CN113113679A - Structure and method for supplementing lithium to lithium ion battery based on lithium silicide composite material - Google Patents
Structure and method for supplementing lithium to lithium ion battery based on lithium silicide composite material Download PDFInfo
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- CN113113679A CN113113679A CN202110369096.9A CN202110369096A CN113113679A CN 113113679 A CN113113679 A CN 113113679A CN 202110369096 A CN202110369096 A CN 202110369096A CN 113113679 A CN113113679 A CN 113113679A
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- lithium
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- silicide
- pole piece
- composite material
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- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 281
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 275
- 229910021332 silicide Inorganic materials 0.000 title claims abstract description 169
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 title claims abstract description 169
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 108
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 108
- 239000002131 composite material Substances 0.000 title claims abstract description 90
- 238000000034 method Methods 0.000 title claims abstract description 51
- 230000001502 supplementing effect Effects 0.000 title claims abstract description 20
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 64
- 239000013589 supplement Substances 0.000 claims abstract description 37
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 32
- 239000003792 electrolyte Substances 0.000 claims abstract description 21
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 38
- 239000000203 mixture Substances 0.000 claims description 22
- -1 polyethylene Polymers 0.000 claims description 21
- 229910052799 carbon Inorganic materials 0.000 claims description 19
- 239000010410 layer Substances 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 16
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 15
- 230000015572 biosynthetic process Effects 0.000 claims description 15
- 239000006229 carbon black Substances 0.000 claims description 14
- 239000011248 coating agent Substances 0.000 claims description 14
- 238000000576 coating method Methods 0.000 claims description 14
- 239000007769 metal material Substances 0.000 claims description 14
- 239000003575 carbonaceous material Substances 0.000 claims description 12
- 239000002033 PVDF binder Substances 0.000 claims description 11
- 239000004698 Polyethylene Substances 0.000 claims description 10
- 239000004743 Polypropylene Substances 0.000 claims description 10
- 239000000919 ceramic Substances 0.000 claims description 10
- 229920000573 polyethylene Polymers 0.000 claims description 10
- 229920001155 polypropylene Polymers 0.000 claims description 10
- 238000003756 stirring Methods 0.000 claims description 10
- 238000003466 welding Methods 0.000 claims description 10
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- 239000010439 graphite Substances 0.000 claims description 9
- 238000005096 rolling process Methods 0.000 claims description 9
- 238000005520 cutting process Methods 0.000 claims description 8
- 238000004804 winding Methods 0.000 claims description 8
- 239000002002 slurry Substances 0.000 claims description 7
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 6
- 229910052755 nonmetal Inorganic materials 0.000 claims description 6
- 239000000047 product Substances 0.000 claims description 6
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 5
- 239000004917 carbon fiber Substances 0.000 claims description 5
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 5
- 239000002041 carbon nanotube Substances 0.000 claims description 5
- 229910052802 copper Inorganic materials 0.000 claims description 5
- 239000010949 copper Substances 0.000 claims description 5
- 239000004744 fabric Substances 0.000 claims description 5
- 229910021389 graphene Inorganic materials 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 5
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 5
- 239000010935 stainless steel Substances 0.000 claims description 5
- 229910001220 stainless steel Inorganic materials 0.000 claims description 5
- 238000001125 extrusion Methods 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 3
- 239000011268 mixed slurry Substances 0.000 claims description 3
- 238000007789 sealing Methods 0.000 claims description 3
- 239000011265 semifinished product Substances 0.000 claims description 3
- 239000002356 single layer Substances 0.000 claims description 3
- 230000002427 irreversible effect Effects 0.000 abstract description 7
- 230000002441 reversible effect Effects 0.000 abstract description 7
- 230000007613 environmental effect Effects 0.000 abstract description 4
- 238000011031 large-scale manufacturing process Methods 0.000 abstract description 4
- 239000011889 copper foil Substances 0.000 description 10
- 229910052751 metal Inorganic materials 0.000 description 10
- 239000002184 metal Substances 0.000 description 10
- 229910014913 LixSi Inorganic materials 0.000 description 8
- 239000003570 air Substances 0.000 description 8
- 238000007599 discharging Methods 0.000 description 8
- 239000007773 negative electrode material Substances 0.000 description 8
- 210000004027 cell Anatomy 0.000 description 6
- 238000005516 engineering process Methods 0.000 description 4
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 4
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 description 4
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 4
- QHGNHLZPVBIIPX-UHFFFAOYSA-N tin(ii) oxide Chemical compound [Sn]=O QHGNHLZPVBIIPX-UHFFFAOYSA-N 0.000 description 4
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910021383 artificial graphite Inorganic materials 0.000 description 3
- 238000003475 lamination Methods 0.000 description 3
- BDKWOJYFHXPPPT-UHFFFAOYSA-N lithium dioxido(dioxo)manganese nickel(2+) Chemical compound [Mn](=O)(=O)([O-])[O-].[Ni+2].[Li+] BDKWOJYFHXPPPT-UHFFFAOYSA-N 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910021583 Cobalt(III) fluoride Inorganic materials 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 229910021571 Manganese(III) fluoride Inorganic materials 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 238000004026 adhesive bonding Methods 0.000 description 2
- 239000012080 ambient air Substances 0.000 description 2
- WZJQNLGQTOCWDS-UHFFFAOYSA-K cobalt(iii) fluoride Chemical compound F[Co](F)F WZJQNLGQTOCWDS-UHFFFAOYSA-K 0.000 description 2
- 239000011530 conductive current collector Substances 0.000 description 2
- 210000001787 dendrite Anatomy 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 229910021385 hard carbon Inorganic materials 0.000 description 2
- SHXXPRJOPFJRHA-UHFFFAOYSA-K iron(iii) fluoride Chemical compound F[Fe](F)F SHXXPRJOPFJRHA-UHFFFAOYSA-K 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 229910052960 marcasite Inorganic materials 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- YQCIWBXEVYWRCW-UHFFFAOYSA-N methane;sulfane Chemical compound C.S YQCIWBXEVYWRCW-UHFFFAOYSA-N 0.000 description 2
- 229910021382 natural graphite Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- NIFIFKQPDTWWGU-UHFFFAOYSA-N pyrite Chemical compound [Fe+2].[S-][S-] NIFIFKQPDTWWGU-UHFFFAOYSA-N 0.000 description 2
- 229910052683 pyrite Inorganic materials 0.000 description 2
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 239000002153 silicon-carbon composite material Substances 0.000 description 2
- 229910021384 soft carbon Inorganic materials 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- 101100460844 Mus musculus Nr2f6 gene Proteins 0.000 description 1
- 102100023170 Nuclear receptor subfamily 1 group D member 1 Human genes 0.000 description 1
- PFYQFCKUASLJLL-UHFFFAOYSA-N [Co].[Ni].[Li] Chemical compound [Co].[Ni].[Li] PFYQFCKUASLJLL-UHFFFAOYSA-N 0.000 description 1
- DETKHEZXMOBNHJ-UHFFFAOYSA-N [Co].[Ni].[Li].[Li] Chemical compound [Co].[Ni].[Li].[Li] DETKHEZXMOBNHJ-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
- SOXUFMZTHZXOGC-UHFFFAOYSA-N [Li].[Mn].[Co].[Ni] Chemical compound [Li].[Mn].[Co].[Ni] SOXUFMZTHZXOGC-UHFFFAOYSA-N 0.000 description 1
- KQHXRORLXXBUFX-UHFFFAOYSA-N [Mn](=O)(=O)([O-])[O-].[Mn+2].[Ni+2].[Li+] Chemical compound [Mn](=O)(=O)([O-])[O-].[Mn+2].[Ni+2].[Li+] KQHXRORLXXBUFX-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
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- 230000014759 maintenance of location Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
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- 238000011160 research Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
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- 239000007784 solid electrolyte Substances 0.000 description 1
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- 238000005507 spraying Methods 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 229910052905 tridymite Inorganic materials 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
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0404—Methods of deposition of the material by coating on electrode collectors
-
- 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
-
- 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
Abstract
The invention relates to a structure and a method for supplementing lithium to a lithium ion battery based on a lithium silicide composite material.A lithium silicide pole piece is arranged at the bottom in a battery shell and is connected and conducted to a positive pole lug or a negative pole lug of a battery core through a nickel strap; in the first charge and discharge process, the lithium silicide composite material releases lithium ions into the electrolyte to make up for the lithium ions corresponding to the irreversible capacity, so that the first coulombic efficiency of the battery is improved; in the subsequent charge and discharge cycle process, the lithium silicide composite material continuously releases lithium ions into the electrolyte, a lithium battery system always keeps lithium with certain reversible capacity, the capacity attenuation of the battery is reduced, the lithium ions can be continuously released to supplement the lithium for the lithium battery, the lithium supplement is safer and more convenient, the requirements on process equipment and environmental conditions are lower, the operation is simple, the safety is good, and the large-scale production is easy.
Description
Technical Field
The invention belongs to the technical field of lithium ion battery manufacturing, and particularly relates to a structural lithium method for supplementing lithium to a lithium ion battery based on a lithium silicide composite material.
Background
The lithium ion battery has the characteristics of high energy density, long cycle life, high voltage, large power, wide working temperature range and the like, and the excellent characteristics ensure that the lithium ion battery is widely applied to three fields of consumer electronics, power batteries and energy storage. In the first cycle of the lithium ion battery, an SEI film formed on the surface of a graphite cathode has 5% -15% of first irreversible capacity loss, and the loss of a high-capacity silicon-based material is 15% -35%. People research the lithium supplement technology to improve the reversible cycle capacity of the lithium ion battery, and the active lithium compensation is widely concerned. The lithium is supplemented to the pole material by a lithium supplementing technology, so that the active lithium released in the charging process compensates the first irreversible lithium loss, and is used for forming an SEI (solid electrolyte interphase) film on the surface of the negative pole so as to improve the reversible cycle capacity and the cycle life of the lithium battery.
The existing lithium supplementing technology is that a layer of lithium foil (less than 10um) is usually adhered to the surface of a negative pole piece, or a layer of lithium powder is sprayed and evaporated, because metal lithium can react with moisture and nitrogen in the air, the activity of small-particle metal lithium is stronger, and the risk of combustion and explosion exists in the air environment, the large-scale industrial production is difficult to realize by the scheme. The lithium metal is uniformly coated on the negative electrode, lithium dendrites are easily generated at the positions where the lithium metal is not uniformly coated in the subsequent battery circulation process, the contact area of the lithium metal and the diaphragm in the battery is large, and the risk of short circuit of the battery caused by the fact that the dendrites penetrate the diaphragm is large.
The battery structure is redesigned, metal lithium is added as a third pole in the lithium ion battery, a third electrode is led out from the metal lithium to form a pair of electrode with a negative pole, the third electrode and the negative pole are discharged to pre-supplement lithium for the negative pole, and then the battery is formed normally, so that the battery in the technology is complex in design and complex in process.
Disclosure of Invention
In order to solve the problems in the prior art, the invention aims to provide a lithium ion battery lithium supplementing structure and method which can continuously release lithium ions to supplement lithium for a lithium battery, have low requirements on process equipment and environmental conditions, are simple to operate, have good safety and are easy for large-scale production, and are based on a lithium silicide composite material.
The technical scheme adopted by the invention is as follows:
a lithium ion battery lithium supplement structure based on a lithium silicide composite material is characterized in that: the battery comprises a battery shell, wherein battery cores are arranged in the battery shell side by side, and a positive electrode lug and a negative electrode lug of each battery core respectively extend out of the battery shell; a lithium silicide pole piece is arranged in a space between the inner wall of the battery shell and the battery core, a diaphragm is arranged between the lithium silicide pole piece and the battery core, and the lithium silicide pole piece is connected to a positive pole lug or a negative pole lug through a nickel strap.
The lithium silicide pole piece is fixed on the battery core through an adhesive tape.
The battery core is a laminated battery core, the positive electrode lug and the negative electrode lug are respectively arranged at the upper end and the lower end of the laminated battery core, the lithium silicide pole piece is arranged on the side surface of the battery core, and the lithium silicide pole piece is fixedly connected and conducted to the positive electrode lug or the negative electrode lug of the battery chip on the outermost side through a nickel strap.
The battery core is a winding battery core, the positive electrode lug and the negative electrode lug are arranged at the upper end of the winding battery core, and the lithium silicide pole piece is arranged on the inner wall of the battery shell and corresponds to the bottom end of the winding battery core.
The lithium silicide pole pieces are of single-layer structures or multi-layer stacked structures, and each layer of lithium silicide pole piece is separated from the adjacent lithium silicide pole piece through a diaphragm.
The main structure of the lithium silicide pole piece is a current collector, and the surface of the current collector is coated with a composition consisting of a lithium silicide composite material, a carbon black conductive agent and a PVDF binder; the lithium silicide composite material, the carbon black conductive agent and the PVDF binder in the composition are mixed according to the mass ratio of 95: 2: 3 in proportion.
The current collector material is a metal material or a non-metal material; the metal material is copper, nickel or stainless steel, and the nonmetal material is a carbon material; the carbon material is carbon paper, carbon cloth, carbon net, carbon fiber, carbon black, graphite, graphene or carbon nano tube; the diaphragm material is polyethylene, polypropylene or ceramic-coated polyethylene, or ceramic-coated polypropylene and a three-layer co-extrusion diaphragm.
The invention also relates to a method for the structure for lithium supplement of the lithium ion battery based on the lithium silicide composite material, which is characterized by comprising the following steps: the method comprises the following steps:
s1, homogenizing, coating, rolling and cutting the lithium silicide composite material composition and a current collector to prepare a lithium silicide pole piece;
s2, placing a lithium silicide pole piece on a battery core of the lithium ion battery, wherein the lithium silicide pole piece is fixed outside a diaphragm of the battery core through an adhesive tape;
s3, fixedly connecting one end of a nickel strap to a lithium silicide pole piece through welding, and fixedly connecting the other end of the nickel strap to a positive pole lug or a negative pole lug of the battery core through welding;
s4, assembling to form a lithium ion battery;
s5, injecting electrolyte into the lithium ion battery;
and S6, sealing to obtain the finished product of the lithium ion battery.
The step S1 specifically includes the following steps:
s11, preparing a current collector through a mechanical manufacturing process;
s12, the lithium silicide composite material, the carbon black conductive agent and the PVDF binder according to the mass ratio of 95: 2: 3, mixing and stirring uniformly to obtain viscous mixed slurry;
s13, adding a proper amount of N-methyl pyrrolidone, and stirring until the slurry viscosity of the mixture is reduced to 7000 +/-1000 cp;
s14, uniformly coating the mixture slurry on the surface of the current collector;
s15, rolling;
s16, slitting to prepare a lithium silicide pole piece semi-finished product;
s17, sending the mixture into an oven, and vacuumizing to-0.1 MPa;
s18, heating to 80-110 ℃;
s19, baking for 6-8 hours to obtain a finished product of the lithium silicide electrode plate.
The formation current of the lithium ion battery is 0.001-2C, and the first cycle formation current is less than or equal to 0.2C; the lithium supplementing capacity of the lithium silicide pole piece is 0.01-12% of the designed capacity of the lithium ion battery.
The invention has the beneficial effects that:
a lithium ion battery lithium supplement structure and method based on lithium silicide composite material, fixedly set up a lithium silicide pole piece outside the diaphragm of the battery core, the lithium silicide pole piece is connected and conducted to the positive pole lug or negative pole lug of the battery core through the nickel strap; by controlling the charging and discharging current, the control on the lithium supplement amount of a single cycle can be realized, lithium ions can be supplemented into the battery in the first cycle, the first cycle coulombic efficiency of the battery is greatly improved, the follow-up charging and discharging can be realized for continuously supplementing lithium, the cycle life of the battery is prolonged, and the safety risk of lithium supplement by using metal lithium is reduced; in the first charge and discharge process, the lithium silicide composite material releases lithium ions into the electrolyte to make up for the lithium ions corresponding to the irreversible capacity, so that the first coulombic efficiency of the battery is improved; in the subsequent charge and discharge cycle process, the lithium silicide composite material continuously releases lithium ions into the electrolyte, a lithium battery system always keeps lithium with certain reversible capacity, the capacity attenuation of the battery is reduced, the lithium ions can be continuously released to supplement the lithium for the lithium battery, the lithium supplement is safer and more convenient, the requirements on process equipment and environmental conditions are lower, the operation is simple, the safety is good, and the large-scale production is easy.
Drawings
Fig. 1 is a schematic view of a lithium ion battery lithium supplement structure based on a lithium silicide composite material according to the present invention applied to an aluminum can battery;
fig. 2 to 4 are schematic diagrams of the lithium ion battery lithium supplement structure based on the lithium silicide composite material applied to the pouch battery.
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 will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
As shown in fig. 1, the present invention provides a lithium ion battery lithium supplement structure based on a lithium silicide composite material, wherein a basic structure adopts a conventional lithium battery structure, a battery shell is firstly arranged, a battery core is arranged in the battery shell, and a positive electrode tab 1 and a negative electrode tab 2 of the battery core respectively extend out of the battery shell; the main innovation point is that a lithium silicide pole piece 3 is arranged in a space between the inner wall of a battery shell 7 and a battery core, a layer of diaphragm 6 is arranged between the lithium silicide pole piece 3 and the battery core, the lithium silicide pole piece 3 is separated from a positive pole piece and a negative pole piece of the battery core through the diaphragm 6, the lithium silicide pole piece is separated from a pole piece group in the battery, short circuit is prevented, and the diaphragm 6 can also be directly formed by a wrapping film 4 of the battery core; connecting a lithium silicide pole piece 3 to a positive pole tab 1 or a negative pole tab 2 through a nickel strap 5, wherein one end of the nickel strap 5 can be inserted between the inner surface of the lithium silicide pole piece 3 and a diaphragm and is fixedly connected to the inner surface of the lithium silicide pole piece 3 through welding or gluing; the other end of the nickel strap 5 can be fixedly connected to the outer side surface of the positive electrode lug 1 or the negative electrode lug 2 of the battery core through welding or gluing; in the first charge-discharge process, the lithium silicide composite material in the lithium silicide pole piece 3 releases lithium ions into the electrolyte to make up for the lithium ions corresponding to the irreversible capacity, so that the first coulombic efficiency of the battery is improved; in the subsequent charge-discharge cycle process, the lithium silicide composite material continuously releases lithium ions into the electrolyte, a lithium battery system always keeps lithium with certain reversible capacity, the capacity attenuation of the battery is reduced, the lithium can be continuously supplemented, and the safety risk of supplementing lithium by using metal lithium is reduced; the method is safer, more convenient and easier to realize the large-scale application of factories.
Specifically, the lithium silicide pole pieces 3 may be of a single-layer structure, or may be stacked and combined to form a stacked structure through multiple layers of lithium silicide pole pieces 3, and each layer of lithium silicide pole piece is separated from an adjacent layer of lithium silicide pole piece by a diaphragm 6.
The lithium silicide pole piece 3 and the diaphragm 6 are fixed outside the wrapping film 4 of the battery core through adhesive tapes, and when the wrapping film 4 of the battery core directly replaces the diaphragm 6, the lithium silicide pole piece 3 is directly fixed outside the wrapping film 4 of the battery core through the adhesive tapes.
Furthermore, the battery core can be a laminated battery core, a positive electrode tab 1 and a negative electrode tab 2 of the battery core are respectively arranged at the upper end and the lower end of the laminated battery core, a lithium silicide pole piece 3 is arranged on the inner side wall of the battery shell and is vertical to the battery core, an L-shaped nickel strap is adopted, one end of the nickel strap is inserted between the lithium silicide pole piece and the diaphragm and is fixedly connected to the lithium silicide pole piece through welding, and the other end of the nickel strap is fixedly connected to the positive electrode tab 1 or the negative electrode tab 2 of the battery core through welding; the lithium silicide pole piece 3 is fixedly connected and conducted to the positive pole lug 1 or the negative pole lug 2 of the battery chip on the outermost side through the nickel strap 5, and lithium ions can be favorably diffused into the battery along a pole piece gap.
The battery core can also select to coil the electric core, and positive pole utmost point ear 1, negative pole utmost point ear 2 all set up in the upper end of coiling the electric core, and the lithium silicide pole piece sets up in the position that the battery case inner wall corresponds to coiling electric core bottom, also is favorable to lithium ion to the inside diffusion of battery along the pole piece gap.
When the invention is applied to a soft-package battery, as shown in fig. 2-4, a positive electrode tab 11 and a negative electrode tab 22 respectively extend out of two ends of a soft-package battery shell 17 to the outside of the soft-package battery shell 17, a lithium silicide pole piece 13 is arranged at a position corresponding to the soft-package battery 18 in a space between the soft-package battery shell 17 and the soft-package battery 18, namely, the lithium silicide pole piece 13 is arranged at positions on two sides of the soft-package battery 18 and is connected and conducted to the positive electrode tab 1 or the negative electrode tab 2 through a nickel band 15; the specific connection structure of the nickel strap 15 is as follows: one end of the lithium silicide pole piece 13 is provided with a long and narrow connecting section, the connecting section extends to a position close to the negative pole 182 of the edge of the negative pole piece outside the cell diaphragm 19 along the side surface of the soft package cell 18, one end of the long strip-shaped nickel strap 15 is fixedly welded on the connecting section, and the other end of the long strip-shaped nickel strap is fixedly welded on the negative pole 182; or the other end of the lithium silicide pole piece 13 is provided with a long and narrow connecting section, the connecting section extends to the position of the positive pole 181 at the edge of the positive pole piece outside the cell diaphragm 19 along the side surface of the soft-packaged cell 18, one end of the long strip-shaped nickel strap 15 is fixedly welded on the connecting section, and the other end of the long strip-shaped nickel strap is fixedly welded on the positive pole 181; the nickel strap is not shown in fig. 2, and the battery case, the positive electrode tab 11, and the negative electrode tab 22 are not shown in fig. 3 to 4.
Furthermore, the main structure of the lithium silicide pole piece is a current collector, and the surface of the current collector is coated with a composition consisting of a lithium silicide composite material, a carbon black conductive agent and a PVDF binder; the lithium silicide composite material, the carbon black conductive agent and the PVDF binder in the composition are mixed according to the mass ratio of 95: 2: 3 in proportion. The lithium silicide composite material can be a nano lithium silicide composite material prepared from SiO, or can be SiO2The prepared nano lithium silicide composite material.
The gram specific capacity of the lithium silicide composite material was 1540 mAh/g. The composite material has a single structure, and uniformly dispersed active LixSi nano-domain is stably embedded into Li2In the O matrix, the composite material has good stability under the conditions of dry air and ambient air, the capacity attenuation of the composite material in the dry air is negligible, and the LixSi/Li2The capacity retention of the O-composite after 6 hours of exposure to air was still 1200mah/g (40% RH). Due to LixSi/Li2The O composite material has lower potential and can be mixed with various cathode materials in the slurry processing process, so that the first circulation coulombic efficiency is improved. LixSi/Li2The O composite material can be used as a battery negative electrode material with high capacity.
The current collector material can be selected from a metal material or a non-metal material;
the metal material can be selected from copper, nickel or stainless steel, the non-metal material can be selected from carbon materials, and the following carbon materials are specifically selected: carbon paper, carbon cloth, carbon mesh, carbon fiber, carbon black, graphite, graphene, or carbon nanotubes; the diaphragm material can be selected from polyethylene, polypropylene or ceramic-coated polyethylene, or ceramic-coated polypropylene and three-layer co-extruded diaphragm.
The invention also relates to a method for the structure for lithium supplement of the lithium ion battery based on the lithium silicide composite material, which is characterized by comprising the following steps: the method comprises the following steps:
s1, homogenizing, coating, rolling and cutting the lithium silicide composite material composition and a current collector to prepare a lithium silicide pole piece;
s2, placing a lithium silicide pole piece on a battery core of the lithium ion battery, wherein the lithium silicide pole piece is fixed outside a diaphragm of the battery core through an adhesive tape;
s3, fixedly connecting one end of a nickel strap to a lithium silicide pole piece through welding, and fixedly connecting the other end of the nickel strap to a positive pole lug or a negative pole lug of the battery core through welding;
s4, assembling to form a lithium ion battery;
s5, injecting electrolyte into the lithium ion battery;
and S6, sealing to obtain the finished product of the lithium ion battery.
The step S1 of manufacturing the lithium silicide pole piece specifically includes the following steps:
s11, preparing a current collector through a mechanical manufacturing process;
s12, the lithium silicide composite material, the carbon black conductive agent and the PVDF binder according to the mass ratio of 95: 2: 3, mixing and stirring uniformly to obtain viscous mixed slurry;
s13, adding a proper amount of N-methyl pyrrolidone, and stirring until the slurry viscosity of the mixture is reduced to 7000 +/-1000 cp;
s14, uniformly coating the mixture slurry on the surface of the current collector;
s15, rolling;
s16, slitting to prepare a lithium silicide pole piece semi-finished product;
s17, sending the mixture into an oven, and vacuumizing to-0.1 MPa;
s18, heating to 80-110 ℃;
s19, baking for 6-8 hours to obtain a finished product of the lithium silicide electrode plate.
Finally, the formation current of the lithium ion battery is 0.001-2C, and the first cycle formation current is less than or equal to 0.2C; the lithium supplementing capacity of the lithium silicide pole piece is 0.01-12% of the designed capacity of the lithium ion battery.
The lithium silicide composite material synthesized by SiO and lithium metal alloy has a single structure, and active LixSi nano-domain is stably embedded into Li2In the O matrix, the composite material has good stability under the conditions of dry air and ambient air, the capacity attenuation of the composite material in the dry air is negligible, and the LixSi/Li2The capacity of the O-composite remained 1200mah/g (40% RH) after 6 hours of exposure to air. Due to LixSi/Li2The O composite material has lower potential, LixSi/Li2The O composite material can be used as a battery negative electrode material with high capacity.
The lithium silicide composite material and the current collector are made into pole pieces, and the made lithium silicide composite material pole pieces are connected and conducted with the positive electrode or the negative electrode, so that the safety risk of lithium supplement by using metal lithium is reduced; in the first charge and discharge process, the lithium silicide composite material releases lithium ions into the electrolyte to make up for the lithium ions corresponding to the irreversible capacity, so that the first coulombic efficiency of the battery is improved; in the subsequent charge-discharge cycle process, the lithium silicide composite material continuously releases lithium ions into the electrolyte, and a lithium battery system always keeps lithium with certain reversible capacity, so that the capacity attenuation of the battery is reduced, and the lithium can be continuously supplemented. Compared with the prior method of sticking lithium foil on a pole piece, spraying lithium powder, evaporating metal lithium and the like, the method for supplementing lithium by lithium metal is safer and more convenient, and is easier to realize the large-scale application in factories.
1. The lithium supplementing method of the lithium silicide composite material for the lithium ion battery comprises the following steps:
(1) the lithium silicide composite material is made into a pole piece with a certain size through homogenate, coating, rolling and slitting,
firstly, the mass ratio of the lithium silicide composite material to the super P to the PVDF binder is 95: 2: 3, mixing and stirring, adding a proper amount of NMP, stirring to reduce the viscosity to 7000 +/-1000 cp, then uniformly coating the mixture on the surface of a copper foil, rolling and cutting the mixture into a lithium silicide pole piece with a certain size, vacuumizing an oven (80-110 ℃) to-0.1 MPa, and baking for 6-8 hours;
(2) adding a lithium silicide pole piece into the lithium ion battery, isolating the lithium silicide pole piece from a positive plate or a negative plate by using a diaphragm, isolating the lithium silicide pole piece from a pole piece group in the battery, installing the lithium silicide pole piece at the bottom of a battery core, and pasting an adhesive tape on one side of the lithium silicide pole piece, which is in large-area contact with the positive plate and the negative plate; the position of the lithium silicide composite material pole piece is positioned at one side of the battery core pole piece group, particularly the cross section position of the battery core, because of the diaphragm, especially the contact surface of the diaphragm and the anode and the cathode is pasted with the adhesive tape, a certain distance is not needed to be kept, and lithium ions released by the lithium silicide pole piece can conveniently enter the battery core from a gap between the pole piece groups of the battery core and can be diffused;
(3) connecting and conducting the lithium silicide pole piece with the positive electrode or the negative electrode of the battery core through a nickel strap, and assembling the battery;
(4) the lithium ion battery is injected with electrolyte, and the lithium silicide composite material releases lithium ions into the electrolyte in the formation and subsequent circulation processes, so that the purpose of supplementing lithium to the lithium ion battery is achieved.
2. The battery core of the lithium ion battery is of a winding structure or a lamination structure, the lithium silicide pole piece is positioned at one side of the battery core, specifically, the cross section of the battery core, so that lithium ions can be favorably diffused into the battery core along a pole piece gap, and the lithium silicide pole piece can be one layer or multiple layers.
3. The lithium silicide pole piece is made by pulping lithium silicide composite material, super P, NMP and other solvents and coating the pulp on a current collector.
4. The current collector comprises a metal material and a carbon material, wherein the metal material is copper, nickel or stainless steel; the carbon material is carbon paper, carbon cloth, carbon net, carbon fiber, carbon black, graphite, graphene or carbon nano tube;
5. the diaphragm is polyethylene, polypropylene or ceramic coated polyethylene, or ceramic coated polypropylene or three-layer co-extrusion diaphragm.
6. The formation current of the lithium ion battery is 0.001-2C. 0.01-2C is the formation current range, which in the typical example takes a fixed value such as 0.1C, 0.5C, 1C, etc.
7. The lithium filling capacity of the lithium silicide composite material is 0.01-12% of the designed capacity of the lithium ion battery.
8. The anode material of the lithium ion battery comprises lithium iron phosphate, lithium cobaltate, lithium manganate, lithium nickelate, lithium nickel manganate, lithium nickel cobalt manganate ternary material, lithium nickel cobalt aluminate ternary material, lithium-rich manganese-based material, elemental sulfur, carbon-sulfur compound, FeS2、V2O5、MnO2、FeF3、CoF3、MnF3One or more of them.
9. The negative electrode material of the lithium ion battery comprises metallic lithium, artificial graphite, natural graphite, a mesophase carbon material, hard carbon, soft carbon, porous carbon, lithium titanate, silicon oxide, a silicon-carbon composite material, tin, stannous oxide, stannic oxide, a stannic-carbon composite material, an alloy negative electrode material and a metal oxide negative electrode material.
The invention relates to the technical field of lithium ion battery lithium supplement, in particular to a lithium ion battery lithium supplement method by a lithium silicide composite material.
The invention provides the lithium-supplementing method for the lithium silicide composite material, which has lower requirements on process equipment and environmental conditions, is simple to operate, has good safety and is easy for large-scale production.
The lithium ion battery lithium supplementing method by the lithium silicide composite material comprises the following steps:
(1) firstly, the mass ratio of the lithium silicide composite material to the super P to the PVDF binder is 95: 2: 3, mixing and stirring, adding a proper amount of NMP, stirring to reduce the viscosity to 7000 +/-1000 cp, then uniformly coating the mixture on the surface of a copper foil, rolling and cutting the mixture into pole pieces with a certain size, vacuumizing an oven (80-110 ℃) to-0.1 MPa, and baking for 6-8 hours;
(2) adding a lithium silicide pole piece into the lithium ion battery, isolating the lithium silicide pole piece from a positive pole piece and a negative pole piece of the battery core by a diaphragm,
(3) connecting and conducting the lithium silicide pole piece with the positive electrode or the negative electrode, and assembling the battery;
(4) the lithium ion battery is injected with electrolyte, and the lithium silicide composite material releases lithium ions into the electrolyte in the formation and subsequent circulation processes, so that the purpose of supplementing lithium to the lithium ion battery is achieved.
According to the invention, the lithium silicide composite material is made into the pole piece, so that the defects that lithium supplement safety of metal lithium is poor and large-scale application is not facilitated are avoided; meanwhile, the control of the lithium supplement amount of the single cycle can be realized by controlling the charging and discharging current, the lithium ions can be supplemented into the battery in the first cycle, the first cycle coulombic efficiency of the battery is greatly improved, the follow-up charging and discharging can be realized, and the cycle life of the battery is prolonged.
As a preferred scheme of the present invention, the battery cell in the lithium ion battery is of a winding structure and a lamination structure, the lithium silicide composite material pole piece is located at a side position of the pole piece group, specifically, at a cross-sectional position of the battery cell, which is conducive to lithium ion diffusion into the battery along a pole piece gap, and the lithium silicide composite material pole piece may be one layer or multiple layers.
As a preferred embodiment of the present invention, the lithium silicide composite electrode plate is an electrode plate composed of a lithium silicide composite material and a conductive current collector.
As a preferred scheme of the present invention, the conductive current collector includes a metal material and a carbon material, the metal material is copper, nickel or stainless steel, and the carbon material is carbon paper, carbon cloth, carbon mesh, carbon fiber, carbon black, graphite, graphene or carbon nanotube;
as a preferable scheme of the invention, the diaphragm is polyethylene, polypropylene, ceramic-coated polyethylene or ceramic-coated polypropylene, and a three-layer co-extrusion diaphragm.
In a preferred embodiment of the present invention, the formation current of the lithium ion battery is 0.001-2C, preferably the first cycle formation current of the battery is less than or equal to 0.2C, and a small current helps lithium ions to uniformly diffuse into the battery. The lithium supplementing capacity of the lithium silicide is 0.01-120% of the designed capacity of the lithium ion battery.
As a preferred scheme of the present invention, the positive electrode material of the lithium ion battery includes lithium iron phosphate, lithium cobaltate, lithium manganate, lithium nickelate, lithium nickel manganate, lithium nickel manganese manganate ternary material, lithium nickel cobalt lithium aluminate ternary material, lithium-rich manganese-based material, elemental sulfur, carbon-sulfur complex, FeS2、V2O5、MnO2、FeF3、CoF3、MnF3One or more of them.
As a preferred scheme of the invention, the negative electrode material of the lithium ion battery comprises one or more of metallic lithium, artificial graphite, natural graphite, a mesophase carbon material, hard carbon, soft carbon, porous carbon, lithium titanate, silicon oxide, a silicon-carbon composite material, tin, stannous oxide, stannic oxide, a stannic-carbon composite material, an alloy negative electrode material and a metal oxide negative electrode material;
according to the invention, the lithium silicide composite material is made into the pole piece, and the pole piece of the lithium silicide composite material is connected and conducted with the positive electrode or the negative electrode, so that the safety risk of lithium supplement by using metal lithium is reduced; in the first charge and discharge process, the lithium silicide composite material releases lithium ions into the electrolyte to make up for the lithium ions corresponding to the irreversible capacity, so that the first coulombic efficiency of the battery is improved; in the subsequent charge-discharge cycle process, the lithium silicide composite material continuously releases lithium ions into the electrolyte, and a lithium battery system always keeps lithium with certain reversible capacity, so that the capacity attenuation of the battery is reduced, and the lithium can be continuously supplemented. Compared with the existing method for supplementing lithium by using lithium metal, the method is safer and more convenient, and is easier to realize large-scale application in factories.
The invention is further illustrated below with reference to the figures and examples.
Example 1:
in the lithium ion battery lithium supplement method provided by the embodiment, the capacity of the lithium ion battery in the embodiment is 25Ah wound battery, lithium iron phosphate is used as a positive electrode, artificial graphite is used as a negative electrode, and copper foil is used as a current collector; the lithium silicide composite material is made into a pole piece with a certain size through homogenizing, coating and cutting, the pole piece is placed at the bottom of the lithium ion battery after being wrapped by a diaphragm, a copper foil of the lithium silicide pole piece is connected and conducted with a negative current collector, and the lithium silicide pole piece is packaged, injected with electrolyte and kept stand. The lithium-ion battery is formed for the first time by using 0.01C low current, the first charging capacity is 27.2Ah, the discharging capacity is 26.5Ah, and the first coulombic efficiency is 97.4 percent and is improved by 5.6 percent compared with the first coulombic efficiency (91.8 percent) of a battery without lithium supplement. In other embodiments, the pole piece group in the lithium ion battery may also adopt a lamination structure, and then the lithium silicide negative pole piece is arranged at one side of the pole piece group.
Example 2:
according to the lithium ion battery lithium supplement method provided by the embodiment, the capacity of the lithium ion battery in the embodiment is 25Ah wound battery, lithium iron phosphate is used as a positive electrode, a 650mAh/g silicon-carbon and graphite composite material is used as a negative electrode, and copper foil is used as a current collector; the lithium silicide composite material is made into a pole piece with a certain size through homogenate, coating and slitting, the pole piece is placed at the bottom of a lithium ion battery after being wrapped by a diaphragm, a copper foil of the lithium silicide pole piece is connected and conducted with a negative current collector, electrolyte is packaged and injected, the lithium silicide pole piece is stood still, first cycle formation is carried out by using 0.01C low current, the first cycle charging capacity is 27.6Ah, the discharging capacity is 25.8Ah, the first coulombic efficiency is 93.4%, and the first cycle efficiency is 12.9% higher than that of the battery without lithium supplement (80.5%).
Example 3:
according to the lithium ion battery lithium supplement method provided by the embodiment, the capacity of the lithium ion battery in the embodiment is a 25Ah laminated battery, nickel lithium manganate is taken as a positive electrode, a 650mAh/g silicon-carbon and graphite composite material is taken as a negative electrode, and copper foil is taken as a current collector; the lithium silicide composite material is made into a pole piece with a certain size through homogenizing, coating and cutting, the pole piece is placed at the bottom of the lithium ion battery after being wrapped by a diaphragm, a copper foil of the lithium silicide pole piece is connected and conducted with a negative current collector, and the lithium silicide pole piece is packaged, injected with electrolyte and kept stand. The first-cycle formation is carried out by using 0.01C low current, the first-cycle charging capacity is 30Ah, the discharging capacity is 27.2Ah, and the first coulombic efficiency is 90.6 percent and is improved by 10.6 percent compared with the first-cycle efficiency (80 percent) of a battery without lithium supplement.
Example 4:
according to the lithium ion battery lithium supplement method provided by the embodiment, the capacity of the lithium ion battery is 25Ah, the lithium nickel cobalt manganese 523 ternary material is used as a positive electrode, a 650mAh/g silicon carbon and graphite composite material is used as a negative electrode, and a copper foil is used as a current collector; the lithium silicide composite material is made into a pole piece with a certain size through homogenizing, coating and cutting, the pole piece is placed at the bottom of the lithium ion battery after being wrapped by a diaphragm, a copper foil of the lithium silicide pole piece is connected and conducted with a negative current collector, and the lithium silicide pole piece is packaged, injected with electrolyte and kept stand. The first-cycle formation is carried out by using 0.01C low current, the first-cycle charging capacity is 30.5Ah, the discharging capacity is 28.7Ah, and the first coulombic efficiency is 94.1 percent, which is 10.3 percent higher than the first-cycle efficiency (83.8 percent) of the battery without lithium supplement.
Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and modifications and variations of the present invention are also intended to fall within the scope of the appended claims. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. Other methods, which may be obtained by the same or similar steps as those described in the above embodiments of the present invention, are within the scope of the present invention.
Claims (10)
1. A lithium ion battery lithium supplement structure based on a lithium silicide composite material is characterized in that: the battery comprises a battery shell, wherein battery cores are arranged in the battery shell side by side, and a positive electrode lug and a negative electrode lug of each battery core respectively extend out of the battery shell; a lithium silicide pole piece is arranged in a space between the inner wall of the battery shell and the battery core, a diaphragm is arranged between the lithium silicide pole piece and the battery core, and the lithium silicide pole piece is connected to a positive pole lug or a negative pole lug through a nickel strap.
2. The structure for lithium ion battery lithium supplement based on lithium silicide composite material according to claim 1, wherein: the lithium silicide pole piece is fixed on the battery core through an adhesive tape.
3. The structure for lithium ion battery lithium supplement based on lithium silicide composite material according to claim 1, wherein: the battery core is a laminated battery core, the positive electrode lug and the negative electrode lug are respectively arranged at the upper end and the lower end of the laminated battery core, the lithium silicide pole piece is arranged on the side surface of the battery core, and the lithium silicide pole piece is fixedly connected and conducted to the positive electrode lug or the negative electrode lug of the battery chip on the outermost side through a nickel strap.
4. The structure for lithium ion battery lithium supplement based on lithium silicide composite material according to claim 1, wherein: the battery core is a winding battery core, the positive electrode lug and the negative electrode lug are arranged at the upper end of the winding battery core, and the lithium silicide pole piece is arranged on the inner wall of the battery shell and corresponds to the bottom end of the winding battery core.
5. The structure for lithium ion battery lithium supplement based on lithium silicide composite material according to claim 1, wherein: the lithium silicide pole pieces are of single-layer structures or multi-layer stacked structures, and each layer of lithium silicide pole piece is separated from the adjacent lithium silicide pole piece through a diaphragm.
6. The structure for lithium ion battery lithium supplement based on lithium silicide composite material according to claim 1, wherein: the main structure of the lithium silicide pole piece is a current collector, and the surface of the current collector is coated with a composition consisting of a lithium silicide composite material, a carbon black conductive agent and a PVDF binder; the lithium silicide composite material, the carbon black conductive agent and the PVDF binder in the composition are mixed according to the mass ratio of 95: 2: 3 in proportion.
7. The structure for lithium ion battery lithium supplement based on lithium silicide composite material according to claim 6, wherein: the current collector material is a metal material or a non-metal material; the metal material is copper, nickel or stainless steel, and the nonmetal material is a carbon material; the carbon material is carbon paper, carbon cloth, carbon net, carbon fiber, carbon black, graphite, graphene or carbon nano tube; the diaphragm material is polyethylene, polypropylene or ceramic-coated polyethylene, or ceramic-coated polypropylene and a three-layer co-extrusion diaphragm.
8. A method for supplementing lithium to a lithium ion battery based on a lithium silicide composite material is characterized in that: the method comprises the following steps:
s1, homogenizing, coating, rolling and cutting the lithium silicide composite material composition and a current collector to prepare a lithium silicide pole piece;
s2, placing a lithium silicide pole piece on a battery core of the lithium ion battery, wherein the lithium silicide pole piece is fixed outside a diaphragm of the battery core through an adhesive tape;
s3, fixedly connecting one end of a nickel strap to a lithium silicide pole piece through welding, and fixedly connecting the other end of the nickel strap to a positive pole lug or a negative pole lug of the battery core through welding;
s4, assembling to form a lithium ion battery;
s5, injecting electrolyte into the lithium ion battery;
and S6, sealing to obtain the finished product of the lithium ion battery.
9. The method of claim 8, wherein the lithium ion battery is lithium-supplemented based on the lithium silicide composite material, and the method comprises: the method comprises the following steps: the step S1 specifically includes the following steps:
s11, preparing a current collector through a mechanical manufacturing process;
s12, the lithium silicide composite material, the carbon black conductive agent and the PVDF binder according to the mass ratio of 95: 2: 3, mixing and stirring uniformly to obtain viscous mixed slurry;
s13, adding a proper amount of N-methyl pyrrolidone, and stirring until the slurry viscosity of the mixture is reduced to 7000 +/-1000 cp;
s14, uniformly coating the mixture slurry on the surface of the current collector;
s15, rolling;
s16, slitting to prepare a lithium silicide pole piece semi-finished product;
s17, sending the mixture into an oven, and vacuumizing to-0.1 MPa;
s18, heating to 80-110 ℃;
s19, baking for 6-8 hours to obtain a finished product of the lithium silicide electrode plate.
10. The method of claim 8, wherein the lithium ion battery is lithium-supplemented based on the lithium silicide composite material, and the method comprises: the formation current of the lithium ion battery is 0.001-2C, and the first cycle formation current is less than or equal to 0.2C; the lithium supplementing capacity of the lithium silicide pole piece is 0.01-12% of the designed capacity of the lithium ion battery.
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| WO2023024404A1 (en) * | 2021-08-27 | 2023-03-02 | 合肥国轩高科动力能源有限公司 | Lithium-ion battery pre-lithiation method and lithium-ion battery |
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Application publication date: 20210713 |