CN112331905A - High-safety lithium ion battery and preparation method thereof - Google Patents
High-safety lithium ion battery and preparation method thereof Download PDFInfo
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- CN112331905A CN112331905A CN202011290864.3A CN202011290864A CN112331905A CN 112331905 A CN112331905 A CN 112331905A CN 202011290864 A CN202011290864 A CN 202011290864A CN 112331905 A CN112331905 A CN 112331905A
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- glue layer
- tab glue
- tab
- lithium ion
- ion battery
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 38
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 38
- 238000002360 preparation method Methods 0.000 title description 9
- 239000003292 glue Substances 0.000 claims abstract description 158
- 238000002844 melting Methods 0.000 claims abstract description 38
- 230000008018 melting Effects 0.000 claims abstract description 38
- 238000003466 welding Methods 0.000 claims abstract description 34
- 239000004020 conductor Substances 0.000 claims abstract description 19
- 239000010410 layer Substances 0.000 claims description 99
- -1 polypropylene Polymers 0.000 claims description 19
- 239000004743 Polypropylene Substances 0.000 claims description 18
- 229920001155 polypropylene Polymers 0.000 claims description 18
- 239000011347 resin Substances 0.000 claims description 18
- 229920005989 resin Polymers 0.000 claims description 18
- 239000000463 material Substances 0.000 claims description 8
- 150000001875 compounds Chemical class 0.000 claims description 7
- 239000002131 composite material Substances 0.000 claims description 6
- 239000012790 adhesive layer Substances 0.000 claims description 4
- 229920001911 maleic anhydride grafted polypropylene Polymers 0.000 claims description 4
- 239000000853 adhesive Substances 0.000 claims description 3
- 230000001070 adhesive effect Effects 0.000 claims description 3
- 238000012360 testing method Methods 0.000 abstract description 16
- 238000000034 method Methods 0.000 abstract description 15
- 229910052751 metal Inorganic materials 0.000 abstract description 13
- 239000002184 metal Substances 0.000 abstract description 13
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 239000000126 substance Substances 0.000 abstract description 3
- 230000008569 process Effects 0.000 abstract description 2
- 239000011248 coating agent Substances 0.000 description 11
- 238000000576 coating method Methods 0.000 description 11
- 230000000052 comparative effect Effects 0.000 description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 239000011230 binding agent Substances 0.000 description 5
- 239000006258 conductive agent Substances 0.000 description 5
- 239000011267 electrode slurry Substances 0.000 description 5
- 238000004806 packaging method and process Methods 0.000 description 5
- 238000007789 sealing Methods 0.000 description 5
- 239000002002 slurry Substances 0.000 description 5
- 239000002033 PVDF binder Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 238000002347 injection Methods 0.000 description 4
- 239000007924 injection Substances 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 238000002156 mixing Methods 0.000 description 4
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 4
- 238000003756 stirring Methods 0.000 description 4
- 230000032683 aging Effects 0.000 description 3
- 239000001768 carboxy methyl cellulose Substances 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
- 229910002804 graphite Inorganic materials 0.000 description 3
- 239000010439 graphite Substances 0.000 description 3
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 3
- 239000007773 negative electrode material Substances 0.000 description 3
- 239000007774 positive electrode material Substances 0.000 description 3
- 238000004804 winding Methods 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910021383 artificial graphite Inorganic materials 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000007772 electrode material Substances 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 239000002985 plastic film Substances 0.000 description 2
- 229920006255 plastic film Polymers 0.000 description 2
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 2
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 description 2
- 238000009757 thermoplastic moulding Methods 0.000 description 2
- 239000002562 thickening agent Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910001148 Al-Li alloy Inorganic materials 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- 229910008365 Li-Sn Inorganic materials 0.000 description 1
- 229910008410 Li-Sn-O Inorganic materials 0.000 description 1
- 229910012820 LiCoO Inorganic materials 0.000 description 1
- 229910006759 Li—Sn Inorganic materials 0.000 description 1
- 229910006763 Li—Sn—O Inorganic materials 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N SnO2 Inorganic materials O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910010248 TiO2—Li4Ti5O12 Inorganic materials 0.000 description 1
- PFYQFCKUASLJLL-UHFFFAOYSA-N [Co].[Ni].[Li] Chemical compound [Co].[Ni].[Li] PFYQFCKUASLJLL-UHFFFAOYSA-N 0.000 description 1
- HFCVPDYCRZVZDF-UHFFFAOYSA-N [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O Chemical compound [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O HFCVPDYCRZVZDF-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 229910003481 amorphous carbon Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 125000002573 ethenylidene group Chemical group [*]=C=C([H])[H] 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 238000007731 hot pressing Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- 239000002931 mesocarbon microbead Substances 0.000 description 1
- 239000000203 mixture Substances 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
- 238000011056 performance test Methods 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000002153 silicon-carbon composite material Substances 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
- H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
-
- 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
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Secondary Cells (AREA)
Abstract
The invention provides a high-safety lithium ion battery. The lithium ion battery comprises a pole piece and a pole lug, wherein the pole lug comprises a metal conductor, the first end of the metal conductor is a welding end, the second end, opposite to the first end, of the metal conductor is a probing end, the welding end and a pole lug glue area formed between the probing ends are arranged on the pole lug glue area, and the melting point of the pole lug glue layer is less than or equal to 150 ℃. The lithium ion battery has the following advantages: the method is simple in process and high in compatibility with the existing mass production process. The method improves furnace temperature safety and simultaneously has no loss of electrical property. The invention uses the low-melting-point tab glue to replace the conventional tab glue, and can improve the temperature of the battery boosting test furnace of the high-voltage quick-charging system on the premise of not changing a chemical system. The method has the characteristics of simplicity, strong practicability and mass production.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a method for improving the safety of a high-voltage quick-charging system of a lithium ion battery, a high-safety lithium ion battery and a preparation method thereof.
Background
Since the commercialization of lithium ion batteries, lithium ion batteries have been widely used as power sources for various mobile devices due to their characteristics of high energy density, high power density, good cycle performance, no memory effect, environmental friendliness, and the like. With the large-scale application of lithium ion batteries, the safety problem of the batteries is increasingly prominent.
In the prior art, the thermal stability of the negative electrode is worse and worse along with the gradual increase of the charging rate of the battery, and the boost charging can further deteriorate the thermal stability of the negative electrode on the original basis, which indicates that the lithium ion battery has potential safety hazard in the furnace temperature experiment. Therefore, the safety of the lithium ion battery in the prior art is low.
Disclosure of Invention
At present, the furnace temperature (Hotbox) test of the high-voltage quick-charging system battery is one of tests which are difficult to pass, which seriously affects the safety performance of the lithium ion battery, and the main reasons are that the amorphous carbon coating amount in the negative plate of the high-voltage quick-charging system battery is large, so that the thermal stability of graphite is reduced, and each large mobile phone client requires the furnace temperature test to be boosted, so that the thermal stability of the negative plate of the high-voltage quick-charging system battery is further reduced.
Based on the phenomenon, how to improve the furnace temperature passing rate of the high-voltage quick-charging system battery is urgently needed to be solved on the premise of ensuring that the electrical property of the battery is not lost, and the problem of the furnace temperature passing rate of the high-voltage quick-charging system battery can be well solved by using the low-melting-point tab glue to replace the conventional tab glue, so that the safety performance of the lithium ion battery is improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a lithium ion battery, lithium ion battery includes pole piece and utmost point ear, utmost point ear includes metallic conductor, metallic conductor's first end is the welding end, metallic conductor's the second end relative with first end is for exploring the end, the welding end with it glues the region to form utmost point ear between the end to visit set up utmost point ear glue film on the utmost point ear glue region, the melting point of utmost point ear glue film is less than or equal to 150 ℃, preferably less than or equal to 140 ℃, if less than or equal to 130 ℃.
According to the invention, the welding end is one end for welding the tab to the pole piece, in particular one end for welding the metal conductor to the current collector of the pole piece, and the welding end and the pole piece are welded to form a welding area.
According to the invention, the tab glue area is provided with a first tab glue layer and a second tab glue layer, the first tab glue layer is arranged on the surface of the tab glue area, the second tab glue layer is arranged on the surface of the first tab glue layer, namely the first tab glue layer and the second tab glue layer are sequentially connected and arranged on the surface of the tab glue area, the melting point of the first tab glue layer is not more than 130 ℃, and the melting point of the second tab glue layer is not less than 130 ℃.
According to the invention, the tab glue area is provided with a first tab glue layer, a second tab glue layer and a third tab glue layer, the first tab glue layer is arranged on the surface of the tab glue area, the second tab glue layer is arranged on the surface of the first tab glue layer, the third tab glue layer is arranged on the surface of the second tab glue layer, namely the first tab glue layer, the second tab glue layer and the third tab glue layer are sequentially arranged on the surface of the tab glue area in a connection manner, the melting point of the first tab glue layer and the melting point of the third tab glue layer are less than or equal to 130 ℃, and the melting point of the second tab glue layer is greater than or equal to 130 ℃.
According to the invention, the melting point of the first tab glue layer is 100-130 ℃, such as 100 ℃, 110 ℃, 120 ℃ or 130 ℃.
According to the invention, the melting point of the second aureola layer is 130-160 ℃, such as 130 ℃, 140 ℃, 150 ℃ or 160 ℃.
According to the invention, the melting point of the third auricle glue layer is 100-130 ℃, such as 100 ℃, 110 ℃, 120 ℃ or 130 ℃.
According to the invention, the melting point of the second tab glue layer is greater than the melting point of the first tab glue layer.
According to the invention, the melting point of the second tab adhesive layer is greater than the melting point of the third tab adhesive layer.
According to the invention, the melting point of the first tab glue layer and the melting point of the third tab glue layer are the same or different, preferably the same.
According to the invention, the material of the tab glue forming the first tab glue layer is selected from a compound of polypropylene and modified resin, and the compound refers to a composite material formed by thermoplastic molding of the polypropylene and the modified resin.
According to the invention, the material of the tab glue forming the third tab glue layer is selected from a compound of polypropylene and modified resin, and the compound refers to a composite material formed by thermoplastic molding of polypropylene and modified resin.
The tab glue forming the first tab glue layer may be the same as or different from the tab glue forming the third tab glue layer, and is preferably the same.
Wherein the melting point of the polypropylene is 130-160 ℃.
Wherein the modified resin is selected from polypropylene resin or maleic anhydride grafted polypropylene resin with different melting point from the polypropylene.
Among them, the maleic anhydride-grafted polypropylene resin is, for example, commercially available as QE840 material produced by mitsui chemical company, japan.
Wherein the polypropylene resin is, for example, commercially available, such as from alatin.
Wherein, in the compound, the mass ratio of the polypropylene to the modified resin is 1: 1-40: 1, preferably 1-10: 1, such as 5: 1. By adjusting the mass ratio of the polypropylene to the modified resin, the tab glue with different melting points can be obtained.
According to the invention, the material of the tab adhesive forming the second tab adhesive layer is selected from polypropylene, and the melting point of the tab adhesive is 130-160 ℃.
According to the invention, the welding tension between the welding end of the tab and the pole piece, i.e. the welding tension in the welding area, is greater than 25N.
According to the invention, the thickness of the first tab glue layer is 50-80 μm, such as 50 μm, 60 μm, 70 μm or 80 μm.
According to the invention, the thickness of the second ear glue layer is 50-80 μm, such as 50 μm, 60 μm, 70 μm or 80 μm.
According to the invention, the thickness of the third ear gum layer is 50-80 μm, such as 50 μm, 60 μm, 70 μm or 80 μm.
According to the invention, the size of the tab is not specifically defined, and is suitable for a pole piece, and exemplarily, the width of the tab is 4-10mm, the thickness of the tab is 0.06-0.12mm, for example, the size of the tab is 6mm × 0.08mm, 6mm × 0.1mm, and preferably 6mm × 0.08 mm.
In the invention, by using the low-melting-point tab glue, the low-melting-point tab glue is fused along with the rise of temperature during furnace temperature test, so that heat is released; and conventional tab glue can not be fused, so that heat can be accumulated in the battery, internal chain type side reaction can be continuously performed, thermal runaway is finally triggered, and the test cannot pass. In addition, the tab glue adopting the structure does not have adverse effect on the electrical property of the battery.
The invention also provides a preparation method of the lithium ion battery, which comprises the following steps:
(a) preparing a positive plate and a negative plate;
(b) respectively welding lugs on a prepared positive plate and a prepared negative plate, wherein the lugs comprise metal conductors, the first ends of the metal conductors are welding ends, the second ends of the metal conductors, which are opposite to the first ends, are probing ends, lug glue areas are formed between the welding ends and the probing ends, lug glue layers are arranged in the lug glue areas, and the melting points of the lug glue layers are less than or equal to 150 ℃, preferably less than or equal to 140 ℃, and if less than or equal to 130 ℃;
(c) and (3) manufacturing the positive plate and the negative plate welded with the tabs, the diaphragm and the packaging shell into a battery, and then performing the working procedures of liquid injection, aging, formation, pre-circulation and the like to prepare the lithium ion battery.
According to the invention, the method comprises the following steps:
(1) mixing the positive active material, the conductive agent and the binder according to a certain proportion, adding N-methyl pyrrolidone, stirring and dispersing to prepare positive slurry. Coating the positive electrode slurry on a positive electrode current collector by coating equipment (double-sided coating), drying, cutting, and preparing a sheet to obtain a positive electrode sheet;
(2) mixing the negative active material, the conductive agent, the binder and the thickening agent according to a certain proportion, adding deionized water, stirring and dispersing to prepare negative slurry. Then coating the negative electrode slurry on a negative electrode current collector (double-sided coating), drying, slitting and preparing a sheet to obtain a negative electrode sheet;
(3) welding tabs on the prepared positive pole piece and the prepared negative pole piece, wherein the tabs comprise metal conductors, the first ends of the metal conductors are welding ends, the second ends of the metal conductors, which are opposite to the first ends, are probing ends, tab glue areas are formed between the welding ends and the probing ends, tab glue layers are arranged in the tab glue areas, and the melting points of the tab glue layers are less than or equal to 150 ℃, preferably less than or equal to 140 ℃, and if less than or equal to 130 ℃;
(4) and (3) preparing the positive plate and the negative plate prepared in the third step, a diaphragm and a packaging shell into a battery, then performing the working procedures of liquid injection, aging, formation, pre-circulation and the like, and finally testing the electrochemical performance of the battery.
According to the invention, in the step (b) and the step (3), the tab glue layer is arranged in the tab glue area in the following way:
the first step is as follows: extruding, melting and plasticizing the tab glue (or the material for preparing the tab glue);
the second step is that: filtering the plasticized melt on a 300-mesh screen;
the third step: and casting the filtered melt in an extruder, and cooling to form a tab glue layer.
According to the invention, the positive active material comprises one or more of lithium cobaltate, lithium manganate, lithium iron phosphate, lithium nickel cobalt manganate and lithium nickel cobalt aluminate.
According to the present invention, the negative active material includes natural graphite, artificial graphite, mesocarbon microbeads, hard carbon, soft carbon, silicon, a silicon-carbon composite, a Li-Sn alloy, a Li-Sn-O alloy, Sn, SnO2Spinel-structured lithiated TiO2-Li4Ti5O12And a combination of one or more of Li-Al alloy.
According to the invention, the conductive agent is one or more of point conductive graphite, ultrafine graphite, acetylene black, conductive carbon black SP, superconducting carbon black, carbon nano tubes and conductive carbon fibers.
According to the invention, the binder is selected from at least one of polyvinylidene fluoride, polytetrafluoroethylene, sodium carboxymethylcellulose, styrene-butadiene rubber, polyurethane, polyvinyl alcohol, polyvinylidene fluoride and copolymers of vinylidene fluoride-fluorinated olefins.
According to the invention, the pole piece structure can be a single layer, a double layer or a multilayer, and the pole piece structure is not limited in the application.
According to the invention, the lithium ion battery also comprises a negative plate, electrolyte, a diaphragm and a packaging shell.
The invention also provides a method for improving the safety of the high-voltage quick-charging system of the lithium ion battery, which comprises the step of using the lithium ion battery.
Wherein, the tab glue and the packaging shell are packaged together through hot pressing. Preferably, the packaging shell is made of an aluminum plastic film.
The invention has the beneficial effects that:
the invention provides a high-safety lithium ion battery. The lithium ion battery has the following advantages:
(1) the method is simple in process and high in compatibility with the existing mass production process.
(2) The method improves furnace temperature safety and simultaneously has no loss of electrical property.
(3) The invention uses the low-melting-point tab glue to replace the conventional tab glue, and can improve the temperature of the battery boosting test furnace of the high-voltage quick-charging system on the premise of not changing a chemical system. The method has the characteristics of simplicity, strong practicability and mass production.
Drawings
Fig. 1 is a graph showing cycle performance of the lithium ion batteries of example 1 and comparative example 1.
Fig. 2 is a structural schematic diagram of a tab glue layer in the prior art.
Fig. 3 is a schematic structural view of a tab glue layer according to the present invention.
Fig. 4 is a schematic structural view of a tab of the present invention.
Fig. 5 is a schematic structural diagram of a pole piece of a welding tab of the present invention.
Description of the drawings: 1 is first utmost point ear glue film, 2 is second utmost point ear glue film, and 3 is third utmost point ear glue film, and 4 are utmost point ear glue region, and 5 are third utmost point ear glue film, and 6 are second utmost point ear glue film, and 7 are first utmost point ear glue film, and 8 are the welding end, and 9 are for exploring the end, and 10 are the pole piece.
Detailed Description
The present invention will be described in further detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.
Example 1
(1) Preparation of positive plate
Mixing the positive active material, the conductive agent and the binder in proportion, adding N-methyl pyrrolidone, stirring and dispersing to prepare positive slurry. In the positive electrode slurry, the solid component contained 97.8 wt% of lithium cobaltate (LiCoO)2) 1.1% by weight of conductive carbon black and 1.1% by weight of polyvinylidene fluoride (PVDF).
And coating the positive slurry on a positive current collector by coating equipment (double-sided coating), drying, cutting, and tabletting to obtain the positive plate.
(2) Preparation of negative plate
Mixing the negative active material, the conductive agent, the binder and the thickening agent in proportion, adding deionized water, stirring and dispersing to prepare negative slurry. In the negative electrode slurry, solid components comprise 96.9 wt% of artificial graphite, 0.5 wt% of conductive carbon black, 1.3 wt% of sodium carboxymethyl cellulose (CMC) and 1.3 wt% of Styrene Butadiene Rubber (SBR), and then the negative electrode slurry is coated on a negative electrode current collector (double-sided coating), and the negative electrode sheet is prepared by drying, slitting and sheet-making.
(3) Preparation of tab
Welding a tab on the prepared positive plate and the prepared negative plate, wherein the tab comprises a metal conductor, the first end of the metal conductor is a welding end 8, the second end of the metal conductor, which is opposite to the first end, is a probing end 9, a tab glue area 4 is formed between the welding end 8 and the probing end 9, the welding end 8 and the plate are welded to form a welding area, and the welding tension for measuring the welding area is 28N.
As shown in fig. 3, tab glue area 4 on the surface of both sides of the pole piece is respectively provided with a first tab glue layer 1 and 7, a second tab glue layer 1 and 6, and a third tab glue layer 3 and 5, the first tab glue layer is provided on the surface of tab glue area 4, the second tab glue layer is provided on the surface of first tab glue layer, the third tab glue layer is provided on the surface of second tab glue layer, and the first tab glue layer and the melting point of the third tab glue layer are 120 ℃, the melting point of the second tab glue layer is 160 ℃.
The tab glue layers forming the first tab glue layer and the third tab glue layer are made of a composite (composite material formed by a thermoplastic method) of polypropylene and maleic anhydride grafted polypropylene resin in a mass ratio of 5:1, and the melting point of the composite is 120 ℃. The tab glue forming the second tab glue layer is made of polypropylene with a melting point of 160 ℃.
(4) Preparation of the Battery
Winding the positive plate, the negative plate and the diaphragm to form a winding core, then placing the winding core into an aluminum plastic film to be packaged into a battery, then carrying out the working procedures of liquid injection, aging, formation, sorting and the like, and finally testing the electrochemical performance and the safety performance of the battery.
(5) Furnace temperature testing
Firstly, charging the battery to an upper limit voltage of +30mV (0.02C cutoff) at 0.2C, and testing the initial state of the battery, including voltage, internal resistance, thickness and the like; then the battery is put into an oven and heated at the initial temperature of 25 plus or minus 3 ℃, the temperature rise rate is 5 plus or minus 2 ℃, the temperature rises to 130 plus or minus 2 ℃, and the test is finished after the temperature is kept for 60 min. And (3) judging standard: the battery does not catch fire or smoke.
(6) Cycle testing
The battery is discharged to the lower limit voltage at 0.7C and charged to the upper limit voltage at 2C in a constant temperature room at 25 ℃, and the capacity retention rate of the battery is calculated after the cycle is carried out for 800 weeks.
The preparation environment temperature of the electrode material is kept at 20-30 ℃, and the humidity is less than or equal to 40% RH.
The equipment used for preparing the electrode material comprises: the device comprises a stirrer, a coating machine, a roller press, a splitting machine, a pelleter, an ultrasonic spot welding machine, a top side sealing machine, an ink-jet printer, a film sticking machine, a liquid injection machine, a formation cabinet, a cold press, a separation cabinet, a vacuum oven and the like.
Examples 2 to 4
Examples 2 to 4 differ from example 1 in the composition and melting point of the first tab glue layer and the third tab glue layer, as shown in table 1.
Example 5
Example 5 differs from example 1 in that the welding tension is different.
The welding tension is regulated by the power output of the tensile machine and data can be read on the instrument.
Example 6
Example 6 is different from example 1 in the thickness after the heat sealing of the tab paste.
And the thickness of the tab glue after heat sealing is adjusted through heat sealing temperature.
Comparative example 1
Comparative example 1 differs from example 1 in that the arrangement of the first and third tab glue layers is not included, i.e. only the second tab glue layer is included.
Table 1 parameters of tab glue layers of the batteries of examples 1-6 and comparative example 1
Table 2 parameters of tab glue layers of batteries of examples 1 to 6 and comparative example 1 and performance test parameters of batteries
The results in table 1 show that the furnace temperature test of comparative example 1 has a low pass rate, i.e., low safety, and cannot meet the safety performance requirements of the lithium ion battery. The furnace temperature experiment passing rates of the embodiments 1-6 of the invention are all higher than that of the comparative example 1, so that the safety of the lithium ion battery is effectively improved. Because the furnace temperature pass rate of the embodiment 1 is more excellent, the embodiment 1 can be selected in practical application; in example 5, the tab falls off due to too small welding tension, and the test cannot be carried out; compared with the example 1, the example 6 has the advantages that the tab glue is thick after heat sealing, so that the tab glue cannot be fused in time in an oven temperature test, and the passing rate is reduced within a certain range.
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The utility model provides a lithium ion battery, lithium ion battery includes pole piece and utmost point ear, utmost point ear includes metallic conductor, metallic conductor's first end is the welding end, metallic conductor's the second relative with first end is held for exploring the end, the welding end with it glues the region to form utmost point ear between the end to visit set up utmost point ear glue film on the utmost point ear glue region, the melting point of utmost point ear glue film is less than or equal to 150 ℃.
2. The lithium ion battery of claim 1, wherein the tab glue area is provided with a first tab glue layer and a second tab glue layer, the first tab glue layer is provided on the surface of the tab glue area, the second tab glue layer is provided on the surface of the first tab glue layer, namely the first tab glue layer and the second tab glue layer are sequentially provided on the surface of the tab glue area, and the melting point of the first tab glue layer is 130 ℃ or less, and the melting point of the second tab glue layer is 130 ℃ or more.
3. The lithium ion battery of claim 2, wherein the tab glue area is provided with a first tab glue layer, a second tab glue layer and a third tab glue layer, the first tab glue layer is provided on the surface of the tab glue area, the second tab glue layer is provided on the surface of the first tab glue layer, the third tab glue layer is provided on the surface of the second tab glue layer, namely, the first tab glue layer, the second tab glue layer and the third tab glue layer are sequentially provided on the surface of the tab glue area, and the melting points of the first tab glue layer and the third tab glue layer are 130 ℃ or less, and the melting point of the second tab glue layer is 130 ℃ or more.
4. The lithium ion battery as claimed in claim 2 or 3, wherein the melting point of the first tab glue layer is 100-.
5. The lithium ion battery of claim 3 or 4, wherein the melting point of the third auricle glue layer is 100-130 ℃, and the melting point of the second auricle glue layer is greater than the melting point of the third auricle glue layer.
6. The lithium ion battery according to any one of claims 2 to 5, wherein the tab adhesive forming the first tab adhesive layer is made of a material selected from the group consisting of a composite of polypropylene and a modified resin; and/or the presence of a gas in the gas,
the material of the tab glue forming the third tab glue layer is selected from a compound of polypropylene and modified resin.
7. The lithium ion battery of claim 6, wherein the modified resin is selected from a polypropylene resin or a maleic anhydride grafted polypropylene resin; and/or the presence of a gas in the gas,
in the compound, the mass ratio of the polypropylene to the modified resin is 1: 1-40: 1.
8. The lithium ion battery as claimed in any one of claims 2-7, wherein the tab glue forming the second tab glue layer is made of polypropylene with a melting point of 130-160 ℃.
9. The lithium ion battery according to any one of claims 2-8, wherein the first tab glue layer has a thickness of 50-80 μm, the second tab glue layer has a thickness of 50-80 μm, and the third tab glue layer has a thickness of 50-80 μm.
10. The lithium ion battery of any of claims 2-9, wherein the tab has a width of 4-10mm and a thickness of 0.06-0.12 mm.
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| CN113193233A (en) * | 2021-06-07 | 2021-07-30 | 珠海冠宇电池股份有限公司 | Lithium ion battery |
| CN113285180A (en) * | 2021-05-14 | 2021-08-20 | 格远电子科技（上海）有限公司 | High-temperature-ineffectible tab glue and manufacturing method thereof |
| CN113285181A (en) * | 2021-05-14 | 2021-08-20 | 格远电子科技（上海）有限公司 | High-temperature-ineffectible tab and manufacturing method thereof |
| CN113410510A (en) * | 2021-06-07 | 2021-09-17 | 珠海冠宇电池股份有限公司 | Lithium ion battery |
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