CN115566137B - High-energy-density pole piece, preparation method thereof and battery cell - Google Patents
High-energy-density pole piece, preparation method thereof and battery cell Download PDFInfo
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- CN115566137B CN115566137B CN202211399589.8A CN202211399589A CN115566137B CN 115566137 B CN115566137 B CN 115566137B CN 202211399589 A CN202211399589 A CN 202211399589A CN 115566137 B CN115566137 B CN 115566137B
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- 238000002360 preparation method Methods 0.000 title abstract description 20
- 239000011149 active material Substances 0.000 claims abstract description 74
- 229920001940 conductive polymer Polymers 0.000 claims abstract description 74
- 239000011230 binding agent Substances 0.000 claims abstract description 21
- 239000002002 slurry Substances 0.000 claims abstract description 19
- 229920000547 conjugated polymer Polymers 0.000 claims abstract description 10
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 27
- 229910052744 lithium Inorganic materials 0.000 claims description 27
- 238000000034 method Methods 0.000 claims description 20
- 239000011248 coating agent Substances 0.000 claims description 15
- 238000000576 coating method Methods 0.000 claims description 15
- 239000003292 glue Substances 0.000 claims description 15
- 238000005096 rolling process Methods 0.000 claims description 15
- 238000001035 drying Methods 0.000 claims description 12
- 239000002904 solvent Substances 0.000 claims description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- 229910002804 graphite Inorganic materials 0.000 claims description 9
- 239000010439 graphite Substances 0.000 claims description 9
- 239000000178 monomer Substances 0.000 claims description 8
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 7
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 claims description 6
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 6
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 claims description 6
- 239000002019 doping agent Substances 0.000 claims description 6
- 229920001197 polyacetylene Polymers 0.000 claims description 6
- 229920000767 polyaniline Polymers 0.000 claims description 6
- 239000007787 solid Substances 0.000 claims description 6
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 5
- 239000002033 PVDF binder Substances 0.000 claims description 5
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 5
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 5
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 claims description 4
- 239000002253 acid Substances 0.000 claims description 4
- COHDHYZHOPQOFD-UHFFFAOYSA-N arsenic pentoxide Chemical compound O=[As](=O)O[As](=O)=O COHDHYZHOPQOFD-UHFFFAOYSA-N 0.000 claims description 4
- 239000008367 deionised water Substances 0.000 claims description 4
- 229910021641 deionized water Inorganic materials 0.000 claims description 4
- 238000007756 gravure coating Methods 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- ZCYVEMRRCGMTRW-UHFFFAOYSA-N 7553-56-2 Chemical group [I] ZCYVEMRRCGMTRW-UHFFFAOYSA-N 0.000 claims description 3
- 239000011630 iodine Substances 0.000 claims description 3
- 229910052740 iodine Inorganic materials 0.000 claims description 3
- 230000033116 oxidation-reduction process Effects 0.000 claims description 3
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 claims description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 2
- UKOVZLWSUZKTRL-UHFFFAOYSA-N naphthalid Chemical compound C1=CC(C(=O)OC2)=C3C2=CC=CC3=C1 UKOVZLWSUZKTRL-UHFFFAOYSA-N 0.000 claims description 2
- 229920000128 polypyrrole Polymers 0.000 claims description 2
- 229920000123 polythiophene Polymers 0.000 claims description 2
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 claims description 2
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 claims description 2
- QLUMLEDLZDMGDW-UHFFFAOYSA-N sodium;1h-naphthalen-1-ide Chemical compound [Na+].[C-]1=CC=CC2=CC=CC=C21 QLUMLEDLZDMGDW-UHFFFAOYSA-N 0.000 claims description 2
- 239000011888 foil Substances 0.000 abstract description 14
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 33
- 229910001416 lithium ion Inorganic materials 0.000 description 33
- 239000003792 electrolyte Substances 0.000 description 13
- 239000006258 conductive agent Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 10
- 238000001556 precipitation Methods 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 8
- 238000007599 discharging Methods 0.000 description 8
- 239000012528 membrane Substances 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 7
- 239000011889 copper foil Substances 0.000 description 7
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 6
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000003756 stirring Methods 0.000 description 6
- 229910021383 artificial graphite Inorganic materials 0.000 description 5
- 238000007765 extrusion coating Methods 0.000 description 5
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical group O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 230000009471 action Effects 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 229910021385 hard carbon Inorganic materials 0.000 description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 3
- 238000011056 performance test Methods 0.000 description 3
- 239000007774 positive electrode material Substances 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 229910013870 LiPF 6 Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 2
- 230000005684 electric field Effects 0.000 description 2
- 238000011049 filling Methods 0.000 description 2
- 229910003002 lithium salt Inorganic materials 0.000 description 2
- 159000000002 lithium salts Chemical class 0.000 description 2
- 239000007773 negative electrode material Substances 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 229910000572 Lithium Nickel Cobalt Manganese Oxide (NCM) Inorganic materials 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000002174 Styrene-butadiene Substances 0.000 description 1
- FBDMTTNVIIVBKI-UHFFFAOYSA-N [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] Chemical compound [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] FBDMTTNVIIVBKI-UHFFFAOYSA-N 0.000 description 1
- OBNDGIHQAIXEAO-UHFFFAOYSA-N [O].[Si] Chemical compound [O].[Si] OBNDGIHQAIXEAO-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical group II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- SBWRUMICILYTAT-UHFFFAOYSA-K lithium;cobalt(2+);phosphate Chemical compound [Li+].[Co+2].[O-]P([O-])([O-])=O SBWRUMICILYTAT-UHFFFAOYSA-K 0.000 description 1
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000027756 respiratory electron transport chain Effects 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 239000007784 solid electrolyte Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000009469 supplementation Effects 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0404—Methods of deposition of the material by coating on electrode collectors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Materials Engineering (AREA)
- Secondary Cells (AREA)
Abstract
The invention belongs to the technical field of battery manufacturing, and particularly relates to a high-energy-density pole piece, a preparation method thereof and an electric core. The invention provides a high energy density pole piece, comprising: and the redox type conductive polymer layer and the high-energy type active material layer are sequentially arranged from one side surface or two side surfaces of the current collector outwards. The redox type conductive polymer layer adopts conjugated polymer with a conjugated structure, the conjugated polymer is mixed with a binder to prepare slurry, the slurry is coated on the foil layer, and when the foil layer is charged, electrons can be reduced to enter an active material through electron loss and electron loss, and the rate charge of a battery is not influenced, which is equivalent to temporarily storing electrons in a container and gradually releasing the electrons to the active material.
Description
Technical Field
The invention belongs to the technical field of battery manufacturing, and particularly relates to a high-energy-density pole piece, a preparation method thereof and an electric core.
Background
The rapid development of lithium ion batteries has led to various types of batteries, including fast-charge lithium ion batteries, high energy density lithium ion batteries, low cost lithium ion batteries, and ultra-long cycle lithium ion batteries. At present, along with the rapid development of electric vehicles, the requirements of the market on the electric vehicles are more and more strict, and the requirements of long endurance mileage are met and rapid charging is realized. However, the properties of the positive and negative electrode materials used for high energy density batteries, such as surface area and particle size, have determined that they cannot achieve charge and discharge at rates of 2C to 10C or higher, and are inherently low in conductivity. In the preparation process of the fast-charging battery, more conductive agent needs to be added, the active percentage of the main material is lower, and the energy density is far lower than that of the high-energy density battery. On the other hand, the overlarge current density of the high-energy-density battery in the charging and discharging processes can cause great potential safety hazard caused by lithium precipitation of the battery.
The lithium separation of the high energy density battery is a continuous process, and the basic reason can be understood that when a current of 2C reaches a copper foil, 2C electrons are generated, and then the lithium ions in the electrolyte of the battery need 2C amount to react with the active material to neutralize the 2C electrons, but the conductivity of the material can only bear the 1C neutralization reaction process, and more 1C lithium ions are deposited on the surface of the material. The main reason is that the copper foil has high conductivity, but the material has low conductivity, so that lithium ions are not only transmitted to the whole active space, and excessive lithium ions are accumulated in the area with high current density, and then the reaction is carried out to generate lithium precipitation. To solve the problem of lithium precipitation, the concentration of lithium ions in the battery is reduced and the rate of current transfer into the active material is limited while the battery is being charged.
Chinese patent CN 111354950a discloses a foil, a method for preparing the same, a battery cell, a battery module and an energy storage device, wherein a lithium salt doped conductive polymer is coated on a current collector, and the mutual conversion between conductivity and insulation is realized by doping and de-doping of lithium salt, so that an electronic channel between the foil and an active material can be cut off, and overcharge and overdischarge are prevented. However, this method does not realize high-rate charge and discharge with high energy density, and also solves the problem of lithium precipitation of the battery.
Therefore, finding a method that can improve the quick charge performance of a lithium ion battery without reducing the energy density of the battery is an urgent problem to be solved in the field of secondary batteries.
Disclosure of Invention
The invention provides a high-energy-density pole piece, a preparation method thereof and a battery core, and aims to solve the problems that in the prior art, a high-energy-density battery cannot realize high-rate charge and discharge and lithium is separated from the battery under a high-rate charge condition.
In view of the above technical drawbacks, one of the purposes of the present invention is to provide a high energy density type pole piece, another purpose of the present invention is to provide a method for manufacturing the high energy density type pole piece, and another purpose of the present invention is to provide an electrical core comprising the high energy density type pole piece.
In a first aspect, the present invention provides a high energy density pole piece comprising: and the redox type conductive polymer layer and the high-energy type active material layer are sequentially arranged from one side surface or two side surfaces of the current collector outwards.
In the above high energy density pole piece, as a preferred embodiment, the conductive polymer in the redox type conductive polymer layer is a doped conjugated polymer of polyacetylene, polypyrrole, polythiophene or polyaniline;
the dopant in the doped conjugated polymer is preferably iodine vapor, protonic acid, arsenic pentoxide, lithium naphthalide or sodium naphthalide;
the dopant comprises 5-50% (e.g., 15%, 25%, 35%, 45%) of the doped conjugated polymer, preferably 10-30%.
Preferably, the conductivity of the conductive polymer is 10 to 10 6 S/cm (e.g., 10) 2 S/cm、10 3 S/cm、10 4 S/cm、10 5 S/cm); but are not limited to, the recited values, and other non-recited values within the range of values are equally applicable.
In the above-mentioned high energy density pole piece, as a preferable real-time method, the thickness of the redox type conductive polymer layer is 1 to 100 μm (for example, 10 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm), preferably 5 to 20 μm;
and/or the high energy density pole piece has a thickness of 50-200 μm (e.g., 70 μm, 90 μm, 110 μm, 130 μm, 150 μm, 170 μm, 190 μm).
In the above-mentioned high energy density type pole piece, as a preferred embodiment, the active material of the high energy type active material layer is graphite type or/and carbon silicon type high energy type active material. High energy active materials having theoretical energy densities above 140mAh/g are preferred. The graphite high-energy active material is artificial graphite.
In the above-mentioned high energy density pole piece, as a preferred embodiment, the redox type conductive polymer layer is obtained by applying a dope containing a conductive polymer onto a current collector, drying, and rolling.
In one embodiment of the present invention, the high energy type active material layer is obtained by applying a slurry containing a high energy density type active material onto the redox type conductive polymer layer, drying, and rolling.
In one embodiment of the invention, the current collector has a thickness of 4.5-8 μm (e.g., 5 μm, 7 μm).
In one embodiment of the present invention, the redox type conductive polymer layer and the high energy type active material layer are prepared by rolling at a compaction ratio (i.e., thickness before rolling/thickness after rolling=1.2 to 1.8) of 1.2 to 1.8 (e.g., 1.3, 1.4, 1.6, 1.7).
In a second aspect, the invention also provides a preparation method of the high-energy-density pole piece, which comprises the following steps,
s1: coating the glue solution containing the conductive polymer on one side surface or two side surfaces of the current collector, and drying and rolling to obtain the current collector with the redox conductive polymer layer;
s2: and coating the slurry containing the active material of the high-energy active material layer on the redox conductive polymer layer, and drying and rolling to obtain the high-energy density pole piece.
In the above method for preparing a high energy density pole piece, as a preferred embodiment, in S1, the coating mode of the glue solution containing the conductive polymer is one of micro gravure coating, gravure coating and slit coating;
and/or the coating thickness of the electroconductive polymer paste is 1 μm to 100 μm (e.g., 10 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm), more preferably 5 μm to 20 μm;
and/or the solids content of the dope containing the conductive polymer is 55% -70% (e.g., 50%, 60%, 65%, 70%); the solid content here is the mass content;
and/or the glue solution containing the conductive polymer comprises an oxidation-reduction type conductive polymer, a first binder and a first solvent.
More preferably, the mass ratio of the redox-type conductive polymer to the first binder is (95-100): (0-5), and the sum of the proportion of the two is 100;
and/or the first solvent comprises deionized water, acetonitrile, methanol, and N-methylpyrrolidone;
and/or the first binder is one or more of sodium carboxymethylcellulose (SBR), styrene-butadiene rubber (CMC), polyvinylidene fluoride (PVDF), polyethylene oxide (PEO); binders used to prepare the conductive polymer paste include, but are not limited to, the above-described binders, and binders that can perform the same binding function can be suitably used in the present invention.
In the preparation method of the redox type conductive polymer layer, the addition amount of the first solvent is calculated according to the solid content of the conductive polymer glue solution, the mass of the redox type conductive polymer and the mass of the binder.
In the above-described method for manufacturing a high energy density type pole piece, as a preferred embodiment, the slurry of the active material containing the high energy type active material layer further includes a conductive agent, a second binder, and a second solvent. The types and the amount of the conductive agent, the second binder and the second solvent may be adjusted according to the types of the active materials, and are all conventional techniques, and will not be described herein.
In a third aspect, the invention further provides an electric core, which comprises a plurality of negative pole pieces, a plurality of diaphragms and a plurality of positive pole pieces, wherein the negative pole pieces and the positive pole pieces are alternately arranged, the diaphragms are arranged between each positive pole piece and each negative pole piece, the negative pole pieces comprise the high-energy-density type pole pieces and the quick-charging type pole pieces, and the active material multiplying power of the quick-charging type pole pieces is larger than that of the high-energy-density type pole pieces.
In the above battery cell, as a preferred embodiment, the number of the fast-charging type pole pieces satisfies the following formula:
n 0 =N(C 2 -C 1 )/(C 3 +C 2 -C 1 );
wherein n is 0 Is the number of the fast-charging pole pieces in the battery cell, N is the total number of the negative pole pieces in the battery cell, C 2 Is the actual multiplying power of the battery cell, C 1 Is the maximum bearing multiplying power of the high energy density type pole piece in the battery core, C 3 Is the maximum bearing multiplying power of the quick-charging pole piece.
In the present invention, n 0 When the decimal place exists in the result of the calculation, the integer is taken, the integer part or the integer part is directly taken, and 1 is added, without considering the numerical value after the decimal place.
According to the invention, by setting the number of the quick-charging type pole pieces in the battery core, the high-rate charging and discharging can be performed under the condition that the energy density of the battery core is not affected.
In the above battery cell, as a preferred embodiment, the fast-charging pole pieces are uniformly distributed in the battery cell.
In the above battery cell, as a preferred embodiment, the battery cell includes a plurality of units and a first positive electrode sheet disposed between adjacent units; each monomer comprises one quick-charging type pole piece, and a second positive pole piece and a high-energy density type pole piece which are arranged on two sides of the quick-charging type pole piece, wherein in the monomer, the number of the second positive pole pieces on one side of the quick-charging type pole piece is the same as that of the high-energy density type pole pieces, and the number of the pole pieces on two sides of the quick-charging type pole piece is the same as or similar to that of the high-energy density type pole pieces (for example, in the monomer, the difference between the total number of pole pieces on one side and the total number of pole pieces on the other side is 2 or 4, and when the difference is 2, namely, one side is less than one second positive pole piece and one high-energy density type pole piece; the second positive pole pieces and the negative pole pieces are alternately arranged, and second diaphragms are arranged between the adjacent second positive pole pieces and the adjacent negative pole pieces; a first diaphragm is also arranged between the adjacent monomer and the first positive pole piece.
In order to clearly show the preferred structure of the battery cell, in the preferred battery cell structure, the positive electrode plate is divided into a second positive electrode plate positioned in a single body and a first positive electrode plate positioned outside the single body according to different positions of the positive electrode plate, and the preparation methods and the active materials of the positive electrode plates at different positions are the same; dividing the diaphragm into a second diaphragm positioned in the single body and a first diaphragm positioned outside the single body according to different positions of the diaphragm, wherein the preparation methods and materials of the diaphragms at different positions are the same; the negative pole piece comprises a quick-charging pole piece and a high-energy density pole piece.
In the above battery cell, as a preferred embodiment, the ratio of the thickness of the active material layer of the fast-charging type pole piece to the thickness of the active material layer of the high-energy density pole piece is (1-1.5): 1, a step of;
the thickness of the high-energy density pole piece is 50-200 mu m.
In the above battery cell, as a preferred embodiment, the active material of the fast-charging type pole piece is graphite or/and carbon-silicon fast-charging type active material; the graphite-based rapid-charging active material is preferably hard carbon or/and soft carbon. The multiplying power of the active material of the quick-charging type pole piece is 1-50C, preferably 1-5C.
In the above battery cell, as a preferred embodiment, the difference between the active material magnification of the fast-charging type pole piece and the active material magnification of the high-energy density pole piece is 0.2C-2C, preferably 0.2C-1C; for example, the maximum charge-discharge multiplying power of the active material of the high-energy active material layer is 0.33C, and the multiplying power of the active material of the fast-charge pole piece is 0.83-1.33C. The difference of the two times is within the preferred range of the invention, so that the concentration difference can be better constructed, and the occurrence of lithium precipitation can be avoided. When the multiplying power difference is too large, lithium is separated from the quick-charging type pole piece, and when the multiplying power difference is too small, the concentration difference cannot be constructed, and the effect of the quick-charging type pole piece cannot be exerted without the concentration difference.
In certain embodiments of the present invention, the fast-charge electrode sheet is prepared according to conventional negative electrode sheet preparation processes, such as slurrying the active material, conductive agent, binder, and solvent of the fast-charge electrode sheet, and then coating it onto the current collector.
In certain embodiments of the present invention, the application of both the fast-charging pole piece active material and the high-energy active material layer active material may be accomplished using one of extrusion coating, transfer coating, or spray coating.
The battery cell can be coiled or laminated. The cell of the invention may also include conventional components such as electrolyte/solid electrolyte, housing, etc.
The active material of the positive electrode plate of the battery core can be a common positive electrode active material of a secondary battery, and the active material is preferably a lithium battery positive electrode active material, such as a ternary material of lithium iron phosphate, lithium cobalt phosphate, lithium manganese iron phosphate or lithium nickel cobalt manganese oxide. The preparation of the positive electrode plate can be prepared by adopting a conventional wet method or a conventional dry method.
In the battery cell of the invention, the high-energy-density pole piece and the quick-charging pole piece are used as the negative electrode, and the current collector is preferably copper foil.
Compared with the prior art, the invention has at least one of the following beneficial effects:
1. the redox type conductive polymer layer adopts conjugated polymer with a conjugated structure, the conjugated polymer is mixed with a binder to prepare slurry, the slurry is coated on the foil layer, and when the foil layer is charged, electrons can be reduced to enter an active material through electron loss and electron loss, and the rate charge of a battery is not influenced, which is equivalent to temporarily storing electrons in a container and gradually releasing the electrons to the active material.
2. The redox conductive polymer provided by the invention can combine electrons at low potential, gradually release electrons along with the gradual rise of potential, and effectively solve the chemical reaction of the high-energy-density active material, so that the rate performance, namely the quick charge performance, of the redox conductive polymer is improved.
3. The invention provides a battery cell, wherein a quick-charging type pole piece is inserted into the battery cell, so that the battery cell can be quickly combined with lithium ions, a lithium ion concentration gradient is constructed between the quick-charging type pole piece and a high-energy density type pole piece, the lithium ion concentration on the surface of the high-energy density type pole piece is reduced, the possibility of lithium precipitation of the high-energy density type pole piece is effectively reduced, and the quick-charging performance of a battery is improved.
4. According to the invention, the battery core structure is optimized, the quick-charging type active material pole piece is added, the quick-charging type pole piece and the high-energy-density type pole piece are manufactured into one battery core, the quick-charging type pole piece can be quickly combined with lithium ions during high-power charging, so that lithium in electrolyte is consumed, and the movement speed of the lithium ions to the high-energy-density type pole piece can be slowed down under the action of concentration difference.
Drawings
FIG. 1 is a schematic diagram of a high energy density pole piece made in accordance with the present invention;
fig. 2 is a schematic structural diagram of the battery cell prepared in example 1;
fig. 3 is a schematic diagram of the overall structure of the battery cell prepared in example 1;
FIG. 4 is a schematic diagram of the operation of the redox-type conductive polymer according to example 1;
fig. 5 is a schematic diagram of the working principle of the negative electrode plate, wherein (a) is a schematic diagram of the working principle of the fast-charging electrode plate and the high-energy-density electrode plate in the charging and discharging process; (b) Is a schematic diagram of the working principle of the high energy density type pole piece in the charging and discharging process;
FIG. 6 is a disassembled view of the battery cell after 100 cycles of the battery cell of example 1;
fig. 7 is a schematic structural diagram of one of the battery cells prepared in example 2;
fig. 8 is a cell disassembly after 100 cycles of the cell of comparative example 1.
The reference numerals are as follows:
1-a high energy density type pole piece; 2-quick-filling pole pieces; 3-a positive pole piece; 4-a high energy type active material layer; a 5-redox type conductive polymer layer; 6-foil layer (current collector); 7-quick-fill active material layer.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The examples of the present invention are implemented on the premise of the technical scheme of the present invention, and detailed implementation modes and processes are given, but the protection scope of the present invention is not limited to the following examples, in which the process parameters of specific conditions are not noted, and generally according to conventional conditions.
The endpoints of the ranges and any values disclosed in the present invention are not limited to the precise range or value, and the range or value should be understood to include values close to the range or value. For numerical ranges, one or more new numerical ranges may be obtained in combination with each other between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point values, and are to be considered as specifically disclosed in the present invention.
Example 1
The present embodiment provides a method of preparing a redox type conductive polymer layer on a current collector, comprising the steps of:
(1) Selected conductivity of 10 4 S/cm of a redox type polyacetylene (the dopant is iodine, and the molar ratio of iodine to the polyacetylene is 10%) was used as the redox type conductive polymer. The mass ratio of polyacetylene to styrene-butadiene rubber (CMC) is 96:4. firstly, calculating the content of deionized water according to the solid content of the conductive polymer glue solution by 65%, then adding the styrene-butadiene rubber and the deionized water into a stirring tank, wherein the stirring speed is 3000rpm for 120min, adding the polyacetylene, and stirring for 90min at 3500rpm to obtain the conductive polymer glue solution.
(2) The conductive polymer glue solution was coated on both sides of a copper foil (thickness: 6 μm) using a micro gravure coater, and dried and rolled to obtain a current collector with a redox type conductive polymer layer having a thickness of 20 μm, i.e., a composite current collector having a thickness of 26 μm.
The embodiment also provides a high-energy-density pole piece and a preparation method thereof, wherein the preparation method comprises the following steps:
artificial graphite is selected as an active material of the high-energy-density pole piece, and the charge-discharge multiplying power is 0.5 ℃. Artificial graphite and binder CMC, conductive agent SP according to 96.5:2:1.5, coating the slurry on the redox type conductive polymer layer in an extrusion coating mode, drying and rolling to obtain the high-energy-density pole piece, wherein the thickness of the single-sided high-energy type active material layer is 58 mu m (namely, the total thickness of the two-sided high-energy type active material layers is 116 mu m). The specific structure of the high-energy density type pole piece is shown in fig. 1, and the pole piece comprises a foil layer 6, redox type conductive polymer layers 5 arranged on two sides of the foil layer 6, and a high-energy type active material layer 4 arranged on the surface of the redox type conductive polymer layers 5. The thickness of the high energy density pole piece was 142 μm.
The embodiment also provides a preparation method of the quick-charging pole piece, which comprises the following steps:
hard carbon is selected as an active material of the fast-charge pole piece, and the charge-discharge multiplying power is 2C. Hard carbon and binder CMC, conductive agent SP according to 95.5:2.5:2 are prepared into slurry together by a proportion, the slurry is coated on two sides of a copper foil (the thickness is 6 mu m) by adopting an extrusion coating mode, and the quick-charging type pole piece is obtained after drying and rolling, wherein the thickness of an active material layer is 58 mu m. The thickness of the quick-charging type pole piece is 122 mu m.
The preparation method of the positive plate comprises the following steps: lithium iron phosphate and conductive agent SP, binder PVDF according to 96.8:2:1.2, coating the prepared slurry on two sides of an aluminum foil, drying and rolling to obtain the positive plate.
The embodiment also provides a battery cell, which basically comprises a positive plate, a negative plate and a diaphragm. The negative electrode sheet comprises two types of high-energy-density type electrode sheets and quick-charging type electrode sheets prepared in the embodiment, and the following formula is adopted: n is n 0 =N(C 2 -C 1 )/(C 3 +C 2 -C 1 ) The total number of layers of the battery cell negative electrode sheet is 20, and the actual multiplying power C of the battery cell 2 1C, maximum bearing multiplying power C of high energy density pole piece 1 Maximum bearing multiplying power C of quick-charge pole piece of 0.5C 3 2C. The number of the quick-charging type pole pieces is 4 pieces according to the formula. The schematic diagrams of the cell are shown in fig. 2 and 3, wherein fig. 2 shows the structure of a single body in the cell, namely, two sides of one fast-charging type pole piece 2 are respectively provided with 2 high-energy- density pole pieces 1 and 2 positive pole pieces 3, the positive pole pieces 3 and the negative pole pieces 3 are alternately arranged, and the adjacent pole pieces are arranged at intervalsA membrane (not shown in the figure), specifically, two sides of the fast-charging type pole piece 2 are overlapped with membranes, then the positive pole piece 3 is overlapped on the membranes, then the membrane is overlapped on the positive pole piece 3, then the high-energy-density type pole piece 1 is overlapped on the membrane, then the membranes, the positive pole piece 3, the membranes and the high-energy-density type pole piece 1 are sequentially overlapped, the structure is a unit constituting a battery cell, the whole battery cell comprises four units according to the unit lamination, the positive pole piece 3 is arranged between the units, and the two sides of the positive pole piece 3 between the units are overlapped with the membranes, thereby forming the basic structure of the whole battery cell, see fig. 3. Of course, the cell also includes necessary electrolyte and casing, which may be conventional electrolyte and casing of lithium ion battery, and the electrolyte of the electrolyte used in this embodiment is LiPF 6 The solvent is Ethylene Carbonate (EC) and dimethyl carbonate (DMC) with the volume ratio of 1:1, and the diaphragm is PE. The theoretical capacity of the resulting cell was 20Ah.
As shown in fig. 4, the redox type conductive polymer in the cell works in principle, the external circuit electrons first flow through the foil, the conductivity of the foil (10 6 S/cm) is high and almost does not constitute a hindrance to electrons, electrons are conducted to the conductive polymer, and the conductive polymer has excellent conductivity, although the conductivity is inferior to that of a foil, and since the conductive polymer is a redox type polymer having a conjugated structure, electrons can be lost by redox, and thus the electron transfer rate is relatively reduced but the number is not reduced. In the initial stage of charging, the voltage of the battery core is reduced by n-type doping compared with the conductive polymer with lower voltage, part of electrons are firstly contained in the conductive polymer, part of electrons are transmitted to the high-energy active material layer 4, the number of electrons received by the active material is reduced, the corresponding number of lithium ions is reduced, and the high-energy density type pole piece 1 is enough to process the lithium ions according to the multiplying power per se without precipitating lithium. As the voltage increases, the conductive polymer undergoes p-type doping and is oxidized to lose electron supplementation to the high-energy type active material layer 4. The redox type conductive polymer layer 5 corresponds to an electron storage device, temporarily stores electrons of a system, but does not reduce the number of electrons of the system or reduce the rate performance of the battery cell.
As shown in fig. 5, lithium ions are transferred between the fast charge type pole piece 2 and the high energy density type pole piece 1, and this transfer does not overlap the role of the redox type conductive polymer layer. During charging, the positive electrode loses lithium ions into the electrolyte, and then the lithium ions move from the positive electrode to the negative electrode and react with the negative electrode. Under the condition of high multiplying power, if the multiplying power of the negative electrode is lower than the charging multiplying power, the consumption of lithium ions in the electrolyte is in an unbalanced state, the concentration of the lithium ions can be rapidly increased, and the lithium ions can be rapidly deposited on the surface of the negative electrode material under the action of an electric field, so that lithium precipitation occurs. The lithium ions around the pole piece can be rapidly consumed in the charging process due to the fact that the quick-charging type negative pole piece has a larger charging multiplying power, the lithium ion concentration of the battery core without the quick-charging type negative pole piece is relatively uniform, and the battery core with the quick-charging type negative pole piece is seen from fig. 5 (b), and the lithium ions around the high-energy-density type pole piece can gradually move towards the negative pole of the quick-charging type pole piece under the action of concentration difference force and the electric field driving because of the reduction of the lithium ion concentration around the quick-charging type pole piece, so that the lithium ion concentration around the high-energy type negative pole piece is reduced, and the lithium precipitation risk is reduced.
The performance of the battery cell assembled by the embodiment is tested, and the specific testing method is as follows: scheme one: and under the condition of normal temperature of 25 ℃, the charging step is carried out to 3.65V at a multiplying power of 1C at constant current and constant voltage, the discharging step is carried out to 2.5V at a constant current of 0.5C, and after 100 cycles, the battery cell is disassembled to check whether lithium is separated from the surface of the pole piece. Simultaneously, a second scheme is set: the charging step is to charge to 3.65V with constant current and constant voltage at a multiplying power of 0.5C, the discharging step is to discharge to 2.5V with constant current of 0.5C, and after 100 cycles, the battery cell is disassembled to check whether the lithium is separated from the surface of the pole piece.
Under the action of the conductive polymer layer and the fast-charging negative electrode plate, the rate performance of the battery is obviously improved, the improvement from 0.5C to 1C can be completely realized, and as shown in fig. 6, after 100 circles of circulation, the battery core is disassembled to find that lithium precipitation does not occur on the surface of the electrode plate, and the specific result is shown in table 1.
Example 2
The present embodiment provides a method of preparing a redox type conductive polymer layer on a current collector, comprising the steps of:
(1) Selected conductivity of 10 3 S/cm of redox polyaniline (dopant is protonic acid, protonic acid accounts for 15% of the molar ratio of polyaniline). The mass ratio of polyaniline to polyethylene oxide (PEO) is 95:5.
firstly, calculating the content of N-methyl pyrrolidone (NMP) according to 70% of the solid content of the conductive polymer glue solution, then adding polyethylene oxide and N-methyl pyrrolidone into a stirring tank, stirring at 3500rpm for 100min, adding polyaniline, stirring at 4000rpm for 110min, and obtaining the conductive polymer glue solution.
(2) The conductive polymer glue solution was coated on both sides of a copper foil (thickness: 6 μm) using a micro gravure coater, and dried and rolled to obtain a current collector with a redox type conductive polymer layer having a thickness of 25 μm, i.e., a composite current collector having a thickness of 31 μm.
The embodiment also provides a high-energy-density pole piece and a preparation method thereof, wherein the preparation method comprises the following steps:
artificial graphite is selected as an active material of the high-energy-density pole piece, and the charge-discharge multiplying power is 1C. Artificial graphite, a binder CMC and a conductive agent SP according to 96:2:2, preparing the slurry together into slurry, coating the slurry on the redox type conductive polymer layer in an extrusion coating mode, and drying and rolling the slurry to obtain the high-energy-density pole piece, wherein the thickness of the single-sided high-energy-type active material layer is 50 mu m. The thickness of the high energy density pole piece is 131 μm. The specific structure of the high energy density pole piece is shown in figure 1.
The embodiment also provides a preparation method of the quick-charging pole piece, which comprises the following steps:
and (3) selecting the silicon-oxygen graphite as an active material of the quick-charge type pole piece, wherein the charge-discharge multiplying power is 3 ℃. Silica graphite (compounded by 30% of silica and 70% of graphite) and a binder CMC and a conductive agent SP according to the following ratio of 95:3:2 are prepared into slurry together by a proportion, the slurry is coated on two sides of a copper foil (the thickness is 6 mu m) by adopting an extrusion coating mode, and the quick-charging type pole piece is obtained after drying and rolling, wherein the thickness of a single-sided active material layer is 55 mu m. The thickness of the quick-filling type pole piece is 116 mu m.
The preparation method of the positive plate comprises the following steps: lithium iron phosphate and conductive agent SP, binder PVDF according to 96.8:2:1.2, coating the prepared slurry on two sides of an aluminum foil, drying and rolling to obtain the positive plate.
The embodiment also provides a battery cell, which basically comprises a positive plate, a negative plate and a diaphragm, wherein the negative plate comprises two types of high-energy-density pole pieces and quick-charging pole pieces prepared in the embodiment. According to the formula: n is n 0 =N(C 2 -C 1 )/(C 3 +C 2 -C 1 ) The total number of layers of the battery cell negative electrode sheet is 30, and the actual multiplying power C of the battery cell 2 2C, maximum bearing multiplying power C of high energy density pole piece 1 1C, maximum bearing multiplying power C of quick-charging pole piece 3 3C. And calculating the number of the quick-charging type pole pieces to 7 pieces according to a formula. As shown in the schematic diagram of the cell unit structure shown in FIG. 7, the two sides of the fast-charging type pole piece 2 are respectively provided with 3 high-energy-density type pole pieces 1 and 3 positive pole pieces 3, and as the number of the high-energy-density type pole pieces is 23, the two sides of each fast-charging type pole piece 2 cannot be guaranteed to be respectively provided with 3 high-energy-density type pole pieces, so that the single side of one fast-charging type pole piece 2 cannot be provided with 3 high-energy-density type pole pieces, 2 high-energy-density type pole pieces 1 and 2 positive pole pieces 3 can be changed, namely, three cell units are respectively provided with 3 high-energy-density type pole pieces 1 and 3 positive pole pieces 3 on the two sides of the fast-charging type pole piece 2, one cell unit is provided with 3 high-energy-density type pole pieces 1 and 3 positive pole pieces 3 on one side of the fast-charging type pole piece 2, and 2 positive pole pieces 3 on the other side. The entire cell is laminated according to the unit. Specifically, the whole battery cell comprises four units, the positive electrode plates 3 are arranged among the units, and the diaphragms are overlapped on two sides of the positive electrode plates 3 among the units, so that the basic structure of the whole battery cell is formed. Of course, the cell also includes necessary electrolyte and casing, which may be conventional electrolyte and casing of lithium ion battery, and the electrolyte of the electrolyte used in this embodiment is LiPF 6 The solvent is Ethylene Carbonate (EC) and dimethyl carbonate (DMC) with the volume ratio of 1:1, and the diaphragm is made of PP. Obtained byThe theoretical capacity of the cell is 35Ah.
The performance of the battery cell assembled by the embodiment is tested, and the specific testing method is as follows: scheme one: and under the condition of normal temperature of 25 ℃, the charging step is carried out to 3.65V at a multiplying power constant current and constant voltage of 2C, the discharging step is carried out to 2.5V at a constant current of 0.5C, and after 100 cycles, the battery cell is disassembled to check whether lithium is separated from the surface of the pole piece. Simultaneously, a second scheme is set: the charging step is to charge to 3.65V with constant current and constant voltage at a multiplying power of 1C, the discharging step is to discharge to 2.5V with constant current of 0.5C, and after 100 cycles, the battery cell is disassembled to check whether the lithium is separated from the surface of the pole piece.
In this embodiment, the conductive polymer with small conductivity is used because PEO is a conductive adhesive, which can play a role of conducting electrons, and the conductive polymer layer is coated and thickened, and the quick-charging pole piece with larger multiplying power is used, so that the actual multiplying power of the battery core can be effectively improved, and lithium is not separated, and the specific result is shown in table 1.
Comparative example 1
This comparative example is the same as example 1 except that there is no redox type conductive polymer layer and no fast charge type negative electrode tab. In the cell structure, the fast-charging type negative electrode plate is replaced by a high-energy-density electrode plate.
Cell performance test was the same as in example 1.
As shown in fig. 8, after 100 cycles, the battery cell was disassembled to find that lithium precipitation occurs on the surface of the pole piece, and the specific results are shown in table 1.
Comparative example 2
This comparative example is the same as example 1 except that there is no fast-charge type electrode sheet, and in the cell structure, the fast-charge type negative electrode sheet is replaced with a high-energy density type electrode sheet.
Cell performance test was the same as in example 1.
After 100 cycles, the battery is disassembled, and the lithium is separated from the surface of the pole piece in a small area, mainly because the concentration of lithium ions on the surface of the pole piece with high energy density is too high, the risk of lithium separation is increased, and the specific result is shown in Table 1.
Comparative example 3
This comparative example is the same as example 1, except that there is no redox type conductive polymer layer.
Cell performance test was the same as in example 1.
The battery was disassembled after 100 cycles to find that lithium was separated from the surface of the pole piece, but the lithium separation degree was lower than that of comparative example 1, and the specific results are shown in table 1.
Table 1 summary of battery disassembly results for different test magnifications
From the test summary results in table 1, it is known that the combination of the conductive polymer layer and the fast-charging type pole piece can buffer the concentration of the lithium ion battery on the surface of the high-energy type pole piece during high-rate charging, and can play a role in improving the battery rate.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Claims (9)
1. The battery cell is characterized by comprising a plurality of negative pole pieces, a plurality of diaphragms and a plurality of positive pole pieces, wherein the negative pole pieces and the positive pole pieces are alternately arranged, and the diaphragms are arranged between each positive pole piece and each negative pole piece;
the negative pole piece comprises a high-energy-density pole piece and a quick-charging pole piece, and the active material multiplying power of the quick-charging pole piece is larger than that of the high-energy-density pole piece;
the battery cell comprises a plurality of monomers and a first positive pole piece arranged between adjacent monomers; each monomer comprises one quick-charging type pole piece, and a second positive pole piece and the high-energy density type pole piece which are arranged on two sides of the quick-charging type pole piece;
the high energy density pole piece comprises: a current collector, and an oxidation-reduction type conductive polymer layer and a high-energy type active material layer which are sequentially arranged from one side surface or two side surfaces of the current collector, wherein the oxygenThe conductivity of the conductive polymer in the reduced conductive polymer layer is 10-10 6 S/cm。
2. The cell of claim 1, wherein the conductive polymer in the redox-type conductive polymer layer is a doped conjugated polymer of polyacetylene, polypyrrole, polythiophene, or polyaniline;
and/or the thickness of the redox type conductive polymer layer is 1-100 mu m;
and/or the active material of the high-energy active material layer is graphite or/and carbon-silicon high-energy active material.
3. The cell of claim 2, wherein the cell comprises a plurality of conductive traces,
the doping agent in the doped conjugated polymer is iodine vapor, protonic acid, arsenic pentoxide, lithium naphthalide or sodium naphthalide; the dopant accounts for 5-50% of the doped conjugated polymer;
and/or the thickness of the high-energy-density pole piece is 50-200 mu m;
and/or the theoretical energy density of the active material of the high-energy active material layer reaches more than 140 mAh/g.
4. The cell of claim 1, wherein the method for preparing the high energy density pole piece comprises the steps of:
s1: coating the glue solution containing the conductive polymer on one side surface or two side surfaces of the current collector, and drying and rolling to obtain the current collector with the redox conductive polymer layer;
s2: and coating the slurry containing the active material of the high-energy active material layer on the redox conductive polymer layer, and drying and rolling to obtain the high-energy density pole piece.
5. The cell of claim 4, wherein in S1, the glue solution containing the conductive polymer is applied by one of micro gravure coating, gravure coating and slot coating;
and/or the coating thickness of the conductive polymer glue solution is 1 mu m-100 mu m;
and/or the solid content of the glue solution containing the conductive polymer is 55% -70%;
and/or the glue solution containing the conductive polymer comprises an oxidation-reduction type conductive polymer, a first binder and a first solvent; the mass ratio of the redox type conductive polymer to the first binder is (95-100): (0-5), and the sum of the ratio of the two is 100.
6. The cell of claim 5, wherein the first solvent comprises deionized water, acetonitrile, methanol, and N-methylpyrrolidone;
and/or the first binder is one or more of sodium carboxymethyl cellulose, styrene-butadiene rubber, polyvinylidene fluoride and polyethylene oxide.
7. The cell of claim 1, wherein the number of fast-charge pole pieces satisfies the following formula:
n 0 =N(C 2 -C 1 )/(C 3 +C 2 -C 1 );
wherein n is 0 Is the number of the fast-charging pole pieces in the battery cell, N is the total number of the negative pole pieces in the battery cell, C 2 Is the actual multiplying power of the battery cell, C 1 Is the maximum bearing multiplying power of the high energy density type pole piece in the battery core, C 3 Is the maximum bearing multiplying power of the quick-charging pole piece;
and/or, the quick-charging type pole pieces are uniformly distributed in the battery cell;
and/or the difference between the active material multiplying power of the quick-charging type pole piece and the active material multiplying power of the high-energy density type pole piece is 0.2-2C.
8. The cell of claim 1, wherein in the single body, the number of the second positive pole piece at one side of the fast-charging pole piece is the same as the number of the high-energy-density pole pieces, and the number of the pole pieces at two sides of the fast-charging pole piece is the same or similar; the second positive pole pieces and the negative pole pieces are alternately arranged, and second diaphragms are arranged between the adjacent second positive pole pieces and the adjacent negative pole pieces; a first diaphragm is also arranged between the adjacent monomer and the first positive pole piece.
9. The cell of claim 1, wherein the cell comprises a plurality of conductive traces,
the active material of the quick-charging type pole piece is graphite or/and carbon silicon quick-charging type active material; the multiplying power of the active material of the quick-charging type pole piece is 1-50 ℃;
and/or the difference between the active material multiplying power of the quick-charging type pole piece and the active material multiplying power of the high-energy density type pole piece is 0.2-1C.
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