Electrode substrate for lithium secondary batteries, and electrodes and lithium secondary batteries containing the same

Abstract

To provide an electrode substrate for lithium secondary batteries that allows for electrical connection between two metal layers even when strip terminals are immediately welded, without the need for separate substrate tabs to electrically connect the metal layers, and simultaneously prevents short circuits during penetration. [Solution] The present invention relates to an electrode substrate for a lithium secondary battery, and an electrode and a lithium secondary battery including the same, wherein the electrode substrate for the lithium secondary battery comprises a first metal layer, an insulating layer located on the first metal layer and containing a polymer, and a second metal layer located on the insulating layer and containing a second metal, wherein the insulating layer has an interconnected pores structure and is divided into a first region and a second region, and the first region further contains a metal that fills the interconnected pores structure in the insulating layer.

Description

Technical Field

[0001] The present invention relates to an electrode substrate for a lithium secondary battery, an electrode containing the same, and a lithium secondary battery.

Background Art

[0002] Lithium secondary batteries are widely used as driving power sources for mobile information terminals such as smartphones and notebook computers because they have a high energy density and are easy to carry. Recently, lithium secondary batteries with high safety and high capacity have been actively studied for use as driving power sources for hybrid vehicles and electric vehicles, or as power storage power sources.

[0003] Due to the continuous consumer needs for high capacity, rapid charging, safety, and weight reduction of lithium secondary batteries, it is necessary to secure technology related to composite substrates. The composite substrate means a current collector having a multilayer structure including metal layers on both sides of a polymer layer. Such a composite substrate, as a normal current collector, can reduce the weight and the amount of metal used by changing a part of a metal thin film (for example, Al for the positive electrode and Cu for the negative electrode) into an insulating layer such as a polymer film, and can prevent the occurrence of a short circuit due to a difference in stretching of internal materials during penetration.

[0004] However, when a strip terminal is connected to such a composite substrate due to the insulating properties of the insulating layer of the composite substrate, there is a problem that electrical connection is made only to one surface of the metal layer and not to the metal layer on the other surface.

[0005] To solve this problem, there is a method of attaching a general substrate tab to one surface of each metal layer and connecting a strip terminal to the general substrate tab. However, according to such a method, there is a problem that the length of the substrate tab becomes long, making assembly difficult and shots may occur.

Summary of the Invention

Problems to be Solved by the Invention

[0006] The objective of one embodiment is to provide an electrode substrate for lithium secondary batteries that can electrically connect two metal layers even when a strip terminal is immediately welded, without the need for a separate substrate tab to electrically connect the metal layers, and at the same time prevent short circuits from occurring during penetration.

[0007] Another object of this embodiment is to provide an electrode including the electrode substrate of the above embodiment.

[0008] Another object of this embodiment is to provide a lithium secondary battery including the electrodes of the above embodiment. [Means for solving the problem]

[0009] One embodiment provides an electrode substrate for a lithium secondary battery, comprising: a first metal layer containing a first metal; an insulating layer located on the first metal layer and containing a polymer; and a second metal layer located on the insulating layer and containing a second metal, wherein the insulating layer has an interconnected pores structure and is divided into a first region and a second region, and the first region further contains a third metal that fills the interconnected pore structure within the insulating layer.

[0010] Another embodiment provides an electrode for a lithium secondary battery, comprising the aforementioned electrode substrate, a strip terminal located on a first region of the electrode substrate, and an active material layer located on a second region of the electrode substrate.

[0011] Another embodiment provides a method for manufacturing an electrode for a lithium secondary battery, which includes the steps of forming an active material layer on one surface of an electrode substrate, attaching a strip terminal to one surface of the electrode substrate having a first metal layer or a second metal layer on which the active material layer is not formed, and dissolving the first metal or the second metal contained in the first metal layer or the second metal layer in the region to which the strip terminal is attached to fill the interconnected pores in the insulating layer.

[0012] Another embodiment provides a lithium secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein at least one of the positive electrode and the negative electrode is an electrode according to one embodiment. [Effects of the Invention]

[0013] In one embodiment, the electrode substrate can electrically connect the two metal layers even when the strip terminal is immediately welded, without the need for a separate substrate tab to electrically connect the metal layers, and at the same time, it can prevent short circuits from occurring when the strip terminal is welded through. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram illustrating the mechanism of a conventional composite substrate during a short circuit. [Figure 2] This is a schematic diagram showing a strip terminal connected to a conventional composite substrate. [Figure 3] This is a schematic cross-sectional view of an electrode substrate according to one embodiment. [Figure 4] This is a schematic diagram showing an electrode substrate or electrode manufactured by a manufacturing method according to one embodiment. [Figure 5] This is a schematic cross-sectional view showing a lithium secondary battery according to one embodiment. [Figure 6] This is a schematic cross-sectional view showing a lithium secondary battery according to one embodiment. [Figure 7] This is a schematic cross-sectional view showing a lithium secondary battery according to one embodiment. [Figure 8] This is a schematic cross-sectional view showing a lithium secondary battery according to one embodiment. [Modes for carrying out the invention]

[0015] Embodiments of the present invention will be described in detail below. However, these are presented as examples only and the present invention is not limited thereto, and the present invention is defined only within the scope of the claims described below.

[0016] Unless otherwise specified herein, when a part such as a layer, film, region, or plate is said to be "on top of" another part, this includes not only when it is "directly on top" of the other part, but also when there is yet another part in between.

[0017] Unless otherwise specified herein, singular nouns may also include plural nouns. Furthermore, unless otherwise specified, "A or B" may mean "containing A, containing B, or containing both A and B."

[0018] In this specification, “these combinations” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the constituents.

[0019] Unless otherwise specified herein, “substitution” means that at least one hydrogen atom in a compound is substituted with a substituent of a halogen atom (F, Cl, Br, I), a hydroxyl group, a C1-C20 alkoxy group, a nitro group, a cyano group, an amine group, an imino group, an azide group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamoyl group, a thiol group, an ester group, an ether group, a carboxyl group or its salt, a sulfonic acid group or its salt, a phosphoric acid or its salt, a C1-C20 alkyl group, a C2-C20 alkenyl group, a C2-C20 alkynyl group, a C6-C30 aryl group, a C3-C20 cycloalkyl group, a C3-C20 cycloalkenyl group, a C3-C20 cycloalkynyl group, a C2-C20 heterocycloalkyl group, a C2-C20 heterocycloalkenyl group, a C2-C20 heterocycloalkynyl group, or a combination thereof.

[0020] Unless otherwise specified herein, “heterocycloalkyl group,” “heterocycloalkenyl group,” “heterocycloalkynyl group,” and “heterocycloalkylene group” mean the presence of at least one N, O, S, or P heteroatom within the cyclic compound of a cycloalkyl, cycloalkenyl, cycloalkynyl, and cycloalkylene, respectively.

[0021] Unless otherwise defined in the chemical formulas herein, the absence of a chemical bond at a position where one should be depicted means that a hydrogen atom is bonded to that position.

[0022] (electrode base material) One embodiment provides an electrode substrate for a lithium secondary battery, comprising a first metal layer containing a first metal, an insulating layer located on the first metal layer and containing a polymer, and a second metal layer located on the insulating layer and containing a second metal, wherein the insulating layer has an interconnected pores structure and is divided into a first region and a second region, and the first region further contains a third metal that fills the interconnected pore structure within the insulating layer.

[0023] The first and second metal layers are elements configured to transmit current to and from the active material during charging and discharging, and perform the function of a commonly known current collector.

[0024] Conventional current collectors typically use thin metal films consisting only of such metal layers. However, when using conventional current collectors, electrical short circuits, thermal runaway, and / or explosions of lithium secondary batteries are unavoidable when deformation occurs due to physical and / or chemical factors.

[0025] Therefore, composite substrates having a metal layer-insulating layer-metal layer structure are known, which replace a portion of the metal thin film of conventional current collectors with an insulating layer such as a polymer film.

[0026] Figure 1 shows that when penetrating a composite substrate, short circuits due to differences in the stretching of the metal layer and the insulating layer can be prevented. However, known insulating layers of composite substrates have a porosity of 0 volume percent and a structure completely filled with an insulator such as a polymer. When a strip terminal is connected, there is a problem that an electrical connection is made only to the metal layer connected to the strip terminal, and not to the other metal layers.

[0027] To solve this problem, a method has been proposed in which a general substrate tab 4 is attached to each metal layer 1, and a strip terminal 5 is connected to the general substrate tab 4, as shown in Figure 2. However, this method has the problem that the length of the general substrate tab becomes long, making assembly difficult and potentially causing shots.

[0028] In one embodiment, the electrode substrate replaces the existing insulating layer, which had a porosity of 0 volume%, with an insulating layer having a porous structure with multiple holes. This allows for electrical connection between two metal layers even when a strip terminal is immediately welded without a separate general substrate tab, while suppressing the occurrence of short circuits during penetration.

[0029] The specific components of the electrode substrate are described in detail below.

[0030] insulating layer The insulating layer according to one embodiment is characterized by having a porous structure with numerous holes, particularly an interconnected pore structure.

[0031] Porous structures have a higher surface area than dense bodies, and such pore structures are classified into open pores and closed pores. Interconnected pore structures mean that the pores are interconnected with each other without any closed pores.

[0032] Figure 3 is a schematic diagram showing an electrode substrate according to one embodiment. As shown in Figure 3, the insulating layer 6 has a pore structure in which each pore 7 is interconnected, and each pore is uniformly distributed and open from one side surface A to the other side surface B of the insulating layer.

[0033] Because the insulating layer 6 has an interconnected pore structure, even if a strip terminal (not shown) is connected to only one of the first metal layer 1 or the second metal layer 1, the entire first and second metal layers can be electrically connected. As will be described later, in the region 9 to which the strip terminal (not shown) is attached, the metal of the first metal layer 1 or the second metal layer 1 can be dissolved by the strip terminal (not shown) and fill the interconnected pores in the insulating layer, and that region may be the first region 9 described later. Also, the region to which the strip terminal 5 is not attached may be the second region 8 described later.

[0034] The size of the pores in the insulating layer may be within the ranges of 50nm to 200nm, 60nm to 180nm, 70nm to 160nm, 80nm to 140nm, or 90nm to 120nm. When the size of the pores in the insulating layer meets these ranges, it is possible to electrically connect all of the first and second metal layers, even without a separate general substrate tab, while effectively suppressing short circuits during penetration, and even when connecting the strip terminal to either the first or second metal layer. The size of the pores can be measured by the BET analysis method.

[0035] The shape of the pores within the insulating layer is not specifically limited, as long as they have an interconnected structure. For example, they may be spherical, cylindrical, crack-shaped, passage-shaped, mesh-shaped, lamellar, etc. In one embodiment, the shape of the pores within the insulating layer may be spherical or mesh-shaped, and the spherical or mesh-shaped pores may have a structure in which they abut and are connected to each other.

[0036] The insulating layer contains a polymer. The polymer may be a thermoplastic or thermosetting resin that has a higher elongation rate than the first and second metal layers, but has a heat distortion temperature lower than the electrolyte ignition temperature.

[0037] Thermoplastic resins include polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polystyrene (PS), acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polyvinylidene chloride (PVDC), polyamide (PA), polyoxymethylene (POM), polycarbonate (PC), polyphenylene ether (PPE), and polybutylene terephthalate (polybutylene ether). This may include terephyhalate (PBT), polysulfone (PSU), polyethersulfone (PES), polyphenylene sulfide (PPS), polyethyleneimine (PEI), or combinations thereof or combinations of monomers comprising them.

[0038] Thermosetting resins may include polyurethane (PU), epoxy, phenolic, polyimide, unsaturated polyester, vinyl polyester, or combinations thereof, or combinations of monomers comprising these.

[0039] The insulating layer may consist mostly of polymers. For example, the polymer content may be 90% or more, 95% or more, 97% or more, 99% or more, 99.9% or more, or 100% or more per 100% by weight of the insulating layer.

[0040] The thickness of the insulating layer can be appropriately adjusted depending on the purpose. The thickness of the insulating layer can be 4 μm to 15 μm, for example, 4 μm to 12 μm, 4 μm to 10 μm, or 4 μm to 8 μm. The thickness of the insulating layer can be appropriately adjusted to prevent short circuits when the strip penetrates and to allow for electrical connection to the strip terminal. The thickness of the insulating layer can be measured by taking a cross-sectional image of the insulating layer with a scanning electron microscope (SEM).

[0041] The insulating layer is divided into a first region and a second region. The first region further contains a third metal that fills the interconnected pore structure within the insulating layer, while the second region exists with the pores in the interconnected pore structure within the insulating layer open.

[0042] The third metal may be the same as or different from the first or second metal described later. In one embodiment, the third metal may be the same as the first or second metal described later. In this case, the third metal may be formed when the first or second metal present in the first or second metal layer melts and fills the interconnected pore structure within the insulating layer during the process of welding a strip terminal to one side of the first or second metal layer.

[0043] The first region may be a region to which a strip terminal is attached to one surface of the first or second metal layer.

[0044] The second region within the insulating layer can exist in an empty state, without other materials (such as a metal like the third metal) filling the pores of the interconnected pore structure.

[0045] The first region within the insulating layer may have very few pores. For example, the porosity of the first region may be less than 10 volume percent relative to 100 volume percent of the insulating layer's porosity, and may be 9 volume percent or less, 8 volume percent or less, 7 volume percent or less, 6 volume percent or less, 5 volume percent or less, 4 volume percent or less, 3 volume percent or less, 2 volume percent or less, 1 volume percent or less, 0.5 volume percent or less, 0.1 volume percent or less, or 0 volume percent. The pores in the first region may be filled with the third metal, resulting in very few or no pores in the first region. If the porosity of the first region within the insulating layer satisfies this range relative to 100 volume percent of the insulating layer's porosity, the two metal layers can be electrically connected by immediately welding strip terminals without the need for separate general substrate tabs.

[0046] The second region within the insulating layer can contain most of the pores within the insulating layer. For example, the porosity of the second region may be more than 90 volume%, 91 volume%, 92 volume%, 93 volume%, 94 volume%, 95 volume%, 96 volume%, 97 volume%, 98 volume%, 99 volume%, 99 volume%, 99.5 volume%, 99.9 volume%, or 100 volume% relative to the 100 volume% porosity of the insulating layer. If the porosity of the second region within the insulating layer meets this range relative to the 100 volume% porosity of the insulating layer, the safety of the battery can be ensured.

[0047] The ratio (B / A) of the porosity of the second region (B) within the insulating layer to the porosity (A) of the insulating layer can satisfy a range of 0.9 to 1. For example, the ratio is 0.9 or greater and 1 or less, and in one embodiment, the ratio may be 1.

[0048] The first region corresponds to a plain area in the electrode substrate, which will be described later, where the active material layer is not applied, and the second region may be an area to which the active material layer, described later, is applied.

[0049] The insulating layer can be manufactured without limitation by any method that has an interconnected porous structure. For example, the insulating layer can be manufactured by pouring molten polymer into a mold, allowing it to solidify, and then etching it, or by manufacturing a spinning solution containing polymer and electrospinning to form a 3D structure made of nanowires.

[0050] Metal layers (first metal layer and second metal layer) Both the first and second metal layers are electrically conductive layers, possessing electrical conductivity in both the planar and thickness directions.

[0051] For example, the first and second metals may each independently include aluminum (Al), nickel (Ni), copper (Cu), iron (Fe), or combinations thereof.

[0052] To give a more detailed example, when the electrode substrate of one embodiment is applied to the positive electrode, the first metal and the second metal can each independently contain aluminum (Al), and when the electrode substrate of one embodiment is applied to the negative electrode, the first metal and the second metal can each independently contain copper (Cu).

[0053] The thickness ratio of the first metal layer to the second metal layer may be 3:7 to 7:3, or 4:6 to 6:4. For example, the thicknesses of the first and second metal layers may be the same.

[0054] The combined thickness of the first and second metal layers may be 40% or less, 30% or less, or 25% or less of the total thickness of the electrode substrate (100%). Within this range, the effects of the first and second metal layers and the effects of the functional layer can be harmonized.

[0055] The first and second metal layers can be formed by vapor deposition, coating, lamination, electroplating, or the like.

[0056] (electrode) One embodiment provides an electrode for a lithium secondary battery, comprising an electrode substrate, a strip terminal located on a first region of the electrode substrate, and an active material layer located on a second region of the electrode substrate.

[0057] The first region of the electrode substrate refers to the region on the electrode substrate when the portion corresponding to the first region of the insulating layer is extended in the thickness direction, and the second region of the electrode substrate refers to the region on the electrode substrate when the portion corresponding to the second region of the insulating layer is extended in the thickness direction.

[0058] The strip terminal serves to electrically connect the external components of the lithium secondary battery (described later) to the electrode substrate.

[0059] The method for manufacturing the electrode is not specifically limited as long as it provides the electrode described.

[0060] According to one embodiment, the method for manufacturing an electrode may include the steps of: forming an active material layer on one surface of an electrode substrate; attaching a strip terminal to one surface of a first metal layer or a second metal layer of an electrode substrate where an active material layer is not formed; and dissolving the first metal or the second metal contained in the first metal layer or the second metal layer in the region to which the strip terminal is attached to fill interconnected pores in the insulating layer.

[0061] The third metal impregnated within the interconnected perforated structure of the insulating layer interconnects the first and second metal layers, allowing the strip terminal to be electrically connected to the other metal layer even when attached to only one of the metal layers. In this case, the third metal may be the same as the metal contained in the metal layer to which the strip terminal is attached. For example, if the strip terminal is attached to the first metal layer, the third metal may be the same as the first metal, and if the strip terminal is attached to the second metal layer, the third metal may be the same as the second metal.

[0062] In other words, the first region may be a region to which a strip terminal is attached to one surface of the first or second metal layer.

[0063] The strip terminal can be attached by welding. This welding can be laser welding or ultrasonic welding. The area where welding takes place may be the entire region where the strip terminal and electrode substrate are attached, and this region is the same as the first region.

[0064] The shape of the welding spot can vary depending on the settings of the laser welding equipment, appearing as multiple points, multiple straight or curved lines, or specific shapes. Welding generates heat, which melts the metal in the metal layer to which the strip terminal is attached, filling the holes inside the insulating layer.

[0065] On the other hand, if the interconnected perforations within the insulating layer of the second region, where the strip terminals are not attached, are impregnated with metal in the metal layer as in the first region, a short circuit will occur upon penetration, preventing the insulating layer from fulfilling its role.

[0066] In other words, the interconnected pore structure within the insulating layer of the first region, where the strip terminal is attached, is impregnated by the metal of the metal layer to which the strip terminal is attached, while the second region, where the strip terminal is not attached, exists in an empty state, with the pores of the interconnected pore structure within the insulating layer not filled with metal.

[0067] Figure 4 is a schematic diagram showing an electrode substrate or electrode manufactured by a manufacturing method according to one embodiment. In the first region 9 to which the strip terminal 5 is attached, the metal of the first metal layer 1 or the second metal layer 2 can be dissolved and fill the interconnected pores in the insulating layer, while in the second region 8 to which the strip terminal 5 is not attached, the pores in the insulating layer can be left open. The active material layer 3 can be located in the second region. With this structure, even if the strip terminal 5 is attached to one surface of the first metal layer 1 or the second metal layer 1 without attaching a general substrate tab, it can be electrically connected, and at the same time, it can prevent electrical short circuits, thermal runaway, and / or explosions of the lithium secondary battery even in the event of deformation due to physical and / or chemical factors by the insulating layer 6.

[0068] The specific details of the electrode substrate are described below in the section on electrode substrates.

[0069] Active material layer (positive electrode active material layer or negative electrode active material layer) The active material layer may contain either a positive electrode active material or a negative electrode active material. If the active material layer contains a positive electrode active material, the electrode substrate may be the positive electrode, and if the active material layer contains a negative electrode active material, the electrode substrate may be the negative electrode.

[0070] The active material layer may be a positive electrode active material layer containing positive electrode active material.

[0071] As the positive electrode active material, a compound that allows for reversible insertion and removal of lithium (lithiated insertion compound) can be used. Specifically, one or more composite oxides of lithium with a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0072] The composite oxides may be lithium transition metal composite oxides, and specific examples include lithium nickel oxides, lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free nickel-manganese oxides, or combinations thereof.

[0073] As an example, a compound represented by any one of the following chemical formulas can be used. Li α A 1-b X b O 2-c D c (0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05); Li a Mn 2-b X b O 4-c D c (0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.5, 0 < α < 2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.5, 0 < α < 2); Li a Ni b Co c L 1 d G e O2(0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.9, 0 ≦ c ≦ 0.5, 0 ≦ d ≦ 0.5, 0 ≦ e ≦ 0.1); Li a NiG b O2(0.90 ≦ a ≦ 1.8, 0.001 ≦ b ≦ 0.1); Li a CoG b O(0.90 ≦ a ≦ 1.8, 0.001 ≦ b ≦ 0.1); Li a Mn 1-b G b O2(0.90 ≦ a ≦ 1.8, 0.001 ≦ b ≦ 0.1); Li a Mn2G b O4(0.90 ≦ a ≦ 1.8, 0.001 ≦ b ≦ 0.1); Li a Mn 1-g G g PO4(0.90 ≦ a ≦ 1.8, 0 ≦ g ≦ 0.5); Li (3-f) Fe2(PO4)3(0 ≦ f ≦ 2); Li a FePO4(0.90 ≦ a ≦ 1.8) In the chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L1 is Mn, Al, or a combination thereof.

[0074] The positive electrode active material may include, for example, a lithium nickel oxide represented by chemical formula 11 below, a lithium cobalt oxide represented by chemical formula 12 below, a lithium iron phosphate compound represented by chemical formula 13 below, a cobalt-free lithium nickel-manganese oxide represented by chemical formula 14, or a combination thereof.

[0075] [Chemical formula 11] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1 In chemical formula 11, 0.9≦a1≦1.8, 0.3≦x1≦1, 0≦y1≦0.7, 0≦z1≦0.7, 0.9≦x1+y1+z1≦1.1, and 0≦b1≦0.1, M 1 and M 2 Each of the elements is independently selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0076] In chemical formula 11, either 0.6 ≤ x1 ≤ 1, 0 ≤ y1 ≤ 0.4, and 0 ≤ z1 ≤ 0.4, or 0.8 ≤ x1 ≤ 1, 0 ≤ y1 ≤ 0.2, and 0 ≤ z1 ≤ 0.2.

[0077] [Chemical formula 12] Li a2 Cox2 M 3 y2 O 2-b2 X b2 In chemical formula 12, 0.9 ≤ a² ≤ 1.8, 0.7 ≤ x² ≤ 1, 0 ≤ y² ≤ 0.3, 0.9 ≤ x² + y² ≤ 1.1, and 0 ≤ b² ≤ 0.1, M 3 X is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0078] [Chemical formula 13] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3 In chemical formula 13, 0.9 ≤ a³ ≤ 1.8, 0.6 ≤ x³ ≤ 1, 0 ≤ y³ ≤ 0.4, and 0 ≤ b³ ≤ 0.1, M 4 X is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0079] [Chemical formula 14] Li a4 Ni x4 Mn y4 M 5 z4 O 2-b4 X b4 In chemical formula 14, 0.9 ≤ a4 ≤ 1.8, 0.8 ≤ x4 < 1, 0 <y4≦0.2、0≦z4≦0.2、0.9≦x4+y4+z4≦1.1、および0≦b4≦0.1でありM 5X is one or more elements selected from the group consisting of Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, Y, Zn, and Zr, and X is one or more elements selected from the group consisting of F, P, and S.

[0080] As an example, the positive electrode active material may be a high-nickel positive electrode active material in which the nickel content relative to 100 mol% of the metal excluding lithium is 80 mol% or more, 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% or more, and 99 mol% or less in a lithium transition metal composite oxide. High-nickel positive electrode active materials can provide high capacity and can therefore be applied to high-capacity, high-density lithium secondary batteries.

[0081] The positive electrode active material layer may further include a binder, a conductive agent, or a combination thereof, along with the positive electrode active material.

[0082] The binder plays a role in ensuring good adhesion between positive electrode active material particles and good adhesion of the positive electrode active material to the current collector. Typical examples of binders include, but are not limited to, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylicated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, and nylon.

[0083] Conductive agents are used to impart conductivity to electrodes, and any electronically conductive material that does not undergo chemical changes in the battery that is constructed can be used. Examples of conductive agents include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fibers, carbon nanofibers, and carbon nanotubes; metallic materials containing copper, nickel, aluminum, silver, etc., in the form of metal powders or metal fibers; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0084] The content of the positive electrode active material is 90% to 99% by weight relative to 100% by weight of the positive electrode active material layer, and the content of the binder and conductive agent may be 0.5% to 5% by weight, respectively, relative to 100% by weight of the positive electrode active material layer.

[0085] The active material layer may be a negative electrode active material layer containing negative electrode active material.

[0086] The negative electrode active material includes a substance capable of reversibly inserting / de-inserting lithium ions, lithium metal, an alloy of lithium metal, a lithium-doped and de-doped substance, or a transition metal oxide.

[0087] Materials capable of reversibly inserting / deinserting lithium ions include carbon-based anode active materials, which may include, for example, crystalline carbon, amorphous carbon, or combinations thereof. Examples of crystalline carbon include graphite such as amorphous, plate-like, flake-like, spherical, or fibrous natural or artificial graphite, while examples of amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, and calcined coke.

[0088] As lithium metal alloys, alloys of lithium with metals selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0089] As a substance capable of being doped and undoped with lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiOx (0 < x ≤ 2), a Si-Q alloy (Q is selected from alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements (excluding Si), Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof), or combinations thereof. The Sn-based negative electrode active material can be Sn, SnO2, a Sn-based alloy, or combinations thereof.

[0090] The silicon-carbon composite can be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite can be in a form in which silicon particles are coated with amorphous carbon on the surface of the silicon particles. For example, it can include secondary particles (cores) formed by granulating primary silicon particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particles. Amorphous carbon can also be located between the primary silicon particles, and for example, the primary silicon particles can be coated with amorphous carbon. The secondary particles can be dispersed and present in an amorphous carbon matrix.

[0091] The silicon-carbon composite can further include crystalline carbon. For example, the silicon-carbon composite can include a core containing crystalline carbon and silicon particles and an amorphous carbon coating layer located on the surface of the core.

[0092] The Si-based negative electrode active material or the Sn-based negative electrode active material can be used by mixing with a carbon-based negative electrode active material.

[0093] The negative electrode active material layer can further include a binder, a conductive agent, or combinations thereof together with the negative electrode active material.

[0094] The binder serves to make the negative electrode active material particles adhere well to each other and also make the negative electrode active material adhere well to the current collector. As the binder, a non-aqueous binder, an aqueous binder, a dry binder, or combinations thereof can be used.

[0095] Examples of non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, or combinations thereof.

[0096] The aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylicated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile-ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0097] When using an aqueous binder as the negative electrode binder, it may further contain a cellulosic compound that can impart viscosity. This cellulosic compound can be a mixture of one or more carboxymethylcellulose, hydroxypropylmethylcellulose, methylcellulose, or alkali metal salts thereof. As the alkali metal, Na, K, or Li can be used.

[0098] The dry binder is a polymeric substance that can be formed into fibers, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0099] Conductive agents are used to impart conductivity to electrodes, and any electronically conductive material that does not undergo chemical changes in the battery that is constructed can be used. Specific examples include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fibers, carbon nanofibers, and carbon nanotubes; metallic materials containing copper, nickel, aluminum, silver, etc., in the form of metal powders or metal fibers; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0100] For example, the negative electrode active material layer may contain 90% to 99% by weight of the negative electrode active material, 0.5% to 5% by weight of the binder, and 0% to 5% by weight of the conductive agent.

[0101] (Lithium-ion secondary battery) Another embodiment provides a lithium secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein at least one of the positive electrode and the negative electrode is the electrode of one embodiment.

[0102] Since the information regarding the positive and negative electrodes is the same as described above, the following will be a detailed explanation of the electrolyte, separators, and other components included in lithium secondary batteries.

[0103] electrolyte Electrolytes for lithium secondary batteries can be, for example, electrolytes, which include non-aqueous organic solvents and lithium salts.

[0104] Non-aqueous organic solvents act as a medium through which ions involved in the electrochemical reactions of batteries can move.

[0105] Non-aqueous organic solvents may be carbonate, ester, ether, ketone, or alcoholic solvents, aprotic solvents, or combinations thereof.

[0106] Examples of carbonate-based solvents that can be used include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), methyl ethyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC). Examples of ester-based solvents that can be used include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanolide, mevalonolactone, valerolactone, and caprolactone. As ether-based solvents, dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, and tetrahydrofuran can be used. As ketone-based solvents, cyclohexanone can be used. As alcohol-based solvents, ethyl alcohol and isopropyl alcohol can be used, and as aprotic solvents, nitriles such as R-CN (where R is a linear, branched, or cyclic hydrocarbon group with 2 to 20 carbon atoms, and can include double bonds, aromatic rings, or ether groups); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane and 1,4-dioxolane; and sulfolanes can be used.

[0107] Non-aqueous organic solvents can be used alone or in combination of two or more.

[0108] Furthermore, when using carbonate-based solvents, cyclic carbonates and linear carbonates can be mixed, and the cyclic carbonates and linear carbonates can be mixed in a volume ratio of 1:1 to 1:9.

[0109] Lithium salts are substances that dissolve in organic solvents and act as a source of lithium ions in batteries, enabling the operation of basic lithium secondary batteries and facilitating the movement of lithium ions between the positive and negative electrodes. Typical examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N(lithium bis(fluorosulfonyl)imide (LiFSI), LiC4F9SO3, and LiN(C x F 2x+1 SO2)(C y F 2y+1 It may contain one or more selected from SO2) (where x and y are integers from 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluorobis(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate) borate (LiBOB).

[0110] Separator Depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. Such separators can be made of polyethylene, polypropylene, polyvinylidene fluoride, or multilayer films of two or more layers of these materials. Mixed multilayer films such as polyethylene / polypropylene two-layer separators, polyethylene / polypropylene / polyethylene three-layer separators, or polypropylene / polyethylene / polypropylene three-layer separators can also be used.

[0111] The separator may include a porous substrate and a coating layer containing organic, inorganic, or a combination thereof located on one or both sides of the porous substrate.

[0112] The porous substrate may be a polymer film formed from one polymer selected from polyethylene, polyolefins such as polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyetherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, polyethylene naphthalate, glass fiber, and polytetrafluoroethylene (e.g., Teflon®), or from a copolymer or mixture of two or more of these polymers.

[0113] The organic material may include polyvinylidene fluoride polymers or (meth)acrylic polymers.

[0114] Inorganic substances include Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, and Mg(OH) 2、 This may include, but is not limited to, inorganic particles selected from boehmite and combinations thereof.

[0115] Organic and inorganic materials can exist mixed together in a single coating layer, or they can exist in a form where a coating layer containing organic materials and a coating layer containing inorganic materials are stacked on top of each other.

[0116] Lithium-ion battery Lithium secondary batteries can be classified into cylindrical, prismatic, pouch-type, coin-type, and other types depending on their form. Figures 5 to 8 are schematic diagrams showing a lithium secondary battery according to one embodiment; Figure 5 is cylindrical, Figure 6 is prismatic, and Figures 7 and 8 are pouch-type batteries. Referring to Figures 5 to 8, the lithium secondary battery 100 may include an electrode assembly 40 with a separator 30 between a positive electrode 10 and a negative electrode 20, and a case 50 in which the electrode assembly 40 is housed. The positive electrode 10, negative electrode 20, and separator 30 may be impregnated with an electrolyte (not shown). The lithium secondary battery 100 may include a sealing member 60 that seals the case 50, as shown in Figure 5. Also, in Figure 6, the lithium secondary battery 100 may include a positive electrode lead tab 11 and a positive electrode terminal 12, a negative electrode lead tab 21, and a negative electrode terminal 22. As shown in Figures 7 and 8, the lithium secondary battery 100 may include electrode tabs 70, namely a positive electrode tab 71 and a negative electrode tab 72, which serve as electrical pathways for guiding the current formed in the electrode assembly 40 to the outside.

[0117] A lithium secondary battery according to one embodiment of the present invention may be applied to automobiles, mobile phones, and / or various forms of electrical devices, but the present invention is not limited thereto.

[0118] Examples and comparative examples of the present invention are described below. However, the following examples are merely one embodiment of the present invention, and the present invention is not limited to the following examples.

[0119] Example 1 Polyethylene terephthalate (PET) was melted as the polymer, poured into a scaffold mold, and allowed to solidify. The mold was then etched to produce an insulating layer with a porous structure having numerous pores, particularly an interconnected pore structure. The thickness of the insulating layer was approximately 6 μm.

[0120] An electrode substrate having a first metal layer-insulating layer-second metal layer structure was manufactured by vaporizing copper as a metal and depositing it onto both sides of the insulating layer. At this time, the thickness of the first metal layer was approximately 1 μm, and the thickness of the second metal layer was approximately 1 μm.

[0121] An active material layer containing graphite as the active material was formed on both sides of the electrode substrate, and a strip terminal was attached to the first metal layer of the electrode substrate where no active material layer was formed.

[0122] Subsequently, the strip terminal was welded, and the metal atoms of the first metal layer received thermal energy, diffusing and impregnating the pores within the insulating layer in the area where the strip terminal was attached. At this time, the pores within the insulating layer in the area where the strip terminal was attached were completely filled with metal atoms, and this area became the first region. The area where the strip terminal was not attached remained vacant, and this area became the second region.

[0123] The porosity of the first region was 0 volume% relative to the 100 volume% porosity of the insulating layer, and the porosity of the second region was 100 volume% relative to the 100 volume% porosity of the insulating layer.

[0124] Comparative Example 1-1 The electrode substrate and electrode were manufactured substantially in the same manner as in Example 1, except that the strip terminal was not attached to the electrode substrate of Example 1 and welded.

[0125] At this time, the insulating layer of the electrode substrate has interconnected pore structures uniformly distributed throughout the entire region, with only the portion corresponding to the second region being present. Therefore, the first metal layer and the second metal layer cannot be electrically connected.

[0126] Comparative Example 1-2 The electrode substrate and electrode were manufactured in the same manner as in Example 1, except that a strip terminal was attached to the electrode substrate of Example 1, and heat was applied to the entire surface of the electrode substrate so that the metal of the metal layer was dissolved and completely impregnated into the interconnected pore structure of the insulating layer, rather than dissolving only a portion of the attached strip terminal.

[0127] At this time, there were no pores in the insulating layer of the electrode substrate, and the metal was completely impregnated into the pores of the interconnected pore structure within the insulating layer, with only the portion corresponding to the first region existing. In the electrodes according to Comparative Example 1-2, the first metal layer and the second metal layer can be electrically connected across the entire insulating layer, but the safety of the battery cannot be ensured during penetration evaluation.

[0128] Example 2 The electrode substrate and electrode were manufactured in substantially the same manner as in Example 1, except that aluminum was vaporized and deposited onto both sides of the insulating layer as a metal layer, and an active material layer containing LiCoO2 as the active material was formed as an active material layer.

[0129] Similar to Example 1, in Example 2, the electrode substrate also had internal pores in the insulating layer of the region to which the strip terminal was attached (i.e., the first region) completely filled with metal atoms, while the region to which the strip terminal was not attached (i.e., the second region) remained pore-filled.

[0130] The porosity of the first region was 0 volume% relative to the 100 volume% porosity of the insulating layer, and the porosity of the second region was 100 volume% relative to the 100 volume% porosity of the insulating layer.

[0131] Comparative Example 2-1 The electrode substrate and electrode were manufactured substantially in the same manner as in Example 2, except that the strip terminal was not attached to the electrode substrate of Example 2 and welded.

[0132] At this time, the insulating layer of the electrode substrate has interconnected pore structures uniformly distributed throughout the entire region, with only the portion corresponding to the second region being present. Therefore, the first metal layer and the second metal layer cannot be electrically connected.

[0133] Comparative Example 2-2 The electrode substrate and electrode were manufactured in the same manner as in Example 2, except that a strip terminal was attached to the electrode substrate of Example 2, and heat was applied to the entire surface of the electrode substrate so that the metal of the metal layer was dissolved and completely impregnated into the interconnected pore structure of the insulating layer, rather than dissolving only a portion of the attached strip terminal.

[0134] At this time, there were no pores in the insulating layer of the electrode substrate, and the metal was completely impregnated into the pores of the interconnected pore structure within the insulating layer, with only the portion corresponding to the first region existing. In the electrode according to Comparative Example 2-2, the first metal layer and the second metal layer can be electrically connected across the entire insulating layer, but the safety of the battery cannot be ensured during penetration evaluation.

[0135] While preferred embodiments of the present invention have been described above, the present invention is not limited thereto. It can be modified and implemented in various ways within the scope of the claims, the detailed description of the invention, and the accompanying drawings, and these modifications naturally also fall within the scope of the present invention. [Explanation of symbols]

[0136] 1: Metal layer 2: Insulating layer of known composite substrate 3: Active material layer 4: General base material tab 5: Strip Terminal 6: Insulating layer 7: Hole 8:Second area 9:First area A: One side surface B: Other side surface 100: Lithium-ion rechargeable battery 10: Positive electrode 11: Positive lead tab 12: Positive terminal 20: Negative electrode 21: Negative lead tab 22: Negative terminal 30: Separator 40: Electrode assembly 50: Case 60: Sealing member 70: Electrode Tab 71: Positive Tab 72: Negative electrode tab

Claims

1. A first metal layer containing the first metal, An insulating layer located on the first metal layer and containing a polymer, A second metal layer located on the insulating layer and containing a second metal, The insulating layer has an interconnected pore structure and is divided into a first region and a second region, the first region further comprising a third metal that fills the interconnected pore structure within the insulating layer. Electrode substrate for lithium secondary batteries.

2. The insulating layer has a porous structure in which each pore is uniformly distributed and open from one side surface to the other side surface of the insulating layer. The electrode substrate for a lithium secondary battery according to claim 1.

3. The size of the pores in the insulating layer is 50 nm to 200 nm. The electrode substrate for a lithium secondary battery according to claim 1.

4. The polymer is a thermoplastic resin or a thermosetting resin. The electrode substrate for a lithium secondary battery according to claim 1.

5. The content of the polymer is 90% by weight or more relative to 100% by weight of the insulating layer. The electrode substrate for a lithium secondary battery according to claim 1.

6. The thickness of the insulating layer is 4 μm to 15 μm. The electrode substrate for a lithium secondary battery according to claim 1.

7. The third metal is the same as or different from the first or second metal. The electrode substrate for a lithium secondary battery according to claim 1.

8. The porosity of the first region within the insulating layer is less than 10 volume percent relative to the porosity of the insulating layer at 100 volume percent. The electrode substrate for a lithium secondary battery according to claim 1.

9. The porosity of the second region within the insulating layer is 90 volume% greater than the porosity of the insulating layer at 100 volume%. The electrode substrate for a lithium secondary battery according to claim 1.

10. The ratio (B / A) of the porosity of the second region (B) within the insulating layer to the porosity (A) of the insulating layer is 0.9 to 1. The electrode substrate for a lithium secondary battery according to claim 1.

11. The first metal and the second metal each independently include a metal that is aluminum (Al), nickel (Ni), copper (Cu), iron (Fe), or a combination thereof. The electrode substrate for a lithium secondary battery according to claim 1.

12. The sum of the thicknesses of the first metal layer and the second metal layer is 40% or less of the total thickness of the electrode substrate (100%). The electrode substrate for a lithium secondary battery according to claim 1.

13. Electrode substrate according to any one of claims 1 to 12; A strip terminal located on the first region of the electrode substrate; and The electrode substrate includes an active material layer located on the second region, Electrodes for lithium-ion secondary batteries.

14. The active material layer includes a positive electrode active material or a negative electrode active material. The electrode for a lithium secondary battery according to claim 13.

15. Steps include forming an active material layer on one surface of the electrode substrate, The step of attaching a strip terminal to one side of the first metal layer or the second metal layer of an electrode substrate in which no active material layer has been formed, A method for manufacturing an electrode for a lithium secondary battery according to claim 13, comprising the step of dissolving the first metal or the second metal contained in the first metal layer or the second metal layer in the region to which the strip terminal is attached to fill interconnected pores in the insulating layer.

16. It includes a positive electrode, a negative electrode, and an electrolyte, At least one of the positive electrode and the negative electrode is the electrode described in claim 13. Lithium-ion rechargeable battery.

17. The lithium secondary battery according to claim 16, further comprising a separator impregnated with the electrolyte between the positive electrode and the negative electrode.

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