CN111786040A - Pole piece, application thereof and low-temperature-rise long-life lithium ion battery containing pole piece - Google Patents
Pole piece, application thereof and low-temperature-rise long-life lithium ion battery containing pole piece Download PDFInfo
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- CN111786040A CN111786040A CN202010802361.3A CN202010802361A CN111786040A CN 111786040 A CN111786040 A CN 111786040A CN 202010802361 A CN202010802361 A CN 202010802361A CN 111786040 A CN111786040 A CN 111786040A
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- pole piece
- coating
- conductive
- current collector
- conductive film
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 25
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 25
- 238000000576 coating method Methods 0.000 claims abstract description 124
- 239000011248 coating agent Substances 0.000 claims abstract description 116
- 239000006258 conductive agent Substances 0.000 claims description 71
- 239000011230 binding agent Substances 0.000 claims description 45
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 29
- 239000002041 carbon nanotube Substances 0.000 claims description 24
- 238000004519 manufacturing process Methods 0.000 claims description 21
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 19
- 229910021389 graphene Inorganic materials 0.000 claims description 19
- 239000000203 mixture Substances 0.000 claims description 15
- 235000010948 carboxy methyl cellulose Nutrition 0.000 claims description 14
- -1 polyphenylene ethylene Polymers 0.000 claims description 14
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 11
- 239000007773 negative electrode material Substances 0.000 claims description 10
- 239000007774 positive electrode material Substances 0.000 claims description 10
- 239000004642 Polyimide Substances 0.000 claims description 9
- 239000002253 acid Substances 0.000 claims description 9
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 9
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 9
- 229920001721 polyimide Polymers 0.000 claims description 9
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical group [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical group [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 8
- 229910052782 aluminium Inorganic materials 0.000 claims description 8
- 239000011889 copper foil Substances 0.000 claims description 8
- 239000011888 foil Substances 0.000 claims description 8
- 239000000126 substance Substances 0.000 claims description 8
- 229920002134 Carboxymethyl cellulose Polymers 0.000 claims description 6
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 6
- 239000013543 active substance Substances 0.000 claims description 6
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 6
- 239000008112 carboxymethyl-cellulose Substances 0.000 claims description 6
- 229910052744 lithium Inorganic materials 0.000 claims description 6
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 6
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 6
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 claims description 3
- 239000004917 carbon fiber Substances 0.000 claims description 3
- 238000005229 chemical vapour deposition Methods 0.000 claims description 3
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 claims description 3
- 238000007765 extrusion coating Methods 0.000 claims description 3
- 229910002804 graphite Inorganic materials 0.000 claims description 3
- 239000010439 graphite Substances 0.000 claims description 3
- 239000007770 graphite material Substances 0.000 claims description 3
- 238000007646 gravure printing Methods 0.000 claims description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims description 3
- ILXAVRFGLBYNEJ-UHFFFAOYSA-K lithium;manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[O-]P([O-])([O-])=O ILXAVRFGLBYNEJ-UHFFFAOYSA-K 0.000 claims description 3
- 238000001755 magnetron sputter deposition Methods 0.000 claims description 3
- 229920001197 polyacetylene Polymers 0.000 claims description 3
- 229920000767 polyaniline Polymers 0.000 claims description 3
- 229920000128 polypyrrole Polymers 0.000 claims description 3
- 229920000123 polythiophene Polymers 0.000 claims description 3
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 3
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 3
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 3
- 238000007650 screen-printing Methods 0.000 claims description 3
- 239000002210 silicon-based material Substances 0.000 claims description 3
- 229910000572 Lithium Nickel Cobalt Manganese Oxide (NCM) Inorganic materials 0.000 claims description 2
- 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 claims description 2
- 239000007888 film coating Substances 0.000 claims description 2
- 238000009501 film coating Methods 0.000 claims description 2
- 238000007740 vapor deposition Methods 0.000 claims description 2
- 239000012528 membrane Substances 0.000 claims 2
- 239000010410 layer Substances 0.000 abstract description 12
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- 239000002131 composite material Substances 0.000 description 43
- 239000011267 electrode slurry Substances 0.000 description 24
- 238000002156 mixing Methods 0.000 description 19
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 16
- 239000007787 solid Substances 0.000 description 16
- 238000003756 stirring Methods 0.000 description 16
- 230000000052 comparative effect Effects 0.000 description 15
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- 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 description 13
- 229920003123 carboxymethyl cellulose sodium Polymers 0.000 description 13
- 229940063834 carboxymethylcellulose sodium Drugs 0.000 description 13
- 239000002002 slurry Substances 0.000 description 11
- 239000003792 electrolyte Substances 0.000 description 10
- 238000007639 printing Methods 0.000 description 10
- 238000012360 testing method Methods 0.000 description 9
- 239000002033 PVDF binder Substances 0.000 description 8
- 210000004027 cell Anatomy 0.000 description 8
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 238000000034 method Methods 0.000 description 7
- FSSPGSAQUIYDCN-UHFFFAOYSA-N 1,3-Propane sultone Chemical compound O=S1(=O)CCCO1 FSSPGSAQUIYDCN-UHFFFAOYSA-N 0.000 description 6
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 description 6
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 description 6
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical group O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 6
- 230000001070 adhesive effect Effects 0.000 description 6
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 6
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 238000005096 rolling process Methods 0.000 description 6
- 229910001290 LiPF6 Inorganic materials 0.000 description 5
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- 239000011149 active material Substances 0.000 description 4
- 229940105329 carboxymethylcellulose Drugs 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 239000006256 anode slurry Substances 0.000 description 3
- 238000007599 discharging Methods 0.000 description 3
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- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000003331 infrared imaging Methods 0.000 description 2
- WGYKZJWCGVVSQN-UHFFFAOYSA-N propylamine Chemical compound CCCN WGYKZJWCGVVSQN-UHFFFAOYSA-N 0.000 description 2
- HFCVPDYCRZVZDF-UHFFFAOYSA-N [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O Chemical compound [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O HFCVPDYCRZVZDF-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
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Images
Classifications
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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
- 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
- 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
- H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
- H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/61—Types of temperature control
- H01M10/613—Cooling or keeping cold
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/61—Types of temperature control
- H01M10/617—Types of temperature control for achieving uniformity or desired distribution of temperature
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- 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
- H01M10/60—Heating or cooling; Temperature control
- H01M10/62—Heating or cooling; Temperature control specially adapted for specific applications
- H01M10/625—Vehicles
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/65—Means for temperature control structurally associated with the cells
- H01M10/653—Means for temperature control structurally associated with the cells characterised by electrically insulating or thermally conductive materials
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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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/60—Heating or cooling; Temperature control
- H01M10/65—Means for temperature control structurally associated with the cells
- H01M10/654—Means for temperature control structurally associated with the cells located inside the innermost case of the cells, e.g. mandrels, electrodes or electrolytes
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- H01—ELECTRIC ELEMENTS
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- H01M4/00—Electrodes
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- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
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- 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
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
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- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
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- H—ELECTRICITY
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2220/00—Batteries for particular applications
- H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
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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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- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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- Chemical & Material Sciences (AREA)
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- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The invention provides a pole piece, application thereof and a low-temperature-rise long-life lithium ion battery containing the pole piece, wherein the pole piece comprises a current collector, and at least two layers of active coatings and at least one layer of efficient conducting film are fixedly arranged on two opposite surfaces of the current collector; the active coating and the high-efficiency conductive film are arranged at intervals from the surface of the current collector from inside to outside, and the outermost layer is the active coating. The pole piece provided by the invention has the advantages that the existence of the high-efficiency conductive film can enable the current density distribution in the vicinity of the conductive film in the coating layer to be more uniform, and the uneven polarization and uneven heating are reduced.
Description
Technical Field
The invention belongs to the field of lithium ion batteries, and particularly relates to a pole piece, application thereof and a low-temperature-rise long-life lithium ion battery containing the pole piece.
Background
With the continuous progress of science and technology, lithium ion batteries are gradually applied to many fields, from portable electronic products to electric vehicles, energy storage power supplies, aviation fields and the like. In particular, in the case of an electric vehicle, in order to shorten the gap between the electric vehicle and the conventional vehicle, it is necessary to extend the single driving range and the service life as long as possible. The lithium ion battery releases heat in the charging and discharging processes, macroscopically shows the temperature rise of the battery, if the charging and discharging temperature rise of the battery is too high, the aging of an internal chemical system of the battery can be accelerated, and therefore the service life of the battery is shortened. At present, the design of reducing self-heating temperature rise of the lithium ion battery is usually considered to reduce the surface density of a pole piece, increase the proportion of a conductive agent in a formula, increase the thickness of a current collector and the like.
However, reducing the area density of the electrode plate with the same capacity requirement will increase the consumption of auxiliary materials (such as current collectors and separators), which not only reduces the energy density of the battery, but also increases the cost; increasing the proportion of conductive agent (inactive substance) in the formula will reduce the energy density of the battery on one hand, and increase the dispersion difficulty of homogenate on the other hand, which will affect the consistency of the battery; increasing the thickness of the current collector also decreases the energy density of the battery.
Disclosure of Invention
In view of the above, the present invention is directed to a pole piece, so as to overcome the defects of the prior art, and the existence of a high-efficiency conductive film can make the current density distribution in the vicinity of the conductive film inside the coating more uniform, thereby reducing non-uniform polarization and non-uniform heating.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a pole piece comprises a current collector, wherein at least two layers of active coatings and at least one layer of efficient conductive film are fixedly arranged on two opposite surfaces of the current collector; the active coating and the high-efficiency conductive film are arranged at intervals from the surface of the current collector from inside to outside, and the outermost layer is the active coating.
Furthermore, the thickness of the high-efficiency conductive film is between 0.1 and 5 mu m.
Furthermore, all the high-efficiency conductive films are bonded with the current collector in parallel.
Further, the high-efficiency conductive film is a first conductive agent coating.
Preferably, the first conductive agent is a conductive inorganic substance or a conductive organic substance having delocalized large pi-bond characteristics.
More preferably, the first conductive agent is one or more of carbon nanotubes, graphene, vapor deposition carbon fibers, conductive graphite, conductive carbon black, polyacetylene, polythiophene, polypyrrole, polyaniline, polyphenylene ethylene and polydiyne.
More preferably, the first conductive agent is a mixture of carbon nanotubes and graphene.
Further, the high-efficiency conductive film coating also comprises a first binder; the weight ratio of the first conductive agent to the first binder is (100-95): 0.01-5.
Preferably, the first binder is one or more of polytetrafluoroethylene, carboxymethyl cellulose, styrene-butadiene rubber, polyimide, polypropionic acid, polyacrylonitrile and polyvinylpyrrolidone.
Furthermore, the forming mode of the high-efficiency conductive film on the surface of the active coating is one of gravure printing, screen printing, extrusion coating, chemical vapor deposition and magnetron sputtering.
Furthermore, the pole piece is a positive pole piece, and the current collector is an aluminum foil.
Further, the active coating layer is a mixture coating layer of the positive electrode active material, the second conductive agent and the second binder.
Preferably, the positive active material is one of lithium nickel cobalt manganese oxide, lithium cobaltate, lithium manganate, lithium iron phosphate and lithium manganese phosphate; the second conductive agent is one or more of conductive carbon black, carbon nano tubes and graphene; the second binder is one or more of polytetrafluoroethylene, polyimide, polypropionic acid and polyacrylonitrile.
Furthermore, the pole piece is a negative pole piece, and the current collector is a copper foil.
Further, the active coating layer is a mixture coating layer of the negative electrode active material, the third conductive agent, and the third binder.
Preferably, the negative active substance is one or more of a graphite material, a silicon-based material and lithium titanate; the third conductive agent is one or more of conductive carbon black, carbon nano tubes and graphene; the third binder is one or more of carboxymethyl cellulose, styrene-butadiene rubber, polyimide, polypropionic acid and polyacrylonitrile.
The invention also relates to the application of the pole piece in the production of the battery.
The invention further aims to provide a lithium ion battery with low temperature rise and long service life, so that the lithium ion battery with the characteristics of low temperature rise and long cycle can be obtained by applying the pole piece.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
the utility model provides a low temperature rises long-life lithium ion battery, includes positive pole piece, diaphragm and negative pole piece, positive pole piece is as above pole piece when active coating adopts the mixture coating of anodal active material, second conductive agent and second binder, the negative pole piece is as above pole piece when active coating adopts the mixture coating of negative pole active material, third conductive agent and third binder.
Further, the diaphragm is a PE diaphragm.
Compared with the prior art, the pole piece has the following advantages:
(1) the presence of the highly efficient conductive film can make the current density distribution in the vicinity of the conductive film inside the coating more uniform, reducing uneven polarization and uneven heating.
(2) Each layer of high-efficiency conductive film is bonded with the current collector in parallel, so that ohmic polarization of the coating layer in the direction perpendicular to the current collector can be reduced, and current and heat can be conducted.
(3) The temperature inside the pole piece is distributed more uniformly, and the pole piece is used for a battery, so that the charging and discharging temperature rise of the lithium ion battery can be obviously reduced, and the service life of the lithium ion battery is prolonged.
The application of the pole piece in battery production, and the low-temperature-rise long-life lithium ion battery of the pole piece have the same advantages as the pole piece in the prior art, and are not repeated.
Drawings
Fig. 1 is a schematic structural view of a positive electrode tab or a negative electrode tab in example 1 and a negative electrode tab in example 3;
FIG. 2 is a schematic structural view of the positive electrode tab or the negative electrode tab in example 2;
FIG. 3 is a schematic structural view of a positive electrode tab in example 3;
fig. 4 is a schematic diagram of a cell structure in embodiment 1;
fig. 5 is a schematic diagram of a cell structure in embodiment 2;
fig. 6 is a schematic diagram of a cell structure in embodiment 3;
fig. 7 is a schematic diagram of the cell structure of comparative example 1 or comparative example 2.
Reference numerals:
1-current collector; 2-a first reactive coating; 3-a first high efficiency conductive film; 4-a second reactive coating; 5-a second high efficiency conductive film; 6-a third reactive coating; 7-a third high efficiency conductive film; 8-a fourth reactive coating; 9-a diaphragm; 10-positive pole piece; 11-negative pole piece.
Detailed Description
Unless defined otherwise, technical terms used in the following examples have the same meanings as commonly understood by one of ordinary skill in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional chemical reagents; the experimental methods are conventional methods unless otherwise specified.
A pole piece comprises a current collector, wherein at least two layers of active coatings and at least one layer of efficient conductive film are fixedly arranged on two opposite surfaces of the current collector; the active coating and the high-efficiency conductive film are arranged at intervals from the surface of the current collector from inside to outside, and the outermost layer is the active coating.
Wherein the thickness of the high-efficiency conductive film is between 0.1 and 5 mu m.
All the high-efficiency conductive films are bonded with the current collector in parallel, and can conduct current and heat.
The high-efficiency conductive film is a first conductive agent coating, wherein the first conductive agent is not limited to a conductive inorganic substance with the characteristic of delocalized large pi-shaped bonds, such as carbon nano tubes, graphene, vapor-deposited carbon fibers, conductive graphite and conductive carbon black, or a conductive organic substance, such as one or a combination of polyacetylene, polythiophene, polypyrrole, polyaniline, polyphenylene ethylene and polydiyne. More preferably, the first conductive agent is a mixture of carbon nanotubes and graphene.
In some cases, the high efficiency conductive film may further include a first binder in addition to the first conductive agent, and in this case, the weight ratio of the first conductive agent to the first binder is (100-95): (0.01-5). The first binder is not limited to one or a combination of several of polytetrafluoroethylene, carboxymethyl cellulose, styrene butadiene rubber, polyimide, polypropionic acid, polyacrylonitrile, polyvinylpyrrolidone, and the like.
The forming method of the high-efficiency conductive film on the surface of the active coating is but not limited to one of gravure printing, screen printing, extrusion coating, chemical vapor deposition and magnetron sputtering.
The pole piece can be used as a positive pole piece and a negative pole piece. When the lithium ion battery is used as a positive pole piece, the current collector adopts an aluminum foil; the active coating layer is a coating layer of a mixture (i.e., a positive electrode slurry) of a positive electrode active material, a second conductive agent, and a second binder. The positive active material is not limited to one or more of materials with lithium ion removal function, such as nickel cobalt lithium manganate, lithium cobaltate, lithium manganate, lithium iron phosphate, lithium manganese phosphate and the like; the second conductive agent is not limited to one or more of conductive carbon black, carbon nanotubes, graphene and other materials with high electronic conductivity; the second binder is not limited to one or more of polytetrafluoroethylene, polyimide, polypropionic acid, polyacrylonitrile and other high molecular compounds with binding effect.
When the pole piece is used as a negative pole piece, the current collector adopts copper foil; the active coating layer is a coating layer of a mixture (i.e., negative electrode slurry) of a negative electrode active material, a third conductive agent, and a third binder. The negative electrode active substance is not limited to one or more of graphite materials, silicon-based materials, lithium titanate and other materials with a lithium ion intercalation function; the third conductive agent is not limited to one or more of conductive carbon black, carbon nanotubes, graphene and other materials with high electronic conductivity; the third binder is not limited to one or more of carboxymethyl cellulose, styrene-butadiene rubber, polyimide, polypropionic acid, polyacrylonitrile and other high-molecular compounds with adhesive action.
It should be noted that, the high-efficiency conductive film, according to the working principle of the lithium ion battery, the battery of the last embodiment can work, and the temperature rise and the cycle performance are superior to those of the comparative example, which indicates that the film can permeate Li +, i.e. the film has the porous function, and is actually a high-efficiency conductive porous film, and the reduction of the temperature rise indicates that the reduction of the ohmic resistance is due to the high-efficiency conductivity of the film. The high-efficiency conductive film of the invention is essentially a high-efficiency conductive porous film, as mentioned above, which has two completely different functions with the porous diaphragm, the diaphragm is a key component for forming the battery, and plays a role in insulating the positive electrode and the negative electrode, and the battery structure can not be lost, and the battery can still work even if the high-efficiency conductive porous film (namely the high-efficiency conductive film) is not used; two conductive agents such as carbon nano tubes and graphene are directly adopted, and the current density from the current collector to the surface of the pole piece in the direction perpendicular to the current collector inside the pole piece is gradually reduced; and the high-efficiency conductive film is embedded into the pole piece (see schematic diagram 1, the conventional pole piece is a uniform body, the uniform body is layered, and the high-efficiency conductive film is embedded between layers) and is connected with the current collector (the tail end of each high-efficiency conductive film is bonded and fixed with the surface of the current collector, namely in parallel connection), so that the problem of current density reduction can be solved.
The pole piece can be used for producing batteries, such as a positive pole and/or a negative pole.
The utility model provides a low temperature rises long-life lithium ion battery, includes positive pole piece, diaphragm and negative pole piece, positive pole piece is as above pole piece when active coating adopts the mixture coating of anodal active material, second conductive agent and second binder, the negative pole piece is as above pole piece when active coating adopts the mixture coating of negative pole active material, third conductive agent and third binder. The separator may be a PE separator or the like.
The terms "first", "second" and "third" in the above-mentioned "first conductive agent", "second conductive agent", "third conductive agent", "first adhesive", "second adhesive", "third adhesive" and the like are merely used for the purpose of distinguishing the respective conductive agents or adhesives from each other in terms of expression, and are substantially the conductive agents and adhesives applied to the respective cases.
The present invention will be described in detail with reference to the following examples and accompanying drawings.
Example 1
The utility model provides a pole piece, the structure is shown in figure 1, including the mass flow body 1, 1 upper surface of the mass flow body and lower surface all are equipped with first active coating 2, and 2 outer surface claddings of first active coating have first high-efficient conductive film 3, and 3 ends of first high-efficient conductive film all bond parallelly connected with 1 surface of the mass flow body, and 1 side surface of the mass flow body is kept away from to 3 outer surfaces of first high-efficient conductive film all is equipped with second active coating 4.
The pole piece can be used as a positive pole piece 10 when the first active coating 2 and the second active coating 4 are both coated with a mixture of a positive active material, a second conductive agent and a second binder, and can be used as a negative pole piece 11 when the first active coating 2 and the second active coating 4 are both coated with a mixture of a negative active material, a third conductive agent and a third binder. The specific manufacturing method comprises the following steps:
manufacturing a positive pole piece (namely a positive pole piece) with the composite coating:
a. pouring N-methyl-2-pyrrolidone into a positive active substance NCM622, a conductive agent 1(SP), a conductive agent 2(CNTs) and a binder (PVDF) according to a weight ratio of 96:1:1:2, mixing and uniformly stirring to prepare positive slurry A with a solid content of 75%;
b. pouring N-methyl-2-pyrrolidone into a conductive agent 1 (CNTs-carbon nano tubes), a conductive agent 2 (GNs-graphene) and a binder (PVDF) according to the weight ratio of 48:48:4, mixing, stirring and dispersing uniformly to prepare a high-efficiency conductive slurry B with the solid content of 7.5%;
c. coating the anode slurry A on the upper surface and the lower surface of an aluminum foil current collector 1, and drying to obtain a coating with the total load of 20mg/cm2Forming a first active coating 2 to obtain a positive pole piece A;
d. printing the high-efficiency conductive paste B on the upper surface and the lower surface of the positive pole piece A through gravure to form a first high-efficiency conductive film 3, and controlling the thickness of the first high-efficiency conductive film 3 to be 1-3 mu m to obtain a composite positive pole piece B;
e. coating the positive electrode slurry A on the upper surface and the lower surface of the composite positive electrode sheet B, and drying to obtain a coating with the total load of 40mg/cm2Forming a second active coating 4 to obtain a composite positive pole piece C;
f. and (3) rolling the composite positive pole piece C to the thickness of 125 μm to obtain the target positive pole piece 10, wherein the structure is schematically shown in figure 1.
Manufacturing a negative electrode composite coating pole piece (namely, a negative electrode pole piece):
a. mixing a negative active material artificial graphite, a conductive agent (SP), a thickening agent carboxymethylcellulose sodium (CMC) and a binder Styrene Butadiene Rubber (SBR) according to a weight ratio of 94.5: 1.5: 1.5: 2.5, adding water, stirring and mixing uniformly to obtain negative electrode slurry A with the solid content of 50%;
b. adding water into a conductive agent 1 (CNTs-carbon nano tubes), a conductive agent 2 (GNs-graphene) and a binder (CMC) according to a weight ratio of 52:45:3, mixing, stirring and dispersing uniformly to prepare a high-efficiency conductive slurry B with a solid content of 7%.
c. Coating the negative electrode slurry A on the upper surface and the lower surface of a copper foil current collector 1, and drying to coat the total loadThe amount is 12mg/cm2Forming a first active coating 2 to obtain a negative pole piece A;
d. printing the high-efficiency conductive paste B on the upper surface and the lower surface of the negative pole piece A through gravure to form a first high-efficiency conductive film 3, and controlling the thickness of the first high-efficiency conductive film 3 to be 1-3 mu m to obtain a composite negative pole piece B;
e. coating the negative electrode slurry A on the upper surface and the lower surface of the composite negative electrode pole piece B, and drying to obtain a coating with a total load of 24mg/cm2Forming a second active coating 4 to obtain a composite negative pole piece C;
f. and (3) rolling the composite negative pole piece C to the thickness of 155 mu m to obtain the target negative pole piece 11, wherein the structure is schematically shown in figure 1.
Manufacturing the lithium ion battery:
a. the positive pole piece 10, the negative pole piece 11 and the PE diaphragm 9 which are prepared by the process are made into a battery core in a winding or laminating mode, and the local structure is shown in figure 4;
b. preparing an electrolyte: 1mol/L LiPF6, wherein the mass ratio of the solvent is EC (ethylene carbonate): DMC (dimethyl carbonate): EMC (methyl ethyl carbonate) ═ 5: 2: 3, 1 wt% VC (vinylene carbonate), 1 wt% FEC (fluoroethylene carbonate), 1 wt% 1,3-PS (1, 3-propane sultone);
c. and injecting the electrolyte into the prepared battery core, standing, pre-charging and performing related electrical performance tests.
Example 2
A pole piece is structurally shown in figure 2 and comprises a current collector 1, wherein the upper surface and the lower surface of the current collector 1 are respectively provided with a first active coating 2, the outer surface of each first active coating 2 is coated with a first efficient conductive film 3, the tail end of each first efficient conductive film 3 is bonded with the surface of the current collector 1 in parallel, and the surface of one side, away from the current collector 1, of the outer surface of each first efficient conductive film 3 is provided with a second active coating 4; a second high-efficiency conductive film 5 is coated outside the second active coating 4, and the tail ends of the second high-efficiency conductive films 5 are adhered to the surface of the current collector 1 in parallel; and the surface of one side of the outer surface of the second high-efficiency conductive film 5, which is far away from the current collector 1, is provided with a third active coating 6.
When the first active coating 2, the second active coating 4 and the third active coating 6 are all mixed coatings of a positive active material, a second conductive agent and a second binder, the pole piece can be used as a positive pole piece 10, and when the first active coating 2, the second active coating 4 and the third active coating 6 are all mixed coatings of a negative active material, a third conductive agent and a third binder, the pole piece can be used as a negative pole piece 11. The specific manufacturing method comprises the following steps:
manufacturing a positive pole piece (namely a positive pole piece) with the composite coating:
a. pouring N-methyl-2-pyrrolidone into a positive active substance NCM622, a conductive agent 1(SP), a conductive agent 2(CNTs) and a binder (PVDF) according to a weight ratio of 96:1:1:2, mixing and uniformly stirring to prepare positive slurry A with a solid content of 75%;
b. pouring N-methyl-2-pyrrolidone into a conductive agent 1 (CNTs-carbon nano tubes), a conductive agent 2 (GNs-graphene) and a binder (PVDF) according to the weight ratio of 52:45:3, mixing, stirring, and dispersing uniformly at a high speed to prepare a high-efficiency conductive slurry B with the solid content of 7.5%;
c. coating the anode slurry A on the upper surface and the lower surface of an aluminum foil current collector 1, and drying to obtain a coating with the total load of 15mg/cm2Forming a first active coating 2 to obtain a positive pole piece A;
d. printing the high-efficiency conductive paste B on the upper surface and the lower surface of the positive pole piece A through gravure to form a first high-efficiency conductive film 3, and controlling the thickness of the first high-efficiency conductive film 3 to be 1-3 mu m to obtain a composite positive pole piece B;
e. coating the positive electrode slurry A on the upper surface and the lower surface of the composite positive electrode sheet B, and drying to obtain a coating with the total load of 30mg/cm2Forming a second active coating 4 to obtain a composite positive pole piece C;
f. printing the high-efficiency conductive paste B on the upper surface and the lower surface of the positive pole piece C through a gravure to form a second high-efficiency conductive film 5, and controlling the thickness of the second high-efficiency conductive film 5 to be 1-3 mu m to obtain a composite positive pole piece D;
g. coating the positive electrode slurry A on the upper surface and the lower surface of the composite positive electrode plate D, wherein the total loading capacity of the dried coating is 40mg/cm2Forming a third active coating 6 to obtain a composite positive pole piece E;
h. and (3) rolling the composite positive pole piece E to the thickness of 125 mu m to obtain the target positive pole piece 10, wherein the structure is schematically shown in figure 2.
Manufacturing a negative electrode composite coating pole piece (namely, a negative electrode pole piece):
a. mixing a negative active material artificial graphite, a conductive agent (SP), a thickening agent carboxymethylcellulose sodium (CMC) and a binder Styrene Butadiene Rubber (SBR) according to a weight ratio of 94.5: 1.5: 1.5: 2.5, adding water, stirring and mixing uniformly to obtain negative electrode slurry A with the solid content of 50%;
b. adding water into a conductive agent 1 (CNTs-carbon nano tubes), a conductive agent 2 (GNs-graphene) and a binder (CMC) according to a weight ratio of 52:45.5:2.5, mixing, stirring, dispersing uniformly at a high speed, and preparing a high-efficiency conductive slurry B with a solid content of 7%.
c. Coating the negative electrode slurry A on the upper surface and the lower surface of a copper foil current collector 1, and drying to obtain a coating with the total load of 8mg/cm2Forming a first active coating 2 to obtain a negative pole piece A;
d. printing the high-efficiency conductive paste B on the upper surface and the lower surface of the negative pole piece A through a gravure to form a first high-efficiency conductive film 3, and controlling the thickness of the first high-efficiency conductive film 3 to be 1-3 mu m to obtain a composite negative pole piece B;
e. coating the negative electrode slurry A on the upper surface and the lower surface of the composite negative electrode pole piece B, and drying to obtain a coating with the total load of 16mg/cm2Forming a second active coating 4 to obtain a composite negative pole piece C;
f. printing the high-efficiency conductive paste B on the upper surface and the lower surface of the negative pole piece C through a gravure to form a second high-efficiency conductive film 5, and controlling the thickness of the second high-efficiency conductive film 5 to be 1-3 mu m to obtain a composite negative pole piece D;
g. coating the negative electrode slurry A on the upper surface and the lower surface of the composite negative electrode pole piece D, and drying to obtain a coating with the total load of 24mg/cm2Forming a third active coating 6 to obtain a composite negative pole piece E;
h. and (3) rolling the composite negative pole piece E to the thickness of 155 mu m to obtain a target negative pole piece 11, wherein the structure is schematically shown in figure 2.
Manufacturing the lithium ion battery:
a. the positive pole piece 10, the negative pole piece 11 and the PE diaphragm 9 which are prepared by the process are made into a battery core in a winding or laminating mode, and the local structure is shown in figure 5;
b. preparing an electrolyte: 1mol/L LiPF6, wherein the mass ratio of the solvent is EC: DMC: EMC 5: 2: 3, 1 wt% VC, 1 wt% FEC, 1 wt% 1, 3-PS;
c. and injecting the electrolyte into the prepared battery core, standing, pre-charging and performing related electrical performance tests.
Comparative example 1
Manufacturing a positive pole piece:
a. pouring N-methyl-2-pyrrolidone into a positive active substance NCM622, a conductive agent 1(SP), a conductive agent 2(CNTs) and a binder (PVDF) according to a weight ratio of 96:1:1:2, mixing and uniformly stirring to obtain positive slurry with a solid content of 75%;
b. coating the positive electrode slurry on an aluminum foil current collector 1, wherein the total loading capacity of the dried coating is 40mg/cm2Obtaining a positive pole piece 10;
c. the positive pole piece 10 is rolled to a thickness of 125 μm.
Manufacturing a negative pole piece:
a. mixing a negative active material artificial graphite, a conductive agent (SP), a thickening agent carboxymethylcellulose sodium (CMC) and a binder Styrene Butadiene Rubber (SBR) according to a weight ratio of 94.5: 1.5: 1.5: 2.5, adding water, stirring and mixing uniformly to obtain negative electrode slurry with the solid content of 50%;
b. coating the negative electrode slurry on the upper surface and the lower surface of a copper foil current collector 1, and drying to obtain a coating with a total load of 24mg/cm2Obtaining a negative pole piece 11;
c. the negative pole piece 11 is rolled to a thickness of 155 μm.
Manufacturing the lithium ion battery:
a. the positive pole piece 10, the negative pole piece 11 and the PE diaphragm 9 which are prepared by the process are made into a battery core in a winding or laminating mode, and the local structure is shown in figure 7;
b. preparing an electrolyte: 1mol/L LiPF6, wherein the mass ratio of the solvent is EC: DMC: EMC 5: 2: 3, 1 wt% VC, 1 wt% FEC, 1 wt% 1, 3-PS;
c. and injecting the electrolyte into the prepared battery core, standing, pre-charging and performing related electrical performance tests.
1C/1C charge-discharge cycle test is carried out on example 1, example 2 and comparative example 1 at the temperature of 25 ℃, and gram capacity of the first discharge capacity and capacity retention rate of the battery after 1500 weeks of cycle are recorded; in addition, the cells were subjected to a 6C/4C/2C/1C rate discharge test and the temperature rise under discharge was recorded at different rates (infrared imaging test), and the results are reported in Table 1.
Table 1 test results of example 1, example 2 and comparative example 1
As can be seen from table 1, the rate temperature rise of the example 1 and the example 2 is significantly lower than that of the comparative example 1, the cell surface temperature difference is smaller than that of the comparative example 1, and the cycle retention rate is also significantly higher than that of the comparative example 1.
Example 3
As shown in fig. 1, the structure of the negative electrode tab 11 of this embodiment is the same as that of the tab of embodiment 1; the structure of the positive electrode plate 10 is basically the same as that of the positive electrode plate of the embodiment 2, except that: as shown in fig. 3, the outer surfaces of the third active coatings 6 are also coated with third efficient conductive films 7, and the surfaces of the outer surfaces of the third efficient conductive films 7, which are far away from the current collector 1, are provided with fourth active coatings 8.
The specific manufacturing method of the positive pole piece and the negative pole piece in this embodiment is as follows:
manufacturing a positive pole piece (namely a positive pole piece) with the composite coating:
a. pouring N-methyl-2-pyrrolidone into a positive active material NCM811, a conductive agent 1(SP), a conductive agent 2(CNTs) and a binder (PVDF) according to the weight ratio of 97.9:0.8:0.8:1.5, mixing and uniformly stirring to prepare positive slurry A with the solid content of 75%;
b. pouring N-methyl-2-pyrrolidone into a conductive agent 1 (CNTs-carbon nano tubes), a conductive agent 2 (GNs-graphene), a conductive agent 3 (poly propylamine) and a binder (PVDF) according to the weight ratio of 45:45:9.5:0.5, mixing, stirring and dispersing uniformly to prepare a high-efficiency conductive slurry B with the solid content of 7.5%;
c. coating the anode slurry A on the upper surface and the lower surface of an aluminum foil current collector 1, and drying to obtain a coating with a total load of 8mg/cm2Forming a first active coating 2 to obtain a positive pole piece A;
d. printing the high-efficiency conductive paste B on the upper surface and the lower surface of the positive pole piece A through gravure to form a first high-efficiency conductive film 3, and controlling the thickness of the first high-efficiency conductive film 3 to be 1-3 mu m to obtain a composite positive pole piece B;
e. coating the positive electrode slurry A on the upper surface and the lower surface of the composite positive electrode plate B to form a second active coating 4, wherein the total load of the dried coating is 16mg/cm2Obtaining a composite positive pole piece C;
f. printing the high-efficiency conductive paste B on the upper surface and the lower surface of the positive pole piece C through a gravure to form a second high-efficiency conductive film 5, and controlling the thickness of the second high-efficiency conductive film 5 to be 1-3 mu m to obtain a composite positive pole piece D;
g. coating the positive electrode slurry A on the upper surface and the lower surface of the composite positive electrode plate D, wherein the total loading capacity of the dried coating is 24mg/cm2Forming a third active coating 6 to obtain a composite positive pole piece E;
h. printing the high-efficiency conductive paste B on the upper surface and the lower surface of the composite positive pole piece E through a gravure to form a third high-efficiency conductive film 7, and controlling the thickness of the third high-efficiency conductive film 7 to be 1-3 mu m to obtain a composite positive pole piece F;
i. coating the positive electrode slurry A on the upper surface and the lower surface of the composite positive electrode piece F, wherein the total loading capacity of the dried coating is 32mg/cm2Forming a fourth active coating 8 to obtain a composite positive pole piece G;
j. and (3) rolling the composite positive pole piece G to the thickness of 120 mu m to obtain the target positive pole piece 10, wherein the structure is schematically shown in figure 3.
Manufacturing a negative electrode composite coating pole piece (namely, a negative electrode pole piece):
a. preparing negative active material artificial graphite, a conductive agent (SP), a thickening agent carboxymethylcellulose sodium (CMC) and a binder Styrene Butadiene Rubber (SBR) according to a weight ratio of 95.5: 1.0: 1.3: 2.2, adding water, stirring and mixing uniformly to obtain negative electrode slurry A with the solid content of 50%;
b. adding water into a conductive agent 1 (CNTs-carbon nano tubes), a conductive agent 2 (GNs-graphene) and a binder (CMC) according to a weight ratio of 42:42:16, mixing, stirring, dispersing uniformly at a high speed, and preparing a high-efficiency conductive slurry B with a solid content of 7%.
c. Coating the negative electrode slurry A on the upper surface and the lower surface of a copper foil current collector 1, and drying to obtain a coating with the total load of 10mg/cm2Forming a first active coating 2 to obtain a negative pole piece A;
d. printing the high-efficiency conductive paste B on the upper surface and the lower surface of the negative pole piece A through a gravure to form a first high-efficiency conductive film 3, and controlling the thickness of the first high-efficiency conductive film 3 to be 1-3 mu m to obtain a composite negative pole piece B;
e. coating the negative electrode slurry A on the upper surface and the lower surface of the composite negative electrode pole piece B, and drying to obtain a coating with the total load of 20mg/cm2Forming a second active coating 4 to obtain a composite negative pole piece C;
f. and (3) rolling the composite negative pole piece C to the thickness of 148 mu m to obtain the target negative pole piece 11, wherein the structure is schematically shown in figure 1.
Manufacturing the lithium ion battery:
a. the positive pole piece 10, the negative pole piece 11 and the PE diaphragm 9 which are prepared by the process are made into a battery core in a winding or laminating mode, and the local structure is shown in figure 6;
b. preparing an electrolyte: 1mol/L LiPF6, wherein the mass ratio of the solvent is EC: DMC: EMC 5: 2: 3, 1 wt% VC, 1 wt% FEC, 1 wt% 1, 3-PS;
c. and injecting the electrolyte into the prepared battery core, standing, pre-charging and performing related electrical performance tests.
Comparative example 2
Manufacturing a positive pole piece:
a. pouring N-methyl-2-pyrrolidone into a positive active material NCM622, a conductive agent 1(SP), a conductive agent 2(CNTs) and a binder (PVDF) according to the weight ratio of 97.9:0.8:0.8:1.5, mixing and uniformly stirring to prepare positive slurry with the solid content of 75%;
b. coating the positive electrode slurry onThe total loading of the coating after drying on the aluminum foil current collector 1 is 40mg/cm2Obtaining a positive pole piece 10;
c. the positive pole piece 10 is rolled to a thickness of 125 μm.
Manufacturing a negative pole piece:
a. preparing negative active material artificial graphite, a conductive agent (SP), a thickening agent carboxymethylcellulose sodium (CMC) and a binder Styrene Butadiene Rubber (SBR) according to a weight ratio of 95.5: 1.0: 1.3: 2.2, adding water, stirring and mixing uniformly to obtain negative electrode slurry with the solid content of 50%;
b. coating the negative electrode slurry on a copper foil current collector 1, and drying to obtain a coating with a total load of 24mg/cm2Obtaining a negative pole piece 11;
c. the negative pole piece 11 is rolled to a thickness of 155 μm.
Manufacturing the lithium ion battery:
a. the positive pole piece 10, the negative pole piece 11 and the PE diaphragm 9 which are prepared by the process are made into a battery core in a winding or laminating mode, and the local structure is shown in figure 7;
b. preparing an electrolyte: 1mol/L LiPF6, wherein the mass ratio of the solvent is EC: DMC: EMC 5: 2: 3, 1 wt% VC, 1 wt% FEC, 1 wt% 1, 3-PS;
c. and injecting the electrolyte into the prepared battery core, standing, pre-charging and performing related electrical performance tests.
1C/1C charge-discharge cycle test is carried out on the example 3 and the comparative example 2 respectively under the temperature condition of 25 ℃, and gram capacity of the first discharge capacity and capacity retention rate of the battery after 1500-week-long cycle are recorded; in addition, the cells were subjected to a 6C/4C/2C/1C rate discharge test and the temperature rise under discharge was recorded at different rates (infrared imaging test), and the results are reported in Table 2.
Table 2 example 3 and comparative example 2 test results
As can be seen from Table 2, the rate temperature rise of example 3 is significantly lower than that of comparative example 2, the surface temperature difference of the battery cell is smaller than that of comparative example 2, and the cycle retention rate is also significantly higher than that of comparative example 2.
Finally, it should be further noted that "the first", "the second", "the third", and "the fourth" in the first active coating, the first high-efficiency conductive film, the second active coating, the second high-efficiency conductive film, the third active coating, the third high-efficiency conductive film, and the fourth active coating are only for artificially dividing the structural layer, and essentially in each pole piece structure, the active coating and the high-efficiency conductive film are also corresponding to each other.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A pole piece, characterized by: the current collector comprises a current collector, wherein at least two active coatings and at least one efficient conductive film are fixedly arranged on two opposite surfaces of the current collector; the active coating and the high-efficiency conductive film are arranged at intervals from the surface of the current collector from inside to outside, and the outermost layer is the active coating.
2. The pole piece of claim 1, wherein: the thickness of the high-efficiency conductive film is between 0.1 and 5 mu m;
and/or all the high-efficiency conductive films are bonded with the current collector in parallel.
3. The pole piece of claim 1 or 2, wherein: the high-efficiency conductive film is a first conductive agent coating;
preferably, the first conductive agent is a conductive inorganic substance or a conductive organic substance with delocalized big pi-bond characteristics;
more preferably, the first conductive agent is one or more of carbon nanotubes, graphene, vapor deposition carbon fibers, conductive graphite, conductive carbon black, polyacetylene, polythiophene, polypyrrole, polyaniline, polyphenylene ethylene and polydiyne;
more preferably, the first conductive agent is a mixture of carbon nanotubes and graphene.
4. The pole piece of claim 3, wherein: the high-efficiency conductive film coating also comprises a first binder; the weight ratio of the first conductive agent to the first binder is (100-95): 0.01-5.
5. The pole piece of claim 4, wherein: the first binder is one or more of polytetrafluoroethylene, carboxymethyl cellulose, styrene butadiene rubber, polyimide, polypropionic acid, polyacrylonitrile and polyvinylpyrrolidone.
6. The pole piece of any one of claims 1 to 5, wherein: the forming mode of the high-efficiency conductive film on the surface of the active coating is one of gravure printing, screen printing, extrusion coating, chemical vapor deposition and magnetron sputtering.
7. The pole piece of any one of claims 1 to 6, wherein: the pole piece is a positive pole piece, and the current collector is an aluminum foil;
and/or the active coating is a mixture coating of a positive electrode active material, a second conductive agent and a second binder;
preferably, the positive active material is one of lithium nickel cobalt manganese oxide, lithium cobaltate, lithium manganate, lithium iron phosphate and lithium manganese phosphate; the second conductive agent is one or more of conductive carbon black, carbon nano tubes and graphene; the second binder is one or more of polytetrafluoroethylene, polyimide, polypropionic acid and polyacrylonitrile.
8. The pole piece of any one of claims 1 to 6, wherein: the pole piece is a negative pole piece, and the current collector is copper foil;
and/or the active coating is a mixture coating of a negative electrode active material, a third conductive agent and a third binder;
preferably, the negative active substance is one or more of a graphite material, a silicon-based material and lithium titanate; the third conductive agent is one or more of conductive carbon black, carbon nano tubes and graphene; the third binder is one or more of carboxymethyl cellulose, styrene-butadiene rubber, polyimide, polypropionic acid and polyacrylonitrile.
9. Use of a pole piece according to any one of claims 1 to 8 in the production of a battery.
10. The utility model provides a low temperature rise long-life lithium ion battery, includes positive pole piece, diaphragm and negative pole piece, its characterized in that: the positive pole piece is the pole piece of any one of claims 1 to 7, and the negative pole piece is the pole piece of any one of claims 1 to 6 or claim 8;
and/or the membrane is a PE membrane.
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CN113161510A (en) * | 2021-03-22 | 2021-07-23 | 欣旺达电动汽车电池有限公司 | Electrode pole piece, preparation method thereof and lithium ion battery |
CN113555522A (en) * | 2021-07-21 | 2021-10-26 | 珠海冠宇电池股份有限公司 | Pole piece and battery |
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CN109309191A (en) * | 2017-07-26 | 2019-02-05 | 成都特隆美储能技术有限公司 | A kind of novel long-life energy storage lithium ion battery pole piece and lithium ion battery |
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CN112599782A (en) * | 2020-12-16 | 2021-04-02 | 凤凰浩然科技有限公司 | Quick-charging lithium ion battery |
CN113161510A (en) * | 2021-03-22 | 2021-07-23 | 欣旺达电动汽车电池有限公司 | Electrode pole piece, preparation method thereof and lithium ion battery |
CN113555522A (en) * | 2021-07-21 | 2021-10-26 | 珠海冠宇电池股份有限公司 | Pole piece and battery |
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