WO2018126970A1

WO2018126970A1 - Method for preparing lithium-ion battery slurry

Info

Publication number: WO2018126970A1
Application number: PCT/CN2017/119058
Authority: WO
Inventors: 赖真龙; 武永强
Original assignee: 深圳拓邦新能源技术有限公司
Priority date: 2017-01-09
Filing date: 2017-12-27
Publication date: 2018-07-12
Also published as: CN106784794A

Abstract

The present invention relates to a method for preparing lithium-ion battery slurry, comprising the following steps: S1, mixing an active material and an auxiliary at low speed to form mixed powder; S2, adding part of a solvent into the mixed powder, and performing variable-speed and positive-negative rotation reversing stirring for uniform mixing to form a mixed material; S3, adding the remaining solvent into the mixed material, and performing variable-speed and positive-negative rotation reversing stirring under the vacuum state for uniform dispersing to form lithium-ion battery slurry. According to the present invention, in the stirring process, performing variable-speed and reversing stirring can quickly mix raw materials uniformly; and according to a chaotic mixing principle, the mixing efficiency is improved, and the purposes of shortening the mixing and stirring time and improving the mixing uniformity are achieved, the energy consumption is reduced and the production efficiency is improved in the production process, and production costs are reduced.

Description

Method for preparing lithium ion battery slurry

[0001] The present invention relates to the field of lithium ion battery technology, and more particularly to a method of preparing a lithium ion battery slurry.

Background technique

[0002] Lithium-ion battery is the best choice for mobile equipment and automotive power supply because of its advantages of light weight, large energy storage, high power, no pollution, long life, small self-discharge coefficient and wide temperature adaptation range. The prospects are very broad.

[0003] A lithium ion battery is obtained by winding a positive and negative electrode sheet and a separator into a battery, and then charging the electrolyte after being placed in a casing. On the other hand, the positive and negative electrode sheets are obtained by dispersing the active material of the positive and negative electrodes in a solvent to form a slurry, and uniformly applying the slurry to the current collector for drying. The slurry contains not only the positive and negative active materials, but also other powder excipients such as a binder, a conductive agent, and a thickener. The characteristics of each material are different, and the process of mixing them with the liquid is as follows. Question:

[0004] 1. The powder is difficult to uniformly disperse into the liquid solvent;

[0005] 2. The powder is difficult to maintain the suspension stability between long turns in a solvent;

[0006] 3. The mixing time is long, and the energy consumption of the equipment is high;

[0007] 4. Equipment utilization is low.

technical problem

[0008] The technical problem to be solved by the present invention is to provide a preparation of a lithium ion battery slurry which is uniformly mixed and can efficiently prepare a battery slurry having good dispersibility and stability in view of the above-mentioned drawbacks of the prior art. method.

Problem solution

Technical solution

[0009] The technical solution adopted by the present invention to solve the technical problem thereof is: constructing a preparation method of a lithium ion battery slurry, comprising the following steps: [0010] Sl, mixing the active material and the auxiliary agent at a low speed to form a mixed powder;

[0011] S2, adding a part of the solvent to the mixed powder, using a shifting and forward-reverse conversion to stir, mixing evenly

Forming a mixture;

[0012] S3, adding the remaining solvent to the mixture, and uniformly dispersing and dispersing in a vacuum state by using a shifting and forward-reverse conversion to form a lithium ion battery slurry.

[0013] In the preparation method of the present invention, the step S3 comprises: adding the remaining solvent to the mixture, using a shifting and reversing agitation under vacuum to uniformly mix, adding a styrene-butadiene rubber solution, low speed Stir for 30 minutes to form a lithium ion battery slurry.

[0014] In the preparation method of the present invention, in step S3, the variable speed stirring speed is from 0r/mi _n to _40r /min, and the forward and reverse conversion to the stirring period is 2 to 10 minutes; the low speed is 10 to 20r. /min.

[0015] In the preparation method of the present invention, the active material is a positive electrode active material or a negative electrode active material, the auxiliary agent includes a binder and a conductive agent, and the solvent is N-methylpyrrolidone or deionized. water.

[0016] In the preparation method of the present invention, the positive active material is LiNi _x M _ni — _x 0 ₂ , LiCo0 ₂

, LiCo !_ _(x+y) Ni _x Mn _y O ₂ , Li ₂ MnO ₄ , LiFePO ₄

One or more of them, wherein x, y, x+y are all less than 1; and the negative active material is one or more of artificial graphite, natural graphite, and mesocarbon microbeads.

[0017] In the preparation method of the present invention, the binder is one or more of polyvinylidene fluoride, polytetrafluoroethylene, acrylate, polyurethane, sodium carboxymethylcellulose; The conductive agent is one or more of conductive carbon black, conductive graphite, and carbon fiber.

[0018] In the preparation method of the present invention, in step S1, the mixing time is 10 to 30 minutes, and the low speed is 1

0~20r/min; In step S3, the stirred and dispersed crucible is 30 to 120 minutes, and the vacuum degree in the vacuum state is -0.090 MPa to -0.1 MPa.

In the preparation method of the present invention, in step S2, the total amount of the solvent added is 10<3⁄4~60<3⁄4 of the active material, and 30~120 minutes between the mixed turns.

[0020] In the preparation method of the present invention, in step S2, the variable speed stirring speed is from 0 r/mi _n to 40 _r /min, and the forward and reverse conversion to the stirring period is 2 to 10 minutes.

[0021] In the preparation method of the present invention, in step S3, the variable speed stirring speed is from 0 r/mi _n to 40 _r /min, and the forward-reverse conversion to the stirring period is 2 to 10 minutes. Advantageous effects of the invention

Beneficial effect

[0022] The beneficial effects of the invention: In the stirring process, the shifting and the commutating stirring can be used to quickly mix the raw materials uniformly, and the lithium ion battery slurry with good dispersibility and stability can be prepared with high efficiency, and the principle of chaotic mixing is utilized. The mixing efficiency is improved, the mixing and mixing time is shortened, and the mixing uniformity is improved, so that the energy consumption in the production process is low, the production efficiency is improved, and the production cost is lowered.

Brief description of the drawing

DRAWINGS

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

1 is a flow chart of a first embodiment of a method for preparing a lithium ion battery slurry of the present invention;

2 is a flow chart of a second embodiment of a method for preparing a lithium ion battery slurry of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0027] The present invention discloses a method for preparing a lithium ion battery slurry, which adopts a method of shifting and reversing agitation in a stirring process to rapidly mix raw materials uniformly, and can efficiently prepare a dispersion with high efficiency. The lithium ion battery slurry of the nature and stability utilizes the principle of chaotic mixing to improve the mixing efficiency, shorten the mixing and mixing time, and improve the mixing uniformity, so that the energy consumption in the production process is low and the production efficiency is improved. , production costs are reduced.

[0028] Referring to FIG. 1, a method for preparing a lithium ion battery slurry of the present invention comprises the following steps:

[0029] Sl, mixing the active material and the auxiliary agent at a low speed to form a mixed powder. In this step, the mixing time is 10~30 minutes, and the low speed is 10~20r/min. The mixing mode is not limited, and can be selected according to actual needs. Preferably, the mixed powder of step S1 is formed by mixing at a low speed in a dual planetary mixer.

[0030] wherein the active material is a positive electrode active material or a negative electrode active material, and the auxiliary agent includes a binder and a conductive agent.

The positive electrode active material is one or more of LiNi _x Mn _x 0 ₂ , LiCoO ₂ , LiCo ( _x+y )Ni _x Mn _y O ₂ , Li ₂ MnO ₄ , LiFeP0 ₄ , wherein x, y, x+ y is greater than 0 and less than 1. Further, the positive electrode The active material is preferably one or more of Li 2 Mn 04 , LiFeP 04 , and LiCo 02 .

[0031] The anode active material is one or more of artificial graphite, natural graphite, and mesocarbon microbeads. It is preferably artificial graphite or natural graphite.

[0032] The binder is one or more of polyvinylidene fluoride, polytetrafluoroethylene, acrylate, polyurethane, sodium carboxymethylcellulose, vinylidene fluoride, hexafluoropropylene, preferably polycondensation One or two of vinyl fluoride and sodium carboxymethyl cellulose. The conductive agent is one or more of conductive carbon black, conductive graphite, and carbon fiber, and is preferably one or both of conductive carbon black and conductive graphite.

[0033] S2, a part of the solvent is added to the mixed powder, and the mixture is stirred and mixed uniformly by shifting and forward-reverse conversion to form a mixed material. The mixing time is 30 to 120 minutes. Further, the mixing time is preferably 60 to 90 minutes. Further, the mixing time is preferably 75 to 80 minutes. The variable speed stirring speed is from 0r/mi _n ~40r/min, and the forward and reverse conversion to the stirring period is 2~10 minutes. Further, the variable speed stirring speed is preferably from 0 r/mi _n to 30 _r /min, and the forward-reverse conversion to the stirring period is preferably 5 to 7 minutes.

[0034] The agitation mixing in the step S2 may be referred to as kneading, and the amount of the solvent may be appropriately added according to the solid content requirement, and may be selected according to actual needs to satisfy the viscosity requirement of the final slurry. Preferably, the solvent is N-methylpyrrolidone or deionized water. When the active material is a positive electrode active material 吋, the solvent is preferably N-methylpyrrolidone; the active material is a negative electrode active material 吋, and the solvent is preferably deionized water.

In a preferred embodiment, the total amount of the solvent added in step S2 is 10<3⁄4 to 60% of the active material.

Further, the amount of the solvent added is preferably from 30% to 50% of the active material. Further, the amount of the solvent added is preferably ^ SO ^ of the active material.

[0036] S3, adding the remaining solvent to the mixture, and uniformly dispersing and dispersing in a vacuum state by using a shifting and forward-reverse conversion to form a lithium ion battery slurry. In the step S3, the amount of the remaining solvent to be added is not particularly limited, and may be appropriately added depending on the solid content requirement. The stirred and dispersed crucible is 30 to 120 minutes, and the vacuum degree in a vacuum state is -0.090 MPa to - 0.1 Mpa. Further, the mixing time is preferably 60 to 90 minutes. Further, the mixing time is preferably 75 to 80 minutes. The speed of the variable speed stirring is from 0r/mi _n to _40r /min, preferably from 0r/mi _n to _30r /min. The period of the forward-reverse conversion to the stirring is 2 to 10 minutes, preferably 5 to 7 minutes. .

In a preferred embodiment, the linear velocity of the agitation dispersion in step S3 is 5 to 25 m/s. Further, the dispersion linear velocity is preferably 10 to 20 m/s. Further, the dispersion linear velocity is preferably 15 to 20 m/s.

[0038] Referring to FIG. 2, when preparing a lithium ion battery negative electrode slurry, step S3 includes: adding the remaining solvent to the mixture In the combined material, the shifting and reversing agitation were carried out under vacuum to uniformly mix, and a styrene butadiene rubber (SBR) solution was added, and the mixture was stirred at a low speed in the forward or reverse direction for 30 minutes to form a lithium ion battery slurry. In the step S3, the variable speed stirring speed is from 0r/mi _n to 40r/min, and the forward and reverse conversion to the stirring period is 2 to 10 minutes; the low speed is 10 to 20r/min, and the vacuum degree in the vacuum state is -0.090MPa~ 0.1 Mpa.

[0039] In the above preparation method, the amount of the raw materials such as the binder, the conductive agent, and the lithium iron phosphate powder is weighed according to the ratio of the raw materials of the positive electrode slurry, and can be achieved by setting the ratio in the prior art.

[0040] By using the preparation method of the present invention, when the active material used is a positive electrode active material, a lithium ion battery positive electrode slurry can be prepared, and the lithium ion battery positive electrode slurry can be used to form a pole piece as a positive electrode of a lithium ion battery. The lithium ion battery negative electrode slurry can be prepared when the active material used is a negative electrode active material, and the lithium ion battery negative electrode slurry can be used to form a pole piece as a negative electrode piece of a lithium ion battery.

[0041] The pole piece was fabricated, and the lithium ion battery slurry prepared above was coated on an aluminum foil and dried.

[0042] The positive electrode sheet and the negative electrode sheet and the separator are stacked and wound into a core, and the core is placed in an aluminum shell, and an electrolyte is injected and sealed to obtain a lithium ion battery.

[0043] The invention will now be described in the context of specific embodiments.

[0044] The following examples and comparative examples were carried out in a completed double planetary mixer in a DP-25 double planetary mixer.

[0045] Example 1 :

[0046] setting each of the following representatives lOOOOg;

[0047] taking 2.5 parts of PVDF (polyvinylidene fluoride), 2 parts of Super-P (conductive carbon black), 1 part of KS-6 (conductive graphite) and 94.5 parts of lithium iron phosphate, added to the mixer and uniformly mixed at 10r rotation speed The mixed powder was formed in 20 minutes. Add 47 parts of N-methylpyrrolidone, accelerate from Or/min to 30r/min, stir at a constant speed for 5min, stop stirring, decelerate from 30r/min to 0r/min, start reverse mixing, and stir from 0r/min Stir at a constant speed for 5 min at 30 r/m in. During the process, the dispersion was continuously operated at a speed of 15 m/s for a total of 80 minutes. After adding 53 parts of N-methylpyrrolidone, evacuate to -0.095Mpa, stir from Or/min to 30r/min, stir at a constant speed for 5min, stop stirring, and the stirring speed is decelerated from 30r/min to Or/min. Stir, stir from Or/min to 30r/min, stir at a constant speed for 5min, and cycle. During the process, the dispersion was continuously operated at a speed of 15 m/s, and the total daytime was 80 minutes to form a positive electrode slurry of a lithium ion battery.

Example 2: [0049] setting each of the following represents lOOOOg;

[0050] 1.5 parts of CMC (carboxymethylcellulose sodium), 1.5 parts of Super-P (conductive carbon black), and 94.8 parts of artificial graphite were placed, and uniformly mixed at a rotational speed of 10 rpm for 30 minutes in a mixer to form a mixed powder. Add 48 parts of deionized water, stir from 0r/min to 30r/min, stir at a constant speed for 5min, stop stirring, decelerate from 30r/mi n to 0r/min, start reverse mixing, and accelerate from 0r/min to 30r/min, stir at a constant speed for 5min, and cycle. During the process, the dispersion was continuously run at 18 m/s for 90 minutes. After adding 52 parts of deionized water, evacuate to -0.095Mpa, stir from 0r/min to 30r/min, stir at a constant speed for 5min, stop stirring, decelerate from 30r/min to 0r/min, start reverse mixing. Stirring was accelerated from Or/min to 30 r / min, stirred at a constant rate for 5 min, and cycled. During the process, the dispersion was continuously operated at 18 m/s and the total time was 90 minutes. 5 parts of SBR emulsion was added, stirred at 25 r/min, dispersed at a line speed of 5 m/s, and mixed for 30 minutes to form a negative electrode slurry of a lithium ion battery.

Comparative Example 1 :

[0052] setting each of the following representatives lOOOOg;

[0053] taking 2.5 parts of PVDF (polyvinylidene fluoride), 2 parts of Super-P (conductive carbon black), 1 part of KS-6 (conductive graphite) and 94.5 parts of lithium iron phosphate, added to the mixer and uniformly mixed at 10r rotation speed The powder was formed in 20 minutes. 47 parts of N-methylpyrrolidone was added, and the stirring was continued at a stirring speed of 30 _r /min, and the stirring speed was 15 m/s, and the mixture was continuously stirred for 120 minutes. After adding 53 parts of N-methylpyrrolidone, vacuuming to -0.095Mpa, stirring at a rate of 30r/min, stirring at a speed of 15m/s, and stirring for a total of 120 minutes, forming a positive ion slurry of lithium ion battery

Comparative Example 2:

[0055] setting the following representative to each 1000g _;

[0056] 1.5 parts of CMC (carboxymethylcellulose sodium), 1.5 parts of Super-P (conductive carbon black), and 94.8 parts of artificial graphite were placed, and uniformly mixed for 30 minutes at a rotational speed of 10 rpm in a mixer to form a powder. 48 parts of deionized water was added, stirring was continued at a stirring speed of 30 r/min, and the stirring speed was maintained at a speed of 18 m/s for a total of 150 minutes. After adding 52 parts of deionized water, evacuate to -0.095 MPa, stirring at a rate of 30 r/min, and stirring at a speed of 18 m/s for a total of 150 minutes. 5 parts of SBR emulsion was added, stirred at 25 r/min, dispersed at a line speed of 5 m/s, and mixed for 30 minutes to form a negative electrode slurry of a lithium ion battery.

The total inter-turn statistics and slurry test results of Examples 1, 2 and Comparative Examples 1, 2 are shown in Table 1 below. Table 1. Total inter-day statistics and slurry test results

[] [Table 1]

[0059] From the experimental results shown in Table 1, the mixing methods of Examples 1 and 2 have little difference in effect compared with the conventional (Comparative Examples 1 and 2) mixing methods, but are obviously shorter in the daytime. 27%~31%, the efficiency is improved and the energy consumption is reduced.

[0060] It is to be understood that the above embodiments are merely illustrative of the preferred embodiments of the present invention, and are not to be construed as limiting the scope of the invention; A person skilled in the art can freely combine the above technical features without departing from the inventive concept, and can also make several modifications and improvements, which are all within the scope of the present invention; therefore, the rights of the present invention Equivalent transformations and modifications made to the scope of the claims are intended to be included within the scope of the appended claims.

Claims

Claim

A method for preparing a lithium ion battery slurry, comprising the steps of:

S1, mixing the active material and the auxiliary agent at a low speed to form a mixed powder;

52, adding a part of the solvent to the mixed powder, using a shifting and forward-reverse conversion to stir, mixing uniformly to form a mixed material;

53. The remaining solvent is added to the mixture, and the dispersion and dispersion are uniformly dispersed in a vacuum state by using a shifting and forward-reverse conversion to form a lithium ion battery slurry.

The preparation method according to claim 1, wherein the step S3 comprises: adding the remaining solvent to the mixture, and using a shifting and reversing agitation under vacuum to uniformly mix, adding a styrene-butadiene rubber solution, Stir at low speed for 30 minutes to form a lithium ion battery slurry.

The preparation method according to claim 2, wherein in step S3, the variable speed stirring speed is from 0 _r /mi _n to 40 _r /min, and the forward and reverse conversion to the stirring period is 2 to 10 minutes; ~20r/min.

The preparation method according to claim 1, wherein the active material is a positive electrode active material or a negative electrode active material, and the auxiliary agent comprises a binder and a conductive agent, and the solvent is N-methylpyrrolidone or Ionic water.

The method according to claim 4, wherein the positive active material is

One or more of LiNi _x Mn _lx 0 ₂ , LiCo0 ₂ , LiCo _x+y ) Ni _x Mn _y O ₂ , Li ₂ Mn0 ₄ , LiFePO ₄ , wherein x, y, _x+y are all less than 1; The negative active material is one or more of artificial graphite, natural graphite, and mesocarbon microbeads.

The preparation method according to claim 4, wherein the binder is one or more of polyvinylidene fluoride, polytetrafluoroethylene, acrylate, polyurethane, sodium carboxymethylcellulose; The conductive agent is one or more of conductive carbon black, conductive graphite, and carbon fiber. The preparation method according to claim 1, wherein in step S1, the mixing time is 10 to 30 minutes, and the low speed is 10 to 20 r/min; in step S3, the mixing time is 30 to 12

At 0 minutes, the vacuum in the vacuum state was -0.090 MPa to -0.1 MPa.

The preparation method according to claim 1, wherein in the step S2, the solvent The total amount of addition is 10%~60<3⁄4 of the active material, and the mixing and dispersing time is 30~120 minutes.

[Claim 9] The preparation method according to claim 1, wherein in step S2, the variable speed stirring speed is from 0 r/min to 40 r/min, and the forward-reverse conversion to the stirring period is 2 to 10 minutes.

[Claim 10] The preparation method according to claim 1, wherein in step S3, the variable speed stirring speed is from 0r/mi _n to 40r/min, and the forward and reverse conversion to the stirring period is 2 to 10 minutes.