0010] According to one or more embodiments of the present disclosure, a negative electrode for a rechargeable battery includes: a substrate having a strip shape, wherein a width of the substrate in a first direction is relatively shorter than a length of the substrate in a second direction intersecting the first direction; and an active material layer on the substrate and including an oriented portion and a non-oriented portion, the active material layer being arranged in the first direction in the order of the non-oriented portion, the oriented portion, and the non-oriented portion, wherein the oriented portion includes a lower layer and an upper layer stacked on the substrate, and the orientation direction of the lower layer and the orientation direction of the upper layer are different from each other.

[0011] In one or more embodiments, the upper layer may include active material particles oriented at an angle (e.g., a set or predetermined angle) relative to the surface of the substrate (e.g., in a cross-sectional view), and the lower layer may include active material particles arranged in a direction parallel to the surface of the substrate (e.g., in a cross-sectional view).

[0012] In one or more embodiments, the upper layer I 002 / I 110 The value can be smaller than the I 002 / I 110 value.

[0013] In one or more embodiments, the active material particles of the upper layer may have an angle of about 10° to about 80° with respect to the surface of the substrate.

[0014] In one or more embodiments, the orientation portion of I 002 / I 110 The value can be smaller than the I of the non-oriented part 002 / I 110 value.

[0015] In one or more embodiments, the upper layer and the lower layer may be made of different active materials.

[0016] In one or more embodiments, the width of the alignment portion in the first direction may be about 10% to about 90% of the width of the active material layer in the first direction.

[0017] In one or more embodiments, the thickness of the lower layer may be about 10% to about 90% of the total thickness of the active material layer, and the thickness of the upper layer may be about 10% to about 90% of the total thickness of the active material layer.

[0018] According to one or more embodiments of the present disclosure, a rechargeable battery includes: a wound or wound-type (e.g., an electrode core) assembly, including the negative electrode, a separator, and a positive electrode; a shell, which accommodates the wound or wound-type electrode assembly; a cover plate, which is installed in an opening of the shell to seal the interior of the shell; and an electrolyte, which is accommodated in the shell together with the wound or wound-type electrode assembly, wherein the first direction is the direction in which the electrolyte is injected into the shell.

[0019] In one or more embodiments, the wound type or wound-like electrode assembly may be a cylindrical electrode assembly.

[0020] According to one or more embodiments, if (for example, when) the alignment portion is arranged in a portion where the non-wetting region occurs, the electrolyte can move smoothly and the non-wetting region can be minimized or reduced. Therefore, by increasing the thickness of the active material layer, a negative electrode that minimizes or reduces the non-wetting region while maintaining a relatively high capacity can be provided, and a rechargeable battery including the negative electrode can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a perspective cross-sectional view of a rechargeable battery according to one or more embodiments of the present disclosure.

[0022] Figure 2 is a plan view of an expanded negative electrode according to one or more embodiments of the present disclosure.

[0023] Figure 3 According to one or more embodiments of the present disclosure, Figure 2 A cross-sectional view taken along line III-III.

[0024] Figure 4 is a schematic diagram for describing the orientation of a negative active material according to one or more embodiments of the present disclosure.

[0025] Figure 5 is an image measuring the impregnation properties of a cylindrical electrode assembly according to one or more embodiments of the present disclosure.

[0026] Figure 6 is an image measuring the impregnation properties of a cylindrical electrode assembly according to comparable technology.

[0027] Figure 7 is a diagram for describing movement of an electrolyte according to one or more embodiments of the present disclosure.

[0028] Figure 8 is a graph showing dQ / dV according to relative voltage in a comparative example and an example. DETAILED DESCRIPTION

[0029] The present disclosure can be modified in many alternative forms, and therefore specific embodiments will be shown in the drawings and described in more detail. However, it should be understood that this is not intended to limit the present disclosure to the particular form disclosed, but is intended to cover all modifications, equivalents and substitutes falling within the spirit and scope of the present disclosure.

[0030] Hereinafter, embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. However, the present disclosure may be implemented in various different forms and should not be construed as being limited to the embodiments shown herein. On the contrary, these embodiments are provided as examples so that the present disclosure will be thorough and complete, and will fully convey the aspects and features of the present disclosure to those skilled in the art. Therefore, processes, elements, and techniques that are not necessary for a person of ordinary skill in the art to fully understand the aspects and features of the present disclosure may not be described.

[0031] For convenience of description, the size and thickness of each component shown in the drawings may be exaggerated or reduced, and the present disclosure is not necessarily limited to the shown examples.

[0032] In the drawings, the thickness of layers, films, panels, regions, etc. may be exaggerated for clarity. In addition, in the drawings, the thickness of some layers and regions may be exaggerated for convenience of explanation.

[0033] Unless otherwise noted, like reference numerals denote like elements throughout the accompanying drawings and written description, and thus, repeated description thereof may not be provided.

[0034] It will be understood that, although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the spirit and scope of the present disclosure, the first element, first component, first region, first layer or first part described below may be referred to as the second element, second component, second region, second layer or second part.

[0035] For ease of explanation, spatially relative terms such as "on", "below", "lower (lower part)", "below", "above", "upper (upper part)", etc. may be used herein to describe the relationship of one element or feature to another element or features as shown in the figure. It will be understood that, in addition to the orientation depicted in the figure, the spatially relative terms are intended to cover different orientations of the device in use or operation. For example, if the device in the figure is turned over, the elements described as "below" or "below" or "below" other elements or features will then be oriented to be "above" the other elements or features. Therefore, the example terms "below" and "below" can cover both the above and below orientations. The device can be oriented otherwise (e.g., rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0036] It will be understood that when an element such as a region, layer, film, zone or portion is referred to as being "on," "connected to" or "coupled to" another element, it can be directly on, directly connected to or directly coupled to the other element, or one or more intervening elements may be present. Additionally, it will be understood that when an element is referred to as being "between" two elements, it can be the only element between the two elements, or one or more intervening elements may also be present.

[0037] It will also be understood that when the terms "comprises," "including," and "having" and variations thereof are used in this specification, they indicate the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0038] As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0039] Unless otherwise apparent from the disclosure, expressions such as “at least one of…,” “a plurality of…,” “one of…,” and other prepositional phrases, when followed (preceded) by a list of elements, should be understood to include the disjunct if written as a conjunction list, and vice versa. For example, the expressions “at least one of a, b, or c,” “at least one of a, b, and / or c,” “one selected from the group consisting of a, b, and c,” “at least one selected from a, b, and c,” “at least one among a, b, and c,” “one among a, b, and c,” “at least one from a to c” mean only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof.

[0040] Figure 1 is a perspective cross-sectional view of a rechargeable battery according to one or more embodiments of the present disclosure.

[0041] like Figure 1 As shown in , a rechargeable battery 1000 according to one or more embodiments of the present disclosure includes an electrode assembly 10, a shell 20 in which the electrode assembly 10 is built, a cover assembly 30 coupled to an opening of the shell 20 via a gasket and electrically connected to the electrode assembly 10, an insulating plate 50 disposed between the cover assembly 30 and the electrode assembly 10, and a center pin 60 arranged at the center of the electrode assembly 10.

[0042] The electrode assembly 10 includes a first electrode 11, a separator 12, and a second electrode 13, which are sequentially stacked. The electrode assembly 10 may be a cylindrical core in which the first electrode 11, the separator 12, and the second electrode 13 are stacked and then wound around a center pin 60.

[0043] The first electrode 11 is formed of a thin conductive metal plate and includes a substrate serving as a current collector and an active material layer. For example, the substrate of the first electrode 11 may be aluminum (Al).

[0044] The first electrode 11 includes a substrate, an electrode active portion 11a, and a first electrode uncoated portion 11b. In the electrode active portion 11a, an active material layer is formed on both surfaces (e.g., opposite surfaces or opposite sides) of the substrate, and the first electrode uncoated portion 11b is a region where the substrate is exposed due to the absence of an active material layer. The first electrode uncoated portion 11b may be formed along the edge of the active material layer in the winding direction, but the present disclosure is not limited thereto. The first electrode uncoated portion 11b may be formed only at the end of the winding direction by removing the portion formed along the edge in the winding direction through a cutting process (see, for example, FIG. 1 ). Figure 2 ).

[0045] As the positive active material of the first electrode 11, a compound capable of reversibly inserting and extracting lithium (lithiated insert compound) can be used. For example, a composite oxide including lithium and one or more types (species) of metals selected from cobalt, manganese, nickel and / or (e.g., any suitable) combination thereof can be used. The content (e.g., amount) of the positive active material can be about 90 wt % to about 98 wt % based on the total weight of the positive active material layer.

[0046] The positive active material layer may further include a binder and a conductive material. In such an embodiment, the binder and the conductive material may each be present in an amount (eg, amount) of about 1 wt % to about 5 wt % based on the total weight of the positive active material layer.

[0047] The binder is used to properly adhere the positive active material particles to each other, and also to properly adhere the positive active material to the substrate as the current collector. Representative examples of binders may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene butadiene rubber, acrylated styrene butadiene rubber, epoxy resin, nylon, etc., but the present disclosure is not limited thereto. The conductive material is used to impart conductivity to the electrode, and any electronic conductive material can be used in the constructed battery as long as it does not cause chemical changes.

[0048] The second electrode 13 is formed of a thin conductive metal plate and includes a substrate serving as a current collector and an active material layer. For example, the substrate of the second electrode 13 may be copper (Cu).

[0049] The second electrode 13 includes a substrate, a second electrode active portion 13a, and a second electrode uncoated portion 13b, in which an active material layer is formed on both surfaces (e.g., opposite surfaces or opposite sides) of the substrate, and the second electrode uncoated portion 13b is a region where the substrate is exposed due to the absence of an active material layer. The second electrode uncoated portion 13b may be formed on at least one edge of the active material layer, and may be formed along the edge of the active material layer in the winding direction, but the present disclosure is not limited thereto, and the second electrode uncoated portion 13b may be formed only at the end of the winding direction by removing a portion formed along the edge in the winding direction through a cutting process.

[0050] The negative electrode active material of the second electrode 13 may be a carbon-based active material. The carbon-based negative electrode active material may be artificial graphite and / or a (for example, any suitable) mixture of artificial graphite and natural graphite. When using artificial graphite or a crystalline carbon-based material as a mixture of artificial graphite and natural graphite as the negative electrode active material, compared with the case of using an amorphous carbon-based active material (for example, when using an amorphous carbon-based active material), the crystalline characteristics of the particles are further enhanced, so it is possible to expect further improvement in the orientation characteristics of the carbon material in the electrode plate with respect to the external magnetic flux. The shape of the artificial graphite or natural graphite may be amorphous, plate-shaped (for example, in the form of a plate), flake-shaped (for example, in the form of a flake), spherical-shaped, fiber-shaped, and / or a (for example, any suitable) combination thereof, and may be any shape. In one or more embodiments, if (for example, when) a mixture of artificial graphite and natural graphite is used, the mixing ratio may be a weight (wt%) ratio of about 70:30 to about 95:5.

[0051] In one or more embodiments, the negative electrode active material may further include at least one of a Si-based negative electrode active material, a Sn-based negative electrode active material, or a LiMO x (M = metal) - based negative electrode active material. When the negative electrode active material further includes these negative electrode active materials, that is, if (for example, when) the negative electrode active material includes a carbon-based negative electrode active material as the first negative electrode active material and one of the above negative electrode active materials (for example, a Si-based negative electrode active material, a Sn-based negative electrode active material, or a LiMO x (M = metal) - based negative electrode active material) as the second negative electrode active material, the mixing ratio of the first negative electrode active material and the second negative electrode active material may be a weight ratio of about 50:50 to about 99:1.

[0052] LiMO x (M = metal) - based negative electrode active material may be lithium vanadium oxide.

[0053] The Si-based negative electrode active material may include Si, Si - C composite, SiO x (0 < x ≤ 2) and Si - Q alloy (Q is an element selected from the group consisting of alkali metals, alkaline earth metals, group 13 elements, group 14 elements, group 15 elements, group 16 elements, transition metals, rare earth elements, and / or a (for example, any suitable) combination thereof, but not Si), and the Sn-based negative electrode active material may include Sn, SnO x(0 < x ≤ 2, including SnO2) and / or Sn-R alloy (R is an element selected from the group consisting of alkali metals, alkaline earth metals, group 13 elements, group 14 elements, group 15 elements, group 16 elements, transition metals, rare earth elements, and / or any suitable combination thereof, but not Sn). Additionally, a mixture of at least one of them and SiO2 can also be used. As elements Q and R, elements selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, and / or any suitable combination thereof can be used.

[0054] Based on the total weight of the negative electrode active material layer, the content (e.g., amount) of the negative electrode active material in the negative electrode active material layer can be about 95 wt% to about 99 wt%.

[0055] The negative electrode active material layer can further include a binder and optionally can also include a conductive material. Based on the total weight of the negative electrode active material layer, the content (e.g., amount) of the binder in the negative electrode active material layer can be 1 wt% to 5 wt%. In one or more embodiments, if (e.g., when) a conductive material is also included, the negative electrode active material layer can contain about 90 wt% to about 98 wt% of the negative electrode active material, about 1 wt% to about 5 wt% of the binder, and about 1 wt% to about 5 wt% of the conductive material.

[0056] The binder properly and well bonds the negative electrode active material particles to each other and also properly and well bonds the negative electrode active material to the negative electrode substrate. As the binder, a non-aqueous binder, an aqueous binder, and / or any suitable combination thereof can be used.

[0057] Examples of non-aqueous binders can include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, and polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, and / or any suitable combination thereof.

[0058] Examples of aqueous binders may include styrene-butadiene rubber, acrylated styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber, acryl rubber, butyl rubber, ethylene propylene copolymer, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, acryl resin, phenolic resin, epoxy resin, polyvinyl alcohol, acrylic resin and / or (e.g., any suitable) combination thereof.

[0059] When an aqueous binder is used as a negative electrode binder, a cellulose compound capable of imparting viscosity may be further included as a thickener. As a cellulose compound, one or more types (types) of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose and their alkali metal salts may be used. Na, K or Li may be used as an alkali metal. Based on 100 parts by weight of the negative electrode active material, the amount of the thickener used may be from about 0.1 parts by weight to about 3 parts by weight.

[0060] The conductive material is used to impart conductivity to the electrode, and any electronically conductive material can be used in the constructed battery as long as it does not cause chemical changes. Examples of the conductive material may include: carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, and / or carbon fiber; metal materials such as metal powder (such as copper, nickel, aluminum, and / or silver) and / or metal fibers; conductive polymers such as polyphenylene derivatives; and / or conductive materials containing (e.g., any suitable) mixture thereof.

[0061] In one or more embodiments, the Brunauer-Emmett-Teller (BET) specific surface area of ​​the negative electrode active material layer may be less than about 3.0 m 2 / g, and can also be about 0.6m 2 / g to about 1.2m 2 / g. When the BET specific surface area of ​​the negative electrode active material layer is less than about 3.0 m 2 / g, the electrochemical life characteristics of the battery can be improved.

[0062] The BET measurement is performed by a nitrogen adsorption method of charging and discharging a lithium secondary battery including a negative electrode, cutting the negative electrode obtained by disassembling a fully discharged battery into a certain size, and placing the cut negative electrode in a BET sample holder.

[0063] The negative electrode may have a 2 To about 65mg / cm 2 The cross-sectional load level (L / L).

[0064] In one or more embodiments, the negative active material layer according to one or more embodiments of the present disclosure includes an alignment portion and a non-alignment portion.

[0065] Figure 2 is a plan view of an expanded negative electrode according to one or more embodiments of the present disclosure. Figure 3 According to one or more embodiments of the present disclosure, Figure 2 A cross-sectional view taken along line III-III.

[0066] Reference Figure 2 and Figure 3 The negative electrode as the second electrode 13 includes a substrate 2 and an active material layer 3 formed on the substrate 2. The substrate 2 may have a strip shape having a width in a first direction relatively shorter than a length in a second direction intersecting the first direction.

[0067] The active material layer 3 includes an alignment portion LA and a non-alignment portion LB, and the alignment portion LA may include a lower layer 3a on the substrate 2 and an upper layer 3b on the lower layer 3a. The alignment portion LA may be about 10% to about 90% based on the total width D of the active material layer 3.

[0068] Figure 4 is a schematic diagram for describing the orientation of a negative active material according to one or more embodiments of the present disclosure.

[0069] The alignment portion LA may be aligned in such a manner that the active material particles have a constant angle with respect to a surface (eg, upper surface) of the substrate. Figure 4 , after applying the negative electrode substrate while moving the negative electrode substrate, the active material particles are oriented at a constant angle relative to a surface (eg, upper surface) of the substrate using a magnetic flux.

[0070] The magnetic flux caused by the magnet is formed in the direction of the normal line of the negative electrode substrate (e.g., perpendicular to the negative electrode substrate), but the direction in which the magnetic field is formed depends on the coating speed (e.g., the moving speed of the negative electrode substrate) and is formed at a constant angle as a vector function, so the negative electrode active material particles included in the negative electrode active material composition can have a shape that is upright (i.e., oriented) at a certain angle relative to the surface of the negative electrode substrate.

[0071] The orientation angle and orientation direction of the orientation portion LA can be adjusted by the intensity of the magnetic flux applied to the active material layer, the time of exposure to the magnetic flux, and the viscosity of the negative active material composition.

[0072] Since a separate alignment process is not performed in the non-alignment portion LB, active material particles having various directions and angles may be mixed. Therefore, the non-alignment portion LB may be diffusely aligned when compared with the alignment portion LA.

[0073] Compared with the active material layer in the oriented portion LA, the movement of Li ions in the active material layer in the non-oriented portion LB is relatively unsmooth, and therefore the DC internal resistance is relatively high in the non-oriented portion LB.

[0074] During XRD measurement of the negative electrode using CuKα rays, when the ratio of the peak intensity of the (002) plane of the non-oriented portion LB to the peak intensity of the (110) plane is set to 1, the ratio of the peak intensity of the (002) plane of the oriented portion LA to the peak intensity of the (110) plane may be less than 1. For example, the I 002 / I 110 It may be about 200 or more, and the I of the oriented portion LA 002 / I 110 It can be less than about 200.

[0075] In one or more embodiments, in order to increase the impregnation of the active material layer while the oriented portion LA maintains adhesion to the substrate 2, the upper layer 3b may be oriented while the lower layer 3a remains non-oriented. Therefore, the lower layer 3a may be formed from 10% to 90% based on the total thickness of the active material layer, and the upper layer 3b may be formed from 10% to 90% based on the total thickness of the active material layer.

[0076] The active material particles of the upper layer 3 b may be oriented at an angle of about 10° to about 80° based on (relative to) the surface (eg, upper surface) of the substrate 2, and if (eg, when) the peak intensity of the lower layer 3 a is greater than I 002 / I 110 is 1, the peak intensity ratio of the upper layer 3 b may be less than 1. For example, if (for example, when) the peak intensity ratio of the lower layer 3 a is about 200, the peak intensity ratio of the upper layer 3 b may be less than about 200.

[0077] Return to reference Figure 2 and Figure 3 In order to increase the orientation, the orientation portion LA may be made of a material different from that of the non-orientation portion LB, and the lower layer 3a and the upper layer 3b of the orientation portion LA may also be made of different materials.

[0078] The lower layer 3a and the upper layer 3b of the alignment portion LA have been described as being made of the same material, but the present disclosure is not limited thereto, and the lower layer and the upper layer may be made of different materials.

[0079] The orientation degree or orientation angle of the active material particles in the lower layer 3a and the upper layer 3b may be different from each other. The upper layer 3b may be oriented in the normal direction of the substrate (e.g., perpendicular to the substrate) and oriented at a larger angle than the lower layer 3a relative to the surface (e.g., upper surface) of the substrate 2, and the lower layer 3a may be oriented at a smaller angle than the upper layer 3b relative to the surface (e.g., upper surface) of the substrate 2, or may not be oriented at a specific angle.

[0080] Therefore, when in e.g. Figure 3 When viewed in the cross-sectional view shown in , the upper layer 3b may further include more active material particles oriented in the normal direction (e.g., perpendicular to the surface (e.g., upper surface) of the substrate 2 compared to the lower layer 3a, and the lower layer 3a may further include more active material particles oriented in the direction parallel to the surface (e.g., upper surface) of the substrate compared to the upper layer 3b. In one or more embodiments, the lower layer 3a may be diffusely oriented like the non-oriented portion LB.

[0081] The active material particles of the negative electrode have an elongated shape in approximately one direction, and the oriented active material particles have the major axis of the active material particles tilted relative to the substrate. Therefore, the end of the active material particle in the major axis direction may contact the substrate, and the adhesion to the substrate 2 may be relatively lower than the adhesion to the substrate 2 of the non-oriented portion LB whose major axis is parallel to the substrate.

[0082] Therefore, in one or more embodiments of the present disclosure, the lower layer 3a is relatively non-oriented compared to the upper layer 3b, thereby increasing adhesion to the substrate.

[0083] In one or more embodiments, the upper layer 3b may be oriented to increase the mobility of the electrolyte and minimize or reduce the occurrence of non-wetting areas.

[0084] In this way, in one or more embodiments of the present disclosure, the occurrence of non-wetting areas in a wound type or wound-type electrode assembly may be minimized or reduced by arranging oriented portions and non-oriented portions having different degrees of orientation according to positions.

[0085] Return to reference Figure 1 The separator 12 is arranged between the first electrode 11 and the second electrode 13 and insulates them. A multilayer film of two or more layers of polyethylene, polypropylene, polyvinylidene fluoride or their (for example, any suitable) combination can be used as the separator 12, and a mixed multilayer such as a polyethylene / polypropylene double-layer separator, a polyethylene / polypropylene / polyethylene three-layer separator, or a polypropylene / polyethylene / polypropylene three-layer separator can be used.

[0086] In the core state, the first electrode current collecting plate 11 d is connected to the first electrode non-coating portion 11 b of the electrode assembly 10 , and the second electrode current collecting plate 13 d is connected to the second electrode non-coating portion 13 b of the electrode assembly 10 .

[0087] The second electrode current collecting plate 13 d is in contact with the case 20 , but the first electrode current collecting plate 11 d is formed to be narrower than the second electrode current collecting plate 13 d and thus is formed not to be in contact with the case 20 .

[0088] The first electrode uncoated portion 11b is bent toward the center pin 60 as the center of the electrode assembly 10, and adjacent first electrode uncoated portions 11b may overlap and be electrically connected to each other. The first electrode uncoated portion 11b may be electrically connected to the first electrode current collecting plate 11d in a stacked state.

[0089] The first electrode uncoated portion 11 b includes one surface electrically connected by contacting the first electrode current collecting plate 11 d and another surface facing the end of the second electrode 13 and separated and / or isolated (eg, spaced or separated) from the end of the second electrode 13 .

[0090] The lead tab 37 is electrically connected to the first electrode current collecting plate 11 d .

[0091] One end of the lead tab 37 may be connected to the first electrode uncoated portion by welding to the first electrode current collecting plate 11d, and the other end of the lead tab 37 may be electrically connected to the cap assembly 30. The lead tab 37 may be bent so that one surface faces the cap assembly 30 to increase a contact area with the cap assembly 30.

[0092] An insulating plate 50 having an opening exposing the center pin 60 is located on the first electrode current collecting plate 11 d .

[0093] The insulating plate 50 is formed larger than the first electrode current collecting plate 11d so that the insulating plate 50 can contact the inner surface of the case 20. If (for example, when) the insulating plate 50 is formed larger than the first electrode current collecting plate 11d, a constant gap is formed between the first electrode current collecting plate 11d and the case 20 due to the width of the insulating plate 50 protruding to the outside of the first electrode current collecting plate 11d. The gap between the first electrode current collecting plate 11d and the case 20 can prevent or reduce the first electrode current collecting plate 11d from contacting and short-circuiting the case 20.

[0094] The lead tab 37 may contact and be connected to the first auxiliary plate 34 of the cap assembly 30 through the opening 51 of the insulation plate 50 , which will be described in more detail later.

[0095] Since the electrode assembly 10 is wound around the center pin 60 , the center pin 60 is disposed at the center of the electrode assembly 10 , and may be disposed parallel to a direction in which the electrode assembly 10 is inserted into the case 20 .

[0096] The center pin 60 is used to minimize or reduce deformation and / or maintain a shape close to the shape before deformation if (for example, when) receiving the entire compression load or local impact load acting from the outside of the rechargeable battery, and may be a hollow circular tube. In one or more embodiments, the center pin 60 may be used as a movement channel for internally generated gas. If necessary or desired, the center pin 60 may not be provided.

[0097] The center pin 60 may be formed of a material having a certain rigidity (for example, a conductive metal such as steel, steel alloy, aluminum, aluminum alloy, etc.) to minimize deformation when exposed to external impact. In this way, since the center pin 60 is conductive, both ends of the center pin 60 are installed to maintain an electrical insulation state between the first electrode current collecting plate 11d and the second electrode current collecting plate 13d.

[0098] For example, the insulating pad 52 is arranged between the lower end of the center pin 60 and the corresponding second electrode current collecting plate 13d. The upper end of the center pin 60 passes through the through hole formed in the center of the first electrode current collecting plate 11d in an insulated state and is supported on the insulating plate 50. In one or more embodiments, the upper end of the center pin 60 can be separated and / or separated (e.g., spaced or separated) from the through hole of the first electrode current collecting plate 11d, and the insulating member can be placed between the upper end of the center pin 60 and the through hole of the first electrode current collecting plate 11d. Therefore, the movement of the center pin 60 in the longitudinal direction of the center pin 60 is restricted, and the center pin 60 can be maintained at the center of the electrode assembly 10 in a stable state.

[0099] One side of the case 20 is opened so that the electrode assembly 10 can be inserted together with the electrolyte, and the case 20 may be formed to have substantially the same shape as that of the core-shaped electrode assembly 10 .

[0100] For example, the housing 20 may include a circular bottom and a cylindrical side extending upward from the bottom by a certain length. During the assembly process of the rechargeable battery, the upper portion of the cylindrical housing may be open. Therefore, during the assembly process of the rechargeable battery, the electrode assembly may be inserted into the cylindrical housing, and then the electrolyte may be injected into the cylindrical housing.

[0101] The electrolyte allows lithium ions generated by the electrochemical reaction to move between the first electrode and the second electrode inside the battery. The electrolyte may be composed of an organic solvent such as ethylene carbonate (EC), propylene carbonate (PC), diethyl carbonate (DEC) and / or ethyl methyl carbonate (EMC) and a lithium salt such as LiPF6 and / or LiBF4. The electrolyte may be in a liquid phase, a solid phase or a gel phase.

[0102] The housing 20 is connected to the second electrode current collecting plate 13d of the electrode assembly and can be used as a second electrode terminal of the rechargeable battery. Therefore, the housing 20 can be made of a conductive metal (e.g., an electronic conductor metal) such as aluminum, an aluminum alloy, or nickel-plated steel. In one or more embodiments, similar to the first electrode current collecting plate 11d, a separate electrode tab can be attached and connected to the second electrode current collecting plate 13d.

[0103] The cap assembly 30 is positioned in the opening of the case 20 with the gasket 40 interposed therebetween. The gasket 40 insulates the case 20 and the cap assembly 30, and seals the interior of the case 20 accommodating the electrode assembly 10 and the electrolyte.

[0104] The cap assembly 30 includes a cap plate 31 , a positive temperature coefficient element 35 , a gas exhaust plate 32 , an insulating member 33 , a first auxiliary plate 34 , and a second auxiliary plate 38 .

[0105] The first auxiliary board 34 may be electrically connected to the lead tab 37 , and may be bonded to the lead tab 37 by welding.

[0106] The second auxiliary plate 38 may be stacked on and electrically connected to the first auxiliary plate 34, and may be welded to the first auxiliary plate 34. The second auxiliary plate 38 is located at the center of the electrode assembly 10 corresponding to the center pin 60, and has a through hole that exposes the first auxiliary plate 34.

[0107] The exhaust plate 32 is located on the second auxiliary plate 38 with the insulating member 33 interposed therebetween. An edge of the exhaust plate 32 may be inserted into the gasket 40 and coupled to the housing 20.

[0108] The exhaust plate 32 includes an exhaust port 32a located in a portion corresponding to the center pin 60. The exhaust port 32a protrudes from the exhaust plate 32 toward the electrode assembly 10, and contacts and is electrically connected to the first auxiliary plate 34 through the through hole. The exhaust plate 32 may have a notch 32b around the exhaust port 32a, the notch 32b guiding damage to the exhaust port 32a.

[0109] The exhaust port 32a may be destroyed under a preset pressure condition, thereby releasing the internal gas to the outside and preventing electrical connection with the first auxiliary board 34. For example, if (e.g., when) the internal pressure of the housing 20 increases due to the generation of gas, the recess 32b is destroyed in advance, and the gas is discharged to the outside through the exhaust port 31d (to be described in more detail later), thereby preventing or substantially preventing the rechargeable battery from swelling or exploding.

[0110] In one or more embodiments, if (for example, when) the abnormal reaction continues and the exhaust port 32a is destroyed, the electrical connection between the exhaust plate 32 and the first auxiliary plate 34 is disconnected. Therefore, the electrical connection between the cover plate 31 electrically connected to the exhaust plate 32 and the first auxiliary plate 34 is disconnected, so that no current flows.

[0111] The cap plate 31 includes a center plate 31a corresponding to the center pin 60 as the center of the electrode assembly 10, a plurality of branch portions 31b extending from the center plate 31a toward the gasket 40, and a coupling plate 31c connected to one end of the branch portions 31b and inserted into and coupled to the gasket 40. A discharge port 31d that opens to the outside and discharges internal gas is formed between adjacent branch portions 31b.

[0112] The branch portion 31b is connected to the central plate 31a while being bent from the coupling plate 31c, so that the center of the cap plate 31 can protrude to the outside of the housing 20. The cap plate 31 is electrically connected to the first electrode current collecting plate 11d through the exhaust plate 32, the second auxiliary plate 38, the first auxiliary plate 34, and the lead tab 37, and thus can be used as a first electrode terminal of a rechargeable battery. Therefore, if (for example, when) the center of the cap plate 31 is formed to protrude to the outside of the housing 20, terminal connection with an external device can be facilitated.

[0113] In one or more embodiments, the positive temperature coefficient element 35 may be formed along an edge of the cover plate 31 and may be inserted into and coupled to the gasket 40 while being stacked between the coupling plate 31 c of the cover plate 31 and an edge of the exhaust plate 32 .

[0114] The positive temperature coefficient element 35 is installed between the cap plate 31 and the exhaust plate 32 , and may adjust the flow of current between the cap plate 31 and the exhaust plate 32 according to the internal temperature of the rechargeable battery.

[0115] If (for example, when) the internal temperature is within a preset range, the positive temperature coefficient element 35 acts as a conductor (electronic conductor) to make an electrical connection between the cap plate 31 and the exhaust plate 32. However, if (for example, when) the internal temperature exceeds the preset temperature, the positive temperature coefficient element 35 has a resistance (electronic insulator) that increases to infinity. Therefore, the positive temperature coefficient element 35 can block or reduce the flow of charging current or discharging current between the cap plate 31 and the exhaust plate 32.

[0116] While the electrode assembly 10 is inserted into the case 20 , the cap assembly 30 is inserted into the gasket 40 in the form of the exhaust plate 32 , the positive temperature coefficient element 35 and the cap plate 31 stacked on the edge of the cap assembly 30 and then inserted into the opening of the case 20 .

[0117] Then, the cap assembly 30 is fixed to the opening of the case 20 by a crimping process. In this case, a crimping portion 21 and a crimping portion 22 may be formed on the side adjacent to the opening of the case 20. The crimping portion 21 may be formed by a crimping process. The crimping portion 21 has a structure that is recessed from the upper side of the case 20 toward the radial center of the case 20 while the electrode assembly 10 is accommodated in the case 20, and prevents the electrode assembly 10 from moving up and down.

[0118] The crimping portion 22 is connected to the bead portion 21 in a structure relatively protruding from the bead portion 21 in the radial direction, and holds the outer peripheral surface (edge) of the cover assembly 30 via the gasket 40, wherein the upper and lower surfaces of the cover assembly 30 are connected to the outer peripheral surface (edge).

[0119] Figure 5 is an image measuring the impregnation properties of a cylindrical electrode assembly according to one or more embodiments of the present disclosure. Figure 6 is an image measuring the impregnation properties of a cylindrical electrode assembly according to comparable technology.

[0120] exist Figure 5 and Figure 6 As the color becomes darker, the electrolyte is not delivered to a higher degree. Figure 5 and Figure 6 middle, Figure 5 The area of ​​the non-wetting region of the electrode assembly according to one or more embodiments of the present disclosure is less than Figure 6 The area of ​​the non-wetted region of an electrode assembly according to comparable technology.

[0121] Therefore, according to one or more embodiments of the present disclosure, by disposing the orientation portion between the non-orientation portions so that the orientation portion is located at the center of the cylindrical electrode assembly, the occurrence of a non-wetting area in the center of a wound or wound-type electrode assembly can be minimized or reduced.

[0122] Reference Figure 7 If (for example, when) an electrolyte is injected into the shell 20 accommodating the cylindrical electrode assembly 10, the electrolyte flows from both ends of the center pin 60 toward the center of the center pin 60, and the electrolyte moves to the active material layer of the second electrode (negative electrode) 13 disposed adjacently while flowing through the center pin 60.

[0123] When the electrolyte is injected in the first direction D1 parallel to the center pin 60 , the electrolyte branches to a second direction D2 orthogonal to (eg, perpendicular to) the first direction D1 while moving in the first direction D1 .

[0124] In this case, in one or more embodiments of the present disclosure, the movement distance of the electrolyte is relatively long, and the active material particles in the central portion of the electrode assembly that are not easily injected with the electrolyte are arranged in a direction orthogonal (e.g., vertical) to the substrate, so that the movement of the electrolyte along the second direction D2 can be carried out smoothly.

[0125] Table 1 shows data of measuring the adhesive forces according to Comparative Examples 1 and 2 and Examples.

[0126] Table 1

[0127] Comparative Example 1 is a battery that is not oriented at all because no alignment treatment is performed, Comparative Example 2 is a battery that is completely oriented, and Comparative Example 1 is a battery that is oriented in the center portion and not oriented at the edge.

[0128] Referring to Table 1, the adhesion of the completely non-oriented comparative example 1 is 1.66 and 1.36, the adhesion of the completely oriented comparative example 2 is 1.21 and 1.29, but the adhesion of the example in which the center part is oriented and the edge is not oriented is 2.13 and 1.71. Therefore, it can be seen that the adhesion in the example is higher than that of comparative example 1 and comparative example 2.

[0129] Table 2 shows the Rion measurement data of the comparative example and the example.

[0130] Comparative Example 1 is a battery that has not undergone an orientation process and is therefore not oriented at all.

[0131] Table 2

[0132] Rion is a resistance value that affects the movement of lithium ions. The lower the resistance value, the smoother the movement of lithium ions, and the higher the resistance value, the less smooth the movement of lithium ions.

[0133] Referring to Table 2, Rion of Comparative Example 1 is 27.8, and Rion of Example is 22.7, which means that Rion of Example has a lower value. Therefore, it can be seen that Rion of Example is lower than Rion of Comparative Example 1, so lithium ions can move more smoothly.

[0134] In addition, as the loading level increases and the density of the mixture increases, lithium ions do not move smoothly. However, the loading level (L / L) of Comparative Example 1 is 21.20, and the loading level of the example is 21.78, which shows that although the loading level of the example is higher than that of Comparative Example 1, Rion is still lower in the example.

[0135] Figure 8 is a graph showing dQ / dV according to relative voltage in a comparative example and an example.

[0136] Reference Figure 8 In the graph of the dQ / dV value according to the relative voltage, the more the graph is biased to the left, the more the mobility of lithium ions is improved. Therefore, it can be seen that the graph in the example is further to the left than the comparative example, and therefore, the mobility is improved.

[0137] Table 3 shows the Figure 8 Kinetic measurement data.

[0138] Table 3

[0139] The kinetic value was calculated as the value obtained by dividing the capacity at voltage 0 in the CV data by the C rate.

[0140] Referring to Table 3, when the kinetic value representing the mobility was calculated, the kinetic value of Example was 48.67, which was greater than 47.33 of Comparative Example 1. Therefore, it can be seen that compared with Comparative Example 1, the mobility of Example is improved.

[0141] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those skilled in the art to which the present disclosure belongs. It will also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and / or this specification, and should not be interpreted in an idealized or overly formal sense unless explicitly so defined herein.

[0142] Furthermore, when describing embodiments of the present disclosure, the use of “may” refers to “one or more embodiments of the present disclosure.”

[0143] As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation rather than as terms of degree, and are intended to account for the inherent deviations in measured or calculated values ​​that one of ordinary skill in the art would recognize. As used herein, "substantially" includes the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system). For example, "substantially" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the stated value.

[0144] In addition, any numerical range described herein is intended to include all sub-ranges of the same numerical precision contained in the described range. For example, the range of "1.0 to 10.0" is intended to include all sub-ranges between the described minimum value 1.0 and the described maximum value 10.0 (and including the described minimum value 1.0 and the described maximum value 10.0), that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification and claims to explicitly describe any sub-ranges contained in the range explicitly described herein.

[0145] The portable device, vehicle and / or battery (e.g., battery controller) and / or any other related device or component according to the embodiments of the present disclosure described herein can be implemented using any suitable hardware, firmware (e.g., application specific integrated circuit), software, or a combination of software, firmware and hardware. For example, the various components of the device can be formed on an integrated circuit (IC) chip or on separate IC chips. In addition, the various components of the device can be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on a substrate. In addition, the various components of the device can be processes or threads that execute computer program instructions and interact with other system components to perform various functions described herein, running on one or more processors in one or more computing devices. The computer program instructions are stored in a memory, which can be implemented in a computing device using a standard memory device (such as a random access memory (RAM) as an example). The computer program instructions can also be stored in other non-transitory computer-readable media (such as a CD-ROM, a flash drive, etc. as an example). In addition, those skilled in the art should recognize that without departing from the scope of the embodiments of the present disclosure, the functions of various computing devices can be combined or integrated into a single computing device, or the functions of a particular computing device can be distributed across one or more other computing devices.

[0146] Although the embodiments of the present disclosure have been described, it is understood that the present disclosure should not be limited to these embodiments, but a person skilled in the art may make one or more suitable changes and modifications within the scope of the present disclosure as defined by the appended claims and their equivalents.

[0147] Reference numerals LA: oriented part; LB: non-oriented part 2: substrate; 3: active material layer 3a: lower layer; 3b: upper layer 10: electrode assembly; 11: first electrode 13: second electrode; 12: diaphragm 20: Shell; 21: Curling part 22: crimping part; 30: cover assembly 31: Cover plate; 31a: Center plate 31b: branch part; 31c: connecting plate 31d: discharge port; 32: exhaust plate 32a: exhaust port; 32b: notch 33: insulating member; 34: first auxiliary plate 35: Positive temperature coefficient element; 37: Lead lug 38: second auxiliary plate; 40: gasket 50: insulation board; 51: opening 52: Insulation pad; 60: Center pin.

Claims

1. A negative electrode, comprising: a substrate having a strip shape, wherein a width of the substrate in a first direction is relatively shorter than a length of the substrate in a second direction intersecting the first direction; as well as an active material layer on the substrate and including an oriented portion and a non-oriented portion, the active material layer being arranged in the order of the non-oriented portion, the oriented portion, and the non-oriented portion in the first direction, wherein the alignment portion comprises a lower layer and an upper layer stacked on the substrate, the alignment direction of the lower layer and the alignment direction of the upper layer are different from each other, and Wherein, the negative electrode is used in a rechargeable battery.

2. The negative electrode according to claim 1, wherein: The upper layer includes active material particles oriented at an angle relative to the surface of the substrate, and The lower layer includes active material particles arranged in a direction parallel to the surface of the substrate.

3. The negative electrode according to claim 2, wherein The upper I 002 / I 110 The value is less than the lower layer I 002 / I 110 value.

4. The negative electrode according to claim 2, wherein The angle of the active material particles in the upper layer relative to the surface of the substrate is 10° to 80°.

5. The negative electrode according to claim 1, wherein The orientation part I 002 / I 110 The value is less than the I of the non-oriented part 002 / I 110 value.

6. The negative electrode according to claim 1, wherein The upper layer and the lower layer are made of different active materials.

7. The negative electrode according to claim 1, wherein A width of the alignment portion in the first direction is 10% to 90% of a width of the active material layer in the first direction.

8. The negative electrode according to claim 1, wherein: The thickness of the lower layer is 10% to 90% of the total thickness of the active material layer, and The thickness of the upper layer is 10% to 90% of the total thickness of the active material layer.

9. A rechargeable battery, comprising: A wound electrode assembly comprising the negative electrode according to claim 1, a separator and a positive electrode; A shell for accommodating the wound electrode assembly; a cover plate installed in the opening of the housing to seal the interior of the housing; as well as an electrolyte contained in the casing together with the wound electrode assembly, The first direction is the direction in which the electrolyte is injected into the shell.

10. The rechargeable battery according to claim 9, wherein The wound-type electrode assembly is a cylindrical electrode assembly.

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