• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
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  • 优先权
    • 专利摘要:
    secondary battery including high-capacity negative electrode and manufacturing method. described are a secondary battery comprising a negative electrode composed of two or more negative electrode plates and a method of manufacturing the secondary battery, wherein each of the negative electrode plates includes a layer of lithium by-product formed through a pre-reaction. litigation on a negative electrode current collector coated with a negative electrode active material, in which a layer of inorganic substance is formed on a negative electrode tongue that is extended from one end on one side of the negative electrode current collector and is composed of an uncoated portion of active material not coated with the active material of the negative electrode and the negative electrode tabs of the negative electrode plates are electrically connected with a negative electrode to form a negative electrode terminal.
    公开号:BR112017005881B1
    申请号:R112017005881-2
    申请日:2016-01-28
    公开日:2021-07-20
    发明作者:Kyoung Ho Kim；Chae Ah Kim；Jooyong Song；Hye Youn Lee；Hoe Jin Hah
    申请人:Lg Chem, Ltd.；
    IPC主号:
    专利说明:

    [TECHNICAL FIELD]
    [0001] This application claims the benefit of Korean Patent Application No. 10-2015-0015891, filed on February 2, 2015, with the Korean Intellectual Property Department, the disclosure of which is incorporated herein by reference. in its entirety.
    [0002] The present invention relates to a secondary battery that includes a high-capacity negative electrode and a method of manufacturing the same. More particularly, the present invention relates to a secondary battery that includes a negative electrode that includes a pre-lithiated negative electrode current collector and a negative electrode tongue, on which a layer of inorganic substance is formed, to provide a high capacity and, consequently, marked service life and speed characteristics and increased production efficiency, and a manufacturing method of the same. [PREVIOUS TECHNIQUE]
    [0003] As the technological development of various devices and the demand for them continue to increase, the demand for secondary batteries as power sources is increasing rapidly. Among these secondary batteries, lithium secondary batteries that have high energy density and voltage and exhibit a long life and low rate of self-discharge are commercially available and widely used.
    [0004] In these secondary lithium batteries, a lithium-containing cobalt oxide (LiCoO2) with a layered crystal structure, LiMnO2 with a layered crystal structure, a lithium-containing manganese oxide such as LiMn2O4 with a spinel crystal structure, or a lithium-containing nickel oxide such as LiNiO2 is generally used as an electrode positive active material. In addition, a carbon-based material is mainly used as a carbon-negative active material. Recently, the demand for high-capacity secondary batteries is increasing, so the use of a silicon-based material or a mixture including a silicon oxide-based material with an effective capacity of 10 times or greater than that of a material carbon-based is under consideration.
    [0005] However, lithium secondary batteries have several problems. For example, some secondary lithium batteries have problems related to characteristics in the manufacture and operation of a negative electrode.
    [0006] For example, in an initial charge and discharge process (activation process) of a carbon-based negative electrode active material, a solid electrolyte interface (SEI) layer is formed on a surface of the active material of the negative electrode and, consequently, the initial irreversibility is induced. Furthermore, a SEI layer is folded in a continuous charging and discharging process and an electrolyte solution is depleted in a regeneration process, whereby the battery capacity is reduced.
    [0007] Furthermore, in the case of a silicon-based material, a high capacity is displayed, but a volumetric expansion ratio is 300% or more with increasing cycle count. Consequently, the resistance and side reaction of an electrolyte solution can be increased, and thus, problems due to formation of SEI layers, such as damage to the electrode structure, can be intensified.
    [0008] Since a silicon oxide-based material has a lower volumetric expansion rate and superior fatigue life characteristics compared to a silicon-based material, its application can be considered. However, silicon oxide based material also has problems such as formation of SEI layers during loading and a high frequency of initial irreversibility to Li2O due to oxygen present in an active material.
    [0009] In order to solve such problem, the investigation on a method to alter the oxygen, which is present in a material based on silicon oxide, causing an irreversible high capacity in a lithium oxide through the pre-lithiation of the material Silicon oxide-based is actively underway. Such method can increase the useful life, reducing the initial irreversibility of the material based on silicon oxide. However, when this method is used, large amounts of by-products are generated in a process where a silicon oxide-based material is prelithiated with a lithium source and most of the lithium oxide is generated on a surface of the silicon oxide-based material. Therefore, there is a limitation in reducing irreversibility.
    [0010] Recently, to solve such problems, attempts have been made to completely decrease the initial irreversibility and thus improve the characteristics of the cycle by feeding a negative electrode in a solution containing a lithium source, applying current to the negative electrode and, consequently, allowing the pre-litigation reaction. However, when a lithium layer is formed on the negative electrode by applying current, a lithium by-product is also formed on an uncoated portion of the negative electrode active material that has not been coated with a negative electrode active material. Consequently, it is difficult to solder the active material uncoated portion of the negative electrode to a negative electrode conductor, so it is impossible to manufacture a cell.
    [0011] Therefore, there is an urgent need for technology to manufacture a secondary battery with high energy density while addressing such problems. [DISCLOSURE] [TECHNICAL PROBLEM]
    [0012] Therefore, the present invention was made to solve the above technical problems and others that have yet to be solved.
    [0013] It is an objective of the present invention to provide a secondary battery with improved life and speed characteristics by using a high-capacity negative electrode active material, using a pre-lithiated negative electrode current collector to minimize an irreversibility of according to the application of the active material of negative electrode, and a manufacturing method of the secondary battery.
    [0014] It is another objective of the present invention to provide a secondary battery with greatly increased production efficiency, facilitating the connection of a negative electrode tongue to a negative electrode through the application of the negative electrode tongue in which a layer of inorganic substance is formed and a method of manufacturing the secondary battery. [TECHNICAL SOLUTION]
    [0015] According to one aspect of the present invention, the above and other objectives can be achieved by providing a secondary battery, including a negative electrode composed of two or more negative electrode plates, in which each of the electrode plates negative includes a layer of lithium by-product formed through a pre-lithiation reaction on a negative electrode current collector coated with a negative electrode active material, wherein an inorganic substance layer is formed on a negative electrode tongue that is extending from one end on one side of the negative electrode current collector and is composed of a portion of uncoated active material not coated with the negative electrode active material and the negative electrode tabs of the negative electrode plates are electrically connected to a negative electrode to form a negative electrode terminal.
    [0016] As described above, when using a high-capacity negative electrode active material, the irreversibility of a negative electrode can be enhanced due to the formation of a SEI layer. In order to solve this problem, irreversibility can be avoided by pre-inserting lithium and thus allowing for pre-lithiation. However, in this case, a layer of lithium by-product is also formed on a surface of a negative electrode tab that is not coated with a negative electrode active material, thus preventing the connection of the negative electrode tabs to an electrode. negative. Consequently, it is impossible to manufacture a secondary battery.
    [0017] Consequently, the inventors of the present invention have confirmed that when a layer of inorganic substance is previously formed on a negative electrode tongue of a negative electrode plate, the resistance of a portion coated with the inorganic substance is increased and thus the current does not flow well in position By pre-lithiation even in a lithium-based solvent. As a result, the inventors of the present invention have confirmed that lithium is not easily deposited and thus a layer of lithium by-product does not form.
    [0018] Therefore, the present invention can provide a secondary battery with increased life and speed characteristics, as well as greater production efficiency, by previously forming a layer of inorganic substance on the negative electrode tongue of the negative electrode plate and thus prelitting only the negative electrode portion coated with the active material of the negative electrode of the negative electrode plate, thus increasing the coupling force between the negative electrode tabs and the negative electrode conductor.
    [0019] In the present invention, the active material of the negative electrode may include, as a silicon-based material, one or more selected from the group consisting of, for example, silicon (Si), a silicon alloy, SiB4 , SiB6, Mg2Si, Ni2Si, TiSi2, MoSi2, CoSi2, NiSi2, CaSi2, CrSi2, Cu5Si, FeSi2, MnSi2, NbSi2, TaSi2, VSi2, WSi2, ZnSi2, SiC, Si3N4, Si2N2O where < 0.5 Siv 1,2 and LiSiO. The active material of the negative electrode may particularly include SiOv where 0.5<v<1,2, more particularly SiO which has the lowest volumetric expansion among silicon-based materials and superior cycle characteristics.
    [0020] When this SiO is used as an electrode negative active material, the irreversibility increases due to the oxygen present in the active material and the capacity can be rapidly decreased with increasing cycle count. However, the present invention can reduce irreversibility by generating lithium oxide, which is formed by previous reaction of oxygen and lithium, in the active material through pre-lithiation and capacity reduction with increased cycle count.
    [0021] The active material of the negative electrode may further include, with the exception of the silicon-based materials mentioned above, a carbon-based material.
    [0022] The carbon-based material can be any carbon-based material available in the art. The carbon-based material can be one or more selected from the group consisting of, for example, graphite, artificial graphite, mesocarbon microbubble (MCMB), carbon fiber, carbon black, acetylene black and Ketjen black . Particularly, the carbon-based material can be graphite.
    [0023] When the active material of the negative electrode includes a silicon-based material and a carbon-based material, the silicon-based material may be included in an amount of 80% by weight or less, particularly 50% by weight or less based on the total weight of active material of the negative electrode. More particularly, the silicon-based material can be included in an amount of 30% by weight or less. More particularly, the silicon-based material can be included in an amount of 15% by weight or less. When the silicon-based material is mixed with the carbon-based material, and in this case the amount of the silicon-based material is too small, it is impossible to anticipate the desired capacity increase. When the amount of silicon-based material is too large, its volumetric expansion can be intensified compared to carbon-based material.
    [0024] In the present invention, the lithium by-product formed in the current collector of the negative electrode coated with the active material of the negative electrode includes lithium. For example, the lithium by-product can be one or more selected from the group consisting of lithium metal such as Li, lithium oxide such as Li2O or Li2O, lithium chloride such as LiCl and an inorganic compound such as LiCl4 . In particular, the lithium by-product can be Li2O.
    [0025] Although the thickness of the lithium by-product layer depends on a pre-lithiation condition, the thickness can be from 0.01 µm to 1 µm, particularly 0.05 µm to 0.5 µm, more particularly 0.1 µm to 0.3 µm.
    [0026] When the thickness of the lithium by-product layer is less than 0.01 µm, the negative electrode is hardly prelithiated. Consequently, the irreversibility of the active material of the negative electrode may not be sufficiently prevented and thus the desired effects may not be obtained. When the thickness of the lithium by-product layer is greater than 1 µm, the internal resistance of the negative electrode is unexpectedly increased.
    [0027] In addition, an inorganic substance formed in the negative electrode tongue composed of the uncoated portion of active material, which is not coated with the active material of the negative electrode, may be one or more selected from the group consisting of SiO2 , TiO2, Al2O3, ZO2, MgO, CaO, ZnO, Y2O3, Pb(Zr,Ti)O3(PZT), Pb1-xLaxZr1- yTiyO3 (PLZT) where 0<x<1 and 0<y<1, Pb(Mg1 /3Nb2/3)O3-PbTiO3(PMN-PT), BaTiO3, hafnium oxide (HfO2), SrTiO3 and a mixture of two or more of these.
    [0028] As needed, in a range within which the effects of the present invention are not diminished, the inorganic substance may be a mixture including one or more selected polymer resins, e.g. polyethylene, polypropylene, poly(ether imide) , polyacetal, polysulfone, polyetheretherketone, polyether, polyamide, an ethylene-vinyl acetate copolymer, polystyrene, polytetrafluoroethylene, polysiloxane and polyimide, a copolymer and a mixture thereof.
    [0029] The thickness of the inorganic substance layer can be from 1 μm to 10 μm, particularly from 10 μm to 5 μm, more particularly from 100 μm to 2 μm.
    [0030] When the thickness of the inorganic substance layer is less than 1 nm, the amount of an inorganic substance is not sufficient and thus the lithium by-product layer can be formed on the negative electrode tongue during pre-lithiation. When the thickness of the inorganic substance layer is more than 10 µm, it is difficult to weld between the negative electrode tongues and the negative electrode of the electrode, and thus, it can be difficult to get their electrical connection.
    [0031] The layer of inorganic substance formed on the negative electrode tab constituted by the uncoated portion of active material can be particularly formed on the entire negative electrode tab.
    [0032] The present invention provides a method for manufacturing the secondary battery, the method including: (a) coating the active material of the negative electrode in the portion of the negative electrode current collector, with the exception of the portion corresponding to the tongue of the negative electrode, of the foil and then coat the negative electrode tongue composed of the uncoated portion of active material that is not coated with the active material of the negative electrode with the inorganic substance; (b) pre-lithiation by feeding the fabricated metal sheet by coating (a) in the lithium-based solvent and then applying current to it; (c) cutting the fabricated sheet metal through the pre-litigation (b) into the shape of the negative electrode plate which includes the negative electrode current collector portion and the negative electrode tongue; and (d) form the negative electrode terminal by stacking two or more plates of negative electrodes fabricated by cutting (c) and then electrically connecting the negative electrode plugs to the negative electrode conductor.
    [0033] In coating (a), the sheet metal can be extended in width and length directions so as to cut a plurality of negative electrodes. The sheet metal can be made, for example, of stainless steel, aluminum, nickel, titanium, sintered carbon or copper or stainless steel surface treated with carbon, nickel, titanium or silver or an aluminum-cadmium alloy. Particularly, sheet metal can be made of copper.
    [0034] Pre-lithiation (b) can be carried out, for example, by placing the metal sheet between two opposite rollers and allowing this metal sheet to pass through a chamber containing a lithium-based solvent.
    [0035] The lithium-based solvent can be one or a mixture of two or more selected from the group consisting of LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, CF3SO2)2NLi, Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH and Li3PO4-Li2S. However, the present invention is not limited to these materials.
    [0036] Pre-lithiation can be carried out by applying a current of 10 mA to 10A for 0.1 hours to 12 hours, particularly a current of 100 mA to 5A for 1 hour to 10 hours.
    [0037] The actual levels and time conditions of the pre-litigation are optimal conditions to carry out the desired pre-litigation. When these conditions are outside the ranges, pre-lithiation is hardly carried out, or the thickness of the lithium by-product layer increases. Consequently, strength increases and the time required for pre-litigation is prolonged, thus decreasing productivity.
    [0038] Even when pre-lithiation (b) is performed in a lithium-based solvent, a layer of lithium by-product is not easily formed because current does not flow easily due to the high resistance of the negative electrode tongue coated with the inorganic substance in the coating (a).
    [0039] Therefore, in section (c), the negative electrode current collector portion may include the lithium by-product layer formed through the pre-lithiation.
    [0040] Furthermore, a stabilization process of the sheet metal at 30°C to 100°C for 6 hours to 12 hours, particularly at 40°C to 100°C for 6 hours to 10 hours can be additionally included among the pre-litigation (b) and the court (c).
    [0041] When a stabilization process is further carried out under the conditions after pre-lithiation of the sheet metal, the lithium oxide layer can be sufficiently formed on the negative electrode current collector, which is coated with the active material of the electrode negative, of the metallic sheet.
    [0042] In formation (d), since the inorganic substance layer is previously formed on the negative electrode tongue that is not coated with the active material of the negative electrode, the generation of the lithium by-product layer due to pre-lithiation can be avoided. Consequently, the connection of the tabs of the negative electrode to the conductor of the negative electrode can easily be carried out by welding.
    [0043] In general, laser welding is performed non-uniformly, depending on a surface state, and resistance welding provides a high bond strength, but has a large deformation in a bonded part, due to exposure to high temperatures. Consequently, since welding is carried out using frictional heat in the present invention, surface deformation of the bonded part is decreased and ultrasonic soldering, which allows for uniform soldering irrespective of a state of the bonded surface, can be carried out.
    [0044] The principle of bonding through this ultrasonic welding is as follows. Welding is performed quickly while vibrating energy is converted to thermal energy due to friction at the interfaces between the negative electrode tongues and between a negative electrode tongue and a negative electrode, using high frequency vibration generated by ultrasonic waves of about 20 kHz. The surfaces of the electrode tongues, which are recently exposed by partial plastic deformation of the interface coating layers, are adhered together by friction, which is concomitant with vibration. Furthermore, diffusion and recrystallization of atoms are promoted by the partial increase in temperature due to frictional heat, and thus, a solid part welded under pressure can be formed.
    [0045] Furthermore, even when the inorganic substance layer is formed on the negative electrode tongue, the negative electrode tongue can be easily welded with the negative electrode conductor due to the frictional heat generated by the application of ultrasonic waves.
    [0046] Such secondary battery may be a lithium battery as an embodiment, but the present invention is not limited thereto.
    [0047] The lithium secondary battery includes a positive electrode, which is prepared by coating a mixture of a positive electrode active material, a conductive material and a binder in a positive electrode current collector and drying and pressure collector positive coated electrode current and a negative electrode prepared using the same method as used to fabricate the positive electrode. In this case, the mixture may further include a filler as desired.
    [0048] The positive electrode current collector is generally manufactured in a thickness of 3 to 500 µm. The positive electrode current collector is not particularly limited as long as it does not cause chemical changes in the manufactured lithium secondary battery and has high conductivity. For example, the positive electrode current collector can be made of stainless steel, aluminum, nickel, titanium, sintered carbon, aluminum, or stainless steel surface treated with carbon, nickel, titanium, or silver. The positive electrode current collector may have fine irregularities on a surface to increase the adhesion between the positive electrode active material and the positive electrode current collector. In addition, the positive electrode current collector can be used in any of several forms including films, sheets, sheets, meshes, porous structures, foams and non-woven fabrics.
    [0049] The secondary lithium battery may include, as active material of the positive electrode, lithium and nickel oxides (LiNiO2, lithium and manganese oxides, such as compounds of Formula Lii+xMn2-xO4 where 0<x<0.33 , LiMnO3, LiMn2O3 and LiMnO2; (Li2CuO2), vanadium oxides such as LiV3O8, LiV3O4, V2O5 and Cu2V2O7, Ni-type nickel-lithium oxides of the LiNi1-xMxO2 type where M = Co, Mn, Al, Cu , Mg, B or Ga and 0.01<x<0.3; LiMn2-xMxO2 lithium manganese compound oxides where M = Co, Ni, Fe, Cr, Zn or Ta and 0.01<x <0.1), or Formula Li2Mn3MO8 where M = Fe, Co, Ni, Cu or Zn; LiNixMn2-xO4 Lithium Manganese Compound Oxides of the spinel structure of Formula where x = 0.01 to 0.6; LiMn2O4 in which some of the Li atoms are replaced by alkaline earth metal ions; Disulfide compounds; Fe2(MoO4)3; and the like.
    [0050] The conductive material is generally added in an amount of 1 to 50% by weight relative to the total weight of a mixture, including an active electrode positive material. This conductive material is not specifically limited as long as it does not cause chemical changes in the manufactured battery and has conductivity. For example, graphite such as natural or artificial graphite; carbon black, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black and thermal black; conductive fibers such as carbon fibers and metal fibers; metallic powders such as carbon fluoride powder, aluminum powder and nickel powder; conductive wires such as zinc oxide wires and potassium titanate wires; conductive metal oxides such as titanium oxide; conductive materials such as polyphenylene derivatives; and the like can be used.
    [0051] The binder is a component that assists in the connection between an active material and the conductive material and in the connection of the active material to a current collector. The binder is typically added in an amount of 1 to 50% by weight based on the total weight of the mixture including the active material of the positive electrode. Examples of the binder include, but are not limited to, polyvinylidene fluoride, polyvinyl alcohols, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer, EPDM, sulfonated EPDM , styrene butylene rubber, fluorine rubber and various copolymers.
    [0052] The filler is optionally used as a component to inhibit expansion of the positive electrode. The filler material is not particularly limited as long as it is a fibrous material that does not cause chemical changes in the manufactured battery. Examples of the filler material include olefin-based polymers such as polyethylene and polypropylene; and fibrous materials such as fiberglass and carbon fiber.
    [0053] The negative electrode current collector is typically manufactured with a thickness of 3 to 500 µm.
    [0054] The lithium secondary battery may have a structure in which an electrode set, which includes a positive electrode, a negative electrode and a separator disposed between the positive electrode and the negative electrode, is impregnated with an electrolyte containing lithium salts .
    [0055] The separator is arranged between the positive electrode and the negative electrode and, as a separator, a thin insulating film with high permeability to ions and high mechanical strength is used. The separator generally has a pore diameter of 0.01 to 10 µm and a thickness of 5 to 300 µm. As a separator, for example, non-woven sheets or fabrics made of an olefin-based polymer such as polypropylene are used; or glass fibers or polyethylene, which have chemical resistance and hydrophobicity. When a solid electrolyte such as a polymer or the like is used as an electrolyte, the solid electrolyte can also serve as a separator.
    [0056] The electrolyte solution containing lithium salts consists of a non-aqueous solvent and a lithium salt. The lithium salt is a material that is readily soluble in the non-aqueous electrolyte and its examples include, but are not limited to LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, (CF3SO2)2NLi, lithium chloroborane, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imides.
    [0057] The non-aqueous solvent is not specifically limited as long as it is known in the art and may be one or more selected from the group consisting, for example, of ethylene carbonate (EC), propylene carbonate (PC), carbonate of butylene (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), methyl propionate (MP) and ethyl propionate (EP).
    [0058] Furthermore, to improve the charge/discharge characteristics and flame retardancy, for example, pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric triamide, nitrobenzene derivatives, sulfur dyes, quinone imine, N-substituted oxazolidinone, N,N-substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salts, pyrrole, 2-methoxy ethanol, aluminum trichloride or the like can be added to the electrolyte. If necessary, in order to confer non-combustibility, the electrolyte may further include halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride. Furthermore, in order to improve the high temperature storage characteristics, the non-aqueous electrolyte may further include carbon dioxide gas, and propyl sultone (PRS) and the like may be additionally included.
    [0059] In a preferred embodiment, the non-aqueous lithium salt-containing electrolyte can be prepared by adding a lithium salt such as LiPF6, LiClO4, LiBF4, LiN(SO2CF3)2 or the like to a high dielectric solvent.
    [0060] The present invention also provides a device that includes the secondary battery as a power source. The device can be selected from mobile phones, laptop computers, smartphones, tablet PCs, smart pads, netbook computers, light electric vehicles (LEVs), light electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, energy storage devices and the like.
    [0061] The structures of these devices and the methods of fabrication of the devices are known in the art and thus their detailed descriptions are omitted. [BRIEF DESCRIPTION OF THE DRAWINGS]
    [0062] The foregoing and other objectives, features and other advantages of the present invention will be more clearly understood from the following detailed description, taken in conjunction with the accompanying drawings, in which:
    [0063] FIG. 1 is a graph showing the lifetime characteristics of lithium batteries according to Example 1 and Comparative Examples 1 and 2, measured in Experimental Example 2. [MODE FOR INVENTION]
    [0064] Now, the present invention will be described in more detail with reference to the following examples. These examples are provided for illustration of the present invention only and are not to be construed as limiting the scope and spirit of the present invention. <Example 1>1-1) Negative Electrode Plate Fabrication
    [0065] A negative electrode suspension, which was prepared by adding 92% by weight of a negative electrode active material including SiO and graphite in a weight ratio of 30:70, 3% by weight of Super-P as material conductor; 3.5 wt% SBR as binder and 1.5 wt% CMC as thickener for H2O as solvent was coated onto a portion of negative electrode current collector, with the exception of a portion corresponding to an electrode tongue negative, of a copper sheet at a thickness of 50 µm, followed by pressing. Subsequently, the negative electrode tongue, which was composed of the part of uncoated active material that was not coated with the negative electrode mixture, was coated with Al2O3 to a thickness of 0.2 µm.
    [0066] This resulting copper foil was introduced into a non-aqueous EC/EMC based electrolyte solution containing a LiCl salt and a 1M LiPF6 lithium salt and then a current of 100 mA was applied for one hour, whereby the copper foil was pre-lithiated as much as an irreversible amount.
    [0067] Subsequently, the metal sheet was cut into the shape of a negative electrode plate including the coated negative electrode portion and the negative electrode tongue. 1-2. Positive Electrode Plate Fabrication
    [0068] Li(Ni0.8Mn0.1Co0.1)O2 was used as the active material of a positive electrode. 94 wt% Li (Ni0.8Mn0.1Co0.1) O2, 3.5 wt% Super-P as conductive material and 2.5 wt% PVdF as binder were added to NMP as a solvent to prepare a suspension of positive electrodes. The prepared positive electrode paste was coated onto an aluminum foil to a thickness of 80 µm, followed by pressing and drying. As a result, a positive electrode plate was manufactured. 1-3. Lithium battery manufacturing
    [0069] A porous separator (CelgardTM) was disposed between the fabricated positive electrode plate and the negative electrode plate. The positive electrode tabs and the negative electrode tabs were collected and arranged, and then subjected to ultrasonic welding to be respectively connected to a positive electrode and a negative electrode. Subsequently, a non-aqueous EC/EMC based electrolyte solution containing 1 M LiPF6 was added, thereby producing a lithium battery. <Comparative Example 1>
    [0070] A lithium battery was manufactured in the same manner as in Example 1, except that an uncoated active material portion of a negative electrode was not coated with an inorganic substance when manufacturing a negative electrode plate. <Comparative Example 2>
    [0071] A lithium battery was manufactured in the same way as in Example 1, except that the pre-lithiation reaction was not performed after manufacturing a negative electrode plate. <Experimental Example 1>
    [0072] The rating characteristics of lithium secondary batteries manufactured according to Example 1 and Comparative Examples 1 and 2 were measured. To measure the rate characteristics, the charge/discharge was carried out at 25°C under a voltage of 2.5 V at 4.3 V. In particular, the charge was carried out to 67.5 mA at a current of 0.1 C constant current/constant voltage (DC / CV) and the discharge was carried out under a condition of 2.5 V cut in a 0.1 C, 0.5 C, and 1 C constant current (DC) discharge manner. The discharge efficiencies of 0.5 C and 1 C with respect to the discharge capacity of 0.1 C are summarized in Table 1. <Table 1>


    [0073] As shown in Table 1, it can be confirmed that the battery according to Example 1, in which the negative electrode portion of uncoated active material has been coated with the inorganic and pre-lithiated substance, has a speed performance superior to the battery according to Comparative Example 1, in which the negative electrode portion of uncoated active material was not coated with the inorganic substance and was pre-lit.
    [0074] This is because, when the negative electrode portion of the uncoated active material is not coated with the inorganic substance, the negative electrode portion of the uncoated active material is not welded with the negative electrode conductor due to lithium by-products generated during pre-litigation or rate performance is deteriorated due to the high contact resistance with the negative electrode conductor. <Experimental Example 2>
    [0075] The lifetime characteristics of lithium secondary batteries manufactured in accordance with Example 1 and Comparative Examples 1 and 2 were measured. In order to measure the lifetime characteristics, charging was carried out up to 67.5 mA at 25 °C in a constant current/constant voltage (DC/CV) load manner of 0.5 C and 4.3 V. Discharge in constant current, under a cut-off condition of 0.5 C and 2.5 V, was performed 100 times. The results are summarized in FIGURE 1.
    [0076] As illustrated in FIGURE 1, it can be confirmed that the battery of Example 1 manufactured by coating the negative electrode portion of uncoated active material with the inorganic substance and pre-lithiation has a longer life, compared to the battery of the Comparative Example 1, in which the negative electrode portion not coated with active material was not, coated with the inorganic substance and was prelithiated, and the battery of Comparative Example 2, where the negative electrode was not prelithiated.
    [0077] This is because the battery of Comparative Example 1, in which the negative electrode portion of uncoated active material was not coated with the inorganic substance, has high resistance in the negative electrode conductor of the electrode and decreased durability due to the reaction side of lithium by-products. Furthermore, this is because, in the case of the battery of Comparative Example 2 where the negative electrode was not pre-lithiated, Li is heavily consumed due to the high irreversible capacity and large volumetric expansion, and thus the useful life of the cycle is diminished. [INDUSTRIAL APPLICABILITY]
    [0078] Since a secondary battery according to the present invention can minimize irreversibility through the pre-lithiation reaction using a high-capacity negative electrode active material, its lifetime and speed characteristics can be improved.
    [0079] Furthermore, since an inorganic substance layer is previously formed on a negative electrode tongue and then the pre-lithiation reaction is carried out in a lithium-based solvent, a lithium by-product layer cannot be formed on the negative electrode tongue. Consequently, the negative electrode tabs can be easily connected to a negative electrode and thus the production efficiency can be increased.
    [0080] While preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various modifications, additions and substitutions are possible without departing from the scope and scope of the invention as described in the appended claims.
    权利要求:
    Claims (14)
    [0001]
    1. Secondary battery comprising a negative electrode composed of two or more plates of negative electrodes, each of the plates of negative electrodes comprising a layer of lithium by-product formed through a pre-lithiation reaction in a negative electrode current collector coated with a negative electrode active material; wherein a layer of inorganic substance is pre-formed over an entire negative electrode tongue that extends from one end on one side of the negative electrode current collector and is composed of an uncoated portion of active material not coated with active material of negative electrode, and the negative electrode tabs of the negative electrode plates are electrically connected to a negative electrode to form a negative electrode terminal characterized in that the inorganic substance is one or more selected from the group consisting of SiO2, TiO2, Al2O3, ZrO2, SnO2, CeO2, MgO, CaO, ZnO, Y2O3, Pb(Zr,Ti)O3(PZT), Pb1-xLaxZr1-yTiyO3 (PLZT) where 0<x<1 and 0<y<1, Pb( Mg1/3Nb2/3)O3-PbTiO3(PMN-PT), BaTiO3, Hafnium Oxide (HfO2), SrTiO3 and a mixture of two or more of these.
    [0002]
    2. Secondary battery according to claim 1, characterized in that the active material of the negative electrode is one or more selected from the group consisting of silicon (Si), a silicon alloy, SiB4, SiB6, Mg2Si, Ni2Si, TiSi2 , MoSi2, CoSi2, NiSi2, CaSi2, CrSi2, Cu5Si, FeSi2, MnSi2, NbSi2, TaSi2, VSi2, WSi2, ZnSi2, SiC, Si3N4, Si2N2O, SiOv, where 0.5<v<1.2 and LiSiO.
    [0003]
    3. Secondary battery according to claim 1, characterized in that the active material of the negative electrode comprises SiOv in which 0.5<v<1.2.
    [0004]
    4. Secondary battery according to claim 1, characterized in that the lithium by-products are one or more selected from the group consisting of Li, Li2O, Li2CO3, LiCl and LiClO4.
    [0005]
    5. Secondary battery according to claim 1, characterized in that a thickness of the lithium by-product layer is from 0.01 µm to 1 µm.
    [0006]
    6. Secondary battery according to claim 1, characterized in that a thickness of the inorganic substance layer is from 1 nm to 10 μm.
    [0007]
    7. Method for manufacturing the secondary battery as defined in claim 1, the method characterized by comprising the steps of: coating a negative electrode active material on a negative electrode current collector portion, except for a portion corresponding to a tongue negative electrode, a sheet of metal, and then coating the negative electrode tab composed of the portion of uncoated active material that is not coated with the active material of the negative electrode with an inorganic substance; pre-lithiate by feeding the fabricated sheet metal by coating it in a lithium-based solvent and then applying current to it; cutting the sheet metal fabricated through the pre-litigation into a form of a negative electrode plate comprising the negative electrode current collector portion and the negative electrode tongue; and form a negative electrode terminal by stacking two or more fabricated negative electrode plates by cutting and then electrically coupling the negative electrode tabs with a negative electrode conductor.
    [0008]
    8. Method according to claim 7, characterized in that, in the pre-lithiation step, the lithium-based solvent is one or more selected from the group consisting of LiCl, LiBr, LiI, LiClO4, LiBF4, LiB10Cl10 , LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiSiO3, Li4-Li2Ni LiOH and Li3PO4-Li2S-SiS2.
    [0009]
    Method according to claim 8, characterized in that, in the pre-litigation step, a current of 10 mA at 10 A is applied.
    [0010]
    Method according to claim 7, characterized in that, in the pre-lithiation step, the current is applied for 0.1 hours to 12 hours.
    [0011]
    11. Method according to claim 7, characterized in that the negative electrode current collector portion of the cutting step comprises lithium by-product layer formed through the pre-lithiation reaction.
    [0012]
    Method according to claim 7, characterized in that a process of stabilizing the metal sheet at 30°C to 100°C for 6 hours to 12 hours is further comprised between the steps of pre-lithiation and cutting.
    [0013]
    13. Method according to claim 7, characterized in that, in the forming step, the connection of the negative electrode tabs to the negative electrode conductor is carried out by welding.
    [0014]
    14. Method according to claim 13, characterized in that the welding is ultrasonic welding.
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    同族专利:
    公开号 | 公开日
    CN106716682A|2017-05-24|
    US20170338480A1|2017-11-23|
    EP3179544A1|2017-06-14|
    US10581073B2|2020-03-03|
    BR112017005881A2|2018-06-26|
    JP2018503932A|2018-02-08|
    TWI630751B|2018-07-21|
    EP3179544B1|2019-12-25|
    WO2016126046A1|2016-08-11|
    PL3179544T3|2020-06-29|
    KR101783447B1|2017-10-23|
    JP6604635B2|2019-11-13|
    CN106716682B|2019-12-03|
    TW201703323A|2017-01-16|
    KR20160094652A|2016-08-10|
    EP3179544A4|2018-01-17|
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    法律状态:
    2018-08-07| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2020-02-04| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2021-06-15| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-07-20| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 28/01/2016, OBSERVADAS AS CONDICOES LEGAIS. |
    2021-09-14| B16D| Grant of patent or certificate of addition of invention cancelled|Free format text: ANULADA A PUBLICACAO CODIGO 16.1 NA RPI NO 2637 DE 20/07/2021 POR TER SIDO INDEVIDA. |
    优先权:
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    KR1020150015891A|KR101783447B1|2015-02-02|2015-02-02|Secondary Battery Comprising Anode with High Capacity and Manufacturing Method thereof|
    KR10-2015-0015891|2015-02-02|
    PCT/KR2016/000917|WO2016126046A1|2015-02-02|2016-01-28|Secondary battery including high-capacity anode and manufacturing method therefor|
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