[Mutual citations and related applications;
[2]
This application claims the benefit of priority based on the 15th Korea Patent Application No. 10-2017-0118693 September 2017, and all information disclosed in the literature of the Korea patent application are included as part of the specification.
[3]
[Technology]
[4]
The present invention relates to a lithium secondary battery anode, and relates to a lithium secondary battery comprising the same, and more particularly, insulated properties enhanced unified stack cell (unified stack cell) for a lithium secondary battery negative electrode and a lithium secondary battery comprising the same.
BACKGROUND
[5]
The demand for secondary batteries as an energy source, and is rapidly increased as the development of technology and the demand for mobile devices increases, Among such secondary battery shows a high energy density and operating potential, a long cycle life, self-discharge rate is low lithium secondary the battery is commercially available and widely used.
[6]
The lithium secondary battery is typically the positive electrode, composed of a negative electrode, a separator and an electrolyte comprising a negative electrode active material is inserted in the lithium ion comprising the positive electrode active material is made of a secondary battery is charged and discharged by a desorption (intercalation-decalation). Lithium secondary batteries are therefore high energy density (energy density), have the advantage of a large electromotive force can demonstrate the capacity has been applied to various fields.
[7]
In general, the lithium secondary battery is prepared, insert after overlapped alternately each other, a positive electrode, a negative electrode and a separator, a predetermined size and shape of the battery case made of the can (can), or a pouch (pouch) of, and finally injecting the electrolytic solution.
[8]
The secondary battery is overcharged to more than the normal charged condition or the negative electrode plate and positive electrode plate of the electrode assembly when the short circuit is a lithium salt and an organic solvent, a lithium metal side occur the decomposition of the mixed electrolyte anode plate deposited on the bipolar plate side of the battery characteristics deteriorated and the internal It can cause a short circuit. It issues a conventional lithium secondary battery according to the short of the secondary battery as described above attempts to solve using the characteristics of the separator. The separator is not only provides a passage through which lithium ions as a polymer membrane having a porous structure is located between the anode and the cathode can move actively, also serves to prevent contact of the anode and the cathode.
[9]
Recently, an attempt is made to introduce a thin separator is made for the production of a lithium secondary battery having a high energy density. The ionic conductivity of the non-aqueous liquid electrolyte is required and because it is very lower than that of the aqueous electrolyte in order to achieve high output, high energy density of the cell increasing the reaction area of ​​the electrode reduces the distance between the plates. Therefore, by reducing the thickness of the separator to increase the concentration of the electrolyte around the separator, there has been an attempt to promote mass transfer. However, when the thickness of the separator is thinner, there is a problem in that the manufacturing process pinhole (pinhole) occurs or the separator is torn becomes more likely to occur a short circuit safety is lowered. As its resolution is getting attention unified stack (unified stack cell) cell was interposed between the ceramic layers in place of the conventional polyolefin separator, an anode and a cathode.
[10]
However, the use of a ceramic layer in place of the conventional polyolefin separator There is no problem of pinholes such as a conventional polyolefin separator, the ceramic layer also has a problem that the insulating properties and stability deteriorate when reducing its thickness in order to improve energy density a situation which must have a certain level of thickness.
[11]
Thus, a new method for solving the insulating ceramic layer and reliability deterioration problems which may occur when have a thickness of less than a certain level is required to reduce the thickness of the ceramic layer used as a separator.
Detailed Description of the Invention
SUMMARY
[12]
The problem to be solved by the present invention is to provide a unified stack in isolation characteristic enhanced cell (unified cell stack) for a lithium secondary battery negative electrode.
[13]
The problem to be solved another of the present invention to provide an insulating property is enhanced unified cell stack (unified stack cell) rechargeable lithium battery including the negative electrode for a lithium secondary battery.
Problem solving means
[14]
In order to achieve the foregoing object, the present invention provides a negative active material layer; And a ceramic separation layer formed on the anode active material layer, the negative electrode active material layer had an arithmetic average surface roughness (Ra) 0.01 ㎛ to 0.3 ㎛, the ceramic separation layer has a thickness of 1 ㎛ to 30 ㎛, It provides a lithium secondary battery negative electrode.
[15]
In order to solve the above other problem, the present invention includes the negative electrode, and an anode, and provides a lithium secondary battery positive electrode active material layer disposed on the anode is in contact with a ceramic separating layer of the negative electrode.
Effects of the Invention
[16]
Since the lithium secondary battery anode of the present invention the surface roughness, including the negative electrode active material layer controlled below a certain level, improves the insulating properties of the ceramic separation layer formed on the anode active material layer can exhibit an enhanced safety, the ceramic close contact with the positive electrode in the lithium secondary battery prepared by the separation layer can also exhibit an excellent safety.
Brief Description of the Drawings
[17]
1 is a view schematically showing a cross section of a lithium secondary battery comprising a lithium secondary battery negative electrode according to an example of the present invention.
[18]
Figure 2 is a picture taken with the laminate surface of the negative electrode of Example 1 using SEM.
[19]
Figure 3 is a picture taken by using the SEM to the laminate surface of the lithium secondary battery of Example 5.
Best Mode for Carrying Out the Invention
[20]
Hereinafter, the present invention will be described to assist understanding of the present invention in more detail.
[21]
Herein and in the terms or words used in the claims is general and not be construed as limited to the dictionary meanings are not, the inventor can adequately define terms to describe his own invention in the best way on the basis of the principle that, interpreted based on the meanings and concepts corresponding to technical aspects of the present invention.
[22]
[23]
The lithium secondary battery anode of the present invention, the negative electrode active material layer; And the anode active material layer, and comprising a ceramic isolation layer formed on the anode active material layer are those, wherein arithmetic mean surface roughness (Ra) 0.01 ㎛ to 0.3 ㎛. Further, the ceramic separation layer will have a thickness of 1 ㎛ to 30 ㎛.
[24]
The arithmetic mean surface roughness (Ra) of the negative electrode coating portion may be in the 0.01 to 0.3 ㎛ ㎛, may be specifically 0.05 ㎛ to 0.2 ㎛, more specifically 0.1 to 0.2 ㎛ ㎛. The arithmetic mean surface roughness (Ra) of the negative electrode active material layer if satisfied the above range, there is a ceramic separation layer on the negative electrode active material layer can be uniformly formed, and the ceramic isolation layer can maintain the insulating property in the battery when using the stable so that the battery containing the same may exhibit excellent stability. In addition, the arithmetic average surface roughness (Ra) of the negative electrode active material layer if satisfied the above range, even if the thickness of the lithium secondary battery, the ceramic separation layer that can perform the separation membrane as a function of the ceramic separation layer suitable It can maintain the mechanical strength to reliably perform the function as the separation membrane, so it is possible to thin a thickness of 1 ㎛ to 30 ㎛ than the thickness of the separation membrane made of the thickness of the ceramic separating layer in a conventional polyolefin-based resin and the like.
[25]
That is, since the lithium secondary battery anode of the present invention is adjusted so that the surface roughness (roughness) of the negative electrode active material layer may have a constant arithmetic average surface roughness (Ra) values, a ceramic separation layer uniformly on the anode active material layer It can be formed, in which the ceramic isolation layer can maintain the insulation properties stably using the cell. Thus, the battery comprising a lithium secondary battery anode of the present invention can exhibit excellent stability.
[26]
The negative electrode active material layer Average particle size (D in 7 ㎛ to 30 ㎛ comprising the lithium secondary battery anode of the present invention 50 average of having a negative electrode active material, specifically 10 ㎛ to 25 ㎛, more specifically 10 ㎛ to 20 ㎛ a) particle size (D 50 may include a negative electrode active material having an).
[27]
When including the negative electrode active material layer in this case comprise a negative electrode active material of a small particle diameter than the above range, the discharge capacity of the negative electrode is reduced, and the initial efficiency may decrease, the negative electrode active material of a larger particle size than the above range, the negative electrode slurry is it is difficult to appropriately coated with a uniform thickness, while the negative electrode active material layer have a porosity appropriate surface finish (roughness), it is difficult to have a range of the arithmetic average surface roughness (Ra) value.
[28]
In the lithium secondary battery negative electrode according to an example of the present invention, the negative electrode active material may include a graphite-based active material.
[29]
The graphite-based active material is natural graphite, artificial graphite, Kish graphite (kish graphite), pyrolytic carbon (pyrolytic carbon), liquid crystal pitch based carbon fibers (mesophase pitch based carbon fiber), carbon microspheres (meso-carbon microbeads), a liquid crystal pitch (mesophase pitches), petroleum-based coke, and may be at least one member selected from the group consisting of coal coke, specifically, a plurality of primary particles made of graphite (initial particle) is set, or combined with the secondary particles of sphere (secondary paricles ) it may be a block of graphite have the structure. In this case, the secondary particle structure has a primary particle of the plurality may be localized to each other set, bonding or assembly acts as critical.
[30]
The terms used in the context of the invention, "primary particles" means the original particles when forming the particles of a different kind from which the particles, to screen a plurality of the primary particles aggregate, bonded or assembled to form secondary particles can do.
[31]
As used herein, the term "secondary particles" refers to the large particles, to discern the physical screen is formed by individual primary particles aggregate, a bond or assembly.
[32]
The primary particles of the block of graphite may be a needle cokes (needle cokes), mosaic coke (mosaic cokes) and coal tar pitch (coaltar pitch) the group of artificial graphite was calcined to crystallize the carbon raw material at least one member selected from the consisting of, specifically a it may be one having a crystal structure of the synthesized optically isotropic petroleum pitch to the coke on the show through the source.
[33]
It said first edge portion of the particles is able to have a layer structure, bent in a polygonal shape, and therefore the solvent molecules even in the state for times in the lithium in the graphite inter-layer co-intercalation rates, the graphite layers are bent in a polygonal shape of the edge portion since the structure, it tends to be wider than the graphite layers in a graphite with high crystallinity, so therefore less affected by steric hindrance the solvent decomposition is suppressed. In other words, since the graphite layers are bent in a polygonal structure according to an edge portion, the decomposition reaction of the solvent of the electrolyte, etc. in the non-aqueous electrolyte secondary battery can be suppressed. The structure can be confirmed by a transmission electron microscope (TEM).
[34]
When used as the block of graphite in the negative electrode active material of a lithium secondary battery, low irreversible capacity at the time of activation, is excellent in the rapid-discharge characteristics, it is possible to produce a superior cycle characteristics of lithium secondary batteries, in particular, the negative electrode without the need for a separate coating layer the active material layer may have an arithmetic average surface roughness (Ra) value of the above range.
[35]
The negative electrode active material layer is 1,000 kg / m 3 when applied and the pressure the pellet density 1.7 g / cc or more, for example 1.8 g / cc to about 2.2 g / cc, is intended more specifically, 1.8 g / cc to about 1.9 g / cc can.
[36]
The pellet density of the negative electrode slurry forming the anode active material layer placed in a jig petrit kg 1,000 / m 3 shows the density of the pellets when the pellets were made by (pellet) shape by applying a pressure of.
[37]
If a pellet density of the negative electrode active material layer satisfies the above range, the negative electrode active material layer containing the same wherein the average particle diameter (D 50 ) of the above-described range, containing a negative electrode active material is in the range of the arithmetic average surface roughness (Ra) meets the value can.
[38]
Further, the anode active material layer are the negative degree of orientation of the negative electrode active material measured by XRD when the active material density of the negative electrode slurry forms a layer 1.6 g / cc (I 004 / I 110 a) is 50 or more, for example 50 to 70, It may be more specifically 50 to 65.
[39]
The degree of orientation (I of the negative electrode active material layer 004 / I 110 ) includes an electrode condition X-ray diffraction analysis on by the (004) plane and (110) peak intensity ratio (I on side 004 / I 110 a), the peak intensity ratio of X may be obtained via a ray diffraction analysis, the electrode state X-ray diffraction analysis means producing the negative electrode active material as a negative electrode state and subjected to X-ray diffraction analysis. The X-ray diffraction can be measured using a Cu-Kα ray using an X-ray diffractometer Bruker D4 Endeavor, may be a correction value through the Topas3 fitting program. It can be measured using high-purity silicon as an internal standard sample, calculated according to hakjin method (Japan Society for the Promotion of claim 17 established by measurement Committee).
[40]
A lithium secondary battery negative electrode according to an example of the present invention has been that the negative electrode active material layer comprises by selecting the negative electrode active material that can have a pellet (pellet) density and a negative orientation of a constant value as the negative electrode active material, reduce the surface roughness to be particularly having an average particle diameter of the negative electrode active material contains a small or that the anode active material layer, such as a separate coating layer the arithmetic mean surface roughness (Ra) value of the above range even if the anode active material layer is not formed on the one. The negative active material may be a graphite-based negative electrode active material specifically.
[41]
That is, the lithium secondary battery negative electrode according to an example of the present invention, by selecting a specific anode active material having a suitable particle size range as the negative electrode active material at the same time, the negative electrode having a pellet density and a negative orientation of the constant value, the arithmetic average surface roughness of the surfaces ( Ra), and this value can be available for the suitable range, with also exert an appropriate discharge capacity and an excellent initial efficiency through this, it is possible to improve the insulating property and reliability of a ceramic separation layer.
[42]
On the other hand, in a lithium secondary battery negative electrode according to another exemplary embodiment of the present invention, the negative electrode active material layer may be to include a second negative electrode active material layer formed on the first anode active material layer and a first negative electrode active material layer.
[43]
In this case, the first negative electrode active material layer has an average particle size (D in 5 ㎛ to 30 ㎛ 50 having the negative electrode active material, and specifically 6 ㎛ to 25 ㎛, more specifically 7 ㎛ to 20 ㎛ the average particle diameter (D a) 50 a) has may include a negative electrode active material and the second negative electrode active material layer is 0.03 ㎛ to the average particle diameter (D in 7 ㎛ 50 negative electrode active material having a), specifically, the average particle diameter (D of 0.03 ㎛ to 5 ㎛ 50 negative electrode having a) It may include active material.
[44]
Negative electrode active material comprising the first anode active material layer is capable of graphite may be in the active material, wherein the second anode active material layer negative electrode active material containing the the reversible intercalation of lithium and di intercalation as described above, compound If it is not particularly limited. Specifically, the first may be a negative electrode active material layer contains a negative electrode active material is graphitized graphite powder, a negative electrode active material containing the negative electrode active material layer 2 may be a block of graphite.
[45]
The powder (powder, powder) graphite and graphitized is that there is a plurality of primary particles made of graphite is a union, or a coupling assembly, it may be form a bulk. Primary particles of the powdery graphite may be a needle cokes (needle cokes), mosaic coke (mosaic cokes) and coal tar pitch (coaltar pitch) the group of artificial graphite was calcined to crystallize the carbon raw material at least one member selected from the consisting of, specifically to be one having a crystal structure of the synthesized optically isotropic petroleum pitch to the coke on the show through as a raw material, and may be one having a high crystallinity. The average particle diameter of primary particles in the powder of graphite and graphitized may be 2 ㎛ to 10 ㎛.
[46]
The negative electrode active material layer formed on a ceramic separation layer while preventing a short circuit between the positive and negative electrolytes can be passed, and can also provide a passage through which lithium ions can move actively included in the lithium secondary battery. Accordingly, the ceramic separation layers may perform the function as the separation membrane included in the conventional lithium secondary battery. Therefore, a lithium secondary battery comprising a lithium secondary battery negative electrode according to an example of the present invention may be a (unified stack cell) unified stack of cells that do not contain an extra membrane lithium secondary battery.
[47]
The ceramic isolation layer is an average diameter (D of 1 nm to 50 ㎛ as measured at the surface 50 may include a pore having a), the pores specifically, the average diameter (D of 10 nm to 10 ㎛ 50 can have a) and, more specifically, the average diameter (D of 10 nm to 5 ㎛ 50 can have). The average diameter (D of the pore 50 if) less than 1 nm, may electrolyte is smoothly passed through the ceramic separation layers, the mean diameter (D of the pore 50 if) not more than 50 ㎛, the insulating property between the positive electrode and the negative electrode It can exhibit stable.
[48]
In the present invention, the mean diameter (D 50 ) or average particle diameter (D 50 ) is defined as a particle diameter at 50% based on the particle size distribution. The average diameter or the average particle diameter is not particularly limited and may for example be measured using a laser diffraction method (laser diffraction method) or a scanning electron microscope (SEM) photograph. The laser diffraction method is generally possible to measure the particle diameter of approximately several mm from sub-micron (submicron) region, it is possible to obtain high reproducibility of the results and has a high degradation.
[49]
The ceramic separation layer may have a porosity (porosity) of 5% to 60%, and specifically have a porosity of 30% to 50%. If the ceramic separation layers have a porosity within the above range, the electrolyte solution can be smoothly, yet be able to pass through the ceramic separation layers exhibit an insulating property between the positive electrode and the negative electrode with a suitable mechanical strength of the ceramic separating layer in a stable manner.
[50]
The ceramic isolation layer is Al 2 O 3 , ZrO 2 , SiO 2 , TiO 2 , ZnO, BaTiO 3 , SrTiO 3 , CaCO 3 , CaO, CeO 2 , NiO, MgO, SnO 2 , Y 2 O 3 , Pb (Zr , Ti) O 3 (PZT), (Pb, La) (Zr, Ti) O 3 (PLZT), PB (Mg 3 Nb 2/3 ) O 3 -PbTiO 3 (PMN-PT) and hafnia (HfO 2) May include inorganic particles, at least one selected from the group consisting of, in particular Al 2 O 3 , ZrO 2 , SiO 2 , and TiO 2 may include one or more inorganic particles selected from the group consisting of. These inorganic particles may be included in powder form, 10 nm to an average particle size (D in 10 ㎛ 50 can have a), and specifically 50 nm to an average particle diameter of 5 ㎛ (D 50 ), more specifically 100 nm to 1 ㎛ with a mean particle size (D 50 may be one having a).
[51]
When the average particle diameter of the inorganic particles 10 nm or more, in the ceramic separation layers can be such that adequate porosity is the passage of an electrolytic solution formed by ensuring that the inorganic particles mungchiji to exert the appropriate dispersion, the average particle diameter of the inorganic particles If the 10 ㎛ or less, it is possible to form the ceramic separation layers so as to have an appropriate thickness.
[52]
The ceramic separation layer may be formed by a method of spraying or applying the material contained in the ceramic separation layer.
[53]
The ceramic separation layers are the inorganic and the particles may in addition include a binder, according to the exemplary embodiment of the present invention, the formation of the ceramic separation layers are for example the negative electrode of the inorganic particles and the water-based slurry or an organic slurry of the binder is mixed with a solvent wet (wet) of coating on the active material layer may be made of the application of the method.
[54]
The ceramic isolation layer is the inorganic particles and the binder of 99: may comprise 5 to 90: 10 weight ratio: 1 to weight ratio, in particular of 80: 20 to 95.
[55]
As the binder, if the binder used in the art and not particularly limited, for example, carboxymethyl cellulose (CMC), hydroxy propylene cellulose, diacetylene cellulose, polyacrylic acid, (meth) acrylate-based binders, polyvinyl alcohol, polyvinyl dichloride, ethylene (PTFE), polyvinylidene with polytetrafluoroethylene fluoride (PVdF), polyvinyl pyrrolidone, a conjugated diene-based binders, acrylonitrile-butadiene rubber, styrene butadiene rubber (SBR), ethylene-propylene- diene monomer (EPDM), sulfonated EPDM, or may already use a binder such as deugye binder.
[56]
The solvent may be exemplified by a water-based solvent such as water or an organic solvent such as N- methylpyrrolidone (NMP), dimethylformamide (DMF), acetone and dimethylacetamide.
[57]
The ceramic separation layer may have a thickness of 1 ㎛ to 30 ㎛, may have a specific 3 ㎛ to 20 ㎛, more specifically a thickness of 5 ㎛ to 10 ㎛. If the thickness of the ceramic separation layers less than 1 ㎛, the ceramic separation layers can exhibit the intensity of the appropriate degree, or less, the thickness of the ceramic separation layers 30 ㎛, to thin the total thickness of the electrode assembly including the cathode It can achieve a reduction in thickness of the lithium secondary battery comprising the same.
[58]
The lithium secondary battery comprising a lithium secondary battery negative electrode according to an example of the present invention may be a (unified stack cell) unified stack of cells that do not contain an extra membrane lithium secondary battery. Accordingly, the present invention provides a lithium secondary battery arrangement comprises a lithium secondary battery negative electrode, and a positive electrode in accordance with an example of the present invention, the positive active material layer of the anode is in contact with a ceramic separating layer of the negative electrode.
[59]
A negative electrode and a positive electrode of the lithium secondary battery has been placed facing each other between the ceramic separation layers, since the ceramic isolation layer is carried out the separation membrane as a function according lithium secondary battery according to one embodiment of the invention includes a separate additional separator It may be not.
[60]
Figure 1 is a view schematically showing a cross section of a lithium secondary battery comprising a lithium secondary battery negative electrode according to an example of the present invention is shown schematically.
[61]
Referring to Figure 1, and a lithium secondary battery according to one embodiment of the present invention is a ceramic separation layer 120 is interposed between the cathode 100 and the anode 200, cathode 100 and anode 200, a ceramic separation sandwiching a layer 120 has negative electrode active material layer 110 and the cathode active material layer 210 are facing each other.
[62]
The cathode can be prepared by conventional methods known in the art, for example, is producing a negative active material slurry by mixing and stirring the additives such as the negative electrode active material and a binder and a conductive material, dried, and applying it onto the negative electrode current collector after it may be prepared by compression.
[63]
The binder may be used to maintain the formed article by the binder of the negative electrode active material particles, if the conventional binders used in slurry for the negative electrode active material is not particularly limited, for example, a non-aqueous binder, polyvinyl alcohol, carboxymethyl cellulose, hydroxyethyl propylene cellulose, diacetylene cellulose, polyvinyl chloride, polyvinyl pyrrolidone, tetrafluoroethylene can be used ethylene (PTFE), polyvinylidene fluoride (PVdF), polyethylene or polypropylene, etc., and water-based binder, an acrylic ronayi trill-butadiene rubber may be used, and any one or a mixture of two or more of those selected from the group consisting of acrylic rubber-butadiene rubber, styrene. Aqueous binders, economical, eco-friendly compared to the non-aqueous binder, and harmless to health of the operator, because the binder effect superior to the non-aqueous binder, the high capacity is available it is possible to increase the ratio of the same material suitable active material, is a water-based binder preferably from styrene-butadiene rubber may be used.
[64]
The binder may be included in more than 10% by weight of the total weight of the slurry for the negative electrode active material, specifically, it may be included as 0.1% to 10% by weight. Without the content of the binder, preferably less than 0.1% by weight, the effect of the binder used mimihayeo, not preferred is a fear that a suitable dose due to the relative content reduction in the active material body according to the increased binder content decreases and if it exceeds 10% by weight not.
[65]
Without causing chemical changes in the fabricated battery. Standing the conductive material so long as it has suitable conductivity not particularly limited, examples of the conductive material in the graphite, such as natural or artificial graphite; Acetylene black, Ketjen black, channel black, furnace black, lamp black, carbon black and thermal black; Conductive fibers such as carbon fibers and metallic fibers; Metal such as carbon fluoride, aluminum, nickel powder, powder; Conductive whiskers such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Or polyester may be a conductive material such as phenylene derivatives. For the conductive material for the negative electrode active material slurry was the total weight can be used in an amount of 1% to 9% by weight.
[66]
Negative electrode current collector used for the negative electrode in accordance with one embodiment of the present invention may be one having a thickness of 3 ㎛ to 500 ㎛. The anode current collector is, so long as it has suitable conductivity without causing chemical changes in the fabricated battery is not particularly limited, for example on the surface of copper, gold, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel surface-treated with carbon, nickel, titanium or silver, and aluminum-cadmium alloys. Further, to form fine irregularities on the surface may enhance the bonding strength between the negative electrode active material, films, sheets, foils, nets, porous structures, foams and non-woven fabrics or the like can be used in various forms.
[67]
[68]
The positive electrode may be prepared by conventional methods known in the art. For example, to manufacture a binder, a conductive agent, were prepared for and a dispersant mixture and stirred slurry was applied (coating) it to the current collector of a metal material and the positive electrode by a compression after drying, depending on the solvent, it is required for the positive electrode active material have.
[69]
The collector of the metallic material that is conductive, a high metal, without causing chemical changes in the fabricated battery in a voltage range of the battery of a metal with a slurry of the positive electrode active material can be easily adhered standing if having a high electrical conductivity particularly limited. it is not, for example, stainless steel, aluminum, nickel, titanium, sintered carbon, or aluminum or stearyl Reinforced less carbon, nickel on the surface of the steel, titanium and the like may be used as a surface treatment or the like. It is also possible to form fine irregularities on the current collector surface to increase the adhesion of the positive electrode active material. Collector is available in many forms films, sheets, foils, nets, porous structures, foams and non-woven fabrics, etc., and may be one having a thickness of 3 to 500 ㎛.
[70]
The positive electrode active material such as lithium cobalt oxide (LiCoO 2 ); Lithium nickel oxide (LiNiO 2 ); Li [Ni a Co b Mn c M 1 d ] O 2 (wherein, M 1 is Al, and any one or two or more of these elements is selected from the group consisting of Ga and In, 0.3≤a <1.0, 0 ≤b≤0.5, a 0≤c≤0.5, 0≤d≤0.1, a + b + c + d = 1); Li (Li e M 2 f-e-f ' M 3 f' ) O 2 - g A g , and (wherein, 0≤e≤0.2, 0.6≤f≤1, 0≤f'≤0.2, 0≤g≤0.2 , M 2Is Mn and, Ni, Co, Fe, Cr , V, Cu, Zn , and comprises at least one element selected from the group consisting of Ti, M 3 and is at least one element selected from the group consisting of Al, Mg and B , a is P, F, S, and at least one member selected from the group consisting of N) layer compound or one or more of the compound substituted with transition metals, and the like; Li 1 + h Mn 2 - h O 4 (wherein 0≤h≤0.33), LiMnO 3 , LiMn 2 O 3 , LiMnO 2 Li-Mn oxide and the like; Lithium copper oxide (Li 2 CuO 2 ); LiV 3 O 8 , V 2 O 5 , Cu 2 V 2O 7 , etc. of vanadium oxide; Formula LiNi 1 - i M 4 i O 2 (wherein, M 4 Ni site type lithium nickel oxide represented by a = Co, Mn, Al, Cu, Fe, Mg, B or Ga, 0.01≤i≤0.3); Formula LiMn 2 - j M 5 j O 2 (wherein, M 5 = Co, Ni, Fe, Cr, and Zn, or Ta, 0.01≤j≤0.1) or Li 2 Mn 3 M 6 O 8 (wherein, M 6 lithium-manganese composite oxide represented by = Fe, Co, Ni, Cu or Zn); Some of the formula LiMn Li is substituted with alkaline earth metal ion 2O 4 ; Disulfide compounds; LiFe 3 O 4 , Fe 2 (MoO 4 ) 3 While the like, but is not limited to these.
[71]
The solvent for forming the positive electrode is NMP (N- methylpyrrolidone), DMF (dimethylformamide), acetone, and the organic solvent or water and the like, such as dimethylacetamide, these solvents alone or in combinations of two or more to be used in combination. The amount of the solvent is sufficient enough to be applied in consideration of the thickness of the slurry, the production yield and soluble dispersing the positive electrode active material, binder, conductive material.
[72]
The binder include polyvinylidene fluoride-acrylonitrile-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinylidene fluoride (polyvinylidenefluoride), polyacrylonitrile (polyacrylonitrile), polymethyl methacrylate (polymethylmethacrylate), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM , styrene-butadiene rubber (SBR), fluorine rubber, polyacrylic acid (polyacrylic acid) and those of the hydrogen replaced with Li, Na, or Ca, such as a polymer, or a variety of binder polymers, such as various copolymers can be used.
[73]
So long as it has suitable conductivity without causing chemical changes in the fabricated battery. The conductive material is not particularly limited, for example, graphite such as natural graphite or artificial graphite; Acetylene black, Ketjen black, channel black, wave Ness black, carbon black and lamp black and thermal black; Conductive fibers such as carbon fibers and metallic fibers; Metal tubes, such as carbon nanotubes; Metal powders such as carbon, aluminum, nickel powder fluoro; Conductive whiskers such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Poly is a conductive material such as phenylene derivative may be used. 1 with respect to the conductive material by weight of the total positive electrode slurry may be used in an amount of from% to 20% by weight.
[74]
The dispersant may be an organic dispersant such as a water-based dispersant, or N- methyl-2-pyrrolidone.
[75]
A lithium salt which can be included as an electrolyte used in the present invention can be used without limitation, those which are commonly used in a lithium secondary battery electrolyte, for example the lithium salt of the anion is F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , BF 4 - , ClO 4 - , PF 6 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 -, (CF 3) 5PF -, (CF 3) 6P -, CF 3SO 3 -, CF 3CF 2SO 3 -, (CF 3SO 2) 2N -, (FSO 2) 2N -, CF 3CF 2(CF 3) 2CO -, (CF 3SO 2) 2CH -, (SF 5) 3C -, (CF 3SO 2) 3C -, CF 3(CF 2) 7SO 3 -, CF 3CO 2 -, CH 3CO 2 -, SCN - 및 (CF 3CF 2SO 2 ) 2 N - may be any one selected from the group consisting of.
[76]
Electrolyte for use in the present invention and the like used in manufacturing a lithium secondary battery possible organic liquid electrolyte, an inorganic liquid electrolytes, solid polymer electrolytes, gel polymer electrolytes, solid inorganic electrolytes, molten-type inorganic electrolyte, but are not limited to, no.
[77]
The outer shape of the lithium secondary battery of the present invention Although there is no particular limitation, may be a cylindrical shape using a can, prismatic, pouch (pouch) type or a coin (coin) type.
[78]
The lithium secondary battery according to the present invention can also be preferably used as not only can it be used in a battery cell used as a power source for small devices, in the middle- or large-sized battery module including a plurality of battery cell unit cells.
[79]
Preferred examples of the middle- or large-sized devices are an electric vehicle, hybrid electric vehicles, plug-in may include a hybrid electric car and electric power storage system or the like, but is not limited to these.
Mode for the Invention
[80]
Example
[81]
Hereinafter, one described in the examples and experimental example in more detail to illustrate the present invention in detail, the present invention is not limited by these examples and experimental examples. Examples according to the present invention can be modified in many different forms and the scope of the invention is not to be construed as limited to the embodiments set forth herein. Embodiments of the present invention are provided to more fully illustrate the present invention to those having ordinary skill in the art.
[82]
[83]
Example 1
[84]

[85]
A negative electrode with an average particle size (D 50 ) graphite 96% by weight of 15 ㎛ artificial, Denka black (conductive agent), 1% by weight of SBR (agent) 2% by weight, and CMC (thickener), the negative electrode by the addition of 1% by weight in water to prepare a slurry. The coated the prepared anode slurry in a thickness of 65 ㎛ on one surface of the copper collector, and drying and rolling the electrode density to 1.72 g / cc was then prepared for the negative electrode was punched into a predetermined size. The artificial graphite may be assembled with secondary particles, using a graphite the coked catalyst is a block consisting of a graphite graphitization process at least 3,000 ℃.
[86]
On the surface with the active material layer of the negative electrode prepared in the above are formed, the average particle diameter (D 50 ) Al of 500 nm 2 O 3 for the 5 g and carboxymethyl cellulose 2 g a solution mixed in 100 mL of water using a PD Mixer and then uniformly mixed, and sprayed in the die at a rate of a slot die coater using a 10 m per minute, the average diameter (D a 10 ㎛, thickness and porosity of 50 to form a ceramic isolation layer having a) 200 nm.
[87]
[88]
Example 2
[89]

[90]
A cathode, and is, in Example 1 and the same method except that the formed such that a ceramic separation layer 20 ㎛ thickness was prepared.
[91]
[92]
Example 3
[93]

[94]
A cathode, and is, in Example 1 and the same method except that the formed such that a ceramic separation layer 30 ㎛ thickness was prepared.
[95]
[96]
Example 4
[97]
Except that a rolled to be 1.81 g / cc density of the electrode, a negative electrode was prepared as in Example 1 and the same method.
[98]
[99]
Example 5
[100]
Except that a rolled such that the electrode density of 1.79 g / cc, a negative electrode was prepared as in Example 1 and the same method.
[101]
[102]
Example 6
[103]
Except that a rolled to be 1.76 g / cc density of the electrode, a negative electrode was prepared as in Example 1 and the same method.
[104]
[105]
Example 7
[106]
Except that a rolled to be 1.69 g / cc density of the electrode, a negative electrode was prepared as in Example 1 and the same method.
[107]
[108]
Example 8
[109]

[110]
The average particle diameter (D 50 ), the artificial graphite of 96% by weight of 15 ㎛, Denka black (conductive agent), 1% by weight of SBR (agent) 2% by weight, and CMC (thickener) was added to 1% by weight in water, a first negative electrode slurry the other hand, the average particle diameter (D produced a 50 addition of) artificial graphite of 96% by weight of 4 ㎛, Denka black (conductive agent), 1% by weight of SBR (agent) 2% by weight, and CMC (thickener) 1% by weight in water to manufacture a second negative electrode slurry.
[111]
The thus prepared second negative electrode slurry on the coated surface of the first negative electrode slurry, the coating, the prepared first cathode slurry to a 60 ㎛ thickness on one surface of the copper collector and dried rolled to 1.72 g / cc, and then, coating with a thickness of 5 ㎛ and dried was prepared and then, the negative electrode was punched into a predetermined size rolled to 1.72 g / cc.
[112]
The first artificial graphite of the negative electrode slurry may be assembled to the secondary particles, and the graphitization step powdery graphitized graphite made in more than 3,000 ℃, the main composition is made up of needle-based coke, artificial and of the second negative electrode slurry graphite assembly is a secondary particle and a graphite block composed of the graphitization process in the more than 3,000 ℃ by use of a catalyst, the main components are composed of needle-based coke.
[113]
On the surface with the active material layer of the negative electrode prepared in the above are formed, the average particle diameter (D 50 ) Al of 500 nm 2 O 3 for the 5 g and carboxymethyl cellulose 2 g a solution mixed in 100 mL of water using a PD Mixer and then uniformly mixed, and sprayed in the die at a rate of a slot die coater using a 10 m per minute, the average diameter (D a 10 ㎛, thickness and porosity of 50 to form a ceramic isolation layer having a) 200 nm.
[114]
[115]
Comparative Example 1
[116]

[117]
As a synthetic graphite, secondary and assembled into particles, and the graphitization step powdery graphitized graphite made in more than 3000 ℃, the main composition is the average particle diameter (D consisting of a mosaic based coke 50 using a) of 15 ㎛ artificial graphite and is the cathode as described in example 1 and the same method was prepared except that.
[118]
[119]
Comparative Example 2
[120]

[121]
A cathode, and, the Comparative Example 1 and the same method except for forming a ceramic separation layer that are 20 ㎛ thickness was prepared.
[122]
[123]
Comparative Example 3
[124]

[125]
A cathode, and, the Comparative Example 1 and the same method except for forming a ceramic separation layer that are 30 ㎛ thickness was prepared.
[126]
[127]
Comparative Example 4
[128]

[129]
As artificial graphite, the second is incorporated into particles and a powder of graphite and graphitized the graphitization process was at least 3,000 ℃, the main composition is the average particle diameter (D consisting of a mosaic based coke 50 was used to form) for 4 ㎛ artificial graphite except for is the cathode as described in example 1 and the same method was prepared.
[130]
TABLE 1
Electrode density (g / cc) The thickness of the ceramic separation layers (㎛)
Example 1 1.72 10
Example 2 1.72 20
Example 3 1.72 30
Example 4 1.81 10
Example 5 1.79 10
Example 6 1.76 10
Example 7 1.69 10
Example 8 1.72 / 1.72 10
Comparative Example 1 1.72 10
Comparative Example 2 1.72 20
Comparative Example 3 1.72 30
Comparative Example 4 1.72 10

[131]
Experimental example 1: Pellet density and degree of orientation negative evaluation by measuring the density of pellets of the negative electrode slurry prepared in Example 1 to 8 and Comparative Examples 1 to 4 are shown in Table 2. The results are.
[132]
Examples 1 to 8 and Comparative Example 1 respectively put in a bowl the negative electrode slurry made of an aluminum foil prepared in 1-4, and completely drying it in an oven 110 ℃. After between the dried slurry powder Muller finely using a bowl and pestle, and then chyeojun poles using a 250 mesh sieve (mesh sieve), by metering a 1 g into a pellet jig, 1,000 kg / m 3 was added to the pressure the pellet was prepared. After the finished pellet slurry was allowed to stand for 6 hours, it was weighed and the thickness of the pellets. At this time, the pellet density was calculated by measuring the thickness and weight.
[133]
In Examples 1 to 8 and Comparative Examples 1 and evaluated in the X- ray diffraction (XRD) analysis the degree of orientation of the manufactured negative electrode 4 the results are shown in Table 2 below.
[134]
Examples 1 to 8 and Comparative Example 1 respectively put in a bowl the negative electrode slurry made of an aluminum foil prepared in 1-4, and completely drying it in an oven 110 ℃. After between the dried slurry powder Muller finely using a bowl and pestle, and then chyeojun poles using a 250 mesh sieve (mesh sieve), by metering a 1 g into a pellet jig, the density of the pellet was 1.6 g / cc such that the pellets were produced by applying pressure. After Fill the pellets prepared above in Fig XRD equipment only holes made to be given by pressing a slide glass to a flat surface, and the XRD analysis.

WE Claims

Negative electrode active material layer; And a ceramic separation layer formed on the anode active material layer, the negative electrode active material layer had an arithmetic average surface roughness (Ra) 0.01 ㎛ to 0.3 ㎛, the ceramic separation layer has a thickness of 1 ㎛ to 30 ㎛, The lithium secondary battery anode.
[Claim 2]
The method of claim 1, wherein the negative active material for a lithium secondary battery negative electrode comprising a graphite-based active material.
[Claim 3]
Claim 2 wherein the negative electrode active material layer is 1,000 kg / m to 3 when pressure is applied and the density of the pellet formed of the negative electrode slurry is not less than 1.7 g / cc, a lithium secondary battery negative electrode.
[Claim 4]
The method of claim 3, wherein the negative electrode active material layer is oriented in a negative electrode active material measured by XRD when the density is g 1.6 / cc (I 004 / I 110 ) of 50 or more, a lithium secondary battery negative electrode.
[Claim 5]
The method of claim 1, wherein the negative electrode active material layer Average particle diameter (D 7 of ㎛ to 30 ㎛ 50 , a lithium secondary battery negative electrode comprising a negative active material having an).
[Claim 6]
According to claim 1, wherein the ceramic separation layer is a lithium secondary battery negative electrode having a thickness of 3 ㎛ to 15 ㎛ on.
[Claim 7]
The method of claim 1, wherein the ceramic isolation layer is an average particle diameter (D 10 of 10 nm to ㎛ 50 , a lithium secondary battery negative electrode comprising an inorganic particle having a).
[Claim 8]
The method of claim 1, wherein the ceramic isolation layer is an average diameter (D of 1 nm to 50 ㎛ 50 , a lithium secondary battery negative electrode comprising a pore having a).
[Claim 9]
The method of claim 1, wherein the ceramic separation layer is a lithium secondary battery negative electrode having a degree of from 5 to 60% pores.
[Claim 10]
The method of claim 1, wherein the ceramic isolation layer is Al 2 O 3 , ZrO 2 , SiO 2 , TiO 2 , ZnO, BaTiO 3 , SrTiO 3 , CaCO 3 , CaO, CeO 2 , NiO, MgO, SnO 2 , Y 2 O 3 , Pb (Zr, Ti) O 3 (PZT), (Pb, La) (Zr, Ti) O 3 (PLZT), PB (Mg 3 Nb 2/3 ) O 3 -PbTiO 3 (PMN-PT) and hafnia (HfO 2), A lithium secondary battery negative electrode comprising at least one selected from the group consisting of.
[Claim 11]
The method of claim 1, wherein the ceramic isolation layer is Al 2 O 3 , ZrO 2 , SiO 2 , and TiO 2 , a lithium secondary battery negative electrode comprising at least one selected from the group consisting of.
[Claim 12]
The method of claim 1, wherein the negative electrode active material layer Average particle diameter of the first cathode active material layer and the second negative electrode active material layer, and a second negative electrode active material layer formed on the first negative electrode active material layer is 0.03 ㎛ to 7 ㎛ ( D 50 ), a lithium secondary battery negative electrode comprising a negative active material having a.
[Claim 13]
The method of claim 12 wherein the first cathode active material layer Average particle size (D in 5 ㎛ to 30 ㎛ 50 , a lithium secondary battery negative electrode comprising a negative active material having an).
[Claim 14]
The method of claim 1, wherein the negative electrode coating portion is the arithmetic mean surface roughness (Ra) of 0.05 and ㎛ to 0.25 ㎛, average particle size (D in 10 ㎛ to 25 ㎛ 50 , a lithium secondary battery negative electrode comprising a negative active material having an) .
[Claim 15]
The method of claim 1, wherein the ceramic separation layer has a thickness of 5 to 10 ㎛ ㎛, the average particle diameter (D of 200 nm to 800 ㎛ 50 comprising inorganic particles having a) a lithium secondary battery negative electrode.
[Claim 16]
A cathode, and an anode according to claim 1, and a lithium secondary battery positive electrode active material layer disposed on the anode is in contact with a ceramic separating layer of the negative electrode.