Electrode current collector and lithium secondary battery including same

Abstract

An electrode current collector according to the present invention includes: a resin layer; a first metal layer disposed on one surface of the resin layer; and a second metal layer disposed on the other surface of the resin layer, wherein the first metal layer and the second metal layer each independently have a thickness of 3.0 ㎛ or less, the resin layer includes a metal oxide, and a thickness ratio (R) of the resin layer to the first metal layer or the second metal layer is 1 to 24. Thus, the present invention has advantages of significantly contributing to the improvement of battery safety, reducing electrical resistivity despite of the structure of the resin layer that is disposed between the metal layers, and also improving weldability.

Description

Electrode current collector and lithium secondary battery including the same The present invention relates to an electrode current collector and a lithium secondary battery including the same, and more particularly, to an electrode current collector capable of simultaneously achieving safety assurance and battery performance improvement, and a lithium secondary battery including the same. As technological development and demand for electric vehicles and energy storage systems (ESS) increase, the demand for batteries as an energy source is rapidly increasing, and research is being conducted on batteries that can meet various needs. In particular, to achieve longer battery life on a single charge, batteries need to be increased in capacity, and this requires large-area electrode technology. However, the process of increasing the electrode area can degrade electrode performance, and there are concerns about thermal runaway and heat propagation to other electrodes in the event of a fire. Lithium secondary batteries can experience rapid temperature increases in the electrodes due to thermal and physical factors. Thermal factors include overcharging or overloading caused by misuse or malfunctioning chargers. Physical factors include damage to the separator due to external impact, causing contact between the cathode and anode materials, resulting in an internal short circuit, which can cause rapid temperature increases in the electrodes. Such rapid temperature increases can cause the electrolyte and lithium to react, or hydrogen and oxygen to be generated within the battery, making the battery highly unstable. Furthermore, the electrolyte solvent can decompose, generating gas, which can ignite and potentially cause an explosion. Conventional lithium secondary batteries typically incorporate a single metal layer as an electrode current collector. Specifically, an aluminum single metal layer is used as the positive electrode current collector, and a copper single metal layer is used as the negative electrode current collector. However, these single metal layers exhibit extremely high electrical and thermal conductivities, leading to concerns about thermal propagation due to thermal runaway, which can occur during the battery's abnormal behavior and in the shortest time possible. Accordingly, by using an electrode current collector (metallized film) including a resin layer sandwiched between two metal layers instead of a conventional electrode current collector, it is possible to reduce the weight compared to an electrode current collector made of metal, thereby dramatically improving the energy density per weight, and can improve safety by short-circuiting between electrodes in the event of a fire. However, in the case of the electrode current collector, which is the metallized film, there is a problem that the electrical resistivity may be high because it has a structure with a resin layer interposed in the middle compared to the existing pure metal electrode current collector, so research is needed on a method to minimize the loss of electrical resistivity. The present invention is intended to solve the above problems, and to provide an electrode current collector and a lithium secondary battery including the same, which includes particles having both conductor and insulator properties in a resin layer of a metallized film current collector, thereby functioning as a conductor during charging and discharging of the battery to improve electrical conductivity and thereby improve the output characteristics of the battery, and which not only maintains the insulating properties of the resin layer when a thermal event occurs, thereby providing excellent stability from fire and prevention of thermal runaway, but also enables weight reduction to improve energy density. [1] An electrode current collector according to one embodiment of the present invention comprises a resin layer; a first metal layer disposed on one surface of the resin layer; and a second metal layer disposed on the other surface of the resin layer, wherein the first metal layer and the second metal layer each independently have a thickness of 3.0 ㎛ or less, the resin layer includes a metal oxide, and the thickness (T) of the first metal layer or the second metal layer M ) for the thickness of the resin layer (T R ) of the ratio (T R / T M ) is 1 to 24, and the resin layer includes a metal oxide represented by the following chemical formula 1. [Chemical Formula 1] M1 x M2 y O z In the above chemical formula 1, M1 is one or more post-transition metals selected from the group consisting of Al, Ga, In, Sn, Pb, and Bi, M2 is one or more transition metals selected from the group consisting of Ti, Zr, Nb, Ru, Hf, Cr, Mo, Ni, Co, V, Y, and Zn, 0≤x≤4, 0≤y≤4, and 1≤z≤8, x and y cannot be 0 at the same time, and x, y, and z are defined in consideration of the oxidation numbers of M1 and M2 and the oxidation number of oxygen. [2] In the above [1], the metal oxide may include at least one selected from the group consisting of lead oxide (PbO), ruthenium dioxide (RuO2), alumina (Al2O3), zirconia (ZrO2), bismuth ruthenic acid (Bi2Ru2O7), and bismuth iridic acid (Bi2Ir2O7). [3] In the above [1] and / or [2], the metal oxide may be 10 wt% to 60 wt% based on the total weight of the resin layer. [4] In any one or more of the above [1] to [3], the metal oxide may have an average particle diameter of 0.5 ㎛ to 2.0 ㎛. [5] In any one or more of the above [1] to [4], the resin layer may further include at least one selected from the group consisting of polyester resin, epoxy resin, phenol resin, melamine resin, urethane resin, silicone resin, vinyl acetate resin, rubber resin, acrylic resin, and polyetherurethane resin. [6] In any one or more of the above [1] to [5], the first metal layer and the second metal layer may each independently include at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon, and aluminum-cadmium alloy. [7] In any one or more of the above [1] to [6], the resin layer may have a thickness of 2 µm to 12 µm. [8] In any one or more of the above [1] to [7], the first metal layer and the second metal layer may have a thickness of 0.2 µm to 2.5 µm, respectively. [9] In any one or more of the above [1] to [8], the resin layer may have a thickness deviation of 10% or less.

[0010] In any one or more of the above [1] to [9], the first metal layer and the second metal layer may each independently have a thickness deviation of 5% or less.

[0011] According to another embodiment of the present invention, a lithium secondary battery includes an electrode assembly having a structure in which a plurality of electrodes and a plurality of separators are alternately laminated, wherein the electrode includes an electrode current collector and an electrode active material layer disposed on the electrode current collector, and at least one of the plurality of electrode current collectors is the aforementioned electrode current collector.

[0012] A battery module according to another embodiment of the present invention includes a plurality of the aforementioned lithium secondary batteries. The electrode current collector according to the present invention includes a resin layer between two metal layers, and the resin layer includes a metal oxide that can have both conductor and insulator properties depending on the surrounding environment, so that the flow of current can be improved even within the resin layer when the battery is operated, and thus has the advantage of being able to lower the electrical resistivity of the metallized film, and also having the advantage of ensuring safety when a thermal event occurs due to the insulating properties of the resin layer of the metallized film. Furthermore, the electrode current collector may also have the advantage of being able to improve the problem of poor weldability due to the resin layer interposed between the electrode tab and the welding process by the metal component included in the metal oxide. In addition, the lithium secondary battery according to the present invention can improve safety by delaying thermal propagation in the event of an actual fire, as well as mechanical safety against foreign substances such as nail penetration, because the metal oxide included in the resin layer of the electrode current collector functions as an insulator when an event occurs and maintains the insulation of the resin layer. In addition, since it includes an electrode current collector having a structure in which a relatively light resin layer and a metal layer are arranged as a thin film on the resin layer compared to an electrode current collector made only of metal, the weight of the battery can be reduced, thereby improving the energy density per weight. FIG. 1 is an example of a cross-sectional view of an electrode current collector according to one embodiment of the present invention. FIG. 2 is another example of a cross-sectional view of an electrode current collector according to one embodiment of the present invention. The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided only to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification. Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used in their common sense to those of ordinary skill in the art to which the present invention pertains. Furthermore, terms defined in commonly used dictionaries are not to be interpreted ideally or excessively unless explicitly and specifically defined otherwise. The terminology used herein is for the purpose of describing embodiments and is not intended to limit the present invention. In this specification, singular forms also include plural forms, unless specifically stated otherwise. As used herein, the terms "comprises" and / or "comprising" do not exclude the presence or addition of one or more other components in addition to the components mentioned. In this specification, when it is said that a part includes a certain component, this does not mean that other components are excluded, but rather that other components may be included, unless specifically stated otherwise. In this specification, the description of “A and / or B” means A, or B, or A and B. In this specification, “%” means weight percent unless explicitly indicated otherwise. In this specification, "average particle size" means the particle size corresponding to the average value of weight percentages in a particle size distribution curve, and unless otherwise explicitly indicated, means weight %. The above average particle size can be measured using an electron microscope or optical microscope after cutting a sample of a pouch-type battery case. In this specification, each of the electrode current collector, lithium secondary battery and battery module includes at least one of the technical features and / or technical configurations described below, and these technical features and / or technical configurations can be combined in various ways. Electrode current collector An electrode current collector according to one embodiment of the present invention includes a resin layer; a first metal layer disposed on one surface of the resin layer; and a second metal layer disposed on the other surface of the resin layer. In addition, the first metal layer and the second metal layer each independently have a thickness of 3.0 ㎛ or less, the resin layer includes a metal oxide represented by the following chemical formula 1, and the thickness (T) of the first metal layer or the second metal layer M ) for the thickness of the resin layer (T R ) of the ratio (T R / T M ) is 1 to 24. [Chemical Formula 1] M1 x M2 y O z In the above chemical formula 1, M1 is one or more post-transition metals selected from the group consisting of Al, Ga, In, Sn, Pb, and Bi, M2 is one or more transition metals selected from the group consisting of Ti, Zr, Nb, Ru, Hf, Cr, Mo, Ni, Co, V, Y, and Zn, 0≤x≤4, 0≤y≤4, and 1≤z≤8, x and y cannot be 0 at the same time, and x, y, and z are defined in consideration of the oxidation numbers of M1 and M2 and the oxidation number of oxygen. Hereinafter, the electrode current collector according to the present invention will be described with reference to FIGS. 1 and 2. Figures 1 and 2 illustrate cross-sectional views of an electrode current collector according to one embodiment of the present invention. Referring to FIG. 1, an electrode current collector according to one embodiment of the present invention includes a resin layer (11), a first metal layer (12) disposed on one surface of the resin layer, and a second metal layer (13) disposed on the other surface of the resin layer, and the resin layer includes a metal oxide (14). Or, as in Fig. 2, a resin layer may be formed between the first metal layer (12) and the second metal layer (13) to form a three-layer structure in total, wherein the first resin layer (11b) may be arranged to be in contact with the second metal layer (12) among the resin layers, the third resin layer (11c) may be arranged to be in contact with the second metal layer (13), and the metal oxide (14) may have a structure in which it is included in the first resin layer (11a) located at the innermost side. Conventional lithium secondary batteries contain only a single metal layer as an electrode current collector. Specifically, an aluminum single metal layer is used as a positive electrode current collector, and a copper single metal layer is used as a negative electrode current collector. However, these single metal layers have very high electrical and thermal conductivities, which means that the time it takes for the battery to reach a high temperature instantaneously is very short, and there are concerns about thermal propagation due to thermal runaway, and there is also a high risk of explosion in the event of penetration damage by a needle-like object. Accordingly, by using an electrode current collector including a resin layer sandwiched between two metal layers instead of a conventional electrode current collector, the weight can be reduced compared to an electrode current collector made of metal, thereby dramatically improving the energy density per weight. In addition, in the event of a fire, the insulating properties of the resin layer between the metal layers can delay heat transfer, and the risk of explosion can be reduced even in the event of penetration damage. However, since the above electrode current collector has a structure in which a resin layer is interposed between metal layers, the current flow path is bound to be reduced compared to a conventional current collector, and an increase in electrical resistance is inevitable as a result, and many problems are also caused when welding with the electrode tab. To solve these problems, one can consider inserting metal powder into the resin layer to improve electrical conductivity and weldability, but in this case, if a small amount or small particles are inserted, no improvement is observed, and if the metal powder is inserted at a level that improves electrical conductivity and weldability, the characteristics of the current collector, which is a metallized film for delaying heat transfer, cannot be utilized, and there is a problem of showing stability that is vulnerable to penetration damage. Furthermore, when using carbon materials such as carbon black, graphene, and graphite as conductive materials in electrodes to improve electrical conductivity, it is difficult to expect safety, just like when using metal powder, and there is a problem that weldability is not improved at all. Accordingly, the inventors of the present invention have designed an electrode current collector that can solve the problem of electrical resistivity while also improving weldability by improving and increasing the flow path of current by inserting a metal oxide into the resin layer of the electrode current collector, which is a metallized film, and ultimately secure safety against heat transfer delay and penetration damage that are intended to be achieved with the metallized film. metal oxide According to one embodiment of the present invention, the electrode current collector is characterized by including a metal oxide in the resin layer. The resin layer disposed in the middle of the electrode current collector is not electrically conductive and has a high electrical resistivity, which may be a factor hindering the performance of the electrode current collector's function. However, by including the metal oxide in the resin layer, the dielectric properties of the metal oxide can be utilized to function as a conductor in a current-flowing situation, thereby reducing the high electrical resistivity due to the resin layer. Additionally, if the battery is damaged by external impact, particularly if the battery is penetrated by a needle-like object, the resin layer can help delay heat transfer by preventing electrical shorts of the electrodes, as the metal oxide itself is an insulator. The metal oxide may be, for example, one represented by the following chemical formula 1. [Chemical Formula 1] M1 x M2 y O z In the above chemical formula 1, M1 is a post transition metal, M2 is a transition metal, 0≤x≤4, 0≤y≤4 and 1≤z≤8, x and y cannot be 0 at the same time, and x, y and z can be defined by taking into consideration the oxidation numbers of M1 and M2 and the oxidation number of oxygen. Specifically, the M1 may be Al, Ga, In, Sn, Pb, or Bi, and the M2 may be Ti, Zr, Nb, Ru, Hf, Cr, Mo, Ni, Co, V, Y, or Zn. Preferably, the composite metal oxide may include at least one selected from the group consisting of lead oxide (PbO), ruthenium dioxide (RuO2), alumina (Al2O3), zirconia (ZrO2), bismuth ruthenic acid (Bi2Ru2O7), and bismuth iridic acid (Bi2Ir2O7). Meanwhile, as described above, when the metal oxide is replaced with a metal or carbon material, it may be difficult to achieve the effect of replacing a single metal film with a metallized film. That is, when the resin layer, which is the intermediate layer of the metallized film, contains relatively highly conductive materials such as carbon materials or metals rather than metal oxides, the possibility of a short circuit occurring when the current collector is damaged increases, causing problems such as explosion upon penetration or accelerated heat transfer, and although the probability is low, it may cause problems such as dendrite growth in which lithium is precipitated due to the generation of leakage current. Therefore, the material included as a filler in the resin layer needs to be a metal oxide. The metal oxide may be included in an amount of 10 wt% to 60 wt% based on the total weight of the resin layer, preferably 15 wt% or more, 20 wt% or more, or 25 wt% or more, and preferably 55 wt% or less, or 50 wt% or less. When the metal oxide is included in an amount within the above range, the effect of improving the current flow path can be maximized, while preventing problems such as an electrical short caused by external impact or penetration of a needle-like object, similar to a conventional electrode current collector, from having a negative effect on improving the weight reduction if included in an excessive amount. In addition, it may be preferable to include at least 10 wt% in order to see the effect of improving the current flow path. In addition, the metal oxide may have an average particle size of 0.5 ㎛ to 2.0 ㎛, preferably 0.7 ㎛ or more, 1.0 ㎛ or more, or 1.2 ㎛ or more, and preferably 2.0 ㎛ or less, 1.8 ㎛ or less, or 1.5 ㎛ or less. This average particle size may be appropriately selected in consideration of the thickness of the resin layer, and may be selected in consideration of the type and density of the material of the metal oxide to be applied. Thickness and thickness ratio of metal layer According to one embodiment of the present invention, the electrode current collector has a first metal layer and a second metal layer each independently having a thickness of 3.0 μm or less, and the thickness (T) of the first metal layer or the second metal layer M ) for the thickness of the resin layer (T R ) of the ratio (T R / T M ) is 1 to 24. In cases where the metal oxide is included in the resin layer, in order to achieve effects such as weight reduction, improved safety, and reduced resistivity of the battery, the thickness of the metal layer and the thickness ratio of the resin layer and the metal layer must be considered together. Even if the metal oxide is included, if the thickness of the metal layer or the thickness ratio of these layers is not properly controlled, it is difficult to normally achieve the intended effect through the introduction of the metal oxide. Accordingly, the electrode current collector according to one embodiment of the present invention is characterized in that each of the metal layers positioned on both sides of the resin layer has a thickness of 3.0 ㎛ or less. The metallized film, that is, the electrode current collector of the present invention, can be expected to improve energy density through weight reduction without affecting the original function of the current collector. However, when the thickness of each metal layer exceeds 3.0 ㎛, it is difficult to expect such an effect, and since the possibility of heat transmission due to thermal runaway occurring increases as the thickness of the metal layer becomes thicker, it is preferable that the thickness of the metal layer does not exceed 3.0 ㎛ in order to ensure improved safety. The thickness of each of the above metal layers may preferably be 0.2 μm or more, 0.5 μm or more, 0.7 μm or more, and more preferably 1.0 μm or more, 2.5 μm or less, 2.3 μm or less, or 2.0 μm or less. In this case, the effects described above can be more easily implemented. In addition, the metal oxide can be included in the resin layer to improve the current flow path, but in order to see this effect, the thickness ratio of the metal layer and the resin layer needs to be 1 to 24. If the thickness ratio is less than 1, the resin layer becomes too thin, making it difficult to ensure safety in the event of a short circuit due to external impact or penetration by a needle-like object. In addition, if the thickness ratio exceeds 24, there is a concern that the resin layer becomes too thick, lowering the energy density, and even if the metal oxide is introduced, the current flow path is not improved, making it impossible to obtain the effect of reducing the resistivity. The thickness ratio of the resin layer and the metal layer may have a lower limit of 1 or more, preferably 1.5 or more, 2 or more, 2.5 or more, 3 or more, 3.5 or more, or 4 or more, and an upper limit of 24 or less, preferably 23 or less, 22 or less, 21 or less, or 20 or less. resin layer According to one embodiment of the present invention, the resin layer (11) is a matrix resin that prevents abnormal heat transfer between the electrode current collector and the electrode active material layer, and can also play a role in reducing the weight of the electrode current collector and alleviating external impact. As described above, the resin layer (11) includes a metal oxide, and since the description of the metal oxide is the same as described above, its description is omitted. The above resin layer (11) may include, for example, at least one selected from the group consisting of polyester resin, epoxy resin, phenol resin, melamine resin, urethane resin, silicone resin, vinyl acetate resin, rubber resin, acrylic resin, and polyetherurethane resin. Specifically, the resin layer (11) may include at least one selected from the group consisting of polyimide (PI), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyacrylonitrile (PAN), polyethylene (PE), polyamide (PA), and polypropylene (PP). In addition, the resin layer (11) may be a thermosetting resin or a photocurable resin, and preferably may include an ultraviolet-curable resin. If necessary, the resin layer (11) may include a photoinitiator such as a benzoin compound, an acetophenone compound, an acylphosphine oxide compound, a titanocene compound, a thioxanthone compound, or a peroxide compound, or a photoinitiator such as an amine or a quinone, and may additionally include a curing accelerator such as an amine-based, imidazole-based, phosphorus-based, boron-based, or phosphorus-boron-based. In addition, it may include a thermal initiator such as a peroxide such as azobisnitrile, benzoyl peroxide, or acetyl peroxide. According to one embodiment of the present invention, the resin layer (11) may have a thickness of 2 µm to 12 µm, preferably a lower limit of 3 µm or more, 4 µm or more, 5 µm or more, or 6 µm or more, and an upper limit of preferably 11 µm or less, 10 µm or less, 9 µm or less, or 8 µm or less. When the thickness of the resin layer (11) is applied within this range, effects such as a function of preventing abnormal heat transfer, a function of reducing the weight of the electrode current collector, a function of alleviating external impact, and a function of preventing an increase in the overall thickness of the battery can be expected. In addition, the resin layer (11) may have a thickness deviation of 10% or less. It may be desirable to control the thickness deviation of the resin layer to be 10% or less, in which case the bonding surface of the resin layer and the metal layer can be densely bonded without any gaps, and problems such as fire caused by short circuit between the metal layers due to damage caused by external impact or penetration of a needle-like object can be prevented. metal layer According to one embodiment of the present invention, the first metal layer (12) and / or the second metal layer (13) may include at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon, and an aluminum-cadmium alloy. Although not particularly limited, when forming a positive electrode current collector, it is preferable to include aluminum, and when forming a negative electrode current collector, it is preferable to include copper. Since the thickness of each of the above metal layers has been described above, its description is omitted. In addition, the first metal layer (12) and / or the second metal layer (13) may form fine irregularities on the surface to strengthen the bonding strength with the electrode combination layer, and may be used in various forms such as a film, sheet, foil, net, porous body, foam, or non-woven fabric. However, even when forming fine irregularities on the surface, it may be desirable for the deviation in the thickness of the metal layer to be 5% or less. Although forming irregularities on the surface can improve the adhesion to the electrode mixture layer, if the deviation between the highest and lowest thicknesses of the irregularities exceeds 5% due to the formation of irregularities, problems such as fire caused by short circuits between the metal layers due to damage from external impact or penetration by needle-like objects may occur. An electrode current collector (10) according to one embodiment of the present invention includes a resin layer (11) and a first metal layer (12) and a second metal layer (13) on both sides thereof, respectively, and a metal oxide (14) is included in the resin layer (11). The metal oxide can be inserted into the resin layer by a method such as introducing the polymer, which is a material of the resin layer, in a molten state and extruding them together, and the metal layer can be formed on the resin layer by, for example, a physical vapor deposition method. There is no particular limitation on the method as long as it is capable of manufacturing the electrode current collector of the present invention that satisfies the conditions described above, but in order to form the metal layer as thin as possible, it may be preferable to form it by a physical vapor deposition method. lithium secondary battery A lithium secondary battery according to the present invention includes the electrode current collector of the present invention described above. Specifically, the lithium secondary battery includes an electrode assembly having a structure in which a plurality of electrodes and a plurality of separators are alternately laminated, the electrode includes an electrode current collector and an electrode active material layer disposed on the electrode current collector, and at least one of the plurality of electrode current collectors is the electrode current collector of the present invention described above. More specifically, a lithium secondary battery according to the present invention includes an electrode assembly in which a positive electrode, a separator, and a negative electrode are sequentially laminated, the separator being disposed between the positive electrode and the negative electrode, the positive electrode including a positive electrode current collector and a positive electrode active material layer laminated on the positive electrode current collector, the negative electrode including a negative electrode current collector and a negative electrode active material layer laminated on the negative electrode current collector, and at least one of the positive electrode current collector and the negative electrode current collector is the electrode current collector of the present invention described above. anode According to one embodiment of the present invention, the positive electrode may apply a metallized film as described above as a positive electrode current collector, and may include the positive electrode current collector and a positive electrode active material layer disposed thereon. The above positive electrode active material layer may optionally include a conductive material and a binder, together with the positive electrode active material, as needed. The above positive electrode active material is a material capable of causing an electrochemical reaction, and is a lithium transition metal oxide, containing two or more transition metals, for example, a layered compound such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2) substituted with one or more transition metals; lithium manganese oxide substituted with one or more transition metals; chemical formula LiNi 1-y M y Lithium nickel oxide represented by O2 (wherein, M = Co, Mn, Al, Cu, Fe, Mg, B, Cr, Zn or Ga and containing one or more of the above elements, 0.01≤y≤0.7); Li 1+z Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O2, Li 1+z Ni 0.4 Mn 0.4 Co 0.2 Li, such as O2 1+z Ni b Mn c Co 1-(b+c+d) M d O (2-e) A e (wherein, -0.5≤z≤0.5, 0.1≤b≤0.8, 0.1≤c≤0.8, 0≤d≤0.2, 0≤e≤0.2, b+c+d<1, M = Al, Mg, Cr, Ti, Si or Y, and A = F, P or Cl) lithium nickel cobalt manganese composite oxide; chemical formula Li 1+x M 1-y M' y PO 4-z X z(wherein, M = transition metal, preferably Fe, Mn, Co or Ni, M' = Al, Mg or Ti, X = F, S or N, and -0.5≤x≤+0.5, 0≤y≤0.5, 0≤z≤0.1) and olivine-based lithium metal phosphates, etc., are mentioned, but are not limited thereto. The positive electrode active material may be included in an amount of 80 wt% to 99 wt%, preferably 90 wt% to 98 wt%, based on the total weight of the positive electrode active material layer. The conductive material is used to provide conductivity to the electrode, and in the battery to be formed, as long as it does not cause a chemical change and has electronic conductivity, it can be used without any particular limitation. Specific examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive tubes such as carbon nanotubes; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives, and the like. One of these may be used alone or a mixture of two or more may be used. The conductive material may be included in an amount of 0.01 wt% to 10 wt%, preferably 0.1 wt% to 9 wt%, and more preferably 0.1 wt% to 5 wt%, based on the total weight of the positive electrode active material layer. The above binder serves to improve the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the current collector. Specific examples include polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylalcohol, polyacrylonitrile, polymethyl methacrylate, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene butadiene rubber (SBR), fluoroelastomer, polyacrylic acid, and polymers in which hydrogens of these are substituted with Li, Na, or Ca, or various copolymers thereof, and one of these may be used alone or a mixture of two or more thereof. The above binder may be included in an amount of 1 wt% to 30 wt%, preferably 1 wt% to 20 wt%, and more preferably 1 wt% to 10 wt%, based on the total weight of the positive electrode active material layer. The above-mentioned positive electrode can be manufactured according to a conventional positive electrode manufacturing method, except that the above-mentioned positive electrode active material is used. Specifically, the positive electrode slurry composition, prepared by dissolving or dispersing the above-mentioned positive electrode active material and optionally a binder, a conductive agent, and a dispersant in a solvent as needed, is applied onto a positive electrode current collector, followed by drying and rolling. The solvent may be a solvent generally used in the relevant technical field, such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), dimethyl formamide (DMF), acetone, or water. One of these may be used alone or a mixture of two or more thereof may be used. The amount of the solvent used is sufficient to dissolve or disperse the positive electrode active material, conductive material, binder, and dispersant in consideration of the coating thickness and manufacturing yield of the slurry, and to have a viscosity that can exhibit excellent thickness uniformity when applied thereafter for manufacturing the positive electrode. Alternatively, the positive electrode may be manufactured by casting the positive electrode slurry composition onto a separate support, peeling the resulting film from the support, and laminating the resulting film onto a positive electrode current collector. membrane The above separator separates the negative electrode and the positive electrode and provides a passage for lithium ions to move. Any separator commonly used in lithium secondary batteries can be used without any particular restrictions, and in particular, one having low resistance to ion movement of the electrolyte and excellent electrolyte moisture retention capacity is preferable. Specifically, a porous polymer film, for example, a porous polymer film made of a polyolefin polymer such as an ethylene homopolymer, a propylene homopolymer, an ethylene / butene copolymer, an ethylene / hexene copolymer, and an ethylene / methacrylate copolymer, or a laminated structure of two or more layers thereof, may be used. In addition, a conventional porous nonwoven fabric, for example, a nonwoven fabric made of high-melting-point glass fiber, polyethylene terephthalate fiber, etc. may be used. In addition, a coated separator containing a ceramic component or a polymer material to secure heat resistance or mechanical strength may be used, and may optionally be used in a single-layer or multi-layer structure. electrolyte In addition, examples of the electrolyte used in the present invention include, but are not limited to, organic liquid electrolytes, inorganic liquid electrolytes, solid polymer electrolytes, gel-type polymer electrolytes, solid inorganic electrolytes, and molten inorganic electrolytes that can be used in the manufacture of lithium secondary batteries. Specifically, the electrolyte may include an organic solvent and a lithium salt. The organic solvent may be used without any particular limitation as long as it can serve as a medium through which ions involved in the electrochemical reaction of the battery can move. Specifically, the organic solvent may include ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; Carbonate solvents such as dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (MEC), ethylmethylcarbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R represents a linear, branched, or cyclic hydrocarbon group having 2 to 20 carbon atoms and may include a double-bonded aromatic ring or an ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes can be used. Among these, a carbonate solvent is preferable, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate, etc.) having high ionic conductivity and high dielectric constant that can improve the charge / discharge performance of the battery and a linear carbonate compound having low viscosity (e.g., ethyl methyl carbonate, dimethyl carbonate, or diethyl carbonate, etc.) is more preferable. The above lithium salt can be used without any special limitation as long as it is a compound that can provide lithium ions used in a lithium secondary battery. Specifically, the anion of the above lithium salt is F - , Cl - , Br - , I - , NO3 - , N(CN)2 - , BF4 - , CF3CF2SO3 - , (CF3SO2)2N - , (FSO2)2N - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (CF3SO2)3C - , CF3(CF2)7SO3 - , CF3CO2 - , CH3CO2 - , SCN - and (CF3CF2SO2)2N - It may be at least one selected from the group consisting of, and the lithium salt is LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAl04, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2) 2. LiCl, LiI, or LiB(C2O4)2 can be used. The concentration of the lithium salt is preferably within the range of 0.1M to 4.0M, preferably 0.5M to 3.0M, and more preferably 1.0M to 2.0M. When the concentration of the lithium salt is within the above range, the electrolyte can exhibit excellent electrolyte performance because it has appropriate conductivity and viscosity, and lithium ions can move effectively. In addition to the electrolyte components, the electrolyte may further include one or more additives, such as haloalkylene carbonate compounds such as difluoroethylene carbonate, pyridine, triethylphosphite, triethanolamine, cyclic ethers, ethylene diamine, n-glyme, hexaphosphoric acid triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N,N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, or aluminum trichloride, for the purpose of improving the life characteristics of the battery, suppressing battery capacity decrease, and improving the discharge capacity of the battery. At this time, the additives may be included in an amount of 0.1 to 10.0 wt% based on the total weight of the electrolyte. cathode The above negative electrode includes a negative electrode current collector and a negative electrode active material layer positioned on the negative electrode current collector. According to one embodiment of the present invention, the negative electrode may apply a metallized film as described above as a negative electrode collector, and may include the negative electrode collector and a negative electrode active material layer disposed thereon. The above negative electrode active material layer optionally includes a binder and a conductive material together with the negative electrode active material. As the negative electrode active material, a compound capable of reversible intercalation and deintercalation of lithium may be used. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds capable of alloying with lithium such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloy, Sn alloy, or Al alloy; SiO a (0 <a<2), sno2, 바나듐 산화물, 리튬 산화물과 같이 리튬을 도프 및 탈도프할 수 있는 금속산화물; 또는 si-c 복합체 sn-c 복합체과 상기 금속질 화합물과 탄소질 재료를 포함하는 복합물 등을 들 있으며, 이들 중 어느 하나 둘 이상의 혼합물이 사용될 있다. 또한, 음극 활물질로서 금속 박막이 수도 또, 탄소재료는 저결정성 탄소 고결정성 등이 모두 탄소로는 연화탄소 (soft carbon) 경화탄소 (hard carbon)가 대표적이며, 무정형, 판상, 인편상, 구형 섬유형의 천연 흑연 인조 흑연, 키시 (kish graphite), 열분해 (pyrolytic carbon), 액정 피치계 탄소섬유 (mesophase pitch based carbon fiber), 미소구체 (meso-carbon microbeads), 액정피치 (mesophase pitches) 석유와 석탄계 코크스 (petroleum or coal tar derived cokes) 등의 고온 열처리탄소가 대표적이다.The above negative electrode active material may be included in an amount of 80 wt% to 99 wt%, 82 wt% to 99 wt%, or 84 wt% to 99 wt% based on the total weight of the negative electrode active material layer. The above binder is a component that assists in bonding between the conductive material, the active material, and the current collector, and is typically added in an amount of 0.1 wt% to 10 wt% based on the total weight of the negative electrode active material layer. Examples of such binders include polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene polymer (EPDM), sulfonated-EPDM, styrene-butadiene rubber, nitrile-butadiene rubber, fluororubber, and various copolymers thereof. The conductive agent is a component for further improving the conductivity of the negative electrode active material, and may be included in an amount of 1 wt% to 30 wt%, 1 wt% to 20 wt%, or 1 wt% to 10 wt% based on the total weight of the negative electrode active material layer. The conductive agent is not particularly limited as long as it has conductivity without causing a chemical change in the battery, and examples thereof include graphite such as natural graphite or artificial graphite; carbon black such as acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber or metal fiber; fluorinated carbon; metal powder such as aluminum or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives. The above negative electrode active material layer can be manufactured by applying and drying a negative electrode slurry composition prepared by dissolving or dispersing a negative electrode active material, and optionally a binder and a conductive material in a solvent, on a negative electrode current collector, or by casting the negative electrode slurry composition on a separate support, and then laminating the obtained film by peeling it off from the support on a negative electrode current collector. In addition, the lithium secondary battery may optionally further include a battery container that houses the electrode assembly of the positive electrode, the separator, and the negative electrode, and a sealing member that seals the battery container. In addition, since the lithium secondary battery according to the present invention stably exhibits excellent discharge capacity, output characteristics, and capacity retention rate, it is useful in portable devices such as mobile phones, laptop computers, and digital cameras, and electric vehicles such as hybrid electric vehicles (HEVs). In particular, to achieve longer battery life on a single charge, batteries need to be increased in capacity, and this requires large-area electrode technology. However, the process of increasing the electrode area can degrade electrode performance, and there are concerns about thermal runaway and heat propagation to other electrodes in the event of a fire. Accordingly, according to another embodiment of the present invention, a battery module including a plurality of the lithium secondary batteries and a battery pack including a plurality of the battery modules are provided. The above battery module refers to a battery assembly (assembly) in which a certain number of lithium secondary batteries are bundled and placed in a frame to protect them from external shocks, heat, vibration, etc. The above battery pack refers to the final form of a battery system installed in electric vehicles, etc. The above battery module or battery pack can be used as a power source for one or more medium- to large-sized devices, such as power tools; electric vehicles including electric vehicles (EVs), hybrid electric vehicles, and plug-in hybrid electric vehicles (PHEVs); or power storage systems. The battery module and battery pack according to the present invention, when including a plurality of the electrode current collectors described above, can maximize safety by thermal propagation in the event of an actual fire, thereby realizing high capacity and large area of ​​the battery. Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. Examples and Comparative Examples Example 1 An electrode current collector was manufactured by forming a first metal layer and a second metal layer by physical vapor deposition (PVD) of aluminum metal on both sides of a polyethylene terephthalate (PET) having a thickness of 6 ㎛ and containing 30 wt% of the total weight of lead oxide (PbO) having an average particle diameter of 0.5 ㎛. Example 2 An electrode current collector was manufactured by forming a first metal layer and a second metal layer by physical vapor deposition (PVD) of aluminum metal on both sides of polyethylene terephthalate (PET) having a thickness of 10 ㎛ and containing 50 wt% of the total weight of bismuth ruthenic acid (Bi2Ru2O7) having an average particle diameter of 0.5 ㎛. Example 3 An electrode current collector was manufactured in the same manner as in Example 1, except that 30 wt% of the total weight of ruthenium dioxide (RuO2) having an average particle size of 1.0 ㎛ was used instead of lead oxide (PbO) having an average particle size of 0.5 ㎛. Comparative Example 1 Aluminum metal with a thickness of 12 ㎛ was used as the electrode current collector. Comparative Example 2 An electrode current collector was manufactured by forming a first metal layer and a second metal layer by physically vapor deposition (PVD) of aluminum metal to a thickness of 1 μm on both sides of polyethylene terephthalate (PET) having a thickness of 6 μm and not including metal oxide. Comparative Example 3 An electrode current collector was manufactured in the same manner as in Example 1, except that polyethylene terephthalate (PET) having a thickness of 2 μm and aluminum metal having a thickness of 3 μm were used. Comparative Example 4 An electrode current collector was manufactured in the same manner as in Example 1, except that polyethylene terephthalate (PET) having a thickness of 40 μm and aluminum metal having a thickness of 1.5 μm were used. Comparative Example 5 An electrode current collector was manufactured in the same manner as in Example 1, except that polyethylene terephthalate (PET) having a thickness of 8 μm and aluminum metal having a thickness of 5 μm were used. Comparative Example 6 An electrode current collector was manufactured in the same manner as in Example 1, except that carbon black having an average particle size of 1.0 μm was included in an amount of 30 wt% of the total weight instead of lead oxide (PbO) having an average particle size of 0.5 μm. Comparative Example 7 An electrode current collector was manufactured in the same manner as in Example 1, except that aluminum metal powder having an average particle size of 1.0 μm was used instead of lead oxide (PbO) having an average particle size of 0.5 μm, at 30 wt% of the total weight. Experimental Example 1 The resistance characteristics and safety of lithium secondary batteries manufactured using the electrode current collectors manufactured in Examples 1 to 3 and Comparative Examples 1 to 7 were evaluated through 1) electrical resistivity, 2) heat transfer delay test, 3) nail penetration test, and 4) weldability test, and the results are shown in Table 1 below. In Table 1, the "◎" mark means very good, the "○" mark means good, the "△" mark means average, and the "X" mark means poor. Manufacturing of lithium secondary batteries A cathode slurry was prepared by mixing cathode active material (NCM65 1520), conductive agent (Li-435), and PVDF binder (KF9700, AD-c01) in a weight ratio of 96.5:1.5:2.0 in N-methylpyrrolidone. After applying the positive electrode slurry to one surface of the electrode current collector manufactured in each of Examples 1 to 3 and Comparative Examples 1 to 7, the positive electrode was manufactured by drying at 140°C and then rolling. Graphite was used as the negative active material, and a negative electrode slurry containing a binder and a conductive material was applied to copper foil and dried to manufacture a negative electrode. An electrode assembly was manufactured by interposing a separator between the positive and negative electrodes manufactured by the above-described method, and then positioning it inside a battery case, and then injecting an electrolyte into the case to manufacture a battery cell. The electrolyte was manufactured by dissolving 0.7 M LiPF6 in a mixed organic solvent of ethylene carbonate (EC): propylene carbonate (PC): ethyl methyl carbonate (EMC) = 2:1:7 by volume. Specifically, the experimental methods for 1) electrical resistivity, 2) time delay effect on thermal propagation, 3) safety from nail penetration, and 4) weldability are as follows. 1) Electrical resistivity: The surface resistance of the electrode current collectors manufactured in the above examples and comparative examples was measured using a 4-point probe device, and evaluated in 4 stages. 2) Heat propagation delay test: Five of the manufactured battery cells are assembled into a module, and heat is applied to one battery cell at a rate of 0.5°C / sec using a heating pad. The heat to adjacent cells is measured using a thermocouple to determine the degree of time delay for heat propagation, which is then evaluated in four stages. 3) Penetration test: The manufactured battery cell was penetrated at a speed of 0.1 mm / s using a sharp nail type to conduct a nail penetration test. If ignition occurred, it was evaluated as X, and if not, it was evaluated as ○. 4) Weldability test: After stacking 10 electrode current collectors manufactured in the above examples and comparative examples, welding was performed. If any of the welded electrode current collectors were separated or a pin hole with a diameter of about 3 mm or more occurred, it was evaluated as x. If no separation occurred but a crack or a diameter of less than about 3 mm occurred, it was evaluated as △. If no crack, pin hole, or separation occurred, it was evaluated as ○ or ◎. ○ and ◎ indicate different evaluations depending on the strength. Electrical resistivity, heat propagation delay test, penetration test, weldability test, Example 1, △○○○, Example 2, △○○○, Example 3, △○○○, Comparative Example 1, ◎XX, ◎, Comparative Example 2, X○○X, Comparative Example 3, ○XX○, Comparative Example 4, X◎○X, Comparative Example 5, ○XX, △, Comparative Example 6, ○○○X, Comparative Example 7, ○XX○ Referring to Table 1 above, in the case of Examples 1 to 3, it can be confirmed that the electrical resistivity was improved compared to Comparative Example 2, which used a current collector in which a resin layer was placed between metal layers as a metallized film, while also showing excellent results in heat transfer delay and penetration tests, and that the weldability was also excellent. On the other hand, in the case of Comparative Examples 1 to 7, in the case where the electrical characteristics and / or weldability were excellent, the safety evaluation results were considerably poor, and in the case where the safety was secured to some extent, the electrical characteristics and weldability were evaluated as poor. Specifically, when looking at the conventional aluminum foil such as Comparative Example 1, or Comparative Example 3 in which the metal layer is thicker than the resin layer because the thickness ratio is smaller than 1, or Comparative Example 5 in which the resin layer is thicker than the metal layer so that the thickness ratio exceeds 1 but the metal layer is thicker than 3 ㎛, and Comparative Example 7 in which metal powder is added to the resin layer, it can be confirmed that there is no improvement in terms of safety like the conventional aluminum current collector. In addition, in the case of Comparative Examples 2 and 4 in which the resin layer is too thick or does not contain a metal oxide, the resistivity characteristics are not improved, so although safety can be guaranteed, there is a problem in which the output performance suffers a great loss. [Explanation of symbols] 11: Resin layer 11a: First resin layer 11b: Second resin layer 11c: Third resin layer 12: First metal layer 13: Second metal layer 14: Metal oxide

Claims

1. A resin layer; a first metal layer disposed on one surface of the resin layer; and a second metal layer disposed on the other surface of the resin layer, The first metal layer and the second metal layer each independently have a thickness of 3.0 ㎛ or less, The thickness (T) of the first metal layer or the second metal layer M ) for the thickness of the resin layer (T R ) of the ratio (T R / T M ) is 1 to 24, The above resin layer comprises an electrode current collector comprising a metal oxide represented by the following chemical formula 1: [Chemical Formula 1] M1 x M2 y O z In the above chemical formula 1, M1 is one or more post-transition metals selected from the group consisting of Al, Ga, In, Sn, Pb, and Bi, M2 is one or more transition metals selected from the group consisting of Ti, Zr, Nb, Ru, Hf, Cr, Mo, Ni, Co, V, Y, and Zn, 0≤x≤4, 0≤y≤4, and 1≤z≤8, x and y cannot be 0 at the same time, and x, y, and z are defined in consideration of the oxidation numbers of M1 and M2 and the oxidation number of oxygen.

2. In paragraph 1, An electrode current collector, wherein the metal oxide comprises at least one selected from the group consisting of lead oxide (PbO), ruthenium dioxide (RuO2), alumina (Al2O3), zirconia (ZrO2), bismuth ruthenic acid (Bi2Ru2O7), and bismuth iridic acid (Bi2Ir2O7).

3. In paragraph 1, An electrode current collector, wherein the metal oxide is present in an amount of 10 wt% to 60 wt% based on the total weight of the resin layer.

4. In paragraph 1, An electrode current collector, wherein the above metal oxide has an average particle diameter of 0.5 ㎛ to 2.0 ㎛.

5. In paragraph 1, An electrode current collector, wherein the resin layer further comprises at least one selected from the group consisting of polyester resin, epoxy resin, phenol resin, melamine resin, urethane resin, silicone resin, vinyl acetate resin, rubber resin, acrylic resin, and polyetherurethane resin.

6. In paragraph 1, An electrode current collector, wherein the first metal layer and the second metal layer each independently include at least one selected from the group consisting of copper, stainless steel, aluminum, nickel, titanium, heat-treated carbon, and aluminum-cadmium alloy.

7. In paragraph 1, An electrode current collector, wherein the resin layer has a thickness of 2 ㎛ to 12 ㎛.

8. In paragraph 1, An electrode current collector, wherein the first metal layer and the second metal layer each independently have a thickness of 0.2 ㎛ to 2.5 ㎛.

9. In paragraph 1, An electrode current collector, wherein the above resin layer has a thickness deviation of 10% or less.

10. In paragraph 1, An electrode current collector, wherein the first metal layer and the second metal layer each independently have a thickness deviation of 5% or less.

11. An electrode assembly having a structure in which a plurality of electrodes and a plurality of separators are alternately stacked, The above electrode includes an electrode current collector and an electrode active material layer disposed on the electrode current collector, A lithium secondary battery, wherein at least one of the plurality of electrode current collectors is an electrode current collector according to claim 1.

12. A battery module comprising a plurality of lithium secondary batteries described in Article 11.

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