(19)
(11)EP 3 561 922 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
04.11.2020 Bulletin 2020/45

(21)Application number: 19185744.0

(22)Date of filing:  08.12.2017
(51)International Patent Classification (IPC): 
H01M 4/505(2010.01)
H01M 4/587(2010.01)
H01M 10/0525(2010.01)
H01M 4/02(2006.01)
H01M 4/131(2010.01)
H01M 4/525(2010.01)
H01M 4/62(2006.01)
H01M 4/133(2010.01)
H01M 4/583(2010.01)

(54)

LITHIUM ION SECONDARY BATTERY

LITHIUM-IONEN-SEKUNDÄRBATTERIE

BATTERIE SECONDAIRE AU LITHIUM-ION


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 06.09.2017 CN 201710795465

(43)Date of publication of application:
30.10.2019 Bulletin 2019/44

(62)Application number of the earlier application in accordance with Art. 76 EPC:
17206221.8 / 3454397

(73)Proprietor: Contemporary Amperex Technology Co., Limited
Jiaocheng District Ningde City, Fujian 352100 (CN)

(72)Inventors:
  • SHEN, Rui
    Ningde City, Fujian, 352100 (CN)
  • MA, Jianjun
    Ningde City, Fujian, 352100 (CN)
  • HE, Libing
    Ningde City, Fujian, 352100 (CN)

(74)Representative: Viering, Jentschura & Partner mbB Patent- und Rechtsanwälte 
Am Brauhaus 8
01099 Dresden
01099 Dresden (DE)


(56)References cited: : 
EP-A1- 3 032 620
KR-A- 20140 098 424
JP-A- 2015 164 143
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    TECHNICAL FIELD



    [0001] The present application relates to the field of batteries, and more particularly, to a lithium ion secondary battery.

    BACKGROUND



    [0002] With the growing popularity of electric vehicles, the requirements of the battery are stricter, such as the battery is required to be both small and light and must also have high capacity, long cycle and stable performance. To this end, the technical persons have made a variety of efforts from the cathode and anode, electrolytes of battery and so on.

    [0003] For example, with respect to positive active material for a battery, NCM has a higher capacity and density compared to lithium ion phosphate(LFP). Therefore, a cell using NCM has a higher energy density. However, unlike LFP that the volume thereof will shrinkage when it charges, the volume of NCM will expand when it charges; the expansion force will damage the interface between anode and cathode, and cause the battery failure. Therefore, despite the higher energy density, the cycle life of ternary battery is often worse than that of lithium ion phosphate battery.

    [0004] JP2015164143 discloses a negative material for a nonaqueous electrolyte secondary battery, wherein the negative material at least comprises: a graphite particle (A) having a surface separation (d002) in a 002 plane of 3.37 Å or less and an average circularity of 0.9 or more in an X-ray wide-angle diffraction method; and a carbon material (B) having a surface separation (d002) in a 002 plane of 3.37 Å or less in an X-ray wide-angle diffraction method. Such mixed carbon material used as a negative electrode of a nonaqueous secondary battery exhibits the characteristics of small irreversible capacity.

    [0005] EP3032620A1 relates to a negative electrode material for a lithium ion battery, made of a composite material comprising silicon-containing particles, artificial graphite particles and a carbon coating layer, wherein the silicon-containing particles are silicon particles having a SiOx layer (0<x≤2) on a particle surface, have an oxygen content ratio of 1 mass% or more and 18 mass% or less, and mainly comprise particles having a primary particle diameter of 200 nm or less; and the artificial graphite particles have a scale-like shape. By using the negative electrode material, a lithium ion battery having a high capacitance and excellent charge-discharge cycle characteristics can be produced.

    [0006] KR20140098424 discloses a positive active material for a secondary battery with improved low-temperature properties, wherein the positive active material comprises a bimodal lithium nickel-manganese-cobalt oxide consisting of small particles and large particles, which have different average particle sizes, and a monomodal olivine lithium iron phosphate, wherein the difference in content of Ni, Mn and Co in the small particles and the corresponding content of Ni, Mn and Co in the large particles is 2mol% or less, or the content of Ni in the small particles is 1-20mol% more than the content of Ni in the large particles.

    [0007] Therefore, it is still a great challenge to match right positive active material with right negative active material in order to improve battery performance.

    [0008] In view of this, it is necessary to provide a battery with good performance.

    SUMMARY



    [0009] An object of the present application is to provide a lithium ion secondary battery having comprehensive and balanced performance.

    [0010] A further object of the present application is to provide a lithium ion secondary battery capable of providing both long cycle life and high energy density without sacrificing the energy density of the batteries.

    [0011] The inventors have experimented with a large number of experiments to surprisingly find that a particular type of positive active material and negative active material for battery can be combined to improve the cycle life and energy density of the lithium ion secondary battery at the same time.

    [0012] In particular, the present application provides a lithium ion secondary battery comprising a cathode, an anode, a separator and an electrolyte, according to the independent claim 1,
    wherein the anode comprises a negative current collector and a negative material layer, wherein the negative material layer comprises graphite having a graphitization degree of 94% to 98% and an average particle size D50 of 6µm to 18µm as negative active material.

    [0013] Compared with the prior art, the lithium ion secondary battery provided by the present application can have both long cycle life and high energy density by using a specific positive and negative active material.

    [0014] The present application also relates to a method for producing the lithium ion secondary battery, not forming part of the current invention, comprising:
    1. 1) preparing a cathode by using a positive active material with formula LixNiaCobMcO2, wherein M is at least one selected from the group consisting of Mn and Al, 0.95 ≤x≤ 1.2, 0 <a <1, 0 <b <1, 0 <c <1 and a + b + c = 1;
    2. 2) preparing an anode by using graphite having a graphitization degree of 94% to 98% and an average particle size D50 of 6µm to 18µm as negative active material; and
    3. 3) assembling the cathode prepared in step 1) and the anode prepared in step 2) into a battery.

    DETAILED DESCRIPTION



    [0015] The present application will be described in further details with reference to the embodiments and the accompanying drawings in order to make the objects, the technical solutions and the advantageous technical effects of the present application clearer. It is to be understood, however, that the embodiments of the application are merely for the purpose of explaining the application and are not intended to be limiting the application, and that the embodiments of the application are not limited to the embodiments given in the specification. The experimental conditions not specified in the examples are given according to conventional conditions, or according to the conditions recommended by the material supplier.

    [0016] The present application provides a lithium ion secondary battery comprising a cathode, an anode, a separator and an electrolyte,
    wherein the cathode comprises a positive current collector and a positive material layer, wherein the positive material layer comprises a positive active material with formula LixNiaCobMeO2, M is at least one selected from the group consisting of Mn and Al, 0.95≤ x≤ 1.2, 0<a <1, 0 <b <1, 0 <c <1 and a + b + c = 1;
    wherein the anode comprises a negative current collector and a negative material layer, wherein the negative material layer comprises graphite having a graphitization degree of 94% to 98% and an average particle size D50 of 6µm to 18µm as negative active material.

    [0017] The inventors believe that the graphite having a graphitization degree of 94% to 98% and an average particle diameter of D50 of 6µm to 18µm can form a high elastic structure inside the material, and has a higher elasticity than the conventional graphite material. When charging the positive active material will expand, and this will result in that the extrusion force to the anode increases. However, the use of the above-mentioned high elastic graphite will make the anode has a strong restoring ability after bearing a large pressure, so that the contact surface between the anode material remains intact, to avoid material interface damage and stripping phenomenon caused by the expansion, which will improve the battery cycle performance without loss of energy density. However, the above explanation is provided for the purpose of facilitating to understand the principles of the present application by those skilled in the art and is not to be construed as limiting the application. The present application does not preclude the possibility that other principles may be made with the development of technology.

    [0018] The inventors have further found that the higher the graphitization degree of the graphite is, the higher the battery capacity will be, but a too high graphitization degree will lead to the narrowing of the interlayer distance of the graphite, and the volume change caused by the lithium ion deintercalation during charging and discharging will be great, which will impact the stability of SEI layer. If the graphitization degree is too low, the crystallinity of graphite is low, and lattice defects will be more, thus in the process of cycling side effects are prone to occur and it will lead to capacity attenuation. Through a large number of experiments, the inventors found that the graphitization degree from 94% to 98% is just right, preferably from 94% to 96%.

    [0019] The inventors have further found that when the D50 of the graphite is more than 18µm, it will cause the number of the stacking layers of the particles less, and it is difficult to form an elastic structure. When the D50 is less than 6µm, the bonding force between materials is too weak, thus the adhesion to the electrode plate will be poor, during the cycle stripping phenomenon is prone to occur and it will lead to capacity attenuation. Therefore, the graphite should have an average particle size D50 of 6µm to 18µm, preferably 6µm to 12µm.

    [0020] In order to further improve rate performance, the surface of the graphite may also have a coating layer. The coating layer is usually an amorphous carbon, for example, at least one selected from the group consisting of carbon black, coke, soft carbon and hard carbon. The content of the amorphous carbon relative to the total weight of the electrode material is generally from 2% to 13%, preferably from 5 to 10%. In some embodiments, the amorphous carbon is obtained by (high temperature) carbonization of at least one material selected from the group consisting of polyvinyl butyral, bitumen, furfural resin, epoxy resin or phenolic resin.

    [0021] The lithium ion secondary battery which comprises specific positive material and specific negative material above-mentioned can be prepared by a method known in the field, such as following:

    1.Preparation of cathode



    [0022] In general, the positive active material, the conductor, the binder are mixed in a certain weight ratio, then the solvent is added and the mixture is stirred under the action of a vacuum stirrer into a uniform transparent state to obtain a positive material slurry; coat the positive current collector with the positive material slurry; then dry it and slit to obtain a cathode.

    [0023] The positive active material used in the present application is LixNiaCobMcO2, wherein M is at least one selected from the group consisting of Mn and Al, 0.95 ≤x≤ 1.2, 0<a<1, 0<b<1, 0<c<1 and a+ b + c = 1. When M is Mn, the formula of the material is abbreviated as NCM; when M is Al, the formula of the material is abbreviated as NCA. The materials can be purchased from suppliers.

    [0024] Specifically, the positive active material may be at least one selected from the group consisting of LiNi0.33Co0.33Mn0.33O2, LiNi0.5Co0.2Mn0.3O2, LiNi0.5Co0.25Mn0.25O2, LiNi0.6Co0.2Mn0.2O2, LiNi0.8Co0.1Mn0.1O2, LiNi0.85Co0.1Mn0.05O2 and LiNi0.8Co0.15Al0.05O2.

    [0025] In a preferred embodiment of the present application, the content of the positive active material is 94% to 98% by weight based on the total weight of the positive material layer.

    [0026] In some embodiments of the present application, the positive active material may also be doped with at least one element selected from the group consisting of Al, Zr, Ti, B, Mg, V, Cr, F, in order to further improve the battery performance.

    [0027] In some embodiments of the present application, forming a coating layer on the outside of the crystal of the positive active material may further improve the battery performance, and the coating layer may contain for example at least one of Al, Zr, Ti and B elements.

    2.Preparation of anode


    1) preparing the negative material



    [0028] In the present application, a graphite having a graphitization degree of 94% to 98% and an average particle size D50 of 6µm to 18µm is used as the negative active material. In the present application, the "graphite" has the meaning which is well understood by those skilled in the art, and is a carbon material suitable as the battery negative material which mainly has the form of a graphite sheet in the interior. The graphite may be natural graphite, artificial graphite, or a mixture thereof. The graphite used in the present application having a graphitization degree of 94% to 98% and an average particle size D50 of 6µm to 18µm can be prepared, for example, by the following method:
    1. (A) crushing the calcined petroleum needle-coke or calcined coal needle-coke to obtain the raw materials having an average particle size of 5-20µm;
    2. (B) subjecting the raw material obtained in step (A) to a shaping treatment and then subjecting to a classification treatment to adjust the particle size distribution of the raw material (preferably, large particles having a particle size larger than D90 and small particles having a particle size smaller than D10 are removed);
    3. (C) sieving the raw material obtained in step (B) and then subjecting it to high-temperature graphitization, for example, in an Acheson graphitizing furnace at a temperature of, for example, 2800°C to 3250°C (preferably 2850°C to 3200°C);
    4. (D) sieving and demagnetizing the material obtained in step (C), to obtain the desired negative material.


    [0029] The shaping treatment in step (B) is a conventional treatment method in the preparation process of artificial graphite, which is well known to those skilled in the art and can be carried out by using any shaping machine or other shaping device commonly used in the art. The classification treatment in step (B) can be carried out by using a classification screen (sieving method), a gravity classifier, a centrifugal separator or the like. Optionally, after step (C)the coating carbonization step may be carried out prior to step (D), i.e. the product obtained in step (C) is mixed with at least one material selected from the group consisting of polyvinyl butyral, bitumen, furfural resin, epoxy resin or phenolic resin and subjected to high-temperature carbonization treatment. The temperature of the carbonization treatment is, for example, 900-1500°C, for example 1000-1400°C or 1100-1300°C.

    [0030] Alternatively, the present application may also use a natural graphite or commercially available graphite having a graphitization degree of 94% to 98% and an average particle size D50 of 6µm to 18µm.

    [0031] The graphitization degree of the graphite can be determined by methods known in the field, for example by X-ray diffractometer (reference, for example, Qian Chongliang et al., "Graphitization Measurement of Carbon Material by X-ray Diffraction" , Journal of Central South University of Technology, Vol. 32, No. 3, June 2001).

    [0032] The average particle size D50 of the graphite can be conveniently determined by using a laser particle size analyzer (e.g., Malvern Master Size 2000).

    2) Assembly of the anode



    [0033] In general, the negative active material, the thickener, the binder are mixed at a certain weight ratio; then the solvent is added to obtain the negative electrode slurry; then coat the negative current collector with the negative electrode slurry; then dry it and slit to obtain an anode.

    [0034] In a preferred embodiment of the present application, the content of the negative active material is 94% to 98% by weight based on the total weight of the negative material layer.

    3. Preparation of electrolyte



    [0035] As a non-aqueous electrolyte, a lithium salt solution dissolved in an organic solvent is usually used. Lithium salts are, for example, inorganic lithium salts such as LiClO4, LiPF6, LiBF4, LiAsb6, LiSbF6; or organic lithium salts such asLiCF3SO3, LiCF3CO2, Li2C2F4(SO3)2, LiN(CF3SO2)2, LiC(CF3SO2)3, LiCnF2n+1SO3(n≥2). The organic solvent used in the non-aqueous electrolyte is, for example, a cyclic carbonate such as ethylene carbonate, propylene carbonate, butylene carbonate and vinylene carbonate; or a chain carbonate such as dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; or a cyclic ester such as methyl propionate;or a chain ester such as γ-butyrolactone; or a chain ether such as dimethoxyethane, diethyl ether, diethylene glycol dimethyl ether and triethylene glycol dimethyl ether; or a cyclic ether such as tetrahydrofuran and 2-methyltetrahydrofuran; or nitriles such as acetonitrile and propionitrile; or a mixture of these solvents.

    [0036] For example, ethylene carbonate (EC), methyl ethyl carbonate (EMC) and diethyl carbonate (DEC) were mixed according to a certain volume ratio, and then the sufficiently dried lithium salt LiPF6 was dissolved in a mixed organic solvent to prepare an electrolyte.

    4. Separator



    [0037] There is no special requirement for the separator. In particularly, the separator may be selected from a polyethylene film, a polypropylene film, a polyvinylidene fluoride film, and a multilayer composite film thereof, depending on the actual requirements.

    5.Preparation of battery



    [0038] Put the separator between the cathode and anode, then winding, jelly roll insertion, electrolyte injection and so on to obtain the lithium ion battery.

    [0039] The advantageous effects of the present application will be further described below with reference to the following examples.

    1. Material preparation and battery assembly



    [0040] 
    1. (1) The preparation of a cathode: LiNi0.6Co0.2Mn0.2O2, SuperP (conductive agent), PVDF (binder) were mixed at a mass ratio of 97: 1: 2, then a solvent was added. The mixture was stirred in a vacuum mixer into a uniform and transparent system, to obtain the positive electrode slurry. The positive electrode slurry was uniformly coated on the positive current collector aluminum foil; then the aluminum foil was dried at room temperature and then transferred to the oven for drying, and then the cathode was obtained by cold pressing and cutting.
    2. (2)The preparation of an anode: artificial graphite anode active material samples were taken, and the particle size of the sample was measured by using Malvern Master Size 2000 laser particle size analyze, and the graphitization degree of the sample was measured by using X-ray diffractometer. The test results can be found from Table 1. The artificial graphite negative active material, sodium carboxymethyl cellulose (thickener) and SBR (styrene-butadiene rubber binder) were mixed at a mass ratio of 97: 1.2: 1.8, and deionized water was added, then under the action of a vacuum stirrer a negative electrode slurry was obtained. The negative electrode slurry was uniformly coated on the negative current collector copper foil; the copper foil was dried at room temperature and then transferred to the oven for drying, and then the anode was obtained by cold pressing and cutting.
    3. (3)The preparation of an electrolyte: Ethylene carbonate (EC), methyl ethyl carbonate (EMC) and diethyl carbonate (DEC) were mixed at a volume ratio of 3: 6: 1, followed by dissolving the fully dried lithium salt LiPF6 into a mixed organic solvent at a concentration of 1 mol/L to prepare an electrolyte.
    4. (4) Separator: 12 micron PP/PE composite isolation film was used.
    5. (5)The preparation of the full battery: the cathode, the separator, the anode were stacked in order, so that the separator was segregated between the cathode and anode, and then the stack was wound to obtain a bare cell; the bare cells were placed in the outer packaging shell. The prepared electrolyte was poured into dried bare cells, and the lithium ion battery was obtained by vacuum packaging, standing, chemical treatment, shaping and the like.

    2.The cycle performance:



    [0041] At 25°C, the battery was firstly charged and discharged as follows: constant current charging and constant voltage charging with a constant current of 1C until the voltage upper limit of 4.2V, then constant current discharging with a constant current of 1C until the final voltage of 2.8V, recording the discharge capacity of the first cycle. Charging/discharging cycles were done in such way.

    [0042] Cycle capacity retention rate = (discharge capacity of the nthcycle/discharge capacity at the first cycle) × 100

    Examples 2-12 (Example 5 is not in accordance with the invention)



    [0043] Example 1 was repeated using different positive active materials and negative active materials. The parameters of the materials and the battery performance data were summarized in Table 1.

    Comparative Examples 1-4



    [0044] Example 1 was repeated using different positive active materials and negative active materials. The parameters of the materials and the battery performance data were summarized in Table 1.
    Table 1
    Comparative example/ExampleGraphitiza tion degreeof negative electrodeAverage particle size of the negative material (µm)Positive materialDopant of the positive materialCoating of the positive materialCycle capacity retention rate of 500th cycleCycle life (attenua tion to 80%)
    Example 1 94% 6 LiNi0.6Co0.2Mn0.2O2 No No 95.70% 2543
    Example 2 94% 8 LiNi0.6Co0.2Mn0.2O2 No No 95.50% 2422
    Example 3 94% 12 LiNi0.6Co0.2Mn0.2O2 No No 95.10% 2193
    Example 4 94% 18 LiNi0.6Co0.2Mn0.2O2 No No 94.50% 1998
    Example 5 (Comparative) 92% 8 LiNi0.6Co0.2Mn0.2O2 No No 95.80% 2594
    Example 6 96% 8 LiNi0.6Co0.2Mn0.2O2 No No 95.20% 2234
    Example 7 98% 8 LiNi0.6Co0.2Mn0.2O2 No No 94.10% 1832
    Example 8 94% 8 LiNi0.5Co0.2Mn0.3O2 No No 95.80% 2591
    Example 9 94% 8 LiNi0.5Co0.25Mn0.25O2 No No 95.65% 2605
    Example 10 94% 8 LiNi0.33Co0.33Mn0.33O2 No No 96.40% 3052
    Example 11 94% 8 LiNi0.6Co0.2Mn0.2O2 B No 95.70% 2556
    Example 12 94% 8 LiNi0.6Co0.2Mn0.2O2 B Al 96.10% 2843
    Comparative example 1 94% 4 LiNi0.6Co0.2Mn0.2O2 No No 92.10% 1105
    Comparative example 2 94% 20 LiNi0.6Co0.2Mn0.2O2 No No 89.10% 712
    Comparative example 3 88% 8 LiNi0.6Co0.2Mn0.2O2 No No 88.90% 1030
    Comparative example 4 99% 18 LiNi0.6Co0.2Mn0.2O2 No No 88.30% 604


    [0045] Test result analysis:
    1. 1. As can be seen from the analysis of Examples 1-4 and Comparative Examples 1-2:
      When the D50 of the negative material was not within the scope of the present application, the battery cycle performance was remarkably reduced. In Examples 1-4, it was found that when the graphitization degree was constant, the battery cycle performance was gradually decreased with the increase of the average particle size of the material, preferably in the range of 6-12µm.
    2. 2.As can be seen from the analysis of Examples 2, 5-7 and Comparative Examples 3-4:
      When the graphitization degree of the negative material was not within the scope of the present application, the battery cycle performance was remarkably deteriorated. In Examples 2 and 5-7, it can be seen that when the average particle size of the material was constant, the battery cycle performance was gradually decreased with the increase of graphitization degree, preferably in the range of 94% to 96%.
    3. 3. As can be seen from the analysis of Examples 2 and 11-12,
      When the positive material was doped and/or coated, the cycle performance of the battery can be further improved.


    [0046] It will be apparent to those skilled in the art that the present application may be modified and varied in accordance with the above teachings. Accordingly, the present application is not limited to the specific embodiments disclosed and described above, and modifications and variations of the present application are intended to be included within the scope of the claims of the present application. In addition, although some specific terminology is used in this specification, these terms are for convenience of illustration only and are not intended to limit the present application in any way.


    Claims

    1. A lithium ion secondary battery comprising a cathode, an anode, a separator and an electrolyte, wherein the anode comprises a negative current collector and a negative material layer, and the negative material layer comprises graphite having a graphitization degree of 94% to 98% and an average particle size D50 of 6µm to 18µm as negative active material.
     
    2. The lithium ion secondary battery according to claim 1, wherein the graphitization degree of the negative active material is 94% to 96%.
     
    3. The lithium ion secondary battery according to claim 1, wherein the graphite is selected from natural graphite, artificial graphite, or a mixture thereof.
     
    4. The lithium ion secondary battery according to claim 1, wherein the cathode comprises a positive current collector and a positive material layer, and the positive material layer comprises a positive active material with formula LixNiaCobMcO2, M is at least one selected from the group consisting of Mn and Al, 0.95≤x≤ 1.2, 0 <a <1, 0 <b <1, 0 <c <1 and a + b + c = 1.
     
    5. The lithium ion secondary battery according to claim 4, wherein the positive active material is at least one selected from the group consisting of LiNi0.33Co0.33Mno.33O2, LiNi0.5Co0.2Mn0.3O2, LiNi0.5Co0.25Mn0.25O2, LiNi0.6Co0.2Mn0.2O2, LiNi0.8Co0.1Mn0.1O2, LiNi0.85Co0.1Mn0.05O2 and LiNi0.8Co0.15Al0.05O2.
     
    6. The lithium ion secondary battery according to any one of claims 4-5, wherein the positive active material has a dopant element selected from at least one of Al, Zr, Ti, B, Mg, V, Cr, and F.
     
    7. The lithium ion secondary battery according to any one of claims 4-6, wherein the positive active material has a coating layer and the coating layer contains at least one element selected from Al, Zr, Ti, and B.
     
    8. The lithium ion secondary battery according to any one of claims 1-3, wherein the negative active material has a coating layer and the coating layer comprises amorphous carbon.
     
    9. The lithium ion secondary battery according to claim 8, wherein the amorphous carbon is obtained by the carbonization of at least one material selected from the group consisting of polyvinyl butyral, bitumen, furfural resin, epoxy resin or phenolic resin.
     
    10. The lithium ion secondary battery according to claim 8, wherein the content of the amorphous carbon is 2% to 13%, preferably 5% to 10%, based on the total weight of the negative active material.
     
    11. The lithium ion secondary battery according to any one of claims 1-3, wherein the content of the negative active material is 92% to 98%, based on the total weight of the negative material layer.
     
    12. The lithium ion secondary battery according to any one of claims 4-7, wherein the content of the positive active material is 92% to 98%, based on the total weight of the positive material layer.
     


    Ansprüche

    1. Lithiumionen-Sekundärbatterie, umfassend eine Kathode, eine Anode, einen Separator und einen Elektrolyten, wobei die Anode einen negativen Stromabnehmer und eine negative Materialschicht umfasst, und die negative Materialschicht Graphit mit einem Graphitisierungsgrad von 94% bis 98% und einer durchschnittlichen Teilchengröße D50 von 6µm bis 18µm als negatives aktives Material aufweist.
     
    2. Lithiumionen-Sekundärbatterie nach Anspruch 1, wobei der Graphitisierungsgrad des negativen aktiven Materials 94% bis 96% beträgt.
     
    3. Lithiumionen-Sekundärbatterie nach Anspruch 1, wobei der Graphit aus natürlichem Graphit, künstlichem Graphit oder einer Mischung davon ausgewählt ist.
     
    4. Lithiumionen-Sekundärbatterie nach Anspruch 1, wobei die Kathode einen positiven Stromabnehmer und eine positive Materialschicht umfasst und die positive Materialschicht ein positives aktives Material mit der Formel LixNiaCobMcO2 umfasst, wobei M mindestens ein Element aus der aus Mn und Al bestehenden Gruppe ausgewählt ist, 0,95≤x≤ 1,2, 0<a<1, 0<b<1, 0<c<1 und a + b + c = 1.
     
    5. Lithiumionen-Sekundärbatterie nach Anspruch 4, wobei das positive aktive Material mindestens einen aus einer Gruppe ausgewählten Bestandteil enthält, die aus LiNi0,33Co0,33Mn0,33O2, LiNi0,5Co0,2Mn0,3O2, LiNi0,5Co0,25Mn0,25O2, LiNi0.6Co0.2Nn0.2O2, LiNi0.8Co0.1Mn0.1O2, LiNi0.85Co0.1Mn0.05O2 und LiNi0.8Co0.15Al0.05O2 besteht.
     
    6. Lithiumionen-Sekundärbatterie nach einem der Ansprüche 4 bis 5, wobei das positive aktive Material ein Dotierelement aufweist, das aus mindestens einem von Al, Zr, Ti, B, Mg, V, Cr und F ausgewählt ist.
     
    7. Lithiumionen-Sekundärbatterie nach einem der Ansprüche 4 bis 6, wobei das positive aktive Material eine Beschichtungsschicht aufweist und die Beschichtungsschicht mindestens ein aus Al, Zr, Ti und B ausgewähltes Element enthält.
     
    8. Lithiumionen-Sekundärbatterie nach einem der Ansprüche 1 bis 3, wobei das negative aktive Material eine Beschichtungsschicht aufweist und die Beschichtungsschicht amorphen Kohlenstoff umfasst.
     
    9. Lithiumionen-Sekundärbatterie nach Anspruch 8, wobei der amorphe Kohlenstoff durch Karbonisierung von mindestens einem Material erhalten wird, das aus der aus Polyvinylbutyral, Bitumen, Furfuralharz, Epoxidharz oder Phenolharz bestehenden Gruppe ausgewählt ist.
     
    10. Lithiumionen-Sekundärbatterie nach Anspruch 8, wobei der Gehalt an amorphem Kohlenstoff 2% bis 13%, vorzugsweise 5% bis 10%, bezogen auf das Gesamtgewicht des negativen aktiven Materials beträgt.
     
    11. Lithiumionen-Sekundärbatterie nach einem der Ansprüche 1 bis 3, wobei der Gehalt dem negativen aktiven Material 92% bis 98% beträgt, bezogen auf das Gesamtgewicht der negativen Materialschicht.
     
    12. Lithiumionen-Sekundärbatterie nach einem der Ansprüche 4 bis 7, wobei der Gehalt dem positiven aktiven Material 92% bis 98% beträgt, bezogen auf das Gesamtgewicht der positiven Materialschicht.
     


    Revendications

    1. Batterie rechargeable au lithium-ion comprenant une cathode, une anode, un séparateur et un électrolyte, dans laquelle l'anode comprend un collecteur de courant négatif et une couche de matériau négatif, et la couche de matériau négatif comprend du graphite ayant un degré de graphitisation de 94 % à 98 % et une taille de particule moyenne D50 de 6 µm à 18 µm en tant que matériau actif négatif.
     
    2. Batterie rechargeable au lithium-ion selon la revendication 1, dans laquelle le degré de graphitisation du matériau actif négatif est de 94 % à 96 %.
     
    3. Batterie rechargeable au lithium-ion selon la revendication 1, dans laquelle le graphite est choisi parmi le graphite naturel, le graphite artificiel, ou un mélange de ceux-ci.
     
    4. Batterie rechargeable au lithium-ion selon la revendication 1, dans laquelle la cathode comprend un collecteur de courant positif et une couche de matériau positif, et la couche de matériau positif comprend un matériau actif positif ayant la formule LixNiaCobMcO2, M est au moins l'un choisi dans le groupe constitué de Mn et Al, 0,95 ≤ x ≤ 1,2, 0 < a < 1,0 < b < 1,0 < c < 1 et a + b + c = 1.
     
    5. Batterie rechargeable au lithium-ion selon la revendication 4, dans laquelle le matériau actif positif est au moins l'un choisi dans le groupe constitué de LiNi0,33Co0,33Mn0,33O2, LiNi0,5Co0,2Mn0,3O2, LiNi0,5Co0,25Mn0,25O2, LiNi0,6Co0,2Mn0,2O2, LiNi0,8Co0,1Mn0,1O2, LiNi0,85Co0,1Mn0,05O2 et LiNi0,8Co0,15Al0,05O2.
     
    6. Batterie rechargeable au lithium-ion selon l'une quelconque des revendications 4 à 5, dans laquelle le matériau actif positif comporte un élément dopant choisi parmi au moins l'un de Al, Zr, Ti, B, Mg, V, Cr et F.
     
    7. Batterie rechargeable au lithium-ion selon l'une quelconque des revendications 4 à 6, dans laquelle le matériau actif positif comporte une couche de revêtement et la couche de revêtement contient au moins un élément choisi parmi Al, Zr, Ti et B.
     
    8. Batterie rechargeable au lithium-ion selon l'une quelconque des revendications 1 à 3, dans laquelle le matériau actif négatif comporte une couche de revêtement et la couche de revêtement comprend du carbone amorphe.
     
    9. Batterie rechargeable au lithium-ion selon la revendication 8, dans laquelle le carbone amorphe est obtenu par la carbonisation d'au moins un matériau choisi dans le groupe constitué des polyvinylbutyral, bitume, résine furfural, résine époxy ou résine phénolique.
     
    10. Batterie rechargeable au lithium-ion selon la revendication 8, dans laquelle la teneur du carbone amorphe est de 2 % à 13 %, de préférence 5 % à 10 %, sur la base du poids total du matériau actif négatif.
     
    11. Batterie rechargeable au lithium-ion selon l'une quelconque des revendications 1 à 3, dans laquelle la teneur du matériau actif négatif est de 92 % à 98 %, sur la base du poids total de la couche de matériau négatif.
     
    12. Batterie rechargeable au lithium-ion selon l'une quelconque des revendications 4 à 7, dans laquelle la teneur du matériau actif positif est de 92 % à 98 %, sur la base du poids total de la couche de matériau positif.
     






    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description




    Non-patent literature cited in the description