CN103515607B - A kind of lithium ion battery cathode slurry, negative pole and battery - Google Patents
A kind of lithium ion battery cathode slurry, negative pole and battery Download PDFInfo
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- CN103515607B CN103515607B CN201210214393.7A CN201210214393A CN103515607B CN 103515607 B CN103515607 B CN 103515607B CN 201210214393 A CN201210214393 A CN 201210214393A CN 103515607 B CN103515607 B CN 103515607B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0404—Methods of deposition of the material by coating on electrode collectors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/04—Processes of manufacture in general
- H01M4/043—Processes of manufacture in general involving compressing or compaction
- H01M4/0435—Rolling or calendering
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/133—Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/027—Negative electrodes
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
The lithium ion battery negative that the invention provides a kind of lithium ion battery cathode slurry and prepare with this cathode size and battery.This lithium ion battery cathode slurry, comprise negative active core-shell material, binding agent, solvent and pore creating material, described pore creating material is selected from one or more in azo-compound and/or sulfonyl hydrazines compound, when ensureing that cathode pole piece compacted density does not reduce, the porosity of pole piece can be improved, increase even pore distribution, improve the area of the effective conducting lithium ions of liquid phase, while ensureing battery high energy metric density, improve high rate performance and the cryogenic property of battery, capacity have also been obtained raising simultaneously.
Description
Technical field
The lithium ion battery negative that the present invention relates to a kind of lithium ion battery cathode slurry and adopt cathode size of the present invention obtained and lithium ion battery.
Background technology
Lithium ion battery is now widely used secondary cell, and it has, and specific energy is high, operating voltage is high, self-discharge rate is low, have extended cycle life, the advantage such as pollution-free.Be widely used in the field such as electric tool, electric automobile, it not only requires that energy density is high, has extended cycle life, consistency is good, fail safe is good, cost is low, also requires to have high specific power, excellent high-rate charge-discharge capability.Therefore improving lithium ion battery rate charge-discharge performance applies significant to it.
The diffusion transport of lithium ion in cathode pole piece weighs the important performance indexes of battery rate charge-discharge performance quality.Open-cell porosity in cathode pole piece decides the diffusion transport of lithium ion, porosity is higher, more be conducive to the raising to electrode interior transmission speed of lithium ion and electrolyte, be conducive to lithium ion simultaneously in negative active core-shell material, embed the increase of deviating from passage and direction, thus make battery specific power high, there is excellent high-rate charge-discharge capability.But porosity is higher, the bulk density of active material is lower, the energy density of battery is also lower, therefore, lithium ion battery negative electrode needs usually through compressing tablet to improve compacted density, and then improves battery energy density, through the cathode pole piece of compacting, porosity reduces, and the particularly formation of surperficial closed pore, makes electrolyte be difficult to active material internal penetration, cause lithium ion in electrode, be difficult to transport, finally make performance of lithium ion battery deterioration.
At present, the compacted density of ordinary graphite negative pole is generally 1.2-1.6g/cm
3porosity is 20%-50%, and porosity distribution is uneven, the decrement of pole piece is large, aperture is little, and closed pore phenomenon is serious, true pole piece porosity about 10%, although lithium ion diffusion coefficient is in the liquid phase far above the diffusion coefficient in graphite, the surface area of graphite is 10 of effective liquid phase diffusion area
3-10
6doubly, cathode pole piece is thicker, compacting is larger, and difference is larger.Add bottleneck effect, effective mass transfer in liquid phase area is less, lithium ion solid phase and liquid phase diffusion impedance very close.
In the charge and discharge process of battery, when the current increases, because mass transfer in liquid phase area is little, current density increases sharply, and the impedance that mass transfer in liquid phase produces occupies higher ratio in total impedance, very large on battery charging and discharging impact, and current density is larger, affects larger.When the temperature decreases, the viscosity of electrolyte increases fast, and the transfer impedance of lithium ion in hole becomes large, produces and seriously polarizes.Therefore, the distributing homogeneity in cathode pole piece porosity and hole governs multiplying power and the cryogenic property of battery.
Existing have the electrode of openly a kind of chargeable lithium cell to comprise collector, active material layer, on a current collector, wherein, active material layer comprises active material, binding agent and pore-creating polymer, wherein, active material is suitable for embedding and the deintercalation of reversibly carrying out lithium ion, after it makes battery, pore-creating dissolution of polymer is in electrolyte solution, thus in active layer (or electrode active material layers), play the change being used for buffer volumes forming hole, thus the expansion of electrode and battery can be suppressed, improve the cycle life characteristics of battery, electrode is applicable to negative pole, the optional free polyalkylene carbonic ether of pore-creating polymer, polyalkylene oxides, poly-alkylsiloxane, polyalkyl acrylate, polyalkyl methacrylate, material in the group of their copolymer and the mixture composition of above-mentioned polymer.But pore-creating polymer cannot form perforate efficiently in this technical scheme; And pore-creating polymer may be surrounded by active material and cannot with electrolyte contacts, in this case, pore-creating polymer not only cannot play the effect of pore-forming, and may affect the performance such as capacity, multiplying power of battery due to the residual of pore-creating polymer.
Summary of the invention
Negative pole porosity when guaranteeing metric density that the present invention is prepared in order to the cathode size overcoming prior art is low and pore size distribution uneven particularly top layer closed pore phenomenon is serious, the battery multiplying power of preparation and the problem of poor performance at low temperatures, provide a kind of can prepare porosity lithium ion battery cathode slurry that is high, the particularly negative pole of even pore distribution and prepare with this cathode size lithium ion battery negative and battery.
First object of the present invention is to provide a kind of lithium ion battery cathode slurry, comprises negative active core-shell material, binding agent, solvent and pore creating material, and wherein, pore creating material is selected from one or more in azo-compound and/or sulfonyl hydrazines compound.
Second object of the present invention is to provide a kind of lithium ion battery negative, and this negative pole is coated on negative electrode collector by above-mentioned cathode size, and drying, calendering, heat treatment prepare, and wherein, the porosity of negative pole is 20 ~ 50%.
3rd object of the present invention is to provide a kind of lithium ion battery, this battery battery container and the electrode group be sealed in this battery container and electrolyte; Described electrode group comprises positive pole, negative pole and the barrier film between positive pole and negative pole, and wherein, described negative pole is above-mentioned lithium ion battery negative.
The present inventor surprisingly finds that technical scheme of the present invention is when ensureing that cathode pole piece compacted density does not reduce, the porosity of pole piece can be improved, increase even pore distribution, improve the area of the effective conducting lithium ions of liquid phase, while ensureing battery high energy metric density, improve high rate performance and the cryogenic property of battery.Cathode size of the present invention is when preparing pole piece, azo-compound in cathode size and this kind of pore creating material of sulfonyl hydrazines compound can itself be present in cathode pole piece with solid state, and be evenly distributed, when in heat treatment process prepared by pole piece, decompose, effusion makes its former position occupied become hole in gaseous form, and, numerous passages that the effusion of gas is formed also ensure that the open-cell porosity that pole piece is high, and the porous nickel distribution formed, particularly the present invention forms the hole with extraneous UNICOM by the heat treatment of pore creating material, i.e. perforate, further increase the open-cell porosity of pole piece, surface pore is abundanter, be conducive to improving lithium ion and electrolyte to electrode interior transmission speed, be conducive to increasing lithium ion to embed in negative active core-shell material and deviate from passage and direction simultaneously, thus make the battery of preparation have good high-rate charge-discharge capability and cryogenic property.The decomposition temperature of azo-compound and sulfonyl hydrazines compound is low simultaneously, more easily decomposes, also not easily remains, and the impact of not easily receptor 1 activity material etc., other performances of battery can not be affected, the gas uniform produced during thermal decomposition, uniform pore space structure can be caused on pole piece.And method of the present invention is simple and easy to realize.
Accompanying drawing explanation
Fig. 1 is that the battery S11 of embodiment 1 preparation is with the voltage-time curve figure of 10C current charges.
Fig. 2 is that the battery DS11 of comparative example 1 preparation is with the voltage-time curve figure of 10C current charges.
Fig. 3 is that the battery DS22 of comparative example 2 preparation is with the voltage-time curve figure of 10C current charges.
Embodiment
In order to make technical problem solved by the invention, technical scheme and beneficial effect clearly understand, below in conjunction with embodiment, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
The invention provides a kind of lithium ion battery cathode slurry, comprise negative active core-shell material, binding agent, solvent and pore creating material, wherein, pore creating material is selected from one or more in azo-compound and/or sulfonyl hydrazines compound, when ensureing that cathode pole piece compacted density does not reduce, the porosity of pole piece can be improved, increasing even pore distribution, improve the area of the effective conducting lithium ions of liquid phase, while ensureing battery high energy metric density, improve high rate performance and the cryogenic property of battery.
Preferably, pore creating material is selected from Celogen Az, unifor or 4, one or more in 4'-disulfonyl hydrazide diphenyl ether, the performance of pole piece after the performance of further optimization slurry and heat treatment, can not cause harmful effect etc. to pole piece, and this kind of material more can ensure the homogeneity of foaming and low residual quantity.
Preferably, the mean particle size of pore creating material is 0.2 ~ 4um, and preferably the mean particle size of pore creating material is 0.5 ~ 2.5um further, optimizes the pore space structure of pole piece further, optimize the energy density of the porosity of pole piece, the aperture of pore-creating and pole piece, the combination property of further preferred battery.
Preferably, the decomposition temperature of pore creating material is 105 ~ 150 DEG C, and after decomposing, residual ash is not higher than 0.5%, and preferably residue, not higher than 0.2%, easily decomposes low-residual, can not bring harmful effect to pole piece, battery further.
Preferably, relative to the negative active core-shell material of 100 weight portions, the content of described pore creating material is 1 ~ 6 weight portion, and more preferably 2 ~ 4 weight portions optimize the porosity of pole piece and the energy density of battery further.
The kind of solvent can adjust according to the kind of negative active core-shell material and binding agent.Preferably, solvent can be water or water-soluble solvent, azo-compound of the present invention and this type of material of sulfonyl hydrazines compound are not allowed or slightly soluble in water, exist in solid form in the slurry, be dispersed in solid form in the active material layer of negative pole after applying slurry on a current collector, its special performance can be played.Water system slurry when water makees solvent has non-environmental-pollution, low cost and other advantages, is conducive to a large amount of technology and produces.Now in better situation, binding agent is water-based binder, and the preferred water-based binder of the present invention is selected from one or more in polyvinyl fluoride, polyvinyl chloride or butadiene-styrene rubber.
Negative active core-shell material the present invention do not limit, the various negative active core-shell materials that can be known to the skilled person, such as native graphite, one or more in Delanium or hard charcoal, and wherein, the grain diameter of negative active core-shell material is 5 microns-50 microns.Wherein, ratio the present invention of negative active core-shell material, binding agent and solvent is not particularly limited, can adjust flexibly material concentration according to the viscosity of slurry coating of the composition of battery electrode active material, binding agent and cathode size to be prepared and the requirement of operability, mode is conventionally known to one of skill in the art.In general with the total amount of negative active core-shell material for benchmark, the consumption of binding agent is 2 ~ 6wt%, and the consumption of solvent is 110 ~ 150wt%.
Cathode size of the present invention also can comprise conductive agent to increase the conductivity of electrode, reduces the internal resistance of cell.Conductive agent the present invention do not limit, the various conductive agents that can be known to the skilled person, such as conductive black, nickel powder, copper powder etc.With the weight of negative active core-shell material for benchmark, the content of described conductive agent is preferably 1 ~ 4 % by weight.
Cathode size of the present invention also can comprise thickener, make the slurries better effects if obtained, described thickener is the various high molecular polymers that can increase viscosity, such as, in the cellulose etherses such as methylcellulose (MC), ethyl cellulose (EC), carboxymethyl cellulose (CMC), carboxylic propyl methocel (HPMC) and polyacrylamide (PAM), polyvinyl alcohol (PVA) etc. one or more, (ok) its kind is conventionally known to one of skill in the art.In general, according to the difference of thickener kind used, with the weight of negative active core-shell material for benchmark, the consumption of thickener is preferably 1 ~ 3 % by weight.
Wherein, also can add other property-modifying additives in lithium ion battery cathode slurry, the present invention does not limit, design according to actual needs, such as can add dispersant, improve the paintability of slurry, dispersant can be polyvinyl alcohol, tartrate, citrate etc.
Wherein, preparation the present invention of cathode size does not limit, can by negative active core-shell material, binding agent, the mixed preparing such as solvent and pore creating material form slurry, the order of mixing and mode the present invention are without particular/special requirement, as long as they can be mixed, such as binding agent and solvent can be made mixed solution, by negative active core-shell material, the particles such as pore creating material are mixed into mixture to be added to together in mixed solution and stirs, in better situation, the present invention is specifically as follows and joins in solvent by thickener, stir be less than the condition of-0.08MPa in vacuum degree under and obtain mixed solution in 2 ~ 4 hours, then by conductive agent, binding agent, negative electrode active material, pore creating materials etc. add in mixed solution, fully stir 6 ~ 8 hours be less than the condition of-0.08MPa in vacuum degree under, obtain cathode size.
Invention also provides a kind of lithium ion battery negative, be coated on negative electrode collector by above-mentioned cathode size, drying, calendering, heat treatment prepare, and the porosity of described negative pole is 20 ~ 50%.
Preferably, heat treated vacuum degree is less than-0.08MPa, and temperature is 110 ~ 160 DEG C, and the preferred heat treated time is 10 ~ 25min, optimizes pore structure further.
Wherein, the various negative electrode collectors that negative electrode collector is known to the skilled person, such as, can be selected from one or more in aluminium foil, Copper Foil, nickel plated steel strip, Punching steel strip.In better situation, be specifically as follows the Copper Foil of 8 ~ 15um.
Wherein, coating, drying, the step of calendering, the present invention can adopt the technology of well known to a person skilled in the art, preferably, drying is carried out under vacuum at 80 ~ 105 DEG C.Calendering can be carried out in roller machine, and adopt the rolling condition that this area is conventional, such as 0.5-3.0 MPa, the speed of preferably calendering is 10 ~ 20m/min.
The preparation of negative pole can also comprise other steps, and such as, the cut-parts of reprocessing, cut-parts are known to the skilled person, and after heat treatment is complete, cuts, obtain cathode pole piece according to the negative pole size of prepared battery request.
Preferably, cathode pole piece thickness prepared by the present invention is 90 ~ 150um, and compacted density is 1.20 ~ 1.45g/cm
3.
Present invention also offers a kind of lithium ion battery, comprise battery container and the electrode group be sealed in this battery container and electrolyte; Described electrode group comprises positive pole, negative pole and the barrier film between positive pole and negative pole, and wherein, described negative pole is above-mentioned lithium ion battery negative.
The present invention to the preparation method of described lithium ion battery without particular/special requirement, can carry out with reference to prior art, in general, by barrier film, positive pole and negative pole winding are separated formation electrode group, electrode group is inserted in battery case, adds electrolyte, then seal, wherein, the method for winding and sealing is that those skilled in the art are known.The consumption of electrolyte is conventional amount used.Lithium ion battery provided by the invention can be obtained.Follow-uply also have ageing, the conventional steps such as to change into, do not repeat them here.
Because the present invention only relates to the improvement to prior art lithium ion secondary battery negative pole, therefore other the Nomenclature Composition and Structure of Complexes of lithium rechargeable battery is had no particular limits.Such as the positive pole of battery, barrier film and electrolyte are had no particular limits, all types of positive poles, barrier film and the electrolyte that can use in lithium rechargeable battery can be used.Those of ordinary skill in the art can according to the instruction of prior art, can select and prepare the positive pole of lithium rechargeable battery of the present invention, barrier film and electrolyte easily, and obtain lithium rechargeable battery of the present invention by described positive pole, negative pole of the present invention, barrier film and electrolyte, do not repeat them here.
Consisting of of described positive pole is conventionally known to one of skill in the art.In general, the preparation of positive pole adopts and well known to a person skilled in the art technology, and such as positive pole comprises and is coated on positive electrode collector by anode sizing agent, and drying, calendering prepare.Anode sizing agent generally comprises positive active material, conductive agent, positive electrode binder and positive pole solvent.
The kind of described positive electrode collector has been conventionally known to one of skill in the art, such as, can be selected from aluminium foil, Copper Foil, Punching steel strip.In the specific embodiment of the present invention, use aluminium foil as positive electrode collector.
The kind of the binding agent in described positive electrode and content are conventionally known to one of skill in the art, and such as fluorine resin and polyolefin compound are as one or more in polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE) and butadiene-styrene rubber (SBR).In general, according to the difference of adhesive therefor kind, with the weight of positive active material for benchmark, the content of binding agent is 0.01-10wt%, is preferably 0.02-5wt%.
The present invention is not particularly limited described positive active material, for any positive active material that can be purchased in prior art, such as, can adopt all positive active materials that can be purchased, as LiFePO
4, Li
3v
2(PO
4)
3, LiMn
2o
4, LiMnO
2, LiNiO
2, LiCoO
2, LiVPO
4f, LiFeO
2; Or ternary system Li
1+al
1-b-cm
bn
co
2, a, b, c represent molal quantity separately, wherein-0.1≤a≤0.2,0≤b≤1,0≤c≤1,0≤b+c≤1.0, and L, M, N are one or more in Co, Mn, Ni, Al, Mg, Ga, Sc, Ti, V, Cr, Fe, Cu and Zn.
The present invention is not particularly limited described positive conductive agent, can be the positive conductive agent of this area routine, at least one in such as acetylene black, conductive carbon black and electrically conductive graphite.Wherein, with the weight of positive active material for benchmark, the content of described positive conductive agent is 0.5-15wt%, is preferably 1-10wt%.
According to the present invention, described barrier film is arranged between positive pole and negative pole, has electrical insulation capability and liquid retainability energy.Described barrier film can be selected from various barrier films used in lithium ion battery, as polyolefin micro porous polyolefin membrane, polyethylene felt, glass mat or ultra-fine fibre glass paper.The position of described barrier film, character and kind are conventionally known to one of skill in the art.
The preparation method of concrete positive pole can for be prepared into positive electrode slurries with positive pole solvent by positive active material, positive electrode binder and conductive agent, the requirement of the viscosity that the addition of positive pole solvent can be coated with according to the slurry of positive pole slurries to be prepared and operability adjusts flexibly, then the positive pole slurries obtained are coated on plus plate current-collecting body, dry compressing tablet, then cut-parts obtain positive pole.When the positive active material of above-mentioned positive electrode composition, positive electrode binder and conductive agent being prepared into positive electrode slurries with solvent, reinforced order is not asked especially.Dry temperature can be 80-150 DEG C, and drying time can be 2-10 hour.Method and the condition of calendering are method known in those skilled in the art.Positive pole solvent can be various positive pole solvent of the prior art, as being selected from one or more in 1-METHYLPYRROLIDONE (NMP), dimethyl formamide (DMF), diethylformamide (DEF), dimethyl sulfoxide (DMSO) (DMSO), oxolane (THF) and water and alcohols.The consumption of positive pole solvent enables anode sizing agent be coated on conducting base.
Described electrolyte is the mixed solution of electrolyte lithium salt and nonaqueous solvents, is not particularly limited it, can use the nonaqueous electrolytic solution of this area routine.Such as electrolyte lithium salt be selected from lithium hexafluoro phosphate (LiPF6), lithium perchlorate, LiBF4, hexafluoroarsenate lithium, lithium halide, chlorine lithium aluminate and fluorocarbon based Sulfonic Lithium one or more.Organic solvent selects chain acid esters and ring-type acid esters mixed solution, wherein chain acid esters can be dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), methyl propyl carbonate (MPC), dipropyl carbonate (DPC) and other is fluorine-containing, sulfur-bearing or at least one contained in the chain organosilane ester of unsaturated bond, ring-type acid esters can be ethylene carbonate (EC), propene carbonate (PC), vinylene carbonate (VC), gamma-butyrolacton (γ-BL), sultone and other is fluorine-containing, sulfur-bearing or at least one contained in the ring-type organosilane ester of unsaturated bond.The injection rate of electrolyte is generally 1.5-4.9 gram/ampere-hour, and the concentration of electrolyte is generally 0.1-2.0 rubs/liter.
In more detail the present invention will be described by embodiment below.
The various raw materials used in embodiment are the various raw materials that this area routine uses, all can by commercially available.
Embodiment 1
The present embodiment is for illustration of cathode size of the present invention and lithium ion battery negative and lithium ion battery.
(1) cathode size of lithium ion battery is prepared
Get graphite 100 weight portion, deionized water 130 weight portion, carbon black 2 weight portion, carboxymethyl cellulose (CMC) 2 weight portion, butadiene-styrene rubber (SBR) 4 weight portion, pore creating material Celogen Az (particle diameter 0.5 ~ 2.5um, decomposition temperature 110 DEG C, after decomposing, residual ash is not higher than 0.2%) 3 weight portions.
First CMC and deionized water are stirred under vacuum degree is less than the condition of-0.08MPa and obtain the CMC aqueous solution in 3 hours, then carbon black, SBR, graphite, pore creating material are added in the CMC aqueous solution, fully stir 7 hours be less than the condition of-0.08MPa in vacuum degree under, obtain cathode size.
(2) negative pole of lithium ion battery is prepared
Cathode size obtained above is coated in the copper foil surface that thickness is 12um equably, then the Copper Foil having applied slurry is dried moisture at 95 DEG C.Then roll pole piece, rolling velocity is 15m/min.Finally heat-treat pole piece, the vacuum degree of heat-treat condition is less than-0.08MPa, and temperature is 140 DEG C, and baking time is 15min, and obtaining thickness is 120um, and compacted density is 1.32g/cm
3, porosity is the cathode pole piece of 40.48%, finally cuts into slices, and obtains the anode plate for lithium ionic cell sample S1 of length × wide × thick=491mm × 43.5mm × 120 μm.
(3) lithium ion cell positive is prepared
Take LiFePO4 (LiFePO
4) 1.5kg, and conductive black (CB), polyvinylidene fluoride (PVDF), 1-METHYLPYRROLIDONE (NMP) is according to weight ratio LiFePO
4: CB:PVDF:NMP=100:5:3.5:110 prepares anode sizing agent, be coated on 12 μm of thick aluminium foils after stirring, then 100 DEG C of dryings 10 minutes, then use tabletting machine, finally cut into slices, obtain the based lithium-ion battery positive plate of length × wide × thick=471mm × 42mm × 160um.
(4) lithium ion battery is prepared
The polypropylene screen barrier film of lithium ion battery negative obtained to abovementioned steps (2) and (3), positive pole and thick 25 μm is stacked successively according to the order of positive plate, barrier film, negative plate, then reels, make the pole piece of lithium ion battery.This pole piece is put into the steel square lithium ion battery shell of high 50mm, thick 5mm, wide 34mm, then inject 3.8g electrolyte, finally sealed battery case, makes 053450 lithium ion battery sample S11.Electrolyte is LiPF6/EC+DEC+EMC+DMC system.
Embodiment 2
Preparing cathode size, negative pole, positive pole and lithium ion battery according to the method for embodiment 1, is 2 weight portions unlike the amount of pore creating material in step (1), and obtained cathode size, obtaining thickness is 120um, and compacted density is 1.32g/cm
3, porosity is the cathode pole piece of 38.95%, finally cuts into slices, and obtains the anode plate for lithium ionic cell sample S2 of length × wide × thick=491mm × 43.5mm × 120 μm.All the other steps are all identical, obtained 053450 lithium ion battery S22.
Embodiment 3
Preparing cathode size, negative pole, positive pole and lithium ion battery according to the method for embodiment 1, is 4 weight portions unlike the amount of pore creating material in step (1), and obtained cathode size, obtaining thickness is 120um, and compacted density is 1.32g/cm
3, porosity is the cathode pole piece of 38.80%, finally cuts into slices, and obtains the anode plate for lithium ionic cell sample S3 of length × wide × thick=491mm × 43.5mm × 120 μm.All the other steps are all identical, obtained 053450 lithium ion battery S33.
Embodiment 4
Preparing cathode size, negative pole, positive pole and lithium ion battery according to the method for embodiment 1, is 6 weight portions unlike the amount of pore creating material in step (1), and obtained cathode size, obtaining thickness is 120um, and compacted density is 1.32g/cm
3, porosity is the cathode pole piece of 40.56%, finally cuts into slices, and obtains the anode plate for lithium ionic cell sample S4 of length × wide × thick=491mm × 43.5mm × 120 μm.All the other steps are all identical, obtained 053450 lithium ion battery S44.
Embodiment 5
Preparing cathode size, negative pole, positive pole and lithium ion battery according to the method for embodiment 1, is 0.2 ~ 1um unlike the particle diameter of pore creating material in step (1), and obtained cathode size, obtaining thickness is 120um, and compacted density is 1.32g/cm
3, porosity is the cathode pole piece of 38.58%, finally cuts into slices, and obtains the anode plate for lithium ionic cell sample S5 of length × wide × thick=491mm × 43.5mm × 120 μm.All the other steps are all identical, obtained 053450 lithium ion battery S55.
Embodiment 6
Preparing cathode size, negative pole, positive pole and lithium ion battery according to the method for embodiment 1, is 2.5 ~ 4um unlike the particle diameter of pore creating material in step (1), and obtained cathode size, obtaining thickness is 120um, and compacted density is 1.32g/cm
3, porosity is the cathode pole piece of 38.37%, finally cuts into slices, and obtains the anode plate for lithium ionic cell sample S6 of length × wide × thick=491mm × 43.5mm × 120 μm.All the other steps are all identical, obtained 053450 lithium ion battery S66.
Embodiment 7
Preparing cathode size, negative pole, positive pole and lithium ion battery according to the method for embodiment 1, is unifor unlike pore creating material in step (1), obtained cathode size, and heat treatment temperature is 150 DEG C, and to obtain thickness be 120um, and compacted density is 1.32g/cm
3, porosity is the cathode pole piece of 37.76%, finally cuts into slices, and obtains the anode plate for lithium ionic cell sample S7 of length × wide × thick=491mm × 43.5mm × 120 μm.All the other steps are all identical, obtained 053450 lithium ion battery S77.
Embodiment 8
Cathode size, negative pole, positive pole and lithium ion battery is prepared according to the method for embodiment 1, be 4,4'-disulfonyl hydrazide diphenyl ether unlike pore creating material in step (1), obtained cathode size, in step (2), heat treated temperature is 160 DEG C to obtain thickness is 120um, and compacted density is 1.32g/cm
3, porosity is the cathode pole piece of 36.95%, finally cuts into slices, and obtains the anode plate for lithium ionic cell sample S8 of length × wide × thick=491mm × 43.5mm × 120 μm.All the other steps are all identical, obtained 053450 lithium ion battery S88.
Comparative example 1
Identically with the method for embodiment 1 prepare cathode size, negative pole, positive pole and lithium ion battery, unlike
(1) preparation of cathode size
Get graphite 100 weight portion, deionized water 130 weight portion, carbon black 2 weight portion, carboxymethyl cellulose (CMC) 2 weight portion, butadiene-styrene rubber (SBR) 4 weight portion, pore creating material polymer poly alkylsiloxane 3 weight portion.
First CMC and deionized water are stirred under vacuum degree is less than the condition of-0.08MPa and obtain the CMC aqueous solution in 3 hours, then carbon black, SBR, graphite, pore creating material are added in the CMC aqueous solution, fully stir 7 hours be less than the condition of-0.08MPa in vacuum degree under, obtain cathode size.
(2) negative pole of lithium ion battery is prepared
Cathode size obtained above is coated in the copper foil surface that thickness is 12um equably, then the Copper Foil having applied slurry is dried moisture at 95 DEG C.Then roll pole piece, rolling velocity is 15m/min, and obtaining thickness is 120um, and compacted density is 1.32g/cm
3cathode pole piece, finally cut into slices, obtain the anode plate for lithium ionic cell of length × wide × thick=491mm × 43.5mm × 120 μm, all the other steps are all identical, and obtained 053450 lithium ion battery DS11, battery standing disassembles to obtain cathode pole piece sample DS1 after 1 day.
Comparative example 2
Identically with the method for embodiment 1 prepare cathode size, negative pole, positive pole and lithium ion battery, unlike:
(1) pore creating material Celogen Az is not added in the preparation of cathode size.
(2) prepare in the negative pole of lithium ion battery and do not heat-treat after negative plate calendering, direct slicing, obtain the anode plate for lithium ionic cell DS2 of length × wide × thick=491mm × 43.5mm × 120 μm, all the other steps are all identical, obtained 053450 lithium ion battery DS22.
Performance Detection:
(1) cathode pole piece porosity detects: the full-automatic mercury injection apparatus of AutoporeIV9500 using Merck & Co., Inc of the U.S. to produce tests the open-cell porosity of cathode pole piece sample S1-S8 prepared by above-described embodiment 1-8, maximum pressure is the porosity of the cathode pole piece sample DS2 leaving standstill the cathode pole piece sample DS1 after disassembling for 1 day and comparative example 2 preparation after 30000PSI and same procedure test comparison example 1 are assembled into battery, and test result is in table 1.
(2) capacity after battery partial volume:
The forming and capacity dividing system of battery is: 0.02C charges 8h, 0.2C constant-current constant-voltage charging to 3.6V, cut-off current 20mA; Shelve 10min; 0.5C discharges into 2.0V; Shelve 10min, 0.2C constant current constant voltage to 3.6V, cut-off current 0.02C; Shelve 10min; 0.2C discharges into 2.0V, record discharge capacity.The results are shown in Table 1.
Table 1
| Cathode pole piece | Porosity/% | Battery | Capacity/mAh |
| S1 | 40.48 | S11 | 650 |
| S2 | 38.95 | S22 | 646 |
| S3 | 38.80 | S33 | 645 |
| S4 | 40.56 | S44 | 636 |
| S5 | 38.58 | S55 | 638 |
| S6 | 38.37 | S66 | 639 |
| S7 | 37.76 | S77 | 637 |
| S8 | 36.95 | S88 | 633 |
| DS1 | 30.47 | DS11 | 630 |
| DS2 | 28.85 | DS22 | 625 |
The porosity of cathode pole piece prepared by embodiments of the invention is high, substantially be more than 36%, and pore-creating after calendering, the pore size distribution of pole piece is even, particularly there is not closed pore in top layer, and pore structure is abundanter, and the capacity of battery prepared by the present invention is higher, may due to the raising of open-cell porosity, the formation of SEI film is more fully with stable.
Battery low temperature high rate performance test under (3)-20 DEG C of conditions:
Battery S11-S88 and DS11-DS22 under-20 DEG C of conditions prepared by embodiment 1-8 and comparative example 1-2 respectively with 0.2C, 1C, 2C constant current charge to 3.8V, rear 0.5C is discharged to 1.5V, record charging capacity, press in charging, test result is in table 2.
Table 2
Wherein, when DS22 battery is with 1C current charges, middle pressure is 3.725V, after charging complete, normal temperature shelf 24 hours, 0.5C discharge platform 3.4V, far above this battery partial volume platform at normal temperatures (the discharge platform 3.241V of 0.5C), normal temperature capacity restoration is 120mAh, dissects discovery and analyses lithium, illustrate that battery damages.
Battery S11-S88 and DS11-DS22 under-20 DEG C of conditions prepared by embodiment 1-8 and comparative example 1-2 respectively with 0.5C constant-current constant-voltage charging to 3.8V, cut-off current 20mA, rear respectively with 0.2C, 1C, 2C constant-current discharge 1.5V, record discharge capacity, press in electric discharge, test result is in table 3.
Table 3
(4) normal temperature battery high rate performance test:
Battery S11-S88 and DS11-DS22 at 25 DEG C prepared by embodiment 1-8 and comparative example 1-2 respectively with 0.2C, 1C, 5C, 10C constant current charge to 3.6V, rear 0.5C is discharged to 2.0V, record charging capacity, press in charging, test result is in table 4.
Table 4
Wherein, DS11, DS22 with during 10C current charges without platform (middle pressure), voltage directly rises to cut-ff voltage, now in pressure without contrast meaning, charging curve is shown in Fig. 1, Fig. 2.
Battery S11-S88 and DS11-DS22 under 25 DEG C of conditions prepared by embodiment 1-8 and comparative example 1-2 respectively with 0.5C constant-current constant-voltage charging to 3.6V, cut-off current 20mA, rear respectively with 0.2C, 1C, 5C, 10C constant-current discharge 2.0V, record discharge capacity, press in electric discharge, test result is in table 5.
Table 5
As can be seen from test result, battery capacity prepared by cathode pole piece of the present invention is high, and low temperature, normal temperature high rate performance are excellent.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.
Claims (13)
1. a lithium ion battery negative, it is characterized in that, described negative pole is coated on negative electrode collector by cathode size, drying, calendering, heat treatment prepare, the porosity of described negative pole is 20 ~ 50%, described cathode size comprises negative active core-shell material, binding agent, solvent and pore creating material, and described pore creating material is selected from one or more in azo-compound and/or sulfonyl hydrazines compound; Described negative active core-shell material is native graphite, one or more in Delanium or hard charcoal, and described cathode size also comprises conductive agent and/or thickener; The mean particle size of described pore creating material is 0.2 ~ 4um.
2. negative pole according to claim 1, is characterized in that, described pore creating material be selected from Celogen Az, unifor or 4,4'-disulfonyl hydrazide diphenyl ether one or more.
3. negative pole according to claim 1, is characterized in that, the mean particle size of described pore creating material is 0.5 ~ 2.5um.
4. negative pole according to claim 1, is characterized in that, the decomposition temperature of described pore creating material is 105 ~ 150 DEG C, and after decomposing, residual ash is not higher than 0.5%.
5. negative pole according to claim 1, is characterized in that, relative to the negative active core-shell material of 100 weight portions, the content of described pore creating material is 1 ~ 6 weight portion.
6. negative pole according to claim 5, is characterized in that, relative to the negative active core-shell material of 100 weight portions, the content of described pore creating material is 2 ~ 4 weight portions.
7. negative pole according to claim 1, is characterized in that, described solvent is water; Described binding agent is water-based binder.
8. negative pole according to claim 7, is characterized in that, described water-based binder is selected from one or more in polyvinyl fluoride, polyvinyl chloride or butadiene-styrene rubber.
9. negative pole according to claim 1, is characterized in that, described heat treated vacuum degree is less than-0.08MPa, and described heat treated temperature is 110 ~ 160 DEG C.
10. negative pole according to claim 1, is characterized in that, the described heat treated time is 10 ~ 25min.
11. negative poles according to claim 1, is characterized in that, the temperature of described drying is 80 ~ 105 DEG C, and the speed of described calendering is 10 ~ 20m/min.
12. negative poles according to claim 1, is characterized in that, the compacted density of described negative pole is 1.20 ~ 1.45g/cm3.
13. 1 kinds of lithium ion batteries, is characterized in that, comprise battery container and the electrode group be sealed in this battery container and electrolyte; Described electrode group comprises positive pole, negative pole and the barrier film between positive pole and negative pole, and wherein, described negative pole is the lithium ion battery negative described in claim 10-12 any one.
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| CN105336917B (en) * | 2014-08-14 | 2018-11-20 | 东莞新能源科技有限公司 | The preparation method of lithium ion battery and its negative electrode tab |
| CN105742569B (en) * | 2016-04-07 | 2018-08-03 | 湖南杉杉能源科技股份有限公司 | A kind of lithium ion battery negative electrode and preparation method thereof |
| CN105762366A (en) * | 2016-05-04 | 2016-07-13 | 江苏深苏电子科技有限公司 | Composite current collector of lithium ion battery and manufacturing method of composite current collector |
| CN107749459B (en) * | 2016-11-07 | 2020-11-03 | 万向一二三股份公司 | Preparation method of lithium manganate battery cathode |
| CN108539265A (en) * | 2017-03-02 | 2018-09-14 | 深圳格林德能源有限公司 | A kind of lithium-sulfur cell |
| CN108767195B (en) * | 2018-04-27 | 2021-01-26 | 国联汽车动力电池研究院有限责任公司 | Silicon-based electrode with adjustable pore structure and preparation method thereof |
| CN109659493B (en) * | 2018-12-26 | 2021-03-23 | 国联汽车动力电池研究院有限责任公司 | Low-porosity negative electrode containing solid electrolyte and lithium battery applying negative electrode |
| CN109830748B (en) * | 2019-01-22 | 2021-09-24 | 东莞市天丰电源材料有限公司 | Lithium ion battery electrolyte |
| CN109888290B (en) * | 2019-03-19 | 2021-01-22 | 郑州中科新兴产业技术研究院 | High-rate lithium ion battery, aging and formation method |
| CN112417725A (en) * | 2020-11-20 | 2021-02-26 | 苏州凌威新能源科技有限公司 | Design method for porosity of negative plate |
| CN112614966B (en) * | 2020-12-11 | 2022-04-19 | 联动天翼新能源有限公司 | Preparation method of porous silicon negative plate, porous silicon negative plate and lithium battery |
| CN112467225B (en) * | 2020-12-17 | 2022-04-26 | 湖南美尼科技有限公司 | Preparation method of high-rate battery |
| CN112701244A (en) * | 2020-12-25 | 2021-04-23 | 东莞塔菲尔新能源科技有限公司 | Safety liquid, preparation method thereof, material with safety coating and application |
| CN113422005B (en) * | 2021-06-23 | 2022-04-15 | 天目湖先进储能技术研究院有限公司 | Porous electrode, preparation method thereof and lithium battery |
| CN115295764A (en) * | 2022-07-29 | 2022-11-04 | 江苏正力新能电池技术有限公司 | Negative pole piece, preparation method thereof and secondary battery |
| CN115377353A (en) * | 2022-10-27 | 2022-11-22 | 中创新航科技股份有限公司 | Negative plate and battery using same |
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