阅读说明：本技术 一种正极浆料制造方法 (Method for manufacturing anode slurry ) 是由 张卫龙 于 2021-07-02 设计创作，主要内容包括：本发明的实施例提供了一种正极浆料制造方法,涉及锂电池技术领域。正极浆料制造方法包括将占PVDF总量的第一比例的PVDF与占NMP的第二比例的NMP混合制胶形成第一胶液；混合第一主材、硅碳及剩余的PVDF干混得到第一干粉；将第一胶液逐渐加入至第一干粉中混合以制得正极浆料。在本发明实施例中,采用干混的方式在第一主材中加入硅碳,再进行湿混,能够提高正极浆料的稳定性。(The embodiment of the invention provides a method for manufacturing anode slurry, and relates to the technical field of lithium batteries. The preparation method of the positive electrode slurry comprises the steps of mixing PVDF accounting for the total amount of the PVDF in a first proportion with NMP accounting for a second proportion of the NMP to prepare a first glue solution; mixing the first main material, silicon carbon and the rest PVDF to obtain first dry powder in a dry mixing way; and gradually adding the first glue solution into the first dry powder and mixing to prepare the anode slurry. In the embodiment of the invention, silicon carbon is added into the first main material in a dry mixing mode and then wet mixing is carried out, so that the stability of the anode slurry can be improved.)

1. A method for manufacturing positive electrode slurry, which is used for manufacturing positive electrode slurry, is characterized by comprising the following steps:

mixing PVDF accounting for a first proportion of the total amount of the PVDF and NMP accounting for a second proportion of the NMP to prepare glue to form a first glue solution;

mixing the first main material, silicon carbon and the rest PVDF to obtain first dry powder in a dry mixing way;

and gradually adding the first glue solution into the first dry powder and mixing to obtain the anode slurry.

2. The method for manufacturing positive electrode slurry according to claim 1, wherein the step of dry-blending the first main material, the silicon carbon, and the remaining PVDF to obtain the first dry powder comprises:

mixing the first main material and the silicon carbon to obtain a first raw material;

gradually adding the remaining PVDF to the first raw material to obtain the first dry powder.

3. The method for manufacturing a positive electrode slurry according to claim 2, wherein the step of gradually adding the remaining PVDF to the first raw material to obtain the first dry powder comprises:

and gradually adding the rest PVDF and all the first conductive agent into the first raw material to carry out dry mixing to obtain the first dry powder.

4. The method for manufacturing the positive electrode slurry according to claim 1, wherein the step of gradually adding the first glue solution into the first dry powder and mixing to obtain the positive electrode slurry comprises:

gradually adding the first glue solution into the first dry powder to obtain a second raw material;

adding the rest NMP into the second raw material to obtain a third raw material;

adding a CNT solvent into the third raw material to obtain a fourth raw material;

and preserving the fourth raw material in vacuum to obtain the anode slurry.

5. The method for manufacturing the positive electrode slurry according to claim 4, wherein the step of gradually adding the first glue solution to the first dry powder to obtain a second raw material comprises:

stirring at a first rotation speed while adding the first glue solution to the first dry powder;

and stirring the first glue solution at a second rotating speed for a first preset time after the first glue solution is added, so as to obtain the second raw material, wherein the first rotating speed is lower than the second rotating speed.

6. The method for manufacturing a positive electrode slurry according to claim 5, wherein the first rotation speed is 5 to 10rpm in terms of stirring revolution, the first rotation speed is 200 to 500rpm in terms of stirring rotation, the second rotation speed is 30 to 80rpm in terms of stirring revolution, the first rotation speed is 1000 to 3000rpm in terms of stirring rotation, and the first predetermined time is 10 to 30 min.

7. The method for producing a positive electrode slurry according to claim 4, wherein the step of adding excess NMP to the second raw material to obtain a third raw material comprises:

stirring at a third rotational speed during the addition of the remaining NMP to the second feedstock;

and stirring at a fourth rotating speed for a second preset time after the NMP is added, so as to obtain the third raw material, wherein the third rotating speed is less than the fourth rotating speed.

8. The method for producing a positive electrode slurry according to claim 7, wherein the third rotation speed is a stirring revolution rotation speed of 10rpm to 20rpm, and the third rotation speed is a stirring rotation speed of 300rpm to 500 rp; the stirring revolution rotating speed of the fourth rotating speed is 30rpm-60rpm, and the stirring rotation rotating speed of the fourth rotating speed is 1500rpm-2500 rp; the second preset time is 30-40 min.

9. The method for manufacturing positive electrode slurry according to claim 4, wherein the step of adding a CNT solvent to the third raw material to obtain a fourth raw material comprises:

stirring at a fifth rotating speed for a third preset time in the process of adding CNT into the third raw material, wherein the stirring revolution rotating speed of the fifth rotating speed is 20rpm-50rpm, and the stirring rotation rotating speed of the fifth rotating speed is 1000rpm-2000 rp; the third preset time is 10min-20 min.

10. The method for producing a positive electrode slurry according to claim 4, wherein the step of vacuum-storing the fourth raw material to obtain the positive electrode slurry comprises:

vacuumizing to a first preset pressure, and stirring at a sixth rotating speed for a fourth preset time to obtain the anode slurry, wherein the first preset pressure is-0.085 Mpa, the stirring revolution rotating speed of the sixth rotating speed is 10-20 rpm, and the stirring rotation rotating speed of the sixth rotating speed is 300-500 rp; the fourth preset time is 5min-15 min.

Technical Field

The invention relates to the technical field of lithium batteries, in particular to a method for manufacturing anode slurry.

Background

In the lithium battery industry, compared with nickel-cadmium and nickel-hydrogen batteries, the lithium ion battery has the advantages of high specific energy, high working voltage, low self-discharge rate, long cycle life, no pollution, wide application range and the like. The preparation of the electrode slurry is the most critical ring in the whole process, and the quality of the electrode slurry directly influences whether the next process can be carried out. The slurry is prepared by uniformly mixing powder and liquid such as active substances, adhesives, solvents, thickeners and the like to form a non-Newtonian high-viscosity fluid, and the fluid needs to have certain viscosity, good fluidity and sufficiently small particle size. The electrode slurry is composed of a plurality of raw materials with different specific gravities and different particle sizes, and is prepared by mixing and dispersing solid and liquid phases, and the formed slurry belongs to non-Newtonian fluid. The lithium battery slurry is divided into two types of positive electrode slurry and negative electrode slurry, and the properties of the slurry are different due to different slurry systems, namely different oil properties and different water properties, so that the most common wet-type slurry making method is used in the industry at present to prepare the positive electrode slurry. The anode slurry manufactured by the method has poor stability, and the problems of thicker thickness, low capacity and the like easily occur in the coating process.

Disclosure of Invention

The invention aims to provide a method for manufacturing positive electrode slurry, which can improve the stability of the positive electrode slurry and reduce the influence caused by coating the positive electrode slurry, thereby improving the charge and discharge performance and energy density of a battery and reducing the internal resistance.

Embodiments of the invention may be implemented as follows:

the embodiment of the invention provides a method for manufacturing anode slurry, which is used for manufacturing the anode slurry and comprises the following steps:

mixing PVDF accounting for a first proportion of the total amount of the PVDF and NMP accounting for a second proportion of the NMP to prepare glue to form a first glue solution;

mixing the first main material, silicon carbon and the rest PVDF to obtain first dry powder in a dry mixing way;

and gradually adding the first glue solution into the first dry powder and mixing to obtain the anode slurry.

In an alternative embodiment of the present invention, the step of dry-mixing the first main material, the silicon carbon and the remaining PVDF to obtain the first dry powder comprises:

mixing the first main material and the silicon carbon to obtain a first raw material;

gradually adding the remaining PVDF to the first raw material to obtain the first dry powder.

In an alternative embodiment of the invention, the step of gradually adding the remaining PVDF to the first raw material to obtain the first dry powder comprises:

and gradually adding the rest PVDF and all the first conductive agent into the first raw material to carry out dry mixing to obtain the first dry powder.

In an optional embodiment of the present invention, the step of gradually adding the first glue solution to the first dry powder and mixing to obtain the cathode slurry includes:

gradually adding the first glue solution into the first dry powder to obtain a second raw material;

adding the rest NMP into the second raw material to obtain a third raw material;

adding a CNT solvent into the third raw material to obtain a fourth raw material;

and preserving the fourth raw material in vacuum to obtain the anode slurry.

In an optional embodiment of the present invention, the step of gradually adding the first glue solution to the first dry powder to obtain a second raw material includes:

stirring at a first rotation speed while adding the first glue solution to the first dry powder;

and stirring the first glue solution at a second rotating speed for a first preset time after the first glue solution is added, so as to obtain the second raw material, wherein the first rotating speed is lower than the second rotating speed.

In an optional embodiment of the present invention, the stirring revolution rotation speed of the first rotation speed is 5rpm to 10rpm, the stirring rotation speed of the first rotation speed is 200rpm to 500rpm, the stirring revolution rotation speed of the second rotation speed is 30rpm to 80rpm, the stirring rotation speed of the first rotation speed is 1000rpm to 3000rpm, and the first preset time is 10min to 30 min.

In an alternative embodiment of the present invention, the step of adding the remaining NMP to the second raw material to obtain a third raw material comprises:

stirring at a third rotational speed during the addition of the remaining NMP to the second feedstock;

and stirring at a fourth rotating speed for a second preset time after the NMP is added, so as to obtain the third raw material, wherein the third rotating speed is less than the fourth rotating speed.

In an alternative embodiment of the invention, the stirring revolution speed of the third rotating speed is 10rpm-20rpm, and the stirring rotation speed of the third rotating speed is 300rpm-500 rp; the stirring revolution rotating speed of the fourth rotating speed is 30rpm-60rpm, and the stirring rotation rotating speed of the first rotating speed is 1500rpm-2500 rp; the second preset time is 30-40 min.

In an alternative embodiment of the present invention, the step of adding the CNT solvent to the third raw material to obtain the fourth raw material includes:

stirring at a fifth rotating speed for a third preset time in the process of adding CNT into the third raw material, wherein the stirring revolution rotating speed of the fifth rotating speed is 20rpm-50rpm, and the stirring rotation rotating speed of the fifth rotating speed is 1000rpm-2000 rp; the third preset time is 10min-20 min.

In an alternative embodiment of the present invention, the step of vacuum preserving the fourth raw material to obtain the positive electrode slurry includes:

vacuumizing to a first preset pressure, and stirring at a sixth rotating speed for a fourth preset time to obtain the anode slurry, wherein the first preset pressure is-0.085 Mpa, the stirring revolution rotating speed of the sixth rotating speed is 10-20 rpm, and the stirring rotation rotating speed of the sixth rotating speed is 300-500 rp; the fourth preset time is 5min-15 min.

The embodiment of the invention has the following beneficial effects: the preparation method of the positive electrode slurry comprises the steps of mixing PVDF accounting for the total amount of the PVDF in a first proportion with NMP accounting for a second proportion of the NMP to prepare a first glue solution; mixing the first main material, silicon carbon and the rest PVDF to obtain first dry powder in a dry mixing way; and gradually adding the first glue solution into the first dry powder and mixing to prepare the anode slurry. In the embodiment of the invention, silicon carbon is added into the first main material in a dry mixing mode and then wet mixing is carried out, so that the stability of the anode slurry can be improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a flowchart of a method for manufacturing a positive electrode slurry according to an embodiment of the present invention.

Fig. 2 is a flowchart illustrating a sub-step of step S200 of a method for manufacturing a positive electrode slurry according to an embodiment of the present invention.

Fig. 3 is a flowchart illustrating sub-steps of step S300 of a method for manufacturing a positive electrode slurry according to an embodiment of the present invention.

Fig. 4 is a flowchart illustrating sub-steps of step S310 of a method for manufacturing a positive electrode slurry according to an embodiment of the present invention.

Fig. 5 is a flowchart illustrating a sub-step of step S320 of a method for manufacturing a positive electrode slurry according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or a positional relationship based on that shown in the drawings or that the product of the present invention is used as it is, this is only for convenience of description and simplification of the description, and it does not indicate or imply that the device or the element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

Furthermore, the appearances of the terms "first," "second," and the like, if any, are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.

Examples

The embodiment provides a method for manufacturing positive electrode slurry, which is mainly used for manufacturing positive electrode slurry, and can improve the stability of the positive electrode slurry and reduce the influence caused by coating the positive electrode slurry, so that the charge and discharge performance and the energy density of a battery are improved, and the internal resistance is reduced.

In the lithium battery industry, compared with nickel-cadmium and nickel-hydrogen batteries, the lithium ion battery has the advantages of high specific energy, high working voltage, low self-discharge rate, long cycle life, no pollution, wide application range and the like. The preparation of the electrode slurry is the most critical ring in the whole process, and the quality of the electrode slurry directly influences whether the next process can be carried out. The slurry is prepared by uniformly mixing powder and liquid such as active substances, adhesives, solvents, thickeners and the like to form a non-Newtonian high-viscosity fluid, and the fluid needs to have certain viscosity, good fluidity and sufficiently small particle size. The electrode slurry is composed of a plurality of raw materials with different specific gravities and different particle sizes, and is prepared by mixing and dispersing solid and liquid phases, and the formed slurry belongs to non-Newtonian fluid. The lithium battery slurry is divided into two types of positive electrode slurry and negative electrode slurry, and the properties of the slurry are different due to different slurry systems, namely different oil properties and different water properties, so that the most common wet-type slurry making method is used in the industry at present to prepare the positive electrode slurry. The anode slurry manufactured by the method has poor stability, and the problems of thicker thickness, low capacity and the like easily occur in the coating process. The method for manufacturing the positive electrode slurry provided by the embodiment can improve the problems, improve the stability of the positive electrode slurry, and reduce the influence caused by coating the positive electrode slurry, thereby improving the charge and discharge performance and energy density of the battery, and reducing the internal resistance.

The raw materials for producing the positive electrode slurry are approximately as follows: the first main material accounts for 85-88% of the total weight of the slurry. Silicon carbon, which accounts for 8.5-9.5% of the total weight of the slurry; the first conductive agent accounts for 0.4-1% of the total weight of the slurry; PVDF, which accounts for 1.5 to 2.5 percent of the total weight of the sizing agent; the second conductive agent accounts for 0.5 to 1.5 percent of the total weight of the slurry; a solvent.

Referring to fig. 1, the method for manufacturing the positive electrode slurry provided by the embodiment includes the following steps:

and S100, mixing PVDF accounting for a first proportion of the total amount of PVDF and NMP accounting for a second proportion of the total amount of NMP to prepare glue to form a first glue solution.

In this example, PVDF refers to polyvinylidene fluoride and NMP refers to N-methylpyrrolidone. The first proportion is 75% and the second proportion is 65%. Firstly, mixing part of PVDF and part of NMP to form a first glue solution, finishing post-sealing treatment, and storing at 25 +/-5 ℃ for later use.

Wherein, when the step S100 is executed, the stirring revolution rotating speed is 10rpm-30rpm, and the stirring rotation rotating speed is 800rpm-1500 rpm. The stirring time is 10min-30 min.

Step S200, dry-mixing the first main material, the silicon carbon and the residual PVDF to obtain first dry powder.

In the embodiment, the silicon carbon is mainly silicon carbon, and the first main material, the silicon carbon and 25% of PVDF are mixed in a dry mixing mode to form first dry powder. The addition of silicon carbon can improve the capacity and stability of the final anode slurry.

Referring to fig. 2, step S200 may include step S210 and step S220.

Step S210, mixing the first main material and silicon carbon to obtain a first raw material.

In this example, in the process of mixing to obtain the first dry powder, the first main material and the silicon carbon are first mixed to obtain the first raw material, and in the process of mixing, in order to uniformly mix the first main material and the silicon carbon, the stirring revolution speed is 20rpm to 50rpm, and the stirring rotation speed is 800rpm to 1500 rpm. The stirring time is 3min-10 min.

In step S220, the remaining PVDF is gradually added to the first raw material to obtain a first dry powder.

In this example, the remaining PVDF and the entire first conductive agent were gradually added to the first raw material and dry-mixed to obtain a first dry powder.

During the mixing process, the remaining 25% of PVDF and the entire first conductive agent are added to the first raw material for dry mixing, and the mixture is uniformly stirred during the dry mixing process to produce a uniformly dispersed first dry powder.

In the stirring process, the stirring revolution speed is 20rpm-50rpm, and the stirring rotation speed is 1000rpm-2500 rpm. The stirring time is 10min-25 min.

Referring to fig. 1, in step S300, the first glue solution is gradually added to the first dry powder and mixed to obtain the positive electrode slurry.

In this embodiment, the first colloidal solution is gradually added to the first dry powder, and the mixture is stirred and mixed, so that the positive electrode slurry can be obtained.

Referring to fig. 3, step S300 may include step S310, step S320, step S330 and step S340.

And step S310, gradually adding the first glue solution into the first dry powder to obtain a second raw material.

In this embodiment, in the mixing process, the first glue solution is gradually and slowly added to the first dry powder, and the first dry powder is gradually stirred in the adding process, so that the first glue solution can be uniformly mixed with the first dry powder.

Referring to fig. 4, step S310 may include step S312 and step S314.

Step S312, the first glue solution is added to the first dry powder while stirring at the first rotation speed.

In this embodiment, when the first glue solution is added to the first dry powder, the first glue solution is stirred at a first rotation speed, which is relatively low, so that the first glue solution and the first dry powder can be better kneaded to prevent agglomeration.

And step S314, stirring at a second rotating speed for a first preset time after the first glue solution is added to obtain a second raw material. Wherein the first rotational speed is less than the second rotational speed.

After the first glue solution is added, the first glue solution has certain viscosity, and if the first glue solution is in a dough shape, the first glue solution can be pasted, the first glue solution and the first dry powder can be well kneaded more uniformly, the first glue solution needs to be stirred at a second higher rotating speed, and the dispersing shaft and the stirring slurry need to be scraped. Meanwhile, the temperature needs to be reduced, and the temperature is kept at about 25 +/-10 ℃.

The stirring revolution rotating speed of the first rotating speed is 5-10 rpm, the stirring rotation rotating speed of the first rotating speed is 200-500 rpm, the stirring revolution rotating speed of the second rotating speed is 30-80 rpm, the stirring rotation rotating speed of the first rotating speed is 1000-3000 rpm, and the first preset time is 10-30 min.

Referring to fig. 3, in step S320, the remaining NMP is added to the second raw material to obtain a third raw material.

In this example, after the kneading of the second raw material was completed, the remaining 35% of NMP was added to the second raw material to obtain a third raw material.

Referring to fig. 5, step S320 may include step S322 and step S324.

In step S322, the second feedstock is stirred at a third rotational speed while the remaining NMP is added.

Similarly, the second feedstock is stirred at a third, lower speed during the addition of NMP to the second feedstock, allowing NMP to be uniformly kneaded with the second feedstock.

And step S324, stirring at a fourth rotating speed for a second preset time after the NMP is added, and obtaining a third raw material. Wherein the third rotational speed is less than the fourth rotational speed.

In this example, after the NMP addition was completed, the third feedstock was stirred at a fourth, greater rotational speed to enable the third feedstock to be kneaded thoroughly, improving the homogeneity of the third feedstock.

The stirring revolution rotating speed of the third rotating speed is 10rpm-20rpm, and the stirring rotation rotating speed of the third rotating speed is 300rpm-500 rp; the stirring revolution speed of the fourth rotating speed is 30rpm-60rpm, and the stirring rotation speed of the fourth rotating speed is 1500rpm-2500 rp; the second preset time is 30min-40 min.

Referring to fig. 3, in step S330, a CNT solvent is added to the third raw material to obtain a fourth raw material.

Stirring at a fifth rotating speed for a third preset time in the process of adding the CNT into the third raw material, wherein the stirring revolution rotating speed of the fifth rotating speed is 20-50 rpm, and the stirring rotation rotating speed of the fifth rotating speed is 1000-2000 rp; the third preset time is 10min-20 min.

And step S340, storing the fourth raw material in vacuum to obtain the anode slurry.

Vacuumizing to a first preset pressure, and stirring at a sixth rotating speed for a fourth preset time to obtain anode slurry, wherein the first preset pressure is-0.085 Mpa, the stirring revolution rotating speed of the sixth rotating speed is 10-20 rpm, and the stirring rotation rotating speed of the sixth rotating speed is 300-500 rp; the fourth preset time is 5min-15 min.

In summary, in the method for manufacturing the cathode slurry provided in this embodiment, the silicon carbon is added to the first main material in a dry mixing manner, and then wet mixing is performed, so that the stability of the cathode slurry can be improved.

The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.