KR20140082262A - Anode For Secondary Battery, A Manufacturing Method of The Same And Secondary Battery Having The Same - Google Patents

Abstract

The present invention relates to an anode material for a secondary battery, including: copper; a copper-metal-based anode material alloy; and a metal-based anode material. From the central portion of the anode toward the outer surface, a continuous concentration gradient is formed in the following order of the copper, copper-metal-based anode material, and metal-based anode material. The anode material is seceded from an anode collector to alleviate a problem of lifetime degradation.

Description

[0001] The present invention relates to a negative electrode for a secondary battery, a method for manufacturing the same, and a secondary battery having the same.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative electrode suitable for a secondary battery and a secondary battery having the negative electrode, and more particularly to a negative electrode for a secondary battery which prevents the separation between the negative electrode active material and the wire-

A secondary battery is a device that converts external electrical energy into a form of chemical energy, stores it, and generates electricity when it is needed. The term "rechargeable battery" also means that the battery can be recharged several times. Common secondary batteries include lead acid batteries, NiCd batteries, NiMH batteries, Li-ion batteries, and Li-ion polymer batteries. Secondary batteries provide both economic and environmental advantages over single-use primary batteries.

Secondary cells are currently used for low power applications. Such as a device that assists the starting of a vehicle, a portable device, a tool, and an uninterruptible power supply. Background Art [0002] Recent developments in wireless communication technology have led to the popularization of portable devices and the tendency to wirelessize many types of conventional devices, and demand for secondary batteries is exploding. In addition, hybrid vehicles and electric vehicles are being put to practical use in terms of prevention of environmental pollution, and these next generation vehicles employ secondary battery technology to reduce the value and weight and increase the life span.

Generally, a secondary battery is a cylindrical, square, or pouch type battery. This is because the secondary battery is manufactured by inserting an electrode assembly composed of a cathode, an anode, and a separator into a pouch-shaped case of a cylindrical or rectangular metal can or an aluminum laminate sheet, and injecting an electrolyte into the electrode assembly. Therefore, since a certain space for mounting the secondary battery is indispensably required, there is a problem that the cylindrical shape, the square shape, or the pouch shape of the secondary battery acts as a constraint on the development of various types of portable devices. Thus, a new type of secondary battery capable of various shapes is required, and a linear battery is proposed, which is a battery having a very large ratio of length to cross-sectional diameter, which is excellent in flexibility.

Further, in the negative electrode active material, a carbonaceous material is mainly used as a negative electrode active material constituting a negative electrode of a lithium secondary battery at present. In the case of graphite, the theoretical capacity is about 372 mAh / g, and the actual capacity of graphite commercialized at present is about 350 to 360 mAh / g. However, such a capacity of a carbonaceous material such as graphite is not compatible with a lithium secondary battery which requires a high capacity of a negative electrode active material.

In order to satisfy such a demand, there is an example of using Si, Sn, or the like, which is a metal capable of electrochemically alloying with lithium and exhibiting a higher charge / discharge capacity than a carbonaceous material, as a negative electrode active material. However, such a metal-based negative electrode active material has a large volume change accompanied by the charge / discharge of lithium and cracks and becomes undifferentiated. Therefore, the capacity of the secondary battery using such a metal-based negative active material decreases sharply as the charge- There may be a problem of this being shortened.

In addition, the cable type secondary battery, which is required to have flexibility, is likely to suffer from disconnection due to frequent external physical impacts, such as when the secondary battery is broken due to its structural characteristics, and also uses an anode active material such as Si or Sn The active material may be detached due to expansion and contraction of the electrode due to repetitive charging and discharging.

Accordingly, an object of the present invention is to provide a negative electrode for a secondary battery which is a secondary battery using a high-capacity negative electrode active material and which prevents the negative electrode active material and the negative electrode collector from desorbing.

According to an aspect of the present invention, there is provided an anode for a secondary battery, comprising: a cathode; A copper-metal anode active material alloy; And an anode for a secondary battery having a continuous phase having a concentration gradient in the order of copper, a copper-metal-based anode active material alloy, and a metal-based anode active material, in the order from the center of the cathode toward the outer periphery thereof .

According to an embodiment of the present invention, the copper may serve as a current collector.

According to an embodiment of the present invention, the metal-based negative electrode active material may be selected from the group consisting of Si, Sn, Li, Zn, Mg, Cd, Ce, Ni or Fe; An alloy made of the metal system; (M) and Sn (Sn), which are Si, Li, Zn, Mg, Cd, Ce, Ni, or Fe, and the metal-based negative electrode active material may be a mixture of two or more of the above- (M-Sn alloy), wherein the copper-metal anode active material alloy may be a Cu-M-Sn alloy.

According to an embodiment of the present invention, the ratio (M / Sn) of the metal system (M) to Sn of the negative electrode active material may be 0.01 to 50.

According to an embodiment of the present invention, the negative electrode for a secondary battery may be obtained by heat-treating a material coated with a metal anode active material on a surface of at least a part of a collector of a copper material.

According to an embodiment of the present invention, the collector of the copper material may be of the wai type, and the heat treatment temperature is preferably 100 to 250 ° C, and the heat treatment time is preferably 10 minutes to 48 hours.

According to an embodiment of the present invention, the negative electrode for a secondary battery may have a horizontal section and extend in the longitudinal direction.

According to an embodiment of the present invention, the secondary battery may be a cable type secondary battery.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: preparing a collector of copper material; Coating a metal anode active material on at least a part of the surface of the collector of the copper material; And a step of heat-treating a current collector made of a copper material coated with the metal-based negative electrode active material, wherein the negative electrode for a continuous-phase secondary battery having a concentration gradient in the order of copper, a copper-metal based negative electrode active material alloy, ≪ / RTI >

In the above production method, the current collector of the copper material may be wire-shaped, and the heat treatment temperature is preferably 100 to 250 ° C, and the heat treatment time is preferably 10 minutes to 48 hours.

According to another aspect of the present invention, there is provided a lithium secondary battery including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, wherein the negative electrode is a negative electrode according to the present invention.

According to another aspect of the present invention, there is provided an internal electrode comprising at least one negative electrode for a secondary battery according to the present invention; A separation layer which surrounds the internal electrode and is filled with ions and serves as a passage for ions; An external electrode which surrounds the outer surface of the separating layer and is an anode having a cathode active material layer and a cathode current collector; And a protective coating disposed around the outer electrode. The cable-type secondary battery has a horizontal cross-section and extends in the longitudinal direction.

According to another aspect of the present invention, there is provided a lithium secondary battery comprising: an internal electrode including a cathode current collector and a cathode active material layer formed on a surface of the cathode current collector; A separation layer filled in the internal electrode and serving as an ion passage; An outer electrode surrounding the outer surface of the separation layer and including a cathode according to the present invention; And a protective coating disposed around the outer electrode. The cable-type secondary battery has a horizontal cross-section and extends in the longitudinal direction.

The present invention relates to a copper-metal anode active material alloy formed by alloying two materials at the boundary between an anode current collector and a negative electrode active material in a high capacity cathode for a secondary battery, wherein the anode active material, which has been particularly problematic in a high capacity cathode for a secondary battery, It is possible to solve the problem of deteriorating characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the invention and, together with the description of the invention, It should not be construed as limited.
1 is a schematic cross-sectional view of a cathode according to an embodiment of the present invention.
2 schematically illustrates a method of manufacturing a cathode according to an embodiment of the present invention.
3 is a cross-sectional view of a cable-type secondary battery including a negative electrode according to an embodiment of the present invention.
4 is a cross-sectional view of a cable-type secondary battery including a plurality of cathodes according to an embodiment of the present invention.
5 is a graph showing charge / discharge test of a cable type secondary jersey according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in the present specification and the constitutions described in the drawings are merely the most preferred embodiments, and not all of the technical ideas of the present invention are described. Therefore, various equivalents which can be substituted at the time of the present application It should be understood that variations can be made.

According to an aspect of the present invention, there is provided an anode for a secondary battery, comprising: a cathode; A copper-metal anode active material alloy; And an anode for a secondary battery having a continuous phase having a concentration gradient in the order of copper, a copper-metal-based anode active material alloy, and a metal-based anode active material, in the order from the center of the cathode toward the outer periphery thereof . At this time, the copper serves as a current collector.

The inventors of the present invention are characterized in that they attempted alloying between the negative electrode collector and the negative electrode active material in order to prevent the desorption phenomenon between the negative electrode collector and the high capacity negative electrode active material. Accordingly, it is possible to prevent detachment of the negative electrode collector and the negative electrode active material while maintaining the function of the negative electrode active material, and to improve the lifetime characteristics of the battery.

Alloying between the negative electrode current collector and the negative electrode active material of the present invention can also be attempted in a negative electrode having a horizontal section and extending in the longitudinal direction. In the case of a negative electrode using a wire-like current collector and a high-capacity negative electrode active material coated on the surface of the current collector, the secondary battery including the negative electrode has excellent flexibility. However, when the negative electrode is manufactured or charged / discharged, There is a phenomenon that the separation phenomenon between the negative electrode current collector and the negative electrode active material is worsened as compared with the film negative electrode current collector due to the problem of being generated in all directions different from the film type and the flexibility of the negative electrode and the volume expansion of the negative electrode active material. The present inventors have devised the present invention in order to prevent the deterioration of the negative electrode collector and the negative electrode active material, which are more problematic in the case of the negative electrode having such a horizontal cross section and extending in the longitudinal direction.

Fig. 1 schematically shows an embodiment of a negative electrode for a secondary battery according to the present invention. It should be noted, however, that the embodiments shown in the following description and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It should be understood that various equivalents and modifications may be present.

Referring to FIG. 1, the cathode 100 for a secondary battery according to the present invention is of wire type having one of various horizontal cross sections and extending in the longitudinal direction. In the cathode 100, the copper 11 is located in the center of the cathode 100 for the secondary battery, the copper-metal anode active material alloy 12 is located in the periphery of the copper 11, 13 are located around the copper-metal-based negative electrode active material alloy 12 and have a concentration gradient in the order of copper, a copper-metal negative electrode active material alloy, and a metal negative electrode active material in the order of the outer periphery of the negative electrode And has a continuous phase.

In one embodiment of the present invention, the negative electrode active material coated on the negative electrode collector to provide a high capacity can be a metal-based negative electrode active material, such as Si, Sn, Li, Zn, Mg, Cd, Ce, Ni or Fe; An alloy made of the metal system; , Or a mixture of two or more thereof. The metallic anode active material as described above has a problem of separation between the anode current collector and the anode active material due to high capacity or volume expansion in the anode for the secondary battery, but the present invention solves the problem through alloying.

The metal-based negative electrode active material according to the present invention is an alloy (M-Sn alloy) of metal (M) and Sn (M-Sn alloy) having Si, Li, Zn, Mg, Cd, Ce, Ni or Fe, The alloy is a Cu-M-Sn alloy. When the M-Sn alloy is used as the negative electrode active material as described above, a negative electrode having a high capacity and stable lifetime characteristics can be manufactured.

According to one embodiment of the present invention, the ratio (M / Sn) of the metal system (M) to Sn of the negative electrode active material may be 0.01 to 50, or 10 to 40. In the case of the above range, a negative electrode having a high capacity can be manufactured while controlling the volume expansion of Sn.

The secondary battery negative electrode as described above may be used for a cable type secondary battery having improved adhesion between the negative electrode current collector and the negative electrode active material as in the present invention through heat treatment of the copper current collector and at least a part of the surface of the current collector coated with the negative electrode active material. A cathode can be provided.

FIG. 2 schematically shows a manufacturing method according to an embodiment of a negative electrode for a secondary battery according to the present invention. It should be noted, however, that the embodiments shown in the following description and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It should be understood that various equivalents and modifications may be present.

Referring to FIG. 2, the cathode 100 for a secondary battery according to the present invention comprises a cathode 10 for a cable-type secondary battery in which a metallic anode active material 2 is coated on the surface of a wire- . The cathode 100 for a secondary battery having a concentration gradient in the order of copper, a copper-metal-based anode active material alloy, and a metal-based anode active material may be obtained from the central portion of the cathode through the heat treatment.

In the method for manufacturing a negative electrode for a secondary battery according to the present invention, the temperature is preferably 100 to 250 ° C or 150 to 200 ° C. The copper and the anode active material can be easily diffused in the temperature range, and the metal-based active material, such as Sn, is not vaporized. The heat treatment time is preferably 10 minutes to 48 hours or 1 hour to 24 hours. The copper and the anode active material can be easily diffused within the time range described above and the copper remains in the center of the negative electrode for the secondary battery without being diffused to the outside to function as a current collector.

The negative electrode for a secondary battery according to the present invention may have a horizontal section and extend in the longitudinal direction. In such a case, desorption between the negative electrode current collector and the negative electrode active material can be effectively controlled.

The negative electrode for a cable-type secondary battery according to the present invention may be a wire type or a wound wire type. Since the wound wire-type negative electrode has elasticity, it plays a role of dispersing the force at the time of deformation according to the external force, so that the deformation of the active material layer is small and the detachment of the negative electrode active material is prevented, It is possible to obtain a more excellent effect for preventing the negative electrode active material from desorbing.

Further, the secondary battery according to the present invention may be a cable type secondary battery, and therefore, the negative electrode for a secondary battery according to the present invention may be a negative electrode for a cable type secondary battery.

A negative electrode for a secondary battery according to the present invention is manufactured as follows.

Preparing a current collector of copper material; Coating a metal anode active material on at least a part of the surface of the collector of the copper material; And a step of heat-treating a current collector made of a copper material coated with the metal-based negative electrode active material, wherein the negative electrode for a continuous-phase secondary battery having a concentration gradient in the order of copper, a copper-metal based negative electrode active material alloy, and a metallic negative electrode active material is prepared .

According to an embodiment of the present invention, the current collector of the copper material may be wire-shaped.

In the heat treatment of the negative electrode for a secondary battery according to the present invention, the temperature is preferably 100 to 250 占 폚 or 150 to 200 占 폚. The copper and the anode active material can be easily diffused in the temperature range, and the metal-based active material, such as Sn, is not vaporized. The heat treatment time is preferably 10 minutes to 48 hours or 1 hour to 24 hours. The copper and the anode active material can be easily diffused within the time range described above and the copper remains in the center of the negative electrode for the secondary battery without being diffused to the outside to function as a current collector.

According to another aspect of the present invention, there is provided a lithium secondary battery including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, wherein the negative electrode is a negative electrode according to the present invention do.

The negative electrode is a negative electrode according to the present invention, and the other components use a configuration and a manufacturing method used in an ordinary secondary battery.

In addition, the present invention can provide a cable-type secondary battery using the negative electrode according to the present invention.

Hereinafter, a concrete structure of a cable-type secondary battery having a cathode according to the present invention will be briefly described with reference to FIGS. 3 and 4. FIG.

3 and 4 schematically show an embodiment of a cable-type secondary battery according to the present invention. It should be noted, however, that the embodiments shown in the following description and the configurations shown in the drawings are only the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It should be understood that various equivalents and modifications may be present.

Referring to FIG. 3, the cable-type secondary battery 500 of the present invention includes an inner electrode including a cathode 100 for a cable-type secondary battery according to the present invention; An isolation layer 510 surrounding the internal electrode and filled with ions, An external electrode that surrounds the outer surface of the separating layer and includes a cathode active material 520 and a cathode current collector 530; And a protective sheath 540 disposed around the outer electrode, and having a horizontal section and extending in the longitudinal direction.

4, The cable type secondary battery 600 according to the present invention includes an internal electrode including a plurality of cathodes 100 for a cable type secondary battery according to the present invention using several cathodes 100 for a cable type secondary battery according to the present invention. A separation layer 610 that surrounds the plurality of internal electrodes and is filled with ions and serves as a passage for ions; An external electrode which surrounds the outer surface of the separating layer and includes a cathode active material 620 and a cathode current collector 630; And a protective sheath 640 disposed around the outer electrode, and having a horizontal section and extending in the longitudinal direction. In the case where a plurality of internal electrodes are provided, since the contact area increases, it has a high battery rate and it is easy to adjust the capacity balance between the internal electrode and the external electrode by adjusting the number of internal electrodes.

The cathode 100 for a cable-type secondary battery according to the present invention may be used as an internal electrode or an external electrode as shown in FIGS. 3 and 4. That is, an internal electrode including at least one or more positive electrode current collectors and positive electrode active material layers formed on the surface of the positive electrode current collector; A separation layer filled in the internal electrode and serving as an ion passage; An outer electrode which is an anode for a cable type secondary battery according to the present invention that surrounds the outer surface of the separating layer; And a protective covering disposed around the outer electrode, and having a horizontal section and extending in the longitudinal direction.

The separating layer of the present invention can use an electrolyte layer or a separator.

As the electrolyte, a gel type polymer electrolyte using PEO, PVdF, PVdF-HFP, PMMA, PAN or PVAC; Or a solid electrolyte using PEO, polypropylene oxide (PPO), polyethylene imine (PEI), polyethylene sulphide (PES) or polyvinyl acetate (PVAc). As the electrolyte, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylene carbonate (VC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate , Non-aqueous electrolytes using methyl formate (MF), gamma-butyrolactone, sulfolane, methylacetate (MA), or methyl propionate (MP) May be used. Then, the electrolyte is used, which may further include a lithium salt, the lithium salt is _{LiCl, LiBr, LiI, LiClO 4} , LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6 , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, (CF ₃ SO ₂ ) ₂ NLi, chloroborane lithium, lower aliphatic carboxylate lithium and lithium tetraphenylborate.

The separator is not limited in its kind, but may be made of a porous material made of a polyolefin-based polymer selected from the group consisting of ethylene homopolymer, propylene homopolymer, ethylene-butene copolymer, ethylene-hexene copolymer and ethylene-methacrylate copolymer materials; A porous substrate made of a polymer selected from the group consisting of polyester, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyethersulfone, polyphenylene oxide, polyphenylsulfite and polyethylene naphthalene; Or a porous substrate formed of a mixture of inorganic particles and a binder polymer. Particularly, in order for the lithium ions in the lithium ion supply core portion to be easily transferred to the external electrode, it is preferable to use the above polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyether sulfone, polyphenylene oxide, It is preferable to use a separator made of a nonwoven fabric corresponding to a porous substrate made of a polymer selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, and polyethylene naphthalene.

When the internal electrode of the cable-type secondary battery is a negative electrode according to the present invention and the external electrode is an anode, the positive electrode is coated with a positive electrode active material on the positive electrode current collector. More specifically, the positive electrode active material And a positive electrode collector formed to surround the outer surface of the positive electrode active material or a positive electrode collector formed to surround the outer surface of the separator layer and a positive electrode active material layer surrounding the outer surface of the positive electrode collector, A cathode active material layer formed to surround the outer surface of the separator layer, or a cathode active material layer surrounding the outer surface of the separator layer; A positive electrode current collector which is covered in the positive electrode active material layer and surrounds the outer surface of the separating layer in a spaced- . Also, the external electrode of the cable-type secondary battery may be a negative electrode according to the present invention, the internal electrode may be a positive electrode, and the external electrode may be variously applied to the positive electrode active material layer and the positive electrode collector.

The shape of the cathode current collector as the external electrode is not particularly limited, but a pipe-shaped current collector, a wound wire-like current collector, a wound sheet-like collector, or a mesh-shaped current collector can be used.

Wherein the positive electrode current collector is made of stainless steel, aluminum, nickel, titanium, sintered carbon, copper; Stainless steel surface-treated with carbon, nickel, titanium or silver; Aluminum-cadmium alloy; A nonconductive polymer surface-treated with a conductive material; Conductive polymer; A metal paste containing a metal powder of Ni, Al, Au, Ag, Al, Pd / Ag, Cr, Ta, Cu, Ba or ITO; Or a carbon paste comprising carbon powder which is graphite, carbon black or carbon nanotube.

As the cathode active material, a lithium-containing transition metal oxide may be preferably used. For example, LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , Li (Ni _a Co _b Mn _c ) O ₂ , 0 <b <1, 0 <c <1, a + b + c = 1), LiNi 1 - y Co y O 2, LiCo 1 - y Mn y O 2, LiNi 1 -y Mn y O 2 (O ≤y <1), Li (Ni a Co b Mn c) O 4 (0 <a <2, 0 <b <2, 0 <c <2, a + b + c = 2), LiMn 2 - z Ni _z O ₄ , LiMn _{2 -z} Co _z O ₄ (0 <z <2), LiCoPO ₄ and LiFePO ₄ , or a mixture of two or more thereof. In addition to these oxides, sulfide, selenide and halide may also be used.

The external electrode according to the present invention includes an external current collector and an external electrode active material. The external electrode may be a cathode or an anode, and may be formed by a suitable one of the following embodiments. The external electrode active material layer may be formed in advance in the external current collector and then applied to the separation layer to form the external electrode. For example, in the case of the wound sheet-like current collector, the external electrode active material layer may be formed on the sheet-like current collector, and the sheet-like external electrode may be prepared by cutting it to have a predetermined width. Thereafter, the outer electrode active material layer is brought into contact with the separation layer, and the outer surface of the separation layer is wound around the prepared sheet-like outer electrode to form the outer electrode on the separation layer.

Alternatively, at the time of forming the external electrode, the external current collector may be formed first to surround the outer surface of the separating layer, and the external electrode active material layer may be formed to surround the outer surface of the external current collector.

In the case where the external electrode includes an external current collector surrounding the outer surface of the isolation layer and an external electrode active material layer surrounding the outer surface of the external current collector and contacting the isolation layer, A wire-like or sheet-like external current collector is wound on the outer surface, for example. The winding method is not particularly limited, but in the case of a wire-shaped external current collector, a winding machine can be applied to wind the outer surface of the separation layer. The outer electrode active material layer is formed by coating the outer surface of the wound current collector or sheet-like external current collector. The outer electrode active material layer is formed so as to be in contact with the separator layer surrounding the wound external current collector.

An outer electrode active material layer formed on the outer surface of the separator layer to surround the outer surface of the separator layer; and an external current collector formed on the outer electrode active material layer and surrounding the outer surface of the separator layer, , A part of the external electrode active material layer to be finally obtained is first formed on the outer surface of the separating layer, and then the external electrode active material layer is formed on the external current collector, To completely cover the external current collector. At this time, since the external current collector is located inside the external electrode active material layer in a state of being separated from the separating layer, the electric contact between the current collector and the active material can be improved, thereby contributing to the improvement of the characteristics of the battery

The electrode active material, which is a negative electrode active material or a positive electrode active material, includes a binder and a conductive material, and may be combined with a current collector to form an electrode.

Such a cathode can be produced by extrusion coating an electrode slurry containing a cathode active material on a cathode current collector through an extruder. The cathode may be formed by coating the outside of the internal electrode with the separating layer or inserting the internal electrode into the separating layer using the cathode as the internal electrode. The inner electrode and the separating layer are formed as described above, and the outer electrode and the protective coating are formed on the outer surface of the separating layer. Also, a method of manufacturing an internal electrode by inserting an internal electrode into a separation layer after forming an external electrode and a protective coating including a separation layer, or by inserting an internal electrode after forming an external electrode and a protective coating, It is possible.

The protective coating of the present invention is formed as an insulator on the outer surface of the battery to protect the electrode against moisture in the air and external impact. As the protective coating, a conventional polymer resin can be used. For example, PVC, HDPE or epoxy resin can be used.

Hereinafter, embodiments of the present invention will be described in detail to facilitate understanding of the present invention. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the following embodiments. Embodiments of the invention are provided to more fully describe the present invention to those skilled in the art.

<Examples>

Example  One. Cu - Ni - Sn  Cathode for a cable type secondary battery formed with an alloy.

Ni-Sn was electroplated to a thickness of 2.5 占 퐉 on the surface of a wire-shaped Cu current collector having a diameter of 150 占 퐉 to coat the negative electrode active material layer. Thereafter, heat treatment was performed at 200 ° C for 12 hours to prepare a negative electrode having a Cu-Ni-Sn alloy.

Comparative Example  One. Cu - Ni - Sn  Cathode for a cable type secondary battery in which no alloy is formed.

Sn-Ni was electroplated to a thickness of 2.5 占 퐉 on the surface of a wire-shaped Cu current collector having a diameter of 150 占 퐉 to prepare a negative electrode coated with the negative active material layer.

<Production Example>

Coin type  Manufacture of half-cell

As the positive electrode, metal lithium foil was used and the negative electrode prepared in Example 1 and Comparative Example 1 was used. An electrode assembly was fabricated with a polyethylene separator interposed between the positive electrode and the negative electrode. The prepared electrode assembly was inserted into a battery case, and an electrolytic solution containing 1M LiPF ₆ was added to a nonaqueous solvent mixed with ethylene carbonate: diethyl carbonate = 1: 2 (volume ratio) to prepare a coin type half cell.

<Test Example 1 Charging and discharging characteristics of the battery>

The first charge-discharge characteristics and life characteristics of the coin cell of Preparation Example 1 produced using the negative electrode active material of Example 1 and Comparative Example 1 were measured under the following conditions, and the results are shown in the following Table 1 and FIG. 5 .

Coin type  Half-cell Charging and discharging  Condition

- Charging of the cell: After charging at a constant current up to 5 mV, it was charged at a constant voltage until the current reached 0.005 C at 5 mV.

- Discharge of the battery: The discharge was performed at a constant current up to 1.0 V.

Discharge capacity
(mAh / g) Capacity before charge
(mAh / g) Initial efficiency
(%) Normalized Capacity (%)
@ 30th cycle Expansion (%)
(Thickness after expansion / thickness before expansion * 100) Example 1 746.7 654.3 87.63 54 160 Comparative Example 1 745.5 651.0 87.33 27 240

The charge / discharge test is shown in Table 1 and FIG. 5. FIG. 5 is represented by a red line corresponding to Example 1 and a black color corresponding to Comparative Example 1. The negative electrode according to Example 1 was used as the negative active material and negative electrode collector It was found that the adhesive strength to the whole was improved to 30% at 30 cycles (Comparative Example 1) to 50% (Example 1), and the lifetime characteristics were improved.

1 - Wire type collector of copper material
2 - Metal anode active material
10 - Cathode for Conventional Cable Type Secondary Battery
11 - The collector of copper material
12 - Copper-metal anode active material alloy
13 - Metal anode active material
100 - cathode for cable type secondary battery
510, 610 - separation layer
520, 620 - cathode active material
530, 630 - Positive Current Collector
540, 640 - protective clothing
500, 600 - Cable type secondary battery

Claims (18)

A negative electrode for a secondary battery,
Copper; A copper-metal anode active material alloy; And a metal-based negative electrode active material,
And a continuous phase having a concentration gradient in the order of copper, a copper-metal-based anode active material alloy, and a metal-based anode active material, in the order from the center of the cathode toward the outer surface. The method according to claim 1,
Wherein the copper is a current collector. The method according to claim 1,
Wherein the metal-based negative electrode active material is selected from the group consisting of Si, Sn, Li, Zn, Mg, Cd, Ce, Ni or Fe; And an alloy composed of the metal system, or a mixture of two or more thereof. The method according to claim 1,
Wherein the metal-based negative electrode active material is an alloy of M and Sn (M-Sn alloy) of Si, Li, Zn, Mg, Cd, Ce, Ni or Fe and the alloy of Cu and the negative electrode active material is Cu- Sn alloy cathode for a secondary battery. 5. The method of claim 4,
Wherein the negative electrode active material has a metal (M) to Sn (M / Sn) ratio of 0.01 to 50. The method according to claim 1,
The negative electrode for a secondary battery is obtained by heat-treating a material in which a metallic negative electrode active material is coated on at least a part of a surface of a copper current collector. The method according to claim 6,
Wherein the current collector of the copper material is a wire type negative electrode for a secondary battery. The method according to claim 6,
The heat treatment temperature is in the range of 100 to 250 ° C. The method according to claim 6,
And the heat treatment time is 10 minutes to 48 hours. The method according to claim 1,
Wherein the negative electrode for a secondary battery has a horizontal section and extends in the longitudinal direction. The method according to claim 1,
Wherein the secondary battery is a cable type secondary battery. Preparing a current collector of copper material;
Coating a metal anode active material on at least a part of the surface of the collector of the copper material; And
And heat treating the current collector of the copper material coated with the metal anode active material,
A method for manufacturing a negative electrode for a continuous-phase secondary battery having a concentration gradient in the order of copper, a copper-metal-based anode active material alloy, and a metal-based anode active material. 13. The method of claim 12,
Wherein the collector of the copper material is a wire type. 13. The method of claim 12,
Wherein the heat treatment temperature is 100 to 250 ° C. 13. The method of claim 12,
And the heat treatment time is 10 minutes to 48 hours. A lithium secondary battery comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode,
The negative electrode according to any one of claims 1 to 10, wherein the negative electrode is a negative electrode. An internal electrode comprising at least one negative electrode for a secondary battery according to any one of claims 1 to 11;
A separation layer which surrounds the internal electrode and is filled with ions and serves as a passage for ions;
An external electrode which surrounds the outer surface of the separating layer and is an anode having a cathode active material layer and a cathode current collector; And
And a protective covering disposed around the outer electrode, wherein the cable-type secondary battery has a horizontal section and extends in the longitudinal direction. An internal electrode including at least one positive electrode collector and a positive electrode active material layer formed on the surface of the positive electrode collector;
A separation layer filled in the internal electrode and serving as an ion passage;
An outer electrode surrounding the outer surface of the separation layer and including a negative electrode for a secondary battery according to any one of claims 1 to 11 in the form of a wire; And
And a protective covering disposed around the outer electrode, wherein the cable-type secondary battery has a horizontal section and extends in the longitudinal direction.

Images