CN111640907B - Lithium ion battery anode slurry, preparation method thereof and stirring cylinder used in preparation process - Google Patents

Lithium ion battery anode slurry, preparation method thereof and stirring cylinder used in preparation process Download PDF

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CN111640907B
CN111640907B CN202010476469.8A CN202010476469A CN111640907B CN 111640907 B CN111640907 B CN 111640907B CN 202010476469 A CN202010476469 A CN 202010476469A CN 111640907 B CN111640907 B CN 111640907B
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stirring
solvent
stirring cylinder
added
ion battery
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CN111640907A (en
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方杰雄
杜双龙
吕正中
刘金成
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Eve Energy Co Ltd
Hubei Eve Power Co Ltd
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Eve Energy Co Ltd
Hubei Eve Power Co Ltd
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/50—Mixing liquids with solids
    • B01F23/51—Methods thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F23/00—Mixing according to the phases to be mixed, e.g. dispersing or emulsifying
    • B01F23/50—Mixing liquids with solids
    • B01F23/53—Mixing liquids with solids using driven stirrers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F29/00—Mixers with rotating receptacles
    • B01F29/80—Mixers with rotating receptacles rotating about a substantially vertical axis
    • B01F29/83—Mixers with rotating receptacles rotating about a substantially vertical axis with rotary paddles or arms, e.g. movable out of the receptacle
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • 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 stirring cylinder used in a preparation method and a preparation process of lithium ion battery positive electrode slurry, wherein the preparation method of the lithium ion battery positive electrode slurry comprises the steps of adding active substance powder into a mixer together with solvent, adding the solvent in a spraying mode, continuously soaking and sinking the active substance powder to the bottom of the mixer in the mixing process, reducing the active substance powder floating or sticking on the inner wall of the mixer and a stirring paddle, strengthening the soaking of the active substance powder, avoiding the formation of thick wet layers on the inner wall of the mixer and the stirring paddle, reducing the problem of unbalanced proportion of the positive electrode slurry caused by the formation of the wet layers, being beneficial to improving the mixing uniformity of the positive electrode slurry, reducing the number of times of discharging and blocking the positive electrode slurry in the later period, and having short preparation process time.

Description

Lithium ion battery anode slurry, preparation method thereof and stirring cylinder used in preparation process
Technical Field
The invention belongs to the field of lithium batteries, and relates to a lithium ion battery anode slurry, a preparation method thereof and a stirring cylinder used in the preparation process.
Background
The key of the development of new energy automobiles is the power supply of the new energy automobiles. The lithium ion battery has the advantages of high energy density, small self-discharge, no memory effect, wide working voltage range, long service life, no environmental pollution and the like, and is a main power supply of the current new energy automobile. Wherein the performance of the positive electrode slurry has an important influence on the performance of the lithium ion battery.
CN106129336a discloses a preparation method of lithium battery positive electrode slurry, which comprises the following steps: (1) Adding a solvent into a reactor, uniformly spraying a dry product of the binder A on the surface of the solvent, and stirring and dispersing; (2) Then adding the dry product of the adhesive B into the reactor, and stirring and dispersing; (3) Then adding the auxiliary material dry product into the reactor, stirring and dispersing; (4) Then adding the positive electrode powder dry product into the reactor, stirring and dispersing to obtain slurry; and (5) passing the slurry through a colloid mill, cooling, and adjusting the viscosity. CN109524616a discloses a lithium ion battery positive electrode slurry and a preparation method thereof, wherein the preparation method comprises the following steps: (1) Adding the glue solution into the conductive paste, and uniformly mixing to obtain composite paste; the glue solution comprises a binder and a solvent; the conductive paste includes a conductive agent and a dispersant; (2) Adding part of positive electrode active material into the obtained composite slurry, and uniformly mixing to obtain primary positive electrode slurry; (3) And adding the residual anode active material into the primary anode slurry, and uniformly mixing to obtain the anode slurry of the lithium ion battery. CN108767191a discloses a preparation method of positive electrode slurry of a lithium ion battery, which comprises the following steps: (1) Stirring the positive electrode active material, the binder, the first conductive agent and the additive in proportion for 10-25 min by using a planetary vacuum stirrer at revolution speed of 20+ -5 rpm and rotation speed of 1000+ -50 rpm, so that the temperature is controlled at 20-35 ℃; (2) Adding the solvent according to the proportion, and stirring for 60-100 min at revolution speed of 20+ -5 rpm and rotation speed of 1200+ -50 rpm; (3) Adding the second conductive agent according to the proportion, stirring for 100-140 min at revolution speed of 20+ -5 rpm and autorotation speed of 1300+ -50 rpm, and carrying out vacuum defoaming, wherein the vacuum degree is-0.08 to-0.1 MPa; in the preparation process of the positive electrode slurry, powder is easy to form a wet layer on the inner wall of the stirring cylinder and the stirring paddle, so that the proportion imbalance of the positive electrode slurry is easy to cause.
At present, the preparation process of the positive electrode slurry of the lithium iron phosphate power lithium ion battery mainly comprises the steps of adding one material into a stirring cylinder. Such a sequence of addition has some drawbacks: firstly, after a large amount of solvent and powder are added into a 1500L stirring cylinder, layering between the solvent and the powder is obvious, the powder floats on the upper layer of the solvent, and the upper layer of powder floats or is adhered to the inner wall of the stirring cylinder and the upper layer of a stirring paddle, so that insufficient stirring is realized; secondly, the wet material layer with larger thickness, which is easily formed on the inner wall of the stirring cylinder and the upper layer of the stirring paddle, is caused by insufficient stirring, the cylinder is scraped manually, the dry powder is wrapped by the external wet material layer, the filter screen is blocked along with the discharge of the slurry, and the production efficiency is affected; third, the feeding sequence of one item requires about 8 hours from feeding to discharging, which takes a long time and increases the manufacturing cost.
Therefore, development of a preparation method of the lithium ion battery anode slurry capable of effectively improving the mixing uniformity of the lithium ion battery anode slurry is still significant.
Disclosure of Invention
The invention aims to provide a stirring cylinder used in a preparation method and a preparation process of lithium ion battery positive electrode slurry, wherein the preparation method of the lithium ion battery positive electrode slurry comprises the steps that during the process of adding active substance powder into a mixer, a solvent is added in a spraying mode, the active substance powder is continuously infiltrated and sunk to the bottom of the mixer in the mixing process, active substance powder floating or on the inner wall of the mixer and a stirring paddle is reduced, meanwhile, the infiltration of the active substance powder is enhanced, thick wet layers are prevented from being formed on the inner wall of the mixer and the stirring paddle, the problem of unbalanced proportion of the positive electrode slurry caused by the formation of the wet layers is solved, the improvement of the mixing uniformity of the positive electrode slurry is facilitated, the discharging blocking frequency of the post-stage positive electrode slurry is reduced, and the preparation process is short in time consumption.
In order to achieve the aim of the invention, the invention adopts the following technical scheme:
in a first aspect, the invention provides a method for preparing a lithium ion battery positive electrode slurry, which comprises the steps of adding a solvent in a spraying manner during the process of adding active material powder into a mixer.
The preparation process of the lithium ion battery anode slurry adopts the addition of the solvent in the process of adding the active material powder, and the solvent is added in a spraying mode, so that the infiltration of the active material powder is facilitated, the formation of wet layers in a mixer and on a stirring paddle is reduced, the problem of unbalanced anode slurry proportion caused by the formation of the wet layers is avoided, and the uniformity of slurry mixing is improved; the time required for preparing the anode slurry by the method can be shortened by 20 percent compared with that of the anode slurry prepared by the traditional preparation method.
Preferably, the solvent is sprayed at a rate of 0.2 to 0.22Kg/s, for example 0.205Kg/s, 0.21Kg/s or 0.215Kg/s, etc.
Preferably, the active material powder is added at a rate of 0.3 to 0.35Kg/s, for example 0.31Kg/s, 0.32Kg/s, 0.33Kg/s or 0.34Kg/s, etc.
The rate of charging is controlled in the range in the preparation process of the lithium ion battery anode slurry, so that the infiltration of active material powder is promoted, a wet material layer is prevented from being formed on the inner wall of a mixer and a stirring paddle, the controllability of the slurry preparation process is improved, and the imbalance of slurry proportion caused by stirring is avoided.
Preferably, the preparation method of the lithium ion battery anode slurry comprises the following steps:
(1) Adding active material powder into a mixer, wherein the addition process of the active material powder is accompanied by the addition of conductive carbon black and the addition of a solvent, and the addition of the solvent is carried out in a spraying mode;
(2) Adding active material powder into a mixer in the step (1), wherein the adding process of the active material powder is accompanied by adding conductive paste, and mixing, wherein the conductive paste is added in a spray mode;
(3) Spraying and adding a solvent into the product obtained in the step (2), and mixing;
(4) And (3) adding glue solution into the product of the step (3), and mixing to obtain the lithium ion battery anode slurry.
In the mixing process of the lithium ion battery anode slurry, the active material powder is added into the mixer along with the addition of the conductive carbon black and the solvent, and the solvent is added in a spraying mode in the process, so that the wettability of the active material can be obviously improved, and the active material powder is prevented from being adhered to the inner wall of the mixer or a stirring paddle to form a wet layer; then adding active material powder, wherein the conductive paste is added in a spraying mode along with the addition of the conductive paste in the adding process, and further spraying powder and a wet material layer which are adhered to the inner wall of the mixer and the stirring paddle, so that the mixing efficiency is improved, and the mixing time is saved.
Preferably, the ratio of the amount of active material powder added in step (1) to the amount of active material powder added in step (2) is (4-6): (4-6), such as 4.5:5.5, 5:5 or 5.5:4.5, etc.
In the preparation method, active substance powder is added in two times, a part of powder is firstly wetted and stirred, the powder is dispersed in advance, and the condition that excessive powder is added at one time and the stirring cylinder is not accommodated is avoided.
Preferably, the ratio of the amount of solvent added in step (1) to the amount of solvent added in step (3) is (8-9): (2-1), e.g. 8:2, 8.5:1.5 or 9:1, etc.
Preferably, the solvent of step (1) is sprayed onto the inner wall of the mixer during spraying.
Preferably, the active material powder includes at least one of lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium cobalt oxide and lithium manganese oxide.
Preferably, the particle size of the active material powder is 0.3 to 10 μm, for example 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm or 9 μm, etc., preferably 0.6 to 1.6 μm.
Preferably, the solvent comprises N-methylpyrrolidone and/or absolute ethanol.
Preferably, the conductive carbon black of step (1) comprises a conductive carbon black SP, preferably a conductive carbon black SP having a particle size of 8-800nm, e.g., 10nm, 50nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm or 700nm, etc.
Preferably, the mixer is a stirred tank.
The stirring tank is a closed stirring tank, such as a Ross stirring tank.
Preferably, the mixing in step (1) is carried out by revolving a stirring cylinder at a revolution rate of 9-11rpm, such as 9.5rpm, 10rpm or 10.5 rpm.
In the mixing process in the step (1), only the stirring cylinder is revolved, and the revolution speed is limited within the range, so that the powder is uniformly and macroscopically stirred, and the dispersion is not required to be started.
Preferably, after the material is added in step (1), the mixing is continued for 50-70min, such as 52min, 55min, 58min, 60min, 62min, 65min or 68 min.
Preferably, the solvent spray rate in step (1) is 0.2-0.22Kg/s, e.g. 0.205Kg/s, 0.21Kg/s or 0.215Kg/s, etc.
Preferably, the conductive paste of step (2) comprises a carbon nanotube conductive paste; carbon nanotube slurries having a solids content of 4-6% are preferred.
The solvent of the conductive paste herein may be selected from NMP.
Preferably, the spraying rate of the conductive paste in the step (2) is 0.1 to 0.12Kg/s, for example, 0.105Kg/s, 0.11Kg/s, 0.115Kg/s, or the like.
Preferably, during the addition of the active material powder and the electroconductive paste in step (2), the revolution rate of the stirring vessel is 14 to 16rpm, for example 14.5rpm, 15rpm, 15.5rpm or the like, and the stirring rate of the stirring vessel is 450 to 550rpm, for example 480rpm, 500rpm, 520rpm, 540rpm or the like.
The revolution rate and stirring rate of the stirring cylinder in the step (2) are defined in the above ranges, which are favorable for uniformly mixing the materials and are in the range of the load capacity of the equipment. Below this range, stirring is uneven, and slurry is not well dispersed; the equipment beyond the range is overloaded and worn greatly, and the use of the equipment is affected.
Preferably, after the addition of the materials in step (2) is completed, the mixing is continued for 80-100min, for example, 85min, 90min or 95 min.
Preferably, the solvent spray rate in step (3) is 0.2-0.22Kg/s, e.g., 0.205Kg/s, 0.21Kg/s, or 0.215Kg/s, etc.
Preferably, the solvent in step (3) is sprayed onto the inner wall of the mixer during spraying.
Preferably, during the spraying of the solvent in step (3), the revolution rate of the stirring cylinder is 19-21rpm, such as 19.5rpm, 20rpm, or 20.5rpm, etc., and the stirring rate is 950-1050rpm, such as 980rpm, 1000rpm, 1020rpm, etc.
The revolution rate and the stirring rate of the stirring cylinder in the step (3) are defined in the range, and the materials can be uniformly mixed within the load capacity range of the equipment. Below this range, stirring is uneven, and slurry is not well dispersed; the equipment beyond the range is overloaded and worn greatly, and the use of the equipment is affected.
Preferably, after the spraying in step (3) is finished, the mixing is continued for 50-70min, such as 55min, 60min or 65 min.
Preferably, the glue solution in the step (4) is a mixed solution of polyvinylidene fluoride and N-methyl pyrrolidone.
Preferably, the solids content of the dope of step (4) is 6-10%, e.g. 6.5%, 7%, 7.5%, 8%, 8.5%, 9% or 9.5%, etc.
Preferably, during the addition of the glue solution in step (4), the revolution rate of the stirring cylinder is 24-26rpm, such as 24.5rpm, 25rpm or 25.5rpm, etc., and the stirring rate is 1150-1250rpm, such as 1160rpm, 1180rpm, 1200rpm, 1220rpm or 1240rpm, etc.
The revolution rate and the stirring rate of the stirring cylinder in the step (4) are defined in the range, and the materials can be uniformly mixed within the load capacity range of the equipment. Below this range, stirring is uneven, and slurry is not well dispersed; the equipment beyond the range is overloaded and worn greatly, and the use of the equipment is affected.
Preferably, the vacuum degree is less than or equal to-0.085 MPa in the process of adding the glue solution in the step (4).
Preferably, the temperature during the addition of the glue in step (4) is 22-28 ℃, e.g. 23 ℃, 24 ℃, 25 ℃, 26 ℃ or 27 ℃, etc.
Preferably, after the glue solution is added in the step (4), the mixing is continued for 110-130min, for example 115min, 120min or 125 min.
Preferably, the preparation method of the glue solution in the step (4) comprises adding N-methylpyrrolidone and polyvinylidene fluoride powder into a stirring tank for mixing, wherein the revolution speed of the stirring tank is 24-26rpm, such as 24.5rpm, 25rpm or 25.5rpm, and the like, the stirring speed is 1950-2050rpm, such as 1980rpm, 2000rpm, 2030rpm, and the like, and the mixing time is 240-480min, such as 280min, 300min, 320min, 340min, 360min, 380min, 400min, 420min, 440min or 460min, and the like.
Preferably, the step (4) further comprises adjusting the viscosity after the mixing is completed.
Preferably, in the process of adjusting the viscosity in the step (4), the revolution rate of the stirring cylinder is 9-11rpm, for example 9.5rpm, 10rpm or 10.5rpm, etc., and the stirring rate is 950-1050rpm, for example 980rpm, 1000rpm or 1020rpm, etc., and the vacuum degree is less than or equal to-0.085 MPa.
Preferably, the temperature of the viscosity adjustment process is 22-28deg.C, such as 23deg.C, 24deg.C, 25deg.C, 26deg.C or 27deg.C, etc.
Preferably, the viscosity is adjusted in step (4) by adding a solvent.
Testing viscosity after stirring, and adding solvent for stirring and adjusting if the viscosity exceeds a required viscosity range; if the viscosity is within the desired range, no solvent is added to adjust the viscosity.
As a preferable technical scheme of the invention, the preparation method of the lithium ion battery anode slurry comprises the following steps:
adding lithium iron phosphate powder into a stirring cylinder with the revolution speed of 9-11rpm, wherein the addition process of the lithium iron phosphate powder is accompanied by the addition of conductive carbon black SP and N-methyl pyrrolidone, the N-methyl pyrrolidone is added in a spraying mode, and the stirring cylinder continues to revolve for 50-70min after the material is added;
(II) regulating the revolution speed of the stirring cylinder to be 14-16rpm, regulating the stirring speed to be 450-550rpm, adding lithium iron phosphate powder into the stirring cylinder, wherein the adding process of the lithium iron phosphate powder is accompanied with the adding of conductive paste of the carbon nano tubes, the conductive paste of the carbon nano tubes is added in a spraying mode, and the continuous revolution and stirring time of the stirring cylinder is 80-100min after the material is added;
(III) regulating the revolution speed of the stirring cylinder to be 19-21rpm, regulating the stirring speed to be 950-1050rpm, spraying N-methyl pyrrolidone into the product of the step (II), spraying N-methyl pyrrolidone on the inner wall of the stirring cylinder in the spraying process, and continuously revolving and stirring the stirring cylinder for 50-70min after the materials are added;
(IV) regulating the revolution speed of the stirring cylinder to 24-26rpm, regulating the stirring speed to 1150-1250rpm, regulating the vacuum degree to less than or equal to-0.085 MPa, adding the glue solution into the product of the step (III), and continuously revolving and stirring the stirring cylinder for 110-130min after the materials are added;
(V) regulating the revolution speed of the stirring cylinder to 9-11rpm, stirring the lithium ion battery at 950-1050rpm, and keeping the vacuum degree less than or equal to-0.085 MPa for 0-60min to obtain the lithium ion battery anode slurry.
The viscosity can be adjusted here in step (V) by adding solvents.
Preferably, the lithium ion battery positive electrode slurry comprises the following components in percentage by mass based on 100% of the lithium ion battery positive electrode slurry:
Figure BDA0002515992390000081
based on the mass of the lithium ion battery positive electrode slurry being 100%, the lithium ion battery positive electrode slurry comprises the following components in percentage by mass: the mass percentage of the active material powder is 50-56%, such as 50.5%, 51.5%, 52%, 52.5%, 53%, 53.5%, 54%, 54.5%, 55%, 55.5%, etc., the mass percentage of the conductive carbon black is 0.2-0.4%, such as 0.25%, 0.3%, 0.35%, etc., the mass percentage of the conductive paste is 7-9%, such as 7.5%, 8%, 8.5%, etc., the mass percentage of the glue solution is 12-16%, such as 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 15.5%, etc., and the mass percentage of the solvent is 20-25%, such as 20.5%, 21%, 21.5%, 22%, 22.5%, 23%, 23.5%, 24%, 24.5%, etc.
In a second aspect, the present invention provides a lithium ion battery positive electrode slurry prepared by the method according to the first aspect, wherein the viscosity of the lithium ion battery positive electrode slurry is 10000-25000 mPa-s, such as 11000 mPa-s, 13000 mPa-s, 15000 mPa-s, 18000 mPa-s, 20000 mPa-s, 22000 mPa-s, 24000 mPa-s, etc.
The invention limits the viscosity of the positive electrode slurry of the lithium ion battery in the range, is beneficial to the coating process, has stable coating surface density and small abrasion to a coating machine head.
Preferably, the fineness of the lithium ion battery positive electrode slurry is 4 to 8 μm, for example, 5 μm, 6 μm, 7 μm, or the like.
In a third aspect, the present invention provides a stirring tank used in the method for preparing a lithium ion battery positive electrode slurry according to the first aspect, wherein the stirring tank is provided with an active material powder inlet, a conductive slurry inlet, a conductive carbon black inlet, a solvent inlet and a glue solution inlet, respectively.
The stirring tank can be additionally provided with the inlet on the basis of a traditional Ross stirring tank.
Compared with the prior art, the invention has the following beneficial effects:
(1) According to the preparation method of the lithium ion battery anode slurry, the active material powder is added along with the addition of the solvent in the process of adding the active material powder into the mixer, and meanwhile, the solvent is added in a spraying mode, so that the wettability of the active material powder can be obviously improved, a wet material layer is prevented from being formed on the inner wall of the mixing device and the stirring paddle in the mixing process, and the problem of unbalanced slurry proportion caused by the formation of the wet material layer of the anode slurry is avoided;
(2) According to the preparation method of the lithium ion battery anode slurry, the solvent and the active material powder are mixed in a spraying mode, so that the wettability of the powder can be effectively enhanced, the mixing efficiency is optimized, and the time required for preparing the slurry is reduced.
Drawings
FIG. 1 is a schematic diagram of a pipeline structure of a stirring cylinder used in a preparation method of lithium ion battery anode slurry;
1-active material powder inlet, 2-conductive paste inlet, 3-conductive carbon black inlet, 4-solvent inlet and 5-glue inlet.
Detailed Description
The technical scheme of the invention is further described by the following specific embodiments. It will be apparent to those skilled in the art that the examples are merely to aid in understanding the invention and are not to be construed as a specific limitation thereof.
The pipe structure of the stirring cylinder adopted in the preparation method of the lithium ion battery anode slurry is shown in figure 1, and as can be seen from figure 1, the upper end of the stirring cylinder is respectively provided with an active substance powder inlet 1, a conductive slurry inlet 2, a conductive carbon black inlet 3, a solvent inlet 4 and a glue solution inlet 5.
The stirring cylinder is additionally provided with the 5 adding ports on the basis of a traditional Ross stirring cylinder, so that all components of the positive electrode slurry of the lithium ion battery are added simultaneously.
The apparatus shown in fig. 1 was used in the preparation of the positive electrode slurry for lithium ion batteries in the following examples.
Example 1
The raw material ratio of the lithium ion battery anode slurry is prepared in the embodiment; the lithium ion battery positive electrode slurry comprises the following components in percentage by mass as 100 percent:
Figure BDA0002515992390000101
the glue solution is a mixed solution of N-methyl pyrrolidone and polyvinylidene fluoride, and the solid content of the glue solution is 8%.
The average particle diameter of the lithium iron phosphate powder is 1.1 μm, and the average particle diameter of the conductive carbon black SP is 10nm.
The preparation method of the glue solution comprises the following steps: and sequentially adding N-methylpyrrolidone and polyvinylidene fluoride into a stirring tank, and mixing for 360min under the conditions that the revolution speed is 25rpm and the stirring dispersion speed is 2000rpm to obtain the glue solution.
The preparation method of the lithium ion battery anode slurry in the embodiment comprises the following steps:
adding 50wt% of lithium iron phosphate powder, 100wt% of conductive carbon black SP and 85wt% of N-methyl pyrrolidone in a formula into a 1500L Ross stirring cylinder with revolution speed of 10rpm simultaneously and automatically, wherein the N-methyl pyrrolidone is added in a spraying mode, and the stirring cylinder continuously revolves for 60min after the materials are added; the spraying rate of the N-methyl pyrrolidone is 0.2Kg/s;
(II) regulating the revolution speed of the stirring cylinder to be 15rpm, regulating the stirring speed to be 500rpm, then adding the rest 50wt% of lithium iron phosphate powder and 100wt% of carbon nanotube conductive slurry into the stirring cylinder at the same time, wherein the carbon nanotube conductive slurry is added in a spraying mode, the spraying speed of the carbon nanotube conductive slurry is 0.1Kg/s, and the continuous revolution and stirring time of the stirring cylinder is 90min after the material is added;
(III) regulating the revolution speed of the stirring cylinder to 20rpm, regulating the stirring speed to 1000rpm, spraying and adding the rest 15wt% of N-methyl pyrrolidone into the product obtained in the step (II), wherein the spraying speed is 0.2Kg/s, and continuing to revolve and stir the stirring cylinder for 60min after the material is added;
(IV) regulating the revolution speed of the stirring cylinder to 25rpm, regulating the stirring speed to 1200rpm, regulating the vacuum degree to-0.085 MPa, adding the glue solution into the product of the step (III), and continuously revolving and stirring the stirring cylinder for 120min after the materials are added;
(V) regulating the revolution speed of the stirring cylinder to 10rpm, stirring the lithium ion battery to 1000rpm, and keeping the vacuum degree to-0.085 MPa, wherein the revolution and stirring time of the stirring cylinder is 30min, so as to obtain the lithium ion battery anode slurry.
Example 2
The raw material ratio of the lithium ion battery anode slurry is prepared in the embodiment; the lithium ion battery positive electrode slurry comprises the following components in percentage by mass as 100 percent:
Figure BDA0002515992390000121
the glue solution is a mixed solution of N-methyl pyrrolidone and polyvinylidene fluoride, and the solid content of the mixed solution is 6%.
The average particle diameter of the lithium iron phosphate powder is 1.6 mu m, and the average particle diameter of the conductive carbon black SP is 20nm.
The preparation method of the glue solution comprises the following steps: sequentially adding N-methyl pyrrolidone and polyvinylidene fluoride into a stirring tank, and mixing for 480min under the conditions that the revolution speed is 24rpm and the stirring dispersion speed is 2050rpm to obtain the glue solution.
The preparation method of the lithium ion battery anode slurry in the embodiment comprises the following steps:
adding 40wt% of lithium iron phosphate powder, 100wt% of conductive carbon black SP and 80wt% of N-methyl pyrrolidone in a formula into a 1500L Ross stirring cylinder with a revolution speed of 9rpm simultaneously and automatically, wherein the N-methyl pyrrolidone is added in a spraying mode, the spraying speed is 0.22Kg/s, and after the materials are added, the stirring cylinder continuously revolves for 70min;
(II) regulating the revolution speed of the stirring cylinder to be 16rpm, regulating the stirring speed to be 450rpm, then adding the rest 60wt% of lithium iron phosphate powder and 100wt% of carbon nanotube conductive slurry into the stirring cylinder at the same time, wherein the carbon nanotube conductive slurry is added in a spraying mode, the spraying speed is 0.12Kg/s, and the stirring cylinder continues revolution and stirring for 100min after the materials are added;
(III) regulating the revolution speed of the stirring cylinder to be 19rpm, regulating the stirring speed to be 1050rpm, spraying and adding the rest 20wt% of N-methyl pyrrolidone into the product obtained in the step (II), wherein the spraying speed is 0.22Kg/s, and after the material is added, continuing to revolve and stir for 50min;
and (IV) regulating the revolution speed of the stirring cylinder to 24rpm, regulating the stirring speed to 1250rpm, regulating the vacuum degree to-0.09 MPa, adding the glue solution into the product of the step (III), and after the materials are added, continuously revolving and stirring the stirring cylinder for 130min to obtain the lithium ion battery anode slurry.
Example 3
The raw material ratio of the lithium ion battery anode slurry is prepared in the embodiment; the lithium ion battery positive electrode slurry comprises the following components in percentage by mass as 100 percent:
Figure BDA0002515992390000131
the glue solution is a mixed solution of N-methyl pyrrolidone and polyvinylidene fluoride, and the solid content of the mixed solution is 10%.
The average particle diameter of the lithium iron phosphate powder is 0.6 μm, and the average particle diameter of the conductive carbon black SP is 50nm.
The preparation method of the glue solution comprises the following steps: sequentially adding N-methyl pyrrolidone and polyvinylidene fluoride into a stirring tank, and mixing for 240min under the conditions that the revolution speed is 26rpm and the stirring dispersion speed is 1950rpm to obtain the glue solution.
The preparation method of the lithium ion battery anode slurry in the embodiment comprises the following steps:
adding 60wt% of lithium iron phosphate powder, 100wt% of conductive carbon black SP and 90wt% of N-methyl pyrrolidone in a formula into a 1500L Ross stirring cylinder with revolution speed of 11rpm simultaneously and automatically, wherein the N-methyl pyrrolidone is added in a spraying mode, the spraying speed is 0.21Kg/s, and the stirring cylinder continuously revolves for 50min after the materials are added;
(II) regulating the revolution speed of the stirring cylinder to be 14rpm, regulating the stirring speed to be 550rpm, then adding the rest 40wt% of lithium iron phosphate powder and 100wt% of carbon nanotube conductive slurry into the stirring cylinder at the same time, wherein the carbon nanotube conductive slurry is added in a spraying mode, the spraying speed is 0.11Kg/s, and the stirring cylinder continues revolution and stirring for 80min after the materials are added;
(III) regulating the revolution speed of the stirring cylinder to 21rpm, regulating the stirring speed to 950rpm, spraying and adding the rest 10wt% of N-methyl pyrrolidone into the product obtained in the step (II), wherein the spraying speed is 0.21Kg/s, and after the material is added, continuing to revolve and stir for 70min;
and (IV) regulating the revolution speed of the stirring cylinder to 26rpm, regulating the stirring speed to 1150rpm, regulating the vacuum degree to-0.095 MPa, adding the glue solution into the product of the step (III), and after the materials are added, continuously revolving the stirring cylinder and stirring for 110min to obtain the lithium ion battery anode slurry.
Example 4
This example differs from example 1 in that in step (I) 100% by weight of N-methylpyrrolidone is added; the procedure of step (III) was not carried out, and the other conditions were exactly the same as those in example 1.
Example 5
This example differs from example 1 in that 100wt% of lithium iron phosphate powder was added in the formulation amount in step (i), i.e., 100wt% of carbon nanotube conductive paste was added alone in step (ii), and the other conditions were exactly the same as in example 1.
Example 6
The difference between this example and example 1 is that in step (ii), the conductive paste is added by direct pouring and mixing, and is not added by spraying, and the other conditions are exactly the same as those in example 1.
Comparative example 1
The composition of the lithium ion battery positive electrode slurry in this comparative example was exactly the same as in example 1, except that the preparation method of the lithium ion battery positive electrode slurry in this comparative example comprises the steps of:
(1) Adding all lithium iron phosphate powder into a stirring cylinder, then adding conductive carbon black SP, and stirring and mixing;
(2) Adding carbon nanotube conductive paste into the mixture in the step (1), then adding glue solution, and stirring;
(3) And (3) adding half of the volume of the solvent into the mixture in the step (2), stirring, adding the other half of the solvent, and stirring to obtain the lithium ion battery positive electrode slurry of the comparative example.
The lithium battery anode slurry obtained by the method of the comparative example has larger viscosity and unstable slurry coating surface density.
Performance test:
testing the viscosity of the prepared lithium ion battery anode slurry under the test condition of a No. 4 rotor and 12 revolutions per minute;
and testing the fineness of the prepared lithium ion battery anode slurry, and performing filtering plugging test, wherein the screen adopted in the test is a 200-mesh filter screen, the testing method of plugging times is that the slurry can not be filtered from the filter screen by visual observation, and the plugging test is a statistical result.
The viscosity, fineness, and filtering blocking test result of the slurry obtained by the above test and the time required for the preparation process are shown in table 1;
TABLE 1
Figure BDA0002515992390000161
As can be seen from table 1, the lithium ion battery anode slurry obtained by the preparation method of the lithium ion battery anode slurry has lower viscosity, the mixing uniformity is obviously improved, and the number of times of filtering and blocking the obtained lithium ion battery anode slurry is less than or equal to 1 time; is obviously better than comparative example 1; the preparation method of the lithium ion battery anode slurry has short time consumption, the time required by the method for preparing the anode slurry once can reach less than 6 hours, and the preparation time of the anode slurry required in comparative example 1 is 8 hours.
The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.

Claims (32)

1. The preparation method of the lithium ion battery anode slurry is characterized by comprising the following steps of:
(1) Adding active material powder into a mixer, wherein the addition process of the active material powder is accompanied by the addition of conductive carbon black and the addition of a solvent, and the addition of the solvent is carried out in a spraying mode; the solvent is sprayed on the inner wall of the mixer in the spraying process; the spraying rate of the solvent is 0.2-0.22Kg/s, and the adding rate of the active substance powder is 0.3-0.35Kg/s;
(2) Adding active material powder into a mixer in the step (1), wherein the adding process of the active material powder is accompanied by adding conductive paste, and mixing, wherein the conductive paste is added in a spray mode;
(3) Spraying and adding a solvent into the product obtained in the step (2), and mixing;
(4) And (3) adding glue solution into the product of the step (3), and mixing to obtain the lithium ion battery anode slurry.
2. The method of claim 1, wherein the ratio by mass of the amount of the active material powder added in the step (1) to the amount of the active material powder added in the step (2) is (4-6): 4-6.
3. The process according to claim 1, wherein the ratio of the amount of the solvent added in the step (1) to the amount of the solvent added in the step (3) is (8-9): 2-1.
4. The method of claim 1, wherein the active material powder comprises at least one of lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium cobalt oxide, and lithium manganese oxide.
5. The method of claim 1, wherein the solvent comprises N-methylpyrrolidone and/or absolute ethanol.
6. The method of claim 1, wherein the conductive carbon black of step (1) comprises conductive carbon black SP.
7. The method of manufacturing according to claim 1, wherein the mixer is a stirred tank.
8. The method of claim 7, wherein the stirring cylinder is provided with an active material powder inlet, a conductive paste inlet, a conductive carbon black inlet, a solvent inlet, and a glue inlet, respectively.
9. The method of claim 7, wherein the mixing in step (1) is performed by revolving a stirring vessel at a revolution rate of 9 to 11rpm.
10. The method of claim 1, wherein the conductive paste of step (2) comprises a carbon nanotube conductive paste.
11. The method of claim 10, wherein the conductive paste in step (2) is a carbon nanotube paste having a solid content of 4 to 6%.
12. The method of claim 1, wherein the spraying rate of the conductive paste in the step (2) is 0.1 to 0.12Kg/s.
13. The method of claim 7, wherein the revolution rate of the stirring vessel is 14 to 16rpm and the stirring rate of the stirring vessel is 450 to 550rpm during the addition of the active material powder and the electroconductive paste in step (2).
14. The process of claim 1, wherein the mixing is continued for 80-100 minutes after the addition of the material in step (2) is completed.
15. The process according to claim 1, wherein the solvent in step (3) is sprayed at a rate of 0.2 to 0.22Kg/s.
16. The method of claim 1, wherein the solvent in step (3) is sprayed onto the inner wall of the mixer during spraying.
17. The method according to claim 7, wherein the revolution rate of the stirring cylinder during the spraying of the solvent in the step (3) is 19 to 21rpm and the stirring rate is 950 to 1050rpm.
18. The process according to claim 1, wherein the duration of mixing is 50 to 70 minutes after the completion of spraying in step (3).
19. The method of claim 1, wherein the gum solution in step (4) is a mixed solution of polyvinylidene fluoride and N-methylpyrrolidone.
20. The method of claim 1, wherein the gum solution in step (4) has a solids content of 6-10%.
21. The preparation method according to claim 7, wherein the revolution rate of the stirring cylinder is 24-26rpm and the stirring rate is 1150-1250rpm during the addition of the dope in the step (4).
22. The method according to claim 1, wherein the vacuum degree is less than or equal to-0.085 MPa in the process of adding the glue solution in the step (4).
23. The method of claim 1, wherein the glue solution is added in step (4) at a temperature of 22-28 ℃.
24. The method of claim 1, wherein the step (4) is performed for 110-130 minutes after the glue is added.
25. The method of preparing a dope as claimed in claim 7, wherein the method of preparing a dope in step (4) comprises adding N-methylpyrrolidone and polyvinylidene fluoride powder to a stirring cylinder and mixing, wherein the revolution rate of the stirring cylinder is 24-26rpm, and the stirring rate is 1950-2050rpm; the mixing time is 240-480min.
26. The method of claim 7, wherein the step (4) further comprises adjusting the viscosity after the mixing is completed.
27. The method according to claim 26, wherein the revolution rate of the stirring cylinder is 9 to 11rpm, the stirring rate is 950 to 1050rpm, and the vacuum degree is less than or equal to-0.085 MPa in the process of adjusting the viscosity in the step (4).
28. The method of claim 26, wherein the viscosity is adjusted at a temperature of 22-28 ℃.
29. The method of claim 26, wherein the viscosity is adjusted in step (4) by adding a solvent.
30. The method of preparation according to claim 1, characterized in that the method comprises the steps of:
adding lithium iron phosphate powder into a stirring cylinder with the revolution speed of 9-11rpm, wherein the addition process of the lithium iron phosphate powder is accompanied by the addition of conductive carbon black SP and N-methyl pyrrolidone, the N-methyl pyrrolidone is added in a spraying mode, and the stirring cylinder continues to revolve for 50-70min after the material is added;
(II) regulating the revolution speed of the stirring cylinder to be 14-16rpm, regulating the stirring speed to be 450-550rpm, adding lithium iron phosphate powder into the stirring cylinder, wherein the adding process of the lithium iron phosphate powder is accompanied with the adding of conductive paste of the carbon nano tubes, the conductive paste of the carbon nano tubes is added in a spraying mode, and the continuous revolution and stirring time of the stirring cylinder is 80-100min after the material is added;
(III) regulating the revolution speed of the stirring cylinder to be 19-21rpm, regulating the stirring speed to be 950-1050rpm, spraying N-methyl pyrrolidone into the product of the step (II), spraying N-methyl pyrrolidone on the inner wall of the stirring cylinder in the spraying process, and continuously revolving and stirring the stirring cylinder for 50-70min after the materials are added;
(IV) regulating the revolution speed of the stirring cylinder to 24-26rpm, regulating the stirring speed to 1150-1250rpm, regulating the vacuum degree to less than or equal to-0.085 MPa, adding the glue solution into the product of the step (III), and continuously revolving and stirring the stirring cylinder for 110-130min after the materials are added;
(V) regulating the revolution speed of the stirring cylinder to 9-11rpm, stirring the lithium ion battery at 950-1050rpm, and keeping the vacuum degree less than or equal to-0.085 MPa for 0-60min to obtain the lithium ion battery anode slurry.
31. The lithium ion battery positive electrode slurry prepared by the method according to any one of claims 1 to 30, wherein the viscosity of the lithium ion battery positive electrode slurry is 10000 to 25000 mPa-s.
32. The lithium ion battery positive electrode slurry according to claim 31, wherein the fineness of the lithium ion battery positive electrode slurry is 4-8 μm.
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