CN109411701A - Battery anode slice and its manufacturing method and lithium ion battery and its manufacturing method - Google Patents
Battery anode slice and its manufacturing method and lithium ion battery and its manufacturing method Download PDFInfo
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- CN109411701A CN109411701A CN201811071996.XA CN201811071996A CN109411701A CN 109411701 A CN109411701 A CN 109411701A CN 201811071996 A CN201811071996 A CN 201811071996A CN 109411701 A CN109411701 A CN 109411701A
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- positive electrode
- plate
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 101
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 101
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 45
- 238000000576 coating method Methods 0.000 claims abstract description 114
- 239000011248 coating agent Substances 0.000 claims abstract description 112
- 239000006258 conductive agent Substances 0.000 claims abstract description 111
- 229910052751 metal Inorganic materials 0.000 claims abstract description 98
- 239000002184 metal Substances 0.000 claims abstract description 98
- 239000000758 substrate Substances 0.000 claims abstract description 81
- 239000011883 electrode binding agent Substances 0.000 claims abstract description 26
- 239000007774 positive electrode material Substances 0.000 claims abstract description 26
- 239000000463 material Substances 0.000 claims abstract description 16
- 239000011247 coating layer Substances 0.000 claims description 44
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 42
- 239000011265 semifinished product Substances 0.000 claims description 42
- 239000011267 electrode slurry Substances 0.000 claims description 35
- 239000000375 suspending agent Substances 0.000 claims description 31
- 238000003466 welding Methods 0.000 claims description 31
- 239000012298 atmosphere Substances 0.000 claims description 30
- 239000013067 intermediate product Substances 0.000 claims description 28
- 239000003792 electrolyte Substances 0.000 claims description 27
- 239000007787 solid Substances 0.000 claims description 27
- 238000001035 drying Methods 0.000 claims description 22
- 239000011888 foil Substances 0.000 claims description 21
- 239000000243 solution Substances 0.000 claims description 21
- 238000005520 cutting process Methods 0.000 claims description 18
- 238000002156 mixing Methods 0.000 claims description 18
- 238000005096 rolling process Methods 0.000 claims description 18
- 239000013543 active substance Substances 0.000 claims description 17
- 239000003292 glue Substances 0.000 claims description 17
- 239000007773 negative electrode material Substances 0.000 claims description 17
- 239000006257 cathode slurry Substances 0.000 claims description 16
- 229910002804 graphite Inorganic materials 0.000 claims description 16
- 239000010439 graphite Substances 0.000 claims description 16
- -1 polypropylene Polymers 0.000 claims description 16
- 239000008367 deionised water Substances 0.000 claims description 15
- 229910021641 deionized water Inorganic materials 0.000 claims description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 230000001070 adhesive effect Effects 0.000 claims description 14
- 239000006256 anode slurry Substances 0.000 claims description 14
- 239000002041 carbon nanotube Substances 0.000 claims description 14
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 14
- 239000000853 adhesive Substances 0.000 claims description 13
- 229910052782 aluminium Inorganic materials 0.000 claims description 13
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 13
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 13
- 239000002904 solvent Substances 0.000 claims description 13
- 238000004804 winding Methods 0.000 claims description 13
- 238000000034 method Methods 0.000 claims description 12
- OTYYBJNSLLBAGE-UHFFFAOYSA-N CN1C(CCC1)=O.[N] Chemical compound CN1C(CCC1)=O.[N] OTYYBJNSLLBAGE-UHFFFAOYSA-N 0.000 claims description 11
- 238000012545 processing Methods 0.000 claims description 11
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 10
- 239000011230 binding agent Substances 0.000 claims description 10
- 239000011889 copper foil Substances 0.000 claims description 10
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 10
- 239000004743 Polypropylene Substances 0.000 claims description 9
- 229920001155 polypropylene Polymers 0.000 claims description 9
- 239000002033 PVDF binder Substances 0.000 claims description 8
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical group [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 claims description 8
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 8
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 claims description 8
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 claims description 8
- 239000004698 Polyethylene Substances 0.000 claims description 7
- 238000007600 charging Methods 0.000 claims description 7
- 229920000573 polyethylene Polymers 0.000 claims description 7
- 229920003048 styrene butadiene rubber Polymers 0.000 claims description 7
- 229910019142 PO4 Inorganic materials 0.000 claims description 6
- 239000002131 composite material Substances 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 239000010452 phosphate Substances 0.000 claims description 6
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 6
- 238000007789 sealing Methods 0.000 claims description 6
- 230000003213 activating effect Effects 0.000 claims description 5
- 238000007581 slurry coating method Methods 0.000 claims description 5
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 4
- 239000003013 cathode binding agent Substances 0.000 claims description 4
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 4
- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 claims description 3
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 3
- 229910001367 Li3V2(PO4)3 Inorganic materials 0.000 claims description 3
- 229910052493 LiFePO4 Inorganic materials 0.000 claims description 3
- 229910000668 LiMnPO4 Inorganic materials 0.000 claims description 3
- 229910014985 LiMnxFe1-xPO4 Inorganic materials 0.000 claims description 3
- 229910014982 LiMnxFe1−xPO4 Inorganic materials 0.000 claims description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 3
- 229920002125 Sokalan® Polymers 0.000 claims description 3
- 239000004917 carbon fiber Substances 0.000 claims description 3
- 229910021389 graphene Inorganic materials 0.000 claims description 3
- 239000010410 layer Substances 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 239000000661 sodium alginate Substances 0.000 claims description 3
- 235000010413 sodium alginate Nutrition 0.000 claims description 3
- 229940005550 sodium alginate Drugs 0.000 claims description 3
- 239000011884 anode binding agent Substances 0.000 claims description 2
- 239000004584 polyacrylic acid Substances 0.000 claims description 2
- 239000008151 electrolyte solution Substances 0.000 claims 1
- 230000008901 benefit Effects 0.000 abstract description 9
- 150000003016 phosphoric acids Chemical class 0.000 abstract 2
- 239000003795 chemical substances by application Substances 0.000 abstract 1
- 238000012360 testing method Methods 0.000 description 23
- 229910000831 Steel Inorganic materials 0.000 description 15
- 239000010959 steel Substances 0.000 description 15
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical group [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 14
- 239000002002 slurry Substances 0.000 description 13
- 230000014759 maintenance of location Effects 0.000 description 12
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 9
- 239000000843 powder Substances 0.000 description 9
- 230000009286 beneficial effect Effects 0.000 description 8
- 238000005056 compaction Methods 0.000 description 8
- 229910052759 nickel Inorganic materials 0.000 description 7
- 238000004806 packaging method and process Methods 0.000 description 7
- 238000007747 plating Methods 0.000 description 7
- 238000002360 preparation method Methods 0.000 description 7
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 6
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 6
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 6
- 238000007599 discharging Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 5
- 239000002174 Styrene-butadiene Substances 0.000 description 4
- 238000013461 design Methods 0.000 description 4
- 230000008569 process Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000008595 infiltration Effects 0.000 description 3
- 238000001764 infiltration Methods 0.000 description 3
- 238000010998 test method Methods 0.000 description 3
- 230000004913 activation Effects 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 239000010405 anode material Substances 0.000 description 2
- 239000010406 cathode material Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000010281 constant-current constant-voltage charging Methods 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 239000003273 ketjen black Substances 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 239000002969 artificial stone Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000002134 carbon nanofiber Substances 0.000 description 1
- 239000004567 concrete Substances 0.000 description 1
- 238000010280 constant potential charging Methods 0.000 description 1
- 238000010277 constant-current charging Methods 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000002003 electrode paste Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 238000012858 packaging process Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
Classifications
-
- 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
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
-
- 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
- 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
- H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
-
- 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
- H01M4/1397—Processes of manufacture of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
-
- 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
-
- 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/621—Binders
- H01M4/622—Binders being polymers
- H01M4/623—Binders being polymers fluorinated polymers
-
- 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
-
- 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
- H01M4/64—Carriers or collectors
- H01M4/70—Carriers or collectors characterised by shape or form
- H01M4/72—Grids
-
- 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
-
- 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
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Crystallography & Structural Chemistry (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Secondary Cells (AREA)
Abstract
The present invention is suitable for field of batteries, discloses the manufacturing method of battery anode slice, the manufacturing method of battery anode slice, lithium ion battery and lithium ion battery, wherein the width of battery anode slice is 65mm ± 5mm；Battery anode slice include cathode metal substrate, with cathode metal substrate be conductively connected anode ear and coated on cathode metal substrate outside positive coating, positive coating includes the component of following parts by weight: positive active material 88.0%-98.6%；Positive electrode binder 1.0%-7.0%；Positive conductive agent 0.4%-14.0%；Positive active material is phosphoric acid salt material, and positive conductive agent includes at least one of the agent of graininess positive conductive and fibrous positive conductive agent.In the present invention, positive active material uses phosphoric acid salt material, and battery capacity reaches 2000mAh, and it also has the advantages that long circulation life, high rate performance are prominent, security performance is reliable.
Description
Technical Field
The invention relates to the field of batteries, in particular to a battery positive plate, a manufacturing method of the battery positive plate, a lithium ion battery with the battery positive plate and a manufacturing method of the lithium ion battery.
Background
With the continuous development of the lithium ion battery industry, 18650 lithium ion batteries (with the battery diameter of 18mm and the battery height of 65mm) become the preferred model in the field of battery packaging due to the standardized size and flexible grouping mode. In the prior art, the width of a 18650 type lithium ion battery positive plate is 55mm-56mm, however, due to the limitation of the technical level of lithium battery raw materials, the 18650 type lithium ion battery has limited capacity and low energy density, is difficult to promote, and is difficult to meet the requirement of the market on the battery capacity.
Disclosure of Invention
The first purpose of the invention is to provide a battery positive plate, which aims to solve the technical problem of small capacity of the existing lithium ion battery.
In order to achieve the purpose, the invention provides the following scheme: the battery positive plate is 65mm +/-5 mm in width, the battery positive plate comprises a positive metal substrate, a positive lug in conductive connection with the positive metal substrate and a positive coating coated outside the positive metal substrate, and the positive coating comprises the following components in parts by weight:
88.0% -98.6% of positive active material;
1.0-7.0% of positive electrode binder;
0.4% -14.0% of positive electrode conductive agent;
the positive electrode active substance is a phosphate material, and the positive electrode conductive agent comprises at least one of a granular positive electrode conductive agent and a fibrous positive electrode conductive agent.
Optionally, the positive electrode coating comprises the following components in parts by weight: 94.8% of positive electrode active material; 1.0% of granular positive electrode conductive agent; 1.2% of fibrous positive electrode conductive agent; 3.0% of positive electrode binder; or,
the anode coating comprises the following components in parts by weight: 95.3% of positive electrode active material; 0.9% of granular positive electrode conductive agent; 1.0% of fibrous positive electrode conductive agent; 2.8% of a positive electrode binder; or,
the anode coating comprises the following components in parts by weight: 95.5% of positive electrode active material; 0.8% of granular positive electrode conductive agent; 0.9% of fibrous positive electrode conductive agent; 2.8 percent of positive electrode binder.
Optionally, the positive active material is LiFePO4、LiMnPO4、LiMnxFe1-xPO4、Li3V2(PO4)3At least one of, 0<x<1; and/or the presence of a gas in the atmosphere,
the positive electrode conductive agent comprises a granular positive electrode conductive agent and a fibrous positive electrode conductive agent, the granular positive electrode conductive agent and the fibrous positive electrode conductive agent account for 0.2-7.0% and 0.2-7.0% of the positive electrode coating respectively in parts by weight, the granular positive electrode conductive agent is conductive graphite or conductive carbon black, and the fibrous positive electrode conductive agent is a carbon nano tube or carbon fiber or a combination of the carbon nano tube and graphene; and/or the presence of a gas in the atmosphere,
the positive adhesive is polyvinylidene fluoride or polyvinyl alcohol; and/or the presence of a gas in the atmosphere,
the thickness of the positive electrode metal substrate is 12 microns +/-2 microns, and the thickness of the battery positive electrode sheet is 155 microns +/-5 microns; and/or the presence of a gas in the atmosphere,
the positive metal substrate is an aluminum foil; and/or the presence of a gas in the atmosphere,
the positive coating comprises two positive top coating layers coated on the top surface of the positive metal substrate at intervals and two positive bottom coating layers coated on the bottom surface of the positive metal substrate at intervals, gaps between the positive top coating layers and between the positive bottom coating layers are arranged in an up-down alignment mode, and positive lugs are welded in the gaps of the positive top coating layers.
A second object of the present invention is to provide a method for manufacturing the positive electrode sheet for a battery, including the steps of:
preparing anode slurry, namely mixing the anode binder, the granular conductive agent and the fibrous conductive agent according to the weight part ratio in the anode coating, adding the mixture into a nitrogen-methyl pyrrolidone solvent for mixing to prepare an anode conductive agent glue solution, and adding the anode active substance and the nitrogen-methyl pyrrolidone solvent into the anode conductive agent glue solution to prepare the anode slurry with the solid content of 40-75%;
coating the positive electrode slurry on the positive electrode metal substrate to obtain a positive electrode coating intermediate product;
drying and curing the anode slurry, namely placing the anode coating intermediate product in an environment of 120-150 ℃ for drying and curing so as to dry and cure the anode slurry into the anode coating and prepare an anode cured intermediate product;
a positive plate processing step, namely sequentially rolling and cutting the positive solidified intermediate product to obtain a positive plate semi-finished product;
and a positive tab welding step, namely welding a positive tab on the semi-finished product of the positive plate to obtain the battery positive plate.
Optionally, an embodiment of the cathode slurry coating step is: coating the anode slurry on the top surface and the bottom surface of the anode metal substrate at intervals respectively so as to form two anode top coating layers arranged at intervals on the top surface of the anode metal substrate, forming two anode bottom coating layers arranged at intervals on the bottom surface of the anode metal substrate, wherein a gap between the two anode top coating layers and a gap between the two anode bottom coating layers are arranged in a vertically aligned manner; in the step of welding the positive tab, the positive tab is welded in a gap between two positive top coating layers of the semi-finished positive plate; and/or the presence of a gas in the atmosphere,
in the step of preparing the positive electrode slurry, the solid content of the positive electrode slurry is 47% or 48% or 50%; and/or the presence of a gas in the atmosphere,
the implementation mode of the processing step of the positive plate is as follows: and rolling the positive electrode curing intermediate product into a first sheet with the thickness of 150 +/-5 microns, and cutting the first sheet into strip-shaped sheets with the width of 65 +/-5 mm to obtain the semi-finished positive electrode sheets.
The third purpose of the invention is to provide a lithium ion battery, which comprises a battery shell, a battery negative plate, a first diaphragm, a second diaphragm, electrolyte and the battery positive plate, the battery positive plate, the battery negative plate, the first diaphragm, the second diaphragm and the electrolyte are all arranged in the battery shell, and the battery positive plate, the battery negative plate, the first diaphragm and the second diaphragm are all immersed in the electrolyte, the battery negative plate is positioned between the battery positive plate and the battery shell, the first diaphragm is arranged between the battery positive plate and the battery negative plate, the second diaphragm is arranged between the battery shell and the battery negative plate, the battery negative plate comprises a negative metal substrate and a negative coating coated outside the negative metal substrate, and the negative coating comprises the following components in parts by weight:
86.0 to 97.0 percent of negative active material;
0.2 to 6.0 percent of negative electrode conductive agent;
1.2 to 4.0 percent of suspending agent;
1.4 to 3.4 percent of negative pole binder.
Optionally, the negative electrode coating comprises the following components in parts by weight: 94.8% of negative electrode active material, 1.5% of negative electrode conductive agent, 1.5% of suspending agent and 2.2% of negative electrode binder; or,
the negative coating comprises the following components in parts by weight: 95.2% of negative electrode active material, 1.0% of negative electrode conductive agent, 1.8% of suspending agent and 2.0% of negative electrode binder; or,
the negative coating comprises the following components in parts by weight: 95.4% of negative electrode active material, 0.8% of negative electrode conductive agent, 2.0% of suspending agent and 1.8% of negative electrode binder.
Optionally, the negative active material is at least one of graphite powder and a silicon-based composite material; and/or the presence of a gas in the atmosphere,
the negative conductive agent is conductive carbon black or conductive graphite or carbon nano tubes; and/or the presence of a gas in the atmosphere,
the negative electrode binder is sodium carboxymethylcellulose or styrene butadiene rubber or polyacrylic acid or sodium alginate; and/or the presence of a gas in the atmosphere,
the suspending agent is sodium carboxymethyl cellulose; and/or the presence of a gas in the atmosphere,
the width of the battery negative plate is 66.5mm +/-5 mm and is greater than that of the battery positive plate, and the width of the first diaphragm and the width of the second diaphragm are both greater than that of the battery negative plate and are both 68.5mm +/-5 mm; and/or the presence of a gas in the atmosphere,
the thickness of the negative electrode metal substrate is 8 microns +/-2 microns, and the thickness of the battery negative electrode sheet is 115 microns +/-5 microns; and/or the presence of a gas in the atmosphere,
the negative metal substrate is a copper foil; and/or the presence of a gas in the atmosphere,
the battery shell is cylindrical, the outer diameter of the battery shell is 18.25mm +/-0.35 mm, and the height of the battery shell is 73mm +/-5 mm; and/or the presence of a gas in the atmosphere,
the first diaphragm and the second diaphragm are both polypropylene films or polyethylene films or three-layer composite films of polypropylene films, polyethylene films and polypropylene films.
A fourth object of the present invention is to provide a method for manufacturing the lithium ion battery, including the steps of: respectively preparing the battery shell, the battery positive plate, the battery negative plate, the first diaphragm, the second diaphragm and the electrolyte, and assembling the battery shell, the battery positive plate, the battery negative plate, the first diaphragm, the second diaphragm and the electrolyte, wherein the battery positive plate is prepared by adopting the manufacturing method of the battery positive plate;
the battery negative plate is prepared by the following steps:
a step of preparing cathode slurry, which is to mix the suspending agent with deionized water according to the weight part ratio in the cathode coating to prepare suspending agent glue solution with the solid content of 1.5 +/-0.5%, add the cathode active substance, the cathode conductive agent and the cathode binder according to the weight part ratio in the cathode coating to mix, add deionized water and mix evenly to prepare cathode slurry with the solid content of 45-55%;
coating the negative electrode slurry on the negative electrode metal substrate to dry and solidify the negative electrode slurry into a negative electrode coating to obtain a negative electrode coating intermediate product;
a step of drying and curing the cathode slurry, which is to place the cathode coating intermediate product in an environment of 100-130 ℃ for drying and curing to prepare a cathode curing intermediate product;
a negative plate processing step, namely sequentially rolling and cutting the negative solidified intermediate product to obtain a negative plate semi-finished product;
and a negative electrode tab welding step, wherein a negative electrode tab is welded on the semi-finished product of the negative electrode sheet to prepare the battery negative electrode sheet.
Optionally, the battery case, the battery positive plate, the battery negative plate, the first separator, the second separator, and the electrolyte are assembled in the following manner: stacking the battery positive plate, the battery negative plate, the first diaphragm and the second diaphragm in sequence of the second diaphragm, the battery negative plate, the first diaphragm and the battery positive plate, and then winding into a cylindrical pole group winding core, assembling the cylindrical pole group winding core into the battery shell to manufacture a semi-finished product battery core, and baking the semi-finished product battery core for 24 hours; injecting electrolyte into the semi-finished product battery cell, and then sealing the semi-finished product battery cell to obtain a semi-finished product battery; and (3) infiltrating and activating the semi-finished product battery for 40 hours at the constant temperature of 30-45 ℃ in a manner of first inverted infiltrating and then forward infiltrating, and then charging the semi-finished product battery to form the lithium ion battery.
According to the battery positive plate and the manufacturing method thereof, the lithium ion battery and the manufacturing method thereof, the positive active substance is made of phosphate materials, and the dressing amount of the positive active substance is increased by increasing the width of the battery positive plate; meanwhile, the components of the anode coating on the battery anode plate are optimally designed, so that the capacity of the battery anode plate and the adhesive force of the anode coating on the anode metal substrate are improved, the resistance of the battery anode plate is reduced, the capacity of the finally manufactured lithium ion battery can reach 2000mAh, the capacity of the lithium ion battery is effectively improved, and the lithium ion battery has the advantages of long cycle life, outstanding rate capability and reliable safety performance.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a schematic front view of a positive plate of a battery provided by an embodiment of the invention before a positive tab is welded;
fig. 2 is a schematic top view of a positive plate of a battery provided by an embodiment of the invention before a positive tab is welded;
fig. 3 is a schematic structural diagram of a front view of a battery positive plate provided by an embodiment of the invention after a positive tab is welded;
fig. 4 is a schematic top view of a positive plate of a battery provided by an embodiment of the invention after a positive tab is welded;
fig. 5 is a schematic diagram of an internal structure of a lithium ion battery provided in an embodiment of the present invention;
fig. 6 is a schematic diagram of an external structure of a lithium ion battery according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.
It will also be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
In addition, the descriptions related to "first", "second", etc. in the present invention are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.
As shown in fig. 1 to 6, the width L of the positive electrode sheet 1 of the battery provided by the embodiment of the present invention is 65mm ± 5 mm; the battery positive plate 1 comprises a positive metal substrate 11, a positive lug 13 in conductive connection with the positive metal substrate 11 and a positive coating 12 coated outside the positive metal substrate 11, wherein the positive coating 12 comprises the following components in parts by weight:
88.0% -98.6% of positive active material;
1.0-7.0% of positive electrode binder;
0.4% -14.0% of positive electrode conductive agent;
the positive electrode active material is a phosphate material, and the positive electrode conductive agent comprises at least one of a granular positive electrode conductive agent and a fibrous positive electrode conductive agent.
According to the battery positive plate 1 provided by the embodiment of the invention, the positive active substance is made of phosphate materials, and the dressing amount of the positive active substance is increased by increasing the width L of the battery positive plate 1; meanwhile, the components of the anode coating 12 on the battery anode plate 1 are optimally designed, so that the capacity of the battery anode plate 1 and the adhesive force of the anode coating 12 on the anode metal substrate 11 are improved, the resistance of the battery anode plate 1 is reduced, the capacity of the finally manufactured lithium ion battery can reach 2000mAh, the capacity of the lithium ion battery is effectively improved, and the lithium ion battery has the advantages of long cycle life, outstanding rate capability and reliable safety performance.
Specifically, the battery positive electrode sheet 1 is a rectangular sheet before being wound, and the size of the short side of the rectangular sheet is the width L of the battery positive electrode sheet 1. The battery positive plate 1 is a cylindrical sheet body after being wound, and the height of the cylindrical sheet body is the width L of the battery positive plate 1. The width L of the positive plate 1 of the battery is set within the range of 65mm +/-5 mm in the embodiment, on the one hand, the width of the positive plate 1 of the battery is effectively increased, on the other hand, the height H of the lithium ion battery which is finally manufactured is convenient to control, on the other hand, after the positive plate 1 of the battery and the negative plate 3 of the battery are wound, on the other hand, the negative plate 3 of the battery can completely wrap the positive plate 1 of the battery, and the safety performance of the lithium ion battery is guaranteed.
Preferably, the positive electrode conductive agent comprises a granular positive electrode conductive agent and a fibrous positive electrode conductive agent, and the granular positive electrode conductive agent and the fibrous positive electrode conductive agent account for 0.2-7.0% and 0.2-7.0% of the positive electrode coating respectively in parts by weight. The positive electrode coating 12 of the battery positive electrode plate 1 simultaneously adopts two different conductive agents, namely a granular conductive agent and a fibrous conductive agent, which are matched for use, and the two conductive agents have different particle sizes, specific surface areas, structural states and conductive effects, so that the two conductive agents are combined for mutual reinforcement, and have the effects of increasing one and more than two, thereby being beneficial to reducing the internal resistance of the battery and improving the capacity, cycle performance and rate capability of the battery.
Preferably, the positive electrode coating 12 comprises the following components in parts by weight: 94.8% of positive electrode active material; 1.0% of granular positive electrode conductive agent; 1.2% of fibrous positive electrode conductive agent; 3.0% of positive electrode binder; or, the positive coating 12 comprises the following components in parts by weight: 95.3% of positive electrode active material; 0.9% of granular positive electrode conductive agent; 1.0% of fibrous positive electrode conductive agent; 2.8% of a positive electrode binder; or, the positive coating 12 comprises the following components in parts by weight: 95.5% of positive electrode active material; 0.8% of granular positive electrode conductive agent; 0.9% of fibrous positive electrode conductive agent; 2.8 percent of positive electrode binder. According to test tests, the positive electrode coating 12 adopts the components in parts by weight, and the obtained effects of improving the capacity of the positive electrode plate 1 of the battery, improving the adhesive force of the positive electrode coating 12 on the positive electrode metal substrate 11, improving the cycle performance of the positive electrode plate 1 of the battery and improving the safety performance of the lithium ion battery are obvious.
Preferably, the positive electrode active material is LiFePO4、LiMnPO4、LiMnxFe1-xPO4、Li3V2(PO4)3At least one (any one or any combination) of 0<x<1. The capacity of the battery positive plate 1 is fully ensured by optimally designing the material of the positive active material, so that the capacity, the long cycle life, the rate capability and the safety performance of the finally manufactured lithium ion battery are ensured.
Preferably, the particulate positive electrode conductive agent is conductive graphite or conductive carbon black. The material of the granular positive electrode conductive agent is optimally designed, so that the granular positive electrode conductive agent is favorably matched with the fibrous positive electrode conductive agent, and the internal resistance of the battery is effectively reduced.
More preferably, the granular positive electrode conductive agent is any one of conductive carbon black 350G, SP-Li, acetylene black, Ketjen black, conductive graphite KS-6, conductive graphite KS-15, conductive graphite SFG-6 and conductive graphite SFG-15.
Preferably, the fibrous positive electrode conductive agent is Carbon Nanotubes (CNTs) or carbon fibers (VGCF) or a combination of carbon nanotubes and graphene. The material of the fibrous positive electrode conductive agent is optimally designed, so that the fibrous positive electrode conductive agent is favorably matched with the granular positive electrode conductive agent, and the internal resistance of the battery is effectively reduced.
Preferably, the positive binder is polyvinylidene fluoride (PVDF) or polyvinyl alcohol (PVA), and the two binders are adopted, so that the positive coating 12 and the positive metal substrate 11 can have good adhesive property.
Preferably, the thickness t of the positive electrode metal substrate 11112 μm +/-2 μm, the thickness t of the battery positive plate 12Is 155 mu m +/-5 mu m, thus being beneficial to exerting the best performance of the positive active material on the premise of ensuring the small size of the battery positive plate 1.
Preferably, the positive electrode metal substrate 11 is an aluminum foil, which can meet the conductive performance requirement of the battery positive electrode plate 1, and has light weight and low cost.
Preferably, the positive electrode coating 12 includes two positive electrode top coating layers 121 coated on the top surface of the positive electrode metal substrate 11 at intervals and two positive electrode bottom coating layers 122 coated on the bottom surface of the positive electrode metal substrate 11 at intervals, and a gap between the two positive electrode top coating layers 121 and a gap between the two positive electrode bottom coating layers 122 are aligned vertically, and the positive electrode tab 13 is welded in the gap between the two positive electrode top coating layers 121. Here, by optimally designing the relative positions of the positive electrode metal substrate 11, the positive electrode tab 13 and the positive electrode coating 12, the positive electrode tab 13 is welded in the gap between the two positive electrode top coating layers 121, so that the internal resistance of the finally manufactured lithium ion battery is small, and the circulation is facilitated.
Further, the embodiment of the present invention also provides a method for manufacturing the positive electrode plate 1 of the battery, which includes the following steps:
a positive electrode slurry preparation step, wherein a positive electrode binder, a granular conductive agent and a fibrous conductive agent are mixed according to the weight part ratio in the positive electrode coating 12, and are added into a nitrogen-methyl pyrrolidone (NMP) solvent to be mixed to prepare a positive electrode conductive agent glue solution, and a positive electrode active substance (added according to the weight part ratio in the positive electrode coating 12) and the nitrogen-methyl pyrrolidone solvent are added into the positive electrode conductive agent glue solution to prepare a positive electrode slurry with the solid content of 40-75%;
a positive electrode slurry coating step, namely coating the positive electrode slurry on a positive electrode metal substrate 11 to prepare a positive electrode coating intermediate product;
a step of drying and curing the anode slurry, which is to place the anode coating intermediate product in an environment of 120-150 ℃ for drying and curing so as to dry and cure the anode slurry into an anode coating 12 and prepare an anode curing intermediate product;
a positive plate processing step, namely sequentially rolling and cutting the positive solidified intermediate product to obtain a positive plate semi-finished product;
and a positive tab welding step, namely welding a positive tab 13 on the semi-finished product of the positive tab to obtain the battery positive tab 1.
In the method for manufacturing the battery positive plate 1 provided by the embodiment of the invention, the solvent is nitrogen-methyl pyrrolidone solvent, the solid content of the positive slurry is 40-75%, and the positive slurry is dried and cured into the positive coating 12 in an environment of 120-150 ℃, so that the coating operation of the positive slurry on the positive metal substrate 11 is facilitated, and the drying and curing efficiency of the positive slurry is ensured to be high. The manufacturing method of the battery positive plate 1 provided by the embodiment of the invention has the advantages that the manufacturing process is simple, the production efficiency is high, in the manufactured battery positive plate 1, the capacity of the battery positive plate 1 is high, the adhesive force of the positive coating 12 on the positive metal substrate 11 is strong, the resistance of the battery positive plate 1 is low, and the capacity, the cycle performance and the safety performance of a lithium ion battery are favorably improved.
Preferably, the positive electrode slurry coating step is performed by: the top surface and the bottom surface of the positive electrode metal substrate 11 are coated with positive electrode slurry at intervals respectively, so that two positive electrode top coating layers 121 arranged at intervals are formed on the top surface of the positive electrode metal substrate 11, two positive electrode bottom coating layers 122 arranged at intervals are formed on the bottom surface of the positive electrode metal substrate 11, and a gap between the two positive electrode top coating layers 121 and a gap between the two positive electrode bottom coating layers 122 are arranged in a vertically-aligned manner. By adopting the coating mode, the welding position is reserved for the positive lug 13.
Preferably, in the positive tab welding step, the positive tab 13 is welded in the gap between the two positive top coating layers 121 of the semi-finished positive plate. This is advantageous to ensure that positive tab 13 can make conductive contact with positive metal substrate 11.
Preferably, in the step of preparing the positive electrode slurry, the solid content of the positive electrode slurry is 47% or 48% or 50%, which is beneficial to simultaneously considering the coating performance and the drying and curing efficiency of the positive electrode slurry.
Preferably, the processing step of the positive electrode plate is implemented as follows: rolling the positive electrode curing intermediate product into a first sheet with the thickness of 155 mu m +/-5 mu m, and cutting the first sheet into strip-shaped sheets with the width of 65mm +/-5 mm to obtain a semi-finished positive electrode sheet.
Further, the embodiment of the invention also provides a lithium ion battery, which comprises a battery shell 2, a battery negative plate 3, a first diaphragm 4, a second diaphragm 5, an electrolyte and the battery positive plate 1, wherein the battery positive plate 1, the battery negative plate 3, the first diaphragm 4, the second diaphragm 5 and the electrolyte are all arranged in the battery shell 2, the battery positive plate 1, the battery negative plate 3, the first diaphragm 4 and the second diaphragm 5 are all immersed in the electrolyte, the battery negative plate 3 is positioned between the battery positive plate 1 and the battery shell 2, the first diaphragm 4 is arranged between the battery positive plate 1 and the battery negative plate 3, and the second diaphragm 5 is arranged between the battery shell 2 and the battery negative plate 3. According to the lithium ion battery provided by the embodiment of the invention, the battery positive plate 1 is adopted, so that the capacity, the cycle performance and the safety performance of the lithium ion battery are effectively improved. The anode active substance is a phosphate material, the battery capacity reaches more than 2000mAh, and the lithium ion battery has the characteristics of long cycle life, outstanding rate performance and reliable safety performance, and effectively improves the battery energy of the lithium ion battery.
Preferably, the battery negative electrode sheet 3 comprises a negative electrode metal substrate and a negative electrode coating coated outside the negative electrode metal substrate, wherein the negative electrode coating comprises the following components in parts by weight: 86.0 to 97.0 percent of negative active material; 0.2 to 6.0 percent of negative electrode conductive agent; 1.2 to 4.0 percent of suspending agent; 1.4 to 3.4 percent of negative pole binder. Here, through carrying out the optimal design to the composition of negative pole coating, improved the capacity of battery negative pole piece 3 and the adhesive force of negative pole coating on negative pole metal substrate, reduced the resistance of battery negative pole piece 3, and then do benefit to further promotion lithium ion battery's capacity, cycle performance and security performance. In addition, the setting of the suspending agent can ensure that the cathode conductive agent and the cathode active substance are well dispersed and in a suspended state in the prepared cathode slurry, ensure the stability of the subsequent processing process (coating process) of the cathode slurry, avoid the agglomeration of the cathode conductive agent and avoid the sedimentation of the cathode active substance.
Preferably, the negative electrode coating comprises the following components in parts by weight: 94.8% of negative electrode active material, 1.5% of negative electrode conductive agent, 1.5% of suspending agent and 2.2% of negative electrode binder; or the negative coating comprises the following components in parts by weight: 95.2% of negative electrode active material, 1.0% of negative electrode conductive agent, 1.8% of suspending agent and 2.0% of negative electrode binder; or the negative coating comprises the following components in parts by weight: 95.4% of negative electrode active material, 0.8% of negative electrode conductive agent, 2.0% of suspending agent and 1.8% of negative electrode binder. Test tests show that the negative electrode coating adopts the components in parts by weight, and the effects of improving the capacity of the battery negative electrode sheet 3, improving the adhesive force of the negative electrode coating on a negative electrode metal substrate and reducing the resistance of the battery negative electrode sheet 3 are obvious.
Preferably, the negative active material is at least one of graphite powder and a silicon-based composite material. The graphite powder can be natural graphite powder or artificial stone ink powder. Here, by optimally designing the material of the negative electrode active material, the capacity of the battery negative electrode sheet 3 is sufficiently ensured.
Preferably, the negative electrode conductive agent is conductive carbon black or conductive graphite or carbon nanotubes. Here, the material of the negative electrode conductive agent is optimally designed, which is beneficial to reducing the internal resistance of the battery.
More preferably, the negative electrode conductive agent is any one of conductive carbon black 350G, SP-Li, conductive graphite KS-6, conductive graphite SFG-6, Ketjen black ECP-600JD and carbon nanotube CNT.
Preferably, the negative electrode binder is sodium carboxymethylcellulose (CMC), Styrene Butadiene Rubber (SBR), polyacrylic acid (PAA), or sodium alginate. The material of the cathode binder is optimally designed, so that the cathode coating and the cathode metal substrate are favorably ensured to have good bonding performance.
Preferably, the suspending agent is sodium carboxymethylcellulose (CMC). The suspending agent is sodium carboxymethylcellulose, so that the cathode conductive agent and the cathode active substance can be suspended in the prepared cathode slurry, and meanwhile, the adhesive force between components of the cathode coating and the adhesive force between the cathode coating and the cathode metal substrate after the battery cathode sheet 3 is dried can be improved by utilizing the adhesive capacity of the sodium carboxymethylcellulose and the synergistic effect of the cathode adhesive.
Preferably, the width of the negative electrode sheet 3 is 66.5mm ± 5mm, the width of the negative electrode sheet 3 is greater than the width of the positive electrode sheet 3, and the width of the first separation film 4 and the width of the second separation film 5 are both greater than the width of the negative electrode sheet 3 and are both 68.5mm ± 5 mm. Because the width of the positive plate 1 of the battery is 65mm +/-5 mm, therefore, the width of the negative plate 3 of the battery, the width of the first diaphragm 4 and the width of the second diaphragm 5 are optimally designed, the positive plate 1 of the battery and the negative plate 3 of the battery are favorably ensured to be wound, the negative plate 3 of the battery can completely wrap the positive plate 1 of the battery, the diaphragm can completely separate the positive plate 1 of the battery and the negative plate 3 of the battery, the diaphragm can completely wrap the negative plate 3 of the battery, and the safety performance of the lithium ion battery is fully ensured.
Preferably, the thickness of the negative electrode metal substrate is 8 μm ± 2 μm, and the thickness of the battery negative electrode sheet 3 is 115 μm ± 5 μm, so that the best performance of the negative electrode active material can be exerted on the premise of ensuring the size of the battery negative electrode sheet 3 to be smaller.
Preferably, the negative electrode metal substrate is a copper foil, which has good conductivity and can meet the conductivity requirement of the battery negative electrode sheet 3.
Preferably, the negative electrode coating comprises a negative electrode top coating layer coated on the top surface of the negative electrode metal substrate and a negative electrode bottom coating layer coated on the bottom surface of the negative electrode metal substrate, and the negative electrode tab is welded on the top surface of the negative electrode metal substrate and located beside the negative electrode top coating layer. Therefore, when the battery is packaged, the negative pole lug is welded at the bottom of the nickel-plated steel shell.
Preferably, the coating area of the negative electrode top coating layer on the surface of the negative electrode metal substrate is larger than that of the negative electrode bottom coating layer on the surface of the negative electrode metal substrate. Here, leave big clearance at negative pole metal substrate bottom surface and not coat, because in the battery assembling process, the back is convoluteed to the battery negative pole piece, and the non-coating district of negative pole metal substrate bottom surface is at the outer lane of book core, and it is nickel plating steel shell, does not have positive electrode material to counterpoint with it, like this, under the prerequisite of guaranteeing the battery performance, does benefit to reduce cost.
Preferably, the negative electrode metal substrate is a rectangular sheet body, the negative electrode metal substrate has two long outer edges opposite to each other at intervals and two short outer edges opposite to each other at intervals, the negative electrode tab is welded on the top surface of the negative electrode metal substrate near one short outer edge, the negative electrode top coating layer extends to the side of the negative electrode tab from the other short outer edge of the negative electrode metal substrate, one end of the negative electrode bottom coating layer and the end of the negative electrode top coating layer near the negative electrode tab are in up-down positive alignment, and the other end of the negative electrode bottom coating layer and the end of the negative electrode top coating layer far away from the negative electrode tab have. The positions of the negative electrode metal substrate, the negative electrode coating and the negative electrode lug are optimally designed, so that the using amount of the negative electrode coating can be reduced, and the performance of the finally manufactured lithium ion battery can be ensured.
Preferably, the battery case 2 has a cylindrical shape, the outer diameter d of the battery case 2 is 18.25mm + -0.35 mm, and the height H of the battery case 2 is 73mm + -5 mm. Here, by optimally designing the shape of the battery case 2, it is advantageous to save packaging (Pack) cost, improve packaging efficiency, and make the battery Pack that packages the battery smaller and lighter.
Preferably, the first membrane 4 and the second membrane 5 are both a polypropylene film or a polyethylene film or a three-layer composite film of polypropylene, polyethylene and polypropylene having micropores.
As a preferred embodiment of this embodiment, the lithium ion battery is cylindrical, the outer diameter d of the lithium ion battery is 18.25 ± 0.35mm, and the height H of the lithium ion battery is 73.0 ± 5.0mm, so that the beneficial effects that the weight energy density and the volume energy density of the battery are both increased by 11% to 16% compared with the 18650 type lithium ion battery are achieved, and the lithium ion battery can be applied to the market fields of digital code, power, energy storage and the like instead of the 18650 type lithium ion battery.
According to the lithium ion battery provided by the embodiment of the invention, the components of the coatings on the battery positive plate 1 and the battery negative plate 3 are changed, and the widths of the battery positive plate 1 and the battery negative plate 3 are increased, so that the dressing amount of active substances is increased, and the battery capacity is increased; the widths of the first diaphragm 4 and the second diaphragm 5 are increased, the battery positive plate 1 and the battery negative plate 3 are completely separated, and the battery negative plate 3 is completely wrapped, so that the safety performance of the lithium ion battery is guaranteed; in addition, the injection amount of the electrolyte of the lithium ion battery is increased, and the electrolyte amount is ensured to be enough to infiltrate the battery positive plate 1, the battery negative plate 3, the first diaphragm 4 and the second diaphragm 5.
Further, an embodiment of the present invention further provides a manufacturing method of the lithium ion battery, including the following steps: respectively preparing a battery shell 2, a battery positive plate 1, a battery negative plate 3, a first diaphragm 4, a second diaphragm 5 and electrolyte, assembling the battery shell 2, the battery positive plate 1, the battery negative plate 3, the first diaphragm 4, the second diaphragm 5 and the electrolyte, and preparing the battery positive plate 1 by adopting the manufacturing method of the battery positive plate 1. In the embodiment of the invention, the battery positive plate 1 is prepared by adopting the manufacturing method of the battery positive plate 1, so that the manufacturing process of the lithium ion battery is effectively optimized, and the capacity, the cycle performance and the safety performance of the lithium ion battery are improved.
Preferably, the battery negative electrode sheet 3 is prepared by the following steps:
a step of preparing cathode slurry, which is to mix a suspending agent with deionized water according to the weight part ratio in a cathode coating to prepare a suspending agent glue solution with the solid content of 1.5 +/-0.5%, add a cathode active substance, a cathode conductive agent and a cathode binder according to the weight part ratio in the cathode coating to mix, add deionized water and mix uniformly to prepare cathode slurry with the solid content of 45-55%;
coating the negative electrode slurry on a negative electrode metal substrate to obtain a negative electrode coating intermediate product;
a step of drying and curing the cathode slurry, which is to place the cathode coating intermediate product in an environment of 100-130 ℃ for drying and curing to prepare a cathode curing intermediate product;
a negative plate processing step, namely sequentially rolling and cutting the negative solidified intermediate product to obtain a negative plate semi-finished product;
and a negative electrode tab welding step, namely welding a negative electrode tab 31 on the semi-finished product of the negative electrode sheet to obtain the battery negative electrode sheet 3.
In the method for manufacturing the battery negative plate 3 provided by the embodiment of the invention, the solvent adopts deionized water, the solid content of the negative slurry is set to be 45-55%, and the negative slurry is dried and cured into the negative coating in the environment of 100-130 ℃, so that the coating operation of the negative slurry on the negative metal substrate is facilitated, and the drying and curing efficiency of the negative slurry is ensured to be higher. The manufacturing method of the battery negative plate 3 provided by the embodiment of the invention has the advantages that the manufacturing process is simple, the production efficiency is high, the capacity of the battery negative plate 3 is high in the manufactured battery negative plate 3, the adhesive force of the negative coating on the negative metal substrate is strong, the resistance of the battery negative plate 3 is low, and the capacity, the cycle performance and the safety performance of the lithium ion battery are favorably improved.
Preferably, the anode slurry coating step is implemented as: and coating the cathode slurry on the top surface and the bottom surface of the cathode metal substrate at intervals respectively to form at least two cathode top coating layers arranged at intervals on the top surface of the cathode metal substrate and at least two cathode bottom coating layers arranged at intervals on the bottom surface of the cathode metal substrate. By adopting the coating mode, the welding position is reserved for the negative electrode tab 31.
Preferably, in the negative electrode tab welding step, the negative electrode tabs 31 are welded in the gap between the two negative electrode top coating layers of the semi-finished negative electrode sheet. This is beneficial to ensure that the negative tab 31 can make conductive contact with the negative metal substrate.
Preferably, in the step of preparing the negative electrode slurry, the solid content of the negative electrode slurry is 50% or 48% or 49%, which is beneficial to simultaneously considering the coating performance and the drying and curing efficiency of the negative electrode slurry.
Preferably, the negative electrode sheet processing step is implemented as follows: rolling the cathode solidified intermediate product into a second sheet with the thickness of 130 mu m +/-5 mu m, and cutting the second sheet into a strip sheet with the width of 66.5mm +/-5 mm to obtain a semi-finished product of the anode sheet.
Preferably, the battery case 2, the battery positive plate 1, the battery negative plate 3, the first separator 4, the second separator 5 and the electrolyte are assembled in the following manner: stacking a battery positive plate 1, a battery negative plate 3, a first diaphragm 4 and a second diaphragm 5 in sequence of the second diaphragm 5, the battery negative plate 3, the first diaphragm 4 and the battery positive plate 1, then winding the stacked plates into a cylindrical pole group winding core, assembling the cylindrical pole group winding core in a battery shell 2 to prepare a semi-finished product battery core, and baking the semi-finished product battery core for 24 hours; injecting electrolyte into the semi-finished product battery cell, and then sealing the semi-finished product battery cell to obtain a semi-finished product battery; and (3) infiltrating and activating the semi-finished product battery for 40 hours in a manner of first inverted infiltrating and then forward infiltrating at the constant temperature of 30-45 ℃, and then charging the semi-finished product battery to form the lithium ion battery. The assembly process of the lithium ion battery is optimally designed, so that the comprehensive performance of the lithium ion battery is effectively improved. Specifically, the moisture content of the finally prepared battery cell is reduced by increasing the baking time of the semi-finished battery cell to 24 hours; the activation and infiltration time of the battery is increased to 40h, so that the diaphragm, the battery positive plate 1 and the battery negative plate 3 can be fully infiltrated by the electrolyte; meanwhile, the activation infiltration mode of the battery is improved, and the battery is firstly immersed in an inverted mode and then immersed in a forward mode under the constant temperature condition of 30-45 ℃, so that the infiltration effect is effectively improved.
Preferably, the battery case 2 includes a nickel-plated steel can 21 and a cap 22. The concrete implementation mode that the cylindrical pole group winding core is assembled in the battery shell 2 to form a semi-finished product battery core is as follows: the cylindrical pole assembly winding core is arranged in the nickel-plated steel shell 21, the negative pole lug 31 is spot-welded at the bottom of the nickel-plated steel shell 21, and then the roll groove is formed according to design parameters; and welding the positive lug 13 at the position of the bus bar sheet of the cap 22 by laser welding to obtain a semi-finished product battery core.
In the aspect of nickel plating steel casing 21 design, because battery positive plate 1, battery negative plate 3, the width of first diaphragm 4 and second diaphragm 5 all increases, the cylindric utmost point group roll core height after the coiling increases, therefore, the height of corresponding increase nickel plating steel casing 21, thereby the inner chamber volume of nickel plating steel casing 21 has been improved, the lower edge cavity after having ensured nickel plating steel casing 21 roll slot can hold cylindric utmost point group roll core completely, improve nickel plating steel casing 21's processability simultaneously, guarantee nickel plating steel casing 21 is at the stability of course of working.
The test result of the lithium ion battery provided by the embodiment of the invention is as follows: the charging and discharging limit voltage of the lithium ion battery is 3.65V-2.00V, when the lithium ion battery is subjected to constant current and constant voltage charging (the cut-off current is 0.01CA) with the current of 0.2CA until the voltage is 3.65V, and then the lithium ion battery is discharged with the constant current of 0.2CA until the voltage is 2.00V, the discharging capacity of the lithium ion battery is not lower than the nominal capacity; when the charge-discharge cycle test is carried out on the lithium ion battery by a 0.5CA constant-current constant-voltage charge and 0.5CA constant-current discharge system, the capacity retention rate of the lithium ion battery in the 1000 th week is more than or equal to 78.5 percent; when the charge-discharge cycle test is carried out on the lithium ion battery by a 0.5CA constant-current constant-voltage charge and 1.0CA constant-current discharge system, the capacity retention rate of the lithium ion battery in the 800 th week is more than or equal to 78.5 percent.
The following describes the manufacturing method and test procedure of the lithium ion battery by three preferred embodiments:
example 1:
preparation of the battery negative electrode sheet 3: 1.5 wt% of suspending agent CMC dry powder and deionized water are mixed to prepare suspending agent glue solution with the solid content of 1.5%, 94.8 wt% of graphite powder, 1.5 wt% of conductive graphite and 2.2 wt% of SBR are added to be mixed, and then deionized water is added to be mixed uniformly to prepare cathode slurry with the solid content of 50%. Coating the negative electrode slurry on a metal copper foil with the thickness of 8 mu m in a clearance manner, drying at the temperature of 100-130 ℃, and rolling into a second sheet body with the thickness of about 111 mu m, wherein the second sheet body is designed to have the compaction density of not higher than 1.7g/cm3And cutting the plate body into a strip shape, wherein the width of the cut plate body is 66.5mm, and welding negative electrode lugs 31 at the gap foil to manufacture the battery negative electrode plate 3.
Preparation of the battery positive plate 1: firstly, 3.0 wt% of binder PVDF dry powder, 1.0 wt% of conductive agent Ks-6 and 1.2 wt% of carbon nano tube oily slurry are mixed, a proper amount of solvent nitrogen-methyl pyrrolidone (NMP) is added for mixing to prepare conductive agent glue solution, 94.8 wt% of positive electrode active material lithium iron phosphate and a proper amount of NMP are added for mixing to prepare positive electrode slurry with 47% of solid content. Coating the positive electrode slurry on a metal aluminum foil with the thickness of 12 mu m in a clearance way, drying the metal aluminum foil at the temperature of 120-150 ℃, and rolling the metal aluminum foil into a first sheet body with the thickness of about 156 mu m, wherein the first sheet body is designed to have the compaction density of not higher than 2.7g/cm3And cutting the first sheet into a strip shape, wherein the width of the cut sheet is 65mm, and welding the positive tab 13 at the gap foil to manufacture the battery positive plate 1.
Assembling the lithium ion battery: the battery positive plate 1, the battery negative plate 3, the first diaphragm 4 and the second diaphragm 5 are stacked in sequence according to the second diaphragm 5, the battery negative plate 3, the first diaphragm 4 and the battery positive plate 1 and then wound into a cylindrical pole group winding core, and the width of the used diaphragm (comprising the first diaphragm 4 and the second diaphragm 5) is 68.5 mm. Sleeving the cylindrical pole group winding core into the nickel-plated steel shell 21, spot-welding the negative pole lug 31 at the bottom of the nickel-plated steel shell 21, and performing roll grooving according to design parameters; and welding the positive lug 13 at the junction of the cap 22 by laser welding to obtain a semi-finished cell. Baking the semi-finished product battery cell, injecting 6.5g of electrolyte, and sealing according to the designed sealing parameters to obtain a semi-finished product battery; activating the semi-finished product battery to enable the electrolyte to fully soak the anode material, the cathode material and the diaphragm; and charging the semi-finished product battery according to a formation process to form the lithium ion battery.
Testing of the lithium ion battery: the charging and discharging limit voltage of the lithium ion battery is 3.65V-2.0V, when the lithium ion is subjected to constant-current constant-voltage charging (the cut-off current is 0.01CA) with the current of 0.2CA until the voltage is 3.65V, and then the lithium ion battery is discharged with the constant current of 0.2CA until the voltage is 2.0V, the discharge capacity of the battery is more than or equal to 2000 mAh; when a charge-discharge cycle test is carried out on the lithium ion battery by a 0.5CA constant-current constant-voltage charge and 0.5CA constant-current discharge system, the capacity retention rate of the battery at the 1000 th week is more than or equal to 78.5 percent; when the battery is subjected to charge-discharge cycle test by a 0.5CA constant-current constant-voltage charge and 1.0CA constant-current discharge system, the capacity retention rate of the battery at the 800 th week is more than or equal to 78.5%.
Example 2:
preparation of the battery negative electrode sheet 3: 1.8 wt% of suspending agent CMC dry powder and deionized water are mixed to prepare suspending agent glue solution with solid content of 1.5%, 95.2 wt% of graphite powder, 1.0 wt% of conductive graphite and 2.0 wt% of SBR are added to be mixed, deionized water is added to be mixed uniformly, and negative pole slurry with solid content of 48% is prepared. Coating the negative electrode slurry on a metal copper foil with the thickness of 8 mu m in a clearance way, drying the metal copper foil at the temperature of 100-130 ℃, and rolling the metal copper foil into a second sheet body with the thickness of about 115 mu m, wherein the second sheet body is designed to have the compaction density of not higher than 1.7g/cm3. Cutting the second sheet into stripAnd the width of the cut sheet body is 66.5mm, and the negative electrode tab 31 is welded at the gap foil material to manufacture the battery negative electrode sheet 3.
Preparation of the battery positive plate 1: firstly, 2.8 wt% of binder PVDF dry powder, 0.9 wt% of conductive agent Ks-6 and 1.0 wt% of carbon nano tube oily slurry are mixed, a proper amount of solvent nitrogen-methyl pyrrolidone (NMP) is added for mixing to prepare conductive agent glue solution, 95.3 wt% of positive electrode active material lithium iron phosphate and a proper amount of NMP are added for mixing to prepare positive electrode slurry with 50% of solid content. Coating the positive electrode slurry on a metal aluminum foil with the thickness of 12 mu m in a clearance way, drying the metal aluminum foil at the temperature of 120-150 ℃, and rolling the metal aluminum foil into a first sheet body with the thickness of about 153 mu m, wherein the first sheet body is designed to have the compaction density of not higher than 2.7g/cm3. And cutting the first sheet into a strip shape, wherein the width of the cut sheet is 65mm, and welding the positive tab 13 at the gap foil to manufacture the battery positive plate 1.
Assembling the lithium ion battery: the assembly is the same as in embodiment 1 and will not be described in detail.
Testing of the lithium ion battery: the test method is the same as that of example 1, and is not described in detail here. And (3) testing results: the battery discharge capacity is more than or equal to 2050 mAh; when a charge-discharge cycle test is carried out on the lithium ion battery by a 0.5CA constant-current constant-voltage charge and 0.5CA constant-current discharge system, the capacity retention rate of the battery at the 1000 th week is more than or equal to 80.5 percent; when the battery is subjected to charge-discharge cycle test by a 0.5CA constant-current constant-voltage charge and 1.0CA constant-current discharge system, the capacity retention rate of the battery at the 800 th week is more than or equal to 80.0%.
Example 3:
preparation of the battery negative electrode sheet 3: firstly, mixing 2.0 wt% of suspending agent CMC dry powder with deionized water to prepare a suspending agent glue solution with a solid content of 1.5%, adding 95.4 wt% of graphite powder, 0.8 wt% of conductive graphite and 1.8 wt% of SBR, mixing, adding deionized water, and uniformly mixing to prepare a negative electrode slurry with a solid content of 49%. The negative electrode paste was gap-coated to a thickness of 8 μmDrying the metal copper foil at the temperature of 100-130 ℃, and rolling the metal copper foil into a second sheet body with the thickness of about 116 mu m, wherein the second sheet body is designed to have the compaction density of not higher than 1.7g/cm3. And cutting the second sheet body into a strip shape, wherein the width of the cut sheet body is 66.5mm, and welding negative electrode lugs 31 at the gap foil to manufacture the battery negative electrode sheet 3.
Preparation of the battery positive plate 1: firstly, 2.8 wt% of binder PVDF dry powder, 0.8 wt% of conductive agent Ks-6 and 0.9 wt% of carbon nano tube oily slurry are mixed, a proper amount of solvent nitrogen-methyl pyrrolidone (NMP) is added for mixing to prepare conductive agent glue solution, 95.5 wt% of active material lithium iron phosphate and a proper amount of NMP are added for mixing to prepare anode slurry with 48% of solid content. Coating the positive electrode slurry on a metal aluminum foil with the thickness of 12 mu m in a clearance way, drying the metal aluminum foil at the temperature of 120-150 ℃, and rolling the metal aluminum foil into a first sheet body with the thickness of about 158 mu m, wherein the first sheet body is designed to have the compaction density of not higher than 2.7g/cm3. And cutting the first sheet into a strip shape, wherein the width of the cut sheet is 65mm, and welding the positive tab 13 at the gap foil to manufacture the battery positive plate 1.
Assembling the lithium ion battery: the assembly is the same as in embodiment 1 and will not be described in detail.
Testing of the lithium ion battery: the test method is the same as that of example 1, and is not described in detail here. And (3) testing results: the battery discharge capacity is more than or equal to 2080 mAh; when a charge-discharge cycle test is carried out on the lithium ion battery by a 0.5CA constant-current constant-voltage charge and 0.5CA constant-current discharge system, the capacity retention rate of the battery at the 1000 th week is more than or equal to 81.5 percent; when the battery is subjected to charge-discharge cycle test by a 0.5CA constant-current constant-voltage charge and 1.0CA constant-current discharge system, the capacity retention rate of the battery at the 800 th week is more than or equal to 80.8%.
Comparative example:
preparing a battery negative plate: mixing 2.2 wt% of suspending agent CMC dry powder with deionized water to prepare suspending agent glue solution with solid content of 1.8%, adding 93.2 wt% of graphite powder, 2.2 wt% of conductive graphite and 2.4 wt% of SBR, mixing, and adding into the mixtureAdding deionized water, and mixing uniformly to prepare the cathode slurry with the solid content of 42%. Coating the negative electrode slurry on a metal copper foil with the thickness of 8 mu m in a clearance way, drying at the temperature of 100-130 ℃, and rolling into a sheet body with the thickness of about 101 mu m, wherein the designed compaction density of the sheet body is not higher than 1.6g/cm3And cutting the sheet body into a strip shape, wherein the width of the cut sheet body is 57.5mm, and welding negative electrode lugs at the gap foil to manufacture the battery negative electrode sheet.
Preparing a battery positive plate: firstly, 3.5 wt% of binder PVDF dry powder, 1.2 wt% of conductive agent Ks-6 and 1.3 wt% of carbon nano tube oily slurry are mixed, a proper amount of solvent nitrogen-methyl pyrrolidone (NMP) is added for mixing to prepare conductive agent glue solution, and 94.0 wt% of active material lithium iron phosphate and a proper amount of NMP are added for mixing to prepare positive electrode slurry with the solid content of 43%. The positive electrode slurry was gap-coated on a 14 μm thick metal aluminum foil, dried at a temperature of 120 ℃ and 150 ℃, and then rolled into a sheet having a thickness of about 166 μm and designed to have a compaction density of not more than 2.5g/cm3And cutting the sheet into long strips, wherein the width of the cut sheet is 55.5mm, and welding positive lugs at the gap foil to manufacture the battery positive plate.
Assembling the lithium ion battery: the positive plate, the negative plate and the diaphragm of the battery are overlapped according to the sequence of 'diaphragm/negative plate/diaphragm/positive plate' and then wound into a cylindrical pole group, and the diaphragm is a polyethylene film with the width of 60.5mm and the thickness of 16 mu m. Sleeving the nickel-plated steel shell, spot-welding the negative electrode lug at the bottom of the steel shell, and rolling a groove; and welding the positive lug at the position of the cap bus sheet by laser welding to prepare a semi-finished product battery cell. After baking the semi-finished product battery cell, injecting 5.8g of electrolyte, and sealing; activating to make the electrolyte fully infiltrate the anode material, the cathode material and the diaphragm; after the battery is charged and formed, the 18650-1600mAh battery is assembled.
Testing of the battery: the charging and discharging limit voltage of the battery is 3.65V-2.0V, when the constant-current constant-voltage charging (the cut-off current is 0.01CA) is carried out on the battery by the current of 0.2CA until the voltage is 3.65V, and then the constant current of 0.2CA is used for discharging the battery until the voltage is 2.0V, the discharging capacity of the battery is 1650 mAh; when the battery is subjected to charge-discharge cycle test by a 0.5CA constant-current constant-voltage charge and 0.5CA constant-current discharge system, the capacity retention rate of the battery is 78.2% in the 1000 th week; when the battery is subjected to charge-discharge cycle test by a 0.5CA constant-current constant-voltage charge and 1.0CA constant-current discharge system, the capacity retention rate of the battery is 78.4% in the 800 th week.
The test results are compared with the following table 1:
TABLE 1
Table 1 shows the test results in comparative example (18650 type lithium ion battery), example 1, example 2, and example 3. As can be seen from table 1, the lithium ion batteries provided in embodiments 1, 2, and 3 of the present invention have improved battery capacity and all reach 2000mAh compared to the conventional 18650 model lithium ion battery. In addition, the battery energy is improved by 21-26% compared with a 18650 lithium ion battery. The capacity retention ratio of the battery at the 1000 th week and the capacity retention ratio of the battery at the 800 th week are both greater than or equal to 78.5%.
The lithium ion battery provided by the embodiment of the invention can be applied to the market fields of digital codes, power, energy storage and the like, wherein the positive active material is made of a lithium iron phosphate material, and the width of the battery positive plate 1 and the proportion of the positive active material, the positive binder, the granular positive conductive agent and the fibrous positive conductive agent in the positive coating 12 are adjusted, so that the battery capacity reaches 2000mAh, the rate capability is outstanding, and the safety performance is reliable.
Compared with the existing 18650-type lithium ion battery, the lithium ion battery provided by the embodiment of the invention has the following beneficial effects:
1) the energy is higher. The battery capacity reaches 2000mAh, and the highest capacity of a 18650 type lithium ion battery is 1650 mAh; the energy of the single lithium ion battery provided by the embodiment of the invention is improved by 21-26% compared with the 18650 lithium ion battery.
2) The manufacturing cost of the battery is reduced. Compared with 18650 type lithium ion batteries, the lithium ion battery provided by the embodiment of the invention has no difference in manufacturing process, equipment depreciation and labor cost, but has higher energy, and the cost is calculated according to watt hour, so that the lithium ion battery provided by the embodiment of the invention has obviously more advantages.
3) The lithium ion battery provided by the embodiment of the invention has the advantages of long battery cycle life, stable discharge voltage platform, outstanding rate capability and reliable safety performance.
4) The packaging efficiency is improved, and the packaging cost is saved. Because the energy density of the lithium ion battery provided by the embodiment of the invention is higher than that of a 18650 type lithium ion battery, the number of the used lithium ion batteries is reduced by 19% in the downstream packaging process of the lithium ion battery on the premise of the same energy output, so that the packaging production efficiency is improved, and the equipment depreciation cost and the packaging labor cost are further saved.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (10)
1. The battery positive plate is characterized in that the width of the battery positive plate is 65mm +/-5 mm; the battery positive plate comprises a positive metal substrate, a positive lug in conductive connection with the positive metal substrate and a positive coating coated outside the positive metal substrate, wherein the positive coating comprises the following components in parts by weight:
88.0% -98.6% of positive active material;
1.0-7.0% of positive electrode binder;
0.4% -14.0% of positive electrode conductive agent;
the positive electrode active substance is a phosphate material, and the positive electrode conductive agent comprises at least one of a granular positive electrode conductive agent and a fibrous positive electrode conductive agent.
2. The positive plate of the battery according to claim 1, wherein the positive coating comprises the following components in parts by weight: 94.8% of positive electrode active material; 1.0% of granular positive electrode conductive agent; 1.2% of fibrous positive electrode conductive agent; 3.0% of positive electrode binder; or,
the anode coating comprises the following components in parts by weight: 95.3% of positive electrode active material; 0.9% of granular positive electrode conductive agent; 1.0% of fibrous positive electrode conductive agent; 2.8% of a positive electrode binder; or,
the anode coating comprises the following components in parts by weight: 95.5% of positive electrode active material; 0.8% of granular positive electrode conductive agent; 0.9% of fibrous positive electrode conductive agent; 2.8 percent of positive electrode binder.
3. The positive electrode sheet according to claim 1 or 2, wherein the positive active material is LiFePO4、LiMnPO4、LiMnxFe1-xPO4、Li3V2(PO4)3At least one of, 0<x<1; and/or the presence of a gas in the atmosphere,
the positive electrode conductive agent comprises a granular positive electrode conductive agent and a fibrous positive electrode conductive agent, the granular positive electrode conductive agent and the fibrous positive electrode conductive agent account for 0.2-7.0% and 0.2-7.0% of the positive electrode coating respectively in parts by weight, the granular positive electrode conductive agent is conductive graphite or conductive carbon black, and the fibrous positive electrode conductive agent is a carbon nano tube or carbon fiber or a combination of the carbon nano tube and graphene; and/or the presence of a gas in the atmosphere,
the positive adhesive is polyvinylidene fluoride or polyvinyl alcohol; and/or the presence of a gas in the atmosphere,
the thickness of the positive electrode metal substrate is 12 microns +/-2 microns, and the thickness of the battery positive electrode sheet is 155 microns +/-5 microns; and/or the presence of a gas in the atmosphere,
the positive metal substrate is an aluminum foil; and/or the presence of a gas in the atmosphere,
the positive coating comprises two positive top coating layers coated on the top surface of the positive metal substrate at intervals and two positive bottom coating layers coated on the bottom surface of the positive metal substrate at intervals, gaps between the positive top coating layers and between the positive bottom coating layers are arranged in an up-down alignment mode, and positive lugs are welded in the gaps of the positive top coating layers.
4. The method for manufacturing a positive electrode sheet for a battery according to any one of claims 1 to 3, comprising the steps of:
preparing anode slurry, namely mixing the anode binder, the granular conductive agent and the fibrous conductive agent according to the weight part ratio in the anode coating, adding the mixture into a nitrogen-methyl pyrrolidone solvent for mixing to prepare an anode conductive agent glue solution, and adding the anode active substance and the nitrogen-methyl pyrrolidone solvent into the anode conductive agent glue solution to prepare the anode slurry with the solid content of 40-75%;
coating the positive electrode slurry on the positive electrode metal substrate to obtain a positive electrode coating intermediate product;
drying and curing the anode slurry, namely placing the anode coating intermediate product in an environment of 120-150 ℃ for drying and curing so as to dry and cure the anode slurry into the anode coating and prepare an anode cured intermediate product;
a positive plate processing step, namely sequentially rolling and cutting the positive solidified intermediate product to obtain a positive plate semi-finished product;
and a positive tab welding step, namely welding a positive tab on the semi-finished product of the positive plate to obtain the battery positive plate.
5. The method for manufacturing a positive electrode sheet for a battery according to claim 4, wherein the positive electrode slurry coating step is carried out in a manner that: coating the anode slurry on the top surface and the bottom surface of the anode metal substrate at intervals respectively so as to form two anode top coating layers arranged at intervals on the top surface of the anode metal substrate, forming two anode bottom coating layers arranged at intervals on the bottom surface of the anode metal substrate, wherein a gap between the two anode top coating layers and a gap between the two anode bottom coating layers are arranged in a vertically aligned manner; in the step of welding the positive tab, the positive tab is welded in a gap between two positive top coating layers of the semi-finished positive plate; and/or the presence of a gas in the atmosphere,
in the step of preparing the positive electrode slurry, the solid content of the positive electrode slurry is 47% or 48% or 50%; and/or the presence of a gas in the atmosphere,
the implementation mode of the processing step of the positive plate is as follows: and rolling the positive electrode curing intermediate product into a first sheet with the thickness of 150 +/-5 microns, and cutting the first sheet into strip-shaped sheets with the width of 65 +/-5 mm to obtain the semi-finished positive electrode sheets.
6. The lithium ion battery is characterized by comprising a battery shell, a battery negative plate, a first diaphragm, a second diaphragm, electrolyte and the battery positive plate as claimed in any one of claims 1 to 3, wherein the battery positive plate, the battery negative plate, the first diaphragm, the second diaphragm and the electrolyte are all arranged in the battery shell, the battery positive plate, the battery negative plate, the first diaphragm and the second diaphragm are all immersed in the electrolyte, the battery negative plate is positioned between the battery positive plate and the battery shell, the first diaphragm is arranged between the battery positive plate and the battery negative plate, the second diaphragm is arranged between the battery shell and the battery negative plate, the battery negative plate comprises a negative metal substrate and a negative coating coated outside the negative metal substrate, the negative coating comprises the following components in parts by weight:
86.0 to 97.0 percent of negative active material;
0.2 to 6.0 percent of negative electrode conductive agent;
1.2 to 4.0 percent of suspending agent;
1.4 to 3.4 percent of negative pole binder.
7. The lithium ion battery of claim 6, wherein the negative electrode coating comprises the following components in parts by weight: 94.8% of negative electrode active material, 1.5% of negative electrode conductive agent, 1.5% of suspending agent and 2.2% of negative electrode binder; or,
the negative coating comprises the following components in parts by weight: 95.2% of negative electrode active material, 1.0% of negative electrode conductive agent, 1.8% of suspending agent and 2.0% of negative electrode binder; or,
the negative coating comprises the following components in parts by weight: 95.4% of negative electrode active material, 0.8% of negative electrode conductive agent, 2.0% of suspending agent and 1.8% of negative electrode binder.
8. The lithium ion battery of claim 7, wherein the negative active material is at least one of graphite powder and a silicon-based composite material; and/or the presence of a gas in the atmosphere,
the negative conductive agent is conductive carbon black or conductive graphite or carbon nano tubes; and/or the presence of a gas in the atmosphere,
the negative electrode binder is sodium carboxymethylcellulose or styrene butadiene rubber or polyacrylic acid or sodium alginate; and/or the presence of a gas in the atmosphere,
the suspending agent is sodium carboxymethyl cellulose; and/or the presence of a gas in the atmosphere,
the width of the battery negative plate is 66.5mm +/-5 mm and is greater than that of the battery positive plate, and the width of the first diaphragm and the width of the second diaphragm are both greater than that of the battery negative plate and are both 68.5mm +/-5 mm; and/or the presence of a gas in the atmosphere,
the thickness of the negative electrode metal substrate is 8 microns +/-2 microns, and the thickness of the battery negative electrode sheet is 115 microns +/-5 microns; and/or the presence of a gas in the atmosphere,
the negative metal substrate is a copper foil; and/or the presence of a gas in the atmosphere,
the battery shell is cylindrical, the outer diameter of the battery shell is 18.25mm +/-0.35 mm, and the height of the battery shell is 73mm +/-5 mm; and/or the presence of a gas in the atmosphere,
the first diaphragm and the second diaphragm are both polypropylene films or polyethylene films or three-layer composite films of polypropylene films, polyethylene films and polypropylene films.
9. The method of manufacturing a lithium ion battery according to any of claims 6 to 8, comprising the steps of: preparing the battery case, the battery positive plate, the battery negative plate, the first diaphragm, the second diaphragm and the electrolyte respectively, and assembling the battery case, the battery positive plate, the battery negative plate, the first diaphragm, the second diaphragm and the electrolyte, wherein the battery positive plate is prepared by the method for manufacturing the battery positive plate according to claim 4 or 5;
the battery negative plate is prepared by the following steps:
a step of preparing cathode slurry, which is to mix the suspending agent with deionized water according to the weight part ratio in the cathode coating to prepare suspending agent glue solution with the solid content of 1.5 +/-0.5%, add the cathode active substance, the cathode conductive agent and the cathode binder according to the weight part ratio in the cathode coating to mix, add deionized water and mix evenly to prepare cathode slurry with the solid content of 45-55%;
coating the negative electrode slurry on the negative electrode metal substrate to dry and solidify the negative electrode slurry into a negative electrode coating to obtain a negative electrode coating intermediate product;
a step of drying and curing the cathode slurry, which is to place the cathode coating intermediate product in an environment of 100-130 ℃ for drying and curing to prepare a cathode curing intermediate product;
a negative plate processing step, namely sequentially rolling and cutting the negative solidified intermediate product to obtain a negative plate semi-finished product;
and a negative electrode tab welding step, wherein a negative electrode tab is welded on the semi-finished product of the negative electrode sheet to prepare the battery negative electrode sheet.
10. The method of manufacturing a lithium ion battery according to claim 9, wherein the battery case, the battery positive electrode sheet, the battery negative electrode sheet, the first separator, the second separator, and the electrolyte solution are assembled in such a manner that: stacking the battery positive plate, the battery negative plate, the first diaphragm and the second diaphragm in sequence of the second diaphragm, the battery negative plate, the first diaphragm and the battery positive plate, and then winding into a cylindrical pole group winding core, assembling the cylindrical pole group winding core into the battery shell to manufacture a semi-finished product battery core, and baking the semi-finished product battery core for 24 hours; injecting electrolyte into the semi-finished product battery cell, and then sealing the semi-finished product battery cell to obtain a semi-finished product battery; and (3) infiltrating and activating the semi-finished product battery for 40 hours at the constant temperature of 30-45 ℃ in a manner of first inverted infiltrating and then forward infiltrating, and then charging the semi-finished product battery to form the lithium ion battery.
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